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Reaction of yttrium polonides with carbon dioxide
Abakumov, A.S.; Khokhlov, A.D.; Reznikova, N.F.
It has been proved that heating of yttrium and tantalum in carbon dioxide to 500 and 800/sup 0/C alters the gas phase composition, causing formation of carbon monoxide and reduction of oxygen content. A study of the thermal stability of yttrium polonides in carbon dioxide showed that yttrium sesqui- and monopolonides decompose at 400-430/sup 0/C. The temperature dependence of the vapor pressure of polonium obtained upon decomposition of the referred polonides has been determined in a carbon dioxide environment radiotensometrically. The enthalpy of the process calculated from this dependence is close to the enthalpy of vaporization of elemental polonium in vacuo. The mechanism of the reactions has been suggested.
Deposition of yttrium oxide thin films in supercritical carbon dioxide
Theodosia Gougousi; Zhiying Chen
A synthetic avenue for the formation of yttrium oxide thin films on Si native oxide surfaces is demonstrated by the reaction of Tris(2,2,6,6-tetramethyl-3,5-heptanedionato) yttrium(III) with inorganic (H2O2) and organic (tert-butyl and di-tert-amyl) peroxides in supercritical carbon dioxide. The reactions are carried out in a hot wall reactor at temperatures below 130Ā░C and pressures ranging from 13.10 to 22.75ĀMPa. Spectroscopic Ellipsometry
Thermal Decomposition of Lanthanide, Yttrium, and Scandium Oxalates and Carbonates
NASA Astrophysics Data System (ADS)
Sharov, Vyacheslav A.; Bezdenezhnykh, G. V.
Data concerning the thermal decomposition of lanthanide, yttrium, and scandium oxalates and carbonates are surveyed. The complexity of the process, the large number of stages involved, and the dependence of the composition of the intermediates in the thermal transformations on the experimental conditions is noted. Certain process characteristics have been discovered and it is concluded that the decomposition process depends on the ionic radius of the metal. The bibliography includes 83 references.
Yttrium silicate oxidation protective coating for SiC coated carbon\\/carbon composites
Jian-Feng Huang; He-Jun Li; Xie-Rong Zeng; Ke-Zhi Li
Four kinds of yttrium silicate oxidation protective coatings SiO2ĘY2O3, 1.5SiO2ĘY2O3, 1.5SiO2ĘY2O3\\/SiO2ĘY2O3 and 2SiO2ĘY2O3\\/1.5SiO2ĘY2O3\\/SiO2ĘY2O3 were prepared by plasma spray on the surface of SiC pre-coated carbon\\/carbon composites. The structures of the coatings were characterized by XRD, SEM and EDS analyses. It was shown that the gradied 2SiO2ĘY2O3\\/1.5SiO2ĘY2O3\\/SiO2ĘY2O3 multi-layer coating had better high-temperature oxidation resistance. It could protect carbon\\/carbon composites from oxidation
RBS and GAXRD contributions to yttrium implanted extra low carbon steel characterization
Caudron, E.; Buscail, H. [Equipe Locale Univ. Blaise Pascal Clermont-Fd II, Le Puy en Velay (France). Lab. Vellave d`Elaboration et d`Etude des Materiaux] [Equipe Locale Univ. Blaise Pascal Clermont-Fd II, Le Puy en Velay (France). Lab. Vellave d`Elaboration et d`Etude des Materiaux; Jacob, Y.P.; Stroosnijder, M.F. [European Commission, Ispra (Italy). Inst. for Advanced Materials] [European Commission, Ispra (Italy). Inst. for Advanced Materials
Extra low carbon steel samples were yttrium implanted using an ion implantation method. Composition and structural studies were carried out before and after yttrium implantations by several analytical and structural techniques (Rutherford backscattering spectrometry, reflection high energy electron diffraction, scanning electron microscopy, X-ray diffraction, and glancing angle X-ray diffraction) to characterize the yttrium implantation effect on extra low carbon steel. The aim of this article is to show the contributions of Rutherford back-scattering spectrometry (RBS) and glancing angle X-ray diffraction (GAXRD) to the determination of yttrium depth profiles in the samples. The results obtained by these techniques are compared to those of the other analyses performed in this work to show the existing correlation between composition and structural studies. Their results allow a better understanding of the effect of yttrium implantation in extra low carbon steel before studying their corrosion resistance at high temperature.
Solid solubilities of oxygen, carbon, and nitrogen in yttrium
O. N. Carlson; R. R. Lichtenberg; J. C. Warner
The solid solubilities were investigated and a partial diagram is ; proposed for the Y --YN system. The temperature dependence of the solubility of ; each solute in alpha yttrium was fitted empirically to Arrhenius-type ; equations, and the heats of solution for the coexisting oxide, carbide, or ; nitride phase were found to be 6.8 plus or minus 0.4,
The effect of chromium, carbon, and yttrium on the oxidation of nickel-base alloys in high temperature water
T. M. Angeliu
Since the surface film has been implicated in several models of intergranular stress corrosion cracking (IGSCC) of nickel-base alloys, this study was initiated to provide a foundation for the future study of a possible link between the nature of the surface film and IG crack susceptibility. The influence of chromium, carbon, and yttrium on the nature of the surface film
In situ high-temperature X-ray diffraction characterization of yttrium-implanted extra low-carbon steel
Caudron, E.; Buscail, H.; Perrier, S.
Yttrium-implanted and unimplanted extra low-carbon steel samples were analyzed at T = 700 C and under an oxygen partial pressure P{sub O2} = 0.041Pa for 24 h to show the yttrium implantation effect on extra low-carbon steel high-temperature corrosion resistance. Sample oxidation weight gains were studied by thermogravimetry, and structural analyses were performed using in situ high-temperature X-ray diffraction with the same experimental conditions. The aim of this paper is to show the initial nucleation stage of the main compounds induced by oxidation at high temperatures according to the initial sample treatment (yttrium-implanted or unimplanted). The results obtained by in situ high-temperature X-ray diffraction will be compared to those by thermogravimetry to show the existing correlation between weight gain curves and structural studies. Results allow one to understand the improved corrosion resistance of yttrium-implanted extra low-carbon steel at high temperatures.
High-performance carbon-nanotube-based complementary field-effect-transistors and integrated circuits with yttrium oxide
NASA Astrophysics Data System (ADS)
Liang, Shibo; Zhang, Zhiyong; Si, Jia; Zhong, Donglai; Peng, Lian-Mao
High-performance p-type carbon nanotube (CNT) transistors utilizing yttrium oxide as gate dielectric are presented by optimizing oxidization and annealing processes. Complementary metal-oxide-semiconductor (CMOS) field-effect-transistors (FETs) are then fabricated on CNTs, and the p- and n-type devices exhibit symmetrical high performances, especially with low threshold voltage near to zero. The corresponding CMOS CNT inverter is demonstrated to operate at an ultra-low supply voltage down to 0.2 V, while displaying sufficient voltage gain, high noise margin, and low power consumption. Yttrium oxide is proven to be a competitive gate dielectric for constructing high-performance CNT CMOS FETs and integrated circuits.
Synthesis of yttrium aluminum garnet (YAG) powder by homogeneous precipitation combined with supercritical carbon dioxide or ethanol fluid drying
Yang Ru; Qin Jie; Li Min; Liu Guoqiang
YAG precursors were synthesized by the urea method in aqueous solution using supercritical carbon dioxide and ethanol fluid drying technique, respectively. The composition of the precursors, the phase formation process and the properties of the calcined powders were investigated by means of XRD, IR, TG\\/DSC, BET, TEM and SEM. Compared with the classically prepared powders at room temperature in air,
Sorption of the Rare Earth Elements and Yttrium (REE-Y) in calcite: the mechanism of a new effective tool in identifying paleoearthquakes on carbonate faults
NASA Astrophysics Data System (ADS)
Moraetis, Daniel; Mouslopoulou, Vasiliki; Pratikakis, Alexandros
A new tool for identifying paleoearthquakes on carbonate faults has been successfully tested on two carbonate faults in southern Europe (the Magnola Fault in Italy and the Spili Fault in Greece): the Rare Earth Element and Yttrium (REE-Y) method (Manighetti et al., 2010; Mouslopoulou et al., 2011). The method is based on the property of the calcite in limestone scarps to absorb the REE and Y from the soil during its residence beneath the ground surface (e.g. before its exhumation due to earthquakes). Although the method is established, the details of the enrichment mechanism are poorly investigated. Here we use published data together with new information from pot-experiments to shed light on the sorption mechanism and the time effectiveness of the REE-Y method. Data from the Magnola and Spili faults show that the average chemical enrichment is ~45%, in REE-Y while the denudation rate of the enriched zones is ~1% higher every 400 years due to exposure of the fault scarp in weathering. They also show that the chemical enrichment is significant even for short periods of residence time (e.g., ~100 years). To better understand the enrichment mechanism, we performed a series of pot experiments, where carbonate tiles extracted from the Spili Fault were buried into soil collected from the hanging-wall of the same fault. We irrigated the pots with artificial rain that equals 5 years of rainfall in Crete and at temperatures of 15oC and 25oC. Following, we performed sorption isotherm, kinetic and pH-edge tests for the europium (Eu), the cerium (Ce) and the ytterbium (Yt) that occur in the calcite minerals. The processes of adsorption and precipitation in the batch experiments are simulated by the Mineql software. The pot experiments indicate incorporation of the REE and Y into the surface of the carbonate tile which is in contact with the soil. The pH of the leached solution during the rain application range from 7.6 to 8.3. Nutrient release like Ca is higher in the leached solution at lower temperature (15oC) probably due to higher calcite solubility (higher dissolved CO2(g) content) and to less adsorption capability of the soil in elevated temperatures. The isotherm sorption modeling showed that REE-(CO3)2 precipitation is the dominant mechanism in the incorporation of REE into calcite, while the kinetic tests showed instant REE sorption (within few hours). Our experiments show that pH>7.5 and temperatures ~25░ C favor REE-Y sorption on calcite surface. Hence, due to the REE-Y fast interaction with carbonate scarp face and the low denudation rate due to later weathering, the REE-Y method is considered a reliable method for tracing paleoearthquakes along carbonate fault scarps when the scarp is in contact with soil at temperate climates. The resolution of identifying frequent paleoearthquakes with low residence time in contact with soil is also considered high. References Mouslopoulou, V., Moraetis, D., Fassoulas, C., 2011. Earth Planet. Sci. Lett. 309, 45-55. Manighetti, I., Boucher, E., Chauvel, A., Schlagenhauf, A., Benedetti, L., 2010. Terra Nova 22, 477-482.
NSDL National Science Digital Library
Maryland Virtual High School
Life on earth is based on carbon. Living things acquire carbon from their environment - from air, water, soil, and rock and from other living things - through processes such as photosynthesis, respiration and decomposition. The carbon cycle model is a representation of the movement of carbon from sources to sinks through chemical and physical transfers. The carbon cycle activity allows students to see the effect of fossil fuel burning on the carbon cycle.
NASA Technical Reports Server (NTRS)
Ransone, Philip O. (Inventor)
A lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials, such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.
Carbon Smackdown: Carbon Capture
Jeffrey Long
In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air
Carbon Smackdown: Carbon Capture
Jeffrey Long
In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air
Carbon-carbon piston development
NASA Technical Reports Server (NTRS)
Gorton, Mark P.
A new piston concept, made of carbon-carbon refractory-composite material, has been developed that overcomes a number of the shortcomings of aluminum pistons. Carbon-carbon material, developed in the early 1960's, is lighter in weight than aluminum, has higher strength and stiffness than aluminum and maintains these properties at temperatures over 2500 F. In addition, carbon-carbon material has a low coefficient of thermal expansion and excellent resistance to thermal shock. An effort, called the Advanced Carbon-Carbon Piston Program was started in 1986 to develop and test carbon-carbon pistons for use in spark ignition engines. The carbon-carbon pistons were designed to be replacements for existing aluminum pistons, using standard piston pin assemblies and using standard rings. Carbon-carbon pistons can potentially enable engines to be more reliable, more efficient and have greater power output. By utilizing the unique characteristics of carbon-carbon material a piston can: (1) have greater resistance to structural damage caused by overheating, lean air-fuel mixture conditions and detonation; (2) be designed to be lighter than an aluminum piston thus, reducing the reciprocating mass of an engine, and (3) be operated in a higher combustion temperature environment without failure.
Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...
NASA Technical Reports Server (NTRS)
Frant, M. S.
Inorganic carbon is removed from samples to be analyzed for "total organic carbon". In automated water analysis systems, semipermeable membrane separates two sample streams, one treated with acid, other with base. Carbonate and bicarbonated ions are converted to dissolved CO2 by acid; reverse process occurs in basic stream. Only CO2 is passed by membrane, from acid treated stream to base treated stream. Acidic stream emerges free of all inorganic carbon.
NSDL National Science Digital Library
In this inquiry-based lesson, learners measure the biomass of trees, calculate the carbon stored by the trees, and use this information to create recommendations about using trees for carbon sequestration. This activity encourages learners to think critically about managing forests for carbon sequestration.
NSDL National Science Digital Library
Carbon Footprint Ltd
This website has interactive tools to calculate your carbon footprint, which is a way to measure how much carbon dioxide and other greenhouse gases are produced by your activities. This site also contains specific recommendations for reducing and off-setting your carbon footprint, as well as links to news and information about global warming.
Carbon-Carbon Piston Architectures
NASA Technical Reports Server (NTRS)
Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)
An improved structure for carbon-carbon composite piston architectures consists of replacing the knitted fiber, three-dimensional piston preform architecture described in U.S. Pat. No. 4.909,133 (Taylor et al.) with a two-dimensional lay-up or molding of carbon fiber fabric or tape. Initially. the carbon fabric or tape layers are prepregged with carbonaceous organic resins and/or pitches and are laid up or molded about a mandrel. to form a carbon-fiber reinforced organic-matrix composite part shaped like a "U" channel, a "T"-bar. or a combination of the two. The molded carbon-fiber reinforced organic-matrix composite part is then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. At this point, cylindrical piston blanks are cored from the "U" channel, "T"-bar, or combination part. These blanks are then densified by reimpregnation with resins or pitches which are subsequently carbonized. Densification is also be accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston billets are machined to final piston dimensions; coated with oxidation sealants; and/or coated with a catalyst. When compared to conventional steel or aluminum-alloy pistons, the use of carbon-carbon composite pistons reduces the overall weight of the engine; allows for operation at higher temperatures without a loss of strength; allows for quieter operation; reduces the heat loss; and reduces the level of hydrocarbon emissions.
Carbon-Carbon Piston Architectures
NASA Technical Reports Server (NTRS)
Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)
An improved structure for carbon-carbon composite piston architectures is disclosed. The improvement consists of replacing the knitted fiber, three-dimensional piston preform architecture described in U.S. Pat.No. 4,909,133 (Taylor et al.) with a two-dimensional lay-up or molding of carbon fiber fabric or tape. Initially, the carbon fabric of tape layers are prepregged with carbonaceous organic resins and/or pitches and are laid up or molded about a mandrel, to form a carbon-fiber reinforced organic-matrix composite part shaped like a "U" channel, a "T"-bar, or a combination of the two. The molded carbon-fiber reinforced organic-matrix composite part is then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. At this point, cylindrical piston blanks are cored from the "U"-channel, "T"-bar, or combination part. These blanks are then densified by reimpregnation with resins or pitches which are subsequently carbonized. Densification is also accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston billets are machined to final piston dimensions; coated with oxidation sealants; and/or coated with a catalyst. When compared to conventional steel or aluminum alloy pistons, the use of carbon-carbon composite pistons reduces the overall weight of the engine; allows for operation at higher temperatures without a loss of strength; allows for quieter operation; reduces the heat loss; and reduces the level of hydrocarbon emissions.
Developments in carbon materials
NASA Technical Reports Server (NTRS)
Burchell, Timothy D.
The following carbon-based materials are reviewed and their applications discussed: fullerenes; graphite (synthetic and manufactured); activated carbon fibers; and carbon-carbon composites. Carbon R&D activities at ORNL are emphasized.
NSDL National Science Digital Library
In this experiment, learners will investigate the release of carbon-containing gas from living and nonliving sources. Learners scratch the surface of a limestone rock and observe what happens when they place a few drops of vinegar on the scratched area. Next, learners observe what happens when they release carbon dioxide from a balloon into a beaker with Bromothymol Blue. Learners are encouraged to consider how the results of this experiment would change if they added an aquatic plant to the beaker and also design a method for demonstrating how plants give off carbon dioxide.
Infiltrated carbon foam composites
NASA Technical Reports Server (NTRS)
Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)
An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.
NSDL National Science Digital Library
This interactive animation focuses on the carbon cycle and includes embedded videos and captioned images to provide greater clarification and detail of the cycle than would be available by a single static visual alone.
Morphological Changes of Human Dentin after Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) and Carbon Dioxide (CO2) Laser Irradiation and Acid-etch Technique: An Scanning Electron Microscopic (SEM) Evaluation
Shahabi, Sima; Chiniforush, Nasim; Juybanpoor, Nasrin
Introduction: The aim of this study was to investigate the morphological changes of human dentin after Erbium-Doped Yttrium Aluminum Garnet (Er:YAG), Carbon Dioxide(CO2) laser-irradiation and acid-etching by means of scanning electron microscopic (SEM) Methods: 9 extracted human third molars were used in this study. The teeth were divided in three groups: first group, CO2 laser with power of 1.5 w and frequency of 80 Hz; second group, Er:YAG laser with output power of 1.5 W frequency of 10 Hz, very short pulse with water and air spray was applied; and third group, samples were prepared by acid-etching 37% for 15 sec and rinsed with air-water spray for 20 sec. Then, the samples were prepared for SEM examination. Results: Melting and cracks can be observed in CO2 laser but in Er:YAG laser cleanedablated surfaces and exposed dentinal tubules, without smear layer was seen. Conclusion: It can be concluded that Er:YAG laser can be an alternative technique for surface treatment and can be considered as safe as the conventional methods. But CO2 laser has some thermal side effects which make this device unsuitable for this purpose. PMID:25606306
Manual of carbonate sedimentology
Reijers, T.J.; Hsu, K.S.
This manual, organised along encycolopaedic/lexicographic lines, summarizes information on the properties and characteristics of carbonates and their environments. Part 1 deals with the elements of carbonates; Part 2 with environments, settings, and carbonate bodies; Part 3 with carbonate diagenesis, and Part 4 with carbonate reservoirs. Contents include: Elements of carbonates; Carbonate Environments, Settings and Bodies; Carbonate diagenesis; Carbonate reservoirs; Alphabetical Indices; English, Dutch, German, Spanish, French Computer Compatible Codes; Commonly Used (Informal) abbreviations.
NSDL National Science Digital Library
NASA: Challenger Center
With this carbon/temperature interactive model, students investigate the role of atmospheric carbon in the greenhouse effect using a relationship between atmospheric carbon dioxide and global temperature.
Delnick, F.M.
Carbon supercapacitors are represented as distributed RC networks with transmission line equivalent circuits. At low charge/discharge rates and low frequencies these networks approximate a simple series R{sub ESR}C circuit. The energy efficiency of the supercapacitor is limited by the voltage drop across the ESR. The pore structure of the carbon electrode defines the electrochemically active surface area which in turn establishes the volume specific capacitance of the carbon material. To date, the highest volume specific capacitance reported for a supercapacitor electrode is 220F/cm{sup 3} in aqueous H{sub 2}SO{sub 4} (10) and {approximately}60 F/cm{sup 3} in nonaqueous electrolyte (8).
NSDL National Science Digital Library
Jonathan Corum
This is a polar map of permafrost extent in the Northern Hemisphere. A sidebar explains how permafrost, as it forms and later thaws, serves as both a sink and source for carbon to the atmosphere. Related multimedia is a slideshow of permafrost scientists from U. of Alaska, Fairbanks, collecting permafrost data in the field.
NSDL National Science Digital Library
Arie Melamed-Katz (None; )
Bubbles are an indicator of a chemical reaction. An indicator is an object, material, or organism that tells you if a specific substance is present. In the sugar test, carbon dioxide gas release is an indicator that yeast is using sugar to grow. The more gas produced, the more sugar a specific substance contains.
Molecular Structure of Carbonate ion
NSDL National Science Digital Library
Carbonates were studied extensively by geologists. Common carbonate-containing geologic materials are barium calcium carbonate, lead carbonate, and strontium carbonate. Carbonate is the salt of carbonic acid. Many counter ions are possible, including calcium carbonate and barium carbonate. Calcium carbonate is a brittle white rock, used in many buildings. Lithium carbonate is used to treat manic phases for bipolar disorder/manic depression. Carbonic acid is found in carbonated beverages, giving them a tart flavor.
Carbon takeoff [carbon fiber composites
E. Guizzo
This paper describes the novel design of Boeing's new 787 Dreamliner, which showcases a fuselage and wings made almost entirely of carbon-fiber composites. The composite wing is lighter and more resistant to fatigue and corrosion than aluminum wings, and will help save fuel and lower maintenance costs. More than just another all-new plane, the 787 represents an evolutionary transition for
The report is a study of the development of funds to invest in the purchase of carbon credits. It takes a look at the growing market for carbon credits, the rise of carbon investment funds, and the current state of carbon investing. Topics covered in the report include: Overview of climate change, greenhouse gases, and the Kyoto Protocols. Analysis of the alternatives for reducing carbon emissions including nitrous oxide reduction, coal mine methane capture and carbon capture and storage; Discussion of the different types of carbon credits; Discussion of the basics of carbon trading; Evaluation of the current status of carbon investing; and Profiles of 37 major carbon investment funds worldwide.
Carbon-carbon piston development. Final report
Gorton, M.P.
A new piston concept, made of carbon-carbon refractory-composite material, has been developed that overcomes a number of the shortcomings of aluminum pistons. Carbon-carbon material, developed in the early 1960's, is lighter in weight than aluminum, has higher strength and stiffness than aluminum and maintains these properties at temperatures over 2500 F. In addition, carbon-carbon material has a low coefficient of thermal expansion and excellent resistance to thermal shock. An effort, called the Advanced Carbon-Carbon Piston Program was started in 1986 to develop and test carbon-carbon pistons for use in spark ignition engines. The carbon-carbon pistons were designed to be replacements for existing aluminum pistons, using standard piston pin assemblies and using standard rings. Carbon-carbon pistons can potentially enable engines to be more reliable, more efficient and have greater power output. By utilizing the unique characteristics of carbon-carbon material a piston can: (1) have greater resistance to structural damage caused by overheating, lean air-fuel mixture conditions and detonation; (2) be designed to be lighter than an aluminum piston thus, reducing the reciprocating mass of an engine, and (3) be operated in a higher combustion temperature environment without failure.
NSDL National Science Digital Library
Since the Industrial Revolution, atmospheric carbon dioxide concentration has risen from ~280ppm (parts per million by volume) to ~390ppm in 2010. The rate of increase for the last decade (2001-2010) has been 2.04ppm/yr, more than double the rate for the 1960's. Most scientists agree that human actions are the primary cause of the increase, the rise in Earth's average temperature since the mid-1900's and recent climate change. In this problem-based learning activity, learners develop a carbon mitigation strategy to address climate change issues. This module was developed to be used in the Earth System Science Education Alliance (ESSEA) courses for middle and high school teachers and is also available to teachers to adapt for general classroom use.
Freemont, A J
Controlling hyperphosphatemia in patients with chronic renal failure on renal dialysis is a major problem. None of the available calcium- or aluminum-based phosphate binders match the requirements for an ideal agent, each having its own limitations. The introduction of sevelamer hydrochloride represented a step change in management. Lanthanum carbonate is an alternative nonaluminium, noncalcium phosphate binder. Taken with food, it is well tolerated. It is poorly absorbed and does not require functioning kidneys to be removed from the body. There is no evidence from current studies that it accumulates to biologically significant levels in tissues, but despite the large numbers of patients included in clinical trials, experience with long-term dosing is limited and, as with every new drug used in this type of clinical setting, patients should be carefully monitored as experience with the drug increases. Lanthanum carbonate binds phosphate effectively across the physiological pH range of the upper gastrointestinal tract, and has no detrimental effect on calcium, vitamin D or parathyroid hormone metabolism. From the extensive trial data it seems that lanthanum carbonate is an effective and practical phosphate binder. Lanthanum carbonate and sevelamer are two new oral phosphate binding agents that with others currently in preclinical trials, such as stabilized polynuclear iron idroxide, could well represent a significant breakthrough in the management of hyperphosphatemia in patients with chronic renal failure in whom dietary phosphate restriction and cheaper oral phosphate binding agents prove unsatisfactory. Comparative trials and enhanced clinical experience are needed before the exact place of these competing and complementary therapies can be properly identified in patient management. PMID:17285149
NSDL National Science Digital Library
Austen Saltz
In this activity, learners investigate carbon sequestration by creating a carbonated beverage out of apple juice and dry ice. This experiment illustrates how carbon dioxide can be stored in a substance. Learners compare and contrast the results to determine if liquid carbonation is an effective method for carbon sequestration. Safety note: this activity involves dry ice; please follow recommended guidelines.
The nature of carbon in forests is discussed from the perspective of carbon trading. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Carbon turnover in forests is discussed as it relates to carbon sequestration. Scient...
Carbon Cycle: Where Is This Crucial Carbon?
NSDL National Science Digital Library
This demonstration aims to teach students about the nature of carbon, the different types of compounds it exists in (e.g. charcoal, glucose, carbon dioxide), the biochemical reactions it takes part in (photosynthesis and respiration), the range of processes that carbon and carbon compounds are involved in on Earth, and how these link together to form the carbon cycle. Students will be reminded that carbon is the fundamental building block of life (the element that life is based on). They will discover that carbon is contained in everything from fossil fuels to DNA and is cycled and re-cycled through the carbon cycle. Students will also understand that both animals and plants need carbon although they obtain it in different ways. This site has teacher notes and directions, suggested questions with answers, a list of required materials, and a glossary.
Photophysics of carbon nanotubes
Samsonidze, Georgii G
This thesis reviews the recent advances made in optical studies of single-wall carbon nanotubes. Studying the electronic and vibrational properties of carbon nanotubes, we find that carbon nanotubes less than 1 nm in ...
NSDL National Science Digital Library
This narrated slide presentation shows the carbon cycle, looking at various parts of this biogeochemical sequence by examining carbon reservoirs and how carbon is exchanged among them and the atmosphere.
CALIFORNIA ENERGY COMMISSION CARBON SEQUESTRATION THROUGH CHANGES IN LAND USE IN WASHINGTON. Carbon Sequestration Through Changes in Land Use in Washington: Costs and Opportunities. California for Terrestrial Carbon Sequestration in Oregon. Report to Winrock International. #12;ii #12;iii Preface
NASA Technical Reports Server (NTRS)
Williams, C. F.; Huebscher, R. G.
Passed exhaled air through electrochemical cell containing alkali metal carbonate aqueous solution, and utilizes platinized electrodes causing reaction of oxygen at cathode with water in electrolyte, producing hydroxyl ions which react with carbon dioxide to form carbonate ions.
Carbon Code Requirements for voluntary carbon sequestration projects
Woodland Carbon Code Requirements for voluntary carbon sequestration projects « Version 1.2 July trademark 10 3. Carbon sequestration 11 3.1 Units of carbon calculation 11 3.2 Carbon baseline 11 3.3 Carbon leakage 12 3.4 Project carbon sequestration 12 3.5 Net carbon sequestration 13 4. Environmental quality 14
Carbon-carbon grid for ion engines
NASA Technical Reports Server (NTRS)
Garner, Charles E. (inventor)
A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.
Carbon-carbon grid for ion engines
NASA Technical Reports Server (NTRS)
Garner, Charles E. (inventor)
A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.
From carbon nanotubes to carbon atomic chains
NASA Astrophysics Data System (ADS)
Casillas GarcĒa, Gilberto; Zhang, Weijia; Josķ-Yacamßn, Miguel
Carbyne is a linear allotrope of carbon. It is formed by a linear arrangement of carbon atoms with sp-hybridization. We present a reliable and reproducible experiment to obtain these carbon atomic chains using few-layer-graphene (FLG) sheets and a HRTEM. First the FLG sheets were synthesized from worm-like exfoliated graphite and then drop-casted on a lacey-carbon copper grid. Once in the TEM, two holes are opened near each other in a FLG sheet by focusing the electron beam into a small spot. Due to the radiation, the carbon atoms rearrange themselves between the two holes and form carbon fibers. The beam is concentrated on the carbon fibers in order excite the atoms and induce a tension until multi wall carbon nanotube (MWCNT) is formed. As the radiation continues the MWCNT breaks down until there is only a single wall carbon nanotube (SWCNT). Then, when the SWCNT breaks, an atomic carbon chain is formed, lasts for several seconds under the radiation and finally breaks. This demonstrates the stability of this carbon structure.
NASA Technical Reports Server (NTRS)
Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)
A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.
Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun
A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.
NSDL National Science Digital Library
American Museum of Natural History
In this experiment, students will observe a natural process that removes carbon dioxide (CO2) from Earth's atmosphere. This process is a part of the carbon cycle and results in temperature suitable for life. Students will learn that the carbon cycle is a fundamental Earth process. Throughout Earth's history, the balance of carbon has kept the atmosphere's carbon dioxide (CO2) and Earth's temperature within relatively narrow ranges.
Properties Of Carbon/Carbon and Carbon/Phenolic Composites
NASA Technical Reports Server (NTRS)
Mathis, John R.; Canfield, A. R.
Report presents data on physical properties of carbon-fiber-reinforced carbon-matrix and phenolic-matrix composite materials. Based on tests conducted on panels, cylinders, blocks, and formed parts. Data used by designers to analyze thermal-response and stress levels and develop structural systems ensuring high reliability at minimum weight.
Bhattacharyya, A.; Friedman, G.M.
This book offers help in evaluating potential sites for oil and gas accumulations. Pointing the way to discovery of hydrocarbons in carbonate reservoirs, this volume discusses modern carbonate depositional environments in different geomorphic settings. It compiles papers by scientists whose observations have revolutionized current thinking on facies relationships in ancient carbonate rock. Contents include: Selected carbonate regions --The Algal Sediments on Androa Island in the Bahamas, Sedimentary Facies, Interaction of Genetic Processes in Holocene Reefs off North Eleuthera Island in the Bahamas, Recent Anhydrite, Holocene Shallow-Water Carbonate and Evaporite Sediments of Khor al Bazam; Carbonate production--On the Origin of Aragonite in the Dead Sea, Carbonate Production by Coral Reefs; Cold-water carbonates--Contributions on the Geology of the Northwestern Peninsula of Iceland, Evaluation of Cold-Water Carbonates as a Possible Paleoclimatic Indicator.
Carbon fuel cells with carbon corrosion suppression
Cooper, John F. (Oakland, CA)
An electrochemical cell apparatus that can operate as either a fuel cell or a battery includes a cathode compartment, an anode compartment operatively connected to the cathode compartment, and a carbon fuel cell section connected to the anode compartment and the cathode compartment. An effusion plate is operatively positioned adjacent the anode compartment or the cathode compartment. The effusion plate allows passage of carbon dioxide. Carbon dioxide exhaust channels are operatively positioned in the electrochemical cell to direct the carbon dioxide from the electrochemical cell.
Preparation of activated carbons with mesopores by use of organometallics
Yamada, Y.; Yoshizawa, N.; Furuta, T.; Shiraishi, M. [National Inst. for Resources and Environment, Ibaraki (Japan)] [and others
Mesopore carbons were prepared by steam activation of pitch or coal with metal chelate complexes. Yttrium acetylacetonate dispersed in a coal tar pitch enhanced the mesopore ratio in the activated carbon obtained. When Mike, Taiheiyo or Morwell coal was used in the place of the pitch, titanium oxide acetylacetonate was effective for the formation of the mesopore carbons. The specific surface areas and mesopore ratios were evaluated by measuring the nitrogen adsorption isotherms. In addition, the crystal size and the distribution of metals on the carbon were observed by transmission electron microscope and the formation mechanism of mesopores was estimated from these results.
Cohen, Marvin Lou (Berkeley, CA); Crespi, Vincent Henry (Darien, IL); Louie, Steven Gwon Sheng (Berkeley, CA); Zettl, Alexander Karlwalter (Kensington, CA)
Novel metallic forms of planar carbon are described, as well as methods of designing and making them. Nonhexagonal arrangements of carbon are introduced into a graphite carbon network essentially without destroying the planar structure. Specifically a form of carbon comprising primarily pentagons and heptagons, and having a large density of states at the Fermi level is described. Other arrangements of pentagons and heptagons that include some hexagons, and structures incorporating squares and octagons are additionally disclosed. Reducing the bond angle symmetry associated with a hexagonal arrangement of carbons increases the likelihood that the carbon material will have a metallic electron structure.
NSDL National Science Digital Library
This Earth Observatory site contains detailed information on the carbon cycle of the Earth. It provides an explanation of the role of carbon in the geologic carbon cycle followed by a discussion of carbon in the life process, including photosynthesis and respiration. Carbon sinks on land and in the ocean are covered next, followed by the human role in the cycle. Lastly, the activity of the National Aeronautics and Space Administration, (NASA), and that of the National Oceanic and Atmospheric Administration, (NOAA) in the exploration of the connection of the carbon cycle to weather and climate is covered.
Method of making carbon-carbon composites
Engle, Glen B. (16716 Martincoit Rd., Poway, CA 92064)
A process for making a carbon-carbon composite having a combination of high crystallinity, high strength, high modulus and high thermal and electrical conductivity. High-modulus/high-strength mesophase derived carbon fibers are woven into a suitable cloth. Layers of this easily graphitizable woven cloth are covered with petroleum or coal tar pitch and pressed at a temperature a few degrees above the softening point of the pitch to form a green laminated composite. The green composite is restrained in a suitable fixture and heated slowly to carbonize the pitch binder. The carbonized composite is then impregnated several times with pitch by covering the composite with hot pitch under pressure. The composites are given a heat treatment between each impregnation step to crack up the infiltrated carbon and allow additional pitch to enter the microstructure during the next impregnation cycle. The impregnated composites are then given a final heat treatment in the range 2500.degree. to 3000.degree. C. to fully graphitize the fibers and the matrix carbon. The composites are then infiltrated with pyrolytic carbon by chemical vapor deposition in the range 1000.degree. to 1300.degree. C. at a reduced pressure for approximately one hundred and fifty (150) hours.
Carbon cycle: Hoard of fjord carbon
NASA Astrophysics Data System (ADS)
Keil, Richard
Fjords account for less than 0.1% of the surface of Earth's oceans. A global assessment finds that organic carbon is buried in fjords five times faster than other marine systems, accounting for 11% of global marine organic carbon burial.
Carbon nanotube nanoelectrode arrays
Ren, Zhifeng (Newton, MA); Lin, Yuehe (Richland, WA); Yantasee, Wassana (Richland, WA); Liu, Guodong (Fargo, ND); Lu, Fang (Burlingame, CA); Tu, Yi (Camarillo, CA)
The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.
Sedjo, R.A. (Resources for the Future, Washington, DC (USA))
The author discusses the global carbon cycle and cites the results of several recently completed research projects, that seem to indicate that the temperate zone forests are a sink for carbon rather than a source, as was previously believed.
Shaw, Bryan W.; Garcia, Monica L.
Protect yourself and your family from the deadly effects of carbon monoxide--a colorless, odorless poisonous gas. This publication describes the warning signs of carbon monoxide exposure and includes a home safety checklist....
Shaw, Bryan W.; Garcia, Monica L.
Protect yourself and your family from the deadly effects of carbon monoxide--a colorless, odorless poisonous gas. This publication describes the warning signs of carbon monoxide exposure and includes a home safety checklist....
Interstellar carbon in meteorites
NASA Technical Reports Server (NTRS)
Swart, P. K.; Grady, M. M.; Pillinger, C. T.; Lewis, R. S.; Anders, E.
The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to +1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This 'heavy' carbon is associated with neon-22 and with anomalous krypton and xenon showing the signature of the s-process (neutron capture on a slow time scale). It apparently represents interstellar grains ejected from late-type stars. A second anomalous xenon component ('CCFXe') is associated with a distinctive, light carbon (depleted in carbon-13 by 38 per mil), which, however, falls within the terrestrial range and hence may be of either local or exotic origin.
Carbon Based Nanotechnology: Review
NASA Technical Reports Server (NTRS)
Srivastava, Deepak; Saini, Subhash (Technical Monitor)
This presentation reviews publicly available information related to carbon based nanotechnology. Topics covered include nanomechanics, carbon based electronics, nanodevice/materials applications, nanotube motors, nano-lithography and H2O storage in nanotubes.
Carbon/Carbon Pistons for Internal Combustion Engines
NASA Technical Reports Server (NTRS)
Taylor, A. H.
Carbon/carbon piston performs same function as aluminum pistons in reciprocating internal combustion engines while reducing weight and increasing mechanical and thermal efficiencies of engine. Carbon/carbon piston concept features low piston-to-cylinder wall clearance - so low piston rings and skirts unnecessary. Advantages possible by negligible coefficient of thermal expansion of carbon/carbon.
R. A. Houghton
The global carbon cycle refers to the exchanges of carbon within and between four major reservoirs: the atmosphere, the oceans, land, and fossil fuels. Carbon may be transferred from one reservoir to another in seconds (e.g., the fixation of atmospheric CO2 into sugar through photosynthesis) or over millennia (e.g., the accumulation of fossil carbon (coal, oil, gas) through deposition and
Understanding the Carbon Cycle
NSDL National Science Digital Library
In this unit, students use Internet resources, slide presentations, and modeling to explain how understanding the carbon cycle helps scientists understand and prepare for global climate change, what might happen if sources of carbon produced more than sinks could remove, and what might happen if sinks absorbed more than sources produced. They should understand how the carbon cycle affects various life forms and the role that carbon plays in their lives. Procedures, a glossary, assessments, and scoring rubrics are provided.
