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Plasma energy recycle and conversion of polymeric (MSW) waste. Final report
Knight, Richard; Grossman, Elihu D.
Final report summarizing research project results of studies of the thermal plasma recycling of polymers, including polyethylene and polypropylene. High levels of recovery of monomers were obtained from the process developed under this study.
Regulation of Plasma Membrane Recycling by CFTR
NASA Astrophysics Data System (ADS)
Bradbury, Neil A.; Jilling, Tamas; Berta, Gabor; Sorscher, Eric J.; Bridges, Robert J.; Kirk, Kevin L.
The gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) is defective in patients with cystic fibrosis. Although the protein product of the CFTR gene has been proposed to function as a chloride ion channel, certain aspects of its function remain unclear. The role of CFTR in the adenosine 3',5'-monophosphate (cAMP)-dependent regulation of plasma membrane recycling was examined. Adenosine 3',5'-monophosphate is known to regulate endocytosis and exocytosis in chloride-secreting epithelial cells that express CFTR. However, mutant epithelial cells derived from a patient with cystic fibrosis exhibited no cAMP-dependent regulation of endocytosis and exocytosis until they were transfected with complementary DNA encoding wild-type CFTR. Thus, CFTR is critical for cAMP-dependent regulation of membrane recycling in epithelial tissues, and this function of CFTR could explain in part the pleiotropic nature of cystic fibrosis.
Transport of Recycled Deuterium to the Plasma Core in TFTR
Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Skinner, C.H.; et al
We report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas 2, 2176 (1995)]. We have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. We find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.
Transport of recycled deuterium to the plasma core in TFTR
Skinner, C.H.; Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Ramsey, A.T.; Stotler, D.P.; Strachan, J.D.
The authors report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR). They have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. They find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.
Energy implications of glass-container recycling
Gaines, L L; Mintz, M M
This report addresses the question of whether glass-container recycling actually saves energy. Glass-container production in 1991 was 10{sup 7} tons, with cullet making up about 30% of the input to manufacture. Two-thirds of the cullet is postconsumer waste; the remainder is in-house scrap (rejects). Most of the glass recycled is made into new containers. Total primary energy consumption includes direct process-energy use by the industry (adjusted to account for the efficiency of fuel production) plus fuel and raw-material transportation and production energies; the grand total for 1991 is estimated to be about 168 {times} 10{sup 12} Btu. The total primary energy use decreases as the percent of glass recycled rises, but the maximum energy saved is only about 13%. If distance to the landfill is kept fixed and that to the recovery facility multiplied by about eight, to 100 mi, a break-even point is reached, and recycling saves no energy. Previous work has shown that to save energy when using glass bottles, reuse is the clear choice. Recycling of glass does not save much energy or valuable raw material and does not reduce air or water pollution significantly. The most important impacts are the small reduction of waste sent to the landfill and increased production rates at glass plants.
Energy return on investment of used nuclear fuel recycling
N-EROI calculates energy return on investment (EROI) for recycling of used nublear fuel in four scenarios: one-pass recycle in light water reactors; two-pass recycle in light water reactors; mulit-pass recycle in burner fast reactora; one-pass recycle in breeder fast reactors.
Energy implications of recycling packaging materials
Gaines, L.L.; Stodolsky, F.
In 1992, Congress sought to rewrite the United States comprehensive solid waste legislation -- the Resource Conservation and Recovery Act (RCRA). Commodity-specific recycling rates were proposed for consumer-goods packaging materials and newsprint We compare the impacts on energy, materials use, and landfill volume of recycling at those rates to the impacts for alternative methods of material disposition to determine the optimum for each material. After products have served their intended uses, there are several alternative paths for material disposition. These include reuse, recycling to the same product, recycling to a lower-valued product, combustion for energy recovery, incineration without energy recovery, and landfill. Only options considered to be environmentally sound are Included. Both houses of Congress specifically excluded combustion for energy recovery from counting towards the recovery goats, probably because combustion is viewed as a form of disposal and is therefore assumed to waste resources and have n environmental effects. However, co-combustion in coal-fired plants or combustion in appropriately pollution-controlled waste-to-energy plants Is safe, avoids landfill costs, and can displace fossil fuels. In some cases, more fossil fuels can be displaced by combustion than by recycling. We compare the alternative life-cycle energies to the energies for producing the products from virgin materials. Results depend on the material and on the objective to be achieved. There are trade-offs among possible goals. For instance, paper packaging recycling conserves trees but may require greater fossil-fuel input than virgin production. Therefore, the objectives for proposed legislation must be examined to see whether they can most effectively be achieved by mandated recycling rates or by other methods of disposition. The optimal choices for the United States may not necessarily be the same as those for Europe and other parts of the world.
NASA Astrophysics Data System (ADS)
Goto, Junya; Santorelli, Michael
Recycling systems are classified into those employing typically three methods, and the progress of each method is described. In mechanical recycling, powders of phenolic materials are recovered via a mechanical process and reused as fillers or additives in virgin materials. The effects to flowability, curability, and mechanical properties of the materials are explained. In feedstock recycling, monomers, oligomers, or oils are recovered via chemical processes and reused as feedstock. Pyrolysis, solvolysis or hydrolysis, and supercritical or subcritical fluid technology will also be introduced. When using a subcritical fluid of phenol, the recycled material maintains excellent properties similar to the virgin material, and a demonstration plant has been constructed to carry out mass production development. In energy recovery, wastes of phenolic materials are used as an alternative solid fuel to coal because they are combustible and have good calorific value. Industrial wastes of these have been in practical use in a cement plant. Finally, it is suggested that the best recycling method should be selected according to the purpose or situation, because every recycling method has both strengths and weaknesses. Therefore, quantitative and objective evaluation methods in recycling are desirable and should be established.
Biomass recycling heat technology and energy products
NASA Astrophysics Data System (ADS)
Tabakaev, R. B.; Gergelizhiu, P. S.; Kazakov, A. V.; Zavorin, A. S.
Relevance is determined by necessity of utilizing of local low-grade fuels by energy equpment. Most widespread Tomsk oblast (Russian Federation region) low-grade fuels are described and listed. Capability of utilizing is analysed. Mass balances of heat-technology conversion materials and derived products are described. As a result, recycling capability of low-grade fuels in briquette fuel is appraised.
ERIC Educational Resources Information Center
Sinker, Barbara
Discusses the range of benefits resulting from recycling efforts and projects. Presents information and data related to the recycling of metals, cans, paper, fans, and plastics. Suggestions for motivating and involving youth in recycling programs are also offered. (ML)
Energy Return on Investment - Fuel Recycle
Halsey, W; Simon, A J; Fratoni, M; Smith, C; Schwab, P; Murray, P
This report provides a methodology and requisite data to assess the potential Energy Return On Investment (EROI) for nuclear fuel cycle alternatives, and applies that methodology to a limited set of used fuel recycle scenarios. This paper is based on a study by Lawrence Livermore National Laboratory and a parallel evaluation by AREVA Federal Services LLC, both of which were sponsored by the DOE Fuel Cycle Technologies (FCT) Program. The focus of the LLNL effort was to develop a methodology that can be used by the FCT program for such analysis that is consistent with the broader energy modeling community, and the focus of the AREVA effort was to bring industrial experience and operational data into the analysis. This cooperative effort successfully combined expertise from the energy modeling community with expertise from the nuclear industry. Energy Return on Investment is one of many figures of merit on which investment in a new energy facility or process may be judged. EROI is the ratio of the energy delivered by a facility divided by the energy used to construct, operate and decommission that facility. While EROI is not the only criterion used to make an investment decision, it has been shown that, in technologically advanced societies, energy supplies must exceed a minimum EROI. Furthermore, technological history shows a trend towards higher EROI energy supplies. EROI calculations have been performed for many components of energy technology: oil wells, wind turbines, photovoltaic modules, biofuels, and nuclear reactors. This report represents the first standalone EROI analysis of nuclear fuel reprocessing (or recycling) facilities.
Energy transmission using recyclable quantum entanglement.
Ye, Ming-Yong; Lin, Xiu-Min
It is known that faster-than-light (FTL) transmission of energy could be achieved if the transmission were considered in the framework of non-relativistic classical mechanics. Here we show that FTL transmission of energy could also be achieved if the transmission were considered in the framework of non-relativistic quantum mechanics. In our transmission protocol a two-spin Heisenberg model is considered and the energy is transmitted by two successive local unitary operations on the initially entangled spins. Our protocol does not mean that FTL transmission can be achieved in reality when the theory of relativity is considered, but it shows that quantum entanglement can be used in a recyclable way in energy transmission. PMID:27465431
Energy transmission using recyclable quantum entanglement
NASA Astrophysics Data System (ADS)
Ye, Ming-Yong; Lin, Xiu-Min
It is known that faster-than-light (FTL) transmission of energy could be achieved if the transmission were considered in the framework of non-relativistic classical mechanics. Here we show that FTL transmission of energy could also be achieved if the transmission were considered in the framework of non-relativistic quantum mechanics. In our transmission protocol a two-spin Heisenberg model is considered and the energy is transmitted by two successive local unitary operations on the initially entangled spins. Our protocol does not mean that FTL transmission can be achieved in reality when the theory of relativity is considered, but it shows that quantum entanglement can be used in a recyclable way in energy transmission.
Recycling legislation: A balanced approach for opening biomass energy opportunities
Easterly, J.L.
State recycling legislation represents one of the barriers to using wood wastes for energy. Although many states are setting recycling goals that often mandate a significant portion of the waste stream be recycled, legislation in the same states specifically excludes wood-to-energy as a recycling option. A significant supply of yard waste and wood waste could be available for biomass power generation of recycling legislation credited the use of wood-to-energy as an acceptable recycling alternative. This article discusses in some detail the approach Florida legislation has pursued. It could be a model for other innovative recycling programs. It provides checks and balances as well as reasonable compromises that help to avoid or minimize objections by the environmental community.
Mildly Recycled Pulsars at High-Energies
NASA Astrophysics Data System (ADS)
Pellizzoni, A.
Mildly recyled pulsars (MRP), conventionally defined as neutron star having spin period in the 20-100 ms range and surface magnetic field <1011 Gauss, probably rise from binary systems (disrupted or not) with an intermediate or an high mass companion. Despite their relatively low spin-down energies compared to the ``fully'' recycled millisecond pulsars (arising from common low mass X-ray binaries), nearby MRPs can be detected by deep X-ray observations and by timing analysis of the very long data span provided by gamma-ray space detectors. The discovery of peculiar timing and spectral properties, possibly transitional, of the MRPs can be of the utmost importance to link different classes of neutron stars and study their evolution.
The report gives results of a study of energy conservation effects of point source recycle with high-temperature hyperfiltration (HF) in the textile industry. (HF and ultrafiltration (UF) are pressure-driven membrane processes which have potential for recycle of water, energy, an...
Recent trends in automobile recycling: An energy and economic assessment
Curlee, T.R.; Das, S.; Rizy, C.G.; Schexanyder, S.M.
Recent and anticipated trends in the material composition of domestic and imported automobiles and the increasing cost of landfilling the non-recyclable portion of automobiles (automobile shredder residue or ASR) pose questions about the future of automobile recycling. This report documents the findings of a study sponsored by the US Department of Energy`s Office of Environmental Analysis to examine the impacts of these and other relevant trends on the life-cycle energy consumption of automobiles and on the economic viability of the domestic automobile recycling industry. More specifically, the study (1) reviewed the status of the automobile recycling industry in the United States, including the current technologies used to process scrapped automobiles and the challenges facing the automobile recycling industry; (2) examined the current status and future trends of automobile recycling in Europe and Japan, with the objectives of identifying ``lessons learned`` and pinpointing differences between those areas and the United States; (3) developed estimates of the energy system impacts of the recycling status quo and projections of the probable energy impacts of alternative technical and institutional approaches to recycling; and (4) identified the key policy questions that will determine the future economic viability of automobile shredder facilities in the United States.
Time-dependent recycling modeling with edge plasma transport codes
NASA Astrophysics Data System (ADS)
Pigarov, A.; Krasheninnikov, S.; Rognlien, T.; Taverniers, S.; Hollmann, E.
First,we discuss extensions to Macroblob approach which allow to simulate more accurately dynamics of ELMs, pedestal and edge transport with UEDGE code. Second,we present UEDGE modeling results for H mode discharge with infrequent ELMs and large pedestal losses on DIII-D. In modeled sequence of ELMs this discharge attains a dynamic equilibrium. Temporal evolution of pedestal plasma profiles, spectral line emission, and surface temperature matching experimental data over ELM cycle is discussed. Analysis of dynamic gas balance highlights important role of material surfaces. We quantified the wall outgassing between ELMs as 3X the NBI fueling and the recycling coefficient as 0.8 for wall pumping via macroblob-wall interactions. Third,we also present results from multiphysics version of UEDGE with built-in, reduced, 1-D wall models and analyze the role of various PMI processes. Progress in framework-coupled UEDGE/WALLPSI code is discussed. Finally, implicit coupling schemes are important feature of multiphysics codes and we report on the results of parametric analysis of convergence and performance for Picard and Newton iterations in a system of coupled deterministic-stochastic ODE and proposed modifications enhancing convergence.
Design and test of a large plasma torch for environmental recycling
Tuszewski, M.
A 2.5-inch inductive plasma torch has been tested with up to 600 kW rf power and with argon, nitrogen, and oxygen gases. A complete power balance is obtained from electrical, thermal, and radiation measurements. These data indicate that torch efficiencies of up to 30% are obtained with molecular gases, while efficiencies around 15% are obtained with argon. The efficiencies obtained with molecular gases almost triple earlier torch efficiencies and confirm substantially the predictions of a torch model developed during a previous CRADA. Torch efficiencies of up to 50% could be obtained in future tests with an improved rf power supply, with steam gas, and with larger torch dimensions. Future applications of the Plasma Energy Recycle and Conversion (PERC) process could include the high explosives of DOE`s nuclear weapons, chemical and biological remediation, and the treatment and volume reduction of radioactive mixed waste.
Plasma exchange-based plasma recycling dialysis system as a potential platform for artificial liver support.
Nishimura, Akimasa; Umehara, Yutaka; Umehara, Minoru; Hakamada, Kenichi; Narumi, Shunji; Toyoki, Yoshikazu; Yoshihara, Shuichi; Sasaki, Mutsuo
We developed a plasma recycling dialysis (PRD) system based on plasma exchange (PE). In this system, rapid reduction of toxic substances and restitution of deficient essential substances are performed by PE, and subsequent blood purification is performed by dialysis between separated plasma recycled over a purification device and the patient's blood across the membrane of the plasma separator. This study was performed to demonstrate the safety and efficacy of this system. Hyperbilirubinemia was induced by ligating the bile duct in pigs, and 7 days later, only PE for 2 h (group PE) or PE for 2 h followed by PRD for 6 h (group PE + PRD) was performed. The separated plasma was recycled over anion-exchange resin through the extra fiber space of the plasma separator. The safety and efficacy of this system were evaluated based on the values of hemodynamic and laboratory parameters. Transfer from PE to PRD was completed in a few minutes. The hemodynamic status and blood cells counts were stable and hemolysis was not observed during the procedure. In the PE + PRD group, the concentrations of total bile acids continuously decreased (pretreatment, 155.5 +/- 40.6 microM; 2 h [end of PE], 76.1 +/- 14.4 microM; 8 h [end of PRD], 25.8 +/- 9.1 microM) and the value was significantly lower than in the PE group after 6 h. The total bilirubin also continuously decreased during PRD (pretreatment, 55.3 +/- 11.5 microM; 2 h [end of PE], 33.8 +/- 8.4 microM; 8 h [end of PRD], 18.6 +/- 7.7 microM) and was significantly lower than in the PE group after 4 h. No significant change was observed in other laboratory values. This PE-based PRD system allowed a swift transfer from PE to sorbent-based blood purification. The safety of this system was demonstrated and the removal of toxic substances was significant. This study confirmed the clinical utility of this system as a platform for artificial liver support. PMID:16911318
The Low-Recycling Lithium Boundary and Implications for Plasma Transport
NASA Astrophysics Data System (ADS)
Granstedt, Erik Michael
Pumping of incident hydrogen and impurity ions by lithium enables control of the particle inventory and fueling profile in magnetic-confined plasmas, and may raise the plasma temperature near the wall. As a result, the density gradient is expected to contribute substantially to the free-energy, affecting particle and thermal transport from micro-turbulence which is typically the dominant transport mechanism in high-temperature fusion experiments. Transport in gyrokinetic simulations of density-gradient-dominated profiles is characterized by a small linear critical gradient, large particle flux, and preferential diffusion of cold particles. As a result, the heat flux is below 5/2 or even 3/2 times the particle flux, usually assumed to be the minimum for convection. While surprising, this result is consistent with increasing entropy. Coupled TEM-ITG (ion-temperature-gradient) simulations using η e = ηi find η = ∇ T/∇n ≈ 0.8 maximizes the linear critical pressure gradient, which suggests that experiments operating near marginal ITG stability with larger η would increase the linear critical pressure gradient by transferring free-energy from the temperature gradient to the density gradient. Simulations were performed with profiles predicted for the Lithium Tokamak Experiment (LTX) if ion thermal transport was neoclassical, while electron thermal transport and particle transport were a fixed ratio above the neoclassical level. A robust TEM instability was found for the outer half radius, while the ITG was found to be driven unstable as well during gas puff fueling. This suggests that TEM transport will be an important transport mechanism in high-temperature low-recycling fusion experiments, and in the absence of stabilizing mechanisms, may dominate over neoclassical transport. A diagnostic suite has been developed to measure hydrogen and impurity emission in LTX in order to determine the lower bound on recycling that can be achieved in a small tokamak using
Plasma exchange-based plasma recycling dialysis system as an artificial liver support.
Takahashi, Kentaro; Umehara, Yutaka; Umehara, Minoru; Nishimura, Akimasa; Narumi, Shunji; Toyoki, Yoshikazu; Hakamada, Kenichi; Yoshihara, Syuichi; Sasaki, Mutsuo
We developed a plasma recycling dialysis (PRD) system based on plasma exchange (PE). In this system, rapid reduction of toxic substances and restitution of deficient essential substances are performed by PE and subsequent blood purification is performed by dialysis between separated plasma recycled over a purification device and the patient's blood across the membrane of a plasma separator. To demonstrate the safety and efficacy of this system, we used a pig model of fulminant hepatic failure (FHF) and anion exchange resin, activated charcoal and hemodialysis for the purification device. FHF was induced by intraportal administration of alpha-amanitine (0.1 mg/kg) and lipopolysaccharides (1 microg/kg) in pigs. Three groups of animals were studied: group 1, diseased controls (N = 4); group 2, PE group (N = 4), 16 h after drug infusion the pigs underwent PE of approximately 1.2 L for 2 h; and group 3, PE + PRD group (N = 4), the pigs underwent PE followed by PRD for 6 h. The hemodynamic status of all animals was stable during the procedure. In group 3, the values of ammonia, total bile acid and total bilirubin continuously decreased and were significantly lower than those of the animals in group 2 24 h after the induction of FHF. The Fischer ratio was significantly higher than in group 2 after 24 h. Group 3 pigs maintained a higher level of consciousness and survived longer than group 2 pigs. Safety of this PE-based PRD system was demonstrated and the removal of toxic substances was significant. This study confirmed the clinical utility of this system as an artificial liver support. PMID:18789112
Energy impacts of recycling disassembly material in residential buildings.
Gao, Weijun; Ariyama, Takahiro; Ojima, Toshio; Meier, Alan
In order to stop the global warmth due to the CO2 concentration, the energy use should be decreased. The investment of building construction industry in Japan is about 20 percent of GDP. This fraction is much higher than in most developed countries. That results the Japanese building construction industry including residential use consumes about one third of all energy and resources of the entire industrial sectors. In order to save energy as well as resource, the recycle of the building materials should be urgent to be carried out. In this paper, we focus on the potential energy savings with a simple calculated method when the building materials or products are manufactured from recycled materials. We examined three kinds of residential buildings with different construction techniques and estimated the decreased amount of energy consumption and resources resulting from use of recycled materials. The results have shown for most building materials, the energy consumption needed to remake housing materials from recycled materials is lower than that to make new housing materials. The energy consumption of building materials in all case-study housing can be saved by at least 10 percent. At the same time, the resource, measured by mass of building materials (kg) can be decreased by over 50 percent.
Goldenring, James R
The endosomal membrane recycling system represents a dynamic conduit for sorting and re-exporting internalized membrane constituents. The recycling system is composed of multiple tubulovesicular recycling pathways that likely confer distinct trafficking pathways for individual cargoes. In addition, elements of the recycling system are responsible for assembly and maintenance of apical membrane specializations including primary cilia and apical microvilli. The existence of multiple intersecting and diverging recycling tracks likely accounts for specificity in plasma membrane recycling trafficking. PMID:26022676
Transport of carbon ion test particles and hydrogen recycling in the plasma of the Columbia tokamak HBT'' (High Beta Tokamak)
Wang, Jian-Hua.
Carbon impurity ion transport is studied in the Columbia High Beta Tokamak (HBT), using a carbon tipped probe which is inserted into the plasma (n{sub e} {approx} 1 {minus} 5 {times} 10{sup 14} (cm{sup {minus}3}), T{sub e} {approx} 4 {minus} 10 (eV), B{sub t} {approx} 0.2 {minus} 0.4(T)). Carbon impurity light, mainly the strong lines of C{sub II}(4267A, emitted by the C{sup +} ions) and C{sub III} (4647A, emitted by the C{sup ++} ions), is formed by the ablation or sputtering of plasma ions and by the discharge of the carbon probe itself. The diffusion transport of the carbon ions is modeled by measuring the space-and-time dependent spectral light emission of the carbon ions with a collimated optical beam and photomultiplier. The point of emission can be observed in such a way as to sample regions along and transverse to the toroidal magnetic field. The carbon ion diffusion coefficients are obtained by fitting the data to a diffusion transport model. It is found that the diffusion of the carbon ions is classical'' and is controlled by the high collisionality of the HBT plasma; the diffusion is a two-dimensional problem and the expected dependence on the charge of the impurity ion is observed. The measurement of the spatial distribution of the H{sub {alpha}} emissivity was obtained by inverting the light signals from a 4-channel polychromator, the data were used to calculate the minor-radial influx, the density, and the recycling time of neutral hydrogen atoms or molecules. The calculation shows that the particle recycling time {tau}{sub p} is comparable with the plasma energy confinement time {tau}{sub E}; therefore, the recycling of the hot plasma ions with the cold neutrals from the walls is one of the main mechanisms for loss of plasma energy.
Energy Return on Investment from Recycling Nuclear Fuel
This report presents an evaluation of the Energy Return on Investment (EROI) from recycling an initial batch of 800 t/y of used nuclear fuel (UNF) through a Recycle Center under a number of different fuel cycle scenarios. The study assumed that apart from the original 800 t of UNF only depleted uranium was available as a feed. Therefore for each subsequent scenario only fuel that was derived from the previous fuel cycle scenario was considered. The scenarios represent a good cross section of the options available and the results contained in this paper and associated appendices will allow for other fuel cycle options to be considered.
Energy conservation through recycling of factory asphalt roofing waste
Shepherd, P.B.; Powers, T.J. . Manville Technical Center); Hardy, J.; Maloof, R.; Patenaude, C.; Zilfi, J. )
Prior DOE laboratory research showed that it was possible to recover the energy resource represented in factory shingle waste. This waste could be processed and recycled into the asphalt composition used to make new shingles. This bench-scale research concluded that factory experiments were all that were needed to provide a basis for commercial implementation. The project reported here completed that full scale research. Factory fiber glass shingle waste was processed to a form suitable for recycling. The processed waste was then mixed into the asphalt used to make new shingles. Process parameters and shingle quality were measured to provide a basis for commercial implementation.
Energy savings in aluminum production, use, and recycling
Russell, A.S.
Aluminum and energy have been intertwined since the initial isolation of the metal from its ore, and industry growth has depended on great quantities of inexpensive, available energy. In response to the modern need, the industry has significantly decreased the energy required for the chemical steps in aluminum production. That aggressive effort is catalogued here. The energy saving potential of a new smelting process is mentioned. The tremendous energy reduction achieved by recycling and improved design of the aluminum beverage can is detailed, and the potential for similar advantages for other products is presented. Finally, the important role of light weight aluminum in decreasing the nation's energy requirement for transportation is discussed.
Non-local transport in a tokamak plasma divertor with recycling
Abou-Assaleh, Z.; Petravic, M.; Vesey, R.; Matte, J.P.; Johnston, T.W.
The plasma transport, particle and energy fluxes, near the diverter plate with high recycling has been modeled by using an electron kinetic code (Fokker-Planck International) in conjunction with a two-fluid ambipolar code. We include the effects of ionization and excitation of the hydrogen atoms. The electron energy distribution calculated from the kinetic code shows a large deviation from Maxwellian especially near the plate. This deviation from Maxwellian is due to the non-local transport of the suprathermal electrons from the SOL, and due also to the absorption of the fast electrons by the target plate. The heat flux near the plate is shown to be nonlocal, in that it is not determined uniquely by the local plasma parameters. Therefore the classical transport coefficients in the fluid model must be modified by including a nonlocal effect to produce the kinetic results. The kinetic calculation is compared with those of the fluid code with different values of the electron heat flux limiter factor (f). To reduce the computer load, the initial condition we used corresponds to the equilibrium solution already found with the fluid code with f=0.2. The fluid and Fokker-Planck codes are relaxed until all transients associated with electron dynamics have disappeared. In section 2, we present the kinetic code. The fluid code is presented in section 3. The boundary conditions used in these simulations are given in section 4. Finally the results and conclusion of these simulations are presented in section 5.
High energy plasma accelerators
Tajima, T.
Colinear intense laser beams ..omega../sub 0/, kappa/sub 0/ and ..omega../sub 1/, kappa/sub 1/ shone on a plasma with frequency separation equal to the electron plasma frequency ..omega../sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ..omega../sub pe//e of the order of 1GeV/cm for a plasma density of 10/sup 18/ cm/sup -3/ through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed.
Energy impacts in producing and recycling EV batteries
This article reports that choosing the best EV battery involves more than a quest for greater range per charge, as total energy cycle assessment of batteries demonstrates. Much has been written about the performance characteristics of electric vehicle (EV) batteries, but information about materials and the production and recycling processes is not as readily available. Such information has not been the primary focus of interest, since designs and processes are still under development, and much of the information is proprietary. An overview of four electric vehicle batteries--advanced lead/acid, sodium/sulfur, nickel/cadmium and nickel/metal hydride--highlights significant differences in energy consumption during production and recycling of materials used in the batteries. Certain realities apply to these batteries, despite their technical distinctions. First, and most obvious, the batteries will make up a significant fraction, 20--40%, of vehicle mass. Impacts are increased because some batteries with lifetimes shorter than the vehicle`s will need replacement at least once. Another insight is that battery recyclability is being considered at the design stage because the electric vehicle is being born green, that is, environmentally benign from the onset. In contrast to the small consumer cells now simply being shredded, EV batteries will be large enough to warrant disassembly and material segregation as the first step in recycling. Electrode and electrolyte materials in advanced batteries are nonstandard in the automotive industry, so process information is not readily available.
Concrete with carpet recyclates: suitability assessment by surface energy evaluation.
Schmidt, H; Cieślak, M
Worn out textile floor coverings are burdensome wastes that are degraded in landfill sites after a very long period of time. One of the ways to manage this kind of waste may be the use of carpet recyclate (CR) as an additive for concrete reinforcement. Therefore, an attempt was made to predict the effects of recyclate additives on the durability a concrete-carpet mixture by employing the method of assessing surface properties of components in the concrete-carpet recyclates composite. Testing was performed on carpet wastes, containing polyamide (PA) and polypropylene (PP) piles and butadiene-styrene resin with chalk filler (BSC) as back coating, to assess the suitability of CR additive for concrete reinforcement by surface energy evaluation. Based on the measurements of contact angles, the free surface energy of recyclate components was determined. The reversible work of adhesion at the interface between these components in dry and wet states was also calculated. The results show that CR with both PA and PP fibers form a strong and water-resistant bond with concrete. PMID:17611097
Spent nuclear fuel recycling with plasma reduction and etching
Kim, Yong Ho
A method of extracting uranium from spent nuclear fuel (SNF) particles is disclosed. Spent nuclear fuel (SNF) (containing oxides of uranium, oxides of fission products (FP) and oxides of transuranic (TRU) elements (including plutonium)) are subjected to a hydrogen plasma and a fluorine plasma. The hydrogen plasma reduces the uranium and plutonium oxides from their oxide state. The fluorine plasma etches the SNF metals to form UF6 and PuF4. During subjection of the SNF particles to the fluorine plasma, the temperature is maintained in the range of 1200-2000 deg K to: a) allow any PuF6 (gas) that is formed to decompose back to PuF4 (solid), and b) to maintain stability of the UF6. Uranium (in the form of gaseous UF6) is easily extracted and separated from the plutonium (in the form of solid PuF4). The use of plasmas instead of high temperature reactors or flames mitigates the high temperature corrosive atmosphere and the production of PuF6 (as a final product). Use of plasmas provide faster reaction rates, greater control over the individual electron and ion temperatures, and allow the use of CF4 or NF3 as the fluorine sources instead of F2 or HF.
Coherent parasitic energy loss of the recycler beam
K.Y. Ng
Parasitic energy loss of the particle beam in the Recycler Ring is discussed. The long beam confined between two barrier waves has a spectrum that falls off rapidly with frequency. Discrete summation over the revolution harmonics must be made to obtain the correct energy loss per particle per turn, because only a few lower revolution harmonics of real part of the longitudinal impedance contribute to the parasitic energy loss. The longitudinal impedances of the broadband rf cavities, the broadband resistive-wall monitors, and the resistive wall of the vacuum chamber are discussed. They are the main sources of the parasitic energy loss.
Recycling Energy to Restore Impaired Ankle Function during Human Walking
Collins, Steven H.; Kuo, Arthur D.
Background Humans normally dissipate significant energy during walking, largely at the transitions between steps. The ankle then acts to restore energy during push-off, which may be the reason that ankle impairment nearly always leads to poorer walking economy. The replacement of lost energy is necessary for steady gait, in which mechanical energy is constant on average, external dissipation is negligible, and no net work is performed over a stride. However, dissipation and replacement by muscles might not be necessary if energy were instead captured and reused by an assistive device. Methodology/Principal Findings We developed a microprocessor-controlled artificial foot that captures some of the energy that is normally dissipated by the leg and "recycles" it as positive ankle work. In tests on subjects walking with an artificially-impaired ankle, a conventional prosthesis reduced ankle push-off work and increased net metabolic energy expenditure by 23% compared to normal walking. Energy recycling restored ankle push-off to normal and reduced the net metabolic energy penalty to 14%. Conclusions/Significance These results suggest that reduced ankle push-off contributes to the increased metabolic energy expenditure accompanying ankle impairments, and demonstrate that energy recycling can be used to reduce such cost. PMID:20174659
Thermal Recycling of Waelz Oxide Using Concentrated Solar Energy
NASA Astrophysics Data System (ADS)
Tzouganatos, N.; Matter, R.; Wieckert, C.; Antrekowitsch, J.; Gamroth, M.; Steinfeld, A.
The dominating Zn recycling process is the so-called Waelz process. Waelz oxide (WOX), containing 55-65% Zn in oxidic form, is mainly derived from electric arc furnace dust produced during recycling of galvanized steel. After its wash treatment to separate off chlorides, WOX is used as feedstock along with ZnS concentrates for the electrolytic production of high-grade zinc. Novel and environmentally cleaner routes for the purification of WOX and the production of Zn are investigated using concentrated solar energy as the source of high-temperature process heat. The solar-driven clinkering of WOX and its carbothermal reduction were experimentally demonstrated using a 10 kWth packed-bed solar reactor. Solar clinkering at above 1265°C reduced the amount of impurities below 0.1 wt.%. Solar carbothermal reduction using biocharcoal as reducing agent in the 1170-1320°C range yielded 90 wt.% Zn.
VAMP8-dependent fusion of recycling endosomes with the plasma membrane facilitates T lymphocyte cytotoxicity
Marshall, Misty R.; Pattu, Varsha; Halimani, Mahantappa; Maier-Peuschel, Monika; Müller, Martha-Lena; Becherer, Ute; Hong, Wanjin; Hoth, Markus; Tschernig, Thomas
Cytotoxic T lymphocytes (CTLs) eliminate infected and neoplastic cells through directed release of cytotoxic granule contents. Although multiple SNARE proteins have been implicated in cytotoxic granule exocytosis, the role of vesicular SNARE proteins, i.e., vesicle-associated membrane proteins (VAMPs), remains enigmatic. VAMP8 was posited to represent the cytotoxic granule vesicular SNARE protein mediating exocytosis in mice. In primary human CTLs, however, VAMP8 colocalized with Rab11a-positive recycling endosomes. Upon stimulation, these endosomes rapidly trafficked to and fused with the plasma membrane, preceding fusion of cytotoxic granules. Knockdown of VAMP8 blocked both recycling endosome and cytotoxic granule fusion at immune synapses, without affecting activating signaling. Mechanistically, VAMP8-dependent recycling endosomes deposited syntaxin-11 at immune synapses, facilitating assembly of plasma membrane SNARE complexes for cytotoxic granule fusion. Hence, cytotoxic granule exocytosis is a sequential, multivesicle fusion process requiring VAMP8-mediated recycling endosome fusion before cytotoxic granule fusion. Our findings imply that secretory granule exocytosis pathways in other cell types may also be more complex than previously appreciated. PMID:26124288
Conversion of broadband to narrowband thermal emission through energy recycling
NASA Astrophysics Data System (ADS)
de Zoysa, Menaka; Asano, Takashi; Mochizuki, Keita; Oskooi, Ardavan; Inoue, Takuya; Noda, Susumu
Converting from a broadband to a narrowband thermal emission spectrum with minimal loss of energy is important in the creation of efficient environmental sensors and biosensors as well as thermo-photovoltaic power generation systems. Here, we demonstrate such thermal emission control by manipulating photonic modes with photonic crystals as well as material absorption with quantum-well intersubband transitions. We show that the emission peak intensity for our device can be more than four times greater than that of a blackbody sample under the same input power and thermal management conditions due to an increase in the temperature compared to the blackbody reference, and the emission bandwidth and angular spread are narrowed by a factor of 30 and 8, respectively. These results indicate that the energy saved by thermal emission control can be recycled and concentrated to enhance the narrow peak emission intensity.
Glucose Starvation Inhibits Autophagy via Vacuolar Hydrolysis and Induces Plasma Membrane Internalization by Down-regulating Recycling*
Lang, Michael J.; Martinez-Marquez, Jorge Y.; Prosser, Derek C.; Ganser, Laura R.; Buelto, Destiney; Wendland, Beverly; Duncan, Mara C.
Cellular energy influences all aspects of cellular function. Although cells can adapt to a gradual reduction in energy, acute energy depletion poses a unique challenge. Because acute depletion hampers the transport of new energy sources into the cell, the cell must use endogenous substrates to replenish energy after acute depletion. In the yeast Saccharomyces cerevisiae, glucose starvation causes an acute depletion of intracellular energy that recovers during continued glucose starvation. However, how the cell replenishes energy during the early phase of glucose starvation is unknown. In this study, we investigated the role of pathways that deliver proteins and lipids to the vacuole during glucose starvation. We report that in response to glucose starvation, plasma membrane proteins are directed to the vacuole through reduced recycling at the endosomes. Furthermore, we found that vacuolar hydrolysis inhibits macroautophagy in a target of rapamycin complex 1-dependent manner. Accordingly, we found that endocytosis and hydrolysis are required for survival in glucose starvation, whereas macroautophagy is dispensable. Together, these results suggest that hydrolysis of components delivered to the vacuole independent of autophagy is the cell survival mechanism used by S. cerevisiae in response to glucose starvation. PMID:24753258
Waste to energy and recycling in Hempstead, Long Island
Aquino, J.T.
Faced with the limiting of landfill disposal by New York state law, a Long Island township opted for both waste-to-energy (WTE) and curbside recycling. Since then, the township and its WTE facility achieved results through state-of-the-art technology, creative agreements, and some compromise. The $360-million, 2,505-tpd WTE facility opened for commercial use in October 1989. Soon after, the town`s waste disposal fees dropped to a reported $79 per ton. The facility has since processed more than 5 million tons of solid waste with an energy value of about 5,200 Btus per pound, slightly above the 4,500- to 5,000-Btu average for a pound of generic MSW. The bond is being paid off through tipping fees and the sale of electricity to the Long Island Lighting Co. (LILCO). The facility is projected to save the town more than $500 million in disposal costs over the next 20 years. And, by using trash to generate electricity, the facility will save the equivalent of 53 million gallons of imported oil.
Effect of plasma surface treatment of recycled carbon fiber on carbon fiber-reinforced plastics (CFRP) interfacial properties
NASA Astrophysics Data System (ADS)
Lee, Hooseok; Ohsawa, Isamu; Takahashi, Jun
We studied the effects of plasma surface treatment of recycled carbon fiber on adhesion of the fiber to polymers after various treatment times. Conventional surface treatment methods have been attempted for recycled carbon fiber, but most require very long processing times, which may increase cost. Hence, in this study, plasma processing was performed for 0.5 s or less. Surface functionalization was quantified by X-ray photoelectron spectroscopy. O/C increased from approximately 11% to 25%. The micro-droplet test of adhesion properties and the mechanical properties of CFRP were also investigated.
Energy and materials use in the production and recycling of consumer-goods packaging
Gaines, L.L.
A comparison is made of the energy consumed annually in the United States to produce paper, glass, steel, aluminum, and plastic for consumer-goods packaging and types of energy used for production are examined. Energy saved through recycling and combustion for energy recovery also is considered. A maximum of 1.5 quad could be saved if this packaging material were recycled, and about 0.6 quad could be recovered if it were burned as part of municipal solid waste. Paper and plastic compete in several markets, including bags and milk containers: in almost all cases, the plastic container requires less energy to produce and recycle. However, the major energy input to paper manufacture is wood, rather than oil and natural gas. Glass bottles require less energy to produce than aluminum or steel cans. On the other hand, aluminum cans take less energy to recycle than bottles, and recycled aluminum cans are the least energy intensive of the single-serving beverage containers, except for refillable glass bottles that are reused several times. For family-sized beverage bottles, a plastic bottle uses less energy to make and to recycle than a glass bottle. In addition, plastic bottles are combustible. However, glass bottles could be made with no oil or natural gas input, and they can be reused.
Recyclable heparin and chitosan conjugated magnetic nanocomposites for selective removal of low-density lipoprotein from plasma.
Li, Jinghua; Hou, Yanhua; Chen, Xiuyong; Ding, Xingwei; Liu, Yun; Shen, Xinkun; Cai, Kaiyong
A new fabrication protocol is described to obtain heparin and chitosan conjugated magnetic nanocomposite as a blood purification material for removal of low-density lipoprotein (LDL) from blood plasma. The adsorbent could be easily separated with an external magnet for recyclable use since it had a magnetic core. The LDL level of plasma decreased by 67.3 % after hemoperfusion for 2 h. Moreover, the adsorbent could be recycled simply washing with NaCl solution. After eight cycles, the removal efficiency of the adsorbent was still above 50 %. The recyclable magnetic adsorbent had good blood compatibility due to the conjugation of heparin to the chitosan-coated magnetic nanocomposites. The fabricated magnetic adsorbent could be applied for LDL apheresis without side effects. PMID:24394982
Depolarization of D-T plasmas by recycling in material walls
Greenside, H.S.; Budny, R.V.; Post, D.E.
The feasibility of using polarized deuterium (D) and tritium (T) plasmas in fusion reactors may be seriously affected by recycling in material walls. Theoretical and experimental results are reviewed which show how the depolarization rates of absorbed D and T depend on first wall parameters such as the temperature, the bulk and surface diffusivities, the density of electronic states at the Fermi surface, the spectral density of microscopic fluctuating electric field gradients, and the concentration of paramagnetic impurities. Nuclear magnetic resonance (NMR) spectroscopy of hydrogenated and deuterated amorphous semiconductors suggests that low-Z nonmetallic materials may provide a satisfactory first wall or limiter coating under reactor conditions with characteristic depolarization times of several seconds. Experiments are proposed to test the consequences of our analysis.
Plasma Hypoxanthine-Guanine Phosphoribosyl Transferase Activity in Bottlenose Dolphins Contributes to Avoiding Accumulation of Non-recyclable Purines.
López-Cruz, Roberto I; Crocker, Daniel E; Gaxiola-Robles, Ramón; Bernal, Jaime A; Real-Valle, Roberto A; Lugo-Lugo, Orlando; Zenteno-Savín, Tania
Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzymes in purine metabolism were examined in plasma and red blood cells from bottlenose dolphins (Tursiops truncatus) and humans. Hypoxanthine and inosine monophosphate concentrations were higher in plasma from dolphins than humans. Plasma hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity in dolphins suggests an elevated purine recycling rate, and a mechanism for avoiding accumulation of non-recyclable purines (xanthine and uric acid). Red blood cell concentrations of hypoxanthine, adenosine diphosphate, ATP and guanosine triphosphate were lower in dolphins than in humans; adenosine monophosphate and nicotinamide adenine dinucleotide concentrations were higher in dolphins. HGPRT activity in red blood cells was higher in humans than in dolphins. The lower concentrations of purine catabolism and recycling by-products in plasma from dolphins could be beneficial in providing substrates for recovery of ATP depleted during diving or vigorous swimming. These results suggest that purine salvage in dolphins could be a mechanism for delivering nucleotide precursors to tissues with high ATP and guanosine triphosphate requirements. PMID:27375492
Plasma Hypoxanthine-Guanine Phosphoribosyl Transferase Activity in Bottlenose Dolphins Contributes to Avoiding Accumulation of Non-recyclable Purines
López-Cruz, Roberto I.; Crocker, Daniel E.; Gaxiola-Robles, Ramón; Bernal, Jaime A.; Real-Valle, Roberto A.; Lugo-Lugo, Orlando; Zenteno-Savín, Tania
Marine mammals are exposed to ischemia/reperfusion and hypoxia/reoxygenation during diving. During oxygen deprivation, adenosine triphosphate (ATP) breakdown implies purine metabolite accumulation, which in humans is associated with pathological conditions. Purine recycling in seals increases in response to prolonged fasting and ischemia. Concentrations of metabolites and activities of key enzymes in purine metabolism were examined in plasma and red blood cells from bottlenose dolphins (Tursiops truncatus) and humans. Hypoxanthine and inosine monophosphate concentrations were higher in plasma from dolphins than humans. Plasma hypoxanthine-guanine phosphoribosyl transferase (HGPRT) activity in dolphins suggests an elevated purine recycling rate, and a mechanism for avoiding accumulation of non-recyclable purines (xanthine and uric acid). Red blood cell concentrations of hypoxanthine, adenosine diphosphate, ATP and guanosine triphosphate were lower in dolphins than in humans; adenosine monophosphate and nicotinamide adenine dinucleotide concentrations were higher in dolphins. HGPRT activity in red blood cells was higher in humans than in dolphins. The lower concentrations of purine catabolism and recycling by-products in plasma from dolphins could be beneficial in providing substrates for recovery of ATP depleted during diving or vigorous swimming. These results suggest that purine salvage in dolphins could be a mechanism for delivering nucleotide precursors to tissues with high ATP and guanosine triphosphate requirements. PMID:27375492
Saving Energy and Developing Creativity in Recycling Clothing.
ERIC Educational Resources Information Center
Sohn, Marjorie
To help counter the "throw-away society" the author says that home economists should include extending use of or recycling clothing in their classes or adult programs. She offers guidelines for altering garments, figuring costs, and determining what methods might be used. (MF)
Energy conservation and CO2 emission reductions due to recycling in Brazil.
Pimenteira, C A P; Pereira, A S; Oliveira, L B; Rosa, L P; Reis, M M; Henriques, R M
The present paper aims to make the energy saving potential provided by waste recycling in Brazil evident by pointing out more specifically the benefits regarding climate change mitigation. In this case, based on the energy saved due to the recycling process of an exogenous amount of waste, we have built two scenarios in order to show the potential for indirectly avoiding CO2 emissions in the country as a result of the recycling process. According to the scenario, 1 Mt and 3.5 Mt of CO2, respectively, would be avoided per year due to solid waste recycling. The international context for greenhouse gas emissions reduction, such as the United Nations Framework Convention on Climate Change and its Kyoto Protocol has been taken into account. PMID:15504666
Automotive recycling in the United States : energy conservation and enviromental benefits.
Pomykala, J. A; Jody, B. J.; Daniels, E. J.; Spangenberger, J. S.; Energy Systems
The production and use of polymers has been growing and that trend is expected to continue. Likewise, the production of metals from ores is on the rise because of increasing demand. Recycling polymers and residual metals can result in significant energy savings and environmental benefits including a reduction in CO2 emissions. This article describes recycling options for the polymers and metals in end-of-life vehicles.
Automotive recycling in the United States: Energy conservation and environmental benefits
NASA Astrophysics Data System (ADS)
Pomykala, J. A.; Jody, B. J.; Daniels, E. J.; Spangenberger, J. S.
The production and use of polymers has been growing and that trend is expected to continue. Likewise, the production of metals from ores is on the rise because of increasing demand. Recycling polymers and residual metals can result in significant energy savings and environmental benefits including a reduction in CO2 emissions. This article describes recycling options for the polymers and metals in end-of-life vehicles.
Rabenosyn-5 and EHD1 Interact and Sequentially Regulate Protein Recycling to the Plasma MembraneD⃞
Naslavsky, Naava; Boehm, Markus; Backlund, Peter S.; Caplan, Steve
EHD1 has been implicated in the recycling of internalized proteins to the plasma membrane. However, the mechanism by which EHD1 mediates recycling and its relationship to Rab-family–controlled events has yet to be established. To investigate further the mode of EHD1 action, we sought to identify novel interacting partners. GST-EHD1 was used as bait to isolate a ∼120-kDa species from bovine and murine brain cytosol, which was identified by mass spectrometry as the divalent Rab4/Rab5 effector Rabenosyn-5. We mapped the sites of interaction to the EH domain of EHD1, and the first two of five NPF motifs of Rabenosyn-5. Immunofluorescence microscopy studies revealed that EHD1 and Rabenosyn-5 partially colocalize to vesicular and tubular structures in vivo. To address the functional roles of EHD1 and Rabenosyn-5, we first demonstrated that RNA interference (RNAi) dramatically reduced the level of expression of each protein, either individually or in combination. Depletion of either EHD1 or Rabenosyn-5 delayed the recycling of transferrin and major histocompatibility complex class I to the plasma membrane. However, whereas depletion of EHD1 caused the accumulation of internalized cargo in a compact juxtanuclear compartment, Rabenosyn-5-RNAi caused its retention within a dispersed peripheral compartment. Simultaneous RNAi depletion of both proteins resulted in a similar phenotype to that observed with Rabenosyn-5-RNAi alone, suggesting that Rabenosyn-5 acts before EHD1 in the regulation of endocytic recycling. Our studies suggest that Rabenosyn-5 and EHD1 act sequentially in the transport of proteins from early endosomes to the endosomal recycling compartment and back to the plasma membrane. PMID:15020713
Energy Measurement in a Plasma Wakefield Accelerator
Ischebeck, R
In the E-167 plasma wakefield acceleration experiment, electrons with an initial energy of 42GeV are accelerated in a meter-scale lithium plasma. Particles are leaving plasma with a large energy spread. To determine the spectrum of the accelerated particles, a two-plane spectrometer has been set up.
Materials development and field demonstration of high-recycled-content concrete for energy-efficient building construction
Ostowari, Ken; Nosson, Ali
The project developed high-recycled-content concrete material with balanced structural and thermal attributes for use in energy-efficient building construction. Recycled plastics, tire, wool, steel and concrete were used as replacement for coarse aggregates in concrete and masonry production. With recycled materials the specific heat and thermal conductivity of concrete could be tailored to enhance the energy-efficiency of concrete buildings. A comprehensive field project was implemented which confirmed the benefits of high-recycled-content concrete for energy-efficient building construction.
Low recycling and high power density handling physics in the Current Drive Experiment-Upgrade with lithium plasma-facing components
Kaita, R.; Majeski, R.; Gray, T.; Kugel, H.; Mansfield, D.; Spaleta, J.; Timberlake, J.; Zakharov, L.; Doerner, R.; Lynch, T.; Maingi, R.; Soukhanovskii, V.
The Current Drive Experiment-Upgrade [T. Munsat, P. C. Efthimion, B. Jones, R. Kaita, R. Majeski, D. Stutman, and G. Taylor, Phys. Plasmas 9, 480 (2002)] spherical tokamak research program has focused on lithium as a large area plasma-facing component (PFC). The energy confinement times showed a sixfold or more improvement over discharges without lithium PFCs. This was an increase of up to a factor of 3 over ITER98P(y,1) scaling [ITER Physics Basis Editors, Nucl. Fusion 39, 2137 (1999)], and reflects the largest enhancement in confinement ever seen in Ohmic plasmas. Recycling coefficients of 0.3 or below were achieved, and they are the lowest to date in magnetically confined plasmas. The effectiveness of liquid lithium in redistributing heat loads at extremely high power densities was demonstrated with an electron beam, which was used to generate lithium coatings. When directed to a lithium reservoir, evaporation occurred only after the entire volume of lithium was raised to the evaporation temperature. The ability to dissipate a beam power density of about 60 MW/m{sup 2} could have significant consequences for PFCs in burning plasma devices.
Energy and environmental impacts of electric vehicle battery production and recycling
Gaines, L.; Singh, M.
Electric vehicle batteries use energy and generate environmental residuals when they are produced and recycled. This study estimates, for 4 selected battery types (advanced lead-acid, sodium-sulfur, nickel-cadmium, and nickel-metal hydride), the impacts of production and recycling of the materials used in electric vehicle batteries. These impacts are compared, with special attention to the locations of the emissions. It is found that the choice among batteries for electric vehicles involves tradeoffs among impacts. For example, although the nickel-cadmium and nickel-metal hydride batteries are similar, energy requirements for production of the cadmium electrodes may be higher than those for the metal hydride electrodes, but the latter may be more difficult to recycle.
Mandated recycling rates: Impacts on energy consumption and municipal waste volume
Gaines, L.L.; Stodolsky, F.
In 1992, Congress sought to rewrite its comprehensive solid waste legislation the Resource Conservation and Recovery Act (RCRA). Commodity-specific recycling rates were proposed for consumer-goods packaging, materials and newsprint. In this paper, we compare the impacts on energy, materials use, and landfill volume of recycling at those rates to the impacts associated with alternative methods of disposition to determine, the optimal method for each material. Alternative paths for material disposition include reuse, recycling to the same product, recycling to a lower-valued product, combustion for energy recovery, incineration without energy recovery, and landfilling. The recovery rates considered during RCRA reauthorization are summarized. Combustion was specifically excluded by Congress to meet recovery goals. This exclusion is probably based on the idea that combustion is a form of disposal and therefore wastes resources and has negative environmental effects. Our paper does not make that assumption. A report by Gaines and Stodolsky, from which this paper is derived, offers a more complete discussion of energy and S impacts.
The Wheelabrator Falls story -- Integrated recycling, highly efficient energy recovery: An update two years later
Felago, R.T.; Anderson, R.L.; Scanlon, P.J.
Wheelabrator Environmental Systems Inc., based in Hampton, New Hampshire, has developed America`s first privately initiated, totally integrated Materials Recovery Facility (MRF) with a commercial trash-to-energy facility in Falls Township, Bucks County, Pennsylvania. The MRF is successfully recovering and marketing a variety of recycled products, while demonstrating that waste-to-energy and recycling are compatible and can be successfully integrated at a single site. The energy recovery plant and the MRF have completed one year of operation, giving adequate time to evaluate the impact of project innovations. These innovations will have a significant impact on how future projects, including waste-to-energy, wastewater and biosolids processing, will be developed. The energy recovery facility is capable of processing 1,600 tons per day of municipal solid waste from the Bucks County area.
Modeling of particle and energy transport in the edge plasma of Alcator C-Mod
NASA Astrophysics Data System (ADS)
Umansky, M. V.; Krasheninnikov, S. I.; LaBombard, B.; Lipschultz, B.; Terry, J. L.
In the present study recycling and transport in the edge plasma of Alcator C-Mod [I. H. Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] is modeled and analyzed with the multi-fluid code UEDGE [T. D. Rognlien et al., J. Nucl. Mater. 196-198, 347 (1992)]. Matching the experimental plasma density profiles in the scrape-off layer (SOL) requires a spatially dependent effective anomalous diffusion coefficient D⊥ growing rapidly towards the wall. The midplane pressure of neutral gas, Pmid, is a key parameter that reflects the magnitude of anomalous transport of plasma from the core. Recycling of plasma on the main chamber wall appears to be quite significant, especially in the case of high Pmid˜0.3 mTorr when the main wall provides ˜70% of recycling neutrals in the main chamber. In the upper SOL (well above the x point) draining of particles by the poloidal flow is weak and thus the particle balance is predominantly radial. For the radial heat transport it is found that energy flux carried by radial plasma convection and by charge-exchange (CX) neutrals is quite significant in SOL. In the high Pmid case, heat conduction by CX neutrals along with radial heat convection by plasma carries most of the power flux (˜75%) across the last closed flux surface. Even in the low Pmid case, heat conduction by CX neutrals dominates the radial heat flux far out in the SOL.
Assessing recycling versus incineration of key materials in municipal waste: The importance of efficient energy recovery and transport distances
Merrild, Hanna; Larsen, Anna W.; Christensen, Thomas H.
Highlights: Black-Right-Pointing-Pointer We model the environmental impact of recycling and incineration of household waste. Black-Right-Pointing-Pointer Recycling of paper, glass, steel and aluminium is better than incineration. Black-Right-Pointing-Pointer Recycling and incineration of cardboard and plastic can be equally good alternatives. Black-Right-Pointing-Pointer Recyclables can be transported long distances and still have environmental benefits. Black-Right-Pointing-Pointer Paper has a higher environmental benefit than recyclables found in smaller amounts. - Abstract: Recycling of materials from municipal solid waste is commonly considered to be superior to any other waste treatment alternative. For the material fractions with a significant energy content this might not be the case if the treatment alternative is a waste-to-energy plant with high energy recovery rates. The environmental impacts from recycling and from incineration of six material fractions in household waste have been compared through life cycle assessment assuming high-performance technologies for material recycling as well as for waste incineration. The results showed that there are environmental benefits when recycling paper, glass, steel and aluminium instead of incinerating it. For cardboard and plastic the results were more unclear, depending on the level of energy recovery at the incineration plant, the system boundaries chosen and which impact category was in focus. Further, the environmental impact potentials from collection, pre-treatment and transport was compared to the environmental benefit from recycling and this showed that with the right means of transport, recyclables can in most cases be transported long distances. However, the results also showed that recycling of some of the material fractions can only contribute marginally in improving the overall waste management system taking into consideration their limited content in average Danish household waste.
Greening the Department of Energy through waste prevention, recycling, and Federal acquisition. Strategic plan to implement Executive Order 13101
This Plan provides strategies and milestones to implement Executive Order 13101, Greening the Government Through Waste Prevention, Recycling, and Federal Acquisition, and to achieve the new Secretarial goals for 2005 and 2010. It serves as the principal Secretarial guidance to Department of Energy (DOE) Headquarters, Field Offices, and laboratory and contractor staff to improve sanitary waste prevention, recycling, and the purchase and use of recycled content and environmentally preferable products and services in the DOE.
Responsible, Renewable, Recyclable: An Energy Management Strategy for Modern Accelerators
NASA Astrophysics Data System (ADS)
Jansson, Andreas
The European Spallation Source (ESS), which will be built in the south of Sweden, uses a 5 MW proton beam from a 2.5 GeV superconducting linac. When completed, it will be the world's most powerful cold neutron source. The ESS has set the objective to be carbon neutral and as energy efficient as possible. This will be achieved in part by energy saving measures, but also by investing in renewable energy sources and re-using the excess heat through the local district heating system. This talk will give an overview of the ESS project and its energy management strategy.
