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Sample records for isobaric vapor-liquid equilibrium

  1. Isobaric vapor-liquid equilibrium of the systems cumene + benzyl alcohol and phenol + benzyl alcohol at 10 kPa

    SciTech Connect

    Resa, J.M.; Quintana, T.; Cepeda, E. . Dept. Ingenieria Quimica)

    1994-01-01

    Isobaric vapor-liquid equilibrium data are reported for the binary systems cumene + benzyl alcohol and phenol + benzyl alcohol at 10 kPa. The activity coefficient data were tested for thermodynamic consistency by the methods of Herington, Black, and Van Ness and correlated with the Wilson equation. None of the systems show an azeotrope.

  2. A "User-Friendly" Program for Vapor-Liquid Equilibrium.

    ERIC Educational Resources Information Center

    Da Silva, Francisco A.; And Others

    1991-01-01

    Described is a computer software package suitable for teaching and research in the area of multicomponent vapor-liquid equilibrium. This program, which has a complete database, can accomplish phase-equilibrium calculations using various models and graph the results. (KR)

  3. Isobaric vapor-liquid equilibria in the system methyl propanoate + n-butyl alcohol

    SciTech Connect

    Susial, P.; Ortega, J. . Lab. de Termodinamica y Fisicoquimica)

    1993-10-01

    Isobaric vapor-liquid equilibria were determined at 74.66, 101.32, and 127.99 kPa for binary mixtures containing methyl propanoate + n-butyl alcohol by using a dynamic still with vapor and liquid circulation. No azeotrope was detected. The data were found to be thermodynamically consistent according to the point to point test. Application of the group-contribution models ASOG, UNIFAC, and modified UNIFAC to the activity coefficients at the three pressures studied gives average errors of less than 10%, 11%, and 3%, respectively.

  4. VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE FROM

    E-print Network

    VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE the vapor-liquid equilibrium of water (between 323 and 573 K), carbon dioxide (between 230 and 290 K) and their binary mixtures (between 348 and 393 K). The properties of supercritical carbon dioxide were determined

  5. Vapor-liquid equilibrium in electric field gradients.

    PubMed

    Samin, Sela; Tsori, Yoav

    2011-01-13

    We investigate the vapor-liquid coexistence of polar and nonpolar fluids in the presence of a nonuniform electric field. We find that a large enough electric field can nucleate a gas bubble from the liquid phase or a liquid droplet from the vapor phase. The surface tension of the vapor-liquid interface is determined within squared-gradient theory. When the surface potential (charge) is controlled, the surface tension increases (decreases) compared to the zero-field interface. The effect of the electric field on the fluid phase diagram depends strongly on the constitutive relation for the dielectric constant. Finally, we show that gas bubbles can be nucleated far from the bounding surfaces. PMID:21142049

  6. Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at 35 70 C

    E-print Network

    Rochelle, Gary T.

    Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at 35 ­ 70 ºC Topical Report Prepared of Texas at Austin May 2006 #12;Dedication To my parents, John and Susan McLees. You believed in my every about my experimental methods from running the FTIR system to data analysis, and even the kinds

  7. Vapor-liquid equilibrium measurements for methyl propanoate-ethanol and methyl propanoate-propan-1-ol at 101. 32 kPa

    SciTech Connect

    Susial, P.; Ortega, J. ); DeAlfonso, C.; Alonso, C. )

    1989-04-01

    Isobaric vapor-liquid equilibrium measurements on binary systems of methyl propanoate with ethanol and propan-1-ol are taken at a constant pressure of 101.32 +- 0.02 kPa. These systems exhibit significant deviations from ideality and are shown to be thermodynamically consistent. The methyl propanoate-ethanol system forms an azeotrope at x = y = 0.483 and T = 345.58{Kappa}. Experimental data are fitted to a suitable equation and are likewise compared with the values predicted by the UNIFAC and ASOG models.

  8. Condensation coefficient of methanol vapor near vapor-liquid equilibrium states

    NASA Astrophysics Data System (ADS)

    Fujikawa, S.; Yano, T.; Ichijo, M.; Iwanami, K.

    This paper is concerned with the nonequilibrium condensation from a vapor to a liquid phase on the plate endwall of a shock tube behind a reflected shock wave. The growth of a liquid film on the endwall is measured by an optical interferometer using a laser beam. The experiment is carefully conducted on the precisely designed apparatus, and thereby the condensation coefficient of methanol vapor is determined in a wide range of vapor-liquid conditions from near to far from equilibrium states. The result shows that the condensation coefficient increases with the increase of the ratio of number densities of vapor and saturated vapor at the interface.