Graphitization in Carbon MEMS and Carbon NEMS
NASA Astrophysics Data System (ADS)
Sharma, Swati
Carbon MEMS (CMEMS) and Carbon NEMS (CNEMS) are an emerging class of miniaturized devices. Due to the numerous advantages such as scalable manufacturing processes, inexpensive and readily available precursor polymer materials, tunable surface properties and biocompatibility, carbon has become a preferred material for a wide variety of future sensing applications. Single suspended carbon nanowires (CNWs) integrated on CMEMS structures fabricated by electrospinning of SU8 photoresist on photolithographially patterned SU8 followed by pyrolysis are utilized for understanding the graphitization process in micro and nano carbon materials. These monolithic CNW-CMEMS structures enable the fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core---shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We explore various tunable fabrication and pyrolysis parameters to improve graphitization in the resulting CNWs. We also suggest gas-sensing application of the thus fabricated single suspended CNW-CMEMS devices by using the CNW as a nano-hotplate for local chemical vapor deposition. In this thesis we also report on results from an optimization study of SU8 photoresist derived carbon electrodes. These electrodes were applied to the simultaneous detection of traces of Cd(II) and Pb(II) through anodic stripping voltammetry and detection limits as low as 0.7 and 0.8 microgL-1 were achieved. To further improve upon the electrochemical behavior of the carbon electrodes we elucidate a modified pyrolysis technique featuring an ultra-fast temperature ramp for obtaining bubbled porous carbon from lithographically patterned SU8. We conclude this dissertation by suggesting the possible future works on enhancing graphitization as well as on electrochemical applications
NETL's Carbon Sequestration Program is helping to develop technologies to capture, purify, and store carbon dioxide (CO2) in order to reduce greenhouse gas emissions without adversely influencing energy use or hindering economic growth. Carbon sequestration technologies capture and store CO2 that would otherwise reside in the atmosphere for long periods of time.
NSDL National Science Digital Library
This page is an introduction to the Molten Carbonate fuel cell. It uses flash animation to explain in greater detail what the Molten Carbonate fuel cell consists of and how it works. The website has an introductory animation which is followed by more in depth description of the molten carbonate fuel cell works.
NSDL National Science Digital Library
Elizabeth Sulzman
This module covers the basics of the carbon cycle and research efforts that aim to integrate ecology and the earth sciences, and describes new methodologies being developed to explore the carbon cycle. The module is divided into the following sections: Overview, Exchanges between Reservoirs, Feedbacks in the Carbon Cycle, Implications for Global Climate, Questions and Discussion Topics, Glossary, and Suggested Reading.
NSDL National Science Digital Library
The mission of NanoLab, Inc. is to utilize nanoscale science and engineering to create high value products from carbon nanotubes, aligned carbon nanotube arrays, and other nanomaterials. This website provides an image gallery of: carbon nanotubes, nanoparticles, nanowire, as well as nanotube fillings, coatings, and arrays.
NETL's Carbon Sequestration Program is helping to develop technologies to capture, purify, and store carbon dioxide (CO2) in order to reduce greenhouse gas emissions without adversely influencing energy use or hindering economic growth. Carbon sequestration technologies capture and store CO2 that would otherwise reside in the atmosphere for long periods of time.
Templated nanoscale porous carbons
NASA Astrophysics Data System (ADS)
Xia, Yongde; Yang, Zhuxian; Mokaya, Robert
This manuscript reviews key developments in the important and rapidly expanding area of templated porous carbons. The porosity covered ranges from microporous to mesoporous and macroporous carbons. Two modes of templating, using so-called hard and soft templates, are covered. In particular, for hard templating, zeolite templating generates microporous carbons, mesoporous silicates yield mesoporous carbons, while colloidal particles are replicated to large mesoporous and macroporous carbons. Soft-templating, a more recent phenomenon, mainly generates mesoporous carbons. The full range of pore sizes can therefore now be accessed using hard and soft templates to generate highly ordered nanoscale carbons with well-defined and optimised textural properties. The research area has seen rapid and important developments over the last few years, and this review aims to present the more significant advances.
Templated nanoscale porous carbons.
Xia, Yongde; Yang, Zhuxian; Mokaya, Robert
This manuscript reviews key developments in the important and rapidly expanding area of templated porous carbons. The porosity covered ranges from microporous to mesoporous and macroporous carbons. Two modes of templating, using so-called hard and soft templates, are covered. In particular, for hard templating, zeolite templating generates microporous carbons, mesoporous silicates yield mesoporous carbons, while colloidal particles are replicated to large mesoporous and macroporous carbons. Soft-templating, a more recent phenomenon, mainly generates mesoporous carbons. The full range of pore sizes can therefore now be accessed using hard and soft templates to generate highly ordered nanoscale carbons with well-defined and optimised textural properties. The research area has seen rapid and important developments over the last few years, and this review aims to present the more significant advances. PMID:20648305
Carbon dioxide sequestration by direct mineral carbonation with carbonic acid
O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.
The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.
Carbon isotopes in mollusk shell carbonates
Ted A. McConnaughey; David Paul Gillikin
Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell\\u000a formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod\\u000a shell carbonates. Land snails construct their shells mainly from respired CO2, and shell ?13C reflects the local mix of C3 and C4 plants
Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)
The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).
Carbon Sequestration via Mineral Carbonation: Overview and Assessment
1 Carbon Sequestration via Mineral Carbonation: Overview and Assessment 14 March 2002 Howard Herzog overview and assessment of carbon sequestration by mineral carbonation (referred to as "mineral sequestration R&D. The first is that carbonates have a lower energy state than CO2. Therefore, at least
Pyrolytic carbon electrodes Lithographically Defined Porous Carbon Electrodes**
New Mexico, University of
Pyrolytic carbon electrodes Lithographically Defined Porous Carbon Electrodes** D. Bruce Burckel Polsky* The special nature of the C└C bond can lead to various polymorphic forms of carbon such as graphite, glassy-carbon, fullerenes (such as buckyballs), carbon nanotubes, and diamond. Electrodes made
Molten carbonate fuel cell separator
NASA Astrophysics Data System (ADS)
Nickols, R. C.
In a stacked array of molten carbonate fuel cells, a fuel cell separator is positioned between adjacent fuel cells to provide isolation as well as a conductive path therebetween. The center portion of the fuel cell separator includes a generally rectangular, flat, electrical conductor. Around the periphery of the flat portion of the separator are positioned a plurality of elongated resilient flanges which form a gas tight seal around the edges of the fuel cell. With one elongated flange resiliently engaging a respective edge of the center portion of the separator, the sealing flanges, which are preferably comprised of a noncorrosive material such as an alloy of yttrium, iron, aluminum or chromium, form a tight fitting wet seal for confining the corrosive elements of the fuel cell therein. This arrangement permits a good conductive material which may be highly subject to corrosion and dissolution to be used in combination with a corrosion resistant material in the fuel cell separator of a molten carbonate fuel cell for improved fuel cell conductivity and a gas tight wet seal.
Dai, Sheng; Wang, Xiqing
The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.
Dai, Sheng (Knoxville, TN); Wang, Xiqing (Oak Ridge, TN)
The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.
Carbon capture and sequestration (CCS) is the long-term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. This includes a range of approaches including soil carbon sequestration (e.g., through no-till farming), terrestrial biomass sequestration (e.g., through planting forests), direct ocean injection of COŌ either onto the deep seafloor or into the intermediate depths, injection into
NSDL National Science Digital Library
NASA Goddard Space Flight Center
Students explore the carbon cycle and the relationship between atmospheric carbon dioxide concentrations and temperature. Students create and compare graphs of carbon dioxide and temperature data from one local (Mauna Loa, Hawaii) meteorological station and one NASA global data set. These graphs, as well as a global vegetation map and an atmospheric wind circulation patterns diagram, are used as evidence to support the scientific claims they develop through their analysis and interpretation.
NSDL National Science Digital Library
This portal provides access to information on United States Geological Survey (USGS) research activities conducted in support of the U.S. Carbon Cycle Science Program (CCSP). This research includes carbon sequestration in sediments, landscape dynamics and vegetation change, fate of carbon in cold region forests, exchanges of greenhouse gases, water vapor, and heat at the Earth's surface, and other topics. Each topic heading features links to reports or program webpages.
Pingang He; Liming Dai
Owing to their nano-dimensions, rich electronic states, large surface area, high mechanical strength, and excellent chemical\\u000a and thermal stability, carbon nanotubes have attracted a great deal of interest [1]. Among the many potential applications [1, 2], carbon nanotubes have recently become promising functional materials for the development of advanced biosensors with novel\\u000a features. It has been demonstrated that carbon nanotubes
NSDL National Science Digital Library
Catherine Cramer
The most important biochemical reactions for life in the ocean and on Earth are cellular respiration and photosynthesis. These two reactions play a central role in the carbon cycle. The ocean-based carbon cycle is highly relevant to today's students because of its key role in global warming. This experiment allows middle school students to observe the influence of the carbon cycle on algae growth, explore experimental design, collect data, and draw a conclusion.
Wildland Soil Carbon Management
NASA Astrophysics Data System (ADS)
Davis, R. L.; Swanston, C.
In the era of climate change, traditional wildland management practices have come into question, especially with respect to their impact on soil carbon sequestration. Over half of the land area of the United States and Puerto Rico is either in forest or grassland ecosystems, i.e. 302 million hectares of forested lands and 247 million hectares of grasslands and pasture lands. Forested lands hold approximately 35.5 Pg of soil carbon to a depth of 100cm. Private grasslands hold approximately 21 Pg of soil carbon to a depth of 200cm. The difficulty of managing for carbon sequestration becomes more evident when one surveys the variety of complex ecosystems being managed. This presentation highlights implications for wildland management for promoting soil carbon sequestration for sustaining forest and grassland ecosystems in the United States. We will address key considerations, strategies, and opportunities to incorporate soil carbon management into wildland management. Examples of vegetation management influence on soil carbon will be discussed including fire, soil amendments and best management practices for maintaining and/or improving soil carbon sequestration. The USDA Forest Service has established a soil management policy that seeks to conserve soil quality and protect soil carbon on National Forest System lands. Aspects of this national policy will also be presented.
NSDL National Science Digital Library
In this activity, students examine the relationship between carbon dioxide levels and global temperature change by studying a graph of these two variables. They will discover that by using data from ice cores, scientists can determine temperature and carbon dioxide levels in the air as far back as a hundred thousand years in the past. The students try to predict which variable is the independent one and then make a graph of temperature change and carbon dioxide levels. After making their graph, students describe the relationship between temperature and carbon dioxide levels in the atmosphere to determine if their predictions were correct.
Mechanical properties of carbonated concrete
Jiang Jhy Chang; Weichung Yeih; Ran Huang; Jack Maochieh Chi
In this paper, mechanical properties of carbonated concrete were studied. Com?pressive strength, splitting tensile strength, elastic modulus, bond strength and hardness for carbonated concrete subjected to various carbonation conditions were evaluated. Experimental results indicated that all these mechanical properties showed a higher value after carbonation. Especially the bond strength for fully carbonated concrete was about 1.7 that for uncarbonated concrete.
Method for Making a Carbon-Carbon Cylinder Block
NASA Technical Reports Server (NTRS)
Ransone, Phillip O. (Inventor)
A method for making a lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials. such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.
Synthesis and determination of manganese carbonate and manganese-54 carbonate
King, B.D.; Lassiter, J.W.; Neathery, M.W.; Miller, W.J.
A method was developed by which radioactive manganese, manganese-54 carbonate could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. All material was the carbonate form of manganese (manganese-54 carbonate).
Microbially mediated mineral carbonation
NASA Astrophysics Data System (ADS)
Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.
Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O ? (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily implemented and economically efficient alternative to other technologies currently under development for mineral sequestration. Dismukes GC, Carrieri D, Bennette N, Ananyev GM, Posewitz MC (2008) Aquatic phototrophs: efficient alternatives to land-based crops for biofuels. Current Opinion in Biotechnology, 19, 235-240. Ferris FG, Wiese RG, Fyfe WS (1994) Precipitation of carbonate minerals by microorganisms: Implications of silicate weathering and the global carbon dioxide budget. Geomicrobiology Journal, 12, 1-13. Lackner KS, Wendt CH, Butt DP, Joyce EL, Jr., Sharp DH (1995) Carbon dioxide disposal in carbonate minerals. Energy, 20, 1153-1170. Power IM, Wilson SA, Thom JM, Dipple GM, Gabites JE, Southam G (2009) The hydromagnesite playas of Atlin, British Columbia, Canada: A biogeochemical model for CO2 sequestration. Chemical Geology, 206, 302-316. Thompson JB, Ferris FG (1990) Cyanobacterial precipitation of gypsum, calcite, and magnesite from natural alkaline lake water. Geology, 18, 995-998.
Randomly oriented carbon/carbon composite
NASA Astrophysics Data System (ADS)
Raunija, Thakur Sudesh Kumar; Babu, S.
The main objective of this study is to develop an alternate, rapid and cost effective process for the fabrication of carbon/carbon (C/C) composite. Slurry moulding technique is adopted for the fabrication of C/C composite. Randomly oriented hybrid discrete carbon fiber (CF) reinforced and mesophase pitch (MP) derived matrix C/C composite is fabricated. Process parameters are optimized and repeatability is proved. The electrical conductivity of the composite fabricated through the developed process is found to be better than that fabricated through conventional processes. The other properties are also found to be competent. The randomly oriented C/C composite because of its mouldability is found suitable for various applications which require complex shapes.
Sorption of carbon dioxide onto sodium carbonate
Sang-Wook Park; Deok-Ho Sung; Byoung-Sik Choi; Kwang-Joong Oh; Kil-Ho Moon [Pusan National University, Busan (Republic of Korea). Division of Chemical Engineering
Sodium carbonate was used as a sorbent to capture CO{sub 2} from a gaseous stream of carbon dioxide, nitrogen, and moisture. The breakthrough data of CO{sub 2} were measured in a fixed bed to observe the reaction kinetics of CO{sub 2}-carbonate reaction. Several models such as the shrinking-core model, the homogeneous model, and the deactivation model in the non-catalytic heterogeneous reaction systems were used to explain the kinetics of reaction among CO{sub 2}, Na{sub 2}CO{sub 3}, and moisture using analysis of the experimental breakthrough data. Good agreement of the deactivation model was obtained with the experimental breakthrough data. The sorption rate constant and the deactivation rate constant were evaluated by analysis of the experimental breakthrough data using a nonlinear least squares technique and described as Arrhenius form.
The Growth and Characterization of Germanium-Carbon Alloy Thin Films and Solid Phase Equilibria for Metal-Silicon - Ternary Systems: Magnesium, Calcium, Strontium, Barium, Scandium, Yttrium, Lanthanum, Titanium, Zirconium and Hafnium
NASA Astrophysics Data System (ADS)
Yuan, Haojie
Thin films of pure germanium-carbon alloys (Ge _{rm x}C _{rm 1-x} with 0 <=q x <=q 1) have been grown on Si and Al_2O_3 substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray 0-20 diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00 eV to 0.85 eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples have a bonding structure that is a mixture of sp^2 and sp^3 hybridizations. The presence of the sp^2 C is apparently what causes the bandgap of amorphous Ge-C alloys to decrease with increasing carbon concentration. The solidus portion of the ternary phase diagrams of the type M-Si-O, where M = Mg, Ca, Sr, Ba, Sc, Y, La, Ti, Zr and Hf have been derived at 298K and 1 atm oxygen partial pressure by investigating the bulk reactions possible in these systems. These phase diagrams, which have been determined by experiments and by calculations using thermodynamic data available, can be used to predict the occurrence of the reaction products or the stability of the phases present at the interfaces between different solid materials. Hence, they provide guides in designing thin film structures and in selecting candidate materials to form chemically stable interfaces. A research effort has been made on the investigation of the growth of diamond thin films from a carbon containing solid-CI_4, using laser ablation technique. The film grown by laser ablation from CI _4 is mainly composed of carbon with very small amount of oxygen and iodine as indicated by x-ray photoelectron spectroscopy data. The Auger electron spectroscopy result shows that the film grown contains a mixture of sp^2 and sp^3 hybridized carbon. By using x-ray powder diffraction and magnetic susceptibility measurements methods, we studied the chemical stability of candidate interlayer materials between YBa _2Cu_3O _7-delta and Si. The results show that CaF_2 reacts with YBCO while BaF_2 is chemically stable with YBCO. LaGaO_3 and Ca _2SiO_4 are chemically stable with Si and more investigations need to be made on the reactivity between Ca_2SiO _4 and YBCO.
Elevated atmospheric carbon dioxide increases soil carbon
Norby, Richard J [ORNL; Jastrow, Julie D [ORNL; Miller, Michael R [ORNL; Matamala, Roser [Argonne National Laboratory (ANL); Boutton, Thomas W [Texas A& M University; Rice, Charles W [ORNL; Owensby, Clenton E [Kansas State University
In a study funded by the U.S. Department of Energy's Office of Science, researchers from Argonne and Oak Ridge National Laboratories and Kansas State and Texas A&M Universities evaluated the collective results of earlier studies by using a statistical procedure called meta-analysis. They found that on average elevated CO2 increased soil carbon by 5.6 percent over a two to nine year period. They also measured comparable increases in soil carbon for Tennessee deciduous forest and Kansas grassland after five to eight years of experimental exposure to elevated CO2.
NSDL National Science Digital Library
Carbon is the basis of all organic molecules. It is also one of the most abundant elements in the universe. This video segment illustrates the special characteristics of carbon that make it an essential ingredient for life. The segment is one minute thirty-eight seconds in length. A background essay and list of discussion questions are also provided.
ERIC Educational Resources Information Center
Kang, Seong-Joo; Ryu, Eun-Hee
This article presents the development of a carbon dioxide fountain. The advantages of the carbon dioxide fountain are that it is odorless and uses consumer chemicals. This experiment also is a nice visual experiment that allows students to see evidence of a gaseous reagent being consumed when a pressure sensor is available. (Contains 3 figures.)ģ
NASA Technical Reports Server (NTRS)
Bolin, Bert; Fung, Inez
Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.
NASA Technical Reports Server (NTRS)
Pouch, John J.; Alterovitz, Samuel A.
Report describes structure, preparation, characterization, and applications of films of amorphous-carbon. Amorphous-carbon films potentially useful as masks in x-ray lithography, layers for passivation of high-speed microelectronic circuits, hard films to protect magnetic recording media and optical components from degradation by chemical etching or wear, and radiation detectors.
John A. Mathews
Current Kyoto-based approaches to reducing the earth's greenhouse gas problem involve looking for ways to reduce emissions. But these are palliative at best, and at worst will allow the problem to get out of hand. It is only through sequestration of atmospheric carbon that the problem can be solved. Carbon-negative biofuels represent the first potentially huge assault on the problem,
Carbon sequestration by switchgrass
Zhiqin Ma
Increasing levels of carbon dioxide (CO2), which is partly due to use of fossil fuel, is primarily responsible for global climate warming. Producing and using switchgrass for bioenergy can help reduce atmospheric CO2 buildup by partly replacing use of fossil fuels and by carbon (C) sequestration. Switchgrass (Panicum virgatum L) is a potential bioenergy crop suited to the southeastern U.S.
Carbon Energy Flows Belowground
Technology Transfer Automated Retrieval System (TEKTRAN)
Plants use photosynthesis to convert carbon dioxide in the atmosphere and energy from sunlight into energy-containing, carbon-based foodstuffs (i.e. carbohydrates such as sugars and starches) that provide the building blocks for all life on Earth. Without photosynthesis, sunlight would not be a goo...
NASA Technical Reports Server (NTRS)
Sellers, Piers
Model results will be reviewed to assess different methods for bounding the terrestrial role in the global carbon cycle. It is proposed that a series of climate model runs could be scoped that would tighten the limits on the "missing sink" of terrestrial carbon and could also direct future satellite image analyses to search for its geographical location and understand its seasonal dynamics.
NSDL National Science Digital Library
The Science House
In this chemistry activity, learners use common chemicals to produce carbon dioxide and observe its properties. This resource includes brief questions for learners to answer after the experiment. Use this activity to introduce learners to carbon dioxide and its use as a fire extinguisher. Note: this activity involves an open flame.
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 ...
Carbon Dioxide Emission Estimates
NSDL National Science Digital Library
The Carbon Dioxide Information Analysis Center of the Oak Ridge National Laboratory provides this new data on carbon dioxide emissions from fossil fuel burning, hydraulic cement production, and gas flaring in 1995. Data for one degree grid cells can be downloaded from the site in addition to code for analysis of the data.
La Count, Robert B; Baltrus, John P; Kern, Douglas G
A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.
Jon Gibbins; Hannah Chalmers
Carbon capture and storage (CCS) covers a broad range of technologies that are being developed to allow carbon dioxide (CO2) emissions from fossil fuel use at large point sources to be transported to safe geological storage, rather than being emitted to the atmosphere. Some key enabling contributions from technology development that could help to facilitate the widespread commercial deployment of
Atkins, C. A.; Patterson, B. D.; Graham, D.
On the basis of polyacrylamide gradient gel electrophoresis of leaf extracts from 24 species of higher plants, two main forms of carbonic anhydrase (EC 126.96.36.199) were recognized; the ōdicotyledonö type and the ōmonocotyledonö type. More than one band of enzyme was found on gels from most species, suggesting the possibility of carbonic anhydrase isoenzymes in higher plants. Images PMID:16658144
Carbon dioxide disposal in carbonate minerals
Klaus S. Lackner; Christopher H. Wendt; Darryl P. Butt; Edward L. Joyce; David H. Sharp
We introduce a safe and permanent method of CO2 disposal based on combining CO2 chemically with abundant raw materials to form stable carbonate minerals. Substantial heat is liberated in the overall chemical reaction so that cost will be determined by the simplicity and speed of the reaction rather than the cost of energy. Preliminary investigations have been conducted on two
Atmospheric Carbon Dioxide and Carbon Reservoir Changes
Minze Stuiver
The net release of CO2 from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 ū 109 tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th
40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.
Code of Federal Regulations, 2013 CFR
... false Carbon monoxide and carbon dioxide analyzer specifications. 86...316-79 Carbon monoxide and carbon dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made...
40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.
Code of Federal Regulations, 2010 CFR
... false Carbon monoxide and carbon dioxide analyzer specifications. 86...316-79 Carbon monoxide and carbon dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made...
40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.
Code of Federal Regulations, 2011 CFR
... false Carbon monoxide and carbon dioxide analyzer specifications. 86...316-79 Carbon monoxide and carbon dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made...
40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.
Code of Federal Regulations, 2012 CFR
... false Carbon monoxide and carbon dioxide analyzer specifications. 86...316-79 Carbon monoxide and carbon dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made...
Trading Water for Carbon with Biological Carbon Sequestration
Nacional de San Luis, Universidad
Trading Water for Carbon with Biological Carbon Sequestration Robert B. Jackson,1 * Esteban G. Farley,1 David C. le Maitre,5 Bruce A. McCarl,6 Brian C. Murray7 Carbon sequestration strategies plantations feature prominently among tools for carbon sequestration (1Ł8). Plantations typi- cally combine
A novel carbon fiber based porous carbon monolith
Burchell, T.D.; Klett, J.W.; Weaver, C.E.
A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials will find applications in the field of fluid separations or as a catalyst support. Here, the manufacture and characterization of our porous carbon monoliths are described.
Pistons and Cylinders Made of Carbon-Carbon Composite Materials
NASA Technical Reports Server (NTRS)
Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)
An improved reciprocating internal combustion engine has a plurality of engine pistons, which are fabricated from carbon---carbon composite materials, in operative association with an engine cylinder block, or an engine cylinder tube, or an engine cylinder jug, all of which are also fabricated from carbon-carbon composite materials.
Pistons and Cylinders Made of Carbon-Carbon Composite Materials
NASA Technical Reports Server (NTRS)
Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)
An improved reciprocating internal combustion engine has a plurality of engine pistons, which are fabricated from carbon-carbon composite materials, in operative association with an engine cylinder block, or an engine cylinder tube, or an engine cylinder jug, all of which are also fabricated from carbon-carbon composite materials.
Carbon Recycling: An Alternative to Carbon Capture and Storage
Rowan Oloman
Carbon capture and storage (CCS) is a classical ōend of the pipeö techno-fix for the problem of carbon dioxide pollution of Earth's atmosphere. In contrast, carbon recycling has the potential to be a partial alternative to CCS that could shift the whole paradigm of the generation and use of energy. Many innovative carbon recycling methods are currently being pursued, including
Schrag, Daniel P
Carbon sequestration from large sources of fossil fuel combustion, particularly coal, is an essential component of any serious plan to avoid catastrophic impacts of human-induced climate change. Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon dioxide emissions over the next century. The challenge is whether the technology will be ready when society decides that it is time to get going. PMID:17289991
Schrag, D.P. [Harvard University, Cambridge, MA (United States)
Carbon sequestration from large sources of fossil fuel combustion, particularly coal, is an essential component of any serious plan to avoid catastrophic impacts of human-induced climate change. Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon dioxide emissions over the next century. The challenge is whether the technology will be ready when society decides that it is time to get going.
Introduction to Carbon Nanotubes
NASA Astrophysics Data System (ADS)
Monthioux, Marc; Serp, Philippe; Flahaut, Emmanuel; Razafinimanana, Manitra; Laurent, Christophe; Peigney, Alain; Bacsa, Wolfgang; Broto, Jean-Marc
Carbon nanotubes are among the amazing objects that science sometimes creates by accident, without meaning to, but that will likely revolutionize the technological landscape of the century ahead. Our society stands to be significantly influenced by carbon nanotubes, shaped by nanotube applications in every aspect, just as silicon-based technology still shapes society today. The world already dreams of space-elevators tethered by the strongest of cables, hydrogen-powered vehicles, artificial muscles, and so on - feasts that would be made possible by the emerging carbon nanotube science.
NSDL National Science Digital Library
In this activity, learners take on the role of a carbon atom and record which reservoirs in the carbon cycle they visit. Learners will compare and contrast their trip with those of other learners to discover information about sources and sinks, and residence times of the different reservoirs. Ocean processes are highlighted to allow the educator to define the biological pump and explain its importance to climate. Helping learners understand the carbon cycle is essential to their understanding of the causes and consequences of climate change.
Taxonomy by Carbon Replication
Dietz, Alma; Mathews, John
Pre-shadowed carbon replication of spore surfaces (carbon repligraphy) provides a new technique for the characterization of streptomycetes. Carbon repligraphs of five members of the Streptomyces hygroscopicus complex show two distinct types. Type I shows a nonsegmented spore structure with an extremely wrinkled surface. Type II has a segmented spore chain with detailed surface structure resembling a basket weave. Images FIG. 1 FIG. 2 FIG. 3 FIG. 4 FIG. 5 FIG. 6 FIG. 7 FIG. 8 FIG. 9 FIG. 10 FIG. 11 FIG. 12 FIG. 13 FIG. 14 FIG. 15 FIG. 16 FIG. 17 PMID:13886326
Carbon Nanotubes in Neuroscience
Malarkey, Erik B.
Carbon nanotubes have electrical, mechanical and chemical properties that make them one of the most promising materials for applications in neuroscience. Single-walled and multi-walled carbon nanotubes have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. They are also used in interfaces with neurons, where they can detect neuronal electrical activity and also deliver electrical stimulation to these cells. The emerging picture is that carbon nanotubes do not have obvious adverse effects on mammalian health. Thus in the near future they could be used in brain¢machine interfaces. PMID:19812974
NSDL National Science Digital Library
British Petroleum
This site is produced by British Petroleum and provides a simple, interactive guide to estimate your annual household carbon emissions. The calculator asks questions about the features of your residence, car travel, air travel and recycling habits. As each question is answered, a graph displays the carbon emissions so you can see the effects of each of the options presented. This tool is intended as an approximate guide only, but is useful for stimulating an awareness of the approximate amount of carbon dioxide emitted by everyday tasks.
Porous carbons prepared by direct carbonization of MOFs for supercapacitors
NASA Astrophysics Data System (ADS)
Yan, Xinlong; Li, Xuejin; Yan, Zifeng; Komarneni, Sridhar
Three porous carbons were prepared by direct carbonization of HKUST-1, MOF-5 and Al-PCP without additional carbon precursors. The carbon samples obtained by carbonization at 1073 K were characterized by XRD, TEM and N2 physisorption techniques followed by testing for electrochemical performance. The BET surface areas of the three carbons were in the range of 50-1103 m2/g. As electrode materials for supercapacitor, the MOF-5 and Al-PCP derived carbons displayed the ideal capacitor behavior, whereas the HKUST-1 derived carbon showed poor capacitive behavior at various sweep rates and current densities. Among those carbon samples, Al-PCP derived carbons exhibited highest specific capacitance (232.8 F/g) in 30% KOH solution at the current density of 100 mA/g.
Resistivity of Carbon-Carbon Composites Halved
NASA Technical Reports Server (NTRS)
Gaier, James R.
Carbon-carbon composites have become the material of choice for applications requiring strength and stiffness at very high temperatures (above 2000 C). These composites comprise carbon or graphite fibers embedded in a carbonized or graphitized matrix. In some applications, such as shielding sensitive electronics in very high temperature environments, the performance of these materials would be improved by lowering their electrical resistivity. One method to lower the resistivity of the composites is to lower the resistivity of the graphite fibers, and a proven method to accomplish that is intercalation. Intercalation is the insertion of guest atoms or molecules into a host lattice. In this study the host fibers were highly graphitic pitch-based graphite fibers, or vapor-grown carbon fibers (VGCF), and the intercalate was bromine. Intercalation compounds of graphite are generally thought of as being only metastable, but it has been shown that the residual bromine graphite fiber intercalation compound is remarkably stable, resisting decomposition even at temperatures at least as high as 1000 C. The focus of this work was to fabricate composite preforms, determine whether the fibers they were made from were still intercalated with bromine after processing, and determine the effect on composite resistivity. It was not expected that the resistivity would be lowered as dramatically as with graphite polymer composites because the matrix itself would be much more conductive, but it was hoped that the gains would be substantial enough to warrant its use in high-performance applications. In a collaborative effort supporting a Space Act Agreement between the NASA Glenn Research Center and Applied Sciences, Inc. (Cedarville, OH), laminar preforms were fabricated with pristine and bromine-intercalated pitch-based fibers (P100 and P100-Br) and VGCF (Pyro I and Pyro I-Br). The green preforms were carbonized at 1000 C and then heat treated to 3000 C. To determine whether the fibers in the samples were still intercalated after composite fabrication, they were subjected to X-ray diffraction. The composites containing intercalated graphite fibers showed much higher background scatter than that of pristine fibers, indicating the presence of bromine in the samples. More importantly, faint features indicative of intercalation were visible in the diffraction pattern, showing that the fibers were still intercalated.
Synthesis and determination of manganese carbonate and manganese-54 carbonate
B. D. King; J. W. Lassiter; M. W. Neathery; W. J. Miller
A method was developed by which radioactive manganese, manganese-54 carbonate could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. All material was the carbonate form of manganese
Carbon Nanotubes: Synthesis and Characterization
Yamini Yadav; Vindhya Kunduru; Shalini Prasad
Carbon can form various types of structurally different frameworks due to the ability of the carbon atoms to form different species of valence bonds. The extremely organized coagulation process of carbon molecules resulting in the formation of the perfectly symmetric fullerene molecule despite the chaotic environment of the carbon arc is truly fascinating. Although many formation theories for the buckyball
Method for synthesizing carbon nanotubes
Fan, Hongyou
A method for preparing a precursor solution for synthesis of carbon nanomaterials, where a polar solvent is added to at least one block copolymer and at least one carbohydrate compound, and the precursor solution is processed using a self-assembly process and subsequent heating to form nanoporous carbon films, porous carbon nanotubes, and porous carbon nanoparticles.
AMAZING CARBON Prof. David Tomnek
years, elemental carbon, found in sp2 bonded graphite or sp3 bonded diamond, was believed to be well. In any case, it appears that elemental carbon will not cease amazing us with an ever growing varietyAMAZING CARBON Prof. David Tomßnek Carbon does not stop amazing us Ł again and again. For many
Estimating carbon monoxide exposure
NASA Technical Reports Server (NTRS)
Edgerley, R. H.
Method predicts effects of carbon monoxide on astronauts confined in spacecraft cabin atmospheres. Information on need for low toxicity level also applies to confined spaces. Benefits are applicable to industry and public health.
Marc J. Kuchner; S. Seager
We suggest that some extrasolar planets planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local enhancement of the protoplanetary disk's C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune-mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures.
Bruce, J.P. [Soil and Water Conservation Society, Ottawa, Ontario (Canada); Frome, M. [Soil and Water Conservation Society, Washington, DC (United States); Haites, E. [Margaree Consultants, Toronto, Ontario (Canada); Janzen, H. [Agriculture and Agri-Food Canada, Lethbridge, Alberta (Canada); Lal, R. [Ohio State Univ., Columbus, OH (United States). School of Natural Resources; Paustian, K. [Colorado State Univ., Fort Collins, CO (United States). Natural Resource Ecology Lab.
The purpose of this article is to examine (a) the magnitude of the potential for carbon sequestration in the soil as a means of reducing carbon dioxide (CO{sub 2}) in the atmosphere, (b) some of the measures that might be used to achieve this potential, (c) the methods available for estimating carbon sequestration on a farm or regional level, (d) what is needed to achieve international consensus, and (e) additional information needs. This article is not presented as a definitive document but rather as an overview of where scientific opinion converges and where more work is needed. In addition, it aims to provoke discussion of the measures that can increase soil carbon sequestration and the policies that might be used to implement those measures.
Global terrestrial carbon cycle
Smith, T.M.; Cramer, W.P.; Dixon, R.K.; Leemans, R.; Neilson, R.P.
There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle. The uncertainty arises from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO2 on natural ecosystems. Despite these limitations, a number of studies have estimated current and future patterns of terrestrial carbon storage. Future estimates focus on the effects of a climate change associated with a doubled atmospheric concentration of CO2. Available models for examining the dynamics of terrestrial carbon storage and the potential role of forest management and landuse practices on carbon conservation and sequestration are discussed. (Copyright (c) 1993 Kluwer Academic Publishers.)
A revision to the 1971 original, it presents information on design considerations and descriptions of existing and planned applications of granular activated carbon adsorption in the treatment of municipal wastewaters....
Kales, S.N. (Cambridge Hospital, MA (United States))
Carbon monoxide poisoning usually results from inhalation of exhaust fumes from motor vehicles, smoke from fires or fumes from faulty heating systems. Carbon monoxide has a high affinity for hemoglobin, with which it forms carboxyhemoglobin. The resulting decrease in both oxygen-carrying capacity and oxygen release can lead to end-organ hypoxia. The clinical presentation is nonspecific. Headache, dizziness, fatigue and nausea are common in mild to moderate carbon monoxide poisoning. In more severe cases, tachycardia, tachypnea and central nervous system depression occur. When carbon monoxide intoxication is suspected, empiric treatment with 100 percent oxygen should be initiated immediately. The diagnosis is confirmed by documenting an elevated carboxyhemoglobin level. Hyperbaric oxygen therapy is recommended in patients with neurologic dysfunction, cardiac dysfunction or a history of unconsciousness. 26 refs.
Carbon Monoxide Information Center
MedlinePLUS Videos and Cool Tools
... Safety Blogs: CO Safety More CO Blogs Research & Statistics January 08, 2015 Non-Fire Carbon Monoxide Deaths ... Engine-Driven Tools View All CO-Related Injury Statistics and Technical Reports Inside CPSC: Recalls Safety Education ...
Carbon Nanotube Memory Elements
Meunier, Vincent [ORNL; Sumpter, Bobby G [ORNL
Carbon nanotubes are among the most cited prototypical materials for nanoelectronics and information storage devices, a dominant position that originates from their intrinsic structural and electronic properties. In this chapter we review the developments in memory elements that directly exploit the unique properties of carbon nanotubes. Fundamental operational principles and characteristics are examined for the different types of carbon nanotube-based memory devices along with the current status of experimental fabrication and scalability. These include memory elements based on carbon nanotube field-effect transistors (CNFET), nanoelectromechanical systems (NEMS), and electromigration. Many of these devices show tremendous promise for providing enhanced densities, lower power requirements, more efficient read/write processes, and non-volatility of data.
Carbon nanotubes: Fibrillar pharmacology
NASA Astrophysics Data System (ADS)
Kostarelos, Kostas
The mechanisms by which chemically functionalized carbon nanotubes flow in blood and are excreted through the kidneys illustrate the unconventional behaviour of these fibrillar nanostructures, and the opportunities they offer as components for the design of advanced delivery vehicles.
NSDL National Science Digital Library
WGBH Educational Foundation
In this interactive activity adapted from NOVA, learn about alkaloids and steroids, both examples of compounds with carbon rings. Short videos with interviews,animations, and photographs are featured.
Method of manufacturing carbon nanotubes
NASA Technical Reports Server (NTRS)
Benavides, Jeanette M. (Inventor); Leidecker, Henning W. (Inventor); Frazier, Jeffrey (Inventor)
A process for manufacturing carbon nanotubes, including a step of inducing electrical current through a carbon anode and a carbon cathode under conditions effective to produce the carbon nanotubes, wherein the carbon cathode is larger than the carbon anode. Preferably, a welder is used to induce the electrical current via an arc welding process. Preferably, an exhaust hood is placed on the anode, and the process does not require a closed or pressurized chamber. The process provides high-quality, single-walled carbon nanotubes, while eliminating the need for a metal catalyst.
