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Some comments on the views of Niaz, Rodriguez and Brito on Mendeleev's periodic system
Scientific Electronic Library Online (English)
Eric, Scerri.
Full Text Available Many articles have been written about the value of incorporating an understanding of history and philosophy of science into science education and this has included the teaching of chemistry. Given the immense role that the periodic table plays in chemistry it is important to be clear about a histori [...] cal and philosophical perspective on the periodic table and its possible ramifications for the way in which chemistry is presented. The article presents a critique of a paper by Niaz, Rodriguez and Brito who have addressed the relevance of historical and philosophical aspects of the periodic table in an article in which they have claimed that Mendeleev's periodic table should be regarded as a theory. In addition they have claimed that Mendeleev was a supporter of the atomic theory and have addressed some general philosophical questions concerning inductivism and the role of prediction and accommodation in the acceptance of scientific discoveries.
Interaction properties of ytterbium with elements of Mendeleev periodic table
International Nuclear Information System (INIS)
This article presents the new data on ytterbium interaction with elements of Mendeleev periodic table. The state diagrams of ytterbium with magnesium, calcium, strontium, and barium are constructed. The state diagrams of ytterbium with Cu, Ag, Au, Zn, Cd, Hg, B,Al, Ga, In, Tl are considered.
From the Mendeleev periodic table to particle physics and back to the periodic table
Energy Technology Data Exchange (ETDEWEB)
Kibler, Maurice R. [Universite de Lyon, Institut de Physique Nucleaire, Universite Lyon 1 and CNRS/IN2P3, 43 Bd du 11 Novembre 1918, F-69622 Villeurbanne Cedex (France)
We briefly describe in this paper the passage from Mendeleev's chemistry (1869) to atomic physics (in the 1900's), nuclear physics (in the 1932's) and particle physics (from 1953 to 2006). We show how the consideration of symmetries, largely used in physics since the end of the 1920's, gave rise to a new format of the periodic table in the 1970's. More specifically, this paper is concerned with the application of the group SO(4,2)xSU(2) to the periodic table of chemical elements. It is shown how the Madelung rule of the atomic shell model can be used for setting up a periodic table that can be further rationalized via the group SO(4,2)xSU(2) and some of its subgroups. Qualitative results are obtained from this nonstandard table. (author)
The comparison of element composition of Venus, Earth, Mars, and chondrites in the light of the Mendeleev Periodic Law
International Nuclear Information System (INIS)
The share of free neutral atoms, N0, for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrites and igneous rocks of the Earth on N0 was obtained. The Mendeleev Periodic Law was used to obtain the proof of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. To this end the concentration ratios of element-analogous with different N0 in the matters of Venus, Earth, Mars, and chondrites were compared. The data obtained are sufficient demonstration of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. With the account of the above said, it was shown that Shergotty and Tunguska meteorites by their relative elemental composition are close to Mars and asteroids, respectively. (author)
The slow penetration of the Mendeleev Table in the French school curricula
International Nuclear Information System (INIS)
The great influence of the Berthelot's ideas about the non existence of atoms froze the teaching of chemistry in France for quite a long time. It is only after the Second World War that the study of the atom structure appeared in school curricula. The Mendeleev periodic system that sets the relationship between chemical properties and atom structure entered the curriculum even later in 1978. The article shows that the authors of most school manuals had anticipated the change, for in 1966 all the chemistry manuals of the 6. form had a chapter dedicated to the Mendeleev table while the issue was not yet on the syllabus. (A.C.)
Geometrochemistry vs Soft Computing of Mendeleev's Brain.
Czech Academy of Sciences Publication Activity Database
Gottvald, AleÜ
Brno : Brno University of Technology , 2010, s. 558-564. ISBN 978-80-214-4120-0. [Mendel 2010 - International Conference on Soft Computing /16./. Brno (CZ), 23.06.2010-25.06.2010] Institutional research plan: CEZ:AV0Z20650511 Keywords : projective geometry * Law of Mass Action * Mendeleev periodic table * brain information processing * artificial neural networks * cross-ratio * incidence structures Subject RIV: BD - Theory of Information
Nationalism and the Process of Reception and Appropriation of the Periodic System in Europe and the Czech Lands.
Czech Academy of Sciences Publication Activity Database
Ŗtrbß?ovß, So?a
Oxford : Oxford University Press, 2015 - (Kaji, M.; Kragh, H.; Pallo, G.), s. 121-149 ISBN 978-0-19-020007-7 R&D Projects: GA AV ?R IAAX00630801 Institutional support: RVO:68378114 Keywords : D. I. Mendeleev * B. Brauner * history of the periodic system of elements Subject RIV: AB - History
Reconstruction of late Quaternary sedimentary environments at the southern Mendeleev Ridge (Arctic Ocean)
Bazhenova, Evgenia
The late Pleistocene history of the Arctic comprised cyclical changes in the extension of land-based ice sheets and sea-ice cover that affected sedimentary environments in the Arctic Ocean. This PhD thesis focuses on sediment records from the Mendeleev Ridge spanning the last 200 ka. Over this time period, variable sedimentation patterns were described and possible implications for reconstruction of glacial/interglacial paleoenvironments were provided. One of the main goals of this study was ...
Directory of Open Access Journals (Sweden)
Raos, N.
Full Text Available The Croatian (Yugoslav Academy of Sciences and Arts was the first academy to elect D. I. Mendeleev as its honorary member (1882, whereas the periodic table of the elements has been taught regularly at the Zagreb University since 1888. The early interest of Croatian chemists in the periodic table should be attributed primarily to their pan-Slavic attitude, particularly as proof that Slavic people were able to produce "their own Newtons" (M. V. Lomonosov and D. I. Mendeleev. Such enthusiastic views, however, did not help in analyzing the contribution of Mendeleev and other scientists to the discovery and development of the periodic table of the elements.
Atlantic water circulation over the Mendeleev Ridge and Chukchi Borderland from thermohaline intrusions and water mass properties
Woodgate, Rebecca A.; Aagaard, Knut; Swift, James H.; Smethie, William M.; Falkner, Kelly K.
Hydrographic and tracer data from 2002 illustrate Atlantic water pathways and variability in the Mendeleev Ridge and Chukchi Borderland (CBLMR) region of the Arctic Ocean. Thermohaline double diffusive intrusions (zigzags) dominate both the Fram Strait (FSBW) and Barents Sea Branch Waters (BSBW) in the region. We show that details of the zigzags' temperature-salinity structure partially describe the water masses forming the intrusions. Furthermore, as confirmed by chemical tracers, the zigzags' peaks contain the least altered water, allowing assessment of the temporal history of the Atlantic waters. Whilst the FSBW shows the 1990s warming and then a slight cooling, the BSBW has continuously cooled and freshened over a similar time period. The newest boundary current waters are found west of the Mendeleev Ridge in 2002. Additionally, we show the zigzag structures can fingerprint various water masses, including the boundary current. Using this, tracer data and the advection of the 1990s warming, we conclude the strongly topographically steered boundary current, order 50 km wide and found between the 1500 m and 2500 m isobaths, crosses the Mendeleev Ridge north of 80░N, loops south around the Chukchi Abyssal Plain and north around the Chukchi Rise, with the 1990s warming having reached the northern (but not the southern) Northwind Ridge by 2002. Pacific waters influence the Atlantic layers near the shelf and over the Chukchi Rise. The Northwind Abyssal Plain is comparatively stagnant, being ventilated only slowly from the north. There is no evidence of significant boundary current flow through the Chukchi Gap.
Late Quaternary Sedimentary Records of Core MA01 in the Mendeleev Ridge, the Western Arctic Ocean: Preliminary Results
Park, K.; Kim, S.; Khim, B. K.; Wang, R.; Mei, J.; Xiao, W.; Polyak, L. V.
Late Quaternary deep sea sediments in the Arctic Ocean are characterized by brown layers intercalated with yellowish to olive gray layers. It has been known that the brown and gray layers were deposited during interglacial (or interstadial) and glacial (or stadial) periods, respectively. A 5.5-m long gravity core MA01 was obtained from the Mendeleev Ridge in the western Arctic Ocean by R/V Xue Long during scientific cruise CHINARE-V. Age (~1.0 Ma) of core MA01 was tentatively decided by correlation of sediment color cycles, XRF Mn and Ca cycles, and geomagnetic inclinations with core HLY0503-8JPC (Adler et al., 2009) and core HLY0503-06JPC(Cronin et al., 2013) that were also collected from the Mendeleev Ridge area. A total of 23 brown layers are characterized by low L* and b*, high Mn concentration, and abundant foraminifera. In contrast, gray layers are characterized by high L* and b*, low Mn concentration, and few foraminiferal tests. Foraminifera abundance peaks are not well correlated to CaCO3 peaks which are accompanied with the coarse-grained (>63 ?m) fractions (i.e., IRD) both in brown and gray layers. A strong positive correlation coefficient (r2=0.89) between TOC content and C/N ratio indicates that the major source of organic matter is terrestrial. The good correlations of CaCO3 content to TOC (r2=0.56) and C/N ratio (r2=0.69) imply that IRDs contain detrital CaCO3 fraction which mainly originated from the Canadian Arctic Archipelago. In addition, high kaolinite/chlorite (K/C) ratios mostly correspond to CaCO3 peaks, also suggesting that the fine-grained particles in the Mendeleev Ridge were transported from the northern coasts of the Alaska and Canada. Thus, the Beaufort Gyre, the predominant surface current in the western Arctic Ocean, has played an important role in the sediment delivery to the Mendeleev Ridge. It is worthy of note that TOC and CaCO3 peaks are obviously distinct in the upper part of core MA01, whereas these peaks are reduced in the lower part of the core. More study on these contrasting features is in progress.
Ice-cover History and Paleoceanographic Change of the Western Arctic Ocean (Mendeleev Ridge) using Be isotopes
Kim, K. J.; Jull, A. J. T.; Nam, S. I.
A new investigation of paleoclimate and environmental changes using beryllium isotopes in sediment from the Mendeleev Ridge of the western Arctic Ocean was accomplished using a 39 cm-long box core record. The age of core PS72/396-3 appears to date back to MIS 5.d based on the stratigraphy of beryllium isotopes and paleomagnetic data and other isotopic data of this study, AMS 14C ages and oxygen and carbon isotopes of planktonic foraminifera N. pachyderma sin. Both authigenic 10Be and 9Be records show that there are three major cold periods during MIS 5.d and reveals a much longer warm period after the second cold period based on 9Be record. The 10Be stratigraphy also reveals a paleomagetic excursion at 45 kyr which is comparable to other records. At depths from 22 to 25 cm, the lowest 10Be signal may be due to the highest paleomagnetic intensity, which is indicated as an age of 75 kyr from other records. However, a reduction in cosmogenic 10Be could be due to ice cover, and is correlated with ?18O evidence fo a cold period. Interestingly, 9Be data show that constant input of 9Be to the Mendeleev Ridge is observed for this time period. During this time period, TOC (%) values also show a similar pattern. The record of authigenic 9Be is inversely correlated to that of Ca and proportional to opal production. These observations confirm that 9Be can also be a good proxy as a climatic tracer. This study may be a useful approach for understanding Arctic climate change.
Paleomagnetic Studies of Marine Sediments for Evaluation of Sedimentation Rates on the Mendeleev Ridge, Arctic Ocean
Elkina, D.
Nowadays the Arctic Ocean is an area of higher scientific interest. Investigation of composition, genesis, sources and source areas of marine sediments is necessary for a gain of geological knowledge and geo-engineering development of the region. One should note that the dating issue in the Arctic Ocean is a challenge by itself. However, magnetostratigraphy can offer a powerful stratigraphic tool applying to marine sediments here. The 6-meters length core was retrieved from the Mendeleev Ridge in 2012 and subjected to paleomagnetic studies. The examined core was revealed to dominate by normal polarity up to 123 cm below seafloor (cmbsf) and assigned there to the Brunhes polarity chron of the geomagnetic field (0.78 Ma). Then prevalence of reverse polarity persists up to 394-397 cmbsf, assigned to Matuyama age, and short positive intervals are believed to be subchrons of normal polarity. Change from reverse to normal polarity at 394-397 cmbsf is considered as the Matuyama - Gauss (2.58 Ma) boundary and is traced up to 530-531 cmbsf including one short reversal. After this depth a drop back to reverse polarity is ascribed to the beginning of the Gilbert polarity chron (3.58 Ma). The resultant magnetostratigraphy is presented on Figure 1. The stepwise alternating field demagnetization and demagnetization by heating were performed to remove viscous overprints and then to define component magnetization directions. Spikes of natural remanent magnetization intensity and magnetic susceptibility are discovered near almost all assigned chron boundaries, and it may act as an independent factor for determination of polarity boundaries. Anisotropy of magnetic susceptibility is also considered in order to find out additional peculiarities of the sedimentation. The relative abundance of shallow inclinations at least implies the existence of secondary processes, which may have altered the paleomagnetic record. The mean sedimentation rates on the Mendeleev Ridge do not exceed 1.58 mm kyr-1 for 3.58 Ma and therefore represent the sedimentation rates as low for the whole Quaternary period and also for the part of the Pliocene epoch.
Transgressive Legacies of Memory : The Concept of Technķ in Primo Levi's 'Periodic Table'
Botez, Catalina
This chapter is looking at Italian writer Primo LeviÆs most original work Il sistema periodico (1975), translated in English as The Periodic Table (1995), which engages in a fascinating manner with the overlapping spheres of (auto)biography, memoir, poetical myth and fiction. This compelling literary hybrid mingles landmarks of personal pre- and post-WWII experience with significant fictitious tales, mapped around elements of MendeleevÆs periodic table.The concept that binds all twenty on...
Acquisition of long-offset seismic refraction data in the Chukchi Borderlands and Mendeleev Ridge
Vermeesch, P. M.; van Avendonk, H. J.; Lawver, L. A.; Hornbach, M. J.; Wiederspahn, M.; Saustrup, S.; Mironov, A.; Stevenoski, S.; Asher, C.; Bain, K.; McDonald, M.; Young, R.
The deep structure of the Chukchi Borderlands and Mendeleev Ridge is important for our understanding of the tectonic history of the western Arctic Ocean. Our constraints on the crustal structure of this region are sparse because the nearly continuous ice cover makes the acquisition of marine seismic refraction data difficult. In July and August of 2006 we gathered a unique seismic refraction data set on the Chukchi Borderlands and Mendeleev Ridge utilizing USCGC Healy and two helicopters. In order to obtain seismic refractions from an air- gun source over long offsets, we placed seismic instruments on the sea ice by helicopter. Each of the stations was equipped with a geophone, hydrophone, GPS unit and radio. The instruments were left on ice for several days, making occasional radio contact with either the ship or the helicopter to give us their latest location. We deployed an array of 12 instruments across the Northwind Escarpment into the Canada Basin, 13 instruments on an east-west transect across Chukchi Cap, and 14 seismometers on a refraction line parallel to the crest of Mendeleev Ridge. One instrument on the Chukchi Cap was lost at sea, but the other instruments were successfully retrieved with their refraction data. The instrument arrays recorded air-gun shots over distances up to 150 km. We will use the first-arrival time data to estimate the two-dimensional seismic velocity structure along the three profiles that were gathered on this cruise.
Recent Mapping and Sampling on Chukchi Borderland and the Alpha/Mendeleev Ridge Complex
Mayer, L. A.; Brumley, K.; Andronikov, A.; Chayes, D. N.; Armstrong, A. A.; Calder, B.; Hall, J. K.; Clyde, W. C.; Bothner, W. A.; Gardner, J. V.
Since 2003, four cruises on the icebreaker USCG HEALY have collected high-resolution multibeam sonar mapping data in the Amerasia Basin in support of a potential submission by the U.S. for an extended continental shelf as defined under the United Nations Convention on Law of the Sea Article 76. The latest of these cruises (HEALY0805), completed in early Sept.of 2008, extended this mapping to the southern portions of the Alpha/Mendeleev Ridge complex, and supplemented the mapping with seven dredge stations, providing rare, direct sampling of both regions. While sparse in comparison to complete-coverage multibeam sonar surveys (due to the difficulties associated with operating in ice-covered waters), the new multibeam sonar data still provide an unprecedented new view of the tectonic, sedimentary, glacial and fluid- flow related processes in the Arctic Ocean. The Chukchi Borderland is characterized by shallow plateaus that often show evidence of interaction with icebergs and glaciers (scours and grooves) at depths as great as 900 m, as well as the presence of numerous gas/fluid expulsion features (pockmarks and acoustic wipe-out zones). The topographic highs associated with the Borderland are often bounded by very steep scarps including the eastern edge of Northwind Ridge (the Northwind Escarpment) which is a 600 km long NNE trending feature with an average slope of 10-15 degrees. Similar steep-sided ridges, separated by deep linear valleys also appear in mapped areas of the Alpha/Mendeleev Ridge complex. Some of these features have slopes as great at 60 degrees and thus are excellent targets for dredging. Our dredging of these slopes has returned a wide array of volcanic and sedimentary rock types, many of which appear to be representative of outcrops (rather than ice rafted material). A preliminary shipboard examination of these samples (they were just collected this morning - 3 September 2008 - a few days before the abstract is due) shows them to include mudstone, sandstone, shale, breccia, along with volcanic and metamorphic rocks lending support to the earlier evidence for the continental origin of the Chukchi Borderland. Dredges from the topographic highs of the southern part of Alpha/Mendeleev Ridge complex returned indurated sediment with defined sedimentary structures that appear to be non-marine in origin; further descriptions of the nature of these rocks and speculation about their implications for the origin of the features from which they were dredged will require more detailed laboratory analyses which will be carried out in the coming months.
Periodic Orbits and Escapes in Dynamical Systems
Contopoulos, George; Harsoula, Mirella; Lukes-gerakopoulos, Georgios
We study the periodic orbits and the escapes in two different dynamical systems, namely (1) a classical system of two coupled oscillators, and (2) the Manko-Novikov metric (1992) which is a perturbation of the Kerr metric (a general relativistic system). We find their simple periodic orbits, their characteristics and their stability. Then we find their ordered and chaotic domains. As the energy goes beyond the escape energy, most chaotic orbits escape. In the first case we c...
Directory of Open Access Journals (Sweden)
Full Text Available The basic aim of ancient education was instilling into the minds, of peoples aspirit of being pious and religious for glory of God and good of man. The pursuit ofknowledge was a pursuit of religious values. The student had to observe strictregulations. Instruction was important, but was even more significant than teaching wasdiscipline ¢ discipline inculcated through strict obedience to laws and regulations ofstudent life, discipline that was rooted in morality and religion A student was required togive up lust, anger, greed, vanity, conceit and over joy. Education was free. It was freebecause no student was required to pay any fees. It was free also because no outsideagency could interfere in the matters of education. There was perfect autonomy. Noexternal authority no external beneficiary, no politics was permitted to enter the schoolor college system. A student had to pay nothing in return for education he received in aGurukul. The inculcation of civic virtues and social values was an equally importantobjective of education in India. The Brahmachari after his education in the Gurukulaswent back to the society to serve the rich and the poor, to relieve the diseased and thedistressed.
Design of periodic beam-transport systems
Energy Technology Data Exchange (ETDEWEB)
Farrell, J.A.
Periodic beam-transport systems have several advantages including insensitivity to errors, minimum magnet apertures, and use of standardized components. A simple procedure is given for the design of modules, with and without bending magnets, that have the same matched beam properties. These modules can be combined in certain ways to produce systems that are achromatic and require a minimum number of matching elements.
Localized states in periodically forced systems.
Gandhi, Punit; Knobloch, Edgar; Beaume, Cķdric
The theory of stationary spatially localized patterns in dissipative systems driven by time-independent forcing is well developed. With time-periodic forcing, related but time-dependent structures may result. These may consist of breathing localized patterns, or states that grow for part of the cycle via nucleation of new wavelengths of the pattern followed by wavelength annihilation during the remainder of the cycle. These two competing processes lead to a complex phase diagram whose structure is a consequence of a series of resonances between the nucleation time and the forcing period. The resulting diagram is computed for the periodically forced quadratic-cubic Swift-Hohenberg equation, and its details are interpreted in terms of the properties of the depinning transition for the fronts bounding the localized state on either side. The results are expected to shed light on localized states in a large variety of periodically driven systems. PMID:25659000
Periodic Orbits and Escapes in Dynamical Systems
Contopoulos, George; Lukes-Gerakopoulos, Georgios
We study the periodic orbits and the escapes in two different dynamical systems, namely (1) a classical system of two coupled oscillators, and (2) the Manko-Novikov metric (1992) which is a perturbation of the Kerr metric (a general relativistic system). We find their simple periodic orbits, their characteristics and their stability. Then we find their ordered and chaotic domains. As the energy goes beyond the escape energy, most chaotic orbits escape. In the first case we consider escapes to infinity, while in the second case we emphasize escapes to the central "bumpy" black hole. When the energy reaches its escape value a particular family of periodic orbits reaches an infinite period and then the family disappears (the orbit escapes). As this family approaches termination it undergoes an infinity of equal period and double period bifurcations at transitions from stability to instability and vice versa. The bifurcating families continue to exist beyond the escape energy. We study the forms of the phase spac...
Multichannel long period seismic data acquisition system
International Nuclear Information System (INIS)
This paper discusses the specifications and performance of an eight channel long period seismic digital data acquisition system, which is developed and installed at Seismic Array Station, Gauribidanur, Karnataka State. The paper describes how these data in an unedited form are recorded on a single track of magnetic tape inter-mittantly, which has resulted in recording of 50 days data on a single tapespool. A time indexing technique which enables quick access to any desired portion of a recorded tape is also discussed. Typical examples of long period seismic event signals recorded by this system are also illustrated. Various advantages, the system provides over the analog multichannel instrumentation tape recording system, operating at Seismic Array Station for th e last two decades, are also discussed. (author). 7 figs
First Recovery of Submarine Basalts from the Chukchi Borderland and Alpha / Mendeleev Ridge, Arctic Ocean
Andronikov, A.; Mukasa, S.; Mayer, L. A.; Brumley, K.
In addition to multibeam bathymetric mapping of the Amerasia Basin in the high Arctic Ocean, the August- September 2008 cruise of USCGC Icebreaker HEALY (HLY0805) conducted a total of seven dredging profiles along the southern sectors of the Alpha/Mendeleev Ridge and in the northernmost region of Northwind Ridge of Chukchi Borderland. Five of the seven dredges were recovered on relatively gentle slopes (30-40░) and yielded mostly mud with a small number of fragments of sedimentary rocks and ice rafted debris (IRD), which indicates either rapid sedimentation rates on the bathymetrically high features sampled or lack of recently active volcanism on these features. Two dredges taken from steep escarpments with slopes (> 55░) at >3.5 km depth recovered some of the first known submarine basaltic samples from the Arctic Ocean floor away from the Gakkel Ridge. Ragged, freshly exposed edges indicate that these samples were broken from outcrop rather than being IRD. In some cases (e.g., a rise on the ocean floor between the Alpha/Mendeleev Ridge and Northwind Ridge) the samples have well-preserved pillow-basalt structures with fresh glassy rims up to 4 cm thick. Inward from the rims, the rocks are dark-grey lavas, some with visible plagioclase laths and rare phenocrysts up to 0.5 mm in length, some with visible signs of alteration such as local occurrence of chlorite. Surfaces that were exposed to water can be covered with a thin black film of Mn oxides. Occurrence of this volcanism away from any obvious spreading centers compels us to hypothesize that forthcoming geochemical analyses are likely to identify these rocks as the first Arctic Ocean floor samples to exhibit ocean island basalt compositions. The dredge taken from the northern slope of Northwind Ridge, along slopes as steep as > 45░, recovered a variety of rock types including sedimentary and basaltic rocks. Some of the basalts have columnar jointing (the size of the columns is only up to 5-6 cm across, suggesting fairly thin lava flows). These samples have a strongly altered glassy matrix with abundant plagioclase phenocrysts (up to 3 mm in length). Thin chilled basaltic crust on the lava surfaces displays pahoehoe structures, suggesting subaerial eruptions. Presence of subaerial basalts in this area supports the notion that the Chukchi Borderland has a continental origin. It is possible that further mapping using multibeam bathymetric methods and geochemical studies will show the high Arctic to possess a large igneous province built on both continental and oceanic crust.
The long period seismic system of Gauribidanur
International Nuclear Information System (INIS)
This report describes the seismic long-period data acquisition system at Gauribidanur. The field electronics was designed to achieve a configuration of improved stability and dynamic range in the pass band of 0.025-0.1 hz. Some typical records obtained by the system are shown. Surface wave magnitudes estimated at the Gauribidanur Seismic Array are found to be in general agreement with those of international estimates. (author)
Periodic Solutions for Highly Nonlinear Oscillation Systems
DEFF Research Database (Denmark)
Ghadimi, M; Barari, Amin
In this paper, Frequency-Amplitude Formulation is used to analyze the periodic behavior of tapered beam as well as two complex nonlinear systems. Many engineering structures, such as offshore foundations, oil platform supports, tower structures and moving arms, are modeled as tapered beams. The results obtained are compared with Variational Iteration Method (VIM) and other analytical methods as well as time marching solution. The results given show the effectiveness and accuracy of the proposed techniques.
Periodic inspections of the primary system
International Nuclear Information System (INIS)
An impression is given of the inspection techniques, preparations and background for periodic examinations of the primary system of the Dodewaard Nuclear Reactor over the past 10 years. Unfortunately reliable integral inspection techniques to enable 'listening-in' to developing faults, are not yet available. Until they are, inspections will continue to be executed from a distance using different continuous methods, often under water and with a shortage of space and in the presence of ionising radiations. (C.F.)
AN┴LISE DA ABORDAGEM HISTėRICA PARA A TABELA PERIėDICA EM LIVROS DE QU═MICA GERAL PARA O ENSINO SUPERIOR USADOS NO BRASIL NO S╔CULO XX / ANALYSIS OF HISTORICAL APPROACHES TO THE PERIODIC TABLE IN GENERAL CHEMISTRY COLLEGE TEXTBOOKS USED IN BRAZIL IN THE TWENTIETH CENTURY
Scientific Electronic Library Online (English)
Helena S. A., Leite; Paulo A., Porto.
Full Text Available [...] Abstract in english The aim of this paper was to analyze the historical approaches to the periodic table in general chemistry textbooks used in Brazilian universities in the twentieth century. Textbooks were qualitatively analyzed according to the following criteria: position of the discussion about the periodic table [...] in the book; presence or absence of a specific chapter on the subject; presentation of attempts to classify chemical elements before Mendeleev; presentation of the construction process of the periodic table by Mendeleev; identification of problems in the original table; discussion of Mendeleev's predictions about unknown elements; organization of the periodic table; periodic properties presented and discussed; and the enunciation of the periodic law. The analysis revealed different approaches at specific periods of the twentieth century, from more descriptive approaches to emphasis on attempts to explain the periodic table in terms of atomic orbitals. These changes point to different ways of understanding chemistry during the period studied.
Low Power Long Period Magnetotelluric System
Narod, B. B.; Bennest, J. R.; Booker, J. R.
We have constructed a new MT system for periods longer than 1 second that uses substantially less power and is considerably easier to deploy than predecessors, such as the Geological Survey of Canada [GSC] Long Period Intelligent Magnetotelluric System [LIMS]. Technical aspects of these new systems include: Fully watertight; light weight [5 kg w/o magnetometer head], Eurocard card cage, 1.7 watt power consumption - 140mA @ 12vdc, built-in solar panel charge controller, GPS-disciplined timekeeping accurate to 1ms, 24-bit 8 Hz Analog to Digital conversion, data storage on a PCMCIA flash disk [85M and up], magnetic field: +/- 80,000 nT range with 10pT resolution, electric field ch: +/- 200 mv with sub-microvolt useful resolution. A setup program automatically handles most deployment tasks including recording site location and data start time. Data are logged in files that begin at hour marks and are of one-hour duration. They are thus automatically synchronous at an array of instruments. Data retrieval consists of moving a PCMCIA card from the data logger to a laptop computer. A revision of this system is already in progress. It will feature PC104 card formats and will be lighter, smaller and have even lower power consumption. Ten of these systems were deployed for the first time during August and September 2001, in Argentina. Sample data from these deployments will be shown.
The Alpha-Mendeleev Magmatic Province, Arctic Ocean: A New Synthesis
Vogt, P. R.; Jung, W.; Jakobsson, M.; Mayer, L.; Williamson, M.
Since the 1970s, the Alpha-Mendeleev Ridge (AMR) has generally been considered oceanic, with a thickened (ca. 35km) crustal or/and abnormally low-density mantle root, a "hotspot"-type, Cretaceous-aged aseismic ridge perhaps generated by the controversial Iceland hotspot. The high-amplitude AMR aeromagnetic anomalies (locally > 1000nT) are sublinear, largely correlated with ▒20mgal free-air gravity anomalies and bathymetric/basement topography. Such correlation is consistent with most magma emplaced during the long Cretaceous normal polarity interval (120-83Ma). (Present basement topography may post-date the magmatism). Based on multibeam bathymetry from the 2003 Healy expedition and published sources, we synthesize the mid-Cretaceous-age Alpha-Mendeleev Ridge (AMR) complex, a ca.300-700km X 1500km Arctic Basin rise (>700,000 km sq; mininum basement depths 10 million km3 excess mafic materials under the AMR, a volume exceeded only by the Ontong Java Plateau. Multibeam bathymetry collected on USCGC Healy in 2003 discovered probable volcanic seamounts in the Northwind Basin and mapped a seamount off the tip of the Chukchi Rise. We suggest these edifices, and linear aeromagnetic anomalies - suggesting major dikes crossing the continental Chukchi Rise - are part of the same extensive igneous episode that created the AMR. Other evidence for a more extensive "AMR Magmatic Province" (AMRMP) includes: 1) Basement peaks/seamounts in the Sever and Peary spurs and Nautilus and Stefansson basins, which together would bring the total AMRMP area to ca. 10 million km2; 2) Aeromagnetics, showing AMR-type magnetic and gravity anomaly patterns well beyond the AMR; and 3) Mafic rocks (125-89Ma) of the Sverdrup Basin Magmatic Province (SBMP), as shown by M-C. Williamson and her colleagues. The northeastern SBMP adjoins the polar margin, not far from the poorly dated AMR. The two final SBMP igneous episodes are coeval with AMR magmatism, and comprise ferrogabbroic sills and thin successions of ferrobasaltic lavas, a clue that high AMR magnetic anomalies may have a similar origin, as first suggested by Williamson and Van Wagoner in 1985. However, simple amplitude comparison would be incorrect - the higher geomagnetic field intensity near the poles, shallow AMR basement, high AMR basement relief, and possibly stronger middle Cretaceous dipole would all contribute to increasing anomaly amplitudes relative to typical Cenozoic oceanic crust created at lower latitudes. We hypothesize that the AMRMP constitutes a vast mass of anomalously fractionated, highly magnetized FeTi basalts and ferrograbbros. However,we cannot exclude the possibility of admixed continental crust, especially at the Siberian end of the AMR, and only deep drilling into AMR basement will provide firm answers.
Alguns aspectos hist¾ricos da classificańŃo peri¾dica dos elementos quĒmicos / Some historical aspects of the periodic classification of the chemical elements
Scientific Electronic Library Online (English)
Mario, Tolentino; Romeu C., Rocha-Filho; Aķcio Pereira, Chagas.
Full Text Available [...] Abstract in english A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their prope [...] r periodic classification are also presented.
Alguns aspectos hist¾ricos da classificańŃo peri¾dica dos elementos quĒmicos Some historical aspects of the periodic classification of the chemical elements
Directory of Open Access Journals (Sweden)
Mario Tolentino
Full Text Available A history of the periodic table of the elements is presented, from the first tentative classifications, passing through Meyer and Mendeleev, up to recent speculations on super-heavy elements still to be synthesized. Many of the discussions and discoveries related to chemical elements and their proper periodic classification are also presented.
Periodic Table of the Elements in the Perspective of Artificial Neural Networks
Lemes, Mauricio R.; Dal Pino, Arnaldo
Although several chemical elements were not known by end of the 19th century, Mendeleev came up with an astonishing achievement, the periodic table of elements. He was not only able to predict the existence of (then) new elements, but also to provide accurate estimates of their chemical and physical properties. This is a profound example of theģ
On periodic orbits in discrete-time cascade systems
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Xiao-Song Yang
Full Text Available We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.
On periodic orbits in discrete-time cascade systems
Xiao-Song Yang; Huimin Li
We present some results on existence, minimum period, number of periodic orbits, and stability of periodic orbits in discrete-time cascade systems. Some examples are presented to illustrate these results.
Estimates on the minimal period for periodic solutions of nonlinear second order Hamiltonian systems
International Nuclear Information System (INIS)
In this paper, we prove a sharper estimate on the minimal period for periodic solutions of autonomous second order Hamiltonian systems under precisely Rabinowitz' superquadratic condition. (author). 20 refs, 1 fig
Periodic solutions of a forced system with hysteresis.
Drew, J. H.
Hysteresis damping arising in an oscillatory system due to the phenomenon of slip damping analyzed by Goodman and Klumpp (1956) is considered. An idealized physical model is proposed, and the existence of certain periodic motions is investigated in a system with small forcing which are near the largest periodic motion in a corresponding unforced system. Periodic solutions of the forced system are obtained.-
Dynamical Equations For The Period Vectors In A Periodic System Under Constant External Stress
Liu, Gang
The purpose of this paper is to derive the dynamical equations for the period vectors of a periodic system under constant external stress. The explicit starting point is Newton's second law applied to halves of the system. Later statistics over indistinguishable translated states and forces associated with transport of momentum are applied to the resulting dynamical equations. In the final expressions, the period vectors are driven by the imbalance between internal and exter...
Temperature profile data collected aboard the USCGC Polar Star in support of investigations of the influence of the Mendeleev Ridge and Chukchi Borderland on the large-scale circulation of the Arctic Ocean, August - September 2002 (NODC Accession 0002697)
National Oceanic and Atmospheric Administration, Department of Commerce Ś This is an archive of data of 47 distinct XBT casts taken at 41 locations in the Mendeleev Ridge and Chukchi Borderland region of the Arctic between 22nd August and...
Robot Head Stabilization During Periodic Locomotion Using Adaptive Dynamical Systems
Gay, Se?bastien; Ijspeert, Auke; Santos-victor, Jose?
We present a gaze stabilization system using only visual information as feedback for a self tuning dynamical system. We describe how the dynamical system tunes its internal parameters to those of the optical ?ow information to generate compensatory commands. We show that the system can be applied to head stabilization during periodic locomotion, but also to tracking periodically moving objects.
On the prescribed-period problem for autonomous Hamiltonian systems
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A. A. Zevin
Full Text Available systems are considered. Lower bounds for the number of periodic solutions with a prescribed minimal period are obtained. These bounds are expressed in terms of the numbers of frequencies corresponding to the critical points of the Hamiltonian. Results are based on a global analysis of families of periodic solutions emanating from these points.
William C. Robertson, Ph.D.
In thinking about a title for this chapter, the word periodicity came to mind. I was sure this had some kind of pop culture reference. After discussing this with my wife, we figured I was thinking of synchronicity, which is a reference to music by the band, The Police. Looking the word Periodicity up on the internet, I found that I was, in fact, a science geek and had not made a hip reference. Periodicity refers mainly to the Periodic Table, which is a focus of this chapter. No music, just science.
MDM: A Mode Diagram Modeling Framework for Periodic Control Systems
Wang, Zheng; Pu, Geguang; Qin, Shenchao; Li, Jianwen; Larsen, Kim G.; Madsen, Jan; Gu, Bin; He, Jifeng
Periodic control systems used in spacecrafts and automotives are usually period-driven and can be decomposed into different modes with each mode representing a system state observed from outside. Such systems may also involve intensive computing in their modes. Despite the fact that such control systems are widely used in the above-mentioned safety-critical embedded domains, there is lack of domain-specific formal modelling languages for such systems in the relevant industry...
Adaptive Scheduling in Real-Time Systems Through Period Adjustment
Dwivedi, Shri Prakash
Real time system technology traditionally developed for safety critical systems, has now been extended to support multimedia systems and virtual reality. A large number of real-time application, related to multimedia and adaptive control system, require more flexibility than classical real-time theory usually permits. This paper proposes an efficient adaptive scheduling framework in real-time systems based on period adjustment. Under this model periodic task can change their...
Effective Hamiltonian approach to periodically perturbed quantum optical systems
International Nuclear Information System (INIS)
We apply the method of Lie-type transformations to Floquet Hamiltonians for periodically perturbed quantum systems. Some typical examples of driven quantum systems are considered in the framework of this approach and corresponding effective time dependent Hamiltonians are found
Computer-based Periodicals Management System in SAC Library
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D.R. Patel,
Full Text Available The paper discusses the efforts made for a Periodicals Management System developed and designed for implementation in SAC Library, using DBASE III software. It briefly describes the computer programmes in PMS and highlights the present system which is implemented by using 'LIBSYS', a comprehensive library software package and a multi-user system on Pentium system, under Unix environment.
Asymptotic stability on slow time scales from periodic systems
International Nuclear Information System (INIS)
Asymptotic stability for a periodic system of ordinary differential equations with a small parameter is shown to follow from the stability of the corresponding iterated-average system. Applications are made to biological systems experiencing varying seasonal factors, to large scale dynamical systems that are principally irrotational and to nuclear reactor dynamics. 7 refs
Optimization of maintenance periodicity of complex of NPP safety systems
International Nuclear Information System (INIS)
The analysis of the positive and negative aspects connected to maintenance of the safety systems equipment which basically is in a standby state is executed. Tests of systems provide elimination of the latent failures and raise their reliability. Poor quality of carrying out the tests can be a source of the subsequent failures. Therefore excess frequency of tests can result in reducing reliability of safety systems. The method of optimization of maintenance periodicity of the equipment taking into account factors of its reliability and restoration procedures quality is submitted. The unavailability factor is used as a criterion of optimization of maintenance periodicity. It is offered to use parameters of reliability of the equipment and each of safety systems of NPPs received at developing PSA. And it is offered to carry out the concordance of maintenance periodicity of systems within the NPP maintenance program taking into account a significance factor of the system received on the basis of the contribution of system in CDF. Basing on the submitted method the small computer code is developed. This code allows to calculate reliability factors of a separate safety system and to determine optimum maintenance periodicity of its equipment. Optimization of maintenance periodicity of a complex of safety systems is stipulated also. As an example results of optimization of maintenance periodicity at Zaporizhzhya NPP are presented. (author)
Periodic solutions of nonautonomous differential systems modeling obesity population
Energy Technology Data Exchange (ETDEWEB)
Arenas, Abraham J. [Departamento de Matematicas y Estadistica, Universidad de Cordoba Monteria (Colombia)], E-mail: firstname.lastname@example.com; Gonzalez-Parra, Gilberto [Departamento de Calculo, Universidad de los Andes, Merida (Venezuela, Bolivarian Republic of)], E-mail: firstname.lastname@example.com; Jodar, Lucas [Instituto de Matematica Multidisciplinar, Universidad Politecnica de Valencia Edificio 8G, 2o, 46022 Valencia (Spain)], E-mail: firstname.lastname@example.com
In this paper we study the periodic behaviour of the solutions of a nonautonomous model for obesity population. The mathematical model represented by a nonautonomous system of nonlinear ordinary differential equations is used to model the dynamics of obese populations. Numerical simulations suggest periodic behaviour of subpopulations solutions. Sufficient conditions which guarantee the existence of a periodic positive solution are obtained using a continuation theorem based on coincidence degree theory.
Equilibrium states of generic quantum systems subject to periodic driving.
Lazarides, Achilleas; Das, Arnab; Moessner, Roderich
When a closed quantum system is driven periodically with period T, it approaches a periodic state synchronized with the drive in which any local observable measured stroboscopically approaches a steady value. For integrable systems, the resulting behavior is captured by a periodic version of a generalized Gibbs ensemble. By contrast, here we show that for generic nonintegrable interacting systems, local observables become independent of the initial state entirely. Essentially, this happens because Floquet eigenstates of the driven system at quasienergy ?(?) consist of a mixture of the exponentially many eigenstates of the undriven Hamiltonian, which are thus drawn from the entire extensive undriven spectrum. This is a form of equilibration which depends only on the Hilbert space of the undriven system and not on any details of its Hamiltonian. PMID:25122254
The periodic system of chemical elements: old and new developments
International Nuclear Information System (INIS)
Some historical facts about the construction of a periodic system of chemical elements are reviewed. The Madelung rule is used to generate an unusual format for the periodic table. Following the work of Byakov, Kulakov, Rumer and Fet, such a format is further refined on the basis of a chain of groups starting with SU(2)xS0(4.2)
Isotropic periodic sum of electrostatic interactions for polar systems
Wu, Xiongwu; Brooks, Bernard R.
Isotropic periodic sum (IPS) is a method to calculate long-range interactions based on homogeneity of simulation systems. Long-range interactions are represented by interactions with isotropic periodic images of a defined local region and can be reduced to short ranged IPS potentials. The original electrostatic three-dimensional (3D)-IPS potential was derived based on a nonpolar homogeneous approximation and its application is limited to nonpolar or weak polar systems. This work derived a pol...
Inverse crystallization if Abrikosov vortex system at periodic pinning
Zyubin, M V; Kashurnikov, V A
The vortex system in the quasi-two-dimensional HTSC plate is considered in the case of the periodic pinning. The M(H) magnetization curves by various values of the external magnetic field and different temperatures are calculated through the Monte Carlo method. It is shown that in the case of the periodic pinning the crystallization of the vortex system is possible by the temperature increase. A number of peculiarities conditioned by the impact of the pinning centers periodic lattice are identified on the magnetization curves. The pictures of the vortex distribution corresponding to various points on the M(H) curve are obtained
Periodic orbits for perturbations of piecewise linear systems
Carmona, Victoriano; Fernßndez-GarcĒa, Soledad; Freire, Emilio
We consider the existence of periodic orbits in a class of three-dimensional piecewise linear systems. Firstly, we describe the dynamical behavior of a non-generic piecewise linear system which has two equilibria and one two-dimensional invariant manifold foliated by periodic orbits. The aim of this work is to study the periodic orbits of the continuum that persist under a piecewise linear perturbation of the system. In order to analyze this situation, we build a real function of real variable whose zeros are related to the limit cycles that remain after the perturbation. By using this function, we state some results of existence and stability of limit cycles in the perturbed system, as well as results of bifurcations of limit cycles. The techniques presented are similar to the Melnikov theory for smooth systems and the method of averaging.
Mechanism of extraction 4th period of periodic system metal ions with carboxylic acids in sulphate systems
International Nuclear Information System (INIS)
Extraction of transition metal ions of the 4th period of Periodic system by carboxylic acids in sulfate systems was studied. It is shown that depending on composition and physicochemical properties of aqueous phase (pH, the type of metal ion, its complexing properties etc.) the solvent extraction may proceed according to two mechanisms: cation-exchange or hydration-solvation. The extraction is more effective in the field of cation-exchange mechanism
Phase control of resonant systems: Interference, chaos and high periodicity
Greenman, J. V.; Pasour, V. B.
Abstract Much progress has been made in understanding the effect of periodic forcing on epidemiological and ecological systems when that forcing acts on just one part of the system. Much less is known about situations in which several parts of the system are affected. In this case the interaction between the impacts of the different forcing components can lead to reinforcement of system responses or to their interference. This interference phenomenon is significant if some forcing ...
Applying Adjacent Hyperbolas to Calculation of the Upper Limit of the Periodic Table of Elements, with Use of Rhodium
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Khazan A.
Full Text Available In the earlier study (Khazan A. Upper Limit in Mendeleev's Periodic Table - Element No.155. 2nd ed., Svenska fysikarkivet, Stockholm, 2010 the author showed how Rhodium can be applied to the hyperbolic law of the Periodic Table of Elements in order to calculate, with high precision, all other elements conceivable in the Table. Here we obtain the same result, with use of fraction linear functions (adjacent hyperbolas.
The distribution of period ratios in Kepler planetary systems
Steffen, Jason H.; Hwang, Jason A.
Kepler's multi-planet systems are a valuable tool to understand the architectures and dynamics of the inner parts of planetary systems. I present an analysis of the distribution of orbital period ratios from candidate systems identified in the Quarter 8 catalog (Burke et al. 2014). This distribution is corrected for the effects of geometric transit probabilities and the completeness of the data reduction pipeline. We find that the distribution of period ratios falls as a power law with exponent -1.26 ▒ 0.05. We also identify a new, statistically significant feature near a period ratio of 2.2. These observations may provide insights into the formation and evolution of these systems.
Pseudo analytical solution to time periodic stiffness systems
International Nuclear Information System (INIS)
An analytical form of state transition matrix for a system of equations with time periodic stiffness is derived in order to solve the free response and also allow for the determination of system stability and bifurcation. A pseudo-closed form complete solution for parametrically excited systems subjected to inhomogeneous generalized forcing is developed, based on the Fourier expansion of periodic matrices and the substitution of matrix exponential terms via LagrangeŚSylvester theorem. A Mathieu type of equation with large amplitude is presented to demonstrate the method of formulating state transition matrix and Floquet multipliers. A two-degree-of-freedom system with irregular time periodic stiffness characterized by spiral bevel gear mesh vibration is presented to find forced response in stability and instability. The obtained results are presented and discussed. (general)
Bifurcations, Period doubling and chaos in clarinet-like systems
Maganza, Christian; Causse?, Rene?; Laloe?, Franck
Wind instruments provide interesting hydrodynamical systems where non-linearities are important but well localized. A simple analysis shows that these systems should undergo Feignebaum-type route to chaos, with a cascade of period doublings. Experiments have been performed fo confirm these predictions
Periodically driven underdamped periodic and washboard potential systems: dynamical states and stochastic resonance.
Reenbohn, W L; Pohlong, S S; Mahato, Mangal C
We have studied the motion of an underdamped Brownian particle in (i) a bistable periodic potential and (ii) washboard potentials subjected to a sinusoidal external field. The particles are shown to be effectively in two dynamical states of their trajectories with distinct amplitudes and phase relationship with the external drive. These dynamical states are stable with fixed energies at low temperatures, but transitions between them take place as the temperature is increased. The average input energy loss to the environment per period of the drive shows a stochastic resonance (SR) peak as a function of temperature for the underdamped system potentials studied. The occurrence of SR in these systems is explained using the statistics of transitions between the two dynamical states. PMID:22587075
The period ratio distribution of Kepler's candidate multiplanet systems
Steffen, Jason H.; Hwang, Jason A.
We calculate and analyse the distribution of period ratios observed in systems of Kepler exoplanet candidates including studies of both adjacent planet pairs and all planet pairs. These distributions account for both the geometrical bias against detecting more distant planets and the effects of incompleteness due to planets missed by the data reduction pipeline. In addition to some of the known features near first-order mean-motion resonances (MMRs), there is a significant excess of planet pairs with period ratios near 2.2. The statistical significance of this feature is assessed using Monte Carlo simulation. We also investigate the distribution of period ratios near first-order MMR and compare different quantities used to measure this distribution. We find that beyond period ratios of ś2.5, the distribution of all period ratios follows a power law with an exponent -1.26 ▒ 0.05. We discuss implications that these results may have on the formation and dynamical evolution of Kepler-like planetary systems-systems of sub-Neptune/super-Earth planets with relatively short orbital periods.
Development of Seismic Isolation Systems Using Periodic Materials
Energy Technology Data Exchange (ETDEWEB)
Mo, Yi-Lung; Stokoe, Kenneth H.; Perkins, Judy; Tang, Yu
Advanced fast nuclear power plants and small modular fast reactors are composed of thin-walled structures such as pipes; as a result, they do not have sufficient inherent strength to resist seismic loads. Seismic isolation, therefore, is an effective solution for mitigating earthquake hazards for these types of structures. Base isolation, on which numerous studies have been conducted, is a well-defined structure protection system against earthquakes. In conventional isolators, such as high-damping rubber bearings, lead-rubber bearings, and friction pendulum bearings, large relative displacements occur between upper structures and foundations. Only isolation in a horizontal direction is provided; these features are not desirable for the piping systems. The concept of periodic materials, based on the theory of solid-state physics, can be applied to earthquake engineering. The periodic material is a material that possesses distinct characteristics that prevent waves with certain frequencies from being transmitted through it; therefore, this material can be used in structural foundations to block unwanted seismic waves with certain frequencies. The frequency band of periodic material that can filter out waves is called the band gap, and the structural foundation made of periodic material is referred to as the periodic foundation. The design of a nuclear power plant, therefore, can be unified around the desirable feature of a periodic foundation, while the continuous maintenance of the structure is not needed. In this research project, three different types of periodic foundations were studied: one-dimensional, two-dimensional, and three-dimensional. The basic theories of periodic foundations are introduced first to find the band gaps; then the finite element methods are used, to perform parametric analysis, and obtain attenuation zones; finally, experimental programs are conducted, and the test data are analyzed to verify the theory. This procedure shows that the periodic foundation is a promising and effective way to mitigate structural damage caused by earthquake excitation.
Phase control of resonant systems: interference, chaos and high periodicity.
Greenman, J V; Pasour, V B
Much progress has been made in understanding the effect of periodic forcing on epidemiological and ecological systems when that forcing acts on just one part of the system. Much less is known about situations in which several parts of the system are affected. In this case the interaction between the impacts of the different forcing components can lead to reinforcement of system responses or to their interference. This interference phenomenon is significant if some forcing components are anthropogenic for then management might be able to exercise sufficient control to bring about suppression of undesirable aspects of the forcing, for example resonant amplification and the problems this can cause. We set out the algebraic theory when forcing is weak and illustrate by example what can happen when forcing is strong enough to create subharmonics and chaotic states. Phase is the key control variable that can bring about interference, advantageously shift nonlinear response curves and create periodic states out of chaos. The phenomenon in which high period fluctuations appear to be generated by low period forcing is examined and different mechanisms compared in a two-strain epidemiological model. The effect of noise as a source of high period fluctuations is also considered. PMID:21397609
Many-body energy localization transition in periodically driven system
D'Alessio, Luca; Polkovnikov, Anatoli
According to the second law of thermodynamics the total entropy and energy of a system is increased during almost any dynamical process. Notable exceptions are known in noninteracting systems of particles moving in periodic potentials. Here the phenomenon of dynamical localization can prevent heating beyond certain threshold. However, it was believed that driven ergodic systems will always heat without bound. Here, on the contrary, we report strong evidence of dynamical localization transition in periodically driven ergodic systems in the thermodynamic limit. This phenomenon is reminiscent of many-body localization in energy space. We report numerical evidence based on exact diagonalization of small spin chains and theoretical arguments based on the Magnus expansion. Our findings are valid for both classical and quantum systems.
Long period seismic ground motions for isolation systems
International Nuclear Information System (INIS)
In this paper numerical simulations of long period strong ground motions are calculated based on theoretical seismological models of the seismic source and wave propagation. The method includes both near-field and far-field terms and surface waves as well as body waves which allows valid simulations at both short and large distances. Long period ground motions for magnitude 6.75 and magnitude 8.0 events are computed at distances of 3 to 30 km. The resulting response spectral displacements are compared to the SEAOC 1990 spectrum for base-isolated system. At a period of 2 seconds, the SEAOC spectrum is close to the spectrum for a magnitude 8.0 earthquake. However, at a period of 5 seconds, the SEAOC spectrum is much larger than the simulated notions even for a magnitude 8 event
Many-body energy localization transition in periodically driven systems
International Nuclear Information System (INIS)
According to the second law of thermodynamics the total entropy of a system is increased during almost any dynamical process. The positivity of the specific heat implies that the entropy increase is associated with heating. This is generally true both at the single particle level, like in the Fermi acceleration mechanism of charged particles reflected by magnetic mirrors, and for complex systems in everyday devices. Notable exceptions are known in noninteracting systems of particles moving in periodic potentials. Here the phenomenon of dynamical localization can prevent heating beyond certain threshold. The dynamical localization is known to occur both at classical (Fermi¢Ulam model) and at quantum levels (kicked rotor). However, it was believed that driven ergodic systems will always heat without bound. Here, on the contrary, we report strong evidence of dynamical localization transition in both classical and quantum periodically driven ergodic systems in the thermodynamic limit. This phenomenon is reminiscent of many-body localization in energy space. -- Highlights: ĢA dynamical localization transition in periodically driven ergodic systems is found. ĢThis phenomenon is reminiscent of many-body localization in energy space. ĢOur results are valid for classical and quantum systems in the thermodynamic limit. ĢAt critical frequency, the short time expansion for the evolution operator breaks down. ĢThe transition is associated to a divergent time scale
Numerical analysis on periodic response of nonsmooth dynamic systems
Hu, Haiyan
The periodic response analysis of a nonlinear dynamic system, which is of great significant in engineering, is usually carried out by using numerical methods because of high dimension and complicated characters of the system. The current well-known numerical schemes like shooting and incremental harmonic balancing, however, cannot cope with the engineering systems with nonsmooth physical factors, such as elastoplasticity, clearance and dry friction, and also fail to get the strong nonlinear periodic response of smooth dynamic systems sometimes. In the paper the author analyzes the above shortcomings and points out that they result from the explicit or implicit Newton iteration in the schemes. The paper presents eight new schemes based on quasi-Newton iteration or unconstrained function minimization to improve the shooting and the incremental harmonic balancing. The convergence, accuracy and computation efficiency of these new schemes are examined and four of them are suggested for engineering use.
Universality of the topology of period doubling dynamical systems
International Nuclear Information System (INIS)
The evolution of the topology of the invariant manifolds of the attractors of 3-D autonomous dynamical systems during period doubling is shown to be universal. The overall topology of the nth attractor is shown to depend only on the topology of the first attractor at birth
Existence of periodic solutions for nonlinear Lienard systems
Directory of Open Access Journals (Sweden)
Wan Se Kim
Full Text Available We prove the existence and multiplicity of periodic solutions for nonlinear Lienard System of the type x├ó┬Ć┬│(t+ddt[├ó┬ł┬ćF(x(t]+g(x(t+h(t,x(t=e(t under various conditions upon the functions g, h and e.