Enhancing biomass energy yield from pilot-scale high rate algal ponds with recycling.
Park, J B K; Craggs, R J; Shilton, A N
This paper investigates the effect of recycling on biomass energy yield in High Rate Algal Ponds (HRAPs). Two 8 m(3) pilot-scale HRAPs treating primary settled sewage were operated in parallel and monitored over a 2-year period. Volatile suspended solids were measured from both HRAPs and their gravity settlers to determine biomass productivity and harvest efficiency. The energy content of the biomass was also measured. Multiplying biomass productivity and harvest efficiency gives the 'harvestable biomass productivity' and multiplying this by the energy content defines the actual 'biomass energy yield'. In Year 1, algal recycling was implemented in one of the ponds (HRAPr) and improved harvestable biomass productivity by 58% compared with the control (HRAPc) without recycling (HRAPr: 9.2 g/m(2)/d; HRAPc: 5.8 g/m(2)/d). The energy content of the biomass grown in HRAPr, which was dominated by Pediastrun boryanum, was 25% higher than the control HRAPc which contained a mixed culture of 4-5 different algae (HRAPr: 21.5 kJ/g; HRAPc: 18.6 kJ/g). In Year 2, HRAPc was then seeded with the biomass harvested from the P. boryanum dominated HRAPr. This had the effect of shifting algal dominance from 89% Dictyosphaerium sp. (which is poorly-settleable) to over 90% P. boryanum in 5 months. Operation of this pond was then switched to recycling its own harvested biomass, which maintained P. boryanum dominance for the rest of Year 2. This result confirms, for the first time in the literature, that species control is possible for similarly sized co-occurring algal colonies in outdoor HRAP by algal recycling. With regard to the overall improvement in biomass energy yield, which is a critical parameter in the context of algal cultivation for biofuels, the combined improvements that recycling triggered in biomass productivity, harvest efficiency and energy content enhanced the harvested biomass energy yield by 66% (HRAPr: 195 kJ/m(2)/day; HRAPc: 118 kJ/m(2)/day). PMID:23764593
An energy-efficient, adiabatic electrode stimulator with inductive energy recycling and feedback current regulation.
Arfin, Scott K; Sarpeshkar, Rahul
In this paper, we present a novel energy-efficient electrode stimulator. Our stimulator uses inductive storage and recycling of energy in a dynamic power supply. This supply drives an electrode in an adiabatic fashion such that energy consumption is minimized. It also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The dynamic power supply allows efficient transfer of energy both to and from the electrode and is based on a DC-DC converter topology that we use in a bidirectional fashion in forward-buck or reverse-boost modes. In an exemplary electrode implementation intended for neural stimulation, we show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard .35 μm CMOS process. This stimulator achieves a 2x-3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply. We perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. This theoretical analysis reveals that further improvements in energy efficiency may be achievable with better implementations in the future. Our electrode stimulator could be widely useful for neural, cardiac, retinal, cochlear, muscular and other biomedical implants where low power operation is important. PMID:23852740
U.S. Department of Energy National Center of Excellence for Metals Recycle
Adams, V.; Bennett, M.; Bishop, L.
The US Department of Energy (DOE) National Center of Excellence for Metals Recycle has recently been established. The vision of this new program is to develop a DOE culture that promotes pollution prevention by considering the recycle and reuse of metal as the first and primary disposition option and burial as a last option. The Center of Excellence takes the approach that unrestricted release of metal is the first priority because it is the most cost-effective disposition pathway. Where this is not appropriate, restricted release, beneficial reuse, and stockpile of ingots are considered. Current recycling activities include the sale of 40,000 tons of scrap metal from the East Tennessee Technology Park (formerly K-25 Plant) K-770 scrap yard, K-1064 surplus equipment and machinery, 7,000 PCB-contaminated drums, 12,000 tons of metal from the Y-l2 scrap yard, and 1,000 metal pallets. In addition, the Center of Excellence is developing a toolbox for project teams that will contain a number of specific tools to facilitate metals recycle. This Internet-based toolbox will include primers, computer programs, and case studies designed to help sites to perform life cycle analysis, perform ALARA (As Low As is Reasonably Achievable) analysis for radiation exposures, provide pollution prevention information and documentation, and produce independent government estimates. The use of these tools is described for two current activities: disposition of scrap metal in the Y-12 scrapyard, and disposition of PCB-contaminated drums.
High Energy Plasma Space Propulsion
NASA Technical Reports Server (NTRS)
Wu, S. T.
In order to meet NASA's challenge on advanced concept activity in the propulsion area, we initiated a new program entitled "High Energy Plasma Space Propulsion Studies" within the current cooperative agreement in 1998. The goals of this work are to gain further understanding of the engine of the AIMStar spacecraft, a concept which was developed at Penn State University, and to develop a prototype concept for the engine. The AIMStar engine concept was developed at Penn State University several years ago as a hybrid between antimatter and fusion technologies. Because of limited amounts of antimatter available, and concurrently the demonstrated ability for antiprotons to efficiently ignite nuclear fusion reactions, it was felt that this was a very good match. Investigations have been made concerning the performance of the reaction trap. This is a small Penning-like electromagnetic trap, which is used to simultaneously confine antiprotons and fusion fuels. Small DHe3 or DT droplets, containing a few percent molar of a fissile material, are injected into the trap, filled with antiprotons. We have found that it is important to separate the antiprotons into two adjacent wells, to inject he droplet between them and to simultaneously bring the antiprotons to the center of the trap, surrounding the droplet. Our previous concept had the droplet falling onto one cloud of antiprotons. This proved to be inefficient, as the droplet tended to evaporate away from the cloud as it interacted on its surface.
Biomass recycle as a means to improve the energy efficiency of CELSS algal culture systems
NASA Technical Reports Server (NTRS)
Radmer, R.; Cox, J.; Lieberman, D.; Behrens, P.; Arnett, K.
Algal cultures can be very rapid and efficient means to generate biomass and regenerate the atmosphere for closed environmental life support systems. However, as in the case of most higher plants, a significant fraction of the biomass produced by most algae cannot be directly converted to a useful food product by standard food technology procedures. This waste biomass will serve as an energy drain on the overall system unless it can be efficiently recycled without a significant loss of its energy content. Experiments are reported in which cultures of the alga Scenedesmus obliquus were grown in the light and at the expense of an added carbon source, which either replaced or supplemented the actinic light. As part of these experiments, hydrolyzed waste biomass from these same algae were tested to determine whether the algae themselves could be made part of the biological recycling process. Results indicate that hydrolyzed algal (and plant) biomass can serve as carbon and energy sources for the growth of these algae, suggesting that the efficiency of the closed system could be significantly improved using this recycling process.
Waste recycling primary source of energy in deep ocean
NASA Astrophysics Data System (ADS)
Schultz, Colin
In the dark reaches of the deep ocean, far from the photosynthesizing plants and plankton that fuel life in the surface waters, ecosystems survive on chemical energy. Decades of research on the life that clusters around deep-sea hydrothermal vents has hinted at the importance of light-free food webs, but a recent analysis by Middelburg suggests that another system—waste recycling—could be the dominant pillar of life on the abyssal plains. The realization was a result of the author's attempt to calculate the importance of chemoautotrophy to the carbon cycles of different ocean regions. levels increase rates of denitrification and methanogenesis, thus increasing gas production rates. The authors also found that methane bubbles surpass diffused nitrous oxide in terms of global warming potential, which they suggest could warrant a rethinking of the importance of streams and rivers to global warming. (Journal of Geophysical Research-Biogeosciences, doi:10.1029/2011JG001656, 2011)
Improving Energy Efficiency and Enabling Water Recycle in Biorefineries Using Bioelectrochemical Cells.
Borole, Abhijeet P
Improving biofuel yield and water reuse are two important issues in further development of biorefineries. The total energy content of liquid fuels (including ethanol and hydrocarbon) produced from cellulosic biomass via biochemical or hybrid bio-thermochemical routes can vary from 49% to 70% of the biomass entering the biorefinery, on an energy basis. Use of boiler for combustion of residual organics and lignin results in significant energy and water losses. An alternate process to improve energy recovery from the residual organic streams is via use of bioelectrochemical systems such as microbial fuel cells (MFCs) microbial electrolysis cells (MECs). The potential advantages of this alternative scheme in a biorefinery include minimization of heat loss and generation of a higher value product, hydrogen. The need for 5-15 gallons of water per gallon of ethanol can be reduced significantly via recycle of water after MEC treatment. Removal of inhibitory byproducts such as furans, phenolics and acetate in MFC/MECs to generate energy, thus, has dual advantages including improvements in energy efficiency and ability to recycle water. Conversion of the sugar- and lignin- degradation products to hydrogen is synergistic with biorefinery hydrogen requirements for upgrading F-T liquids and other byproducts to high-octane fuels and/or high value products. Some of these products include sorbitol, succinic acid, furan and levulinate derivatives, glycols, polyols, 1,4-butenadiol, phenolics polymers, etc. Potential process alternatives utilizing MECs in biorefineries capable of improving energy efficiency by up to 30% are discussed.
Tailored ion energy distributions on plasma electrodes
Economou, Demetre J.
As microelectronic device features continue to shrink approaching atomic dimensions, control of the ion energy distribution on the substrate during plasma etching and deposition becomes increasingly critical. The ion energy should be high enough to drive ion-assisted etching, but not too high to cause substrate damage or loss of selectivity. In many cases, a nearly monoenergetic ion energy distribution (IED) is desired to achieve highly selective etching. In this work, the author briefly reviews: (1) the fundamentals of development of the ion energy distribution in the sheath and (2) methods to control the IED on plasma electrodes. Such methods include the application of "tailored" voltage waveforms on an electrode in continuous wave plasmas, or the application of synchronous bias on a "boundary electrode" during a specified time window in the afterglow of pulsed plasmas.
Equilibrium fluctuation energy of gyrokinetic plasma
Krommes, J.A.; Lee, W.W.; Oberman, C.
The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result
Low energy stable plasma calibration facility
NASA Astrophysics Data System (ADS)
Frederick-Frost, K. M.; Lynch, K. A.
We have designed and fabricated a low energy plasma calibration facility for testing and calibration of rocket-borne charged-particle detectors and for the investigation of plasma sheath formation in an environment with ionospheric plasma energies, densities, and Debye lengths. We describe the vacuum system and associated plasma source, which was modified from a Naval Research Laboratory design [Bowles et al. Rev. Sci. Instrum. 67, 455 (1996)]. Mechanical and electrical modifications to this cylindrical microwave resonant source are outlined together with a different method of operating the magnetron that achieves a stable discharge. This facility produces unmagnetized plasmas with densities from 1×103/cm3to6×105/cm3, electron temperatures from 0.1to1.7eV, and plasma potentials from 0.5to8V depending on varying input microwave power and neutral gas flow. For the range of input microwave power explored (350-600W), the energy density of the plasma remains constant because of an inverse relationship between density and temperature. This relationship allows a wide range of Debye lengths (0.3-8.4cm) to be investigated, which is ideal for simulating the ionospheric plasma sheaths we explore.
Energy conserving continuum algorithms for kinetic & gyrokinetic simulations of plasmas
NASA Astrophysics Data System (ADS)
Hakim, A.; Hammett, G. W.; Shi, E.; Stoltzfus-Dueck, T.
We present high-order, energy conserving, continuum algorithms for the solution of gyrokinetic equations for use in edge turbulence simulations. The distribution function is evolved with a discontinuous Galerkin scheme, while the fields are evolved with a continuous finite-element method. These algorithms work for a general, possibly non-canonical, Poisson bracket operator and conserve energy exactly. Benchmark simulations with ETG turbulence in 3X/2V are shown, as well as initial applications of the algorithms to turbulence in a simplified SOL geometry. Sheath boundary conditions with recycling and secondary electron emission are implemented, and a Lenard-Bernstein collision operator is included. Extension of these algorithms to full Vlasov-Maxwell equations are presented. It is shown that with a particular choice of numerical fluxes the total (particle+field) energy is conserved. Algorithms are implemented in a flexible and open-source framework, Gkeyll, which also includes fluid models, allowing potential hybrid simulations of various plasma problems. Supported by the Max-Planck/Princeton Center for Plasma Physics, and DOE Contract DE-AC02-09CH11466.
Characterisation of the deuterium recycling at the W divertor target plates in JET during steady-state plasma conditions and ELMs
NASA Astrophysics Data System (ADS)
Brezinsek, S.; Wiesen, S.; Harting, D.; Guillemaut, C.; Webster, A. J.; Heinola, K.; Meigs, A. G.; Rack, M.; Gao, Y.; Sergienko, G.; Philipps, V.; Stamp, M. F.; Jachmich, S.; Contributors, JET
Experiments in the JET tokamak equipped with the ITER-like wall (ILW) revealed that the inner and outer target plate at the location of the strike points represent after one year of operation intact tungsten (W) surfaces without any beryllium (Be) surface coverage. The dynamics of near-surface retention, implantation, desorption and recycling of deuterium (D) in the divertor of plasma discharges are determined by W target plates. As the W plasma-facing components (PFCs) are not actively cooled, the surface temperature (T surface) is increasing with plasma exposure, varying the balance between these processes in addition to the impinging deuteron fluxes and energies. The dynamic behaviour on a slow time scale of seconds was quantified in a series of identical L-mode discharges (JET Pulse Number (JPN) \\# 81938-73) by intra-shot gas analysis providing the reduction of deuterium retention in W PFCs by 1/3 at a base temperature (T base) range at the outer target plate between 65 °C and 150 °C equivalent to a T surface span of 150 °C and 420 °C. The associated recycling and molecular D desorption during the discharge varies only at lowest temperatures moderately, whereas desorption between discharges rises significantly with increasing T base. The retention measurements represent the sum of inner and outer divertor interaction at comparable T surface. The dynamic behaviour on a fast time scale of ms was studied in a series of identical H-mode discharges (JPN \\#83623-83974) and coherent edge-localized mode (ELM) averaging. High energetic ELMs of about 3 keV are impacting on the W PFCs with fluxes of 3× {10}23 {{{D}}}+ {{{s}}}-1{{{m}}}-2 which is about four times higher than inter-ELM ion fluxes with an impact energy of about E im = 200 eV. This intra-ELM ion flux is associated with a high heat flux of about 60 MW m-2 to the outer target plate which causes T surface rise by Δ T = 100 K per ELM covering finally the range between 160 °C and 1400 °C during the flat
Hydrogen recycling study by Balmer lines emissions in linear plasma machine TPE
NASA Astrophysics Data System (ADS)
Shimada, K.; Tanabe, T.; Causey, R.; Venhaus, T.; Okuno, K.
We have investigated the influence of target materials and temperatures on Balmer series emission in a linear plasma apparatus, Tritium Plasma Experiment (TPE). The intensities of the Balmer series emission in front of the target were higher for heavier mass target and also for lower target temperature, showing rather linear relationship between the emission intensity and hydrogen reflection coefficient. For exothermic hydrogen occluders of Ti and Ta, the intensity ratio of Dβ/ Dα increased with the target temperature markedly, whereas the intensity ratio stayed rather constant for endothermic hydrogen occluders of Ni, Cu and W. This is a clear demonstration that the target materials and temperatures modify the boundary plasma. In addition the intensity ratio Dβ/Dα is not simply a function of plasma temperature but has clear target temperature dependence.
Energy-Recycling Semi-Active Vibration Suppression Experiment of a Truss with Piezoelectric Transducer
NASA Astrophysics Data System (ADS)
Makihara, K.
inherent performance in damping is enhanced. Several semi-active vibration suppression approaches have been proposed based on variable-stiffness members, variable-friction devices, or variable-viscosity dampers, and the performance of each of these systems has been studied. The semi-active approach exploits passive energy-dissipation mechanisms, and supplies the system with no additional energy. Semi-active vibration suppression thus ensures that the system is always stable. This is its advantage. However, its performance in vibration suppression is usually inferior to active vibration suppression. have proposed collection of the energy taken from a vibrating system in suppressing its vibration. Using the collected energy to more quickly suppress the vibration is an attractive possibility. Additional energy is still not supplied to the system, and the vibration energy is finally dissipated. Therefore, this is a kind of semi-active approach, and retains the quality of that the system with it is always stable. method of energy-recycling semi-active vibration suppression is described and its performance is demonstrated by an experiment. A five bay truss beam with a piezoelectric transducer was used, and a simple electric circuit with switches was connected to the transducers. Then the switches were controlled by a processor so that the vibration was quickly suppressed by exploiting the collected electric energy. The results of the experiment demonstrated that the performance in vibration suppression of energy-recycling semi-active vibration suppression with actual hardware is much better than that of a traditional semi-active control. The effects of some non-ideal characteristics of real hardware on the performance in vibration suppression are also investigated.
Josephson, V.; Hammel, J.E.
An apparatus is presenied for producing neutrons as a result of collisions between ions in high temperature plasmas. The invention resides in the particular arrangement of ihe device whereby ihe magneiic and electric fields are made to cross at substantially right angles in several places along a torus shaped containment vessel. A plasma of deuterium gas is generated in the vessel under the electric fields and is "trapped" in any one of the "crossed field" regions to produce a release of energy.
Impact of recycling on cradle-to-gate energy consumption and greenhouse gas emissions of automotive lithium-ion batteries.
Dunn, Jennifer B; Gaines, Linda; Sullivan, John; Wang, Michael Q
This paper addresses the environmental burdens (energy consumption and air emissions, including greenhouse gases, GHGs) of the material production, assembly, and recycling of automotive lithium-ion batteries in hybrid electric, plug-in hybrid electric, and battery electric vehicles (BEV) that use LiMn(2)O(4) cathode material. In this analysis, we calculated the energy consumed and air emissions generated when recovering LiMn(2)O(4), aluminum, and copper in three recycling processes (hydrometallurgical, intermediate physical, and direct physical recycling) and examined the effect(s) of closed-loop recycling on environmental impacts of battery production. We aimed to develop a U.S.-specific analysis of lithium-ion battery production and in particular sought to resolve literature discrepancies concerning energy consumed during battery assembly. Our analysis takes a process-level (versus a top-down) approach. For a battery used in a BEV, we estimated cradle-to-gate energy and GHG emissions of 75 MJ/kg battery and 5.1 kg CO(2)e/kg battery, respectively. Battery assembly consumes only 6% of this total energy. These results are significantly less than reported in studies that take a top-down approach. We further estimate that direct physical recycling of LiMn(2)O(4), aluminum, and copper in a closed-loop scenario can reduce energy consumption during material production by up to 48%. PMID:23075406
Simulation of High Energy Density Laboratory Plasmas
NASA Astrophysics Data System (ADS)
Guzik, Joyce
High Energy Density plasmas are found in astrophysical environments, have been generated in past underground nuclear tests, and can be created in the laboratory by, e.g. laser or pulsed power experiments. These experiments can be used to validate simulation capabilities that are being developed to advance our understanding of plasma physics, and to develop predictive capabilities for HED plasma applications such as fusion energy. In this talk we will briefly introduce the subject of simulating HED plasmas using radiation hydrodynamics codes. We will give examples of simple test problems, showing how a problem is approached, including geometry specifications, simplifying assumptions, zoning, initial and boundary conditions, basic data on opacities and EOS, and illustrate sensitivities of results to variations. We will also show highlights of work at Los Alamos to validate codes, provide basic data, and develop applications, for example: 1) studying phenomena such as Rayleigh-Taylor and Richtmeyer-Meshkov instabilities, ablation, and supersonic jets at the Omega laser in Rochester and the Sandia Z Machine; 2) quantum molecular dynamics simulations which have recently led to a semi-classical, particle-particle particle-mesh code that allows ultra-fast simulations involving tens of thousands of particles to calculate properties of hot dense plasmas; 3) efforts to experimentally demonstrate the physics basis for magnetized target fusion (MTF), a potentially low cost path to fusion, intermediate in plasma regime between magnetic and inertial fusion energy.
Preparation of Crumpled Graphite Oxide from Recycled Graphite Using Plasma Electrolysis and Its Application for Adsorption of Cadmium in Aqueous Environment
NASA Astrophysics Data System (ADS)
Hong, Phan Ngoc; Tuoi, Tran Thi; Ngan, Nguyen Thi Kim; Trang, Bui Thi; Minh, Phan Ngoc; Lam, Tran Dai; Hanh, Nguyen Thi; Van Thanh, Dang
Household battery waste is considered hazardous and needs to be collected, managed, and recycled appropriately. In this study, using a plasma electrolysis method, we recycled graphite electrodes of exhausted dry batteries to prepare crumpled graphite oxide (CGO). Scanning electron microscopy revealed that the CGO possessed spherical morphology with average dimensions of 0.5 μm to 5 μm. The as-prepared CGO was then applied to absorb cadmium in aqueous environment. The results showed that CGO appears to be a promising adsorbent for removal of toxic waste from polluted water.
Combine waste-to-energy, recycling with fluid-bed boiler
Murphy, M.L.
An effective long-term solid-waste management program will soon be a reality for Bladen, Cumberland, and Hoke counties, North Carolina. The key element of the program is a 600-ton/day waste-to-energy (WTE) facility, scheduled to begin commercial operation later this year. The BCH Energy project, which gets its name from the initials of the three counties it serves, will become the first fluidized-bed boiler in the US designed to be fueled solely by refuse-derived fuel (RDF). As such, it provides an innovative and efficient approach to solid-waste management in several ways: (1) maximimizes community participation in a recovery and recycling effort; (2) maximizes additional waste handling and hauling efforts; (3) significantly reducing waste flow into landfill; (4) eliminating use of fossil fuel for a nearby chemical plant`s energy load; and (5) substantially improves air quality through use of the latest combustoin and emissions control technology.
Tritium recycling and inventory in eroded debris of plasma-facing materials
Hassanein, A.
Damage to plasma-facing components (PFCs) and structural materials due to loss of plasma confinement in magnetic fusion reactors remains one of the most serious concerns for safe, successful, and reliable tokamak operation. High erosion losses due to surface vaporization, spallation, and melt-layer splashing are expected during such an event. The eroded debris and dust of the PFCs, including trapped tritium, will be contained on the walls or within the reactor chamber therefore, they can significantly influence plasma behavior and tritium inventory during subsequent operations. Tritium containment and behavior in PFCS and in the dust and debris is an important factor in evaluating and choosing the ideal plasma-facing materials (PFMs). Tritium buildup and release in the debris of candidate materials is influenced by the effect of material porosity on diffusion and retention processes. These processes have strong nonlinear behavior due to temperature, volubility, and existing trap sites. A realistic model must therefore account for the nonlinear and multidimensional effects of tritium diffusion in the porous-redeposited and neutron-irradiated materials. A tritium-transport computer model, TRAPS (Tritium Accumulation in Porous Structure), was developed and used to evaluate and predict the kinetics of tritium transport in porous media. This model is coupled with the TRICS (Tritium In Compound Systems) code that was developed to study the effect of surface erosion during normal and abnormal operations on tritium behavior in PFCS.
Vacuum energy of a spherical plasma shell
Bordag, M.; Khusnutdinov, N.
We consider the vacuum energy of the electromagnetic field interacting with a spherical plasma shell together with a model for the classical motion of the shell. We calculate the heat kernel coefficients, especially that for the TM mode, and carry out the renormalization by redefining the parameters of the classical model. It turns out that this is possible and results in a model which, in the limit of the plasma shell becoming an ideal conductor, reproduces the vacuum energy found by Boyer in 1968.
Miniaturized Energy Spectrometer for Space Plasma Measurements
NASA Astrophysics Data System (ADS)
Goes de Lima, Raphaela; Scime, Earl; Keesee, Amy; Lusk, Greg
Taking advantage of technological developments in lithographic fabrication techniques over the past two decades, we have designed an ultra-compact plasma spectrometer that requires only low voltage power supplies, no microchannel plates, and has a high aperture area to instrument area ratio. The designed target is for ions in the 3- 20 keV range with a highly directional field of view. In addition to reducing mass, size, and voltage requirements, the new design will revolutionize the manufacturing process of plasma spectrometers, enabling large quantities of identical instruments to be manufactured at low individual unit cost. Such a plasma spectrometer is ideal for Heliophysics plasma investigations, particularly for small satellite and multi-spacecraft missions. Here we present initial measurements of the performance of the instrument components and designs of the electronics for the low energy threshold solid state detector. Work Support under NASA grant - NNX14AJ36G.
Vacuum arc plasma thrusters with inductive energy storage driver
NASA Technical Reports Server (NTRS)
Krishnan, Mahadevan (Inventor)
A plasma thruster with a cylindrical inner and cylindrical outer electrode generates plasma particles from the application of energy stored in an inductor to a surface suitable for the formation of a plasma and expansion of plasma particles. The plasma production results in the generation of charged particles suitable for generating a reaction force, and the charged particles are guided by a magnetic field produced by the same inductor used to store the energy used to form the plasma.
Solid-shape energy fuels from recyclable municipal solid waste and plastics
NASA Astrophysics Data System (ADS)
Gug, Jeongin
Diversion of waste streams, such as plastics, wood and paper, from municipal landfills and extraction of useful materials from landfills is an area of increasing interest across the country, especially in densely populated areas. One promising technology for recycling MSW (municipal solid waste) is to burn the high energy content components in standard coal boilers. This research seeks to reform wastes into briquette that are compatible with typical coal combustion processes. In order to comply with the standards of coal-fired power plants, the feedstock must be mechanically robust, moisture resistance, and retain high fuel value. Household waste with high paper and fibers content was used as the base material for this study. It was combined with recyclable plastics such as PE, PP, PET and PS for enhanced binding and energy efficiency. Fuel pellets were processed using a compression molding technique. The resulting moisture absorption, proximate analysis from burning, and mechanical properties were investigated after sample production and then compared with reference data for commercial coals and biomass briquettes. The effects of moisture content, compression pressure and processing temperature were studied to identify the optimal processing conditions with water uptake tests for the durability of samples under humid conditions and burning tests to examine the composition of samples. Lastly, mechanical testing revealed the structural stability of solid fuels. The properties of fuel briquettes produced from waste and recycled plastics improved with higher processing temperature but without charring the material. Optimization of moisture content and removal of air bubbles increased the density, stability and mechanical strength. The sample composition was found to be more similar to biomass fuels than coals because the majority of the starting material was paper-based solid waste. According to the proximate analysis results, the waste fuels can be expected to have
Advances in plastic recycling. Volume 1: Recycling of polyurethanes
Frisch, K.C.; Klempner, D.; Prentice, G.
``Recycling of Polyurethanes'', the first volume in the Advances in Plastics Recycling series, is focused on the physical and chemical recycling of polyurethanes, with attention given to energy conversion. A compilation of the present ongoing studies on recycling of urethane and, in general, isocyanate-based polymers, the focus is on thermosetting urethane polymers. Contents include: Recycling of Polyurethane Plastics in the European Automotive Industry; Present State of Polyurethane Recycling in Europe; Processing Overview of Bonded Polyurethane Foam; Mechanical Recycling of Polyurethane Scrap; Ecostream{trademark}--A Technology Beyond Recycling; Recycling of Flexible polyurethane Foam; General purpose Adhesives Prepared from Chemically Recycled Waste Rigid Polyurethane Foams; and Utilization of Isocyanate Binders in Recycling of Scrap Automotive Headliners.
Improving the actinides recycling in closed fuel cycles, a major step towards nuclear energy sustainability
Poinssot, C.; Grandjean, S.; Masson, M.; Bouillis, B.; Warin, D.
Increasing the sustainability of nuclear energy is a longstanding road that requires a stepwise approach to successively tackle the following 3 objectives. First of all, optimize the consumption of natural resource to preserve them for future generations and hence guarantee the energetic independence of the countries (no uranium ore is needed anymore). The current twice-through cycle of Pu implemented by France, UK, Japan and soon China is a first step in this direction and already allows the development and optimization of the relevant industrial processes. It also allows a major improvement regarding the conditioning of the ultimate waste in a durable and robust nuclear glass. Secondly, the recycling of americium could be an interesting option for the future with the deployment of FR fleet to save the repository resource and optimize its use by allowing a denser disposal. It would limit the burden towards the future generations and the need for additional repositories before several centuries. Thirdly, the recycling of the whole minor actinides inventory could be an interesting option for the far-future for strongly decreasing the waste long-term toxicity, down to a few centuries. It would bring the waste issue back within the human history, which should promote its acceptance by the social opinion.
Controlling electron energy distributions for plasma technologies
NASA Astrophysics Data System (ADS)
Kushner, Mark
The basic function of low temperature plasmas in society benefiting technologies is to channel power into specific modes of atoms and molecules to excite desired states or produce specified radicals. This functionality ultimately depends on the ability to craft an electron energy distribution (EED) to match cross sections. Given electric fields, frequencies, gas mixtures and pressures, predicting EEDs and excitation rates can in large part be reliably done. The inverse problem, specifying the conditions that produce a given EED, is less well understood. Early strategies to craft EEDs include adjusting gas mixtures, such as the rare gas-Hg mixtures in fluorescent lamps, and externally sustained discharges, such as electron-beam sustained plasmas for molecular lasers. More recent strategies include spiker-sustainer circuitry which produces desired EEDs in non-self-sustained plasmas; and adjusting frequency in capacitively coupled plasmas. In this talk, past strategies for customizing EEDs in low pressure plasmas will be reviewed and prospects for improved control of plasma kinetics will be discussed using results from 2-dimensional computer models.
ERIC Educational Resources Information Center
Martin, Amy
Suggestions for creating a successful office recycling system are enumerated from start up plans to waste reduction and paper recycling. Contact information for recycling equipment, potential buyers of recycled materials, recycled products for purchase, and ideas for promotion and education of staff are included. (MCO)
Processing and properties of a solid energy fuel from municipal solid waste (MSW) and recycled plastics.
Gug, JeongIn; Cacciola, David; Sobkowicz, Margaret J
Diversion of waste streams such as plastics, woods, papers and other solid trash from municipal landfills and extraction of useful materials from landfills is an area of increasing interest especially in densely populated areas. One promising technology for recycling municipal solid waste (MSW) is to burn the high-energy-content components in standard coal power plant. This research aims to reform wastes into briquettes that are compatible with typical coal combustion processes. In order to comply with the standards of coal-fired power plants, the feedstock must be mechanically robust, free of hazardous contaminants, and moisture resistant, while retaining high fuel value. This study aims to investigate the effects of processing conditions and added recyclable plastics on the properties of MSW solid fuels. A well-sorted waste stream high in paper and fiber content was combined with controlled levels of recyclable plastics PE, PP, PET and PS and formed into briquettes using a compression molding technique. The effect of added plastics and moisture content on binding attraction and energy efficiency were investigated. The stability of the briquettes to moisture exposure, the fuel composition by proximate analysis, briquette mechanical strength, and burning efficiency were evaluated. It was found that high processing temperature ensures better properties of the product addition of milled mixed plastic waste leads to better encapsulation as well as to greater calorific value. Also some moisture removal (but not complete) improves the compacting process and results in higher heating value. Analysis of the post-processing water uptake and compressive strength showed a correlation between density and stability to both mechanical stress and humid environment. Proximate analysis indicated heating values comparable to coal. The results showed that mechanical and moisture uptake stability were improved when the moisture and air contents were optimized. Moreover, the briquette
Organic light-emitting devices integrated with solar cells: High contrast and energy recycling
NASA Astrophysics Data System (ADS)
Yang, Chih-Jen; Cho, Ting-Yi; Lin, Chun-Liang; Wu, Chung-Chih
In this letter, the authors report that by integrating organic light-emitting devices (OLEDs) with solar cells, luminous ambient-light reflection as low as 1.4% (even superior to that achieved with polarizers) can be achieved without compromising the electroluminescence efficiency for high-contrast display applications. Furthermore, in such a configuration, the photon energies of the incident ambient light and the portion of OLED emission not getting outside of the device can be recycled into useful electrical power via the photovoltaic action, instead of being totally wasted as in other reported contrast-enhancement techniques. These features, the authors believe, shall make this technique attractive for high-contrast display applications and portable/mobile electronics that are highly power aware.
Processing and properties of a solid energy fuel from municipal solid waste (MSW) and recycled plastics
Gug, JeongIn Cacciola, David Sobkowicz, Margaret J.
Highlights: • Briquetting was used to produce solid fuels from municipal solid waste and recycled plastics. • Optimal drying, processing temperature and pressure were found to produce stable briquettes. • Addition of waste plastics yielded heating values comparable with typical coal feedstocks. • This processing method improves utilization of paper and plastic diverted from landfills. - Abstract: Diversion of waste streams such as plastics, woods, papers and other solid trash from municipal landfills and extraction of useful materials from landfills is an area of increasing interest especially in densely populated areas. One promising technology for recycling municipal solid waste (MSW) is to burn the high-energy-content components in standard coal power plant. This research aims to reform wastes into briquettes that are compatible with typical coal combustion processes. In order to comply with the standards of coal-fired power plants, the feedstock must be mechanically robust, free of hazardous contaminants, and moisture resistant, while retaining high fuel value. This study aims to investigate the effects of processing conditions and added recyclable plastics on the properties of MSW solid fuels. A well-sorted waste stream high in paper and fiber content was combined with controlled levels of recyclable plastics PE, PP, PET and PS and formed into briquettes using a compression molding technique. The effect of added plastics and moisture content on binding attraction and energy efficiency were investigated. The stability of the briquettes to moisture exposure, the fuel composition by proximate analysis, briquette mechanical strength, and burning efficiency were evaluated. It was found that high processing temperature ensures better properties of the product addition of milled mixed plastic waste leads to better encapsulation as well as to greater calorific value. Also some moisture removal (but not complete) improves the compacting process and results in
Energy conversion in the coronal plasma
NASA Technical Reports Server (NTRS)
Martens, P. C. H.
Solar and stellar X-ray emission are the observed waste products of the interplay between magnetic fields and the motion of stellar plasma. Theoretical understanding of the process of coronal heating is of utmost importance, since the high temperature is what defines the corona in the first place. Most of the research described deals with the aspects of the several rivalling theories for coronal heating. The rest of the papers deal with processes of energy conversion related to flares.
Experimental investigation of the quality characteristics of agricultural plastic wastes regarding their recycling and energy recovery potential
Briassoulis, D.; Hiskakis, M.; Babou, E.; Antiohos, S.K.; Papadi, C.
Highlights: Black-Right-Pointing-Pointer Definition of parameters characterising agricultural plastic waste (APW) quality. Black-Right-Pointing-Pointer Analysis of samples to determine APW quality for recycling or energy recovery. Black-Right-Pointing-Pointer Majority of APW samples from various countries have very good quality for recycling. Black-Right-Pointing-Pointer Upper limit of 50% w/w soil contamination in APW acceptable for energy recovery. Black-Right-Pointing-Pointer Chlorine and heavy metals content in APW below the lowest limit for energy recovery. - Abstract: A holistic environmentally sound waste management scheme that transforms agricultural plastic waste (APW) streams into labelled guaranteed quality commodities freely traded in open market has been developed by the European research project LabelAgriWaste. The APW quality is defined by the APW material requirements, translated to technical specifications, for recycling or energy recovery. The present work investigates the characteristics of the APW quality and the key factors affecting it from the introduction of the virgin product to the market to the APW stream reaching the disposer. Samples of APW from different countries were traced from their application to the field through their storage phase and transportation to the final destination. The test results showed that the majority of APW retained their mechanical properties after their use preserving a 'very good quality' for recycling in terms of degradation. The degree of soil contamination concerning the APW recycling and energy recovery potential fluctuates depending on the agricultural plastic category and application. The chlorine and heavy metal content of the tested APW materials was much lower than the maximum acceptable limits for their potential use in cement industries.
Combine waste-to-energy, recycling with fluid-bed boiler
Murphy, M.L.
This article describes a plant that will be the first to incorporate a fluidized-bed boiler to burn refuse-derived fuel exclusively. An effective long-term solid-waste management program will soon be a reality for Bladen, Cumberland, and Hoke counties, North Carolina. The key element of the program is a 600-ton/day waste-to-energy (WTE) facility, scheduled to begin commercial operation later this year. The BCH Energy project, which gets its name from the initials of the three counties it serves, will become the first fluidized-bed boiler in the US designed to be fueled solely by refuse-derived fuel (RDF). As such, it provides an innovative and efficient approach to solid-waste management in several ways: (1) Maximizes community participation in a recovery and recycling effort. (2) Maximizes additional waste handling and hauling efforts. (3) Significantly reducing waste flow into landfill. (4) Eliminating use of fossil fuel for a nearby chemical plant`s energy load. (5) Substantially improves air quality through use of the latest combustion and emissions control technology.
Energy distribution in parallel plate plasma accelerators
NASA Technical Reports Server (NTRS)
Dicapua, M. S.
A parallel plate accelerator operated in the quasi-steady regime of argon mass flow discharges permits, on account of its geometry, the appraisal of the initial ratio of energy disposition into the kinetic and thermal modes of the plasma while retaining the essential features of coaxial high power self-field MPD accelerators. The energy disposition ratio, calculated as the ratio of kinetic energy to enthalpy in the exhaust flow, shows reasonable agreement with the ratio of the induced emf in the accelerator to resistive voltage drop. Both these ratios indicate that the discharge imparts more energy to the flow by resistive heating than by direct body force acceleration. This is turn suggests that other acceleration mechanisms must be responsible for the high performance of conventional MPD arcs.
Benchmarking survey for recycling.
Marley, Margie Charlotte; Mizner, Jack Harry
This report describes the methodology, analysis and conclusions of a comparison survey of recycling programs at ten Department of Energy sites including Sandia National Laboratories/New Mexico (SNL/NM). The goal of the survey was to compare SNL/NM's recycling performance with that of other federal facilities, and to identify activities and programs that could be implemented at SNL/NM to improve recycling performance.
Nuclear energy and radioactive waste disposal in the age of recycling
Conca, James L.; Apted, Michael
The magnitude of humanity's energy needs requires that we embrace a multitude of various energy sources and applications. For a variety of reasons, nuclear energy must be a major portion of the distribution, at least one third. The often-cited strategic hurdle to this approach is nuclear waste disposal. Present strategies concerning disposal of nuclear waste need to be changed if the world is to achieve both a sustainable energy distribution by 2040 and solve the largest environmental issue of the 21. century - global warming. It is hoped that ambitious proposals to replace fossil fuel power generation by alternatives will drop the percentage of fossil fuel use substantially, but the absolute amount of fossil fuel produced electricity must be kept at or below its present 10 trillion kW-hrs/year. Unfortunately, the rapid growth in consumption to over 30 trillion kW-hrs/year by 2040, means that 20 trillion kW-hrs/yr of non-fossil fuel generated power has to come from other sources. If half of that comes from alternative non-nuclear, non-hydroelectric sources (an increase of 3000%), then nuclear still needs to increase by a factor of four worldwide to compensate. Many of the reasons nuclear energy did not expand after 1970 in North America (proliferation, capital costs, operational risks, waste disposal, and public fear) are no longer a problem. The WIPP site in New Mexico, an example of a solution to the nuclear waste disposal issue, and also to public fear, is an operating deep geologic nuclear waste repository in the massive bedded salt of the Salado Formation. WIPP has been operating for eight years, and as of this writing, has disposed of over 50,000 m{sup 3} of transuranic waste (>100 nCi/g but <23 Curie/liter) including high activity waste. The Salado Formation is an ideal host for any type of nuclear waste, especially waste from recycled spent fuel. (authors)
Investigation of the influence of divertor recycling on global plasma confinement in JET ITER-like wall
NASA Astrophysics Data System (ADS)
Tamain, P.; Joffrin, E.; Bufferand, H.; Järvinen, A.; Brezinsek, S.; Ciraolo, G.; Delabie, E.; Frassinetti, L.; Giroud, C.; Groth, M.; Lipschultz, B.; Lomas, P.; Marsen, S.; Menmuir, S.; Oberkofler, M.; Stamp, M.; Wiesen, S.; JET EFDA contributors
The impact of the divertor geometry on global plasma confinement in type I ELMy H-mode has been investigated in the JET tokamak equipped with ITER-Like Wall. Discharges have been performed in which the position of the strike-points was changed while keeping the bulk plasma equilibrium essentially unchanged. Large variations of the global plasma confinement have been observed, the H98 factor changing from typically 0.7 when the outer strike-point is on the vertical or horizontal targets to 0.9 when it is located in the pump duct entrance. Profiles are mainly impacted in the pedestal but core gradient lengths, especially for the density, are also modified. Although substantial differences are observed in the divertor conditions, none seem to correlate directly with the confinement. Modelling with the EDGE2D-EIRENE and SOLEDGE2D-EIRENE transport codes exhibits differences in the energy losses due to neutrals inside the separatrix, but orders of magnitude are too low to explain simply the impact on the confinement.
Long-lasting changes in the cochlear K+ recycling structures after acute energy failure.
Takiguchi, Yoichiro; Sun, Guang-wei; Ogawa, Kaoru; Matsunaga, Tatsuo
Fibrocytes in the cochlear lateral wall and spiral limbus play an important role in transporting K(+) and have the capacity of self-renewal. We showed that acute energy failure in the rat cochlea induced by local administration of the mitochondrial toxin 3-nitropropionic acid (3NP) caused hearing loss in a concentration-dependent manner, mainly due to degeneration of cochlear fibrocytes. We produced long-lasting profound cochlear damage in this model by modifying the 3NP administration protocol and observed morphological changes at 16 weeks after the administration. In the spiral ligament, severe degeneration of fibrocytes was observed in the basal turn, and the levels of the Na,K-ATPase alpha and beta1 subunits and of NKCC1 were decreased in these cells, whereas connexin 26 (Cx26) level increased in the type 1 fibrocytes adjacent to the stria vascularis. In the stria vascularis, levels of Kir4.1 and L-PGDS decreased. In the spiral limbus, severe degeneration of fibrocytes was observed in the middle and basal turns, but NKCC1 and Cx26 were still found in the center of the limbus in the middle turn. These results indicate long-lasting changes in the cochlear lateral wall and spiral limbus, which may compensate for damaged K(+) recycling and protect cells from ATP shortage. PMID:23827367
Waste-recycling Monte Carlo with optimal estimates: application to free energy calculations in alloys.
Adjanor, Gilles; Athènes, Manuel; Rodgers, Jocelyn M
The estimator proposed recently by Delmas and Jourdain for waste-recycling Monte Carlo achieves variance reduction optimally with respect to a control variate that is evaluated directly using the simulation data. Here, the performance of this estimator is assessed numerically for free energy calculations in generic binary alloys and is compared to those of other estimators taken from the literature. A systematic investigation with varying simulation parameters of a simplified system, the anti-ferromagnetic Ising model, is first carried out in the transmutation ensemble using path-sampling. We observe numerically that (i) the variance of the Delmas-Jourdain estimator is indeed reduced compared to that of other estimators; and that (ii) the resulting reduction is close to the maximal possible one, despite the inaccuracy in the estimated control variate. More extensive path-sampling simulations involving an FeCr alloy system described by a many-body potential additionally show that (iii) gradual transmutations accommodate the atomic frustrations; thus, alleviating the numerical ergodicity issue present in numerous alloy systems and eventually enabling the determination of phase coexistence conditions. PMID:21806110
Leonard, I.M.
This paper is a study of the past and present recycling efforts on the Hanford site and options for future improvements in the recycling program. Until 1996, recycling goals were voluntarily set by the waste generators: this year, DOE has imposed goals for all its sites to accomplish by 1999. Hanford is presently meeting the voluntary site goals, but may not be able to meet all the new DOE goals without changes to the program. Most of these new DOE goals are recycling goals: * Reduce the generation of radioactive (low-level) waste from routine operations 50 percent through source reduction and recycling. * Reduce the generation of low-level mixed waste from routine operations 50 percent through source reduction and recycling. * Reduce the generation of hazardous waste from routine operations 50 percent through source reduction and recycling. * Recycle 33 percent of the sanitary waste from all operations. * Increase affirmative procurement of EPA-designated recycled items to 100 percent. The Hanford recycling program has made great strides-there has been a 98 percent increase in the amount of paper recycled since its inception in 1990. Hanford recycles paper, chemicals cardboard, tires, oil, batteries, rags, lead weights, fluorescent tubes, aerosol products, concrete, office furniture, computer software, drums, toner cartridges, and scrap metal. Many other items are recycled or reused by individual groups on a one time basis without a formal contract. Several contracts are closed-loop contracts which involve all parts of the recycle loop. Considerable savings are generated from recycling, and much more is possible with increased attention and improvements to this program. General methods for improving the recycling program to ensure that the new goals can be met are: a Contract and financial changes 0 Tracking database and methods improvements 0 Expanded recycling efforts. Specifically, the Hanford recycling program would be improved by: 0 Establishing one overall
Tarricone, P.
This article examines the efforts of various states in the USA to recycle waste materials in highway construction as fill and pavements. The topics of the article include recycling used tires whole, ground, and shredded, cost of recycling, wood fiber chips as fill material in embankments, and mining wastes used to construct embankments and as coarse aggregates in asphalt pavement.
Energy loss in unstable quark-gluon plasma
NASA Astrophysics Data System (ADS)
Carrington, Margaret E.; Deja, Katarzyna; Mrówczyński, Stanisław
The momentum distribution of quark-gluon plasma at the early stage of a relativistic heavy-ion collision is anisotropic; consequently, the system, which is assumed to be weakly coupled, is unstable owing to chromomagnetic plasma modes. We consider a high-energy parton which flies across such an unstable plasma, and the energy transfer between the parton and the medium is studied as an initial value problem. In the case of equilibrium plasmas, the well-known formula of collisional energy loss is reproduced. The unstable plasma case is much more complex, and the parton can lose or gain energy depending on the initial conditions. The extremely prolate and extremely oblate systems are considered as examples of unstable plasmas, and two classes of initial conditions are discussed. When the initial chromodynamic field is uncorrelated with the color state of the parton, it typically looses energy, and the magnitude of the energy loss is comparable to that in an equilibrium plasma of the same density. When the initial chromodynamic field is induced by the parton, it can be either accelerated or decelerated depending on the relative phase factor. With a correlated initial condition, the energy transfer grows exponentially in time and its magnitude can much exceed the absolute value of energy loss in an equilibrium plasma. The energy transfer is also strongly directionally dependent. Consequences of our findings for the phenomenology of jet quenching in relativistic heavy-ion collisions are briefly discussed.
Beneficial and technological analysis for the recycling of solar grade silicon wastes
NASA Astrophysics Data System (ADS)
Dong, Anping; Zhang, Lifeng; Damoah, Lucas N. W.
In the current paper, different kinds of silicon wastes during the production of SoG-Si were summarized and the beneficial analyses, such as financial value, energy value, CO2 emissions, and efficiency and energy payback time, were briefly discussed for the recycling of SoG-Si wastes. Possible technologies to recycle and purify SoG-Si wastes were reviewed: such as filtration, sedimentation, solidification control, electromagnetic separation, plasma oxidation, centrifugation, and high temperature remelting process, et al.
Energy Measurements of Trapped Electrons from a Plasma Wakefield Accelerator
Kirby, Neal; Auerbach, David; Berry, Melissa; Blumenfeld, Ian; Clayton, Christopher E.; Decer, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Johnson, Devon; Joshi, Chadrashekhar; Katsouleas, Thomas; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.
Recent electron beam driven plasma wakefield accelerator experiments carried out at SLAC indicate trapping of plasma electrons. More charge came out of than went into the plasma. Most of this extra charge had energies at or below the 10 MeV level. In addition, there were trapped electron streaks that extended from a few GeV to tens of GeV, and there were mono-energetic trapped electron bunches with tens of GeV in energy.
Scaling of Energy Gain with Plasma Parameters in a Plasma Wakefield Accelerator
Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.
We have recently demonstrating the doubling of the energy of particles of the ultra-short, ultra-relativistic electron bunches of the Stanford Linear Accelerator Center [1]. This energy doubling occurred in a plasma only 85 cm-long with a density of {approx} 2.6 x 10{sup 17} e{sup -}/cm{sup -3}. This milestone is the result of systematic measurements that show the scaling of the energy gain with plasma length and density, and show the reproducibility and the stability of the acceleration process. We show that the energy gain increases linearly with plasma length from 13 to 31 cm. These are key steps toward the application of beam-driven plasma accelerators or plasma wakefield accelerators (PWFA) to doubling the energy of a future linear collider without doubling its length.
Development of high energy pulsed plasma simulator for plasma-lithium trench experiment
NASA Astrophysics Data System (ADS)
Jung, Soonwook
To simulate detrimental events in a tokamak and provide a test-stand for a liquid lithium infused trench (LiMIT) device, a pulsed plasma source utilizing a theta pinch in conjunction with a coaxial plasma accelerator has been developed. An overall objective of the project is to develop a compact device that can produce 100 MW/m2 to 1 GW/m2 of plasma heat flux (a typical heat flux level in a major fusion device) in ~ 100 mus (≤ 0.1 MJ/m2) for a liquid lithium plasma facing component research. The existing theta pinch device, DEVeX, was built and operated for study on lithium vapor shielding effect. However, a typical plasma energy of 3 - 4 kJ/m2 is too low to study an interaction of plasma and plasma facing components in fusion devices. No or little preionized plasma, ringing of magnetic field, collisions of high energy particles with background gas have been reported as the main issues. Therefore, DEVeX is reconfigured to mitigate these issues. The new device is mainly composed of a plasma gun for a preionization source, a theta pinch for heating, and guiding magnets for a better plasma transportation. Each component will be driven by capacitor banks and controlled by high voltage / current switches. Several diagnostics including triple Langmuir probe, calorimeter, optical emission measurement, Rogowski coil, flux loop, and fast ionization gauge are used to characterize the new device. A coaxial plasma gun is manufactured and installed in the previous theta pinch chamber. The plasma gun is equipped with 500 uF capacitor and a gas puff valve. The increase of the plasma velocity with the plasma gun capacitor voltage is consistent with the theoretical predictions and the velocity is located between the snowplow model and the weak - coupling limit. Plasma energies measured with the calorimeter ranges from 0.02 - 0.065 MJ/m2 and increases with the voltage at the capacitor bank. A cross-check between the plasma energy measured with the calorimeter and the triple probe
Ferlins Show Tissue-Specific Expression and Segregate as Plasma Membrane/Late Endosomal or Trans-Golgi/Recycling Ferlins.
Redpath, Gregory M I; Sophocleous, Reece A; Turnbull, Lynne; Whitchurch, Cynthia B; Cooper, Sandra T
Ferlins are a family of transmembrane-anchored vesicle fusion proteins uniquely characterized by 5-7 tandem cytoplasmic C2 domains, Ca(2+) -regulated phospholipid-binding domains that regulate vesicle fusion in the synaptotagmin family. In humans, dysferlin mutations cause limb-girdle muscular dystrophy type 2B (LGMD2B) due to defective Ca(2+) -dependent, vesicle-mediated membrane repair and otoferlin mutations cause non-syndromic deafness due to defective Ca(2+) -triggered auditory neurotransmission. In this study, we describe the tissue-specific expression, subcellular localization and endocytic trafficking of the ferlin family. Studies of endosomal transit together with 3D-structured illumination microscopy reveals dysferlin and myoferlin are abundantly expressed at the PM and cycle to Rab7-positive late endosomes, supporting potential roles in the late-endosomal pathway. In contrast, Fer1L6 shows concentrated localization to a specific compartment of the trans-Golgi/recycling endosome, cycling rapidly between this compartment and the PM via Rab11 recycling endosomes. Otoferlin also shows trans-Golgi to PM cycling, with very low levels of PM otoferlin suggesting either brief PM residence, or rare incorporation of otoferlin molecules into the PM. Thus, type-I and type-II ferlins segregate as PM/late-endosomal or trans-Golgi/recycling ferlins, consistent with different ferlins mediating vesicle fusion events in specific subcellular locations. PMID:26707827
Plasma response to electron energy filter in large volume plasma device
Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.
An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma.
Plasma response to electron energy filter in large volume plasma device
NASA Astrophysics Data System (ADS)
Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.
An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma.
Paffhausen, M.W.; Smith, D.L.; Ugaki, S.N.
This report describes Phase I of the Solvent Recycle/Recovery Task of the DOE Chlorinated Solvent Substitution Program for the US Air Force by the Idaho National Engineering Laboratory, EG G Idaho, Inc., through the US Department of Energy, Idaho Operations Office. The purpose of the task is to identify and test recovery and recycling technologies for proposed substitution solvents identified by the Biodegradable Solvent Substitution Program and the Alternative Solvents/Technologies for Paint Stripping Program with the overall objective of minimizing hazardous wastes. A literature search to identify recycle/recovery technologies and initial distillation studies has been conducted. 4 refs.
Dense Plasma Focus - From Alternative Fusion Source to Versatile High Energy Density Plasma Source for Plasma Nanotechnology
NASA Astrophysics Data System (ADS)
Rawat, R. S.
The dense plasma focus (DPF), a coaxial plasma gun, utilizes pulsed high current electrical discharge to heat and compress the plasma to very high density and temperature with energy densities in the range of 1-10 × 1010 J/m3. The DPF device has always been in the company of several alternative magnetic fusion devices as it produces intense fusion neutrons. Several experiments conducted on many different DPF devices ranging over several order of storage energy have demonstrated that at higher storage energy the neutron production does not follow I4 scaling laws and deteriorate significantly raising concern about the device's capability and relevance for fusion energy. On the other hand, the high energy density pinch plasma in DPF device makes it a multiple radiation source of ions, electron, soft and hard x-rays, and neutrons, making it useful for several applications in many different fields such as lithography, radiography, imaging, activation analysis, radioisotopes production etc. Being a source of hot dense plasma, strong shockwave, intense energetic beams and radiation, etc, the DPF device, additionally, shows tremendous potential for applications in plasma nanoscience and plasma nanotechnology. In the present paper, the key features of plasma focus device are critically discussed to understand the novelties and opportunities that this device offers in processing and synthesis of nanophase materials using, both, the top-down and bottom-up approach. The results of recent key experimental investigations performed on (i) the processing and modification of bulk target substrates for phase change, surface reconstruction and nanostructurization, (ii) the nanostructurization of PLD grown magnetic thin films, and (iii) direct synthesis of nanostructured (nanowire, nanosheets and nanoflowers) materials using anode target material ablation, ablated plasma and background reactive gas based synthesis and purely gas phase synthesis of various different types of
Local thermodynamic equilibrium in rapidly heated high energy density plasmas
Aslanyan, V.; Tallents, G. J.
Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.
Local thermodynamic equilibrium in rapidly heated high energy density plasmas
NASA Astrophysics Data System (ADS)
Aslanyan, V.; Tallents, G. J.
Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.
Numerical Characterization of Wall Recycling Conditions of the HIDRA Stellarator using EMC3-EIRENE
NASA Astrophysics Data System (ADS)
Marcinko, Steven; Curreli, Davide
The wall recycling conditions created by energetic bombardment of plasma-facing components (PFCs) are of critical importance to determining the plasma and impurity profile in the edge region of a magnetically confined plasma. In this work a pre-online numerical characterization of the edge plasma in HIDRA has been carried out. HIDRA is the former WEGA experiment, now relocated to the University of Illinois at Urbana-Champaign. Numerical simulations of the HIDRA edge environment are performed utilizing the 3D edge plasma and neutral transport code EMC3-EIRENE [Y. Feng J. Nucl. Mater 241-243, 930 (1997)]. In our analysis, emphasis is placed on the influence of the neutrals and the impurities on edge plasma profiles and thus on energy and particle fluxes impingent onto PFCs. We examine the effect of different wall types, comparing high recycling conditions to situations of low recycling. The effect of intrinsic impurity screening is also taken into account under the expected HIDRA operating regimes. We report the calculated particle confinement time and fluid moments of both plasma and neutrals at the low recycling regimes expected with lithium-based PFCs, and compare them with the high recycling regimes found with conventional metal-based PFCs.
On the thermodynamic origin of energy principles in plasma physics
NASA Astrophysics Data System (ADS)
Sicardi Schifino, A. C.; Ferro Fontán, C.; González, R.; Costa, A.
Using the methods of non-equilibrium thermodynamics, we show that the energy principles of plasma stability theory have a common thermodynamic origin. A Lyapunov function, which physically has the meaning of an entropy excess, can be unambiguously constructed under the proviso that no circulatory forces operate in the plasma. Explicit calculations are made which reproduce well-known results applicable to widely different plasma models.