NSDL National Science Digital Library
California Academy of Sciences
In this activity, learners gain knowledge about how carbon moves through all four of the EarthÆs major spheres (biosphere, hydrosphere, atmosphere, and lithosphere), and understand how humans influence the carbon cycle and contribute to global climate change. Learners work in groups to create a diagram to show how the Earth's major spheres are connected by diffusion, respiration, burial, and weathering. This detailed lesson plan includes key vocabulary words, discussion questions, resources for educators, and is standards-based.
Prokaryotic carbonic anhydrases
Kerry S Smith; James G Ferry
Carbonic anhydrases catalyze the reversible hydration of CO2 [CO2+H2O?HCO3?+H+]. Since the discovery of this zinc (Zn) metalloenzyme in erythrocytes over 65 years ago, carbonic anhydrase has not only been found in virtually all mammalian tissues but is also abundant in plants and green unicellular algae. The enzyme is important to many eukaryotic physiological processes such as respiration, CO2 transport and
Carbon dioxide removal process
Baker, Richard W.; Da Costa, Andre R.; Lokhandwala, Kaaeid A.
A process and apparatus for separating carbon dioxide from gas, especially natural gas, that also contains C.sub.3+ hydrocarbons. The invention uses two or three membrane separation steps, optionally in conjunction with cooling/condensation under pressure, to yield a lighter, sweeter product natural gas stream, and/or a carbon dioxide stream of reinjection quality and/or a natural gas liquids (NGL) stream.
What is carbon? Carbon is every where
Tsymbal, Evgeny Y.
! #12;Metallic 1/3: Metallic 2/3: Semiconducting Metallic CNT Copper 4ū109 A/cm2 ~ 106 A/cm2 1000 times than Copper In axis direction In radial direction Highly anisotropic thermal conductivity ! #12;How://www.youtube.com/watch?v=wOu4QWpG5to #12;How carbon nanostructures can be used? Vertical aligned CNTs lead to superhydrophobic
Carbon Characterization Laboratory Report
David Swank; William Windes; D.C. Haggard; David Rohrbaugh; Karen Moore
The newly completed Idaho National Laboratory (INL) Carbon Characterization Laboratory (CCL) is located in Lab-C20 of the Idaho National Laboratory Research Center. This laboratory was established under the Next Generation Nuclear Plant (NGNP) Project to support graphite research and development activities. The CCL is designed to characterize and test carbon-based materials such as graphite, carbon-carbon composites, and silicon-carbide composite materials. The laboratory is fully prepared to measure material properties for nonirradiated carbon-based materials. Plans to establish the laboratory as a radiological facility within the next year are definitive. This laboratory will be modified to accommodate irradiated materials, after which it can be used to perform material property measurements on both irradiated and nonirradiated carbon-based material. Instruments, fixtures, and methods are in place for preirradiation measurements of bulk density, thermal diffusivity, coefficient of thermal expansion, elastic modulus, YoungÆs modulus, Shear modulus, Poisson ratio, and electrical resistivity. The measurement protocol consists of functional validation, calibration, and automated data acquisition.
Carbon based prosthetic devices
Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.
NASA Astrophysics Data System (ADS)
Houghton, R. A.
The global carbon cycle refers to the exchanges of carbon within and between four major reservoirs: the atmosphere, the oceans, land, and fossil fuels. Carbon may be transferred from one reservoir to another in seconds (e.g., the fixation of atmospheric CO2 into sugar through photosynthesis) or over millennia (e.g., the accumulation of fossil carbon (coal, oil, gas) through deposition and diagenesis of organic matter). This chapter emphasizes the exchanges that are important over years to decades and includes those occurring over the scale of months to a few centuries. The focus will be on the years 1980-2000 but our considerations will broadly include the years ś1850-2100. Chapter 8.09, deals with longer-term processes that involve rates of carbon exchange that are small on an annual timescale (weathering, vulcanism, sedimentation, and diagenesis).The carbon cycle is important for at least three reasons. First, carbon forms the structure of all life on the planet, making up ś50% of the dry weight of living things. Second, the cycling of carbon approximates the flows of energy around the Earth, the metabolism of natural, human, and industrial systems. Plants transform radiant energy into chemical energy in the form of sugars, starches, and other forms of organic matter; this energy, whether in living organisms or dead organic matter, supports food chains in natural ecosystems as well as human ecosystems, not the least of which are industrial societies habituated (addicted?) to fossil forms of energy for heating, transportation, and generation of electricity. The increased use of fossil fuels has led to a third reason for interest in the carbon cycle. Carbon, in the form of carbon dioxide (CO2) and methane (CH4), forms two of the most important greenhouse gases. These gases contribute to a natural greenhouse effect that has kept the planet warm enough to evolve and support life (without the greenhouse effect the Earth's average temperature would be -33░C). Additions of greenhouse gases to the atmosphere from industrial activity, however, are increasing the concentrations of these gases, enhancing the greenhouse effect, and starting to warm the Earth.The rate and extent of the warming depend, in part, on the global carbon cycle. If the rate at which the oceans remove CO2 from the atmosphere were faster, e.g., concentrations of CO2 would have increased less over the last century. If the processes removing carbon from the atmosphere and storing it on land were to diminish, concentrations of CO2 would increase more rapidly than projected on the basis of recent history. The processes responsible for adding carbon to, and withdrawing it from, the atmosphere are not well enough understood to predict future levels of CO2 with great accuracy. These processes are a part of the global carbon cycle.Some of the processes that add carbon to the atmosphere or remove it, such as the combustion of fossil fuels and the establishment of tree plantations, are under direct human control. Others, such as the accumulation of carbon in the oceans or on land as a result of changes in global climate (i.e., feedbacks between the global carbon cycle and climate), are not under direct human control except through controlling rates of greenhouse gas emissions and, hence, climatic change. Because CO2 has been more important than all of the other greenhouse gases under human control, combined, and is expected to continue so in the future, understanding the global carbon cycle is a vital part of managing global climate.This chapter addresses, first, the reservoirs and natural flows of carbon on the earth. It then addresses the sources of carbon to the atmosphere from human uses of land and energy and the sinks of carbon on land and in the oceans that have kept the atmospheric accumulation of CO2 lower than it would otherwise have been. The chapter describes changes in the distribution of carbon among the atmosphere, oceans, and terrestrial ecosystems over the past 150 years as a result of human-induced emissions of carbon. The processes responsible fo
Thermal oxidation of carbon nanomaterials
NASA Astrophysics Data System (ADS)
Glebova, N. V.; Nechitailov, A. A.; Kukushkina, Yu. A.; Sokolov, V. V.
The process of the thermal oxidation of various carbon nanomaterials (multiwalled carbon nanotubes, carbon black, nanoporous carbon and graphite) used in the catalytic layers of electrochemical energy converters (electrolyzers, fuel cells) has been studied. The thermal stability of these materials has been determined. Relationships between the structural characteristics of carbon nanomaterials and the parameters of their thermal oxidation in air have determined using the methods of differential thermal analysis and adsorption-structure analysis.
Mechanistical studies on the formation and destruction of carbon monoxide (CO), carbon dioxide (CO2), and carbon trioxide (CO3)
Kaiser, Ralf I.
Mechanistical studies on the formation and destruction of carbon monoxide (CO), carbon dioxide (CO2 monoxide (CO), carbon dioxide (CO2), and molecular oxygen (O2) with varying carbon-to-oxygen ratios from 1 and destruction pathways of carbon monoxide (CO), carbon dioxide (CO2), and carbon trioxide (CO3
Studies and characterisations of various activated carbons used for carbon\\/carbon supercapacitors
J Gamby; P. L Taberna; P Simon; J. F Fauvarque; M Chesneau
Various activated carbons from the PICA Company have been tested in supercapacitor cells in order to compare their performances. The differences measured in terms of specific capacitance and cell resistance are presented. Porosity measurements made on activated carbon powders and electrode allowed a better understanding of the electrochemical behaviour of these activated carbons. In this way, the PICACTIF SC carbon
Implications of carbon dust emission for terrestrail carbon cycling and carbon accounting
Technology Transfer Automated Retrieval System (TEKTRAN)
Wind erosion preferentially removes the finest carbon- and nutrient-rich soil fractions, and consequently its role may be significant within terrestrial carbon (C) cycles. However, the impacts of wind erosion on soil organic carbon (SOC) redistribution are not considered in most carbon cycle models,...
Microbially mediated carbon mineralization: Geoengineering a carbon-neutral mine
NASA Astrophysics Data System (ADS)
Power, I. M.; McCutcheon, J.; Harrison, A. L.; Wilson, S. A.; Dipple, G. M.; Southam, G.
Ultramafic and mafic mine tailings are a potentially valuable feedstock for carbon mineralization, affording the mining industry an opportunity to completely offset their carbon emissions. Passive carbon mineralization has previously been documented at the abandoned Clinton Creek asbestos mine, and the active Diavik diamond mine and Mount Keith nickel mine, yet the majority of tailings remain unreacted. Examples of microbe-carbonate interactions at each mine suggest that biological pathways could be harnessed to promote carbon mineralization. In suitable environmental conditions, microbes can mediate geochemical processes to accelerate mineral dissolution, increase the supply of carbon dioxide (CO2), and induce carbonate precipitation, all of which may accelerate carbon mineralization. Tailings mineralogy and the availability of a CO2 point source are key considerations in designing tailings storage facilities (TSF) for optimizing carbon mineralization. We evaluate the efficacy of acceleration strategies including bioleaching, biologically induced carbonate precipitation, and heterotrophic oxidation of waste organics, as well as abiotic strategies including enhancing passive carbonation through modifying tailings management practices and use of CO2 point sources (Fig. 1). With the aim of developing carbon-neutral mines, implementation of carbon mineralization strategies into TSF design will be driven by economic incentives and public pressure for environmental sustainability in the mining industry. Figure 1. Schematic illustrating geoengineered scenarios for carbon mineralization of ultramafic mine tailings. Scenarios A and B are based on non-point and point sources of CO2, respectively.
Carbon isotope effects in carbonate systems
NASA Astrophysics Data System (ADS)
Deines, Peter
Global carbon cycle models require a complete understanding of the ? 13C variability of the Earth's C reservoirs as well as the C isotope effects in the transfer of the element among them. An assessment of ? 13C changes during CO 2 loss from degassing magmas requires knowledge of the melt-CO 2 carbon isotope fractionation. In order to examine the potential size of this effect for silicate melts of varying composition, 13C reduced partition functions were computed in the temperature range 275 to 4000 K for carbonates of varying bond strengths (Mg, Fe, Mn, Sr, Ba, Pb, Zn, Cd, Li, and Na) and the polymorphs of calcite. For a given cation and a given pressure the 13C content increases with the density of the carbonate structure. For a given structure the tendency to concentrate 13C increases with pressure. The effect of pressure (ē/10 kbar) on the size of the reduced partition function of aragonite varies with temperature; in the pressure range 1 to 10 5 bars the change is given by: ? 13C p average=-0.01796+0.06635? 10 3/T+0.006875? 10 6/T2 For calcite III the pressure effect is on average 1.4ū larger than that for aragonite at all temperatures. The nature of the cation in a given structure type has a significant effect on the carbon isotope fractionation properties. The tendency to concentrate 13C declines in the series magnesite, aragonite, dolomite, strontianite, siderite, calcite, smithonite, witherite, rhodochrosite, otavite, cerrusite. For divalent cations a general expression for an estimation of the reduced partition function (?) from the reduced mass (? = [M Cation ū M Carbonate]/[M Cation + M Carbonate]) is: 1000 ln?=(0.032367-0.072563? 10 3/T-0.01073? 10 6/T2)??-14.003+29.953? 10 3/T+9.4610? 10 6/T2 For Mg-calcite the 13C content varies with the Mg concentration. The fractionation between Mg-calcite (X = mole fraction of MgCO 3) and calcite is given by: 1000 ln(? MgCalite- Calcite)=[0.013702-0.10957ū 10 3/T+1.35940ū 10 6/T2-0.329124ū 10 9/T3+0.0304160ū 10 12/T4]ū X1.5 The results of the computations were used together with previously published experimental vaporous CO 2-silicate melt fractionations to determine, at 1200░C, a relationship between melt-CO 213C fractionation and melt composition, expressed as molecular proportions of the cations Mg, Fe, Mn, Ca, Na, K and Si and Al: 1000 ln? Melt- CO2=5.14ū Mg+ Fe+ Mn+ Ca+ Na+ K/Si+ Al+0.86 A conceptual model to understand this relationship was developed. The results of the computations approximate closely the experimentally determined vaporous CO 2-CaCO 3 fractionations at high temperatures. Empirically derived dolomite-calcite and calcite-graphite 13C isotope geothermometers agree with results of the present work.
The West Coast Regional Carbon Sequestration Partnership (known as WESTCARB) was established in Fall 2003. It is one of seven research partnerships co-funded by DOE to characterize regional carbon sequestration opportunities and conduct pilot-scale validation tests. The California Energy Commission manages WESTCARB and is a major co-funder. WESTCARB is characterizing the extent and capacity of geologic formations capable of storing CO2, known as sinks. Results are entered into a geographic information system (GIS) database, along with the location of major CO2-emitting point sources in each of the six WESTCARB states, enabling researchers and the public to gauge the proximity of candidate CO2 storage sites to emission sources and the feasibility of linking them via pipelines. Specifically, the WESTCARB GIS database (also known as the carbon atlas) stores layers of geologic information about potential underground storage sites, such as porosity and nearby fault-lines and aquifers. Researchers use these data, along with interpreted geophysical data and available oil and gas well logs to estimate the region's potential geologic storage capacity. The database also depicts existing pipeline routes and rights-of-way and lands that could be off-limits, which can aid the development of a regional carbon management strategy. The WESTCARB Carbon Atlas, which is accessible to the public, provides a resource for public discourse on practical solutions for regional CO2 management. A key WESTCARB partner, the Utah Automated Geographic Reference Center, has developed data serving procedures to enable the WESTCARB Carbon Atlas to be integrated with those from other regional partnerships, thereby supporting the U.S. Department of Energy's national carbon atlas, NATCARB
Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells
Cooper, John F. (Oakland, CA); Cherepy, Nerine (Oakland, CA)
A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.
Response of carbon-carbon composites to challenging environments
NASA Technical Reports Server (NTRS)
Maahs, Howard G.; Ohlhorst, Craig W.; Barrett, David M.; Ransone, Philip O.; Sawyer, J. Wayne
This paper presents results from material performance evaluations of oxidation-resistant carbon-carbon composites intended for multiuse aerospace applications, which cover the effects of the following environmental parameters: the oxidizing nature of the environments (including both high and low oxygen partial pressures), high temperatures, moisture, cyclic temperature service, and foreign-object impact. Results are presented for the carbon-carbon material currently in use as the thermal-protection-system material on Space Shuttle, as well as for newer and more advanced structural forms of carbon-carbon composites.
Carbon microstructures for electrochemical studies
Kostecki, Robert; Song, Xiang Yun; Kinoshita, Kim
Thin layers of photoresist were spin coated onto silicon wafers, and then carbonized to form smooth carbon films by heating in nitrogen for 1 hour at temperatures between 600 to 1100 C. Well-defined carbon microstructures on Si wafers that are being considered for electrodes in a microbattery concept were obtained by additional processing steps involving patterning and lithography of the photoresist prior to carbonization. The status of the fabrication of carbon microelectrodes obtained by pyrolysis of photoresist, characterization of the carbons by surface-sensitive techniques and electrochemical analysis by cyclic voltammetry of the I{sup -}/I{sub 3}{sup -} redox reaction is described.
Carbon Chemistry in interstellar clouds
Maryvonne Gerin; David Fosse; Evelyne Roueff
We discuss new developments of interstellar chemistry, with particular emphasis on the carbon chemistry. We confirm that carbon chains and cycles are ubiquitous in the ISM and closely chemically related to ea ch other, and to carbon. Investigation of the carbon budget in shielded and UV illuminated gas shows that the inventory of interstellar molecules is not complete and more complex molecules with 4 or more carbon atoms must be present. Finally we discuss the consequences for the evolution of clouds and conclude that the ubiquitous presence of carbon chains and cycles is not a necessary consequence of a very young age for interstellar clouds.
Synthesis and determination of manganese carbonate and manganese-54 carbonate.
King, B D; Lassiter, J W; Neathery, M W; Miller, W J
A method was developed by which radioactive manganese, manganese-54 carbonate (with a high specific activity), could be produced. This was accomplished by reacting manganese-54 chloride, manganese chloride tetrahydrate, and sodium bicarbonate. This reaction produced manganese-54 carbonate (specific activity .35 mCi/mg manganese mixed with stable manganese. The purity of the manganese carbonate (manganese-54 carbonate) was determined by the use of x-ray diffraction methods. One method compared "d" spacings (distance in angstroms between lattice planes of a crystal) with standard and index values for pure manganese carbonate. Another method compared x-ray diffractograms of the synthesized product with standard manganese carbonate. By both methods all material was the carbonate form of manganese (manganese-54 carbonate). PMID:7381087
Carbon Cycle: Exchanging Carbon Dioxide between the Atmosphere and Ocean
NSDL National Science Digital Library
This lab investigates the exchange of carbon dioxide between the atmosphere and the ocean's surface. It is based on the fact that carbon dioxide dissolves in the ocean and provides the source of that plants and plankton living in the ocean rely on for photosynthesis. Students will discover that the amount of carbon dioxide the ocean can contain depends on the temperature of the water and its salinity (whether it is sea water or fresh water) and that cold water can hold more carbon dioxide in solution than warm water. They will observe that when carbon dioxide dissolves in water, it forms carbonic acid which makes the water acidic, and they will test for the acidity caused by the presence of dissolved carbon dioxide using Universal Indicator, which turns yellow when the solution is acidic. This activity tests whether sea water or fresh water absorbs more carbon dioxide.
NASA Astrophysics Data System (ADS)
Bird, Michael I.; Wynn, Jonathan G.; Saiz, Gustavo; Wurster, Christopher M.; McBeath, Anna
Pyrogenic carbon (PyC; includes soot, char, black carbon, and biochar) is produced by the incomplete combustion of organic matter accompanying biomass burning and fossil fuel consumption. PyC is pervasive in the environment, distributed throughout the atmosphere as well as soils, sediments, and water in both the marine and terrestrial environment. The physicochemical characteristics of PyC are complex and highly variable, dependent on the organic precursor and the conditions of formation. A component of PyC is highly recalcitrant and persists in the environment for millennia. However, it is now clear that a significant proportion of PyC undergoes transformation, translocation, and remineralization by a range of biotic and abiotic processes on comparatively short timescales. Here we synthesize current knowledge of the production, stocks, and fluxes of PyC as well as the physical and chemical processes through which it interacts as a dynamic component of the global carbon cycle.
Carbon Fibers Conductivity Studies
NASA Technical Reports Server (NTRS)
Yang, C. Y.; Butkus, A. M.
In an attempt to understand the process of electrical conduction in polyacrylonitrile (PAN)-based carbon fibers, calculations were carried out on cluster models of the fiber consisting of carbon, nitrogen, and hydrogen atoms using the modified intermediate neglect of differential overlap (MINDO) molecular orbital (MO) method. The models were developed based on the assumption that PAN carbon fibers obtained with heat treatment temperatures (HTT) below 1000 C retain nitrogen in a graphite-like lattice. For clusters modeling an edge nitrogen site, analysis of the occupied MO's indicated an electron distribution similar to that of graphite. A similar analysis for the somewhat less stable interior nitrogen site revealed a partially localized II electron distribution around the nitrogen atom. The differences in bonding trends and structural stability between edge and interior nitrogen clusters led to a two-step process proposed for nitrogen evolution with increasing HTT.
Wisconsin at Madison, University of
ISSUES IN EVALUATING CARBON SEQUESTRATION AND ATTRIBUTING CARBON CREDITS TO GRASSLAND RESTORATION examines biological carbon sequestration using a grassland restoration as a model system. Chapter 1 for biological carbon sequestration. In this analysis, we found that significantly greater soil carbon
Potassium intercalation of carbon onions æopenedÆ by carbon dioxide treatment
Yu. V. Butenko; Amit K. Chakraborty; N. Peltekis; S. Krishnamurthy; V. R. Dhanak; M. R. C. Hunt; L. Ŗiller
The potassium intercalation of onion-like carbon (OLC) samples consisting of aggregates of carbon onions is studied with photoemission spectroscopy. OLC samples were initially prepared by annealing nanodiamonds (3¢20nm in diameter) at 1800K in vacuum. The resulting OLC consists of closed fullerene-like shells. The æclosedÆ OLC was subsequently treated with carbon dioxide at 1020K in order to open the carbon shells
Thermal properties of aligned carbon nanotube\\/carbon nanocomposites
Qian-ming Gong; Zhi Li; Xiao-dong Bai; Dan Li; Yun Zhao; Ji Liang
Aligned carbon nanotube\\/carbon (Acnt\\/C) nanocomposites were fabricated with traditional chemical vapor infiltration (CVI) technology. Thermal conductivities of as-deposited and graphitized samples were tested by laser flash method. Results show that although only half the density and half the fraction of reinforcing element compared with carbon\\/carbon (C\\/C) composites in this work, the thermal diffusivity of Acnt\\/C is generally 3¢5 times that
NASA Astrophysics Data System (ADS)
Caldeira, Ken
Human emissions of CO2 now outpace natural sources by two orders of magnitude. The current concentration of CO2 has not been substantially exceeded in the past 30 million years. Multiple model exercises indicate that consuming all fossil fuels would result in concentrations more than double present levels, even after 10,000 years. The global warming effect of carbon emissions appears within 5-7 years. However, since the effect of present infrastructure over its expected life would only modestly increase CO2 concentrations and global temperature, human choices over its replacement will decisively influence ultimate carbon impacts, both short-term and long-term.
NSDL National Science Digital Library
Randy Richardson
In this activity, students work in groups, plotting carbon dioxide concentrations over time on overheads and estimating the rate of change over five years. Stacked together, the overheads for the whole class show an increase on carbon dioxide over five years and annual variation driven by photosynthesis. This exercise enables students to practice basic quantitative skills and understand how important sampling intervals can be when studying changes over time. A goal is to see how small sample size may give incomplete picture of data.
Silver intercalated carbon nanotubes
NASA Astrophysics Data System (ADS)
Borowiak-Palen, E.; Ruemmeli, M. H.; Mendoza, E.; Henley, S. J.; Cox, D. C.; Poa, C. H. P.; Stolojan, V.; Gemming, T.; Pichler, T.; Silva, S. R. P.
The intercalation of metals within carbon nanotube structures has extended the potential applications of these materials to possible quantum memory elements as well as high density magnetic storage media. In our study we use methodologies based on wet chemistry and solid state physical (excimer laser) processes to incorporate silver nanoparticles in single and multiwall carbon nanotubes. We show high resolution TEM as evidence for the formation of very long ( ś 100-150 nm) silver quantum wires within SWCNT, and their properties are probed using various analytical techniques. The variation of the silver intercalated nanotube percentage and yield are compared for the SW- and MW-CNTs, when using wet chemistry versus physical processes.
Carbon Currency: The Credits and Debits of Carbon Emissions Trading
NSDL National Science Digital Library
NOVA Australia, an initiative of the Australian Academy of Science, posts new feature articles regularly. 2000 publications include "Carbon currency: the credits and debits of carbon emissions trading" (discussing carbon emissions trading and whether trading can limit the enhanced greenhouse effect).
Determination of carbonate carbon in geological materials by coulometric titration
Engleman, E.E.; Jackson, L.L.; Norton, D.R.
A coulometric titration is used for the determination of carbonate carbon in geological materials. Carbon dioxide is evolved from the sample by the addition of 2 M perchloric acid, with heating, and is determined by automated coulometric titration. The coulometric titration showed improved speed and precision with comparable accuracy to gravimetric and gasometric techniques. ?? 1985.
Australian carbon dust emission: a carbon accounting omission?
Technology Transfer Automated Retrieval System (TEKTRAN)
Erosion preferentially removes the finest carbon- and nutrient-rich soil fractions, and consequently its role may be significant within terrestrial carbon (C) cycles. However, the impacts of wind erosion on soil organic carbon redistribution are not considered in most SOC models, or within the Austr...
Carbon nanotube initiated formation of carbon nanoscrolls Zhao Zhang1
Li, Teng
graphene on a substrate, initiated by a carbon nanotube CNT . The rolling of graphene into a CNS, combining with the exceptional mechanical and electronic properties inherited from the basal graphene,6Carbon nanotube initiated formation of carbon nanoscrolls Zhao Zhang1 and Teng Li1,2,a 1 Department
NASA Astrophysics Data System (ADS)
Schmidt, M. W.
While most of the subducted H2O is recycled at shallow and subarc depths, carbon is less readily mobilized and susceptive to complex redox processes involving CO2 in solids, fluids and melts, elemental carbon, Fe- and Si- carbides, and methane. Here I review the various ways of recycling carbon during subduction and present a spectrum of possible reaction products in the mantle. Metamorphic reactions liberate <20% of the subducted CO2 to the subarc region (Connolly 2005, EPSL). Larger amounts might be mobilized through (sediment) melting. Although the wet pelite solidus is only shifted by 30-50 oC (at 3 GPa) with carbonates, the latter remain stable with melts that are saturated in a H2O+CO2-fluid. Complete dissolution of carbonates requires temperatures above any predicted subduction geotherm. Carbonated sediments yield CO2-rich phonolites to 5 GPa but carbonatites at higher pressures. The silicate melts become increasingly potassic with pressure, while the alkali-rich carbonatites have their highest K/Na at 8 GPa, slightly decreasing to 13 GPa and become sodic with the disappearance of residual cpx at ~16 GPa. What may happen when carbonated pelite derived melts migrate into the mantle is illustrated in Central Italy: in this case, it can be experimentally demonstrated that hybridization of ultrapotassic phonolitic melts with ~2 wt% H2O and ~6 wt% CO2 in the mantle results in the primitive parents of the ultrapotassic kamafugite suites which have ~43 wt% SiO2. Hence, despite a crustal isotopic signature of C, O, and Sr in these rocks, the CO2 of the Italian magmatism does not stem from assimilation in the crust but from melts derived from subducted marine carbonates mixed with pelagic clays and then reacted in the mantle. The migration of CO2-bearing fluids and melts into the mantle may lead to a redox-shock. Where high liquid/mantle ratios prevail, carbonatites rest in their oxidized form and may only freeze in relatively cold lithospheric keels where they form metasomatic zones prone to generate kimberlites in the context of a much later remelting event. Where the redox-capacity of the oxidized crust-derived material is subequal to the reduced mantle, iron carbides are to be expected. The eutectic in the Fe-Ni-C system is at lower temperatures than the mantle adiabat, leading to the distinct possibility that such zones entrained in global mantle convection will contain ~1% of eutectic Fe-C-melt. When the amount of subduction derived CO2 is small compared to the redox capacity of a metal bearing reduced mantle, diamond will form, but diamond itself is not truly reducing at high pressures. The most extreme reducing case leads to moissanite (found together with diamond), which isotopic signature implies involvement of organically derived carbon. Moissanite (SiC) only forms at fO2 <6-8 log units below iron-wustite and coexists with mantle silicates that have an XMg of 0.995-0.998. Our calculations show that a fluid or melt with a bulk, which is slightly more reduced than the CO2-H2O-tieline in C-O-H, may evolve to ultra-reduced residual C-H-rich fluids through removal of CO2 (through carbonate precipitation) followed by removal of H2O (through hydrous silicate formation). As SiC may only be in grain scale equilibrium with the mantle and requires a protracted fluid-fractionation, we propose that SiC is generally a low temperature phase formed from originally already reducing fluids involving organic carbon and hence subduction.
Calcium carbonate with magnesium overdose
The combination of calcium carbonate and magnesium is commonly found in antacids, which are medicines that provide heartburn relief. Calcium carbonate with magnesium overdose occurs when someone accidentally or ...
Irradiation Stability of Carbon NanotubesĀ
Aitkaliyeva, Assel
Ion irradiation of carbon nanotubes is a tool that can be used to achieve modification of the structure. Irradiation stability of carbon nanotubes was studied by ion and electron bombardment of the samples. Different ion ...
Sensor applications of carbon nanotubes
Rushfeldt, Scott I
A search of published research on sensing mechanisms of carbon nanotubes was performed to identify applications in which carbon nanotubes might improve on current sensor technologies, in either offering improved performance, ...
Dewatering Peat With Activated Carbon
NASA Technical Reports Server (NTRS)
Rohatgi, N. K.
Proposed process produces enough gas and carbon to sustain itself. In proposed process peat slurry is dewatered to approximately 40 percent moisture content by mixing slurry with activated carbon and filtering with solid/liquid separation techniques.
14 April 2001 tmospheric carbon dioxide
Teskey, Robert O.
emissions is through increased carbon sequestration into forests. In a large-scale assessment, Birdsey- ing carbon sequestration in southern forests. Carbon sequestration via southern pine forests may policy commitments. Keywords: carbon sequestration; southern pine forests ABSTRACT MEETING GLOBAL POLICY
Model-based estimation of the global carbon budget and its uncertainty from carbon dioxide and carbon isotope records
Jain, Atul K.
Model-based estimation of the global carbon budget and its uncertainty from carbon dioxide and the terrestrial biosphere based on carbon dioxide and carbon isotope records, and prior information on model of carbon dioxide and the resulting atmospheric concentration of carbon dioxide determined from the behavior
NASA Technical Reports Server (NTRS)
St. Clair, Terry L. (Inventor); Maudgal, Shubha (Inventor); Pratt, J. Richard (Inventor)
A novel series of polymers and copolymers based on a polyimide backbone with the incorporation of carbonate moieties along the backbone. The process for preparing these polymers and copolymers is also disclosed as is a novel series of dinitrodiphenyl carbonates and diaminodiphenyl carbonates. The novel polymers and copolymers exhibit high temperature capability and because of the carbonate unit, many exhibit a high degree of order and/or crystallinity.
NASA Technical Reports Server (NTRS)
St.clair, T. L. (inventor); Maudgal, S. (inventor); Pratt, J. R. (inventor)
A novel series of polymers and copolymers based on a polymide backbone with the incorporation of carbonate moieties along the backbone is presented. The preparation process for the polymers and copolymers is disclosed together with a novel series of dinitrodiphenyl carbonates and diaminodiphenyl carbonates. The novel polyners and copolymers exhibit high temperature capability and because of the carbonate unit, many exhibit a high degree of order and/or crystallinity.
Wettability alteration in carbonates
Dag C Standnes; Tor Austad
Fractured oil-wet carbonate reservoirs are often located at low temperatures and pressures, and the oil recovery by pure pressure depletion is usually low. The potential for improved oil recovery (IOR) is therefore very high. An IOR method is to change the wettability of the reservoir towards more water-wet conditions so that water can spontaneously imbibe into the matrix blocks and
NSDL National Science Digital Library
Doug (producer) Hamilton
This short video follows San Francisco inventor and engineer Saul Griffith as he determines his family's carbon footprint and develops a special cargo bike to further reduce his individual footprint. This video highlights innovation, creativity, and design as solutions to problems. The overall message is inspiring and proactive.
There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle, arising from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO, on natural eco...
NSDL National Science Digital Library
In this problem set, learners will analyze the Keeling Curve showing carbon dioxide concentration in the atmosphere since 1985 to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.
NASA Astrophysics Data System (ADS)
Datta, Supriyo
Carbon nanotube transistors (CNTFETs) with performance greatly exceeding silicon MOSFETs have recently been demonstrated. In order to explore potential applications of CNT technologies in future nanoelectronic systems, it is important to understand the device physics and evaluate the upper limit for the performance of CNTFETs. We will present a theoretical evaluation of ballistic CNTFET's using both (1) a detailed atomistic model and (2) a simple, phenomenological model. CNTFETs present the possibility of achieving both the ballistic and quantum capacitance limits, leading to several interesting effects. For example, the transconductance, gm, is identical to the channel conductance, GD, and quantized in units of 4e^2/h. An analysis of recent experiments indicates that present-day CNTFET's still operate well below their performance limit due to parasitic resistance and scattering. Possible approaches for improving the performance will be discussed. References: [1] Jing Guo, Supriyo Datta, and Mark Lundstrom, Markus Brink and Paul McEuen, Ali Javey, Hongjie Dai, Hyoungsub Kim, and Paul McIntyre,"Assessment of Silicon MOS and Carbon Nanotube FET Performance LimitsUsing a General Theory of Ballistic Transistors", to appear in IEDM Proceedings, 2002. [2] Jing Guo, Sebastien Goasguen, Mark Lundstrom, and Supriyo Datta, "Metal-insulator-semiconductor electrostatics of carbon nanotubes" Appl. Phys. Lett., 81, 1486 (2002). [3] Jing Guo, Mark Lundstrom, and Supriyo Datta, "Performance Projections for Ballistic Carbon Nanotube Field-Effect Transistors", Appl. Phys. Lett., 80, 3192 (2002).
This paper presents a compilation and summary of design criteria, performance, and cost data from 22 operating municipal and industrial granular activated carbon (GAC) installations that treat water and wastewater or process food and beverage products. Guidance for using this inf...
Robert A. Olson; Jack H. Parker
Measurements of the spatial, spectral, and temporal characteristics of the beam irradiance of a carbon arc solar simulator are reported. Pyroelectric radiometer measurements of total irradiance and spectroradiometer measurements of spectral irradiance are presented. The solar simulator spectral irradiance is compared with the ASTM standard AM 1.5 global solar spectral irradiance over a wavelength region of 300-2500 nm. The suitability
Carbon smackdown: wind warriors
Glen Dahlbacka of the Accelerator & Fusion Research Division and Ryan Wiser of the Environmental Energy Technologies Division are the speakers.
July 16. 2010 carbon smackdown summer lecture: learn how Berkeley Lab scientists are developing wind turbines to be used in an urban setting, as well as analyzing what it will take to increase the adoption of wind energy in the U.S.
Carbon smackdown: smart windows
Delia Milliron
August 3, 2010 Berkeley Lab talk: In the fourth of five Carbon Smackdown matches, Berkeley Lab researchers Delia Milliron of the Materials Sciences Division and Stephen Selkowitz of the Environmental Energy Technologies Division talk about their work on energy-saving smart windows.
Carbon smackdown: smart windows
Delia Milliron
August 3, 2010 Berkeley Lab talk: In the fourth of five Carbon Smackdown matches, Berkeley Lab researchers Delia Milliron of the Materials Sciences Division and Stephen Selkowitz of the Environmental Energy Technologies Division talk about their work on energy-saving smart windows.
Bench Remarks: Carbon Dioxide.
ERIC Educational Resources Information Center
Bent, Henry A.
Discusses the properties of carbon dioxide in its solid "dry ice" stage. Suggests several demonstrations and experiments that use dry ice to illustrate Avogadro's Law, Boyle's Law, Kinetic-Molecular Theory, and the effects of dry ice in basic solution, in limewater, and in acetone. (TW)
Appel, Aaron M.
Whether due to changes in policy or consumption of available fossil fuels, alternative sources of energy will be required, especially given the rising global energy demand. However, one of the main factors limiting the widespread utilization of renewable energy, such as wind, solar, wave or geothermal, is our ability to store energy. Storage of energy from carbon-neutral sources, such as electricity from solar or wind, can be accomplished through many routes. One approach is to store energy in the form of chemical bonds, as fuels. The conversion of low-energy compounds, such as water and carbon dioxide, to higher energy molecules, such as hydrogen or carbon-based fuels, enables the storage of carbon-neutral energy on a very large scale. The author╣s work in this area is supported by the US Department of Energy Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.
NSDL National Science Digital Library
Molly Malone
In this activity, learners place cards featuring biological structures in order by their relative size from largest to smallest. The cards feature structures ranging from the carbon atom (340 pm) to a skin cell (30 ?m) to a coffee bean (8 mm). This activity can also be used as a formative assessment or an anticipatory set.
Carbon cloth supported electrode
Lu, Wen-Tong P. (Upper St. Clair, PA); Ammon, Robert L. (Baldwin both of, PA)
A flow-by anode is disclosed made by preparing a liquid suspension of about to about 18% by weight solids, the solids comprising about 3.5 to about 8% of a powdered catalyst of platinum, palladium, palladium oxide, or mixtures thereof; about 60 to about 76% carbon powder (support) having a particle size less than about 20 m.mu.m and about 20 to about 33% of an inert binder having a particle size of less than about 500 m.mu.m. A sufficient amount of the suspension is poured over a carbon cloth to form a layer of solids about 0.01 to about 0.05 cm thick on the carbon cloth when the electrode is completed. A vacuum was applied to the opposite side of the carbon cloth to remove the liquid and the catalyst layer/cloth assembly is dried and compressed at about 10 to about 50 MPa's. The binder is then sintered in an inert atmosphere to complete the electrode. The electrode is used for the oxidation of sulfur dioxide in a sulfur based hybrid cycle for the decomposition of water.