  9. A new vapor-liquid equilibrium apparatus for hydrogen fluoride containing systems

    SciTech Connect

    Jongcheon Lee; Hwayong Kim; Jong Sung Lim; Jae-Duck Kim; Youn Yong Lee

    1996-12-31

    A new circulating type apparatus has been constructed to obtain reliable equilibrium PTxy data for hydrogen fluoride (HF) containing system. Equilibrium cell with Pyrex windows protected by Teflon PFA sheets to prevent the corrosion was used. Isothermal vapor-liquid equilibrium data for the 1,1-difluoroethane (HFC-152a) + HF system at 288.23 and 298.35 K were obtained, and compared with PTx measurement results. Experimental data were correlated using Lencka and Anderko equation of state for HF with the Wong-Sandler mixing rule as well as the van der Waals one fluid mixing rule. The Wong-Sandler mixing rule gives better results. 5 refs., 3 figs.

  10. Vapor-Liquid Equilibrium Measurements of the Binary R32+R125 Refrigerant Mixture

    NASA Astrophysics Data System (ADS)

    Higashi, Yukihiro; Miyake, Takeshi; Fujii, Ken-Ichi

    Vapor-liquid equilibrium (VLE) data of the binary R32+R125 refrigerant mixture including R410A (50mass% R32 + 50mass% R125) were obtained by the circulation-type experimental apparatus with a liquid-bath thermostat. VLE measurements were carried out in the temperatures between 263.15 K and 318.15 K and in the pressures between 505 kPa and 2724 kPa. The experimental uncertainties of temperature, pressure, and composition measurements were estimated to be within 3 mK, 0.1 %, and 0.4 %, respectively. The present data were compared with reported experimental data against the REFPROP 6.01 as well as REFPROP 7.0 calculation results.

  11. Solvent-refined coal (SRC) process. Vapor-liquid equilibrium measurements for the SRC-II process

    SciTech Connect

    Henry, R. M.

    1980-10-01

    This report summarizes vapor-liquid equilibrium studies conducted to support the Solvent Refined Coal project by the Pittsburg and Midway Coal Mining Company under contract with the Department of Energy. Discussed herein are experimental details and results of measurements to obtain vapor-liquid equilibrium data at conditions simulating those which occur during the gas-liquid separation steps in the SRC-II coal liquefaction process. Separation and compositional analyses of liquid and gas phases permitted calculation of the equilibrium K values for the various components of the mixture. Experimental methods and apparatus used in this work were compared to a system recently described in the literature. The measured K values agreed to within an average of +- 5% of published values and showed that the experimental system developed is satisfactory. Internal consistency of each experiment was evaluated by a material balance consistency test, and an average material balance of 99.7% was obtained over the 15 experiments. Data obtained from this work will serve as the basis for K value correlations used in process design calculations for the SRC-II Demonstration Plant.

  12. Vapor-liquid equilibrium of hexadecapolar fluids from a perturbation-based equation of state.

    PubMed

    Gámez, Francisco; Lago, Santiago; del Río, Fernando; Benavides, Ana Laura

    2006-09-14

    In this work a numerically tractable expression for the interaction potential between two point hexadecapoles with octahedral symmetry and a molecular-based equation of state derived by perturbation theory for hexadecapolar fluids are presented. The polar system is modeled by square-well particles with a point hexadecapole with octahedral symmetry at their centers. This equation of state is analytical in the state variables and in the potential parameters and allows us to study the effects of the hexadecapolar moment strength on the thermodynamic properties and liquid-vapor phase diagram. The equation presented here is applied to the thermodynamics of sulfur hexafluoride and gives very good predictions for the saturation pressures and the vapor-liquid phase diagram. PMID:16999539

  13. On the vapor-liquid equilibrium of attractive chain fluids with variable degree of molecular flexibility.

    PubMed

    van Westen, Thijs; Vlugt, Thijs J H; Gross, Joachim

    2015-06-14

    We study the isotropic (vapor and liquid) phase behavior of attractive chain fluids. Special emphasis is placed on the role of molecular flexibility, which is studied by means of a rod-coil model. Two new equations of state (EoSs) are developed for square-well- (SW) and Lennard-Jones (LJ) chain fluids. The EoSs are developed by applying the perturbation theory of Barker and Henderson (BH) to a reference fluid of hard chain molecules. The novelty of the approach is based on (1) the use of a recently developed hard-chain reference EoS that explicitly incorporates the effects of molecular flexibility, (2) the use of recent molecular simulation data for the radial distribution function of hard-chain fluids, and (3) a newly developed effective segment size, which effectively accounts for the soft repulsion between segments of LJ chains. It is shown that the effective segment size needs to be temperature-, density-, and chain-length dependent. To obtain a simplified analytical EoS, the perturbation terms are fitted by polynomials in density (SW and LJ), chain length (SW and LJ), and temperature (only for LJ). It is shown that the equations of state result in an accurate description of molecular simulation data for vapor-liquid equilibria (VLE) and isotherms of fully flexible SW- and LJ chain fluids and their mixtures. To evaluate the performance of the equations of state in describing the effects of molecular flexibility on VLE, we present new Monte Carlo simulation results for the VLE of rigid linear- and partially flexible SW- and LJ chain fluids. For SW chains, the developed EoS is in a good agreement with simulation results. For increased rigidity of the chains, both theory and simulations predict an increase of the VL density difference and a slight increase of the VL critical temperature. For LJ chains, the EoS proves incapable of reproducing part of these trends. PMID:26071717

  14. Determination of vapor-liquid equilibrium data and decontamination factors needed for the development of evaporator technology for use in volume reduction of radioactive waste streams

    SciTech Connect

    Betts, S.E.