The period ratio distribution of Kepler's candidate multiplanet systems
Steffen, Jason H
We calculate and analyze the distribution of period ratios observed in systems of Kepler exoplanet candidates including studies of both adjacent planet pairs and all planet pairs. These distributions account for both the geometrical bias against detecting more distant planets and the effects of incompleteness due to planets missed by the data reduction pipeline. In addition to some of the known features near first-order mean-motion resonances (MMR), there is a significant excess of planet pairs with period ratios near 2.2. The statistical significance of this feature is assessed using Monte Carlo simulation. We also investigate the distribution of period ratios near first-order MMR and compare different quantities used to measure this distribution. We find that beyond period ratios of ~2.5, the distribution of all period ratios follows a power-law with an exponent -1.26 +/- 0.05. We discuss implications that these results may have on the formation and dynamical evolution of Kepler-like planetary systems---sys...
Borides of the group 1 metals of the periodic system
International Nuclear Information System (INIS)
The borides of alkali metals (lithium, sodium, potassium) and the metals of a copper subgroup (copper, silver, gold) are described. Consideration is given to the crystalline structure and state diagrams of the metal systems within the first group of the Periodic Table with boron. Existence, formation conditions and physico-chemical properties of binary boride phases are characterized. Conclusion is made as to the absence of interaction between boron and silver. Information on the interaction between gold and boron is scanty and conflicting. Methods are described suitable for the production of the borides of the metals within the first group of the Periodic Table
Continuation and bifurcation analysis of a periodically forced excitable system.
Croisier, H; Dauby, P C
The response of an excitable cell to periodic electrical stimulation is modeled using the FitzHugh-Nagumo (FHN) system submitted to a gaussian-shaped pacing, the width of which is small compared with the action potential duration. The influence of the amplitude and the period of the stimulation is studied using numerical continuation and bifurcation techniques (AUTO97 software). Results are discussed in the light of prior experimental and theoretical findings. In particular, agreement with the documented behavior of periodically stimulated cardiac cells and squid axons is discussed. As previously reported, we find many different "M:N" periodic solutions, period-doubling sequences leading to seemingly chaotic regimes, and bistability phenomena. In addition, the use of continuation techniques has allowed us to track unstable solutions of the system and thus to determine how the different stable rhythms are connected with each other in a bifurcation diagram. Depending on the stimulus amplitude, the aspect of the bifurcation diagram with the stimulus period as main varying parameter can vary from very simple to very complex. In its most developed structure, this bifurcation diagram consists of a main "tree" of period-2(P) branches, where the 1:1, 1:0, 2:2, 2:1,... rhythms are located, and of several closed loops made up of period-{N x 2(P)} branches (N>2), isolated from each other and from the main tree. It is mainly on such loops that N:1 rhythms (N>2) on one hand, and N:N-1 or Wenckebach rhythms (N>2) on the other hand, are located. Stable M:N and M:N-1 rhythms (M>or=N) can be found on the same branch of solutions. They are separated by a region of unstable solutions at small stimulus amplitudes, but this region shrinks gradually as the stimulus amplitude is raised, until it finally disappears. We believe that this property is related to the excitability characteristics of the FHN system. It would be interesting to know if it has any correspondence in the behavior of real excitable cells. PMID:17337277
Dynamic steady-state of periodically-driven quantum systems
Yudin, V I; Basalaev, M Yu; Kovalenko, D
Using the density matrix formalism, we prove an existence theorem of the periodic steady-state for an arbitrary periodically-driven system. This state has the same period as the modulated external influence, and it is realized as an asymptotic solution ($t$$\\to$$+\\infty$) due to relaxation processes. The presented derivation simultaneously contains a simple computational algorithm non-using both Floquet and Fourier theories, i.e. our method automatically guarantees a full account of all frequency components. The description is accompanied by the examples demonstrating a simplicity and high efficiency of our method. In particular, for three-level $\\Lambda$-system we calculate the lineshape and field-induced shift of the dark resonance formed by the field with periodically modulated phase. For two-level atom we obtain the analytical expressions for signal of the direct frequency comb spectroscopy with rectangular light pulses. In this case it was shown the radical dependence of the spectroscopy lineshape on pul...
Binary systems: implications for outflows & periodicities relevant to masers
Singh, Nishant K
Bipolar molecular outflows have been observed and studied extensively in the past, but some recent observations of periodic variations in maser intensity pose new challenges. Even quasi-periodic maser flares have been observed and reported in the literature. Motivated by these data, we have tried to study situations in binary systems with specific attention to the two observed features, i.e., the bipolar flows and the variabilities in the maser intensity. We have studied the evolution of spherically symmetric wind from one of the bodies in the binary system, in the plane of the binary. Our approach includes the analytical study of rotating flows with numerical computation of streamlines of fluid particles using PLUTO code. We present the results of our findings assuming simple configurations, and discuss the implications.
Periodic orbits of hybrid systems and parameter estimation via AD
International Nuclear Information System (INIS)
Rhythmic, periodic processes are ubiquitous in biological systems; for example, the heart beat, walking, circadian rhythms and the menstrual cycle. Modeling these processes with high fidelity as periodic orbits of dynamical systems is challenging because: (1) (most) nonlinear differential equations can only be solved numerically; (2) accurate computation requires solving boundary value problems; (3) many problems and solutions are only piecewise smooth; (4) many problems require solving differential-algebraic equations; (5) sensitivity information for parameter dependence of solutions requires solving variational equations; and (6) truncation errors in numerical integration degrade performance of optimization methods for parameter estimation. In addition, mathematical models of biological processes frequently contain many poorly-known parameters, and the problems associated with this impedes the construction of detailed, high-fidelity models. Modelers are often faced with the difficult problem of using simulations of a nonlinear model, with complex dynamics and many parameters, to match experimental data. Improved computational tools for exploring parameter space and fitting models to data are clearly needed. This paper describes techniques for computing periodic orbits in systems of hybrid differential-algebraic equations and parameter estimation methods for fitting these orbits to data. These techniques make extensive use of automatic differentiation to accurately a automatic differentiation to accurately and efficiently evaluate derivatives for time integration, parameter sensitivities, root finding and optimization. The boundary value problem representing a periodic orbit in a hybrid system of differential algebraic equations is discretized via multiple-shooting using a high-degree Taylor series integration method (GM00, Phi03). Numerical solutions to the shooting equations are then estimated by a Newton process yielding an approximate periodic orbit. A metric is defined for computing the distance between two given periodic orbits which is then minimized using a trust-region minimization algorithm (DS83) to find optimal fits of the model to a reference orbit (Cas04). There are two different yet related goals that motivate the algorithmic choices listed above. The first is to provide a simple yet powerful framework for studying periodic motions in mechanical systems. Formulating mechanically correct equations of motion for systems of interconnected rigid bodies, while straightforward, is a time-consuming error prone process. Much of this difficulty stems from computing the acceleration of each rigid body in an inertial reference frame. The acceleration is computed most easily in a redundant set of coordinates giving the spatial positions of each body: since the acceleration is just the second derivative of these positions. Rather than providing explicit formulas for these derivatives, automatic differentiation can be employed to compute these quantities efficiently during the course of a simulation. The feasibility of these ideas was investigated by applying these techniques to the problem of locating stable walking motions for a disc-foot passive walking machine (CGMR01, Gar99, McG91). The second goal for this work was to investigate the application of smooth optimization methods to periodic orbit parameter estimation problems in neural oscillations. Others (BB93, FUS93, VB99) have favored non-continuous optimization methods such as genetic algorithms, stochastic search methods, simulated annealing and brute-force random searches because of their perceived suitability to the landscape of typical objective functions in parameter space, particularly for multi-compartmental neural models. Here we argue that a carefully formulated optimization problem is amenable to Newton-like methods and has a sufficiently smooth landscape in parameter space that these methods can be an efficient and effective alternative. The plan of this paper is as follows. In Section 1 we provide a definition of hybrid systems that is the basis for
Periodically Driven Quantum Systems: Effective Hamiltonians and Engineered Gauge Fields
Goldman, N.; Dalibard, J.
Driving a quantum system periodically in time can profoundly alter its long-time dynamics and trigger topological order. Such schemes are particularly promising for generating nontrivial energy bands and gauge structures in quantum-matter systems. Here, we develop a general formalism that captures the essential features ruling the dynamics: the effective Hamiltonian, but also the effects related to the initial phase of the modulation and the micromotion. This framework allows for the identification of driving schemes, based on general N-step modulations, which lead to configurations relevant for quantum simulation. In particular, we explore methods to generate synthetic spin-orbit couplings and magnetic fields in cold-atom setups.
Signatures of resonant terrestrial planets in long-period systems
Kennedy, Gareth F
The majority of extrasolar planets discovered to date have significantly eccentric orbits, some if not all of which may have been produced through planetary migration. During this process, any planets interior to such an orbit would therefore have been susceptible to resonance capture, and hence may exhibit measurable orbital period variations. Here we summarize the results of our investigation into the possibility of detecting low-mass planets which have been captured into the strong 2:1 resonance. Using analytical expressions together with simulated data we showed that it is possible to identify the existence of a low-mass companion in the internal 2:1 resonance by estimating the time-dependant orbital period for piecewise sections of radial velocity data. This works as long as the amplitude of modulation of the orbital period is greater than its uncertainty, which in practice means that the system should not be too close to exact resonance. Here we provide simple expressions for the libration period and th...
Application of Periodic 3DPCM for Core Monitoring System
Energy Technology Data Exchange (ETDEWEB)
Jeong, Wi-Soo; Lee, Hae-Chan; Kim, Hyeong-Seog; Lee, Chang-Kue; Park, Sang-weon [KEPCO NF, Daejeon (Korea, Republic of); Baek, Jin-su [KHNP Hanul Nuclear Power, Uljin (Korea, Republic of)
The OASIS (Online core Analysis and Simulation System) was developed for WH type PWR which has movable in-core detector. 3DPCM (3D Power Connection Method) was also developed to measure 3D core power distribution using the fixed in-core detector signals and tested for KSNP (Korea Standard Nuclear Plant) such as OPR1000 and APR1400. According to previous study, 3DPCM coupling with neutronics code shows high accuracy. However, this method requires the neutronics code results at each calculation. Therefore, the long calculation time makes it impractical in the online monitoring system requiring the real-time 3D power distribution. In this paper, the 3DPCM based alternative methodology which called periodic 3DPCM is proposed to reduce the calculation time within the reasonable accuracy. The periodic 3DPCM is proposed to reduce the number of neutronics calculation with reasonable accuracy for the application to the online monitoring system development. The periodic 3DPCM is analyzed by 3 cases of sensitivity studies. The errors for the results of power changing operation, ASI changing simulation, and lead control rod insertion are bounded in 0.25%, 1.07%, and 1.15%, respectively. If the update time is shorten as 1 hour, the errors for power changing operation and ASI changing simulation are bounded in 0.07% and 0.56%, respectively. As a result, the update time of 1 hour and prompt update at 30% control rod position change are reasonable considering both conservativeness and effectiveness to update the prediction values. OASIS program utilizing periodic 3DPCM is verified using the plant measurement data and snapshot files which were generated during 45 days operation.
Averaging of time-periodic systems without a small parameter
Chekroun, Mickaļl D; Roux, Jean; Varadi, Ferenc
In this article, we present a new approach to averaging in non-Hamiltonian systems with periodic forcing. The results here do not depend on the existence of a small parameter. In fact, we show that our averaging method fits into an appropriate nonlinear equivalence problem, and that this problem can be solved formally by using the Lie transform framework to linearize it. According to this approach, we derive formal coordinate transformations associated with both first-order and higher-order averaging, which result in more manageable formulae than the classical ones. Using these transformations, it is possible to correct the solution of an averaged system by recovering the oscillatory components of the original non-averaged system. In this framework, the inverse transformations are also defined explicitly by formal series; they allow the estimation of appropriate initial data for each higher-order averaged system, respecting the equivalence relation. Finally, we show how these methods can be used for identifyi...
Periodic dynamic systems for infected hosts and mosquitoes
Directory of Open Access Journals (Sweden)
Oliva W. M.
Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.
Dimension Reduction Near Periodic Orbits of Hybrid Systems
Burden, Samuel; Sastry, S Shankar
When the Poincar\\'{e} map associated with a periodic orbit of a hybrid dynamical system has constant-rank iterates, we demonstrate the existence of a constant-dimensional invariant subsystem near the orbit which attracts all nearby trajectories in finite time. This result shows that the long-term behavior of a hybrid model with a large number of degrees-of-freedom may be governed by a low-dimensional smooth dynamical system. The appearance of such simplified models enables the translation of analytical tools from smooth systems-such as Floquet theory-to the hybrid setting and provides a bridge between the efforts of biologists and engineers studying legged locomotion.
The period distribution of eclipsing and spectroscopic binary systems. I
International Nuclear Information System (INIS)
The authors analyse the period distribution of eclipsing and spectroscopic binary systems, using various methods to take into account selection effects on observational data, with the purpose of deriving the actual distribution curve. The discussion of results shows the presence of some secondary maxima in the distribution which are probably of a non-statistical character. They could be regarded as an indirect clue to the discrete nature of the star formation process, according to the spiral density wave theory of galactic evolution by Lin et al. (1969). (Auth.)
Extension of the periodic system: superheavy, superstrange, antimatter nuclei
International Nuclear Information System (INIS)
The extension of the periodic system into various new areas is investigated. Experiments for the synthesis of superheavy elements and the predictions of magic numbers are reviewed. Further on, investigations on hypernuclei and the possible production of antimatter-clusters in heavy-ion collisions are reported. Various versions of the meson field theory serve as effective field theories at the basis of modern nuclear structure and suggest structure in the vacuum which might be important for the production of hyper- and antimatter. (author)
Geological and geochemical criteria for the continental nature of the Mendeleev Rise (the Arctic Ocean) from the data of drilling and dredging of seabed rock material
Morozov, Andrey; Petrov, Oleg; Kremenetskiy, Alexander; Kashubin, Sergey; Rekant, Pavel; Gusev, Eugene; Shokalskiy, Sergey; Shevchenko, Sergey; Sergeev, Sergey; Artyushkov, Eugene
The results are presented of geological and geophysical studies on the Mendeleev Rise at 10 test sites at 79░N to 83░N (expedition "Arktika-2012" in August-September 2012). During the expedition, for the first time, three boreholes were drilled in the bedrocks of the Mendeleev Rise basement at a depth of 1700-2600 m, and more than 20 thousand fragments of seabed rock material were dredged. Among them carbonate-bearing rocks including dolomite with relicts of trilobites and ostracoderms (D3-C) constitute up 65 %. Up to 20% are terrigenous rocks with a predominance of quartz sandstones. Magmatic rocks constitute 10-15% of the samples (including 8% of gabbro-dolerite and 2 % of granite) with 5% of metamorphic rocks. The boreholes revealed magmatic mafic rocks of basalt to basaltic andesite to trachyandesite series (SiO2-48-58% K2O+Na2O-3,4-9,2%) including epigenically altered volcanic breccias. All fragments of magmatic mafic rocks have a similar mineral and chemical composition and are grouped with gabbro dolerite (SiO2-49-51%, K2O+Na2O-2,5-3,0%). Preliminary results of mineralogic, geochemical and of isotopic geochemical (ICP-OEC, ICP-MS, RFA, Sm-Nd, Rb-Sr, EPMA and others) analyses suggest the continental nature of the studied rocks and show a distinct difference from rocks of the Gakkel Ridge in the Eurasian part of the ocean, which are of the oceanic origin. U-Pb dating of zircons from the core rocks and seabed rock material (SIMS SHRIMP II) indicate a wide range of their formation age: 2940-995, 639-385 and 303-203 Ma and thus suggest that they belong to volcanogenic terrigeneous carbonate-bearing bed of the ancient platform composing the floor of Amerasian part of the Arctic Ocean.
Many-Body Localization in Periodically Driven Systems
Ponte, Pedro; Papi?, Z.; Huveneers, Franńois; Abanin, Dmitry A.
We consider disordered many-body systems with periodic time-dependent Hamiltonians in one spatial dimension. By studying the properties of the Floquet eigenstates, we identify two distinct phases: (i) a many-body localized (MBL) phase, in which almost all eigenstates have area-law entanglement entropy, and the eigenstate thermalization hypothesis (ETH) is violated, and (ii) a delocalized phase, in which eigenstates have volume-law entanglement and obey the ETH. The MBL phase exhibits logarithmic in time growth of entanglement entropy when the system is initially prepared in a product state, which distinguishes it from the delocalized phase. We propose an effective model of the MBL phase in terms of an extensive number of emergent local integrals of motion, which naturally explains the spectral and dynamical properties of this phase. Numerical data, obtained by exact diagonalization and time-evolving block decimation methods, suggest a direct transition between the two phases.
Wide aperture periodic lens system for multiple Compton backscattering
Miyahara, Y
Polarized gamma-ray generation by Compton backscattering in a periodic focusing system of electron and laser beams is discussed for the production of polarized positron beam in a linear collider. Circularly polarized CO sub 2 laser beams are focused by an optical lens series and collided with a 5.8 GeV electron beam to generate circularly polarized gamma-rays with 60 MeV at a maximum. In the present work, the basic concept of periodic lens system discussed previously is reconsidered to reduce the laser power required for a gamma-ray yield of 7x10 sup 1 sup 5 gamma/s and the peak laser power density at lenses as much as possible for technical practice. The electron beam is focused by a series of permanent quadrupole magnets with a FODO structure. The power is reduced to six sources with 5.6 kW each, and the peak power density is reduced to 1.4 GW/cm sup 2. These values can be reduced further by using a longer laser pulse length and a damping ring for the electron beam.
Optimal stabilization of unstable periodic orbits embedded in chaotic systems
Scientific Electronic Library Online (English)
C.A., Cruz-Villar.
Full Text Available En este artĒculo se propone un enfoque basado en el flujo gradiente con el prop¾sito de estabilizar ¾rbitas peri¾dicas inestables inmersas en sistemas ca¾ticos. Tal enfoque considera al problema de estabilizaci¾n como un problema de control ¾ptimo, lo cual permite obtener una soluci¾n en lĒnea al pr [...] oblema de interķs, para lo cual se introduce el cßlculo de las sensibilidades de los estados con respecto a la entrada de control. El controlador por retroalimentaci¾n resultante permite estabilizar ¾rbitas peri¾dicas inestables inmersas en ambas clases de sistemas caoticos, con o sin n·mero de Floquet impar. Ademßs, el enfoque propuesto se extiende para identificar el periodo de la ¾rbita peri¾dica inestable a ser estabilizada, en el caso en que este sea desconocido. Se realizan experimentos de simulaci¾n del controlador propuesto, para estabilizar orbitas peri¾dicas inestables de los sistemas de R÷ssler y de Lorenz. Abstract in english A gradient-flow-based approach is proposed in this paper for stabilizing unstable periodic orbits (UPO) embedded in chaotic systems. In order to obtain an on-line stabilizing solution, the stabilization problem is considered to be an optimal control problem, and system state sensitivities with respe [...] ct to the control input are introduced. The resulting feedback controller is able to stabilize UPO embedded in both kind of systems, with or without an odd Floquet number. Moreover, the proposed approach is easily extended to identifying the period of the UPO to be stabilized when it is unknown. Simulation experiments of the proposed controller are carried out on the R÷ssler and the Lorenz systems.
Periodic inspection optimization model for a complex repairable system
International Nuclear Information System (INIS)
This paper proposes a model to find the optimal periodic inspection interval on a finite time horizon for a complex repairable system. In general, it may be assumed that components of the system are subject to soft or hard failures, with minimal repairs. Hard failures are either self-announcing or the system stops when they take place and they are fixed instantaneously. Soft failures are unrevealed and can be detected only at scheduled inspections but they do not stop the system from functioning. In this paper we consider a simple policy where soft failures are detected and fixed only at planned inspections, but not at moments of hard failures. One version of the model takes into account the elapsed times from soft failures to their detection. The other version of the model considers a threshold for the total number of soft failures. A combined model is also proposed to incorporate both threshold and elapsed times. A recursive procedure is developed to calculate probabilities of failures in every interval, and expected downtimes. Numerical examples of calculation of optimal inspection frequencies are given. The data used in the examples are adapted from a hospital's maintenance data for a general infusion pump.
A note on discrete-time dynamical systems under periodic perturbation
Xiaosong Yang; Huimin Li
We present some results on the existence and the minimum period of periodic orbits for discrete-time dynamical systems under periodic perturbation. Some examples are presented to illustrate these results.
Existence and continuation of periodic solutions of autonomous Newtonian systems
Fura, Justyna; Ratajczak, Anna; Rybicki, S?awomir
In this article, we study the existence and the continuation of periodic solutions of autonomous Newtonian systems. To prove the results we apply the infinite-dimensional version of the degree for SO(2)-equivariant gradient operators defined by the third author in Nonlinear Anal. Theory Methods Appl. 23(1) (1994) 83-102 and developed in Topol. Meth. Nonlinear Anal. 9(2) (1997) 383-417. Using the results due to Rabier [Symmetries, Topological degree and a Theorem of Z.Q. Wang, J. Math. 24(3) (1994) 1087-1115] and Wang [Symmetries and calculation of the degree, Chinese Ann. Math. 10 (1989) 520-536] we show that the Leray-Schauder degree is not applicable in the proofs of our theorems, because it vanishes.
A Long-Period Grating Sensor System Monitoring Loads on a Wind Turbine Blade
DEFF Research Database (Denmark)
Glavind, Lars; Buggy, Stephen
We demonstrate the utilization of a blade load sensor system based on two identical Long-Period Gratings in a Mach-Zehnder configuration. The experimental results demonstrate the potential of a Long-Period Grating based load interrogation system.
The Higgs Boson in the Periodic System of Elementary Particles
Directory of Open Access Journals (Sweden)
Ding-Yu Chung
Full Text Available It is proposed that the observed Higgs Boson at the LHC is the Standard Model Higgs boson that adopts the existence of the hidden lepton condensate. The hidden lepton is in the forbidden lepton family, outside of the three lepton families of the Standard Model. Being forbidden, a single hidden lepton cannot exist alone; so it must exist in the lepton condensate as a composite of ?Æ and ?Æ▒ hidden leptons and their corresponding antileptons. The calculated average mass of the hidden lepton condensate is 128.8 GeV in good agreements with the observed 125 or 126 GeV. The masses of the hidden lepton condensate and all elementary particles including leptons, quarks, and gauge bosons are derived from the periodic system of elementary particles. The calculated constituent masses are in good agreement with the observed values by using only four known constants: the number of the extra spatial dimensions in the eleven-dimensional membrane, the mass of electron, the mass of Z boson, and the fine structure constant.
A method to determine the periodic solution of the non-linear dynamics system
Li, Dexin; Xu, Jianxue
In this paper, the generalized shooting method and the harmonic balancing method to determine the periodic orbit, its period and the approximate analytic expression of the non-linear bearing-rotor system are presented. At first, by changing the time scale, the period of the periodic orbit of the non-linear system is drawn into the governing equation of the system explicitly. Then, the generalized shooting procedure is sought out. The increment value changed in the iteration procedure is selected by using the optimization method. The procedure involves determining the periodic orbit and its period of the system, and the stability of the periodic solution is determined by using Floquet stability theory. The validity of such method is verified by determining the periodic orbit and period of the forced van der Pol equation. Secondly, the periodic solution of the non-linear rotor-bearing system is expanded into Fourier series according to the character of the solution obtained by using the generalized shooting method. Then the approximate analytic expression of the periodic solution of the system is obtained by using the harmonic balancing method. Theoretically, the solution with any precision can be obtained by adding the number of the harmonics. At last, the periodic orbit, period and approximate analytic expressions of the periodic solution of the non-linear rotor-bearing system are provided.
Chaos in periodically forced Holling type II predator-prey system with impulsive perturbations
International Nuclear Information System (INIS)
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type II functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of prey. The impulsive perturbation is affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can very easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade, (5) non-unique dynamics
Chaos in periodically forced Holling type IV predator-prey system with impulsive perturbations
International Nuclear Information System (INIS)
The effect of periodic forcing and impulsive perturbations on predator-prey model with Holling type IV functional response is investigated. The periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. The impulsive perturbations are affected by introducing periodic constant impulsive immigration of predator. The dynamical behavior of the system is simulated and bifurcation diagrams are obtained for different parameters. The results show that periodic forcing and impulsive perturbation can easily give rise to complex dynamics, including (1) quasi-periodic oscillating, (2) period doubling cascade, (3) chaos, (4) period halfing cascade
Probabilistic analysis of reliability indexes of rector control system sub-system with periodic serviceability testing
International Nuclear Information System (INIS)
A reliability model of a system which includes a protected object and a safety system has been proposed. The model allows taking into consideration the sequence of the system elements failures resulting in the system failure, as well as periodic serviceability testing of the elements. The described procedure of asymptotic estimations obtaining the mean time to failure and the failure probability depending on time is based in the renewal theory and considerably more simple than traditionally used Markov and semi-Markov models. The model application for rector control system sub-system reliability analysis was demonstrated
Dynamical System Approach to a Coupled Dispersionless System: Localized and Periodic Traveling Waves
International Nuclear Information System (INIS)
We investigate the dynamical behavior of a coupled dispersionless system describing a current-conducting string with infinite length within a magnetic field. Thus, following a dynamical system approach, we unwrap typical miscellaneous traveling waves including localized and periodic ones. Studying the relative stabilities of such structures through their energy densities, we find that under some boundary conditions, localized waves moving in positive directions are more stable than periodic waves which in contrast stand for the most stable traveling waves in another boundary condition situation. (general)
Almost periodic solutions of distributed parameter biochemical systems with time delay and time varying input
Abdou K. Drame; Mangala R. Kothari; Peter R. Wolenski
In this article we study the existence of almost periodic solutions for distributed parameters biochemical system, with time delay when the input $S_{m in}$ is time dependent. This study is motivated by the input begin time dependent in many applications, and by the importance of almost periodically varying environments. Using the semigroup method, we prove that if the input is almost periodic then the system has an almost periodic solution.
Branching of periodic orbits in reversible hamiltonian systems
Buzzi, Claudio; Teixeira, Marco Antonio
This paper deals with the dynamics of time-reversible Hamiltonian vector fields with 2 and 3 degrees of freedom around an elliptic equilibrium point in presence of symplectic involutions. The main results discuss the existence of one-parameter families of reversible periodic solutions terminating at the equilibrium. The main techniques used are Birkhoff and Belitskii normal forms combined with the Liapunov-Schmidt reduction.
State of the glutathione system at different periods after irradiation
International Nuclear Information System (INIS)
The effect of the 3-fold irradiation on the glutatione system was studied. Activation of these system was shown to take place at early terms (1 hour) after irradiation, then it was exhausted that resulted in accumulation of lipid peroxidation products in blood. This phase changes in glutathione system could be correspond to certain stages of stress-syndrome. (author)
Bifurcations from one-parameter families of symmetric periodic orbits in reversible systems
International Nuclear Information System (INIS)
We study bifurcations from one-parameter families of symmetric periodic orbits in reversible systems and give simple criteria for subharmonic symmetric periodic orbits to be born from the one-parameter families. Our result is illustrated for a generalization of the Hķnon¢Heiles system. In particular, it is shown that there exist infinitely many families of symmetric periodic orbits bifurcating from a family of symmetric periodic orbits under a general condition. Numerical computations for these bifurcations and symmetric periodic orbits are also given. (paper)
Radiogenic and U-series isotopes in very low sedimentation rate sediments from Mendeleev Ridge (Arctic Ocean): sources, mineral carriers and stratigraphic implications
Hillaire-Marcel, C.; Darby, D.; Francois, R.; Helie, J.; Lamziouaq, R.; Not, C.; Polyak, L.; Preda, M.; Satte, Y. M.; Stevenson, R.
Sedimentological and geochemical properties, U-series isotopes, radiogenic isotopes and anthropogenic radionuclides contents were determined on two cores from the Mendeleev Ridge. Excesses in 210Pb over 226Ra activities are observed down to 1.25 cm from core-tops, due to shallow mixing by benthic organisms. Below, 210Pb-activity follows 226Ra-activity in turn controlled by parent 230Th-excess fluctuations in the sediment, except for some 226Ra-diffusion towards the water column from core-top and on both sides of 230Thxs peaks below. Thus, estimating 210Pb-excess requires precise knowledge of 226Ra-supported fraction, i.e., of 230Th- excess and Ra-diffusion. Both cores depict identical grain size, mineralogical, geochemical and isotopic distributions, despite bathymetric difference. This suggests negligible impact of bottom currents, limited scavenging of heavy metals in the lower water column, and a net export of particle reactive U-daughter isotopes (Th, Pa, Pb) produced from the overlying water column. Peaks in 230Thxs and 231Paxs (0-7cm, 17 cm and 30 cm sub-bottom) match high contents in clays and fine carbonates (primarily dolomite), and likely indicate interglacial/interstadial conditions and/or occurrence of turbidity events (e.g., during deglaciations). These peaks correspond to maximum illite supplies, minimum Sr-isotope ratios and epsilon-Nd values in the -10 to -12 range. Interlayered sediments, with high sand but low carbonate contents, minimum clay fluxes (low illite relative contents), minimum 230Th and 231Pa excesses, maximum Sr-isotope ratios, possibly indicate full glacial conditions and significantly reduced sedimentation rates.
Commissioning and periodic tests of the Esteya« electronic brachytherapy system
Niatsetski, Yury; Ouhib, Zoubir; Ballester, Facundo; Vijande, Javier; Perez-Calatayud, Jose
A new electronic brachytherapy unit from Elekta, called Esteya«, has recently been introduced to the market. As a part of the standards in radiation oncology, an acceptance testing and commissioning must be performed prior to treatment of the first patient. In addition, a quality assurance program should be implemented. A complete commissioning and periodic testing of the Esteya« device using the American Association of Physicists in Medicine (AAPM), Groupe Europķen de Curiethķrapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO) guidelines for linacs and brachytherapy units as well as our personal experience is described in this paper. In addition to the methodology, recommendations on equipment required for each test are provided, taking into consideration their availability and traceability of the detectors. Finally, tolerance levels for all the tests are provided, and a specific frequency for each test is suggested.
Use of Harmonic Inversion Techniques in the Periodic Orbit Quantization of Integrable Systems
Weibert, K; Wunner, G
Harmonic inversion has already been proven to be a powerful tool for the analysis of quantum spectra and the periodic orbit orbit quantization of chaotic systems. The harmonic inversion technique circumvents the convergence problems of the periodic orbit sum and the uncertainty principle of the usual Fourier analysis, thus yielding results of high resolution and high precision. Based on the close analogy between periodic orbit trace formulae for regular and chaotic systems the technique is generalized in this paper for the semiclassical quantization of integrable systems. Thus, harmonic inversion is shown to be a universal tool which can be applied to a wide range of physical systems. The method is further generalized in two directions: Firstly, the periodic orbit quantization will be extended to include higher order hbar corrections to the periodic orbit sum. Secondly, the use of cross-correlated periodic orbit sums allows us to significantly reduce the required number of orbits for semiclassical quantizatio...
Confrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observations
Morcos, A. B.
A simple formula, using the quantum numbers of solar system planets and some quantized extra-solar planets, to estimate the periods, is done. The quantum numbers, calculated by other authors, have been used to find the orbital periods of solar system planets and some extra-solar planets. Observed periods have been used to compare them with the estimated periods from the given formula. It is found that the given relation is applicable perfectly for the solar system planets. Some extra-solar p...
The direct approach to gravitation and electrostatics method for periodic systems
DEFF Research Database (Denmark)
Losilla, Sergio Alberto; Sundholm, D
The direct approach to gravitation and electrostatics (DAGE) algorithm is an accurate, efficient, and flexible method for calculating electrostatic potentials. In this paper, we show that the algorithm can be easily extended to consider systems with many different kinds of periodicities, such as crystal lattices, surfaces, or wires. The accuracy and performance are nearly the same for periodic and aperiodic systems. The electrostatic potential for semiperiodic systems, namely defects in crystal lattices, can be obtained by combining periodic and aperiodic calculations. The method has been applied to an ionic model system mimicking NaCl, and to a corresponding covalent model system.
The virial theorem and exact properties of density functionals for periodic systems
Mirhosseini, H.; Cangi, A.; Baldsiefen, T.; Sanna, A.; Proetto, C. R.; Gross, E.K.U.
In the framework of density functional theory, scaling and the virial theorem are essential tools for deriving exact properties of density functionals. Preexisting mathematical difficulties in deriving the virial theorem via scaling for periodic systems are resolved via a particular scaling technique. This methodology is employed to derive universal properties of the exchange-correlation energy functional for periodic systems.
Existence of periodic orbits in three-dimensional piecewise linear systems
Huan, Songmei; Yang, Xiao-Song
Based on the results about the invariant cones appeared in the literature this paper analyses the existence of periodic orbits in three-dimensional continuous piecewise linear homogeneous systems with two zones, and a necessary and sufficient condition for the existence of periodic orbits of such systems is given.
Regulatory strategy for effective application of periodic safety review system
International Nuclear Information System (INIS)
In less than 10 years, the first commercial pressurized water reactor (PWR) plant in Korea will reach its official design life. As part of safety activities, developed countries have already implemented periodic safety review (PSR) or equivalent programs to check and improve the safety of operating nuclear power plants (NPP) during their plant life. At the end of 1999, it was decided by the Korean Atomic Energy Safety Committee to adopt the PSR program and to apply it to Korean operating NPP. Since Kori Unit 1 started the review for the first tentative application of PSR as a model case in May 2000, it is now progressing well. Management of aging is one of the major factors to be considered in PSR and life extension of a nuclear plant. This paper is intended to introduce the regulatory aspect and strategy of Korean PSR. The background and scope of basic PSR guidelines are described, and a summary of technical criteria for aging management, which shows a regulatory direction for PSR, is also presented
Evaluation of electric power distribution systems: period 1984/89
International Nuclear Information System (INIS)
The historical evolution of electric power distribution systems in Brazil, during 1984 to 1989 is described, showing the consumer market with the physical expansion of Distribution Networks and the results of quality from the services made by the companies to their clients. (C.G.C.)
The Kondo effect in periodic narrow-band systems
Irkhin, V. Yu.; Zarubin, A. V.
The Kondo divergences owing to interaction of current carriers with local moments in highly correlated electron systems are considered within the Hubbard and s-d exchange models with infinitely strong on-site interaction, the many-electron Hubbard representation being used. The picture of density of states containing a peak at the Fermi level is obtained. Various forms of the self-consistent approximation are used. The problem of the violation of analytical properties of the...
A phase-lock-loop-based control system for suppressing periodic vibration in smart structural systems
Algrain, Marcelo; Hardt, Steve; Ehlers, Douglas
This paper presents a simple, effective and economical system capable of suppressing periodic vibration (external or self-induced) affecting a structure or payload. The approach used integrates piezoelectric materials/actuators, sensors and low-cost electronics in a novel way. The key innovation is the use of phase-lock loops (PLLs) and switch-capacitor filters (SCFs) for the on-line identification, tracking and control of periodic vibration. This method concentrates its control action at those frequencies where periodic vibration is detected. Among the advantages of this approach are the following: it is conceptually simple, easily expandable and modular; the controller does not rely on a model of the structure and it only needs some approximate notion of the frequency range where the periodic disturbances are expected to occur; it is robust and can be operated at high gain without loss of stability; it is not significantly affected by the presence of random vibration or sensor noise and it can be implemented with inexpensive electronics. The effectiveness of this new approach was experimentally evaluated using a test unit consisting of a simple structure, accelerometers and Terfenol-D actuators. The structure was excited by driving one of the actuators with sinusoidal and random signals. The resulting periodic disturbances were measured using the accelerometers. The acceleration signals were passed though a bank of PLLs and associated SCFs to detect the fundamental frequency and harmonics. This information was used to drive another actuator that rejected the original disturbances, and attenuation levels as high as 30 dB were achieved.
Solving periodic block tridiagonal systems using the Sherman-Morrison-Woodbury formula
International Nuclear Information System (INIS)
Many algorithms for solving the Navier-Stokes equations require the solution of periodic block tridiagonal systems of equations. By applying a splitting to the matrix representing this system of equations, it may first be reduced to a block tridiagonal matrix plus an outer product of two block vectors. The Sherman-Morrison-Woodbury formula is then applied. The algorithm thus reduces a periodic banded system to a non-periodic banded system with additional right-hand sides and is of higher efficiency than standard Thomas algorithm/LU decompositions
Period two implies chaos for a class of ODEs: a dynamical system approach
Pireddu, Marina
The aim of this note is to set in the field of dynamical systems a recent theorem by Obersnel and Omari about the presence of periodic solutions of all periods for a class of scalar time-periodic first order differential equations without uniqueness, provided a subharmonic solution (and thus, for instance, a solution of period two) does exist. Indeed, making use of the Bebutov flow, we try to clarify in what sense the term "chaos" has to be understood and which dynamical features can be inferred for the system under analysis.
Low energy theories describing topological properties of periodic systems
Budich, Jan Carl
We discuss the ostensible paradox between the abstract definition of physical observables as topological properties of the Brillouin zone (BZ) of a condensed matter system as a whole and their successful prediction by effective low energy theories the validity of which is limited to the closest vicinity of a high symmetry point in the BZ. We show that the control parameter of a topological phase transition can act as the deformation parameter of a homotopy transformation localizing the topological defect in an arbitrarily small neighbourhood of a single point in $k$-space. We illustrate this mechanism and its limitations with the help of experimentally relevant examples such as HgTe/CdTe quantum wells and bilayer graphene nanostructures.
Controlling chaos in low and high dimensional systems with periodic parametric perturbations
International Nuclear Information System (INIS)
The effect of applying a periodic perturbation to an accessible parameter of various chaotic systems is examined. Numerical results indicate that perturbation frequencies near the natural frequencies of the unstable periodic orbits of the chaotic systems can result in limit cycles for relatively small perturbations. Such perturbations can also control or significantly reduce the dimension of high-dimensional systems. Initial application to the control of fluctuations in a prototypical magnetic fusion plasma device will be reviewed
Stabilization of Periodic Solutions in a Thedered Satellite System by Damping Injection
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
A spacecraft with electrodynamic tether orbiting the Earth will be subject to a periodic forcing term induced by the variation of the magnetic field along the orbit. The periodic forcing term leads to a family of unstable periodic solutions for a tether carrying a constant current. This paper presents a control design for stabilizing these periodic solutions. The design consists of a control law for stabilising the open-loo equibrilibrium and a bias term which forces the system trajectory away from the equilibrium. The tether needs to be positioned away from open-loop equilibrium for the tether to affect the orbit parameters. An approximation of the periodic solutions of the closed loop system is found as a series expansion in the parameter plane spanned by the controller gain and the bias term. The stability of the solutions is investigated using linear Floquet analysis of the variational equation and the region of stable periodic solutions in the parameter plane is found.
Long-time behavior of periodically driven isolated interacting lattice systems
D'Alessio, Luca; Rigol, Marcos
We study the dynamics of isolated interacting spin chains that are periodically driven by sudden quenches. Using full exact diagonalization of finite chains, we show that these systems exhibit three distinct regimes. For short driving periods, the Floquet Hamiltonian is well approximated by the time-averaged Hamiltonian, while for long periods the evolution operator exhibits properties of random matrices of a Circular Ensemble (CE). In-between, there is a crossover regime. B...
Gradient Based Control and Synchronization of Lorenz System with Periodic Parametric Forcing
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Mohammad Ali Khan
Full Text Available Several important properties of chaos synchronization with gradientbased control of chaotic system with periodic parametric forcing remainstill unexplored. This paper investigates the behavior of the Lorenz systemto change from chaotic to periodic, parametric forcing also entrainsthe system output with the forcing frequency. Secondly synchronizationof two identically chaotic Lorenz systems are derived by linear feedbackcontrol and then discussed the gradient based control method for Lorenzsystem with periodic parametric forcing. Finally numerical simulationresults are presented to show the feasibility and effectiveness of the approach.
The effect of short recovery period investment on least-cost generation system expansion
International Nuclear Information System (INIS)
The effect of the short recovery period of private investment on least-cost generation system expansion is analysed, and a trade-off method for generation system expansion, which gives consideration to both the least-cost strategy and the short recovery period of private investment, is presented. First, the optimal mix of generation units under a standard recovery period for all units is established, and then the surcharge, due to the difference between the short recovery period and the standard recovery period, is calculated and shared between all units. The former is an optimization to make best use of natural resources, and the latter is a trade-off method to spread the surcharge throughout the system. (Author)
Stochastic long term modelling of a drainage system with estimation of return period uncertainty
DEFF Research Database (Denmark)
Thorndahl, Sžren
Long term prediction of maximum water levels and combined sewer overflow (CSO) in drainage systems are associated with large uncertainties. Especially on rainfall inputs, parameters, and assessment of return periods. This paper proposes a Monte Carlo based methodology for stochastic prediction of both maximum water levels as well as CSO volumes based on operations of the urban drainage model MOUSE (Lindberg and Joergensen 1986) in a single catchment case study. Results show quite a wide confidence interval of the model predictions especially on the large return periods. Traditionally, return periods of drainage system predictions are based on ranking, but this paper proposes a new methodology for the assessment of return periods. Based on statistics of characteristic rainfall parameters and correlation with drainage system predictions, it is possible to predict return periods more reliably, and with smaller confidence bands compared to the traditional methodology.
Self-similarities of periodic structures for a discrete model of a two-gene system
Energy Technology Data Exchange (ETDEWEB)
Souza, S.L.T. de, E-mail: email@example.com [Departamento de FĒsica e Matemßtica, Universidade Federal de SŃo JoŃo del-Rei, Ouro Branco, MG (Brazil); Lima, A.A. [Escola de Farmßcia, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Caldas, I.L. [Instituto de FĒsica, Universidade de SŃo Paulo, SŃo Paulo, SP (Brazil); Medrano-T, R.O. [Departamento de CiĻncias Exatas e da Terra, Universidade Federal de SŃo Paulo, Diadema, SP (Brazil); GuimarŃes-Filho, Z.O. [Aix-Marseille Univ., CNRS PIIM UMR6633, International Institute for Fusion Science, Marseille (France)
We report self-similar properties of periodic structures remarkably organized in the two-parameter space for a two-gene system, described by two-dimensional symmetric map. The map consists of difference equations derived from the chemical reactions for gene expression and regulation. We characterize the system by using Lyapunov exponents and isoperiodic diagrams identifying periodic windows, denominated Arnold tongues and shrimp-shaped structures. Period-adding sequences are observed for both periodic windows. We also identify Fibonacci-type series and Golden ratio for Arnold tongues, and period multiple-of-three windows for shrimps. -- Highlights: ? The existence of noticeable periodic windows has been reported recently for several nonlinear systems. ? The periodic window distributions appear highly organized in two-parameter space. ? We characterize self-similar properties of Arnold tongues and shrimps for a two-gene model. ? We determine the period of the Arnold tongues recognizing a Fibonacci-type sequence. ? We explore self-similar features of the shrimps identifying multiple period-three structures.
Thermomechanics of the joint-synovial fluid system under periodic and impulse actions
Kartashov, ╔. M.
The thermomechanical reaction of the joint-synovial fluid system to periodic and impulse actions has been investigated. The behavior of the body of the joint near the articular surface Ś resistance of the bone material of the joint to periodic mechanical actions Ś has been established. It has been shown that the most destructive actions for the joint are instantaneous impulse shock mechanical actions.
Periodic solutions for second-order Hamiltonian systems with the p-Laplacian
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Weigao Ge
Full Text Available In this paper, we investigate the periodic solutions of Hamiltonian system with the p-Laplacian. By using Mountain Pass Theorem the existence of at least one periodic solution is obtained, Furthermore, under suitable assumptions, we obtain the existence of infinitely many solutions via $Z_2$-symmetric version of the Mountain Pass Theorem.
Hopf-pitchfork bifurcation and periodic phenomena in nonlinear financial system with delay
International Nuclear Information System (INIS)
Highlights: ? We derive the unfolding of a financial system with Hopf-pitchfork bifurcation. ? We show the coexistence of a pair of stable small amplitudes periodic solutions. ? At the same time, also there is a pair of stable large amplitudes periodic solutions. ? Chaos can appear by period-doubling bifurcation far away from Hopf-pitchfork value. ? The study will be useful for interpreting economics phenomena in theory. - Abstract: In this paper, we identify the critical point for a Hopf-pitchfork bifurcation in a nonlinear financial system with delay, and derive the normal form up to third order with their unfolding in original system parameters near the bifurcation point by normal form method and center manifold theory. Furthermore, we analyze its local dynamical behaviors, and show the coexistence of a pair of stable periodic solutions. We also show that there coexist a pair of stable small-amplitude periodic solutions and a pair of stable large-amplitude periodic solutions for different initial values. Finally, we give the bifurcation diagram with numerical illustration, showing that the pair of stable small-amplitude periodic solutions can also exist in a large region of unfolding parameters, and the financial system with delay can exhibit chaos via period-doubling bifurcations as the unfolding parameter values are far away from the critical point of the Hopf-pitchfork bifurcation.
Pure-rotary periodic motions of a planar two-ball auto-balancer system
Lu, Chung-Jen; Tien, Meng-Hsuan
Ball-type automatic balancers have been widely used to suppress the unbalanced vibration of rotor systems. However, instead of reaching the desired perfect balancing position, where the balls of the automatic balancer are allocated properly so that the rotor is perfectly balanced, the system may settle into a pure-rotary periodic motion, in which all the balls stick together and keep rotating around the balancer. Because the associated large vibrations may deteriorate the performance of the rotor system, it is desirable to avoid the pure-rotary periodic motion. To this end, there is a need to understand the properties of pure-rotary periodic motions clearly. In this study, we used the modified incremental harmonic balance method to find pure-rotary periodic motions numerically. The existence and stable regions of the pure-rotary periodic motion in a two-parameter plane were identified. The effects of system parameters on the stable regions of the pure-rotary periodic motion were examined. By comparing the stable regions of the pure-rotary periodic motion with those of the perfect balancing position, the variation of the steady-state response with the rotational speed was investigated. We also conducted experiments to test the stability of the pure-rotary periodic motion under different conditions. The experimental results agree well with the numerical results.
Stochastic period-doubling bifurcation in biharmonic driven Duffing system with random parameter
International Nuclear Information System (INIS)
Stochastic period-doubling bifurcation is explored in a forced Duffing system with a bounded random parameter as an additional weak harmonic perturbation added to the system. Firstly, the biharmonic driven Duffing system with a random parameter is reduced to its equivalent deterministic one, and then the responses of the stochastic system can be obtained by available effective numerical methods. Finally, numerical simulations show that the phase of the additional weak harmonic perturbation has great influence on the stochastic period-doubling bifurcation in the biharmonic driven Duffing system. It is emphasized that, different from the deterministic biharmonic driven Duffing system, the intensity of random parameter in the Duffing system can also be taken as a bifurcation parameter, which can lead to the stochastic period-doubling bifurcations
Periodic solutions of nonlinear dynamical systems numerical computation, stability, bifurcation and transition to chaos
Reithmeier, Eduard
Limit cycles or, more general, periodic solutions of nonlinear dynamical systems occur in many different fields of application. Although, there is extensive literature on periodic solutions, in particular on existence theorems, the connection to physical and technical applications needs to be improved. The bifurcation behavior of periodic solutions by means of parameter variations plays an important role in transition to chaos, so numerical algorithms are necessary to compute periodic solutions and investigate their stability on a numerical basis. From the technical point of view, dynamical systems with discontinuities are of special interest. The discontinuities may occur with respect to the variables describing the configuration space manifold or/and with respect to the variables of the vector-field of the dynamical system. The multiple shooting method is employed in computing limit cycles numerically, and is modified for systems with discontinuities. The theory is supported by numerous examples, mainly fro...
Control of nonlinear systems using periodic parametric perturbations with application to a reversed field pinch
Energy Technology Data Exchange (ETDEWEB)
Mirus, K.A.
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses.
Control of nonlinear systems using periodic parametric perturbations with application to a reversed field pinch
International Nuclear Information System (INIS)
In this thesis, the possibility of controlling low- and high-dimensional chaotic systems by periodically driving an accessible system parameter is examined. This method has been carried out on several numerical systems and the MST Reversed Field Pinch. The numerical systems investigated include the logistic equation, the Lorenz equations, the Roessler equations, a coupled lattice of logistic equations, a coupled lattice of Lorenz equations, the Yoshida equations, which model tearing mode fluctuations in a plasma, and a neural net model for magnetic fluctuations on MST. This method was tested on the MST by sinusoidally driving a magnetic flux through the toroidal gap of the device. Numerically, periodic drives were found to be most effective at producing limit cycle behavior or significantly reducing the dimension of the system when the perturbation frequency was near natural frequencies of unstable periodic orbits embedded in the attractor of the unperturbed system. Several different unstable periodic orbits have been stabilized in this way for the low-dimensional numerical systems, sometimes with perturbation amplitudes that were less than 5% of the nominal value of the parameter being perturbed. In high-dimensional systems, limit cycle behavior and significant decreases in the system dimension were also achieved using perturbations with frequencies near the natural unstable periodic orbit frequencies. Results for the MST were not this encouraging, most likely because of an insufficient drive amplitude, the extremely high dimension of the plasma behavior, large amounts of noise, and a lack of stationarity in the transient plasma pulses
Condition for emergence of the Floquet-Gibbs state in periodically driven open systems
Shirai, Tatsuhiko; Mori, Takashi; Miyashita, Seiji
We study probability distribution of a steady state of a periodically driven system coupled to a thermal bath by using a quantum master equation in the weak coupling limit. It is proved that, even when the external field is strong, the probability distribution is independent of the detailed nature of the thermal bath under the following conditions: (i) the Hamiltonian of the relevant system is bounded and the period of the driving field is short, (ii) the Hamiltonians for th...
Linear time periodic modeling of power electronic devices for power system harmonic analysis and simulation
Ignatova, Vanya; Bacha, Seddik; Granjon, Pierre; RetiĶre, Nicolas
This paper presents an analytical frequency-domain method for harmonic estimation able to evaluate harmonics and interharmonics and to capture the coupling between frequencies. It is based on the linear time ¢ periodic system theory as a result of the periodic behaviour of the state variables in steady state operation. It consists of describing the considered system with a set of differential equations, presenting them in a matrix form in the frequency domain by decomposition of the convert...
Research on anti-disturbance property of HFETRC period monitoring system
International Nuclear Information System (INIS)
The anti-disturbance problem of the period monitoring system for test reactor critical assembly is mainly discussed and how to judge and search for the interference source using spotting experimental methods starting from the practical engineering without special equipment is introduced. So the electro-magnetic interference is removed. After finding out the reason, four measures are adopted to build up the anti-disturbance ability of the period monitoring system. (authors)
A general method for the existence of periodic solutions of differential systems in the plane
Fonda, Alessandro; Sfecci, Andrea
We propose a general method to prove the existence of periodic solutions for planar systems of ordinary differential equations, which can be used in many different circumstances. Applications are given to some nonresonant cases, even for systems with superlinear growth in some direction, or with a singularity. Systems "at resonance" are also considered, provided a Landesman-Lazer type of condition is assumed.
The period-ratio and mass-ratio correlation in extra-solar multiple planetary systems
Jiang, Ing-Guey; Yeh, Li-Chin; Hung, Wen-Liang
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period ratio and mass ratio of adjacent planet pairs are studied. The correlation between the period ratio and mass ratio is confirmed, with a correlation coefficient of 0.5303 with a 99 per cent confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.
The Period-Ratio and Mass-Ratio Correlation in Extra-Solar Multiple Planetary Systems
Jiang, Ing-Guey; Hung, Wen-Liang
Employing the data from orbital periods and masses of extra-solar planets in 166 multiple planetary systems, the period-ratio and mass-ratio of adjacent planet pairs are studied. The correlation between the period-ratio and mass-ratio is confirmed and found to have a correlation coefficient of 0.5303 with a 99% confidence interval (0.3807, 0.6528). A comparison with the distribution of synthetic samples from a Monte Carlo simulation reveals the imprint of planet-planet interactions on the formation of adjacent planet pairs in multiple planetary systems.
Periodic solutions for a two-species nonautonomous competition system with diffusion and impulses
International Nuclear Information System (INIS)
By re-estimating the upper bound of ?0?eui(t)dt (i=1,2), we generalize a result about the existence of a positive periodic solution for a two-species nonautonomous patchy competition system with time delay. Based on that system, we consider the impulsive harvesting and stocking, and establish a two-species nonautonomous competition Lotka-Volterra system with diffusion and impulsive effects. With the continuation theorem of coincidence degree theory, we obtain the existence of a positive periodic solution for such a system. At last, two examples are given to demonstrate our results
Stable 1 2 Resonant Periodic Orbits in Elliptic Three-Body Systems
Haghighipour, N; Varadi, F; Moore, W B; Haghighipour, Nader; Couetdic, Jocelyn; Varadi, Ferenc; Moore, William B.
The results of an extensive numerical study of the periodic orbits of planar, elliptic restricted three-body planetary systems consisting of a star, an inner massive planet and an outer mass-less body in the external 1:2 mean-motion resonance are presented. Using the method of differential continuation, the locations of the resonant periodic orbits of such systems are identified and through an extensive study of their phase-parameter space, it is found that the majority of the resonant periodic orbits are unstable. For certain values of the mass and the orbital eccentricity of the inner planet, however, stable periodic orbits can be found. The applicability of such studies to the 1:2 resonance of the extrasolar planetary system GJ876 is also discussed.
Periodic orbits and their stability in the R÷ssler prototype-4 system
International Nuclear Information System (INIS)
For the R÷ssler prototype-4 system x.=?y?z, y.=x, z.=?y(1?y)??z we prove the existence of periodic orbits and study their stability or instability. The main tool for proving these results is the averaging theory. Recently the existence of some of these periodic orbits were detected numerically. -- Highlights: ? We deal with the R÷ssler prototype-4 system x.=?y?z, y.=x, z.=?y(1?y)??z. ? It is one of the simplest autonomous differential equations exhibiting chaos. ? Recently some periodic orbits for this system has been detected numerically. ? We provide an analytical proof of these orbits and study their stability. ? Also we prove the existence of periodic orbits not detected numerically.
Near equilibrium distributions for beams with space charge in linear and nonlinear periodic focusing systems
Sonnad, Kiran G.; Cary, John R.