Energy Balance in DC Arc Plasma Melting Furnace
NASA Astrophysics Data System (ADS)
Zhao, Peng; Meng, Yuedong; Yu, Xinyao; Chen, Longwei; Jiang, Yiman; Ni, Guohua; Chen, Mingzhou
In order to treat hazardous municipal solid waste incinerator's (MSWI) fly ash, a new DC arc plasma furnace was developed. Taking an arc of 100 V/1000 A DC as an example, the heat transfer characteristics of the DC arc plasma, ablation of electrodes, heat properties of the fly ash during melting, heat transfer characteristics of the flue gas, and heat loss of the furnace were analyzed based on the energy conservation law, so as to achieve the total heat information and energy balance during plasma processing, and to provide a theoretical basis for an optimized design of the structure and to improve energy efficiency.
Measurement of energy distribution in flowing hydrogen microwave plasmas
NASA Technical Reports Server (NTRS)
Chapman, R.; Morin, T.; Finzel, M.; Hawley, M. C.
An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into kinetic energy of a flowing gas is investigated. A calorimetry system enclosing a microwave plasma system has been developed to accurately measure the energy inputs and outputs of the microwave plasma system. The rate of energy transferred to the gas can be determined to within + or - 1.8 W from an energy balance around the microwave plasma system. The percentage of the power absorbed by the microwave plasma system transferred to the hydrogen gas as it flows through the system is found to increase with the increasing flow rate, to decrease with the increasing pressure, and to be independent of the absorbed power. An upper bound for the hydrogen gas temperature is estimated from the energy content, heat capacity, and flow rate of the gas stream. A lower bound for an overall heat-transfer coefficient is then calculated, characterizing the energy loss from the hydrogen gas stream to the air cooling of the plasma discharge tube wall. The heat-transfer coefficient is found to increase with the increasing flow rate and pressure and to be independent of the absorbed power. This result indicates that a convective-type mechanism is responsible for the energy transfer.
Energy levels of a heavy ion moving in dense plasmas
Hu, Hongwei; Chen, Wencong; Zhao, Yongtao; Li, Fuli; Dong, Chenzhong
In this paper, the potential of a slowly moving test particle moving in collisional dense plasmas is studied. It is composed of the Debye-shielding potential, wake potential, and collision term. The Ritz variational-perturbational method is developed for calculating relativistic binding energy levels of a heavy ion moving in dense plasmas. Binding energy levels of a heavy ion moving in plasmas are calculated. The results show that both non-relativistic energy levels and relativistic energy levels become more negative as the temperature becomes high. They also become more negative as the number density decreasing. Relativistic correction is important for calculating binding energy levels. Both relativistic energy levels and non-relativistic energy levels vary minutely as the speed of heavy ion varies.
Energy coupling to the plasma in repetitive nanosecond pulse discharges
Adamovich, Igor V.; Nishihara, Munetake; Choi, Inchul; Uddi, Mruthunjaya; Lempert, Walter R.
A new analytic quasi-one-dimensional model of energy coupling to nanosecond pulse discharge plasmas in plane-to-plane geometry has been developed. The use of a one-dimensional approach is based on images of repetitively pulsed nanosecond discharge plasmas in dry air demonstrating that the plasma remains diffuse and uniform on a nanosecond time scale over a wide range of pressures. The model provides analytic expressions for the time-dependent electric field and electron density in the plasma, electric field in the sheath, sheath boundary location, and coupled pulse energy. The analytic model predictions are in very good agreement with numerical calculations. The model demonstrates that (i) the energy coupled to the plasma during an individual nanosecond discharge pulse is controlled primarily by the capacitance of the dielectric layers and by the breakdown voltage and (ii) the pulse energy coupled to the plasma during a burst of nanosecond pulses decreases as a function of the pulse number in the burst. This occurs primarily because of plasma temperature rise and resultant reduction in breakdown voltage, such that the coupled pulse energy varies approximately proportionally to the number density. Analytic expression for coupled pulse energy scaling has been incorporated into the air plasma chemistry model, validated previously by comparing with atomic oxygen number density measurements in nanosecond pulse discharges. The results of kinetic modeling using the modified air plasma chemistry model are compared with time-resolved temperature measurements in a repetitively pulsed nanosecond discharge in air, by emission spectroscopy, and purely rotational coherent anti-Stokes Raman spectroscopy showing good agreement.
Energy coupling to the plasma in repetitive nanosecond pulse discharges
NASA Astrophysics Data System (ADS)
Adamovich, Igor V.; Nishihara, Munetake; Choi, Inchul; Uddi, Mruthunjaya; Lempert, Walter R.
A new analytic quasi-one-dimensional model of energy coupling to nanosecond pulse discharge plasmas in plane-to-plane geometry has been developed. The use of a one-dimensional approach is based on images of repetitively pulsed nanosecond discharge plasmas in dry air demonstrating that the plasma remains diffuse and uniform on a nanosecond time scale over a wide range of pressures. The model provides analytic expressions for the time-dependent electric field and electron density in the plasma, electric field in the sheath, sheath boundary location, and coupled pulse energy. The analytic model predictions are in very good agreement with numerical calculations. The model demonstrates that (i) the energy coupled to the plasma during an individual nanosecond discharge pulse is controlled primarily by the capacitance of the dielectric layers and by the breakdown voltage and (ii) the pulse energy coupled to the plasma during a burst of nanosecond pulses decreases as a function of the pulse number in the burst. This occurs primarily because of plasma temperature rise and resultant reduction in breakdown voltage, such that the coupled pulse energy varies approximately proportionally to the number density. Analytic expression for coupled pulse energy scaling has been incorporated into the air plasma chemistry model, validated previously by comparing with atomic oxygen number density measurements in nanosecond pulse discharges. The results of kinetic modeling using the modified air plasma chemistry model are compared with time-resolved temperature measurements in a repetitively pulsed nanosecond discharge in air, by emission spectroscopy, and purely rotational coherent anti-Stokes Raman spectroscopy showing good agreement.
Vacuum arc plasma thrusters with inductive energy storage driver
NASA Technical Reports Server (NTRS)
Schein, Jochen (Inventor); Gerhan, Andrew N. (Inventor); Woo, Robyn L. (Inventor); Au, Michael Y. (Inventor); Krishnan, Mahadevan (Inventor)
An apparatus for producing a vacuum arc plasma source device using a low mass, compact inductive energy storage circuit powered by a low voltage DC supply acts as a vacuum arc plasma thruster. An inductor is charged through a switch, subsequently the switch is opened and a voltage spike of Ldi/dt is produced initiating plasma across a resistive path separating anode and cathode. The plasma is subsequently maintained by energy stored in the inductor. Plasma is produced from cathode material, which allows for any electrically conductive material to be used. A planar structure, a tubular structure, and a coaxial structure allow for consumption of cathode material feed and thereby long lifetime of the thruster for long durations of time.
Comments on experimental results of energy confinement of tokamak plasmas
Chu, T.K.
The results of energy-confinement experiments on steady-state tokamak plasmas are examined. For plasmas with auxiliary heating, an analysis based on the heat diffusion equation is used to define heat confinement time (the incremental energy confinement time). For ohmically sustained plasmas, experiments show that the onset of the saturation regime of energy confinement, marfeing, detachment, and disruption are marked by distinct values of the parameter /bar n//sub e///bar j/. The confinement results of the two types of experiments can be described by a single surface in 3-dimensional space spanned by the plasma energy, the heating power, and the plasma density: the incremental energy confinement time /tau//sub inc/ = ..delta..W/..delta..P is the correct concept for describing results of heat confinement in a heating experiment; the commonly used energy confinement time defined by /tau//sub E/ = W/P is not. A further examination shows that the change of edge parameters, as characterized by the change of the effective collision frequency ..nu../sub e/*, governs the change of confinement properties. The totality of the results of tokamak experiments on energy confinement appears to support a hypothesis that energy transport is determined by the preservation of the pressure gradient scale length. 70 refs., 6 figs., 1 tab.
Nonlinear laser energy depletion in laser-plasma accelerators
Shadwick, B.A.; Schroeder, C.B.; Esarey, E.
Energy depletion of intense, short-pulse lasers via excitation of plasma waves is investigated numerically and analytically. The evolution of a resonant laser pulse proceeds in two phases. In the first phase, the pulse steepens, compresses, and frequency red-shifts as energy is deposited in the plasma. The second phase of evolution occurs after the pulse reaches a minimum length at which point the pulse rapidly lengthens, losing resonance with the plasma. Expressions for the rate of laser energy loss and rate of laser red-shifting are derived and are found to be in excellent agreement with the direct numerical solution of the laser field evolution coupled to the plasma response. Both processes are shown to have the same characteristic length-scale. In the high intensity limit, for nearly-resonant Gaussian laser pulses, this scale length is shown to be independent of laser intensity.
Applications of plasma core reactors to terrestrial energy systems
NASA Technical Reports Server (NTRS)
Latham, T. S.; Biancardi, F. R.; Rodgers, R. J.
Plasma core reactors offer several new options for future energy needs in addition to space power and propulsion applications. Power extraction from plasma core reactors with gaseous nuclear fuel allows operation at temperatures higher than conventional reactors. Highly efficient thermodynamic cycles and applications employing direct coupling of radiant energy are possible. Conceptual configurations of plasma core reactors for terrestrial applications are described. Closed-cycle gas turbines, MHD systems, photo- and thermo-chemical hydrogen production processes, and laser systems using plasma core reactors as prime energy sources are considered. Cycle efficiencies in the range of 50 to 65 percent are calculated for closed-cycle gas turbine and MHD electrical generators. Reactor advantages include continuous fuel reprocessing which limits inventory of radioactive by-products and thorium-U-233 breeder configurations with about 5-year doubling times.-
The injection of energy into the Io plasma torus
NASA Astrophysics Data System (ADS)
Shemansky, D. E.; Sandel, B. R.
Voyager EUV observations of the Io plasma torus indicate the presence of an intensity modulation in the corotating reference frame of significant magnitude on a 10-hour time scale. The phenomenon has a persistence which suggests it is a permanent feature, and the magnitude is such that a substantial amount of energy is injected into the torus at a 10-hour periodic rate. An investigation is conducted regarding the nature of the energy enjection process as determined by the plasma parameters and the observed characteristics. Attention is given to excitation-relaxation relations, aspects of ion-electron relaxation, and electron-electron relaxation and energy transfer rates. The radial distribution of temperature at the eastern and western elongations is found to indicate that the energy input to the electrons is distributed over the width of the torus. The dominant mechanism of energy transport to the plasma appears to be electron-electron heating.
Electron energy distribution in a dusty plasma: analytical approach.
Denysenko, I B; Kersten, H; Azarenkov, N A
Analytical expressions describing the electron energy distribution function (EEDF) in a dusty plasma are obtained from the homogeneous Boltzmann equation for electrons. The expressions are derived neglecting electron-electron collisions, as well as transformation of high-energy electrons into low-energy electrons at inelastic electron-atom collisions. At large electron energies, the quasiclassical approach for calculation of the EEDF is applied. For the moderate energies, we account for inelastic electron-atom collisions in the dust-free case and both inelastic electron-atom and electron-dust collisions in the dusty plasma case. Using these analytical expressions and the balance equation for dust charging, the electron energy distribution function, the effective electron temperature, the dust charge, and the dust surface potential are obtained for different dust radii and densities, as well as for different electron densities and radio-frequency (rf) field amplitudes and frequencies. The dusty plasma parameters are compared with those calculated numerically by a finite-difference method taking into account electron-electron collisions and the transformation of high-energy electrons at inelastic electron-neutral collisions. It is shown that the analytical expressions can be used for calculation of the EEDF and dusty plasma parameters at typical experimental conditions, in particular, in the positive column of a direct-current glow discharge and in the case of an rf plasma maintained by an electric field with frequency f=13.56MHz. PMID:26465570
The Conversion of Large-Scale Turbulent Energy to Plasma Heat In Astrophysical Plasmas
NASA Astrophysics Data System (ADS)
Howes, Gregory
Turbulence in space and astrophysical plasmas plays a key role in the conversion of the energy of violent events and instabilities at large scales into plasma heat. The turbulent cascade transfers this energy from the large scales at which the motions are driven down to small scales, and this essentially fluid process can be understood in terms of nonlinear wave-wave interactions. At sufficiently small scales, for which the dynamics is often weakly collisional, collisionless mechanisms damp the turbulent electromagnetic fluctuations, and this essentially kinetic process can be understood in terms of linear wave-particle interactions. In this talk, I will summarize the possible channels of the turbulent dissipation in a weakly collisional plasma, and present recent results from kinetic numerical simulations of plasma turbulence. Finally, I will discuss strategies for the definitive identification of the dominant dissipation channels using spacecraft measurements of turbulence in the solar wind.
Plasma scale-length effects on electron energy spectra in high-irradiance laser plasmas
NASA Astrophysics Data System (ADS)
Culfa, O.; Tallents, G. J.; Rossall, A. K.; Wagenaars, E.; Ridgers, C. P.; Murphy, C. D.; Dance, R. J.; Gray, R. J.; McKenna, P.; Brown, C. D. R.; James, S. F.; Hoarty, D. J.; Booth, N.; Robinson, A. P. L.; Lancaster, K. L.; Pikuz, S. A.; Faenov, A. Ya.; Kampfer, T.; Schulze, K. S.; Uschmann, I.; Woolsey, N. C.
An analysis of an electron spectrometer used to characterize fast electrons generated by ultraintense (1020W cm-2 ) laser interaction with a preformed plasma of scale length measured by shadowgraphy is presented. The effects of fringing magnetic fields on the electron spectral measurements and the accuracy of density scale-length measurements are evaluated. 2D EPOCH PIC code simulations are found to be in agreement with measurements of the electron energy spectra showing that laser filamentation in plasma preformed by a prepulse is important with longer plasma scale lengths (>8 μ m ).
Magnetowave induced plasma wakefield acceleration for ultrahigh energy cosmic rays.
Chang, Feng-Yin; Chen, Pisin; Lin, Guey-Lin; Noble, Robert; Sydora, Richard
Magnetowave induced plasma wakefield acceleration (MPWA) in a relativistic astrophysical outflow has been proposed as a viable mechanism for the acceleration of cosmic particles to ultrahigh energies. Here we present simulation results that clearly demonstrate the viability of this mechanism for the first time. We invoke the high frequency and high speed whistler mode for the driving pulse. The plasma wakefield obtained in the simulations compares favorably with our newly developed relativistic theory of the MPWA. We show that, under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over hundreds of plasma skin depths. Invoking active galactic nuclei as the site, we show that MPWA production of ultrahigh energy cosmic rays beyond ZeV (10{21} eV) is possible. PMID:19392185
Pulsed Energy Systems for Generating Plasmas
NASA Technical Reports Server (NTRS)
Rose, M. Franklin; Shotts, Z.
This paper will describe the techniques needed to electrically generate highly ionized dense plasmas for a variety of applications. The components needed in pulsed circuits are described in terms of general performance parameters currently available from commercial vendors. Examples of pulsed systems using these components are described and technical data from laboratory experiments presented. Experimental data are given for point designs, capable of multi-megawatt power levels.
High Energy-Density Plasma Production from Plasma-Filled Rod-Pinch Diodes
NASA Astrophysics Data System (ADS)
Schumer, J. W.; Weber, B. V.; Mosher, D.; Apruzese, J. P.
The Plasma-Filled Rod-Pinch diode (PFRP) concentrates a 100-ns, 500-kA, >MeV electron-beam onto the tip of a tapered tungsten rod, generating a High Energy Density Plasma (HEDP). The HEDP (warm dense plasma) is created by deposition of a high-power-density (40 TW/cm^2) electron-beam into solid-density tungsten. The diode current and voltage has been shown to be controllably modified between 260 kA and 1.8 MV to 770 kA and 0.45 MV by increasing the initial plasma-fill density. At the time of peak energy density, analytic estimates using a 0-d self-similar MHD model predict a solid-density (20 g/cm^3) tungsten plasma with 25 eV temperature, 16 Mbar pressure, and 2.4 MJ/cm^3 thermal energy density prior to rapid plasma expansion (after about 10 ns). Temperature and ionization state increase after this time as the rod-tip rapidly expands. This PFRP approach may have advantages for HEDP research. Various applications include high-fluence flash radiography and the study of equation-of-state of materials. Current research results will be presented.
Effects of low-energy-electron-capture collisions (H/sub 0/ + c/sup n+/) on the particle and energy balance of tokamak plasmas
Hogan, J.T.
To illustrate the way in which atomic data provides enlightenment in the search for understandable (and thus extrapolable) confinement models, we restrict our scope to electron capture collisions involving H/sub 0/ and multiply-charged ions. Many such foreign (impurity) multiply-charged ion species are found in plasma discharges, as a result of gas recycling and damage to the surrounding surfaces by energetic plasma particles. Typical low-Z ions are carbon and oxygen; the major constituents of the stainless steel wall (Fe, Ni, Cr) are intermediate impurities, while high-Z impurities (Mo, W) enter from limiter plates which constrict the hot plasma zone to reduce direct plasma-wall contact. In this discussion, however, attention will be given only to applications of data involving H/sub 0/ + C/sup n+/ ..-->.. H/sup +/ + C/sup (n-1)+/ reactions with energy 10 eV to 2 keV. This energy range is typical of the plasma edge in present devices.
Energy exchange in strongly coupled plasmas with electron drift
Akbari-Moghanjoughi, M.; Ghorbanalilu, M.
In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum plasma in the presence of strong electron-beam plasma interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the electron-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of plasma number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the electron-ion collision frequencies are used for strongly coupled ion fluid. The effect of the electron-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in plasmas. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum plasma. The effect of many independent plasma parameters, such as the ion charge-state, electron beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of plasma instability or energy loss/gain of the electron-beam.
Energy exchange in strongly coupled plasmas with electron drift
NASA Astrophysics Data System (ADS)
Akbari-Moghanjoughi, M.; Ghorbanalilu, M.
In this paper, the generalized viscoelastic collisional quantum hydrodynamic model is employed in order to investigate the linear dielectric response of a quantum plasma in the presence of strong electron-beam plasma interactions. The generalized Chandrasekhar's relativistic degeneracy pressure together with the electron-exchange and Coulomb interaction effects are taken into account in order to extend current research to a wide range of plasma number density relevant to big planetary cores and astrophysical compact objects. The previously calculated shear viscosity and the electron-ion collision frequencies are used for strongly coupled ion fluid. The effect of the electron-beam velocity on complex linear dielectric function is found to be profound. This effect is clearly interpreted in terms of the wave-particle interactions and their energy-exchange according to the sign of the imaginary dielectric function, which is closely related to the wave attenuation coefficient in plasmas. Such kinetic effect is also shown to be in close connection with the stopping power of a charged-particle beam in a quantum plasma. The effect of many independent plasma parameters, such as the ion charge-state, electron beam-velocity, and relativistic degeneracy, is shown to be significant on the growing/damping of plasma instability or energy loss/gain of the electron-beam.
Jablonowski, E. ); Carlton, J.
The most common household textiles include clothing, linens, draperies, carpets, shoes, handbags, and rugs. Old clothing, of course, is the most readily reused and/or recycled residentially generated textile category. State and/or local mandates to recycle a percentage of the waste stream are providing the impetus to add new materials to existing collection programs. Concurrently, the textile industry is aggressively trying to increase its throughput by seeking new sources of material to meet increased world demand for product. As experienced with drop-off programs for traditional materials, a majority of residents will not recycle materials unless the collection programs are convenient, i.e., curbside collection. The tonnage of marketable textiles currently being landfilled provide evidence of this. It is the authors' contention that if textile recycling is made convenient and accessible to every household in a municipality or region, then the waste stream disposed may be reduced in a similar fashion as when traditional recyclables are included in curbside programs.
Earth Day 1990: Lesson Plan and Home Survey--K-6. Energy, Solid Waste/Recycling, Toxics, and Water, with Follow-up Activities and Action Guide.
ERIC Educational Resources Information Center
Sly, Carolie; Ruskey, Abby
The purpose of this K-6 curriculum is to provide teachers and other educators with classroom lessons and home surveys that are a starting point for understanding four significant environmental issues--water, toxics, energy, and solid waste/recycling. While each of these environmental issues is complex and has far-reaching implications, the lessons…
Earth Day 1990: Lesson Plan and Home Survey--7-12. Energy, Solid Waste/Recycling, Toxics, Transportation, and Water with Fact Sheets and Action Guide.
ERIC Educational Resources Information Center
Holm-Shuett, Amy; Shuett, Greg
The purpose of this 7-12 curriculum is to provide teachers and other educators with classroom lessons and home surveys that are a starting point for understanding five significant environmental issues - water, toxics, energy, transportation, and solid waste/recycling. While each of these environmental issues is complex and has far-reaching…
Investigation of Ultrasonics as a tool for energy efficient recycling of Lactic acid from postconsumer PLA products
NASA Astrophysics Data System (ADS)
Srinivasan, Gowrishankar
The growing use of "ecofriendly," biodegradable polymers have created a need for a suitable recycling technique because, unlike petroleum derived plastics, their properties deteriorate during conventional recycling. These new techniques must be cost efficient and yield material properties same as virgin polymer. This research investigates the effectiveness of high-power ultrasonics as an efficient technique to recover lactic acid from postconsumer polylactic acid (PLA) products. Polylactic acid is a commercially available bioplastic derived from corn starch and/or sugar cane that is biorenewable and compostable (biodegradable). The various ongoing researches to recover lactic acid from PLA employ a common platform of high temperature, high pressure (HTHP) to effect polymer hydrolysis. The energy intensiveness of these HTHP processes prompted this work to investigate ultrasonics as an low energy alternative process to cause PLA depolymerization. The energy consumption and the time required for depolymerization were utilized as the metrics to quantify and compare depolymerization enhanced by ultrasonics with hot-bath technique. The coupled effect of catalysts concentration and different solvents, along with ultrasonic were studied based on preliminary trial results. In addition, the correlation between the rates of de-polymerization was analyzed for ultrasonic amplitude, treatment time, and catalyst concentration and types. The results indicate that depolymerization of PLA was largely effected by heating caused by ultrasonic-induced cavitations. Other effects of ultrasonics, namely cavitations and acoustic streaming, were shown to have minimal effects in enhancing depolymerization. In fact, thermal energy predominately affected the reaction kinetics; the heat introduced by conventional method (i.e., electrical heaters) was more efficient than ultrasonic heating in terms of energy (for depolymerization) per unit mass of PLA and depolymerizing time. The degree of
NASA Technical Reports Server (NTRS)
Cryopolymers, Inc. tapped NASA expertise to improve a process for recycling vehicle tires by converting shredded rubber into products that can be used in asphalt road beds, new tires, hoses, and other products. In conjunction with the Southern Technology Applications Center and Stennis Space Center, NASA expertise in cryogenic fuel-handling needed for launch vehicle and spacecraft operations was called upon to improve the recycling concept. Stennis advised Cryopolymers on the type of equipment required, as well as steps to reduce the amount of liquid nitrogen used in the process. They also guided the company to use more efficient ways to control system hardware. It is estimated that more than 300 million tires nationwide are produced per year. Cryopolymers expects to reach a production rate of 5,000 tires recycled per day.
Impact of postconsumer recycling initiatives on industrial energy demand-opportunities and threats for natural gas. Final report, December 1991-June 1993
Artz, N.; Kinkelaar, M.; Kirk, M.
The rapid change in municipal solid waste and industrial waste management practices in the U.S. could have significant impact on industrial energy demand and ultimately, natural gas demand. The study examines the impact of increased rates of postconsumer recycling and waste used as fuel on industrial natural gas demand for the time period 1990 to 2005. Increased postconsumer recycling and waste used as fuel are projected to decrease natural gas demand in the U.S. by 29 trillion Btu per year by 1995 and over 71 trillion Btu by 2005. Increased ferrous scrap use in electric are furnaces and postconsumer plastics recycling are projected to cause the most significant loss in natural gas demand.
Investigation of low energy space plasma
NASA Technical Reports Server (NTRS)
Comfort, Richard H.; Horwitz, James L.
An important modification was made in the method for computing ion densities from DE1/RIMS observations, based on the observed relationship between total plasma density and spacecraft potential. An iterative technique was developed to require that this relationship be preserved in all individual observations, not just in the average sense observed. Results of employing this technique were examined closely and are found to generally improve the final densities in terms of agreement with densities obtained from PWI upper hybrid frequency observations. It also has the effect of reducing scatter in the density vs. L profiles.
Staging Laser Plasma Accelerators for Increased Beam Energy
Panasenko, D.; Shu, A. J.; Schroeder, C. B.; Gonsalves, A. J.; Nakamura, K.; Matlis, N. H.; Cormier-Michel, E.; Plateau, G.; Lin, C.; Toth, C.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.
Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10 m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.
Atomic Oxygen Energy in Low Frequency Hyperthermal Plasma Ashers
NASA Technical Reports Server (NTRS)
Banks, Bruce A.; Miller, Sharon K R.; Kneubel, Christian A.
Experimental and analytical analysis of the atomic oxygen erosion of pyrolytic graphite as well as Monte Carlo computational modeling of the erosion of Kapton H (DuPont, Wilmington, DE) polyimide was performed to determine the hyperthermal energy of low frequency (30 to 35 kHz) plasma ashers operating on air. It was concluded that hyperthermal energies in the range of 0.3 to 0.9 eV are produced in the low frequency air plasmas which results in texturing similar to that in low Earth orbit (LEO). Monte Carlo computational modeling also indicated that such low energy directed ions are fully capable of producing the experimentally observed textured surfaces in low frequency plasmas.
Staging laser plasma accelerators for increased beam energy
Panasenko, Dmitriy; Shu, Anthony; Schroeder, Carl; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas; Cormier-Michel, Estelle; Plateau, Guillaume; Lin, Chen; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim
Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies with compact laser systems. The concept of staging includes coupling of additional laser energy and transporting the electron beam from one accelerating module to another. Due to laser damage threshold constraints, in-coupling laser energy with conventional optics requires distances between the accelerating modules of the order of 10m, resulting in decreased average accelerating gradient and complicated e-beam transport. In this paper we use basic scaling laws to show that the total length of future laser plasma accelerators will be determined by staging technology. We also propose using a liquid jet plasma mirror for in-coupling the laser beam and show that it has the potential to reduce distance between stages to the cm-scale.
Theory and application of maximum magnetic energy in toroidal plasmas
Chu, T.K.
The magnetic energy in an inductively driven steady-state toroidal plasma is a maximum for a given rate of dissipation of energy (Poynting flux). A purely resistive steady state of the piecewise force-free configuration, however, cannot exist, as the periodic removal of the excess poloidal flux and pressure, due to heating, ruptures the static equilibrium of the partitioning rational surfaces intermittently. The rupture necessitates a plasma with a negative q{prime}/q (as in reverse field pinches and spheromaks) to have the same {alpha} in all its force-free regions and with a positive q{prime}/q (as in tokamaks) to have centrally peaked {alpha}'s.
Theory and application of maximum magnetic energy in toroidal plasmas
Chu, T.K.
The magnetic energy in an inductively driven steady-state toroidal plasma is a maximum for a given rate of dissipation of energy (Poynting flux). A purely resistive steady state of the piecewise force-free configuration, however, cannot exist, as the periodic removal of the excess poloidal flux and pressure, due to heating, ruptures the static equilibrium of the partitioning rational surfaces intermittently. The rupture necessitates a plasma with a negative q{prime}/q (as in reverse field pinches and spheromaks) to have the same {alpha} in all its force-free regions and with a positive q{prime}/q (as in tokamaks) to have centrally peaked {alpha}`s.
Study on electron beam in a low energy plasma focus
Khan, Muhammad Zubair; Ling, Yap Seong; San, Wong Chiow
Electron beam emission was investigated in a low energy plasma focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the electron beam. XR100CR X-ray spectrometer was used to explore the impact of the electron beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of electron beam is exceptionally notable with two different approaches using lead target inside hollow anode in our plasma focus device.
Modeling Nuclear Fusion in High Energy Density Plasmas Using a Strongly Magnetized Non-neutral Plasma
NASA Astrophysics Data System (ADS)
Dubin, D. H. E.
In the hot dense interiors of stars and giant planets, nuclear reactions are predicted to occur at rates that are greatly enhanced compared to those at low densities. The enhancement is caused by plasma screening of the reacting pairs, increasing the probability of close collisions. However, strongly enhanced nuclear reaction rates have never been observed in the laboratory. This poster discusses a method for observing the enhancement using an analogy between nuclear energy and cyclotron energy in a non-neutral plasma in a strong magnetic field. In such a plasma, cyclotron energy is an adiabatic invariant, and is released only through close collisions that break this invariant. It is shown that the rate of release of cyclotron energy is enhanced by precisely the same factor as that for the release of nuclear energy, because both processes rely on close collisions that are enhanced by plasma screening.ootnotetextD. Dubin, Phys. Rev. Lett. 94, 025002 (2005). Simulations measuring the screening enhancement will be presented, and the possibility of exciting and studying burn fronts will be discussed.ootnotetextSee also adjacent poster by J. Bollinger.
Frontiers in plasma science: a high energy density perspective
NASA Astrophysics Data System (ADS)
Remington, Bruce
The potential for ground-breaking research in plasma physics in high energy density (HED) regimes is compelling. The combination of HED facilities around the world spanning microjoules to megajoules, with time scales ranging from femtoseconds to microseconds enables new regimes of plasma science to be experimentally probed. The ability to shock and ramp compress samples and simultaneously probe them allows dense, strongly coupled, Fermi degenerate plasmas relevant to planetary interiors to be studied. Shock driven hydrodynamic instabilities evolving into turbulent flows relevant to the dynamics of exploding stars are being probed. The physics and dynamics of magnetized plasmas relevant to astrophysics and inertial confinement fusion are also starting to be studied. High temperature, high velocity interacting flows are being probed for evidence of astrophysical collisionless shock formation. Turbulent, high magnetic Reynolds number flows are being experimentally generated to look for evidence of the turbulent magnetic dynamo effect. And new results from thermonuclear reactions in dense hot plasmas relevant to stellar interiors are starting to emerge. A selection of examples providing a compelling vision for frontier plasma science in the coming decade will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Solar energy converter using surface plasma waves
NASA Technical Reports Server (NTRS)
Anderson, L. M. (Inventor)
Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons.
Ames Lab 101: Rare-Earth Recycling
Ryan Ott
Recycling keeps paper, plastics, and even jeans out of landfills. Could recycling rare-earth magnets do the same? Perhaps, if the recycling process can be improved. Scientists at the U.S. Department of Energy's Ames Laboratory are working to more effectively remove the neodymium, a rare earth, from the mix of other materials in a magnet.
Ames Lab 101: Rare-Earth Recycling
Ryan Ott
Recycling keeps paper, plastics, and even jeans out of landfills. Could recycling rare-earth magnets do the same? Perhaps, if the recycling process can be improved. Scientists at the U.S. Department of Energy's Ames Laboratory are working to more effectively remove the neodymium, a rare earth, from the mix of other materials in a magnet.
High energy density Z-pinch plasmas using flow stabilization
Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.
The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and
High energy density Z-pinch plasmas using flow stabilization
NASA Astrophysics Data System (ADS)
Shumlak, U.; Golingo, R. P.; Nelson, B. A.; Bowers, C. A.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Knecht, S. D.; Lambert, K. K.; Lowrie, W.; Ross, M. P.; Weed, J. R.
The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes - Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and scaling
Neutral dynamics and ion energy transport in MST plasma
NASA Astrophysics Data System (ADS)
Xing, Zichuan; Nornberg, Mark; den Hartog, Daniel; Kumar, Santosh; Anderson, Jay
Neutral dynamics can have a significant effect on ion energy transport through charge exchange collisions. Whereas previously charge exchange was considered a direct loss mechanism in MST plasmas, new analysis indicates that significant thermal charge exchange neutrals are reionized. Further, the temperatures of the neutral species in the core of the plasma are suspected to be much higher than room temperature, which has a large effect on ion energy losses due to charge exchange. The DEGAS2 Monte Carlo simulation code is applied to the MST reversed field pinch experiment to estimate the density and temperature profile of the neutral species. The result is then used to further examine the effect of the neutral species on ion energy transport in improved confinement plasmas. This enables the development of a model that accounts for collisional equilibration between species, classical convective and conductive energy transport, and energy loss due to charge exchange collisions. The goal is to quantify classical, stochastic, and anomalous ion heating and transport in RFP plasmas. Work supported by the US DOE. DEGAS2 is provided by PPPL and STRAHL is provided by Ralph Dux of the Max-Planck-Institut fur Plasmaphysik.
Potassium plasma cell facilitates thermionic energy conversion process
NASA Technical Reports Server (NTRS)
Richards, H. K.
Thermionic energy converter converts nuclear generated heat directly into high frequency and direct current output. It consists of a potassium plasma cell, a tantalum emitter, and a silver plated copper collector. This conversion process eliminates the steam interface usually required between the atomic heat source and the electrical conversion system.
Sheath energy transmission in a collisional plasma with collisionless sheath
Tang, Xian-Zhu Guo, Zehua
Sheath energy transmission governs the plasma energy exhaust onto a material surface. The ion channel is dominated by convection, but the electron channel has a significant thermal conduction component, which is dominated by the Knudsen layer effect in the presence of an absorbing wall. First-principle kinetic simulations reveal a robustly supersonic sheath entry flow. The ion sheath energy transmission and the sheath potential are accurately predicted by a sheath model of truncated bi-Maxwellian electron distribution. The electron energy transmission is further enhanced by a parallel heat flux of the perpendicular degrees of freedom.
Relaxation in Plasmas with Several Types of Free Energy
Weiland, Jan
The problem of relaxation in plasmas with several types of free energy is discussed. In particular the competition between the relaxation of different free energies as expressed through e.g. the ratio of length scales such as {eta} = L{sub n}/L{sub T} etc. Parameters giving instability thresholds in linear theory tend to determine the ratio of outgoing, diagonal, fluxes and ingoing pinch fluxes nonlinearly. In general pinch fluxes require the coupling between different instability feedback loops.
Electron energy distributions in a magnetized inductively coupled plasma
Song, Sang-Heon E-mail: email@example.com; Yang, Yang; Kushner, Mark J.
Optimizing and controlling electron energy distributions (EEDs) is a continuing goal in plasma materials processing as EEDs determine the rate coefficients for electron impact processes. There are many strategies to customize EEDs in low pressure inductively coupled plasmas (ICPs), for example, pulsing and choice of frequency, to produce the desired plasma properties. Recent experiments have shown that EEDs in low pressure ICPs can be manipulated through the use of static magnetic fields of sufficient magnitudes to magnetize the electrons and confine them to the electromagnetic skin depth. The EED is then a function of the local magnetic field as opposed to having non-local properties in the absence of the magnetic field. In this paper, EEDs in a magnetized inductively coupled plasma (mICP) sustained in Ar are discussed with results from a two-dimensional plasma hydrodynamics model. Results are compared with experimental measurements. We found that the character of the EED transitions from non-local to local with application of the static magnetic field. The reduction in cross-field mobility increases local electron heating in the skin depth and decreases the transport of these hot electrons to larger radii. The tail of the EED is therefore enhanced in the skin depth and depressed at large radii. Plasmas densities are non-monotonic with increasing pressure with the external magnetic field due to transitions between local and non-local kinetics.
Symmetry Breaking and the Inverse Energy Cascade in a Plasma
NASA Astrophysics Data System (ADS)
Worstell, Matthew; Davis, M. S.; Garnier, D.; Mauel, M. E.; Roberts, T. M.; Kesner, J.
The application of electrostatic bias to high density plasmas with turbulent fluctuations confined by a magnetic dipole are investigated. This research investigates the application of non-symmetric bias and the influence of broken symmetry on strongly turbulent plasmas. Non-symmetric bias is applied through either point biasing or an equatorial array spanning the device. In both cases, the spatial symmetry of applied bias dramatically effects the plasma fluctuations. With bias applied, the plasma achieves a new equilibrium characterized by amplified low order modes and diminished amplitude of higher order modes. Although the turbulent spectrum changes, the RMS fluctuation level is unchanged by the bias. Bias also causes the turbulent electrostatic fluctuations to coalesce into a quasicoherent mode and the appearance of increased coherence. The effect of bias configuration is also seen to change the measured levels of nonlinear coupling. Non-symmetric biasing increases nonlinear coupling in contrast to symmetric biasing. These results represent the first experimental demonstration of symmetry breaking driving the inverse energy cascade in a quasi-two dimensional plasma system. Supported by NSF and U.S. DOE/FES Partnership in Basic Plasma Science and Engineering.
Low energy, high power hydrogen neutral beam for plasma heating
NASA Astrophysics Data System (ADS)
Deichuli, P.; Davydenko, V.; Ivanov, A.; Korepanov, S.; Mishagin, V.; Smirnov, A.; Sorokin, A.; Stupishin, N.
A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.
Optical Diagnostics of Electron Energy Distributions in Low Temperature Plasmas
NASA Astrophysics Data System (ADS)
Wendt, Amy
Passive, non-invasive optical emission measurements provide a means of probing important plasma parameters without introducing contaminants into plasma systems. We investigate the electron energy distribution function (EEDF) in argon containing inductively-coupled plasmas due to dominant role in rates of gas-phase reactions for processing plasmas. EEDFs are determined using measurements of 3p5 4 p --> 3p5 4 s emissions in the 650-1150 nm wavelength range and measured metastable and resonant level concentrations, in conjunction with a radiation model that includes contributions from often neglected but critical processes such as radiation trapping and electron-impact excitation from metastable and resonant levels. Measurements over a wide range of operating conditions (pressure, RF power, Ar/Ne/N2 gas mixtures) show a depletion of the EEDF relative to the Maxwell- Boltzmann form at higher electron energy, in good agreement with measurements made with Langmuir probes and predictions of a global discharge model. This result is consistent with predictions of electron kinetics and can be explained in terms of reduced life times for energetic electrons due to wall losses and inelastic collisions. This example highlights the potential utility of this method as a tool for probing kinetics of many types of low-temperature plasma systems, which are typically characterized by non-Maxwellian EEDFs. This work was supported by the Wisconsin Alumni Research Foundation (WARF) and by NSF Grant CBET 0714600.
Low energy, high power hydrogen neutral beam for plasma heating.
Deichuli, P; Davydenko, V; Ivanov, A; Korepanov, S; Mishagin, V; Smirnov, A; Sorokin, A; Stupishin, N
A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction. PMID:26628137
High energy components and collective modes in thermonuclear plasmas
Coppi, B.; Cowley, S.; Detragiache, P.; Kulsrud, R.; Pegoraro, F.
The theory of a class of collective modes of a thermonuclear magnetically confined plasma, with frequencies in the range of the ion cyclotron frequency and of its harmonics, is presented. These modes can be excited by their resonant cyclotron interaction with a plasma component of relatively high energy particles characterized by a strongly anisotropic distribution in velocity space. Normal modes that are spatially localized by the inhomogeneity of the plasma density are found. This ensures that the energy gained by their resonant interaction is not convected away. The mode spatial localization can be significantly altered by the magnetic field inhomogeneity for a given class of plasma density profiles. Special attention is devoted to the case of a spin polarized plasma, where the charged products of fusion reactions are anisotropically distributed. We show that for the mode of polarization that enhances nuclear reaction rates the tritium will be rapidly depolarized to toroidal configurations with relatively mild gradients of the confining magnetic field. 18 refs., 9 figs.
Low energy, high power hydrogen neutral beam for plasma heating
Deichuli, P.; Davydenko, V.; Ivanov, A. Mishagin, V.; Sorokin, A.; Stupishin, N.; Korepanov, S.; Smirnov, A.
A high power, relatively low energy neutral beam injector was developed to upgrade of the neutral beam system of the gas dynamic trap device and C2-U experiment. The ion source of the injector produces a proton beam with the particle energy of 15 keV, current of up to 175 A, and pulse duration of a few milliseconds. The plasma emitter of the ion source is produced by superimposing highly ionized plasma jets from an array of four arc-discharge plasma generators. A multipole magnetic field produced with permanent magnets at the periphery of the plasma box is used to increase the efficiency and improve the uniformity of the plasma emitter. Multi-slit grids with 48% transparency are fabricated from bronze plates, which are spherically shaped to provide geometrical beam focusing. The focal length of the Ion Optical System (IOS) is 3.5 m and the initial beam diameter is 34 cm. The IOS geometry and grid potentials were optimized numerically to ensure accurate beam formation. The measured angular divergences of the beam are ±0.01 rad parallel to the slits and ±0.03 rad in the transverse direction.
A low-energy linear oxygen plasma source
Anders, Andre; Yushkov, Georgy Yu.
A new version of a Constricted Plasma Source is described,characterized by all metal-ceramic construction, a linear slit exit of180 mm length, and cw-operation (typically 50 kHz) at an average power of1.5 kW. The plasma source is here operated with oxygen gas, producingstreaming plasma that contains mainly positive molecular and atomic ions,and to a much lesser degree, negative ions. The maximum total ion currentobtained was about 0.5 A. The fraction of atomic ions reached more than10 percent of all ions when the flow rate was less then 10 sccm O2,corresponding to a chamber pressure of about 0.5 Pa for the selectedpumping speed. The energy distribution functions of the different ionspecies were measured with a combinedmass spectrometer and energyanalyzer. The time-averaged distribution functions were broad and rangedfrom about 30eV to 90 eV at 200 kHz and higher frequencies, while theywere only several eV broad at 50 kHz and lower frequencies, with themaximum located at about 40 eV for the grounded anode case. This maximumwas shifted down to about 7 eV when the anode was floating, indicatingthe important role of the plasma potential for the ion energy for a givensubstrate potential. The source could be scaled to greater length and maybe useful for functionalization of surfaces and plasma-assisteddeposition of compound films.
Low energy ion distribution measurements in Madison Symmetric Torus plasmas
Titus, J. B. Mezonlin, E. D.; Johnson, J. A.
Charge-exchange neutrals contain information about the contents of a plasma and can be detected as they escape confinement. The Florida A and M University compact neutral particle analyzer (CNPA), used to measure the contents of neutral particle flux, has been reconfigured, calibrated, and installed on the Madison Symmetric Torus (MST) for high temperature deuterium plasmas. The energy range of the CNPA has been extended to cover 0.34–5.2 keV through an upgrade of the 25 detection channels. The CNPA has been used on all types of MST plasmas at a rate of 20 kHz throughout the entire discharge (∼70 ms). Plasma parameter scans show that the ion distribution is most dependent on the plasma current. Magnetic reconnection events throughout these scans produce stronger poloidal electric fields, stronger global magnetic modes, and larger changes in magnetic energy all of which heavily influence the non-Maxwellian part of the ion distribution (the fast ion tail)
NASA Technical Reports Server (NTRS)
Eltahir, Elfatih A. B.; Bras, Rafael L.
The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?
CO2 recycling: a key strategy to introduce green energy in the chemical production chain.
Perathoner, Siglinda; Centi, Gabriele
The introduction of renewable energy in the chemical production chain is a key strategic factor both to realize a sustainable, resource-efficient, low-carbon economy and society and to drive innovation and competiveness in the chemical production. This Concept discusses this concept in terms of motivations, perspectives, and impact as well as technical barriers to achieve this goal. It is shown how an important element to realize this scenario is to foster the paths converting carbon dioxide (CO2) into feedstock for the chemical/process industry, which is one of the most efficient methods to rapidly introduce renewable energy into the chemical production chain. Some of the possible options to proceed in this direction are discussed, with focus on the technical barriers and enabling factors such as catalysis. The tight interconnection between CO2 management and the use of renewable energy is evidenced. PMID:24599714
Counter-facing plasma focus system as a repetitive and/or long-pulse high energy density plasma source
NASA Astrophysics Data System (ADS)
Aoyama, Yutaka; Nakajima, Mitsuo; Horioka, Kazuhiko
A plasma focus system composed of a pair of counter-facing coaxial plasma guns is proposed as a long-pulse and/or repetitive high energy density plasma source. A proof-of-concept experiment demonstrated that with an assist of breakdown and outer electrode connections, current sheets evolved into a configuration for stable plasma confinement at the center of the electrodes. The current sheets could successively compress and confine the high energy density plasma every half period of the discharge current, enabling highly repetitive light emissions in extreme ultraviolet region with time durations in at least ten microseconds.
Conservation of energy and momentum in nonrelativistic plasmas
Sugama, H.; Watanabe, T.-H.; Nunami, M.
Conservation laws of energy and momentum for nonrelativistic plasmas are derived from applying Noether's theorem to the action integral for the Vlasov-Poisson-Ampere system [Sugama, Phys. Plasmas 7, 466 (2000)]. The symmetric pressure tensor is obtained from modifying the asymmetric canonical pressure tensor with using the rotational symmetry of the action integral. Differences between the resultant conservation laws and those for the Vlasov-Maxwell system including the Maxwell displacement current are clarified. These results provide a useful basis for gyrokinetic conservation laws because gyrokinetic equations are derived as an approximation of the Vlasov-Poisson-Ampere system.
Energy level offset analysis of lead atom in laser plasma
NASA Astrophysics Data System (ADS)
Zhou, X. M.; Chen, C. S.; Man, B. Y.; Guo, J.; Wang, J.
The optical emission spectra of the plasma generated by a 1064 nm laser irradiation of lead target in air were recorded and analyzed. Temporal evolvement trait of spectral lines was investigated. The Stark width and line shift were measured at different delay time and laser energies. The electron densities were determined using Stark-broadening parameters of spectral lines. The atomic energy level offset in plasma surroundings was explored by analyzing the line shift. The experimental data of Stark widths and line shifts were analyzed using the regularity of the Stark parameters' dependence on effective ionization potential. However an inverse experimental result was found compared with the theoretical calculation. In addition, the change of the Stark widths and line shifts with the delay time and laser energies was discussed.
High-energy, stable and recycled molecular solar thermal storage materials using AZO/graphene hybrids by optimizing hydrogen bonds.
Luo, Wen; Feng, Yiyu; Qin, Chengqun; Li, Man; Li, Shipei; Cao, Chen; Long, Peng; Liu, Enzuo; Hu, Wenping; Yoshino, Katsumi; Feng, Wei
An important method for establishing a high-energy, stable and recycled molecular solar heat system is by designing and preparing novel photo-isomerizable molecules with a high enthalpy and a long thermal life by controlling molecular interactions. A meta- and ortho-bis-substituted azobenzene chromophore (AZO) is covalently grafted onto reduced graphene oxide (RGO) for solar thermal storage materials. High grafting degree and close-packed molecules enable intermolecular hydrogen bonds (H-bonds) for both trans-(E) and cis-(Z) isomers of AZO on the surface of nanosheets, resulting in a dramatic increase in enthalpy and lifetime. The metastable Z-form of AZO on RGO is thermally stabilized with a half-life of 52 days by steric hindrance and intermolecular H-bonds calculated using density functional theory (DFT). The AZO-RGO fuel shows a high storage capacity of 138 Wh kg(-1) by optimizing intermolecular H-bonds with a good cycling stability for 50 cycles induced by visible light at 520 nm. Our work opens up a new method for making advanced molecular solar thermal storage materials by tuning molecular interactions on a nano-template. PMID:26289389
Elemental concentration analysis in soil contaminated with recyclable urban garbage by tube-excited energy-dispersive X-ray fluorescence
NASA Astrophysics Data System (ADS)
Anjos, M. J.; Lopes, R. T.; Jesus, E. F. O.; Assis, J. T.; Cesareo, R.; Barroso, R. C.; Barradas, C. A. A.
Soil and radish (Raphanus Sp) samples from areas treated with organic compost of recyclable urban garbage were quantitatively analyzed by using tube-excited energy-dispersive X-ray fluorescence analysis. Soils treated with 10, 20 and 30 t/ha of recyclable urban garbage and control soil were analyzed. The layer soils were collected at 0-5, 5-10, 10-20, 20-40, 40-60 cm depth. It was possible simultaneously to determine the elemental concentration of various elements: K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, Sr, Zr and Pb in recyclable urban garbage, soil treated with organic compost of recyclable urban garbage and radish plants cultivated in these soils. The elemental concentration of K, Ca, Ti and Fe were determined at percent level (macro-elements) and the other elements at ppm level (micro-elements). It was also possible to observe a significant increase in the contents of K, Ca, Zn, Rb, Sr, Zr and Pb in the soil treated in comparison with the control soil and it was also verified whether the transport of these elements to radish plants cultivated in these soils occurred.
Tom, G.M.; McManus, J.; Knolle, W.; Stoll, I.
The semiconductor industry uses PFC gases such as CF{sub 4} and C{sub 2}F{sub 6} as etchant and cleaning gases during plasma processes. The gases do not fully react within the reactor chamber. The unused gases enter the atmosphere through the process effluent. These gases have long persistence in the atmosphere and absorb infrared radiation. The PFC gases are, therefore, potential global warming gases. A method is described that will recover and recycle PFC gases. The method that the authors have employed to trap and concentrate the PFC gases is based on a dual bed adsorber. The adsorption material is activated carbon.
Feedback control of plasma electron density and ion energy in an inductively coupled plasma etcher
Lin Chaung; Leou, K.-C.; Huang, H.-M.; Hsieh, C.-H.
Here the authors report the development of a fuzzy logic based feedback control of the plasma electron density and ion energy for high density plasma etch process. The plasma electron density was measured using their recently developed transmission line microstrip microwave interferometer mounted on the chamber wall, and the rf voltage was measured by a commercial impedance meter connected to the wafer stage. The actuators were two 13.56 MHz rf power generators which provided the inductively coupled plasma power and bias power, respectively. The control system adopted the fuzzy logic control algorithm to reduce frequent actuator action resulting from measurement noise. The experimental results show that the first wafer effect can be eliminated using closed-loop control for both poly-Si and HfO{sub 2} etching. In particular, for the HfO2 etch, the controlled variables in this work were much more effective than the previous one where ion current was controlled, instead of the electron density. However, the pressure disturbance effect cannot be reduced using plasma electron density feedback.
Energy absorption in cold inhomogeneous plasmas - The Herlofson paradox.
NASA Technical Reports Server (NTRS)
Crawford, F. W.; Harker, K. J.
Confirmation of Barston's (1964) conclusions regarding the underlying mechanism of the Herlofson paradox by examining in detail several analytically tractable cases of delta-function and sinusoidal excitation. The effects of collisions and nonzero electron temperature in determining the steady state fields and dissipation are considered. Energy absorption without dissipation in plasmas is shown to be analogous to that occurring after application of a signal to a network of lossless resonant circuits. This analogy is pursued and is extended to cover Landau damping in a warm homogeneous plasma in which the resonating elements are the electron streams making up the velocity distribution. Some of the practical consequences of resonant absorption are discussed, together with a number of paradoxical plasma phenomena which can also be elucidated by considering a superposition of normal modes rather than a single Fourier component.
Application of Plasma Waveguides to High Energy Accelerators
Milchberg, Howard M
The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We
Recycling and Life Cycle Issues
Das, Sujit
This chapter addresses recycling and life cycle considerations related to the growing use of lightweight materials in vehicles. The chapter first addresses the benefit of a life cycle perspective in materials choice, and the role that recycling plays in reducing energy inputs and environmental impacts in a vehicle s life cycle. Some limitations of life cycle analysis and results of several vehicle- and fleet-level assessments are drawn from published studies. With emphasis on lightweight materials such as aluminum, magnesium, and polymer composites, the status of the existing recycling infrastructure and technological challenges being faced by the industry also are discussed.
Pathways and mechanisms of endocytic recycling
Grant, Barth D.; Donaldson, Julie G.
Endocytic recycling is coordinated with endocytic uptake to control the composition of the plasma membrane. Although much of our understanding of endocytic recycling has come from studies on the transferrin receptor, a protein internalized through clathrin-dependent endocytosis, increased interest in clathrin-independent endocytosis has led to the discovery of new endocytic recycling systems. Recent insights into the regulatory mechanisms that control endocytic recycling have focused on recycling through tubular carriers and the return to the cell surface of cargo that enters cells through clathrin-independent mechanisms. Recent work emphasizes the importance of regulated recycling in such diverse processes as cytokinesis, cell adhesion and morphogenesis, cell fusion, and learning and memory. PMID:19696797
ERIC Educational Resources Information Center
Pennsylvania State Dept. of Environmental Resources, Harrisburg.
This document contains lesson plans about recycling for teachers in grades K-12. Titles include: (1) "Waste--Where Does It Come From? Where Does It Go?" (2) "Litter Detectives," (3) "Classroom Paper Recycling," (4) "Recycling Survey," (5) "Disposal and Recycling Costs," (6) "Composting Project," (7) Used Motor Oil Recycling," (8) "Unwrapping…
Observation of Inertial Energy Cascade in Interplanetary Space Plasma
Sorriso-Valvo, L.; Noullez, A.; Bruno, R.; Bavassano, B.
Direct evidence for the presence of an inertial energy cascade, the most characteristic signature of hydromagnetic turbulence (MHD), is observed in the solar wind by the Ulysses spacecraft. After a brief rederivation of the equivalent of Yaglom's law for MHD turbulence, a linear relation is indeed observed for the scaling of mixed third-order structure functions involving Elsaesser variables. This experimental result firmly establishes the turbulent character of low-frequency velocity and magnetic field fluctuations in the solar wind plasma.
Plasma-edge studies using carbon resistance probes
Wampler, W.R.
Characterization of erosion and hydrogen-recycling processes occurring at the edge of magnetically confined plasmas requires knowledge of the energy and flux of hydrogen isotopes incident on the materials. A new plasma-edge probe technique, the carbon resistance probe, has been developed to obtain this information. This technique uti
Plastics recycling: challenges and opportunities
Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward
Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3–4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it
Plastics recycling: challenges and opportunities.
Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward
Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it
Sub-micron retarding field energy analyzer for plasma analysis
NASA Astrophysics Data System (ADS)
Blain, Matthew
A retarding field energy analyzer with sub-micron apertures for measurement of ion energy distributions in processing plasmas has been built. The analyzer was fabricated using standard Si integrated circuit materials and processing techniques and consists of a shielding grid, an electron repeller grid, and a collector plate, all made of 400 nm thick polycrystalline silicon thin films. The grids are supported and insulated from each other by 1 μm and 2 μm of SiO_2. The apertures in the grids are nominally 0.8 μm in diameter and are self-aligned, thereby minimizing field leakage and optimizing energy resolution. Ion trajectory modeling using SIMION predicts analyzer dispersion to be less than 0.1 eV for 20 eV incident ions. The analyzer can be operated on the wafer on which it was fabricated or can be separated into 1.6 x 1.2 cm^2 die for use as a discrete probe. The basic functionality of the analyzer has been demonstrated in inductively coupled argon plasmas and measurements show energy spreads of 3-5 eV which are consistent with the expected presheath voltage drops and agree well with measurements made with differentially pumped, macroscopic ion energy analyzers. Changes in mean ion energy as a function of power and pressure agree with the expected scaling trends. Efforts to passivate the Si surfaces with Ni to allow for operation of the analyzer in reactive gas plasmas are also reported.