Carbon star effective temperatures
S. T. Ridgway; G. H. Jacoby; R. R. Joyce; D. C. Wells
Possible methods for measuring the effective temperatures of individual carbon stars are discussed. Since calibrations of broad or narrow-band photometric colors is impractical at present, empirical corrections to narrow band color temperatures is the only valid procedure. The effective temperature of the star TW Oph is estimated, based on preliminary reduction of the occultation and associated photometry
3, 409447, 2006 Modeling carbon
Boyer, Edmond
impacts of management alternatives on soil carbon storage of farmland in Northwest China F. Zhang1,3 , CBGD 3, 409Ł447, 2006 Modeling carbon dynamics in farmland of China F. Zhang et al. Title Page Correspondence to: C. Li (firstname.lastname@example.com) 409 #12;BGD 3, 409Ł447, 2006 Modeling carbon dynamics
The Geostationary Carbon Process Mapper
Richard Key; Stanley Sander; Annmarie Eldering; Charles Miller; Christian Frankenberg; Vijay Natraj; David Rider; Jean-Francois Blavier; Dmitriy Bekker; Yen-Hung Wu
The Geostationary Carbon Process Mapper (GCPM) is an earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. The measurement strategy delivers a process based understanding of the carbon cycle that is accurate and extensible from city to regional and continental scales. This understanding comes from contiguous maps of carbon dioxide
Carbon Nanotube Linear Bearing Nanoswitches
Bockrath, Marc
Carbon Nanotube Linear Bearing Nanoswitches V. V. Deshpande, H.-Y. Chiu, H. W. Ch. Postma, C. Miko-friction bearing capabilities of multiwalled carbon nanotubes (MWNTs) to realize nanoelectromechanical switches bearing capabilities3-5 of multi- and double-walled carbon nanotubes (MWNTs and DWNTs) to realize
Full Carbon Account for Russia
S. Nilsson; A. Shvidenko; V. Stolbovoi; M. Gluck; M. Jonas; M. Obersteiner
The Forestry Project (FOR) at IIASA has produced a full carbon account (FCA) for Russia for 1990, together with scenarios for 2010. Currently, there are rather big question marks regarding the existing carbon accounts for Russia, and Russia is critical to the global carbon balance due to its size. IIASA is in a position to perform solid analysis of Russia
Carbon: electrochemical and physicochemical properties
K Kinoshita
This book provides a reference source for the application and study of carbon materials in electrochemistry. The first four chapters deal with the physical properties and chemical reactivity of carbon in its many forms. The remaining chapters focus on the role of carbon materials in electrode and electrochemistry applications. The book concludes with a complete listing of recently assigned patents
8, 73157337, 2008 Carbon dioxide
Paris-Sud XI, Universitķ de
ACPD 8, 7315Ł7337, 2008 Carbon dioxide distributions over Europe C. Gurk et al. Title Page Abstract distributions of carbon dioxide over Europe C. Gurk1 , H. Fischer1 , P. Hoor1 , M.G. Lawrence1 , J. Lelieveld1 Publications on behalf of the European Geosciences Union. 7315 #12;ACPD 8, 7315Ł7337, 2008 Carbon dioxide
Carbon sequestration research and development
Dave Reichle; John Houghton; Bob Kane; Jim Ekmann
Predictions of global energy use in the next century suggest a continued increase in carbon emissions and rising concentrations of carbon dioxide (COŌ) in the atmosphere unless major changes are made in the way we produce and use energy--in particular, how we manage carbon. For example, the Intergovernmental Panel on Climate Change (IPCC) predicts in its 1995 ''business as usual''
The nature of carbon in forests is discussed from the perspective of carbon sequestration and global climate change. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Areas vulnerable to climate change with respect to ca...
Carbon Fiber Risk Analysis. [conference
NASA Technical Reports Server (NTRS)
The scope and status of the effort to assess the risks associated with the accidental release of carbon/graphite fibers from civil aircraft is presented. Vulnerability of electrical and electronic equipment to carbon fibers, dispersal of carbon fibers, effectiveness of filtering systems, impact of fiber induced failures, and risk methodology are among the topics covered.
1, 311333, 2004 Carbon sources
Paris-Sud XI, Universitķ de
was evident from sedimentary total organic carbon (TOC) and 13 CTOC data. PLFA 13 C data indicate) and bulk organic carbon. Export of mangrove-derived organic matter to the adjacent5 seagrass-covered bayBGD 1, 311Ł333, 2004 Carbon sources supporting benthic mineralization S. Bouillon et al. Title Page
1, 393412, 2004 Carbon isotope
Boyer, Edmond
BGD 1, 393Ł412, 2004 Carbon isotope anomaly in the major plant C1 pool F. Keppler et al. Title Page Biogeosciences Discussions is the access reviewed discussion forum of Biogeosciences Carbon isotope email@example.com) 393 #12;BGD 1, 393Ł412, 2004 Carbon isotope anomaly in the major plant C1 pool F. Keppler et al. Title
Arnold Schwarzenegger THE CARBON DIOXIDE
i Arnold Schwarzenegger Governor THE CARBON DIOXIDE ABATEMENT POTENTIAL OF CALIFORNIA'S MID, Afzal Siddiqui, and Judy Lai. 2011. The Carbon Dioxide Abatement Potential of California's Mid/Agricultural/Water EndUse Energy Efficiency Ę Renewable Energy Technologies Ę Transportation The Carbon Dioxide
Homogeneous hydrogenation of carbon dioxide
Philip G. Jessop; Takao. Ikariya; Ryoji. Noyori
Carbon dioxide (COŌ) is of the greatest interest as a CŌü feedstock because of the vast amounts of carbon which exist in this form and because of the low cost of bulk COŌ. Currently, toxic carbon monoxide, the main competitor for many processes, is used in industry instead because COŌ is perceived to be less reactive and its efficient catalytic
Carbon Monoxide in the Atmosphere
R. C. Robbins; K. M. Borg; E. Robinson
A carbon monoxide analyzer has been developed which is capable of continuous measurement of the carbon monoxide concentration in the atmosphere. The operating principle of the instrument is the reaction of carbon monoxide with hot mercuric oxide followed by the photometric determination of the mercury vapor produced. Oxygenated hydrocarbons and olefins are quantitatively detected. Those normally present are in the
Boyer, Edmond
, suggested much larger estimates for tropical forest carbon sequestration in the Ama- zon BasinBGD 4, 99Ł123, 2007 Amazon carbon balanc J. Lloyd et al. Title Page Abstract Introduction Discussions is the access reviewed discussion forum of Biogeosciences An airborne regional carbon balance
Porous carbon EOS: numerical analysis
A. Aliverdiev; D. Batani; R. Dezulian; T. Vinci
In this paper, we address the problem of direct simulation of laser-driven shock experiments aiming at determining the equation of state (EOS) of carbon using the ōrelativeö impedance mismatch method. In particular, using tabulated carbon EOS (SESAME library, material number 7830), we have found some difficulties in reducing the initial density of the material in simulations with porous carbon. We
Wrigley, Stuart
and recycling, waste management, carbon capture and storage, addi- tional energy sources, alternative fuelsLOW CARBON & RENEWABLES #12;Ż570 million GVA THE SECTOR COMPRISES 326 COMPANIES EMPLOYING 12,240 PEOPLE, CONTRIBUTING Ż570 MILLION IN GVA. Across Sheffield City Region, the low carbon and renewable sec
Carbon aerosols and atmospheric photochemistry
D. J. Lary; A. M. Lee; R. Toumi; M. J. Newchurch; M. Pirre; J. B. Renard
Carbon aerosols are produced by all combustion processes. This paper investigates some possible effects of heterogeneous reduction of atmospheric constituents on carbon aerosols. Reduction of HNO3, NO2, and 03 on carbon aerosols may be an important effect of increased air traffic that has not been considered to date. It is shown that if HNO3, NO2 and 03 are heterogeneously reduced
Multifunctional Superhydrophobic Polymer/Carbon Nanocomposites: Graphene, Carbon Nanotubes, or Carbon Black?
Daraio, Chiara
and macro scales4 and textiles5 to name a few. Superhydrophobicity provides a pathway toward protect- ingMultifunctional Superhydrophobic Polymer/Carbon Nanocomposites: Graphene, Carbon Nanotubes, Switzerland *S Supporting Information ABSTRACT: Superhydrophobic surfaces resisting water penetration
Bioenergy, the Carbon Cycle, and Carbon Policy
NASA Astrophysics Data System (ADS)
Kammen, D. M.
The evolving energy and land-use policies across North America and Africa provide critical case studies in the relationship between regional development, the management of natural resources, and the carbon cycle. Over 50 EJ of the roughly 430 EJ total global anthropogenic energy budget is currently utilized in the form of direct biomass combustion. In North America 3 - 4 percent of total energy is derived from biomass, largely in combined heat and power (CHP) combustion applications. By contrast Africa, which is a major consumer of 'traditional' forms of biomass, uses far more total bioenergy products, but largely in smaller batches, with quantities of 0.5 - 2 tons/capita at the household level. Several African nations rely on biomass for well over 90 percent of household energy, and in some nations major portions of the industrial energy supply is also derived from biomass. In much of sub-Saharan Africa the direct combustion of biomass in rural areas is exceeded by the conversion of wood to charcoal for transport to the cities for household use there. There are major health, and environmental repercussions of these energy flows. The African, as well as Latin American and Asian charcoal trade has a noticeable signature on the global greenhouse gas cycles. In North America, and notably Scandinavia and India as well, biomass energy and emerging conversion technologies are being actively researched, and provide tremendous opportunities for the evolution of a sustainable, locally based, energy economy for many nations. This talk will examine aspects of these current energy and carbon flows, and the potential that gassification and new silvicultural practices hold for clean energy systems in the 21st century. North America and Africa will be examined in particular as both sources of innovation in this field, and areas with specific promise for application of these energy technologies and biomass/land use practices to further energy and global climate management.
Carbon Sequestration and Its Role in the Global Carbon Cycle
NASA Astrophysics Data System (ADS)
McPherson, Brian J.; Sundquist, Eric T.
For carbon sequestration the issues of monitoring, risk assessment, and verification of carbon content and storage efficacy are perhaps the most uncertain. Yet these issues are also the most critical challenges facing the broader context of carbon sequestration as a means for addressing climate change. In response to these challenges, Carbon Sequestration and Its Role in the Global Carbon Cycle presents current perspectives and research that combine five major areas: Ģ The global carbon cycle and verification and assessment of global carbon sources and sinks Ģ Potential capacity and temporal/spatial scales of terrestrial, oceanic, and geologic carbon storage Ģ Assessing risks and benefits associated with terrestrial, oceanic, and geologic carbon storage Ģ Predicting, monitoring, and verifying effectiveness of different forms of carbon storage Ģ Suggested new CO2 sequestration research and management paradigms for the future. The volume is based on a Chapman Conference and will appeal to the rapidly growing group of scientists and engineers examining methods for deliberate carbon sequestration through storage in plants, soils, the oceans, and geological repositories.
Carbon sequestration and its role in the global carbon cycle
McPherson, Brian J.; Sundquist, Eric T.
For carbon sequestration the issues of monitoring, risk assessment, and verification of carbon content and storage efficacy are perhaps the most uncertain. Yet these issues are also the most critical challenges facing the broader context of carbon sequestration as a means for addressing climate change. In response to these challenges, Carbon Sequestration and Its Role in the Global Carbon Cycle presents current perspectives and research that combine five major areas: Ģ The global carbon cycle and verification and assessment of global carbon sources and sinks Ģ Potential capacity and temporal/spatial scales of terrestrial, oceanic, and geologic carbon storage Ģ Assessing risks and benefits associated with terrestrial, oceanic, and geologic carbon storage Ģ Predicting, monitoring, and verifying effectiveness of different forms of carbon storage Ģ Suggested new CO2 sequestration research and management paradigms for the future. The volume is based on a Chapman Conference and will appeal to the rapidly growing group of scientists and engineers examining methods for deliberate carbon sequestration through storage in plants, soils, the oceans, and geological repositories.
Carbon Sequestered, Carbon Displaced and the Kyoto Context
Marland, G.; Schlamadinger, B.
The integrated system that embraces forest management, forest products, and land-use change impacts the global carbon cycle - and hence the net emission of the greenhouse gas carbon dioxide - in four fundamental ways. Carbon is stored in living and dead biomass, carbon is stored in wood products and landfills, forest products substitute in the market place for products made from other materials, and forest harvests can be used wholly or partially to displace fossil fuels in the energy sector. Implementation of the Kyoto Protocol to the United Nations Framework Convention on Climate Change would result in the creation of international markets for carbon dioxide emissions credits, but the current Kyoto text does not treat all carbon identically. We have developed a carbon accounting model, GORCAM, to examine a variety of scenarios for land management and the production of forest products. In this paper we explore, for two simple scenarios of forest management, the carbon flows that occur and how these might be accounted for under the Kyoto text. The Kyoto protocol raises questions about what activities can result in emissions credits, which carbon reservoirs will be counted, who will receive the credits, and how much credit will be available? The Kyoto Protocol would sometimes give credits for carbon sequestered, but it would always give credits when fossil-fuel carbon dioxide emissions are displaced.
Erosion of soil organic carbon: implications for carbon sequestration
Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.
Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.
Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel Complexes
Jones, William D.
Catalytic Carbon-Carbon and Carbon-Silicon Bond Activation and Functionalization by Nickel of Rochester, Rochester, New York 14627 Received June 11, 1999 The nickel alkyne complexes (dippe)Ni(Me3Si, and nickel phosphine complexes.3 Milstein and co-workers reported the cata- lytic hydrogenolysis
Carbon Capture and Storage, 2008
The U.S. Department of Energy is researching the safe implementation of a technology called carbon sequestration, also known as carbon capture and storage, or CCS. Based on an oilfield practice, this approach stores carbon dioxide, or CO2 generated from human activities for millennia as a means to mitigate global climate change. In 2003, the Department of Energys National Energy Technology Laboratory formed seven Regional Carbon Sequestration Partnerships to assess geologic formations suitable for storage and to determine the best approaches to implement carbon sequestration in each region. This video describes the work of these partnerships.
Understanding the Global Carbon Cycle
NSDL National Science Digital Library
The site offers charts and graphs to aid in a detailed explanation of where carbon comes from and where it goes. Supplementing the main topic, links lead to the topics Carbon and Land Use, Missing Carbon Sink, and Forest Sequestered Carbon Dioxide. Their conclusion is that the major contributor to climatic change, and hence the human activity most in need of change, is use of fossil fuels for energy. Advances in the technology of renewable energy sources, including wood-derived fuels, might reduce our reliance on fossil fuels and thus reduce global emissions of carbon dioxide significantly.
Carbon dioxide dangers demonstration model
Venezky, Dina; Wessells, Stephen
Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.
Carbon sequestration by switchgrass
NASA Astrophysics Data System (ADS)
Ma, Zhiqin
Increasing levels of carbon dioxide (CO2), which is partly due to use of fossil fuel, is primarily responsible for global climate warming. Producing and using switchgrass for bioenergy can help reduce atmospheric CO2 buildup by partly replacing use of fossil fuels and by carbon (C) sequestration. Switchgrass (Panicum virgatum L) is a potential bioenergy crop suited to the southeastern U.S. The objective of this study was to determine the effects of agricultural management practices on C sequestration by switchgrass. Field experiments were designed so that differences in row spacing, nitrogen (N) rate, switchgrass cultivar, harvest frequency, and soil type on C sequestration would be evaluated. Soil C dynamic studies indicated that soil C mineralization, microbial biomass C, and C turnover tended to increase with time after switchgrass establishment in Norfolk sandy sod. These changes were more apparent in 0 to 15 cm than 15 to 30 cm of the sandy loam soil. Ten years of continuous switchgrass resulted in higher soil C level than nearby fallow soils, but several years of continuous grass may be need before increases are measurable. Results from this study imply that management practices can impact soil C sequestration with switchgrass, such as several years for humification by conversion of the root accumulation to the stable soil C pool. The effect of N was to increase N but not C concentration of roots, which imply that any increases in C sequestration by switchgrass would be due to increases in root biomass. Switchgrass roots were more dense in Pacolet clay soil than the other soils used in this study. Carbon storage in switchgrass, shoots increased as row width and N rate increased. Carbon storage in shoots and roots generally increased with time after switchgrass establishment, and rate of increase of C storage in root was higher than that in shoot. Carbon partitioning analyses showed that C storage was soil C > root C > shoot C. The root/shoot ratio of C storage was 2.2, and this implied that C partitioning to roots plays a key role in C sequestration by switchgrass. Carbon storage in the overall switchgrass-soil system showed an upward trend after switchgrass establishment.
Oxidation of Carbon/Carbon through Coating Cracks
NASA Technical Reports Server (NTRS)
Jacobson, N. S.; Roth, d. J.; Rauser, R. W.; Cawley, J. D.; Curry, D. M.
Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonab
Quantitative analysis of carbon in silicon carbide coated with carbon.
Lee, Hongrim; Kim, Junsu; Yun, Jondo
Nonconductive specimens for scanning electron microscopy or X-ray microanalysis are coated with conductive carbon in order to reduce charging. But carbon film absorbs X-ray fluxes causing errors in measuring chemical composition. Especially when the carbon content is measured, carbon coating not only blocks X-rays but also becomes a source of carbon X-rays. It is thus necessary to determine how much errors are induced by carbon coating, and how thick coating is allowed for the accurate measurement. In this study, quantitative analysis of carbon on silicon carbide with carbon coating films was attempted by electron probe microanalyzer. It was found that measured carbon content increased in a nonlinear manner up to 40% with a film thickness, whereas silicon content decreased slightly. Carbon X-ray intensity was determined by computer simulation, which increased in a linear manner with the thickness. The discrepancy was due to a nucleation and growth of islands and thus a change of density with a thickening of coating film. PMID:23920162
Carbon K-edge Spectra of Carbonate Minerals
Brandes, J.; Wirick, S; Jacobsen, C
Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.
A carbon sink pathway increases carbon productivity in cyanobacteria.
Oliver, John W K; Atsumi, Shota
The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity. PMID:25777135
NASA Technical Reports Server (NTRS)
HyComp(R), Inc. development a line of high temperature carbon fiber composite products to solve wear problems in the harsh environment of steel and aluminum mills. WearComp(R), self-lubricating composite wear liners and bushings, combines carbon graphite fibers with a polyimide binder. The binder, in conjunction with the fibers, provides the slippery surface, one that demands no lubrication, yet wears at a very slow rate. WearComp(R) typically lasts six to ten times longer than aluminum bronze. Unlike bronze, WearComp polishes the same surface and imparts a self-lube film for years of service. It is designed for continuous operation at temperatures of 550 degrees Fahrenheit and can operate under high compressive loads.
NASA Technical Reports Server (NTRS)
2005-01-0123 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of some of the widely-varied terrain of the martian south polar residual cap. The landforms here are composed mainly of frozen carbon dioxide. Each year since MGS arrived in 1997, the scarps that bound each butte and mesa, or line the edges of each pit, in the south polar region, have changed a little bit as carbon dioxide is sublimed away. The scarps retreat at a rate of about 3 meters (3 yards) per martian year. Most of the change occurs during each southern summer. Location near: 86.7oS, 9.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring
NSDL National Science Digital Library
Roberta Johnson
Carbon Cycle of Mars is a Windows to the Universe Exploratour and provides information and images about carbon dioxide and the lower atmosphere of Mars. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate, and advanced options for each topic level.
Carbon Monoxide Targeting Mitochondria
Queiroga, Clßudia S. F.; Almeida, Ana S.; Vieira, Helena L. A.
Mitochondria present two key roles on cellular functioning: (i) cell metabolism, being the main cellular source of energy and (ii) modulation of cell death, by mitochondrial membrane permeabilization. Carbon monoxide (CO) is an endogenously produced gaseoustransmitter, which presents several biological functions and is involved in maintaining cell homeostasis and cytoprotection. Herein, mitochondrion is approached as the main cellular target of carbon monoxide (CO). In this paper, two main perspectives concerning CO modulation of mitochondrial functioning are evaluated. First, the role of CO on cellular metabolism, in particular oxidative phosphorylation, is discussed, namely, on: cytochrome c oxidase activity, mitochondrial respiration, oxygen consumption, mitochondrial biogenesis, and general cellular energetic status. Second, the mitochondrial pathways involved in cell death inhibition by CO are assessed, in particular the control of mitochondrial membrane permeabilization. PMID:22536507
Depositing Diamondlike Carbon Films
NASA Technical Reports Server (NTRS)
Mirtich, M. J.; Sovey, J. S.; Banks, B. A.
New process demonstrated to make thin films (usually thousands of angstroms to few microns thick) that have properties of diamonds. Various plasma and ion-beam techniques employed to generate films. Films made by radio-frequency plasma decomposition of hydrocarbon gas or other alkanes, by low-energy carbon-ion-beam deposition, or by ion plating and dual ion technique using carbon target. Advantages of new process over others are films produced, though amorphous, are clear, extremely hard, chemically inert, of high resistivity, and have index of refraction of 3.2 properties similar to those of single-crystal diamonds. Films have possible uses in microelectronic applications, high-energy-laser and plastic windows, corrosion protection for metals, and other applications where desired properties of film shaped during the film-formation process.
Plasticity of amorphous carbon
NASA Astrophysics Data System (ADS)
von Lautz, Julian; Moseler, Michael; Pastewka, Lars
We use molecular dynamics simulations to probe the plastic response of representative bulk volumes of amorphous carbon at densities from 2.0 g cm-3 to 3.3 g cm-3 in simple and triaxial shear. After an initial elastic response the samples yield with only little strain hardening or softening. Individual plastic events in this network forming glass are strikingly similar to those observed for bulk metallic glasses: We find that plasticity is carried by fundamental rearrangements of regions of around 100 atoms, the shear transformation zone. In the simple shear geometry, those events coalesce to form a shear-band on longer time scales. During plastic deformation, the material changes its hybridization by transforming sp3 carbon atoms to sp2. We provide evidence that this transformation of the structural state occurs before the material yields, hence weakening the material. This work was supported by the European Commission (Marie-Curie IOF 272619).
Olson, R A; Parker, J H
Measurements of the spatial, spectral, and temporal characteristics of the beam irradiance of a carbon arc solar simulator are reported. Pyroelectric radiometer measurements of total irradiance and spectroradiometer measurements of spectral irradiance are presented. The solar simulator spectral irradiance is compared with the ASTM standard AM 1.5 global solar spectral irradiance over a wavelength region of 300-2500 nm. The suitability of the solar simulator for laser receiver testing is discussed. PMID:20582141
NASA Astrophysics Data System (ADS)
Olson, Robert A.; Parker, Jack H.
Measurements of the spatial, spectral, and temporal characteristics of the beam irradiance of a carbon arc solar simulator are reported. Pyroelectric radiometer measurements of total irradiance and spectroradiometer measurements of spectral irradiance are presented. The solar simulator spectral irradiance is compared with the ASTM standard AM 1.5 global solar spectral irradiance over a wavelength region of 300-2500 nm. The suitability of the solar simulator for laser receiver testing is discussed.
Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.
Carbon nanotube network varactor
NASA Astrophysics Data System (ADS)
Generalov, A. A.; Anoshkin, I. V.; Erdmanis, M.; Lioubtchenko, D. V.; Ovchinnikov, V.; Nasibulin, A. G.; Rõisõnen, A. V.
Microelectromechanical system (MEMS) varactors based on a freestanding layer of single-walled carbon nanotube (SWCNT) films were designed, fabricated and tested. The freestanding SWCNT film was employed as a movable upper patch in the parallel plate capacitor of the MEMS. The measurements of the SWCNT varactors show very high tunability, nearly 100%, of the capacitance with a low actuation voltage of 10 V. The functionality of the varactor is improved by implementing a flexible nanocellulose aerogel filling.
Carbon nanotube network varactor.
Generalov, A A; Anoshkin, I V; Erdmanis, M; Lioubtchenko, D V; Ovchinnikov, V; Nasibulin, A G; Rõisõnen, A V
Microelectromechanical system (MEMS) varactors based on a freestanding layer of single-walled carbon nanotube (SWCNT) films were designed, fabricated and tested. The freestanding SWCNT film was employed as a movable upper patch in the parallel plate capacitor of the MEMS. The measurements of the SWCNT varactors show very high tunability, nearly 100%, of the capacitance with a low actuation voltage of 10 V. The functionality of the varactor is improved by implementing a flexible nanocellulose aerogel filling. PMID:25556375
Gregg Marland; Ralph M. Rotty
During the years 1975¢1978 concern over the increase of CO2 in the atmosphere expanded from the laboratory into the public policy arena. This was a period during which a profusion of international symposia, technical papers, and public-policy-oriented discussions drew wide attention to the potential dangers of unchecked growth of atmospheric CO2 and man's alterations of the global carbon cycle. At
Carbon nanotube plane fastener
NASA Astrophysics Data System (ADS)
Hirahara, Kaori; Ajioka, Shoichi; Nakayama, Yoshikazu
We report a feature of carbon nanotubes (CNTs) that arises when the surfaces of two vertically-aligned CNT brushes are pressed together. Adhesion between the CNTs creates a plane fastener-like device. Observations from scanning electron microscopy and measurements of adhesion properties indicate a device-dependence on CNT density and shape near the tip region. Among other applications, such fasteners have the potential to attach small components onto micron-sized electronic devices.
Richard G. Godec; Paul P. Kosenka; Brian D. Smith; Richard S. Hutte; Johanna V. Webb; Richard L. Sauer
The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The
Thermal Cycling of Thermal Control Paints on Carbon-Carbon and Carbon-Polyimide Composites
NASA Technical Reports Server (NTRS)
Jaworske, Donald A.
Carbon-carbon composites and carbon-polyimide composites are being considered for space radiator applications owing to their light weight and high thermal conductivity. For those radiator applications where sunlight will impinge on the surface, it will be necessary to apply a white thermal control paint to minimize solar absorptance and enhance infrared emittance. Several currently available white thermal control paints were applied to candidate carbon-carbon and carbon-polyimide composites and were subjected to vacuum thermal cycling in the range of -100 C to +277 C. The optical properties of solar absorptance and infrared emittance were evaluated before and after thermal cycling. In addition, adhesion of the paints was evaluated utilizing a tape test. The test matrix included three composites: resin-derived carbon-carbon and vapor infiltrated carbon-carbon, both reinforced with pitch-based P-120 graphite fibers, and a polyimide composite reinforced with T-650 carbon fibers, and three commercially available white thermal control paints: AZ-93, Z-93-C55, and YB-71P.
Carbon Structure Hazard Control
NASA Technical Reports Server (NTRS)
Yoder, Tommy; Greene, Ben; Porter, Alan
Carbon composite structures are widely used in virtually all advanced technology industries for a multitude of applications. The high strength-to-weight ratio and resistance to aggressive service environments make them highly desirable. Automotive, aerospace, and petroleum industries extensively use, and will continue to use, this enabling technology. As a result of this broad range of use, field and test personnel are increasingly exposed to hazards associated with these structures. No single published document exists to address the hazards and make recommendations for the hazard controls required for the different exposure possibilities from damaged structures including airborne fibers, fly, and dust. The potential for personnel exposure varies depending on the application or manipulation of the structure. The effect of exposure to carbon hazards is not limited to personnel, protection of electronics and mechanical equipment must be considered as well. The various exposure opportunities defined in this document include pre-manufacturing fly and dust, the cured structure, manufacturing/machining, post-event cleanup, and post-event test and/or evaluation. Hazard control is defined as it is applicable or applied for the specific exposure opportunity. The carbon exposure hazard includes fly, dust, fiber (cured/uncured), and matrix vapor/thermal decomposition products. By using the recommendations in this document, a high level of confidence can be assured for the protection of personnel and equipment.
Interfaces of propylene carbonate
NASA Astrophysics Data System (ADS)
You, Xinli; Chaudhari, Mangesh I.; Pratt, Lawrence R.; Pesika, Noshir; Aritakula, Kalika M.; Rick, Steven W.
Propylene carbonate (PC) wets graphite with a contact angle of 31░ at ambient conditions. Molecular dynamics simulations agree with this contact angle after 40% reduction of the strength of graphite-C atom Lennard-Jones interactions with the solvent, relative to the models used initially. A simulated nano-scale PC droplet on graphite displays a pronounced layering tendency and an Aztex pyramid structure for the droplet. Extrapolation of the computed tensions of PC liquid-vapor interface estimates the critical temperature of PC accurately to about 3%. PC molecules lie flat on the PC liquid-vapor surface and tend to project the propyl carbon toward the vapor phase. For close PC neighbors in liquid PC, an important packing motif stacks carbonate planes with the outer oxygen of one molecule snuggled into the positively charged propyl end of another molecule so that neighboring molecule dipole moments are approximately antiparallel. The calculated thermal expansion coefficient and the dielectric constants for liquid PC agree well with experiment. The distribution of PC molecule binding energies is closely Gaussian. Evaluation of the density of the coexisting vapor then permits estimation of the packing contribution to the PC chemical potential and that contribution is about two thirds of the magnitude of the contributions due to attractive interactions, with opposite sign.
Interfaces of propylene carbonate.
You, Xinli; Chaudhari, Mangesh I; Pratt, Lawrence R; Pesika, Noshir; Aritakula, Kalika M; Rick, Steven W
Propylene carbonate (PC) wets graphite with a contact angle of 31░ at ambient conditions. Molecular dynamics simulations agree with this contact angle after 40% reduction of the strength of graphite-C atom Lennard-Jones interactions with the solvent, relative to the models used initially. A simulated nano-scale PC droplet on graphite displays a pronounced layering tendency and an Aztex pyramid structure for the droplet. Extrapolation of the computed tensions of PC liquid-vapor interface estimates the critical temperature of PC accurately to about 3%. PC molecules lie flat on the PC liquid-vapor surface and tend to project the propyl carbon toward the vapor phase. For close PC neighbors in liquid PC, an important packing motif stacks carbonate planes with the outer oxygen of one molecule snuggled into the positively charged propyl end of another molecule so that neighboring molecule dipole moments are approximately antiparallel. The calculated thermal expansion coefficient and the dielectric constants for liquid PC agree well with experiment. The distribution of PC molecule binding energies is closely Gaussian. Evaluation of the density of the coexisting vapor then permits estimation of the packing contribution to the PC chemical potential and that contribution is about two thirds of the magnitude of the contributions due to attractive interactions, with opposite sign. PMID:23534654
Carbon in primitive meteorites
NASA Technical Reports Server (NTRS)
Kerridge, John F.
No meteorites are truly primitive, in the sense of being pristine collections of interstellar grains or solar-nebular condensates. Nonetheless, some chrondritic meteorites have been so little altered by secondary processing that they are commonly termed primitive and it is almost a definition of such chondrites that they contain significant quantities of carbon. Most of that carbon is of apparently local, i.e., solar-system, origin but a proportion that ranges from trace, in some cases, to minor, in others, is believed to be exotic, i.e., of circumstellar or interstellar origin, and it is upon such material that researchers focus here. The nature of the meteoritic samples and the techniques used to analyse them are briefly discussed and the observational record is surveyed. Clearly, the study of exotic carbon preserved in meteorites has been informative about sites of nucleosynthesis, processes of nucleation and growth of grains in stellar outflows, grain survival in the interstellar medium, and many other topics of astrophysical significance. Much more work, particularly of an interdisciplinary nature remains to be done, however.
Carbon-14 Graphitization Chemistry
NASA Astrophysics Data System (ADS)
Miller, James; Collon, Philippe; Laverne, Jay
Accelerator Mass Spectrometry (AMS) is a process that allows for the analysis of mass of certain materials. It is a powerful process because it results in the ability to separate rare isotopes with very low abundances from a large background, which was previously impossible. Another advantage of AMS is that it only requires very small amounts of material for measurements. An important application of this process is radiocarbon dating because the rare 14C isotopes can be separated from the stable 14N background that is 10 to 13 orders of magnitude larger, and only small amounts of the old and fragile organic samples are necessary for measurement. Our group focuses on this radiocarbon dating through AMS. When performing AMS, the sample needs to be loaded into a cathode at the back of an ion source in order to produce a beam from the material to be analyzed. For carbon samples, the material must first be converted into graphite in order to be loaded into the cathode. My role in the group is to convert the organic substances into graphite. In order to graphitize the samples, a sample is first combusted to form carbon dioxide gas and then purified and reduced into the graphite form. After a couple weeks of research and with the help of various Physics professors, I developed a plan and began to construct the setup necessary to perform the graphitization. Once the apparatus is fully completed, the carbon samples will be graphitized and loaded into the AMS machine for analysis.
Oxidative Attack of Carbon/Carbon Substrates through Coating Pinholes
NASA Technical Reports Server (NTRS)
Jacobson, Nathan S.; Leonhardt, Todd; Curry, Donald; Rapp, Robert A.
A critical issue with oxidation protected carbon/carbon composites used for spacecraft thermal protection is the formation of coating pinholes. In laboratory experiments, artificial pinholes were drilled through SiC-coatings on a carbon/carbon material and the material was oxidized at 600, 1000, and 1400 C at reduced pressures of air. The attack of the carbon/carbon was quantified by both weight loss and a novel cross-sectioning technique. A two-zone, one dimensional diffusion control model was adapted to analyze this problem. Agreement of the model with experiment was reasonable at 1000 and 1400 C; however results at lower temperatures show clear deviations from the theory suggesting that surface reaction control plays a role.
(abstract) Unidirectional Carbon/Carbon for Ion Engine Optics
NASA Technical Reports Server (NTRS)
Brown, D. Kyle
Conventional ion engine optical grids are made from hydroformed molybdenum. Carbon/carbon has been utilized in place of molybdenum because of its lower sputter yield, which contributes a greatly increased engine life, and for its low cte, which allows more efficient engine operation. The requirements for this material are that it must have high stiffness, very tight dimensional tolerances, and can be optimized for an hexagonal hole pattern with a very high open area friction. The carbon/carbon for this application was fabricated from unidirectional tape prepreg, using pitch fiber, and was processed to a very high temperature. The use of unidirectional tape allowed for a sufficient number of plies to be used to generate a balanced three directional layup within the thickness constraints of the material, as well as providing strength and stiffness over that normally seen with fabric based carbon/carbons.
Reconciling biodiversity and carbon conservation.
Thomas, Chris D; Anderson, Barbara J; Moilanen, Atte; Eigenbrod, Felix; Heinemeyer, Andreas; Quaife, Tristan; Roy, David B; Gillings, Simon; Armsworth, Paul R; Gaston, Kevin J
Climate change is leading to the development of land-based mitigation and adaptation strategies that are likely to have substantial impacts on global biodiversity. Of these, approaches to maintain carbon within existing natural ecosystems could have particularly large benefits for biodiversity. However, the geographical distributions of terrestrial carbon stocks and biodiversity differ. Using conservation planning analyses for the New World and Britain, we conclude that a carbon-only strategy would not be effective at conserving biodiversity, as have previous studies. Nonetheless, we find that a combined carbon-biodiversity strategy could simultaneously protect 90% of carbon stocks (relative to a carbon-only conservation strategy) and > 90% of the biodiversity (relative to a biodiversity-only strategy) in both regions. This combined approach encapsulates the principle of complementarity, whereby locations that contain different sets of species are prioritised, and hence disproportionately safeguard localised species that are not protected effectively by carbon-only strategies. It is efficient because localised species are concentrated into small parts of the terrestrial land surface, whereas carbon is somewhat more evenly distributed; and carbon stocks protected in one location are equivalent to those protected elsewhere. Efficient compromises can only be achieved when biodiversity and carbon are incorporated together within a spatial planning process. PMID:23279784
Carbon-hydrogen bonding in near-frictionless carbon.
Johnson, J. A.; Woodford, J. B.; Rajput, D.; Kolesnikov, A. I.; Schleuter, J. A.; Eryilmaz, O. L.; Erdemir, A.; Univ. of Tennessee Space Inst.; ORNL
The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp{sup 3}-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.
Carbon-hydrogen bonding in near-frictionless carbon
NASA Astrophysics Data System (ADS)
Johnson, J. A.; Woodford, J. B.; Rajput, D.; Kolesnikov, A. I.; Schleuter, J. A.; Eryilmaz, O. L.; Erdemir, A.
The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp3-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.
Carbon-hydrogen bonding in near-frictionless carbon
Johnson, Jackie A. [University of Tennessee Space Institute; Woodford, John B [Argonne National Laboratory (ANL); Rajput, Deepak [University of Tennessee Space Institute; Kolesnikov, Alexander I [ORNL; Schleuter, John A [Argonne National Laboratory (ANL); Eryilmaz, Osman L [Argonne National Laboratory (ANL); Erdemir, Ali [Argonne National Laboratory (ANL)
The uniquely low friction behavior of near frictionless carbon (NFC) as compared to conventional diamond-like carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier Transform Infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp3-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.
Geologic Carbon Sequestration and Biosequestration (Carbon Cycle 2.0)
DePaolo, Don [Director, LBNL Earth Sciences Division
Don DePaolo, Director of LBNL's Earth Sciences Division, speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/
Soil warming, carbon-nitrogen interactions, and forest carbon budgets.
Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim
Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system. PMID:21606374
Terrestrial carbon histories: Implications for future global carbon cycle dynamics
Solomon, A.M.; Webb. T.; Prentice, I.C. (Environmental Protection Agency, Corvallis (United States) Brown Univ., Providence, RI (United States) Univ. of Lund (Sweden))
One of the most recalcitrant scientific questions during the past 20 years of research on increasing atmospheric CO[sub 2] is whether (and how much) the earth is a net source or a net sink for carbon now, and, whether (and how much) it will be so in the future. The answer is critical to cleaning international response strategies as well as to predicting biospheric futures with or without effects of political action. Here, we examine the potential value of information available in paleoecological data for defining the role of the terrestrial biosphere in global carbon cycle variations. The data describe histories of carbon in the atmosphere (primarily from stratigrapheric CO[sub 2] concentrations embedded in polar ice caps), above-ground biomass (primarily vegetation reconstructed from fossil pollen data in lacustrine sediments) and soil carbon pools (primarily from soil carbon inventories and landscape histories). After discussing the implications of inferences on the nature of global carbon cycling which are directly obtainable from the data, we evaluate the paleoecological information for formulating and testing predictive models written to describe future carbon cycle dynamics. Finally, we apply one such model to project future dynamics of the terrestrial carbon cycle, and use the obvious uncertainties in the results to define the paleoecological research agenda required for definitive solution of the carbon sequestration question.