A procedure to obtain a near equilibrium phase space distribution function has been derived for beams with space charge effects in a generalized periodic focusing transport channel. The method utilizes the Lie transform perturbation theory to canonically transform to slowly oscillating phase space coordinates. The procedure results in transforming the periodic focusing system to a constant focusing one, where equilibrium distributions can be found. Transforming back to the original phase space coordinates yields an equilibrium distribution function corresponding to a constant focusing system along with perturbations resulting from the periodicity in the focusing. Examples used here include linear and nonlinear alternating gradient focusing systems. It is shown that the nonlinear focusing components can be chosen such that the system is close to integrability. The equilibrium distribution functions are numerically calculated, and their properties associated with the corresponding focusing system are discussed.
Periodic orbits in the doubly synchronous binary asteroid systems and their applications in space missions
Shang, Haibin; Wu, Xiaoyu; Cui, Pingyuan
This paper investigates the periodic motion of a particle in the doubly synchronous binary asteroid systems. Two typical doubly synchronous systems, 809 Lundia and 3169 Ostro, are discussed in detail. Under the Roche figure assumption, the two bodies of doubly synchronous system can be modeled as two triaxial ellipsoids. The Ivory's theorem is used to derive the gravitational potential of the system. Then, a global numerical method, which combines grid searching and differential correction, is developed for systematically searching periodic orbits in the doubly synchronous systems. A total of 30 and 28 families of periodic orbits around Lundia and Ostro are found, respectively. Furthermore, on the basis of the analysis of morphology, stabilities and invariant manifolds, the potential applications of these periodic orbit families are studied. Several quasi-circular orbit families with low instability index are found to be suitable for the observation of the two typical binary systems. The invariant manifolds of some periodic orbits near the equilibrium points can provide the fuel-free trajectories to achieve the ballistic landing to the surface of the asteroids and transfer between the binary asteroids.
Implementing Multi-Periodic Critical Systems: from Design to Code Generation
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Julien Forget
Full Text Available This article presents a complete scheme for the development of Critical Embedded Systems with Multiple Real-Time Constraints. The system is programmed with a language that extends the synchronous approach with high-level real-time primitives. It enables to assemble in a modular and hierarchical manner several locally mono-periodic synchronous systems into a globally multi-periodic synchronous system. It also allows to specify flow latency constraints. A program is translated into a set of real-time tasks. The generated code (C code can be executed on a simple real-time platform with a dynamic-priority scheduler (EDF. The compilation process (each algorithm of the process, not the compiler itself is formally proved correct, meaning that the generated code respects the real-time semantics of the original program (respect of periods, deadlines, release dates and precedences as well as its functional semantics (respect of variable consumption.
Existence and global attractivity of positive periodic solution for competition-predator system with variable delays
International Nuclear Information System (INIS)
In this paper, Lotka-Volterra competition-predator system with variable delays is considered. Some sufficient conditions ensuring the existence and global attractivity of periodic solution for this system are obtained by using coincidence degree theory and Lyapunov functional method. An example is also worked out to demonstrate the advantages of our results
Stabilizing periodic orbits of chaotic systems using fuzzy adaptive sliding mode control
International Nuclear Information System (INIS)
In this paper by using a combination of fuzzy identification and the sliding mode control a fuzzy adaptive sliding mode scheme is designed to stabilize the unstable periodic orbits of chaotic systems. The chaotic system is assumed to have an affine form x(n) = f(X) + g(X)u where f and g are unknown functions. Using only the input-output data obtained from the underlying dynamical system, two fuzzy systems are constructed for identification of f and g. Two distinct methods are utilized for fuzzy modeling, the least squares and the gradient descent techniques. Based on the estimated fuzzy models, an adaptive controller, which works through the sliding mode control, is designed to make the system track the desired unstable periodic orbits. The stability analysis of the overall closed loop system is presented in the paper and the effectiveness of the proposed adaptive scheme is numerically investigated. As a case of study, modified Duffing system is selected for applying the proposed method to stabilize its 2? and 4? periodic orbits. Simulation results show the high performance of the method for stabilizing the unstable periodic orbits of unknown chaotic systems
Global Behaviors and Optimal Harvesting of a Class of Impulsive Periodic Logistic Single-Species System with Continuous Periodic Control Strategy
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Xiang X
Full Text Available Global behaviors and optimal harvesting of a class of impulsive periodic logistic single-species system with continuous periodic control strategy is investigated. Four new sufficient conditions that guarantee the exponential stability of the impulsive evolution operator introduced by us are given. By virtue of exponential stability of the impulsive evolution operator, we present the existence, uniqueness and global asymptotical stability of periodic solutions. Further, the existence result of periodic optimal controls for a Bolza problem is given. At last, an academic example is given for demonstration.
Global Behaviors and Optimal Harvesting of a Class of Impulsive Periodic Logistic Single-Species System with Continuous Periodic Control Strategy
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Full Text Available Global behaviors and optimal harvesting of a class of impulsive periodic logistic single-species system with continuous periodic control strategy is investigated. Four new sufficient conditions that guarantee the exponential stability of the impulsive evolution operator introduced by us are given. By virtue of exponential stability of the impulsive evolution operator, we present the existence, uniqueness and global asymptotical stability of periodic solutions. Further, the existence result of periodic optimal controls for a Bolza problem is given. At last, an academic example is given for demonstration.
Long-time Behavior of Isolated Periodically Driven Interacting Lattice Systems
D'Alessio, Luca; Rigol, Marcos
We study the dynamics of isolated interacting spin chains that are periodically driven by sudden quenches. Using full exact diagonalization of finite chains, we show that these systems exhibit three distinct regimes. For short driving periods, the Floquet Hamiltonian is well approximated by the time-averaged Hamiltonian, while for long periods, the evolution operator exhibits properties of random matrices of a circular ensemble (CE). In between, there is a crossover regime. Based on a finite-size scaling analysis and analytic arguments, we argue that, for thermodynamically large systems and nonvanishing driving periods, the evolution operator always exhibits properties of the CE of random matrices. Consequently, the Floquet Hamiltonian is a nonlocal Hamiltonian with multispin interaction terms, and the driving leads to the equivalent of an infinite temperature state at long times. These results are connected to the breakdown of the Magnus expansion and are expected to hold beyond the specific lattice model considered.
Transitions between periodic orbits and control of chaos assisted by an external force in Hamiltonian systems
Scientific Electronic Library Online (English)
R.M., Angelo; K., Furuya; M.A.M. de, Aguiar.
Full Text Available We investigate the possibility of inducing transitions between periodic orbits in two-dimensional Hamiltonian systems by means of a time-localized external perturbation. We show that the amplitude of the perturbation can be approximately calculated in the limit of a delta-type force in terms of the [...] initial and final periodic orbits. For a specific Hamiltonian, we show several numerical examples where the external perturbation, varied from delta-type to gaussian, allows transitions between specifically chosen members of families of periodic orbits. The same mechanism is then applied to move aperiodic chaotic orbits into periodic ones, presenting a new way to control chaotic behavior in Hamiltonian systems.
Stability and Periodic Solution to Competitive Lotka-Volterra System with diffusion and Infinite Distributed Delay
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XU Tian-hua
Full Text Available A competitive Lotka-volterra systemwith diffusion and infinite distributed delays is investigated. It is shown that the globally asymptotically stable trivial solution, when r1(ai>=0,(i=1,2,the globally asymptotically stable semi-trivial periodic solution(r1(t,x,,and 0,r2(t,x when p1(a1=0,p1(a2<0 of the models byconstruction of a pair of upper and lower solution (u1,u2,(0,0of parabolic periodic system (aui(t,x/at-Aiui(t,x=ui(t,x[ai(t,x-bi(t,xui(t,x],and in the use of eigenvalue theory and comparison principle. A T-periodic series are established by using the monotone iteration technique. It was obtained that the systems have a pair of periodic positive solutions with respect to every nonnegative initial function.
Model reduction of nonlinear systems with external periodic excitations via construction of invariant manifolds
Gabale, Amit P.; Sinha, S. C.
A methodology for determining reduced order models of periodically excited nonlinear systems with constant as well as periodic coefficients is presented. The approach is based on the construction of an invariant manifold such that the projected dynamics is governed by a fewer number of ordinary differential equations. Due to the existence of external and parametric periodic excitations, however, the geometry of the manifold varies with time. As a result, the manifold is constructed in terms of temporal and dominant state variables. The governing partial differential equation (PDE) for the manifold is nonlinear and contains time-varying coefficients. An approximate technique to find solution of this PDE using a multivariable Taylor-Fourier series is suggested. It is shown that, in certain cases, it is possible to obtain various reducibility conditions in a closed form. The case of time-periodic systems is handled through the use of Lyapunov-Floquet (L-F) transformation. Application of the L-F transformation produces a dynamically equivalent system in which the linear part of the system is time-invariant; however, the nonlinear terms get multiplied by a truncated Fourier series containing multiple parametric excitation frequencies. This warrants some structural changes in the proposed manifold, but the solution procedure remains the same. Two examples; namely, a 2-dof mass-spring-damper system and an inverted pendulum with periodic loads, are used to illustrate applications of the technique for systems with constant and periodic coefficients, respectively. Results show that the dynamics of these 2-dof systems can be accurately approximated by equivalent 1-dof systems using the proposed methodology.
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Reliability modelling for wear out failure period of a single unit system
Arekar, Kirti; Ailawadi, Satish; Jain, Rinku
The present paper deals with two time-shifted density models for wear out failure period of a single unit system. The study, considered the time-shifted Gamma and Normal distributions. Wear out failures occur as a result of deterioration processes or mechanical wear and its probability of occurrence increases with time. A failure rate as a function of time deceases in an early failure period and it increases in wear out period. Failure rates for time shifted distributions and expression for m...
Instability conditions for some periodic BGK waves in the Vlasov-Poisson system
Pankavich, Stephen; Allen, Robert
A one-dimensional, collisionless plasma given by the Vlasov-Poisson system is considered and the stability properties of periodic steady state solutions known as Bernstein-Greene-Kruskal (BGK) waves are investigated. Sufficient conditions are determined under which BGK waves are linearly unstable under perturbations that share the same period as the equilibria. It is also shown that such solutions cannot support a monotonically decreasing particle distribution function.
Stochastic resonance in a periodic potential system under a constant force
International Nuclear Information System (INIS)
An overdamped particle moving in a periodic potential, and subject to a constant force and a stochastic force (i.e., ? = -sin(2??) + B + ?(t),?(t) is a white noise) is considered. The mobility of the particle, d/dt, is investigated. The stochastic resonance type of behaviour is revealed. The study of the SR problem can thus be extended to systems with periodic force. (author). 13 refs
Impact of capital gains taxation on the holding period of investments under different tax systems
Hegemann, Annika; Kunoth, Angela; Rupp, Kristina; Sureth, Caren
An investment that is characterized by exit flexibility requires both decisions on investment and holding period. As selling an investment often leads to tax-liable capital gains and capital gains crucially depend on the duration of an investment we investigate the impact of capital gains taxation on the holding period under three different tax systems. In our analytical investigation we examine whether there is an optimal exit time and if there is no optimal exit time, what would be an appro...
DMFT study of the local correlation effects in quasi-periodic system
Takemori, Nayuta; Koga, Akihisa
We study a two-dimensional Hubbard model on a Penrose lattice by means of the real-space dynamical mean-field theory. Calculating the renormalization factor and density of states at each site, we discuss local electron correlations on the quasi-periodic structure. It is found that the renormalized metallic state appears near the Mott transition in the Penrose lattice system. We also address a spatially-dependent renormalization characteristic of the quasi-periodic lattice.
Periodically time-varying memory static output feedback control design for discrete-time LTI systems
Lee, Dong Hwan; Joo, Young Hoon; Tak, Myung Hwan
This paper addresses the problem of static output feedback (SOF) stabilization for discrete-time LTI systems. We approach this problem using the recently developed periodically time-varying memory state-feedback controller (PTVMSFC) design scheme. A bilinear matrix inequality (BMI) condition which uses a pre-designed PTVMSFC is developed to design the periodically time-varying memory SOF controller (PTVMSOFC). The BMI condition can be solved by using BMI solvers. Alternative...
Phase-shift inversion in oscillator systems with periodically switching couplings
Lee, Sang Hoon; Lee, Sungmin; Son, Seung-woo; Holme, Petter
A system's response to external periodic changes can provide crucial information about its dynamical properties. We investigate the synchronization transition, an archetypical example of a dynamic phase transition, in the framework of such a temporal response. The Kuramoto model under periodically switching interactions has the same type of phase transition as the original mean-field model. Furthermore, we see that the signature of the synchronization transition appears in t...
Pointwise stability estimates for periodic traveling wave solutions of systems of viscous conservation laws
Jung, Soyeun
In the previous paper \\cite{J1}, we established pointwise bounds for the Green function of the linearized equation associated with spatially periodic traveling waves $\\bar u$ of a system of reaction diffusion equations, and also obtained pointwise nonlinear stability and behavior of $\\bar u$ under small perturbations. In this paper, using periodic resolvent kernels and the Bloch-decomposition, we establish pointwise bounds for the Green function of the linearized equation as...
International Nuclear Information System (INIS)
The Kepler mission is dramatically increasing the number of planets known in multi-planetary systems. Many adjacent planets have orbital period ratios near resonant values, with a tendency to be larger than required for exact first-order mean-motion resonances. This feature has been shown to be a natural outcome of orbital circularization of resonant planetary pairs due to star-planet tidal interactions. However, this feature holds in multi-planetary systems with periods longer than 10 days, in which tidal circularization is unlikely to provide efficient divergent evolution of the planets' orbits to explain these orbital period ratios. Gravitational interactions between planets and their parent protoplanetary disk may instead provide efficient divergent evolution. For a planet pair embedded in a disk, we show that interactions between a planet and the wake of its companion can reverse convergent migration and significantly increase the period ratio from a near-resonant value. Divergent evolution due to wake-planet interactions is particularly efficient when at least one of the planets opens a partial gap around its orbit. This mechanism could help account for the diversity of period ratios in Kepler's multiple systems from super-Earth to sub-Jovian planets with periods greater than about 10 days. Diversity is also expected for pairs of planets massive enough to merge their gap. The efficiency of wake-planet interactions is then much reduced, but convergent migration may stall with a variety of period ratios depending on the density structure in the common gap. This is illustrated for the Kepler-46 system, for which we reproduce the period ratio of Kepler-46b and c
The effect of volatile bubble growth rate on the periodic dynamics of shallow volcanic systems
Directory of Open Access Journals (Sweden)
I. L'Heureux
Full Text Available Many volcanic eruptions exhibit periodic behavior. For instance, periodic ground inflations and deflations in proximity to a volcano are the consequences of periodic overpressure variations in the magma conduit and periodic magma flow rate. The period varies from a few hours to many years, depending on the volcano parameters. On the other hand, volatile components exsolve from an ascending magma by forming bubbles. The strong dependence of the melt viscosity with the volatile concentration generates a positive feedback on the magma flow. We consider here the effect of the growth of volatile bubbles on the dynamics of a magmatic flow in a shallow volcanic system. Various expressions for the bubble growth rate are treated, thus generalizing previous work. In particular, a growth rate law derived from a recent many-bubble theory is considered. It is seen that, for a range of flow rate values at the base of the magma conduit, the system undergoes a Hopf bifurcation. Periodic solutions compatible with the observations are generated. This work shows that measurements of volcanic activity have the potential to test various bubble growth models in magmatic systems.
Light and period study of the eclipsing binary system TW Andromedae
Manzoori, D.
Photoelectric light curve (LC) solutions of the close binary system TW And were obtained using the PHOEBE program (version 0.31a). Absolute parameters of the stellar components were then determined, enabling us to discuss the structure and evolutionary status of TW And. The configuration of the system based on the LCs solutions indicates that the secondary component is slightly detached from its critical Roche surface. In addition, times of minima data (``O - C curve'') were analyzed. Apart from an almost parabolic variation of the general trend of the O - C data, indicative of a secular increase in the orbital period with a rate 0.032 s yr-1, which was attributed to a mass transfer with a rate of ? m2=-1.10ū10-10 M? yr-1. Additionally, a sinusoidal variation with a period of 52.75▒1.80 yr, modulating the orbital period, was found, which we attribute to a third body orbiting the system.
Busy Period Analysis of a Man-machine System Operating Subject To Different Physical Conditions
G. S. Mokaddis; M. L. Tawfek; S. A.M. Elhssia
This study deals with some characteristics of a single-unit of a man-machine system operating under different physical conditions. The failure, repair and change of physical conditions (good-poor) are stochastically independent random variables each having an arbitrary distribution. The system analysed by some Markov process technique. The busy period, expected number of visits by the repairman and the cost per unit time in a steady state of the system are obtained. Severa...
Numerical detection of unstable periodic orbits in continuous-time dynamical systems with chaotic behaviors
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Y. Saiki
Full Text Available An infinite number of unstable periodic orbits (UPOs are embedded in a chaotic system which models some complex phenomenon. Several algorithms which extract UPOs numerically from continuous-time chaotic systems have been proposed. In this article the damped Newton-Raphson-Mees algorithm is reviewed, and some important techniques and remarks concerning the practical numerical computations are exemplified by employing the Lorenz system.
Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor-Blade Systems
DEFF Research Database (Denmark)
Christensen, Rene Hardam; Santos, Ilmar
The demands for high efficiency machines initiate a demand for monitoring and active control of vibrations to improve machinery performance and to prolong machinery lifetime. Applying active control to reduce vibrations in flexible bladed rotor-systems imply that several difficulties have to be overcome. Among others it is necessary, that the control scheme is capable to cope with non-linear time-varying dynamical system behaviour. However, rotating at constant speed the mathematical model becomes periodic time-variant. In this framework the present paper gives a contribution to design procedures of active modal controllers. The main aim is to reduce vibrations in periodic time-varying structures. Special emphasis is given to vibration control of coupled bladed rotor systems. A state feedback modal control law is developed based on modal analysis in periodic time-varying structures. The first step in the procedure is a transformation of the model into a time-invariant modal form by applying the modal matrices, which are also periodic time-variant. Due to coupled rotor and blade motions complex vibration modes occur in the modal transformed state space model. This implies that the modal transformed model is reformulated using complex mode theory. Next, a linear constant gain controller for the reformulated system is designed by linear control technique. Finally, this constant gain controller is transformed to a time-periodic form by applying reverse modal transformation. The non-measurable states are estimated using a periodic time-varying state observer designed by a methodology similar to the controller design. Furthermore, the modal matrices are used to analyse the controllability of the system in order to determine optimal actuator placement in the system. For this the modal transform technique is a very effective tool. The control design methodology is applied to a coupled rotor-blade system to demonstrate the efficiency of such a procedure. A simulation model for the system is formulated and a time-periodic modal controller is designed using the described methodology. Simulation results are provided to demonstrate the applicability and effectiveness of the technique. The results obtained shows that the control design technique is capable to cope with the time periodicity of this class of systems.
Time-independent canonical perturbation theory for nearly multiple-periodic systems
International Nuclear Information System (INIS)
A modification of the classical canonical time-independent perturbation theory is presented for nearly multiple-periodic systems having the Hamiltonians of the form H = H0(Jsub(?)) + lambda H1(wsub(?),Jsub(?);qsub(k),psub(k)) + lambdasup(2)H2(wsub(?),Jsub(?);qsub(k),psub(k)) + ... where H1, H2, ... are periodic functions of angles wsub(?). The perturbation procedure is based on the averaging of the Hamilton-Jacobi equation over angles wsub(?). The existence of motion constants for all orders of the perturbation theory is shown for both non-degenerate and intrinsically degenerate systems. (author)
Pseudo-parity¢time symmetry in periodically high-frequency driven systems: perturbative analysis
International Nuclear Information System (INIS)
We investigate the periodically modulated two-level systems with balanced gain and loss by means of a multiple-scale asymptotic analysis. The pseudo-parity¢time symmetry (2013 Phys. Rev. Lett. 110 243902), which is often neglected in exact numerical simulations and totally lost in the commonly used high-frequency averaging approximation, has been fully understood in the framework of the second-order perturbative theory. Our work indicates that the multiple-scale asymptotic expansion method can be used to predict precisely some subtle and important dynamical behaviors in periodically driven systems. (paper)
Stable 1:2 Resonant Periodic Orbits in Elliptic Three-Body Systems
Haghighipour, Nader; Couetdic, Jocelyn; Varadi, Ferenc; Moore, William B.
The results of an extensive numerical study of the periodic orbits of planar, elliptic restricted three-body planetary systems consisting of a star, an inner massive planet and an outer mass-less body in the external 1:2 mean-motion resonance are presented. Using the method of differential continuation, the locations of the resonant periodic orbits of such systems are identified and through an extensive study of their phase-parameter space, it is found that the majority of t...
The period distribution of eclipsing and spectroscopic binary systems. Pt. 2
International Nuclear Information System (INIS)
A statistical analysis of period distribution for eclipsing and spectroscopic binary systems, based on the spectral types of the components, shows several common features between the two independent samples. The similarity is increased if we eliminate the geometrical selection effect on the eclipsing binaries sample by means of the method described in previous papers. The period distribution becomes broader (and probably non-unimodal) for advanced spectral types. We also performed an analysis of the mean separation of systems as a function of the spectral type. (orig.)
NSVS4484038, A contact binary system at the short-period cutoff
International Nuclear Information System (INIS)
We present a photometric study of the short-period eclipsing binary NSVS4484038. Time-series CCD photometry of the star in the B and V band was carried out. An orbital period of 0.218551 days was determined for the eclipsing binary and a revised linear ephemeris was given. The first photometric solution of the binary system was detected through light-curve synthesis using the Wilson-Devinney method. It reveals an overcontact configuration for the system with a filling-out factor of about 10%. The mass ratio was determined to be 2.74 with an inclination of 72.░1. The less massive secondary component is found to have a higher surface temperature than the primary by about 90 K, indicating that NSVS4484038 could be a contact system of W subtype. The star is then identified to be a new member of W UMa systems at the short-period cutoff. Comparisons with known contact binaries at the short-period cutoff, the properties, and the evolutionary status of the binary system are discussed.
Control of stochastic resonance in bistable systems by using periodic signals
International Nuclear Information System (INIS)
According to the characteristic structure of double wells in bistable systems, this paper analyses stochastic fluctuations in the single potential well and probability transitions between the two potential wells and proposes a method of controlling stochastic resonance by using a periodic signal. Results of theoretical analysis and numerical simulation show that the phenomenon of stochastic resonance happens when the time scales of the periodic signal and the noise-induced probability transitions between the two potential wells achieve stochastic synchronization. By adding a bistable system with a controllable periodic signal, fluctuations in the single potential well can be effectively controlled, thus affecting the probability transitions between the two potential wells. In this way, an effective control can be achieved which allows one to either enhance or realize stochastic resonance
Multi-Period Optimization for Voltage Control System in Transmission Grids
DEFF Research Database (Denmark)
Qin, Nan; Chen, Si
Automatic Voltage Control (AVC) systems maintain the voltage in an acceptable range and minimize the power loss of the grid by coordinately regulating the controllable components. Switchable shunts and tap-able transformers are expected to be operated as few times as possible. This paper proposes a two-level, multi-period optimal reactive power flow approach. In the upper level, the real-time measurements and short-term forecasts are used as the inputs of the multi-period optimization for one hour with 15 minutes intervals, to minimize the operational cost, subjected to a certain constraints. In the lower level, the optimization is focused on the correction of the voltage violations every single minute based on data from the measurements and state estimation. The presented case study shows that the multi-period optimization in the upper level of AVC system can reduce adjustment times of the discrete components for saving the total operational cost.
Can The Periods of Some Extra-Solar Planetary Systems be Quantized?
El Fady Morcos, Abd
A simple formula was derived before by Morcos (2013 ), to relate the quantum numbers of planetary systems and their periods. This formula is applicable perfectly for the solar system planets, and some extra-solar planets , of stars of approximately the same masses like the Sun. This formula has been used to estimate the periods of some extra-solar planet of known quantum numbers. The used quantum numbers were calculated previously by other authors. A comparison between the observed and estimated periods, from the given formula has been done. The differences between the observed and calculated periods for the extra-solar systems have been calculated and tabulated. It is found that there is an error of the range of 10% The same formula has been also used to find the quantum numbers, of some known periods, exo-planet. Keywords: Quantization; Periods; Extra-Planetary; Extra-Solar Planet REFERENCES [1] Agnese, A. G. and Festa, R. ōDiscretization on the Cosmic Scale Inspirred from the Old Quantum Mechanics,ö 1998. http://arxiv.org/abs/astro-ph/9807186 [2] Agnese, A. G. and Festa, R. ōDiscretizing ups-Andro- medae Planetary System,ö 1999. http://arxiv.org/abs/astro-ph/9910534. [3] Barnothy, J. M. ōThe Stability of the Solar Systemand of Small Stellar Systems,ö Proceedings of the IAU Sympo-sium 62, Warsaw, 5-8 September 1973, pp. 23-31. [4] Morcos, A.B. , ōConfrontation between Quantized Periods of Some Extra-Solar Planetary Systems and Observationsö, International Journal of Astronomy and Astrophysics, 2013, 3, 28-32. [5] Nottale, L. ōFractal Space-Time and Microphysics, To-wards a Theory of Scale Relativity,ö World Scientific, London, 1994. [6] Nottale , L., ōScale-Relativity and Quantization of Extra- Solar Planetary Systems,ö Astronomy & Astrophysics, Vol. 315, 1996, pp. L9-L12 [7] Nottale, L., Schumacher, G. and Gay, J. ōScale-Relativity and Quantization of the Solar Systems,ö Astronomy & Astrophysics letters, Vol. 322, 1997, pp. 1018-10 [8]Nottale, L. ōScale-Relativity and Quantization of Exo- planet Orbital Semi-Major Axes,ö Astronomy & Astro- physics, Vol. 361, 2000, pp. 379-387.
The periodically pulsed mode of operation of magnet systems in particle accelerators
International Nuclear Information System (INIS)
Since in many applications in particle accelerator technology the beam duty factor, defined by the ratio of beam pulse length to the pulse to pulse period, is very small- typically in the order of 10-3 to 10-9 - it is interesting to operate the beam optical magnetic system in the periodically pulsed mode as well. Thus, by reducing the average Ohmic losses, it is possible to save energy and material. The pulsed mode of operation of magnet systems is especially adapted to those of linear accelerators and their beam transport systems, since linear accelerators are exclusively operated in this mode. But it is equally suitable for transport systems between cyclic accelerators and large storage rings as they are under development at present. (orig./WL)
Component-wise positivity of solutions to periodic boundary problem for linear functional differential system.
Czech Academy of Sciences Publication Activity Database
Domoshnitsky, A.; Hakl, Robert; Ŗremr, Ji?Ē
Ro?. 112, May 22 (2012), s. 1-23. ISSN 1025-5834 Institutional support: RVO:67985840 Keywords : periodic problem * linear functional differential system * non-negative solution Subject RIV: BA - General Mathematics Impact factor: 0.879, year: 2010 http://www.journalofinequalitiesandapplications.com/content/2012/1/112
Periodic dynamics of delayed Lotka¢Volterra competition systems with discontinuous harvesting policies via differential inclusions
International Nuclear Information System (INIS)
Highlights: Ģ A more practical form of harvesting management policy (DHP) has been proposed. Ģ We analyze the periodic dynamics of a class of discontinuous and delayed Lotka¢Volterra competition systems. Ģ We present a new method to obtain the existence of positive periodic solutions via differential inclusions. Ģ The global convergence in measure of harvesting solution is discussed. -- Abstract: This paper considers a general class of delayed Lotka¢Volterra competition systems where the harvesting policies are modeled by discontinuous functions or by non-Lipschitz functions. By means of differential inclusions theory, cone expansion and compression fixed point theorem of multi-valued maps and nonsmooth analysis theory with generalized Lyapunov approach, a series of useful criteria on existence, uniqueness and global asymptotic stability of the positive periodic solution is established for the delayed Lotka¢Volterra competition systems with discontinuous right-hand sides. Moreover, the global convergence in measure of harvesting solution is discussed. Our results improve and extend previous works on periodic dynamics of delayed Lotka¢Volterra competition systems with not only continuous or even Lipschitz continuous but also discontinuous harvesting functions. Finally, we give some corollaries and numerical examples to show the applicability and effectiveness of the proposed criteria
Four positive periodic solutions of a discrete time Lotka-Volterra competitive system with harvesting terms
Directory of Open Access Journals (Sweden)
Xinggui Liu
Full Text Available In this paper, by using Mawhin's continuation theorem of coincidence degree theory, we establish the existence of at least four positive periodic solutions for a discrete time Lotka-Volterra competitive system with harvesting terms. An example is given to illustrate the effectiveness of our results.
Global Clock, Physical Time Order and Pending Period Analysis in Multiprocessor Systems
Chen, Yunji; Hu, Weiwu
In multiprocessor systems, various problems are treated with Lamport's logical clock and the resultant logical time orders between operations. However, one often needs to face the high complexities caused by the lack of logical time order information in practice. In this paper, we utilize the \\emph{global clock} to infuse the so-called \\emph{pending period} to each operation in a multiprocessor system, where the pending period is a time interval that contains the performed time of the operation. Further, we define the \\emph{physical time order} for any two operations with disjoint pending periods. The physical time order is obeyed by any real execution in multiprocessor systems due to that it is part of the truly happened operation orders restricted by global clock, and it is then proven to be independent and consistent with traditional logical time orders. The above novel yet fundamental concepts enables new effective approaches for analyzing multiprocessor systems, which are named \\emph{pending period analy...
Electronic spectra of one-dimensional nano-quasi-periodic systems under bias
Pķrez-Maldonado, M. T.; Monsivais, G.; Velasco, V.; RodrĒguez-Ramos, R.; Stern, C.
We investigate the properties of the energy spectra of quantum one-dimensional nano-quasi-crystals in the presence of external electric fields. These systems are modelled by means of finite sequences, ordered according to a Fibonacci rule which constituted of two blocks A (constant potentials of different heights defined on finite intervals) and B (delta potentials of different intensities). We use the electric field ability of producing Stark ladders in periodic systems to obtain well separated energy levels and to study the evolution of these levels when disorder is introduced. We show that this effect also allows us to predict the approximate position of the levels in the disordered system, in spite of its chaotic appearance at first view. We show, against the usual belief, that the nth Stark ladder in general is not formed exclusively from the levels of the nth band. The disorder is introduced in two different ways: by changing the distribution of the blocks or by changing the values of the delta potential intensities. In both cases we start from electrified periodic structures which are gradually perturbed to obtain electrified quasi-periodic structures. We show that the use of Fibonacci sequences as a particular case is not crucial and one can use the electric field to analyze any other type of quasi-periodic systems.
A New Method for Studying the Periodic System Based on a Kohonen Neural Network
Chen, David Zhekai
A new method for studying the periodic system is described based on the combination of a Kohonen neural network and a set of chemical and physical properties. The classification results are directly shown in a two-dimensional map and easy to interpret. This is one of the major advantages of this approach over other methods reported in theģ
Formation of nonlinear holographic images in a system of periodically located nonlinear mediums
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Belkov S.A.
Full Text Available The formation of nonlinear holographic images in a system of periodically located nonlinear mediums is studied. Analytical expressions which describe the magnitudes and locations of intensity maximums depending on the corresponding image number are derived. Comparison with numerical calculation results is presented.
Periodic solutions of the N-vortex Hamiltonian system in planar domains
Bartsch, Thomas; Dai, Qianhui
We investigate the existence of collision-free nonconstant periodic solutions of the $N$-vortex problem in domains $\\Omega\\subset\\mathbb{C}$. These are solutions $z(t)=(z_1(t),\\dots,z_N(t))$ of the first order Hamiltonian system \\[ \\dot{z}_k(t)=-i\
Periodic solutions of o.d.e. systems with a lipchitz non linearity
Rousselet, Bernard
In this report, we address differential systems with Lipschitz non linearities; this study is motivated by the subject of vibrations of structures with unilateral springs or non linear stress-strain law close to the linear case. We consider existence and solution with fixed point methods; this method is constructive and provides a numerical algorithm which is under study. We describe the method for a static case example and we address periodic solutions of differential systems arising in the vibration of structures.
Periodic forced vibration of unsymmetrical piecewise-linear systems by incremental harmonic balance method
Wong, C. W.; Zhang, W. S.; Lau, S. L.
A single-degree-of-freedom non-linear system subjected to periodic excitation is considered. The non-linearity is in the restoring force and is represented by unsymmetrical piecewise-linear stiffness. The steady state response are analysed by an extended incremental harmonic balance (IHB) method. All possible subharmonic, harmonic and superharmonic resonances and bifurcations are sought. The results reveal some interesting details of responses of unsymmetrical piecewise-linear systems. Comparisons with available published findings are also made.
The critical period of reservoir systems considering performance indices on Malaysia rivers
Issa Saket Oskoui; Rozi Abdullah; Majid Montaseri
The behavior of reservoir systems can be investigated using Critical Period (CP) which determines the aggregation level of the data (monthly or annual) that are required to be utilized in the reservoir analysis. Currently there are a number of methods that could approximate the behavior of reservoir systems, however the efficiency of these approaches have not been studied and verified for the Malaysia Rivers. In this study two different hypothetical reservoirs on Malaysia Rivers are selected...
Two-Well System under Large Amplitude Periodic Forcing: Stochastic Synchronization, Stochastic Resonance and Stability
Mahato, Mangal C.; Jayannavar, A. M.
We study the residence time distributions and explore the possibility of observing stochastic resonance and synchonization of passages in a two-well system driven by a periodic forcing of amplitude larger than a marginal value beyond which one of the two wells become unstable and diasppear. We define and calculate hysteresis loop in the system, the area of which measures the degree of synchronization between the residence time statistics and the input signal, as a function o...
Orbital periods and Accretion disc structure of four AM CVn systems
Kupfer, T; Levitan, D; Steeghs, D; Marsh, T R; Rutten, R G M; Nelemans, G
Phase-resolved spectroscopy of four AM CVn systems obtained with the William Herschel Telescope and the Gran Telescopio de Canarias (GTC) is presented. SDSS\\,J120841.96+355025.2 was found to have an orbital period of 52.96$\\pm$0.40\\,min and shows the presence of a second bright spot in the accretion disc. The average spectrum contains strong Mg\\,{\\sc i} and Si\\,{\\sc i/ii} absorption lines most likely originating in the atmosphere of the accreting white dwarf. SDSS\\,J012940.05+384210.4 has an orbital period of 37.555$\\pm$0.003 min. The average spectrum shows the Stark broadened absorption lines of the DB white dwarf accretor. The orbital period is close to the previously reported superhump period of 37.9\\,min. Combined, this results in a period excess $\\epsilon$=0.0092$\\pm$0.0054 and a mass ratio $q=0.031\\pm$0.018. SDSS\\,J164228.06+193410.0 displays an orbital period of 54.20$\\pm$1.60\\,min with an alias at 56.35\\,min. The average spectrum also shows strong Mg\\,{\\sc i} absorption lines, similar to SDSS\\,J120841...
Magnus' expansion for time-periodic systems: Parameter-dependent approximations
Butcher, Eric A.; Sari, Ma'en; Bueler, Ed; Carlson, Tim
Magnus' expansion solves the nonlinear Hausdorff equation associated with a linear time-varying system of ordinary differential equations by forming the matrix exponential of a series of integrated commutators of the matrix-valued coefficient. Instead of expanding the fundamental solution itself, that is, the logarithm is expanded. Within some finite interval in the time variable, such an expansion converges faster than direct methods like Picard iteration and it preserves symmetries of the ODE system, if present. For time-periodic systems, Magnus expansion, in some cases, allows one to symbolically approximate the logarithm of the Floquet transition matrix (monodromy matrix) in terms of parameters. Although it has been successfully used as a numerical tool, this use of the Magnus expansion is new. Here we use a version of Magnus' expansion due to Iserles [Iserles A. Expansions that grow on trees. Not Am Math Soc 2002;49:430-40], who reordered the terms of Magnus' expansion for more efficient computation. Though much about the convergence of the Magnus expansion is not known, we explore the convergence of the expansion and apply known convergence estimates. We discuss the possible benefits to using it for time-periodic systems, and we demonstrate the expansion on several examples of periodic systems through the use of a computer algebra system, showing how the convergence depends on parameters.
IEEE standard criteria for the periodic testing of nuclear power generating station safety systems
International Nuclear Information System (INIS)
This standard provides criteria and requirements for the development of periodic testing programs for protection and power systems in commercial nuclear power generating stations. Development of these criteria and requirements is based on the prerequisite that the protection and power systems are testable and on the following: (1) Station protection systems and Class 1E power systems must, during the life of the station, be repeatedly tested to assess the operational availability of the systems. (2) Development and application of testing procedures and equipment must be consistent with safety system criteria IEEE Std 603-1977, protection system criteria IEEE Std 279-1971, and Class 1E power system criteria IEEE Std 308-1974. (3) Procedures for verification and documentation of failures should be such that reliability confidence levels are enhanced. The Institute of Electrical and Electronics Engineers has developed these proposed criteria to provide guidance in the development of the procedures and equipment for, and documentation of, periodic testing of nuclear power generating station protection and power systems. Each applicant for a construction permit or an operating license for a nuclear facility is required to develop these items to comply with the Atomic Energy Commission's Code of Federal Regulations, Part 50
Investigation of unstable periodic space-time states in distributed active system with supercritical current
International Nuclear Information System (INIS)
The set of the unstable periodic space-time states, characterizing the chaotic space-time dynamics of the electron beam with the supercritical current in the Pierce diode is discussed. The Lyapunov indicators of the revealed instable space-time states of the chaotic dynamics of the distributed self-excited system are calculated. It is shown that change in the set of the unstable periodic states in dependence on the Pierce parameter is determined by change in the various orbits stability, which is demonstrated by the values of senior Lyapunov unstable state index
Anomalous edge states and the bulk-edge correspondence for periodically-driven two dimensional systems
DEFF Research Database (Denmark)
Rudner, Mark Spencer; Lindner, Netanel
Recently, several authors have investigated topological phenomena in periodically driven systems of noninteracting particles. These phenomena are identified through analogies between the Floquet spectra of driven systems and the band structures of static Hamiltonians. Intriguingly, these works have revealed phenomena that cannot be characterized by analogy to the topological classification framework for static systems. In particular, in driven systems in two dimensions (2D), robust chiral edge states can appear even though the Chern numbers of all the bulk Floquet bands are zero. Here, we elucidate the crucial distinctions between static and driven 2D systems, and construct a new topological invariant that yields the correct edge-state structure in the driven case. We provide formulations in both the time and frequency domains, which afford additional insight into the origins of the ōanomalousö spectra that arise in driven systems. Possibilities for realizing these phenomena in solid-state and cold-atomic systems are discussed.
International Nuclear Information System (INIS)
Many Kepler multiplanet systems have planet pairs near low-order, mean-motion resonances. In addition, many Kepler multiplanet systems have planets with orbital periods less than a few days. With the exception of Kepler-42, however, there are no examples of systems with both short orbital periods and nearby companion planets while our statistical analysis predicts ?17 such pairs. For orbital periods of the inner planet that are less than three days, the minimum period ratio of adjacent planet pairs follows the rough constraint P?P2/P1?>2.3 (P1/day)-2/3. This absence is not due to a lack of planets with short orbital periods. We also show a statistically significant excess of small, single-candidate systems with orbital periods below three days over the number of multiple candidate systems with similar periodsŚperhaps a small-planet counterpart to the hot Jupiters
Periodic Solution of Second-Order Hamiltonian Systems with a Change Sign Potential on Time Scales
Directory of Open Access Journals (Sweden)
Wan-Tong Li
Full Text Available This paper is concerned with the second-order Hamiltonian system on time scales 𝕋 of the form u??(?(t+?b(t|u(t|??2u(t+?»H(t,u(t=0,??-a.e. t?[0,T]𝕋?, u(0?u(T=u?(?(0?u?(?(T=0, where 0,T?𝕋. By using the minimax methods in critical theory, an existence theorem of periodic solution for the above system is established. As an application, an example is given to illustrate the result. This is probably the first time the existence of periodic solutions for second-order Hamiltonian system on time scales has been studied by critical theory.
Periodic orbits and nonintegrability of generalized classical Yang-Mills Hamiltonian systems
International Nuclear Information System (INIS)
The averaging theory of first order is applied to study a generalized Yang-Mills system with two parameters. Two main results are proved. First, we provide sufficient conditions on the two parameters of the generalized system to guarantee the existence of continuous families of isolated periodic orbits parameterized by the energy, and these families are given up to first order in a small parameter. Second, we prove that for the nonintegrable classical Yang-Mills Hamiltonian systems, in the sense of Liouville-Arnold, which have the isolated periodic orbits found with averaging theory, cannot exist in any second first integral of class C1. This is important because most of the results about integrability deals with analytic or meromorphic integrals of motion.
Multistability and stable asynchronous periodic oscillations in a multiple-delayed neural system
Campbell, S. A.; Ncube, I.; Wu, J.
We consider a network of three identical neurons with multiple discrete signal transmission delays. The model for such a network is a system of nonlinear delay differential equations. After some consideration of the absolute synchronization of the system and the global attractivity of the zero solution, we present a detailed discussion about the boundaries of the stability region of the trivial solution. This allows us to determine the possible codimension one bifurcations which occur in the system. In particular, we show the existence of standard Hopf bifurcations giving rise to synchronized periodic solutions and of D3 equivariant Hopf bifurcations giving rise to three types of periodic solutions: phase-locked, mirror-reflecting, and standing waves. Hopf-Hopf and Hopf-steady state bifurcations interactions are shown to exist and give rise to coexistence of stable synchronized and desynchronized solutions. Perturbation techniques coupled with the Floquet theory are used to determine the stability of the phase-locked oscillations.
An electro-mechanical periodic system with piezoelectric transducers and coupled circuitry: dynamic analysis and applications
Lu, Y.; Tang, J.
In this paper, we integrate piezoelectric transducers and coupled circuitry, which themselves form an electrical periodic system, onto a mechanical structure to form an electro-mechanical periodic system. The overall dynamics of the electro-mechanical system can thus be altered by tuning the electrical parameters. A transfer-matrix-based modeling technique is adopted in the dynamic analysis, where each element is represented by two state vectors at its both ends with a transfer matrix relating them. As the transfer matrix has the advantage on describing harmonic motions within the element, the global analysis can be facilitated given the repetitive nature of periodic systems. Numerical simulations are conducted to demonstrate the characteristics of wave propagation and attenuation in terms of propagation constants. Effects of each tunable parameter are also discussed through detailed parametric analysis. The proposed system can be tailored to various engineering needs. One example is adaptive vibration isolation with tunable effective frequency range. Another example is vibration energy harvesting through the piezoelectric transducers and circuitry.
Effects of time delay on stochastic resonance of a periodically driven linear system with multiplicative and periodically modulated additive white noises
International Nuclear Information System (INIS)
Stochastic resonance (SR) of a periodically driven time-delayed linear system with multiplicative white noise and periodically modulated additive white noise is investigated. In the condition of small delay time, an approximate analytical expression of output signal-to-noise ratio (SNR) is obtained. The analytical results indicate that (1) there exists a resonance peak in the curve for SNR versus time delay; (2) the time delay will suspend the SR dramatically for SNR versus other parameters of the system, such as noise intensity, correlation intensity, and signal frequency, once a certain value is reached, the SR phenomenon disappears. (general)
Ultrashort-period MS eclipsing systems. New observations and light curve solutions of six NSVS binaries
Dimitrov, Dinko
We carried out photometric and low-resolution spectral observations of six eclipsing ultrashort-period binaries with MS components. The light curve solutions of the Rozhen observations show that all targets are overcontact systems. We found well-defined empirical relation "period -- semi-major axis" for the short-period binaries and used it for estimation of the global parameters of the targets. Our results revealed that NSVS 925605 is quite interesting target: (a) it is one of a few contact binaries with M components; (b) it exhibits high activity (emission in H$\\alpha$ line, X-ray emission, large cool spots, non-Planck energy distribution); (c) its components differ in temperature by 700 K. All appearances of high magnetic activity and huge fillout factor (0.7) of NSVS 925605 might be assumed as a precursor of the predicted merging of close magnetic binaries. Another unusual binary is NSVS 2700153 which reveals considerable long-term variability.
Lifetime and reliability estimation of repairable redundant system subject to periodic alternation
International Nuclear Information System (INIS)
Lifetime distribution and reliability are analyzed for redundant systems consisting of units that alternate between operating and standby states periodically to inspect and detect failures of standby units. It is assumed that when a unit fails, a minimal repair with negligible repair time is performed. A cumulative exposure model is used to describe the failure time distribution. The method of maximum likelihood is used to estimate the parameters, and specific formulas for Weibull model are obtained. A simulation model is then developed to assess the system reliability based on the estimated lifetime distribution and the method is applied to a high pressure pump system
Dynamic behavior of dissymmetric rotor bearings modelled with a periodic coefficient large system
Guilhen, P. M.; Berthier, P.; Ferraris, G.; Lalanne, M.
The instability and unbalance response of dissymmetric rotor-bearing systems containing periodic coefficients when modeling produces matrices with a large number of degrees of freedom are discussed. It is important to solve the equations and then predict the dynamic behavior of the system. This can be done knowing the instability areas and the unbalance response in the stable areas. One deals here with a large number of equations and a reduction of the number of degrees of freedom of the system is achieved through a pseudo modal method. This method is shown to give satisfactory results.
Methods for estimation of radioactive iodine localization in post-accidental period using sprinkler systems
International Nuclear Information System (INIS)
A technique for estimation of radioactive iodine localization in NPP room air in post-accidental period using sprinkler systems is described. Analysis for radioactive iodine by means of sprinkler systems is performed for I2 as a representative of the group of inorganic compounds and CH3I as a representative of the group of organic compounds. The calculations show that the elimination coefficient for aerosol and elementary components changes slightly during the sprinkler system operation while for the organic component CH3I it decreases two times, at that the largest drop is observed during the first hour when temperature decreases to 60 deg
On the critical periods of Li├ā┬®nard systems with cubic restoring forces
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Zhengdong Du
Full Text Available We study local bifurcations of critical periods in the neighborhood of a nondegenerate center of a Li├ā┬®nard system of the form x├ŗ┬Ö=├ó┬ł┬Æy+F(x, y├ŗ┬Ö=g(x, where F(x and g(x are polynomials such that deg(g(x├ó┬ē┬ż3, g(0=0, and g├ó┬Ć┬▓(0=1, F(0=F├ó┬Ć┬▓(0=0 and the system always has a center at (0,0. The set of coefficients of F(x and g(x is split into two strata denoted by SI and SII and (0,0 is called weak center of type I and type II, respectively. By using a similar method implemented in previous works which is based on the analysis of the coefficients of the Taylor series of the period function, we show that for a weak center of type I, at most [(1/2deg(F(x]├ó┬ł┬Æ1 local critical periods can bifurcate and the maximum number can be reached. For a weak center of type II, the maximum number of local critical periods that can bifurcate is at least [(1/4deg(F(x].
Reverse resonance in stock prices of financial system with periodic information.
Li, Jiang-Cheng; Mei, Dong-Cheng
We investigate the stochastic resonance of the stock prices in a finance system with the Heston model. The extrinsic and intrinsic periodic information are introduced into the stochastic differential equations of the Heston model for stock price by focusing on the signal power amplification (SPA). We find that for both cases of extrinsic and intrinsic periodic information a phenomenon of reverse resonance emerges in the behaviors of SPA as a function of the system and external driving parameters. Moreover, in both cases, a phenomenon of double reverse resonance is observed in the behavior of SPA versus the amplitude of volatility fluctuations, by increasing the cross correlation between the noise sources in the Heston model. PMID:23944522
Amplification effects on the transmission and reflexion phases in 1D periodic systems
International Nuclear Information System (INIS)
We investigate the localization recently observed for locally non-hermitian Hamiltonians by studying the effect of the amplification on the scaling behavior of the transmission and reflection phases in 1D periodic chains of ?-potentials. The amplification here is represented by an imaginary term added to the on-site potential. It is found that both phases of the transmission and reflection amplitudes are strongly affected by the amplification term. In particular, the phases in the region of amplification become independent of the length scale while they oscillate strongly near the maximum transmission (or reflection). The interference effects on the phase in passive systems are used to interpret those observed in the presence of amplification. The phases of the transmission and reflection are found to oscillate in passive systems with increasing periods in the allowed band for the transmission phase while for the reflection phase, its initial value is always less than ?/2 in this band. (author)
BeppoSAX observations of the long period polar system V1309 Ori
De Martino, D; Matt, G; Mouchet, M; Belloni, T; Beuermann, K; Chiappetti, L; Done, C; Gõnsicke, B T; La Franca, F; Mukai, K
We present BeppoSAX observations of the peculiar long period polar system V1309 Ori (RXJ0515.6+0105). The source was detected simultaneously at soft and, for the first time, at hard X-rays with the LECS and the MECS detectors. Both, the LECS and the MECS light curves are irregular with a bursting/flaring type behaviour indicating inhomogeneous accretion onto the white dwarf. This peculiar variability, together with an extreme high soft-to-hard X-ray luminosity ratio, indicates that in V1309 Ori accretion occurs predominantly in highly compressed chunks or ``blobs'' of matter. From coordinated ESO optical spectroscopy, we find indications that the magnetic field strength of the white dwarf is < 70 MG, not expected either from the 8 hr orbital period synchronism or from the strong soft-to-hard X-ray ratio suggesting alternative solutions for sustaining synchronism in this system.
Reverse resonance in stock prices of financial system with periodic information
Li, Jiang-Cheng; Mei, Dong-Cheng
We investigate the stochastic resonance of the stock prices in a finance system with the Heston model. The extrinsic and intrinsic periodic information are introduced into the stochastic differential equations of the Heston model for stock price by focusing on the signal power amplification (SPA). We find that for both cases of extrinsic and intrinsic periodic information a phenomenon of reverse resonance emerges in the behaviors of SPA as a function of the system and external driving parameters. Moreover, in both cases, a phenomenon of double reverse resonance is observed in the behavior of SPA versus the amplitude of volatility fluctuations, by increasing the cross correlation between the noise sources in the Heston model.
Amplification Effects on the Transmission and Reflexion Phases in 1D Periodic Systems
Zekri, N; Maarouf, S
We investigate the localization observed recently for locally non-hermitian Hamiltonians by studying the effect of the amplification on the scaling behavior of the transmission and reflection phases in 1D periodic chains of added to the on-site potential. It is found that both phases of the transmission and reflection amplitudes are strongly affected by the amplification term. In particular, the phases in the region of amplification become independent of the length scale while they oscillate strongly near the maximum transmission (or reflection). The interference effects on the phase in passive systems are used to interpret those observed in the presence of amplification. The phases of the transmission and reflection are found to oscillate in passive systems whith increasing periods in the allowed band for the transmission phase while for the reflection phase, its initial value is always less than $\\pi /2$ in this band.
High-frequency approximation for periodically driven quantum systems from a Floquet-space perspective
Eckardt, Andrķ; Anisimovas, Egidijus
We derive a systematic high-frequency expansion for the effective Hamiltonian and the micromotion operator of periodically driven quantum systems. Our approach is based on the block diagonalization of the quasienergy operator in the extended Floquet Hilbert space by means of degenerate perturbation theory. The final results are equivalent to those obtained within a different approach [Phys.\\ Rev.\\ A {\\bf 68}, 013820 (2003), Phys.\\ Rev.\\ X {\\bf 4}, 031027 (2014)] and can also...
Van der Waals forces from first principles for periodic systems: Application to graphene-water interactions
Partovi-Azar, Pouya
We extend the method of Silvestrelli [P. L. Silvestrelli, J. Chem. Phys. 139, 054106 (2013)] to approximate long-range van der Waals interactions at the density functional theory level based on maximally localized Wannier functions combined with the quantum harmonic oscillator model, to periodic systems. Applying this scheme to study London dispersion forces between graphene and water layers, we demonstrate that collective many-body effects beyond simple additive pair-wise interactions are essential to accurately describe van der Waals forces.
Non-linear second-order periodic systems with non-smooth potential
Papageorgiou, Evgenia H.; Papageorgiou, Nikolaos S.
In this paper we study second order non-linear periodic systems driven by the ordinary vector $p$-Laplacian with a non-smooth, locally Lipschitz potential function. Our approach is variational and it is based on the non-smooth critical point theory. We prove existence and multiplicity results under general growth conditions on the potential function. Then we establish the existence of non-trivial homoclinic (to zero) solutions. Our theorem appears to be the first such result...
Renal tubular dysfunction presenting as recurrent hypokalemic periodic quadriparesis in systemic lupus erythematosus.
Prasad, D; Agarwal, D; Malhotra, V; Beniwal, P
We report recurrent hypokalemic periodic quadriparesis in a 30-year-old woman. Patient had also symptoms of multiple large and small joint pain, recurrent oral ulceration, photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus (SLE) with distal tubular acidosis. Our patient was successfully treated with oral potassium chloride, sodium bicarbonate, hydroxychloroquine and a short course of steroids. Thus, tubular dysfunction should be carefully assessed in patients with SLE. PMID:25249723
Renal tubular dysfunction presenting as recurrent hypokalemic periodic quadriparesis in systemic lupus erythematosus
Prasad, D.; Agarwal, D.; Malhotra, V.; Beniwal, P.
We report recurrent hypokalemic periodic quadriparesis in a 30-year-old woman. Patient had also symptoms of multiple large and small joint pain, recurrent oral ulceration, photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus (SLE) with distal tubular acidosis. Our patient was successfully treated with oral potassium chloride, sodium bicarbonate, hydroxychloroquine and a short course of steroids. Thus, tubular dysfunct...
Periodic systems of frustrated fluid films and ½ bicontinuous ╗ cubic structures in liquid crystals
CHARVOLIN, J; Sadoc, J F
We consider periodic organizations of two fluid media separated by interfaces in which interactions between the two media, normal to the interfaces, maintain constant distances between interfaces and constraints within each medium, parallel to the interfaces, control interfacial curvatures. The structures must therefore conciliate the constant interfacial distances and curvatures imposed by the thermodynamical parameters of the systems. This is a purely geometrical problem whose solutions con...
Periodic movements of the legs during sleep associated with rises in systemic blood pressure.