High-Energy Two-Stage Pulsed Plasma Thruster
NASA Technical Reports Server (NTRS)
Markusic, Tom
A high-energy (28 kJ per pulse) two-stage pulsed plasma thruster (MSFC PPT-1) has been constructed and tested. The motivation of this project is to develop a high power (approximately 500 kW), high specific impulse (approximately 10000 s), highly efficient (greater than 50%) thruster for use as primary propulsion in a high power nuclear electric propulsion system. PPT-1 was designed to overcome four negative characteristics which have detracted from the utility of pulsed plasma thrusters: poor electrical efficiency, poor propellant utilization efficiency, electrode erosion, and reliability issues associated with the use of high speed gas valves and high current switches. Traditional PPTs have been plagued with poor efficiency because they have not been operated in a plasma regime that fully exploits the potential benefits of pulsed plasma acceleration by electromagnetic forces. PPTs have generally been used to accelerate low-density plasmas with long current pulses. Operation of thrusters in this plasma regime allows for the development of certain undesirable particle-kinetic effects, such as Hall effect-induced current sheet canting. PPT-1 was designed to propel a highly collisional, dense plasma that has more fluid-like properties and, hence, is more effectively pushed by a magnetic field. The high-density plasma loading into the second stage of the accelerator is achieved through the use of a dense plasma injector (first stage). The injector produces a thermal plasma, derived from a molten lithium propellant feed system, which is subsequently accelerated by the second stage using mega-amp level currents, which eject the plasma at a speed on the order of 100 kilometers per second. Traditional PPTs also suffer from dynamic efficiency losses associated with snowplow loading of distributed neutral propellant. The twostage scheme used in PPT-I allows the propellant to be loaded in a manner which more closely approximates the optimal slug loading. Lithium propellant
Energy loss of correlated ions in dense plasma
NASA Astrophysics Data System (ADS)
Ahmed, Baida Muhsen; Ahmed, Khalid A.; Ahmed, Riayhd Khalil
The interaction between proton clusters and plasma gas is studied using the dielectric function by fried-conte formalism. The theoretical formula of the potential basis equation derived and the energy loss of incident proton (point-like, correlate and dicluster) with different parameters (velocity, distance, densities and temperatures) is calculated numerically. Two different equations were used to enhance the correlation stopping (ECS), it is clear that the present results are consistent with the dielectric calculation of energy loss at parameters ne = 1017cm-3 and T = (2 - 10) eV. The result showed a good correlation with the previous work.
Accelerating piston action and plasma heating in high-energy density laser plasma interactions
NASA Astrophysics Data System (ADS)
Levy, M. C.; Wilks, S. C.; Baring, M. G.
In the field of high-energy density physics (HEDP), lasers in both the nanosecond and picosecond regimes can drive conditions in the laboratory relevant to a broad range of astrophysical phenomena, including gamma-ray burst afterglows and supernova remnants. In the short-pulse regime, the strong light pressure (>Gbar) associated ultraintense lasers of intensity I > 1018 W/cm2 plays a central role in many HEDP applications. Yet, the behavior of this nonlinear pressure mechanism is not well-understood at late time in the laser-plasma interaction. In this paper, a more realistic treatment of the laser pressure 'hole boring' process is developed through analytical modeling and particle-in-cell simulations. A simple Liouville code capturing the phase space evolution of ponderomotively-driven ions is employed to distill effects related to plasma heating and ion bulk acceleration. Taking into account these effects, our results show that the evolution of the laser-target system encompasses ponderomotive expansion, equipartition, and quasi-isothermal expansion epochs. These results have implications for light piston-driven ion acceleration scenarios, and astrophysical applications where the efficiencies of converting incident Poynting flux into bulk plasma flow and plasma heat are key unknown parameters.
The effect of the inclusion of recycled poultry bedding and the physical form of diet on the performance, ruminal fermentation, and plasma metabolites of fattening lambs.
Mirmohammadi, D; Rouzbehan, Y; Fazaeli, H
During a 125-d experimental period, 24 Afshari × Kurdish male lambs initially weighing 25.2 ± 1.2 kg were grouped by BW and randomly assigned to treatments under a completely randomized design with a 2 × 2 factorial arrangement of treatments to evaluate the effects of feeding recycled poultry bedding (RPB; 0 and 200 g/kg DM) and the physical form of the diet (mash and block) on nutrient intake and digestibility, ruminal and plasma parameters, microbial N supply, N balance, feeding behavior, and growth performance of the lambs. Two diets with and without RPB in both mash and block form were prepared. Neither the inclusion of RPB nor the physical form of the diet affected the concentration of VFA or the total tract apparent digestibility of nutrients. Dietary RPB inclusion increased DMI ( < 0.01), tended ( = 0.10) to reduce ADG, and decreased G:F ( = 0.05). The physical form of the diet had no effect on DMI but decreased ADG ( = 0.01) and G:F ( = 0.02) in lambs fed on the block diet compared with those fed on the mash diet. Neither the inclusion of RPB nor the physical form of the diets had any effect on microbial N supply (g/d) and N retention. Rate of eating ( = 0.07), time spent eating ( = 0.87) and ruminating ( = 0.28), and total chewing activity ( = 0.65) were not affected by dietary RPB inclusion. Rate of eating decreased ( < 0.01) and time spent eating and total chewing activity increased ( = 0.01 and = 0.02, respectively) in lambs fed on the block diet compared with those fed on the mash diet. Results of the current study showed that inclusion of RPB up to 200 g/kg DM in diets for fattening was possible without any effect on performance and animal health. Processing of feed into the mash form gave higher livestock productivity in comparison to the block form. PMID:26440164
Plasma structure and energy dependence in a magnetic thrust chamber system
NASA Astrophysics Data System (ADS)
Morita, T.; Yamamoto, N.; Kawashima, R.; Saito, N.; Edamoto, M.; Fujioka, S.; Itadani, Y.; Johzaki, T.; Miura, S.; Mori, Y.; Nishimura, H.; Sunahara, A.; Yogo, A.; Nakashima, H.
We demonstrate a magnetic thrust chamber system, in which an expanding plasma is controlled by an external magnetic field to produce a thrust. The plasma structure and energy dependences are discussed in terms of the drive laser energy and magnetic field strength. The density distribution from two different experiments show identical structure despite the laser energy is different by two order of magnitude when the ratio of magnetic field to plasma energy is more or less same. The experimental results indicate that this ratio is one of the essential factors to extrapolate the plasma dynamics for much larger energy such as inertial confinement fusion plasmas.
Observations of shear flows in high-energy-density plasmas
NASA Astrophysics Data System (ADS)
Harding, Eric C.
The research discussed in this thesis represents work toward the demonstration of experimental designs for creating a Kelvin-Helmholtz (KH) unstable shear layer in a high-energy-density (HED) plasma. Such plasmas are formed by irradiating materials with several kilo-Joules of laser light over a few nanoseconds, and are defined as having an internal pressure greater than one-million atmospheres. Similar plasmas exist in laboratory fusion experiments and in the astrophysical environment. The KH instability is a fundamental fluid instability that arises when strong velocity gradients exist at the interface between two fluids. The KH instability is important because it drives the mixing of fluids and initiates the transition to turbulence in the flow. Until now, the evolution of the KH instability has remained relatively unexplored in the HED regime This thesis presents the observations and analysis of two novel experiments carried out using two separate laser facilities. The first experiment used 1.4 kJ from the Nike laser to generate a supersonic flow of Al plasma over a low-density, rippled foam surface. The Al flow interacted with the foam and created distinct features that resulted from compressible effects. In this experiment there is little evidence of the KH instability. Nevertheless, this experimental design has perhaps pioneered a new method for generating a supersonic shear flow that has the potential to produce the KH instability if more laser energy is applied. The second experiment was performed on the Omega laser. In this case 4.3 kJ of laser energy drove a blast wave along a rippled foam/plastic interface. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vorticies characteristic of the KH instability. The Omega experiment was the first HED experiment to capture the evolution of the KH instability.
High performance polyester concrete using recycled PET
Rebeiz, K.S.
Recycled polyethylene terephthalate (PET) plastic wastes could be used in production of unsaturated polyester resins. In turn, these resins could be mixed with inorganic aggregates to produce polymer concrete (PC). Unsaturated polyesters based on recycled PET might be a potentially lower source cost of resins for producing useful PC based-products. The advantage of recycling PET in PC is that the PET materials do not have to be purified, including removal of colors, to the same extent as other PET recycling applications, which should facilitate the recycling operation and minimize its cost. The recycling of PET in PC could also help save energy and allow the long term disposal of the PET waste, an important advantage in recycling applications.
Damped Modes in Plasma Microturbulence: Saturation, Regulation, and Energy Partition
NASA Astrophysics Data System (ADS)
Makwana, Kiritkumar D.
Plasma microturbulence at the scale of the ion gyroradius and smaller is considered to be the primary cause of heat loss in tokamaks. Damped modes are stable roots of the plasma dispersion relation and form an inseparable part of the microturbulent spectrum. We study several microturbulence models that describe vastly different fusion plasmas. All of them show saturation by damped modes that dissipate energy at almost the same rate as the energy injection rate of the unstable modes. Dissipation by damped modes peaks at low wavenumbers where the instability also peaks, distinguishing it from the traditional viscous dissipation mechanism at large wavenumbers. Damped modes are typically found to be important in saturation when their damping rate is not much larger than the instability growth rate. Until now, the regulation of ion temperature gradient driven (ITG) turbulence by zonal flows has been explained using the zonal flow-drift wave shearing paradigm: zonal flow shearing enhances energy transfer from large scale drift waves to smaller, dissipative scales. However, we show, in both fluid and gyrokinetic simulations, that the zonal flows help transfer a majority of the energy injected by the unstable modes to the damped modes, leading to saturation. Although the transfer to damped modes simultaneously excites smaller scales, a significant fraction of the injected energy is dissipated by damped modes in the large-scale, unstable region. This transfer occurs via three-wave interactions that include a zonal flow, an unstable mode and a damped mode. Such interactions dominate due to their coupling coefficients, the strong zonal flow amplitude and their minimum frequency sum that leads to the largest correlation time and enhanced energy transfer. The slew of damped modes in gyrokinetic simulations is analyzed using proper orthogonal decomposition (POD) modes and linear eigenmodes. Spectra of energy and amplitude attenuation rates of damped modes are calculated, showing
Electron energy spectrum in circularly polarized laser irradiated overdense plasma
Liu, C. S.; Tripathi, V. K.; Shao, Xi; Kumar, Pawan
A circularly polarized laser normally impinged on an overdense plasma thin foil target is shown to accelerate the electrons in the skin layer towards the rear, converting the quiver energy into streaming energy exactly if one ignores the space charge field. The energy distribution of electrons is close to Maxwellian with an upper cutoff ε{sub max}=mc{sup 2}[(1+a{sub 0}{sup 2}){sup 1/2}−1], where a{sub 0}{sup 2}=(1+(2ω{sup 2}/ω{sub p}{sup 2})|a{sub in}|{sup 2}){sup 2}−1, |a{sub in}| is the normalized amplitude of the incident laser of frequency ω, and ω{sub p} is the plasma frequency. The energetic electrons create an electrostatic sheath at the rear and cause target normal sheath acceleration of protons. The energy gain by the accelerated ions is of the order of ε{sub max}.
Modeling Plasmas with a Kappa Electron Energy Distribution
NASA Astrophysics Data System (ADS)
Hahn, Michael; Savin, Daniel Wolf
Nonthermal kappa electron energy distributions have been observed in the Earth's magnetosphere and the solar wind, and are likely also present in the solar corona and in solar flares. In order to model the spectra of these plasmas, it is necessary to obtain the appropriate collision rate coefficients. We show that this can be done simply by summing appropriately weighted Maxwellian rate coefficients. The resulting data have similar or better accuracies than are obtained with other approaches. Summing Maxwellians has the additional advantages of being easy to implement and extendable to many different collision processes. We apply this technique to modeling the charge state distribution (CSD) of kappa-distribution plasmas. In particular, we examine the influence of electron impact multiple ionization on the equilibrium CSD and calculate the time variation of the CSD during a solar flare.
Modeling Plasmas with a Kappa Electron Energy Distribution
NASA Astrophysics Data System (ADS)
Hahn, Michael; Savin, Daniel Wolf
Nonthermal kappa electron energy distributions have been observed in the Earth's magnetosphere and the solar wind, and are likely also present in the solar corona and in solar flares. In order to model the spectra of these plasmas, it is necessary to obtain the appropriate collision rate coefficients. We show that this can be done simply by summing appropriately weighted Maxwellian rate coefficients. The resulting data have similar or better accuracies than are obtained with other approaches. Summing Maxwellians has the additional advantages of being easy to implement and extendable to many different collision processes. We apply this technique to modeling the charge state distribution (CSD) of kappa-distribution plasmas. In particular, we examine the influence of electron impact multiple ionization on the equilibrium CSD and calculate the time variation of the CSD during a solar flare.
Energy efficiency in nanoscale synthesis using nanosecond plasmas
Pai, David Z.; (Ken) Ostrikov, Kostya; Kumar, Shailesh; Lacoste, Deanna A.; Levchenko, Igor; Laux, Christophe O.
We report a nanoscale synthesis technique using nanosecond-duration plasma discharges. Voltage pulses 12.5 kV in amplitude and 40 ns in duration were applied repetitively at 30 kHz across molybdenum electrodes in open ambient air, generating a nanosecond spark discharge that synthesized well-defined MoO3 nanoscale architectures (i.e. flakes, dots, walls, porous networks) upon polyamide and copper substrates. No nitrides were formed. The energy cost was as low as 75 eV per atom incorporated into a nanostructure, suggesting a dramatic reduction compared to other techniques using atmospheric pressure plasmas. These findings show that highly efficient synthesis at atmospheric pressure without catalysts or external substrate heating can be achieved in a simple fashion using nanosecond discharges. PMID:23386976
New approaches to recycling tires
Spencer, R.
Steel-belted radial tires are potentially one of the most recyclable products created by modern industry, although the potential has been barely tapped. Discarded tires pile up at an astonishing rate each year - 234 million in the US and 26 million passenger tire equivalents in Canada. They represent a mother lode of raw material waiting for modern day miners to transform them into recycled rubber, steel, fiber and energy. The tremendous increase in use of steel belted radials since the early 1970s has complicated their recyclability compared to the bias ply tire, but it has also accomplished waste reduction by tripling tire service life. Part one of this report describes processes being developed to convert tires to crumb rubber, as well as some potential uses of recycled rubber. Part two, to appear next month, will examine such uses as rubberized athletic tracks and highway asphalt.
Chelsea Hubbard
The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D&D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D&D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D&D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D&D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness of separating
Exploration of Plasma Jets Approach to High Energy Density Physics. Final report
Chen, Chiping
High-energy-density laboratory plasma (HEDLP) physics is an emerging, important area of research in plasma physics, nuclear physics, astrophysics, and particle acceleration. While the HEDLP regime occurs at extreme conditions which are often found naturally in space but not on the earth, it may be accessible by colliding high intensity plasmas such as high-energy-density plasma jets, plasmoids or compact toroids from plasma guns. The physics of plasma jets is investigated in the context of high energy density laboratory plasma research. This report summarizes results of theoretical and computational investigation of a plasma jet undergoing adiabatic compression and adiabatic expansion. A root-mean-squared (rms) envelope theory of plasma jets is developed. Comparison between theory and experiment is made. Good agreement between theory and experiment is found.
Energy balance for sustained spheromak plasmas in SSPX
NASA Astrophysics Data System (ADS)
Hill, D. N.; Auerbach, D.; Bulmer, R.; McLean, H.; Wood, R.; Woodruff, S.
Formation of self-organized spheromak plasmas requires, at a minimum, that the input power exceed the loss power in order to increase magnetic field strength. Other factors, such as injector geometry or low-order MHD modes, are also thought to affect the formation process. In SSPX we measure both the input power at the coaxial source, and the loss power to the flux conserver (radiation and plasma conduction) to obtain the global power balance which we can relate to the field buildup. The radiation loss is determined by wide field-of-view bolometers, both time-integrated and time-resolved. Radiation losses are dominated by low-Z impurities and are typically less than 20energy input for clean discharges. We use edge magnetic probe measurements as input to the CORSICA code to determine the total stored magnetic energy and ohmic heating power, which then allows us to compute the energy confinement time from density and temperature profiles obtained by Thomson scattering. This work was performed under the auspices of US DOE by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.
Free energy and entropy flows in magnetised plasma turbulence
NASA Astrophysics Data System (ADS)
Schekochihin, A.; Cowley, S.; Dorland, W.; Howes, G. G.; Quataert, E.; Tatsuno, T.; Plunk, G.; TenBarge, J.; Mallet, A.; Kanekar, A.
Just as fluid turbulence can be conceptualised as a cascade of kinetic energy from large to small scales, kinetic plasma turbulence is a cascade of free energy in the 6D phase space (position and velocity). I will discuss this as a general principle and then specialise to the case of magnetised plasma turbulence at kinetic (sub-ion-Larmor) scales. At these scales, the free energy flux arriving from the inertial range splits into two channels: the kinetic Alfven wave cascade destined to be dissipated into electron heat and the ion entropy cascade, resulting in ion heating. The phase-space nature of the cascade is particularly manifest in this case as the ion entropy cascade involves simultaneous generation of small spatial scales and small scales in velocity space, the latter via a nonlinear phase-mixing process due to ion gyromotion. I will also discuss how the electron Landau damping and the associated process of parallel phase mixing fit into this cascade picture and whether they represent an effective dissipation mechanism in a strongly turbulent nonlinear system.
Plasma Synthesis of Nanoparticles for Nanocomposite Energy Applications
Peter C. Kong; Alex W. Kawczak
The nanocomposite energy applications for plasma reactor produced nanoparticles are reviewed. Nanoparticles are commonly defined as particles less than 100 nm in diameter. Due to this small size, nanoparticles have a high surface-to-volume ratio. This increases the surface energy compared to the bulk material. The high surface-to-volume ratio and size effects (quantum effects) give nanoparticles distinctive chemical, electronic, optical, magnetic and mechanical properties from those of the bulk material. Nanoparticles synthesis can be grouped into 3 broad approaches. The first one is wet phase synthesis (sol-gel processing), the second is mechanical attrition, and the third is gas-phase synthesis (aerosol). The properties of the final product may differ significantly depending on the fabrication route. Currently, there are no economical large-scale production processes for nanoparticles. This hinders the widespread applications of nanomaterials in products. The Idaho National Laboratory (INL) is engaging in research and development of advanced modular hybrid plasma reactors for low cost production of nanoparticles that is predicted to accelerate application research and enable the formation of technology innovation alliances that will result in the commercial production of nanocomposites for alternative energy production devices such as fuel cells, photovoltaics and electrochemical double layer capacitors.
NASA Astrophysics Data System (ADS)
Jacoby, Bryan Anthony
In a survey of ~4,150 square degrees, we discovered 26 previously unknown pulsars, including 7 "recycled" millisecond or binary pulsars. The most significant discovery of this survey is PSR J1909-3744, a 2.95 ms pulsar in an extremely circular 1.5 d orbit with a low-mass white dwarf companion. Though this system is a fairly typical low-mass binary pulsar (LMBP) system, it has several exceptional qualities: an extremely narrow pulse profile and stable rotation have enabled the most precise long-term timing ever reported, and a nearly edge-on orbit gives rise to a strong Shapiro delay which has allowed the most precise measurement of the mass of a millisecond pulsar: m p = (1.438 +/- 0.024) [Special characters omitted.] . Our accurate parallax distance measurement, d p = ([Special characters omitted.] ) kpc, combined with the mass of the optically-detected companion, m c = (0.2038 +/- 0.022) [Special characters omitted.] , will provide an important calibration for white dwarf models relevant to other LMBP companions. We have detected optical counterparts for two intermediate mass binary pulsar (IMBP) systems; taken together with optical detections and non-detections of several similar systems, our results indicate that the characteristic age t = c P /2 P consistently overestimates the time since the end of mass accretion in these recycled systems. We have measured orbital decay in the double neutron star system PSR B2127+11C in the globular cluster M15. This has allowed an improved measurement of the mass of the pulsar, m p = (1.3584 +/- 0.0097) [Special characters omitted.] , and companion, m c = (1.3544 +/- 0.0097) [Special characters omitted.] , as well as a test of general relativity at the 3% level. We find that the proper motions of this pulsar as well as PSR B2127+11A and PSR B2127+11B are consistent with each other and with one published measurement of the cluster proper motion. We have discovered three binary millisecond pulsars in the globular cluster M62
Observation of inertial energy cascade in interplanetary space plasma.
Sorriso-Valvo, L; Marino, R; Carbone, V; Noullez, A; Lepreti, F; Veltri, P; Bruno, R; Bavassano, B; Pietropaolo, E
Direct evidence for the presence of an inertial energy cascade, the most characteristic signature of hydromagnetic turbulence (MHD), is observed in the solar wind by the Ulysses spacecraft. After a brief rederivation of the equivalent of Yaglom's law for MHD turbulence, a linear relation is indeed observed for the scaling of mixed third-order structure functions involving Elsässer variables. This experimental result firmly establishes the turbulent character of low-frequency velocity and magnetic field fluctuations in the solar wind plasma. PMID:17930445
Plasma polymerized high energy density dielectric films for capacitors
NASA Technical Reports Server (NTRS)
Yamagishi, F. G.
High energy density polymeric dielectric films were prepared by plasma polymerization of a variety of gaseous monomers. This technique gives thin, reproducible, pinhole free, conformable, adherent, and insoluble coatings and overcomes the processing problems found in the preparation of thin films with bulk polymers. Thus, devices are prepared completely in a vacuum environment. The plasma polymerized films prepared all showed dielectric strengths of greater than 1000 kV/cm and in some cases values of greater than 4000 kV/cm were observed. The dielectric loss of all films was generally less than 1% at frequencies below 10 kHz, but this value increased at higher frequencies. All films were self healing. The dielectric strength was a function of the polymerization technique, whereas the dielectric constant varied with the structure of the starting material. Because of the thin films used (thickness in the submicron range) surface smoothness of the metal electrodes was found to be critical in obtaining high dielectric strengths. High dielectric strength graft copolymers were also prepared. Plasma polymerized ethane was found to be thermally stable up to 150 C in the presence of air and 250 C in the absence of air. No glass transitions were observed for this material.
A Midsize Tokamak As Fast Track To Burning Plasmas
E. Mazzucato
This paper presents a midsize tokamak as a fast track to the investigation of burning plasmas. It is shown that it could reach large values of energy gain (≥10) with only a modest improvement in confinement over the scaling that was used for designing the International Thermonuclear Experimental Reactor (ITER). This could be achieved by operating in a low plasma recycling regime that experiments indicate can lead to improved plasma confinement. The possibility of reaching the necessary conditions of low recycling using a more efficient magnetic divertor than those of present tokamaks is discussed.
Green Science: Revisiting Recycling
ERIC Educational Resources Information Center
Palliser, Janna
Recycling has been around for a long time--people have reused materials and refashioned them into needed items for thousands of years. More recently, war efforts encouraged conservation and reuse of materials, and in the 1970s recycling got its official start when recycling centers were created. Now, curbside recycling programs and recycling…
Low-Energy Hot Plasma and Particles in Saturn's Magnetosphere.
Krimigis, S M; Armstrong, T P; Axford, W I; Bostrom, C O; Gloeckler, G; Keath, E P; Lanzerotti, L J; Carbary, J F; Hamilton, D C; Roelof, E C
The low-energy charged particle instrument on Voyager 2 measured low-energy electrons and ions (energies greater, similar 22 and greater, similar 28 kiloelectron volts, respectively) in Saturn's magnetosphere. The magnetosphere structure and particle population were modified from those observed during the Voyager 1 encounter in November 1980 but in a manner consistent with the same global morphology. Major results include the following. (i) A region containing an extremely hot ( approximately 30 to 50 kiloelectron volts) plasma was identified and extends from the orbit of Tethys outward past the orbit of Rhea. (ii) The low-energy ion mantle found by Voyager 1 to extend approximately 7 Saturn radii inside the dayside magnetosphere was again observed on Voyager 2, but it was considerably hotter ( approximately 30 kiloelectron volts), and there was an indication of a cooler ( < 20 kiloelectron volts) ion mantle on the nightside. (iii) At energies greater, similar 200 kiloelectron volts per nucleon, H(1), H(2), and H(3) (molecular hydrogen), helium, carbon, and oxygen are important constituents in the Saturnian magnetosphere. The presence of both H(2) and H(3) suggests that the Saturnian ionosphere feeds plasma into the magnetosphere, but relative abundances of the energetic helium, carbon, and oxygen ions are consistent with a solar wind origin. (iv) Low-energy ( approximately 22 to approximately 60 kiloelectron volts) electron flux enhancements observed between the L shells of Rhea and Tethys by Voyager 2 on the dayside were absent during the Voyager 1 encounter. (v) Persistent asymmetric pitch-angle distributions of electrons of 60 to 200 kiloelectron volts occur in the outer magnetosphere in conjunction with the hot ion plasma torus. (vi) The spacecraft passed within approximately 1.1 degrees in longitude of the Tethys flux tube outbound and observed it to be empty of energetic ions and electrons; the microsignature of Enceladus inbound was also observed. (vii
Measurements of energy distribution and wall temperature in flowing hydrogen microwave plasma systems
NASA Technical Reports Server (NTRS)
Chapman, R.; Finzel, M.; Hawley, M. C.
An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into translational energy of the flowing gas is being investigated. A calorimetric experimental system has been designed and built enclosing the microwave plasma system to accurately determine the net energy transferred to the flowing gas. For a flow rate of 8900 micromoles/sec, a pressure of 7.4 torr, and an absorbed power level of 80 W, an energy transfer efficiency of 50 percent has been measured. A heat transfer model that characterizes the energy transfer processes in the plasma is developed. A wall temperature for the plasma system is calculated.
Spatial measurements of electron energy distribution and plasma parameters in a weakly magnetized inductive discharge
Kim, Young-Do; Lee, Young-Kwang; Lee, Hyo-Chang; Chung, Chin-Wook
Spatial characteristics of plasma parameters such as electron temperature, plasma density, plasma potential, and electron energy distribution (EED) were studied in inductively coupled plasma with an axial dc magnetic field. With dc magnetic field, the measured EEDs in the total electron energy scale are spatially coincided except cutting of the low electron energy part indicating the conserved non-local electron kinetics in an axial direction, even though the dc magnetic field is applied. Spatial distributions of the plasma densities at axial positions have almost same trends with various magnetic field strengths. We also discuss the reduction of the ambipolar potential along the axial direction as the applied magnetic field increased.
Ion energy distribution functions in a supersonic plasma jet
NASA Astrophysics Data System (ADS)
Caldirola, S.; Roman, H. E.; Riccardi, C.
Starting from experimental measurements of ion energy distribution functions (IEDFs) in a low pressure supersonic plasma jet, we propose a model to simulate them numerically from first principles calculations. Experimentally we acquired IEDFs with a quadrupole mass spectrometer (QMS) collecting the argon ions produced from a inductively coupled plasma (ICP) and driven into a supersonic free gas expansion. From the discussion of these results and the physics of our system we developed a simulation code. Integrating the equations of motion the code evolves the trajectory of a single ion across the jet. Ar+- Ar collisions are modelled with a 12-4 Lennard-Jones potential which considers induced dipole interactions. IEDFs were simulated at different positions along the jet and compared with the experimental data showing good agreement. We have also implemented a charge transfer mechanism in which the ion releases its charge to a neutral atom which can take place at sufficiently close distances and is a function of the impact energy.
Influence of emitter temperature on the energy deposition in a low-pressure plasma
NASA Astrophysics Data System (ADS)
Levko, Dmitry; Raja, Laxminarayan L.
The influence of emitter temperature on the energy deposition into low-pressure plasma is studied by the self-consistent one-dimensional Particle-in-Cell Monte Carlo Collisions model. Depending on the emitter temperature, different modes of discharge operation are obtained. The mode type depends on the plasma frequency and does not depend on the ratio between the densities of beam and plasma electrons. Namely, plasma is stable when the plasma frequency is small. For this plasma, the energy transfer from emitted electrons to plasma electrons is inefficient. The increase in the plasma frequency results first in the excitation of two-stream electron instability. However, since the thermal velocity of plasma electrons is smaller than the electrostatic wave velocity, the resonant wave-particle interaction is inefficient for the energy deposition into the plasma. Further increase in the plasma frequency leads to the distortion of beam of emitted electrons. Then, the electrostatic wave generated due to two-stream instability decays into multiple slower waves. Phase velocities of these waves are comparable with the thermal velocity of plasma electrons which makes possible the resonant wave-particle interaction. This results in the efficient energy deposition from emitted electrons into the plasma.
Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling
Lee, Hyo-Chang; Chung, Chin-Wook
Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics. PMID:26482650
Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling
NASA Astrophysics Data System (ADS)
Lee, Hyo-Chang; Chung, Chin-Wook
Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.
Nanoscale control of energy and matter in plasma-surface interactions: towards energy-efficient nanotech
NASA Astrophysics Data System (ADS)
Ostrikov, Kostya
This presentation focuses on the plasma issues related to the solution of the grand challenge of directing energy and matter at nanoscales. This ability is critical for the renewable energy and energy-efficient technologies for sustainable future development. It will be discussed how to use environmentally and human health benign non-equilibrium plasma-solid systems and control the elementary processes of plasma-surface interactions to direct the fluxes of energy and matter at multiple temporal and spatial scales. In turn, this makes it possible to achieve the deterministic synthesis of self- organised arrays of metastable nanostructures in the size range beyond the reach of the present-day nanofabrication. Such structures have tantalising prospects to enhance performance of nanomaterials in virtually any area of human activity yet remain almost inaccessible because the Nature's energy minimisation rules allow only a small number of stable equilibrium states. By using precisely controlled and kinetically fast nanoscale transfer of energy and matter under non-equilibrium conditions and harnessing numerous plasma- specific controls of species creation, delivery to the surface, nucleation and large-scale self-organisation of nuclei and nanostructures, the arrays of metastable nanostructures can be created, arranged, stabilised, and further processed to meet the specific requirements of the envisaged applications. These approaches will eventually lead to faster, unprecedentedly- clean, human-health-friendly, and energy-efficient nanoscale synthesis and processing technologies for the next-generation renewable energy and light sources, biomedical devices, information and communication systems, as well as advanced functional materials for applications ranging from basic food, water, health and clean environment needs to national security and space missions.
Fermilab recycler stochastic cooling commissioning and performance
D. Broemmelsiek; Ralph Pasquinelli
The Fermilab Recycler is a fixed 8 GeV kinetic energy storage ring located in the Fermilab Main Injector tunnel near the ceiling. The Recycler has two roles in Run II. First, to store antiprotons from the Fermilab Antiproton Accumulator so that the antiproton production rate is no longer compromised by large numbers of antiprotons stored in the Accumulator. Second, to receive antiprotons from the Fermilab Tevatron at the end of luminosity periods. To perform each of these roles, stochastic cooling in the Recycler is needed to preserve and cool antiprotons in preparation for transfer to the Tevatron. The commissioning and performance of the Recycler stochastic cooling systems will be reviewed.
Drosophila exocyst components Sec5, Sec6, and Sec15 regulate DE-Cadherin trafficking from recycling endosomes to the plasma membrane.
Langevin, Johanna; Morgan, Matthew J; Sibarita, Jean-Baptiste; Aresta, Sandra; Murthy, Mala; Schwarz, Thomas; Camonis, Jacques; Bellaïche, Yohanns
The E-Cadherin-catenin complex plays a critical role in epithelial cell-cell adhesion, polarization, and morphogenesis. Here, we have analyzed the mechanism of Drosophila E-Cadherin (DE-Cad) localization. Loss of function of the Drosophila exocyst components sec5, sec6, and sec15 in epithelial cells results in DE-Cad accumulation in an enlarged Rab11 recycling endosomal compartment and inhibits DE-Cad delivery to the membrane. Furthermore, Rab11 and Armadillo interact with the exocyst components Sec15 and Sec10, respectively. Our results support a model whereby the exocyst regulates DE-Cadherin trafficking, from recycling endosomes to sites on the epithelial cell membrane where Armadillo is located. PMID:16224820
INEEL Lead Recycling in a Moratorium Environment
Kooda, Kevin Evan; Mc Cray, Casey William; Aitken, Darren William; Galloway, Kelly
Since 1999, the Idaho National Engineering and Environmental Laboratory (INEEL) Lead Project successfully recycled over 700,000 pounds of excess INEEL lead to the private sector. On February 14, 2000, the Secretary of Energy, Bill Richardson, formalized the January 12, 2000, moratorium on recycling radioactive scrap metal that prevented the unrestricted release of recycled scrap metals to the private sector. This moratorium created significant problems for the INEEL lead recycling program and associated plans; however, through the cooperative efforts of the INEEL and Idaho State University as well as innovative planning and creative thinking the recycling issues were resolved. This collaboration has recycled over 160,000 pounds of excess lead to Idaho State University with a cost savings of over $.5M.
INEEL Lead Recycling in a Moratorium Environment
Kooda, K. E.; Galloway, K.; McCray, C. W.; Aitken, D. W.
Since 1999, the Idaho National Engineering and Environmental Laboratory (INEEL) Lead Project successfully recycled over 700,000 pounds of excess INEEL lead to the private sector. On February 14, 2000, the Secretary of Energy, Bill Richardson, formalized the January 12, 2000, moratorium on recycling radioactive scrap metal that prevented the unrestricted release of recycled scrap metals to the private sector. This moratorium created significant problems for the INEEL lead recycling program and associated plans; however, through the cooperative efforts of the INEEL and Idaho State University as well as innovative planning and creative thinking the recycling issues were resolved. This collaboration has recycled over 160,000 pounds of excess lead to Idaho State University with a cost savings of over $.5M.
Casimir effects for a flat plasma sheet: I. Energies
NASA Astrophysics Data System (ADS)
Barton, G.
We study a fluid model of an infinitesimally thin plasma sheet occupying the xy plane, loosely imitating a single base plane from graphite. In terms of the fluid charge e/a2 and mass m/a2 per unit area, the crucial parameters are q ⋡ 2πe2/mc2a2, a Debye-type cutoff K\\equiv \\sqrt{4\\pi }/a on surface-parallel normal-mode wavenumbers k, and X ⋡ K/q. The cohesive energy β per unit area is determined from the zero-point energies of the exact normal modes of the plasma coupled to the Maxwell field, namely TE and TM photon modes, plus bound modes decaying exponentially with |z|. Odd-parity modes (with Ex,y(z = 0) = 0) are unaffected by the sheet except for their overall phases, and are irrelevant to β, although the following paper shows that they are essential to the fields (e.g. to their vacuum expectation values), and to the stresses on the sheet. Realistically one has X Gt 1, the result β ~ planckcq1/2K5/2 is nonrelativistic, and it comes from the surface modes. By contrast, X Lt 1 (nearing the limit of perfect reflection) would entail β ~ -planckcqK2log(1/X): contrary to folklore, the surface energy of perfect reflectors is divergent rather than zero. An appendix spells out the relation, for given k, between bound modes and photon phase-shifts. It is very different from Levinson's theorem for 1D potential theory: cursory analogies between TM and potential scattering are apt to mislead.
Idea Notebook: Recycling with an Educational Purpose.
ERIC Educational Resources Information Center
Gerth, Tom; Wilson, David A.
Four students at St. Louis University High School developed a project to clean up the environment while saving energy and natural resources. Aluminum and steel cans were recycled and the money was used to buy and plant trees. Students learned about recycling, organization, money management, and improving the environment. (JMM)
Recycling Primer: Getting Back to Basics.
ERIC Educational Resources Information Center
Connecticut State Dept. of Environmental Protection, Hartford.
The disposal of garbage is a complex issue. Four strategies have been developed to attack the problem. They deal with: (1) waste reduction; (2) recycling; (3) energy recovery; and (4) land filling. This handbook emphasizes recycling as a method of handling the problem of dealing with solid wastes. Included are a list of the categories and uses of…
Recycled Art: Create Puppets Using Recycled Objects.
ERIC Educational Resources Information Center
Clearing, 2003
Presents an activity from "Healthy Foods from Healthy Soils" for making puppets using recycled food packaging materials. Includes background information, materials, instructions, literature links, resources, and benchmarks. (NB)
Recycle Used Oil on America Recycles Day.
ERIC Educational Resources Information Center
White, Boyd W.
Explains that motor oils can be reused and recycled. Educates students about environmental hazards and oil management and includes classroom activities. Addresses the National Science Education Standards. (YDS)
Energy characteristics of beam-plasma interaction in a closed volume
NASA Astrophysics Data System (ADS)
Klykov, I. L.; Tarakanov, V. P.; Shustin, E. G.
Energy exchange between an electron beam and plasma during a beam-plasma discharge in a closed cavity excited by the electron beam is analyzed using computer simulations by the KARAT code. A method allowing one to analyze the beam-plasma interaction in the quasi-steady stage of the discharge is proposed. Qualitative characteristics of energy exchange (such as beam energy losses and the energy distributions of beam electrons and plasma particles leaving the discharge) both during spontaneous discharge excitation and in the presence of initial beam modulation by regular or noiselike signals are determined. The results obtained enable one to estimate the energy characteristics of a plasma processing reactor based on a beam-plasma discharge.
Energy and matter flows in a plasma focus discharge
NASA Astrophysics Data System (ADS)
Vikhrev, V. V.; Suslin, S. V.
The Plasma Focus is a type of z-pinch that is widely used for both basic research and applied tasks, e.g., as materials modification or research on intense plasma flows. Although the basic mechanisms of z-pinch compression are well-known, many of the processes that occur in the plasma focus have received less attention. This article is devoted to the study of plasma jets and some of its consequences in plasma focus discharges.
High energy density plasma science with an ultrarelativistic electron beam
NASA Astrophysics Data System (ADS)
Joshi, C.; Blue, B.; Clayton, C. E.; Dodd, E.; Huang, C.; Marsh, K. A.; Mori, W. B.; Wang, S.; Hogan, M. J.; O'Connell, C.; Siemann, R.; Watz, D.; Muggli, P.; Katsouleas, T.; Lee, S.
An intense, high-energy electron or positron beam can have focused intensities rivaling those of today's most powerful laser beams. For example, the 5 ps (full-width, half-maximum), 50 GeV beam at the Stanford Linear Accelerator Center (SLAC) at 1 kA and focused to a 3 micron rms spot size gives intensities of >1020 W/cm-2 at a repetition rate of >10 Hz. Unlike a ps or fs laser pulse which interacts with the surface of a solid target, the particle beam can readily tunnel through tens of cm of steel. However, the same particle beam can be manipulated quite effectively by a plasma that is a million times less dense than air! This is because of the incredibly strong collective fields induced in the plasma by the Coulomb force of the beam. The collective fields in turn react back onto the beam leading to many clearly observable phenomena. The beam paraticles can be: (1) Deflected leading to focusing, defocusing, or even steering of the beam; (2) undulated causing the emission of spontaneous betatron x-ray radiation and; (3) accelerated or decelerated by the plasma fields. Using the 28.5 GeV electron beam from the SLAC linac a series of experiments have been carried out that demonstrate clearly many of the above mentioned effects. The results can be compared with theoretical predictions and with two-dimensional and three-dimensional, one-to-one, particle-in-cell code simulations. These phenomena may have practical applications in future technologies including optical elements in particle beam lines, synchrotron light sources, and ultrahigh gradient accelerators.
Environmental analysis of a construction and demolition waste recycling plant in Portugal--Part I: energy consumption and CO2 emissions.
Coelho, André; de Brito, Jorge
This work is a part of a wider study involving the economic and environmental implications of managing construction and demolition waste (CDW), focused on the operation of a large scale CDW recycling plant. This plant, to be operated in the Lisbon Metropolitan Area (including the Setúbal peninsula), is analysed for a 60 year period, using primary energy consumption and CO2eq emission impact factors as environmental impact performance indicators. Simplified estimation methods are used to calculate industrial equipment incorporated, and the operation and transport related impacts. Material recycling--sorted materials sent to other industries, to act as input--is taken into account by discounting the impacts related to industrial processes no longer needed. This first part focuses on calculating the selected impact factors for a base case scenario (with a 350 tonnes/h installed capacity), while a sensitivity analysis is provided in part two. Overall, a 60 year global primary energy consumption of 71.4 thousand toe (tonne of oil equivalent) and a total CO2eq emission of 135.4 thousand tonnes are expected. Under this operating regime, around 563 thousand toe and 1465 thousand tonnes CO2eq could be prevented by replacing raw materials in several construction materials industries (e.g.: ferrous and non-ferrous metals, plastics, paper and cardboard). PMID:23422042
THE IRON OPACITY PROJECT: High-Energy-Density Plasma Opacities
NASA Astrophysics Data System (ADS)
Palay, E.; Orban, C.; Nahar, S.; Pradhan, A.; Pinnsonoault, M.; Bailey, J.
Opacity governs radiation flow in plasma sources. Accurate opacities are needed to model unobservable laboratory and astrophysical conditions. High-energy-density (HED) plasma conditions prevalent in stellar interiors can now be recreated in the laboratory. The Z-pinch fusion device at the Sandia National Lab can reproduce temperatures and densities near the boundary where radiation transport changes from diffusion to convection inside the Sun. To benchmark theoretical opacities experiments are essential to resolve the outstanding discrepancy in solar abundances. The most common volatile elements C, N, O, Ne, etc. have been spectroscopically measured to be up to 50% lower than the standard abundances. This introduces conflict in the derived values of basic solar parameters such as the radiation/convection boundary, sound speed, and the primordial He abundance with precisely measured oscillations of the Sun through Helioseismology. A potential solution is increment of stellar opacities, which has inverse but complex relation with abundacnes, at least 30%. New iron opacity calculations include hitherto neglected atomic physics of fine structure and resonances which are largely treated as lines in existing opacities calculations. Preliminary results on radiative transitions in Ne Partial support: DOE,NSF.
Very low pressure plasma sprayed yttria-stabilized zirconia coating using a low-energy plasma gun
NASA Astrophysics Data System (ADS)
Zhu, Lin; Zhang, Nannan; Bolot, Rodolphe; Planche, Marie-Pierre; Liao, Hanlin; Coddet, Christian
In the present study, a more economical low-energy plasma source was used to perform a very low pressure plasma-spray (VLPPS) process. The plasma-jet properties were analyzed by means of optical emission spectroscopy (OES). Moreover, yttria-stabilized zirconia coating (YSZ) was elaborated by a F100 low-power plasma gun under working pressure of 1 mbar, and the substrate specimens were partially shadowed by a baffle-plate during plasma spraying for obtaining different coating microstructures. Based on the SEM observation, a column-like grain coating was deposited by pure vapor deposition at the shadowed region, whereas, in the unshadowed region, the coating exhibited a binary microstructure which was formed by a mixed deposition of melted particles and evaporated particles. The mechanical properties of the coating were also well under investigation.
Concentrating and recycling energy in lanthanide codopants for efficient and spectrally pure emission: the case of NaYF4:Er3+/Tm3+ upconverting nanocrystals.
Chan, Emory M; Gargas, Daniel J; Schuck, P James; Milliron, Delia J
In lanthanide-doped materials, energy transfer (ET) between codopant ions can populate or depopulate excited states, giving rise to spectrally pure luminescence that is valuable for the multicolor imaging and simultaneous tracking of multiple biological species. Here, we use the case study of NaYF(4) nanocrystals codoped with Er(3+) and Tm(3+) to theoretically investigate the ET mechanisms that selectively enhance and suppress visible upconversion luminescence under near-infrared excitation. Using an experimentally validated population balance model and using a path-tracing algorithm to objectively identify transitions with the most significant contributions, we isolated a network of six pathways that combine to divert energy away from the green-emitting manifolds and concentrate it in the Tm(3+):(3)F(4) manifold, which then participates in energy transfer upconversion (ETU) to populate the red-emitting Er(3+):(4)F(9/2) manifold. We conclude that the strength of this ETU process is a function of the strong coupling of the Tm(3+):(3)F(4) manifold and its ground state, the near-optimum band alignment of Er(3+) and Tm(3+) manifolds, and the concentration of population in Tm(3+):(3)F(4). These factors, along with the ability to recycle energy not utilized for red emission, also contribute to the enhanced quantum yield of NaYF(4):Er(3+)/Tm(3+). We generalize a scheme for applying these energy concentration and recycling pathways to other combinations of lanthanide dopants. Ultimately, these ET pathways and others elucidated by our theoretical modeling will enable the programming of physical properties in lanthanide-doped materials for a variety of applications that demand strong and precisely defined optical transitions. PMID:22551408
Professor Bruce R. Kusse; Professor David A. Hammer
This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.
Surface energy increase of oxygen-plasma-treated PET
Cioffi, M.O.H.; Voorwald, H.J.C.; Mota, R.P
Prosthetic composite is a widely used biomaterial that satisfies the criteria for application as an organic implant without adverse reactions. Polyethylene therephthalate (PET) fiber-reinforced composites have been used because of the excellent cell adhesion, biodegradability and biocompatibility. The chemical inertness and low surface energy of PET in general are associated with inadequate bonds for polymer reinforcements. It is recognized that the high strength of composites, which results from the interaction between the constituents, is directly related to the interfacial condition or to the interphase. A radio frequency plasma reactor using oxygen was used to treat PET fibers for 5, 20, 30 and 100 s. The treatment conditions were 13.56 MHz, 50 W, 40 Pa and 3.33x10{sup -7} m{sup 3}/s. A Rame-Hart goniometer was used to measure the contact angle and surface energy variation of fibers treated for different times. The experimental results showed contact angle values from 47 deg. to 13 deg. and surface energies from 6.4x10{sup -6} to 8.3x10{sup -6} J for the range of 5 to 100 s, respectively. These results were confirmed by the average ultimate tensile strength of the PET fiber/ polymethylmethacrylate (PMMA) matrix composite tested in tensile mode and by scanning electron microscopy.
Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas
Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook
The total energy lost per electron-ion pair lost ε{sub T} is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ε{sub T} is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ε{sub T} from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ε{sub T} from the depleted EEDFs has a value that is similar to the measured ε{sub T}.
Effect of the electron energy distribution on total energy loss with argon in inductively coupled plasmas
NASA Astrophysics Data System (ADS)
Kim, June Young; Kim, Young-Cheol; Kim, Yu-Sin; Chung, Chin-Wook
The total energy lost per electron-ion pair lost ɛT is investigated with the electron energy distribution function (EEDF). The EEDFs are measured at various argon powers in RF inductively coupled plasma, and the EEDFs show a depleted distribution (a discontinuity occurring at the minimum argon excitation threshold energy level) with the bulk temperature and the tail temperature. The total energy loss per electron-ion pair lost ɛT is calculated from a power balance model with the Maxwellian EEDFs and the depleted EEDFs and then compared with the measured ɛT from the floating probe. It is concluded that the small population of the depleted high energy electrons dramatically increases the collisional energy loss, and the calculated ɛT from the depleted EEDFs has a value that is similar to the measured ɛT.
Reverse Energy Cascade in Turbulent Weakly Ionized Plasmas
NASA Technical Reports Server (NTRS)
Williams, Kyron; Appartaim, R.; Belay, K.; Johnson, J. A., III
For systems far from equilibrium, the neglect of a role for viscous effects in turbulence may be generally inappropriate when the relaxation time for the molecular process approaches the local flow time (Orou et al. (1996)). Furthermore, for stationary collisional plasmas, the conventional Reynolds number is irrelevant under circumstances where the standard features of turbulence in ordinary gases are observed in the plasma (Johnson et al. (1987)). The current theoretical understanding of these turbulent phenomenon is particularly inadequate for turbulence associated with ionizing shock waves; generally speaking, thermodynamic, acoustic and pressure fluctuations are all seen as amplified across the shock wave followed by a dramatic decay (relaminarization) usually attributed to a lack of importance of viscosity in the turbulent regions. This decay would be accelerated when the flow speed is also reduced due to the importance usually given to the conventional Reynolds number (which is directly proportional to velocity) as a quality of turbulence index. However, evidence supporting this consensus is lacking. By contrast, recent evidence of vanishing triple correlations form De Silva et al. (1996) provides strong support for early theoretical speculation of inherently molecular effects in macroscopic turbulence in Tsuge (1974). This specifically suggests that the role of compressive effects ordinarily associated with the shock wave could be significantly muted by the existence of a strongly turbulent local environment. There is also more recent theoretical speculation (Frisch et al. (1984)) of an inherently and previously unsuspected non-dissipative nature to turbulence, with energy conservation being nurtured by reverse energy cascades in the turbulent fluctuation spectra. Furthermore, the role which might be played by fluctuations on quantum mechanical phenomena and variations in molecular parameters is completely unknown, especially of the sort which might be found
A burning plasma program strategy to advance fusion energy. Report of the Fusion Energy Sciences Advisory Committee, Burning Plasma Strategy Panel
None, None
Fusion energy shows great promise to contribute to securing the energy future of humanity. The risk of conflicts arising from energy shortages and supply cutoffs, as well as the risk of severe environmental impacts from existing methods of energy production, are strong reasons to pursue fusion energy now. The world effort to develop fusion energy is at the threshold of a new stage in its research: the investigation of burning plasmas. This investigation, at the frontier of the physics of complex systems, would be a huge step in establishing the potential of magnetic fusion energy to contribute to the world's energy security. The defining feature of a burning plasma is that it is self-heated: the 100 million degree temperature of the plasma is maintained mainly by the heat generated by the fusion reactions themselves, as occurs in burning stars. The fusion-generated alpha particles produce new physical phenomena that are strongly coupled together as a nonlinear complex system. Understanding all elements of this system poses a major challenge to fundamental plasma physics. The technology needed to produce and control a burning plasma presents challenges in engineering science similarly essential to the development of fusion energy.
Recycling production designs: the value of coordination and flexibility in aluminum recycling operations
NASA Astrophysics Data System (ADS)
Brommer, Tracey H.
The growing motivation for aluminum recycling has prompted interest in recycling alternative and more challenging secondary materials. The nature of these alternative secondary materials necessitates the development of an intermediate recycling facility that can reprocess the secondary materials into a liquid product Two downstream aluminum remelters will incorporate the liquid products into their aluminum alloy production schedules. Energy and environmental benefits result from delivering the products as liquid but coordination challenges persist because of the energy cost to maintain the liquid. Further coordination challenges result from the necessity to establish a long term recycling production plan in the presence of long term downstream aluminum remelter production uncertainty and inherent variation in the daily order schedule of the downstream aluminum remelters. In this context a fundamental question arises, considering the metallurgical complexities of dross reprocessing, what is the value of operating a coordinated set of by-product reprocessing plants and remelting cast houses? A methodology is presented to calculate the optimal recycling center production parameters including 1) the number of recycled products, 2) the volume of recycled products, 3) allocation of recycled materials across recycled products, 4) allocation of recycled products across finished alloys, 4) the level of flexibility for the recycling center to operate. The methods implemented include, 1) an optimization model to describe the long term operations of the recycling center, 2) an uncertainty simulation tool, 3) a simulation optimization method, 4) a dynamic simulation tool with four embedded daily production optimization models of varying degrees of flexibility. This methodology is used to quantify the performance of several recycling center production designs of varying levels of coordination and flexibility. This analysis allowed the identification of the optimal recycling
Not Available
This article discusses the recycling programs currently in use in Sweden. Recycling of newspapers, batteries, plastics are all mentioned in this report by the Swedish Association of Public Cleansing and Solid Waste Management.
Recycling Research. Tracking Trash.
ERIC Educational Resources Information Center
DeLago, Louise Furia
An activity in which students research the effectiveness of recycling is presented. Students compare the types and amount of litter both before and after recycling is implemented. Directions for the activity and a sample data sheet are included. (KR)
Recyclable transmission line (RTL) and linear transformer driver (LTD) development for Z-pinch inertial fusion energy (Z-IFE) and high yield.
Sharpe, Robin Arthur; Kingsep, Alexander S. (Kurchatov Institute, Moscow, Russia); Smith, David Lewis; Olson, Craig Lee; Ottinger, Paul F. (Naval Research Laboratory, Washington, DC); Schumer, Joseph Wade (Naval Research Laboratory, Washington, DC); Welch, Dale Robert (Voss Scientific, Albuquerque, NM); Kim, Alexander (High Currents Institute, Tomsk, Russia); Kulcinski, Gerald L. (University of Wisconsin, Madison, WI); Kammer, Daniel C. (University of Wisconsin, Madison, WI); Rose, David Vincent (Voss Scientific, Albuquerque, NM); Nedoseev, Sergei L. (Kurchatov Institute, Moscow, Russia); Pointon, Timothy David; Smirnov, Valentin P.; Turgeon, Matthew C.; Kalinin, Yuri G. (Kurchatov Institute, Moscow, Russia); Bruner, Nichelle "Nicki" (Voss Scientific, Albuquerque, NM); Barkey, Mark E. (University of Alabama, Tuscaloosa, AL); Guthrie, Michael (University of Wisconsin, Madison, WI); Thoma, Carsten (Voss Scientific, Albuquerque, NM); Genoni, Tom C. (Voss Scientific, Albuquerque, NM); Langston, William L.; Fowler, William E.; Mazarakis, Michael Gerrassimos
Z-Pinch Inertial Fusion Energy (Z-IFE) complements and extends the single-shot z-pinch fusion program on Z to a repetitive, high-yield, power plant scenario that can be used for the production of electricity, transmutation of nuclear waste, and hydrogen production, all with no CO{sub 2} production and no long-lived radioactive nuclear waste. The Z-IFE concept uses a Linear Transformer Driver (LTD) accelerator, and a Recyclable Transmission Line (RTL) to connect the LTD driver to a high-yield fusion target inside a thick-liquid-wall power plant chamber. Results of RTL and LTD research are reported here, that include: (1) The key physics issues for RTLs involve the power flow at the high linear current densities that occur near the target (up to 5 MA/cm). These issues include surface heating, melting, ablation, plasma formation, electron flow, magnetic insulation, conductivity changes, magnetic field diffusion changes, possible ion flow, and RTL mass motion. These issues are studied theoretically, computationally (with the ALEGRA and LSP codes), and will work at 5 MA/cm or higher, with anode-cathode gaps as small as 2 mm. (2) An RTL misalignment sensitivity study has been performed using a 3D circuit model. Results show very small load current variations for significant RTL misalignments. (3) The key structural issues for RTLs involve optimizing the RTL strength (varying shape, ribs, etc.) while minimizing the RTL mass. Optimization studies show RTL mass reductions by factors of three or more. (4) Fabrication and pressure testing of Z-PoP (Proof-of-Principle) size RTLs are successfully reported here. (5) Modeling of the effect of initial RTL imperfections on the buckling pressure has been performed. Results show that the curved RTL offers a much greater buckling pressure as well as less sensitivity to imperfections than three other RTL designs. (6) Repetitive operation of a 0.5 MA, 100 kV, 100 ns, LTD cavity with gas purging between shots and automated operation is
Energy branching in the Io plasma torus - The failure of neutral cloud theory
NASA Technical Reports Server (NTRS)
Shemansky, D. E.
Model calculations are used to explore the energy source characteristics of the energy branching of the hot Io plasma torus. It is assumed that the energy is derived from the kinetic energy acquired by ions created in the rotating planetary magnetic field, and that Coulomb collisions with the electron gas control the flow of energy to the ionizing and radiative processes. The results show that neutral cloud theory is qualitatively inadequate. It is shown that neutral cloud theory can only support a dominantly singly ionized system (at the measured electron densities in the plasma torus) and that it fails to predict observed plasma properties relative to variations in number density.
Radioactive materials in recycled metals.
Lubenau, J O; Yusko, J G
In recent years, the metal recycling industry has become increasingly aware of an unwanted component in metal scrap--radioactive material. Worldwide, there have been 35 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. In at least one case, serious radiation exposures of workers and the public occurred. Radioactive material appearing in metal scrap includes sources subject to licensing under the Atomic Energy Act and also naturally occurring radioactive material. U.S. mills that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each event. To solve the problem, industry and the government have jointly undertaken initiatives to increase awareness of the problem within the metal recycling industry. Radiation monitoring of recycled metal scrap is being performed increasingly by mills and, to a lesser extent, by scrap processors. The monitoring does not, however, provide 100% protection. Improvements in regulatory oversight by the government could stimulate improved accounting and control of licensed sources. However, additional government effort in this area must be reconciled with competing priorities in radiation safety and budgetary constraints. The threat of radioactive material in recycled metal scrap will continue for the foreseeable future and, thus, poses regulatory policy challenges for both developed and developing nations. PMID:7883556
Hall, L.S.
A method of heating a plasma confined by a static magnetic field is presented. A time-varying magnetic field having a rise time to a predetermined value substantially less than its fall time is applied to a portion of the plasma. Because of the much shorter rise time, the plasma is reversibly heated. This cycle is repeated until the desired plasma temperature is reached. (AEC)
Automotive shredder residue (ASR): reviewing its production from end-of-life vehicles (ELVs) and its recycling, energy or chemicals' valorisation.