Carbon Nanotube-Enhanced Carbon-Phenenolic Ablator Material
NASA Technical Reports Server (NTRS)
Kikolaev, P.; Stackpoole, M.; Fan, W.; Cruden, B. A.; Waid, M.; Moloney, P.; Arepalli, S.; Arnold, J.; Partridge, H.; Yowell, L.
This viewgraph presentation reviews the use of PICA (phenolic impregnated carbon ablator) as the selected material for heat shielding for future earth return vehicles. It briefly reviews the manufacturing of PICA and the advantages for the use of heat shielding, and then explains the reason for using Carbon Nanotubes to improve strength of phenolic resin that binds carbon fibers together. It reviews the work being done to create a carbon nanotube enhanced PICA. Also shown are various micrographic images of the various PICA materials.
Carbon-Carbon Turbocharger Housing Unit for Intermittent Combustion Engines
NASA Technical Reports Server (NTRS)
Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)
An improved, lightweight, turbine housing unit for an intermittent combustion reciprocating internal combustion engine turbocharger is prepared from a lay-up or molding of carbon-carbon composite materials in a single-piece or two-piece process. When compared to conventional steel or cast iron, the use of carbon-carbon composite materials in a turbine housing unit reduces the overall weight of the engine and reduces the heat energy loss used in the turbocharging process. This reduction in heat energy loss and weight reduction provides for more efficient engine operation.
Development of improved coating for advanced carbon-carbon components
NASA Technical Reports Server (NTRS)
Yamaki, Y. R.; Brown, J. J.
Reaction sintered silicon nitride (RSSN) was studied as a substitute coating material on the carbon-carbon material (RCC) presently used as a heat shield on the space shuttle, and on advanced carbon-carbon (ACC), a later development. On RCC, RSSN showed potential in a 538 C (1000 F) screening test in which silicon carbide coated material exhibits its highest oxidation rate; RSSN afforded less protection to ACC because of a larger thermal expansion mismatch. Organosilicon densification and metallic silicon sealing methods were studied as means of further increasing the oxidation resistance of the coating, and some improvement was noted when these methods were employed.
Morphological and luminescent studies on nanosized Er, Yb¢Yttrium oxide up-converter prepared from different precursors
Ana Maria Pires; Osvaldo Antonio Serra; Marian Rosaly Davolos
In this paper, we report luminescent and morphological studies with yttrium oxide samples doped with ytterbium and erbium. The samples were prepared by the combustion method and also from different precursors: oxalate, basic carbonate and polymeric resin. All powders were identified as being an yttrium oxide with a C-form structure, independent of the employed precursor. From mean crystallite size measurements,
Carbon-Hydrogen and Carbon-Carbon Bond Activation of Cyclopropane by a Hydridotris(pyrazolyl)borate
Jones, William D.
Carbon-Hydrogen and Carbon-Carbon Bond Activation of Cyclopropane by a Hydridotris and re-forming alkanes via carbon-carbon bond activation using heterogeneous catalysts is an important results in C-H activation of the hydrocarbon. The cyclopropyl hydride complex rearranges in benzene
Paasch, R.A.
A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys.
Understanding the global carbon cycle
Douglas, J.
Efforts to mitigate possible climate change due to rising atmospheric concentrations of greenhouse gases focus mostly on manipulation of the global carbon cycle - the movement and storage of carbon among the world`s oceans, atmosphere, and terrestrial systems. But predicting the likely effectiveness of various strategies to ameliorate global warming requires careful modeling of the complex processes that drive carbon cycling and determine atmospheric levels of carbon dioxide, and some of these processes are still not well understood. A new EPRI microcomputer model called GLOCO simulates many of the processes and can be used to perform quick {open_quotes}what if{close_quotes} strategy analyses. In addition, ongoing field studies are providing important new insights into the uptake of atmospheric carbon by forest and grassland ecosystems. Efforts are also under way to develop a much more complex computer program that can model the global carbon cycle with reference to specific geographic patterns. These efforts are discussed.
Conservation tillage for carbon sequestration
R. Lal; J. M. Kimble
World soils represent the largest terrestrial pool of organic carbon (C), about 1550 Pg compared with about 700 Pg in the\\u000a atmosphere and 600 Pg in land biota. Agricultural activities (e.g., deforestation, burning, plowing, intensive grazing) contribute\\u000a considerably to the atmospheric pool. Expansion of agriculture may have contributed substantially to the atmospheric carbon\\u000a pool. However, the exact magnitude of carbon
Carbon Dioxide Production at Home
NSDL National Science Digital Library
In this problem set, learners will consider the "Carbon Footprint" of a family of four in a given context, as well as the US and global averages, and compare that with their own to answer a series of questions. They will use an online Carbon Footprint calculator to determine their own per-capita carbon production. Answer key is provided. This problem is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.
Activated carbon from municipal waste
S Nagano; H Tamon; T Adzumi; K Nakagawa; T Suzuki
A refuse derived fuel (RDF) was carbonized by partial combustion at 623 K and the carbonized RDF (cRDF) was steam-activated at 1123 K. The cRDF was also treated by 3.3 or 5.2 N nitric acid at a boiling temperature for 3 h prior to the steam-activation. Porous properties of the activated carbons prepared were determined by the nitrogen adsorption method.
Carbon Nanostructures: Synthesis and Characterisations
NASA Astrophysics Data System (ADS)
Bououdina, M.
Chemical vapor deposition technique has been used to produce a variety of carbon nanostructures. Type of catalyst (Fe, Ni) and its size, temperature, gas ratio C2/H4) and time affect the type of carbon produced as well as its length and diameter. Post-treatments (oxidation, reduction) have been carried out in order to remove the amorphous-capped carbon formed at the edges of tubes and fibers.
NSDL National Science Digital Library
This activity has students explore the carbon cycle and learn to identify carbon sources, sinks, and release agents. They will come to understand that carbon is critical to the biosphere and must continue cycling to support life on earth. The instructor guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.
46 CFR 151.50-40 - Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether.
Code of Federal Regulations, 2013 CFR
...2013-10-01 false Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether. 151.50-40 Section...Requirements ¦ 151.50-40 Additional requirements for carbon disulfide (carbon bisulfide) and ethyl...
46 CFR 151.50-40 - Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether.
Code of Federal Regulations, 2014 CFR
...2014-10-01 false Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether. 151.50-40 Section...Requirements ¦ 151.50-40 Additional requirements for carbon disulfide (carbon bisulfide) and ethyl...
Stahl, David B. (Los Alamos, NM); Paisley, Dennis L. (Santa Fe, NM)
A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.
Exploring Marine Carbon Isotope Excursions
NSDL National Science Digital Library
David Jones, Geology Department, Amherst College Topic: stable isotopes, geochemistry, oceanography, carbon cycle Course type: Upper level undergraduate course Description The exercise is designed to introduce ...
Carbon Management Plan 1. Executive summary 5
Haase, Markus
Carbon Management Plan June 2011 #12;2 #12;3 CONTENTS 1. Executive summary 5 2. Introduction 15 3. Background and context 16 4. Carbon management strategy 18 5. Carbon emissions baseline and projections 22 6. Past actions and achievements 30 7. Carbon Management Plan implementation 33 8. Carbon Management Plan
Friction stir welding of carbon steels
Hidetoshi Fujii; Ling Cui; Nobuhiro Tsuji; Masakatsu Maeda; Kazuhiro Nakata; Kiyoshi Nogi
In order to determine the effect of the carbon content and the transformation on the mechanical properties and microstructures of the FSW carbon steel joints, three types of carbon steels with different carbon contents (IF steel, S12C, S35C) were friction stir welded under various welding conditions. Compared with IF steel, the microstructures and mechanical properties of the carbon steel joints
Understanding and managing the global carbon cycle
John Grace
Summary 1 Biological carbon sinks develop in mature ecosystems that have high carbon storage when these systems are stimulated to increase productivity, so that carbon gains by photosynthesis run ahead of carbon losses by heterotrophic respiration, and the stocks of carbon therefore increase. This stimulation may occur through elevated CO 2 con- centration, nitrogen deposition or by changes in climate.
The Carbon Cycle: How It Works
NSDL National Science Digital Library
Beverly L. Meier
In this game, learners walk through an imaginary Carbon Cycle and explore the ways in which carbon is stored in reservoirs and the processes that transport the carbon atom from one location to another. This resource includes background information about carbon, the carbon cycle, and climate change.
Klaas Jan Kramer; Greg Homan; Rich Brown; Ernst Worrell; Eric Masanet
The term ?household carbon footprint? refers to the total annual carbon emissions associated with household consumption of energy, goods, and services. In this project, Lawrence Berkeley National Laboratory developed a carbon footprint modeling framework that characterizes the key underlying technologies and processes that contribute to household carbon footprints in California and the United States. The approach breaks down the carbon
Multifunctional Catalysts for Singlewall Carbon Nanotube
Guo, Ting
137 7 Multifunctional Catalysts for Singlewall Carbon Nanotube Synthesis T. Guo* 7.1. INTRODUCTION Single-wall carbon nanotubes (SWNTs) are usually produced with the help of metal catalysts that first break down various carbon species such as graphite, carbon clusters, amorphous carbon, or hydrocarbons
The Global Carbon Cycle Radiative forcing
Follows, Mick
elemental ratio of plankton C:N:P = 106:16:1 Carbon typically plentiful Availability of light or otherThe Global Carbon Cycle Radiative forcing Global carbon reservoirs Glacial-interglacial cycles Anthropogenic CO2 Ocean-atmosphere partitioning Ocean carbon cycle Carbon distribution in the ocean
Carbon Diffusion Across Dissimilar Steel Welds
Race, Julia Margaret
interface to the carbide on the low carbon activity side VI v J.l J.lo J.la(J J.l(Ja fB fĘI fa f(J f) w Carbon concentration in solution on the high carbon activity side of the interface High carbon activity side of the interface Low carbon activity side...
Donado, R.A.; Hrdina, K.E.; Remick, R.J.
A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process is described for production of the lithium ferrite containing anode by slipcasting.
NASA Technical Reports Server (NTRS)
Collier, R. S.; Sparks, L. L.; Strobridge, T. R.
The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.
Carbon-Nanotube Optoelectronics
Phaedon Avouris; Marcus Freitag; Vasili Perebeinos
\\u000a Semiconducting single-walled carbon nanotubes are direct-gap materials that\\u000a provide ideal systems for the study of photophysics in one-dimension. While\\u000a their excited states involve strongly bound 1D excitons, their single atomic\\u000a layer structure makes their optical properties especially sensitive to their\\u000a environment and external fields, thus allowing for their controlled modification. In\\u000a this chapter we review the properties of the excited
NASA Astrophysics Data System (ADS)
Le Quķrķ, C.; Moriarty, R.; Andrew, R. M.; Peters, G. P.; Ciais, P.; Friedlingstein, P.; Jones, S. D.; Sitch, S.; Tans, P.; Arneth, A.; Boden, T. A.; Bopp, L.; Bozec, Y.; Canadell, J. G.; Chini, L. P.; Chevallier, F.; Cosca, C. E.; Harris, I.; Hoppema, M.; Houghton, R. A.; House, J. I.; Jain, A. K.; Johannessen, T.; Kato, E.; Keeling, R. F.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landa, C. S.; Landsch³tzer, P.; Lenton, A.; Lima, I. D.; Marland, G.; Mathis, J. T.; Metzl, N.; Nojiri, Y.; Olsen, A.; Ono, T.; Peng, S.; Peters, W.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; R÷denbeck, C.; Saito, S.; Salisbury, J. E.; Schuster, U.; Schwinger, J.; Sķfķrian, R.; Segschneider, J.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Werf, G. R.; Viovy, N.; Wang, Y.-P.; Wanninkhof, R.; Wiltshire, A.; Zeng, N.
Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2, and land-cover-change (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ▒1?, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2004-2013), EFF was 8.9 ▒ 0.4 GtC yr-1, ELUC 0.9 ▒ 0.5 GtC yr-1, GATM 4.3 ▒ 0.1 GtC yr-1, SOCEAN 2.6 ▒ 0.5 GtC yr-1, and SLAND 2.9 ▒ 0.8 GtC yr-1. For year 2013 alone, EFF grew to 9.9 ▒ 0.5 GtC yr-1, 2.3% above 2012, continuing the growth trend in these emissions, ELUC was 0.9 ▒ 0.5 GtC yr-1, GATM was 5.4 ▒ 0.2 GtC yr-1, SOCEAN was 2.9 ▒ 0.5 GtC yr-1, and SLAND was 2.5 ▒ 0.9 GtC yr-1. GATM was high in 2013, reflecting a steady increase in EFF and smaller and opposite changes between SOCEAN and SLAND compared to the past decade (2004-2013). The global atmospheric CO2 concentration reached 395.31 ▒ 0.10 ppm averaged over 2013. We estimate that EFF will increase by 2.5% (1.3-3.5%) to 10.1 ▒ 0.6 GtC in 2014 (37.0 ▒ 2.2 GtCO2 yr-1), 65% above emissions in 1990, based on projections of world gross domestic product and recent changes in the carbon intensity of the global economy. From this projection of EFF and assumed constant ELUC for 2014, cumulative emissions of CO2 will reach about 545 ▒ 55 GtC (2000 ▒ 200 GtCO2) for 1870-2014, about 75% from EFF and 25% from ELUC. This paper documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this living data set (Le Quķrķ et al., 2013, 2014). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2014).
Donado, Rafael A. (Chicago, IL); Hrdina, Kenneth E. (Glenview, IL); Remick, Robert J. (Bolingbrook, IL)
A molten alkali metal carbonates fuel cell porous anode of lithium ferrite and a metal or metal alloy of nickel, cobalt, nickel/iron, cobalt/iron, nickel/iron/aluminum, cobalt/iron/aluminum and mixtures thereof wherein the total iron content including ferrite and iron of the composite is about 25 to about 80 percent, based upon the total anode, provided aluminum when present is less than about 5 weight percent of the anode. A process for production of the lithium ferrite containing anode by slipcasting.
Carbon dioxide in the Paleozoic atmosphere: Evidence from carbon-isotope composition of pedogenic carbonate
Mora, C.I.; Driese, S.G.; Seager, P.G. (Univ. of Tennessee, Knoxville (United States))
Stable carbon-isotope compositions of pedogenic carbonate occurring in three clay-rich vertic paleosols within Paleozoic red-bed successions in central Pennsylvania provide a record of past pedogenic environments and can be used to estimate CO{sub 2} pressure (P{sub CO{sub 2}}) of the Paleozoic atmosphere. The {delta}{sup 13}C values of carbonate nodules from paleosols in the deltaic lower Bloomsburg Formation (Upper Silurian) reflect the contribution of carbon from marine groundwater or fossils, coupled with low biological activity. The {delta}{sup 13}C values of carbonate rhizocretions from stratigraphically high paleosols in the Bloomsburg Formation, and in the alluvial Catskill (Upper Devonian) and Mauch Chunk (Upper Mississippian) Formations, suggest an extensive C{sub 3} flora and significant contribution of atmospheric CO{sub 2}. Paleozoic atmospheric CO{sub 2} levels inferred from {delta}{sup 13}C of pedogenic carbonate are significantly higher than present levels.
Carbon banks: an efficient means to exchange sequestered carbon.
Esuola, Adeyemi G; Weersink, Alfons
Carbon sequestration is one of the options that can be used to reduce atmospheric carbon, but its use in an offset market is complicated by the temporary nature of sequestered carbon and the risks associated with carbon release and price. In this paper a carbon bank is proposed to handle these problems. The bank is both an aggregator and a risk bearer. Sink generators deposit their credits with the bank and are paid for maintaining their "savings" with the bank. The carbon bank is also the source where large-scale emitters can come and buy either a temporary or permanent credit and pay the bank in return for the credit and services provided. The advantages of the bank over alternative institutional designs include lower transaction costs, flexible carbon credits and price, and lower risk to risk-averse parties. The carbon bank could be an effective means to deal with many of the unresolved issues within the forthcoming Canadian offset system. PMID:16825473
Performance of granular activated carbon for total organic carbon removal
Paul V. Roberts; R. Scott Summers
The results of papers presented at the second of two conferences concerning the state of the art of the application of oxidation and adsorption techniques (including granular activated carbon) in the treatment of drinking water were analyzed for their application to GAC use in the United States. Total organic carbon was used as the parameter for measuring the removal of
Radiogenic Carbon Isotopes in Authigenic Carbonate from Lake Neusiedl, Austria
NASA Astrophysics Data System (ADS)
Neuhuber, Stephanie; Steier, Peter; Gier, Susanne; Draganits, Erich; Kogelbauer, Ilse
Formation of authigenic carbonate in Lake Neusiedl, Austia, has been reported since the 1960ies. The reaction pathways resulting in carbonate precipitation (protodolomite and high magnesium calcite) have yet to be identified. Lake Neusiedl is a shallow lake without significant sediment accumulation but constant reworking of sediment due to its shallow depth (1.8m) and influence by wind. The sediments are water-saturated silts and clays that overly Neogene sediments. The age of Lake Neusiedl is unknown due to its low sedimentation rate and constant remixing of sediment. Dating of authigenic minerals is an alternative method to determine the minimum age of water present - even episodically - at the location. We characterize the sediments mineralogy in different size fractions by X-Ray Diffractometry (XRD), Simultaneous Themo Analysis (STA) and Fourier Transform Infra Red Spectroscopy, stable carbon and oxygen isotopes as well as radiogenic carbon. To describe the authigenic carbonates and find the fractions with highest authigenic carbonate minerals we investigate the size fractions <4 Ąm, <3 Ąm, <2 Ąm, <1 Ąm, 0.5 Ąm and <0.2 Ąm. The "coarser" fractions (4 Ąm to 2 Ąm) contain detrital minerals such as chlorite, muscovite, quartz, feldspar, stoichiometric calcite and stoichiometric dolomite as well as authigenic high Mg calcite. Radiogenic carbon ages increase with increasing grain size from 850 years before present to 2300 years before present and indicate a very slow growth rate or episodic growth of authigenic carbonate phases.
The Effects of Grazing Management on Soil Carbon (Carbon Sequestration)
Richard T. Conant; Keith Paustian
This component of the VA RLEP consists of a field based sampling and research effort to document the efficacy of Management intensive Grazing (MiG) techniques to enhance the soil's inherent capacity to serve as a sink for carbon (four data collection sites were developed in VA). To the extent that MiG and associated conservation practices increase the storage of carbon
program Ł All documents and procedures generated to yield fully integrated quality system Ę SOP's, FMEA's, process control plan, etc. Ł System of continuous improvement installed Ę Examines process metrics Scale-up of Carbon/Carbon Bipolar Plates Ę Project Objectives Ł Build and demonstrate a pilot facility
Assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC)
Isabel C Escobar; Andrew A Randall
The objective of this study was to evaluate the necessity of measuring both assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC) as indicators of bacterial regrowth potential. AOC and BDOC have often been measured separately as indicators of bacterial regrowth, or together as indicators of bacterial regrowth and disinfection by-product formation potential, respectively. However, this study proposes that
Helicity of Carbon Nanotubes and Helix-shaped Carbon Nanotubes
Ji-Peng Cheng; Xiao-Bin Zhang
Determination of the helicity of carbon nanotubes (CNTs) is useful for CNTs in nanoelectronic device applications. Using electron diffraction to measure chiral angle with a high precision is reviewed, and helix-shaped carbon nanostructures are introduced and characterized by transmission electron microscopy. The possible formation mechanism of helix-shaped CNTs is also referred in the paper
Carbon Dioxide Carbonates in the Earth;s Mantle: Implications to the Deep Carbon Cycle
Yoo, Choong-Shik; Sengupta, Amartya; Kim, Minseob (Princeton); (WSU)
An increase in the ionic character in C-O bonds at high pressures and temperatures is shown by the chemical/phase transformation diagram of CO{sub 2}. The presence of carbonate carbon dioxide (i-CO{sub 2}) near the Earth's core-mantle boundary condition provides insights into both the deep carbon cycle and the transport of atmospheric CO{sub 2} to anhydrous silicates in the mantle and iron core.
Carbon Dioxide Sequestration in Concrete Using Vacuum-Carbonation Alain Azar, Prof. Yixin Shao
Barthelat, Francois
Carbon Dioxide Sequestration in Concrete Using Vacuum-Carbonation Alain Azar, Prof. Yixin Shao promising carbon uptake results and is a viable option for carbonation curing. Carbon sequestration increase in Carbon dioxide (CO2) emissions over the past five decades, specific ways to reduce
Australian climate-carbon cycle feedback reduced by soil black carbon
Johannes Lehmann; Jan Skjemstad; Saran Sohi; John Carter; Michele Barson; Pete Falloon; Kevin Coleman; Peter Woodbury; Evelyn Krull
Annual emissions of carbon dioxide from soil organic carbon are an order of magnitude greater than all anthropogenic carbon dioxide emissions taken together. Global warming is likely to increase the decomposition of soil organic carbon, and thus the release of carbon dioxide from soils, creating a positive feedback. Current models of global climate change that recognize this soil carbon feedback
Tuning Organic Carbon Dioxide Absorbents for Carbonation and Decarbonation
Rajamanickam, Ramachandran; Kim, Hyungsoo; Park, Ji-Woong
The reaction of carbon dioxide with a mixture of a superbase and alcohol affords a superbase alkylcarbonate salt via a process that can be reversed at elevated temperatures. To utilize the unique chemistry of superbases for carbon capture technology, it is essential to facilitate carbonation and decarbonation at desired temperatures in an easily controllable manner. Here, we demonstrate that the thermal stabilities of the alkylcarbonate salts of superbases in organic solutions can be tuned by adjusting the compositions of hydroxylic solvent and polar aprotic solvent mixtures, thereby enabling the best possible performances to be obtained from the various carbon dioxide capture agents based on these materials. The findings provides valuable insights into the design and optimization of organic carbon dioxide absorbents. PMID:26033537
Prospects for using carbon-carbon composites for EMI shielding
NASA Technical Reports Server (NTRS)
Gaier, James R.
Since pyrolyzed carbon has a higher electrical conductivity than most polymers, carbon-carbon composites would be expected to have higher electromagnetic interference (EMI) shielding ability than polymeric resin composites. A rule of mixtures model of composite conductivity was used to calculate the effect on EMI shielding of substituting a pyrolyzed carbon matrix for a polymeric matrix. It was found that the improvements were small, no more than about 2 percent for the lowest conductivity fibers (ex-rayon) and less than 0.2 percent for the highest conductivity fibers (vapor grown carbon fibers). The structure of the rule of mixtures is such that the matrix conductivity would only be important in those cases where it is much higher than the fiber conductivity, as in metal matrix composites.
Intermediate Temperature Carbon - Carbon Composite Structures. CRADA Final Report
Lara-Curzio, Edgar [ORNL
The objective of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC (the "Contractor") and Synterials, Inc. (the "Participant") was to demonstrate promising processing methods, which can lead to producing Carbon-Carbon Composites (CCC), with tensile and interlaminar properties comparable to those of organic matrix composites and environmental stability at 1200 F for long periods of time. The participant synthesized carbon-carbon composites with two different fiber coatings and three different matrices. Both parties evaluated the tensile and interlaminar properties of these materials and characterized the microstructure of the matrices and interfaces. It was found that fiber coatings of carbon and boron carbide provided the best environmental protection and resulted in composites with high tensile strength.
Tuning organic carbon dioxide absorbents for carbonation and decarbonation.
Rajamanickam, Ramachandran; Kim, Hyungsoo; Park, Ji-Woong
The reaction of carbon dioxide with a mixture of a superbase and alcohol affords a superbase alkylcarbonate salt via a process that can be reversed at elevated temperatures. To utilize the unique chemistry of superbases for carbon capture technology, it is essential to facilitate carbonation and decarbonation at desired temperatures in an easily controllable manner. Here, we demonstrate that the thermal stabilities of the alkylcarbonate salts of superbases in organic solutions can be tuned by adjusting the compositions of hydroxylic solvent and polar aprotic solvent mixtures, thereby enabling the best possible performances to be obtained from the various carbon dioxide capture agents based on these materials. The findings provides valuable insights into the design and optimization of organic carbon dioxide absorbents. PMID:26033537
Comparison of carbon onions and carbon blacks as conductive additives for carbon supercapacitors in organic electrolytes
NASA Astrophysics Data System (ADS)
Jõckel, N.; Weingarth, D.; Zeiger, M.; Aslan, M.; Grobelsek, I.; Presser, V.
This study investigates carbon onions (?400Ām2Āg-1) as a conductive additive for supercapacitor electrodes of activated carbon and compares their performance with carbon black with high or low internal surface area. We provide a study of the electrical conductivity and electrochemical behavior between 2.5 and 20Āmass% addition of each of these three additives to activated carbon. Structural characterization shows that the density of the resulting film electrodes depends on the degree of agglomeration and the amount of additive. Addition of low surface area carbon black (?80Ām2Āg-1) enhances the power handling of carbon electrodes but significantly lowers the specific capacitance even when adding small amounts of carbon black. A much lower decrease in specific capacitance is observed for carbon onions and the best values are seen for carbon black with a high surface area (?1390Ām2Āg-1). The overall performance benefits from the addition of any of the studied additives only at either high scan rates and/or electrolytes with high ion mobility. Normalization to the volume shows a severe decrease in volumetric capacitance and only at high current densities nearing 10ĀAĀg-1 we can see an improvement of the electrode capacitance.
Electron Beam Exposure of Thermal Control Paints on Carbon-Carbon and Carbon-Polyimide Composites
NASA Technical Reports Server (NTRS)
Jaworske, Donald A.
Carbon-carbon and carbon-polyimide composites are being considered for use as radiator face sheets or fins for space radiator applications. Several traditional white thermal control paints are being considered for the surface of the composite face sheets or fins. One threat to radiator performance is high energy electrons. The durability of the thermal control paints applied to the carbon-carbon and carbon-polyimide composites was evaluated after extended exposure to 4.5 MeV electrons. Electron exposure was conducted under argon utilizing a Mylar(TradeMark) bag enclosure. Solar absorptance and infrared emittance was evaluated before and after exposure to identify optical properties degradation. Adhesion of the paints to the carbon-carbon and carbon-polyimide composite substrates was also of interest. Adhesion was evaluated on pristine and electron beam exposed coupons using a variation of the ASTM D-3359 tape test. Results of the optical properties evaluation and the adhesion tape tests are summarized.
Mallick, Kaushik; Strydom, Andrķ M
Carbon nanotubes (CNTs) have been proposed and are actively being explored as innovative multipurpose carriers for biomolecules and diagnostic applications. Their versatile physico-chemical features enable them as a carrier of several pharmaceutically relevant entities and allow them for rational design of novel nanoscale candidates for drug development. Functionalized carbon nanotubes (f-CNT) are emerging as a new family of nanovectors for the delivery of different types of therapeutic molecules. The application of CNTs in the field of carrier-mediated delivery has become possible after the recent discovery of their capacity to penetrate into the cells. CNT can be loaded with active molecules by forming stable covalent bonds or supramolecular assemblies based on noncovalent interactions. Once the cargos are carried into various cells, tissues and organs they are able to express their biological function. In this review, we will describe the potential of f-CNT as a vehicle to deliver different types of therapeutic agents into the biological species. PMID:23384693
NASA Technical Reports Server (NTRS)
Thompson, T. E.
The effect of several chemical treatments on the electrical and mechanical properties of carbon fibers was investigated with an optimum goal of increasing the electrical resistivity by a factor of 1000 without appreciably changing the mechanical properties. It was possible to effect resistivity increases from 10 to 50 percent without adversely affecting the tensile strength or Young's modulus for T-300 and C-6000 PAN fibers by treatments with either AlCl3 or nitric acid mixtures. Larger increases in the resistivity were produced with pitch fibers treated with nitric acid mixtures. This treatment also produced a partial decomposition of the pitch fiber and deterioration of the mechanical properties. The rationale behind the approch was to immobilize the conductivity producing pi electrons in the microscopic aromatic structure of the carbon fibers without destroying the strength producing sigma bonds. The investigations indicate that certain chemical treatments can produce such results, but the total reduction in the electrical conductivity which was achieved was not large enough to impact on problems which might arise from the high conductivities of the fibers.
NASA Technical Reports Server (NTRS)
Delzeit, Lance D. (Inventor); Delzeit, Clement J. (Inventor)
A method for cleaning or otherwise removing amorphous carbon and other residues that arise in growth of a carbon nanotube (CNT) array. The CNT array is exposed to a plurality of hydroxyls or hydrogen, produced from a selected vapor or liquid source such as H2O or H2O2. and the hydroxyls or hydrogen (neutral or electrically charged) react with the residues to produce partly or fully dissolved or hydrogenated or hydroxylizated products that can be removed or separated from the CNT array. The hydroxyls or hydrogen can be produced by heating the CNT array, residue and selected vapor or liquid source or by application of an electromagnetic excitation signal with a selected frequency or range of frequencies to dissociate the selected vapor or liquid. The excitation frequency can be chirped to cover a selected range of frequencies corresponding to dissociation of the selected vapor or liquid. Sonication may be uscd to supplement dissociation of the H2O and/or H2O2.
Not Available
Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.
Introduction to Carbonate Equilibrium
NSDL National Science Digital Library
michael stapleton
The activity asks students to make observations about what occurs when two effervescent antacid tablets are placed into a beaker of water. The Students work together in groups. There are three parts to the activity. In the first part, the tablets are dropped into tap water and student groups (2-4 students) must complete a series of question sheets (one per group) that guide them through thinking about the event. In the second part, a presentation on chemical equilibrium for the carbonate system is given. The starting point is the answers received in the first part. Basic chemical reactions for the carbonate system are presented including equilibrium expressions for each reaction and discussion about open and closed systems. At the end of class, a handout is given to the students. In the third part, three beakers (acidic, neutral and basic solutions, but not indicated) are placed together and two tablets are placed into each beaker. Students are split into two groups (8-12 students) and are asked to describe why the reactions are different. Discussion follows collection of student responses in each part. Once the chemical reactions and equilibrium expressions are presented, they are involved and referenced in all discussions.
Moving Carbon, Changing Earth: Bringing the Carbon Cycle to Life
NASA Astrophysics Data System (ADS)
Zabel, I.; Duggan-Haas, D.; Ross, R. M.; Stricker, B.; Mahowald, N. M.
The carbon cycle presents challenges to researchers - in how to understand the complex interactions of fluxes, reservoirs, and systems - and to outreach professionals - in how to get across the complexity of the carbon cycle and still make it accessible to the public. At Cornell University and the Museum of the Earth in Ithaca, NY, researchers and outreach staff tackled these challenges together through a 2013 temporary museum exhibition: Moving Carbon, Changing Earth. Moving Carbon, Changing Earth introduced visitors to the world of carbon and its effect on every part of our lives. The exhibit was the result of the broader impacts portion of an NSF grant awarded to Natalie Mahowald, Professor in the Department of Earth and Atmospheric Sciences at Cornell University, who has been working with a team to improve simulations of regional and decadal variability in the carbon cycle. Within the exhibition, visitors used systems thinking to understand the distribution of carbon in and among Earth's systems, learning how (and how quickly or slowly) carbon moves between and within these systems, the relative scale of different reservoirs, and how carbon's movement changes climate and other environmental dynamics. Five interactive stations represented the oceans, lithosphere, atmosphere, biosphere, and a mystery reservoir. Puzzles, videos, real specimens, and an interview with Mahowald clarified and communicated the complexities of the carbon cycle. In this talk we'll present background information on Mahowald's research as well as photos of the exhibition and discussion of the components and motivations behind them, showing examples of innovative ways to bring a complex topic to life for museum visitors.
46 CFR 153.1040 - Carbon disulfide.
Code of Federal Regulations, 2013 CFR
...2013-10-01 2013-10-01 false Carbon disulfide. 153.1040 Section 153...Special Cargo Procedures ¦ 153.1040 Carbon disulfide. (a) No person may load, carry, or discharge carbon disulfide unless the cargo tank...
46 CFR 153.1040 - Carbon disulfide.
Code of Federal Regulations, 2014 CFR
...2014-10-01 2014-10-01 false Carbon disulfide. 153.1040 Section 153...Special Cargo Procedures ¦ 153.1040 Carbon disulfide. (a) No person may load, carry, or discharge carbon disulfide unless the cargo tank...
On carbon footprints and growing energy use
Oldenburg, C.M.
supply comes from carbon-rich fossil fuel sources 1 whosespecial low-carbon mix of which 60% is from non-fossil- fuelfossil fuels as they are used today makes energy consumption a useful proxy for carbon
21 CFR 582.1425 - Magnesium carbonate.
Code of Federal Regulations, 2010 CFR
... 2010-04-01 2010-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives ¦ 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....
An Evolutionary Approach to Activated Carbon Treatment
Pierre Schulhof
Activated carbon has been successfully used in France to remove organics and limit the use of chlorine through two processesŚ simple filtration on activated carbon beds and double filtration on sand and carbon combined with ozonation.
21 CFR 582.1742 - Sodium carbonate.
Code of Federal Regulations, 2013 CFR
...2013-04-01 2013-04-01 false Sodium carbonate. 582.1742 Section 582...Purpose Food Additives ¦ 582.1742 Sodium carbonate. (a) Product. Sodium carbonate. (b) Conditions of use. This substance is generally...
21 CFR 582.1742 - Sodium carbonate.
Code of Federal Regulations, 2014 CFR
...2014-04-01 2014-04-01 false Sodium carbonate. 582.1742 Section 582...Purpose Food Additives ¦ 582.1742 Sodium carbonate. (a) Product. Sodium carbonate. (b) Conditions of use. This substance is generally...
21 CFR 582.1742 - Sodium carbonate.
Code of Federal Regulations, 2011 CFR
...2011-04-01 2011-04-01 false Sodium carbonate. 582.1742 Section 582...Purpose Food Additives ¦ 582.1742 Sodium carbonate. (a) Product. Sodium carbonate. (b) Conditions of use. This substance is generally...
21 CFR 582.1742 - Sodium carbonate.
Code of Federal Regulations, 2010 CFR
...2010-04-01 2010-04-01 false Sodium carbonate. 582.1742 Section 582...Purpose Food Additives ¦ 582.1742 Sodium carbonate. (a) Product. Sodium carbonate. (b) Conditions of use. This substance is generally...
21 CFR 582.1425 - Magnesium carbonate.
Code of Federal Regulations, 2011 CFR
... 2011-04-01 2011-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives ¦ 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....
21 CFR 582.1425 - Magnesium carbonate.
Code of Federal Regulations, 2012 CFR
... 2012-04-01 2012-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives ¦ 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....
21 CFR 582.1425 - Magnesium carbonate.
Code of Federal Regulations, 2014 CFR
... 2014-04-01 2014-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives ¦ 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....
21 CFR 582.1425 - Magnesium carbonate.
Code of Federal Regulations, 2013 CFR
... 2013-04-01 2013-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives ¦ 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....
Carbon Dioxide Reduction Through Urban Forestry
Standiford, Richard B.
Carbon Dioxide Reduction Through Urban Forestry: Guidelines for Professional and Volunteer Tree; Simpson, James R. 1999. Carbon dioxide reduction through urban forestry of Agriculture; 237 p. Carbon dioxide reduction through urban forestry--Guidelines for professional and volunteer
Big Sky Carbon Sequestration Partnership
Susan M. Capalbo
The Big Sky Carbon Sequestration Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts under this Partnership in Phase I fall into four areas: evaluation of sources and carbon sequestration sinks that will be used to determine the location
Transport Through Carbon Nanotube Wires
NASA Technical Reports Server (NTRS)
Anantram, M. P.; Kwak, Dochan (Technical Monitor)
This viewgraph presentation deals with the use of carbon nanotubes as a transport system. Contact, defects, tubular bend, phonons, and mechanical deformations all contribute to reflection within the nanotube wire. Bragg reflection, however, is native to an ideal energy transport system. Transmission resistance depends primarily on the level of energy present. Finally, the details regarding coupling between carbon nanotubes and simple metals are presented.
The report summarizes the assessment of air emissions from the manufacture of carbon black, currently manufactured in the U.S. by two major processes: thermal and oil furnace. Sources of atmospheric emissions within oil furnace plants (about 90% of the 30 U.S. carbon black plants...
Technology Transfer Automated Retrieval System (TEKTRAN)
It has been previously reported that dialkyl carbonates represent attractive lubricants, in part, to their ampiphilic nature and their decomposition to non-corrosive simple alcohols and carbon dioxide. Members of our labs previously examined such materials as additives for biodiesel applications an...
Forest soils and carbon sequestration
R. Lal
Soils in equilibrium with a natural forest ecosystem have high carbon (C) density. The ratio of soil:vegetation C density increases with latitude. Land use change, particularly conversion to agricultural ecosystems, depletes the soil C stock. Thus, degraded agricultural soils have lower soil organic carbon (SOC) stock than their potential capacity. Consequently, afforestation of agricultural soils and management of forest plantations
Carbon Sequestration in Campus Trees
NSDL National Science Digital Library
Robert S. Cole
In this activity, students use a spreadsheet to calculate the net carbon sequestration in a set of trees; they will utilize an allometric approach based upon parameters measured on the individual trees. They determine the species of trees in the set, measure trunk diameter at a particular height, and use the spreadsheet to calculate carbon content of the tree using forestry research data.