Ali, Nj; Davies, Rj; Fleetham, Ja; Stradling, Jr
We report the relationship between periodic leg movements during sleep and recurrent rises in systemic blood pressure in a patient with narcolepsy. The mean increase in systolic blood pressure following leg movements was 23%, which is of the same order as the rises seen in patients with obstructive sleep apnea. Following treatment with temazepam, the swings in blood pressure were unchanged despite considerably less electroencephalographic evidence of cortical arousal.
Time-periodic solutions to the full Navier¢Stokes¢Fourier system.
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Mucha, P.; Novotn², A.; Pokorn², M.
Ro?. 204, ?. 3 (2012), s. 745-786. ISSN 0003-9527 R&D Projects: GA ?R GA201/09/0917; GA MŖk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : compressible Navier¢Stokes¢Fourier system * time-periodic solution * weak solution Subject RIV: BA - General Mathematics Impact factor: 2.292, year: 2012 http://www. springerlink .com/content/3t5r85w616158561/
The HD 192263 system: planetary orbital period and stellar variability disentangled
Dragomir, Diana; Henry, Gregory W; Ciardi, David R; Fischer, Debra A; Howard, Andrew W; Jensen, Eric L N; Laughlin, Gregory; Mahadevan, Suvrath; Matthews, Jaymie M; Pilyavsky, Genady; von Braun, Kaspar; Wang, Sharon X; Wright, Jason T
As part of the Transit Ephemeris Refinement and Monitoring Survey (TERMS), we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 \\pm 0.0022 days. We use 10 years of Automated Photoelectric Telescope (APT) photometry to analyze the stellar variability and search for planetary transits. We find continuing evidence of spot activity with periods near 23.4 days. The shape of the corresponding photometric variations changes over time, giving rise to not one but several Fourier peaks near this value. However, none of these frequencies coincides with the planet's orbital period and thus we find no evidence of star-planet interactions in the system. We a...
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As part of the Transit Ephemeris Refinement and Monitoring Survey, we present new radial velocities and photometry of the HD 192263 system. Our analysis of the already available Keck-HIRES and CORALIE radial velocity measurements together with the five new Keck measurements we report in this paper results in improved orbital parameters for the system. We derive constraints on the size and phase location of the transit window for HD 192263b, a Jupiter-mass planet with a period of 24.3587 ▒ 0.0022 days. We use 10 years of Automated Photoelectric Telescope photometry to analyze the stellar variability and search for planetary transits. We find continuing evidence of spot activity with periods near 23.4 days. The shape of the corresponding photometric variations changes over time, giving rise to not one but several Fourier peaks near this value. However, none of these frequencies coincides with the planet's orbital period and thus we find no evidence of star-planet interactions in the system. We attribute the ?23 day variability to stellar rotation. There are also indications of spot variations on longer (8 years) timescales. Finally, we use the photometric data to exclude transits for a planet with the predicted radius of 1.09 RJ , and as small as 0.79 RJ .
Interband coherence induced correction to adiabatic pumping in periodically driven systems
Wang, Hailong; Zhou, Longwen; Gong, Jiangbin
Periodic driving can create topological phases of matter absent in static systems. In terms of the displacement of the position expectation value of a time-evolving wave packet in a closed system, a type of adiabatic dynamics in periodically driven systems is studied for general initial states possessing coherence between different Floquet bands. Under one symmetry assumption, the displacement of the wave-packet center over one adiabatic cycle is found to consist of two components independent of the time scale of the adiabatic cycle: a weighted integral of the Berry curvature summed over all Floquet bands, plus an interband coherence induced correction. The found correction is beyond a naive application of the quantum adiabatic theorem but survives in the adiabatic limit due to interband coherence. Our theoretical results are hence of general interest towards an improved understanding of the quantum adiabatic theorem. Our theory is checked using a periodically driven superlattice model with nontrivial topological phases. In addition to probing topological phase transitions, the adiabatic dynamics studied in this work is now also anticipated to be useful in manifesting coherence and decoherence effects in the representation of Floquet bands.
Accurate frequency domain measurement of the best linear time-invariant approximation of linear time-periodic systems including the quantification of the time-periodic distortions
Louarroudi, E.; Pintelon, R.; Lataire, J.
Time-periodic (TP) phenomena occurring, for instance, in wind turbines, helicopters, anisotropic shaft-bearing systems, and cardiovascular/respiratory systems, are often not addressed when classical frequency response function (FRF) measurements are performed. As the traditional FRF concept is based on the linear time-invariant (LTI) system theory, it is only approximately valid for systems with varying dynamics. Accordingly, the quantification of any deviation from this ideal LTI framework is more than welcome. The ōmeasure of deviationö allows us to define the notion of the best LTI (BLTI) approximation, which yields the best - in mean square sense - LTI description of a linear time-periodic LTP system. By taking into consideration the TP effects, it is shown in this paper that the variability of the BLTI measurement can be reduced significantly compared with that of classical FRF estimators. From a single experiment, the proposed identification methods can handle (non-)linear time-periodic [(N)LTP] systems in open-loop with a quantification of (i) the noise and/or the NL distortions, (ii) the TP distortions and (iii) the transient (leakage) errors. Besides, a geometrical interpretation of the BLTI approximation is provided, leading to a framework called vector FRF analysis. The theory presented is supported by numerical simulations as well as real measurements mimicking the well-known mechanical Mathieu oscillator.
Magnet power supply control system for CSRm super-long-period slow extraction
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In order to realize the HIRFL-CSR super-long-period slow extraction, the distributed control system of the CSR main ring (CSRm) power supply is designed based on high-speed ethernet, with the controller of the power supply employing ARM + DSP architecture. The control cycle adopts multipart handling mechanism to solve the problem that the waveform data is too large to be stored in the controller. The control system has been tested in the HIRFL-CSR, and successfully conducted the carbon ion's ten-thousand-second slow extraction. (authors)
Evaluation of raw milk quality in different production systems and periods of the year
Scientific Electronic Library Online (English)
Marcos Inßcio, Marcondes; Daniele Canabrava, Jßcome; Alex Lopes da, Silva; Luciana Navajas, Renn¾; Ana Clarissa dos Santos, Pires.
Full Text Available The objective of this study was to evaluate the quality of raw milk in different production systems and its variation throughout the year. The data were collected from 943 dairy farms in the South, Central-West and Central regions of the state of Minas Gerais, and in Vale do ParaĒba, in the state of [...] SŃo Paulo, Brazil. The data were collected in the period from January 2009 to September 2011, in a total of 18,206 samples. The properties were divided into confinement, semi-confinement and extensive production systems. The evaluated factors were somatic cell count (SCC), total bacterial count (TBC) and protein and fat contents. There was no effect of production system on the contents of protein, fat and SCC. Total bacterial count, however, was affected by production. Seasonal variations were found for SCC, TBC, protein and fat; the highest protein values were found from March to June; the highest fat contents were obtained from May to August; and TBC and SCC, from December to March. The production system does not interfere with the percentage of fat and protein and SCC of the milk. However, confinement systems present a better TBC content. Both month and year are factors that interfere with TBC, SCC, protein and milk fat, and the best patterns are found in the coldest periods of the year.
Phased mission modelling of systems with maintenance-free operating periods using simulated Petri nets
Energy Technology Data Exchange (ETDEWEB)
Chew, S.P.; Dunnett, S.J. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom); Andrews, J.D. [Department of Aeronautical and Automotive Engineering, Loughborough University, Loughborough, Leics (United Kingdom)], E-mail: firstname.lastname@example.com
A common scenario in engineering is that of a system which operates throughout several sequential and distinct periods of time, during which the modes and consequences of failure differ from one another. This type of operation is known as a phased mission, and for the mission to be a success the system must successfully operate throughout all of the phases. Examples include a rocket launch and an aeroplane flight. Component or sub-system failures may occur at any time during the mission, yet not affect the system performance until the phase in which their condition is critical. This may mean that the transition from one phase to the next is a critical event that leads to phase and mission failure, with the root cause being a component failure in a previous phase. A series of phased missions with no maintenance may be considered as a maintenance-free operating period (MFOP). This paper describes the use of a Petri net (PN) to model the reliability of the MFOP and phased missions scenario. The model uses Monte-Carlo simulation to obtain its results, and due to the modelling power of PNs, can consider complexities such as component failure rate interdependencies and mission abandonment. The model operates three different types of PN which interact to provide the overall system reliability modelling. The model is demonstrated and validated by considering two simple examples that can be solved analytically.
A Multiple Period Problem in Distributed Energy Management Systems Considering CO2 Emissions
Muroda, Yuki; Miyamoto, Toshiyuki; Mori, Kazuyuki; Kitamura, Shoichi; Yamamoto, Takaya
Consider a special district (group) which is composed of multiple companies (agents), and where each agent responds to an energy demand and has a CO2 emission allowance imposed. A distributed energy management system (DEMS) optimizes energy consumption of a group through energy trading in the group. In this paper, we extended the energy distribution decision and optimal planning problem in DEMSs from a single period problem to a multiple periods one. The extension enabled us to consider more realistic constraints such as demand patterns, the start-up cost, and minimum running/outage times of equipment. At first, we extended the market-oriented programming (MOP) method for deciding energy distribution to the multiple periods problem. The bidding strategy of each agent is formulated by a 0-1 mixed non-linear programming problem. Secondly, we proposed decomposing the problem into a set of single period problems in order to solve it faster. In order to decompose the problem, we proposed a CO2 emission allowance distribution method, called an EP method. We confirmed that the proposed method was able to produce solutions whose group costs were close to lower-bound group costs by computational experiments. In addition, we verified that reduction in computational time was achieved without losing the quality of solutions by using the EP method.
Internal space-time symmetries of particles derivable from periodic systems in optics
Kim, Y. S.
While modern optics is largely a physics of harmonic oscillators and two-by-two matrices, it is possible to learn about some hidden properties of the two-by-two matrix from optical systems. Since two-by-two matrices can be divided into three conjugate classes depending on their traces, optical systems force us to establish continuity from one class to another. It is noted that those three classes are equivalent to three different branches of Wigner's little groups dictating the internal space-time symmetries massive, massless, and imaginary-mass particles. It is shown that the periodic systems in optics can also be described by the same class-based matrix algebra. The optical system allow us to make continuous, but not analytic, transitions from massiv to massless, and massless to imaginary-mass cases.
Complex dynamics in unidirectionally coupled overdamped bistable systems subject to a time-periodic external signal
in, Visarath; Bulsara, Adi R.; Palacios, Antonio; Longhini, Patrick; Kho, Andy
Recently, we have studied the emergence of oscillatory behavior in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions [V. In et al., Phys. Rev. E 68, 045102(R) (2003).] The theoretical ideas have been validated in an experimental setup of N=3 coupled ferromagnetic cores subject to a dc external magnetic ōtargetö signal; the oscillations (corresponding to the periodic switching of each core between its stable steady states of magnetization) are triggered when the coupling constant crosses a threshold value, with the oscillation frequency exhibiting a characteristic scaling behavior with the ōseparationö of the coupling constant from its threshold value, as well as with the external signal amplitude. Here, we consider the system response to a time-periodic signal. We demonstrate experimentally that, depending on the signal amplitude and frequency, the response can be either synchronized to the signal frequency or to one-third this frequency. These phenomena afford unique techniques for time-periodic signal detection and characterization for a large class of sensors.
Self-isospectral tri-supersymmetry in PT-symmetric quantum systems with pure imaginary periodicity
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We study a reflectionless PT-symmetric quantum system described by the pair of complexified Scarf II potentials mutually displaced in the half of their pure imaginary period. Analyzing the rich set of intertwining discrete symmetries of the pair, we find an exotic supersymmetric structure based on three matrix differential operators that encode all the properties of the system, including its reflectionless (finite-gap) nature. The structure we revealed particularly sheds new light on the splitting of the discrete states into two families, related to the bound and resonance states in Hermitian Scarf II counterpart systems, on which two different series of irreducible representations of sl(2,C) are realized. - Highlights: ? A two-parametric family of pairs of reflectionless self-isospectral PT-symmetric systems is studied. ? A new exotic supersymmetric structure based on three integrals of motion is found. ? The splitting of the discrete states into two families is explained. ? The role of various discrete symmetries and the imaginary period is understood.
Weak-disorder-induced reduction of the lasing threshold in periodic systems
Alee, K. Shadak; Kumar, Randhir; Mujumdar, Sushil
We report numerical and experimental results on a finite-size, weakly disordered, amplifying multilayer with underlying periodicity. Computed transmission spectra evidence the simultaneous existence of perturbed band-edge modes and random lasing modes in exclusive configurations of disorder. A larger energy is seen to outcouple through the random lasing modes as compared to the band-edge lasing modes. With the gain being uniform across the band gap, this phenomenon originates from the increased quality factor of modes by the addition of disorder. Experiments carried out on a linear array of weakly disordered microresonators exhibit excellent agreement with the numerical observations, demonstrating threshold reduction by the addition of disorder in a periodic system.
1/1 resonant periodic orbits in three dimensional planetary systems
Antoniadou, Kyriaki I; Varvoglis, Harry
We study the dynamics of a two-planet system, which evolves being in a $1/1$ mean motion resonance (co-orbital motion) with non-zero mutual inclination. In particular, we examine the existence of bifurcations of periodic orbits from the planar to the spatial case. We find that such bifurcations exist only for planetary mass ratios $\\rho=\\frac{m_2}{m_1}<0.0205$. For $\\rho$ in the interval $0<\\rho<0.0205$, we compute the generated families of spatial periodic orbits and their linear stability. These spatial families form bridges, which start and end at the same planar family. Along them the mutual planetary inclination varies. We construct maps of dynamical stability and show the existence of regions of regular orbits in phase space.
Nonlinear stability of periodic traveling wave solutions of systems of viscous conservation laws in the generic case
Johnson, Mathew A.; zumbrun, Kevin
Extending previous results of Oh--Zumbrun and Johnson--Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling-wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions.
Health care system of the Republic of Serbia in the period 2004-2012
Directory of Open Access Journals (Sweden)
Gaji?-Stevanovi? Milena
Full Text Available Introduction. The backbone of Serbian health system forms the public healthcare provider network with 355 institutions and around 112,000 employees, owned and controlled by the Ministry of Health and financed mainly by the Republican Health Insurance Fund. The law recognizes private practice that was not included, till recently, in the public funding scheme. New Health Insurance Law (2005 decreased the number of entitlements in the basic health service package. It abolished the right to dental health care for adults (exceptions are: children, older than 65, pregnant women and emergency cases as well as the right to compensate travel expenses. The aim of this study was to evaluate the effects of health care system of the Republic of Serbia and indicate parameters that determine the state of health of the population, on the ground of data obtained by the Institute of Public Health of Serbia. Results. In the period 2004-2012, cardiovascular diseases represented the main cause of illness in Serbia (50%. In 2012 digestive system diseases were on the second place. Neoplasm and nervous system diseases were on the third place. From 2007 to 2012 there was slight decline in the birth rate and number of deaths, but the death rate increased from 13.9 to 14.2. Health care system in Serbia is funded through the combination of public finances and private contributions. Primary care is provided in 158 health care centres and health care stations, secondary and tertiary care services are offered in general hospitals, specialized hospitals, clinics, clinico-hospital centers and clinical centres. Conclusion. A significant but not satisfactory progress has been achieved in the field of health status indicators as the most important outcome of the final performance of the health system. The transition of public health care system in Serbia since the communist period to present and slow integration with European Union is unfinished process.
XIX Mendeleev Congress on general and applied chemistry. Abstract book in 4 volumes. Volume 3. Chemistry and technology of materials, including nanomaterials. Physico-chemical basis of metallurgical processes. Topical problems of chemical industry, evaluation of technical risks
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The abstracts of the XIX Mendeleev Congress on general and applied chemistry held 25-30 September 2011 in Volgograd are presented. The program includes the Congress plenary and section reports, poster presentations, symposia and round tables on key areas of chemical science and technology, and chemical education. The work of the Congress was held the following sections: 1. Fundamental problems of chemical sciences; 2. Chemistry and technology of materials, including nanomaterials; 3. Physicochemical basis of metallurgical processes; 4. Current issues of chemical production, technical risk assessment; 5. Chemical aspects of modern power and alternative energy sources; 6. Chemistry of fossil and renewable hydrocarbons; 7. Analytical chemistry: new methods and instruments for chemical research and analysis; 8. Chemical education. Volume 3 contains the reports correspondence section participants Chemistry and technology of materials, including nanomaterials, abstracts of oral and poster presentations, messages of correspondence participants at meetings of the sections: Physicochemical basis of metallurgical processes; Topical issues of chemical production, technical risk assessment, reports roundtable Interaction chemistry and business, as well as an author index
Tunneling Dynamics of Dipolar Bosonic System with Periodically Modulated s-wave Scattering
International Nuclear Information System (INIS)
Within the mean-field three-site BoseŚHubbard model, the tunneling dynamics of dipolar bosonic gas with a periodically modulation of s-wave scattering is investigated. The system experiences complex and rich coherent tunneling (CT)-coherent destruction of tunneling (CDT) transitions resulting from the correlated effect among the next-neighbor dipole-dipole interaction, the on-site interaction and the modulated s-wave scattering. In particular, The region of the modulated s-wave scattering for generating CT (CDT) is the widest (narrowest) when the on-site interaction and the next-neighbor dipole-dipole interaction have some correlated values, which are closely related to the tunneling energy and the interaction energy of the system. The correlated values for appearing CDT can be theoretically gained from the tunneling energy and the interaction energy of the system. (general)
Generation of optical and matter-wave solitons in binary systems with a periodically modulated coupling
International Nuclear Information System (INIS)
We present a systematic study of the generation of the array of optical or matter-wave kinks (dark solitons) in the ground state (GS) of binary systems. We consider quasi-one-dimensional systems described by a pair of nonlinear Schroedinger (NLSE's) or Gross-Pitaevskii equations (GPE's), which are coupled by the linear mixing, with local strength ?, and by nonlinear interactions. We assume the self-repulsive nonlinearity in both components, and include the effects of a harmonic trapping potential, while the nonlinear interaction between the components may be both repulsive and attractive. The model may be realized in terms of periodically modulated slab waveguides in nonlinear optics and also in Bose-Einstein condensates. Depending on the sign and strengths of the linear and nonlinear couplings between the components, the ground states in such binary systems may be symmetric, antisymmetric, or asymmetric. In this work, we introduce a periodic spatial modulation of the linear coupling, making ? an odd or even function of the coordinate (x). The sign flips of ?(x) strongly modify the structure of the GS in the binary system, as the relative sign of its components tends to lock to the local sign of ?. Using a systematic numerical analysis and an analytic approximation, we demonstrate that the GS of the trapped system contains one or several kinks (dark solitons) in one component, while the other component does not change its sign. The final results are presented in t. The final results are presented in the form of maps showing the number of kinks in the GS as a function of the system's parameters, with the odd (even) modulation function giving rise to the odd (even) number of the kinks. The modulation of ?(x) also produces a strong effect on the transition between states with nearly equal and strongly unequal amplitudes of the two components.
Soliton defects in one-gap periodic system and exotic supersymmetry
Arancibia, Adrißn; Correa, Francisco; Jakubsk², VĒt; Mateos Guilarte, Juan; Plyushchay, Mikhail S.
By applying Darboux-Crum transformations to the quantum one-gap Lamķ system, we introduce an arbitrary countable number of bound states into forbidden bands. The perturbed potentials are reflectionless and contain two types of soliton defects in the periodic background. The bound states with a finite number of nodes are supported in the lower forbidden band by the periodicity defects of the potential well type, while the pulse-type bound states in the gap have an infinite number of nodes and are trapped by defects of the compression modulations nature. We investigate the exotic nonlinear N =4 supersymmetric structure in such paired Schr÷dinger systems, which extends an ordinary N =2 supersymmetry and involves two bosonic generators composed from Lax-Novikov integrals of the subsystems. One of the bosonic integrals has a nature of a central charge and allows us to liaise the obtained systems with the stationary equations of the Korteweg-de Vries and modified Korteweg-de Vries hierarchies. This exotic supersymmetry opens the way for the construction of self-consistent condensates based on the Bogoliubov-de Gennes equations and associated with them new solutions to the Gross-Neveu model. They correspond to the kink or kink-antikink defects of the crystalline background in dependence on whether the exotic supersymmetry is unbroken or spontaneously broken.
Soliton defects in one-gap periodic system and exotic supersymmetry
Arancibia, Adrian; Jakubsky, Vit; Guilarte, Juan Mateos; Plyushchay, Mikhail S
By applying Darboux-Crum transformations to the quantum one-gap Lame system, we introduce an arbitrary countable number of bound states into forbidden bands. The perturbed potentials are reflectionless and contain two types of soliton defects in the periodic background. The bound states with finite number of nodes are supported in the lower forbidden band by the periodicity defects of the potential well type, while the pulse type bound states in the gap have infinite number of nodes and are trapped by defects of the compression modulations nature. We investigate the exotic nonlinear N=4 supersymmetric structure in such paired Schrodinger systems, which extends an ordinary N=2 supersymmetry and involves two bosonic generators composed from Lax-Novikov integrals of the subsystems. One of the bosonic integrals has a nature of a central charge, and allows us to liaise the obtained systems with the stationary equations of the Korteweg-de Vries and modified Korteweg-de Vries hierarchies. This exotic supersymmetry o...
Design of tapered arm impulse radiating antenna with log periodic lens system for skin cancer treatment.
Petrishia, A; Sasikala, M
A Prolate-Spheroidal Impulse Radiating Antenna (PSIRA) is used as a non-invasive technique for generating an electromagnetic implosion to kill melanoma cells. It can launch and focus fast (100?ps) high voltage (>50?KV) pulses into the biological targets. It can be used to obtain electromagnetic focusing on the target to reduce the damage to the tissue layers surrounding the target (skin). The main aim of this work is to improve the gain of the antenna, enhance the electric field intensity and to reduce the spot size at the focal point. In this work the PSIRA with tapered arm is designed to increase the gain of the antenna. The log periodic lens system is designed to enhance the electric field and reduce the spot size. The IRA with tapered arms located at the position of ??=?60░ gives a gain improvement of 14.28% when compared to a traditional IRA. In this work a 10-layer dielectric lens system is designed to match the 100?ps pulses to the skin phantom. Simulation results show that the electric field is increased by a factor of 2. The spot size is reduced from 1?cm to 0.75?cm at the focal point where the target is placed. The proposed Log periodic lens system provides an increase in electric field amplitude and reduction in spot size. PMID:24548051
Harnessing intrinsic localized modes to identify impurities in nonlinear periodic systems
Thota, M.; Harne, R. L.; Wang, K. W.
Intrinsic localized modes (ILMs) are concentrations of vibrational energy in periodic systems/lattices due to the combined influences of nonlinearity and discreteness. Moreover, ILMs can move within the system and may strongly interact with an impurity, such as a stiffness change, mass variation, etc. Numerous scientific fields have uncovered examples and evidence of ILMs, motivating a multidisciplinary pursuit to rigorously understand the underlying principles. In spite of the diverse technical studies, a characterization of ILM interaction behaviors with multiple impurities in dissipative lattices remains outstanding. The insights on such behaviors may be broadly useful when dynamic measurements are the only accessible features of the periodic system. For instance, one may guide an ILM within the lattice using a deliberately applied and steered impurity and harness the observed interaction behaviors with a second, static (immovable) impurity/defect to identify how the underlying lattice is different at the second, defected site, whether or not one knew the position of the defect a priori. In this spirit, this research studies, analyzes, and characterizes the interaction types amongst an ILM and multiple impurities, and devises a method to identify a static defect impurity using quantitatively and qualitatively distinct interaction phenomena. The method is found to be robust to moderate levels of lattice stiffness heterogeneity and is applicable to monitor various property changes that represent impurities. Finally, experimental studies verify that ILMs interact with multiple impurities in unique ways such that defect features may be effectively identified.
BeppoSAX observations of the long period polar system V1309 Ori
Martino, D.; Barcaroli, R.; Matt, G.; Mouchet, M.; Belloni, T.; Beuermann, K.; Chiapetti, L.; Done, C.; Gaensicke, B. T.; La Franca, F.; Mukai, K.
We present BeppoSAX observations of the peculiar long period polar system V1309 Ori (RXJ0515.6+0105). The source was detected simultaneously at soft and, for the first time, at hard X-rays with the LECS and the MECS detectors. Both, the LECS and the MECS light curves are irregular with a bursting/flaring type behaviour indicating inhomogeneous accretion onto the white dwarf. This peculiar variability, together with an extreme high soft-to-hard X-ray luminosity ratio, indicat...
Triple scale analysis of periodic solutions and resonance of some asymmetric non linear vibrating systems
Rousselet, Bernard
We consider {\\it small solutions} of a vibrating mechanical system with smooth non-linearities for which we provide an approximate solution by using a triple scale analysis; a rigorous proof of convergence of the triple scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighbourhood of a primary resonance. The amplitude of the response with respect to the frequency forcing is described and it is related to the frequency of a free periodic vibration.
Complex formation of elements of the third group of the periodic system with chromazurol s
International Nuclear Information System (INIS)
An attempt is made to establish the composition and spectrophotometric characteristics of colored complexes of elements of the third group of the periodic system, produced with chromazurol S purified according to the procedure described. For a comparison of data on complexes of various elements with this reagent the authors used published results of an investigation of the complex formation of aluminium and those results they themselves obtained. The complex formation of aluminum, gallium, indium, scandium, yttrium, lanthanum, and cerium (III) were studied with the chromazurol S. The mechanism of the reaction of aluminum, gallium, scandium, and yttrium with chromazurol S was examined
Ultra-Short-Period Binary Systems in the OGLE Fields Toward the Galactic Bulge
Soszynski, I.; Stepien, K.; Pilecki, B.; Mroz, P.; Udalski, A.; Szymanski, M. K.; Pietrzynski, G.; Wyrzykowski, \\L; Ulaczyk, K.; Poleski, R.; Kozlowski, S; Pietrukowicz, P.; Skowron, J.; M. Pawlak
We present a sample of 242 ultra-short-period (P < 0.22 d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve morphology, we divide the sample into candidates for contact binaries and non-contact binaries. In the latter group we distinguish binary systems consisting of a cool main-sequence star and a B-type subdwarf (HW Vir stars) and candidates for cataclysmic variables, including five eclipsing dwarf nov...
Buying TimeŚThe Immune System Determinants of the Incubation Period to Respiratory Viruses
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Thomas M. Moran
Full Text Available Respiratory viruses cause disease in humans characterized by an abrupt onset of symptoms. Studies in humans and animal models have shown that symptoms are not immediate and appear days or even weeks after infection. Since the initial symptoms are a manifestation of virus recognition by elements of the innate immune response, early virus replication must go largely undetected. The interval between infection and the emergence of symptoms is called the incubation period and is widely used as a clinical score. While incubation periods have been described for many virus infections the underlying mechanism for this asymptomatic phase has not been comprehensively documented. Here we review studies of the interaction between human pathogenic respiratory RNA viruses and the host with a particular emphasis on the mechanisms used by viruses to inhibit immunity. We discuss the concept of the ōstealth phaseö, defined as the time between infection and the earliest detectable inflammatory response. We propose that the ōstealth phaseö phenomenon is primarily responsible for the suppression of symptoms during the incubation period and results from viral antagonism that inhibits major pathways of the innate immune system allowing an extended time of unhindered virus replication.
CORS Baade-Wesselink method in the Walraven photometric system: the period-radius and the period-luminosity relation of classical Cepheids
Molinaro, R.; Ripepi, V.; Marconi, M.; Bono, G.; Lub, J.; Pedicelli, S.; Pel, J. W.
We present a new derivation of the CORS Baade-Wesselink method in the Walraven photometric system. We solved the complete Baade-Wesselink equation by calibrating the surface brightness function with a recent grid of atmosphere models. The new approach was adopted to estimate the mean radii of a sample of Galactic Cepheids for which are available precise light curves in the Walraven bands. Current radii agree, within the errors, quite well with Cepheid radii based on recent optical and near-infrared interferometric measurements. We also tested the impact of the projection factor on the period-radius relation using two different values (p= 1.36, 1.27) that bracket the estimates available in the literature. We found that the agreement of our period-radius relation with similar empirical and theoretical period-radius relations in the recent literature improves by changing the projection factor from p= 1.36 to 1.27. Our period-radius relation is log R= (0.75 ▒ 0.03)log P+ (1.10 ▒ 0.03), with an rms = 0.03 dex. Thanks to accurate estimates of the effective temperature of the selected Cepheids, we also derived the period-luminosity relation in the V band and we found MV= (-2.78 ▒ 0.11)log P+ (-1.42 ▒ 0.11) with rms = 0.13 mag, for p= 1.27. It agrees quite well with recent results in the literature, while the relation for p= 1.36 deviates by more than 2?. We conclude that, even taking into account the intrinsic dispersion of the obtained period-luminosity relations that is roughly of the same order of magnitude as the effect of the projection factor, the results of this paper seem to favour the value p= 1.27.
Connectivity of Owens River System Paleo-Lakes During Quaternary Glacial Periods: The Strontium Isotope Record
Stewart, B. W.; Roof, S.; Boulanger, J. R.; Lowenstein, T. K.
The Owens River system comprises a series of lakes, some now dry (Owens, China, Searles, Panamint, and Death Valley Lakes), that are thought to have been hydrologically connected during pluvial (glacial) periods. The paleohydrology of this system provides information about past climate conditions in the Great Basin region of western North America. Strontium (Sr) isotopes in chemical sediments from these former lakes can be used to trace water and dissolved cation flow from the head of the hydrologic system (Owens Lake, fed from eastern Sierra Nevada watersheds) to its terminus at Death Valley. Previous work has shown that Owens Lake waters, as reflected in carbonate sediments, remained isotopically homogeneous (0.7091-0.7093) over the past ~25 ka, even during the transition from glacial to interglacial conditions. Moreover, Sr isotope data from Death Valley core DV93-1 spanning the last ~100 ka (0.7132-0.7152) are clearly distinct from Owens Lake values (Sr isotope data from Z. Peterman, USGS). We measured Sr isotope ratios in carbonate (tufa and beach rock) from the Panamint Valley. These samples were deposited during relative highstands of Panamint Lake, and thus could be influenced by overflow waters derived from Owens Lake. Isotope ratios fall in the range 0.7098 to 0.7104, which is clearly distinct from sulfate from Panamint core PAN-3 (0.7159). The core sulfate most likely reflects local spring water (and cation) sources during relatively dry periods, whereas the carbonate appears to contain a very significant contribution from upstream lacustrine systems. These preliminary data suggest that Panamint Lake was linked to the rest of the Owens River system during highstands, and that a majority of its cation load during these times could be derived ultimately from the eastern Sierra Nevada. At present, there is no clear Sr isotope evidence of overflow from Panamint Lake to Death Valley Lake, suggesting that local cation sources predominate in the Death Valley system, even if water did spill over from Panamint Lake during pluvial periods.
CORS Baade-Wesselink method in the Walraven photometric system: the Period-Radius and the Period-Luminosity relation of Classical Cepheids
Molinaro, R; Marconi, M; Bono, G; Lub, J; Pedicelli, S; Pel, J W
We present a new derivation of the CORS Baade-Wesselink method in the Walraven photometric system. We solved the complete Baade-Wesselink equation by calibrating the surface brightness function with a recent grid of atmosphere models. The new approach was adopted to estimate the mean radii of a sample of Galactic Cepheids for which are available precise light curves in the Walraven bands. Current radii agree, within the errors, quite well with Cepheid radii based on recent optical and near-infrared interferometric measurements. We also tested the impact of the projection factor on the Period-Radius relation using two different values (p=1.36, p=1.27) that bracket the estimates available in the literature. We found that the agreement of our Period-Radius relation with similar empirical and theoretical Period-Radius relations in the recent literature, improves by changing the projection factor from p=1.36 to p=1.27. Our Period-Radius relation is log(R)=(0.75\\pm 0.03)log(P)+(1.10 \\pm 0.03), with a rms=0.03 dex. ...
Numerical continuation of families of heteroclinic connections between periodic orbits in a Hamiltonian system
International Nuclear Information System (INIS)
This paper is devoted to the numerical computation and continuation of families of heteroclinic connections between hyperbolic periodic orbits (POs) of a Hamiltonian system. We describe a method that requires the numerical continuation of a nonlinear system that involves the initial conditions of the two POs, the linear approximations of the corresponding manifolds and a point in a given Poincarķ section where the unstable and stable manifolds match. The method is applied to compute families of heteroclinic orbits between planar Lyapunov POs around the collinear equilibrium points of the restricted three-body problem in different scenarios. In one of them, for the Sun¢Jupiter mass parameter, we provide energy ranges for which the transition between different resonances is possible. (paper)
Non-linear second-order periodic systems with non-smooth potential
Papageorgiou, E H; Papageorgiou, Evgenia H; Papageorgiou, Nikolaos S
In this paper we study second order non-linear periodic systems driven by the ordinary vector $p$-Laplacian with a non-smooth, locally Lipschitz potential function. Our approach is variational and it is based on the non-smooth critical point theory. We prove existence and multiplicity results under general growth conditions on the potential function. Then we establish the existence of non-trivial homoclinic (to zero) solutions. Our theorem appears to be the first such result (even for smooth problems) for systems monitored by the $p$-Laplacian. In the last section of the paper we examine the scalar \\hbox{non-linear} and semilinear problem. Our approach uses a generalized Landesman--Lazer type condition which generalizes previous ones used in the literature. Also for the semilinear case the problem is at resonance at any eigenvalue.
Quasi-periodic motions in families of dynamical systems order amidst chaos
Broer, Hendrik W; Sevryuk, Mikhail B
This book is on Kolmogorov-Arnol'd-Moser theory for quasi-periodic tori in dynamical systems. It gives an up-to-date report on the role parameters play for persis- tence of such tori, typically occuring on Cantor sets of positive Hausdorff measure inside phase and parameter space. The cases with preservation of symplectic or volume forms or time-reversal symmetries are included. The concepts of Whitney-smoothness and Diophantine approximation of Cantor sets on submanifolds of Euclidean space are treated, as well as Bruno's theory on analytic continuation of tori. Partly this material is new to Western mathematicians. The reader should be familiar with dynamical systems theory, differen- tial equations and some analysis. The book is directed to researchers, but its entrance level is introductory.
The ground state of binary systems with a periodic modulation of the linear coupling
Niederberger, Armand; Lewenstein, Maciej
We consider a quasi-one-dimensional two-component systm, described by a pair of Nonlinear Schr\\"{o}dinger/Gross-Pitaevskii Equations (NLSEs/GPEs), which are coupled by the linear mixing, with local strength $\\Omega $, and by the nonlinear incoherent interaction. We assume the self-repulsive nonlinearity in both components, and include effects of a harmonic trapping potential. The model may be realized in terms of periodically modulated slab waveguides in nonlinear optics, and in Bose-Einstein condensates too. Depending on the strengths of the linear and nonlinear couplings between the components, the ground states (GSs) in such binary systems may be symmetric or asymmetric. In this work, we introduce a periodic spatial modulation of the linear coupling, making $\\Omega $ an odd, or even function of the coordinate. The sign flips of $\\Omega (x)$ strongly modify the structure of the GS in the binary system, as the relative sign of its components tends to lock to the local sign of $\\Omega $. Using a systematic nu...
Optimization of Water Circulation Period for the Culture of Goldfish with Spinach in Aquaponic System
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A. P. Shete
Full Text Available Experiment with varied water circulation periods having 4, 8, 12, and 24 hrs/day as T1, T2, T3 and T4, respectively in aquaponics, evaluated against a control (without aquaponics revealed higher fish and plant growth in T3 and T4. The mean growth of fish varied significantly among treatments showing higher growth in T4 and control followed by T3, T2 and T1. Survival rate was 100% in all the treatments as well as control. Percentage weight gain, SGR (% day-1 also showed the similar trend as that of growth showing T4 as better treatment immediately followed by T3 then T2 and T1. The system maintained favourable water quality throughout the experiment. The growth in T3 and T4 did not vary significantly and was higher than the T1, T2 and control. Also percentage length gain at the end of the trial was maximum in T3 and T4. The Chl (a+b content in the control was higher than all the treatments whereas, T4 showed the maximum concentration among treatments followed by T3, T2 and then T1. Comparison of all the growth attributes and water quality parameters indicated that water circulation can be reduced to 12 hrs/day for economically effective aquaponics and can be considered as optimum water circulation period for goldfish production in aquaponic system.
A periodic energy decomposition analysis method for the investigation of chemical bonding in extended systems
Raupach, Marc; Tonner, Ralf
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the bonding energy between two fragments (e.g., the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic, Pauli repulsion, and orbital relaxation energies. This is complemented by consideration of dispersion interactions via a pairwise scheme. One major extension toward a previous implementation [Philipsen and Baerends, J. Phys. Chem. B 110, 12470 (2006)] lies in the separate discussion of electrostatic and Pauli and the addition of a dispersion term. The pEDA presented here for an implementation based on atomic orbitals can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy, and k-space sampling. Four typical bonding scenarios for surface-adsorbate complexes were chosen to highlight the performance of the method representing insulating (CO on MgO(001)), metallic (H2 on M(001), M = Pd, Cu), and semiconducting (CO and C2H2 on Si(001)) substrates. These examples cover diverse substrates as well as bonding scenarios ranging from weakly interacting to covalent (shared electron and donor acceptor) bonding. The results presented lend confidence that the pEDA will be a powerful tool for the analysis of surface-adsorbate bonding in the future, enabling the transfer of concepts like ionic and covalent bonding, donor-acceptor interaction, steric repulsion, and others to extended systems.
Theory of the Quantized Hall Conductance in Periodic Systems: a Topological Analysis.
Czerwinski, Michael Joseph
The integral quantization of the Hall conductance in two-dimensional periodic systems is investigated from a topological point of view. Attention is focused on the contributions from the electronic sub-bands which arise from perturbed Landau levels. After reviewing the theoretical work leading to the identification of the Hall conductance as a topological quantum number, both a determination and interpretation of these quantized values for the sub-band conductances is made. It is shown that the Hall conductance of each sub-band can be regarded as the sum of two terms which will be referred to as classical and nonclassical. Although each of these contributions individually leads to a fractional conductance, the sum of these two contributions does indeed yield an integer. These integral conductances are found to be given by the solution of a simple Diophantine equation which depends on the periodic perturbation. A connection between the quantized value of the Hall conductance and the covering of real space by the zeroes of the sub-band wavefunctions allows for a determination of these conductances under more general potentials. A method is described for obtaining the conductance values from only those states bordering the Brillouin zone, and not the states in its interior. This method is demonstrated to give Hall conductances in agreement with those obtained from the Diophantine equation for the sinusoidal potential case explored earlier. Generalizing a simple gauge invariance argument from real space to k-space, a k-space 'vector potential' is introduced. This allows for a explicit identification of the Hall conductance with the phase winding number of the sub-band wavefunction around the Brillouin zone. The previously described division of the Hall conductance into classical and nonclassical contributions is in this way made more rigorous; based on periodicity considerations alone, these terms are identified as the winding numbers associated with (i) the basis states and (ii) the coefficients of these basis states, respectively. In this way a general Diophantine equation, independent of the periodic potential, is obtained. Finally, the use of the 'parallel transport' of state vectors in the determination of an overall phase convention for these states is described. This is seen to lead to a simple and straightforward method for determining the Hall conductance. This method is based on the states directly, without reference to the particular component wavefunctions of these states. Mention is made of the generality of calculations of this type, within the context of the geometric (or Berry) phases acquired by systems under an adiabatic modification of their environment.
Evaluation of radon mitigation systems in 14 houses over a two-year period
International Nuclear Information System (INIS)
Fourteen single-family detached houses in Spokane, Washington, and Coeur D'Alene, Idaho, were monitored for two years after high concentrations of indoor radon had been mitigated. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. To assess performance of mitigation systems during the second heating season after mitigation, radon concentrations in seven houses were monitored continuously for several weeks, mitigation systems in all houses were inspected, and selected other measurements were taken. In addition, occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation systems. Quarterly alpha-track measurements showed that radon levels had increased in most of the homes during many follow-up measurement periods when compared with concentrations measured immediately after mitigation. Mitigation-system performance was adversely affected by (1) accumulated outdoor debris blocking the outlets of subsurface pressurization pipes; (2) fans being turned off (e.g., because of excessive noise or vibration); (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans being turned off and fan speeds reduced; and (4) crawl-space vents being closed or sealed
Energy pay-back period analysis of stand-alone photovoltaic systems
Energy Technology Data Exchange (ETDEWEB)
Kaldellis, J.K.; Zafirakis, D. [Lab of Soft Energy Applications and Environmental Protection, TEI Piraeus, P.O. Box 41046, Athens 12201 (Greece); Kondili, E. [Optimisation of Production Systems Lab, Mechanical Eng. Dept., TEI of Piraeus, P.O. Box 41046, Athens 12201 (Greece)
The exploitation of solar energy by autonomous, photovoltaic (PV) based systems offers the opportunity for satisfying the electrification needs of numerous remote consumers worldwide in an environmentally friendly way. On the other hand, the sustainable character of these systems is strongly questioned by the energy intensity of processes involved in the various life cycle (LC) stages of the system components. Although there are several studies concerned with the estimation of the energy pay-back period (EPBP) for grid-connected systems, the same is not valid for stand-alone configurations. In this context, an integrated methodology is currently developed in order to estimate the EPBP of PV-battery (PV-Bat) configurations ensuring 100% energy autonomy. The main scope of the proposed analysis is to determine the optimum size of a corresponding system, comprised of multi-crystalline (mc-Si) PV modules and lead-acid (PbA) batteries, based on the criterion of minimum embodied energy, i.e. minimum EPBP. For this purpose, a representative case study examined considers the electrification needs of a typical remote consumer on the Island of Rhodes, Greece. According to the results obtained, the autonomous energy character of the system is reflected by the comparatively higher EPBP in comparison with the corresponding grid-connected option, nevertheless the PV-Bat configurations analyzed clearly constitute sustainable energy solutions. Finally, in order to increase the reliability of the calculation results, a sensitivity analysis is carried out, based on the variation of the input energy content data. (author)
Screening criteria of system structure and components to evaluate of aging in periodic safety review
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Periodic safety review(PSR) is considered to be the best way to obtain overall view of actual plant safety, to determine necessary or worthwhile changes that should be made in order to maintain a high level of safety and to improve the safety of older nuclear power plant to level comparable with that of modern plants. According to the nuclear power law, PSR must be applied to operating nuclear power plants. Evaluation item for PSR is composed of 12 factors. The object of Management of aging that one between 12 factors is to determine whether aging in a nuclear power plant (NPP) is being effectively managed so that required safety margins are maintained, and whether an adequate aging management program is in place for future plant operation. The object of this paper is to establish screening criteria and methodology for evaluation of aging management of periodic safety review(PSR). For this purpose, domestic nuclear laws related on PSR was investigated and made comparison with license renewal and maintenance rule. The evaluation scope for aging management of PSR is consists of system, structure and components(SSCs) on safety and stable operation of NPPs. The SSCs for aging evaluation of Kori 1 PSR was selected by screening criteria and methodology
Periodic dynamic systems for infected hosts and mosquitoes Sistemas dinŌmicos peri¾dicos para hospedeiros e mosquitos infectados
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W. M. Oliva
Full Text Available A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix one can state that either the infection peters out naturally (lambda 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.Desenvolveu-se um modelo matemßtico para analisar a dinŌmica das populań§es de indivĒduos e mosquitos infectados quando as populań§es de mosquitos sŃo peri¾dicas no tempo. Pela determinańŃo de um parŌmetro lambda (o raio espectral de uma matriz de monodromia pode-se estabelecer que a infecńŃo termina naturalmente (lambda 1 que a infecńŃo torna-se endĻmica. O modelo generaliza, para o caso de coeficientes peri¾dicos, modelos anteriores para malßria; como tambķm ķ uma variańŃo de modelo para a gonorrķia. A principal motivańŃo para a considerańŃo do modelo proposto foram os recentes estudos sobre mosquitos numa estańŃo experimental de arroz irrigado, na regiŃo Sudeste do Brasil.
Chemical effects of (n,2n) reactions on iodate and periodates systems
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The chemical consequences of (n,2n) reactions on cristalline sodium iodate and periodates were investigated measuring the initial yield and the post irradiation thermal annealing yields (900C) of the separated fractions I-, IO3- and IO4-. NaIO3, NaIO3.H2O and NaIO4, Na4H2IO6, Na4I2O9.3H2O containing 127I and 129I, or both, were irradiated with 14 MeV neutrons. Results obtained show different effects for each system and that 126I and 128I isotopes keep the same behaviour in the irradiated compounds containing only ?127I or 129I and in compounds having both 127I and 129I. Neither isotope effect nor qualitative differences on thermal annealing at 900C were observed. The annealed fractions in the three studied periodates were IO-3 and IO-4. These results differ from the ones reported previously for (n,?) reactions on the same compounds
Assessment of financial flow in the health system of Serbia in a period 2003-2006
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Gaji?-Stevanovi? Milena
Full Text Available Background/Aim. The main goal of every health policy is not merely the establishment of the health system sustainability, but the accessibility of health services to the whole population, as well. This objective is shared in European Union countries, and the consequence is the implementation of National Health Accounts (NHA. NHA, as a tool for evidence-based management, provides data regarding financial flow in health at national level and alows international comparability. The aim of this study was to determine Serbian overall health spending patterns by National Health Accounts, and to determine health care indices to provide policy makers with internationally comparable health indicators. Methods. A retrospective analysis of healthcare expenditures was obtained from the published final financial reports of relevant state institutions during a period of 2003 to 2006. The various sources of data on healthcare expenditures were connected according to instructions by the OECD 'A System of Health Accounts (SHA' Version 1.0. Results. The obtained results showed: health expenditures in Serbia made up 8.6%, 8.3%, 8.7% and 9 % of the GDP in 2003, 2004, 2005 and 2006, respectively; the Health Insurance Fund was a predominant financing source of the public sector with 93% in 2006; the largest part of the total health expenditures went towards hospitals and for health services; the expenditure per capita in 2006 was 365 US$; Serbian population finances the state institutions 'out of pocket' with 21.28% of their sources, which was 7.3% of the total healthcare expenditures, and the private institutions with 78.72% of their financial sources, which is 27% of the total healthcare expenditures. In 2006 Serbia allocated financial resources out of GDP in the amount similar to the European Unity, while comparing to the countries of the region, these funds were less only than in Bosnia and Herzegovina. This allocating of financial resources in total, however, was low as the consequence of relatively low level of GDP in Serbia. Conclusion. Establishing NHA provided a pattern of national healtcare spending and allowed a comparison of healthcare system in Serbia with the systems of other countries. Analysing a period 2003- 2006 revealed a similarity between Serbia and the countries of the European Unity in regard to the level of average financial resources allocation for healthcare expressed as a percentage of GDP, as well as in regard to financiers in the system of healthcare. A high purchasing power disparity, however, in healthcare services was observed between the population of Serbia and other European countries.
Spin Waves in a Ferromagnetic Film with a Periodic System of Antidots
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Full Text Available In the paper, spin waves in a thin film (composed of a uniaxial ferromagnet with a two-dimensional periodical system of antidots are studied. The film ferromagnet is considered to have the ōeasy axisö type. To describe such waves, the magnetostatic approximation with account for the magnetic dipole-dipole interaction, the exchange interaction and the anisotropy effects is used. For such waves, an equation for the magnetic potential is derived; for the case of remote antidots, the dispersion relation and the transverse wavenumber spectrum are found. For the case of a film thin compared to the exchange length and for the case of a film bounded by a high-conductivity metal, the longitudinal wavenumber spectrum and the frequency spectrum of such spin waves are also obtained.
Discharge formation systems for generating atomic iodine in a pulse-periodic oxygen-iodine laser
Aksinin, V. I.; Antsiferov, S. A.; Velikanov, S. D.; Gerasimov, A. Yu; Gostev, I. V.; Kazantsev, S. Yu; Kalinovskii, V. V.; Konovalov, V. V.; Kononov, I. G.; Mikhalkin, V. N.; Podlesnykh, S. V.; Sevryugin, I. V.; Firsov, K. N.
Generation characteristics of a pulse-periodic oxygen-iodine laser with the electro-discharge production of atomic iodine were compared with inductively stabilised edged or anisotropic- resistive cathodes used for ignition of the volume discharge. The discharge was initiated by the radiation of a barrier discharge from the side of a grid anode. It was found that at equal specific electrical energy depositions to the gas-discharge plasma, the system with the anisotropic-resistive cathode provides a more stable and uniform volume discharge with the possibility of varying the composition and pressure of working mixtures over a wide range and a greater specific extraction of laser energy is observed (up to 2.4 J L-1). At a high pulse repetition rate of laser pulses (50 - 100 Hz) and long duration of the pulse trains (longer than a minute) the surface of anisotropic-resistive cathode became eroded.
The prisons of the ōNew Argentinaö: Penitentiary system and Catholicism during the peronist period
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JeremĒas Silva
Full Text Available This study analyzes the relevance of the catholic religion in the penitenciary reform during the so-called ōclassicö peronist period, that is to say the first two peronist presidencies between 1946 and 1955. By exploring the rhetoric and rationalization articulated by Roberto Pettinato, the main responsible for the penitentiary system during the peronist administration, we seek to illuminate to what extent Catholicism provided the views to legitimize government policies and influenced the state institutions. To do so, in addition to examining the undertakings of the state bureaucracy, we reconstruct the daily life of the penitentiary institutions to shed light on how the public symbolism and official celebrations from the Direcci¾n General de Institutos Penales were penetrated by catholic rites, therefore demonstrating how Catholicism became influential in the prisons of the ōNew Argentinaö
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays.
Bi, Ping; Ruan, Shigui; Zhang, Xinan
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations. PMID:24985415
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays
International Nuclear Information System (INIS)
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations
The optimal P3M algorithm for computing electrostatic energies in periodic systems
Ballenegger, V; Holm, Ch; Lenz, O
We optimize Hockney and Eastwood's Particle-Particle Particle-Mesh (P3M) algorithm to achieve maximal accuracy in the electrostatic energies (instead of forces) in 3D periodic charged systems. To this end we construct an optimal influence function that minimizes the RMS errors in the energies. As a by-product we derive a new real-space cut-off correction term, give a transparent derivation of the systematic errors in terms of Madelung energies, and provide an accurate analytical estimate for the RMS error of the energies. This error estimate is a useful indicator of the accuracy of the computed energies, and allows an easy and precise determination of the optimal values of the various parameters in the algorithm (Ewald splitting parameter, mesh size and charge assignment order).
Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays
Energy Technology Data Exchange (ETDEWEB)
Bi, Ping [Department of Mathematics, Shanghai Key Laboratory of PMMP, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Center for Partial Differential Equations, East China Normal University, 500 Dongchuan Rd., Shanghai 200241 (China); Ruan, Shigui, E-mail: email@example.com [Department of Mathematics, University of Miami, Coral Gables, Florida 33124-4250 (United States); Zhang, Xinan [School of Mathematics and Statistics, Central China Normal University, Wuhan 430079 (China)
In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations.
Stochastic resonance in a time-delayed asymmetric bistable system with mixed periodic signal
International Nuclear Information System (INIS)
This paper studies the phenomenon of stochastic resonance in an asymmetric bistable system with time-delayed feedback and mixed periodic signal by using the theory of signal-to-noise ratio in the adiabatic limit. A general approximate Fokker¢Planck equation and the expression of the signal-to-noise ratio are derived through the small time delay approximation at both fundamental harmonics and mixed harmonics. The effects of the additive noise intensity Q, multiplicative noise intensity D, static asymmetry r and delay time ? on the signal-to-noise ratio are discussed. It is found that the higher mixed harmonics and the static asymmetry r can restrain stochastic resonance, and the delay time ? can enhance stochastic resonance. Moreover, the longer the delay time ? is, the larger the additive noise intensity Q and the multiplicative noise intensity D are, when the stochastic resonance appears. (general)
Stochastic Resonance of a Periodically Driven Bistable System with Two Different Kinds of Time Delays
International Nuclear Information System (INIS)
In this paper, we study the phenomenon of stochastic resonance (SR) in a periodically driven bistable system with correlations between multiplicative and additive white noise terms when there are two different kinds of time delays existed in the deterministic and fluctuating forces, respectively. Using the small time delay approximation and the theory of signal-to-noise ratio (SNR) in the adiabatic limit, the expression of SNR is obtained. The effects of the delay time ? in the deterministic force, and the delay time ? in the fluctuating force on SNR are discussed. Based on the numerical computation, it is found that: (i) There appears a reentrant transition between one peak and two peaks and then to one peak again in the curve of SNR when the value of the time delay ? is increased. (ii) SR can be realized by tuning the time delay ? or ? with fixed noise, i.e., delay-induced stochastic resonance (DSR) exists. (general)
Bifurcation and complex dynamics of a two-prey two-predator system concerning periodic biological and chemical control
International Nuclear Information System (INIS)
In this paper, we investigate the dynamic behaviors of a two-prey two-predator system with impulsive effect concerning biological and chemical control strategy-periodic releasing natural enemies and spraying pesticide at different fixed time. By applying the Floquet theory of linear periodic impulsive equation and small amplitude perturbation method, we prove that there exists a globally asymptotically stable two-prey-eradication periodic solution when the impulsive period is less than some critical value. The conditions for the permanence of the system are given, and meanwhile the conditions for the extinction of one of the two prey species and permanence of the remaining three species are given. Our results suggest a new approach in pest control. The target pest population can be driven to extinction and the non-target pest can be permanent by choosing impulsive period. With the increasing of the predation rate for the super competitor and impulsive period, the system displays complicated behaviors including a sequence of direct and inverse cascades of periodic-doubling, periodic-halfing, chaos, and symmetry breaking bifurcation
Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system
Battista, Emmanuele; Dell'Agnello, Simone; Esposito, Giampiero; Simo, Jules
Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics; i.e., at the Lagrangian libration points of stable equilibrium, the planetoid is not exactly at an equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we prove in detail that for collinear Lagrangian points the quantum corrections are also of the same order of magnitude in the Earth-Moon system. Third, we discuss the prospects of measuring, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. Therefore, the present paper investigates, eventually, a restricted three-body problem involving Earth, the Moon, and a solar sail. By taking into account the one-loop quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.