Vermeulen, I; Van Caneghem, J; Block, C; Baeyens, J; Vandecasteele, C
ASR is in Europe classified as hazardous waste. Both the stringent landfill legislation and the objectives/legislation related to ELV treatment of various countries, will limit current landfilling practice and impose an increased efficiency of the recovery and recycling of ELVs. The present paper situates ASR within the ELV context. Primary recovery techniques recycle up to 75% of the ELV components; the remaining 25% is called ASR. Characteristics of ASR and possible upgrading by secondary recovery techniques are reviewed. The latter techniques can produce a fuel- or fillergrade ASR, however with limitations as discussed. A further reduction of ASR to be disposed of calls upon (co-)incineration or the use of thermo-chemical processes, such as pyrolysis or gasification. The application in waste-to-energy plants, in cement kilns or in metallurgical processes is possible, with attention to the possible environmental impact: research into these impacts is discussed in detail. Pyrolysis and gasification are emerging technologies: although the sole use of ASR is debatable, its mixing with other waste streams is gradually being applied in commercial processes. The environmental impacts of the processes are acceptable, but more supporting data are needed and the advantage over (co-)incineration remains to be proven. PMID:21440364
Determining the electron energy distribution near the plasma potential in the earth's ionosphere
NASA Technical Reports Server (NTRS)
Sharp, W. E.; Hays, P. B.; Cutler, J. R.; Dobbs, M. E.
A determination of the plasma potential using an electrostatic analyzer is described in which the potential difference between the instrument slit system and surrounding plasma is minimized. Data obtained from rocket-borne instrumentation demonstrate the viability of this technique for electron fluxes between thermal energies (about 0.5 V) and suprathermal energies (many volts).
Holt, D.J.
This article examines the current status of automobile recycling and contains a summary of a survey which points out the major drivers and their impacts on automotive recycling. The topics of the article include computerized dismantling, polyurethane, sheet molding compound, polyester, thermoplastic polyester, recycling salvaged parts, vinyl and automotive shredder residue.
The Sustainability of Recycling.
ERIC Educational Resources Information Center
Juniper, Christopher
Describes the need for closing the business cycle in the recycling process. Discusses whether the government should mandate or the free market create uses for recycled products. Presents challenges associated with marketing recycled materials including what has been and what needs to be done to stimulate markets, encourage business, and balance…
ERIC Educational Resources Information Center
Wrhen, Linda; DiSpezio, Michael A.
Information about the recycling and reuse of plastics, aluminum, steel, glass, and newspapers is presented. The phases of recycling are described. An activity that allows students to separate recyclable materials is included. The objectives, a list of needed materials, and procedure are provided. (KR)
Rapid recycling of ClC-2 chloride channels between plasma membrane and endosomes: role of a tyrosine endocytosis motif in surface retrieval.
Cornejo, Isabel; Niemeyer, María Isabel; Zúñiga, Leandro; Yusef, Yamil R; Sepúlveda, Francisco V; Cid, L Pablo
ClC-2 chloride channel is present in the brain and some transporting epithelia where its function is poorly understood. We have now demonstrated that the surface channels are rapidly internalised and approximately the 70% of the surface membrane protein recycles after 4- to 8-min internalisation. Endocytosis of ClC-2 was dependent upon tyrosine 179 located within an endocytic motif. Rapid recycling accompanied by an even faster internalisation could account for the abundant presence of ClC-2 in intracellular membranous structures. At least a proportion of ClC-2 resides in lipid rafts. Use of beta-cyclodextrin led to an increase in cell surface channel, but, surprisingly, a decrease in functionally active channels. We suggest that ClC-2 requires residing in beta-cyclodextrin sensitive clusters with other molecules in order to remain active. Regulation of ClC-2 trafficking to and within the membrane could be a means of modulating its activity. PMID:19711355
Enhancing the Efficiency and Contrast Ratio of White Organic Light-Emitting Diode Using Energy-Recyclable Photovoltaic Cells
NASA Astrophysics Data System (ADS)
Yokoyama, Meiso; Wu, Chung-Ming; Su, Shui-Hsiang
We demonstrate that power recycling is feasible by using a semitransparent strip of Al electrode as an interconnecting layer to merge a white organic light-emitting device (WOLED) and an organic photovoltaic (OPV) cell. The device is called a photovoltaic organic light-emitting device (PVOLED). It has a glass/indium tin oxide (ITO)/copper phthalocyanine (CuPc)/4,4,4-tris(3-methyl-phenylphenylamino) triphenylamine (m-MTDATA):V2O5/2-N',N-bis(1-naphthyl)-N,N'-diphenyl-1'-biphenyl-4,4'-diamine (NPB)/4,4'-bis(carbazol-9-yl)biphenyl (CBP):bis[3,5-difluoro-2-(2-pyridyl) phenyl-(2-carboxypyridyl)] iridium(II) (FIrpic):4-(dicyanomethylene)-2-t-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB)/4,7-diphenyl-1,10-phenanthroline (BPhen)/LiF/Al/poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61 butyric acid methyl ester (PCBM)/V2O5/Al structure. A power recycling efficiency of 10.133% is achieved using the WOLED of the PVOLED operated at 9 V and a brightness of 2110 cd/m2 when the conversion efficiency of the OPV cell is 2.3%. We found that the power recycling efficiency decreases at a high brightness and a high applied voltage owing to an increase in the input power of the WOLED. A high efficiency (18.3 cd/A) and a high contrast ratio (9.3) are obtained in the device operated at 2500 cd/m2 under an ambient illumination of 24000 lx. Reasonable white light emission with Commission Internationale De L'Eclairage (CIE) color coordinates of (0.32, 0.44) at 20 mA/cm2 and a slight color shift occur in spite of the high current density of 50 mA/cm2.
Highly flexible binder-free core–shell nanofibrous electrode for lightweight electrochemical energy storage using recycled water bottles
NASA Astrophysics Data System (ADS)
Shi, HaoTian H.; Naguib, Hani E.
The creation of a novel flexible nanocomposite fiber with conductive polymer polyaniline (PAni) coating on a polyethylene terephthalate (PET) substrate allowed for increased electrochemical performance while retaining ideal mechanical properties such as very high flexibility. Binder-free PAni-wrapped PET (PAni@PET) fiber with a core–shell structure was successfully fabricated through a novel technique. The PET nanofiber substrate was fabricated through an optimized electrospinning method, while the PAni shell was chemically polymerized onto the surface of the nanofibers. The PET substrate can be made directly from recycled PETE1 grade plastic water bottles. The resulting nanofiber with an average diameter of 121 nm ± 39 nm, with a specific surface area of 83.72 m2 g‑1, led to better ionic interactions at the electrode/electrolyte interface. The PAni active layer coating was found to be 69 nm in average thickness. The specific capacitance was found to have increased dramatically from pure PAni with carbon binders. The specific capacitance was found to be 347 F g‑1 at a relatively high scan rate of 10 mV s‑1. The PAni/PET fiber also experienced very little degradation (4.4%) in capacitance after 1500 galvanostatic charge/discharge cycles at a specific current of 1.2 A g‑1. The mesoporous structure of the PAni@PET fibrous mat also allowed for tunable capacitance by controlling the pore sizes. This novel fabrication method offers insights for the utilization of recycled PETE1 based bottles as a high performance, low cost, highly flexible supercapacitor device.
Highly flexible binder-free core-shell nanofibrous electrode for lightweight electrochemical energy storage using recycled water bottles.
Shi, HaoTian H; Naguib, Hani E
The creation of a novel flexible nanocomposite fiber with conductive polymer polyaniline (PAni) coating on a polyethylene terephthalate (PET) substrate allowed for increased electrochemical performance while retaining ideal mechanical properties such as very high flexibility. Binder-free PAni-wrapped PET (PAni@PET) fiber with a core-shell structure was successfully fabricated through a novel technique. The PET nanofiber substrate was fabricated through an optimized electrospinning method, while the PAni shell was chemically polymerized onto the surface of the nanofibers. The PET substrate can be made directly from recycled PETE1 grade plastic water bottles. The resulting nanofiber with an average diameter of 121 nm ± 39 nm, with a specific surface area of 83.72 m(2) g(-1), led to better ionic interactions at the electrode/electrolyte interface. The PAni active layer coating was found to be 69 nm in average thickness. The specific capacitance was found to have increased dramatically from pure PAni with carbon binders. The specific capacitance was found to be 347 F g(-1) at a relatively high scan rate of 10 mV s(-1). The PAni/PET fiber also experienced very little degradation (4.4%) in capacitance after 1500 galvanostatic charge/discharge cycles at a specific current of 1.2 A g(-1). The mesoporous structure of the PAni@PET fibrous mat also allowed for tunable capacitance by controlling the pore sizes. This novel fabrication method offers insights for the utilization of recycled PETE1 based bottles as a high performance, low cost, highly flexible supercapacitor device. PMID:27354434
Energy Loss of a High Charge Bunched Electron Beam in Plasma: Nonlinear Plasma Response and Linear Scaling
NASA Astrophysics Data System (ADS)
Rosenzweig, J. B.; Barov, N.; Thompson, M. C.; Yoder, R.
There has been much experimental and theoretical interest in blowout regime of plasma wakefield acceleration (PWFA), which features ultra-high accelerating fields, linear transverse focusing forces, and nonlinear plasma motion. Using an exact analysis, we examine here a fundamental limit of nonlinear PWFA excitation, by an infinitesimally short, relativistic electron beam. The beam energy loss in this case is shown to be linear in charge even for nonlinear plasma response, where a normalized, unitless charge exceeds unity, and relativistic plasma effects become important or dominant. The physical bases for this persistence of linear response are pointed out. As a byproduct of our analysis, we re-examine the issue of field divergence as the point-charge limit is approached, suggesting an important modification of commonly held views of evading unphysical energy loss. Deviations from linear behavior are investigated using simulations with finite length beams. The peak accelerating field in the plasma wave excited behind a finite-length beam is also examined, with the artifact of wave spiking adding to the apparent persistence of linear scaling of the peak field amplitude well into the nonlinear regime. On the other hand, at large enough normalized charge, linear scaling of fields collapses, with serious consequences for plasma wave excitation efficiency. The dramatic implications of these results for observing the collapse of linear scaling in planned experiments are discussed.
Transition Region Emission and the Energy Input to Thermal Plasma in Solar Flares
NASA Technical Reports Server (NTRS)
Holman, Gordon D.; Holman, Gordon D.; Dennis, Brian R.; Haga, Leah; Raymond, John C.; Panasyuk, Alexander
Understanding the energetics of solar flares depends on obtaining reliable determinations of the energy input to flare plasma. X-ray observations of the thermal bremsstrahlung from hot flare plasma provide temperatures and emission measures which, along with estimates of the plasma volume, allow the energy content of this hot plasma to be computed. However, if thermal energy losses are significant or if significant energy goes directly into cooler plasma, this is only a lower limit on the total energy injected into thermal plasma during the flare. We use SOHO UVCS observations of O VI flare emission scattered by coronal O VI ions to deduce the flare emission at transition region temperatures between 100,000 K and 1 MK for the 2002 July 23 and other flares. We find that the radiated energy at these temperatures significantly increases the deduced energy input to the thermal plasma, but by an amount that is less than the uncertainty in the computed energies. Comparisons of computed thermal and nonthermal electron energies deduced from RHESSI, GOES, and UVCS are shown.
Characterization of plasma chemistry and ion energy in cathodic arc plasma from Ti-Si cathodes of different compositions
Eriksson, A. O.; Zhirkov, I.; Dahlqvist, M.; Jensen, J.; Hultman, L.; Rosen, J.
Arc plasma from Ti-Si compound cathodes with up to 25 at. % Si was characterized in a DC arc system with respect to chemistry and charge-state-resolved ion energy. The plasma ion composition showed a lower Si content, diverging up to 12 at. % compared to the cathode composition, yet concurrently deposited films were in accordance with the cathode stoichiometry. Significant contribution to film growth from neutrals is inferred besides ions, since the contribution from macroparticles, estimated by scanning electron microscopy, cannot alone account for the compositional difference between cathode, plasma, and film. The average ion charge states for Ti and Si were higher than reference data for elemental cathodes. This result is likely related to TiSi{sub x} phases of higher cohesive energies in the compound cathodes and higher effective electron temperature in plasma formation. The ion energy distributions extended up to {approx}200 and {approx}130 eV for Ti and Si, respectively, with corresponding average energies of {approx}60 and {approx}30 eV. These averages were, however, not dependent on Si content in the cathode, except for 25 at. % Si where the average energies were increased up to 72 eV for Ti and 47 eV for Si.
Atomic Oxygen Durability Evaluation of Protected Polymers Using Thermal Energy Plasma Systems
NASA Technical Reports Server (NTRS)
Banks, Bruce A.; Rutledge, Sharon K.; Degroh, Kim K.; Stidham, Curtis R.; Gebauer, Linda; Lamoreaux, Cynthia M.
The durability evaluation of protected polymers intended for use in low Earth orbit (LEO) has necessitated the use of large-area, high-fluence, atomic oxygen exposure systems. Two thermal energy atomic oxygen exposure systems which are frequently used for such evaluations are radio frequency (RF) plasma ashers and electron cyclotron resonance plasma sources. Plasma source testing practices such as ample preparation, effective fluence prediction, atomic oxygen flux determination, erosion measurement, operational considerations, and erosion yield measurements are presented. Issues which influence the prediction of in-space durability based on ground laboratory thermal energy plasma system testing are also addressed.
Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET
NASA Astrophysics Data System (ADS)
Riccardo, V.; Loarte, A.; JET EFDA Contributors
In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target.
Measurements of low-energy electron reflection at a plasma boundary
Demidov, V. I.; Adams, S. F.; Kaganovich, I. D.; Koepke, M. E.; Kurlyandskaya, I. P.
It is demonstrated that low-energy (<3 eV) electron reflection from a solid surface in contact with a low-temperature plasma can have significant variation with time. An uncontaminated, i.e., "clean," metallic surface (just after heating up to glow) in a plasma environment may have practically no reflection of low-energy incident electrons. However, a contaminated, i.e., "dirty," surface (in some time after cleaning by heating) that has a few monolayers of absorbent can reflect low-energy incident electrons and therefore significantly affect the net electron current collected by the surface. This effect may significantly change plasma properties and should be taken into account in plasma experiments and models. A diagnostic method is demonstrated for measurements of low-energy electron absorption coefficient in plasmas with a mono-energetic electron group.
Preconceptual Design Description for Caustic Recycle Facility
Sevigny, Gary J.; Poloski, Adam P.; Fountain, Matthew S.; Kurath, Dean E.
The U.S. Department of Energy plans to vitrify both high-level and low-activity waste at the Hanford Site in southeastern Washington State. One aspect of the planning includes a need for a caustic recycle process to separate sodium hydroxide for recycle. Sodium is already a major limitation to the waste-oxide loading in the low-activity waste glass to be vitrified at the Waste Treatment Plant, and additional sodium hydroxide will be added to remove aluminum and to control precipitation in the process equipment. Aluminum is being removed from the high level sludge to reduce the number of high level waste canisters produced. A sodium recycle process would reduce the volume of low-activity waste glass produced and minimize the need to purchase new sodium hydroxide, so there is a renewed interest in investigating sodium recycle. This document describes an electrochemical facility for recycling sodium for the WTP.
Reduction of Argon Consumption to Less than 2 L min(-1) by Gas Recycling in Inductively Coupled Plasma Optical Emission Spectrometry.
Tirk, Paul; Wolfgang, Matthias; Wiltsche, Helmar
An innovative interface between the torch and the entrance optics for inductively coupled plasma optical emission spectrometry (ICP-OES) is proposed. This system is capable of collecting all argon which was initially supplied to the torch, cooling and cleaning it and feeding most of the argon back to the outer gas port of the torch. Thereby, the total argon consumption could be reduced from 14 to 1.4 L min(-1) using a standard torch and without restricting the rf power. The excitation- and rotational temperature of the plasma were identical when comparing the traditional setup with the enclosed plasma interface. However, the limits of detection (LOD) and limits of quantification (LOQ) of 27 elements investigated were degraded about 5-fold, though this fact can be expected to stem from a change of the observed zone in the plasma caused by the slight overpressure of 2000 Pa within the interface. Though the enclosed plasma interface was located close to the load coil, the rf power coupled to the interface was well below 1 W and no rf arcing was observed for two different rf generator designs. PMID:27306111
Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma.
Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M; Myers, Clayton E
Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first time in a well-defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step towards resolving one of the most important problems in plasma physics. PMID:25205135
Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma
Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.
Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first time in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.
Conversion of magnetic energy in the magnetic reconnection layer of a laboratory plasma
Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.
Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy. Despite the long history of reconnection research, how this energy conversion occurs remains a major unresolved problem in plasma physics. Here we report that the energy conversion in a laboratory reconnection layer occurs in a much larger region than previously considered. The mechanisms for energizing plasma particles in the reconnection layer are identified, and a quantitative inventory of the converted energy is presented for the first timemore » in a well defined reconnection layer; 50% of the magnetic energy is converted to particle energy, 2/3 of which transferred to ions and 1/3 to electrons. Our results are compared with simulations and space measurements, for a key step toward resolving one of the most important problems in plasma physics.« less
Plasma-Surface Interactions and Impact on Electron Energy Distribution Function
NASA Astrophysics Data System (ADS)
Fox-Lyon, N. A.; Oehrlein, G. S.; Ning, N.; Graves, D. B.; Godyak, V.
The goal of this work is to explore the role of surface processes in influencing characteristic electron energy distribution functions (EEDF).As a model system, we use a well characterized, inductively coupled plasma system to examine Ar/H2 (or D2) discharges interacting with a-C:H films. The modification/erosion of a-C:H surfaces is monitored in real time by ellipsometry and the effects of gas mixtures and surface generated carbon on plasma parameters (Te, plasma density, EEDF) are probed with Langmuir probe measurements. We find that plasma density decreased greatly (from 1011 to 109 per cm3) with small H2 additions to Ar plasma (conditions: 10-30 mTorr, 300-600 W source power). The electron temperature was shown to increase with H2 flow. At high H2 flows, the electron energy distribution transitions from Maxwellian distribution to a two-temperature distribution. The addition of 1-20 % CH4 into H2 plasma shows an increase in plasma density and a change in the electron temperature. The hydrocarbon erosion products of a-C:H films in H2 plasma are found to cause a similar effect on plasma properties as CH4 addition. These observations indicate that prediction/control of EEDF for plasmas interacting with reactive bounding surfaces requires an understanding of the consequences of the plasma-surface interactions.
Energy deposition into heavy gas plasma via pulsed inductive theta-pinch
NASA Astrophysics Data System (ADS)
Pahl, Ryan Alan
The objective of this research is to study the formation processes of a pulsed inductive plasma using heavy gases, specifically the coupling of stored capacitive energy into plasma via formation in a theta pinch coil. To aid in this research, the Missouri Plasmoid Experiment Mk. I (and later Mk. II) was created. In the first paper, the construction of differential magnetic field probes are discussed. The effects of calibration setup on B-dot probes is studied using a Helmholtz coil driven by a vector network analyzer and a pulsed-power system. Calibration in a pulsed-power environment yielded calibration factors at least 9.7% less than the vector network analyzer. In the second paper, energy deposition into various gases using a pulsed inductive test article is investigated. Experimental data are combined with a series RLC model to quantify the energy loss associated with plasma formation in Argon, Hydrogen, and Xenon at pressures from 10-100 mTorr. Plasma resistance is found to vary from 25.8-51.6 mΩ and plasma inductance varies from 41.3--47.0 nH. The greatest amount of initial capacitively stored energy that could be transferred to the plasma was 6.4 J (8.1%) of the initial 79.2 +/- 0.1 J. In the third paper, the effects of a DC preionization source on plasma formation energy is studied. The preionization source radial location is found to have negligible impact on plasma formation repeatability while voltage is found to be critical at low pressures. Without preionization, plasma formation was not possible. At 20 mTorr, 0.20 W of power was sufficient to stabilize plasma formation about the first zero-crossing of the discharge current. Increasing power to 1.49 W increased inductively coupled energy by 39%. At 200 mTorr, 4.3 mW was sufficient to produce repeatable plasma properties.
Energy density dependence of hydrogen combustion efficiency in atmospheric pressure microwave plasma
Yoshida, T.; Ezumi, N.; Sawada, K.; Tanaka, Y.; Tanaka, M.; Nishimura, K.
The recovery of tritium in nuclear fusion plants is a key issue for safety. So far, the oxidation procedure using an atmospheric pressure plasma is expected to be part of the recovery method. In this study, in order to clarify the mechanism of hydrogen oxidation by plasma chemistry, we have investigated the dependence of hydrogen combustion efficiency on gas flow rate and input power in the atmospheric pressure microwave plasma. It has been found that the combustion efficiency depends on energy density of absorbed microwave power. Hence, the energy density is considered as a key parameter for combustion processes. Also neutral gas temperatures inside and outside the plasma were measured by an optical emission spectroscopy method and thermocouple. The result shows that the neutral gas temperature in the plasma is much higher than the outside temperature of plasma. The high neutral gas temperature may affect the combustion reaction. (authors)
Understanding of Edge Plasmas in Magnetic Fusion Energy Devices
Rognlien, T
A limited overview is given of the theoretical understanding of edge plasmas in fusion devices. This plasma occupies the thin region between the hot core plasma and material walls in magnetically confinement configurations. The region is often formed by a change in magnetic topology from close magnetic field lines (i.e., the core region) and open field lines that contact material surfaces (i.e., the scrape-off layer [SOL]), with the most common example being magnetically diverted tokamaks. The physics of this region is determined by the interaction of plasma with neutral gas in the presence of plasma turbulence, with impurity radiation being an important component. Recent advances in modeling strong, intermittent micro-turbulent edge-plasma transport is given, and the closely coupled self-consistent evolution of the edge-plasma profiles in tokamaks. In addition, selected new results are given for the characterization of edge-plasmas behavior in the areas of edge-pedestal relaxation and SOL transport via Edge-Localize Modes (ELMs), impurity formation including dust, and magnetic field-line stochasticity in tokamaks.
Post, R.F.
An apparatus is described for controlling electron temperature in plasma confined in a Pyrotron magnetic containment field. Basically the device comprises means for directing low temperature electrons to the plasma in controlled quantities to maintain a predetermined optimum equilibrium electron temperature whereat minimum losses of plasma ions due to ambipolar effects and energy damping of the ions due to dynamical friction with the electrons occur. (AEC)
Energy enhancement of proton acceleration in combinational radiation pressure and bubble by optimizing plasma density
Bake, Muhammad Ali; Xie Baisong; Shan Zhang; Hong Xueren; Wang Hongyu
The combinational laser radiation pressure and plasma bubble fields to accelerate protons are researched through theoretical analysis and numerical simulations. The dephasing length of the accelerated protons bunch in the front of the bubble and the density gradient effect of background plasma on the accelerating phase are analyzed in detail theoretically. The radiation damping effect on the accelerated protons energy is also considered. And it is demonstrated by two-dimensional particle-in-cell simulations that the protons bunch energy can be increased by using the background plasma with negative density gradient. However, radiation damping makes the maximal energy of the accelerated protons a little reduction.
Numerical simulation of the plasma current quench following a disruptive energy loss
Strickler, D.J.; Peng, Y.K.M.; Holmes, J.A.; Miller, J.B.; Rothe, K.E.
The plasma electromagnetic interaction with poloidal field coils and nearby passive conductor loops during the current quench following a disruptive loss of plasma energy is simulated. By solving a differential/algebraic system consisting of a set of circuit equations (including the plasma circuit) coupled to a plasma energy balance equation and an equilibrium condition, the electromagnetic consequences of an abrupt thermal quench are observed. Limiters on the small and large major radium sides of the plasma are assumed to define the plasma cross section. The presence of good conductors near the plasma and a small initial distance (i.e., 5 to 10% of the plasma minor radius) between the plasma edge and an inboard limiter are shown to lead to long current decay times. For a plasma with an initial major radius R/sub o/ = 4.3 m, aspect ratio A = 3.6, and current I/sub P/ = 4.0 MA, introducing nearby passive conductors lengthens the current decay from milliseconds to hundreds of milliseconds.
Plasma Physics Regimes in Tokamaks with Li Walls
L.E. Zakharo; N.N. Gorelenkov; R.B. White; S.I. Krasheninnikov; G.V. Pereverzev
Low recycling regimes with a plasma limited by a lithium wall surface suggest enhanced stability and energy confinement, both necessary for tokamak reactors. These regimes could make ignition feasible in compact tokamaks. Ignited Spherical Tokamaks (IST), self-sufficient in the bootstrap current, are introduced as a necessary step for development of the physics and technology of power reactors.
Recycling rubber wastes. (Latest citations from the Rubber and Plastics Research Association database). Published Search
The bibliography contains citations concerning research and innovations in the recycling of rubber wastes. Recycling methods and equipment, applications of recycled rubber, and energy recovery systems and performance are among the topics discussed. Recycling methods compared and contrasted with various rubber waste disposal techniques are also included. (Contains a minimum of 96 citations and includes a subject term index and title list.)
Recycling rubber wastes. (Latest citations from the rubber and plastics research association database). Published Search
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The bibliography contains citations concerning research and innovations in the recycling of rubber wastes. Recycling methods and equipment, applications of recycled rubber, and energy recovery systems and performance are among the topics discussed. Recycling methods compared and contrasted with various rubber waste disposal techniques are also included. (Contains a minimum of 89 citations and includes a subject term index and title list.)
Establishment of Monitoring Methods for Autophagy in Rice Reveals Autophagic Recycling of Chloroplasts and Root Plastids during Energy Limitation1[OPEN
Hidema, Jun; Wada, Shinya; Kondo, Eri; Kurusu, Takamitsu; Kuchitsu, Kazuyuki; Makino, Amane; Ishida, Hiroyuki
Autophagy is an intracellular process leading to vacuolar or lysosomal degradation of cytoplasmic components in eukaryotes. Establishment of proper methods to monitor autophagy was a key step in uncovering its role in organisms, such as yeast (Saccharomyces cerevisiae), mammals, and Arabidopsis (Arabidopsis thaliana), in which chloroplastic proteins were found to be recycled by autophagy. Chloroplast recycling has been predicted to function in nutrient remobilization for growing organs or grain filling in cereal crops. Here, to develop our understanding of autophagy in cereals, we established monitoring methods for chloroplast autophagy in rice (Oryza sativa). We generated transgenic rice-expressing fluorescent protein (FP) OsAuTophaGy8 (OsATG8) fusions as autophagy markers. FP-ATG8 signals were delivered into the vacuolar lumen in living cells of roots and leaves mainly as vesicles corresponding to autophagic bodies. This phenomenon was not observed upon the addition of wortmannin, an inhibitor of autophagy, or in an ATG7 knockout mutant. Markers for the chloroplast stroma, stromal FP, and FP-labeled Rubisco were delivered by a type of autophagic body called the Rubisco-containing body (RCB) in the same manner. RCB production in excised leaves was suppressed by supply of external sucrose or light. The release of free FP caused by autophagy-dependent breakdown of FP-labeled Rubisco was induced during accelerated senescence in individually darkened leaves. In roots, nongreen plastids underwent both RCB-mediated and entire organelle types of autophagy. Therefore, our newly developed methods to monitor autophagy directly showed autophagic degradation of leaf chloroplasts and root plastids in rice plants and its induction during energy limitation. PMID:25717038
Energy change of a heavy quark in a viscous quark-gluon plasma with fluctuations
NASA Astrophysics Data System (ADS)
Jiang, Bing-feng; Hou, De-fu; Li, Jia-rong
When a heavy quark travels through the quark-gluon plasma, the polarization and fluctuating chromoelectric fields will be produced simultaneously in the plasma. The drag force due to those fields exerting in return on the moving heavy quark will cause energy change to it. Based on the dielectric functions derived from the viscous chromohydrodynamics, we have studied the collisional energy change of a heavy quark traversing the viscous quark-gluon plasma including fluctuations of chromoelectric field. Numerical results indicate that the chromoelectric field fluctuations lead to an energy gain of the moving heavy quark. Shear viscosity suppresses the fluctuation-induced energy gain and the viscous suppression effect for the charm quark is much more remarkable than that for the bottom quark. While, the fluctuation energy gain is much smaller than the polarization energy loss in magnitude and the net energy change for the heavy quark is at loss.
A non-contact energy transferring system for an electric vehicle-charging system based on recycled products
NASA Astrophysics Data System (ADS)
Matsuda, Y.; Sakamoto, H.; Shibuya, H.; Murata, S.
A non-contact automatic charging system for electric vehicle application is presented. The principle is the same as that of the transformer where the primary and the secondary circuits are separable but coupled with each other without using the hand coupler. In this paper, we present a possibility of removing the core of the secondary coil on the body for reducing the weight of the car. In our experiments, the primary core, which is placed on the earth floor, is made of Mn-Zn ferrite with square shape as 1 m×1 m×10 mm for a large cross-sectional area. The steel floor of the car assists to pass the magnetic flux. An efficiency rate over 90% with the test device of 2 kW is obtained without the conventional secondary core. The leakage inductance is well compensated by a resonance capacitor inserted in the secondary coil. In this experiment, the distance between the primary and the secondary coil is 100 mm and the switching frequency is 100 kHz. In addition, we developed a pavement method for the system. The method utilizes plates made from the waste of expanded polystyrene and rubber mats made from used tire. The plates are set up on the rubber mats and these mats are arranged over the non-contact charging system. The pavements can be replaced easily when the system is exchanged. Therefore, this pavement method is not only practical for the non-contact charging system but is also useful for recycling of resources and reduction of waste matters.
Combustion Byproducts Recycling Consortium
Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower
Ashlines: To promote and support the commercially viable and environmentally sound recycling of coal combustion byproducts for productive uses through scientific research, development, and field testing.
Energy shifts of K- and L-lines as spectroscopic diagnostic of Z-pinch plasmas
Słabkowska, K.; Szymańska, E.; Polasik, M.; Rzadkiewicz, J.; Syrocki, Ł.; Pereira, N. R.
Ultrafast molybdenum wire implosions on the Z machine at Sandia produce intense pulses of multi-keV x-rays from partially ionized plasmas. The most intense radiation comes from a hot, dense core of thermal plasma in ionization equilibrium with Mo ionized to within the L-shell. Non-thermal, energetic electrons in the plasma generate Kα and Kβ radiation, whose energy is affected by Mo's ionization state, and therefore on the plasma temperature. Based on an extensive series of recent computations on this effect, we recalculate the pinch' Mo x-ray spectrum, with reasonable results.
Plasma (Accretion) Disks with High Magnetic Energy Densities
NASA Astrophysics Data System (ADS)
Rousseau, F.; Coppi, B.
``Corrugated'' plasma disks can form in the dominant gravity of a central object when the peak plasma pressure in the disk is of the same order as that of the pressure of the ``external'' magnetic field, while the magnetic field resulting from internal plasma currents is of the same order as the external field. The corrugation refers to a periodic variation of the plasma density in a region around the equatorial plane. The considered structure represents a transition between a ``classical'' accretion disk and a ``rings sequence'' configuration^2. The common feature of the ``corrugated'' and the ``rings sequence'' configurations is the ``crystal'' structure of the magnetic surfaces that consist of a sequence of pairs of oppositely directed toroidal current density filaments. The connection between the characteristics of these configurations and those of the marginally stable ballooning modes that can be found in a model accretion disk is pointed out and analyzed.
PC-5 Waves and Low Energy Plasma in the Outer Magnetosphere
NASA Technical Reports Server (NTRS)
Gallanger, Dennis L.; Vaisberg, Oleg L.; Coffey, Victoria N.
The Interball Tail Probe crosses the dayside magnetopause at low latitudes where it frequently measures low energy ion plasma (<100 eV) in the outer magnetosphere. We present the wave characteristics associated with this cold component.
Experimental observation of the ion energy spectra of Al, Co, and Cu laser produced plasmas
NASA Astrophysics Data System (ADS)
Imanol Apiñaniz, Jon; Peralta Conde, Alvaro; Martínez Perez de Mendiola, Roberto
It is well known that nanosecond laser produced plasmas (LPPs) produce high kinetic energy ions when they expand to vacuum. The acceleration process is nowadays accepted to be due to the formation of a sharp double layer (DL) in the plasma-vacuum boundary. With the purpose of studying this acceleration process, kinetic energy spectra of the plasma ions are measured for each charge state separately. Experimental results are obtained by irradiating planar targets of Cu, Co and Al at a laser wavelength of 532 nm and fluences up to 58.1 J cm-2. The obtained results show two new insights in the ion energy spectra. Firstly, they are non-maxwellian despite the widely accepted local thermal equilibrium in these type of plasmas. Secondly they show non-expected bicomponents distributions. The average energy of each species does not vary linearly with the charge state, suggesting complex acceleration processes.
Energy distributions and radiation transport in uranium plasmas
NASA Technical Reports Server (NTRS)
Miley, G. H.; Bathke, C.; Maceda, E.; Choi, C.
An approximate analytic model, based on continuous electron slowing, has been used for survey calculations. Where more accuracy is required, a Monte Carlo technique is used which combines an analytic representation of Coulombic collisions with a random walk treatment of inelastic collisions. The calculated electron distributions have been incorporated into another code that evaluates both the excited atomic state densities within the plasma and the radiative flux emitted from the plasma.
Modeling of High Kinetic Energy Plasma Jets for Fusion Applications
NASA Astrophysics Data System (ADS)
Bogatu, I. N.; Galkin, S. A.; Kim, J. S.
We used semi-analytical models for high velocity (>200 km/s) and density (>10^17 cm-3) plasma jets to describe the acceleration in coaxial electrodes geometry, the collision, and plasma liner implosion, assuming that jets have merged into a spherical or cylindrical shell. The results are compared with experimental data and are being used for guiding LSP and MACH2 codes simulation and for optimization. The simplest model which uses the adiabatic invariant for oscillator revealed the basic relation between the velocity and the parameters of the plasma accelerator. Plasma slug model was extended for including friction and mass addition by electrode erosion. A simple model of blow-by instability by using the canting angle of the plasma current was formulated. As plasma jets collision at high interfacial Mach number generates shock fronts, we analyzed their possible consequences on the merging process and liner formation. The structure of the spherical shell liner during adiabatic implosion and the effect of the shock wave generated at void closure on the confinement time were also investigated.
Modelling erosion damage from low-energy plasma gun simulations of disruptions
Ehst, D.A.; Hassanein, A.
Energy transfer to material surfaces is dominated by photon radiation through low temperature plasma vapors if tokamak disruptions are due to low kinetic energy particles ({approx_lt} 100 eV). Simple models of radiation transport are derived and incorporated into a fast-running computer routine to model this process. The results of simulations are in good agreement with plasma gun erosion tests on several metal targets.
Energy Distribution of Electrons in Radiation Induced-Helium Plasmas. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Lo, R. H.
Energy distribution of high energy electrons as they slow down and thermalize in a gaseous medium is studied. The energy distribution in the entire energy range from source energies down is studied analytically. A helium medium in which primary electrons are created by the passage of heavy-charged particles from nuclear reactions is emphasized. A radiation-induced plasma is of interest in a variety of applications, such as radiation pumped lasers and gaseous core nuclear reactors.
Antiproton Cooling in the Fermilab Recycler Ring
Nagaitsev, S.; Broemmelsiek, D.; Burov, A.; Carlson, K.; Gattuso, C.; Hu, M.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G.; Schmidt, C. W.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Bolshakov, A.; Zenkevich, P.; Kazakevich, G.
The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.
Antiproton cooling in the Fermilab Recycler Ring
Nagaitsev, S.; Bolshakov, A.; Broemmelsiek, D.; Burov, Alexey V.; Carlson, K.; Gattuso, C.; Hu, M.; Kazakevich, G.; Kramper, B.; Kroc, T.; Leibfritz, J.; Prost, L.; Pruss, S.; Saewert, G; Schmidt, C.W.; Seletskiy, S.; Shemyakin, A.; Sutherland, M.; Tupikov, V.; Warner, A.; Zenkevich, P.; /Fermilab /Moscow, ITEP /Novosibirsk, IYF /Rochester U.
The 8.9-GeV/c Recycler antiproton storage ring is equipped with both stochastic and electron cooling systems. These cooling systems are designed to assist accumulation of antiprotons for the Tevatron collider operations. In this paper we report on an experimental demonstration of electron cooling of high-energy antiprotons. At the time of writing this report, the Recycler electron cooling system is routinely used in collider operations. It has helped to set recent peak luminosity records.
Role of charge transfer in heavy-ion-beam-plasma interactions at intermediate energies
NASA Astrophysics Data System (ADS)
Ortner, A.; Frank, A.; Blažević, A.; Roth, M.
In this paper we investigate the influence of the plasma properties on the charge state distribution of a swift heavy ion beam interacting with a plasma. The main finding is that the charge state in plasma can be lower than in cold matter. The charge state distribution is determined by the ionization and recombination rates which are balancing each other out. Both, ionization and recombination rates, as well as atomic excitation and decay rates, depend on the plasma parameters in different ways. These effects have been theoretically studied by Monte Carlo simulations on the example of an argon ion beam at an energy of 4 MeV /u in a carbon plasma. This study covers a plasma parameter space ranging from ion densities from 1018 to 1023 cm-3 and electron temperatures from 10 to 200 eV.
Relationship between directions of wave and energy propagation for cold plasma waves
NASA Technical Reports Server (NTRS)
Musielak, Zdzislaw E.
The dispersion relation for plasma waves is considered in the 'cold' plasma approximation. General formulas for the dependence of the phase and group velocities on the direction of wave propagation with respect to the local magnetic field are obtained for a cold magnetized plasma. The principal cold plasma resonances and cut-off frequencies are defined for an arbitrary angle and are used to establish basic regimes of frequency where the cold plasma waves can propagate or can be evanescent. The relationship between direction of wave and energy propagation, for cold plasma waves in hydrogen atmosphere, is presented in the form of angle diagrams (angle between group velocity and magnetic field versus angle between phase velocity and magnetic field) and polar diagrams (also referred to as 'Friedrich's diagrams') for different directions of wave propagation. Morphological features of the diagrams as well as some critical angles of propagation are discussed.
Survey of low energy plasma electrons in Saturn's magnetosphere: Voyagers 1 and 2
NASA Technical Reports Server (NTRS)
Sittler, E. C., Jr.; Ogilvie, K. W.; Scudder, J. D.
The low energy plasma electron environment within Saturn's magnetosphere was surveyed by the Plasma Science Experiment (PLS) during the Voyager encounters with Saturn. Over the full energy range of the PLS instrument (10 eV to 6 keV) the electron distribution functions are clearly non-Maxwellian in character; they are composed of a cold (thermal) component with Maxwellian shape and a hot (suprathermal) non-Maxwellian component. A large scale positive radial gradient in electron temperature is observed, increasing from less than 1 eV in the inner magnetosphere to as high as 800 eV in the outer magnetosphere. Three fundamentally different plasma regimes were identified from the measurements: (1) the hot outer magnetosphere, (2) the extended plasma sheet, and (3) the inner plasma torus.
Casimir free energy of metallic films: Discriminating between Drude and plasma model approaches
NASA Astrophysics Data System (ADS)
Klimchitskaya, G. L.; Mostepanenko, V. M.
We investigate the Casimir free energy of a metallic film either sandwiched between two dielectric plates or in vacuum. It is shown that even for a thin film of several tens of nanometer thickness the Casimir free energy and pressure calculated with the Lifshitz theory using the Drude model and the plasma model approaches take significantly different values and can be easily discriminated. According to our results, the classical limit is already achieved for films of about 100-nm thickness if the Drude model approach is used in calculations. In this case the classical expressions for the Casimir free energy and pressure are common for both configurations considered. If the plasma model approach is used, the classical limit is not achieved for any film thickness. Instead, the Casimir free energy and pressure are decreasing exponentially to zero. When the plasma frequency goes to infinity, the Casimir free energy obtained using the Drude model approach goes to a nonzero limit in contradiction with expectations. If the plasma model approach is used the free energy of metallic film goes to zero in the limit of infinitely large plasma frequency. All analytic results are accompanied by numerical computations performed for an Au film and sapphire plates. The possibilities to observe the predicted effects discriminating between the Drude and plasma model approaches are discussed.
Monoenergetic energy doubling in a hybrid laser-plasma wakefield accelerator.
Hidding, B; Königstein, T; Osterholz, J; Karsch, S; Willi, O; Pretzler, G
An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields E(r)∼100 GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems. PMID:20866970
Monoenergetic Energy Doubling in a Hybrid Laser-Plasma Wakefield Accelerator
Hidding, B.; Koenigstein, T.; Osterholz, J.; Willi, O.; Pretzler, G.; Karsch, S.
An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields E{sub r{approx}}100 GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems.
High-resolution submicron retarding field energy analyzer for low-temperature plasma analysis
Blain, M. G.; Stevens, J. E.; Woodworth, J. R.
A retarding potential energy analyzer having 750 nm diameter, self-aligned grid apertures and micron scale grid separation has been fabricated using polycrystalline silicon and silicon dioxide. High-resolution in situ measurements of ion velocity distributions have been demonstrated in inductively coupled argon plasmas. Measurement results agree well with those from a macroscopic analyzer. Important differences are observed in the energies of plasma ions when measured with respect to chamber wall versus those measured with respect to the plasma floating potential. Preliminary measurements under rf bias conditions have also been made and results follow the expected trends. (c) 1999 American Institute of Physics.
Monoenergetic Energy Doubling in a Hybrid Laser-Plasma Wakefield Accelerator
NASA Astrophysics Data System (ADS)
Hidding, B.; Königstein, T.; Osterholz, J.; Karsch, S.; Willi, O.; Pretzler, G.
An ultracompact laser-plasma-generated, fs-scale electron double bunch system can be injected into a high-density driver/witness-type plasma wakefield accelerator afterburner stage to boost the witness electrons monoenergetically to energies far beyond twice their initial energy on the GeV scale. The combination of conservation of monoenergetic phase-space structure and fs duration with radial electric plasma fields Er˜100GV/m leads to dramatic transversal witness compression and unprecedented charge densities. It seems feasible to upscale and implement the scheme to future accelerator systems.
Energy deposition of heavy ions in the regime of strong beam-plasma correlations.
Gericke, D O; Schlanges, M
The energy loss of highly charged ions in dense plasmas is investigated. The applied model includes strong beam-plasma correlation via a quantum T-matrix treatment of the cross sections. Dynamic screening effects are modeled by using a Debye-like potential with a velocity dependent screening length that guarantees the known low and high beam velocity limits. It is shown that this phenomenological model is in good agreement with simulation data up to very high beam-plasma coupling. An analysis of the stopping process shows considerably longer ranges and a less localized energy deposition if strong coupling is treated properly. PMID:12689203
Exploring turbulent energy dissipation and particle energization in space plasmas: the science of THOR mission
NASA Astrophysics Data System (ADS)
Retinò, Alessandro
The Universe is permeated by hot, turbulent magnetized plasmas. They are found in active galactic nuclei, supernova remnants, the intergalactic and interstellar medium, as well as in the solar corona, the solar wind and the Earth's magnetosphere. Turbulent plasmas are also found in laboratory devices such as e.g. tokamaks. Our comprehension of the plasma Universe is largely based on measurements of electromagnetic radiation such as light or X-rays which originate from particles that are heated and accelerated as a result of energy dissipation in turbulent environments. Therefore it is of key importance to study and understand how plasma is energized by turbulence. Most of the energy dissipation occurs at kinetic scales, where plasma no longer behaves as a fluid and the properties of individual plasma species (electrons, protons and other ions) become important. THOR (Turbulent Heating ObserveR - http://thor.irfu.se/) is a space mission currently in Study Phase as candidate for M-class mission within the Cosmic Vision program of the European Space Agency. The scientific theme of the THOR mission is turbulent energy dissipation and particle energization in space plasmas, which ties in with ESA's Cosmic Vision science. The main focus is on turbulence and shock processes, however areas where the different fundamental processes interact, such as reconnection in turbulence or shock generated turbulence, are also of high importance. The THOR mission aims to address fundamental questions such as how plasma is heated and particles are accelerated by turbulent fluctuations at kinetic scales, how energy is partitioned among different plasma components and how dissipation operates in different regimes of turbulence. To reach the goal, a careful design of the THOR spacecraft and its payload is ongoing, together with a strong interaction with numerical simulations. Here we present the science of THOR mission and we discuss implications of THOR observations for space
The feasibility of recycling certain categories of water used in the manufacture of airplanes was demonstrated. Water in four categories was continuously recycled in 380-liter (100-gallon) treatment plants; chemical process rinse water, dye-penetrant crack-detection rinse water, ...
ERIC Educational Resources Information Center
Wisconsin State Dept. of Natural Resources, Madison.
Hands-on activities in this guide are designed to help preschool children (ages 3-5) understand that reducing, reusing, and recycling preserves natural resources and prolongs the life of landfills. Children sort, match and compare recyclable items and learn to separate some items by number and color. The 29 activities are divided into units that…
Martin Hu
The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.
The recycling of carbon dioxide to methanol and dimethyl ether is seen to offer a substantial route to renewable and environmentally carbon neutral fuels. One of the authors has championed the "Methanol Economy" in articles and a book. By recycling ambient CO2, the authors argue ...
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This article describes the increasing use of aluminum in automobiles and the need to recycle to benefit further growth of aluminum applications by assuring an economical, high-quality source of metal. The article emphasizes that coordination of material specifications among designers can raise aluminum scrap value and facilitate recycling. Applications of aluminum in automobile construction are discussed.
ERIC Educational Resources Information Center
Briscoe, Georgia
Discussion of recycling paper in law libraries is also applicable to other types of libraries. Results of surveys of law libraries that investigated recycling practices in 1987 and again in 1990 are reported, and suggestions for reducing the amount of paper used and reusing as much as possible are offered. (LRW)
ERIC Educational Resources Information Center
Cummins, William M.
Outlines a Michigan summer camp's efforts to reduce solid waste disposal by recycling cardboard, tin, glass, aluminum, and plastic milk containers. Points out variables affecting the success of such efforts. Discusses Michigan state funding for the development of recycling programs. (SV)
Electron-ion energy partition when a charged particle slows in a plasma: results.
Brown, Lowell S; Preston, Dean L; Singleton, Robert L
This paper concerns plasmas in which the electrons and ions may have different temperatures. This is a case that must be examined because nuclear fusion processes, such as those that appear in ICF capsules, have ions whose temperature runs away from the electron temperature. A fast charged particle traversing a plasma--such as the α particle created in deuterium-tritium fusion--loses its energy to both the electrons and the ions in the plasma. In this paper, we present and discuss the results for the energy partition, the fractions E(e)/E(0) and E(I)/E(0) of the initial energy E(0) of this projectile particle that are deposited into the electrons and ions when it has slowed to its minimum energy distribution. The calculations, performed in the following paper [Brown, Preston, and Singleton Jr., Phys. Rev. E 86, 016407 (2012)], use a well-defined Fokker-Planck equation for the phase-space distribution of the charged projectiles in a weakly to moderately coupled plasma. The Fokker-Planck equation holds to first subleading order in the dimensionless plasma coupling constant, which translates to computing to order n ln n (leading) and n (subleading) in the plasma density n. We present an examination of the energy partition for the general case, in which the temperatures of the ions and electrons in the background plasma are not equal. The energy partitions for a background plasma in thermal equilibrium have been previously computed, but the order n terms have not been calculated, only estimated. Our Fokker-Planck formulation provides an unambiguous, precise definition of the energy fractions. PMID:23005549
Operational experience and performance characteristics of a valve-regulated lead-acid battery energy-storage system for providing the customer with critical load protection and energy-management benefits at a lead-recycling plant
NASA Astrophysics Data System (ADS)
Hunt, G. W.
The Power Control Division of GNB Technologies, commissioned on May 13, 1996 a new facility which houses a 5-MW battery energy-storage system (BESS) at GNB's Lead Recycling Centre in Vernon, CA. When the plant loses utility power (which typically happens two or three times a year), the BESS will provide up to 5 MW of power at 4160 VAC in support of all the plant loads. Since the critical loads are not isolated, it is necessary to carry the entire plant load (maximum of 5 MVA) for a short period immediately following an incident until non-critical loads have been automatically shed. Plant loading typically peaks at 3.5 MVA with critical loads of about 2.1 MVA. The BESS also provides the manufacturing plant with customer-side-of-the-meter energy management options to reduce its energy demand during peak periods of the day. The BESS has provided a reduction in monthly electric bills through daily peak-shaving. By design, the battery can provide up to 2.5 MWh of energy and still retain 2.5 MWh of capacity in reserve to handle the possibility of a power outage in protecting the critical loads for up to 1 h. By storing energy from the utility during off-peak hours of the night in the batteries when the cost is low (US4.5¢ per kWh), GNB can then discharge this energy during high demand periods of the day (US14.50 per kW). For example, by reducing its peak demand by 300 kW, the lead-recycling centre can save over US4000 per month in its electric bills. The BESS at Vernon represents a first large-scale use of valve-regulated lead-acid batteries in such a demanding application. This paper presents a summary of the operational experience and performance characteristics of the BESS over the past 2 years.
Plasma simulations of emission line regions in high energy environments
NASA Astrophysics Data System (ADS)
Richardson, Chris T.
This dissertation focuses on understanding two different, but in each case extreme, astrophysical environments: the Crab Nebula and emission line galaxies. These relatively local objects are well constrained by observations and are test cases of phenomena seen at high-z where detailed observations are rare. The tool used to study these objects is the plasma simulation code known as Cloudy. The introduction provides a brief summary of relevant physical concepts in nebular astrophysics and presents the basic features and assumptions of Cloudy. The first object investigated with Cloudy, the Crab Nebula, is a nearby supernova remnant that previously has been subject to photoionization modeling to reproduce the ionized emission seen in the nebula's filamentary structure. However, there are still several unanswered questions: (1) What excites the H2 emitting gas? (2) How much mass is in the molecular component? (3) How did the H2 form? (4) What is nature of the dust grains? A large suite of observations including long slit optical and NIR spectra over ionized, neutral and molecular gas in addition to HST and NIR ground based images constrain a particularly bright region of H2 emission, Knot 51, which exhibits a high excitation temperature of ˜3000 K. Simulations of K51 revealed that only a trace amount of H2 is needed to reproduce the observed emission and that H2 forms through an uncommon nebular process known as associative detachment. The final chapters of this dissertation focus on interpreting the narrow line region (NLR) in low-z emission line galaxies selected by a novel technique known as mean field independent component analysis (MFICA). A mixture of starlight and radiation from an AGN excites the gas present in galaxies. MFICA separates galaxies over a wide range of ionization into subsets of pure AGN and pure star forming galaxies allowing simulations to reveal the properties responsible for their observed variation in ionization. Emission line ratios can
MHD model of conversion of the plasma energy of a thermonuclear microexplosion
NASA Astrophysics Data System (ADS)
Bychkova, L. P.; Kalinin, A. V.; Rutkevich, I. M.
A preliminary analysis is presented of the direct conversion of the energy of a thermonuclear microexplosion into electrical energy in a reactor which is combined with a pulsed induction-type MHD generator connected to a resistive load. The following factors are taken into account: (1) the relation between the average parameters of the plasma and the magnetic field, (2) the finite dimensions of the region of magnetic energy localization, and (3) the effect of the high initial energy density of the plasma. It is found that the choice of the size of the load significantly determines the maximum efficiency of the generator.
Estimation of the energy transferred from the capacitor bank to the plasma in plasma focus systems
Cardenas, Miguel; Soto, Leopoldo
We consider the snowplow model to describe the axial phase of a plasma focus device. We show that, within this framework, the dynamics of a given system can be recovered at different energetic and geometric scales. Then, we consider two different criteria that would plausibly optimize the plasma focus performance. By solving the dynamics equations for the axial phase, we estimate the values of the parameters that do indeed satisfy the aforementioned criteria and compare those values with the corresponding ones attached to few practical devices.
Experimental measurement of plasma parameters and electron energy distribution in ferrite-core side type Ar/He inductively coupled plasma
NASA Astrophysics Data System (ADS)
Han, Duksun; Bang, Jin-Young; Lee, Hyo-Chang; Chung, Chin-Wook
Spatial distributions of a plasma density and an effective electron temperature (Teff) were studied from the measurement of an electron energy probability function (EEPF) in the side type ferrite-core inductively coupled plasma with an argon-helium mixture. As the helium gas was diluted at the fixed total gas pressure of 5 mTorr in an argon discharge, the distribution of the plasma density was changed from a concave to a flat, and finally became a convex, while all spatial profiles of Teff were the hollow shapes with the helium dilution. This evolution of the plasma uniformity with the helium gas could be explained by the increased energy relaxation length and the changed plasma potential, indicating the transition of the electron kinetics from the local to non-local kinetics. From this result, it is expected that the addition of helium gas could be applied as a method to control the plasma uniformity in a large area plasma processing.
Recycling behaviour in healthcare: waste handling at work.
Vogt, Joachim; Nunes, Katia R A
This article reviews the motivational factors for environmental behaviour in general, presenting a case study on recycling disposable plastics in hospitals. Results show that 90% of over 600 employees from six analysed hospitals in Germany reported that the recycling of disposable plastics on the wards makes sense from an environmental and economic point of view. The case study reports an assessment of recycling attitudes and problems of hospital staff, mainly nurses. Employees in eco-certified hospitals were much more satisfied and reported fewer problems with the recycling system. The gender effect was significant only for saving energy, while age correlated with nearly all reported pro-environmental behaviour at home. At work, the mere introduction of a recycling system was insufficient to achieve good recycling results. Based on the study findings, recommendations are given aimed at improving the safety and sustainability of the recycling system. PMID:24617848
Study of radiatively sustained cesium plasmas for solar energy conversion
NASA Technical Reports Server (NTRS)
Palmer, A. J.; Dunning, G. J.
The results of a study aimed at developing a high temperature solar electric converter are reported. The converter concept is based on the use of an alkali plasma to serve as both an efficient high temperature collector of solar radiation as well as the working fluid for a high temperature working cycle. The working cycle is a simple magnetohydrodynamic (MHD) Rankine cycle employing a solid electrode Faraday MHD channel. Research milestones include the construction of a theoretical model for coupling sunlight in a cesium plasma and the experimental demonstration of cesium plasma heating with a solar simulator in excellent agreement with the theory. Analysis of a solar MHD working cycle in which excimer laser power rather than electric power is extracted is also presented. The analysis predicts a positive gain coefficient on the cesium-xenon excimer laser transition.
Plasma Physics/Fusion Energy Education at the Liberty Science Center
NASA Astrophysics Data System (ADS)
Zwicker, Andrew; Delooper, John; Carpe, Andy; Amara, Joe; Butnick, Nancy; Lynch, Ellen; Osowski, Jeff
The Liberty Science Center (LSC) is the largest (300,000 sq. ft.) education resource in the New Jersey-New York City region. A major 109 million expansion and renewal was recently completed. Accordingly, PPPL has expanded the science education collaboration with the Center into three innovative, hands-on programs. On the main floor, a new fusion exhibit is one of the focuses of ``Energy Quest.'' This includes a DC glow discharge tube with a permanent external magnet allowing visitors to manipulate the plasma while reading information on plasma creation and fusion energy. In the section of LSC dedicated to intensive science investigations (20,000 sq. ft) we have added ``Live from NSTX'' which will give students an opportunity to connect via video-conferencing to the NSTX control room during plasma operations. A prototype program was completed in May, 2007 with three high school physics classes and will be expanded when NSTX resumes operation. Finally, a plasma physics laboratory in this area will have a fully functioning, research-grade plasma source that will allow long-term visitors an opportunity to perform experiments in plasma processing, plasma spectroscopy, and dusty plasmas.
Two water-specific aquaporins at the apical and basal plasma membranes of insect epithelia: molecular basis for water recycling through the cryptonephric rectal complex of lepidopteran larvae.