Torsional Electromechanics of Carbon Nanotubes
Ernesto Joselevich; Tzahi Cohen-Karni; Lior Segev; Onit Srur-Lavi; Sidney R. Cohen
Carbon nanotubes are known to be distinctly metallic or semiconducting depending on their diameter and chirality. Here we show that continuously varying the chirality by mechanical torsion can induce conductance oscillations, which can be attributed to metal-semiconductor periodic transitions. The phenomenon is observed in multi-walled carbon nanotubes, where both the torque and the current are shown to be carried predominantly
J. Robertson
Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications
Technology Transfer Automated Retrieval System (TEKTRAN)
Carbon sequestration potential for irrigated grazing lands is significant. We measured organic and inorganic carbon stored in southern Idaho soils having long-term land use histories that supported native sagebrush vegetation (NSB), irrigated pasture systems (IP), irrigated conservation tillage sit...
Viewpoint Carbon-negative biofuels
John A. Mathews
Current Kyoto-based approaches to reducing the earth's greenhouse gas problem involve looking for ways to reduce emissions. But these are palliative at best, and at worst will allow the problem to get out of hand. It is only through sequestration of atmospheric carbon that the problem can be solved. Carbon-negative biofuels represent the first potentially huge assault on the problem,
Carbon dioxide and terrestrial ecosystems
G. W. Koch; H. A. Mooney
This book is a summary of the current research which addresses the effects of elevated carbon dioxide on terrestrial ecosystems and an identification of significant unresolved issues. Chapters address the carbon dioxide effects on trees and forests, unmanaged herbaceous ecosystems, and crops. Included are experimental studies, conceptual models, general mathematical models, dynamic simulation models.
Powicki, C.R.
The global carbon cycle involves constant exchange of carbon atoms between the atmosphere, land, and ocean through biological, chemical and geological processes. This natural cycle of uptake and release of carbon is roughly in balance. However, the global industrialization of the past two centuries has released carbon to the atmosphere, mostly in the form of CO{sub 2} that had been locked up in underground coal, oil, and natural gas deposits for millions of years. It is primarily combustion of these long-stored fossil fuels that threatens to tip the balance of the carbon cycle, leading to a substantial buildup of CO{sub 2} in the upper atmosphere. Scientists believe that one key to stabilizing future atmospheric CO{sub 2} concentrations will be essentially to close the fuel carbon cycle, to capture the carbon from fossil fuels before it is released to the atmosphere and return it to permanent reservoirs in the earth or oceans. The article summarises the various options for carbon capture and storage (CCS) and looks at the state of development of technologies. It also addresses regulatory uncertainties, legal issues risks and perceptions of CCS. 3 figs., 1 tab.
Permafrost soils and carbon cycling
NASA Astrophysics Data System (ADS)
Ping, C. L.; Jastrow, J. D.; Jorgenson, M. T.; Michaelson, G. J.; Shur, Y. L.
Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global carbon cycle and the potential vulnerability of the region's soil organic carbon (SOC) stocks to changing climatic conditions. In this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils, and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of organic carbon stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this organic carbon to permafrost thaw under a warming climate. Overall, frozen conditions and cryopedogenic processes, such as cryoturbation, have slowed decomposition and enhanced the sequestration of organic carbon in permafrost-affected soils over millennial timescales. Due to the low temperatures, the organic matter in permafrost soils is often less humified than in more temperate soils, making some portion of this stored organic carbon relatively vulnerable to mineralization upon thawing of permafrost.
Carbon Dioxide: Friend or Foe?
C. Muller
Carbon Dioxide: Friend or Foe is a short rnonograph on the so-called carbon dioxide greenhouse effect. The author challenges the established view that the present CO2 increase would, in the long term, lead to a global ground temperature increase. S. B. Idso, from four sets of observations, has deduced that the temperature response to an increased received energy at the
Local structure of nanoporous carbons
V. Petkov; R. G. Difrancesco; S. J. L. Billinge; M. Acharya; H. C. Foley
The local atomic structure of nanoporous carbons produced by pyrolysis of poly(furfuryl alcohol) at various temperatures has been studied using neutron diffraction. Atomic pair distribution functions (PDFs) were obtained from the neutron data. Structure models have been fitted to the PDFs to understand the fine features of atomic ordering. It has been found that carbons produced at 800 and 1200
Local structure of nanoporous carbons
V. Petkov; R. G. Difrancesco; S. J. L. Billinge; M. Acharya; H. C. Foley
The local atomic structure of nanoporous carbons produced by pyrolysis of poly(furfuryl alcohol) at various temperatures has been studied using neutron diffraction. Atomic pair distribution functions (PDFs) were obtained from the neutron data. Structure models have been fitted to the PDFs to understand the fine features of atomic ordering. It has been found that carbons produced at 800 and 1200░C
Psychological effectiveness of carbon labelling
NASA Astrophysics Data System (ADS)
Beattie, Geoffrey
Despite the decision by supermarket-giant Tesco to delay its plan to add carbon-footprint information onto all of its 70,000 products, carbon labelling, if carefully designed, could yet change consumer behaviour. However, it requires a new type of thinking about consumers and much additional work.
Carbon Dioxide Capture and Disposal
K. S. Lackner
Unless carbon dioxide from fossil fuel combustion is captured and disposed of safely and permanently, the concerns over climate change will eventually lead to the demise of fossil fuels. Because of their importance in today's energy market the phasing out of fossil fuels would likely precipitate a major energy crisis. Mineral sequestration and extraction of carbon dioxide from the air
Plasmachemical Synthesis of Carbon SuboxideĀ
Geiger, Robert
A nonthermal carbon monoxide plasma is known to produce a solid deposition which is thought to be a polymer of carbon suboxide (C3O2); however there are very few investigations of this deposition in the literature. This thesis contains an analysis...
Coral reefs and carbon dioxide
Buddemeier, R.W. [Kansas Geological Survey, Lawrence, KS (United States)
This commentary argues the conclusion from a previous article, which investigates diurnal changes in carbon dioxide partial pressure and community metabolism on coral reefs, that coral `reefs might serve as a sink, not a source, for atmospheric carbon dioxide.` Commentaries from two groups are given along with the response by the original authors, Kayanne et al. 27 refs.
Activated carbon to the rescue
This article describes the response to pipeline spill of ethylene dichloride (EDC) on the property of an oil company. Activated carbon cleanup proceedure was used. During delivery, changeout, transport, storage, thermal reactivation, and return delivery to the site, the carbon never came into direct contact with operating personnel or the atmosphere. More than 10,000 tones of dredge soil and 50
Carbon Nanomaterials: The Ideal Interconnect
Carbon Nanomaterials: The Ideal Interconnect Technology for Next- Generation ICs Hong Li, Chuan Xu-generation ICs. In this research, carbon nanomaterials, with their many attractive properties, are emerging-chip interconnects. In this article, we discuss various car- bon nanomaterials, along with their prospects for next
Permafrost soils and carbon cycling
Ping, C. L.; Jastrow, J. D.; Jorgenson, M. T.; Michaelson, G. J.; Shur, Y. L.
Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This knowledge has also called attention to the importance of permafrost-affected soils to the global carbon cycle and the potential vulnerability of the region's soil organic carbon (SOC) stocks to changing climatic conditions. InmoreĀ╗this review, we briefly introduce the permafrost characteristics, ice structures, and cryopedogenic processes that shape the development of permafrost-affected soils, and discuss their effects on soil structures and on organic matter distributions within the soil profile. We then examine the quantity of organic carbon stored in permafrost-region soils, as well as the characteristics, intrinsic decomposability, and potential vulnerability of this organic carbon to permafrost thaw under a warming climate. Overall, frozen conditions and cryopedogenic processes, such as cryoturbation, have slowed decomposition and enhanced the sequestration of organic carbon in permafrost-affected soils over millennial timescales. Due to the low temperatures, the organic matter in permafrost soils is often less humified than in more temperate soils, making some portion of this stored organic carbon relatively vulnerable to mineralization upon thawing of permafrost.½Āless
Carbon nanotubes: opportunities and challenges
Hongjie Dai
Carbon nanotubes are graphene sheets rolled-up into cylinders with diameters as small as one nanometer. Extensive work carried out worldwide in recent years has revealed the intriguing electrical and mechanical properties of these novel molecular scale wires. It is now well established that carbon nanotubes are ideal model systems for studying the physics in one-dimensional solids and have significant potential
Process for making hollow carbon spheres
Luhrs, Claudia C.; Phillips, Jonathan; Richard, Monique N.; Knapp, Angela Michelle
A hollow carbon sphere having a carbon shell and an inner core is disclosed. The hollow carbon sphere has a total volume that is equal to a volume of the carbon shell plus an inner free volume within the carbon shell. The inner free volume is at least 25% of the total volume. In some instances, a nominal diameter of the hollow carbon sphere is between 10 and 180 nanometers.
Catalysis of methane decomposition over elemental carbon
N. Muradov
Catalytic decomposition of methane is an attractive method for CO\\/CO2-free production of hydrogen, particularly, for fuel cell applications. Over 30 different samples of elemental carbon, including a variety of activated carbons (ACs), carbon blacks (CBs), nanostructured carbons (including, carbon nanotubes and fullerenes C60\\/70), graphites, glassy carbon and synthetic diamond powders, were screened for the catalytic activity in methane decomposition reaction.
Method for producing carbon nanotubes
Phillips, Jonathan (Santa Fe, NM); Perry, William L. (Jemez Springs, NM); Chen, Chun-Ku (Albuquerque, NM)
Method for producing carbon nanotubes. Carbon nanotubes were prepared using a low power, atmospheric pressure, microwave-generated plasma torch system. After generating carbon monoxide microwave plasma, a flow of carbon monoxide was directed first through a bed of metal particles/glass beads and then along the outer surface of a ceramic tube located in the plasma. As a flow of argon was introduced into the plasma through the ceramic tube, ropes of entangled carbon nanotubes, attached to the surface of the tube, were produced. Of these, longer ropes formed on the surface portion of the tube located in the center of the plasma. Transmission electron micrographs of individual nanotubes revealed that many were single-walled.
Molecular Structure of Carbon Dioxide
NSDL National Science Digital Library
Carbon dioxide was first described in the 17th century by Jan Baptist van Helmont, a Belgium chemist. The chemical CO2 is released into the atmosphere when carbon-containing fossil fuels like oil, natural gas, and coal are burned in air. It is also produced by various microorganisms in fermentation and is breathed out by animals. Plants absorb carbon dioxide during photosynthesis, using both the carbon and the oxygen to construct carbohydrates. Every year the amount of CO2 in the atmosphere is increasing. CO2 build-up in the atmosphere is caused by deforestation, therefore reducing the number of trees available to absorb CO2. Excess CO2 in the environment causes Global Warming and the Greenhouse Effect. It is also toxic to humans since inhalation of large amounts of CO2 can cause suffocation. Some beverages, such as beer and sparkling wine contain carbon dioxide as a result of fermentation.
Natural materials for carbon capture.
Myshakin, Evgeniy M. (National Energy Technology Laboratory, Pittsburgh, PA); Romanov, Vyacheslav N. (National Energy Technology Laboratory, Pittsburgh, PA); Cygan, Randall Timothy
Naturally occurring clay minerals provide a distinctive material for carbon capture and carbon dioxide sequestration. Swelling clay minerals, such as the smectite variety, possess an aluminosilicate structure that is controlled by low-charge layers that readily expand to accommodate water molecules and, potentially, carbon dioxide. Recent experimental studies have demonstrated the efficacy of intercalating carbon dioxide in the interlayer of layered clays but little is known about the molecular mechanisms of the process and the extent of carbon capture as a function of clay charge and structure. A series of molecular dynamics simulations and vibrational analyses have been completed to assess the molecular interactions associated with incorporation of CO2 in the interlayer of montmorillonite clay and to help validate the models with experimental observation.
Catalytic Growth of Macroscopic Carbon Nanofibers Bodies with Activated Carbon
Abdullah, N.; Muhammad, I. S.; Hamid, S. B. Abd. [NANOCEN, Block A, Level 3, Institute of Postgraduate Studies, University of Malaya, 50603 Kuala Lumpur (Malaysia); Rinaldi, A. [NANOCEN, Block A, Level 3, Institute of Postgraduate Studies, University of Malaya, 50603 Kuala Lumpur (Malaysia); Inorganic Chemistry Department, Fritz-Haber Institute der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Su, D. S.; Schlogl, R. [Inorganic Chemistry Department, Fritz-Haber Institute der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany)
Carbon-carbon composite of activated carbon and carbon nanofibers have been synthesized by growing Carbon nanofiber (CNF) on Palm shell-based Activated carbon (AC) with Ni catalyst. The composites are in an agglomerated shape due to the entanglement of the defective CNF between the AC particles forming a macroscopic body. The macroscopic size will allow the composite to be used as a stabile catalyst support and liquid adsorbent. The preparation of CNT/AC nanocarbon was initiated by pre-treating the activated carbon with nitric acid, followed by impregnation of 1 wt% loading of nickel (II) nitrate solutions in acetone. The catalyst precursor was calcined and reduced at 300 deg. C for an hour in each step. The catalytic growth of nanocarbon in C{sub 2}H{sub 4}/H{sub 2} was carried out at temperature of 550 deg. C for 2 hrs with different rotating angle in the fluidization system. SEM and N{sub 2} isotherms show the level of agglomeration which is a function of growth density and fluidization of the system. The effect of fluidization by rotating the reactor during growth with different speed give a significant impact on the agglomeration of the final CNF/AC composite and thus the amount of CNFs produced. The macrostructure body produced in this work of CNF/AC composite will have advantages in the adsorbent and catalyst support application, due to the mechanical and chemical properties of the material.
Organic carbon in soil and the global carbon cycle
Post, W.M. III.
Soil organic matter is, simultaneously, the most inert carbon cycle component of terrestrial ecosystems, and the most dynamic component of terrestrail geologic systems placing it in a pivotal position in the biogeochemistry of carbon. The large size and potentially long residence time of the soil organic matter pool make it an important component of the global carbon cycle. Net terrestrial primary production of about 60 Pg C{center dot}yr{sup {minus}1} is, over a several-year period of time, balanced by an equivalent flux of litter production and subsequent decomposition of detritus and soil organic matter. However, the input rates and decomposition rates for different terrestrial ecosystems vary over several orders of magnitude resulting in widely different amounts and turnover rates of soil organic matter. The amounts of carbon stored in soils and the rates of exchange of soil carbon with the atmosphere depend on many factors related to the chemistry, biology, and physics of soil and soil organic matter. This report discusses work on organic carbon in soil and aspects of the carbon cycle.
Organic carbon in soil and the global carbon cycle
Post, W.M. III
Soil organic matter is, simultaneously, the most inert carbon cycle component of terrestrial ecosystems, and the most dynamic component of terrestrail geologic systems placing it in a pivotal position in the biogeochemistry of carbon. The large size and potentially long residence time of the soil organic matter pool make it an important component of the global carbon cycle. Net terrestrial primary production of about 60 Pg C{center_dot}yr{sup {minus}1} is, over a several-year period of time, balanced by an equivalent flux of litter production and subsequent decomposition of detritus and soil organic matter. However, the input rates and decomposition rates for different terrestrial ecosystems vary over several orders of magnitude resulting in widely different amounts and turnover rates of soil organic matter. The amounts of carbon stored in soils and the rates of exchange of soil carbon with the atmosphere depend on many factors related to the chemistry, biology, and physics of soil and soil organic matter. This report discusses work on organic carbon in soil and aspects of the carbon cycle.
Four advances in carbon-carbon materials technology
NASA Technical Reports Server (NTRS)
Maahs, Howard G.; Vaughn, Wallace L.; Kowbel, Witold
Carbon-carbon composites are a specialty class of materials having many unique properties making these composites attractive for a variety of demanding engineering applications. Chief among these properties are exceptional retention of mechanical properties at temperatures as high as 4000 F, excellent creep resistance, and low density (1.6 to 1.8 g/cu cm). Although carbon-carbon composites are currently in service in a variety of applications, much development work remains to be accomplished before these materials can be considered to be fully mature, realizing their full potential. Four recent technology advances holding particular promise for overcoming current barriers to the wide-spread commercialization of carbon-carbon composites are described. These advances are: markedly improved interlaminar strengths (more than doubled) of two dimensional composites achieved by whiskerization of the fabric reinforcing plies, simultaneously improved oxidation resistance and mechanical properties achieved by the incorporation of matrix-phase oxidation inhibitors based on carborane chemistry, improved oxidation resistance achieved by compositionally graded oxidation protective coatings, and markedly reduced processing times (hours as opposed to weeks or months) accomplished through a novel process of carbon infiltration and coatings deposition based on the use of liquid-phase precursor materials.
NASA Technical Reports Server (NTRS)
Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)
An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.
NASA Technical Reports Server (NTRS)
Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)
An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.
Houghton, R.A.; Woodwell, R.M. [Woods Hole Research Center, Woods Hole, MA (United States)
When the nations of the world signed and later ratified the United Nations Framework Convention on Climate Change (FCCC), they accepted the difficult challenge of stabilizing the composition of the atmosphere with respect to the greenhouse gases (GHGs). Success will require a reduction in both use of fossil fuels and rates of deforestation. Forests have a large enough influence on the atmosphere that one of the options for stabilizing the concentrations of GHGs in the atmosphere includes the use of forests as a carbon sink through reforestation of large areas. We identify in this paper the potential and the limitations of such projects. We discuss the implications of four approaches in management of forests globally: (i) continued deforestation, (ii) halting deforestation, (iii) net reforestation including agroforestry, and (iv) substituting the use of wood fuels for fossil fuels.
NASA Technical Reports Server (NTRS)
2004-01-017 July 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a mid-summer view of the south polar residual cap at full MOC resolution, 1.5 m (5 ft) per pixel. During each of the three summers since the start of the MGS mapping mission in March 1999, the scarps that form mesas and pits in the 'Swiss cheese'-like south polar terrain have retreated an average of about 3 meters (1 yard). The material is frozen carbon dioxide; another 3 meters or so of each scarp is expected to be removed during the next summer, in late 2005. This image is located near 86.0oS, 350.8oW, and covers an area about 1.5 km (0.9 mi) wide. Sunlight illuminates the scene from the top/upper left.
Helium diffusion in carbonates
NASA Astrophysics Data System (ADS)
Amidon, W. H.; Cherniak, D. J.; Watson, E. B.; Hobbs, D.
The abundance and large grain size of carbonate minerals make them a potentially attractive target for 4He thermochronology and 3He cosmogenic dating, although the diffusive properties of helium in carbonates remain poorly understood. This work characterizes helium diffusion in calcite and dolomite to better understand the crystal-chemical factors controlling He transport and retentivity. Slabs of cleaved natural calcite and dolomite, and polished sections of calcite cut parallel or normal to c, were implanted with 3He at 3 MeV with a dose of 5x1015/cm2. Implanted carbonates were heated in 1-atm furnaces, and 3He distributions following diffusion anneals were profiled with Nuclear Reaction Analysis using the reaction 3He(d,p)4He. For 3He transport normal to cleavage surfaces in calcite, we obtain the following Arrhenius relation over the temperature range 78-300░C: Dcalcite = 9.0x10-9exp(-55 ū 6 kJ mol-1/RT) m2sec-1. Diffusion in calcite exhibits marked anisotropy, with diffusion parallel to c about two orders of magnitude slower than diffusion normal to cleavage faces. He diffusivities for transport normal to the c-axis are similar in value to those normal to cleavage surfaces. Our findings are broadly consistent with helium diffusivities from step-heating measurements of calcite by Copeland et al. (2007); these bulk degassing data may reflect varying effects of diffusional anisotropy. Helium diffusion normal to cleavage surfaces in dolomite is significantly slower than diffusion in calcite, and has a much higher activation energy for diffusion. For dolomite, we obtain the following Arrhenius relation for He diffusion over the temperature range 150-400░C: Ddolomite = 9.0x10-8exp(-92 ū 9 kJ mol-1/RT) m2sec-1. The role of crystallographic structure in influencing these differences among diffusivities was evaluated using the maximum aperture approach of Cherniak and Watson (2011), in which crystallographic structures are sectioned along possible diffusion directions and the maximum interstitial apertures in each 'slice' in the structure are identified. Preliminary results show that observed differences in diffusivities are consistent with the size of the smallest maximum aperture along each diffusion direction. In calcite, the smallest maximum apertures are ~0.92 and ~0.66 angstroms for cleavage-normal and c-axis parallel directions respectively. In dolomite, the smallest maximum aperture is ~0.78 angstroms for the cleavage normal direction. Work is in progress on characterizing helium diffusion for other orientations in dolomite, and in other carbonates, including aragonite and magnesite, and in implementing these diffusion findings in the interpretation and modeling of bulk volume diffusion in heterogeneous calcite crystals common in many geologic applications. Copeland et al. (2007) GCA 71, 4488-4511 Cherniak and Watson, (2011) Chem. Geo. 288, 149-161
Carbon Nanotube based Nanotechnolgy
NASA Astrophysics Data System (ADS)
Meyyappan, M.
Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.
Carbon nanotube terahertz detector.
He, Xiaowei; Fujimura, Naoki; Lloyd, J Meagan; Erickson, Kristopher J; Talin, A Alec; Zhang, Qi; Gao, Weilu; Jiang, Qijia; Kawano, Yukio; Hauge, Robert H; Lķonard, Franńois; Kono, Junichiro
Terahertz (THz) technologies are promising for diverse areas such as medicine, bioengineering, astronomy, environmental monitoring, and communications. However, despite decades of worldwide efforts, the THz region of the electromagnetic spectrum still continues to be elusive for solid state technology. Here, we report on the development of a powerless, compact, broadband, flexible, large-area, and polarization-sensitive carbon nanotube THz detector that works at room temperature. The detector is sensitive throughout the entire range of the THz technology gap, with responsivities as high as ?2.5 V/W and polarization ratios as high as ?5:1. Complete thermoelectric and opto-thermal characterization together unambiguously reveal the photothermoelectric origin of the THz photosignal, triggered by plasmonic absorption and collective antenna effects, and suggest that judicious design of thermal management and quantum engineering of Seebeck coefficients will lead to further enhancement of device performance. PMID:24875576
Sonoluminescence of carbon nanotubes
NASA Astrophysics Data System (ADS)
Roslyak, Oleksiy; Andrei, Piryatinski
We report strong reduction in photoluminescence spectra of single wall semiconducting carbon nanotubes in presence of surface acoustical wave (SAW) in a piezoelectric substrate. In conventional Stark effect the excitonic oscillator strength is effectively transferred to the electron-hole manifold by reducing the exciton binding energy. Or formalism attributes the reduction to an effective damping of the electron velocity matrix elements at the Van Hove singularities of the SAW induced super-lattice. The effect manifests itself in absorption spectra by reducing the peaks amplitudes linearly with SAW amplitude in the GHz acoustical regime. Crossover to the Stark-like quadratic dependence on SAW amplitude occurs in low THz regime. We also report better quenching of higher order exciton absorption peaks as compared to the lowest optically active exciton.
Souliķ-Ziakovic, Corinne; Nicola , Renaud; Prevoteau, Alexandre; Leibler, Ludwik
A method is proposed to produce nanoparticles dispersible and recyclable in any class of solvents, and the concept is illustrated with the carbon nanotubes. Classically, dispersions of CNTs can be achieved through steric stabilization induced by adsorbed or grafted polymer chains. Yet, the surface modification of CNTs surfaces is irreversible, and the chemical nature of the polymer chains imposes the range of solvents in which CNTs can be dispersed. To address this limitation, supramolecular bonds can be used to attach and to detach polymer chains from the surface of CNTs. The reversibility of supramolecular bonds offers an easy way to recycle CNTs as well as the possibility to disperse the same functional CNTs in any type of solvent, by simply adapting the chemical nature of the stabilizing chains to the dispersing medium. The concept of supramolecular functionalization can be applied to other particles, for example, silica or metal oxides, as well as to dispersing in polymer melts, films or coatings. PMID:24458908
NASA Technical Reports Server (NTRS)
Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.
The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.
A 400 million year carbon isotope record of pedogenic carbonate: Implications for paleoatmospheric carbon dioxide
D. D. Ekart; T. E. Cerling; I. P. Montanez; N. J. Tabor
A 400 record of atmospheric carbon dioxide levels has been estimated by applying a COŌ paleobarometer to a database of 758 analyses of paleosol (fossil soil) carbonates. This database is a compilation of new data and previously published values from the literature. Many new analyses of Mesozoic paleosols are reported, an era poorly represented in the literature. Results indicate that
NASA Astrophysics Data System (ADS)
Ogumi, Zempachi; Wang, Hongyu
Accompanying the impressive progress of human society, energy storage technologies become evermore urgent. Among the broad categories of energy sources, batteries or cells are the devices that successfully convert chemical energy into electrical energy. Lithium-based batteries stand out in the big family of batteries mainly because of their high-energy density, which comes from the fact that lithium is the most electropositive as well as the lightest metal. However, lithium dendrite growth after repeated charge-discharge cycles easily will lead to short-circuit of the cells and an explosion hazard. Substituting lithium metal for alloys with aluminum, silicon, zinc, and so forth could solve the dendrite growth problem.1 Nevertheless, the lithium storage capacity of alloys drops down quickly after merely several charge-discharge cycles because the big volume change causes great stress in alloy crystal lattice, and thus gives rise to cracking and crumbling of the alloy particles. Alternatively, Sony Corporation succeeded in discovering the highly reversible, low-voltage anode, carbonaceous material and commercialized the C/LiCoO2 rocking chair cells in the early 1990s.2 Figure 3.1 schematically shows the charge-discharge process for reversible lithium storage in carbon. By the application of a lithiated carbon in place of a lithium metal electrode, any lithium metal plating process and the conditions for the growth of irregular dendritic lithium could be considerably eliminated, which shows promise for reducing the chances of shorting and overheating of the batteries. This kind of lithium-ion battery, which possessed a working voltage as high as 3.6 V and gravimetric energy densities between 120 and 150 Wh/kg, rapidly found applications in high-performance portable electronic devices. Thus the research on reversible lithium storage in carbonaceous materials became very popular in the battery community worldwide.
NASA Astrophysics Data System (ADS)
Finlator, Kristian; Thompson, Robert; Huang, Shuiyao; Davķ, Romeel; Zackrisson, E.; Oppenheimer, B. D.
Observations suggest that C II was more abundant than C IV in the intergalactic medium towards the end of the hydrogen reionization epoch (z ś 6). This transition provides a unique opportunity to study the enrichment history of intergalactic gas and the growth of the ionizing ultraviolet background (UVB) at early times. We study how carbon absorption evolves from z = 10 to 5 using a cosmological hydrodynamic simulation that includes a self-consistent multifrequency UVB as well as a well-constrained model for galactic outflows to disperse metals. Our predicted UVB is within ś2-4 times of that from Haardt & Madau, which is fair agreement given the uncertainties. Nonetheless, we use a calibration in post-processing to account for Lyman ? forest measurements while preserving the predicted spectral slope and inhomogeneity. The UVB fluctuates spatially in such a way that it always exceeds the volume average in regions where metals are found. This implies both that a spatially uniform UVB is a poor approximation and that metal absorption is not sensitive to the epoch when H II regions overlap globally even at column densities of 1012 cm-2. We find, consistent with observations, that the C II mass fraction drops to low redshift while C IV rises owing the combined effects of a growing UVB and continued addition of carbon in low-density regions. This is mimicked in absorption statistics, which broadly agree with observations at z = 6-3 while predicting that the absorber column density distributions rise steeply to the lowest observable columns. Our model reproduces the large observed scatter in the number of low-ionization absorbers per sightline, implying that the scatter does not indicate a partially neutral Universe at z ś 6.
Re-carbonized vitreous carbon substrates for optical applications
NASA Astrophysics Data System (ADS)
Nascimento, F.; DamiŃo, A. J.; Santos, M. V. R.; Origo, F. D.; Reis, J. F.; Trevenzolli, L.; Gaspar, A. C. M.; Baesso, J.
Imaging optical systems components for satellites must have low specific mass and high stiffness, as weight is a problem for payloads and stiffness is essential to keep the substrate front surface shape. In this work, Re-carbonized Vitreous Carbon (RVC) was tested as a substrate material. The process to obtain RVC is different from the traditional process to obtain the Monolithic Vitreous Carbon (MVC). It is essential to understand the process to evaluate the surface roughness data. This work describes the process to obtain RVC, as a candidate for optical component substrate, and the results of its surface roughness measurements.
Structural dynamics of carbon- and metal- containing carbon clusters
NASA Astrophysics Data System (ADS)
Clemmer, David E.; Jarrold, Martin F.
A summary of recent studies of the geometries and structural dynamics of pure carbon and metal containing carbon clusters is given. For pure carbon clusters the bicyclic and polycyclic rings can be converted into either monocyclic rings or fullerenes. Formation of the monocyclic rings is driven by a decrease in the strain energy, while fullerene formation is driven by formation of the stable fullerene cage. Mechanisms which explain the formation of bicyclic and polycyclic rings, as well as the conversion of these into monocyclic rings and fullerenes are discussed.
Carbon Cycling with Nuclear Power
NASA Astrophysics Data System (ADS)
Lackner, Klaus S.
Liquid hydrocarbon fuels like gasoline, diesel or jet fuel are the most efficient ways of delivering energy to the transportation sector, in particular cars, ships and airplanes. Unfortunately, their use nearly unavoidably leads to the emission of carbon dioxide into the atmosphere. Unless an equivalent amount is removed from the air, the carbon dioxide will accumulate and significantly contribute to the man-made greenhouse effect. If fuels are made from biomass, the capture of carbon dioxide is a natural part of the cycle. Here, we discuss technical options for capturing carbon dioxide at much faster rates. We outline the basic concepts, discuss how such capture technologies could be made affordable and show how they could be integrated into a larger system approach. In the short term, the likely source of the hydrocarbon fuels is oil or gas; in the longer term, technologies that can provide energy to remove oxygen from carbon dioxide and water molecules and combine the remaining components into liquid fuels make it possible to recycle carbon between fuels and carbon dioxide in an entirely abiotic process. Here we focus on renewable and nuclear energy options for producing liquid fuels and show how air capture combined with fuel synthesis could be more economic than a transition to electric cars or hydrogen-fueled cars.
Supporting Information Unexpected Role of Activated Carbon in Promoting
Huang, Ching-Hua
Supporting Information Unexpected Role of Activated Carbon in Promoting Transformation of Secondary. Activated Carbons, Modifications and Characterization. The suite of activated carbon particles and fibers), (ii) coconut shell-based activated carbons: Prominent Systems carbon (PSC) from Prominent Systems Inc
TYPE Ia SUPERNOVA CARBON FOOTPRINTS
Thomas, R. C.; Nugent, P. [Computational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94611 (United States); Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Hsiao, E. Y.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Antilogus, P.; Bongard, S.; Canto, A. [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05 (France); Baltay, C. [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States); Buton, C.; Kerschhaggl, M.; Kowalski, M.; Paech, K. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622 Lyon (France); and others
We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II {lambda}6580 absorption 'notches' in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s{sup -1}) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22{sup +10}{sub -6%} of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II {lambda}6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a 'carbon blobs' hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.
Type Ia Supernova Carbon Footprints
NASA Astrophysics Data System (ADS)
Thomas, R. C.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Gangler, E.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Loken, S.; Nugent, P.; Paech, K.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Rubin, D.; Runge, K.; Scalzo, R.; Smadja, G.; Tao, C.; Weaver, B. A.; Wu, C.; Brown, P. J.; Milne, P. A.; Nearby Supernova Factory
We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II ?6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s-1) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22+10 - 6% of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II ?6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a "carbon blobs" hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.
Dopamine as a Carbon Source: The Controlled Synthesis of Hollow Carbon Spheres and Yolk-Structured Carbon Nanocomposites
Dai, Sheng [ORNL; Liu, Rui [ORNL; Mahurin, Shannon Mark [ORNL; Li, Chen [ORNL; Unocic, Raymond R [ORNL; Idrobo Tapia, Juan C [ORNL; Gao, Hongjun [ORNL; Pennycook, Stephen J [ORNL
A facile and versatile synthesis using dopamine as a carbon source gives hollow carbon spheres and yolk-shell Au{at}Carbon nanocomposites. The uniform nature of dopamine coatings and their high carbon yield endow the products with high structural integrity. The Au{at}C nanocomposites are catalytically active.
Carbon dioxide hydrate particles for ocean carbon sequestration
Chow, A.C.
This paper presents strategies for producing negatively buoyant CO[subscript 2] hydrate composite particles for ocean carbon sequestration. Our study is based on recent field observations showing that a continuous-jet ...
Carbon foam characterization tensile evaluation of carbon foam ligamentsĀ
Verdugo Rodriguez, Rogelio Alberto
A methodology for ligament isolation and specimen preparation for tensile testing of single ligaments from the unit cell of open-cell carbon foams has been successfully developed and implemented. Results are presented for ...
Carbon-carbon composites: Emerging materials for hypersonic flight
NASA Technical Reports Server (NTRS)
Maahs, Howard G.
An emerging class of high temperature materials called carbon-carbon composites are being developed to help make advanced aerospace flight become a reality. Because of the high temperature strength and low density of carbon-carbon composites, aerospace engineers would like to use these materials in even more advanced applications. One application of considerable interest is as the structure of the aerospace vehicle itself rather than simply as a protective heat shield as on Space Shuttle. But suitable forms of these materials have yet to be developed. If this development can be successfully accomplished, advanced aerospace vehicles such as the National Aero-Space Plane (NASP) and other hypersonic vehicles will be closer to becoming a reality. A brief definition is given of C-C composites. Fabrication problems and oxidation protection concepts are examined. Applications of C-C composites in the Space Shuttle and in advanced hypersonic vehicles as well as other applications are briefly discussed.
Carbon dioxide solubility and carbon isotope fractionation in basaltic melt
Mattey, D.P. (Univ. of London, Egham Hill (United Kingdom) Univ. of Tasmania, Hobart (Australia))
Carbon dioxide solubility and isotope fractionation data for a MORB composition at 1,200-1,400C and 5-20 kbar have been obtained using piston-cylinder apparatus and stepped-heating mass spectrometry. Carbon dioxide solubility in basalt melt at 5, 10 and 20 kbar is 0.15-0.17%, 0.45-0.51%, and 1.49%, respectively. Values for {Delta}Co{sub 2}(vap) - CO 2/3{sup {minus}} (basalt melt), obtained from the difference between the isotopic compositions for coexisting vapor and melt, vary from 1.8% to 2.2%. A review of measured and estimated values for carbon isotope fractionation between CO{sub 2} vapor and carbon dissolved in basic melts shows variation from 1.8% to 4.6%. Results of this study and other considerations favor relatively small equilibrium CO{sub 2} vapor melt fractionation factors around 2%.
Atmospheric carbon dioxide and the global carbon cycle
Trabalka, J R [ed.
This state-of-the-art volume presents discussions on the global cycle of carbon, the dynamic balance among global atmospheric CO2 sources and sinks. Separate abstracts have been prepared for the individual papers. (ACR)
Measuring supply chain carbon efficiency : a carbon label framework
Craig, Anthony (Anthony J.)
In the near term, efficiency improvements represent a key option for reducing the impacts of climate change. The growing awareness of climate change has increased the attention regarding the carbon emissions "embedded" in ...
Carbon films produced from ionic liquid carbon precursors
Dai, Sheng; Luo, Huimin; Lee, Je Seung
The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X.sup.+a).sub.x(Y.sup.-b).sub.y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that ax=by, and at least one of X.sup.+ and Y.sup.- possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.
Current and relic carbon using natural abundance carbon-13
layse,MF; Clapp,CE; Allmaras,RR; Linden,D.R; Molina, JAE.; Copeland,SM; Dowdy,RH
The role of agricultural practices on soil carbon (C) dynamics is critical to improved soil management. The main objective was to examine the C interactions resulting from crop changes under different tillage and residue treatments.
Reversible Photoswitching of Carbon Dots.
Khan, Syamantak; Verma, Navneet Chandra; Gupta, Abhishek; Nandi, Chayan Kanti
We present a method of reversible photoswitching in carbon nanodots with red emission. A mechanism of electron transfer is proposed. The cationic dark state, formed by the exposure of red light, is revived back to the bright state with the very short exposure of blue light. Additionally, the natural on-off state of carbon dot fluorescence was tuned using an electron acceptor molecule. Our observation can make the carbon dots as an excellent candidate for the super-resolution imaging of nanoscale biomolecules within the cell. PMID:26078266
Seventh International Carbon Dioxide Conference
NSDL National Science Digital Library
Organized by NOAA's Climate Monitoring and Diagnostic Laboratory (CMDL), the Seventh International Carbon Dioxide Conference is planned September 25-30 in Broomfield, Colo. At this website, scientists involved in various aspects of the global carbon cycle, especially the current increases of carbon dioxide in the atmosphere, are encouraged to attend. Users can read the preliminary announcement and can learn about the themes of the conference. Researchers can learn about abstract submissions and accommodations. The Brief Conference History link offers a nice synopsis of the accomplishments of past conferences.
The Orbiting Carbon Observatory (OCO)
NASA Technical Reports Server (NTRS)
Miller, Charles E.
CO2 is the principal human generated driver of climate change. Accurate forecasting of future climate requires an improved understanding of the global carbon cycle and its interaction with the climate system. The Orbiting Carbon Observatory (OCO) will make global, space-based observations of atmospheric CO2 with the precision, resolution, and coverage needed to understand sources and sinks. OCO data will provide critical information for decision makers including the scientific basis for policy formulation, guide for carbon management strategies and treaty monitoring.
Aluminum-carbon composite electrode
Farahmandi, C. Joseph (Auburn, AL); Dispennette, John M. (Auburn, AL)
A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.
Carbon suboxide in Comet Halley?