Assessment of the expected number and frequency of failures of periodically tested systems
International Nuclear Information System (INIS)
The safety and reliability analysis of any system necessarily requires first to model its behavior or its failure logic, and second to assess its performance by using the previously chosen model. Among these performance indicators there is the failure frequency. In spite of its interest, it is not very often used, except in the standards devoted to the so-called functional safety, in which its genuine nature is not always made explicit. A sound method dedicated to the modeling and computing of the failure frequency of periodically tested systems is proposed in this paper. This type of systems comprises components with an availability curve which is discontinuous at deterministic instants. These discontinuities induce, in turn and at the same instants, frequency discontinuities. The impact of the latter on the overall value of the failure frequency is important, but largely unknown and therefore not taken into account in the safety and reliability area, in spite of the fact that it generally induces optimistic estimation, if no compensatory action is planned. The presented method is based on the notion of ōcritical stateö and the use of advanced fault tree models (FT). The results obtained from these models are checked by using Monte Carlo simulation technique supported by equivalent Petri nets models (PN)
Range-separated double-hybrid density-functional theory applied to periodic systems
Sansone, Giuseppe; Usvyat, Denis; Toulouse, Julien; Sharkas, Kamal; Maschio, Lorenzo
Quantum chemistry methods exploiting density-functional approximations for short-range electron-electron interactions and second-order M{{\\o}}ller-Plesset (MP2) perturbation theory for long-range electron-electron interactions have been implemented for periodic systems using Gaussian-type basis functions and the local correlation framework. The performance of these range-separated double hybrids has been benchmarked on a significant set of systems including rare-gas, molecular, ionic, and covalent crystals. The use of spin-component-scaled MP2 for the long-range part has been tested as well. The results show that the value of $\\mu$ = 0.5 bohr^{--1} for the range-separation parameter usually used for molecular systems is also a reasonable choice for solids. Overall, these range-separated double hybrids provide a good accuracy for binding energies using basis sets of moderate sizes such as cc-pVDZ and aug-cc-pVDZ.
Time Evolution of Two-Level Systems Driven by Periodic Fields
Barata, J C A
In this paper we study the time evolution of a class of two-level systems driven by periodic fields in terms of new convergent perturbative expansions for the associated propagator U(t). The main virtue of these expansions is that they do not contain secular terms, leading to a very convenient method for quantitatively studying the long-time behaviour of that systems. We present a complete description of an algorithm to numerically compute the perturbative expansions. In particular, we applied the algorithm to study the case of an ac-dc field (monochromatic interaction), exploring various situations and showing results on (time-dependent) observable quantities, like transition probabilities. For a simple ac field, we analised particular situations where an approximate effect of dynamical localisation is exhibited by the driven system. The accuracy of our calculations was tested measuring the unitarity of the propagator U(t), resulting in very small deviations, even for very long times compared to the cycle of...
Interuser Interference Analysis for Direct-Sequence Spread-Spectrum Systems Part I: Partial-Period Cross-Correlation
Ni, Jianjun (David)
This presentation discusses an analysis approach to evaluate the interuser interference for Direct-Sequence Spread-Spectrum (DSSS) Systems for Space Network (SN) Users. Part I of this analysis shows that the correlation property of pseudo noise (PN) sequences is the critical factor which determines the interuser interference performance of the DSSS system. For non-standard DSSS systems in which PN sequence s period is much larger than one data symbol duration, it is the partial-period cross-correlation that determines the system performance. This study reveals through an example that a well-designed PN sequence set (e.g. Gold Sequence, in which the cross-correlation for a whole-period is well controlled) may have non-controlled partial-period cross-correlation which could cause severe interuser interference for a DSSS system. Since the analytical derivation of performance metric (bit error rate or signal-to-noise ratio) based on partial-period cross-correlation is prohibitive, the performance degradation due to partial-period cross-correlation will be evaluated using simulation in Part II of this analysis in the future.
An integrated multi?period planning of the production and transportation of multiple petroleum products in a single pipeline system
Directory of Open Access Journals (Sweden)
Alberto Herrßn
Full Text Available A multiproduct pipeline provides an economic way to transport large volumes of refined petroleum products over long distances. In such a pipeline, different products are pumped back?to?back without any separation device between them. The sequence and lengths of such pumping runs must be carefully selected in order to meet market demands while minimizing pipeline operational costs and satisfying several constraints. The production planning and scheduling of the products at the refinery must also be synchronized with the transportation in order to avoid the usage of the system at some peak?hour time intervals. In this paper, we propose a multi?period mixed integer nonlinear programming (MINLP model for an optimal planning and scheduling of the production and transportation of multiple petroleum products from a refinery plant connected to several depots through a single pipeline system. The objective of this work is to generalize the mixed integer linear programming (MILP formulation proposed by Cafaro and Cerdß (2004, Computers and Chemical Engineering where only a single planning period was considered and the production planning and scheduling was not part of the decision process. Numerical examples show how the use of a single period model for a given time period may lead to infeasible solutions when it is used for the upcoming periods. These examples also show how integrating production planning with the transportation and the use of a multi?period model may result in a cost saving compared to using a single?period model for each period, independently.
Solitons in PT-symmetric periodic systems with the quadratic nonlinearity
Moreira, F. C.; Konotop, V. V.; Malomed, B. A.
We introduce a one-dimensional system combining the PT-symmetric complex periodic potential and the ?(2) (second-harmonic-generating) nonlinearity. The imaginary part of the potential, which represents spatially separated and mutually balanced gain and loss, affects only the fundamental-frequency (FF) wave, while the real potential acts on the second-harmonic (SH) component too. Soliton modes are constructed, and their stability is investigated (by means of the linearization and direct simulations) in semi-infinite and finite gaps in the corresponding spectrum, starting from the bifurcation which generates the solitons from edges of the gapsÆ edges. Families of solitons embedded into the continuous spectrum of the SH component are found too, and it is demonstrated that a part of the families of these embedded solitons is stable. The analysis is focused on effects produced by the variation of the strength of the imaginary part of the potential, which is a specific characteristic of the PT system. The consideration is performed chiefly for the most relevant case of matched real potentials acting on the FF and SH components. The case of the real potential acting solely on the FF component is briefly considered too.
New dimensions of the periodic system: superheavy, superneutronic, superstrange, antimatter nuclei
Greiner, Walter
The possibilities for the extension of the periodic system into the islands of superheavy (SH) elements, to and beyond the neutron drip line and to the sectors of strangeness and antimatter are discussed. The multi-nucleon transfer processes in low-energy damped collisions of heavy actinide nuclei may help us to fill the gap between the nuclei produced in the "hot" fusion reactions and the continent of known nuclei. In these reactions we may also investigate the "island of stability". In many such collisions the lifetime of the composite giant system consisting of two touching nuclei turns out to be rather long (?10-20 s); sufficient for observing line structure in spontaneous positron emission from super-strong electric fields (vacuum decay), a fundamental QED process not observed yet experimentally. At the neutron-rich sector near the drip line islands and extended ridges of quasistable nuclei are predicted by HF calculations. Such nuclei, as well as very long living superheavy nuclei may be provided in double atomic bomb explosions. A tremendously rich scenario of new nuclear structure emerges with new magic numbers in the strangeness domain. Various production mechanisms are discussed for these objects and for antinuclei in high energy heavy-ion collisions.
Analysis of the ancient river system in Loulan period in Lop Nur region
Zhu, Jianfeng; Jia, Peng; Nie, Yueping
The Lop Nur region is located in the east of the Tarim Basin. It has served as the strategic passage and communication hub of the Silk Road since Han Dynasty. During Wei-Jin period, the river system there was well developed and the ancient city of Loulan was bred there. In this study, GIS is used to accomplish automatic extraction of the river course in the Lop Nur region at first using ArcGIS. Then the RCI index is constituted to extract ancient river course from Landsat ETM image with band 3 and band 4. It is concluded that the north river course of Peacock River conformed before the end of the 4th century AD according to the distribution of the entire river course of the Lop Nur region. Later, the Peacock River changed its way to south to Tarim River, and flowed into Lop Nur along the direction paralleling Altun Mountain from west to east. It was the change of the river system that mainly caused the decrease in water supply around ancient city of Loulan before the end of 4th century. The ancient city of Loulan has been gradually ruined in the sand because of the absence of water supply since then.
The profile of the epidermal growth factor system in rat endometrium during postpartum involution period.
Alan, Emel; Liman, Narin; Sa?s÷z, Hakan
The epidermal growth factor (EGF) plays a crucial role in the control of uterine cell proliferation, growth and differentiation. This study was designed to investigate the spatiotemporal expression pattern and localization of the EGF receptor/ligand system during the process of uterine involution using immunohistochemistry. Our results indicated that the expression of the ErbB/HER receptors and their ligands varied with structural changes in the uterus at different days of involution. Supranuclear punctate ErbB1 immunostaining was observed in the luminal and glandular epithelial cells and endometrial fibroblasts. Moderate ErbB2/HER2 immunoreactivity was observed in the lateral membrane and cytoplasm of the epithelial cells on the 1st, 3rd and 5th days and was decreased on the other days of involution. The amount of nuclear and cytoplasmic ErbB3/HER3 and ErbB4/HER4 immunostaining remained constant throughout the postpartum period. The EGF immunoreaction was weak in the luminal and glandular epithelium throughout the involution period. Although the cytoplasmic AREG immunoreactivity in the glandular epithelium was stronger on the 1st and 3rd days compared with the other days of involution, NRG1 immunostaining was weak on the 1st and 3rd days and was moderate in the apical cytoplasm on the 10th and 15th days of involution. The macrophages displayed strong cytoplasmic immunoreactivity for ErbB3/HER3, ErbB4/HER4, EGF, AREG and NRG. Strong, moderate and weak immunostaining for ErbB2/HER2, ErbB4/HER4 and other proteins (ErbB1, ErbB3, AREG and NRG), respectively, was present in the myometrial smooth muscle cells. These findings support the hypothesis that the EGFsystem plays a role in the development of various physiological changes associated with uterine involution. PMID:25754972
The Dynamics of known Short-period Multi-planet Systems in the Presence of Outer Planets
Granados Contreras, Agueda P.; Boley, Aaron C.
Among the Kepler planet candidate sample, 23% of stellar hosts contain multiple transiting planet candidates (Burke et al. 2014). The false positive rate among the multi-candidate systems is expected to be very low, suggesting that the candidates in these systems are truly planets. The large abundance of these systems suggests that the formation of multi-planet systems at short orbital periods (the candidate period distribution peaks between 10 and 20 days) is a fundamental mode of planet formation. However, we do not understand what processes lead to the diversity of planetary systems or whether the formation processes that give rise to Kepler multi-planet systems also permit the formation of distant planets akin to the Solar System. To this end, we explore the consequences that outer planets have on the stability and observability of known Kepler and Kepler-like multi-planet systems.
Evaluation of implementing a multi-user integrated case management system for undergraduate students during a clinical training period.
Tamagawa, H; Ojima, M; Tanaka, M; Shizukuishi, S
In this paper, we evaluate the efficiency of our multi-user system, which enables undergraduate students to now determine their progress in clinical requirements through their clinical training period. After implementing the system, instructors in each clinic can understand the progress or laziness of every student better than before. PMID:8591434
Searches for Periodic Neutrino Emission from Binary Systems with 22 and 40 Strings of IceCube
Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; B÷ser, S.; Botner, O.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; De Clercq, C.; Degner, T.; Demir÷rs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; DĒaz-Vķlez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; EngdegÕrd, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Gl³senkamp, T.; Goldschmidt, A.; Goodman, J. A.; G¾ra, D.; Grant, D.; Griesel, T.; Gro▀, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; H³l▀, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kenny, P.; Kiryluk, J.; Kislat, F.; Klein, S. R.; K÷hne, J.-H.; Kohnen, G.; Kolanoski, H.; K÷pke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; L³nemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mķszßros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pķrez de los Heros, C.; Petrovic, J.; Piegsa, A.; Pieloth, D.; Porrata, R.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Sch÷nwald, A.; Schukraft, A.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; St÷▀l, A.; Strahler, E. A.; Str÷m, R.; St³er, M.; Sullivan, G. W.; Swillens, Q.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration
In this paper, we present the results of searches for periodic neutrino emission from a catalog of binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. In the analysis, the period is fixed by these photon observations, while the phase and duration of the neutrino emission are treated as free parameters to be fit with the data. If the emission occurs during ~20% or less of the total period, this analysis achieves better sensitivity than a time-integrated analysis. We use the IceCube data taken from 2007 May 31 to 2008 April 5 with its 22 string configuration and from 2008 April 5 to 2009 May 20 with its 40 string configuration. No evidence for neutrino emission is found, with the strongest excess occurring for Cygnus X-3 at 2.1? significance after accounting for trials. Neutrino flux upper limits for both periodic and time-integrated emission are provided.
Quantum signature of a periodic orbit family in a Hamiltonian system
International Nuclear Information System (INIS)
We have computed the energy spectrum for a specific two dimensional anharmonic oscillator and compared the oscillations of the smoothed density of states with those predicted by semiclassical theory. These oscillations are found to be due to the periodic-orbit family with shortest period. We also verify that the ''scarred'' intensity profile for these orbits is not affected by the period-doubling bifurcation cascade that breaks up the surrounding tori. (author). 12 refs, 7 figs
Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data
Prsa, Andrej
Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. Eclipsing binary stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached binaries host low-mass (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary-to-primary light ratio regime of ~1-2% for the circumbinary host system Kepler-16. Semi-detached binaries are ideal targets to study the dynamical processes such as mass flow and accretion, and the associated thermal processes such as intensity variation due to distortion of the lobe-filling component and material inflow collisions with accretion disks. Overcontact binaries are very abundant, yet their evolution and radiative properties are poorly understood and conflicting theories exist to explain their population frequency and structure. In addition, we will measure eclipse timing variations for all program binaries that attest to the presence of perturbing third bodies (stellar and substellar!) or dynamical interaction between the components. By a dedicated, detailed, manual modeling of these sets of targets, we will be able to use Kepler's ultra-high precision photometry to a rewarding scientific end. Thanks to the unprecedented quality of Kepler data, this will be a highly focused effort that maximizes the scientific yield and the reliability of the results. Our team has ample experience dealing with Kepler data (PI Prsa serves as chair of the Eclipsing Binary Working Group in the Kepler Science Team), spectroscopic follow-up (Co-Is Mahadevan and Bender both have experience with radial velocity instrumentation and large spectroscopic surveys), and eclipsing binary modeling (PI Prsa and Co-I Devinney both have a long record of theoretical and computational development of modeling tools). The bulk of funding we are requesting is for two postdoctoral research fellows to conduct this work at 0.5 FTE/year each, for the total of 2 years.
The rate of convergence of new Lax¢Oleinik type operators for time-periodic positive definite Lagrangian systems
International Nuclear Information System (INIS)
Assume that the Aubry set of the time-periodic positive definite Lagrangian L consists of one hyperbolic 1-periodic orbit. We provide an upper bound estimate of the rate of convergence of the family of new Lax¢Oleinik type operators associated with L introduced by the authors in Wang and Yan (2012 Commun. Math. Phys. 309 663¢91). In addition, we construct an example where the Aubry set of a time-independent positive definite Lagrangian system consists of one hyperbolic periodic orbit and the rate of convergence of the Lax¢Oleinik semigroup cannot be better than O(1/t) as t ? +?
Variability of the Spin Period of the White Dwarf in the Magnetic Cataclysmic Binary System EX Hya
Andronov, Ivan L.; Breus, Vitalii V.
The observations of the two-periodic magnetic cataclysmic system EX Hya have been carried out, using the telescopes RC16 and TOA-150 of the Tzec Maun observatory. 6 nights of observations were obtained in 2010-2011 (alternatively changing filters VR). Also the databases of WASP, ASAS and AAVSO have been analyzed. Processing time series was carried out using the program MCV. We analyzed changes in the rotation period of the white dwarf, and based on our own and previously pub...
Energy Technology Data Exchange (ETDEWEB)
Baruteau, Clement; Papaloizou, John C. B., E-mail: email@example.com, E-mail: email@example.com [Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
The Kepler mission is dramatically increasing the number of planets known in multi-planetary systems. Many adjacent planets have orbital period ratios near resonant values, with a tendency to be larger than required for exact first-order mean-motion resonances. This feature has been shown to be a natural outcome of orbital circularization of resonant planetary pairs due to star-planet tidal interactions. However, this feature holds in multi-planetary systems with periods longer than 10 days, in which tidal circularization is unlikely to provide efficient divergent evolution of the planets' orbits to explain these orbital period ratios. Gravitational interactions between planets and their parent protoplanetary disk may instead provide efficient divergent evolution. For a planet pair embedded in a disk, we show that interactions between a planet and the wake of its companion can reverse convergent migration and significantly increase the period ratio from a near-resonant value. Divergent evolution due to wake-planet interactions is particularly efficient when at least one of the planets opens a partial gap around its orbit. This mechanism could help account for the diversity of period ratios in Kepler's multiple systems from super-Earth to sub-Jovian planets with periods greater than about 10 days. Diversity is also expected for pairs of planets massive enough to merge their gap. The efficiency of wake-planet interactions is then much reduced, but convergent migration may stall with a variety of period ratios depending on the density structure in the common gap. This is illustrated for the Kepler-46 system, for which we reproduce the period ratio of Kepler-46b and c.
Emergency Diesel Generation System Surveillance Test Policy Optimization Through Genetic Algorithms Using Non-Periodic Intervention Frequencies and Seasonal Constraints
International Nuclear Information System (INIS)
Nuclear standby safety systems must frequently, be submitted to periodic surveillance tests. The main reason is to detect, as soon as possible, the occurrence of unrevealed failure states. Such interventions may, however, affect the overall system availability due to component outages. Besides, as the components are demanded, deterioration by aging may occur, penalizing again the system performance. By these reasons, planning a good surveillance test policy implies in a trade-off between gains and overheads due to the surveillance test interventions. In order maximize the systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic tests scheme. The optimization problem becomes, however, more complex. Hence, the use of a powerful optimization technique, such as GAs, is required. Some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem. The Emergency Diesel Generation System (EDGS) of a Nuclear Power Plant (N-PP) is a good example for demonstrating the introduction of seasonal constraints in the optimization problem. This system is responstimization problem. This system is responsible for power supply during an external blackout. Therefore, it is desirable during periods of high blackout probability to maintain the system availability as high as possible. Previous applications have demonstrated the robustness and effectiveness of the methodology. However, no seasonal constraints have ever been imposed. This work aims at investigating the application of such methodology in the Angra-II Brazilian NPP EDGS surveillance test policy optimization, considering the blackout probability growth during summer, due to the electrical power demand increase. Here, the model used penalizes test interventions by a continuous modulating function, which depends on the instantaneous blackout probability. Results have demonstrated the ability of the method in adapting the surveillance tests policy to seasonal behaviors. The knowledge acquired by the GA during the searching process has lead to test schedules that drastically minimize the test interventions at periods of high blackout probability. It is compensated by more frequent tests redistributed through the periods of low blackout probability, in order to provide improvement on the overall average availability at the system level. (authors)
A Periodical Production Plan for Uncertain Orders in a Closed-Loop Supply Chain System
Directory of Open Access Journals (Sweden)
Hsiao-Fan Wang
Full Text Available Production planning is a major activity in the manufacturing or processing industries. A good plan helps the company lower its expenses, increase profit, or both. However, the worldwide economy is made up of closely related systems. Thus, a small change induces fluctuation in the supply chain. Although a production plan is based on the predicted demand, economic fluctuations make prediction difficult. Therefore, coping with production risksof uncertain demands heavily depends on the judgment and experience of the producer or customer. In addition, the reuse of recyclable products has become a major approach in reducing resource consumption because of environmental consciousness. Thus, a closed-loop supply chain has replaced the traditional supply chain to facilitate recycling, accommodate reprocess, ease environmental degradation, and save on resource costs. This study thus considers a production plan in a closed-loop supply chain, where periodic orders of retailers are adjusted and described byfuzzy quantities. The goal of the producer is to maximize profit while trying to satisfy these orders to the greatest extent. Fuzzy Set Theory is applied to construct a Fuzzy Chance-Constrained Production Mix Model (FCCPMM to enable the risk attitude of the decision maker to be adopted to address uncertainty.Theoretical evidence is supported by numerical illustration
ABCD Matrices as Similarity Transformations of Wigner Matrices and Periodic Systems in Optics
Baskal, S
The beam transfer matrix, often called the $ABCD$ matrix, is a two-by-two matrix with unit determinant, and with three independent parameters. It is noted that this matrix cannot always be diagonalized. It can however be brought by rotation to a matrix with equal diagonal elements. This equi-diagonal matrix can then be squeeze-transformed to a rotation, to a squeeze, or to one of the two shear matrices. It is noted that these one-parameter matrices constitute the basic elements of the Wigner's little group for space-time symmetries of elementary particles. Thus every $ABCD$ matrix can be written as a similarity transformation of one of the Wigner matrices, while the transformation matrix is a rotation preceded by a squeeze. This mathematical property enables us to compute scattering processes in periodic systems. Laser cavities and multilayer optics are discussed in detail. For both cases, it is shown possible to write the one-cycle transfer matrix as a similarity transformation of one of the Wigner matrices....
Multi-Layered Ring Log-Periodic Antennas Array Design for GPS Systems
Directory of Open Access Journals (Sweden)
M. Abri
Full Text Available The objective of the present study is the design of log periodic ring printed antennas array witch generates circular polarization with wide band by single feed linearly polarized elements for GPS systems. The radiating elements have been fed by magnetic coupling through a slot. The circular polarization is achieved by having a basic 2ū2 sub-arrays with unique element angular and phase arrangement, both the element angular orientation and feed phase are arranged in the 0░, 90░, 180 and 270░ fashion. The purpose of different angular orientations of the patches is to generate two orthogonally polarized fields, while -3dB coupler is used to provide the required amplitude and phase delays for circular polarization generation. This uniquely formed array has the capability of generating excellent circular polarization. An association of the coupler with the antennas has been established.This work is completed using the momentÆs method of Momentum software. Good performances of adaptation and polarization were obtained. The simulation results are then presented and discussed.
Upper gastrointestinal system bleeding treated by somatostatin analogue (ocreotide in the neonatal period: a case report
Directory of Open Access Journals (Sweden)
Afsin Kundak
Full Text Available In the neonatal period, upper gastrointestinal system (GIS bleeding may be due to benign disorders which do not require any treatments or may be relevant to serious conditions requiring urgent intervention. There are two major causes of upper GIS bleeding developed in the newborns; vitamin K deficiency-induced hemorrhagic disease of the newborn and maternal blood swallowed during birth. Other causes of this type of bleeding include gastritis, esophagitis, peptic ulcus (PU, coagulopathy, sepsis, vascular malformations, trauma, and esofageal-gastric duplications. Rarely, gastric erosion or perforation due to oro/naso gastric tube might cause severe upper GIS bleeding. Hemodynamic resuscitation, bleeding control, and prevention of the recurrence form the basis of the management. However, a somatostatin analogue (ocreotide may be helpful by reducing the splanchnic blood if bleeding is caused by a known vascular lesion or arterial erosion. In this paper, a case of newborn with upper GIS bleeding developed within the first 24 hour life and probably caused by arterial erosion due to oro/gastric tube and treated by ocreotide was presented in the light of literature.
Cogging effect minimization in PMSM position servo system using dual high-order periodic adaptive learning compensation.
Luo, Ying; Chen, Yangquan; Pi, Youguo
Cogging effect which can be treated as a type of position-dependent periodic disturbance, is a serious disadvantage of the permanent magnetic synchronous motor (PMSM). In this paper, based on a simulation system model of PMSM position servo control, the cogging force, viscous friction, and applied load in the real PMSM control system are considered and presented. A dual high-order periodic adaptive learning compensation (DHO-PALC) method is proposed to minimize the cogging effect on the PMSM position and velocity servo system. In this DHO-PALC scheme, more than one previous periods stored information of both the composite tracking error and the estimate of the cogging force is used for the control law updating. Asymptotical stability proof with the proposed DHO-PALC scheme is presented. Simulation is implemented on the PMSM servo system model to illustrate the proposed method. When the constant speed reference is applied, the DHO-PALC can achieve a faster learning convergence speed than the first-order periodic adaptive learning compensation (FO-PALC). Moreover, when the designed reference signal changes periodically, the proposed DHO-PALC can obtain not only faster convergence speed, but also much smaller final error bound than the FO-PALC. PMID:20605022
A dynamical systems analysis of the kinematics of time-periodic vortex shedding past a circular cylinder
Ottino, Julio M.
Computer flow simulation aided by dynamical systems analysis is used to investigate the kinematics of time-periodic vortex shedding past a two-dimensional circular cylinder in the context of the following general questions: (1) Is a dynamical systems viewpoint useful in the understanding of this and similar problems involving time-periodic shedding behind bluff bodies; and (2) Is it indeed possible, by adopting such a point of view, to complement previous analyses or to understand kinematical aspects of the vortex shedding process that somehow remained hidden in previous approaches. We argue that the answers to these questions are positive. Results are described.
Complex dynamics and switching transients in periodically forced Filippov prey¢predator system
International Nuclear Information System (INIS)
Highlights: ĢWe develop a Filippov prey¢predator model with periodic forcing. ĢThe sliding mode dynamics and its domain have been investigated. ĢThe existence and stability of sliding periodic solution have been discussed. ĢThe complex dynamics are addressed through bifurcation analyses. ĢSwitching transients and their biological implications have been discussed. - Abstract: By employing threshold policy control (TPC) in combination with the definition of integrated pest management (IPM), a Filippov prey¢predator model with periodic forcing has been proposed and studied, and the periodic forcing is affected by assuming a periodic variation in the intrinsic growth rate of the prey. This study aims to address how the periodic forcing and TPC affect the pest control. To do this, the sliding mode dynamics and sliding mode domain have been addressed firstly by using UtkinÆs equivalent control method, and then the existence and stability of sliding periodic solution are investigated. Furthermore, the complex dynamics including multiple attractors coexistence, period adding sequences and chaotic solutions with respect to bifurcation parameters of forcing amplitude and economic threshold (ET) have been investigated numerically in more detail. Finally the switching transients associated with pest outbreaks and their biological implications have been discussed. Our results indicate that the sliding periodic solution could be globally stable, and consequently the prey or pest population can be controlled such that its density falls below the economic injury level (EIL). Moreover, the switching transients have both advantages and disadvantages concerning pest control, and the magnitude and frequency of switching transients depend on the initial values of both populations, forcing amplitude and ET
Periodic orbit quantization of a weakly interacting two-body system using perturbed symmetry-broken trace formulas
International Nuclear Information System (INIS)
The semiclassical limit of the quantum few-body problem has not been studied in general terms from the point of view of periodic orbit theory. In a previous paper, we studied noninteracting two-body systems [Phys. Rev. A 62, 042109 (2000)] and discussed the fact that the periodic orbits occur in continuous families. Interactions destroy the periodic orbit families leaving a discrete set of isolated periodic orbits. In this paper, we consider the effect of weak two-body interactions, which can be thought of as symmetry-breaking perturbations and can thus be analyzed using a theory developed by Creagh [Ann. Phys. (N.Y.) 248, 1 (1996)]. The Poeschl-Teller two-body system confined in a square well is analyzed to illustrate the use of the formalism. It is shown that the effect of the interaction can be evaluated for all two-particle periodic orbits, and that the coarse-grained quantum density of states can be fully reproduced from simply summing the perturbed contributions of each periodic orbit family. Good numerical estimates of the quantum singlet energies can actually be obtained, but it is found that that perturbed trace formulas cannot reproduce the multiplet splittings predicted from quantum mechanics. Several interesting properties are observed depending on the range of the interaction and on whether the interaction is attractive or repulsive
A critical period for omega-3 nutritional supplementation in the development of the rodent visual system.
De Velasco, P C; Sandre, P C; Tavares Do Carmo, M G; Faria-Melibeu, A C; Campello-Costa, P; Ferraz, A C; Andrade Da Costa, B L S; Serfaty, C A
Retinocollicular connections form precise topographical maps that are normally completed through the selective elimination of misplaced axons and the stabilization of topographically ordered axon terminals during early development. Omega-3 fatty acids, acquired exclusively through the diet, and its main metabolite, docosahexaenoic acid (DHA), are involved in brain development and synaptic maturation. We have previously shown that the nutritional restriction of omega-3/DHA results in abnormal retinocollicular topographical fine-tuning. Therefore, we studied the role of omega-3 fatty acids nutritional supplementation and the developmental time windows during which this postnatal supplementation would restore normal topographical maps in the visual system. Female rats and their litters were chronically fed with either control (soy oil) or restricted omega-3 (coconut oil) diets. Fish oil supplementation was introduced between either postnatal day (PND) 7-13, PND7-28 or PND21-42. At PND13, PND28 or PND42, animals received an anterograde eye injection of a neuronal tracer to visualize retinocollicular axons. Confirming previous observations we found that an omega-3/DHA deficiency resulted in an abnormally high innervation density of retinal axons at the visual layers of the superior colliculus (SC). Although a short-term fish oil supplementation between PND7-13 could not restore normal retinocollicular topography, an extended treatment between PND7-28 completely recovered normal innervation densities of retinotectal axons. However, a late onset supplementation protocol, between PND28-42, was no longer effective in the restoration of the abnormal topographical pattern induced by an early omega-3 nutritional malnutrition. The results suggest a critical period for omega3/DHA dietary intake for the proper development of visual topographical maps. PMID:25916576
Critical experiments on an enriched uranium solution system containing periodically distributed strong thermal neutron absorbers
International Nuclear Information System (INIS)
A series of 62 critical and critical approach experiments were performed to evaluate a possible novel means of storing large volumes of fissile solution in a critically safe configuration. This study is intended to increase safety and economy through use of such a system in commercial plants which handle fissionable materials in liquid form. The fissile solution's concentration may equal or slightly exceed the minimum-critical-volume concentration; and experiments were performed for high-enriched uranium solution. Results should be generally applicable in a wide variety of plant situations. The method is called the 'Poisoned Tube Tank' because strong neutron absorbers (neutron poisons) are placed inside periodically spaced stainless steel tubes which separate absorber material from solution, keeping the former free of contamination. Eight absorbers are investigated. Both square and triangular pitched lattice patterns are studied. Ancillary topics which closely model typical plant situations are also reported. They include the effect of removing small bundles of absorbers as might occur during inspections in a production plant. Not taking the tank out of service for these inspections would be an economic advantage. Another ancillary topic studies the effect of the presence of a significant volume of unpoisoned solution close to the Poisoned Tube Tank on the critical height. A summary of the experimental findings is that boron compounds were excellent absorbers, as expected. This was true for granular materials such as Gerstley Borate and Borax; but it was also true for the flexible solid composed of boron carbide and rubber, even though only thin sheets were used. Experiments with small bundles of absorbers intentionally removed reveal that quite reasonable tanks could be constructed that would allow a few tubes at a time to be removed from the tank for inspection without removing the tank from production service
Operator-interactive surveillance method of periodic inspection of active engineered safety system of WWER 440 type reactors
International Nuclear Information System (INIS)
Functionally the engineered safety system (ESS) can be devided into two main parts: the emergency core cooling system and the pressure reduction system of hermetic rooms. Both parts consist of passive and active subsystems, their availability has periodically to be checked during the normal operation of the nuclear power plant. The passive sub-systems are checked during the annual shutdown period of the reactors when their reloading having been finished, the active subsystems may and have to be checked during the normal operation of the plant, too. This can be performed by the appropriate execution of the operating start-up instructions concerning these systems, while the effectiveness of their checking can be increased by computerized data processing. A simple method resulting satisfactory information for the operator to qualify the ESS is presented. (orig./HP)
The Method of Holomorphic Foliations in Planar Periodic Systems: The Case of Riccati Equations
?o?adek, Henryk
We develop a new method of investigation of periodic solutions of planar holomorphic polynomial differential equations with trigonometric coefficients. This method relies on analysis of geometry of leaves of certain holomorphic foliations in CP1ūCP1. We concentrate our attention on the case of Riccati equations. We determine the dynamics of the non-autonomous equations, using some local invariants of holomorphic vector fields defining the foliations. In particular, new examples of Riccati equations without periodic solutions are presented.
Period-3 catastrophe and enhanced diffusion in two-dimensional Hamiltonian systems
International Nuclear Information System (INIS)
Quantitative analysis of the period-3 catastrophe is developed for the standard map and for the stochastic heating map as illustrative examples of two-dimensional area preserving mappings. Analytic expression of the diffusion coefficient is derived for the stochastic heating, and compared to results of numerical observation. Here, as for the case of the standard map, the multi-periodic accelerator modes give rise to anomalous enhancement of the diffusion rate. (author)
Orbital period derivative of a binary system using an exact orbital energy equation
Zaveri, Vikram H.
It is proposed that the equations of motion in periodic relativity which yielded major predictions of general relativity without utilizing Riemannian geometry and geodesic trajectories are exact in nature and can be applied to pulsars and inspiraling compact binaries for analyzing orbital period derivative and two polarization gravitational wave forms. Exactness of these equations eliminates the need for higher order xPN corrections to the orbital energy part of the balance ...
Proof of the existence of wave operators for the hyperbolic systems with a potential periodic in time
International Nuclear Information System (INIS)
We prove the existence of the scattering operator for the wave equation with a potential which is periodic in time and has compact support in space, in dimension greater than or equal to 3, provided the energy is uniformly bounded. The key result is the decay of the local energy. The RAGE theorem of Georgiev and Petkov implies weak decay and we get strong convergence by using the compactness of the local evolution operator, derived from a microlocal analysis of the propagation of singularities. In the case where the dimension is odd, the decay is exponential for initial data: i) with compact support and ii) included in a subspace of finite codimension. We give some sufficient conditions for the boundedness of the energy by studying the spectrum of the local evolution operator. We extend these results to first order hermitian systems with arbitrary multiplicity and with a periodic potential such as the Dirac system in a periodic electromagnetic field
Optimal unit commitment of the power system in Bulgaria during the transitional period to power wholesale market
International Nuclear Information System (INIS)
The paper presents a procedure for optimal one year unit commitment in Bulgarian electric power system during the transitional period to wholesale market, combining certain classical theoretical models with heuristic methods. Comments are made on the transition from yearly commitment to weekly and daily dispatching control. The stages of the theory and practices for results optimality
Output-only modal analysis of linear time-periodic systems with application to wind turbine simulation data
DEFF Research Database (Denmark)
Allen, Matthew S.; Sracic, Michael W.
Many important systems, such as wind turbines, helicopters and turbomachinery, must be modeled with linear time-periodic equations of motion to correctly predict resonance phenomena. Time periodic effects in wind turbines might arise due to blade-to-blade manufacturing variations, stratification in the velocity of the wind with height and changes in the aerodynamics of the blades as they pass the tower. These effects may cause parametric resonance or other unexpected phenomena, so it is important to properly characterize them so that these machines can be designed to achieve high reliability, safety, and to produce economical power. This work presents a system identification methodology that can be used to identify models for linear, periodically time-varying systems when the input forces are unmeasured, broadband and random. The methodology is demonstrated for the well-known Mathieu oscillator and then used to interrogate simulated measurements from a rotating wind turbine. The measurements were simulated for a 5 MW turbine modeled in the HAWC2 simulation code, which includes both structural dynamic and aerodynamic effects. This simulated system identification provides insights into the test and measurement requirements and the potential pitfalls, and simulated experiments such as this may be useful to obtain a set of time-periodic equations of motion from a numerical model, since a closed form model is not readily available by other means due to the way in which the aeroelastic effects are treated in the simulation code.
Optimal base-stock policy for the inventory system with periodic review, backorders and sequential lead times
DEFF Research Database (Denmark)
Johansen, Sžren Glud; Thorstenson, Anders
We extend well-known formulae for the optimal base stock of the inventory system with continuous review and constant lead time to the case with periodic review and stochastic, sequential lead times. Our extension uses the notion of the 'extended lead time'. The derived performance measures are exact for Poisson demands.
Note: Optimal base-stock policy for the inventory system with periodic review, backorders and sequential lead times
DEFF Research Database (Denmark)
Johansen, Sžren Glud; Thorstenson, Anders
We show that well-known textbook formulae for determining the optimal base stock of the inventory system with continuous review and constant lead time can easily be extended to the case with periodic review and stochastic, sequential lead times. The provided performance measures and conditions for optimality are exact.
Tunable wideband bandstop acoustic filter based on 2D multi-physical phenomena periodic systems
Romero-GarcĒa, V; Garcia-Raffi, L M
The physical properties of a periodic distribution of absorbent resonators is used in this work to design a tunable wideband bandstop acoustic filter. Analytical and numerical simulations as well as experimental validations show that the control of the resonances and the absorption of the scatterers along with their periodic arrangement in air introduces high technological possibilities to control noise. Sound manipulation is perhaps the most obvious application of the structures presented in this work. We apply this methodology to develop a device as an alternative to the conventional acoustic barriers with several properties from the acoustical point of view but also with additional aesthetic and constructive characteristics.
A New Framework For Helicopter Vibration Suppression; Time-Periodic System Identification and Controller Design
Ulker, Fatma Demet
In forward flight, helicopter rotor blades function within a highly complex aerodynamic environment that includes both near-blade and far-blade aerodynamic phenomena. These aerodynamic phenomena cause fluctuating aerodynamic loads on the rotor blades. These loads when coupled with the dynamic characteristics and elastic motion of the blade create excessive amount of vibration. These vibrations degrade helicopter performance, passenger comfort and contributes to high cost maintenance problems. In an effort to suppress helicopter vibration, recent studies have developed active control strategies using active pitch links, flaps, twist actuation and higher harmonic control of the swash plate. In active helicopter vibration control, designing a controller in a computationally efficient way requires accurate reduced-order models of complex helicopter aeroelasticity. In previous studies, controllers were designed using aeroelastic models that were obtained by coupling independently reduced aerodynamic and structural dynamic models. Unfortunately, these controllers could not satisfy stability and performance criteria when implemented in high-fidelity computer simulations or real-time experiments. In this thesis, we present a novel approach that provides accurate time-periodic reduced-order models and time-periodic H2 and H infinity controllers that satisfy the stability and performance criteria. Computational efficiency and the necessity of using the approach were validated by implementing an actively controlled flap strategy. In this proposed approach, the reduced-order models were directly identified from high-fidelity coupled aeroelastic analysis by using the time-periodic subspace identification method. Time-periodic H2 and Hinfinity controllers that update the control actuation at every time step were designed. The control synthesis problem was solved using Linear Matrix Inequality and periodic Riccati Equation based formulations, for which an in-house periodic Riccati solver was developed. The results show that first, important helicopter aeroelastic features can only be captured using high-fidelity coupled aeroelastic analysis; ignoring these features through uncoupled analysis leads to closed-loop performance degradation and instabilities. Second, time-periodic models are necessary to obtain an accurate map between control actuation and helicopter aeroelastic response; time-invariant models fail to provide accurate prediction. Third, time-Periodic H2 and H infinity controllers satisfy the stability and design performance criteria when implemented in high-fidelity aeroelastic analysis. Finally, we propose robust H2 and Hinfinity controller design strategies that are capable of modeling variable advance ratios.
76 FR 12300 - Safety Management System for Certificated Airports; Extension of Comment Period
...10-14] RIN 2120-AJ38 Safety Management System for Certificated Airports...certificate holder to establish a safety management system (SMS) for its entire...No. 10-14, entitled ``Safety Management System for Certificated...
75 FR 76928 - Safety Management System for Certificated Airports; Extension of Comment Period
...10-14] RIN 2120-AJ38 Safety Management System for Certificated Airports...certificate holder to establish a safety management system (SMS) for its entire...No. 10-14, entitled ``Safety Management System for Certificated...
76 FR 5296 - Safety Management System for Part 121 Certificate Holders; Extension of Comment Period
...10-15] RIN 2120-AJ86 Safety Management System for Part 121 Certificate...121 to develop and implement a safety management system (SMS) to improve its...No. 10-15, entitled ``Safety Management Systems for Part 121...
Sistemas de tutoramento e ķpocas de transplante de physalis Periods replanting and training systems of cape-gooseberry
Directory of Open Access Journals (Sweden)
Clßudia Simone Madruga Lima
Full Text Available A physalis (Physalis peruviana ķ uma pequena fruta com grandes potencialidades, que, associadas ao seu ciclo curto e Ós propriedades nutracĻuticas, apresenta possibilidade de alto retorno econ¶mico. O objetivo deste trabalho foi avaliar o sistema de tutoramento e a ķpoca de transplante mais adequados para o crescimento e a produńŃo de frutos de P. peruviana nas condiń§es edafoclimßticas do sul do Rio Grande do Sul. O trabalho foi desenvolvido em Pelotas, RS, na safra de 2007/2008. O transplante de mudas de physalis foi realizado em duas ķpocas (ķpoca 1, 21/11/2007 e ķpoca 2 15/01/2008, sendo as plantas tutoradas em quatro sistemas de conduńŃo (sistema "V" invertido, sistema triangular, sistema vertical com bambu e sistema vertical com fitilho, semelhantes aos utilizados na cultura do tomateiro. O delineamento experimental adotado foi de blocos casualizados, com trĻs repetiń§es, sendo cada um representado por dez plantas. Os tratamentos formaram um fatorial 2x4 (ķpocas de transplante x sistemas de tutoramento. As varißveis analisadas foram: incremento do comprimento e da ßrea da seńŃo do ramo principal, ßrea da seńŃo do ramo principal, produtividade e eficiĻncia produtiva. Foi evidenciado que a primeira ķpoca de transplante associada aos sistemas de tutoramento "V" invertido e triangular proporciona melhor desempenho agron¶mico das plantas de physalis.The cape-gooseberry (Physalis peruviana is a small fruit with great potentialities that whether associated to its short cycle and nutraceutical properties it shows high economical return. The work aimed to evaluate the best training system and replant period to plant growth, production and fruit quality of P. peruviana under edaphoclimatic at conditions of southern Rio Grande do Sul. The trial was carried out in Pelotas, RS, in 2007/2008 crop. Transplanting seedlings cape-gooseberry was conducted in two seasons Plant replanting was done in two periods (period 1, 21/11/2007 and period 2, 15/01/2008. Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord, similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.
Sistemas de tutoramento e ķpocas de transplante de physalis / Periods replanting and training systems of cape-gooseberry
Scientific Electronic Library Online (English)
Clßudia Simone Madruga, Lima; Michel Aldrighi, Gonńalves; Zeni Fonseca Pinto, Tomaz; Andrea De Rossi, Rufato; Josķ Carlos, Fachinello.
Full Text Available A physalis (Physalis peruviana) ķ uma pequena fruta com grandes potencialidades, que, associadas ao seu ciclo curto e Ós propriedades nutracĻuticas, apresenta possibilidade de alto retorno econ¶mico. O objetivo deste trabalho foi avaliar o sistema de tutoramento e a ķpoca de transplante mais adequad [...] os para o crescimento e a produńŃo de frutos de P. peruviana nas condiń§es edafoclimßticas do sul do Rio Grande do Sul. O trabalho foi desenvolvido em Pelotas, RS, na safra de 2007/2008. O transplante de mudas de physalis foi realizado em duas ķpocas (ķpoca 1, 21/11/2007 e ķpoca 2 15/01/2008), sendo as plantas tutoradas em quatro sistemas de conduńŃo (sistema "V" invertido, sistema triangular, sistema vertical com bambu e sistema vertical com fitilho), semelhantes aos utilizados na cultura do tomateiro. O delineamento experimental adotado foi de blocos casualizados, com trĻs repetiń§es, sendo cada um representado por dez plantas. Os tratamentos formaram um fatorial 2x4 (ķpocas de transplante x sistemas de tutoramento). As varißveis analisadas foram: incremento do comprimento e da ßrea da seńŃo do ramo principal, ßrea da seńŃo do ramo principal, produtividade e eficiĻncia produtiva. Foi evidenciado que a primeira ķpoca de transplante associada aos sistemas de tutoramento "V" invertido e triangular proporciona melhor desempenho agron¶mico das plantas de physalis. Abstract in english The cape-gooseberry (Physalis peruviana) is a small fruit with great potentialities that whether associated to its short cycle and nutraceutical properties it shows high economical return. The work aimed to evaluate the best training system and replant period to plant growth, production and fruit qu [...] ality of P. peruviana under edaphoclimatic at conditions of southern Rio Grande do Sul. The trial was carried out in Pelotas, RS, in 2007/2008 crop. Transplanting seedlings cape-gooseberry was conducted in two seasons Plant replanting was done in two periods (period 1, 21/11/2007 and period 2, 15/01/2008). Plants were trained under four systems (inverted "V" system, triangular system, vertical system using bamboo or vertical system using polypropylene cord), similarly to the tomato culture. Experimental design adopted was a complete randomized block in a 2x4 factorial (replant period x training system) with three replications of ten plants each. The variables analyzed were: increment of length and section area of the main branch, section area of the main branch, yield and yield efficiency. It was evidenced that the first period of replant associated to the training systems inverted "V" and triangular improved the agronomical performance of cape-gooseberry plants.
Mendeleev-2013. VII All-Russian conference of young scientists, postgraduate students and students with international participation on chemistry and nanomaterials. Book of abstracts. Section 5. Physical chemistry
International Nuclear Information System (INIS)
VII All-Russian conference of young scientists, postgraduate students and students with international participation on chemistry and nanomaterials was conducted on the Chemistry department of Saint-Petersburg State University on April, 2-5, 2013. In the conference participants from 14 countries took part. There were five sections: Nanochemistry and nanomaterials, Analytic chemistry, Inorganic chemistry, Organic chemistry, Physical chemistry. In the collection (Section 5 - Physical chemistry) there are abstracts concerning the investigations of physico-chemical properties and structure of various materials: composites on the base of polymers and fullerenes, as well as catalysts, ion-exchange membranes, sorbents etc.; phase studies of different systems, rare earth elements among them; development of physico-chemical determination methods of biological active compounds, and many other problems
Relationship between different types of stability for linear almost periodic systems in Banach spaces
Cheban, David N.
For the linear equation $x'= A(t)x$ with recurrent (almost periodic) coefficients in an arbitrary Banach space, we prove that the asymptotic stability of the null solution and of all limit equations implies the uniform stability of the null solution.
Nonlinear stability of periodic traveling wave solutions of systems of viscous conservation laws in the generic case
Johnson, Mathew A.; Zumbrun, Kevin
Extending previous results of Oh-Zumbrun and Johnson-Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions. Key to our analysis is a nonlinear cancellation estimate observed by Johnson and Zumbrun, along with a detailed understanding of the Whitham averaged system. The latter motivates a careful analysis of the Bloch perturbation expansion near zero frequency and suggests factoring out an appropriate translational modulation of the underlying wave, allowing us to derive the sharpened low-frequency estimates needed to close the nonlinear iteration arguments.
Methods of topological degree theory in Malkin I. G. - Melnikov V. K.'s problems for periodically perturbed systems
Makarenkov, Oleg
A topological degree based averaging principle has been proposed by J. Mawhin in his PhD thesis [J. Mawhin, Le Probleme des Solutions Periodiques en Mecanique non Lineaire, These de doctorat en sciences, Universite de Liege, 1969]. In his thesis the author gives analogous topological degree versions of classical bifurcation results due to I.G. Malkin and V.K. Melnikov, namely the conditions for bifurcation of periodic solutions from families are expressed in term of the topological degree of the bifurcation function. Moreover, the topological index of bifurcated periodic solutions is evaluated over that degree. A third part of the thesis is devoted to the rate the bifurcated periodic solutions converge when the perturbation vanishes. The differentiability of perturbed systems is not assumed.
Directory of Open Access Journals (Sweden)
Constanta ENEA
Full Text Available Since the formation of the United Principalities (24/01/1859, Romania has undergone a series of profound, permanent reforms of its fundamental institutions. The international context had an influence important, often enteritis in shaping its institutions, including the system of taxes. We plan to make a brief review of taxation in modern Romania, starting from the formation of the United Principalities (1859 via the international recognition of Romania as a kingdom (1881, the formation of the National Unitary (1918 international recognition (1919 - 1921, the interwar period (1918-1939, the Second world War (1939-1945 suffered territorial losses in 1940 , the communist period (1945-1989, the post-communist period (1989-2006, will deepen in a future article pre and post EU accession in terms of fiscal and customs.
Dynamic Stability Analysis of Periodically Time-Varying Rotor System with a Transverse Crack
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Costin D. Untaroiu
Full Text Available Fatigue cracks may appear in horizontal rotating machinery due to periodic stresses imposed to its shaft. The investigation of stability behavior of cracked rotors can lead to proper diagnosis of machinery and to prevent possible accidents caused by the rotor failure. In this study, the dynamic stability of a rotor with a transverse crack is investigated. Models of both open and breathing cracks are developed and then used in the model of a cracked Jeffcot (de Laval rotor. The stability of rotor motion equations represented by differential equations with periodic coefficients is investigated using Floquet theory. While both crack models show instability regions around the first un-damped frequency, sub-harmonic regions are predicted by the breathing crack models. Compared to perturbation methods frequently used to determine the stability regions, the transition matrix approach used in this study can be applied to complex models of rotors and consequently may help in the identification of cracks in rotating machinery.
Peer attachment formation by systemic redox regulation with social training after a sensitive period
Mamiko Koshiba; Genta Karino; Aya Senoo; Koki Mimura; Yuka Shirakawa; Yuta Fukushima; Saya Obara; Hitomi Sekihara; Shimpei Ozawa; Kentaro Ikegami; Toyotoshi Ueda; Hideo Yamanouchi; Shun Nakamura
Attachment formation is the most pivotal factor for humans and animals in the growth and development of social relationships. However, the developmental processes of attachment formation mediated by sensory-motor, emotional, and cognitive integration remain obscure. Here we developed an animal model to understand the types of social interactions that lead to peer-social attachment formation. We found that the social interaction in a sensitive period was essential to stabilise or overwrite the...
Orbital period derivative of a binary system using an exact orbital energy equation
Zaveri, Vikram H
It is proposed that the equations of motion that yielded two major predictions of general relativity without utilizing Riemannian geometry and geodesic trajectories are exact in nature and can be applied to pulsars and inspiralling compact binaries for analyzing orbital period derivative and two polarization gravitational wave forms. Exactness of these equations eliminates the need for higher order xPN corrections to the orbital energy part of the balance equation.
Coulomb interactions at quantum Hall critical points of systems in a periodic potential
Ye, Jinwu; Sachdev, Subir
We study the consequences of long-range Coulomb interactions at the critical points between integer/fractional quantum Hall states and an insulator. We use low energy theories for such transitions in anyon gases in the presence of an external periodic potential. We find that Coulomb interactions are marginally irrelevant for the integer quantum Hall case. For the fractional case, depending upon the anyon statistics parameter, we find behavior similar to the integer case, or ...
Progress report of the CEC project Rodos system development. Period: 1 september 92-31 august 93
International Nuclear Information System (INIS)
Within the context of the Radioprotection program of the CEC, the RODOS project (Real-time On-line DecisiOn Support system) aims at the development of a decision support system for nuclear emergencies. RODOS involves 22 research teams, divided in 4 sub-projects: 'Meteorology and Atmospheric Dispersion, 'System Development', 'Decision Aiding Techniques'. The fourth sub-project is a Joint Study Project of the Agreement between CEC ad the CIS republics. EDF is working in the 'System Development' sub-project and namely in the 'training' group. This group aims at the creation of a specific training course for health physics managers, based on RODOS. This note reproduces the progress report of the 'Development System' project. The reporting period is: September 92 - August 93. Progress bas been made within the reporting period in the: - development of data assimilation methods incorporating both monitoring data and model predictions for obtaining consistent pictures of the environmental contamination and the source term ; - improvement and extension of the modules ATSTEP-CORA (atmospheric dispersion and deposition), EMERSIM (simulation of emergency actions), ECOAMOR (exposure pathways and dose calculation) and FRODO (simulation of relocation and agricultural countermeasures) ; - preparation of training courses using RODOS as illustrative tool ; - extension of the functions of the RODOS operating system OSY, in particular of RoGIS, its geographical information system. (author). 2 figs
The existence of periodic orbits and invariant tori for some 3-dimensional quadratic systems.
Jiang, Yanan; Han, Maoan; Xiao, Dongmei
We use the normal form theory, averaging method, and integral manifold theorem to study the existence of limit cycles in Lotka-Volterra systems and the existence of invariant tori in quadratic systems in ?(3). PMID:24982980
Resolution of the identity atomic orbital Laplace transformed second order M°ller-Plesset theory for nonconducting periodic systems.
Izmaylov, Artur F; Scuseria, Gustavo E
An improvement in performance of the atomic orbital Laplace transformed second-order M°ller-Plesset (AO-LT-MP2) method for periodic systems is reported using the resolution of identity (RI) technique. Transformation of the two-electron integrals constitutes the main computational bottleneck of the AO-LT-MP2 method. A substitution of regular four-center integrals by their three center counterparts in the RI approximation naturally reduces the computational cost of the integral transformation step. The RI divergence problem in the presence of periodic boundary conditions is solved in our implementation by restricting the fitting domain. Accuracy and computational efficiency of the RI-AO-LT-MP2 approach are assessed on a set of one-dimensional test systems: trans-polyacetylene and anti-transoid polymethineimine. PMID:18535725
Light curve solutions and study of roles of magnetic fields in period variations of the UV Leo system
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D Manzoori
Full Text Available The solutions of photometric BV light curves for the Algol like system UV Leo were obtained using Wilson-Devinney code. The physical and orbital parameters along with absolute dimensions of the system were determined. It has been found that to best fit the V light curve of the system, assumptions of three dark spots were necessary two on the secondary and one on the primary. The absolute visual magnitudes (Mv of the individual components i.e., primary and secondary were estimated to 4.41 and 4.43, respectively, through the color curve analysis. The period analysis of the system presented elsewhere, indicated a cyclic period change of 12 yr duration, which was attributed to magnetic activity cycle, as a main cause of period variation in the system, through the Applegate mechanism. To verify the Applegate model I preformed calculations of some related parameters barrowed from Apllegate and Kalimeris. Values of all the calculated parameters were in accordance to those obtained for similar systems by Applegate. The differential magnitudes ? B and ? V, along with corresponding values of ?(B-V color index. The cyclic variations in brightness are quite clear. There are three predictions of Applegate's theory concerning effects of cyclic magnetic changes on the period variations, which can be checked through the observations, these are as follows: I The long term variations in mean brightness (at outside of eclipses and cyclic changes of orbital period, vary with the same period. II The active star gets bluer as it gets brightened and/or the brightness and color variations are to be in phase. III Changes in luminosity due to changes in quadrupole moment should be of the order 0.1 mag. All the above mentioned predictions of ApplegateÆs theory are verified. These results combined with cyclic character of P(E presented elsewhere and also consistency of parameters which are obtained in this paper, led me to conclude that one the main causes of period variability in UV Leo system is magnetic activity cycle (newly presented here. Since both components (G0&G2 of this system magnetically can be active, and separation of the components is relatively low (3.9Rs, the magnetic braking could also cause the period change. The magnetized star winds move outward from the star, but are twisted due to rapid rotation of star. Charged particles in the stars wind become trapped in the star's magnetic field and are dragged along the field lines .The result is angular momentum (AM transfer from the star by magnetic field to the charged particles. As the winds leave the star surface they are dragged by the magnetic field which in turn slows down the star's rotation.