Azuma, Masaaki; Nagae, Tomone; Maruyama, Mariya; Kataoka, Naoya; Miyake, Seiji
Larval lepidopteran and coleopteran insects have evolved a specialised cryptonephric system in the hindgut in which water is constantly and rapidly taken up before defecation. In the silkworm, Bombyx mori, the movement of water through the epithelia within the cryptonephric rectal complex is likely facilitated by the two aquaporins, AQP-Bom1 and AQP-Bom3. Both are functionally water-specific and are predominantly expressed in the hindgut (colon and rectum). Phylogenetically, AQP-Bom1 and AQP-Bom3 belong to the DRIP (Drosophila integral protein) and PRIP (Pyrocoelia rufa integral protein) subfamilies, respectively, of the insect AQP clade. In immunoblot analyses using antipeptide antibodies for each Bombyx AQP, the predicted molecular mass for the respective AQPs were around 25 kDa, and further indicated that both tended to be oligomerised as a homotetramer (∼110 kDa). AQP-Bom1 [DRIP] was exclusively expressed at the apical plasma membrane of colonic and rectal epithelial cells, whereas AQP-Bom3 [PRIP] was expressed at the basal plasma membrane of these cells. This polarised localisation of DRIP/PRIP was also observed in the outer cryptonephric Malpighian tubules (outer cMT) and in the six tubules just outside the cryptonephric rectal complex (rectal lead MT). In the rectal epithelia, water is transported from the rectal lumen to the perinephric space and then deposited into the lumen of the outer cMT; the water then goes through the tubular lumen to exit the complex and is finally transported across the rectal lead MT. We conclude that rectal water retrieval into the haemocoele occurs at the very limited region of the water-permeable sites in MT epithelia after passing the rectal and cMT epithelia and that the high osmotic permeability is due to the presence of two distinct water-specific AQPs (DRIP and PRIP) in the epithelial cells of lepidopteran hindgut. PMID:22285686
Improvement of early cell adhesion on Thai silk fibroin surface by low energy plasma.
Amornsudthiwat, Phakdee; Mongkolnavin, Rattachat; Kanokpanont, Sorada; Panpranot, Joongjai; Wong, Chiow San; Damrongsakkul, Siriporn
Low energy plasma has been introduced to treat the surface of Thai silk fibroin which should be enhanced for cell adhesion due to its native hydrophobic surface. Plasma surface treatment could introduce desirable hydrophilic functionalities on the surface without using any chemicals. In this work, nitrogen glow discharge plasma was generated by a low energy AC50Hz power supply system. The plasma operating conditions were optimized to reach the highest nitrogen active species by using optical emission spectroscopy. X-ray photoelectron spectroscopy (XPS) revealed that amine, hydroxyl, ether, and carboxyl groups were induced on Thai silk fibroin surface after plasma treatment. The results on Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy confirmed that the plasma treated effects were only on the outermost layer since there was no change in the bulk chemistry. The surface topography was insignificantly changed from the detection with atomic force microscopy (AFM). The plasma-treated effects were the improved surface wettability and cell adhesion. After a 90-s treatment, the water contact angle was at 20°, while the untreated surface was at 70°. The early cell adhesion of L929 mouse fibroblast was accelerated. L929 cells only took 3h to reach 100% cell adhesion on 90 s N2 plasma-treated surface, while there was less than 50% cell adhesion on the untreated Thai silk fibroin surface after 6h of culture. The cell adhesion results were in agreement with the cytoskeleton development. L929 F-actin was more evident on 90 s N2 plasma-treated surface than others. It could be concluded that a lower energy AC50Hz plasma system enhanced early L929 mouse fibroblast adhesion on Thai silk fibroin surface without any significant change in surface topography and bulk chemistry. PMID:23893032
Evaluation of radioactive scrap metal recycling
Nieves, L.A.; Chen, S.Y.; Kohout, E.J.; Nabelssi, B.; Tilbrook, R.W.; Wilson, S.E.
This report evaluates the human health risks and environmental and socio-political impacts of options for recycling radioactive scrap metal (RSM) or disposing of and replacing it. Argonne National Laboratory (ANL) is assisting the US Department of Energy (DOE), Office of Environmental Restoration and Waste Management, Oak Ridge Programs Division, in assessing the implications of RSM management alternatives. This study is intended to support the DOE contribution to a study of metal recycling being conducted by the Task Group on Recycling and Reuse of the Organization for Economic Cooperation and Development. The focus is on evaluating the justification for the practice of recycling RSM, and the case of iron and steel scrap is used as an example in assessing the impacts. To conduct the evaluation, a considerable set of data was compiled and developed. Much of this information is included in this document to provide a source book of information.
Chorus intensity modulation driven by time-varying field-aligned low-energy plasma
NASA Astrophysics Data System (ADS)
Nishimura, Y.; Bortnik, J.; Li, W.; Liang, J.; Thorne, R. M.; Angelopoulos, V.; Le Contel, O.; Auster, U.; Bonnell, J. W.
Recent studies have shown that chorus waves are responsible for scattering and precipitating the energetic electrons that drive the pulsating aurora. While some of the chorus intensity modulation events are correlated with <~100 eV electron density modulation, most of the chorus intensity modulation events in the postmidnight sector occur without apparent density changes. Although it is generally difficult to measure evolution of low-energy (<~20 eV) electron fluxes due to constraints imposed by the spacecraft potential and electrostatic analyzer (ESA) energy range limit, we identified using Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite data that low-energy ions of ~100 eV show density modulation that is correlated with chorus intensity modulation. Those low-energy ions and electrons are field-aligned with major peaks in 0° (for northern hemisphere winter event) and 180° (for northern hemisphere summer event) pitch angle, indicating that outflowing plasma from the sunlit hemisphere is the source of the low-energy plasma density modulation near the equator. Plasma sheet plasma density, and ambient electric and magnetic fields do not show modulations that are correlated with the chorus intensity modulation. Assuming charge neutrality, the low-energy ions can be used to represent cold plasma density in wave growth rate calculations, and the enhancements of the low-energy plasma density are found to contribute most effectively to chorus linear growth rates. These results suggest that chorus intensity modulation is driven by a feedback process where outflowing plasma due to energetic electron precipitation increases the equatorial density that drives further electron precipitation.
On the evolution of jet energy and opening angle in strongly coupled plasma
NASA Astrophysics Data System (ADS)
Chesler, Paul M.; Rajagopal, Krishna
We calculate how the energy and the opening angle of jets in {N} = 4 SYM theory evolve as they propagate through the strongly coupled plasma of that theory. We define the rate of energy loss dE jet /dx and the jet opening angle in a straightforward fashion directly in the gauge theory before calculating both holographically, in the dual gravitational description. In this way, we rederive the previously known result for dE jet /dx without the need to introduce a finite slab of plasma. We obtain a striking relationship between the initial opening angle of the jet, which is to say the opening angle that it would have had if it had found itself in vacuum instead of in plasma, and the thermalization distance of the jet. Via this relationship, we show that {N} = 4 SYM jets with any initial energy that have the same initial opening angle and the same trajectory through the plasma experience the same fractional energy loss. We also provide an expansion that describes how the opening angle of the {N} = 4 SYM jets increases slowly as they lose energy, over the fraction of their lifetime when their fractional energy loss is not yet large. We close by looking ahead toward potential qualitative lessons from our results for QCD jets produced in heavy collisions and propagating through quark-gluon plasma.
Current fundamental science challenges in low temperature plasma science that impact energy security and international competitiveness
NASA Astrophysics Data System (ADS)
Hebner, Greg
Products and consumer goods that utilize low temperature plasmas at some point in their creation touch and enrich our lives on almost a continuous basis. Examples are many but include the tremendous advances in microelectronics and the pervasive nature of the internet, advanced material coatings that increase the strength and reliability of products from turbine engines to potato chip bags, and the recent national emphasis on energy efficient lighting and compact fluorescent bulbs. Each of these products owes their contributions to energy security and international competiveness to fundamental research investments. However, it would be a mistake to believe that the great commercial success of these products implies a robust understanding of the complicated interactions inherent in plasma systems. Rather, current development of the next generation of low temperature plasma enabled products and processes is clearly exposing a new set of exciting scientific challenges that require leaps in fundamental understanding and interdisciplinary research teams. Emerging applications such as liquid-plasma systems to improve water quality and remediate hazardous chemicals, plasma-assisted combustion to increase energy efficiency and reduce emissions, and medical applications promise to improve our lives and the environment only if difficult science questions are solved. This talk will take a brief look back at the role of low temperature plasma science in enabling entirely new markets and then survey the next generation of emerging plasma applications. The emphasis will be on describing the key science questions and the opportunities for scientific cross cutting collaborations that underscore the need for increased outreach on the part of the plasma science community to improve visibility at the federal program level. This work is supported by the DOE, Office of Science for Fusion Energy Sciences, and Sandia National Laboratories, a multi-program laboratory managed and operated
Jet energy loss in the quark-gluon plasma by stream instabilities
Mannarelli, Massimo; Manuel, Cristina; Gonzalez-Solis, Sergi; Strickland, Michael
We study the evolution of the plasma instabilities induced by two jets of particles propagating in opposite directions and crossing a thermally equilibrated non-Abelian plasma. In order to simplify the analysis we assume that the two jets of partons can be described with uniform distribution functions in coordinate space and by Gaussian distribution functions in momentum space. We find that while crossing the quark-gluon plasma, the jets of particles excite unstable chromomagnetic and chromoelectric modes. These fields interact with the particles (or hard modes) of the plasma inducing the production of currents; thus, the energy lost by the jets is absorbed by both the gauge fields and the hard modes of the plasma. We compare the outcome of the numerical simulations with the analytical calculation performed assuming that the jets of particles can be described by a tsunamilike distribution function. We find qualitative and semiquantitative agreement between the results obtained with the two methods.
Application of a pulsed, RF-driven, multicusp source for low energy plasma immersion ion implantation
Wengrow, A.B.; Leung, K.N.; Perkins, L.T.; Pickard, D.S.; Rickard, M.; Williams, M.D.; Tucker, M.
The multicusp ion source can produce large volumes of uniform, quiescent, high density plasmas. A plasma chamber suited for plasma immersion ion implantation (PIII) was readily made. Conventional PIII pulses the bias voltage applied to the substrate which is immersed in a CW mode plasma. Here, a method by which the plasma itself is pulsed was developed. Typically pulse lengths of 500 {mu}s are used and are much shorter than that of the substrate voltage pulse (5-15 ms). This approach, together with low gas pressures and low bias voltages, permits the constant energy implantation of an entire wafer simultaneously without glow discharge. Results show that this process can yield implant currents of up to 2.5 mA/cm{sup 2}; thus very short implant times can be achieved. Uniformity of the ion flux is also discussed. As this method can be scaled to any dimension, it can be made to handle any size wafer.
Relativistic corrections for screening effects on the energies of hydrogen-like atoms embedded in plasmas
Poszwa, A.; Bahar, M. K.
The influence of relativistic and plasma screening effects on energies of hydrogen-like atoms embedded in plasmas has been studied. The Dirac equation with a more general exponential cosine screened potential has been solved numerically and perturbatively, by employing the direct perturbation theory. Properties of spectra corresponding to bound states and to different sets of the potential parameters have been studied both in nonrelativistic and relativistic approximations. Binding energies, fine-structure splittings, and relativistic energy shifts have been determined as functions of parameters of the potential. The results have been compared with the ones known from the literature.
Disentangling fluxes of energy and matter in plasma-surface interactions: Effect of process parameters
Wolter, M.; Levchenko, I.; Ostrikov, K.; Kersten, H.; Kumar, S.
The possibility to discriminate between the relative importance of the fluxes of energy and matter in plasma-surface interaction is demonstrated by the energy flux measurements in low-temperature plasmas ignited by the radio frequency discharge (power and pressure ranges 50-250 W and 8-11.5 Pa) in Ar, Ar+H{sub 2}, and Ar+H{sub 2}+CH{sub 4} gas mixtures typically used in nanoscale synthesis and processing of silicon- and carbon-based nanostructures. It is shown that by varying the gas composition and pressure, the discharge power, and the surface bias one can effectively control the surface temperature and the matter supply rates. The experimental findings are explained in terms of the plasma-specific reactions in the plasma bulk and on the surface.
Precise energy eigenvalues of hydrogen-like ion moving in quantum plasmas
Dutta, S.; Saha, Jayanta K.; Mukherjee, T. K.
The analytic form of the electrostatic potential felt by a slowly moving test charge in quantum plasma is developed. It has been shown that the electrostatic potential is composed of two parts: the Debye-Huckel screening term and the near-field wake potential. The latter depends on the velocity of the test charge as well as on the number density of the plasma electrons. Rayleigh-Ritz variational calculation has been done to estimate precise energy eigenvalues of hydrogen-like carbon ion under such plasma environment. A detailed analysis shows that the energy levels gradually move to the continuum with increasing plasma electron density while the level crossing phenomenon has been observed with the variation of ion velocity.
Magnetowave Induced Plasma Wakefield Acceleration for Ultra High Energy Cosmic Rays
Chang, Feng-Yin; Chen, Pisin; Lin, Guey-Lin; Noble, Robert; Sydora, Richard; /Alberta U.
Magnetowave induced plasma wakefield acceleration (MPWA) in a relativistic astrophysical outflow has been proposed as a viable mechanism for the acceleration of cosmic particles to ultrahigh energies. Here we present simulation results that clearly demonstrate the viability of this mechanism for the first time. We invoke the high frequency and high speed whistler mode for the driving pulse. The plasma wakefield obtained in the simulations compares favorably with our newly developed relativistic theory of the MPWA. We show that, under appropriate conditions, the plasma wakefield maintains very high coherence and can sustain high-gradient acceleration over hundreds of plasma skin depths. Invoking active galactic nuclei as the site, we show that MPWA production of ultrahigh energy cosmic rays beyond ZeV (10{sup 21} eV) is possible.
Electron density compression and oscillating effects on laser energy absorption in overdense plasma targets.
Ge, Z Y; Zhuo, H B; Yu, W; Yang, X H; Yu, T P; Li, X H; Zou, D B; Ma, Y Y; Yin, Y; Shao, F Q; Peng, X J
An analytical model for energy absorption during the interaction of an ultrashort, ultraintense laser with an overdense plasma is proposed. Both the compression effect of the electron density profile and the oscillation of the electron plasma surface are self-consistently included, which exhibit significant influences on the laser energy absorption. Based on our model, the general scaling law of the compression effect depending on laser strength and initial density is derived, and the temporal variation of the laser absorption due to the boundary oscillating effect is presented. It is found that due to the oscillation of the electron plasma surface, the laser absorption rate will vibrate periodically at ω or 2ω frequency for the p-polarized and s-polarized laser, respectively. The effect of plasma collision on the laser absorption has also been investigated, which shows a considerable rise in absorption with increasing electron-ion collision frequency for both polarizations. PMID:24730955
A direct measurement of the energy flux density in plasma surface interaction
NASA Astrophysics Data System (ADS)
Dussart, Remi; Thomann, Anne-Lise; Semmar, Nadjib; Pichon, Laurianne; Bedra, Larbi; Mathias, Jacky; Tessier, Yves; Lefaucheux, Philippe
The energy flux transferred from a plasma to a surface is a key issue for materials processing (sputtering, etching). We present direct measurements made with a Heat Flux Microsensor (HFM) in an Ar plasma interacting with the surface of the sensor. The HFM is a thermopile of about one thousand metal couples mounted in parallel. An Inductively Coupled Plasma in Argon was used to make the experiments. Langmuir probe and tuneable laser diode absorption measurements were carried out to estimate the contribution of ions, neutrals (conduction) and metastables. In order to evaluate the ability of the HFM to measure the part due to chemical reactions, a Si surface in contact with the HFM was submitted to an SF6 plasma. The direct measurements are in good agreement with the estimation we made knowing the etch rate and the enthalpy of the reaction. Finally, tests were performed on a sputtering reactor. Additional energy flux provided by condensing atoms (Pt) was also measured.
Energy relaxation of intense laser pulse-produced plasmas
NASA Astrophysics Data System (ADS)
Shihab, M.; Abou-Koura, G. H.; El-Siragy, N. M.
We describe a collisional radiative model (CRE) of homogeneously expanded nickel plasmas in vacuum. The CRE model is coupled with two separate electron and ion temperature magneto-hydrodynamic equations. On the output, the model provides the temporal variation of the electron temperature, ion temperature, and average charge state. We demonstrate the effect of three-body recombination ({∝}N_e T^{-9/2}_e) on plasma parameters, as it changes the time dependence of electron temperature from t^{-2} to t^{-1} and exhibits a pronounced effect leading to a freezing feature in the average charge state. In addition, the effect of the three-body recombination on the warm up of ions and delaying the equilibration is addressed.
Advances in Langmuir probe diagnostics of the plasma potential and electron-energy distribution function in magnetized plasma
NASA Astrophysics Data System (ADS)
Popov, Tsv K.; Dimitrova, M.; Ivanova, P.; Kovačič, J.; Gyergyek, T.; Dejarnac, R.; Stöckel, J.; Pedrosa, M. A.; López-Bruna, D.; Hidalgo, C.
Advanced Langmuir probe techniques for evaluating the plasma potential and electron-energy distribution function (EEDF) in magnetized plasma are reviewed. It is shown that when the magnetic field applied is very weak and the electrons reach the probe without collisions in the probe sheath the second-derivative Druyvesteyn formula can be used for EEDF evaluation. At low values of the magnetic field, an extended second-derivative Druyvesteyn formula yields reliable results, while at higher values of the magnetic field, the first-derivative probe technique is applicable for precise evaluation of the plasma potential and the EEDF. There is an interval of intermediate values of the magnetic field when both techniques—the extended second-derivative and the first-derivative one—can be used. Experimental results from probe measurements in different ranges of magnetic field are reviewed and discussed: low-pressure argon gas discharges in the presence of a magnetic field in the range from 0.01 to 0.08 T, probe measurements in circular hydrogen plasmas for high-temperature fusion (magnetic fields from 0.45 T to 1.3 T) in small ISTTOK and CASTOR tokamaks, D-shape COMPASS tokamak plasmas, as well as in the TJ-II stellarator. In the vicinity of the last closed flux surface (LCFS) in tokamaks and in the TJ-II stellarator, the EEDF obtained is found to be bi-Maxwellian, while close to the tokamak chamber wall it is Maxwellian. The mechanism of the appearance of a bi-Maxwellian EEDF in the vicinity of the LCFS is discussed. Comparison of the results from probe measurements with those obtained from calculations using the ASTRA and EIRENE codes shows that the main reason for the appearance of a bi-Maxwellian EEDF in the vicinity of the LCFS is the ionization of the neutral atoms.
Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator
Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Joshi, Chandrashekhar; Katsouleas, Thomas; Kirby, Neil; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.
The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively doubles their energy, producing the energy gain of the 3-km-long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-energy physics applications.
Effect of Rf Ground Location in an Inductively Coupled Plasma Reactor on the Plasma Density and Ion Energy
NASA Astrophysics Data System (ADS)
Radovanov, Svetlana; Anderson, Harold; Bell, Gary; Zhang, Hong-Mei; Hoffman, Dan; Resta, Victoria; Rasmussen, Dave
Measurements of the electromagnetic (EM) fields, plasma density and ion energy distribution (IED)were performed in a high density ICP etch tool.The obtained EM fields have shown that a virtual radio frequency (RF) ground exists on the current strap. A set of experiments were performed to investigate the impact of altering the location of this RF ground on the EM fields produced and on the uniformity of the plasma density and ion energy distribution. Vacuum RF field measurements for "virtual" and "imposed" ground configurations show a dramatic effect on the electric and magnetic fields. In the standard "virtual" ground case (ground located near the outer edge of the coil), the electric field magnitude is center peaked, while in the "imposed" ground mode (ground shifted toward the coil center), the electric field magnitude has an annular shape. A miniaturized retarding grid ion energy analyzer (mini-IEA) was used to determine radial profiles of the ion saturation current and ion energy distribution (IED)[1]. Radial profiles of the ion current in the "virtual" ground mode are uniform and IEDs are sharp and narrow. In the "imposed" ground mode an annular shaped profile was obtained. The IEDs are significantly broadened, suggesting a larger electrostatic coupling component to the discharge. The changes in the IED are important owing to their impact on the isotropy of etching of microelectronic devices and uniformity of plasma generation. ( G.W. Gibson, Jr, H.H. Sawin, I. Tepermeister, D.E.Ibbotson, and J.T.C. Lee, J. Vac. Sci. Technol. B, 12, 2333 (1994).)
ZaP-HD: High Energy Density Z-Pinch Plasmas using Sheared Flow Stabilization
NASA Astrophysics Data System (ADS)
Golingo, R. P.; Shumlak, U.; Nelson, B. A.; Claveau, E. L.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Ross, M. P.; Weed, J. R.
The ZaP-HD flow Z-pinch project investigates scaling the flow Z-pinch to High Energy Density Plasma, HEDP, conditions by using sheared flow stabilization. ZaP used a single power supply to produce 100 cm long Z-pinches that were quiescent for many radial Alfven times and axial flow-through times. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are dimensionally large and persist for extended durations. The ZaP-HD device replaces the single power supply from ZaP with two separate power supplies to independently control the plasma flow and current in the Z-pinch. Equilibrium is determined by diagnostic measurements of the density with interferometry and digital holography, the plasma flow and temperature with passive spectroscopy, the magnetic field with surface magnetic probes, and plasma emission with optical imaging. The diagnostics fully characterize the plasma from its initiation in the coaxial accelerator, through the pinch, and exhaust from the assembly region. The plasma evolution is modeled with high resolution codes: Mach2, WARPX, and NIMROD. Experimental results and scaling analyses are presented. This work is supported by grants from the U.S. Department of Energy and the U.S. National Nuclear Security Administration.
Strongly Driven Magnetic Reconnection in a Magnetized High-Energy-Density Plasma
NASA Astrophysics Data System (ADS)
Fiksel, G.; Barnak, D. H.; Chang, P.-Y.; Haberberger, D.; Hu, S. X.; Ivancic, S.; Nilson, P. M.; Fox, W.; Deng, W.; Bhattacharjee, A.; Germaschewski, K.
Magnetic reconnection in a magnetized high-energy-density plasma is characterized by measuring the dynamics of the plasma density and magnetic field between two counter-propagating and colliding plasma flows. The density and magnetic field were profiled using the 4 ω angular filter refractometry and fast proton deflectometry diagnostics, respectively. The plasma flows are created by irradiating oppositely placed plastic targets with 1.8-kJ, 2-ns laser beams on the OMEGA EP Laser System. The two plumes are magnetized by an externally controlled magnetic field with an x-type null point geometry with B = 0 at the midplane and B = 8 T at the targets. The interaction region is pre-filled with a low-density background plasma. The counterflowing super-Alfvénic plasma plumes sweep up and compress the magnetic field and the background plasma into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing for the first detailed observation of a stretched current sheet in laser-driven reconnection experiments. The measurements are in good agreement with first-principles particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and NLUF Grant DE-SC0008655.
Energy Confinement of High-Density Pellet-Fueled Plasmas in the Alcator C Tokamak
NASA Astrophysics Data System (ADS)
Greenwald, M.; Gwinn, D.; Milora, S.; Parker, J.; Parker, R.; Wolfe, S.; Besen, M.; Camacho, F.; Fairfax, S.; Fiore, C.; Foord, M.; Gandy, R.; Gomez, C.; Granetz, R.; Labombard, B.; Lipschultz, B.; Lloyd, B.; Marmar, E.; McCool, S.; Pappas, D.; Petrasso, R.; Pribyl, P.; Rice, J.; Schuresko, D.; Takase, Y.; Terry, J.; Watterson, R.
A series of pellet-fueling experiments has been carried out on the Alcator C tokamak. High-speed hydrogen pellets penetrate to within a few centimeters of the magnetic axis, raise the plasma density, and produce peaked density profiles. Energy confinement is observed to increase over similar discharges fueled only by gas puffing. In this manner record values of electron density, plasma pressure, and Lawson number (n τ) have been achieved.
Structure of the plasmapause from ISEE 1 low-energy ion and plasma wave observations
NASA Technical Reports Server (NTRS)
Nagai, T.; Horwitz, J. L.; Anderson, R. R.; Chappell, C. R.
Low-energy ion pitch angle distributions are compared with plasma density profiles in the near-earth magnetosphere using ISEE 1 observations. The classical plasmapause determined by the sharp density gradient is not always observed in the dayside region, whereas there almost always exists the ion pitch angle distribution transition from cold, isotropic to warm, bidirectional, field-aligned distributions. In the nightside region the plasmapause density gradient is typically found, and it normally coincides with the ion pitch angle distribution transition. The sunward motion of the plasma is found in the outer part of the 'plasmaspheric' plasma in the dusk bulge region.
An Exact Calculation of Electron-Ion Energy Splitting in a Hot Plasma
Singleton, Robert L
In this brief report, I summarize the rather involved recent work of Brown, Preston, and Singleton (BPS). In Refs. [2] and [3], BPS calculate the energy partition into ions and electrons as a charged particle traverses a non-equilibrium two-temperature plasma. These results are exact to leading and next-to-leading order in the plasma coupling g, and are therefore extremely accurate in a weakly coupled plasma. The new BPS calculations are compared with the more standard work of Fraley et al. [12]. The results differ substantially at higher temperature when T{sub I} {ne} T{sub e}.
Energy deposition in parallel-plate plasma accelerators. Ph.D. Thesis
NASA Technical Reports Server (NTRS)
Dicapua, M. S.
To appraise the ratio of energy deposition into kinetic and thermal modes in plasma accelerators, a parallel-plate plasma accelerator has been operated in the quasi-steady mode with current pulses in the range of 10 to 100 kilo-amperes (kA), durations of the order of one millisecond, and argon mass flows up to 100 grams/sec. From photographic observations, spectroscopic measurements of velocity and electron density, and pressure measurements with a fast-rise piezoelectric transducer it is found that, for currents between 50 and 90 kA, the accelerated argon plasma is supersonic with ion velocities of 5 to 6 kilometers/sec.
Atomic mean excitation energies for stopping powers from local plasma oscillator strengths
NASA Technical Reports Server (NTRS)
Wilson, J. W.; Xu, Y. J.; Chang, C. K.; Kamaratos, E.
The stopping of a charged particle by isolated atoms is investigated theoretically using an 'atomic plasma' model in which atomic oscillator strengths are replaced by the plasma frequency spectrum. The plasma-frequency correction factor for individual electron motion proposed by Pines (1953) is incorporated, and atomic mean excitation energies are calculated for atoms through Sr. The results are compared in a graph with those obtained theoretically by Inokuti et al. (1978, 1981) and Dehmer et al. (1975) and with the experimental values compiled by Seltzer and Berger (1982): good agreement is shown.
PIV analysis of the homogeneity of energy deposition during development of a plasma actuator channel
NASA Astrophysics Data System (ADS)
Glazyrin, F. N.; Znamenskaya, I. A.; Mursenkova, I. V.; Naumov, D. S.; Sysoev, N. N.
Nonstationary velocity fields that arise during the development of flows behind shock (blast) waves initiated by pulsed surface sliding discharge in air at a pressure of (2-4) × 104 Pa have been experimentally studied by the particle image velocimetry (PIV) technique. Plasma sheets (nanosecond discharges slipping over a dielectric surface) were initiated on walls of a rectangular chamber. Spatial analysis of the shape of shock-wave fronts and the distribution of flow velocities behind these waves showed that the pulsed energy deposition is homogeneous along discharge channels of a plasma sheet, while the integral visible plasma glow intensity decreases in the direction of channel propagation.
Scrap tire recycling in Minnesota
Not Available
The author discusses the problems associated with scrap tires. For example, surface storing of scrap tires poses a fire hazard and the rainwater trapped in the tire casings is an ideal breeding ground for mosquitoes. Use as a fuel for energy production is unattractive as long as oil retails at its present low price. Past reclamation processes have not met expectations. Legislation alone is not the answer, because scrap tires cannot be regulated out of existence. However, the Minnesota state legislature has come up with an approach that seems to be successful. It has passed the Waste Tire Act, which not only formulates regulations but also provides funding for research and development. Thus, it has established a tire disposal fund for financing construction costs of tire recycling facilities. One of the outcomes was the construction of the St. Louis county Waste Tire Recycling Facility. Through a leasing arrangement with Minneapolis-based Rubber Elastomerics, Inc. (RRE), construction costs financed by the tire disposal fund eventually will be repaid by RRE to the fund. The arrangement is described in detail. By a process also described, RRE produces a product that can be used in thermoset and in thermoplastic compounds. The user can incorporate between 50 percent and 85 percent of the recycled product into a rubber or plastic compound without significantly affecting the physical properties of the compound.
ERIC Educational Resources Information Center
Sewall, Susan Breyer
Presents an activity that integrates science, environmental education, art, and social studies. Students identify and research an endangered species and construct a totem pole depicting the species using a recyclable material. (MDH)
A Practical Recycling Project . . .
ERIC Educational Resources Information Center
Durant, Raymond H.; Mikuska, James M.
Descirbes a school district's recycling program of aluminum lunch trays that are collected after their use. The trays are used as scrap metal in industrial education workshop and used for sand castings. (PS)
Recycle plastics into feedstocks
Kastner, H.; Kaminsky, W.
Thermal cracking of mixed-plastics wastes with a fluidized-bed reactor can be a viable and cost-effective means to meet mandatory recycling laws. Strict worldwide environmental statutes require the hydrocarbon processing industry (HPI) to develop and implement product applications and technologies that reuse post-consumer mixed-plastics waste. Recycling or reuse of plastics waste has a broad definition. Recycling entails more than mechanical regranulation and remelting of polymers for film and molding applications. A European consortium of academia and refiners have investigated if it is possible and profitable to thermally crack plastics into feedstocks for refining and petrochemical applications. Development and demonstration of pyrolysis methods show promising possibilities of converting landfill garbage into valuable feedstocks such as ethylene, propylene, BTX, etc. Fluidized-bed reactor technologies offer HPI operators a possible avenue to meet recycling laws, conserve raw materials and yield a profit. The paper describes thermal cracking for feedstocks and pyrolysis of polyolefins.
The Wheelabrator Falls story: Integrated recycling, highly efficient energy recovery, innovative use of by-products and timing to advance the state-of-the-art in integrated waste management
Felago, R.T.; Anderson, R.L.; Scanlon, P.J.
This paper discusses how significant state-of-the-art advancements in recycling, utilization of recycled materials and energy production will cut the template for future projects. A corollary benefit will be the enhancement of the concept of privatization of any plant, waste-to-energy, wastewater or biosolids processing, by providing an understanding of private initiation of the project, and the demonstration of a Company`s commitment through self-financing of the facility. All of these advancements point to the fact that waste-to-energy projects of the future will include some or all of these points from the Wheelabrator Falls Project: innovative on-site recycling; innovative utilization of mixed glass cullet; maximum post-combustion automatic recovery of ferrous metal; state-of-the-art boiler upgrades, including a super-efficient thermal cycle design refinements in the plant; specific innovations at falls; sequencing in the operations of the plant`s quality of operations; and expectations going forward.
Magnetic flux conversion and relaxation toward a minimum-energy state in S-1 spheromak plasmas
Janos, A.
S-1 Spheromak currents and magnetic fluxes have been measured with Rogowski coils and flux loops external to the plasma. Toroidal plasma currents up to 350 kA and spheromak configuration lifetimes over 1.0 msec have been achieved at moderate power levels. The plasma formation in the S-1 Spheromak device is based on an inductive transfer of poloidal and toroidal magnetic flux from a toroidal ''flux core'' to the plasma. Formation is programmed to guide the configuration into a force-free, minimum-energy Taylor state. Properly detailed programming of the formation process is found not to be essential since plasmas adjust themselves during formation to a final equilibrium near the Taylor state. After formation, if the plasma evolves away from the stable state, then distinct relaxation oscillation events occur which restore the configuration to that stable state. The relaxation process involves reconnection of magnetic field lines, and conversion of poloidal to toroidal magnetic flux (and vice versa) has been observed and documented. The scaling of toroidal plasma current and toroidal magnetic flux in the plasma with externally applied currents is consistent with the establishment of a Taylor state after formation. In addition, the magnetic helicity is proportional to that injected from the flux core, independent of how that helicity is generated.
Fossil Energy Program. Progress report for November 1979. [35 Wt % Illinois No. 6 coal with Wilsonville recycle solvent
Not Available
This report - the sixty-fourth of a series - is a compendium of monthly progress reports for the ORNL research and development programs that are in support of the increased utilization of coal and other fossil fuel alternatives to oil and gas as sources of clean energy. The projects reported this month include those for coal conversion development, materials engineering, a coal equipment test program, an atmospheric fluid bed combustor for cogeneration, engineering studies and technical support, process and program analysis, environmental assessment studies, magnetic beneficiation of dry pulverized coal, technical support to the TVA fluid bed combustion program, coal cogeneration/district heating plant assessment, chemical research and development, and technical support to major liquefaction projects.
Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere
Shimoyama, M.; Yau, A. W.; Oyama, K.-I.; Abe, T.
It is commonly believed that an energy transfer from thermal to suprathermal electrons (
Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere.
Shimoyama, M; Oyama, K-I; Abe, T; Yau, A W
It is commonly believed that an energy transfer from thermal to suprathermal electrons (
Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere
NASA Astrophysics Data System (ADS)
Shimoyama, M.; Oyama, K.-I.; Abe, T.; Yau, A. W.
It is commonly believed that an energy transfer from thermal to suprathermal electrons (
Nanoscale control of energy and matter in plasma-surface interactions: Toward energy- and matter-efficient nanotech
Ostrikov, K.
The approach to control the elementary processes of plasma-surface interactions to direct the fluxes of energy and matter at nano- and subnanometer scales is introduced. This ability is related to the solution of the grand challenge of directing energy and matter at nanoscales and is critical for the renewable energy and energy-efficient technologies for a sustainable future development. The examples of deterministic synthesis of self-organized arrays of metastable nanostructures in the size range beyond the reach of the present-day nanofabrication are considered to illustrate this possibility. By using precisely controlled and kinetically fast nanoscale transfer of energy and matter under nonequilibrium conditions and harnessing numerous plasma-specific controls of species creation, delivery to the surface, nucleation, and large-scale self-organization of nuclei and nanostructures, the arrays of metastable nanostructures can be created, arranged, stabilized, and further processed to meet the specific requirements of the envisaged applications.
Amey, E.B.; Kelly, T.D.
The first factor determining recyclability is the composition of the material itself. Metals, for example, can be reused with little or no loss in quality. Paper and rubber, by this criterion, are less recyclable. Each time paper is recycled, some cellulose fibers are broken. Shorter fibers can mean weaker paper of perceived lower quality and value. Vulcanizing is an irreversible chemical process that precludes recycling rubber in its original form. Both materials may be reused in other applications often of lower value than the original one. To be recyclable, the discarded material must have a collection infrastructure at the source of waste generation, at a central collection site, or at curbside. The recovered material must also have a market. If it is priced noncompetitively or no market exists, if it does not meet specifications, or if it requires special technology investments which cannot be recovered through future sales, the recovered material may be stockpiled or discarded rather than recycled. ?? 1996 International Association for Mathematical Geology.
Recent Ion Energy Distribution Observations on MST RFP Plasmas
NASA Astrophysics Data System (ADS)
Clark, Jerry; Titus, J. B.; Mezonlin, E. D.; Johnson, J. A., III; Almagri, A. F.; Andeson, J. A.
Ion energy distribution and temperature measurements have been made on the Madison Symmetric Torus (MST) using the Florida A&M University compact neutral particle analyzer (CNPA). The CNPA is a low energy (0.34-5.2 keV), high energy resolution (25 channels) neutral particle analyzer, with a radial view on MST. Recently, a retarding potential system was built to allow CNPA measurements to ensemble a complete ion energy distribution with high-energy resolution, providing insight into the dynamics of the bulk and fast ion populations. Recent work has also been done to improve the analysis techniques used to infer the ion temperature measurements, allowing us to understand temperature dynamics better during global magnetic reconnection events. Work supported in part by grants to FAMU and to UW from NSF and from Fusion Energy Sciences at DOE.
High-energy tail formation in an ion energy distribution function in the cylindrical Hall thruster plasma
NASA Astrophysics Data System (ADS)
Lim, Youbong; Kim, Holak; Park, Jaesun; Seon, Jongho; Choe, Wonho
Ion energy distribution functions (IEDFs) of individual ion species having different charge states (i.e. Xe+, Xe2+, Xe3+, etc.) in the Hall thruster plasma are obtained from the measured E × B probe spectrum by a novel inversion technique using the iterative Tikhonov regularization method. The obtained IEDFs show the existence of a high-energy tail in the cylindrical Hall thruster plasmas that is mainly due to Xe+ ions despite the presence of Xe2+ and Xe3+ ions with a large fraction. Ion dynamics inside the plasma was numerically investigated to demonstrate that the high-energy tail is due to nonlinear ion acceleration in the plasma oscillating at typically 100 to 500 kHz. We found that this oscillation driven by transit-time instability is responsible for the shift of the IEDF of the Xe+ ions toward the high-energy side, showing the formation of high-energy tail in the overall IEDF. It was also found that the Xe flow rate raised from 4 to 10 sccm increases the oscillation strength at the same frequency of 360 kHz, which can be applied to control of the shape of the IEDF.
Spatial distribution of low energy plasma at comet 67P from Rosetta RPC-LAP measurements
NASA Astrophysics Data System (ADS)
Edberg, Niklas J. T.; Eriksson, Anders I.; Odelstad, Elias; Vigren, Erik; Henri, Pierre; Lebreton, Jean-Pierre; Mandt, Kathleen; Nilsson, Hans; Carr, Chris; Cupido, Emanuele; Vallat, Claire; Altwegg, Kathrin
We present in situ measurements of the low energy plasma environment around comet 67P from the two Langmuir probes (LAP) on the Rosetta spacecraft, which form part of the Rosetta plasma consortium (RPC). RPC-LAP has operated almost continuously as Rosetta has orbited the comet at close distance (10-30 km) at low velocity (about 1 m/s) since August 2014. Using the RPC-LAP measurements we have produced global maps of the low energy plasma in the vicinity of 67P. Initial estimates indicate that the plasma density has reached values of several 100 cm^-3 and that the electron temperature has typically been in the range 5-10 eV, when the comet was beyond 2.5 AU from the sun. Photoionisation is the dominating process for producing the plasma around the comet while charge-exchange and impact ionisation may also contribute. The plasma environment has been found to be strongly coupled to the local neutral gas density, which in turn is coupled to which area on the comet is facing the sun. The northern summer neck-area of the comet outgasses more than other areas and above this region are the highest densities observed. In the southern winter and above the two main lobes of the comet body, the plasma density is lower. The plasma density is hence not determined by the solar wind, but by the outgassing from the comet. The 12.4-hour rotation period of the comet together with the varying latitude of the slow-moving Rosetta provide strong modulation of the RPC-LAP measurements. Besides orbiting the comet, Rosetta will also perform flybys of the comet in early 2015 when Rosetta will move to distances of several hundred kilometres from the nucleus. These flybys provide a cut-through view of the near-comet plasma environment, which will possibly give some insight to the solar-wind interaction with the cometary coma.
Performance of large electron energy filter in large volume plasma device
Singh, S. K.; Srivastava, P. K.; Awasthi, L. M.; Mattoo, S. K.; Sanyasi, A. K.; Kaw, P. K.; Singh, R.
This paper describes an in-house designed large Electron Energy Filter (EEF) utilized in the Large Volume Plasma Device (LVPD) [S. K. Mattoo, V. P. Anita, L. M. Awasthi, and G. Ravi, Rev. Sci. Instrum. 72, 3864 (2001)] to secure objectives of (a) removing the presence of remnant primary ionizing energetic electrons and the non-thermal electrons, (b) introducing a radial gradient in plasma electron temperature without greatly affecting the radial profile of plasma density, and (c) providing a control on the scale length of gradient in electron temperature. A set of 19 independent coils of EEF make a variable aspect ratio, rectangular solenoid producing a magnetic field (B{sub x}) of 100 G along its axis and transverse to the ambient axial field (B{sub z} ∼ 6.2 G) of LVPD, when all its coils are used. Outside the EEF, magnetic field reduces rapidly to 1 G at a distance of 20 cm from the center of the solenoid on either side of target and source plasma. The EEF divides LVPD plasma into three distinct regions of source, EEF and target plasma. We report that the target plasma (n{sub e} ∼ 2 × 10{sup 11} cm{sup −3} and T{sub e} ∼ 2 eV) has no detectable energetic electrons and the radial gradients in its electron temperature can be established with scale length between 50 and 600 cm by controlling EEF magnetic field. Our observations reveal that the role of the EEF magnetic field is manifested by the energy dependence of transverse electron transport and enhanced transport caused by the plasma turbulence in the EEF plasma.
Drag Reduction by Laser-Plasma Energy Addition in Hypersonic Flow
Oliveira, A. C.; Minucci, M. A. S.; Toro, P. G. P.; Chanes, J. B. Jr; Myrabo, L. N.
An experimental study was conducted to investigate the drag reduction by laser-plasma energy addition in a low density Mach 7 hypersonic flow. The experiments were conducted in a shock tunnel and the optical beam of a high power pulsed CO{sub 2} TEA laser operating with 7 J of energy and 30 MW peak power was focused to generate the plasma upstream of a hemispherical model installed in the tunnel test section. The non-intrusive schlieren optical technique was used to visualize the effects of the energy addition to hypersonic flow, from the plasma generation until the mitigation of the shock wave profile over the model surface. Aside the optical technique, a piezoelectric pressure transducer was used to measure the impact pressure at stagnation point of the hemispherical model and the pressure reduction could be observed.
Measuring the ion energy distribution using a retarding field energy analyzer in a plasma material interaction test stand
NASA Astrophysics Data System (ADS)
Christenson, Michael; Jung, Soonwook; Andruczyk, Daniel; Curreli, Davide; Ruzic, David
The Divertor Erosion and Vapor Shielding eXperiment (DEVeX) at the University of Illinois is a gas-puff driven, theta pinch plasma source that is used as a test stand for off-normal plasma events incident on materials in the edge and divertor regions of a tokamak. Ion temperatures and the resulting energy distribution are of vital importance in DEVeX, indicating the level of edge simulation. For this reason, a theta pinch has been applied as a source of external heating, along with a coaxial plasma accelerator as a pre-ionization source. In its most recent iteration, the accurate diagnosis of ion temperature will prove difficult using conventional methods, since diagnostics are difficult in a pulsed device for measuring the ion temperature range produced in DEVeX (~10-100 eV). A retarding field energy analyzer (RFEA) has been proposed to measure the ion energy distribution and will be compared to theoretical predictions for the ion temperature in the upgraded DEVeX system. Such a diagnostic tool would be less susceptible to external fields and would be suitable for ion temperatures on the order of 100 eV. The RFEA will serve as a diagnostic for the ThermoElectric-driven Liquid-metal plasma-facing Structures (TELS), and its further applications are discussed. In residence at Princeton Plasma Physics Laboratory.
Energy loss of tens keV charged particles traveling in the hot dense carbon plasma
NASA Astrophysics Data System (ADS)
Fu, ZhenGuo; Wang, ZhiGang; He, Bin; Li, DaFang; Zhang, Ping
The energy loss of charged particles, including electrons, protons, and α-particles with tens keV initial energy E 0, traveling in the hot dense carbon (C) plasma for densities from 2.281 to 22.81 g/cm3 and temperatures from 400 to 1500 eV is systematically and quantitatively studied by using the dimensional continuation method. The behaviors of different charged particles are readily distinguishable from each other. Firstly, because an ion is thousands times heavier than an electron, the penetration distance of the electron is much longer than that of proton and α-particle traveling in the plasma. Secondly, most energy of electron projectile with E 0 < 100 keV deposits into the electron species of C plasma, while for the cases of proton and α-particle with E 0 < 100 keV, about more than half energy transfers into the ion species of C plasma. A simple decreasing law of the penetration distance as a function of the plasma density is fitted, and different behaviors of each projectile particle can be clearly found from the fitted data. We believe that with the advanced progress of the present experimental technology, the findings shown here could be confirmed in ion-stopping experiments in the near future.
Energy distribution and heat transfer mechanisms in atmospheric pressure non-equilibrium plasmas
NASA Astrophysics Data System (ADS)
Nozaki, Tomohiro; Miyazaki, Yu; Unno, Yasuko; Okazaki, Ken
Energy distribution and heat transfer mechanisms in atmospheric pressure non-equilibrium plasmas were investigated extensively through energy balance analysis, emission spectroscopy of the rotational band of CH (A2Δ→X2Π), and gas chromatographic analysis. Two plasma sources were examined: methane-fed dielectric barrier discharge (DBD) and atmospheric pressure glow-discharge (APG). The DBD features filamentary microdischarges accompanied by surface discharge along a dielectric barrier. As a result, 60% of the input power was measured as heat transfer to the dielectric electrode, whereas 20% was to the metallic electrode. Consequently, feed gas average temperature was increased only by 20-40 K. On the other hand, rotational temperature of the corresponding emission region exceeded average gas temperature by 100 K. In APG, heat transfer to electrodes was dominated by formation of negative glow regardless of whether the electrode was covered by a dielectric. However, negative glow tended to be thinner and more intense when it formed on a metallic electrode, leading to slightly higher metallic heating. Rotational temperature in APG was close to average gas temperature since APG does not show radial localization of plasma. Energy efficiency for methane decomposition process to produce ethane, ethylene, and hydrogen was about 1% regardless of the plasma source. Energy distribution and heat transfer mechanisms depend strongly on the plasma spatial structure rather than flow fields or feed gas physical properties.
Heavy ion charge-state distribution effects on energy loss in plasmas
NASA Astrophysics Data System (ADS)
Barriga-Carrasco, Manuel D.
According to dielectric formalism, the energy loss of the heavy ion depends on its velocity and its charge density. Also, it depends on the target through its dielectric function; here the random phase approximation is used because it correctly describes fully ionized plasmas at any degeneracy. On the other hand, the Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler is used to determine its mean charge state
. This latter criterion implies that the mean charge state depends on the electron density and temperature of the plasma. Also, the initial charge state of the heavy ion is crucial for calculating
inside the plasma. Comparing our models and estimations with experimental data, a very good agreement is found. It is noticed that the energy loss in plasmas is higher than that in the same cold gas cases, confirming the well-known enhanced plasma stopping (EPS). In this case, EPS is only due to the increase in projectile effective charge Qeff, which is obtained as the ratio between the energy loss of each heavy ion and that of the proton in the same plasma conditions. The ratio between the effective charges in plasmas and in cold gases is higher than 1, but it is not as high as thought in the past. Finally, another significant issue is that the calculated effective charge in plasmas Qeff is greater than the mean charge state
, which is due to the incorporation of the BK charge distribution. When estimations are performed without this distribution, they do not fit well with experimental data.
Ion energy distribution near a plasma meniscus for multielement focused ion beams
Mathew, Jose V.; Bhattacharjee, Sudeep
The axial ion energy spread near a plasma meniscus for multielement focused ion beams is investigated experimentally in atomic and molecular gaseous plasmas of krypton, argon, and hydrogen by tailoring the magnetic field in the region. In the case of magnetic end plugging, the ion energy spread reduces by approx50% near the meniscus as compared to the bulk plasma, thereby facilitating beam focusing. A quadrupole filter can be used to control the mean energy of the ions. Comparison with standard Maxwellian and Druyvesteyn distributions with the same mean energy indicates that the ion energy distribution in the meniscus is deficient in the population of low and high energy tail ions, resulting in a Gaussian-like profile with a spread of approx4 and approx5 eV for krypton and argon ions, respectively. By carefully tuning the wave power, plasma collisionality, and the magnetic field in the meniscus, the spread can be made lower than that of liquid metal ion sources, for extracting focused ion beams of other elements with adequate current density, for research and applications in nanosystems
High-Energy Ions from Near-Critical Density Plasmas via Magnetic Vortex Acceleration
Nakamura, Tatsufumi; Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki
Ultraintense laser pulses propagating in near-critical density plasmas generate magnetic dipole vortex structures. In the region of decreasing plasma density, the vortex expands both in forward and lateral directions. The magnetic field pressure pushes electrons and ions to form a density jump along the vortex axis and induces a longitudinal electric field. This structure moves together with the expanding dipole vortex. The background ions located ahead of the electric field are accelerated to high energies. The energy scaling of ions generated by this magnetic vortex acceleration mechanism is derived and corroborated using particle-in-cell simulations.
Energy and momentum flow in electromagnetic fields and plasma. [solar wind-magnetospheric interaction
NASA Technical Reports Server (NTRS)
Parish, J. L.; Raitt, W. J.
The energy momentum tensor for a perfect fluid in a magnetic field is used to predict the momentum density, energy density, momentum flow, and energy flow of the fluid and the electromagnetic field. It is shown that taking the momentum flow from the energy momentum tensor, rather than starting with differential magnetohydrodynamic equations, can produce more accurate results on the basis of magnetic field data. It is suggested that the use of the energy momentum tensor has the potential for application to analysis of data from the more dynamic regions of the solar system, such as the plasma boundaries of Venus, the Jovian ionosphere, and the terrestrial magnetopause.
Spatial distribution of low-energy plasma around comet 67P/CG from Rosetta measurements
NASA Astrophysics Data System (ADS)
Edberg, N. J. T.; Eriksson, A. I.; Odelstad, E.; Henri, P.; Lebreton, J.-P.; Gasc, S.; Rubin, M.; André, M.; Gill, R.; Johansson, E. P. G.; Johansson, F.; Vigren, E.; Wahlund, J. E.; Carr, C. M.; Cupido, E.; Glassmeier, K.-H.; Goldstein, R.; Koenders, C.; Mandt, K.; Nemeth, Z.; Nilsson, H.; Richter, I.; Wieser, G. Stenberg; Szego, K.; Volwerk, M.
We use measurements from the Rosetta plasma consortium Langmuir probe and mutual impedance probe to study the spatial distribution of low-energy plasma in the near-nucleus coma of comet 67P/Churyumov-Gerasimenko. The spatial distribution is highly structured with the highest density in the summer hemisphere and above the region connecting the two main lobes of the comet, i.e., the neck region. There is a clear correlation with the neutral density and the plasma to neutral density ratio is found to be ˜1-2·10-6, at a cometocentric distance of 10 km and at 3.1 AU from the Sun. A clear 6.2 h modulation of the plasma is seen as the neck is exposed twice per rotation. The electron density of the collisionless plasma within 260 km from the nucleus falls off with radial distance as ˜1/r. The spatial structure indicates that local ionization of neutral gas is the dominant source of low-energy plasma around the comet.
Application of advanced plasma technology to energy materials and environmental problems
NASA Astrophysics Data System (ADS)
Kobayashi, Akira
Advanced plasma system has been proposed for various energy materials and for its application to environmental problems. The gas tunnel type plasma device developed by the author exhibits high energy density and also high efficiency. Regarding the application to thermal processing, one example is the plasma spraying of ceramics such as Al2O3 and ZrO2 as thermal barrier coatings (TBCs). The performances of these ceramic coatings are superior to conventional ones, namely, the properties such as the mechanical and chemical properties, thermal behavior and high temperature oxidation resistance of the alumina/zirconia thermal barrier coatings (TBCs) have been clarified and discussed. The ZrO2 composite coating has a possibility for the development of high functionally graded TBC. The results showed that the alumina/zirconia composite system exhibited an improvement of mechanical properties and oxidation resistance. Another application of gas tunnel type plasma to a functional material is the surface modification of metals. TiN films were formed in a short time of 5 s on Ti and its alloy. Also, thick TiN coatings were easily obtained by gas tunnel type plasma reactive spraying on any metals. Regarding the application to the environmental problems, the decomposition of CO2 gas is also introduced by applying the gas tunnel type plasma system.
Impacts of EV battery production and recycling
Gaines, L.; Singh, M.
Electric vehicles batteries use energy and produce environmental residuals when they are produced and recycled. This study estimates, for four selected battery types (sodium-sulfur, nickel-metal hydride, nickel-cadmium, and advanced lead-acid), the impacts of production and recycling of the materials used in electric vehicle batteries. These impacts are compared, with special attention to the locations of the emissions. It is found that the choice among batteries for electric vehicles involves tradeoffs among impacts. Nickel-cadmium and nickel-metal hydride batteries are similar, for example, but energy requirements for the production of cadmium electrodes may be higher than those for metal hydride electrodes, while the latter may be more difficult to recycle.
Measurements of energy distribution and thrust for microwave plasma coupling of electrical energy to hydrogen for propulsion
NASA Technical Reports Server (NTRS)
Morin, T.; Chapman, R.; Filpus, J.; Hawley, M.; Kerber, R.; Asmussen, J.; Nakanishi, S.
A microwave plasma system for transfer of electrical energy to hydrogen flowing through the system has potential application for coupling energy to a flowing gas in the electrothermal propulsion concept. Experimental systems have been designed and built for determination of the energy inputs and outputs and thrust for the microwave coupling of energy to hydrogen. Results for experiments with pressure in the range 100 microns-6 torr, hydrogen flow rate up to 1000 micronmoles/s, and total absorbed power to 700 w are presented.
Low-impedance plasma systems for generation of high-current low-energy electron beams
NASA Astrophysics Data System (ADS)
Agafonov, A. V.
The results of experimental investigation and numerical modeling of the generation of low-energy (tens of keV) high-current (up to tens of kA) electron beams in a low-impedance system consisting of a plasma-filled diode with a long plasma anode, an auxiliary hot cathode, and an explosive emission cathode. The low-current low-voltage beam from the auxiliary cathode in an external longitudinal magnetic field is used to produce a long plasma anode, which is simultaneously the channel of beam transportation by residual gas ionization. The high-current electron beam is formed from the explosive emission cathode placed in the preliminarily formed plasma. Numerical modeling is performed using the KARAT PIC code.
Model of enhanced energy deposition in a Z-pinch plasma
Velikovich, A. L.; Davis, J.; Thornhill, J. W.; Giuliani, J. L. Jr.; Rudakov, L. I.; Deeney, C.
In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. An analytical model describing this additional energy deposition based on the concept of macroscopic magnetohydrodynamic (MHD) turbulent pinch heating proposed by Rudakov and Sudan [Phys. Reports 283, 253 (1997)] is presented. The pinch plasma is modeled as a foam-like medium saturated with toroidal ''magnetic bubbles'' produced by the development of surface m=0 Rayleigh-Taylor and MHD instabilities. As the bubbles converge to the pinch axis, their magnetic energy is converted to thermal energy of the plasma through pdV work. Explicit formulas for the average dissipation rate of this process and the corresponding contribution to the resistance of the load, which compare favorably to the experimental data and simulation results, are presented. The possibility of using this enhanced (relative to Ohmic heating) dissipation mechanism to power novel plasma radiation sources and produce high K-shell yields using long current rise time machines is discussed. (c) 2000 American Institute of Physics.
Charge and energy transferred from a plasma jet to liquid and dielectric surfaces
NASA Astrophysics Data System (ADS)
Mussard, M. Dang Van Sung; Foucher, E.; Rousseau, A.
A key parameter in using plasma jets for biomedical applications is the transferred energy to the living tissues. The objective of this paper is to understand which parameters control the energy transfer from the plasma jet to a liquid or a dielectric surface. The plasma jet is flown with helium and ignited by a 600 Hz ac high voltage (up to 15 kV). Capacitors are connected to two measurement electrodes placed in the plasma source region, and under the sample. Charge and energy transferred are estimated by plotting Lissajous cycles; the number of bullets and the charge probability density function are also calculated. It is shown that the applied voltage and the gap (distance between the end of the tube and the sample) have a dramatic influence on the energy deposition on the sample as well as on the charge probability density function. Surprisingly, both gap distance and voltage have very little influence on the number of bullets reaching the sample per cycle. It is also shown that the conductivity of the liquid sample has almost no influence on the energy deposition and charge probability density function.
Electron residual energy due to stochastic heating in field-ionized plasma
NASA Astrophysics Data System (ADS)
Khalilzadeh, Elnaz; Yazdanpanah, Jam; Jahanpanah, Jafar; Chakhmachi, Amir; Yazdani, Elnaz
The electron residual energy originated from the stochastic heating in under-dense field-ionized plasma is investigated here. Initially, the optical response of plasma is modeled by using two counter-propagating electromagnetic waves. In this case, the solution of motion equation of a single electron indicates that by including the ionization, the electron with higher residual energy compared with that without ionization could be obtained. In agreement with chaotic nature of the motion, it is found that the electron residual energy will be significantly changed by applying a minor change in the initial conditions. Extensive kinetic 1D-3V particle-in-cell simulations have been performed in order to resolve full plasma reactions. In this way, two different regimes of plasma behavior are observed by varying the pulse length. The results indicate that the amplitude of scattered fields in a proper long pulse length is high enough to act as a second counter-propagating wave and trigger the stochastic electron motion. On the contrary, the analyses of intensity spectrum reveal the fact that the dominant scattering mechanism tends to Thomson rather than Raman scattering by increasing the pulse length. A covariant formalism is used to describe the plasma heating so that it enables us to measure electron temperature inside and outside of the pulse region.