NASA Technical Reports Server (NTRS)
Huntress, Wesley T., Jr.; Allen, Mark; Delitsky, Mona
The extremely dark nucleus of Comet Halley suggests that its volatile ices contain a few percent of carbonaceous material in the form of graphitic or amorphous carbon. The very high abundance of light elements in the coma dust and the emission feature near 3.4 microns further suggest the presence of a significant organic component, although the identified carbon-containing materials' parent species cannot account for all of such a component. It is presently proposed that an additional contribution from carbon suboxide can account for these observational data, assuming a production rate about 0.03-0.04 times that of water.
Reversible Photoswitching of Carbon Dots
Khan, Syamantak; Verma, Navneet Chandra; Gupta, Abhishek; Nandi, Chayan Kanti
We present a method of reversible photoswitching in carbon nanodots with red emission. A mechanism of electron transfer is proposed. The cationic dark state, formed by the exposure of red light, is revived back to the bright state with the very short exposure of blue light. Additionally, the natural on-off state of carbon dot fluorescence was tuned using an electron acceptor molecule. Our observation can make the carbon dots as an excellent candidate for the super-resolution imaging of nanoscale biomolecules within the cell. PMID:26078266
Carbon dioxide-methane mixture adsorption on activated carbon
V. Goetz; O. Pupier; A. Guillot
In this work, we report new experimental data of pure and binary adsorption equilibria of carbon dioxide and methane on the\\u000a activated carbon RB2 at 273 and 298 K. The pressure range studied were 0¢3.5 MPa for pure gases and 0¢0.1 MPa for mixtures.\\u000a The combination of the generalized Dubinin model to describe the pure CO2 and CH4 isotherms with
On the isotopic composition of carbon in soil carbon dioxide
T. E. Cerling; D. K. Solomon; J. Quade; J. R. Bowman
In this study it is shown that the isotopic composition of carbon in soil CoŌ differs from the isotopic composition of carbon in soil-respired COŌ. Soil COŌ collected from a montane soil has an endmember ╬┤┬╣┬│C value of -23.3% whereas soil-respired COŌ in this system has a ╬┤┬╣┬│C value of -27.5%. This difference is very close to the theoretical difference
Carbon export from continental shelves, denitrification and atmospheric carbon dioxide
John P. Christensen
To investigate the long-term role of continental shelves, a global carbon ? model which included continental shelf waters and sediments, ocean surface waters, the deep-sea and the atmosphere was constructed. With nitrogen limiting oceanic primary production, the model included balanced nitrogen inputs (from the continents and atmosphere) and losses (primarily via denitrification). Carbon export to the deep-sea (without deposition or
Acoustic fatigue characterization of carbon/carbon panels
NASA Technical Reports Server (NTRS)
Rizzi, S. A.; Clevenson, S. A.; Daniels, E. F.
Data from a sonic fatigue test of a blade-stiffened carbon/carbon panel is analyzed to determine the progression of damage to failure. The reduction in stiffness, as observed from acceleration measurements taken during the test, is correlated with the physical damage. Damage was measured through visual inspection, thermographic measurements, and through the novel use of vibration data collected using a scanning laser vibrometer.
Carbon-Carbon Composite Materials for Friction Purposes
Igor V. Gurin; I. M. Neklyudov; S. G. Fursov
Results of studies presented are aimed at developing brake disks for aeroplanes, automobiles, and other spheres of application using thermal-gradient gas-phase methods for compaction. An equation is suggested making it possible to calculate the maximum final density of carbon-carbon composite materials prepared by thermal-gradient gas-phase methods, in relation to the specific content and density of the filler. Results are given
As-Fabricated Reinforced Carbon/Carbon Characterized
NASA Technical Reports Server (NTRS)
Jacobson, Nathan S.; Calomino, Anthony M.; Webster, Neal
Reinforced carbon/carbon (RCC) is a critical material for the space shuttle orbiter. It is used on the wing leading edge and the nose cap, where maximum temperatures are reached on reentry. The existing leading-edge system is a single-plate RCC composite construction with a wall thickness of approximately 1/4 in., making it a prime reliant protection scheme for vehicle operation.
Oxidation microstructure studies of reinforced carbon\\/carbon
Nathan S. Jacobson; Donald M. Curry
Laboratory oxidation studies of reinforced carbon\\/carbon (RCC) are discussed with particular emphasis on the resulting microstructures. This study involves laboratory furnace (500¢1500░C) and arc-jet exposures (1538░C) on various forms of RCC. RCC without oxidation protection oxidized at 800 and 1100░C exhibits pointed and reduced diameter fibers, due to preferential attack along the fiber edges. The 800░C sample showed uniform attack,
Oxidation protective multilayer coatings for carbon¢carbon composites
F. Smeacetto; M. Salvo; M. Ferraris
An oxidation protective double layered coating was deposited on a carbon¢carbon composite (C\\/C) using a simple and low cost method. A surface modification of the C\\/C was obtained by direct reaction of liquid silicon with the C\\/C, promoting the formation of a 5¢10 ?m ?-SiC layer on the composite surface. The inner layer, in contact with the C\\/C, is a
Pyrolytic carbon nanotubes from vapor-grown carbon fibers
Morinobu Endo; Kenji Takeuchi; Kiyoharu Kobori; Katsushi Takahashi; Harold W. Kroto; A. Sarkar
The structure of as-grown and heat-treated pyrolytic carbon nanotubes (PCNTs) produced by hydrocarbon pyrolysis are discussed on the basis of a possible growth process. The structures are compared with those of nanotubes obtained by the arc method (ACNT; arc-formed carbon nanotubes). PCNTs, with and without secondary pyrolytic deposition (which results in diameter increase) are found to form during pyrolysis of
Carbon isotopes in biological carbonates: Respiration and photosynthesis
McConnaughey, T.A.; Burdett, J.; Whelan, J.F.; Paull, C.K.
Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals, and chemoautotrophic and methanotrophic pelecypods. Literature data from fish otoliths and bird and mammal shell and bone carbonates are also considered. Environmental CO2/O2 ratios appear to be the major controlling variable. Atmospheric CO2/O2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO2 in the course of obtaining O2. Tissue CO2 therefore, does not isotopically equilibrate with environmental CO2 as thoroughly in air breathers as in aquatic animals, and this is reflected in skeletal carbonates. Animals having efficient oxygen transport systems, such as vertebrates, also accumulate more respired CO2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO2 uptake is several times faster than respiratory CO2 release. Photosynthesis, therefore, affects skeletal ??13C more strongly than does respiration. Corals also illustrate how "metabolic" effects on skeletal isotopic composition can be estimated, despite the presence of much larger "kinetic" isotope effects. Copyright ?? 1997 Elsevier Science Ltd.
Engineering carbon materials from the hydrothermal carbonization process of biomass.
Hu, Bo; Wang, Kan; Wu, Liheng; Yu, Shu-Hong; Antonietti, Markus; Titirici, Maria-Magdalena
Energy shortage, environmental crisis, and developing customer demands have driven people to find facile, low-cost, environmentally friendly, and nontoxic routes to produce novel functional materials that can be commercialized in the near future. Amongst various techniques, the hydrothermal carbonization (HTC) process of biomass (either of isolated carbohydrates or crude plants) is a promising candidate for the synthesis of novel carbon-based materials with a wide variety of potential applications. In this Review, we will discuss various synthetic routes towards such novel carbon-based materials or composites via the HTC process of biomass. Furthermore, factors that influence the carbonization process will be analyzed and the special chemical/physical properties of the final products will be discussed. Despite the lack of a clear mechanism, these novel carbonaceous materials have already shown promising applications in many fields such as carbon fixation, water purification, fuel cell catalysis, energy storage, CO(2) sequestration, bioimaging, drug delivery, and gas sensors. Some of the most promising examples will also be discussed here, demonstrating that the HTC process can rationally design a rich family of carbonaceous and hybrid functional carbon materials with important applications in a sustainable fashion. PMID:20217791
Rapid oxidation/stabilization technique for carbon foams, carbon fibers and C/C composites
Tan, Seng; Tan, Cher-Dip
An enhanced method for the post processing, i.e. oxidation or stabilization, of carbon materials including, but not limited to, carbon foams, carbon fibers, dense carbon-carbon composites, carbon/ceramic and carbon/metal composites, which method requires relatively very short and more effective such processing steps. The introduction of an "oxygen spill over catalyst" into the carbon precursor by blending with the carbon starting material or exposure of the carbon precursor to such a material supplies required oxygen at the atomic level and permits oxidation/stabilization of carbon materials in a fraction of the time and with a fraction of the energy normally required to accomplish such carbon processing steps. Carbon based foams, solids, composites and fiber products made utilizing this method are also described.
Carbon dioxide recovery by vacuum swing adsorption
Cheng-Tung Chou; Chao-Yuh Chen
According to an investigation by the Intergovernmental Panel on Climate Change (IPCC), carbon dioxide is the most significant greenhouse gas produced as a result of human activities. The amount of carbon dioxide emissions has to be reduced to meet global treaty. The concentration and recovery of carbon dioxide from flue gases is the first important step in solving the carbon
Biochar and Carbon Sequestration: A Regional Perspective
Everest, Graham R
Biochar and Carbon Sequestration: A Regional Perspective A report prepared for East of England #12;Low Carbon Innovation Centre Report for EEDA Biochar and Carbon Sequestration: A Regional Perspective 20/04/2009 ii Biochar and Carbon Sequestration: A Regional Perspective A report prepared for East
Production of activated carbons from Illinois coals
E. J. Hippo; Jian Sun
Although the predominant use of coal is for combustion applications, more beneficial, reasonable and profitable uses may be as a resource for the production of chemicals, and materials, including activated carbon. Activated carbons represent a family of carbonaceous substances manufactured by processes that develop the carbon`s adsorptive properties. The primary objective of this study was to demonstrate that an activated
Irradiation-induced phenomena in carbon
Krasheninnikov, Arkady V.
Chapter 1 Irradiation-induced phenomena in carbon nanotubes To appear in "Chemistry of email@example.com 1 #12;2CHAPTER 1. IRRADIATION-INDUCED PHENOMENA IN CARBON NANOTUBES #12;Contents 1 Irradiation-induced phenomena in carbon nanotubes 1 1.1 Introduction
Superhard diamondlike carbon: preparation, theory, and properties
Wei, Qiuming
One of the many forms of carbon, diamondlike length.6 The ionicity parameter I accounts for thecarbon (DLC bonded carbon atoms. If properly prepared, DLC can have properties that pared with the carbonŁcarbon bond 60 are expected to properties of DLC stem from the continuous rigid have higher bulk modulus
1, 367392, 2004 The carbon budget of
Paris-Sud XI, Universitķ de
have been made to investigate, understand and quantify the global carbon cycle, since the greenhouse to understand and assess the ocean's role in the global carbon cycle. Evidence has been provided that the atmo in the global carbon cycle by linking the terrestrial, oceanic and atmospheric carbon reservoirs (Gattuso et al
Hurricane impacts on US forest carbon sequestration
Steven G McNulty
Recent focus has been given to US forests as a sink for increases in atmospheric carbon dioxide. Current estimates of US forest carbon sequestration average approximately 20 Tg (i.e. 1012 g) year. However, predictions of forest carbon sequestration often do not include the influence of hurricanes on forest carbon storage. Intense hurricanes occur two out of three years across the
Measuring Carbon Sequestration in Pasture Soils
Technology Transfer Automated Retrieval System (TEKTRAN)
Conversion of croplands to pasture can greatly increase sequestration of carbon in soil organic matter, removing carbon dioxide from the atmosphere and helping to reduce the impacts of climate change. The measurement of soil carbon, and its limitations, could impact future carbon credit programs. ...
Soren Anderson; Richard Newell
Carbon capture and storage (CCS) technologies remove carbon dioxide from flue gases for storage in geologic formations or the ocean. We find that CCS is technically feasible, with current costs of about $200 to $250 per ton of carbon. Although currently a relatively expensive mitigation option, CCS could be attractive if we have a stringent carbon policy, if CCS turns
Prospects for Carbon Capture and Storage Technologies
Richard Newell; Soren Anderson
Carbon capture and storage (CCS) technologies remove carbon dioxide from flue gases for storage in geologic formations or the ocean. We find that CCS is technically feasible and economically attractive within the range of carbon policies discussed domestically and internationally. Current costs are about $200 to $250 per ton of carbon, although costs are sensitive to fuel prices and other
Fundamental transmitting properties of carbon nanotube antennas
G. W. Hanson
Fundamental properties of dipole transmitting antennas formed by carbon nanotubes are investigated. Since carbon nanotubes can be grown to centimeter lengths, and since they can be metallic, the properties of carbon nanotubes as antenna elements are of fundamental interest. In this paper, dipole carbon nanotube antennas are investigated via a classical Hallen's-type integral equation, based on a quantum mechanical conductivity.
THE ARGILLIC HORIZON AND DOMINANT CARBONATE STAGE Map Units With More Than One Stage I,III (3,794 - 2) III,IV (20,778 - 12) Argillic horizon and stage I carbonate (13,769 - 8) Argillic horizon and stage II carbonate (1,641 - 1) Argillic horizon and stage III carbonate (26,565 - 14) Argillic horizon
Internal manifolded molten carbonate fuel cell stack
L. G. Marianowski; R. J. Petri
This patent describes an improvement in a generally rectangular molten carbonate fuel cell stack. It comprises: a molten carbonate fuel cell units, each the fuel cell unit comprising an anode and a cathode, an alkali metal carbonates electrolyte in contact with one side of the anode and an alkali metal carbonates electrolyte in contact with an opposite facing side of
Palladium- and Nickel-Catalyzed Carbon¢Carbon Bond Insertion Reactions with Alkylidenesilacyclopropanes
Buchner, Kay M.; Woerpel, K. A.
Palladium and nickel catalysts promoted highly selective carbon¢carbon bond insertion reactions with di-tert-butyl-alkylidenesilacyclopropanes. Pd(PPh3)4 was demonstrated to be the optimal catalyst, allowing for a variety of carbon¢carbon ?-bond insertion reactions. Depending on the nature of the carbon¢carbon ? bond, the insertion reaction proceeded with either direct insertion into the carbon(sp2)¢silicon bond or with allylic transposition. Ring-substituted alkylidenesilacyclopropanes required a nickel catalyst to afford insertion products. Using Ni(cod)2 as the carbon¢carbon bond insertion catalyst, new double alkyne insertion products and alkene isomerization products were observed. PMID:20419110
Molecular Structure of Carbon Suboxide
NSDL National Science Digital Library
Carbon Suboxide is a foul-smelling, lachrymatory gas produced by the dehydration of malonic acid, CH2(COOH)2, with P4O10. It is a stable molecule at -78░ C, but at 25░ C the compound is unstable and it polymerizes to form highly colored solid products. Under the influence of ultraviolet light (in the process known as photolysis), C3O2 decomposes to form the very reactive molecule ketene, C2O. Since carbon suboxide is the acid anhydride of malonic acid, it reacts slowly with water to produce that acid. In the laboratory, carbon suboxide, is widely used as a source of atomic carbon. As a gas it can be stored in a bulb at a pressure of a few mm Hg, but under conditions of standard temperature and pressure (300 K, 1 atm), C3O2 forms a yellow, red, or brown polymer.
NASA Satellite Sees Carbon Dioxide
NSDL National Science Digital Library
In this problem set, learners will analyze a map of atmospheric carbon dioxide derived from satellite data. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.
Increasing carbon nanotube forest density
McCarthy, Alexander P
The outstanding mechanical, electrical, thermal, and morphological properties of individual carbon nanotubes (CNTs) open up exciting potential applications in a wide range of fields. One such application is replacing the ...
Carbon nanotube stabilized conductive polymers
NASA Astrophysics Data System (ADS)
Li, Yi-Fan; Wong, I.-Sing; Lai, Tao-Cheng; Chin, Wei; Hsu, Wen-Kuang
Carbon nanotubes act as radical scavengers in UV-irradiated conductive polymer (poly3,4-ethylenedioxythiophene:polystyrene sulfonate) and effect is verified by conductivity, electron paramagnetic resonance, and infrared absorption data.
Ecologically, petrochemical wastes constitute a major hazard since waste materials contain relatively large amounts of non-biodegradable and toxic materials which may be discharged continuously. A three-part experimental study of activated carbon adsorption and thermal regenerati...
Carbon nanotubes: Captured on camera
NASA Astrophysics Data System (ADS)
Graham, Matt W.
Images of individual carbon nanotubes with their respective optical spectra for chirality characterization are acquired directly on devices and growth substrates using a reflective polarized light microscopy set-up.
Emerging Applications of Carbon Nanotubes
Schnorr, Jan Markus
On the basis of their unique electrical and mechanical properties, carbon nanotubes (CNTs) have attracted great attention in recent years. A diverse array of methods has been developed to modify CNTs and to assemble them ...
Holcombe, Cressie E. (Knoxville, TN); Masters, David R. (Knoxville, TN); Pfeiler, William A. (Norris, TN)
An induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of carbon free materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloy. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an RF induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650.degree. C. for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.
Carbon nanoscrolls by pyrolysis of a polymer
NASA Astrophysics Data System (ADS)
Yadav, Prasad; Warule, Sambhaji; Jog, Jyoti; Ogale, Satishchandra
3D network of carbon nanoscrolls was synthesized starting from pyrolysis of poly(acrylic acid-co-maleic acid) sodium salt. It is a catalyst-free process where pyrolysis of polymer leads to formation of carbon form and sodium carbonate. Upon water soaking of pyrolysis product, the carbon form undergoes self-assembly to form carbon nanoscrolls. The interlayer distance between the walls of carbon nanoscroll was found to be 0.34 nm and the carbon nanoscrolls exhibited a surface area of 188 m2/g as measured by the BET method.
Mechanistical studies on the formation of carbon dioxide in extraterrestrial carbon monoxide ice analog samples
Kaiser, Ralf I.
Mechanistical studies on the formation of carbon dioxide in extraterrestrial carbon monoxide ice with extraterrestrial, carbon monoxide bearing ices. The chemical modifications were monitored on line and in situ via of carbon monoxide and on the formation of carbon dioxide in extraterrestrial ice analog samples. 1
Potential impacts of carbon taxes on carbon flux in western Oregon private forests
Eun Ho Im; Darius M. Adams; Gregory S. Latta
This study considers a carbon tax system as a policy tool for encouraging carbon sequestration through modification of management in existing forests and examines its welfare impacts and costs of the carbon sequestered. The simulated carbon tax leads to reduced harvest and increased carbon stock in the standing trees and understory biomass. Changes in the level of silvicultural investments vary
Untangling the formation of the cyclic carbon trioxide isomer in low temperature carbon dioxide ices
Kaiser, Ralf I.
Untangling the formation of the cyclic carbon trioxide isomer in low temperature carbon dioxide of the cyclic carbon trioxide isomer, CO3(X 1 A1), in carbon-dioxide-rich extraterrestrial ices and in the atmospheres of Earth and Mars were investigated experimentally and theoretically. Carbon dioxide ices were
Preparation, characterization, and application of activated carbon membrane with carbon whiskers
S. D. Bae; C. W. Lee; L. S. Kang; A. Sakoda
A novel activated carbon membrane with carbon whiskers (W-ACM) for wastewater and drinking water treatments was designed and prepared. This membrane has carbon whiskers on its surface for preventing the deposition and accumulation of particles and has activated carbon layer below its carbon whiskers for the adsorption of dissolved organics. Adsorption capacity of the membrane was compared with a granular
Royal College of Art Carbon Management Programme Carbon Management Plan working with
Subramanian, Sriram
, saving resources for our core activities. The development of this Carbon Management Plan not only commitsRoyal College of Art Carbon Management Programme Carbon Management Plan working with Page 1 Royal College of Art Carbon Management Programme Carbon Management Plan (CMP) Date: 25 February 2011 Final
Protein carbon content evolves in response to carbon availability and may influence
Wagner, Andreas
Protein carbon content evolves in response to carbon availability and may influence the fate that ancestral yeast strains preferentially express proteins with low carbon content during carbon limitation, relative to strains selected in the laboratory under carbon limitation. The likely reason
Endohedral Carbon Chains in Single-Wall Carbon Nanotubes R. K. Vadapalli
Mintmire, John W.
Endohedral Carbon Chains in Single-Wall Carbon Nanotubes R. K. Vadapalli and J. W. Mintmire of endohedral linear carbon chains. In these calculations, all-carbon nanowire structures were constructed by inserting cumulenic linear carbon chains inside the semiconducting (7,3) and metallic (7,4) single
Analytical relationships between atmospheric carbon dioxide, carbon emissions, and ocean processes
Follows, Mick
Analytical relationships between atmospheric carbon dioxide, carbon emissions, and ocean processes), Analytical relationships between atmospheric carbon dioxide, carbon emissions, and ocean processes, Global Biogeochem. Cycles, 22, GB3030, doi:10.1029/2008GB003184. 1. Introduction [2] Atmospheric carbon dioxide
Mar., 1955 GASIFICATIONOF CARBONRODSWITH CARBONDIOXIDE 241 GASIFICATION OF CARBON RODS WITH CARBON DIOXIDE1*2
commercial carbons and their gasification rates with carbon dioxide at a series of temperatures between 900 2' of the desired value. The carbon dioxide flow rate through the reactor was maintained constantMar., 1955 GASIFICATIONOF CARBONRODSWITH CARBONDIOXIDE 241 GASIFICATION OF CARBON RODS WITH CARBON
Modeling the selectivity of activated carbons for efficient separation of hydrogen and carbon dioxide
Wu, Jianzhong
the separation of hydrogen and carbon dioxide via adsorption in activated carbons. In the simulations, both hydrogen and carbon dioxide molecules are modeled as Lennard-Jones spheres, and the activated carbons essentially no preference over the two gases and the selectivity of carbon dioxide relative to hydrogen falls
Deoiled asphalt as carbon source for preparation of various carbon materials by chemical vapor deposition
Xuguang Liu; Yongzhen Yang; Xian Lin; Bingshe Xu; Yan Zhang
Various carbon materials, including vapor grown carbon fibers (VGCFs) and carbon trees, were synthesized by chemical vapor deposition in argon atmosphere, using deoiled asphalt as carbon source and ferrocene as catalyst. Pure carbon microbeads (CMBs) were also obtained by this method in the absence of ferrocene. The influence of different growth parameters, such as ferrocene content, reaction temperature, retention time
Hydrogen storage on chemically activated carbons and carbon nanomaterials at high pressures
M. Jordß-Beneyto; F. Sußrez-GarcĒa; D. Lozano-Castell¾; D. Cazorla-Amor¾s; A. Linares-Solano
Hydrogen adsorption measurements have been carried out at different temperatures (298K and 77K) and high pressure on a series of chemically activated carbons with a wide range of porosities and also on other types of carbon materials, such as activated carbon fibers, carbon nanotubes and carbon nanofibers. This paper provides a useful interpretation of hydrogen adsorption data according to the
Carbon 40 (2002) 12491254 Oxidation protection of carbon materials by acid phosphate
Chung, Deborah D.L.
materials (polycrystalline graphite and pitch-based carbon fiber), as shown by weight measurement in air up Science Ltd. All rights reserved. Keywords: A. Carbon fibers, Synthetic graphite; B. Oxidation carbon fibers, provides oxidation protection in a lower temperature range carbonŁcarbon composites
Carbonate rock depositional models: A microfacies approach
Carozzi, A.V.
Carbonate rocks contain more than 50% by weight carbonate minerals such as calcite, dolomite, and siderite. Understanding how these rocks form can lead to more efficient methods of petroleum exploration. Micofacies analysis techniques can be used as a method of predicting models of sedimentation for carbonate rocks. Micofacies in carbonate rocks can be seen clearly only in thin sections under a microscope. This section analysis of carbonate rocks is a tool that can be used to understand depositional environments, diagenetic evolution of carbonate rocks, and the formation of porosity and permeability in carbonate rocks. The use of micofacies analysis techniques is applied to understanding the origin and formation of carbonate ramps, carbonate platforms, and carbonate slopes and basins. This book will be of interest to students and professionals concerned with the disciplines of sedimentary petrology, sedimentology, petroleum geology, and palentology.
Kevlar and carbon composites compared
Demmler, A.W.
Characteristics of advanced composites are investigated. The fibers considered are Kevlar and carbon. The greatest advantage of composites over metals is emphasized, and lies in their permitting designers to obtain properties in exactly the locations desired. Kevlar replaced S-glass on the Trident 2 missile, saving 800 lbs. and adding 800 miles to its range. Military aircraft builders find that advanced carbon composites more often than not win out over Kevlar.
Carbon storage in Amazonian podzols
NASA Astrophysics Data System (ADS)
Montes, Celia; Lucas, Yves; Pereira, Osvaldo; Merdy, Patricia; Santin, Roberta; Ishida, Dķbora; du Gardin, Beryl; Melfi, Adolpho
It has recently been discovered that Amazonian podzols may store much larger quantities of carbon than previously thought, particularly in their deep Bh horizons (over 13.6 Pg for Brazilian Amazonia alone [1]). Similarly high carbon stocks are likely to exist in similar climate/soil areas, mainly in Africa and in Borneo. Such carbon stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, which is likely to affect organic matter turnover in soils. The direction of the change, however, is not clear and is likely to depend on the specific conditions of carbon storage and properties of the soils. It is reasonable to assume that the drying of the Bh horizons of equatorial podzols, which are generally saturated, will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. These unknowns resulted in research programs, granted by the Brazilian FAPESP and the French Rķgion PACA-ARCUS and ANR, dedicated improving estimates of the Amazonian podzol carbon stocks and to an estimate of its mineralisability. Eight test areas were determined from the analysis of remote sensing data in the larger Amazonian podzol region located in the High Rio Negro catchment and studied in detail. Despite the extreme difficulties in carrying out the field work (difficulties in reaching the study sites and extracting the soils), more than a hundred points were sampled. In all podzols the presence of a thick deep Bh was confirmed, sometimes to depths greater than 12 m. The Bh carbon was quantified, indicating that carbon stocks in these podzols are even higher than estimated recently [1]. References 1- Montes, C.R.; Lucas, Y.; Pereira, O.J.R.; Achard, R.; Grimaldi, M.; Mefli, A.J. Deep plant?derived carbon storage in Amazonian podzols. Biogeosciences, 8, 113?120, 2011.
Carbon nanotubes for optical limiting
L Vivien; P Lanńon; D Riehl; F Hache; E Anglaret
This paper reviews the optical limiting properties of carbon nanotubes. The nonlinear optical properties of nanotubes were investigated in water and in chloroform suspensions. Nonlinear transmittance measurements were reported for various pulse durations and wavelengths and show that carbon nanotubes are good candidates for effective optical limiting over broad temporal and laser energy ranges. Z-Scans and pump-probe time-resolved experiments were
Lithographically defined microporous carbon structures
Burckel, David Bruce; Washburn, Cody M.; Polsky, Ronen; Brozik, Susan M.; Wheeler, David R.
A lithographic method is used to fabricate porous carbon structures that can provide electrochemical electrodes having high surface area with uniform and controllable dimensions, providing enormous flexibility to tailor the electrodes toward specific applications. Metal nanoparticles deposited on the surface of the porous carbon electrodes exhibit ultra small dimensions with uniform size distribution. The resulting electrodes are rugged, electrically conductive and show excellent electrochemical behavior.
Activated carbon to the rescue
Sen, S. [Calgon Carbon Corp., Pittsburgh, PA (United States)
This article describes the response to pipeline spill of ethylene dichloride (EDC) on the property of an oil company. Activated carbon cleanup proceedure was used. During delivery, changeout, transport, storage, thermal reactivation, and return delivery to the site, the carbon never came into direct contact with operating personnel or the atmosphere. More than 10,000 tones of dredge soil and 50 million gallons of surface water were processed during the emergency response.
Thermal Properties of Carbon Nanotubes
Mohamed. Osman; Aron W. Cummings; Deepak Srivastava
The experimental observation of carbon nanotubes by Sumio Iijima in 1991 [1], sparked a significant effort in theoretical\\u000a and experimental investigation of carbon nanotubes and related structures. The studies of thermal properties, although very\\u000a important from fundamental and applications points of view, have received less attention in comparison with other aspects\\u000a such as the electrical and mechanical properties [2¢18]. This
Carbon nanotubes for orthopaedic implants
Rose L. Spear; Ruth E. Cameron
The physical and biological limitations of current orthopaedic implant materials are a major challenge for bone tissue engineering.\\u000a Nanotechnology has introduced new materials and methods for meeting this challenge. The application of nanotechnology to engineering\\u000a new bone substitutes finds a model in the nanoscale components of natural bone tissue. Carbon nanotubes are a macromolecular\\u000a form of carbon with exceptional properties
Combustion processes for carbon capture
Terry F. Wall
A review of the technologies for coal-based power generation closest to commercial application involving carbon capture is presented. Carbon capture and storage (CCS) developments are primarily adaptations of conventional combustion systems, with additional unit operations such as bulk oxygen supply, CO2 capture by sorbents, CO2 compression, and storage. They use pulverized coal combustion in entrained flowŚthe dominant current technology for
Universally dispersible carbon nanotubes.
Prevoteau, Alexandre; Souliķ-Ziakovic, Corinne; Leibler, Ludwik
We show that supramolecular chemistry provides a convenient tool to prepare carbone nanotubes (CNTs) that can be dispersed in solvents of any chemical nature, easily recovered and redispersed. Thymine-modified CNTs (CNT-Thy) can be dispersed in solution in the presence of diaminotriazine (DAT) end-functionalized polymers, through supramolecular Thy/DAT association. DAT-polymer chains are selected according to the solvent chemical nature: polystyrene (PS) for hydrophobic/low polarity solvents and a propylene oxide/ethylene oxide copolymer (predominantly propylene oxide based, PPO/PEO) for polar solvents or water. Long-term stable supramolecular CNT dispersions are reversibly aggregated by adding a few droplets of a selective dissociating agent of the Thy/DAT association (DMSO). CNT-Thy, simply recycled by centrifugation or filtration, can be redispersed in another solvent in presence of a suitable soluble DAT-polymer. Dispersion and aggregation can also be switched on and off by choosing a polymer for which a given solvent is close to ?-conditions, e.g., PS in cyclohexane or PPO/PEO in water. PMID:23171241
Ashley, S.
This article describes improved techniques of resin transfer molding being used to fabricate flight-critical carbon-composite structures for aircraft and jet engines. Hand lay-up methods have been the traditional means to fabricate fiber-reinforced resin-composite parts. The procedure typically involves laying up or stacking multiple plies of preimpregnated woven fabrics in molds, then curing the sealed mold assemblies in autoclaves. The entire process is both time-consuming and labor-intensive. Only in the last few years has resin transfer molding (RTM)--a family of processes in which resin is injected into fiber preforms enclosed in heated mold cavities--emerged as a viable alternative for producing composite parts. RTM can often speed processing because it performs the shaping and curing functions in one step. The method also features the ability (in principle) to achieve precise control of the placement, orientation, and quantity of reinforcing fibers in the formed structure. Thus, RTM lends itself well to the fabrication of highly complex structural shapes that usually pose a challenge to the lay-up method.
Electronic transport in amorphous carbon
Sullivan, J.P.; Friedmann, T.A.
Electronic transport in a-C films has been the subject of considerable debate. In this study, combined stress relaxation and electrical transport studies were used to identify the transport mechanism in a-C films prepared by pulsed-laser deposition. The stress relaxation was modeled by a first-order kinetic reaction involving transformation of 4-fold coordinated carbon atoms to 3-fold coordinated carbon atoms, and the distribution of activation energies for this process was determined. The activation energies were found to range from about 1 eV to over 2 eV, and using these activation energies, the increase in 3-fold carbon concentration with time-temperature annealing was obtained. Conductivity measurements were also performed as a function of time-temperature annealing. It was found that the conductivity of a-C films is exponentially proportional to increases in 3-fold carbon concentration. This result can be explained by thermally activated hopping along carbon 3-fold chains combined with chain-to-chain tunneling. From the data, a typical chain length was estimated to consist of 13 carbon atoms. The heterogeneous nature of the conductivity may explain the spatially localized electron emission which is observed in a-C assuming a tunnel barrier emission model.
VLSI-compatible carbon nanotube doping technique with low work-function metal oxides.
Suriyasena Liyanage, Luckshitha; Xu, Xiaoqing; Pitner, Greg; Bao, Zhenan; Wong, H-S Philip
Single-wall carbon nanotubes (SWCNTs) have great potential to become the channel material for future high-speed transistor technology. However, as-made carbon nanotube field effect transistors (CNFETs) are p-type in ambient, and a consistent and reproducible n-type carbon nanotube (CNT) doping technique has yet to be realized. In addition, for very large scale integration (VLSI) of CNT transistors, it is imperative to use a solid-state method that can be applied on the wafer scale. Herein we present a novel, VLSI-compatible doping technique to fabricate n-type CNT transistors using low work-function metal oxides as gate dielectrics. Using this technique we demonstrate wafer-scale, aligned CNT transistors with yttrium oxide (Y2Ox) gate dielectrics that exhibit n-type behavior with Ion/Ioff of 10(6) and inverse subthreshold slope of 95 mV/dec. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses confirm that slow (?1 ┼/s) evaporation of yttrium on the CNTs can form a smooth surface that provides excellent wetting to CNTs. Further analysis of the yttrium oxide gate dielectric using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques revealed that partially oxidized elemental yttrium content increases underneath the surface where it acts as a reducing agent on nanotubes by donating electrons that gives rise to n-type doping in CNTs. We further confirm the mechanism for this technique with other low work-function metals such as lanthanum (La), erbium (Er), and scandium (Sc) which also provide similar CNT NFET behavior after transistor fabrication. This study paves the way to exploiting a wide range of materials for an effective n-type carbon nanotube transistor for a complementary (p- and n-type) transistor technology. PMID:24628497
Dust to Dust: The Carbon Cycle
NSDL National Science Digital Library
Anderson, Jennifer Y.
This case study examines the carbon cycle: from carbon becoming carbon dioxide, to carbohydrate, to animals, then back to carbon dioxide again. Chemistry topics like atomic structures, carbon isotopes, radiocarbon dating, beta decay, half-life and photosynthesis are explained. The case study and teaching notes may be downloaded in PDF format. The site also includes a section for instructor feedback where general comments may be read and contributed.
Effects of Organic Carbon\\/Carbonate Burial Ratios and Biological Carbon Fixation on the Global Carbon Cycle Over the Past ~200 myr
M. E. Katz; A. J. Milligan; B. S. Cramer; K. Fennel; K. G. Miller; J. D. Wright; P. G. Falkowski
The isotopic composition of the global carbon reservoir integrates large kinetic fractionations from photosynthesis with small thermodynamic fractionations from carbonate precipitation. We present concordant delta 13C records of carbonates (delta 13Ccarb) and organic matter (delta 13Corg), along with new carbonate (Ccarb) and organic carbonate (Corg) fluxes for the past ś205 myrs (Jurassic-Cenozoic) generated from bulk sediment samples from the Atlantic.
Global climate change and pedogenic carbonates
Lal, R.; Kimble, J.M.; Stewart, B.A.; Eswaran, H. [eds.
Global Climate Change summarizes what is known about soil inorganic carbon and develops strategies that could lead to the retention of more carbon in the soil. It covers basic concepts, analytical methods, secondary carbonates, and research and development priorities. With this book one will get a better understanding of the global carbon cycle, organic and inorganic carbon, and their roles, or what is known of them, in the greenhouse effect.
Simple preparation and catalytic activity of Pd particles dispersed mesoporous carbons from poly(VDC/MA) containing Pd and Y compounds.
Tamai, Hisashi; Ogawa, Junichi; Yasuda, Hajime
We report a simple preparation of Pd particles dispersed mesoporous carbons. The carbons were prepared by steam activation of carbonized vinylidene chloride/methyl acrylate copolymer (poly(VDC/MA)) containing yttrium acetylacetonate (Y(acac)(3)) and palladium acetylacetonate (Pd(acac)(2)). The resulting carbons consist of high contents of mesopore and uniformly dispersed fine Pd particles. We measured the catalytic activities of the carbons obtained for hydrogenation of methyl linoleate. The Pd particles dispersed in mesoporous activated carbons obtained from poly(VDC/MA) containing both Y(acac)(3) and Pd(acac)(2) showed high catalytic activities, compared with the microporous activated carbon obtained from poly(VDC/MA) containing only Pd(acac)(2). Especially Pd particles dispersed in mesoporous carbons exhibited excellent selectivity for hydrogenation of diene (methyl linoleate) to monoene (methyl oleate). PMID:12686180
Carbonic Acid Pretreatment of Biomass
G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry
This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid compared to water alone. 6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high (~50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.
Carbonic Acid Retreatment of Biomass
Baylor university
This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid compared to water alone. (6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high ({approx}50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.
A study of the remineralization of organic carbon in nearshore sediments using carbon isotopes
McNichol, Ann P., 1956-
A study of the remineralization of organic carbon was conducted in the organic-rich sediments of Buzzards Bay, MA. Major processes affecting the carbon chemistry in sediments are reflected by changes in the stable carbon ...
Black Carbon in the Soil Carbon Cycle: Is it an Oxidation Resistant End-Product?
Fischlin, Andreas
;1 Introduction Soils represent a large carbon pool in the global carbon cycle. Estimates suggest that this pool is twice as large as the atmospheric pool. But its role in the global carbon cycle remains unclear
Wood, Stephanie
Carbon isotope stratigraphy of carbonate sediments is instrumental in examining major perturbations in the global carbon cycle and in correlating strata. However, the primary isotopic signal recorded in these sediments can vary with depositional...