Analytic construction of periodic orbits about the collinear points. [in sun-earth system for ISEE-3 mission
Richardson, D. L.
A third-order analytical solution for halo-type periodic motion about the collinear points of the circular-restricted problem is presented. The three-dimensional equations of motion are obtained by a Lagrangian formulation. The solution is constructed using the method of successive approximations in conjunction with a technique similar to the Lindstedt-Poincare method. The theory is applied to the sun-earth system.
A periodic inspection and replacement policy for systems subject to competing failure modes due to degradation and traumatic events
Huynh, Khac Tuan; Barros, Anne; Berenguer, Christophe; Castro, Inma
This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to ...
Periodic orbits and 10 cases of unbounded dynamics for one Hamiltonian system defined by the conformally coupled field
Starkov, Konstantin E.
In this paper we study invariant domains with unbounded dynamics for one cosmological Hamiltonian system which is formed by the conformally coupled field; this system was introduced by Maciejewski et al. (2007). We find a few groups of conditions imposed on parameters of this system for which all trajectories are unbounded in both of time directions. Further, we present a few groups of other conditions imposed on system parameters under which we localize the invariant domain with unbounded dynamics; this domain is defined with help of bounds for values of the Hamiltonian level surface parameter. We describe one group of conditions when our system possesses two periodic orbits found explicitly. In some of rest cases we get localization bounds for compact invariant sets.
The Earth-Moon system during the Late Heavy Bombardment period
Jorgensen, Uffe Graae; Appel, Peter W. U.; Hatsukawa, Yuichi; Frei, Robert; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi
The Late Heavy Bombardment (LHB) period is the narrow time interval between 3.8 and 3.9 Gyr ago, where the bulk of the craters we see on the Moon formed. Even more craters formed on the Earth. During a field expedition to the 3.8 Gyr old Isua greenstone belt in Greenland, we sampled three types of metasedimentary rocks, that contain direct traces of the LHB impactors by a seven times enrichment (150 ppt) in iridium compared to present day ocean crust (20 ppt). We show...
Quasi-Periodic Post-Critical Response Types of a Harmonically Excited Auto-Parametric System.
Czech Academy of Sciences Publication Activity Database
Nßprstek, Ji?Ē; Fischer, Cyril
Kippen : Civil-Comp Press, 2011 - (B.H.V. Topping; Y. Tsompanakis), s. 1-26 ISBN 978-1-905088-46-1. ISSN 1759-3433. [International Conference on Civil, Structural and Environmental Engineering Computing /13./. Chania (GR), 06.09.2011-09.09.2011] R&D Projects: GA AV ?R(CZ) IAA200710805; GA ?R(CZ) GA103/09/0094; GA AV ?R(CZ) IAA200710902 Institutional research plan: CEZ:AV0Z20710524 Keywords : non-linear vibration * quasi-periodic response * spherical pendulum Subject RIV: JM - Building Engineering http://dx.doi.org/10.4203/ccp.96.77
Optimization of Water Circulation Period for the Culture of Goldfish with Spinach in Aquaponic System
A. P. Shete; Verma, A K; R. S. Tandel; Chandra Prakash; Tiwari, V.K.; Tanveer Hussain
Experiment with varied water circulation periods having 4, 8, 12, and 24 hrs/day as T1, T2, T3 and T4, respectively in aquaponics, evaluated against a control (without aquaponics) revealed higher fish and plant growth in T3 and T4. The mean growth of fish varied significantly among treatments showing higher growth in T4 and control followed by T3, T2 and T1. Survival rate was 100% in all the treatments as well as control. Percentage weight gain, SGR (% day-1) also showed the similar trend as ...
Taking into account period variations and actuators saturation in sampled-data systems
Seuret, Alexandre; Gomes Da Silva, Joa?o Manoel
This paper deals with the problem of stability and stabilization of sampled-data systems under asynchronous samplings and actuators saturation. The method is based, on the first hand, on the use of a novel class of Lyapunov functionals whose derivative is negative along the trajectories of the continuous-time model of the sampled data system. It is shown that this fact guarantees that a quadratic Lyapunov function is strictly decreasing for the discrete-time asynchronous system. On the other ...
Sub-daily periodic radon signals in a confined radon system.
Steinitz, G; Piatibratova, O; Kotlarsky, P
Signals from radon in air enclosed in a tight canister are recorded by five gamma detectors located around the horizontal plane and along the vertical axis. At steady state conditions (diffusion inputĀ=Āradon decay) the primary variation is of daily radon (DR) signals with amplitudes of around 20-25%. The DR signal, with a rounded form, is characterized by periodicities of 24-, 12- and 8-h (i.e. 1, 2 & 3 CPD). Similar DR variation patterns occur in the east and west sensors whereas inverse DR patterns are recorded by the north and south sensors. Short term (ST) signals, having saw tooth form and periods of 2-3Āh (frequencies in the range of 9-12 CPD) are observed at all five sensors and are superimposed on the DR signals with relative amplitudes of around 20%. They exhibit differing forms and phase at the different sensors, located at different directions around the canister. The latter is similar to the spatial manifestation of form and phase of the DR signal in such experiments, indicating a communality of the driving mechanism. At this stage a geophysical explanation cannot be presented for the ST signals. In this respect a peculiar observation is that their extraordinary occurrence coincides in time with the Tohoku Earthquake (MwĀ=Ā9.0; 11 March 2011). PMID:24704767
On Asymptotic Stability of Solutions to Nonlinear Systems of Differential Equations with Periodic Coefficients
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Gennadii Demidenko
Full Text Available This paper is devoted to the study of a nonlinear system of differential equations with two parameters. We determine values of the parameters under which solutions to the system are asymptotically stable. We obtain also estimates enabling us to indicate the decay rate of solutions at infinity.
The Formative Period of Listen Look Learn, a Multi-Media Communication Skills System.
Heflin, Virginia A.; And Others
A 2-year study was conducted in 1965-67 for the following purposes: (1) to evaluate the materials and techniques of a new beginning reading program, Listen Look Learn (LLL) Multi-Media Communication Skills System, in order to make revisions where necessary and (2) to compare the LLL system in its formative stage with that of basal reader programs.ģ
Quasi-gradient systems, modulational dichotomies, and stability of spatially periodic patterns
Pogan, Alin; Zumbrun, Kevin
Extending the approach of Grillakis-Shatah-Strauss, Bronski-Johnson-Kapitula, and others for Hamiltonian systems, we explore relations between the constrained variational problem $\\min_{X:C(X)=c_0} \\mathcal{E}(X)$, $c_0\\in \\RM^r$, and stability of solutions of a class of degenerate "quasi-gradient" systems $dX/dt=-M(X)\
The short-period non-contact binary systems UU Lyn and GR Tau
International Nuclear Information System (INIS)
Two binary systems UU Lyn and GR Tau are discussed on the basis of BV photoelectric observations and spectroscopic observations which were made between 1980 and 1981 at the Tokyo Astronomical Observatory. The component stars in both systems are found to be still inside their Roche lobes but very close to them. (Auth.)
Directory of Open Access Journals (Sweden)
Ram Kishan
Full Text Available This paper deals with the stochastic analysis of a complex system with correlatedworking and rest time of repairman. The system consists of two subsystems, say A and Bconnected in series. Subsystem A consists of two identical units whereas subsystem B consists ofonly one unit. The operation of only one unit of subsystem A with subsystem B is sufficient to dothe job. The failure time distributions of the units are taken exponential while the repair timedistributions are assumed to be general. Various measures of system effectiveness useful tosystem managers are obtained by using regerative point technique. Graphical study of the systemthrough MTSF and profit function is also carried out.
Periodic pattern formation in reaction-diffusion systems: an introduction for numerical simulation.
Miura, T.; Maini, Pk
The aim of the present review is to provide a comprehensive explanation of Turing reaction-diffusion systems in sufficient detail to allow readers to perform numerical calculations themselves. The reaction-diffusion model is widely studied in the field of mathematical biology, serves as a powerful paradigm model for self-organization and is beginning to be applied to actual experimental systems in developmental biology. Despite the increase in current interest, the model is not well understoo...
Microwave periodic structures based on MicroElectroMechanical Systems (MEMS) and micromachining techniques
Perruisseau-carrier, Julien
As a result of the ever growing number of functionalities and standards to be supported by communication systems, as well as the constant development of radar and imaging technologies, a key research area in the field of microwaves and millimeter waves is the achievement of reconfigurability capabilities. In recent years, the progress of MicroElectroMechanical Systems (MEMS) fabrication techniques has allowed radically challenging the performances of reconfigurable devices based on establishe...
The Langevin Hull: Constant pressure and temperature dynamics for non-periodic systems
Vardeman, Charles F.; Stocker, Kelsey M.; Gezelter, J. Daniel
We have developed a new isobaric-isothermal (NPT) algorithm which applies an external pressure to the facets comprising the convex hull surrounding the system. A Langevin thermostat is also applied to the facets to mimic contact with an external heat bath. This new method, the ōLangevin Hullö, can handle heterogeneous mixtures of materials with different compressibilities. These systems are problematic for traditional affine transform methods. The Langevin Hull does not suffer from the ed...
Quasi-periodic propagation in time of some classical/quantum systems: Nielsen's conserved quantity and Floquet properties
Energy Technology Data Exchange (ETDEWEB)
Kramer, P [Theoretische Physik, University Tuebingen (Germany); Kramer, T [Institute for Theoretical Physics, University Regensburg (Germany); Man' ko, V I [Lebedev Physical Institute, Moscow (Russian Federation)], E-mail: firstname.lastname@example.com
We consider classical and quantum propagators for two different time intervals. If these propagators follow one another in a Fibonacci sequence we get a discrete quasi-periodic system. A theorem due to Nielsen provides a novel conserved quantity for this system. The Nielsen quantity controls the transition between commutative and non-commutative propagation in time. The quasi-periodically kicked oscillator, moreover, is dominated by quasi-periodic analogues of the Floquet theorem.
Analysis of reactor coolant pump transient performance in primary coolant system during start-up period
International Nuclear Information System (INIS)
Highlights: ? Relationships between pump heads and the parameters of a system are established. ? Relationships between pump torques and the parameters of a system are established. ? The variables are non-dimensionlized in order to design a new system and pump. ? All variables are solved analytically. Pump characteristics are not required. ? Mechanism of reactor coolant pump start-up is mathematically solved and clarified. - Abstract: The reactor coolant pump is ōthe heartö of a nuclear reactor and the only high-speed revolving equipment in a pressurized water reactor primary cooling loop system. The accurate prediction of flow and pump transient performance, during start-up transients, is a very important factor in the reactor coolant pumps design and the nuclear reactor design. Based on the momentum conservation equation of the primary coolant and the moment balance relation of the reactor coolant pump, the transient pump total head, the acceleration head and the overcoming friction head during a pump start up are derived. The relationship between the above heads and the parameters of the system fluid and pump is established too. Furthermore, the transient torques during a pump start-up are also derived. They include the torques required to accelerate the coolant fluid, to accelerate the pump rotating parts and to overcome friction of coolant fluid in the pipes system. The relation between the above three transient torques and the parameters of the coolant fluid and the pump is respectively established. In addition, the above variables are all non-dimensionlized in order to design a new system. The transient flow rate and pump speed are solved analytically. The detailed information of the centrifugal pump characteristics is not required. The analytical non-dimensional flow rate, the pump speed, heads and torques are all affected by an energy ratio ?. The effects of ? on the three transient heads and the three transient torques are discussed respectively. A comparison with TsukamotoÆs experimental results, during the pump start-up, shows an excellent agreement
Assessment of periodic sub-diurnal Earth rotation variations at tidal frequencies through transformation of VLBI normal equation systems
Artz, Thomas; Tesmer Nķe B÷ckmann, Sarah; Nothnagel, Axel
We present an empirical model for periodic variations of diurnal and sub-diurnal Earth rotation parameters (ERPs) that was derived based on the transformation of normal equation (NEQ) systems of Very Long Baseline Interferometry (VLBI) observing sessions. NEQ systems that contain highly resolved polar motion and UT1-TAI with a temporal resolution of 15 min were generated and then transformed to the coefficients of the tidal ERP model to be solved for. To investigate the quality of this model, comparisons with empirical models from the Global Positioning System (GPS), another VLBI model and the model adopted by the conventions of the International Earth Rotation and Reference Systems Service (IERS) were performed. The absolute coefficients of these models agree almost completely within 7.5 ? as in polar motion and 0.5 ? s in UT1-TAI. Several bigger differences exist, which are discussed in this paper. To be able to compare the model estimates with results of the continuous VLBI campaigns, where signals with periods of 8 and 6 h were detected, terms in the ter- and quarter-diurnal band were included in the tidal ERP model. Unfortunately, almost no common features with the results of continuous VLBI campaigns or ERP predictions in these tidal bands can be seen.
Application of the Vibration Analysis of Linear Systems with Time-Periodic Coefficients to the Dynamics of a Rolling Tyre
In this article, theories of rolling tyre vibrations are presented. In previous publications, tread pattern was neglected and authors have studied vibrations in smooth tyres. When heterogeneity caused by a tread pattern on the tyre belt is introduced, it is shown that vibrations can be described by linear equations with time periodic coefficients. Firstly, the perturbation method is applied for a nearly smooth tyre, and the ōself-excitationö phenomenon, a general feature in time periodic linear systems, is illustrated with the semi-analytic expressions obtained. Then, the generalization to a strong heterogeneity is achieved using the Bloch wave theory. This theoretical background suggests the decomposition of experimental data of noise in time signals for a given phase as compared to the wheel rotation. Finally, an effective method for numerical computations of vibrations is proposed; it uses the Floquet theory, a consequence of the Bloch theory. Finite element formulation and algorithm are derived for the heterogeneous ōcircular ring modelö.
IUPAC Periodic Table of Isotopes for the Educational Community
International Nuclear Information System (INIS)
John Dalton first proposed the concept of atomic weights of the elements in the first decade of the nineteenth century. These atomic weights of the chemical elements were thought of as constants of nature, similar to the speed of light. Dmitri Mendeleev arranged the atomic weights of the elements in ascending order of value and used the systematic variation of their chemical properties to produce his Periodic Table of the Elements in 1869. Measurement of atomic weight values became an important chemical activity for a century and a half. Theodore Richards received a Noble Prize for his work in this area. In 1913, Fredrick Soddy found a species of radium, which had an atomic weight value of 228, compared to the familiar radium gas value of 226. Soddy coined the term 'isotope' (Greek for 'in the same place') to account for this second atomic weight value in the radium position of the Periodic Table. Both of these isotopes of radium are radioactive. Radioactive isotopes are energetically unstable and will decay (disintegrate) over time. The time it takes for one half of a sample of a given radioactive isotope to decay is the half-life of that isotope. In addition to having different atomic weight values, radium-226 and radium-228 also have different half-life values. Around the same time as Soddy's work, J.J. Thomson (discoverer of the electron) identified two stable (non-radioactive) isotopes of the same element, neon. Over the next 40 years, the majority of the known cnext 40 years, the majority of the known chemical elements were found to have two or more stable (or long-lived radioactive isotopes that contribute significantly to the determination of the atomic weights of the elements).
IUPAC Periodic Table of Isotopes for the Educational Community
Energy Technology Data Exchange (ETDEWEB)
Holden N. E.; Holden,N.E.; Coplen,T.B.
John Dalton first proposed the concept of atomic weights of the elements in the first decade of the nineteenth century. These atomic weights of the chemical elements were thought of as constants of nature, similar to the speed of light. Dmitri Mendeleev arranged the atomic weights of the elements in ascending order of value and used the systematic variation of their chemical properties to produce his Periodic Table of the Elements in 1869. Measurement of atomic weight values became an important chemical activity for a century and a half. Theodore Richards received a Noble Prize for his work in this area. In 1913, Fredrick Soddy found a species of radium, which had an atomic weight value of 228, compared to the familiar radium gas value of 226. Soddy coined the term 'isotope' (Greek for 'in the same place') to account for this second atomic weight value in the radium position of the Periodic Table. Both of these isotopes of radium are radioactive. Radioactive isotopes are energetically unstable and will decay (disintegrate) over time. The time it takes for one half of a sample of a given radioactive isotope to decay is the half-life of that isotope. In addition to having different atomic weight values, radium-226 and radium-228 also have different half-life values. Around the same time as Soddy's work, J.J. Thomson (discoverer of the electron) identified two stable (non-radioactive) isotopes of the same element, neon. Over the next 40 years, the majority of the known chemical elements were found to have two or more stable (or long-lived radioactive isotopes that contribute significantly to the determination of the atomic weights of the elements).
Fuel Cell/Battery Powered Bus System. Final Report for period August 1987 - December 31, 1997
Energy Technology Data Exchange (ETDEWEB)
Wimmer, R.
Today, fuel cell systems are getting much attention from the automotive industry as a future replacement for the internal combustion engine (ICE). Every US automobile manufacturer and most foreign firms have major programs underway to develop fuel cell engines for transportation. The objective of this program was to investigate the feasibility of using fuel cells as an alternative to the ICE. Three such vehicles (30-foot buses) were introduced beginning in 1994. Extensive development and operational testing of fuel cell systems as a vehicle power source has been accomplished under this program. The development activity investigated total systems configuration and effectiveness for vehicle operations. Operational testing included vehicle performance testing, road operations, and extensive dynamometer emissions testing.
Bott periodicity for Z2 symmetric ground states of gapped free-fermion systems
Kennedy, Ricardo
Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools rather than K-theory. Key to our proof is a natural transformation that squares to the standard Bott map and relates the ground state of a d-dimensional system in symmetry class s to the ground state of a (d+1)-dimensional system in symmetry class s+1. This relation gives a new vantage point on topological insulators and superconductors.
The Earth-Moon system during the Late Heavy Bombardment period
Jorgensen, Uffe Graae; Hatsukawa, Yuichi; Frei, Robert; Oshima, Masumi; Toh, Yosuke; Kimura, Atsushi
The Late Heavy Bombardment (LHB) period is the narrow time interval between 3.8 and 3.9 Gyr ago, where the bulk of the craters we see on the Moon formed. Even more craters formed on the Earth. During a field expedition to the 3.8 Gyr old Isua greenstone belt in Greenland, we sampled three types of metasedimentary rocks, that contain direct traces of the LHB impactors by a seven times enrichment (150 ppt) in iridium compared to present day ocean crust (20 ppt). We show that this enrichment is in agreement with the lunar cratering rate, providing the impactors were comets, but not if they were asteroids. Our study is a first direct indication of the nature of the LHB impactors, and the first to find an agreement between the LHB lunar cratering rate and the Earth's early geochemical record (and the corresponding lunar record). The LHB comets that delivered the iridium we see at Isua will at the same time have delivered the equivalent of a km deep ocean, and we explain why one should expect a cometary ocean to be...
Double scale expansion of periodic solutions of some vibrating systems, with non linear springs
Brahim, Nadia Ben
We consider small solutions of a system with smooth non-linearities for which we provide an approximate solution by using double scale technique; a rigorous proof of convergence of the double scale method is included; for the forced response, a stability result is needed in order to prove convergence in a neighborhood of a primary resonance.
40 CFR 75.24 - Out-of-control periods and adjustment for system bias.
...adjustment for system bias. (a) If an out-of-control...shall take corrective action and repeat the tests applicable...such that it passes the bias test or calculate and use the bias adjustment factor as...appropriate corrective actions according to...
Interfacial chemistry in solvent extraction systems: Progress report for period April 1, 1986-March 31, 1987
International Nuclear Information System (INIS)
Proton magnetic resonance spectroscopic, vapor pressure osmometric and Karl Fischer titrimetric measurements have provided support for our earlier findings obtained from interfacial tension and mass transfer experiments that reversed micelles are formed, under certain conditions, in the system HDEHP/n-hexane/CaCl2 solution. These studies were further extended to include different organophosphorus acid (PC 88A), diluent (benzene), and metal ions (Co2+, Ni2+, and Zn2+) to determine whether reversed micellization is a general phenomenon occurring in solvent extraction systems which employ organophosphorus acids. The data obtained so far, suggest that reversed micellization indeed is a general phenomenon operative in organophosphorus acid extractant systems. A new mass transfer cell has been constructed in order to investigate the metal distribution equilibria and extraction kinetics of Co, Ni and Zn using atomic absorption spectrophotometric technique. A quasi-elastic light-scattering apparatus has been installed to investigate aggregation phenomena in solvent extraction systems. Preliminary drop-interface coalescence studies were performed, and the results were correlated with those obtained from interfacial tension measurements. The laser heterodyne light-scattering apparatus for measurement of interfacial viscoelastic properties also has been set-up and is being optimized for high resolution measurements. 21 refs., 16 figs
Singularity Structure Analysis of the Higher-Dimensional Time-Gated Manakov System: Periodic Excitations and Elastic Scattering
International Nuclear Information System (INIS)
We investigate the singularity structure analysis of the higher-dimensional time-gated Manakov system referring to the (2+1)-dimensional coupled nonlinear Schroedinger (CNLS) equations, and we show that these equations are Painleve-integrable. By means of the Weiss et al.'s methodology, we show the arbitrariness of the expansion coefficients and the consistency of the truncation corresponding to a special Baecklund transformation (BT) of these CNLS equations. In the wake of such transformation, following the Hirota's formalism, we derive a one-soliton solution. Besides, by using the Zakharov-Shabat (ZS) scheme which provides a general Lax-representation of an evolution system, we show that the (2+1)-dimensional CNLS system under interests is completely integrable. Furthermore, using the arbitrariness of the above coefficients, we unearth and investigate a typical spectrum of periodic coherent structures while depicting elastic interactions amongst such patterns. (author)
Directory of Open Access Journals (Sweden)
Full Text Available The techniques of carp culture are highly diversified, ranging from the extensive production in pond or open water with no fertilization or supplemental feeding to highly intensive systems in concrete tanks or cages. Among the different carp species, common carp is the best species reared in intensive monoculture, the others (Chinese and Indian carps being usually cultivated in polyculture (P. Kestemont, 1995. An experiment was conducted in inside recirculation system conditions to identify the technological performances on carp growth and survival at the Fishing and Aquaculture Department, Galati, during winter period (February, 2007 ¢ March, 2007. The 1-year-old carp (Cyprinus carpio 4792g; 4594 g; 4561 g and 4525 g (total weight grew to 7384g; 7017g; 6924g and 7125 g in 44 days in aquarium 1, 2, 3 and 4, respectively. In all aquariums, the fish appeared healthy and no mortality was observed. Feed conversion efficiencies (FCE had similar values among all aquariums, the highest FCE being found in B4 aquarium with 1, 57 value. Water quality parameters were acceptable range for fish culture. Results show that the carp rearing during winter period in the inside recirculation system is a very good economic solution.
A periodic Energy Decomposition Analysis (pEDA) method for the Investigation of Chemical Bonding in Extended Systems
Raupach, Marc
The development and first applications of a new periodic energy decomposition analysis (pEDA) scheme for extended systems based on the Kohn-Sham approach to density functional theory are described. The pEDA decomposes the binding energy between two fragments (e.g. the adsorption energy of a molecule on a surface) into several well-defined terms: preparation, electrostatic and dispersion interaction, Pauli repulsion and orbital relaxation energies. The pEDA presented here for an AO-based implementation can handle restricted and unrestricted fragments for 0D to 3D systems considering periodic boundary conditions with and without the determination of fragment occupations. For the latter case, reciprocal space sampling is enabled. The new method gives comparable results to established schemes for molecular systems and shows good convergence with respect to the basis set (TZ2P), the integration accuracy and k-space sampling. Four typical bonding scenarios for surface adsorbate complexes were chosen to highlight th...
The hematopoietic system of the acute radiation syndrome reconvalescents in post-accidental period
International Nuclear Information System (INIS)
The state of hemopoietic system has been studied since 1986 up to now in 145 patients who had acute radiation sickness after the Chernobyl accident. We studied clinical, morpho functional, histological, ultrastructural, biophysical, cultural, cytochemical indexes of the hematopoietic elements. The connection between hemopoietic microenvironment and hemopoiesis state was put up. The realization of the hematological disorders as myelodysplastic syndrome testified the most important problem in future
Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system
Battista, Emmanuele; Agnello, Simone; Esposito, Giampiero; Simo, Jules
Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess ...
Real-time Scheduling of periodic tasks in a monoprocessor system with a rechargeable battery
Chetto, Maryline; El Ghor, Hussein
We are interested in a real-time computing system that is powered through a rechargeable battery. In this context, two constraints need to be addressed: energy and deadlines. Classical task scheduling, in particular Earliest Deadline First, only accounts for timing parameters of the tasks and conse- quently is not suitable when considering energy constraints. We show here how to modify Earliest Deadline so as to account for the properties of the energy source, capacity of the energy storage a...
Time dependent unavailability analysis of nuclear safety systems considering periodically tested components
International Nuclear Information System (INIS)
It is of utmost importance to have a computer code in order to analyze how different parameters (like test duration time) affect the unavailability of safety systems of nuclear. In this context, a study was performed in order to evaluate the model employed by the FRANTIC computer code, which performs detailed calculations on the contribution to the system unavailability originated by hardware failures, component tests and repairs, aiming at considering the influence of different test schemes on the system unavailability. It was shown, by means of the results attained that the numerical model used by the FRANTIC code and the analytical model proposed by APOSTOLAKIS and CHU (4) give unavailability values much similar when the component tests are supposed to be perfect. When a test is supposed to be imperfect (that is, when it may induce a test is supposed to be imperfect (that is, when it may induce a failure on the component being tested), the analytical model presents more conservative results. (author)
Dynamics of self-excited thermoacoustic instability in a combustion system: Pseudo-periodic and high-dimensional nature
Okuno, Yuta; Small, Michael; Gotoda, Hiroshi
We have examined the dynamics of self-excited thermoacoustic instability in a fundamentally and practically important gas-turbine model combustion system on the basis of complex network approaches. We have incorporated sophisticated complex networks consisting of cycle networks and phase space networks, neither of which has been considered in the areas of combustion physics and science. Pseudo-periodicity and high-dimensionality exist in the dynamics of thermoacoustic instability, including the possible presence of a clear power-law distribution and small-world-like nature.
Periodic Review Probabilistic Multi-Item Inventory System with Zero Lead Time under Constraints and Varying Order Cost
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Hala A. Fergany
Full Text Available This study treats the probabilistic safety stock n-items inventory system having varying order cost and zero lead-time subject to two linear constraints. The expected total cost is composed of three components: the average purchase cost; the expected order cost and the expected holding cost. The policy variables in this model are the number of periods Nr* and the optimal maximum inventory level Qmr* and the minimum expected total cost. We can obtain the optimal values of these policy variables by using the geometric programming approach. A special case is deduced and an illustrative numerical example is added.
Ultrashort-period main-sequence eclipsing systems: new observations and light-curve solutions of six NSVS binaries
Dimitrov, Dinko P.; Kjurkchieva, Diana P.
We carried out photometric and low-resolution spectral observations of six eclipsing ultrashort-period binaries with main-sequence (MS)components. The light-curve solutions of the Rozhen observations show that all targets are overcontact systems. We found a well-defined empirical relation between period and semi-major axis for the short-period binaries and used it for estimation of the global parameters of the targets. Our results revealed that NSVS 925605 is quite an interesting target: (i) it is one of a few contact binaries with M components; (ii) it exhibits high activity (emission in the H? line, X-ray emission, large cool spots, non-Planck energy distribution); (iii) its components differ in temperature by 700 K. All the appearances of high magnetic activity and the huge fill-out factor (0.7) of NSVS 925605 may be a precursor of the predicted merging of close magnetic binaries. Another unusual binary is NSVS 2700153, which reveals considerable long-term variability.
Los Alamos plutonium facility applied systems integration project status report for period ending August 31, 1981
International Nuclear Information System (INIS)
The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports
Los Alamos plutonium facility applied systems integration project status report for period ending August 31, 1981
Energy Technology Data Exchange (ETDEWEB)
Shirk, D.G.; Bearse, R.C.; Marshall, R.S.; Baker, A.L.; Thomas, C.C. Jr.
The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports.
Contributions to a methodology for periodical verification of the parameters of the control systems at Cernavoda Nuclear plant Unit 1
International Nuclear Information System (INIS)
A model identification methodology for periodical verification of the regulating system parameters at Cernavoda NPP Unit 1 was developed. As support to this methodology, the computer program MODELIDENT was implemented in the Java programming language. This program is used for off-line evaluation of the real regulating systems characteristic parameters using an identification algorithm which takes as input data the system response collected for different input excitation signals, a structurally similar model of the analyzed regulating system, and some starting guess value of the unknown parameters. The real values of the parameters are determined during MODELIDENT program execution by applying an iterative algorithm and afterwards are retained as nominal reference values. The success of the identification algorithm is strongly dependent on how appropriately the structure of model's transfer function is chosen. By repeating periodically the identification method, using newly collected data from the process, the current value of the parameters are determined. Any deviations of the new values relative to the nominal reference values are interpreted as de-calibration of the control equipment and in this case corrective maintenance actions have to be taken. With the implementation of the presented methodology at Cernavoda NPP Unit 1 we can make the statement that the preventive maintenance activity is gaining a predictive feature, which can lead to the elimination of major hich can lead to the elimination of major degradation possibilities in the performances of the RS equipment and consequently to increase the NPP availability. On the basis of the experience gained in the practical application of the presented methodology we expect that the identification method will also have beneficial effects in the optimal control of the process systems and also in the activity of Full Scope Simulator software maintenance (the reference values of the identified parameters being used for fine tuning of the simulation models. (authors)
Interfacial chemistry in solvent extraction systems: Progress report for period April 1, 1985-March 31, 1988
International Nuclear Information System (INIS)
Interfacial behavior of extractant molecules and their interaction with metal ions has been investigated. Consideration was also given to the question of microscopic interfaces, i.e., those associated with reversed micelles as well as microemulsions. NMR spectroscopy, fluorescence spectroscopy, quasi-elastic light scattering, vapor pressure osmometry, and Karl-Fischer titrimetry provided support for findings obtained from interfacial tension experiments that reversed micelles are formed, under certain conditions, in the system di(2-ethylhexyl)phosphoric acid (HDEHP)/ n-hexane/CaCl2 solution. These techniques were further extended to include different organophosphorus acids (PC 88A and CYANEX 272), diluent (benzene), and metal ions (Co2+, Ni2+, and Zn2+) to determine whether reversed micellization occurs in solvent extraction systems which employ organophosphorus acids. A preliminary general model of the aggregation mechanism for metal-extractant complexes has been proposed. Also various laser techniques have been used to investigate the structure and dynamics of extractant films. A laser fluorescence apparatus for probing interfacial dynamics is under construction. 64 refs., 29 figs
A Practical Approach to Improve Optical Channel Utilization Period for Hybrid FSO/RF Systems
Directory of Open Access Journals (Sweden)
Ahmet Akbulut
Full Text Available In hybrid FSO/RF systems, mostly a hard switching mechanism is preferred in case of the FSO signal level falls below to the predefined threshold. In this work, a computationally simple approach is proposed to increase the utilization of the FSO channels bandwidth advantage. For the channel, clear air conditions have been supposed with the atmospheric turbulence. In this approach, FSO bit rate is adaptively changed to achieve desired BER performance. An IM/DD modulation, OOK (NRZ format has been used to show the benefit of the proposed method. Furthermore, to be more realistic with respect to the atmospheric turbulence variations within a day, some experimental observations have been followed up.
Mitral restenosis in the early postoperative period of a patient with systemic lupus erythematosus
Scientific Electronic Library Online (English)
Pablo Maria Alberto, Pomerantzeff; Jeanne D' Arc Hon¾ria, CorrĻa; Carlos Manuel de Almeida, BrandŃo; Raimunda Violante Campos de, Assis; Adib Domingos, Jatene.
Full Text Available A forty eight year old woman, who had undergone mitral comissurotomy and subsequently developed early restenosis, presented with major comissural fusion and verrucous lesions on the cuspid edges of the mitral valve, with normal subvalvar apparatus. Patient did well for the first six months after sur [...] gery when she began to present dyspnea on light exertion. A clinical diagnosis of restenosis was made, which was confirmed by an echocardiogram and cardiac catheterization. She underwent surgery, and a stenotic mitral valve with verrucous lesions suggesting Libman-Sacks' endocarditis was found. Because the diagnosis of systemic lupus erythematosus (SLE) had not been confirmed at that time, a bovine pericardium bioprosthesis (FISICS-INCOR) was implanted. The patient did well in the late follow-up and is now in NYHA Class I .
Mitral restenosis in the early postoperative period of a patient with systemic lupus erythematosus
Directory of Open Access Journals (Sweden)
Pomerantzeff Pablo Maria Alberto
Full Text Available A forty eight year old woman, who had undergone mitral comissurotomy and subsequently developed early restenosis, presented with major comissural fusion and verrucous lesions on the cuspid edges of the mitral valve, with normal subvalvar apparatus. Patient did well for the first six months after surgery when she began to present dyspnea on light exertion. A clinical diagnosis of restenosis was made, which was confirmed by an echocardiogram and cardiac catheterization. She underwent surgery, and a stenotic mitral valve with verrucous lesions suggesting Libman-Sacks' endocarditis was found. Because the diagnosis of systemic lupus erythematosus (SLE had not been confirmed at that time, a bovine pericardium bioprosthesis (FISICS-INCOR was implanted. The patient did well in the late follow-up and is now in NYHA Class I .
Comparison of the Newtonian and relativistic predicted trajectories for a low-speed periodically delta-kicked system
Lan, Boon Leong
The dynamics of a periodically delta-kicked Hamiltonian system moving at low speed (i.e., at speed much less than the speed of light) is studied numerically. In particular, the trajectory of the system predicted by Newtonian mechanics is compared with the trajectory predicted by special relativistic mechanics for the same parameters and initial conditions. We find that the Newtonian trajectory, although close to the relativistic trajectory for some time, eventually disagrees completely with the relativistic trajectory, regardless of the nature (chaotic, nonchaotic) of each trajectory. However, the agreement breaks down very fast if either the Newtonian or relativistic trajectory is chaotic, but very much slower if both the Newtonian and relativistic trajectories are nonchaotic. In the former chaotic case, the difference between the Newtonian and relativistic values for both position and momentum grows, on average, exponentially. In the latter nonchaotic case, the difference grows much slower, for example, linearly on average.
Study of short-period RS Canum Venaticorum and W Ursae Majoris binary systems: The global nature of H?
International Nuclear Information System (INIS)
I present the rotation versus emission characteristics of the H? line for several short-period (P-5) and the Rossby number (the ratio between the rotational period and the convective time scale) is seen for those components showing emission. Such a correlation suggests that the H? line is a good diagnostic for the study of the magnetic-related activity in late-type stellar systems. Plotting the L/sub Halpha//L/sub bol/ against a measure of the tidal amplitude of Scharlemann shows that the activity of the W UMa secondary components may be shut off by the tidal forces of the primaries. The shut-off appears in those components having a tidal amplitude > or approx. =0.02. It is, however, unclear whether the tidal damping of the diffe whether the tidal damping of the differential rotation is the sole mechanism responsible for the shut-off of the H? emission, as the activity damping may also be attributable to the contact nature of the W UMa systems
Investor's requirements on software of operating diagnostic system in period of nuclear power unit start-up
International Nuclear Information System (INIS)
The demands are summed up on the software for the diagnostic system of the Dukovany nuclear power plant in the period of the integrated hydraulic trial, the physical and power start-up of the unit. These demands have followed from experience gained with the first and second units of the plant which showed that it was very difficult to locate, using the installed diagnostic system, the source of the failure by analyzing an arbitrary signal from the sensor output. The functions are defined which the diagnostic system software must fulfil during the start-up when it is necessary to detect defects of delivered components including defects of assembly such as to allow their removal during the revision of the installation. Special attention is devoted to the identification of loose parts in the primary circuit and to the possibility of calibrating and simulating the system of loose parts in operation. The software of the system must proceed from an estimate of weight and kinetic energy of the loose part which must be identified, including the distance between the point of impact and the sensor, and the time of contact of the part with the point of impact. (Z.M.)
Finite Elements for a Beam System With Nonlinear Contact Under Periodic Excitation
Hazim, Hamad
Solar arrays are structures which are connected to satellites; during launch, they are in a folded position and submitted to high vibrations. In order to save mass, the flexibility of the panels is not negligible and they may strike each other; this may damage the structure. To prevent this, rubber snubbers are mounted at well chosen points of the structure; a prestress is applied to the snubber; but it is quite difficult to check the amount of prestress and the snubber may act only on one side; they will be modeled as one sided springs (see figure 2). In this article, some analysis for responses (displacements) in both time and frequency domains for a clamped-clamped Euler-Bernoulli beam model with a spring are presented. This spring can be unilateral or bilateral fixed at a point. The mounting (beam +spring) is fixed on a rigid support which has a sinusoidal motion of constant frequency. The system is also studied in the frequency domain by sweeping frequencies between two fixed values, in order to save the...
Existence of lattice solutions to semilinear elliptic systems with periodic potential
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Nicholas D. Alikakos
Full Text Available Under the assumption that the potential W is invariant under a general discrete reflection group $G'=TG$ acting on $mathbb{R}^n$, we establish existence of G'-equivariant solutions to $Delta u - W_u(u = 0$, and find an estimate. By taking the size of the cell of the lattice in space domain to infinity, we obtain that these solutions converge to G-equivariant solutions connecting the minima of the potential W along certain directions at infinity. When particularized to the nonlinear harmonic oscillator $u''+alpha sin u=0$, $alpha>0$, the solutions correspond to those in the phase plane above and below the heteroclinic connections, while the G-equivariant solutions captured in the limit correspond to the heteroclinic connections themselves. Our main tool is the G'-positivity of the parabolic semigroup associated with the elliptic system which requires only the hypothesis of symmetry for W. The constructed solutions are positive in the sense that as maps from $mathbb{R}^n$ into itself leave the closure of the fundamental alcove (region invariant.
Occupational external irradiation according to the control system data for the period 1984-1988
International Nuclear Information System (INIS)
The dose load to subjects working with radiation sources in Bulgaria was analysed on the basis of data obtained from the Centralized System for Individual Dosimetric Control. Personnel film- and thermoluminenscent dosimetry had been used for monitoring of about 8000 persons including 66% medical personnel (54% of them practicians, 12% - researchers), 28% industrial personnel, 6% - working in the science/education sphere. The external irradiation is prevailing. The average annual equivalent doses (AAED) by branches were: medicine 0.6 - 0.9 mSv/a, industry 1.3 - 3.1 mSCv/a, science/education 1.0 - 1.2 mSv/a. The most badly loaded contingent (? 5 mSv/a) were the gamma-defectoscopists, which represent one third of the group of industrial workers. The irradiation levels in X-ray and radioisotope diagnosis are low. Similar are also the conclusions derived from the comparison of the weighted average annual equivalent doses (WAAED): medicine 0.85 mSv/a; industry 2.3 mSv/a; science/education 1.1 mSv/a. Higher than the average one for respective areas is the irradiation in gamma-defectoscopy, radiotherapy and services for electromedical equipment. The WAAED for the contingent in this study was 1.3 mSv/a, and 95% of AAED received were lower than 5 mSv/a. The low probability of irradiation with doses higher than 50 mSv/a in medicine and industry was established. 2 tabs., 2 figs., 6 refs
A Fortran 90 Hartree-Fock program for one-dimensional periodic ?-conjugated systems using Pariser-Parr-Pople model
Kondayya, Gundra; Shukla, Alok
Pariser-Parr-Pople (P-P-P) model Hamiltonian is employed frequently to study the electronic structure and optical properties of ?-conjugated systems. In this paper we describe a Fortran 90 computer program which uses the P-P-P model Hamiltonian to solve the Hartree-Fock (HF) equation for infinitely long, one-dimensional, periodic, ?-electron systems. The code is capable of computing the band structure, as also the linear optical absorption spectrum, by using the tight-binding and the HF methods. Furthermore, using our program the user can solve the HF equation in the presence of a finite external electric field, thereby, allowing the simulation of gated systems. We apply our code to compute various properties of polymers such as trans-polyacetylene, poly- para-phenylene, and armchair and zigzag graphene nanoribbons, in the infinite length limit. Program summaryProgram title: ppp_bulk.x Catalogue identifier: AEKW_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 87 464 No. of bytes in distributed program, including test data, etc.: 2 046 933 Distribution format: tar.gz Programming language: Fortran 90 Computer: PCs and workstations Operating system: Linux, Code was developed and tested on various recent versions of 64-bit Fedora including Fedora 14 (kernel version 22.214.171.124-90). Classification: 7.3 External routines: This program needs to link with LAPACK/BLAS libraries compiled with the same compiler as the program. For the Intel Fortran Compiler we used the ACML library version 4.4.0, while for the gfortran compiler we used the libraries supplied with the Fedora distribution. Nature of problem: The electronic structure of one-dimensional periodic ?-conjugated systems is an intense area of research at present because of the tremendous interest in the physics of conjugated polymers and graphene nanoribbons. The computer program described in this paper provides an efficient way of solving the Hartree-Fock equations for such systems within the P-P-P model. In addition to the Bloch orbitals, band structure, and the density of states, the program can also compute quantities such as the linear absorption spectrum, and the electro-absorption spectrum of these systems. Solution method: For a one-dimensional periodic ?-conjugated system lying in the xy-plane, the single-particle Bloch orbitals are expressed as linear combinations of p-orbitals of individual atoms. Then using various parameters defining the P-P-P Hamiltonian, the Hartree-Fock equations are set up as a matrix eigenvalue problem in the k-space. Thereby, its solutions are obtained in a self-consistent manner, using the iterative diagonalizing technique at several k points. The band structure and the corresponding Bloch orbitals thus obtained are used to perform a variety of calculations such as the density of states, linear optical absorption spectrum, electro-absorption spectrum, etc. Running time: Most of the examples provided take only a few seconds to run. For a large system, however, depending on the system size, the run time may be a few minutes to a few hours.
Investigation of periodic multilayers
Bodnarchuck, V.; Cser, L.; Ignatovich, V.; Veres, T.; Yaradaykin, S.
Periodic multilayers of various periods were prepared according to an algorithm proposed by the authors. The reflectivity properties of these systems were investigated using neutron reflectometry.The obtained experimental results were compared with the theoretical expectations. In first approximation, the results proved the main features of the theoretical predictions. These promising results initiate further research of such systems.
An optimal energy management system for islanded Microgrids based on multi-period artificial bee colony combined with Markov Chain
DEFF Research Database (Denmark)
Marzband, Mousa; Azarinejadian, Fatemeh
Optimal operation programming of electrical systems through minimization of production cost and market clearing price (MCP) as well as better utilization of renewable energy resources has attracted the attention of many researchers. To reach this aim, energy management systems (EMS) has been studied in many research activities. Moreover, demand response (DR) expands customer participation to power systems and results in a paradigm shift from conventional to interactive activities in power systems due to the progress of smart grid technology. Therefore, modelling of consumer characteristic in DR is becoming so important issues in these systems. The customer information as the registration and participation information of DR is used to provide additional indices for evaluating customer response, such as consumer0s information based on the offer priority, DR magnitude, duration, and minimum cost of energy (COE). In this paper, a multi-period artificial bee colony (MABC) optimization algorithm is implemented for economic dispatch considering generation, storage and responsive load offers. The better performance of the proposed algorithm is shown in comparison with the modified conventional energy management system (MCEMS) and its effectiveness is validated experimentally over a Microgrid (MG) Testbed. The obtained results show cost reduction (by around 30%), convergence speed increase as well as remarkable improvement of efficiency and accuracy under uncertain conditions. An artificial neural network (ANN) combined with Markov-chain (MC) (ANN-MC) approach is used to predict non-dispatchable power generation and load demand considering uncertainties. Furthermore, other capabilities such as extendibility, reliability and flexibility are examined about the proposed approach.
Variability of the Spin Period of the White Dwarf in the Magnetic Cataclysmic Binary System EX Hya
Andronov, Ivan L
The observations of the two-periodic magnetic cataclysmic system EX Hya have been carried out, using the telescopes RC16 and TOA-150 of the Tzec Maun observatory. 6 nights of observations were obtained in 2010-2011 (alternatively changing filters VR). Also the databases of WASP, ASAS and AAVSO have been analyzed. Processing time series was carried out using the program MCV. We analyzed changes in the rotation period of the white dwarf, and based on our own and previously published moments of maximum. The ephemeris was determined for the maxima of the radiation flux associated with the rotation of the magnetic white dwarf: Tmax=2437699.89079(59) +0.0465464808(69).E-6.3(2)*10^{-13}E^2, which corresponds to the characteristic timescale of the rotation spin-up of 4.67(14)*10^6 years. This contradicts the estimated value of the mass of the white dwarf of 0.42M_\\odot, based on X-ray observations made by Yuasa et al (2010), however, is consistent with estimates of the masses of 0.79 M_\\odot (white dwarf) and 0.108 M...
CORS Baade-Wesselink method in the Walraven photometric system: the Period-Radius and the Period-Luminosity relation of Classical Cepheids
Molinaro, R.; Ripepi, V.; Marconi, M.; Bono, G.; Lub, J.; Pedicelli, S.; Pel, J. W.
We present a new derivation of the CORS Baade-Wesselink method in the Walraven photometric system. We solved the complete Baade-Wesselink equation by calibrating the surface brightness function with a recent grid of atmosphere models. The new approach was adopted to estimate the mean radii of a sample of Galactic Cepheids for which are available precise light curves in the Walraven bands. Current radii agree, within the errors, quite well with Cepheid radii based on recent o...
Hybrid functionals for large periodic systems in an all-electron, numeric atom-centered basis framework
Levchenko, Sergey V.; Ren, Xinguo; Wieferink, J³rgen; Johanni, Rainer; Rinke, Patrick; Blum, Volker; Scheffler, Matthias
We describe a framework to evaluate the Hartree-Fock exchange operator for periodic electronic-structure calculations based on general, localized atom-centered basis functions. The functionality is demonstrated by hybrid-functional calculations of properties for several semiconductors. In our implementation of the Fock operator, the Coulomb potential is treated either in reciprocal space or in real space, where the sparsity of the density matrix can be exploited for computational efficiency. Computational aspects, such as the rigorous avoidance of on-the-fly disk storage, and a load-balanced parallel implementation, are also discussed. We demonstrate linear scaling of our implementation with system size by calculating the electronic structure of a bulk semiconductor (GaAs) with up to 1,024 atoms per unit cell without compromising the accuracy.
Occupational irradiation by external radiation sources. Analysis of the control system data covering the period 1972 - 198a
International Nuclear Information System (INIS)
Occupational irradiation data, made available by the system of individual dosimetric control, are analyzed. It is demonstrated that the annual dose distribution is in accordance with the logarithm of normal distribution. The obtained values of the average dose in industry, medicine, science and educatuin during the period 1972 through 1980 are respectively 3.7 mSv, 1.0 mSv and 0.45 mSv. In some lines the average annual dose considerably exceeds the average annual dose for the respective branch, e.g. for workers in gamma defectoscopy it amounts to 9.1 mSv, while for medical personnel of deep and curi therapy - 2.1 mSv. (author)
Effects of time delay and noise correlation on noise enhanced stability and resonant activation in a periodically modulated bistable system
International Nuclear Information System (INIS)
This work analyzes numerically the effects of delay time ? and cross-correlation strength between noises ? on the phenomena of noise enhanced stability (NES) and resonant activation (RA) in a periodically modulated bistable system. The simulation results indicate that: (i)Āmultiplicative noise can produce the NES effect only for the larger ?, while additive noise always induces the NES effect; (ii) for the NES phenomenon induced by additive noise, there is a characteristic value of ?, below which the increasing of ? enhances it and above which the effect of ? reverses; however, the increasing of ? can only enhance the NES effect induced by multiplicative noise; (iii) increasing ? weakens the NES effect induced by additive noise and strengthens that induced by multiplicative noise; and (iv) the RA effect becomes more and more pronounced while the RA minimum of the mean first-passage time increases with the increase of ? or ?. (paper)
Periodic Review Probabilistic Multi-Item Inventory System with Zero Lead Time under Constraint and Varying Holding Cost
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Naglaa H. El-Sodany
Full Text Available Problem statement: This study treats the probabilistic safety stock n-items inventory system having varying holding cost and zero lead-time subject to linear constraint. Approach: The expected total cost is composed of three components: the average purchase cost; the expected order cost and the expected holding cost. Results: The policy variables for this model are the number of periods N*r and the optimal maximum inventory levelĀQ*mr and the minimum expected total cost. Conclusion/Recommendations: We can obtain the optimal values of these policy variables by using the geometric programming approach. A special case is deduced and an illustrative numerical example is added.
... Date reviewed: October 2013 Back 1 ? 2 For Teens For Kids For Parents MORE ON THIS TOPIC Gyn Checkups I'm 14 and I Don't Have My Period Yet. Is This Normal? Can a Girl Get Pregnant if She Has Sex During Her Period? Birth Control Pill Coping With ...
Searches for periodic neutrino emission from binary systems with 22 and 40 strings of IceCube
Abbasi, R; Abu-Zayyad, T; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Allen, M M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Bay, R; Alba, J L Bazo; Beattie, K; Beatty, J J; Bechet, S; Becker, J K; Becker, K -H; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bose, D; B÷ser, S; Botner, O; Brown, A M; Buitink, S; Caballero-Mora, K S; Carson, M; Chirkin, D; Christy, B; Clevermann, F; Cohen, S; Colnard, C; Cowen, D F; Silva, A H Cruz; D'Agostino, M V; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; Degner, T; Demir÷rs, L; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; DĒaz-Vķlez, J C; Dierckxsens, M; Dreyer, J; Dumm, J P; Dunkman, M; Eisch, J; Ellsworth, R W; EngdegÕrd, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Fox, B D; Franckowiak, A; Franke, R; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Gl³senkamp, T; Goldschmidt, A; Goodman, J A; G¾ra, D; Grant, D; Griesel, T; Gro▀, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Han, K; Hanson, K; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, B; Homeier, A; Hoshina, K; Huelsnitz, W; H³l▀, J -P; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Johansson, H; Kampert, K -H; Kappes, A; Karg, T; Karle, A; Kenny, P; Kiryluk, J; Kislat, F; Klein, S R; K÷hne, J -H; Kohnen, G; Kolanoski, H; K÷pke, L; Kopper, S; Koskinen, D J; Kowalski, M; Kowarik, T; Krasberg, M; Kroll, G; Kurahashi, N; Kuwabara, T; Labare, M; Laihem, K; Landsman, H; Larson, M J; Lauer, R; L³nemann, J; Madsen, J; Marotta, A; Maruyama, R; Mase, K; Matis, H S; Meagher, K; Merck, M; Mķszßros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Montaruli, T; Morse, R; Movit, S M; Nahnhauer, R; Nam, J W; Naumann, U; Nygren, D R; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Heros, C Pķrez de los; Petrovic, J; Piegsa, A; Pieloth, D; Porrata, R; Posselt, J; Price, P B; Przybylski, G T; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Rodrigues, J P; Rothmaier, F; Rott, C; Ruhe, T; Rutledge, D; Ruzybayev, B; Ryckbosch, D; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Schmidt, T; Sch÷nwald, A; Schukraft, A; Schultes, A; Schulz, O; Schunck, M; Seckel, D; Semburg, B; Seo, S H; Sestayo, Y; Seunarine, S; Silvestri, A; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stezelberger, T; Stokstad, R G; St÷▀l, A; Strahler, E A; Str÷m, R; St³er, M; Sullivan, G W; Swillens, Q; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Tosi, D; van Eijndhoven, N; Vandenbroucke, J; Van Overloop, A; van Santen, J; Vehring, M; Voge, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wischnewski, R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Zoll, M
Recent observations of GeV/TeV photon emission from several X-ray binaries have sparked a renewed interest in these objects as galactic particle accelerators. In spite of the available multi-wavelength data, their acceleration mechanisms are not determined, and the nature of the accelerated particles (hadrons or leptons) is unknown. While much evidence favors leptonic emission, it is very likely that a hadronic component is also accelerated in the jets of these binary systems. The observation of neutrino emission would be clear evidence for the presence of a hadronic component in the outflow of these sources. In this paper we look for periodic neutrino emission from binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. The results of two searches are presented that differ in the treatment of the spectral shape and phase of the emission. The 'generic' search allows parameters to vary freely and best fit values, in a 'model-dependent' search, predictions...
The shortest period M-dwarf eclipsing system BW3 V38, II: determination of absolute elements
Maceroni, C
The spectroscopic data for the short-period (0.1984 d)eclipsing binary V38, discovered by the OGLE micro-lensing team in Baade's Window field BW3, are analyzed. Radial velocity curves are derived from mid-resolution spectra obtained with EMMI-NTT at ESO - La Silla, and a simultaneous solution of the existing light curve by OGLE and of the new radial velocity curves is obtained. The system is formed by almost twin M3e dwarf components that are very close, but not yet in contact. The spectra of both dwarfs show signatures of the presence of strong chromospheres. Spectroscopy definitely confirms, therefore, what was suggested on the basis of photometry: BW3 V38 is indeed a unique system, as no other similar binary with M components and in such a tight orbit is known. Within the limits posed by the relatively large errors, due to the combined effect of system faintness and of the constraints on exposure time, the derived physical parameters seem to agree with the relations obtained from the other few known eclips...