Electron residual energy due to stochastic heating in field-ionized plasma
Khalilzadeh, Elnaz; Yazdanpanah, Jam Chakhmachi, Amir; Jahanpanah, Jafar; Yazdani, Elnaz
The electron residual energy originated from the stochastic heating in under-dense field-ionized plasma is investigated here. Initially, the optical response of plasma is modeled by using two counter-propagating electromagnetic waves. In this case, the solution of motion equation of a single electron indicates that by including the ionization, the electron with higher residual energy compared with that without ionization could be obtained. In agreement with chaotic nature of the motion, it is found that the electron residual energy will be significantly changed by applying a minor change in the initial conditions. Extensive kinetic 1D-3V particle-in-cell simulations have been performed in order to resolve full plasma reactions. In this way, two different regimes of plasma behavior are observed by varying the pulse length. The results indicate that the amplitude of scattered fields in a proper long pulse length is high enough to act as a second counter-propagating wave and trigger the stochastic electron motion. On the contrary, the analyses of intensity spectrum reveal the fact that the dominant scattering mechanism tends to Thomson rather than Raman scattering by increasing the pulse length. A covariant formalism is used to describe the plasma heating so that it enables us to measure electron temperature inside and outside of the pulse region.
Inductive Pulsed Plasma Thruster Model with Time-Evolution of Energy and State Properties
NASA Technical Reports Server (NTRS)
Polzin, Kurt A.; Sankaran, Kamesh
A model for pulsed inductive plasma acceleration is presented that consists of a set of circuit equations coupled to both a one-dimensional equation of motion and an equation governing the partitioning of energy. The latter two equations are obtained for the plasma current sheet by treating it as a single element of finite volume and integrating the governing equations over that volume. The integrated terms are replaced where necessary by physically-equivalent quantities that are calculated through the solution of other parts of the governing equation set. The model improves upon previous one-dimensional performance models by permitting the time-evolution of the energy and state properties of the plasma, the latter allowing for the tailoring of the model to different gases that may be chosen as propellants. The time evolution of the various energy modes in the system and the associated plasma properties, calculated for argon propellant, are presented to demonstrate the efficacy of the model. The model produces a result where efficiency is maximized at a given value of the electrodynamic scaling term known as the dynamic impedance parameter. Qualitatively and quantitatively, the model compares favorably with performance measured for two separate inductive pulsed plasma thrusters, with disagreements attributable to simplifying assumptions employed in the generation of the model solution.
Recycling of Reinforced Plastics
NASA Astrophysics Data System (ADS)
Adams, R. D.; Collins, Andrew; Cooper, Duncan; Wingfield-Digby, Mark; Watts-Farmer, Archibald; Laurence, Anna; Patel, Kayur; Stevens, Mark; Watkins, Rhodri
This work has shown is that it is possible to recycle continuous and short fibre reinforced thermosetting resins while keeping almost the whole of the original material, both fibres and matrix, within the recyclate. By splitting, crushing hot or cold, and hot forming, it is possible to create a recyclable material, which we designate a Remat, which can then be used to remanufacture other shapes, examples of plates and tubes being demonstrated. Not only can remanufacturing be done, but it has been shown that over 50 % of the original mechanical properties, such as the E modulus, tensile strength, and interlaminar shear strength, can be retained. Four different forms of composite were investigated, a random mat Glass Fibre Reinforced Plastic (GFRP) bathroom component and boat hull, woven glass and carbon fibre cloth impregnated with an epoxy resin, and unidirectional carbon fibre pre-preg. One of the main factors found to affect composite recyclability was the type of resin matrix used in the composite. Thermoset resins tested were shown to have a temperature range around the Glass Transition Temperature (Tg) where they exhibit ductile behaviour, hence aiding reforming of the material. The high-grade carbon fibre prepreg was found to be less easy to recycle than the woven of random fibre laminates. One method of remanufacturing was by heating the Remat to above its glass transition temperature, bending it to shape, and then cooling it. However, unless precautions are taken, the geometric form may revert. This does not happen with the crushed material.
Recycler lattice for Project X at Fermilab
Xiao, Meiqin; Johnson, David E.; /Fermilab
Project X is an intense proton source that provides beam for various physics programs. The source consists of an 8 GeV H- superconducting linac that injects into the Fermilab Recycler where H- are converted to protons. Protons are provided to the Main Injector and accelerated to desired energy (in the range 60-120 GeV) or extracted from the Recycler for the 8 GeV program. A long drift space is needed to accommodate the injection chicane with stripping foils. The Recycler is a fixed 8 GeV kinetic energy storage ring using permanent gradient magnets. A phase trombone straight section is used to control the tunes. In this paper, the existing FODO lattice in RR10 straight section being converted into doublet will be described. Due to this change, the phase trombone straight section has to be modified to bring the tunes to the nominal working point. A toy lattice of recycler ring is designed to simulate the end-shim effects of each permanent gradient magnet to add the flexibility to handle the tune shift to the lattice during the operation of 1.6E14 with KV distribution of the proton beam to give {approx}0.05 of space charge tune shift. The comparison or the combinations of the two modification ways for the Recycler ring lattice will be presented also in this paper.
Lee, Jin-Yi; Moon, Yong-Jae; Kim, Kap-Sung; Raymond, John C.; Reeves, Katharine K.
We investigate seven eruptive plasma observations by Hinode/XRT. Their corresponding EUV and/or white light coronal mass ejection features are visible in some events. Five events are observed in several passbands in X-rays, which allows for the determination of the eruptive plasma temperature using a filter ratio method. We find that the isothermal temperatures vary from 1.6 to 10 MK. These temperatures are an average weighted toward higher temperature plasma. We determine the mass constraints of eruptive plasmas by assuming simplified geometrical structures of the plasma with isothermal plasma temperatures. This method provides an upper limit to the masses of the observed eruptive plasmas in X-ray passbands since any clumping causes the overestimation of the mass. For the other two events, we assume the temperatures are at the maximum temperature of the X-ray Telescope (XRT) temperature response function, which gives a lower limit of the masses. We find that the masses in XRT, ∼3 × 10{sup 13}-5 × 10{sup 14} g, are smaller in their upper limit than the total masses obtained by LASCO, ∼1 × 10{sup 15} g. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive plasma in X-rays. For four events, we find that the thermal conduction timescales are much shorter than the duration of eruption. This result implies that additional heating during the eruption may be required to explain the plasma observations in X-rays for the four events.
Plasma-surface interactions in TFTR D-T experiments
Owens, D.K.; Adler, H.; Alling, P.
TFTR has begun its campaign to study deuterium-tritium fusion under reactor-like conditions. Variable amounts of deuterium and tritium neutral beam power have been used to maximize fusion power, study alpha heating, investigate alpha particle confinement, and search for alpha driven plasma instabilities. Additional areas of study include energy and particle transport and confinement, ICRF heating schemes for DT plasmas, tritium retention, and fusion in high {beta}{sub p} plasmas. The majority of this work is done in the TFTR supershot confinement regime. To obtain supershots, extensive limiter conditioning using helium fueled ohmic discharges and lithium pellet injection into ohmic and neutral beam heated plasmas is performed, resulting in a low recycling limiter. The relationship between recycling and core plasma confinement has been studied by using helium, deuterium and high-Z gas puffs to simulate high recycling limiter conditions. These studies show that confinement in TFTR supershots is very sensitive to the influx of neutral particles at the plasma edge.
Plasma radiation diagnostics of the primary energy release region in solar flares
NASA Technical Reports Server (NTRS)
Smith, D. F.; Spicer, D. S.
The possibility is investigated that the plasma turbulence used in many recent models of the primary energy release and acceleration in solar flares should be detectable by radiation near the fundamental and second harmonic of the plasma frequency. Formulae are derived for fundamental emission due to the combination of ion-acoustic and Langmuir plasma turbulence and for second harmonic emission due to the combination of two Langmuir waves. These results are applied to recent primary energy release and acceleration models which shows that either such radiation should be detectable and possibly distinguishable with suitable microwave interferometers or that its absence places fairly stringent constraints on the possible level of Langmuir or Langmuir and ion-acoustic waves in these models.
Energy transport by energetic electrons released during solar flares. II - Current filamentation and plasma heating
NASA Technical Reports Server (NTRS)
Winglee, R. M.; Dulk, G. A.; Pritchett, P. L.
Two-dimensional electrostatic particle simulations are performed in order to investigate energy transport associated with the propagation of energetic electrons through a flaring flux tube. Results indicate that as the energetic electrons flow outward, a return current of ambient plasma electrons is drawn inward (to maintain quasi-neutrality) which can be spatially separate from the primary current carried by the energetic electrons. Return current electrons are shown to accumulate on either side of the acceleration region of the energetic electrons, and depletions of ambient plasma electrons develop in the return current regions. Plasma ions accelerate across the field lines to produce current closure or charge neutralization, achieving energies comparable to those of the energetic electrons.
High-energy 4{omega} probe laser for laser-plasma experiments at nova
Glenzer, S. H., LLNL
For the characterization of inertial confinement fusion plasmas we implemented a high-energy 4{omega} probe laser at the Nova laser facility. A total energy of > 50 Joules at 4{omega}, a focal spot size of order 100 {micro}m, and a pointing accuracy of 100 {micro}m was demonstrated for target shots. This laser provides intensities of up to 3 x 10{sup 14}W cm{sup -2} and therefore fulfills high-power requirements for laser-plasma interaction experiments. The 4{omega} probe laser is now routinely used for Thomson scattering. Successful experiments were performed in gas-filled hohlraums at electron densities of n{sub e} > 2 X 10{sup 21}cm{sup -3} which represents the highest density plasma so far being diagnosed with Thomson scattering.
Rab22a Regulates the Recycling of Membrane Proteins Internalized Independently of ClathrinV⃞
Weigert, Roberto; Yeung, Albert Chi; Li, Jean; Donaldson, Julie G.
Plasma membrane proteins that are internalized independently of clathrin, such as major histocompatibility complex class I (MHCI), are internalized in vesicles that fuse with the early endosomes containing clathrin-derived cargo. From there, MHCI is either transported to the late endosome for degradation or is recycled back to the plasma membrane via tubular structures that lack clathrin-dependent recycling cargo, e.g., transferrin. Here, we show that the small GTPase Rab22a is associated with these tubular recycling intermediates containing MHCI. Expression of a dominant negative mutant of Rab22a or small interfering RNA-mediated depletion of Rab22a inhibited both formation of the recycling tubules and MHCI recycling. By contrast, cells expressing the constitutively active mutant of Rab22a exhibited prominent recycling tubules and accumulated vesicles at the periphery, but MHCI recycling was still blocked. These results suggest that Rab22a activation is required for tubule formation and Rab22a inactivation for final fusion of recycling membranes with the surface. The trafficking of transferrin was only modestly affected by these treatments. Dominant negative mutant of Rab11a also inhibited recycling of MHCI but not the formation of recycling tubules, suggesting that Rab22a and Rab11a might coordinate different steps of MHCI recycling. PMID:15181155
Parker, B.
On March 31, the California Supreme Court decided the much awaited Rancho Mirage'' case (Waste Management of the Desert, Inc., and the City of Rancho Mirage v. Palm Springs Recycling Center, Inc.), and held that the California Integrated Waste Management Act of 1989 does not allow an exclusive franchise for the collection of recyclables not discarded by their owner.'' This ends a three-year slugfest between secondary materials processors in the state and municipalities and their franchised garbage haulers who also collect and process recyclables as part of their exclusive arrangement. Central to this nationally-watched litigation is a most fundamental question in waste management: at what point in time do articles in the solid waste stream become actual or potentially valuable secondary materials
Lula, J.W.; Bohnert, G.W.
As the automobile tire technology has grown and met the need for safer and more durable tires, stronger reinforcement and more chemically resistant rubber compounds have made recycling tires more difficult. In an effort to resolve this problem, techniques and equipment were developed to grind tires into small pieces, and new markets were sought to utilize the crumb rubber product streams from ground tires. Industrial combustion processes were modified to accept scrap tires as fuel. These efforts have been beneficial, steadily increasing the percentage of scrap tires recycled to about 10% in 1985, and reaching 72% in 1995. By the end of 1997, fully 100% of tires generated in the U.S. are expected to be recycled.
Study of Energy Conversion and Partitioning in the Magnetic Reconnection Layer in Laboratory and Space Plasmas
NASA Astrophysics Data System (ADS)
Yamada, M.
The essential feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy [1]. This talk addresses this key unresolved question; how is magnetic energy converted to plasma kinetic energy during reconnection? The mechanisms responsible for the energization of plasma particles in the magnetic reconnection layer have been investigated in the MRX device together with quantitative evaluation of conversion of magnetic energy to ions and electrons. An analysis is made in terms of two-fluid physics based on the measurements of two-dimensional profiles of 1) electric potential, 2) flow vectors of electrons and ions, and 3) the electron temperature, Te and the ion temperature, Ti in the layer [2,3]. It is shown that more than 50 % of magnetic energy is converted to plasma particles, of which 2/3 transferred to ions and 1/3 to electrons, at a remarkably fast speed (~0.2VA) in the reconnection layer [3]. In a reconnection region of effectively similar size in the Earth's magnetotail, the energy partition was recently measured during multiple passages of the Cluster satellites [4]. The half length of the tail reconnection layer (L) was estimated to be 2000-4000 km namely 3-6di; the scale length is very similar to the MRX case, L ~ 3di. Reconnection in the magneto-tail is driven by an external force, i.e., the solar wind, and the boundary conditions are very similar to the MRX setup. The observed energy partition is notably similar, namely, more than 50% of the magnetic energy flux is converted to the particle energy flux, which is dominated by the ion enthalpy flux, with smaller contributions from the electron enthalpy and heat flux. A broad implication will be discussed. Work supported by DOE, NASA, and NSF. Fig.1: Measured ion flow vectors in the reconnection plane with measured 2-D profile of the plasma potential φ_p. The thin lines are measured poloidal flux counters.[1] M. Yamada, R. Kulsrud, & H. Ji, Rev. Mod
Experimental investigation of opacity models for stellar interiors, inertial fusion, and high energy density plasmas
NASA Astrophysics Data System (ADS)
Bailey, James
Theoretical opacities are required for calculating energy transport in plasmas. In particular, understanding stellar interiors, inertial fusion, and Z-pinches depends on the opacities of mid-atomic-number elements in the 150-300 eV temperature range. These models are complex and experimental validation is crucial. For example, solar models presently disagree with helioseismology and one possible explanation is inadequate opacities. Testing these opacities requires a uniform plasma at temperatures high enough to produce the ion charge states that exist in the sun. Typical opacity experiments heat a sample using x-rays and measure the spectrally resolved transmission with a backlight. The difficulty grows as the temperature increases because the heating x-ray source must supply more energy and the backlighter source must be bright enough to overwhelm the plasma self emission. These problems were overcome using the dynamic hohlraum x-ray source at Sandia's Z facility to measure the transmission of a mixed Mg-Fe plasma heated above 150 eV. This capability will also advance opacity science for other high energy density plasmas. This tutorial describes opacity experiment challenges including accurate transmission measurements, plasma diagnostics, and quantitative model comparisons. The solar interior serves as a focal problem and Z facility experiments are used to illustrate the techniques. **In collaboration with C. Iglesias (LLNL), R. Mancini (U. Nevada), J.MacFarlane, I. Golovkin and P. Wang (Prism), C. Blancard, Ph. Cosse, G. Faussurier, F. Gilleron, and J.C. Pain (CEA), J. Abdallah Jr. (LANL), and G.A. Rochau and P.W. Lake (Sandia). ++Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.
Micro-scale Plasma Arc Gasification for Waste Treatment and Energy Production Project
NASA Technical Reports Server (NTRS)
Caraccio, Anne
As NASA continues to develop technology for spaceflight beyond low earth orbit, we must develop the right systems for sustaining human life on a long duration or planetary mission. Plasma arc gasification (PAG) is an energy efficient mechanism of waste management for power generation and synthetic gas(syngas) production.
On the lower bound of the internal energy of the one-component-plasma
Khrapak, S. A.; Khrapak, A. G.
A new simple yet accurate analytical estimate for the internal energy of the classical one-component-plasma is proposed. In the limit of weak coupling, it reduces to the Debye-Hückel result. In the opposite limit of strong coupling, the ion sphere approximation is recovered. The agreement with the accurate numerical results in the intermediate coupling regime is fairly good.
Electron energy distribution in a helium plasma created by nuclear radiations
NASA Technical Reports Server (NTRS)
Lo, R. H.; Miley, G. H.
An integral balance technique for calculation of the electron energy distribution in a radiation-induced plasma is described. Results predict W-values reasonably well and compare favorably with more complicated Monte-Carlo calculations. The distribution found differs from that in a normal electrical discharge and is of interest in radiation-pumped laser research.
Investigation of pulsed X-ray radiation of a plasma focus in a broad energy range
Savelov, A. S. Salakhutdinov, G. Kh.; Koltunov, M. V.; Lemeshko, B. D.; Yurkov, D. I.; Sidorov, P. P.
The results of the experimental investigations of the spectral composition of plasma focus X-ray radiation in the photon energy range of 1.5 keV-400 keV are presented. Three regions in the radiation spectrum where the latter is of a quasi-thermal nature with a corresponding effective temperature are distinguished.
Electromagnetic energy density manipulation and enhancement in a relativistic plasma: the role of relativistic nonlinearities
Pegoraro, F.
A tutorial presentation is given describing the nature and the effects of relativistic nonlinearities in a plasma and indicating how they can be exploited in order to manipulate and enhance locally the energy density of the electromagnetic fields. The mathematical formulation and the examples presented are chosen from results available in the scientific literature.
Impact of the Pedestal Plasma Density on ELM Dynamics and Energy Loss Scaling
NASA Astrophysics Data System (ADS)
Xu, X. Q.; Ma, J. F.; Li, G. Q.; BOUT++ Collaboration
The latest BOUT + + studies show an emerging understanding of ELM dynamics and the consistent collisionality scaling of ELM energy losses with ITPA multi-tokamak database. A series of BOUT + + simulations are conducted to investigate the scaling characteristics of the ELM energy losses vs collisionality via a density scan, while keeping the plasma cross-sectional shape, total stored energy, total plasma current, pressure profiles fixed. The neoclassical collisionality at peak gradient position increases by a factor of 3262 from 0.0019 to 6.197. The critical trend of linear simulations emerges as a transition from ballooning-dominated states at high collisionality to peeling-dominated states at low collsionality with decreasing density. Nonlinear BOUT + + simulations show a two-stage process of ELM crash evolution of (i) initial bursts of pressure blob and void creation and (ii) inward turbulence spreading as void propagation. The inward void propagation stirs the top of pedestal plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELM energy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. This work was performed for USDOE by LLNL under DE-AC52-07NA27344, LLNL LDRD project 12-ERD-022 and the China Natural Science Foundation under Contract No. 10721505. LLNL-ABS-656793.
Covalent bonding effect on the mean excitation energy of H2 with the local plasma model
NASA Technical Reports Server (NTRS)
Kamaratos, E.
Chemical bonding is taken into account explicitly in the determination of the mean excitation energy (I) for stopping power of H2 with the local plasma approximation by employing molecular electronic wave functions for H2 for the first time. This procedure leads to a new value for IH2 that is higher than all accepted experimental and theoretical values.
Plasma guns for controlled fusion at megagauss energy-densities
Turchi, Peter J; Roderick, Norman F; Degnan, James H; Frese, Michael H
Electron cyclotron current drive (ECCD) at a low power level has been used on Tore Supra to induce local perturbations of the current density profile. Regimes with strong MHD activity have been analysed, and compared with similar stable discharges, in order to investigate the possible causes of their instability and relate the evolution of the discharge to the localization of EC power deposition. Both co- and counter-current drive pulses have been applied to dominantly or fully non-inductive discharges, sustained by a lower hybrid current drive. Detailed reconstructions by current diffusion calculations have been performed and the error bars evaluated. This method has proved valuable for shedding light on the complex interplay between the evolutions of temperature and safety factor profiles in steady-state tokamak plasmas. The crucial role of the dynamic evolution of rational surfaces has been identified. Moreover, we demonstrate that the operational domain in which ECCD can be employed must cope with the overall current profile characteristics, in particular the position where the safety factor has a minimum.
Suppression and energy loss in Quark-Gluon Plasma
NASA Astrophysics Data System (ADS)
Djordjevic, M.
High momentum suppression of light and heavy flavor observables is considered to be an excellent probe of jet-medium interactions in QCD matter created at RHIC and LHC. Utilizing this tool requires accurate suppression predictions for different experiments, probes and experimental conditions, and their unbiased comparison with experimental data. We developed the dynamical energy loss formalism which takes into account both radiative and collision energy loss computed within the same theoretical framework, dynamical (as opposed to static) scattering centers, finite magnetic mass, running coupling and uses no free parameters in comparison with experimental data. Within this formalism, we provide predictions, and a systematic comparison with the experimental data, for a diverse set of probes, various centrality ranges and various collision energies at RHIC and LHC. We also provide clear qualitative and quantitative predictions for the upcoming LHC experiments. A comprehensive agreement between our predictions and experimental results suggests that our dynamical energy loss formalism can well explain the jet-medium interactions in QGP, which will be further tested by the obtained predictions for the upcoming data.
Efficient evaluation of collisional energy transfer terms for plasma particle simulations
NASA Astrophysics Data System (ADS)
Turrell, A. E.; Sherlock, M.; Rose, S. J.
Particle-based simulations, such as in particle-in-cell (PIC) codes, are widely used in plasma physics research. The analysis of particle energy transfers, as described by the second moment of the Boltzmann equation, is often necessary within these simulations. We present computationally efficient, analytically derived equations for evaluating collisional energy transfer terms from simulations using discrete particles. The equations are expressed as a sum over the properties of the discrete particles.
A low energy positron accumulator for the plasma confinement in a compact magnetic mirror trap
Higaki, Hiroyuki Kaga, Chikato; Nagayasu, Katsushi; Okamoto, Hiromi; Nagata, Yugo; Kanai, Yasuyuki; Yamazaki, Yasunori
A low energy positron accumulator was constructed at RIKEN for the purpose of confining an electron-positron plasma. The use of 5 mCi {sup 22}Na RI source with a standard solid Ne moderator and N{sub 2} buffer gas cooling resulted in a low energy positron yield of ∼ 3 × 10{sup 5} e+/s. So far, 2 × 10{sup 6} positrons have been accumulated in 120s.
Generation of microwave-induced plasmas in automotive exhaust gas mixtures using pulsed microwave energy.
Destefani, Carlos A; Siores, Elias; Murphy, Anthony B
Microwave energy at 2.45 GHz was applied to a mixture of exhaust gases from a petrol engine at atmospheric pressure. It was found that by pulsing the microwave energy with a 50% duty cycle, the average power required to sustain a microwave-induced plasma discharge was decreased by about 40%. The ratio of absorbed to incident power was unaffected. These findings were confirmed for pulse frequencies from 10 to 300 Hz. PMID:15007864
Characterization of electron kinetics regime with electron energy probability functions in inductively coupled hydrogen plasmas
NASA Astrophysics Data System (ADS)
Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y. S.
Electron kinetics regime is characterized with the evolution of electron energy probability functions (EEPFs) in inductively coupled hydrogen plasmas. Measurements on EEPFs are carried out with a radio-frequency-compensated single Langmuir probe at the center of a planar-type hydrogen plasma driven by 13.56 MHz wave frequency. Measured EEPFs deviate considerably from the Maxwellian distribution only at relatively high pressures (15-40 mTorr), and the effective electron temperature steeply decreases as the gas pressure increases. Such evolution of the EEPF shapes with pressures is discussed in the consideration of the electron energy relaxation length and various characteristic frequencies. It is found that the EEPFs show locally depleted electron energy distribution where the electron-molecule vibrational collision frequency exceeds the electron-electron collision frequency at the local kinetics regime, while the measured EEPF is not dependent on the vibrational collision frequency at the non-local kinetics regime. Variation of the EEPF shape with distance from the heating region at the local kinetics regime is also well explained in the context of the energy relaxation length and electron-molecule collision frequencies. This study indicates that the control of electron energy distribution should be carried out in the consideration of electron kinetic regime depending on the energy relaxation length for various hydrogen plasma sources.
The formation of reverse shocks in magnetized high energy density supersonic plasma flows
Lebedev, S. V. E-mail: firstname.lastname@example.com; Suttle, L.; Swadling, G. F.; Bennett, M.; Bland, S. N.; Burdiak, G. C.; Chittenden, J. P.; Grouchy, P. de; Hall, G. N.; Hare, J. D.; Kalmoni, N.; Niasse, N.; Patankar, S.; Smith, R. A.; Suzuki-Vidal, F.; Burgess, D.; Clemens, A.; Ciardi, A.; Sheng, L.; Yuan, J.; and others
A new experimental platform was developed, based on the use of supersonic plasma flow from the ablation stage of an inverse wire array z-pinch, for studies of shocks in magnetized high energy density physics plasmas in a well-defined and diagnosable 1-D interaction geometry. The mechanism of flow generation ensures that the plasma flow (Re{sub M} ∼ 50, M{sub S} ∼ 5, M{sub A} ∼ 8, V{sub flow} ≈ 100 km/s) has a frozen-in magnetic field at a level sufficient to affect shocks formed by its interaction with obstacles. It is found that in addition to the expected accumulation of stagnated plasma in a thin layer at the surface of a planar obstacle, the presence of the magnetic field leads to the formation of an additional detached density jump in the upstream plasma, at a distance of ∼c/ω{sub pi} from the obstacle. Analysis of the data obtained with Thomson scattering, interferometry, and local magnetic probes suggests that the sub-shock develops due to the pile-up of the magnetic flux advected by the plasma flow.
The Science and Technology Challenges of the Plasma-Material Interface for Magnetic Fusion Energy
NASA Astrophysics Data System (ADS)
Whyte, Dennis
The boundary plasma and plasma-material interactions of magnetic fusion devices are reviewed. The boundary of magnetic confinement devices, from the high-temperature, collisionless pedestal through to the surrounding surfaces and the nearby cold high-density collisional plasmas, encompasses an enormous range of plasma and material physics, and their integrated coupling. Due to fundamental limits of material response the boundary will largely define the viability of future large MFE experiments (ITER) and reactors (e.g. ARIES designs). The fusion community faces an enormous knowledge deficit in stepping from present devices, and even ITER, towards fusion devices typical of that required for efficient energy production. This deficit will be bridged by improving our fundamental science understanding of this complex interface region. The research activities and gaps are reviewed and organized to three major axes of challenges: power density, plasma duration, and material temperature. The boundary can also be considered a multi-scale system of coupled plasma and material science regulated through the non-linear interface of the sheath. Measurement, theory and modeling across these scales are reviewed, with a particular emphasis on establishing the use dimensionless parameters to understand this complex system. Proposed technology and science innovations towards solving the PMI/boundary challenges will be examined. Supported by US DOE award DE-SC00-02060 and cooperative agreement DE-FC02-99ER54512.
Recycling Lithium Carbonate/Lithium Hydroxide Waste
NASA Technical Reports Server (NTRS)
Flowers, J.; Flowers, J.
Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.
Optimization of electron cooling in the Recycler
Shemyakin, A.; Burov, A.; Carlson, K.; Prost, L.R.; Sutherland, M.; Warner, A.; /Fermilab
Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1A DC electron beam (as well as by a stochastic cooling system). The paper describes electron cooling improvements recently implemented: adjustments of electron beam line quadrupoles to decrease the electron angles in the cooling section and better stabilization and control of the electron energy.
A self-consistent view on plasma-neutral interaction near a wall: plasma acceleration by momentum removal and heating by cold walls
NASA Astrophysics Data System (ADS)
van Rooij, Gerard; den Harder, Niek; Minea, Teofil; Shumack, Amy; de Blank, H.; Plasma Physics Team
In plasma physics, material walls are generally regarded as perfect sinks for charged particles and their energy. A special case arises when the wall efficiently reflects the neutralized plasma particles (with a significant portion of their kinetic energy) and at the same time the upstream plasma is of sufficiently high density to yield strong neutral-ion coupling (i.e. reflected energy and momentum will not escape from the plasma). Under these conditions, plasma-surface interaction will feedback to the upstream plasma and a self-consistent view on the coupling between plasma and neutrals is required for correct prediction of plasma conditions and plasma-surface interaction. Here, an analytical and numerical study of the fluid equations is combined with experiments (in hydrogen and argon) to construct such a self-consistent view. It shows how plasma momentum removal builds up upstream pressure and causes plasma acceleration towards the wall. It also shows how energy reflection causes plasma heating, which recycles part of the reflected power to the wall and induces additional flow acceleration due to local sound speed increase. The findings are relevant as generic textbook example and are at play in the boundary plasma of fusion devices.
Detailed energy distributions in laser-produced plasmas of solid gold and foam gold planar targets
Dong, Yunsong; Zhang, Lu; Yang, Jiamin; Shang, Wanli
Foam gold was proposed to increase the laser to x-ray conversion efficiency due to its important applications. To understand the mechanism of x-ray enhancement, the detailed energy distributions and plasma profiles for laser-irradiated solid gold and foam gold targets were studied comparatively by hydrodynamic simulations using the code Multi-1D. It is confirmed that the radiation heat wave is subsonic for the normal solid gold target, while supersonic for the foam gold target. The shock wave, which is behind the supersonic radiation heat wave for the foam gold target, generates a plasma temperature gradient with high temperature near the shock wave front to produce an additional net outward radiation for enhancement of the x-ray emission. Much larger inward plasma velocity is also driven by the shock wave as an initial plasma velocity for the laser deposition and electron thermal conduct zone, which decreases the expanding plasma kinetic energy loss and helps to increase the x-ray radiation.
Ion energy-angle distribution functions at the plasma-material interface in oblique magnetic fields
Khaziev, Rinat; Curreli, Davide
The ion energy-angle distribution (IEAD) at the wall of a magnetized plasma is of fundamental importance for the determination of the material processes occurring at the plasma-material interface, comprising secondary emissions and material sputtering. Here, we present a numerical characterization of the IEAD at the wall of a weakly collisional magnetized plasma with the magnetic field inclined at an arbitrary angle with respect to the wall. The analysis has been done using two different techniques: (1) a fluid-Monte Carlo method, and (2) particle-in-cell simulations, the former offering a fast but approximate method for the determination of the IEADs, the latter giving a computationally intensive but self-consistent treatment of the plasma behavior from the quasi-neutral region to the material boundary. The two models predict similar IEADs, whose similarities and differences are discussed. Data are presented for magnetic fields inclined at angles from normal to grazing incidence (0°–85°). We show the scaling factors of the average and peak ion energy and trends of the pitch angle at the wall as a function of the magnetic angle, for use in the correlation of fluid plasma models to material models.
Ion Energy Distribution Measurements Downstream of the High Power Helicon Plasma Thruster with a Flux Conserving Nozzle Configuration
NASA Astrophysics Data System (ADS)
Slobodov, Ilia; Winglee, Robert; Prager, James; Ziemba, Tim; Race Roberson, B.
The high power helicon (HPH) deposits up to 40 kW of power into a plasma, generating a plasma beam with a measured source density of 1x10^20 m-3 and energies in the range of 20-40 eV. Recently, the arrangement of magnetic nozzles downstream of the plasma source has been modified in order to produce a flux conserving configuration. Retarded field energy analyzer (RFEA) measurements of the ion energy distribution functions at two locations downstream of the plasma source, 67 cm and 144 cm away, have been carried out. Data on the number density, ion velocity, and energy density of the plasma beam at these locations will be presented. An improvement in performance over the previous nozzle configuration is observed. Additionally, results suggest that the energy density of the beam does not decrease with distance from the source between the two locations.
Particle energy distributions and metastable atoms in transient low pressure interpulse microwave plasma
NASA Astrophysics Data System (ADS)
Pandey, Shail; Nath Patel, Dudh; Ram Baitha, Anuj; Bhattacharjee, Sudeep
The electron energies and its distribution function are measured in non-equilibrium transient pulsed microwave plasmas in the interpulse regime using a retarding field electron energy analyzer. The plasmas are driven to different initial conditions by varying the electromagnetic (EM) wave pulse duration, peak power, or the wave frequency. Two cases of wave excitation are investigated: (i) short-pulse (pulse duration, t w ~ 1 μs), high-power (~60 kW) waves of 9.45 GHz and (ii) medium-pulse (t w ~ 20 μs), and moderate power waves of ~3 kW at 2.45 GHz. It is found that high-power, short-duration pulses lead to a significantly different electron energy probability function (EEPF) in the interpulse phase—a Maxwellian with a bump on the tail, although the average energy per pulse (~60 mJ) is maintained the same in the two modes of wave excitation. Electrons with energies >250 eV are found to exist in the discharge in the both cases. Another subset of experiments is performed to delineate the effect of the wave frequency and the peak power on EEPF. A traveling wave tube (TWT) amplifier based microwave source for generating pulsed plasma (t w = 230 μs) in a wide frequency range (6-18 GHz) is employed for this purpose. Further experiments on measurements of metastable density using optical emission spectroscopy and ion energy analyzer have been carried out. By tailoring the EEPF of the transient plasma and metastable densities, new applications in plasma processing, chemistry and biology can be realized in the interpulse phase of the discharge.
Inductive pulsed plasma thruster model with time-evolution of energy and state properties
NASA Astrophysics Data System (ADS)
Polzin, K. A.; Sankaran, K.; Ritchie, A. G.; Reneau, J. P.
A model for pulsed inductive plasma acceleration is presented that consists of a set of circuit equations coupled to both a one-dimensional (1D) equation of motion and an equation governing the partitioning of energy. The latter two equations are obtained for the plasma current sheet by treating it as a single element of finite volume and integrating the governing equations over that volume. The integrated terms are replaced where necessary by physically equivalent approximations that are calculated through the solution of other parts of the governing equation set. The model improves upon previous 1D performance models by permitting the time-evolution of the temperature consistent with the time-varying energy flux into the plasma. The plasma state properties are also more realistically modelled and evolved in time, allowing for the tailoring of the model to different gases that may be chosen as propellants. Computational results for argon propellant are presented to demonstrate the efficacy of the model. The model produces a result where efficiency is maximized at a given value of the electrodynamic scaling term known as the dynamic impedance parameter. The scaling of different energy sinks as a function of the dynamic impedance parameter provides insight into the global energy partitioning in these types of accelerators. Results from the present model deviate from the previous version where temperature is selected as an input without regard for the energy that would be deposited to heat the gas to that temperature. Qualitatively and quantitatively, the model predicts specific impulse values that compare favourably with those measured for two separate inductive pulsed plasma thrusters. Efficiency is underpredicted in the regime where data are available, but the trends in the data and simulations follow similar trajectories that appear to be converging towards a predicted peak efficiency as the dynamic impedance parameter is increased.
Numerical Modeling and Testing of an Inductively-Driven and High-Energy Pulsed Plasma Thrusters
NASA Technical Reports Server (NTRS)
Parma, Brian
Pulsed Plasma Thrusters (PPTs) are advanced electric space propulsion devices that are characterized by simplicity and robustness. They suffer, however, from low thrust efficiencies. This summer, two approaches to improve the thrust efficiency of PPTs will be investigated through both numerical modeling and experimental testing. The first approach, an inductively-driven PPT, uses a double-ignition circuit to fire two PPTs in succession. This effectively changes the PPTs configuration from an LRC circuit to an LR circuit. The LR circuit is expected to provide better impedance matching and improving the efficiency of the energy transfer to the plasma. An added benefit of the LR circuit is an exponential decay of the current, whereas a traditional PPT s under damped LRC circuit experiences the characteristic "ringing" of its current. The exponential decay may provide improved lifetime and sustained electromagnetic acceleration. The second approach, a high-energy PPT, is a traditional PPT with a variable size capacitor bank. This PPT will be simulated and tested at energy levels between 100 and 450 joules in order to investigate the relationship between efficiency and energy level. Arbitrary Coordinate Hydromagnetic (MACH2) code is used. The MACH2 code, designed by the Center for Plasma Theory and Computation at the Air Force Research Laboratory, has been used to gain insight into a variety of plasma problems, including electric plasma thrusters. The goals for this summer include numerical predictions of performance for both the inductively-driven PPT and high-energy PFT, experimental validation of the numerical models, and numerical optimization of the designs. These goals will be met through numerical and experimental investigation of the PPTs current waveforms, mass loss (or ablation), and impulse bit characteristics.
Energy Confinement of both Ohmic and LHW Plasma on EAST
NASA Astrophysics Data System (ADS)
Yang, Yao; Gao, Xiang; EAST Team
Study on the characters of energy confinement in both Ohmic and lower hybrid wave (LHW) discharges on EAST is conducted and the linear Ohmic confinement (LOC), saturated ohmic confinement (SOC) and improved Ohmic confinement (IOC) regimes are investigated in this paper. It is observed that an improved confinement mode characterized by both a drop of Dα line intensity and an increase in line average density can be triggered by a gas puffing pulse.
The TELEC - A plasma type of direct energy converter. [Thermo-Electronic Laser Energy Converter for electric power generation
NASA Technical Reports Server (NTRS)
Britt, E. J.
The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.
Argonne explains nuclear recycling in 4 minutes
Currently, when using nuclear energy only about five percent of the uranium used in a fuel rod gets fissioned for energy; after that, the rods are taken out of the reactor and put into permanent storage. There is a way, however, to use almost all of the uranium in a fuel rod. Recycling used nuclear fuel could produce hundreds of years of energy from just the uranium we've already mined, all of it carbon-free. Problems with older technology put a halt to recycling used nuclear fuel in the United States, but new techniques developed by scientists at Argonne National Laboratory address many of those issues. For more information, visit http://www.anl.gov/energy/nuclear-energy.
Argonne explains nuclear recycling in 4 minutes
Currently, when using nuclear energy only about five percent of the uranium used in a fuel rod gets fissioned for energy; after that, the rods are taken out of the reactor and put into permanent storage. There is a way, however, to use almost all of the uranium in a fuel rod. Recycling used nuclear fuel could produce hundreds of years of energy from just the uranium we've already mined, all of it carbon-free. Problems with older technology put a halt to recycling used nuclear fuel in the United States, but new techniques developed by scientists at Argonne National Laboratory address many of those issues. For more information, visit http://www.anl.gov/energy/nuclear-energy.
Potential GTCC LLW sealed radiation source recycle initiatives
Fischer, D
This report suggests 11 actions that have the potential to facilitate the recycling (reuse or radionuclide) of surplus commercial sealed radiation sources that would otherwise be disposed of as greater-than-Class C low-level radioactive waste. The suggestions serve as a basis for further investigation and discussion between the Department of Energy, Nuclear Regulatory Commission, Agreement States, and the commercial sector. Information is also given that describes sealed sources, how they are used, and problems associated with recycling, including legal concerns. To illustrate the nationwide recycling potential, Appendix A gives the estimated quantity and application information for sealed sources that would qualify for disposal in commercial facilities if not recycle. The report recommends that the Department of Energy initiate the organization of a forum to explore the suggested actions and other recycling possibilities.
Recycling Decisions and Green Design.
ERIC Educational Resources Information Center
Lave, Lester B.; And Others
Explores the facts and perceptions regarding recycling, what can be done to make products more environmentally compatible, and how to think about recycling decisions in a more helpful way. (Contains 39 references.) (MDH)
Developing a plasma focus research training system for the fusion energy age
NASA Astrophysics Data System (ADS)
Lee, S.
The 3 kJ UNU/ICTP Plasma Focus Facility is the most significant device associated with the AAAPT (Asian African Association for Plasma Training). In original and modified/upgraded form it has trained generations of plasma focus (PF) researchers internationally, producing many PhD theses and peer-reviewed papers. The Lee Model code was developed for the design of this PF. This code has evolved to cover all PF machines for design, interpretation and optimization, for derivation of radiation scaling laws; and to provide insights into yield scaling limitations, radiative collapse, speed-enhanced and current-stepped PF variants. As example of fresh perspectives derivable from this code, this paper presents new results on energy transfers of the axial and radial phases of generalized PF devices. As the world moves inexorably towards the Fusion Energy Age it becomes ever more important to train plasma fusion researchers. A recent workshop in Nepal shows that demand for such training continues. Even commercial project development consultants are showing interest. We propose that the AAAPT-proven research package be upgraded, by modernizing the small PF for extreme modes of operation, switchable from the typical strong-focus mode to a slow-mode which barely pinches, thus producing a larger, more uniform plasma stream with superior deposition properties. Such a small device would be cost-effective and easily duplicated, and have the versatility of a range of experiments from intense multi-radiation generation and target damage studies to superior advanced-materials deposition. The complementary code is used to reference experiments up to the largest existing machine. This is ideal for studying machine limitations and scaling laws and to suggest new experiments. Such a modernized versatile PF machine complemented by the universally versatile code would extend the utility of the PF experience; so that AAAPT continues to provide leadership in pulsed plasma research training in
Modeling of plasma flow switches at low, intermediate and high energies
Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.; Roderick, N.; Turchi, P.
Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch's efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime.
Modeling of plasma flow switches at low, intermediate and high energies
Bowers, R.L.; Brownell, J.H.; Greene, A.E.; Peterson, D.L.; Roderick, N.; Turchi, P.
Inductively stored pulsed power technology has been used over the past thirty years to produce multi-megaamp currents to implode low inductance loads and produce x-radiation. Because of the large difference in timescales for the delivery of magnetic energy to the load and the desire for high power x-radiation output (short timescale for the implosion), most inductively stored systems require at least one opening switch. The design and understanding of fast, efficient opening switches for multi-megaamp systems represents a long standing problem in pulsed power research. The Los Alamos Foil Implosion Project uses inductively stored magnetic energy to implode thin metallic liners. A plasma flow switch (PFS) has been investigated as the final pulse shaping step for this systems. The PFS consists of a wire array and a barrier foil located upstream from the load region. Several stages can be identified in the performance of the plasma flow switch. These are: (1) the vaporization of the wire array; (2) the assembly of the initiated plasma on tie barrier foil to form the switch plasma; (3) the motion of the switch plasma down the coaxial barrel; and (4) current switching to the load (the actual switching stage). The fourth stage affects the switch`s efficiency, as well as the quality of the load implosion. Instabilities may develop during any of these four stages, and their presence may seriously degrade the structure of the switch plasma. Two primary criteria may be used to characterize good switching. The first is switching efficiency. A second criterion is transferred to the load during or after switching. This paper summarizes the computational design of the PFS experiments carried out on Pegasus 1. We conclude by considering the implications of these results for the design of a PFS for the higher energy regime (Procyon) regime.
INEL metal recycle annual report, FY-94
Bechtold, T.E.
In 1992, the mission of the Idaho Chemical Processing Plant was changed from reprocessing of spent nuclear fuels to development of technologies for conditioning of spent nuclear fuels and other high-level wastes for disposal in a geologic repository. In addition, the Department of Energy (DOE) directed Idaho National Engineering Laboratory (INEL) to develop a program plan addressing the management of radioactive contaminated scrap metal (RSM) within the DOE complex. Based on discussions with the EM-30 organization, the INEL Metal Recycle program plan was developed to address all issues of RSM management. Major options considered for RSM management were engineered interim storage, land disposal as low-level waste, and beneficial reuse/recycle. From its inception, the Metal Recycle program has emphasized avoidance of storage and disposal costs through beneficial reuse of RSM. The Metal Recycle program plan includes three major activities: Site-by-site inventory of RSM resources; validation of technologies for conversion of RSM to usable products; and identification of parties prepared to participate in development of a RSM recycle business.
Software recycling at the Hanford Site
The Hanford Site was the first Department of Energy (DOE) complex to recycle excess software rather than dispose of it in the landfill. This plan, which took over a year to complete, was reviewed for potential legal conflicts, which could arise from recycling rather than disposal of software. It was determined that recycling was an approved method of destruction and therefore did not conflict with any of the licensing agreements that Hanford had with the software manufacturers. The Hanford Recycling Program Coordinator combined efforts with Pacific Northwest National Laboratory (PNNL) to recycle all Hanford software through a single contract, which went out for bid in January 1995. It was awarded to GreenDisk, Inc. located in Woodinville Washington and implemented in March 1995. The contract was later re-bid and awarded to EcoDisWGreenDisk in December 1998. The new contract included materials such as; software manuals, diskettes, tyvek wrapping, cardboard & paperboard packaging, compact disks (CDs), videotapes, reel-to-reel tapes, magnetic tapes, audio tapes, and many other types of media.
NASA Technical Reports Server (NTRS)
Cook, Joseph
Proposed system recovers and stores helium gas for reuse. Maintains helium at 99.99-percent purity, preventing water vapor from atmosphere or lubricating oil from pumps from contaminating gas. System takes in gas at nearly constant low back pressure near atmospheric pressure; introduces little or no back pressure into source of helium. Concept also extended to recycling of other gases.
ERIC Educational Resources Information Center
Rule, Audrey C.; Meyer, Mary Ann
This article presents an engaging activity in which high school students use a dichotomous key to guide the creation and classification of model insects from recycled plastic lids and containers. Besides teaching the use of a dichotomous key and the effect of evolutionary descent upon groupings of organisms, this activity focuses on an…
The project's purpose is to create a rating system for the ecological impacts of vehicles at the end of their life based on recyclability, toxic material content, and ultimate disposal. Each year, 10-11 million vehicles are retired from service in the United States. The vehi...
ERIC Educational Resources Information Center
Tillman, David A.
Three systems, operating at sufficient scale, produce fuels that may be alternatives to oil and gas. These three recycling systems are: Black Clawson Fiberclaim, Franklin, Ohio; Union Carbide, South Charleston, West Virginia; and Union Electric, St. Louis, Missouri. These produce a wet fuel, a pyrolytic gas, and a dry fuel, respectively. (BT)
ERIC Educational Resources Information Center
Hallowell, Anne; And Others
This study guide was designed to help teachers and students understand the problems surrounding solid wastes. It includes an overview of solid waste and recycling, a glossary, suggested activities and a list of resource publications, audiovisual materials and organizations. There are 19 activity suggestions included in this guide designed for use…
ERIC Educational Resources Information Center
Scott, Roger; And Others
This guide provides lessons that enable students to learn how important it is for each of us to take care of the environment by minimizing the problems caused by too much trash. In the 10 lessons included here, students and their families learn how they can be part of the solution by practicing source reduction and by reusing, recycling, and…
Progress in development of neutron energy spectrometer for deuterium plasma operation in KSTAR
Tomita, H. Yamashita, F.; Nakayama, Y.; Morishima, K.; Yamamoto, Y.; Sakai, Y.; Hayashi, S.; Kawarabayashi, J.; Iguchi, T.; Cheon, M. S.; Isobe, M.; Ogawa, K.
Two types of DD neutron energy spectrometer (NES) are under development for deuterium plasma operation in KSTAR to understand behavior of beam ions in the plasma. One is based on the state-of-the-art nuclear emulsion technique. The other is based on a coincidence detection of a recoiled proton and a scattered neutron caused by an elastic scattering of an incident DD neutron, which is called an associated particle coincidence counting-NES. The prototype NES systems were installed at J-port in KSTAR in 2012. During the 2012 and 2013 experimental campaigns, multiple shots-integrated neutron spectra were preliminarily obtained by the nuclear emulsion-based NES system.
A Cost-Effective Energy-Recovering Sustain Driving Circuit for ac Plasma Display Panels
NASA Astrophysics Data System (ADS)
Lim, Jae Kwang; Tae, Heung-Sik; Choi, Byungcho; Kim, Seok Gi
A new sustain driving circuit, featuring an energy-recovering function with simple structure and minimal component count, is proposed as a cost-effective solution for driving plasma display panels during the sustaining period. Compared with existing solutions, the proposed circuit reduces the number of semiconductor switches and reactive circuit components without compromising the circuit performance and gas-discharging characteristics. In addition, the proposed circuit utilizes the harness wire as an inductive circuit component, thereby further simplifying the circuit structure. The performance of the proposed circuit is confirmed with a 42-inch plasma display panel.
Screening Enhancement of Energy Equipartition in a Strongly Magnetized Nonneutral Plasma.
NASA Astrophysics Data System (ADS)
Bollinger, J.; Dubin, D.
An analogy is uncovered between the nuclear reaction rate in a dense plasma and the energy equipartition rate in a strongly-correlated (Γ = e^2 / aT ≫ 1) strongly-magnetized (κ = e^2 Ωc / \\overlinev T ≫ 1) nonneutral plasma. [Here \\overlinev = √T/m.] When κ ≫ 1, cyclotron energy is an adiabatic invariant. This energy is shared with other degrees of freedom only through rare close collisions that break the invariant. If Γ > 1, the probability of such close collisions is greatly enhanced because surrounding charges screen the colliding pair. In the regime Γ < κ^(2/5), we find that the equipartition rate ν defined by d Tc /dt = ν (T - T_c) (where Tc is the cyclotron temperature) is the rate without screening(M.E. Glinsky et al.), Phys. Fluids B 4, 1156 (1992). multiplied by an enhancement factor f (Γ). Interestingly, f(Γ ) is identical to the enhancement factor appearing in the theory of nuclear reaction rates in dense plasmas.(E.E. Salpeter and H. Van Horn, Ap. J. 155), 183 (1969). We present molecular dynamics simulations of equipartition. Rate enhancements of up to 10^10 are measured. The greatly enhanced rate may help to explain recent experiments that observed rapid equipartition in a Be^+ plasma.(Jensen et al., submitted to PRL. See also the adjacent poster.)
Mean excitation energies for stopping powers in various materials using local plasma oscillator strengths
NASA Technical Reports Server (NTRS)
Wilson, J. W.; Xu, Y. J.; Kamaratos, E.; Chang, C. K.
The basic model of Lindhard and Scharff, known as the local plasma model, is used to study the effects on stopping power of the chemical and physical state of the medium. Unlike previous work with the local plasma model, in which individual electron shifts in the plasma frequency were estimated empirically, he Pines correction derived for a degenerate Fermi gas is shown herein to provide a reasonable estimate, even on the atomic scale. Thus, the model is moved to a complete theoretical base requiring no empirical adjustments, as characteristic of past applications. The principal remaining error is in the overestimation of the low-energy absorption properties that are characteristic of the plasma model in the region of the atomic discrete spectrum, although higher-energy phenomena are accurately represented, and even excitation-to-ionization ratios are given to fair accuracy. Mean excitation energies for covalent-bonded gases and solids, for ionic gases and crystals, and for metals are calculated using first-order models of the bonded states.
An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy
Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.
We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using the method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. Lastly, the corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.
An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy
NASA Astrophysics Data System (ADS)
Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.
We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using the method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. The corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.
Dynamics of magnetic fields in high-energy-density plasmas for fusion and astrophysics
NASA Astrophysics Data System (ADS)
Gao, Lan; Ji, H.; Fox, W.; Hill, K.; Efthimion, P.; Nilson, P.; Igumenshchev, I.; Froula, D.; Betti, R.; Meyerhofer, D.; Fiksel, G.; Blackman, E.; Schneider, M.; Chen, H.; Smalyuk, V.; Li, H.; Casner, A.
An overview of our recent experimental and theoretical work on the dynamics of magnetic fields in high-energy-density plasmas will be presented. This includes: (1) precision mapping of the self-generated magnetic fields in the coronal plasma and the Nernst effect on their evolution, (2) characterizing the strong magnetic field generated by a laser-driven capacitor-coil target using ultrafast proton radiography, and (3) creating MHD turbulence in Rayleigh-Taylor unstable plasmas. The experimental results are compared with resistive MHD simulations providing a stringent test for their predictions. Applications in relevance to ignition target designs in inertial confinement fusion, material strength studies in high-energy-density physics, and astrophysical systems such as plasma dynamos and magnetic reconnection will be discussed. Future experiments proposed on the National Ignition Facility will be described. This material is supported in part by the Department of Energy National Nuclear Security Administration under Award No. DE-NA0001944, and the National Laser Users Facility under Grant No. DE-NA0002205.
Surface energy modification for biomedical material by corona streamer plasma processing to mitigate bacterial adhesion
NASA Astrophysics Data System (ADS)
Alhamarneh, Ibrahim; Pedrow, Patrick
Bacterial adhesion initiates biofouling of biomedical material but the processes can be reduced by adjusting the material's surface energy. The surface of surgical-grade 316L stainless steel (316L SS) had its hydrophilic property enhanced by processing in a corona streamer plasma reactor using atmospheric pressure Ar mixed with O2. Reactor excitation was 60 Hz ac high-voltage (<= 10 kV RMS) applied to a multi-needle-to-grounded-torus electrode configuration. Applied voltage and streamer current pulses were monitored with a broadband sensor system. When Ar/O2 plasma was used, the surface energy was enhanced more than with Ar plasma alone. Composition of the surface before and after plasma treatment was characterized by XPS. As the hydrophilicity of the treated surface increased so did percent of oxygen on the surface thus we concluded that reduction in contact angle was mainly due to new oxygen-containing functionalities. FTIR was used to identify oxygen containing groups on the surface. The aging effect that accompanies surface free energy adjustments was also observed.
An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy
Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.
We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using themore » method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. Lastly, the corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.« less
Efficient numerical modelling of the emittance evolution of beams with finite energy spread in plasma wakefield accelerators
NASA Astrophysics Data System (ADS)
Mehrling, T. J.; Robson, R. E.; Erbe, J.-H.; Osterhoff, J.
This paper introduces a semi-analytic numerical approach (SANA) for the rapid computation of the transverse emittance of beams with finite energy spread in plasma wakefield accelerators in the blowout regime. The SANA method is used to model the beam emittance evolution when injected into and extracted from realistic plasma profiles. Results are compared to particle-in-cell simulations, establishing the accuracy and efficiency of the procedure. In addition, it is demonstrated that the tapering of vacuum-to-plasma and plasma-to-vacuum transitions is a viable method for the mitigation of emittance growth of beams during their injection and extraction from and into plasma cells.
Impurity accumulation in plasma regimes with high energy confinement
NASA Astrophysics Data System (ADS)
Ran, L. B.; Roberts, D. E.; Yang, H. R.; Dodel, G.; Gentle, K.; Von Goeler, S.; Holzhauer, E.; Hübner, K.; Keilhacker, M.; Korotkov, A.; Luce, T. C.; Miura, Y.; Tsois, N.; Würz, H.; Fussmann, G.; Hofmann, J.; Janeschitz, G.; Krieger, K.; Müller, E. R.; Nolte, R.; Röhr, H.; Steuer, K. H.; Becker, G.; Bomba, B.; Bruhns, H.; Büchl, K.; Carlson, A.; Eberhagen, A.; Fahrbach, H.-U.; Gehre, O.; Gernhardt, J.; Giannone, L.; Von Gierke, G.; Glock, E.; Gruber, O.; Haas, G.; Herrmann, H.; Kaesdorf, S.; Karger, F.; Kaufmann, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lang, R.; Lee, P.; Lisitano, G.; Mast, F.; Mayer, H. M.; McCormick, K.; Meisel, D.; Mertens, V.; Murmann, H.; Neuhauser, J.; Niedermeyer, H.; Noterdaeme, J. M.; Poschenrieder, W.; Preis, R.; Rapp, H.; Rudyj, A.; Sandmann, W.; Schneider, F.; Schnider, U.; Siller, G.; Simmet, E.; Speth, E.; Söldner, F.; Stäbler, A.; Steinmetz, K.; Stroth, U.; Vollmer, O.; Zasche, D.