Carbon accumulation in arid croplands of northwest China: pedogenic carbonate exceeding organic carbon
Wang, Xiujun; Wang, Jiaping; Xu, Minggang; Zhang, Wenju; Fan, Tinglu; Zhang, Juan
Soil carbonate (SIC) exceeds organic carbon (SOC) greatly in arid lands, thus may be important for carbon sequestration. However, field data for quantifying carbonate accumulation have been lacking. This study aims to improve our understanding of SIC dynamics and its role in carbon sequestration. We analyzed two datasets of SOC and SIC and their 13C compositions , one with over 100 soil samples collected recently from various land uses in the Yanqi Basin, Xinjiang, and the other with 18 archived soil samples from a long-term experiment (LTE) in Pingliang, Gansu. The data from the Yanqi Basin showed that SOC had a significant relationship with SIC and pedogenic carbonate (PIC); converting shrub land to cropland increased PIC stock by 5.2?kg C m?2, which was 3.6 times of that in SOC stock. The data from the LTE showed greater accumulation of PIC (21¢49?g C m?2 year?1) than SOC (10¢39?g C m?2 year?1) over 0¢20?cm. Our study points out that intensive cropping in the arid and semi-arid regions leads to an increase in both SOC and PIC. Increasing SOC through straw organic amendments enhances PIC accumulation in the arid cropland of northwestern China. PMID:26091554
Carbon accumulation in arid croplands of northwest China: pedogenic carbonate exceeding organic carbon.
Wang, Xiujun; Wang, Jiaping; Xu, Minggang; Zhang, Wenju; Fan, Tinglu; Zhang, Juan
Soil carbonate (SIC) exceeds organic carbon (SOC) greatly in arid lands, thus may be important for carbon sequestration. However, field data for quantifying carbonate accumulation have been lacking. This study aims to improve our understanding of SIC dynamics and its role in carbon sequestration. We analyzed two datasets of SOC and SIC and their (13)C compositions , one with over 100 soil samples collected recently from various land uses in the Yanqi Basin, Xinjiang, and the other with 18 archived soil samples from a long-term experiment (LTE) in Pingliang, Gansu. The data from the Yanqi Basin showed that SOC had a significant relationship with SIC and pedogenic carbonate (PIC); converting shrub land to cropland increased PIC stock by 5.2?kg C m(-2), which was 3.6 times of that in SOC stock. The data from the LTE showed greater accumulation of PIC (21-49?g C m(-2) year(-1)) than SOC (10-39?g C m(-2) year(-1)) over 0-20?cm. Our study points out that intensive cropping in the arid and semi-arid regions leads to an increase in both SOC and PIC. Increasing SOC through straw organic amendments enhances PIC accumulation in the arid cropland of northwestern China. PMID:26091554
Carbon dioxide sequestration by ex-situ mineral carbonation
O'Connor, W.K.; Dahlin, D.C.; Turner, P.C.; and Walters, R.P.
The process developed for carbon dioxide sequestration utilizes a slurry of water mixed with olivine- forsterite end member (Mg{sub 2}SiO{sub 4}), which is reacted with supercritical CO{sub 2} to produce magnesite (MgCO{sub 3}). Carbon dioxide is dissolved in water to form carbonic acid, which likely dissociates to H{sup +} and HCO{sub 3}{sup -}. The H{sup +} hydrolyzes the silicate mineral, freeing the cation (Mg{sup 2+}), which reacts with the HCO{sub 3}{sup -} to form the solid carbonate. Results of the baseline tests, conducted on ground products of the natural mineral, have demonstrated that the kinetics of the reaction are slow at ambient temperature (22 degrees C) and subcritical CO{sub 2} pressures (below 7.4 MPa). However, at elevated temperature and pressure, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant conversion to the carbonate occurs. Extent of reaction is roughly 90% within 24 h, at 185 degrees C and partial pressure of CO{sub 2} (P{sub CO{sub 2}}) of 11.6 MPa. Current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, and/or solution modification. Subsequent tests are intended to examine these options, as well as other mineral groups.
[Carbon storage and carbon sink of mangrove wetland: research progress].
Zhang, Li; Guo, Zhi-hua; Li, Zhi-yong
Mangrove forest is a special wetland forest growing in the inter-tidal zone of tropical and subtropical regions, playing important roles in windbreak, promoting silt sedimentation, resisting extreme events such as cyclones and tsunamis, and protecting coastline, etc. The total area of global mangrove forests is about 152000 km2, only accounting for 0. 4% of all forest area. There are about 230 km2 mangrove forests in China. The mangrove forests in the tropics have an average carbon storage as high as 1023 Mg hm-2, and the global mangrove forests can sequestrate about 0. 18-0. 228 Pg C a-1. In addition to plant species composition, a variety of factors such as air temperature, seawater temperature and salinity, soil physical and chemical properties, atmospheric CO2 concentration, and human activities have significant effects on the carbon storage and sink ability of mangrove forests. Many approaches based onfield measurements, including allometric equations, remote sensing, and model simulation, are applied to quantify the carbon storage and sink ability of mangrove forest wetland. To study the carbon storage and sink ability of mangrove wetland can promote the further understanding of the carbon cycle of mangrove wetland and related controlling mechanisms, being of significance for the protection and rational utilization of mangrove wetland. PMID:23898678
Tetrahedral bonding in amorphous carbon
NASA Astrophysics Data System (ADS)
McKenzie, D. R.
Electron configurations close to the tetrahedral 0034-4885/59/12/002/img1 hybridization are found in pure amorphous carbon at a concentration which depends on preparation conditions. Tetrahedral bonding at levels of approximately 80% is found in amorphous carbons formed from beams of carbon ions with energies in a `window' between 20 eV and approximately 500 eV. Suitable techniques for its formation include cathodic arc deposition, ion beam deposition and laser ablation. Similar material appears to be formed by pressure treatment of fullerene precursors and by displacement damage in diamond. Highly tetrahedral forms of amorphous carbon (ta-C) show electronic, optical and mechanical properties which approach those of diamond and are quite different from amorphous carbons with low 0034-4885/59/12/002/img1 content. Useful techniques for determining the 0034-4885/59/12/002/img1 content include electron energy loss spectroscopy, electron and neutron diffraction and Raman spectroscopy. Considerable progress has been made in the understanding of this material by simulating its structure in the computer with a range of techniques from empirical potentials to ab initio quantum mechanics. The structure shows departures from an idealized glassy state of diamond which would have a random tetrahedral network structure as used to describe amorphous silicon and germanium. A surprising feature of the structure simulated using ab initio methods is the presence of small rings containing three or four 0034-4885/59/12/002/img1 carbon atoms. The electronic and optical properties are strongly influenced by the residual of 0034-4885/59/12/002/img5 carbon. Applications to electronic devices are at an early stage with the demonstration of photoconductivity and some simple junction devices. Applications as a wear resistant coating are promising, since the theoretically predicted high values of elastic constants, comparable to but less than those of diamond, are achieved experimentally, together with low friction coefficients.
Aerobic dehydrogenative ?-diarylation of benzyl ketones with aromatics through carbon-carbon bond cleavage.
More, Nagnath Yadav; Jeganmohan, Masilamani
Substituted benzyl ketones reacted with aromatics in the presence of K2S2O8 in CF3COOH at room temperature, yielding ?-diaryl benzyl ketones through a carbon-carbon bond cleavage. In the reaction, two new carbon-carbon bonds were formed and one carbon-carbon bond was cleaved. It is very interesting that two different nucleophiles such as benzyl ketones and aromatics were coupled together without metal, which is unusual in organic synthesis. PMID:24479373
Novel method for carbon nanofilament growth on carbon fibers
Phillips, Johathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM MECH.ENG.; Terani, Mehran [UNM MECH.ENG.; Al - Haik, Marwan [UNM MECH.ENG.; Garcia, Daniel [UNM MECH.ENG.; Taha, Mahmoud R [UNM MECH.ENG.
Fiber reinforced structural composites such as fiber reinforced polymers (FRPs) have proven to be key materials for blast mitigation due to their enhanced mechanical performance. However, there is a need to further increase total energy absorption of the composites in order to retain structural integrity in high energy environments, for example, blast events. Research has shown that composite failure in high energy environments can be traced to their relatively low shear strength attributed to the limited bond strength between the matrix and the fibers. One area of focus for improving the strength of composite materials has been to create 'multi-scale' composites. The most common approach to date is to introduce carbon nanotubes into a more traditional composite consisting of epoxy with embedded micron scale fibers. The inclusion of carbon nanotubes (CNT) clearly toughens different matrices. Depositing CNT in brittle matrix increases stiffness by orders of magnitude. Currently, this approach to create multiscale composites is limited due to the difficulty of dispersing significant amounts of nanotubes. It has repeatedly been reported that phase separation occurs above relatively low weight percent loading (ca. 3%) due to the strong van der Waals forces between CNTs compared with that between CNT and polymer. Hence, the nanotubes tend to segregate and form inclusions. One means to prevent nanotube or nanofilament agglomeration is to anchor one end of the nanostructure, thereby creating a stable multi-phase structure. This is most easily done by literally growing the CNTs directly on micron scale fibers. Recently, CNT were grown on carbon fibers, both polyacrylonitrile- (PAN-) and pitch-based, by hot filament chemical vapor deposition (HFCVD) using H2 and CH4 as precursors. Nickel clusters were electrodeposited on the fiber surfaces to catalyze the growth and uniform CNT coatings were obtained on both the PAN- and pitch-based carbon fibers. Multiwalled CNTs with smooth walls and low impurity content were grown. Carbon nanofibers were also grown on a carbon fiber cloth using plasma enhanced chemical vapor deposition (CVD) from a mixture of acetylene and ammonia. In this case, a cobalt colloid was used to achieve a good coverage of nanofibers on carbon fibers in the cloth. Caveats to CNT growth include damage in the carbon fiber surface due to high-temperatures (>800 C). More recently, Qu et al. reported a new method for uniform deposition of CNT on carbon fibers. However, this method requires processing at 1100 C in the presence of oxygen and such high temperature is anticipated to deepen the damage in the carbon fibers. In the present work, multi-scale filaments (herein, linear carbon structures with multi-micron diameter are called 'fibers', all structures with sub-micron diameter are called 'filaments') were created with a low temperature (ca. 550 C) alternative to CVD growth of CNTs. Specifically, nano-scale filaments were rapidly generated (> 10 microns/hour) on commercial micron scale fibers via catalytic (Pd particles) growth from a fuel rich combustion environment at atmospheric pressure. This atmospheric pressure process, derived from the process called Graphitic Growth by Design (GSD), is rapid, the maximum temperature low enough (below 700 C) to avoid structural damage and the process inexpensive and readily scalable. In some cases, a significant and unexpected aspect of the process was the generation of 'three scale' materials. That is, materials with these three size characteristics were produced: (1) micrometer scale commercial PAN fibers, (2) a layer of 'long' sub-micrometer diameter scale carbon filaments, and (3) a dense layer of 'short' nanometer diameter filaments.
Carbon-negative Fuel from Stranded Energy with Carbon Sequestration
NASA Astrophysics Data System (ADS)
van Vechten, James; Graupner, Robert
Stranded energy can be captured as nitrogen based fuels (ammonia, urea, guanidine) produced from hydrogen from saltwater electrolysis. The use of electrodialysis enables the co-production of NaOH(aq) and HCl(aq) together with oxygen and hydrogen. The NaOH can capture atmospheric CO2 as sodium carbonate or sodium bicarbonate and together with HCl and basaltic local rocks can produce a range of valuable commodity chemicals. Depending on the form of the sequestered carbon, either 2 or 4 moles of CO2 can be captured for each mole of hydrogen gas produced. The nitrogen based fuels can be used to power conventional thermal engines or solid oxide fuel cells. They can also be used as fertilizers, thereby avoiding the release of CO2 during their conventional production using natural gas or coal. With care the produced NaOH or carbonates may be used to counter ocean acidification
Carbon Monoxide Hazards from Small Gasoline Powered Engines
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Carbon dioxide sequestration by direct aqueous mineral carbonation
O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.
Carbon dioxide sequestration by an ex-situ, direct aqueous mineral carbonation process has been investigated over the past two years. This process was conceived to minimize the steps in the conversion of gaseous CO2 to a stable solid. This meant combining two separate reactions, mineral dissolution and carbonate precipitation, into a single unit operation. It was recognized that the conditions favorable for one of these reactions could be detrimental to the other. However, the benefits for a combined aqueous process, in process efficiency and ultimately economics, justified the investigation. The process utilizes a slurry of water, dissolved CO2, and a magnesium silicate mineral, such as olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. These minerals were selected as the reactants of choice for two reasons: (1) significant abundance in nature; and (2) high molar ratio of the alkaline earth oxides (CaO, MgO) within the minerals. Because it is the alkaline earth oxide that combines with CO2 to form the solid carbonate, those minerals with the highest ratio of these oxides are most favored. Optimum results have been achieved using heat pretreated serpentine feed material, sodium bicarbonate and sodium chloride additions to the solution, and high partial pressure of CO2 (PCO2). Specific conditions include: 155?C; PCO2=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Future studies are intended to investigate various mineral pretreatment options, the carbonation solution characteristics, alternative reactants, scale-up to a continuous process, geochemical modeling, and process economics.
Theorizing the carbon economy: introduction to the special issue The term `carbon economy'often has an adjective placed nearby: the `new'carbon economy,
of carbon capture and storage and nuclear technologies. These dimensions÷and surface-level to deeperTheorizing the carbon economy: introduction to the special issue The term `carbon economy'often has an adjective placed nearby: the `new'carbon economy, the `low' carbon economy, the carbon `neutral' economy
Torsional Electromechanics of Carbon Nanotubes
NASA Astrophysics Data System (ADS)
Joselevich, Ernesto; Cohen-Karni, Tzahi; Segev, Lior; Srur-Lavi, Onit; Cohen, Sidney R.
Carbon nanotubes are known to be distinctly metallic or semiconducting depending on their diameter and chirality. Here we show that continuously varying the chirality by mechanical torsion can induce conductance oscillations, which can be attributed to metal-semiconductor periodic transitions. The phenomenon is observed in multi-walled carbon nanotubes, where both the torque and the current are shown to be carried predominantly by the outermost wall. The oscillation period with torsion is consistent with the theoretical shifting of the corners of the first Brillouin zone of graphene across different subbands allowed in the nanotube. Beyond a critical torsion, the conductance irreversibly drops due to torsional failure, allowing us to determine the torsional strength of carbon nanotubes. Our experiments indicate that carbon nanotubes could be used as self-sensing torsional springs for nanoelectromechanical systems (NEMS). [1] E. Joselevich, Twisting nanotubes: From torsion to chirality, ChemPhysChem 2006, 7, 1405. [2] T. Cohen-Karni, L. Segev, O. Srur-Lavi, S. R. Cohen, E. Joselevich, Torsional electromechanical quantum oscillations in carbon nanotubes, Nature Nanotechnology, 2006, 1, 36.
Compacted carbon for electrochemical cells
Greinke, Ronald Alfred (Medina, OH); Lewis, Irwin Charles (Strongsville, OH)
This invention provides compacted carbon that is useful in the electrode of an alkali metal/carbon electrochemical cell of improved capacity selected from the group consisting of: (a) coke having the following properties: (i) an x-ray density of at least 2.00 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 47%; and (b) graphite having the following properties: (i) an x-ray density of at least 2.20 grams per cubic centimeters, (ii) a closed porosity of no greater than 5%, and (iii) an open porosity of no greater than 25%. This invention also relates to an electrode for an alkali metal/carbon electrochemical cell comprising compacted carbon as described above and a binder. This invention further provides an alkali metal/carbon electrochemical cell comprising: (a) an electrode as described above, (b) a non-aqueous electrolytic solution comprising an organic aprotic solvent and an electrolytically conductive salt and an alkali metal, and (c) a counterelectrode.
Benzene-derived carbon nanothreads
NASA Astrophysics Data System (ADS)
Fitzgibbons, Thomas C.; Guthrie, Malcolm; Xu, En-Shi; Crespi, Vincent H.; Davidowski, Stephen K.; Cody, George D.; Alem, Nasim; Badding, John V.
Low-dimensional carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered carbon nanomaterials, but despite almost a century of study this approach has produced only amorphous products. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp3 carbon nanomaterial formed by high-pressure solid-state reaction of benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp3-bonded carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp2 carbon nanotubes or conven tional high-strength polymers. They may be the first member of a new class of ordered sp3 nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.
NASA Astrophysics Data System (ADS)
MacGilchrist, G. A.; Naveira Garabato, A. C.; Tsubouchi, T.; Bacon, S.; Torres-Valdķs, S.; Azetsu-Scott, K.
We present observation based estimates of the transport of dissolved inorganic carbon (DIC) across the four main Arctic Ocean gateways (Davis Strait, Fram Strait, Barents Sea Opening and Bering Strait). Combining a recently derived velocity field at these boundaries with measurements of DIC, we calculated a net summertime pan-Arctic export of 231▒49 Tg C yr-1. On an annual basis, we estimate that at least 166▒60 Tg C yr-1 of this is due to uptake of CO2 from the atmosphere, although time-dependent changes in carbon storage are not quantified. To further understand the region's role as a carbon sink, we calculated the volume-conserved net DIC transport from beneath a prescribed mixed layer depth of 50 m, referred to as æinterior transport', revealing an export of 61▒23 Tg C yr-1. Applying a carbon framework to infer the sources of interior transport implied that this export is primarily due to the sinking and remineralisation of organic matter, highlighting the importance of the biological pump. Furthermore, we qualitatively show that the present day Arctic Ocean is accumulating anthropogenic carbon beneath the mixed layer, imported in Atlantic Water.
Hydroburst test of a carbon-carbon involute exit cone
NASA Technical Reports Server (NTRS)
Sullivan, Roy M.
A hydroburst test of the aft portion of the PAM-D exit cone and the test procedure are described in detail. The hydrostatic pressure required to buckle the cone was 9.75 psi. Meanwhile, the PAM-D exit cone was modeled using the finite element method and a theoretical bucking pressure (8.76 psi) was predicted using the SPAR finite element code. The modeling technique employed is discussed. By comparing the theoretical to predicted critical pressures, this report verifies the modeling technique and calculates a material knockdown factor for the carbon-carbon exit cone.
Deciphering Carbon Isotope Excursions in Separated Biogenic and Diagenetic Carbonates
NASA Astrophysics Data System (ADS)
Hermoso, M.; Minoletti, F.; Hesselbo, S.; Jenkyns, H.; Rickaby, R.; Diester-Haass, L.; Delsate, D.
The long-term evolution of the carbon-isotope ratio in the sedimentary archive is classically linked with changes in primary productivity and organic matter burial. There have been sudden and pronounced shifts, so-called Carbon Isotope Excursions (CIEs) in the long-term trends as evidenced by synchronous shifts from various basins. These geochemical perturbations may have various explanations such as changes of the efficiency of the carbon sink; sudden infusion of isotopically-light carbon into the Ocean-Atmosphere system; or advection of 12C-rich source from bottom water in a stratified water column. Beside the record of primary changes in seawater chemistry, a possible diagenetic overprint may also mime such CIEs in the sedimentary record. The aim of this contribution is to illustrate through three critical intervals (the Early Toarcian, the K-P boundary and the Mid-Miocene Montery Event) how the various micron-sized sedimentary particles specifically record these CIEs, which are respectively associated with major paleoceanographical events. New techniques for getting monotaxic calcareous nannofossil assemblages from the sediment (Minoletti et al., accepted) enable the isotopic measurement at various depths within the surface water and from bottom water by analyzing early diagenetic precipitations (rhombs and micarbs). The integration of these high-resolution isotopic signals in terms of amplitudes affords to recognize diagenetic artifacts in some sections displaying coeval decrease in the carbonate content. For both Early Toarcian and K-P events, corroborative records of CIE records in both primary calcite and bottom water carbonate indicate a global C-isotope perturbation of the water column. For the Monterey event, the evolution of calcareous nannoplankton and the foraminifera isotopic records are in overall agreement, but in detail, the coccolith-discoaster and foraminifer ratio in the sediment, related to environmental changes, is likely to produce isotopic shift in the bulk carbonate record. Contrasts in the amplitude of the carbon-isotope excursion at the single-species level compared to inorganic calcite and organic subtrate, should improve our understanding of the evolution of the water column composition through these major C-cycling perturbation events, and how marine calcifiers have fedback during such events, and eventually contribute for better understanding ocean-climate dynamics through time and into the future. Minoletti, F., Hermoso, M. and Gressier, V. (accepted). Separation of sedimentary micron-sized particles for palaeoceanography and calcareous nannoplankton biogeochemistry. Nature protocols.
Microscopic optical potential analyses of carbon-carbon elastic scattering
NASA Technical Reports Server (NTRS)
Bidasaria, H. B.; Townsend, L. W.
Utilizing eikonal phase shifts determined from a microscopic double-folding optical potential, marked improvement in the agreement between theory and experiment, for elastic carbon-carbon scattering between 200 and 300 MeV, is obtained when only those values for the nucleon-nucleon slope parameter, appropriate for diffractive scattering, are used. The appropriateness of the perturbative eikonal expansion is discussed by comparison with recent results, obtained for the same potentials, using a more exact complex Wentzell-Kramers-Brillouin (WKB) formalism.
Fracture corridors in carbonates
NASA Astrophysics Data System (ADS)
Chatelķe, Sķbastien; Lamarche, Juliette; Gauthier, Bertrand D. M.
Among fractures, Fracture Corridors (FC) are anomalous structures made of highly persistent fracture clusters having a strong effect on multi-phase fluid flow in the subsurface. While mechanical and geological conditions for diffuse fracture systems are well constrained, FC genetic conditions remain a matter of questioning. FC can be localized in larger structures such as folds and fault zones but recent studies suggest that a large amount of fractures and FC also arise as distributed in the host rock and formed in tabular layers during burial with early rock mechanical differentiation. In addition, while the mechanical stratigraphy is of prime importance for fracture stratigraphy, it is still unknown which factor prevails on FC genesis among the local versus regional stress-state, the host rock mechanical stratigraphy or the sedimentary facies. We present a study of fractures in a 400ū300 m wide quarry (Calvisson, SE France) dug in homogeneous marly limestones of Hauterivian age. The quarry exhibits diffuse fractures as well as 16 FC. The aim of this study is to reveal the genetics factor for FC development, their global geometry and internal morphologic variations, but also to clear the impact of fracture corridors on diffuse fracture. For that, we measured >2500 fractures (strike, dip, spacing, filling, aperture, etc.) and studied microstructures in 80 thin sections. We calculated fracture density and acquired LiDAR data with >90 million points with a resolution of 4 to 15mm. Diffuse fractures are organized as two perpendicular sets, a main set NE-SW-trending and minor set NW-SE-trending. The FC have the same trend, but the NW-SE trend prevail on the NE-SW one. The LiDAR acquisition allows to visualize the 3D lateral continuity with corridors with a minimal extension of 30m. We distinguish 4 internal morphologic types in FC, depending on fracture morphology, occurrence of breccia and number of zones. The types may occur in a single FC with a lateral transition from one type to another. Fracture density study shows that diffuse fracture increase around FC. FC growth and variability was not dependent on facies variations, as they are inexistent in the quarry. The result of this study allows to interpret geomechanical behaviors and geological history of fractures and fracture corridors in carbonates.
Adsorption to carbon nanotubes
NASA Astrophysics Data System (ADS)
Kahng, Yung Ho
We have probed the adsorption property of single-wall carbon nanotube (SWNT) bundles using the temperature-programmed desorption technique. The SWNT sample cleanliness effect on the 4He adsorption was investigated. Room air contacting significantly decreased the 4He adsorption capacity. The 4He adsorption vs. pump-out temperature on SWNT samples and on charcoal was obtained. A two-state binding site model did not fit well to the SWNT data, while it fit well to the charcoal data indicating the 4He binding energy on charcoal to be 400 +/- 32 K which agreed with other group's value. Using the desorption rate isotherm analysis technique, we obtained coverage dependant 4He binding energies on SWNT bundles. Our values agreed with other group's results at near 400 K where the coverages overlapped, and our energy value increased to a much higher value at near 900 K at lower coverages beyond the lowest coverage of other group. The 4He addition temperature was changed from 273 K to lower values in the 8--40 K range for three SWNT samples and a charcoal sample. While the 4He adsorption was not sensitive on the addition temperature on charcoal, it was different on SWNT samples. Some sites were not accessible for 4He atoms at low temperatures. The 4He access to these sites increased as the gas addition temperature increased, and at 35 K and above a full 4He access to a 273 K dosed level was observed. An activated diffusion model fit to the 4He amount, vs. gas addition temperature data yielded the activation energy for diffusion to be 28 +/- 14 K and 47 +/- 6 K on two samples. One sample showed more restricted 4He access for 4He at 15 K. This sample had more impurities. Codesorption measurements were done on SWNT samples. Xe in smaller quantity (6% level) than 4He and H2, suppressed the adsorption of other gases to the background level. H2 suppressed 4 He to the background level, when added in equal amount at 273 K. However when 4He was added at 273 K and H2 was added later at 19 K, H2 did not suppress the 4He adsorption. Equal mixture doses of 4He and 3He at 273 K yielded 8.4 times more 4He binding than 3He. This strong isotope selectivity agreed with the predicted quantum sieving effect.
NASA Astrophysics Data System (ADS)
Nixon, C. A.; Jennings, D. E.; Teanby, N. A.; Vinatier, S.; BÉ Zard, B.; Coustenis, A.; Irwin, P. G.; Flasar, F. M.; Cassini Cirs Team
As recently as a year ago, a consensus was emerging that carbon-13 in Titan's methane was enriched by some ~10% over the terrestrial value (12C/13C = ~77-82 on Titan versus 89 on Earth, Niemann et al 2005, Nixon et al 2008). At the same time, several measurements of 12C/13C in ethane, the main product of methane photolysis, appeared to show no enrichment (Nixon et al 2008, Jennings et al 2009). This led to the suggestion that a steady state equilibrium was being reached, with a Kinetic Isotope Effect (KIE) in a key reaction (C2H + CH4 ? C2H2 + CH3) responsible for the slight enrichment in the atmospheric reservoir relative to both the incoming flux of methane and outgoing flux of ethane (Jennings et al 2009). This paradigm was overturned earlier this year when the Huygens GCMS team revised their measurement of 12CH4/13CH4 upwards to agree with the terrestrial value (Niemann et al, in preparation), eliminating any need for the KIE fractionation. However, this presents a new problem in the sense that the KIE effect is probably real - it is confirmed for the CH3D and 12CH4 reactions with ethynyl (Opansky and Leone 1996), so almost certainly for 13CH4-12CH4 pair as well - and so some fractionation of methane should be occurring. This is true regardless as to whether the atmospheric methane is being replenished or not - differing only in degree - provided the ethynyl abstraction reaction is the dominant path for methane loss as predicted by current models (Lavvas et al. 2008). In this forum we will present updated measurements by the CIRS team of the 12CH4/13CH4 derived from recent high signal-to-noise Titan observations, and discuss the degree of agreement with both the earlier published ratios, and the newer revised GCMS results. We will also discuss the implications for Titan's methane evolution over geologic time including clues from the D/H ratio. We conclude by highlighting the currently open questions and avenues for future work. Jennings, D.E. et al., J. Chem. Phys., 113(42), 11101-11106, 2009. Lavvas, P.P. et al., Plan. Space Science, 56, 27-66, 2008. Niemann, H.B. et al., Nature, 438, 779-784, 2005. Nixon, C.A. et al., Icarus, 195, 778-791, 2008. Opansky, B.J and S.R. Leone, J. Phys. Chem., 100, 4888-4892, 1996.
Enhancement of Carbon Sequestration in US Soils
NSDL National Science Digital Library
WILFRED M. POST, R. CESAR IZAURRALDE, JULIE D. JASTROW, BRUCE A. McCARL, JAMES E. AMONETTE, VANESSA L. BAILEY, PHILIP M. JARDINE, TRISTRAM O. WEST, and JIZHONG ZHOU (; )
This peer-reviewed article from Bioscience journal is about the importance of improving land management to increase carbon sequestration in US soils. Improved practices in agriculture, forestry, and land management could be used to increase soil carbon and thereby significantly reduce the concentration of atmospheric carbon dioxide. Understanding biological and edaphic processes that increase and retain soil carbon can lead to specific manipulations that enhance soil carbon sequestration. These manipulations, however, will only be suitable for adoption if they are technically feasible over large areas, economically competitive with alternative measures to offset greenhouse gas emissions, and environmentally beneficial. Here we present the elements of an integrated evaluation of soil carbon sequestration methods.
Structure of nanoporous carbon materials for supercapacitors
NASA Astrophysics Data System (ADS)
Volperts, A.; Mironova-Ulmane, N.; Sildos, I.; Vervikishko, D.; Shkolnikov, E.; Dobele, G.
Activated carbons with highly developed porous structure and nanosized pores (8 - 11 ┼) were prepared from alder wood using thermochemical activation method with sodium hydroxide. Properties of the obtained activated carbons were examined by benzene and nitrogen sorption, X-Ray diffraction and Raman spectroscopy. Tests of activated carbons as electrodes in supercapacitors were performed as well. It was found that specific surface area of above mentioned activated carbons was 1800 m2/g (Dubinin - Radushkevich). Raman spectroscopy demonstrated the presence of ordered and disordered structures of graphite origin. The performance of activated carbons as electrodes in supercapacitors have shown superior results in comparison with electrodes made with commercial carbon tissues.
Superhard Monoclinic Polymorph of Carbon
Li, Quan; Ma, Yanming; Oganov, Artem R.; Wang, Hongbo; Wang, Hui; Xu, Ying; Cui, Tian; Mao, Ho-Kwang; Zou, Guangtian; Jilin; SBU; CIW
We report a novel phase of carbon possessing a monoclinic C2/m structure (8 atoms/cell) identified using an ab initio evolutionary structural search. This polymorph, which we call M-carbon, is related to the (2x1) reconstruction of the (111) surface of diamond and can also be viewed as a distorted (through sliding and buckling of the sheets) form of graphite. It is stable over cold-compressed graphite above 13.4 GPa. The simulated x-ray diffraction pattern and near K-edge spectroscopy are in satisfactory agreement with the experimental data [W.L. Mao et al., Science 302, 425 (2003)] on overcompressed graphite. The hardness and bulk modulus of this new carbon polymorph are calculated to be 83.1 and 431.2 GPa, respectively, which are comparable to those of diamond.
Precursors for Carbon Nitride Synthesis
Prashantha, M.; Gopal, E. S. R.; Ramesh, K. [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)
Nano structured carbon nitride films were prepared by pyrolysis assisted chemical vapour deposition. Pyrrole (C{sub 4}H{sub 5}N), Pyrrolidine (C{sub 4}H{sub 9}N), Azabenzimidazole (C{sub 6}H{sub 5}N{sub 3}) and Triazine (C{sub 6}H{sub 15}N{sub 3}) were used as precursors. The vibrational modes observed for C-N and C = N from FTIR spectra confirms the bonding of nitrogen with carbon. XPS core level spectra of C 1s and N 1s also show the formation of bonding between carbon and nitrogen atoms. The nitrogen content in the prepared samples was found to be around 25 atomic %.
Carbon Nanosheets: Synthesis and Application.
Fan, Huailin; Shen, Wenzhong
Carbon nanosheets (CNSs) with tunable sizes, morphologies, and pore structures have been synthesized through several chemical routes. Graphitized CNSs have been synthesized through exfoliation, chemical vapor deposition, or high-temperature carbonization. Porous CNSs have been synthesized by using various methods, including pyrolysis, self-assembly, or a solvothermal method in connection with carbonization. These CNSs have successfully been used as detectors for metal ions, as cathodes for field electron emissions, as electrodes for supercapacitors and fuel cells, and as supports for photocatalytic and catalytic oxygen reduction. Therefore, the synthesis and application of CNSs are receiving increasing levels of interest, particularly as application benefits, in the context of future energy/chemical industry, are becoming recognized. This review provides a summary of the most recent and important progress in the production of CNSs and highlights their application in environmental and energy-related fields. PMID:26036331
EDITORIAL: Focus on Carbon Nanotubes
NASA Astrophysics Data System (ADS)
The study of carbon nanotubes, since their discovery by Iijima in 1991, has become a full research field with significant contributions from all areas of research in solid-state and molecular physics and also from chemistry. This Focus Issue in New Journal of Physics reflects this active research, and presents articles detailing significant advances in the production of carbon nanotubes, the study of their mechanical and vibrational properties, electronic properties and optical transitions, and electrical and transport properties. Fundamental research, both theoretical and experimental, represents part of this progress. The potential applications of nanotubes will rely on the progress made in understanding their fundamental physics and chemistry, as presented here. We believe this Focus Issue will be an excellent guide for both beginners and experts in the research field of carbon nanotubes. It has been a great pleasure to edit the many excellent contributions from Europe, Japan, and the US, as well from a number of other countries, and to witness the remarkable effort put into the manuscripts by the contributors. We thank all the authors and referees involved in the process. In particular, we would like to express our gratitude to Alexander Bradshaw, who invited us put together this Focus Issue, and to Tim Smith and the New Journal of Physics staff for their extremely efficient handling of the manuscripts. Focus on Carbon Nanotubes Contents <;A article="1367-2630/5/1/117">Transport theory of carbon nanotube Y junctions R Egger, B Trauzettel, S Chen and F Siano The tubular conical helix of graphitic boron nitride F F Xu, Y Bando and D Golberg Formation pathways for single-wall carbon nanotube multiterminal junctions Inna Ponomareva, Leonid A Chernozatonskii, Antonis N Andriotis and Madhu Menon Synthesis and manipulation of carbon nanotubes J W Seo, E Couteau, P Umek, K Hernadi, P Marcoux, B Lukic, Cs Mik¾, M Milas, R Gaßl and L Forr¾ Transitional behaviour in the transformation from active end planes to stable loops caused by annealing M Endo, B J Lee, Y A Kim, Y J Kim, H Muramatsu, T Yanagisawa, T Hayashi, M Terrones and M S Dresselhaus Energetics and electronic structure of C70-peapods and one-dimensional chains of C70 Susumu Okada, Minoru Otani and Atsushi Oshiyama Theoretical characterization of several models of nanoporous carbon F Valencia, A H Romero, E Hernßndez, M Terrones and H Terrones First-principles molecular dynamics study of the stretching frequencies of hydrogen molecules in carbon nanotubes Gabriel Canto, Pablo Ordej¾n, Cheng Hansong, Alan C Cooper and Guido P Pez The geometry and the radial breathing mode of carbon nanotubes: beyond the ideal behaviour Jeno K³rti, Viktor Z¾lyomi, Miklos Kertesz and Sun Guangyu Curved nanostructured materials Humberto Terrones and Mauricio Terrones A one-dimensional Ising model for C70 molecular ordering in C70-peapods Yutaka Maniwa, Hiromichi Kataura, Kazuyuki Matsuda and Yutaka Okabe Nanoengineering of carbon nanotubes for nanotools Yoshikazu Nakayama and Seiji Akita Narrow diameter double-wall carbon nanotubes: synthesis, electron microscopy and inelastic light scattering R R Bacsa, E Flahaut, Ch Laurent, A Peigney, S Aloni, P Puech and W S Bacsa Sensitivity of sin
Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide.
Loring, John S; Chen, Jeffrey; Bķnķzeth, Pascale; Qafoku, Odeta; Ilton, Eugene S; Washton, Nancy M; Thompson, Christopher J; Martin, Paul F; McGrail, B Peter; Rosso, Kevin M; Felmy, Andrew R; Schaef, Herbert T
Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 ░C and 90 bar using an in situ IR titration capability, and postreaction samples were examined by ex situ techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), focused ion beam transmission electron microscopy (FIB-TEM), thermal gravimetric analysis mass spectrometry (TGA-MS), and magic angle spinning nuclear magnetic resonance (MAS NMR). Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 ?mol/m(2). Above this concentration and up to 76 ?mol/m(2), monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 ?mol/m(2), crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 ┼. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth. PMID:26079871
Global Carbon Reservoir Oxidative Ratios
NASA Astrophysics Data System (ADS)
Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.
Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.
Increased topsoil carbon stock across China's forests.
Yang, Yuanhe; Li, Pin; Ding, Jinzhi; Zhao, Xia; Ma, Wenhong; Ji, Chengjun; Fang, Jingyun
Biomass carbon accumulation in forest ecosystems is a widespread phenomenon at both regional and global scales. However, as coupled carbon-climate models predicted, a positive feedback could be triggered if accelerated soil carbon decomposition offsets enhanced vegetation growth under a warming climate. It is thus crucial to reveal whether and how soil carbon stock in forest ecosystems has changed over recent decades. However, large-scale changes in soil carbon stock across forest ecosystems have not yet been carefully examined at both regional and global scales, which have been widely perceived as a big bottleneck in untangling carbon-climate feedback. Using newly developed database and sophisticated data mining approach, here we evaluated temporal changes in topsoil carbon stock across major forest ecosystem in China and analysed potential drivers in soil carbon dynamics over broad geographical scale. Our results indicated that topsoil carbon stock increased significantly within all of five major forest types during the period of 1980s-2000s, with an overall rate of 20.0 g C m(-2) yr(-1) (95% confidence interval, 14.1-25.5). The magnitude of soil carbon accumulation across coniferous forests and coniferous/broadleaved mixed forests exhibited meaningful increases with both mean annual temperature and precipitation. Moreover, soil carbon dynamics across these forest ecosystems were positively associated with clay content, with a larger amount of SOC accumulation occurring in fine-textured soils. In contrast, changes in soil carbon stock across broadleaved forests were insensitive to either climatic or edaphic variables. Overall, these results suggest that soil carbon accumulation does not counteract vegetation carbon sequestration across China's forest ecosystems. The combination of soil carbon accumulation and vegetation carbon sequestration triggers a negative feedback to climate warming, rather than a positive feedback predicted by coupled carbon-climate models. PMID:24453073