Searches for Periodic Neutrino Emission from Binary Systems with 22 and 40 Strings of IceCube
Abassi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Benabderrahmane, M. L.; BenZvi, S.; Berdermann, J.; Berghaus, P.
Recent observations of GeV /TeV photon emission from several X-ray binaries have sparked a renewed interest in these objects as galactic particle accelerators. In spite of the available multi-wavelength data, their acceleration mechanisms are not determined, and the nature of the accelerated particles (hadrons or leptons) is unknown. While much evidence favors leptonic emission, it is very likely that a hadronic component is also accelerated in the jets of these binary systems. The observation of neutrino emission would be clear evidence for the presence of a hadronic component in the outflow of these sources. In this paper we look for periodic neutrino emission from binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. The results of two searches are presented that differ in the treatment of the spectral shape and phase of the emission. The 'generic' search allows parameters to vary freely and best fit values, in a 'model-dependent' search, predictions are used to constrain these parameters. We use the IceCube data taken from May 31, 2007 to April 5, 2008 with its 22-string configuration, and from April 5, 2008 and May 20, 2009 with its 40-string configuration. For the generic search and the 40 string sample, we find that the most significant source in the catalog of 7 binary stars is Cygnus X-3 with a 1.8% probability after trials (2.10" sigma one-sided) of being produced by statistical fluctuations of the background. The model-dependent method tested a range of system geometries - the inclination and the massive star's disk size - for LS I+61 deg 303, no significant excess was found.
Variability of the Rotation Period of the White Dwarf in the Magnetic Cataclysmic Binary System EX Hya
Andronov, I. L.; Breus, V. V.
Observations have been made of the two-period magnetic cataclysmic system EX Hya using the RC16 and TOA-150 telescopes at the Tzec Maun Observatory on 6 nights during 2010-2011 (with alternating changeable VR filters). Data from the WASP, ASAS, and AAVSO archives have also been analyzed. The time series were processed using the MCV program. Changes in the rotation period of the white dwarf are analyzed on the basis of our own and previously published data on the times of the maxima. An ephemeris is obtained for the maximum radiative fluxes associated with the rotation of the magnetic white dwarf, T max =2437699.89079(59) + 0.0465464808(69)Ģ E - 6.3(2) Ģ 10-13 E 2, which corresponds to a characteristic time scale of 4.67(12) Ę 106 years for the rotation spin-up. This value conflicts with the estimated mass of the white dwarf, 0.42 M ?, derived from X-ray observations by Yuasa, et al. (2010), but is consistent with the estimated masses 0.79 M ? (white dwarf) and 0.108 M ? (red dwarf) obtained earlier by Beuermann and Reinsch (2008) and the assumption that capture of an accretion plasma by the magnetic field of the white dwarf is taking place near the boundary of the Roche lobe. The analyzed times of the minima do not support the assumption by Mauche, et al. (2009), of a statistically significant cubic term in the ephemeris. Despite the occurrence of outbursts in EX Hya, there are substantial differences from DO Dra, which supports the inclusion of the corresponding groups "outbursting intermediate polars" and "magnetic dwarf novae" in the detailed classification of intermediate polars.
Significant progression of load on the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using the Anatoly Gravitational System, in a 10-week training period
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Burke DT
Full Text Available David T Burke,1 David Tran,1 Di Cui,1 Daniel P Burke,2 Samir Al-Adawi,3 Atsu SS Dorvlo41Emory University Medical School, Atlanta, GA, USA; 2Georgia College and State University, GA, USA; 3Department of Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman; 4Department of Mathematics and Statistics, College of Science, Sultan Qaboos University, Muscat, OmanAbstract: In an age of increasing numbers of lifestyle diseases and plasticity of longevity, exercise and weight training have been increasingly recognized as both preventing and mitigating the severity of many illnesses. This study was designed to determine whether significant weight-lifting gains could be realized through the Anatoly Gravitational System. Specifically, this study sought to determine whether this once-weekly weight-training system could result in significant weekly strength gains during a 10-week training period. A total of 50 participants, ranging in age from 17 to 67 years, completed at least 10 weekly 30-minute training sessions. The results suggest participants could, on average, double their weight-lifting capacity within 10 sessions. This preliminary study, which would require further scrutiny, suggests the Anatoly Gravitational System provides a rather unique opportunity to load the musculoskeletal system with extremely high loads, with rapid weekly weight gains, using only short weekly training sessions. More studies are warranted to scrutinize these findings.Keywords: Anatoly Gravitational System, weight training, musculoskeletal system
Evaluation of mercury contamination in sediments from Santos - Sao Vicente Estuarine system, in period of 1996 -2000
International Nuclear Information System (INIS)
The distribution of mercury contamination in the Santos - Sao Vicente Estuarine System was observed through the analysis of seventy seven surface sediments samples collected in two series. In different periods and points, since the Channel of Piacaguera, the head of the system, , through the estuarine arms of Santos and Sao Vicente as far as the Bay of Santos, about 30 Km downstream, and in different mangrove areas, including industrial and harbor influence zones. The obtained values ranged from 0.03 to 1.19 ?g g -1 About 90% of the samples of the first series collected among 1997-1998 and 50% of the second series collected among 1999-2000 presented levels of Hg > 0,13 ?g g -1 ,limit considered by the Canadian legislation and adopted by CETESB, below which doesn't happen adverse effect in the biological community. And about 35% of samples of the first series and 11 % of the second series presented concentrations of Hg > 0.698 ?g g -1 probable level of occurrence of adverse effect in the biological community. These results indicate an increase of the mercury levels caused by the industrial, port and urban activities. The mercury concentration in sediments was determined by using an Atomic Absorption Spectrophotometer, coupling with a flow injection system by a cold vapor generation, using a manual injection valve (FIA-CVAAS). The estimate of the uncertainties associated to this procedure was calculated. The following elements were also determined: Fe, Al, Zn, Ni, Pb, Cd, Cr and Co in 46 samples of the second series, by atomic absorption spectrometry. In order to verify possible relationship among all the investigated elements in the samples sediments, was carried out a statistical study, using the SPSS-8.0 software. Pearson correlation and Principal Component's analysis were used for with the objective to identify of major relationship for additional exploration of the general behavior of the data. (author)
Periodicities in the high-mass X-ray binary system RX J0146.9+6121/LS I+61 235
Sarty, Gordon E; Huziak, Richard; Catalan, Lionel J J; Luciuk, Diane; Crawford, Timothy R; Lane, David J; Pickard, Roger D; Grzybowski, Thomas A; Closas, Pere; Johnston, Helen; Balam, David; Wu, Kinwah
The high-mass X-ray binary RX J0146.9+6121, with optical counterpart LS I+61 235 (V831 Cas), is an intriguing system on the outskirts of the open cluster NGC 663. It contains the slowest X-ray pulsar known with a pulse period of around 1400s and, primarily from the study of variation in the emission line profile of H alpha, it is known to have a Be decretion disk with a one-armed density wave period of approximately 1240d. Here we present the results of an extensive photometric campaign, supplemented with optical spectroscopy, aimed at measuring short time-scale periodicities. We find three significant periodicities in the photometric data at, in order of statistical significance, 0.34d, 0.67d and 0.10d. We give arguments to support the interpretation that the 0.34d and 0.10d periods could be due to stellar oscillations of the B type primary star and that the 0.67d period is the spin period of the Be star with a spin axis inclination of 23 +10 -8 degrees. We measured a systemic velocity of -37.0 +- 4.3 km/s c...
Expression of clock genes period and timeless in the central nervous system of the Mediterranean flour moth, Ephestia kuehniella.
Kobelkovß, Alena; Zßvodskß, Radka; Sauman, Ivo; Bazalovß, Olga; Dolezel, David
Homologous circadian genes are found in all insect clocks, but their contribution to species-specific circadian timing systems differs. The aim of this study was to extend research within Lepidoptera to gain a better understanding of the molecular mechanism underlying circadian clock plasticity and evolution. The Mediterranean flour moth, Ephestia kuehniella (Pyralidae), represents a phylogenetically ancestral lepidopteran species. We have identified circadian rhythms in egg hatching, adult emergence, and adult locomotor activity. Cloning full-length complementary DNAs and further characterization confirmed one copy of period and timeless genes in both sexes. Both per and tim transcripts oscillate in their abundance in E. kuehniella heads under light-dark conditions. PER-like immunoreactivity (PER-lir) was observed in nuclei and cytoplasm of most neurons in the central brain, the ventral part of subesophageal complex, the neurohemal organs, the optic lobes, and eyes. PER-lir in photoreceptor nuclei oscillated during the day with maximal intensity in the light phase of the photoperiodic regime and lack of a signal in the middle of the dark phase. Expression patterns of per and tim messenger RNAs (mRNAs) were revealed in the identical location as the PER-lir was detected. In the photoreceptors, a daily rhythm in the intensity of expression of both per mRNA and tim mRNA was found. These findings suggest E. kuehniella as a potential lepidopteran model for circadian studies. PMID:25637625
Morphometric analysis of diffuse endocrine system's components in esoph-agogastroduodenal zone in different periods after cholecystectomy
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Kozlova I.V.
Full Text Available The examination of morphofunctional features of esophagus, stomach, and duodenum as well as the role of diffusive endocrine system's cells in development of esophagogastroduodenal zone in patients without gallbladder is the purpose of the study. 80 patients with various periods after cholecystectomy and 72 patients with cholelithiasis were examined. Endo-scopic, histological and immuno-histochemical studies were carried out against all examined patients. The amount of epitheliocytes producing motilin (EC2, glucagon (L, and pancreatic polypeptide (PP in duodenum were determined using antibodies sets. Esophagitis, atrophic- and reflux-gastritis, duodenal reflux are positively rather frequently met, atrophy and dysplasia of gastric mucous membrane increase in patients without gallbladder during the time after cholecystectomy. Hypoplasia of epithelial cells producing motilin, glucagon and pancreatic polipetide progresses. The development of duodenal and gastroesophagial reflux is associated with hypoplasia of epithelicytes producing motilin; the development of erosive changes is connected with hypoplasia of L and PP cells; the development of atrophic changes is closely related with hypoplasia of all studied cell types. The decrease of hormone producing epythelicytes promotes initiation and persistence of morphofunctional changes in esophagogastricduodenal zone. And this in turn can serve as additional diagnostic and prognostic criterion.
Maximum entropy state of the quasi-geostrophic bi-disperse point vortex system: bifurcation phenomena under periodic boundary conditions
International Nuclear Information System (INIS)
We investigate the statistical mechanics of quasi-geostrophic point vortices of mixed sign (bi-disperse system) numerically and theoretically. Direct numerical simulations under periodic boundary conditions are performed using a fast special-purpose computer for molecular dynamics (GRAPE-DR). Clustering of point vortices of like sign is observed and two-dimensional (2D) equilibrium states are formed. It is shown that they are the solutions of the 2D mean-field equation, i.e. the sinh-Poisson equation. The sinh-Poisson equation is generalized to study the 3D nature of the equilibrium states, and a new mean-field equation with the 3D Laplace operator is derived based on the maximum entropy theory. 3D solutions are obtained at very low energy level. These solution branches, however, cannot be traced up to the higher energy level at which the direct numerical simulations are performed, and transitions to 2D solution branches take place when the energy is increased. (paper)
Light Microscopic Evaluation of Cardio-vasculare System in Alloksan-induced Diabetic Rats in Acute Period
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Selen Bahńeci
Full Text Available Diabetic cardiomyopathy is one of the chronic complication of diabetes and acute effects of diabetes on heart and aorta is not clear. We aimed to determine acute effects of diabetes on cardio-vasculare system with light microscopy. We used 20 Spraque-Dawley rats and applied 150 mg/kg alloxan, intraperitoneally for inducing diabetes and 1 ml SF in control group. After 24 hours, venous blood samples were measured. Blood glucose levels higher than 250 mg/dl were accepted as DM and treated with 4 IU/d human ins³lin. After 7 days rats were sacrified under ketamin anaesthesia. Heart and aorta were fixed in 10 % buffered formalin. The sectiones were embedded in paraffin and were serially sectioned at 5 ?m thickness, then stained with Hematoxyline-Eosine (H&E and HeidenheinÆs Azan modification.There was no histopathological changes in cardiac muscle cells in control group. But there was a heterogen appearance in cardiac muscle cells and we determined some hydropic degenerations in some of the cardiac muscle cells and a minimal fibrosis in perivasculare and interstitial area in diabetic group. All histological stratums of aorta were seen normally in control group. In diabetic group, there was a clear anisostosis in smooth muscle cells and decreased in nucleus of smooth muscle cells in tunica media. We concluted that DM is caused degeneration and fibrosis in cardiac muscle cells and effective on smooth muscle cells in aorta in acute period.
Maximum entropy state of the quasi-geostrophic bi-disperse point vortex system: bifurcation phenomena under periodic boundary conditions
Energy Technology Data Exchange (ETDEWEB)
Funakoshi, Satoshi; Sato, Tomoyoshi; Miyazaki, Takeshi, E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [Department of Mechanical Engineering and Intelligent Systems, University of Electro-Communications, 1-5-1, Chofugaoka, Chofu, Tokyo 182-8585 (Japan)
We investigate the statistical mechanics of quasi-geostrophic point vortices of mixed sign (bi-disperse system) numerically and theoretically. Direct numerical simulations under periodic boundary conditions are performed using a fast special-purpose computer for molecular dynamics (GRAPE-DR). Clustering of point vortices of like sign is observed and two-dimensional (2D) equilibrium states are formed. It is shown that they are the solutions of the 2D mean-field equation, i.e. the sinh-Poisson equation. The sinh-Poisson equation is generalized to study the 3D nature of the equilibrium states, and a new mean-field equation with the 3D Laplace operator is derived based on the maximum entropy theory. 3D solutions are obtained at very low energy level. These solution branches, however, cannot be traced up to the higher energy level at which the direct numerical simulations are performed, and transitions to 2D solution branches take place when the energy is increased. (paper)
Short term Variability of the Sun Earth System: An Overview of Progress Made during the CAWSES II Period
Gopalswamy, Nat; Yan, Yihua
This paper presents an overview of results obtained during the CAWSES II period on the short term variability of the Sun and how it affects the near Earth space environment. CAWSES II was planned to examine the behavior of the solar terrestrial system as the solar activity climbed to its maximum phase in solar cycle 24. After a deep minimum following cycle 23, the Sun climbed to a very weak maximum in terms of the sunspot number in cycle 24 (MiniMax24), so many of the results presented here refer to this weak activity in comparison with cycle 23. The short term variability that has immediate consequence to Earth and geospace manifests as solar eruptions from closed field regions and high speed streams from coronal holes. Both electromagnetic (flares) and mass emissions (coronal mass ejections, CMEs) are involved in solar eruptions, while coronal holes result in high speed streams that collide with slow wind forming the so called corotating interaction regions (CIRs). Fast CMEs affect Earth via leading shocks ...
The origin of the solar system: implications for transneptunian planets and the nature of the long-period comets
International Nuclear Information System (INIS)
The major stages of division and evolution of the Jupiter-Sun system are described. Similarities between the massive rotating proto-Jupiter (PJ) and the classical protoplanetary discs are pointed out. The process of planetoid condensation inside PJ is discussed. The most probable site of the condensation is the region of the first Lagrangian point. The planetoids condensed were lost by PJ as a result of its fast mass decrease. A gas dynamic consideration of the motion of planetoids in PJ yields 1000-3000 yr as a time scale for the PJ's mass loss. The number of the moonlike bodies lost (the remaining Galilean satellites fixing their lower mass limit) could reach 104. Evolution of such interacting bodies results in the formation beyond Neptune of a cloud (up to 103) of moonlike (and more massive) planets. The excess concentration of the long-period comets aphelia in this area implies their genetic relation to the planets. A concept of a joint planeto-cometary cloud is introduced. A concrete hydrodynamic mechanism of ice ejection from planets into space, viz. the formation of cumulative (Monroe) jets, is pointed out. A program of further investigations is outlined and recommendations given for an experimental check on the implications of the new cosmogonic concepts. (Auth.)
In this activity, students learn to recognize periodicity within a set of data by using the examples of pendulums and binary star systems. Included are prerequisites, enrichment activities, materials lists, datasets, instructions, and links to additional information..
Diudea, Mircea V; Nagy, Csaba L; Silaghi-Dumitrescu, Ioan; Graovac, Ante; Janezic, Dusanka; Viki?-Topi?, Drazen
Various cages are constructed by using three types of caps: f-cap (derived from spherical fullerenes by deleting zones of various size), kf-cap (obtainable by cutting off the polar ring, of size k), and t-cap ("tubercule"-cap). Building ways are presented, some of them being possible isomerization routes in the real chemistry of fullerenes. Periodic cages with ((5,7)3) covering are modeled, and their constitutive typing enumeration is given. Spectral data revealed some electronic periodicity in fullerene clusters. Semiempirical and strain energy calculations complete their characterization. PMID:15807490
Advanced development of particle beam probe diagnostic systems: Technical progress report covering the period October 1, 1985-August 31, 1987
International Nuclear Information System (INIS)
The primary emphasis during this time period was on documenting and improving fluctuation measurements with the heavy ion beam probe, improving the instrumentation and hardware and evaluating the requirements for scaling beam probes to reactor size confinement devices. All of the work has been reported in periodic progress reports and only a brief summary will be given here. 13 refs
Pressure surge in a rapid shutdown system: update of calculations by measurement results-a procedure within periodical controls
International Nuclear Information System (INIS)
A rapid shutdown system of a BWR consists of four tank pipes (ND 250) and two ring pipes (ND 150). The tank pipes connect three pressure tanks with the ring pipes which distribute the hydraulic pressure to the so-called scram pipes. The scram pipes drive the steering rods. Beyond the normal operation conditions shutdowns represent the main loading. Within the concept for periodical examinations of the rapid shutdown system different testing methods as well as calculations are established. The major portion of the welding seams in this system is examined by non-destructive testing like ultrasonic measurement. For completion of the information about the integrity of the piping system mechanical measurements as well as numerical calculations are carried out. At first measurements were performed during pressure surge at boundary conditions (20 bar reactor pressure) which are expected to result in increased loading for the system. The measurements are focused on positions at the test pipes outside the containment because with respect to the plant experience the two ring pipes are expected to remain in their static position during pressure surge. With the measurements the real accelerations, displacements and especially strains are documented at positions which are supposed to be representative for the whole system as well as near welding seams which cannot be examined by ultrasonic measurements. Calculations were done after the measurements. In the calculation model the cosurements. In the calculation model the complete piping with ND 250 and ND 150 is included with the different supporting facilities like fixed points at the tanks, shock absorbers, sliding contacts, transitions at the containment shell and sliding contacts of the two ring pipes. Two load cases are investigated: normal operation and pressure surge. The pressure surge loading of the pipe is input to the piping code from compatible data files of a separate hydraulic code. First a linear dynamic calculation gives some insight in the motion as well as in the stress distribution of the whole system, especially for the positions which are not accessible for measurements. With a detailed finite element model the stress concentration at the spherical fittings for the transitions tank-/ring-pipe are analysed. Second a more refined calculation model with respect to non-linear effects of shock absorbers and friction at sliding contacts give more realistic results in comparison to the measurement. But the comparisons of calculations and measurement results show that the real responses are overestimated by both calculations, somewhat more by the linear model and somewhat less by the nonlinear model. Therefore two further steps for verification of the calculations are performed with the focus on the transient behaviour of the ring pipe during pressure surge: Measurement of displacements of the ring pipes as well as refinement of the calculation model in the formulation of the boundary conditions of the two ring pipes. (authors)
Instabilities in fluid layers and in reaction-diffusion systems: Steady states, time-periodic solutions, non-periodic attractors, and related convective and otherwise non-linear phenomena
International Nuclear Information System (INIS)
Thermoconvective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Benard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (author)
Instabilities in fluid layers and in reaction-diffusion systems: Steady states, time-periodic solutions, non-periodic attractors, and related convective and otherwise non-linear phenomena
International Nuclear Information System (INIS)
Thermo convective instabilities in horizontal fluid layers are discussed with emphasis on the Rayleigh-Bernard model problem. Steady solutions and time-dependent phenomena (relaxation oscillations and transition to turbulence) are studied within the nonlinear Boussinesq-Oberbeck approximation. Homogeneous steady solutions, limit cycles, and inhomogeneous (ordered) spatial structures are also studied in simple reaction-diffusion systems. Lastly, the non-periodic attractor that appears at large Rayleigh numbers in the truncated Boussinesq-Oberbeck model of Lorenz, is constructed, and a discussion of turbulent behavior is given. (Author) 105 refs
Broad iron emission line and kilohertz quasi-periodic oscillations in the neutron star system 4U 1636-53
Sanna, Andrea; Mķndez, Mariano; Altamirano, Diego; Belloni, Tomaso; Hiemstra, Beike; Linares, Manuel
Both the broad iron (Fe) line and the frequency of the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low-mass X-ray binaries (LMXBs) can potentially provide independent measures of the inner radius of the accretion disc. We use XMM-Newton and simultaneous Rossi X-ray Timing Explorer observations of the LMXB 4U 1636-53 to test this hypothesis. We study the properties of the Fe K? emission line as a function of the spectral state of the source and the frequency of the kHz QPOs. We find that the inner radius of the accretion disc deduced from the frequency of the upper kHz QPO varies as a function of the position of the source in the colour-colour diagram, in accordance with previous work and with the standard scenario of accretion disc geometry. On the contrary, the inner disc radius deduced from the profile of the iron line is not correlated with the spectral state of the source. The values of the inner radius inferred from kHz QPOs and iron lines, in four observations, do not lead to a consistent value of the neutron star mass, regardless of the model used to fit the iron line. Our results suggest that either the kHz QPO or the standard relativistic Fe line interpretation does not apply for this system. Furthermore, the simultaneous detection of kHz QPOs and broad iron lines is difficult to reconcile with models in which the broadening of the iron line is due to the reprocessing of photons in an outflowing wind.
Water erosion during a 17-year period under two crop rotations in four soil management systems on a Southbrazilian Inceptisol
Bertol, Ildegardis; Vidal Vßzquez, Eva; Paz Ferreiro, Jorge
Soil erosion still remains a persistent issue in the world, and this in spite of the efforts to ameliorate soil management systems taken into account the point of view of environmental protection against soil losses. In South Brazil water erosion is mainly associated to rainfall events with a great volume and high intensity, which are more or less evenly distributed all over the year. Nowadays, direct drilling is the most widely soil management system used for the main crops of the region. However, some crops still are grown on conventionally tilled soils, which means mainly ploughing and harrowing and less frequently chisel ploughing. In Lages-Santa Catarina State, Brazil, a plot experiment under natural rain was started in 1992 on an Inceptisol with the aim of quantifying soil and water losses. Treatments included bare and vegetated plots. The crop succession was: oats (Avena strigosa), soybean (Glycine max), vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and beans (Phaseolus vulgaris). Soil tillage systems investigated in this study were: i) conventional tillage (CT), ii) reduced tillage (MT), iii) no tillage (NT) under crop rotation and iv) conventional tillage on bare soil (BS). Treatments CT and BS involved ploughing plus twice harrowing, whereas MT involved chisel ploughing plus harrowing. Rainfall erosivity from January 1 1992 to December 31 2009 was calculated. Soil losses from the BS treatment along the 17 year study period were higher than 1200 Mg ha-1. Crop cover significantly reduced erosion, so that under some crops soil losses in the CT treatment were 80% lower than in the BS treatment. In turn soil losses in the MT treatment, where tillage was performed by chiselling and harrowing, were on average about 50% lower than in the CT treatment. No tillage was the most efficient soil management system in reducing soil erosion, so that soil losses in the NT treatment were about 98% lower than in the BS treatment. The three vegetated treatments, CT, MT and NT showed a lower efficiency in reducing water losses than soil losses. Water losses by runoff during a number of events were of the same order of magnitude for all the management systems studied here; which was mainly true when the volume of rainfall was high and the lag between successive events was small. In general, soil losses in the autumn-winter seasons were lower than under the spring-summer seasons. Soil losses showed a positive correlation with rainfall erosivity. However, the degree of dependence between these two variables decreased as the efficiency of soil management in controlling soil erosion increased. The large soil and water losses in the BS and CT treatments suggest that there is a need to implement soil conservation measures in the study region. In this context soil conservation would take advantage from soil cover by previous crop residue as well as from terrace building. Acknowledgement: This work was partly supported by Spanish Ministry of Education (Project CGL2005-08219-C02).
Development of radiation method for production of genetic mutant using microspore culture system. 2. Genetic effect of ?-radiation on fertilization period flower of the colza
International Nuclear Information System (INIS)
By using cut flower culture method, effects of ?-ray radiation on mutant induction of fertilization period flower of the colza were investigated. Defining a seed formed after irradiation to M1, for M2 generation obtained by once and M3 generation obtained twice autophagy thereafter, systems different morphologically from its original kind were checked. As a result, it was confirmed that a system with rounded leaves, a system with spotted leaves, a system with fat end of pod, a system with deformed shape of pod, and so forth were found and mutant induction of radiation using cut flower culture was effective. (G.K.)
Optimization of periodic testing frequency of a reactor protection system based on a risk-cost model and public risk perception
International Nuclear Information System (INIS)
Research highlights: ? Risk, cost, and public risk perception are incorporated to optimize test frequency. ? Protection system unavailability decreases with an increasing test frequency. ? CDF and spurious trip rate increase with human errors. ? Shorter interval tests are notably beneficial when the human error level is very low. ? Test error, moderator temperature coefficient, trip cost are key factors. - Abstract: Techniques for optimizing the frequency of periodic surveillance testing of nuclear power plant (NPP) safety systems have been receiving increased attention and growing importance because of the need to reduce system unavailability and maintenance cost. Economic losses from maintenance human errors should be included in estimating periodic testing and maintenance costs because the losses increase with maintenance human errors. This paper proposes a method for optimizing periodic testing intervals of a digital reactor protection system by balancing risk and cost of periodic surveillance tests, in which maintenance human error and public risk perception have been reflected. The risk and costs were estimated from both plant operator and socio-economic standpoints. This model determines the optimal testing frequency for the minimum value of an objective function that consists of all costs, including the monetary values of the consequence of maintenance human errors and reactor core damage. We present a case study using our model for the OPR1000 plant our model for the OPR1000 plant. The study results show the significance of reducing human errors in periodic testing and maintenance. The proposed method is expected to be useful to NPP operators as well as regulators for evaluating the optimal periodic testing frequency of a nuclear reactor protection system and for obtaining information needed in decision making processes.
Efficient periodic band diagram computation using a finite element method, Arnoldi eigensolver and sparse linear system solver
Garnier, Romain; Pascal, Olivier
We present here a Finite Element Method devoted to the simulation of 3D periodic structures of arbitrary geometry. The numerical method based on ARPACK and PARDISO libraries, is discussed with the aim of extracting the eigenmodes of periodical structures and thus establishing their frequency band gaps. Simulation parameters and the computational optimization are the focus. Resolution will be used to characterize EBG (Electromagnetic Band Gap) structures, such as plasma rods and metallic cubes.
Interfacial chemistry in solvent extraction systems. Final report for the period June 1, 1994 - May 31, 1998
Energy Technology Data Exchange (ETDEWEB)
Neuman, Ronald D.
The interfacial chemistry that occurs in the liquid/liquid extraction of metals ions still remains very incompletely understood at the molecular level. The objective of this comprehensive research program has been to further the fundamental understanding of this complex chemistry by systematically investigating the interfacial behavior of extraction reagents and their interactions with metal ions at both macroscopic (liquid/liquid) and microscopic (reversed micelles) interfaces. Although the importance of the macroscopic interface is well recognized, it is less appreciated that microscopic interfaces, i.e., association microstructure such as reversed micelles, are often present under practical conditions and play a key role in liquid/liquid extraction. An improved knowledge of the interfacial behavior of extractant molecules is of the utmost importance as it relates to the efficacy (extent, selectivity and rate) of the extraction process. During the recent grant period the authors have more intensively investigated the physicochemical nature of metal-extractant aggregates (or microscopic interfaces) in the organic phase of acidic organophosphorus extraction systems from the perspective of colloid and surface science. Since industrial extraction systems are very complex, the authors emphasized the study of the aggregation behavior in model extraction systems of pure metal salts of bis(2-ethylhexyl)phosphoric acid (HDEHP) (e.g., NaDEHP, Ni(DEHP){sub 2} CO(DEHP){sub 2}) or bis(2-ethylhexyl) sulfosuccinate, whose sodium salt (AOT) is the classical surfactant used often in studies of the structure and properties of reversed micelles, to eliminate any possible uncertainty in the metal-extractant complex composition. This approach evolved into a new initiative that utilized molecular modeling in order to clarify the molecular structure of metal-extractant micellar aggregates for which information is very difficult to obtain from direct experimental measurements. Significantly, they have obtained a number of novel findings that are contrary to conventional views of both the fundamentals of reversed micellar formation and growth as well as liquid/liquid extraction. These findings take on additional importance in view of the general increasing interest in micellar enhanced separation processes. In addition, they have continued to make significant progress in their efforts to develop new methodologies for characterization of the physicochemical nature of the macroscopic liquid/liquid interface by using advanced laser techniques. The research productivity has been nothing short of excellent. This is especially so in view of the very difficult and challenging measurements that they proposed for investigating the structure and dynamics of the liquid/liquid interface, as well as the accomplishments in developing totally new concepts such as the open water-channel model of reversed micelles. Eighteen (18) papers and abstracts have been published since the submittal of the last three-year DOE progress report. Furthermore, several additional papers are in various stages of publication and preparation. In addition, they have given 12 presentations describing various aspects of the liquid/liquid extraction and related research activities.
Biochemical Technology Program progress report for the period January 1--June 30, 1976. [Centrifugal analyzers and advanced analytical systems for blood and body fluids
Energy Technology Data Exchange (ETDEWEB)
Mrochek, J.E.; Burtis, C.A.; Scott, C.D. (comps.)
This document, which covers the period January 1-June 30, 1976, describes progress in the following areas: (1) advanced analytical techniques for the clinical laboratory, (2) fast clinical analyzers, (3) development of a miniaturized analytical clinical laboratory system, (4) centrifugal fast analyzers for animal toxicological studies, and (5) chemical profile of body fluids.
First and second order electromagnetic equivalency of inertial systems, based on the wavelength and the period as speed-dependant units of length and time
Sardin, G.
The cause for first and second order electromagnetic equivalency of inertial systems is approached from a different point of view than that of special relativity. While special relativity applies dilatation to time and contraction to space itself, the proposed framework applies restrictively these effects to the units of space and time, embodied in the beam wavelength and period, as perceived on the inertial system due to the Doppler effect. It is not space and time themselv...
O sistema oligßrquico representativo da Primeira Rep·blica / Le systĶme oligarchique de reprķsentation de la PremiĶre Rķpublique / The oligarchic representative system in the First Republican period of Brazil
Scientific Electronic Library Online (English)
Wanderley Guilherme dos, Santos.
Full Text Available [...] Abstract in english Between the absolutisms of the 17th and 18th centuries and the democratic variants identified after World War II, there remains a conceptual haze that hinders an understanding of the period's political and institutional history. With the oligarchy viewed sometimes as the seed of democracy and other [...] times as a vestige of autocracy, the period remains vulnerable to subjectivisms. The current article presents a different, trans-locally valid analytical model for the oligarchic system and attempts to demonstrate how the history of the Second Empire and First Republic of Brazil would appear in a preliminary approach using the general model.
Directory of Open Access Journals (Sweden)
Wies?aw Gog¾?
Full Text Available Heat transfer across periodically contacting end faces of two cylinders including thermal radiation is discussed. The effects of the thermal properties, the emissivities of the bodies, the thermal contact resistance, the level of temperatures and the mutual configuration of the two bodies on the heat transfer are illustrated with the results of numerical calculations.
Wies?aw Gog¾?; Tomasz Wi?niewski
Heat transfer across periodically contacting end faces of two cylinders including thermal radiation is discussed. The effects of the thermal properties, the emissivities of the bodies, the thermal contact resistance, the level of temperatures and the mutual configuration of the two bodies on the heat transfer are illustrated with the results of numerical calculations.
Periodic trajectories in the Hilbert space and generalized semi-classical bound states of many-body systems
International Nuclear Information System (INIS)
Using a stationary phase approximation to calculate a functional integral defined on continuous overcomplete sets of vectors of the Hilbert space, one derives a generalized semi-classical quantization condition for periodic trajectories in the Hilbert space. This quantization condition is interpreted in terms of a variational principle. Application to the time dependent Hartree-Fock approximation is presented. (orig.)
International Nuclear Information System (INIS)
Following a recommendation by the International Union for Pure and Applied Chemistry (IUPAC), the groups of the periodic table shall be numbered from 1 to 18, instead of I to VIII as before. The recommendations has been approved of by the Committee on Nomenclature of the American Chemical Society. The new system abandons the distinction between main groups (a) and auxiliary groups (b), which in the past frequently has been the reason for misunderstandings between European and American chemists, due to different handling. The publishing house VCH Verlagsgesellschaft recently produced a new periodic table that shows the old and the new numbering system together at a glance, so that chemists will have time to get familiar with the new system. In addition the new periodic table represents an extensive data compilation arranged by elements. The front page lists the chemical properties of elements, the back page their physical properties. (orig./EF)
SciDAC's Earth System Grid Center for Enabling Technologies Semi-Annual Progress Report for the Period October 1, 2009 through March 31, 2010
Energy Technology Data Exchange (ETDEWEB)
Williams, Dean N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foster, I. T. [Argonne National Lab. (ANL), Argonne, IL (United States); Middleton, D. E. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Ananthakrishnan, R. [Argonne National Lab. (ANL), Argonne, IL (United States); Siebenlist, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Shoshani, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sim, A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bell, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Drach, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ahrens, J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jones, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, D. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Chastang, J. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Cinquini, L. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Fox, P. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Harper, D. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Hook, N. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Nienhouse, E. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Strand, G. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); West, P. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Wilcox, H. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Wilhelmi, N. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Zednik, S. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States); Hankin, S. [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Schweitzer, R. [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States); Bernholdt, D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shipman, G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bharathi, S. [Univ. of Southern California, Marina Del Rey, CA (United States). Information Sciences Institute; Chervenak, A. [Univ. of Southern California, Marina Del Rey, CA (United States). Information Sciences Institute; Schuler, R. [Univ. of Southern California, Marina Del Rey, CA (United States). Information Sciences Institute; Su, M. [Univ. of Southern California, Marina Del Rey, CA (United States). Information Sciences Institute
This report summarizes work carried out by the ESG-CET during the period October 1, 2009 through March 31, 2009. It includes discussion of highlights, overall progress, period goals, collaborations, papers, and presentations. To learn more about our project, and to find previous reports, please visit the Earth System Grid Center for Enabling Technologies (ESG-CET) website. This report will be forwarded to the DOE SciDAC program management, the Office of Biological and Environmental Research (OBER) program management, national and international collaborators and stakeholders (e.g., the Community Climate System Model (CCSM), the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), the Climate Science Computational End Station (CCES), the SciDAC II: A Scalable and Extensible Earth System Model for Climate Change Science, the North American Regional Climate Change Assessment Program (NARCCAP), and other wide-ranging climate model evaluation activities).
Directory of Open Access Journals (Sweden)
Ljupcho AJDINSKI
Full Text Available The period from the middle of the XIX to the middle of the XX century (1947, i.e., till passing the Statute of the World Health Organization, is a period in which not only the concept and the relationship was created and built up but also the institutionalized system for care, education and rehabilitation of disabled people in the world. During this one-century-period, institutional forms of social care, special education, professional training of disabled people were created.Unfortunately, our country did not have such a historical background. The society was not ready yet to accept the new ideas and to implement in practice the contemporary concepts in regard to the social care of the population that had been for ages on the margins of life.
On the question of periodization training content and Paralympic athletes with disorders of the musculoskeletal system in the light of the general theory of sports training
Directory of Open Access Journals (Sweden)
Derkach V.N.
Full Text Available Purpose : To determine theoretically similar trends and differences in the periods of sports training athletes and Paralympic athletes with similar qualifications, without disabilities. Material : analyzed more than 80 references. Results : at present insufficiently developed periodization sports training many years to prepare athletes with disorders of the musculoskeletal system. Also - at the stage of maximum realization of individual empowerment athletes. This applies to the immediate preparation for the main competition. In the first case, periodization can be carried out on the basis of the classical theory. Also on stage, maximizing the individual capabilities. Need to adapt this theory to career achievements of athletes. Also, you must consider the disease. Conclusions : The main factors set differences training tools Paralympic athletes and physically healthy: increased attention to the psychological preparation for the Paralympics, inclusive education and sports training individualization programs already in the first stage of their training.
SciDAC's Earth System Grid Center for Enabling Technologies Semi-Annual Progress Report for the Period April 1, 2009 through September 30, 2009
Energy Technology Data Exchange (ETDEWEB)
Williams, Dean N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Foster, I. T. [Argonne National Lab. (ANL), Argonne, IL (United States); Middleton, D. E. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States)
This report summarizes work carried out by the ESG-CET during the period April 1, 2009 through September 30, 2009. It includes discussion of highlights, overall progress, period goals, collaborations, papers, and presentations. To learn more about our project, and to find previous reports, please visit the Earth System Grid Center for Enabling Technologies (ESG-CET) website. This report will be forwarded to the DOE SciDAC program management, the Office of Biological and Environmental Research (OBER) program management, national and international collaborators and stakeholders (e.g., the Community Climate System Model (CCSM), the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), the Climate Science Computational End Station (CCES), the SciDAC II: A Scalable and Extensible Earth System Model for Climate Change Science, the North American Regional Climate Change Assessment Program (NARCCAP), and other wide-ranging climate model evaluation activities). During this semi-annual reporting period, the ESG-CET team continued its efforts to complete software components needed for the ESG Gateway and Data Node. These components include: Data Versioning, Data Replication, DataMover-Lite (DML) and Bulk Data Mover (BDM), Metrics, Product Services, and Security, all joining together to form ESG-CET's first beta release. The launch of the beta release is scheduled for late October with the installation of ESG Gateways at NCAR and LLNL/PCMDI. Using the developed ESG Data Publisher, the ESG II CMIP3 (IPCC AR4) data holdings - approximately 35 TB - will be among the first datasets to be published into the new ESG enterprise system. In addition, the NCAR's ESG II data holdings will also be published into the new system - approximately 200 TB. This period also saw the testing of the ESG Data Node at various collaboration sites, including: the British Atmospheric Data Center (BADC), the Max-Planck-Institute for Meteorology, the University of Tokyo Center for Climate System Research, and the Australian National University. This period, a total of 14 national and international sites installed an ESG Data Node for testing. During this period, we also continued to provide production-level services to the community, providing researchers worldwide with access to CMIP3 (IPCC AR4), CCES, and CCSM, Parallel Climate Model (PCM), Parallel Ocean Program (POP), and Cloud Feedback Model Intercomparison Project (CFMIP), and NARCCAP data.
Modal Analysis in Periodic, Time-Varying Systems with emphasis to the Coupling between Flexible Rotating Beams and Non-Rotating Flexible Structures
DEFF Research Database (Denmark)
Saracho, C. M.; Santos, Ilmar
The analysis of dynamical response of a system built by a non-rotating structure coupled to flexible rotating beams is the purpose of this work. The effect of rotational speed upon the beam natural frequencies is well-known, so that an increase in the angular speeds leads to an increase in beam natural frequencies, the so-called centrifugal stiffening. The equations of motion of such a global system present matrices with time-depending coefficients, which vary periodically with the angular rotor speed, and introduce parametric vibrations into the system response. The principles of modal analysis for time-invariant linear systems are expanded to investigate time-varying systems. Concepts as eigenvalues and eigenvectors, which in this special case are also time-varying, are used to analyse the dynamical response of global system. The time-varying frequencies and modes are also illustrated.
Application of second-order M°ller-Plesset perturbation theory with resolution-of-identity approximation to periodic systems
Katouda, Michio; Nagase, Shigeru
Efficient periodic boundary condition (PBC) calculations by the second-order M°ller-Plesset perturbation (MP2) method based on crystal orbital formalism are developed by introducing the resolution-of-identity (RI) approximation of four-center two-electron repulsion integrals (ERIs). The formulation and implementation of the PBC RI-MP2 method are presented. In this method, the mixed auxiliary basis functions of the combination of Poisson and Gaussian type functions are used to circumvent the slow convergence of the lattice sum of the long-range ERIs. Test calculations of one-dimensional periodic trans-polyacetylene show that the PBC RI-MP2 method greatly reduces the computational times as well as memory and disk sizes, without the loss of accuracy, compared to the conventional PBC MP2 method.
A multi-wavelength study of the long-period AM Her system E2003+225
International Nuclear Information System (INIS)
X-ray, UV and optical observations are presented of the longest period AM Her object E2003+225 from 1983 October 12, together with a new linear polarization ephemeris. The optical and X-ray data were obtained simultaneously and the UV observations were carried out on the same day. A 6-hr observation with the EXOSAT 500 line mm-1 objective grating restricts soft X-ray blackbody temperatures to the range 18-29 eV. The blackbody luminosity exceeds the hard X-ray luminosity by at least a factor of 4.5, but is of the same order as the optical/UV component. The soft X-ray (0.1-0.25 keV) and hard X-ray (1-6 keV) light curves covering almost two orbital periods are presented. (author)
High temperature materials technology research for advanced thermionic systems. Quarterly progress report for period ending September 30, 1993
Energy Technology Data Exchange (ETDEWEB)
Zee, R.H.; Rose, M.F.
Objective was to understand the strengthening mechanisms in advanced refractory alloys for high-temperature thermionic applications. During the first 6 months, the role of substitutional solutes in refractory alloy single crystals was identified and modeled using a simple size misfit factor as the governing parameter. During the past period, effort was concentrated on the strengthening effects in various refractory structures and the growth of refractory alloy single crystals. 11 figs, 4 tabs.
Logarithmic Expansions and the Stability of Periodic Patterns of Localized Spots for Reaction-Diffusion Systems in
Iron, David; Rumsey, John; Ward, Michael J.; Wei, Juncheng
The linear stability of steady-state periodic patterns of localized spots in for the two-component Gierer-Meinhardt (GM) and Schnakenberg reaction-diffusion models is analyzed in the semi-strong interaction limit corresponding to an asymptotically small diffusion coefficient of the activator concentration. In the limit , localized spots in the activator are centered at the lattice points of a Bravais lattice with constant area . To leading order in , the linearization of the steady-state periodic spot pattern has a zero eigenvalue when the inhibitor diffusivity satisfies for some independent of the lattice and the Bloch wavevector . From a combination of the method of matched asymptotic expansions, Floquet-Bloch theory, and the rigorous study of certain nonlocal eigenvalue problems, an explicit analytical formula for the continuous band of spectrum that lies within an neighborhood of the origin in the spectral plane is derived when , where is a detuning parameter. The periodic pattern is linearly stable when is chosen small enough so that this continuous band is in the stable left half-plane for all . Moreover, for both the Schnakenberg and GM models, our analysis identifies a model-dependent objective function, involving the regular part of the Bloch Green's function, that must be maximized in order to determine the specific periodic arrangement of localized spots that constitutes a linearly stable steady-state pattern for the largest value of . From a numerical computation, based on an Ewald-type algorithm, of the regular part of the Bloch Green's function that defines the objective function, it is shown within the class of oblique Bravais lattices that a regular hexagonal lattice arrangement of spots is optimal for maximizing the stability threshold in.
Mass distribution of particulates measured by Giotto's Dust Impact Detection System (DIDSY) in the close encounter period
Zarnecki, J. C.; Mcdonnell, J. A. M.; Burton, W. M.; Alexander, W. M.; Hanner, M. S.
The cumulative mass distribution of the comet Halley dust efflux in the close encounter period -300 to +300 sec was analyzed. Analysis of the cumulative mass distribution index (alpha) shows considerable short time scale variation. There is clear evidence from the flux rates of passage through at least one major dust enhancement (dust jet) just after closest approach and this is associated with a steepening of the alpha. Comparison with measurements from other sources, and with preencounter predictions, is also made.
Influence of dry period length on reproductive performance and productivity of Lacaune dairy sheep under an intensive management system.
Hernandez, Fernando; Elvira, Laura; Gonzalez-Martin, Juan-Vicente; Astiz, Susana
Intensive management is almost the only way to ensure dairy farm profitability. The dry period length (DPL) is a key factor in the productivity and health of dairy cows, but whether the same is true of dairy sheep is unclear. This study investigated the effects of DPL on the performance of Lacaune sheep under intensive management. We recorded 8136 lactations from 4220 ewes on one farm for the period 2005-2010, and data from a total of 6762 complete lactations 1-4 were included in the study. The length of the dry period following the current lactation was studied. The larger the total milk yield (MY) and daily milk yield (DMY), the shorter was the DPL before the next lactation. DPL correlated with MY (r=-0Ę384), DMY (r=-0Ę277) and the lambing-to-conception interval (LC; r=0Ę201, P120 d. P-DPL positively correlated with lambing-to-next conception interval (LNC; r=0Ę095, Pmilk yields (P-PDL-XS, 377▒215 l; P-PDL-l, 370▒168 l; P-PDL-XL, 396▒196 l). These yields were significantly lower than the yields for short and medium P-DPLs (P-DPL-S, 432▒187 l; P-DPL-M, 436▒191 l; Pyields in the next lactation. The best LNC was associated with the shortest Previous-DPL. Hence, 30-60 d should be the optimal dry period length for Lacaune sheep under intensive conditions. PMID:22850582
Hamiltonian of a many-electron system with single-electron and electron-pair states in a two-dimensional periodic potential
Hai, G. -Q.; Peeters, F.M.
Based on the metastable electron-pair energy band in a two-dimensional (2D) periodic potential obtained previously by Hai and Castelano [J. Phys.: Condens. Matter 26, 115502 (2014)], we present in this work a Hamiltonian of many electrons consisting of single electrons and electron pairs in the 2D system. The electron-pair states are metastable of energies higher than those of the single-electron states at low electron density. We assume two different scenarios for the singl...
A Time-Domain Asymptotic Approach to Predict Saddle-Node and Period Doubling Bifurcations in Pulse Width Modulated Piecewise Linear Systems
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El Aroudi A.
Full Text Available In this paper closed-form conditions for predicting the boundary of period-doubling (PD bifurcation or saddle-node (SN bifurcation in a class of PWM piecewise linear systems are obtained from a time-domain asymptotic approach. Examples of switched system considered in this study are switching dc-dc power electronics converters, temperature control systems and hydraulic valve control systems among others. These conditions are obtained from the steady-state discrete-time model using an asymptotic approach without resorting to frequency-domain Fourier analysis and without using the monodromy or the Jacobian matrix of the discrete-time model as it was recently reported in the existing literature on this topic. The availability of such design-oriented boundary expressions allows to understand the effect of the different parameters of the system upon its stability and its dynamical behavior.
Emergency orders in the periodic-review inventory system with fixed ordering costs and compound Poisson demand
DEFF Research Database (Denmark)
Johansen, Soren Glud; Thorstenson, Anders
Emergency orders have shorter lead times but incur extra costs compared to normal orders. We present a discrete-time Markov decision model where normal orders are issued according to a reorder point policy with a fixed order quantity, whereas emergency orders are controlled by a state-dependent reorder point policy with a target stock level. A rapid policy iteration algorithm is used to find and evaluate the policy that minimizes the long-run average cost per review period. In addition to fixed and variable costs for normal and emergency orders our model includes linear holding and backorder costs. The review period is of any given length. Neither the normal order nor the emergency order lead time are required to be integer multiples of the review period. The numerical study shows that the mixed policy found from our Markov decision model generally outperforms the best pure replenishment policy using either only normal or only emergency orders. Our model provides results that are similar to or slightly better than the results obtained with earlier models in the literature. Moreover, because our model accommodates compound Poisson demand, we are able to demonstrate that considerable cost reductions can then be obtained with the mixed policy when compared to the best pure replenishment policy. Finally, using sensitivity analysis we observe that a result on when a mixed policy is most beneficial, which has been found to hold for the simpler model without fixed ordering costs, seems to hold also for the more complex model that we investigate. (C) 2014 Elsevier B.V. All rights reserved.
Response of a hydrothermal system to magmatic heat inferred from temporal variations in the complex frequencies of long-period events at Kusatsu-Shirane Volcano, Japan
Nakano, M.; Kumagai, H.
We investigate temporal variations in the complex frequencies (frequency and quality factor Q) of long-period (LP) events that occurred at Kusatsu-Shirane Volcano, central Japan. We analyze LP waveforms observed at this volcano in the period between 1988 and 1995, which covers a seismically active period between 1989 and 1993. Systematic temporal variations in the complex frequencies are observed in October-November 1989, July-October 1991, and September 1992-January 1993. We use acoustic properties of a crack filled with hydrothermal fluids to interpret the observed temporal variations in the complex frequencies. The temporal variations in October-November 1989 can be divided into two periods, which are explained by a gradual decrease and increase of a gas-volume fraction in a water-steam mixture in a crack, respectively. The temporal variations in July-October 1991 can be also divided into two periods. These variations in the first and second periods are similar to those observed in November 1989 and in September-November 1992, respectively, and are interpreted as drying of a water-steam mixture and misty gas in a crack, respectively. The repeated nature of the temporal variations observed in similar seasons between July and November suggests the existence of seasonality in the occurrence of LP events. This may be caused by a seasonally variable meteoritic water supply to a hydrothermal system, which may have been heated by the flux of volcanic gases from magma beneath this volcano. ?? 2005 Elsevier B.V. All rights reserved.
Evolutionary outcomes for pairs of planets undergoing orbital migration and circularization: second-order resonances and observed period ratios in Kepler's planetary systems
Xiang-Gruess, M.; Papaloizou, J. C. B.
In order to study the origin of the architectures of low-mass planetary systems, we perform numerical surveys of the evolution of pairs of coplanar planets in the mass range (1-4) M?. These evolve for up to 2 ū 107 yr under a range of orbital migration torques and circularization rates assumed to arise through interaction with a protoplanetary disc. Near the inner disc boundary, significant variations of viscosity, interaction with density waves or with the stellar magnetic field could occur and halt migration, but allow circularization to continue. This was modelled by modifying the migration and circularization rates. Runs terminated without an extended period of circularization in the absence of migration torques gave rise to either a collision, or a system close to a resonance. These were mostly first order with a few per cent terminating in second-order resonances. Both planetary eccentricities were small Kepler observations. When circularization alone operates in the final stages, divergent migration occurs causing period ratios to increase. Depending on its strength the whole period ratio range between 1 and 2 can be obtained. A few systems close to second-order commensurabilities also occur. In contrast to when arising through convergent migration, resonant trapping does not occur and resonant angles circulate. Thus, the behaviour of the resonant angles may indicate the form of migration that led to near resonance.
The Experimental Plant and Modeling Method for Spatial Waves in Multicoupled Quasi-Optical Systems with Periodic Inhomogeneities
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G.S. Vorobjov
Full Text Available The experimental plant and the general method of modeling of electromagnetic wave processes in multicoupled quasi-optical systems are described. Examples of choosing the optimum regimes of modeling and basic parameters of the investigated electrodynamic systems are shown. The functional scheme of the experimental plant is also described. The general method of modeling of electromagnetic phenomena in resonant and waveguide multicoupled quasi-optical systems is presented for the first time.
Flow control by periodic devices: a unifying language for the description of traffic, production, and metabolic systems
International Nuclear Information System (INIS)
Metabolic systems need to show high performance under typical environmental conditions and, at the same time, maintain certain functions under a broad range of perturbations and varying conditions. It is precisely this robustness with respect to large environmental changes that makes metabolic networks a potentially very interesting role model for technical production and distribution systems. Here we develop a formalism to compare these systems and show that optimization strategies from one domain can also be successfully applied to the other domains
A neural circuit transforming temporal periodicity information into a rate-based representation in the mammalian auditory system
DEFF Research Database (Denmark)
Dicke, Ulrike; Ewert, Stephan D.
Periodic amplitude modulations AMs of an acoustic stimulus are presumed to be encoded in temporal activity patterns of neurons in the cochlear nucleus. Physiological recordings indicate that this temporal AM code is transformed into a rate-based periodicity code along the ascending auditory pathway. The present study suggests a neural circuit for the transformation from the temporal to the rate-based code. Due to the neural connectivity of the circuit, bandpass shaped rate modulation transfer functions are obtained that correspond to recorded functions of inferior colliculus IC neurons. In contrast to previous modeling studies, the present circuit does not employ a continuously changing temporal parameter to obtain different best modulation frequencies BMFs of the IC bandpass units. Instead, different BMFs are yielded from varying the number of input units projecting onto different bandpass units. In order to investigate the compatibility of the neural circuit with a linear modulation filterbank analysis asproposed in psychophysical studies, complex stimuli such as tones modulated by the sum of two sinusoids, narrowband noise, and iterated rippled noise were processed by the model. The model accounts for the encoding of AM depth over a large dynamic range and for modulation frequency selective processing of complex sounds.
Multiscale codes in the nervous system: the problem of noise correlations and the ambiguity of periodic scales.
Mathis, Alexander; Herz, Andreas V M; Stemmler, Martin B
Encoding information about continuous variables using noisy computational units is a challenge; nonetheless, asymptotic theory shows that combining multiple periodic scales for coding can be highly precise despite the corrupting influence of noise [Mathis, Herz, and Stemmler, Phys. Rev. Lett. 109, 018103 (2012)]. Indeed, the cortex seems to use periodic, multiscale grid codes to represent position accurately. Here we show how such codes can be read out without taking the long-term limit; even on short time scales, the precision of such codes scales exponentially in the number N of neurons. Does this finding also hold for neurons that are not firing in a statistically independent fashion? To assess the extent to which biological grid codes are subject to statistical dependences, we first analyze the noise correlations between pairs of grid code neurons in behaving rodents. We find that if the grids of two neurons align and have the same length scale, the noise correlations between the neurons can reach values as high as 0.8. For increasing mismatches between the grids of the two neurons, the noise correlations fall rapidly. Incorporating such correlations into a population coding model reveals that the correlations lessen the resolution, but the exponential scaling of resolution with N is unaffected. PMID:24032870
Integer sequences counting periodic points
Everest, Graham; Puri, Yash; Ward, Thomas
An existing dialogue between number theory and dynamical systems is advanced. A combinatorial device gives necessary and sufficient conditions for a sequence of non-negative integers to count the periodic points in a dynamical system. This is applied to study linear recurrence sequences which count periodic points. Instances where the $p$-parts of an integer sequence themselves count periodic points are studied. The Mersenne sequence provides one example, and the denominator...