Investigations of impurity accumulation phenomena in ASDEX are reviewed. There are four different operating regimes where pronounced accumulation is observed and these regimes are also characterized by improved energy confinement. In particular, medium-Z metallic ions are involved in accumulation processes whereas low-Z ions appear almost unaffected. The rapid accumulation observed in the case of metallic ions may be explained by neoclassical inward drifts if we assume that the anomalous diffusion is sufficiently suppressed, some indication of this being found from laser blow-off studies. The present results, however, can only be partly explained by neoclassical theory, according to which accumulation of low-Z impurities should also occur. The temporal behaviour of accumulation and the retarding effect of proton dilution for collision dominated transport are also discussed. Finally, we conclude that the full benefits of improved energy confinement can be achieved only if the impurity influxes are kept to a sufficiently low level. Expressed in terms of concentrations under low confinement conditions we have to postulate, for ASDEX, concentrations ≲ 10 -4 for metals and ≲ 2% for all light impurities.
The plasma membrane as a capacitor for energy and metabolism.
Ray, Supriyo; Kassan, Adam; Busija, Anna R; Rangamani, Padmini; Patel, Hemal H
When considering which components of the cell are the most critical to function and physiology, we naturally focus on the nucleus, the mitochondria that regulate energy and apoptotic signaling, or other organelles such as the endoplasmic reticulum, Golgi, ribosomes, etc. Few people will suggest that the membrane is the most critical element of a cell in terms of function and physiology. Those that consider the membrane critical will point to its obvious barrier function regulated by the lipid bilayer and numerous ion channels that regulate homeostatic gradients. What becomes evident upon closer inspection is that not all membranes are created equal and that there are lipid-rich microdomains that serve as platforms of signaling and a means of communication with the intracellular environment. In this review, we explore the evolution of membranes, focus on lipid-rich microdomains, and advance the novel concept that membranes serve as "capacitors for energy and metabolism." Within this framework, the membrane then is the primary and critical regulator of stress and disease adaptation of the cell. PMID:26771520
Modeling of energy transfer between two crossing smoothed laser beams in a plasma with flow profile
NASA Astrophysics Data System (ADS)
Colaitis, A.; Hüller, S.; Tikhonchuk, V. T.; Pesme, D.; Duchateau, G.; Porzio, A.
We study the crossed beam energy transfer (CBET) between laser fields generated by optical smoothing methods. The energy transfer, as well as the angular distribution of the outgoing light fields are investigated for two incident smoothed laser beams in a plasma with a flow gradient, allowing for resonant transfer close to the sonic point. Simulations with the code HARMONY based on time-dependent paraxial light propagation are compared to simulations using a new approach based on paraxial complex geometrical optics (PCGO). Both approaches show good agreement for the average energy transfer past a short transient period, which is a promising result for the use of the PCGO method as a module within a hydrodynamics code to efficiently compute CBET in mm-scale plasma configurations. Statistical aspects related to role of laser speckles in CBET are considered via an ensemble of different phase plate realizations.
Modification of a nonlocal electron energy distribution in a bounded plasma.
DeJoseph, C A; Demidov, V I; Kudryavtsev, A A
It is demonstrated experimentally, in a pulsed discharge, that it is possible to modify the "tail" of a nonlocal electron energy distribution (EED) without significantly changing the electron density and temperature (mean energy). The EED tail is modified by changing the potential of a small portion of the plasma boundary and/or by changing the volume creation rate of electrons with energies in the range of the tail of the EED. The discussed effects are a direct result of the nonlocal nature of the EED and have applications to a number of basic research issues associated with discharges under nonequilibrium conditions. As an example, we discuss the possibility of utilizing these methods to measure electron impact excitation cross sections from the metastable states of atoms, which are difficult to measure by other means. The experiments have been conducted in an argon and argon-nitrogen pulsed rf inductively coupled plasma discharge. PMID:16241582
Observations of low-energy plasma composition from the ISEE-1 and SCATHA satellites
NASA Technical Reports Server (NTRS)
Horwitz, J. L.; Chappell, C. R.; Reasoner, D. L.; Craven, P. D.; Green, J. L.; Baugher, C. R.
This brief review is concerned with some of the initial measurements of low-energy ion properties conducted with the aid of ion composition detectors aboard the ISEE-1 and SCATHA satellites. ISEE-1 was launched in October 1977 into a highly elliptical orbit, while SCATHA was launched in January 1979 into a near geosynchronous orbit. Attention is given to the origin of low-energy plasma, the energization of ionospheric ions, the transport of ionospheric ions, and the loss of low-energy plasma from the magnetosphere. According to results obtained during the past several years, including the present ISEE-1 and SCATHA results, there are significant, and occasionally dominant, concentrations of He(+) and O(+) in various locations within the magnetosphere.
Low-energy energetic neutral atom imaging of Io plasma and neutral tori
NASA Astrophysics Data System (ADS)
Futaana, Yoshifumi; Barabash, Stas; Wang, Xiao-Dong; Wieser, Martin; Wieser, Gabriella S.; Wurz, Peter; Krupp, Norbert; Brandt, Pontus C.:son
Io's plasma and neutral tori play significant roles in the Jovian magnetosphere. We present feasibility studies of measuring low-energy energetic neutral atoms (LENAs) generated from the Io tori. We calculate the LENA flux between 10 eV and 3 keV. The energy range includes the corotational plasma flow energy. The expected differential flux at Ganymede distance is typically 103-105 cm-2 s-1 sr-1 eV-1 near the energy of the corotation. It is above the detection level of the planned LENA sensor that is to be flown to the Jupiter system with integration times of 0.01-1 s. The flux has strong asymmetry with respective to the Io phase. The observations will exhibit periodicities, which can be attributed to the Jovian magnetosphere rotation and the rotation of Io around Jupiter. The energy spectra will exhibit dispersion signatures, because of the non-negligible flight time of the LENAs from Io to the satellite. In 2030, the Jupiter exploration mission JUICE will conduct a LENA measurement with a LENA instrument, the Jovian Neutrals Analyzer (JNA). From the LENA observations collected by JNA, we will be able to derive characteristic quantities, such as the density, velocity, velocity distribution function, and composition of plasma-torus particles. We also discuss the possible physics to be explored by JNA in addition to the constraints for operating the sensor and analyzing the obtained dataset.
On energy and momentum conservation in particle-in-cell plasma simulation
NASA Astrophysics Data System (ADS)
Brackbill, J. U.
Particle-in-cell (PIC) plasma simulations are a productive and valued tool for the study of nonlinear plasma phenomena, yet there are basic questions about the simulation methods themselves that remain unanswered. Here we study energy and momentum conservation by PIC. We employ both analysis and simulations of one-dimensional, electrostatic plasmas to understand why PIC simulations are either energy or momentum conserving but not both, what role a numerical stability plays in non-conservation, and how errors in conservation scale with the numerical parameters. Conserving both momentum and energy make it possible to model problems such as Jeans'-type equilibria. Avoiding numerical instability is useful, but so is being able to identify when its effect on the results may be important. Designing simulations to achieve the best possible accuracy with the least expenditure of effort requires results on the scaling of error with the numerical parameters. Our results identify the central role of Gauss' law in conservation of both momentum and energy, and the significant differences in numerical stability and error scaling between energy-conserving and momentum-conserving simulations.
Recycling Behavior: A Multidimensional Approach
ERIC Educational Resources Information Center
Meneses, Gonzalo Diaz; Palacio, Asuncion Beerli
This work centers on the study of consumer recycling roles to examine the sociodemographic and psychographic profile of the distribution of recycling tasks and roles within the household. With this aim in mind, an empirical work was carried out, the results of which suggest that recycling behavior is multidimensional and comprises the undertaking…
Xanthos, Marino
Polypropylene (PP) is a widely used plastic with consumer applications ranging from food packaging to automotive parts, including car battery casings. To differentiate it from other recyclable plastics, it is designated as #5. Here, the factors contributing to PP recycling rates are briefly reviewed. Considerations include collection and separation efficiency, processing chemistry, and market dynamics for the products derived from recyclates. PMID:22879510
A new method on recycling coefficient measurement using impurity pellet injection in a large helical device
Nozato, Hideaki; Morita, Shigeru; Goto, Motoshi
Recycling coefficients of carbon, aluminum, and titanium were evaluated using a new technique combining impurity pellet injection with high-spatial resolution bremsstrahlung measurement in hydrogen and helium plasmas on the large helical device. The recycling coefficient of impurities was investigated by measuring absolute intensities with the visible bremsstrahlung array. The time evolution of the bremsstrahlung signals was modeled by an impurity transport code adjusting the diffusion coefficient, convective velocity, and recycling coefficient. As a result, a finite value of the recycling coefficient was required in the case of carbon, whereas aluminum and titanium were explained as nonrecycled particles. It was also clarified that the recycling coefficient of carbon had a larger value in hydrogen plasmas (R=0.5-0.65) than in helium plasmas (R=0-0.2), suggesting the formation of hydrogen molecules.
Energy loss of ions by electric-field fluctuations in a magnetized plasma
Nersisyan, Hrachya B.; Deutsch, Claude
The results of a theoretical investigation of the energy loss of charged particles in a magnetized classical plasma due to the electric-field fluctuations are reported. The energy loss for a test particle is calculated through the linear-response theory. At vanishing magnetic field, the electric-field fluctuations lead to an energy gain of the charged particle for all velocities. It has been shown that in the presence of strong magnetic field, this effect occurs only at low velocities. In the case of high velocities, the test particle systematically loses its energy due to the interaction with a stochastic electric field. The net effect of the fluctuations is the systematic reduction of the total energy loss (i.e., the sum of the polarization and stochastic energy losses) at vanishing magnetic field and reduction or enhancement at strong field, depending on the velocity of the particle. It is found that the energy loss of the slow heavy ion contains an anomalous term that depends logarithmically on the projectile mass. The physical origin of this anomalous term is the coupling between the cyclotron motion of the plasma electrons and the long-wavelength, low-frequency fluctuations produced by the projectile ion. This effect may strongly enhance the stochastic energy gain of the particle.
Recycling rubber wastes. (Latest citations from the Rubber and Plastics Research Association database). Published Search
The bibliography contains citations concerning research and innovations in the recycling of rubber wastes. Recycling methods and equipment, applications of recycled rubber, and energy recovery systems and performance are among the topics discussed. Recycling methods compared and contrasted with various rubber waste disposal techniques are also included. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
Implosion of an aluminum plasma jet onto a coaxial wire: A Z pinch with enhanced stability and energy transfer
Wessel, F.J.; Etlicher, B. ); Choi, P. )
We describe {ital Z}-pinch experiments imploding an aluminum-plasma jet onto a coaxial, micron-diameter wire. Spatially resolved x-ray pinhole images and time resolved x-ray data indicate that energy is supplied initially to the aluminum-jet plasma and subsequently transferred to the wire. The resultant pinch appears more uniform (stable) than a wire-only or jet-only pinch and demonstrates that an imploding-plasma liner will couple energy from a pulsed-power generator to a micron-diameter-sized plasma channel.
Injection of electrons with predominantly perpendicular energy into an area of toroidal field ripple in a tokamak plasma to improve plasma confinement
Ono, Masayuki; Furth, Harold
An electron injection scheme for controlling transport in a tokamak plasma. Electrons with predominantly perpendicular energy are injected into a ripple field region created by a group of localized poloidal field bending magnets. The trapped electrons then grad-B drift vertically toward the plasma interior until they are detrapped, charging the plasma negative. Calculations indicate that the highly perpendicular velocity electrons can remain stable against kinetic instabilities in the regime of interest for tokamak experiments. The penetration distance can be controlled by controlling the "ripple mirror ratio", the energy of the injected electrons, and their v.sub..perp. /v.sub.51 ratio. In this scheme, the poloidal torque due to the injected radial current is taken by the magnets and not by the plasma. Injection is accomplished by the flat cathode containing an ECH cavity to pump electrons to high v.sub..perp..
Predictions for the energy loss of light ions in laser-generated plasmas at low and medium velocities
NASA Astrophysics Data System (ADS)
Cayzac, W.; Bagnoud, V.; Basko, M. M.; Blažević, A.; Frank, A.; Gericke, D. O.; Hallo, L.; Malka, G.; Ortner, A.; Tauschwitz, An.; Vorberger, J.; Roth, M.
The energy loss of light ions in dense plasmas is investigated with special focus on low to medium projectile energies, i.e., at velocities where the maximum of the stopping power occurs. In this region, exceptionally large theoretical uncertainties remain and no conclusive experimental data are available. We perform simulations of beam-plasma configurations well suited for an experimental test of ion energy loss in highly ionized, laser-generated carbon plasmas. The plasma parameters are extracted from two-dimensional hydrodynamic simulations, and a Monte Carlo calculation of the charge-state distribution of the projectile ion beam determines the dynamics of the ion charge state over the whole plasma profile. We show that the discrepancies in the energy loss predicted by different theoretical models are as high as 20-30%, making these theories well distinguishable in suitable experiments.
Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas
NASA Technical Reports Server (NTRS)
Kwong, Victor H. S.
The laser ablation/ion storage facility at the UNLV Physics Department is dedicated to the study of atomic processes in low temperature plasmas. Our current program is directed to the study of charge transfer of multiply charged ions and neutrals that are of importance to astrophysics at energies less than 1 eV (about 10(exp 4) K). Specifically, we measure the charge transfer rate coefficient of ions such as N(2+), Si(3+), Si(3+), with helium and Fe(2+) with molecular and atomic hydrogen. All these ions are found in a variety of astrophysical plasmas. Their electron transfer reactions with neutral atoms can affect the ionization equilibrium of the plasma.
Spectroscopic Study of a Pulsed High-Energy Plasma Deflagration Accelerator
NASA Astrophysics Data System (ADS)
Loebner, Keith; Underwood, Thomas; Mouratidis, Theodore; Cappelli, Mark
Observations of broadened Balmer lines emitted by a highly-ionized transient plasma jet are presented. A gated CCD camera coupled to a high-resolution spectrometer is used to obtain chord-averaged broadening data for a complete cross section of the plasma jet, and the data is Abel inverted to derive the radial plasma density distribution. This measurement is performed over narrow gate widths and at multiple axial positions to provide high spatial and temporal resolution. A streak camera coupled to a spectrometer is used to obtain continuous-time broadening data over the entire duration of the discharge event (10-50 microseconds). Analyses of discharge characteristics and comparisons with previous work are discussed. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program, as well as the National Defense Science Engineering Graduate Fellowship.
Qualitative and quantitative analysis of endocytic recycling.
Reineke, James B; Xie, Shuwei; Naslavsky, Naava; Caplan, Steve
Endocytosis, which encompasses the internalization and sorting of plasma membrane (PM) lipids and proteins to distinct membrane-bound intracellular compartments, is a highly regulated and fundamental cellular process by which eukaryotic cells dynamically regulate their PM composition. Indeed, endocytosis is implicated in crucial cellular processes that include proliferation, migration, and cell division as well as maintenance of tissue homeostasis such as apical-basal polarity. Once PM constituents have been taken up into the cell, either via clathrin-dependent endocytosis (CDE) or clathrin-independent endocytosis (CIE), they typically have two fates: degradation through the late-endosomal/lysosomal pathway or returning to the PM via endocytic recycling pathways. In this review, we will detail experimental procedures that allow for both qualitative and quantitative assessment of endocytic recycling of transmembrane proteins internalized by CDE and CIE, using the HeLa cervical cancer cell line as a model system. PMID:26360033
Electron energy distribution functions in low-pressure oxygen plasma columns sustained by propagating surface waves
Stafford, L.; Margot, J.; Moisan, M.; Khare, R.; Donnelly, V. M.
Electron energy distribution functions (EEDFs) were measured in a 50 mTorr oxygen plasma column sustained by propagating surface waves. Trace-rare-gas-optical-emission spectroscopy was used to derive EEDFs by selecting lines to extract ''electron temperature''(T{sub e}) corresponding to either lower energy electrons that excite high-lying levels through stepwise excitation via metastable states or higher energy electrons that excite emission directly from the ground state. Lower energy T{sub e}'s decreased from 8 to 5.5 eV with distance from the wave launcher, while T{sub e}{approx_equal}6 eV for higher energy electrons and T{sub e}>20 eV for a high-energy tail. Mechanisms for such EEDFs are discussed.
Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus
Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.
The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy.
Nitrogen mass transfer models for plasma-based low-energy ion implantation
Zheng, Bocong; Wang, Kesheng; Zhang, Zhipeng; Che, Honglong; Lei, Mingkai
The nitrogen mass transfer process in plasma-based low-energy ion implantation (PBLEII) is theoretically and experimentally studied in order to explore the process mechanism of PBLEII and therefore to optimize the apparatus design and the process conditions. An electron cyclotron resonance (ECR) microwave discharge generates the nitrogen plasma with a high density of 10{sup 11}–10{sup 12} ions/cm{sup 3}, which diffuses downstream to the process chamber along the divergent magnetic field. The nitrogen ions in the plasma implant into the surface and transport to the matrix of an austenitic stainless steel under the low negative pulsed bias of −2 kV at a process temperature of 400 °C. A global plasma model is used to simulate the ECR microwave plasma discharge for a range of working pressures and microwave powers. The fluid models are adopted to calculate the plasma downstream diffusion, the sheath expansion and the low-energy ion implantation on the surface. A nonlinear kinetic discrete model is established to describe the nitrogen transport in the austenitic stainless steel and the results are compared with the experimental measurements. Under an average implantation current density of 0.3–0.6 mA/cm{sup 2}, the surface nitrogen concentration in the range from 18.5 to 29 at. % is a critical factor for the nitrogen transport in the AISI 304 austenitic stainless steel by PBLEII, which accelerates the implanted nitrogen diffusion inward up to 6–12 μm during a nitriding time of 4 h.
Operational Characteristics and Plasma Measurements in a Low-Energy FARAD Thruster
NASA Technical Reports Server (NTRS)
Polzin, K. A.; Best, S.; Rose, M. F.; Miller, R.; Owens, T.
Pulsed inductive plasma accelerators are spacecraft propulsion devices in which energy is stored in a capacitor and then discharged through an inductive coil. The device is electrodeless, inducing a plasma current sheet in propellant located near the face of the coil. The propellant is accelerated and expelled at a high exhaust velocity (order of 10 km/s) through the interaction of the plasma current with an induced magnetic field. The Faraday Accelerator with RF-Assisted Discharge (FARAD) thruster is a type of pulsed inductive plasma accelerator in which the plasma is preionized by a mechanism separate from that used to form the current sheet and accelerate the gas. Employing a separate preionization mechanism in this manner allows for the formation of an inductive current sheet at much lower discharge energies and voltages than those found in previous pulsed inductive accelerators like the Pulsed Inductive Thruster (PIT). In this paper, we present measurements aimed at quantifying the thruster's overall operational characteristics and providing additional insight into the nature of operation. Measurements of the terminal current and voltage characteristics during the pulse help quantify the output of the pulsed power train driving the acceleration coil. A fast ionization gauge is used to measure the evolution of the neutral gas distribution in the accelerator prior to a pulse. The preionization process is diagnosed by monitoring light emission from the gas using a photodiode, and a time-resolved global view of the evolving, accelerating current sheet is obtained using a fast-framing camera. Local plasma and field measurements are obtained using an array of intrusive probes. The local induced magnetic field and azimuthal current density are measured using B-dot probes and mini-Rogowski coils, respectively. Direct probing of the number density and electron temperature is performed using a triple probe.
Nanochannel Based Single Molecule Recycling
Lesoine, John F.; Venkataraman, Prahnesh A.; Maloney, Peter C.; Dumont, Mark
We present a method for measuring the fluorescence from a single molecule hundreds of times without surface immobilization. The approach is based on the use of electroosmosis to repeatedly drive a single target molecule in a fused silica nanochannel through a stationary laser focus. Single molecule fluorescence detected during the transit time through the laser focus is used to repeatedly reverse the electrical potential controlling the flow direction. Our method does not rely on continuous observation and therefore is less susceptible to fluorescence blinking than existing fluorescence-based trapping schemes. The variation in the turnaround times can be used to measure the diffusion coefficient on a single molecule level. We demonstrate the ability to recycle both proteins and DNA in nanochannels and show that the procedure can be combined with single-pair Förster energy transfer. Nanochannel-based single molecule recycling holds promise for studying conformational dynamics on the same single molecule in solution and without surface tethering. PMID:22662745
Integrated Recycling Test Fuel Fabrication
R.S. Fielding; K.H. Kim; B. Grover; J. Smith; J. King; K. Wendt; D. Chapman; L. Zirker
The Integrated Recycling Test is a collaborative irradiation test that will electrochemically recycle used light water reactor fuel into metallic fuel feedstock. The feedstock will be fabricated into a metallic fast reactor type fuel that will be irradiation tested in a drop in capsule test in the Advanced Test Reactor on the Idaho National Laboratory site. This paper will summarize the fuel fabrication activities and design efforts. Casting development will include developing a casting process and system. The closure welding system will be based on the gas tungsten arc burst welding process. The settler/bonder system has been designed to be a simple system which provides heating and controllable impact energy to ensure wetting between the fuel and cladding. The final major pieces of equipment to be designed are the weld and sodium bond inspection system. Both x-radiography and ultrasonic inspection techniques have been examine experimentally and found to be feasible, however the final remote system has not been designed. Conceptual designs for radiography and an ultrasonic system have been made.
Tritium recycling (processing) facility design
Metzler, J.; Le, T.
The maintenance of a nuclear weapons capability requires the periodic replacement of tritium contained in each of the weapons in the nuclear weapons stockpile because the radioactive decay of tritium reduces its quantity by about 5.5 percent per year. The Tritium Recycling Plant (TRP) performs the activities necessary to recover, purify, and recycle tritium returned from the field. Tritium is contained in vessels called reservoirs. The TRP also has the capability to conduct environmental tests to ensure the reliability and quality of the reservoirs. Currently, the U.S. has no source of new tritium. The proposed new TRP is an option the U.S. Department of Energy (U.S. DOE) is considering that could be collocated with the new Tritium Supply Plant if it is built at Oak Ridge, Pantex, Nevada Test Site, or Idaho National Engineering Laboratory. It will comply with applicable environment, safety and health, (ES&H) regulations and orders. If the new Tritium Supply Plant is built at the Savannah River Site, the existing TRP would be upgraded, as necessary. 3 refs., 4 figs.
Review of Burning Plasma Physics. Fusion Energy Sciences Advisory Committee (FESAC)
Berk, Herb; Betti, Riccardo; Dahlburg, Jill; Freidberg, Jeff; Hopper, Bick; Meade, Dale; Navritil, Jerry; Nevins, Bill; Ono, Masa; Perkins, Rip; Prager, Stewart; Schoenburg, Kurt; Taylor, Tony; Uckan, Nermin
The next frontier in the quest for magnetic fusion energy is the development of a basic understanding of plasma behavior in the regime of strong self-heating, the so called "burning plasma" regime. The general consensus in the fusion community is that the exploration of this frontier requires a new, relatively large experimental facility - a burning plasma experiment. The motivation, justification, and steps required to build such a facility are the primary focus of our report. The specific goals of the report are as follows. First, the report describes the critical scientific and engineering phenomena that are expected to arise for the first time, or else in a strongly modified form, in a burning plasma. Second, the report shows that the capabilities of existing experiments are inadequate to investigate these phenomena, thereby providing a major justification for a new facility. Third, the report compares the features and predicted performance of the three major next generation burning plasma experiments under current consideration (ITER-FEAT, FIRE, and IGNITOR), which are aimed at addressing these problems. Deliberately, no selection of the best option is made or attempted since such a decision involves complex scientific and cost issues that are beyond the scope of the present panel report. Fourth, the report makes specific recommendations regarding a process to move the burning plasma program forward, including a procedure for choosing the best option and the future activities of the Next Step Option (NSO) program. Fifth, the report attempts to provide a proper perspective for the role of burning plasmas with respect to the overall U.S. fusion program. The introduction provides the basic background information required for understanding the context in which the U.S. fusion community thinks about burning plasma issues. It "sets the stage" for the remainder of the report.
Identification of deep trap energies and influences of oxygen plasma ashing on semiconductor carrier lifetime
NASA Astrophysics Data System (ADS)
Koprowski, A.; Humbel, O.; Plappert, M.; Krenn, H.
We have performed an analytical study of the effects of oxygen plasma ashing processes in semiconductor device fabrication and its impact on minority carrier lifetime in high voltage semiconductor devices. Our work includes a critical background study of life time killing mechanisms by deep traps imparted into the semiconductor by barrel plasma ashing. The Elymat technique provides the opportunity to measure lifetime and diffusion length of minority carriers and surface photo voltage (SPV) measurement was used to analyse influences of process parameters such as photoresist, time budget and positioning in the process chamber. It was shown that in microwave plasma processes the diffusion length changes severely with tempering at 200 °C, whereas RF-plasma processes show a significant process time-dependence. Batch tools in general suffer from a strong first wafer effect which could be correlated with the static electrical parameters of the semiconductor devices. The trap identities were detected by using deep level transient spectroscopy and the chemical species of the traps has been proven by inductive coupled plasma mass spectrometry. The deep-bandgap trap energies are reliable fingerprints of the chosen process parameters such as process time and of resist-influences. By microwave plasma processes intrinsic Fe and FeB-complex levels were identified and a good agreement with the SPV-measurement and electrical device characteristic was shown. RF-plasma processes impart levels attributed to Pt levels and an additional level, which could be identified as a trap level probably forming a complex of Pt and H.
Pressure-driven, resistive magnetohydrodynamic interchange instabilities in laser-produced high-energy-density plasmas
Li, C. K.; Frenje, J. A.; Petrasso, R. D.; Seguin, F. H.; Amendt, P. A.; Landen, O. L.; Town, R. P. J.; Betti, R.; Knauer, J. P.; Meyerhofer, D. D.; Soures, J. M.
Recent experiments using proton backlighting of laser-foil interactions provide unique opportunities for studying magnetized plasma instabilities in laser-produced high-energy-density plasmas. Time-gated proton radiograph images indicate that the outer structure of a magnetic field entrained in a hemispherical plasma bubble becomes distinctly asymmetric after the laser turns off. It is shown that this asymmetry is a consequence of pressure-driven, resistive magnetohydrodynamic (MHD) interchange instabilities. In contrast to the predictions made by ideal MHD theory, the increasing plasma resistivity after laser turn-off allows for greater low-mode destabilization (m>1) from reduced stabilization by field-line bending. For laser-generated plasmas presented herein, a mode-number cutoff for stabilization of perturbations with m>{approx}[8{pi}{beta}(1+D{sub m}k{sub perpendicular}{sup 2}{gamma}{sub max}{sup -1})]{sup 1/2} is found in the linear growth regime. The growth is measured and is found to be in reasonable agreement with model predictions.
High Energy Plasmas, General Relativity and Collective Modes in the Vicinity of Black Holes*
NASA Astrophysics Data System (ADS)
Coppi, B.
Plasmas around black holes can take different equilibrium configurations^1 from those known from fluid theory as the vertical Lorentz compression due to plasma currents can overtake that of the gravitational force. In a disk with a ``seed'' magnetic field, axisymmetric modes as well as tri-dimensional spirals can be excited by the combined effects of the radial gradient of the plasma rotation frequency and of the plasma pressure gradient^2. The spirals' properties depend strongly on their vertical structure^3. Axisymmetric modes can produce vertical counter-flows of thermal energy and particles and be candidates for the origin of the winds emanating from disks in Active Galactic Nuclei (AGN's)^2. The excitation of radially localized density spirals corotating with the plasma near a black hole can provide an explanation for^4 the observed Quasi Periodic Oscillations (QPO's) of the X-ray emission from compact objects. Convective spiral modes^3 that are purely oscillatory in time and not localized radially can acquire their amplitudes from coupling to unstable modes and provide transport^3 of angular momentum toward the outer region of the disk structure.*Sponsored in part by the U.S. DOE. ^1B. Coppi and F. Rousseau, Ap. J., 641, 458 (2006). ^2B. Coppi, Europhys. Letters 82, 19001 (2008). ^3B. Coppi, MIT/LNS Report 08/08, submitted to A&A (2008). ^4B. Coppi and P. Rebusco, Paper P5.154, E.P.S. Conf. Pl. Phys. (Crete, 2008).
Effects of laser radiation field on energies of hydrogen atom in plasmas
NASA Astrophysics Data System (ADS)
Bahar, M. K.
In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence of laser radiation field within the Ehlotzky approximation using the asymptotic iteration method. The MGECSC potential includes four different potential forms in consideration of different sets of the parameters in the potential. By applying laser field, the total interaction potential of hydrogen atom embedded in plasmas converts to double well-type potential. The plasma screening effects under the influence of laser field as well as confinement effects of laser field on hydrogen atom in Debye and quantum plasmas are investigated by solving the Schrödinger equation with the laser-dressed MGECSC potential. It is resulted that since applying a monochromatic laser field on hydrogen atom embedded in a Debye and quantum plasma causes to shift in the profile of the total interaction potential, the confinement effects of laser field on hydrogen atom in plasmas modeled by the MGECSC potential change localizations of energy states.
Effects of laser radiation field on energies of hydrogen atom in plasmas
Bahar, M. K.
In this study, for the first time, the Schrödinger equation with more general exponential cosine screened Coulomb (MGECSC) potential is solved numerically in the presence of laser radiation field within the Ehlotzky approximation using the asymptotic iteration method. The MGECSC potential includes four different potential forms in consideration of different sets of the parameters in the potential. By applying laser field, the total interaction potential of hydrogen atom embedded in plasmas converts to double well-type potential. The plasma screening effects under the influence of laser field as well as confinement effects of laser field on hydrogen atom in Debye and quantum plasmas are investigated by solving the Schrödinger equation with the laser-dressed MGECSC potential. It is resulted that since applying a monochromatic laser field on hydrogen atom embedded in a Debye and quantum plasma causes to shift in the profile of the total interaction potential, the confinement effects of laser field on hydrogen atom in plasmas modeled by the MGECSC potential change localizations of energy states.
The impact of Hall physics on magnetized high energy density plasma jetsa)
NASA Astrophysics Data System (ADS)
Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.
Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (ne ˜ 1019 cm-3). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (˜1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches).
The impact of Hall physics on magnetized high energy density plasma jets
Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.
Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e} ∼ 10{sup 19} cm{sup −3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (∼1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)
Study of the energy inventory during asymmetric magnetic reconnection in a laboratory plasma
NASA Astrophysics Data System (ADS)
Yoo, Jongsoo; Yamada, Masaaki; Na, Ben; Jara-Almonte, Jonathan; Ji, Hantao; Fox, Will; Chien, Abe
The energy inventory of a magnetic reconnection layer is studied in a laboratory plasma with a significant density asymmetry across the current sheet. The upstream density ratio of about 7 is generated by the in-plane inductive electric field during the plasma formation in MRX. Compared to the symmetric case where the ion energy gain is about twice more than that of electrons, the ion energy gain becomes smaller and the electron energy gain is larger. The reduction in the ion energy gain is mainly caused by the asymmetric profile of the in-plane electrostatic potential, which is generated to balance the Lorentz force in the electron momentum equation. Since the out-of-plane electron fluid velocity on the high-density side is small due to the high density, the potential drop on the high-density side becomes also small. The potential drop on the low-density side is also smaller than expected from the general scaling (~B2 / n), since it is suppressed by a large density gradient across the low-density side separatrices. As a result, the ion energy gain from the in-plane electrostatic field is smaller than the symmetric case, thereby decreasing the total ion energy gain. Discussion on the electron energization process during asymmetric reconnection is also presented. This research is supported by DoE Contract Number DE-AC02-09CH11466.
Plasma treatment of polymer dielectric films to improve capacitive energy storage
NASA Technical Reports Server (NTRS)
Yializis, A.; Binder, M.; Mammone, R. J.
Demand for compact instrumentation, portable field equipment, and new electromagnetic weapons is creating a need for new dielectric materials with higher energy storage capabilities. Recognizing the need for higher energy storage capacitors, the Army Research Lab at Fort Monmouth, NJ, initiated a program a year ago to investigate potential methods for increasing the dielectric strength of polyvinylidene difluoride (PVDF) film, which is the highest energy density material commercially available today. Treatment of small area PVDF films in a CF4/O2 plasma showed that the dielectric strength of PVDF films can be increased by as much as 20 percent when treated in a 96 percent CF4/4 percent O2 plasma. This 44 percent increase in energy storage of a PVDF capacitor is significant considering that the treatment can be implemented in a conventional metallizing chamber, with minimum capital investment. The data shows that improved breakdown strength may be unique to PVDF film and the particular CF4/O2 gas mixture, because PVDF film treated with 100 percent CF4, 100 percent O2, Ar gas plasma, and electron irradiation shows no improvement in breakdown strength. Other data presented includes dissipation factor, dielectric constant, and surface tension measurements.
Discovery of an Io-correlated energy source for Io's hot plasma torus
NASA Astrophysics Data System (ADS)
Sandel, B. R.; Broadfoot, A. L.
Energy flowing into Io's hot plasma torus from a local-time correlated source and from an Io-related source are discussed, and a correlation of the brightness of the ansae of the torus with the apparent orbital phase of Io is reported. It is shown that the energy flows cause an azimuthal modulation of the brightness of the torus that is correlated with the position of Io, and the plasma downstream from Io is shown to be brighter in S III 685-A emission, which indicates a higher electron temperature. Differences in electron temperature inferred from spectral analyses account for all observed differences in brightness, implying that no change in the composition or density of the hot plasma occurs. The mechanism regulating the Io-related source is clearly distinct from the mechanism driving the local time source, although both draw on the same pool of energy, and the combination of the two sources is easily capable of supplying all the energy radiated by the torus.
Cladding and Duct Materials for Advanced Nuclear Recycle Reactors
Allen, Todd R.; Busby, Jeremy T; Klueh, Ronald L; Maloy, S; Toloczko, M
The expanded use of nuclear energy without risk of nuclear weapons proliferation and with safe nuclear waste disposal is a primary goal of the Global Nuclear Energy Partnership (GNEP). To achieve that goal the GNEP is exploring advanced technologies for recycling spent nuclear fuel that do not separate pure plutonium, and advanced reactors that consume transuranic elements from recycled spent fuel. The GNEP s objectives will place high demands on reactor clad and structural materials. This article discusses the materials requirements of the GNEP s advanced nuclear recycle reactors program.
A statistical analysis of the low-energy geosynchronous plasma environment. I - Electrons. II - Ions
NASA Technical Reports Server (NTRS)
Garrett, H. B.; Schwank, D. C.; Deforest, S. E.
Data on the geosynchronous plasma environment between approximately 30 eV and 80 keV are analyzed statistically. Nearly 50 days of 10 minute averages of the first four moments of the distribution function from low-energy plasma detectors on the ATS-5 and ATS-6 geosynchronous satellites were used. The data were studied in terms of occurrence frequency, local time variations, and response to geomagnetic activity. These techniques revealed marked differences in the ATS-5 and ATS-6 data bases. When translated into a 2-Maxwellian representation, it was found that (1) the ATS-6 data covered an energy range not covered by ATS-5 (between 1 and 50 eV) and (2) there was a definite change in the ion plasma between the ATS-5 and ATS-6 measurements. Simple expressions are derived to simulate the relationship between the four moments, and a model is presented, which takes into account the ATS-5 and ATS-6 plasma variations. Despite the differences in the ion data, the accuracy of the four-moment representation was found valid for characterizing the geosynchronous electron population.
Nanostructure protein repellant amphiphilic copolymer coatings with optimized surface energy by Inductively Excited Low Pressure Plasma.
Bhatt, Sudhir; Pulpytel, Jérome; Ceccone, Giacomo; Lisboa, Patricia; Rossi, François; Kumar, Virendra; Arefi-Khonsari, Farzaneh
Statistically designed amphiphilic copolymer coatings were deposited onto Thermanox, Si wafer, and quartz crystal microbalance (QCM) substrates via Plasma Enhanced Chemical Vapor Deposition of 1H,1H,2H,2H-perfluorodecyl acrylate and diethylene glycol vinyl ether in an Inductively Excited Low Pressure Plasma reactor. Plasma deposited amphiphilic coatings were characterized by Field Emission Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, Atomic Force Microscopy, and Water Contact Angle techniques. The surface energy of the coatings can be adjusted between 12 and 70 mJ/m(2). The roughness of the coatings can be tailored depending on the plasma mode used. A very smooth coating was deposited with a CW (continuous wave) power, whereas a rougher surface with R(a) in the range of 2 to 12 nm was deposited with the PW (pulsed wave) mode. The nanometer scale roughness of amphiphilic PFDA-co-DEGVE coatings was found to be in the range of the size of the two proteins namely BSA and lysozyme used to examine for the antifouling properties of the surfaces. The results show that the statistically designed surfaces, presenting a surface energy around 25 mJ/m(2), present no adhesion with respect to both proteins measured by QCM. PMID:22029599
Magnetic Reconnection of an Externally Applied Magnetic Field in a High-Energy Density Plasma
NASA Astrophysics Data System (ADS)
Fiksel, G.; Barnak, D.; Chang, P.-Y.; Hu, S. X.; Nilson, P. M.; Betti, R.; Fox, W.; Germaschewski, K.; Bhattacharjee, A.
An experiment on magnetic reconnection of an externally applied magnetic field in counter-propagating high-energy density plasmas was conducted on the OMEGA EP Laser System. Two counter-propagating plasma flows were created by irradiating oppositely placed plastic (CH) targets with 1.8-kJ, 2-ns laser beams. An external magnetic field was imposed perpendicular to the plasma flow by MIFEDS (magneto-inertial fusion electrical discharge system). The magnetic field has a null-x-point geometry with B = 5 T at the targets. The plasma interaction was imaged by laser-driven, fast-proton radiography. The radiography images demonstrate formation of a pair of counter-propagating magnetized ``ribbons'' that collide and reconnect at the midplane. The results will be compared with particle-in-cell simulations and interpreted with predictions from the DRACO code. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944, and NLUF Grant DE-SC0008655.
Kinetic Energy Oscillations during Disorder Induced Heating in an Ultracold Plasma
NASA Astrophysics Data System (ADS)
Langin, Thomas; McQuillen, Patrick; Strickler, Trevor; Pohl, Thomas; Killian, Thomas
Ultracold neutral plasmas of strontium are generated by photoionizing laser-cooled atoms at temperature TMOT ~ 10 mK and density n ~1016 m-3 in a magneto-optical trap (MOT). After photoionization, the ions heat to ~ 1 K by a mechanism known as Disorder Induced Heating (DIH). During DIH kinetic energy oscillations (KEO) occur at a frequency ~ 2ωpi , where ωpi is the plasma frequency, indicating coupling to collective modes of the plasma. Electron screening also comes into play by changing the interaction from a Coulomb to a Yukawa interaction. Although DIH has been previously studied, improved measurements combined with molecular dynamics (MD) simulations allow us to probe new aspects. We demonstrate a measurement of the damping of the KEO due to electron screening which agrees with the MD simulations. We show that the MD simulations can be used to fit experimental DIH curves for plasma density n, resulting in very accurate density measurements. Finally, we discuss how ion temperature measurements are affected by the non-thermal distribution of the ions during the early stages of DIH. This work was supported by the United States National Science Foundation and the Department of Energy (PHY-0714603), the Air Force Office of Scientific Research (FA9550- 12-1-0267), the Shell Foundation, and the Department of Defense (NDSEG Fellowship)
Ionization energy shift of characteristic K x-ray lines from high-Z materials for plasma diagnostics
Słabkowska, K.; Szymańska, E.; Polasik, M.; Pereira, N. R.; Rzadkiewicz, J.; Seely, J. F.; Weber, B. V.; Schumer, J. W.
The energy of the characteristic x-rays emitted by high atomic number atoms in a plasma that contains energetic electrons depends on the atom's ionization. For tungsten, the ionization energy shift of the L-lines has recently been used to diagnose the plasma's ionization; the change in energy of a K-line has been measured for iridium and observed for ytterbium. Here, we present detailed computations of the ionization energy shift to K-lines of these and an additional element, dysprosium; for these atoms, some K-lines nearly coincide in energy with K-edges of slightly lower Z atoms so that a change in transmission behind a K-edge filter betrays a change in energy. The ionization energy shift of such high-energy K-lines may enable a unique diagnostic when the plasma is inside an otherwise opaque enclosure such as hohlraums used on the National Ignition Facility.
Transport from the Recycler Ring to the Antiproton Source Beamlines
Xiao, M.; /Fermilab
In the post-NOvA era, the protons are directly transported from the Booster ring to the Recycler ring rather than the Main Injector. For Mu2e and g-2 project, the Debuncher ring will be modified into a Delivery ring to deliver the protons to both Mu2e and g-2 experiments. Therefore, it requires the transport of protons from the Recycler Ring to the Delivery ring. A new transfer line from the Recycler ring to the P1 beamline will be constructed to transport proton beam from the Recycler Ring to existing Antiproton Source beamlines. This new beamline provides a way to deliver 8 GeV kinetic energy protons from the Booster to the Delivery ring, via the Recycler, using existing beam transport lines, and without the need for new civil construction. This paper presents the Conceptual Design of this new beamline.
Laser ablation of electronic materials including the effects of energy coupling and plasma interactions
Zeng, Xianzhong
Many laser ablation applications such as laser drilling and micromachining generate cavity structures. The study of laser ablation inside a cavity is of both fundamental and practical significance. In this dissertation, cavities with different aspect ratios (depth/diameter) were fabricated in fused silica by laser micromachining. Pulsed laser ablation in the cavities was studied and compared with laser ablation on a flat surface. The formation of laser-induced plasmas in the cavities and the effects of the cavities on the ablation processes were investigated. The temperatures and electron number densities of the resulting laser-induced plasmas in the cavities were determined from spectroscopic measurements. Reflection and confinement effects by the cavity walls and plasma shielding were discussed to explain the increased temperature and electron number density with respect to increasing cavity aspect ratio. The temporal variations of the plasma temperature and electron number density inside the cavity decreased more rapidly than outside the cavity. The effect of laser energy on formation of a plasma inside a cavity was also investigated. Propagation of the shock wave generated during pulsed laser ablation in cavities was measured using laser shadowgraph imaging and compared with laser ablation on a flat surface. It is found that outside the cavity, after about 30 ns the radius of the expanding shock wave was proportional to t2/5, which corresponds to a spherical blast wave. The calculated pressures and temperatures of the shocked air outside of the cavities were higher than those obtained on the flat surface. Lasers with femtosecond pulse duration are receiving much attention for direct fabrication of microstructures due to their capabilities of high-precision ablation with minimal damage to the sample. We have also performed experimental studies of pulsed femtosecond laser ablation on the flat surface of silicon samples and compared results with pulsed nanosecond
Chemical and mechanical recycling of shredder fluff
Jody, B.J.; Daniels, E.J.; Bonsignore, P.V.; Shoemaker, E.L.
Each year, the secondary metals industry recovers about 55--60 million tons of prompt and obsolete scrap which is used in the production of finished steel products. The single largest source of this scrap is the obsolete automobile. The shredder industry recovers about 10--12 million ton/yr of ferrous scrap, most of which is from shredded automobiles. However, for each ton of steel recovered, over 500 lb of fluff are produced. Shredder fluff is comprised of the nonmetallic content of the automobile and other shredded materials, such as refrigerators, dryers, and dishwashers, which are commonly called white goods. The plastics content of shredder fluff is typically about 15--20% by weight and is expected to increase over the next decade due to the significant increase in the use of automotive plastics over the past 10--15 years. At present, shredder fluff is landfilled. The rapidly escalating landfilling cost, along with environmental concerns over the fate of this waste, poses a significant cost and liability to the shredder industry. Research is being carried out to identify and develop recycling technologies that will reduce the volume and the mass of shredder fluff going to landfills and to minimize its cost impact on the recycling of secondary metals. Previous research has focused on exploiting the plastics content of shredder fluff and other hydrocarbons present in fluff for secondary recycling (e.g., production of wood-products substitutes) and for quaternary recycling (e.g., energy generation). Limited work was also conducted on tertiary recycling (e.g., pyrolysis and gasification). Although the previous research has established the technical feasibility of most, if not all, of the alternatives that were examined, none have proven to be cost-effective. This paper describes some research at Argonne National Laboratory (ANL) to develop a process to recycle some of the fluff content, primarily the thermoplastics.
Chemical and mechanical recycling of shredder fluff
Jody, B.J.; Daniels, E.J.; Bonsignore, P.V.; Shoemaker, E.L.
Each year, the secondary metals industry recovers about 55--60 million tons of prompt and obsolete scrap which is used in the production of finished steel products. The single largest source of this scrap is the obsolete automobile. The shredder industry recovers about 10--12 million ton/yr of ferrous scrap, most of which is from shredded automobiles. However, for each ton of steel recovered, over 500 lb of fluff are produced. Shredder fluff is comprised of the nonmetallic content of the automobile and other shredded materials, such as refrigerators, dryers, and dishwashers, which are commonly called white goods. The plastics content of shredder fluff is typically about 15--20% by weight and is expected to increase over the next decade due to the significant increase in the use of automotive plastics over the past 10--15 years. At present, shredder fluff is landfilled. The rapidly escalating landfilling cost, along with environmental concerns over the fate of this waste, poses a significant cost and liability to the shredder industry. Research is being carried out to identify and develop recycling technologies that will reduce the volume and the mass of shredder fluff going to landfills and to minimize its cost impact on the recycling of secondary metals. Previous research has focused on exploiting the plastics content of shredder fluff and other hydrocarbons present in fluff for secondary recycling (e.g., production of wood-products substitutes) and for quaternary recycling (e.g., energy generation). Limited work was also conducted on tertiary recycling (e.g., pyrolysis and gasification). Although the previous research has established the technical feasibility of most, if not all, of the alternatives that were examined, none have proven to be cost-effective. This paper describes some research at Argonne National Laboratory (ANL) to develop a process to recycle some of the fluff content, primarily the thermoplastics.
Energy Loss of Heavy Quarks—A Signal of Plasma Properties
NASA Astrophysics Data System (ADS)
Aichelin, J.
The possible observables for studying the properties of a plasma of quarks and gluons (QGP), which is presumably created in ultrarelativistic heavy-ion collisions, are discussed. While the light mesons do not contain the desired information about the QGP phase due to the strong final hadronic interaction, the `heavy' mesons, i.e. those containing a c- or b- quark, are more useful. We demonstrate that our recent pQCD based approach for the energy loss of heavy quarks in a QGP combined with hydrodynamical model of Kolb and Heinz for the expansion of the plasma can successfully describe the variety of experimental data—as the transverse momentum spectra, R_{AA}, and the elliptic flow v_2 of heavy quarks—from RHIC to LHC energies.
Reduced entropic model for studies of multidimensional nonlocal transport in high-energy-density plasmas
Del Sorbo, D.; Feugeas, J.-L.; Nicolaï, Ph.; Olazabal-Loumé, M.; Dubroca, B.; Guisset, S.; Touati, M.; Tikhonchuk, V.
Hydrodynamic simulations of high-energy-density plasmas require a detailed description of energy fluxes. For low and intermediate atomic number materials, the leading mechanism is the electron transport, which may be a nonlocal phenomenon requiring a kinetic modeling. In this paper, we present and test the results of a nonlocal model based on the first angular moments of a simplified Fokker-Planck equation. This multidimensional model is closed thanks to an entropic relation (the Boltzman H-theorem). It provides a better description of the electron distribution function, thus enabling studies of small scale kinetic effects within the hydrodynamic framework. Examples of instabilities of electron plasma and ion-acoustic waves, driven by the heat flux, are presented and compared with the classical formula.
Experimental design to generate strong shear layers in a high-energy-density plasma
NASA Astrophysics Data System (ADS)
Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Gillespie, R. S.; Grosskopf, M. J.; Weaver, J. L.; Velikovich, A. L.; Visco, A.; Ditmar, J. R.
The development of a new experimental system for generating a strong shear flow in a high-energy-density plasma is described in detail. The targets were designed with the goal of producing a diagnosable Kelvin-Helmholtz (KH) instability, which plays an important role in the transition turbulence but remains relatively unexplored in the high-energy-density regime. To generate the shear flow the Nike laser was used to drive a flow of Al plasma over a low-density foam surface with an initial perturbation. The interaction of the Al and foam was captured with a spherical crystal imager using 1.86 keV X-rays. The selection of the individual targets components is discussed and results are presented.
Reduced entropic model for studies of multidimensional nonlocal transport in high-energy-density plasmas
NASA Astrophysics Data System (ADS)
Del Sorbo, D.; Feugeas, J.-L.; Nicolaï, Ph.; Olazabal-Loumé, M.; Dubroca, B.; Guisset, S.; Touati, M.; Tikhonchuk, V.
Hydrodynamic simulations of high-energy-density plasmas require a detailed description of energy fluxes. For low and intermediate atomic number materials, the leading mechanism is the electron transport, which may be a nonlocal phenomenon requiring a kinetic modeling. In this paper, we present and test the results of a nonlocal model based on the first angular moments of a simplified Fokker-Planck equation. This multidimensional model is closed thanks to an entropic relation (the Boltzman H-theorem). It provides a better description of the electron distribution function, thus enabling studies of small scale kinetic effects within the hydrodynamic framework. Examples of instabilities of electron plasma and ion-acoustic waves, driven by the heat flux, are presented and compared with the classical formula.
Estimates of magnetic flux, and energy balance in the plasma sheet during substorm expansion
NASA Technical Reports Server (NTRS)
Hesse, Michael; Birn, Joachim; Pulkkinen, Tuija
The energy and magnetic flux budgets of the magnetotail plasma sheet during substorm expansion are investigated. The possible mechanisms that change the energy content of the closed field line region which contains all the major dissipation mechanisms of relevance during substorms, are considered. The compression of the plasma sheet mechanism and the diffusion mechanism are considered and excluded. It is concluded that the magnetic reconnection mechanism can accomplish the required transport. Data-based empirical magnetic field models are used to investigate the magnetic flux transport required to account for the observed magnetic field dipolarizations in the inner magnetosphere. It is found that the magnetic flux permeating the current sheet is typically insufficient to supply the required magnetic flux. It is concluded that no major substorm-type magnetospheric reconfiguration is possible in the absence of magnetic reconnection.
Energy loss of argon in a laser-generated carbon plasma
Frank, A.; Harres, K.; Hoffmann, D. H. H.; Knobloch-Maas, R.; Nuernberg, F.; Pelka, A.; Schaumann, G.; Schoekel, A.; Schollmeier, M.; Schumacher, D.; Schuetrumpf, J.; Roth, M.; Blazevic, A.; Hessling, T.; Grande, P. L.; Kuznetsov, P. G.; Vatulin, V. V.; Vinokurov, O. A.; Schiwietz, G.
The experimental data presented in this paper address the energy loss determination for argon at 4 MeV/u projectile energy in laser-generated carbon plasma covering a huge parameter range in density and temperature. Furthermore, a consistent theoretical description of the projectile charge state evolution via a Monte Carlo code is combined with an improved version of the CasP code that allows us to calculate the contributions to the stopping power of bound and free electrons for each projectile charge state. This approach gets rid of any effective charge description of the stopping power. Comparison of experimental data and theoretical results allows us to judge the influence of different plasma parameters.
Laboratory Studies of Thermal Energy Charge Transfer of Silicon and Iron Ions in Astrophysical Plasmas
NASA Technical Reports Server (NTRS)
Kwong, Victor H. S.
Charge transfer at electron-volt energies between multiply charged atomic ions and neutral atoms and molecules is of considerable importance in astrophysics, plasma physics, and in particular, fusion plasmas. In the year covered by this report, several major tasks were completed. These include: (1) the re-calibration of the ion gauge to measure the absolute particle densities of H2, He, N2, and CO for our current measurements; (2) the analysis of data for charge transfer reactions of N(exp 2 plus) ion and He, H2, N2, and CO; (3) measurement and data analysis of the charge transfer reaction of (Fe(exp 2 plus) ion and H2; (4) charge transfer measurement of Fe(exp 2 plus) ion and H2; and (5) redesign and modification of the ion detection and data acquisition system for the low energy beam facility (reflection time of flight mass spectrometer) dedicated to the study of state select charge transfer.
Interaction of low-energy ions (< 10 eV) with polymethylmethacrylate during plasma treatment
NASA Astrophysics Data System (ADS)
Gröning, P.; Küttel, O. M.; Collaud-Coen, M.; Dietler, G.; Schlapbach, L.
Using in-situ X-ray photoelectron spectroscopy (XPS) we investigated the chemical modification of the polymethyl-methacrylate (PMMA) surfaces after plasma and low-energy ion beam treatment. A comparison between plasma and ion beam treatment has shown, that for noble gases both treatments produce absolutely the same modifications of the chemical composition on the PMMA surface. In reactive gases (O 2, N 2) molecular ions were found to decompose polar bonds at the polymer surface, but they do not contribute to the incorporation of reactive gas atoms. Reactive atomic ions and radicals are responsible for this incorporation. We found that in the case of PMMA less than three ions are needed to decompose the ester group (OCO) completely. Therefore, we conclude that the decomposition of the ester group by ions is a chemical and not a physical effect due to the kinetic energy of the ions.
Plasma Sputter-type Ion Source with Wire Electrodes for Low-energy Gallium Ion Extraction
Vasquez, M. Jr.; Kasuya, T.; Wada, M.; Maeno, S.; Miyamoto, N.
Low-energy ions of gallium (Ga) and argon (Ar) were extracted from a plasma sputter-type ion source system that utilized a tungsten (W) wire extractor geometry. The 90% transparent W wire extractor configuration had shown that the system was capable of producing an ion beam with the energy as low as 10 eV in a dc filament discharge and 50 eV in a radio frequency (rf) excited system. In the present investigation, Ar plasma was sustained in an ion source chamber through an inductively coupled 13.56 MHz rf power source. Negatively biased liquid Ga target suspended on a W reservoir was sputtered and postionized prior to extraction. Mass spectral analyses revealed a strong dependence of the Ga{sup +} current on the induced target bias.
Short-lived radioisotopes scaling with energy in plasma focus device
NASA Astrophysics Data System (ADS)
Kakavandi, Javad A.; Roshan, Mahmood V.; Habibi, Morteza
The computational investigation of the correlation between the achievable reaction yield and discharge energy for a plasma focus device (PFD) is presented. Radioisotope production in PFDs with applicable activities is highly dependent on establishing the related scaling law. Carbon target is bombarded by high energy deuterons and short-lived radioisotope of 13N is produced through 12C(d,n)13N in which the threshold energy is not very high. Both computed and measured ion energy spectra are used to estimate and optimize the scaling law. It is shown that the number of ions emitted from the pinch region for a device operating under optimized conditions is linearly proportional to the discharge energy of the PFD.
Detector and energy analyzer for energetic-hydrogen in beams and plasmas
Bastasz, R.J.; Hughes, R.C.; Wampler, W.R.
A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicon-dioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies. 4 figs.
Detector and energy analyzer for energetic-hydrogen in beams and plasmas
Bastasz, Robert J.; Hughes, Robert C.; Wampler, William R.
A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicondioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies.
Enhancement of the maximum proton energy by funnel-geometry target in laser-plasma interactions
NASA Astrophysics Data System (ADS)
Yang, Peng; Fan, Dapeng; Li, Yuxiao
Enhancement of the maximum proton energy using a funnel-geometry target is demonstrated through particle simulations of laser-plasma interactions. When an intense short-pulse laser illuminate a thin foil target, the foil electrons are pushed by the laser ponderomotive force, and then form an electron cloud at the target rear surface. The electron cloud generates a strong electrostatic field, which accelerates the protons to high energies. If there is a hole in the rear of target, the shape of the electron cloud and the distribution of the protons will be affected by the protuberant part of the hole. In this paper, a funnel-geometry target is proposed to improve the maximum proton energy. Using particle-in-cell 2-dimensional simulations, the transverse electric field generated by the side wall of four different holes are calculated, and protons inside holes are restricted to specific shapes by these field. In the funnel-geometry target, more protons are restricted near the center of the longitudinal accelerating electric field, thus protons experiencing longer accelerating time and distance in the sheath field compared with that in a traditional cylinder hole target. Accordingly, more and higher energy protons are produced from the funnel-geometry target. The maximum proton energy is improved by about 4 MeV compared with a traditional cylinder-shaped hole target. The funnel-geometry target serves as a new method to improve the maximum proton energy in laser-plasma interactions.