Higher Education Enrollments and Student Success in Times of Budget Scarcity: Examining System-Level Impacts in Recessionary Periods
Wetstein, Matthew; Hays, Brianna; Nguyen, Alyssa
This study seeks to extend the literature on higher education enrollment patterns during times of recession by examining patterns of enrollment and successful course completion in one of the world's largest higher education systems--the California Community College system. The data are drawn from publicly available data sources on the web. CCCģ
5 CFR 9901.411 - Appraisal period.
...NATIONAL SECURITY PERSONNEL SYSTEM (NSPS) Performance Management ¦ 9901.411 Appraisal period. (a...an employee has not met the minimum period of performance, management may extend the appraisal period provided...
Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977
International Nuclear Information System (INIS)
Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested
Artificial heart development program. Volume II. System support. Phase III summary report. Period covered: July 1, 1973--September 30, 1977
Energy Technology Data Exchange (ETDEWEB)
Appendix A covers major activities of the Artificial Heart Development program that supported the design, fabrication, and test of the system demonstration units. Section A.1.0 provides a listing beyond that of the body of the report on the components needed for an implantation. It also presents glove box sterilization calibration results and results of an extensive mock circulation calibration. Section A.2.0 provides detail procedures for assembly, preparing for use, and the use of the system and major components. Section A.3.0 covers the component research and development activities undertaken to improve components of the existing system units and to prepare for a future prototype system. Section A.4.0 provides a listing of the top assembly drawings of the major systems variations fabricated and tested.
Forecasting the demand on solar water heating systems and their energy savings potential during the period 2001-2005 in Jordan
International Nuclear Information System (INIS)
Jordan is an example of a developing country that depends almost exclusively on imported oil. Luckily, Jordan is blessed with good solar energy resources. However, only 24% of Jordanian families are installing solar water heating systems (SWHS). The objective of this research is to forecast the yearly demand on SWHS by the household sector during the period 2001-2005 and to compute the potential energy savings throughout the investigated period due to the use of SWHS. It is found that the net energy collected over the entire investigated period is about 1454.4 million kW h. In addition, the capital savings over the entire investigated period is estimated to be 46.28 million US$ if SWHS are used to heat water instead of the commonly used LPG gas cookers. The results of the research may assist decision makers in the energy sector to implement more comprehensive plans that encourage more families to install SWHS and save on imported oil
Real working conditions and estimation on the rest time period of superheating system of the boiler OB 380 in TPP 'Oslomej' (Macedonia)
International Nuclear Information System (INIS)
In this paper, a residual life-time assessment of the 110 MW boiler reheater components is presented. Real operational conditions for each reheater component as a basis for the life-time assessment are experimentally determined with specially designed diagnostic and data acquisition system during five different regimes of boiler operation. According to determined operational conditions compared with the respective properties of reheater components, two main conclusions are done: (a) more than 60% of the real life-time is spent and (b) a shorter life-time than it is designed could be expected for the several components of reheater system. Taking these conclusions into account, a preposition of measures to be taken in order to obtain satisfied reliability of reheater system in the future period are recommended. One of proposed measures is to obtain respective monitoring equipment [12] for the boiler reheater system. (Author)
Ding, Yingchun; Zhang, Fengli; Chen, Zhaoyang; Lin, Chengyou; Yu, M Y
Random excitation of intense periodic highly-localized single-cycle light pulses in a stochastic background by continuous-wave stimulated Brillouin scattering in long optical fibers with weak feedback is found experimentally. Events with low period numbers are dominant and the optical feedback is crucial for the phenomenon. A three-wave coupling model for the phenomenon is proposed. The results are in good qualitative agreement with the observed phenomenon. The latter should be relevant to the understanding of similar rogue wave events in other nonlinear dissipative systems.
AltiKa: a Ka-band Altimetry Payload and System for Operational Altimetry during the GMES Period
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Jacques Verron
Full Text Available This paper describes the Ka-band altimetry payload and system that has beenstudied for several years by CNES, ALCATEL SPACE and some science laboratories.Altimetry is one of the major elements of the ocean observing system to be madesustainable through the GEOSS (Global Earth Observation System of Systems and GMES(Global Monitoring of the Environment and Security programs. A short review of somemission objectives to be fulfilled in terms of mesoscale oceanography in the frame of theGEOSS and GMES programs is performed. To answer the corresponding requirements, theapproach consisting in a constellation of nadir altimeter is discussed. A coupled Ka-bandaltimeter-radiometer payload is then described; technical items are detailed to explain howthis payload shall meet the science and operational requirements, and expectedperformances are displayed. The current status of the payload development and flightperspectives are given.
THE McDONALD OBSERVATORY PLANET SEARCH: NEW LONG-PERIOD GIANT PLANETS AND TWO INTERACTING JUPITERS IN THE HD 155358 SYSTEM
International Nuclear Information System (INIS)
We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) starsŚHD 79498, HD 155358, HD 197037, and HD 220773Śtaken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.
[Distribution of GABAergic neurons in pneumotaxic center nuclei in the early postnatal period in norm and in prenatal deficiency of serotoninergic system in rats].
The aim of this study was to determine the distribution of GABAergic neurons in pneumotaxic center structures (parabrachial complex medial subnucleus and K÷lliker-Fuse nucleus) in norm and in deficiency of serotoninergic system during the prenatal period of development in Wistar rats. Reduction of endogenous serotonin levels in fetal rats was achieved by tryptophan hydroxylase inhibition with para-chlorophenylalanine (PCPA), which was administered to female rats on Day 16 of gestation. Material was obtained from the area of the pons from experimental and control (intact) rat pups at early postnatal (Days 5, 10 and 12) and juvenile (Day 20) periods. At each time point, 5-6 animals were studied from both experimental and control groups. To demonstrate GABAergic neurons, antibodies against glutamate decarboxylase (GAD-67), the enzyme involved in its synthesis, were used. The results have shown that K÷lliker-Fuse nucleus contained a population of GABAergic neurons at early postnatal period, the size of which was preserved until juvenile age. In parabrachial complex medial subnucleus during the early postnatal period, a small number of GABAergic neurons was detected, which was somewhat increased by juvenile age. Serotonin deficiency in pneumotaxic center structures lead to a reduction of the numbers of GABAergic neurons, GABAergic synapses and their clusters. A reduction of serotonin levels during the prenatal period may cause the disturbances in the inhibitory afferent signaling of the pneumotaxic center nuclei and lead to the changes of local inhibitory GABAergic networks in its nuclei, resulting in the disturbances of the inhibitory processes in the center structures. PMID:25958722
Quantum 3D spin-glass system on the scales of space-time period of external electromagnetic field
International Nuclear Information System (INIS)
Full text: (author)The quantum 3D spin-glass system was investigated under the influence of external electromagnetic fields. Using Birgoff ergodic hypothesis the considered problem was reduced on two conditionally separable 1D problems. The first 1D problem describes N-body disordered quantum system on the space-time scales of external fields, with taking into account relaxation effects in the environment. Mathematically the problem is formulated in the limits of stochastic differential equation (SDE) for complex probabilistic processes. Using SDE type of Langevin-Schrodinger for the quantum distribution partial differential equation of second order is obtained. The second problem describes ensemble of 1D steric spin-chains with the certain length which are interacting randomly. For the description of this ensemble the system of the algebraic equations is obtained. These equations allows to build stable spin-chains and correspondingly to calculate statistical sum of ensemble at equilibrium. It is shown that combining of these two problems allows investigating 3D quantum spin-glass system along the external fields' propagation. In particular to investigate collective orientational effects which can leads to phase transitions of the first order and the order formation in disordered 3D quantum system
Periodic precursors of nonlinear dynamical transitions
International Nuclear Information System (INIS)
We study the resonant response of a nonlinear system to external periodic perturbations. We show by numerical simulation that the periodic resonance curve may anticipate the dynamical instability of the unperturbed nonlinear periodic system, at parameter values far away from the bifurcation points. In the presence of noise, the buried intrinsic periodic dynamics can be picked out by analyzing the system's response to periodic modulation of appropriate intensity
Energy transformation in molecular electronic systems: Research progress report for the period December 1, 1986-November 30, 1987
International Nuclear Information System (INIS)
The main research activity on our project continues to be the very active field of proton-transfer spectroscopy. Categories of research are: (1) Systematics of Proton-Transfer classes; (2) Picosecond Spectroscopy of Proton-Transfer in Lumichrome (a photolysis product of riboflavin); (3) Proton-Transfer Laser Research; (4) Computer Calculations on Proton-Transfer Systems; and (5) Unscheduled Research. New facets of the research program are: (1) Charge-Transfer (CT) Perturbation of Proton-Transfer Spectroscopy; (2) Super Computer Calculations on Proton-Transfer; (3) Dielectric Effects on Extended Dipoles in Proton-Transfer Spectroscopy; and (4) Proton-Transfer in Biological Systems
Autonomic adjusting of activity of cardio-vessel system of girls of the prepubescence period, engaged in dancing aerobic
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Romanchuk ?.P.
Full Text Available The vegetative adjusting of activity of the cardio-vessel system of girls is investigational. In an experiment took part girls of 9-12 years old. A type of sport is a dancing aerobics. The indexes of general power of spectrum of variability of cardiac rhythm are presented, systole and diastole arteriotony. Motion of the adaptation re-erecting is appraised under influence of the physical loadings in the conditions of current and operative control. Certain change activity and tone of vegetative influences on the cardio-vessel system. They determine the features of the further adaptation re-erecting in an organism.
Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems
International Nuclear Information System (INIS)
This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (¢COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed
Mercury distribution in abiotic and biological compartments within several estuarine systems from Argentina: 1980-2005 period.
De Marco, Silvia G; Bottķ, Sandra E; Marcovecchio, Jorge E
Total mercury contents from both abiotic and biological compartments within several estuaries from Argentina have been studied since the 1980s. The assessment of mercury occurrence in surface sediments, suspended particulate matter and crab and fish species from Mar Chiquita coastal lagoon, BahĒa Blanca estuary and Samboromb¾n Bay (in La Plata river estuary) are included in the present study. All samples were analyzed through Cold Vapor-Atomic Absorption Spectroscopy, following internationally standardized methods. In all cases analytical quality was checked against international reference materials. During the 1980s, Hg contents in sediments and SPM, as well as in edible fish species from BahĒa Blanca estuary were significantly higher (pMar Chiquita coastal lagoon and Samboromb¾n Bay have intermediate mercury levels in their biological compartments. In both cases, the possible occurrence of remote sources of this metal was considered. Even though, Hg values as determined in sediments and suspended particulate matter from Samboromb¾n Bay were the highest ones for the whole analyzed period. Both mercury bioaccumulation and biomagnification processes were evaluated in the studied estuaries, as well as the potential qualification of estuarine foodstuffs for human consumption. PMID:16624373
Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems
Directory of Open Access Journals (Sweden)
Saikat Dutta
Full Text Available This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs functionalized with carboxylic acid (¢COOH group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.
Effect of carboxylic acid of periodic mesoporous organosilicas on the fructose-to-5-hydroxymethylfurfural conversion in dimethylsulfoxide systems
Energy Technology Data Exchange (ETDEWEB)
Dutta, Saikat; Wu, Kevin C.-W., E-mail: firstname.lastname@example.com, E-mail: firstname.lastname@example.com [Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Kao, Hsien-Ming, E-mail: firstname.lastname@example.com, E-mail: email@example.com [Department of Chemistry, National Central University, Chung-Li 32054, Taiwan (China)
This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (¢COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and {sup 13}C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed.
Numerical Simulation of Exhaust Gas Cooling in Channels with Periodic Elbows for Application in Compact Heat Recovery Systems
Di Bari, Sergio; Cotton, James S.; Robinson, Anthony J.
Miniature and Micro devices represent the new frontier for advanced heat and mass transfer technology. Due to the small length scales, the use of CFD is very useful for designing and optimizing microfluidic devices since experimentation and visualization at these scales can be difficult. In this work a high temperature air microfluidic cooling strategy for applications such as compact waste heat recovery, exhaust gas recirculation and fuel cell thermal management is proposed. Initially, the application of a simple straight microchannel is considered. In an effort to partially compensate for the poor thermal properties of air, right-angle bends are introduced in order to induce Dean vortices which periodically restart the thermal boundary layer development, thus improving the heat transfer and fluid mixing. Numerical simulations in the range of 100 <= ReDh <= 1000 have been carried out for channels of square cross-section. Channel wall lengths of 1.0 mm are investigated for elbow spacings of 5 mm, 10 mm and 15 mm. High temperature air (300░C) at atmospheric inlet pressure is the working fluid. The results indicate that the elbows substantially improve the local and average heat transfer in the channels while increasing the pressure drop. Design considerations are discussed which take into account the heat transfer and pressure drop characteristics of the channels.
Optimal unit commitment of the power system in Bulgaria during the transitional period to power wholesale market (cont..)
International Nuclear Information System (INIS)
The first part of the parer considers the general problem of optimal yearly unit commitment in the new economical conditions in Bulgaria. The second part deals with non-convex problem , taking into account some costs for starting and stopping of power systems. The transition from yearly commitment to weekly or daily dispatching is commented
Motion Systems Role in Flight Simulators for Flying Training. Final Report for Period June 1977-June 1978.
Cyrus, Michael L.
This report reviews the literature as it relates to the use of platform motion systems in flight simulators for flying training. Motion is discussed in terms of its effect on compensatory, pursuit, and precognitive tasks, within both the simulator and transfer contexts. Although both skilled and unskilled behaviors are addressed, the former areģ
Interactions Between Moderate- and Long-Period Giant Planets: Scattering Experiments for Systems in Isolation and with Stellar Flybys
Boley, Aaron C; Ford, Eric B
The chance that a planetary system will interact with another member of its host star's nascent cluster would be greatly increased if gas giant planets form in situ on wide orbits. In this paper, we explore the outcomes of planet-planet scattering for a distribution of multiplanet systems that all have one of the planets on an initial orbit of 100 AU. The scattering experiments are run with and without stellar flybys. We convolve the outcomes with distributions for protoplanetary disk and stellar cluster sizes to generalize the results where possible. We find that the frequencies of large mutual inclinations and high eccentricities are sensitive to the number of planets in a system, but not strongly to stellar flybys. However, flybys do play a role in changing the low and moderate portions of the mutual inclination distributions, and erase dynamically cold initial conditions on average. Wide-orbit planets can be mixed throughout the planetary system, and in some cases, can potentially become hot Jupiters, whi...
Nutritional restriction of omega-3 fatty acids alters topographical fine tuning and leads to a delay in the critical period in the rodent visual system.
de Velasco, Patricia Coelho; Mendonńa, Henrique Rocha; Borba, Juliana Maria Carrazzone; Andrade da Costa, Belmira Lara da Silveira; Guedes, Rubem Carlos Araujo; Navarro, Daniela Maria do Amaral Ferraz; Santos, Geanne Karla Novais; Faria-Melibeu, Adriana da Cunha; Campello Costa, Paula; Serfaty, Claudio Alberto
The development and maturation of sensory systems depends on the correct pattern of connections which occurs during a critical period when axonal elimination and synaptic plasticity are involved in the formation of topographical maps. Among the mechanisms involved in synaptic stabilization, essential fatty acids (EFAs), available only through diet, appear as precursors of signaling molecules involved in modulation of gene expression and neurotransmitter release. Omega-3 fatty acids, such as docosahexaenoic acid (DHA), are considered EFAs and are accumulated in the brain during fetal period and neonatal development. In this study, we demonstrated the effect of omega-3/DHA nutritional restriction in the long-term stabilization of connections in the visual system. Female rats were fed 5 weeks before mating with either a control (soy oil) or a restricted (coconut oil) diet. Litters were fed until postnatal day 13 (PND13), PND28 or PND42 with the same diets when they received an intraocular injection of HRP. Another group received a single retinal lesion at the temporal periphery at PND21. Omega-3 restriction induced an increase in the optical density in the superficial layers of the SC, as a result of axonal sprouting outside the main terminal zones. This effect was observed throughout the SGS, including the ventral and intermediate sub-layers at PND13 and also at PND28 and PND42. The quantification of optical densities strongly suggests a delay in axonal elimination in the omega3(-) groups. The supplementation with fish oil (DHA) was able to completely reverse the abnormal expansion of the retinocollicular projection. The same pattern of expanded terminal fields was also observed in the ipsilateral retinogeniculate pathway. The critical period window was studied in lesion experiments in either control or omega-3/DHA restricted groups. DHA restriction induced an increased sprouting of intact, ipsilateral axons at the deafferented region of the superior colliculus compared to the control group, revealing an abnormal extension of the critical period. Finally, in omega-3 restricted group we observed in the collicular visual layers normal levels of GAP-43 with decreased levels of its phosphorylated form, p-GAP-43, consistent with a reduction in synaptic stabilization. The data indicate, therefore, that chronic dietary restriction of omega-3 results in a reduction in DHA levels which delays axonal elimination and critical period closure, interfering with the maintenance of terminal fields in the visual system. PMID:22227060
A Fortran 90 Hartree-Fock program for one-dimensional periodic $\\pi$-conjugated systems using Pariser-Parr-Pople model
Gundra, Kondayya
Pariser-Parr-Pople (P-P-P) model Hamiltonian is employed frequently to study the electronic structure and optical properties of $\\pi$-conjugated systems. In this paper we describe a Fortran 90 computer program which uses the P-P-P model Hamiltonian to solve the Hartree-Fock (HF) equation for infinitely long, one-dimensional, periodic, $\\pi$-electron systems. The code is capable of computing the band structure, as also the linear optical absorption spectrum, by using the tight-binding (TB) and the HF methods. Furthermore, using our program the user can solve the HF equation in the presence of a finite external electric field, thereby, allowing the simulation of gated systems. We apply our code to compute various properties of polymers such as $trans$-polyacetylene ($t$-PA), poly-\\emph{para}-phenylene (PPP), and armchair and zigzag graphene nanoribbons, in the infinite length limit.
On the rotation periods of the components of the triple system TYC9300-0891-1AB/TYC9300-0529-1 in the Octans Association
Messina, Sergio; Worters, Hannah L; Bromage, Gordon E; Sanchez, Richardo Zanmar
Stellar rotation depends on different parameters. The range of values of these parameters causes the dispersion in the rotation period distributions observed in young stellar clusters/associations. We focus our investigation on the effects of different circumstellar environments on stellar rotation. More specifically, we are searching in stellar Associations for visual triple systems where all stellar parameters are similar, with the only exceptions of the unknown initial rotation period, and of the circum-stellar environment, in the sense that one of the two about equal-mass components has a close-by third 'perturber' component. In the present study we analyse the 35-Myr old visual triple system TYC 9300-0891-1AB + TYC 9300-0529-1 in the young Octans stellar association consisting of three equal-mass K0V components. We collected from the literature all information that allowed us to infer that the three components are actually physically bound forming a triple system and are members of the Octans Association...
Characterization of Peaks and Valleys of Electricity Demand. Application to the Spanish Mainland System in the Period 2000-2020
FermĒn Moreno
Energy planning must anticipate the development and strengthening of power grids, power plants construction times, and the provision of energy resources with the aim of increasing security of supply and its quality. This work presents a methodology for predicting power peaks in mainland SpainÆs system in the decade 2011-2020. Forecasts of total electricity demand of Spanish energy authorities set the boundary conditions. The accuracy of the results has successfully been compared with record...
Endometrial vessel maturation in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time
Ravet, Stķphanie; Labied, Soraya; Blacher, Silvia; Frankenne, Francis; Munaut, Carine; Fridman, Viviana; Beliard, Aude; Foidart, Jean-Michel; Nisolle, Michelle
BACKGROUND: Levonorgestrel-releasing intrauterine system (LNG-IUS), although inserted to reduce heavy menstruation, causes irregular early transient bleeding. The objective of the study was to document quantitative changes in endometrial vessels of short- ( or =12 months) LNG users. The area, density and maturation of endometrial vessels were quantified in 19 endometrial biopsies of women with LNG-IUS and in 10 normally ovulating patients during mid-luteal phas...
A bacteria foraging algorithm for solving integrated multi-period cell formation and subcontracting production planning in a dynamic cellular manufacturing system
Scientific Electronic Library Online (English)
S.H., Tang; H., Nouri; O., Motlagh.
Full Text Available The bacteria foraging algorithm (BFA) is a new computation technique inspired by the social foraging behaviour of Escherichia coli (E. coli) bacteria. Since the introduction of the BFA by Kevin M. Passino, there have been many challenges in employing this algorithm to problems other than those for w [...] hich the algorithm was proposed. This research aims to apply this emerging optimisation algorithm to develop a mixed-integer programming model for designing cellular manufacturing systems (CMSs), and production planning in dynamic environments. In dynamic environments, product mix and part demand vary under multi-period planning horizons. Thus the best-designed cells for one period may not be adequate for subsequent periods, requiring their reconstruction. The advantages of the proposed model are as follows: consideration of batch inter-cell and intra-cell material handling by assuming the sequence of operations, allowing for alternative process plans for part types, and consideration of machine copying, with an emphasis on the effect of trade-offs between production and outsourcing costs. The goal is to minimise the sum of the machines' constant and variable costs, inter-cell and intra-cell material handling costs, reconstruction costs, partial subcontracting costs, and inventory carrying costs. In addition, a newly-developed BFA-based optimisation algorithm has been compared with the branch and bound algorithm. The results suggest that the proposed algorithm performs better than related works.
The HARPS search for southern extra-solar planets XXXVI: Five new long-period giant planets and a system update
Moutou, C; Mayor, M; Bouchy, F; Benz, W; Lovis, C; Naef, D; Pepe, F; Queloz, D; Santos, N C; Segransan, D; Sousa, S G; Udry, S
We describe radial-velocity time series obtained by HARPS on the 3.60 m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD-114672. Their periods range from 492 to 1684 days, semi-major axes range from 1.2 to 2.69 AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5 Mjup. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663+-8 and 1818+-25 days, orbital eccentricities of 0.14+-0.08 and 0.20+-0.04, and minimum masses of 0.36+-0.04 and 0.93+-0.06 Mjup. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557+-0.0001 days and a minimum mass of 0.62+-0.025 Mjup. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet s...
Controls on geyser periodicity.
Ingebritsen, S E; Rojstaczer, S A
Geyser eruption frequency is not constant over time and has been shown to vary with small (geyser system is approximated as a permeable conduit of intensely fractured rock surrounded by a less permeable rock matrix. Numerical simulation of this conceptual model yields a set of parameters that controls geyser existence and periodicity. Much of the responsiveness to remote seismicity and other small strains in the Earth can be explained in terms of variations in permeability and lateral recharge rates. PMID:17757358
Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells : 12 Month Periodic Activity Report
DEFF Research Database (Denmark)
Jensen, Jens Oluf; Li, Qingfeng
Polymer electrolyte membrane fuel cell (PEMFC) technology based on Nafion membranes can operate at temperatures around 80░C. The new development in the field is high temperature PEMFC for operation above 100░C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new technology have been identified, and new concepts and solutions have been provisionally identified. FURIM is directed at tackling these key issues by concentrating on the further materials development, compatible technologies, and system integration of the high temperature PEMFC. The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer, afterburner and power management system, that are compatible with the HT-PEMFC; and (3) integration of the HT-PEMFC stack with these compatible subunits. The main goal of the project is a 2kWel HT-PEMFC stack operating in a temperature range of 120-220░C, with a single cell performance target of 0.7 A/cm▓ at a cell voltage around 0.6 V. The target durability is more than 5,000 hours. A hydrocarbon reformer and a catalytic burner are to be developed and integrated with the stack. The key issue of the project is development and improvement of the temperature-resistant polymer membranes with respect to durability, conductivity, mechanical and other properties. For this purpose, basic polymers will be first synthesized and optimized. Different routes to functionalize the polymers will be explored to increate proton conductivity. By the development of advanced materials, demonstration of the high temperature PEMFC stack and integration of such a system, FURIM is expected to sufficiently promote the commercialisation of the fuel cell technology for both vehicle propulsion and stationary applications.
Fusion reactor systems studies. Progress report for the period November 1, 1996--October 31, 1997, and final report
International Nuclear Information System (INIS)
During FY97, the University of Wisconsin Fusion Technology Institute personnel have participated in the ARIES-RS and the ARIES-ST projects. The main areas of effort are: (1) neutronics analysis; (2) shielding of components and personnel; (3) neutron wall loading distribution; (4) radiation damage to in-vessel components; (5) components lifetimes; (6) embrittled materials designs issues; (7) stress and structural analysis; (8) activation, LOCA, and safety analysis; (9) support and fabrication of components; (10) vacuum system; and (11) maintenance. Progress made in these areas are summarized
Four-day incubation period for blood culture bottles processed with the Difco ESP blood culture system.
Doern, GV; Brueggemann, AB; Dunne, WM; Jenkins, SG; Halstead, DC; McLaughlin, JC
Blood culture records from 1994 to 1995 from five U.S. medical centers all using the Difco ESP continuous monitoring blood culture system were reviewed retrospectively. Among a total of 7,362 isolates of bacteria and yeasts, only 0.1% of possibly significant isolates would have been missed had blood cultures been routinely incubated for 4 days instead of the 5 days recommended by the manufacturer. Conversely, numerous contaminants, detected only on day 5, would have been eliminated by a 4-day...
Efficient integration of renewable energy into future energy systems. Development of European energy infrastructures in the period 2030 to 2050
Energy Technology Data Exchange (ETDEWEB)
Funk, Carolin; Uhlig, Jeanette; Zoch, Immo (eds.)
In consideration of strategic climate mitigation, energy security and economic competitiveness goals, the EU passed the Directive 2009/28/EC, including a binding target of 20 per cent renewable energy consumption in the EU by 2020. This target is comprehensive and includes energy generation, transport, heating and cooling sectors. In 2008, renewable energy consumption in the EU was about 10 per cent. So meeting the 20 per cent renewable energy objective will require massive changes in energy production, transmission and consumption in the EU. Furthermore, it is obvious that the development of the energy system will not stop in 2020, but that it will continue towards 2050 and beyond. Over the past century, the European electricity system was developed in line with a national utilit y perspective which heavily emphasised large, centralised conventional power production. Investment decisions for new energy infrastructure and technology were typically made at the national level. In the future, much more energy production will be based on local or regional renewable energy sources (RES). Many consumers may also become energy producers feeding into the infrastructures. Transnational energy transfers will gain in importance. These changes will require very different electricity and gas infrastructures and decision-making processes from today. Lack of infrastructure capacity is already a barrier for the further deployment of RES-based energy production in some regions in Europe. (orig.)
The National Dose Registration and Information System: Dose distributions in the Netherlands over the period 1989-1993
International Nuclear Information System (INIS)
In 1988 the Ministry of Social Affairs and Employment commissioned TNO Radiological Service to set up a National Dose REgistration and Information System (NDRIS). The government had three reasons in view to build NDRIS: To improve radiation protection by supervising the occupational doses of radiation workers by using one central database system; To improve the reliability of long term storage of dose data; To improve the possibilities for statistical analysis of occupational doses to guide policy making. Each approved dosimetry service (ADS) in the country sends its dose information to NDRIS on a monthly basis. IN its turn NDRIS sends back for each worker monitored by that ADS, the integrated dose as measured by any ADS. This creates the possibility for each ADS to report to the workers their total annual dose irrespectively whether they work for more than one employer or are monitored by more than one ADS, either simultaneously or successively in the course of the year. European legislation requires that the occupational dose should be controlled in this way. The availability of the centralized database replaces the need of a radiation passbook for national use. The passbook that is needed by radiation workers during interstate travelling can be produced using data from NDRIS
Spoken Language Dialogue Systems and Components Best practice in development and evaluation (DISC 24823) - Periodic Progress Report 1
Bernsen, N O; Bernsen, Niels Ole; Dybkjaer, Laila
The DISC project aims to (a) build an in-depth understanding of the state-of-the-art in spoken language dialogue systems (SLDSs) and components development and evaluation with the purpose of (b) developing a first best practice methodology in the field. The methodology will be accompanied by (c) a series of development and evaluation support tools. To the limited extent possible within the duration of the project, the draft versions of the methodology and the tools will be (d) tested by SLDS developers from industry and research, and will be (e) packaged to best suit their needs. In the first year of DISC, (a) has been accomplished, and (b) and (c) have started. A proposal to complete the work proposed above by adding 12 months to the 18 months of the present project, has been submitted to Esprit Long-Term Research in March 1998.
Regional ceramic production and distribution systems during the late intermediate ceramic period in central Chile based on NAA
International Nuclear Information System (INIS)
This research focused on the pre-Hispanic ceramic production and distribution systems of the Maipo region in central Chile by means of determining the concentration of the chemical elements in pottery of the Aconcagua culture (900-1450 A.D.) with instrumental neutron activation analysis (INAA). Pottery fragments from eight archaeological sites and natural clays from the study region were included. The differences in chemical composition between subsets of the sample (sites, paste group and ceramic type) were interpreted as indicators of resource and ceramic production locations as well as the imprint of the geological background. These results contributed to the understanding of the Aconcagua ceramic assemblage and helped to test some hypotheses about the Aconcagua social organization. (author)
Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells : 24 Month Periodic Activity Report
DEFF Research Database (Denmark)
Li, Qingfeng; Jensen, Jens Oluf
The new development in the field of polymer electrolyte membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100░C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new technology have been identified, and new concepts and solutions have been provisionally identified. FURIM is directed at tackling these key issues by concentrating on the further materials development, compatible technologies, and system integration of the high temperature PEMFC. The strategic developments of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3) integration of the HT-PEMFC stack with these compatible subunits. The main goal of the project is a 2kWel HT-PEMFC stack operating in a temperature range of 150-200░C, with a single cell performance target of 0.7 A/cm▓ at a cell voltage around 0.6 V. The target durability is more than 5,000 hours. A hydrocarbon reformer and a catalytic burner are to be developed and integrated with the stack. The key issue of the project is development and improvement of the temperature-resistant polymer membranes with respect to durability, conductivity, mechanical and other properties. For this purpose, basic polymers will be first synthesized and optimized. Different routes to functionalize the polymers will be explored to increate proton conductivity. By the development of advanced materials, demonstration of the high temperature PEMFC stack and integration of such a system, FURIM is expected to sufficiently promote the commercialisation of the fuel cell technology for both vehicle propulsion and stationary applications.
... one of these changes. What is a menstrual period? When puberty begins, your brain signals your body ... called ōyour periodö). When will I start my period? Most girls start their periods between the ages ...
Comparative study of different systems for trapping the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), in Morocco over the period 1987-1991
International Nuclear Information System (INIS)
In an effort to standardize the trapping of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), a comparative study of various types of traps and attractants was carried out in the Souss region of Morocco over a five-year period (1987-1991) for the purpose of detecting the medfly. Nineteen trapping systems were tested - nine dry traps and ten wet. Under the conditions in the region the dry traps proved very effective in trapping medflies, in particular males. The Maghrebmed dry trap performed best, followed by the Hawaiian dry trap and the Nadel trap. The IPMT with a food bait (Nulure + borax) and a sex attractant (trimedlure), although a wet trap, proved as attractive to male flies as the first two dry traps just mentioned. Among the wet traps, McPhail systems baited with Nulure and borax proved highly attractive to female medflies. (author). 16 refs, 5 figs, 9 tabs
UBVR-photometry of the CQ Cep system, the change of the period and mass loss of the Wolf-Rayet star
International Nuclear Information System (INIS)
The new photoelectric UBVR-observations have been obtained for the eclipsing binary system CQ Cep (WN7+O7, p=1sup(d), 641246). These observations, together with all published photographic and photoelectric data from 1899 to 1981, allow to find out change (decreasing) of the period for the system CQ Cep: t=(-0.019+-0.006) s/yr. The rate of the matter outflow from the star WN7 to the companion star 07 is greater than (0.69+-0.22)x10-5 M/yr., where M is the mass of the Sun One may expect the mass loss rate for the separate star WN7 to be close to 10-5 M/yr
Many-body calculations of low-energy eigenstates in magnetic and periodic systems with self-healing diffusion Monte Carlo: steps beyond the fixed-phase
Reboredo, Fernando AgustĒn
The self-healing diffusion Monte Carlo algorithm (SHDMC) [Reboredo, Hood and Kent, Phys. Rev. B {\\bf 79}, 195117 (2009); Reboredo, {\\it ibid.} {\\bf 80}, 125110 (2009)] is extended to study the ground and excited states of magnetic and periodic systems. The method converges to exact eigenstates as the statistical data collected increases if the wave function is sufficiently flexible. A recursive optimization algorithm is derived from the time evolution of the mixed probability density, which is given by an ensemble of electronic configurations (walkers) with complex weight. This complex weight allows the amplitude of the fixed-node wave function to move away from the trial wave function phase. This novel approach is both a generalization of SHDMC and the fixed-phase approximation [Ortiz, Ceperley and Martin, Phys Rev. Lett. {\\bf 71}, 2777 (1993)]. When used recursively it simultaneously improves the node and the phase. The algorithm is demonstrated to converge to nearly exact solutions of model systems with pe...
Hot subdwarf binaries from the MUCHFUSS project - Analysis of 12 new systems and a study of the short-period binary population
Kupfer, T; Heber, U; žstensen, R H; Barlow, B N; Maxted, P F L; Heuser, C; Schaffenroth, V; Gõnsicke, B T
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M>1.0 M$_\\odot$), neutron stars, or stellar-mass black holes. We present orbital and atmospheric parameters and put constraints on the nature of the companions of 12 close hot subdwarf B star (sdB) binaries found in the course of the MUCHFUSS project. The systems show periods between 0.14 and 7.4 days. Three systems most likely have white dwarf companions. SDSS J083006.17+475150.3 is likely to be a rare example of a low-mass helium-core white dwarf. SDSS J095101.28+034757.0 shows an excess in the infrared that probably originates from a third companion in a wide orbit. SDSS J113241.58-063652.8 is the first helium deficient sdO star with a confirmed close companion. This study brings to 142 the number of sdB binaries with orbital periods of less than 30 days and with measured mass functions. We present an analysis of the minimu...
Feeding systems and periods of finishing on the body and carcass measurements of lambs slaughtered in the South Central region of the Paranß
Directory of Open Access Journals (Sweden)
Odilei Rogerio Prado
Full Text Available The objective was to determine the effect of feeding system and time of the year on the in vivo and carcass characteristics of lambs slaughtered at the Cooperative Cooperalianńa (Guarapuava-PR. Ile de France lambs and their crossbreds (n=253 were evaluated at slaughter with 39.6 kg of mean body weight in three periods between April and September 2010. Four feeding systems for finishing of lambs were identified: a grazing dams + lambs with creep-feeding for lambs (n=67; b no supplemented, grazing dams + lambs (n=47; c grazing dams + lambs, all of them supplemented with concentrate (n=30; d irregular system of feeding (n=109. Measurements on lambs were carried out in vivo and by ultrasound before slaughter and the carcass measurements were taken before and after chilling. Lambs delivered for slaughter between the end of August and the first half of September showed better results (p <0.05 for muscle development, dressing percentage and fat thickness in the carcass compared to that slaughtered in April and June. It was concluded that the feeding system with supplementation for dams and sucking lambs resulted in better characteristics for body and carcass measurements compared to other systems.
A study on the optimized fuel cycle systems during the transition period from LWR era to FBR era
International Nuclear Information System (INIS)
This paper mentions a preliminary evaluation on the typical LWR-to-FBR transition scenarios. Deployment rate of FBRs is strongly connected with replacement rate of LWRs, however, the transition should also be seen as a matter of the optimization of fuel cycle systems. Based on the Pu balance evaluation, it seems definitely necessary to save an adequate amount of LWR spent fuels before beginning the deployment of FBRs. The mission of the second LWR fuel reprocessing plant in Japan will be to feed Pu needed for starting up new FBRs. Along with the Pu utilization, especially as LWR-MOX fuel, the accumulation of minor actinides (MAs) in the high-level radioactive waste (HLW) will become dominant and finally result in larger number of vitrified HLW because of heat generation from MAs. MA recovery cycle combined with the FBR will give successful solution on this matter. Requirements on the next generation reprocessing plant, which corresponds to the transition scenario, are studied and innovative concept named 'PEACE' is proposed. (author)
On the quantum effects on noncollinear Lagrangian points and displaced periodic orbits in the Earth-Moon system
Battista, Emmanuele; Esposito, Giampiero; Simo, Jules
Recent work in the literature has shown that the leading long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics, i.e., at the Lagrangian libration points of stable equilibrium the planetoid is not exactly at equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we discuss the prospects to measure, with the help of laser ranging, the above departure from the equi...
Characterization of Peaks and Valleys of Electricity Demand. Application to the Spanish Mainland System in the Period 2000-2020
Directory of Open Access Journals (Sweden)
FermĒn Moreno
Full Text Available Energy planning must anticipate the development and strengthening of power grids, power plants construction times, and the provision of energy resources with the aim of increasing security of supply and its quality. This work presents a methodology for predicting power peaks in mainland SpainÆs system in the decade 2011-2020. Forecasts of total electricity demand of Spanish energy authorities set the boundary conditions. The accuracy of the results has successfully been compared with records of demand (2000-2010 and with various predictions published. Three patterns have been observed: 1 efficiency in the winter peak; 2 increasing trend in the summer peak; 3 increasing trend in the annual valley of demand. By 2020, 58.1 GW and 53.0 GW are expected, respectively, as winter and summer peaks in a business-as-usual scenario. If the observed tendencies continue, former values can go down to 55.5 GW in winter and go up to 54.7 GW in summer. The annual minimum valley of demand will raise 5.5 GW, up to 23.4 GW. These detailed predictions can be very useful to identify the types of power plants needed to have an optimum structure in the electricity industry.
The phase equilibria and thermal stability of the long-period stacking ordered phase in the Mg¢Cu¢Y system
International Nuclear Information System (INIS)
Highlights: Ģ 14H LPSO structure has been confirmed to be stable in the Mg¢Cu¢Y system. Ģ Partial isothermal sections of the Mg¢Cu¢Y system from 300 to 450 ░C have been established. Ģ Reaction L + ?-Mg ? 14H + Mg2Cu has been determined in the Mg¢Cu¢Y system. Ģ The thermal stability of the 14H phase in the Mg¢Cu¢Y system has been well studied. - Abstract: Phase equilibria in the Mg-rich Mg¢Cu¢Y system at 300, 400 and 450 ░C have been experimentally investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), electron probe micro-analyzer (EPMA) and transmission electron microscope (TEM). The results show that a long-period stacking ordered (LPSO) phase 14H is stable in the Mg¢Cu¢Y system, which is the only one ternary intermetallic compound that gets a thermodynamic equilibrium with the a-Mg phase. The equilibrium 14H phase has a very limited solid solution range, and can be nearly regarded as a ternary stoichiometric compound with a formulae as Mg91Cu4Y5. The thermal stability of the 14H phase in the Mg¢Cu¢Y system has been well studied, which shows that the 14H phase disappears varying from 442 ░C to 490 ░C depending on the alloy composition. The isothermal sections of the Mg-rich Mg¢Cu¢Y system at 300, 400 and 450 ░C have been finally established, and moreover, a quasi-peritectic reaction L + ?-Mg ? 14H + Mg2Cu has been determined occurring at 442 ░C with an estimated liquid composition of Mg77Cu18Y5
A Multi-Layer Phoswich Radioxenon Detection System, Reporting Period 07/01/07 - 09/30/07
International Nuclear Information System (INIS)
During this quarter, the detector manufacturer (Saint-Gobain) delivered one side of the prototype two-channel phoswich detector (XEPHWICH). Once received, our Digital Pulse Processor (DPP1, 12-bit/100 MHz) was employed to capture and digitally process phoswich pulses from laboratory radioactive sources. Our previous pulse shape discrimination algorithm was modified by utilizing three trapezoidal digital filters. This algorithm provides a two-dimensional plot in which the pulse shapes of interest are classified and then can be well identified. The preliminary experimental results will be presented at the 2007 Informal Xenon Monitoring Workshop. The DPP2 (two-channel, 12-bit/ 250 MHz Digital Pulse Processor) is at the prototyping stage. The analog sections have been designed, prototyped and tested. A 6-layer Printed Circuit Board (PCB) was designed, ordered and delivered. The board components were ordered and are now being assembled and examined for proper functionality. In addition, the related FPGA hardware description code (using VHDL) is under development and simulation. Additionally, our researchers have been studying materials regarding wavelet transforms for incorporation into the project. Wavelet transform is an interesting tool for signal processing; one use for our purpose would be to de-noise the detector signal and to express the signal in a few coefficients for signal compression and increased speed. Light capture efficiency modeling and analysis was performed on the XEPHWICH design. Increased understanding of the modeling software was obtained by the discovery of a bug and successful workaround techniques with the DETECT2000 software. Further modeling and plot generation experience was had by the continued use of CERN's ROOT and GEANT4 software packages. Simulations have been performed to compare the output of points versus planes in light capture efficiency. An additional simulation was made with a runtime that was an order-of-magnitude greater than previous simulations, to confirm convergence of the solutions provided by our software methods. We have initiated our investigation into the radon signature expected in our XEPHWICH system. We intend to utilize this signature to confirm earth movement, in the event of an underground nuclear explosion, by continuously monitoring radon levels and noting increases in radon concentration in conjunction with increased levels of radioxenons. The research group is also designing and constructing a fission chamber to be used for the collection of radioxenon gases following neutron bombardment of HEU in the Oregon State University TRIGA reactor. To this point, we have completed milling the aluminum housing and have modeled fission product nuclide production associated with the fissioning of HEU. Additionally, the students have been busy compiling the appropriate information in preparation for irradiation approvals. Using beta spectra of three initial nuclides collected on the prototype phoswich detector, spectral identification by a preliminary neural network was compared to that of solvers of a linear system of equations. Pre-processing in areas such as smoothing and endpoint identification is also being investigated as a means of improving spectral identification
[The effect of system restructuring on absenteeism due to sickness in the work place. I. Sickness absenteeism during the period 19989-1994].
Szubert, Z; Sobala, W; Zyci?ska, Z
The current transformation of property relations and economic restructuring, along with many other factors, influence the health condition of workers. The objective of the study was to illustrate the size of the problem and to identify the major causes of work disability among persons employed in enterprises undergoing those processes during the years 1989-94 against the situation observed in the whole country during the same period. The study was carried out in one of the largest industrial plants undergoing the process of economic restructuring. The group investigated was composed of 8,588 workers (including 62.6% of males). In individual years the number of workers in this group was decreasing, and in 1994 the employment status in the group accounted for 37% in relation to the number of workers employed during the first year under observation. The analysis of work disability was based on the rate of sickness absenteeism calculated as a relationship between the number of days of work disability and the number of working days during that particular period. Due to the application of this method it was feasible to consider both workers employed and persons who left the plant, regardless of their employment duration during a year. The study showed a 20 per cent increase in sickness absenteeism during the period of 1989-94. The highest rate (8.60) was noted in 1994. It was higher by 16% in comparison to the rate for the whole country. The greatest difference between these rates was observed in 1990 (the rate in the group investigated was higher by 46%). As to the causes of work disability, the main differences concerned two categories of illnesses, diseases of the circulatory system, a major cause of sickness absenteeism in the group studied (21%), and diseases of the musculoskeletal system, a major cause of sickness absenteeism in Poland. The change in the relationship between sickness absenteeism and the age during the period of the plant restructuring resulted from the fact that a large number of workers left the job. It was observed that the rate of the sickness absenteeism was almost directly proportional to the percentage of persons leaving the plant in individual years. The study showed that changes in the size and the structure of employment resulting from the plant restructuring influence the level of sickness absenteeism, and the age-related diversification in causes of diseases, and in consequence alter the established regularities. PMID:9501337
A phase space formulation of quantum mechanics for systems with periodic boundary conditions, and application to a one-dimensional hard sphere system
International Nuclear Information System (INIS)
The Wigner-Weyl formalism for spatially illimited systems is modified to be applicable to systems enclosed in a massles rigid and freely moving box. The formalism is then applied to a one-dimensional model gas or liquid consisting of two and three hard spheres respectively. Velocity correlation functions and their classical limits are calculated. For the two-sphere system the formular are evaluated numerically and shown graphically. (G.Q.)
Hot subdwarf binaries from the MUCHFUSS project. Analysis of 12 new systems and a study of the short-period binary population
Kupfer, T.; Geier, S.; Heber, U.; žstensen, R. H.; Barlow, B. N.; Maxted, P. F. L.; Heuser, C.; Schaffenroth, V.; Gõnsicke, B. T.
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (MUCHFUSS) aims at finding hot subdwarf stars with massive compact companions like massive white dwarfs (M > 1.0 M?), neutron stars, or stellar-mass black holes. The existence of such systems is predicted by binary evolution theory, and recent discoveries indicate that they exist in our Galaxy. We present orbital and atmospheric parameters and put constraints on the nature of the companions of 12 close hot subdwarf B star (sdB) binaries found in the course of the MUCHFUSS project. The systems show periods between 0.14 and 7.4 days. In nine cases the nature of the companions cannot be constrained unambiguously whereas three systems most likely have white dwarf companions. We find that the companion to SDSS J083006.17+475150.3 is likely to be a rare example of a low-mass helium-core white dwarf. SDSS J095101.28+034757.0 shows an excess in the infrared that probably originates from a third companion in a wide orbit, which makes this system the second candidate hierarchical triple system containing an sdB star. SDSS J113241.58-063652.8 is the first helium deficient sdO star with a confirmed close companion. This study brings to 142 the number of sdB binaries with orbital periods of less than 30 days and with measured mass functions. We present an analysis of the minimum companion mass distribution and show that it is bimodal. One peak around 0.1 M? corresponds to the low-mass main sequence (dM) and substellar companions. The other peak around 0.4 M? corresponds to the white dwarf companions. The derived masses for the white dwarf companions are significantly lower than the average mass for single carbon-oxygen white dwarfs. In a Teff - log g diagram of sdB+dM companions, we find signs that the sdB components are more massive than the rest of the sample. The full sample was compared to the known population of extremely low-mass white dwarf binaries as well as short-period white dwarfs with main sequence companions. Both samples show a significantly different companion mass distribution indicating either different selection effects or different evolutionary paths. We identified 16 systems where the dM companion will fill its Roche Lobe within a Hubble time and will evolve into a cataclysmic variable; two of them will have a brown dwarf as donor star. Twelve systems with confirmed white dwarf companions will merge within a Hubble time, two of them having a mass ratio to evolve into a stable AM CVn-type binary and another two which are potential supernova Ia progenitor systems. The remaining eight systems will most likely merge and form RCrB stars or massive C/O white dwarfs depending on the structure of the white dwarf companion. Appendix A is available in electronic form at http://www.aanda.org
The HARPS search for southern extra-solar planets. XXXVII. Five new long-period giant planets and a system update
Moutou, C.; Lo Curto, G.; Mayor, M.; Bouchy, F.; Benz, W.; Lovis, C.; Naef, D.; Pepe, F.; Queloz, D.; Santos, N. C.; Sķgransan, D.; Sousa, S. G.; Udry, S.
We describe radial-velocity time series obtained by HARPS on the 3.60 m telescope in La Silla (ESO, Chile) over ten years and report the discovery of five new giant exoplanets in distant orbits; these new planets orbit the stars HD 564, HD 30669, HD 108341, and BD -114672. Their periods range from 492 to 1684 days, semi-major axes range from 1.2 to 2.69 AU, and eccentricities range from 0 to 0.85. Their minimum mass ranges from 0.33 to 3.5 MJup. We also refine the parameters of two planets announced previously around HD 113538, based on a longer series of measurements. The planets have a period of 663 ▒ 8 and 1818 ▒ 25 days, orbital eccentricities of 0.14 ▒ 0.08 and 0.20 ▒ 0.04, and minimum masses of 0.36 ▒ 0.04 and 0.93 ▒ 0.06 MJup. Finally, we report the discovery of a new hot-Jupiter planet around an active star, HD 103720; the planet has a period of 4.5557 ▒ 0.0001 days and a minimum mass of 0.62 ▒ 0.025 MJup. We discuss the fundamental parameters of these systems and limitations due to stellar activity in quiet stars with typical 2 m s-1 radial velocity precision. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope at La Silla (Chile), under the GTO program ID 072.C-0488, 183.C-0972 and the regular programs: 085.C-0019, 087.C-0831, 089.C-0732, 090.C-0421, 091.C-0034, and 092.C-0721.Figures 8 and 9 and Tables 4-9 are available in electronic form at http://www.aanda.org
Thibaut, M.; Ansel, M.; Azevedo Carneiro, J.
Methods of preparing fungal samples for chemical analysis are briefly considered. The basic principles employed in laser microscopy are outlined. The applications of the technique to mycology and to plant biology are discussed. Such a method allows chemical information to be obtained on the same sample and permits the detection of 74 elements in the periodic system of Mendeleev from lithium (3) to uranium (92). The preparative procedures are evaluated according to general histochemical princi...
Periodic Monopoles from Spectral Curves
Maldonado, Rafael
We consider $\\text{SU}(2)$ Bogomolny equations on $\\mathbb{R}^2\\times\\hat{S}^1$ and use the spectral curve defined by the holonomy in the periodic direction to approximate the fields in the limit of large size to period ratio. Symmetries of the Nahm transform allow a study of the effective two dimensional dynamics, which is compared with known results on the full moduli space. The techniques are applied to systems of higher charge and higher rank gauge group, allowing a direct comparison to other periodic Yang-Mills systems.
Reconstrucci¾n de objetos por perfilometrĒa interferomķtrica con sistema de posicionamiento de mira peri¾dica / A reconstruction of objets by interferometric profilometry with positioning system of labeled target periodic
Scientific Electronic Library Online (English)
Nķstor Alonso, Arias-Hernßndez; Martha LucĒa, Molina-Prado; Jaime Enrique, Meneses-Fonseca.
Full Text Available En este trabajo se presenta un mķtodo para extraer informaci¾n 3D usando un microscopio interferomķtrico, sin la necesidad de utilizar un dispositivo transductor piezoelķctrico (PZT, por su siglas en inglķs). En lugar de ello se utiliza un sistema de posicionamiento que aprovecha la sensibilidad a l [...] a fase de una mira peri¾dica, que es registrada mediante el uso de un sistema de visi¾n. El procesamiento de la mira permite calcular la distancia relativa entre el objetivo Mirau y el objeto. Reconstrucciones topogrßficas de algunas dķcimas de milĒmetros fueron calculadas con una precisi¾n de aproximadamente 28 nan¾metros. Se presenta un anßlisis te¾rico y algunos resultados experimentales. Abstract in english A method to extract 3D information using a white light interferometer without using PZT is presented. Instead a positioning system that uses the phase sensitivity of a target periodic is employed. The image treatment realized on the periodic target permits to calculate the relative distance between [...] Mirau objective and object surface. Topographic reconstructions of objects with dimensions of some tenths of millimeters were calculated with an accuracy of approximately 28 nanometers. Theoretical analysis and experimental results are shown.
Effects of linear and nonlinear time-delayed feedback on the noise-enhanced stability phenomenon in a periodically driven bistable system
International Nuclear Information System (INIS)
We investigate numerically the effects of time delay on the phenomenon of noise-enhanced stability (NES) in a periodically modulated bistable system. Three types of time-delayed feedback, including linear delayed feedback, nonlinear delayed feedback and global delayed feedback, are considered. We find a non-monotonic behaviour of the mean first-passage time (MFPT) as a function of the delay time ?, with a maximum in the case of linear delayed feedback and with a minimum in the case of nonlinear delayed feedback. There are two peculiar values of ? around which the NES phenomenon is enhanced or weakened. For the case of global delayed feedback, the increase of ? always weakens the NES phenomenon. Moreover, we also show that the amplitude A and the frequency ? of the periodic forcing play an opposite role in the NES phenomenon, i.e. the increase of A weakens the NES effect while the increase of ? enhances it. These observations demonstrate that the time-delayed feedback can be used as a feasible control scheme for the NES phenomenon
Electron-rich bonding and the importance of s,p mixing as one moves across a period: a lesson from the LiSn system.
Ienco, A; Hoffmann, R; Papoian, G
The electronic structure of an unusual LiSn phase (computed using band structure calculations in the framework of the extended H³ckel tight binding theory) is the starting point for a general analysis of the variation of electron-rich multicenter bonding across a period. The LiSn crystal structure of M³ller and Schõfer in question contains 2D slabs of Sn atoms arranged as microscopic stairs and intercalated by Li atoms. Discrepancies between an electron count derived from a recent extension of the Zintl-Klemm rules to electron-rich systems (5(2/3) electrons) and the experimental one (5 electrons for the Sn sublattice) and other failures of chemical "common sense" emerge in the analysis. The key for interpretation of a series of puzzling results was found in the comparative analysis of the Sn net with other main group element hypervalent slabs. Increasing s,p-mixing as one moves from the right to the left side of the same row of the periodic table is responsible for these effects. The result is that a lower electron count is found in the Sn slabs relative to the one expected from the extended Zintl-Klemm theory. The effect should also occur in discrete molecules. We also showed that the Li atoms have a role in the determination of the final structure, not only because of their small size but also through the degree of the electron transfer to the Sn sublattice. PMID:11456880
ASME N511-19XX, Standard for periodic in-service testing of nuclear air treatment, heating, ventilating and air conditioning systems
Energy Technology Data Exchange (ETDEWEB)
A draft version of the Standard is presented in this document. The Standard covers the requirements for periodic in-service testing of nuclear safety-related air treatment, heating, ventilating, and air conditioning systems in nuclear facilities. The Standard provides a basis for the development of test programs and does not include acceptance criteria, except in cases where the results of one test influence the performance of other tests. The Standard covers general inspection and test requirements, reference values, inspection and test requirements, generic tests, acceptance criteria, in-service test requirements, testing following an abnormal incident, corrective action requirements, and quality assurance. Mandatory appendices provide a visual inspection checklist and four test procedures. Non-mandatory appendices provide additional information and guidance on mounting frame pressure leak test procedure, corrective action, challenge gas substitute selection criteria, and test program development. 8 refs., 10 tabs.