    1993-10-01

    A program is currently in progress at Argonne National Laboratory to evaluate and develop evaporator technology for concentrating radioactive waste streams. By concentrating radioactive waste streams, disposal costs can be significantly reduced. To effectively reduce the volume of waste, the evaporator must achieve high decontamination factors so that the distillate is sufficiently free of radioactive material. One technology that shows a great deal of potential for this application is being developed by LICON, Inc. In this program, Argonne plans to apply LICON`s evaporator designs to the processing of radioactive solutions. Concepts that need to be incorporated into the design of the evaporator include, criticality safety, remote operation and maintenance, and materials of construction. To design an effective process for concentrating waste streams, both solubility and vapor-liquid equilibrium data are needed. The key issue, however, is the high decontamination factors that have been demonstrated by this equipment. Two major contributions were made to this project. First, a literature survey was completed to obtain available solubility and vapor-liquid equilibrium data. Some vapor-liquid data necessary for the project but not available in the literature was obtained experimentally. Second, the decontamination factor for the evaporator was determined using neutron activation analysis (NAA).

  15. Isothermal vapor--liquid equilibrium data for binary systems at high pressures; Carbon dioxide-methanol, carbon dioxide-ethanol, carbon dioxide--1-propanol, methane--ethanol, methane--1-propanol, ethane--ethanol, and ethane--1-propanol systems

    SciTech Connect

    Suzuki, K.; Sue, H. ); Itou, M.; Smith, R.L.; Inomata, H.; Aria, K.; Saito, S. )

    1990-01-01

    This paper reports an experiment conducted on isothermal vapor-liquid equilibrium data for binary systems at high pressure. Carbon dioxide-methanol, carbon dioxide-ethanol, carbon dioxide-1-propanol, methane-ethanol, methane-1-propanol, ethane-ethanol, and ethane-1-propanol were measured by a new static phase equilibrium apparatus at 313.4 and 333,4 K.

  16. Vapor-Liquid Equilibrium in the Mixture 1-Chloropropane C3H7Cl + C4H8O2 1,4-Dioxane (EVLM1231, LB5713_E)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1-Chloropropane C3H7Cl + C4H8O2 1,4-Dioxane (EVLM1231, LB5713_E)' providing data from direct measurement of temperature and mole fraction in vapor phase at variable mole fraction in liquid phase and constant pressure.

  17. Determination of vapor-liquid equilibrium data in microfluidic segmented flows at elevated pressures using Raman spectroscopy.

    PubMed

    Luther, Sebastian K; Stehle, Simon; Weihs, Kristian; Will, Stefan; Braeuer, Andreas

    2015-08-18

    A fast, noninvasive, and efficient analytical measurement strategy for the characterization of vapor-liquid equilibria (VLE) is presented, which is based on phase (state of matter) selective Raman spectroscopy in multiphase flows inside microcapillay systems (MCS). Isothermal VLE data were measured in binary and ternary mixtures composed of acetone, water, carbon dioxide or nitrogen at elevated pressures up to 10 MPa and temperatures up to 333 K. For validation, the obtained data were compared with literature data and reference measurements in a high-pressure variable volume cell. Additionally, the mixtures were investigated at temperatures and pressures where no data is available in literature to extend the high-pressure VLE database. PMID:26171990

  18. Isobaric Molecular Dynamics Version of the Generalized Replica Exchange Method (gREM): Liquid-Vapor Equilibrium.

    PubMed

    Ma?olepsza, Edyta; Secor, Maxim; Keyes, Tom

    2015-10-22

    A prescription for sampling isobaric generalized ensembles with molecular dynamics is presented and applied to the generalized replica exchange method (gREM), which was designed to simulate first-order phase transitions. The properties of the isobaric gREM ensemble are discussed, and a study is presented for the liquid-vapor equilibrium of the guest molecules given for gas hydrate formation with the mW water model. Phase diagrams, critical parameters, and a law of corresponding states are obtained. PMID:26398582

  19. Representing Vapor-Liquid Equilibrium for an Aqueous MEA-CO2 System Using the Electrolyte Nonrandom-Two-Liquid Model

    E-print Network

    Zhang, Luzheng

    equilibrium constants, Henry's constant, experimental data, and data regression on the representation to experimental data. A good agreement between the calculated values and the experimental data was achieved are defined in the liquid phase. The equilibrium constants of the amine dissociation reaction and car- bamate

  20. Vapor-Liquid Equilibria Using the Gibbs Energy and the Common Tangent Plane Criterion

    ERIC Educational Resources Information Center

    Olaya, Maria del Mar; Reyes-Labarta, Juan A.; Serrano, Maria Dolores; Marcilla, Antonio

    2010-01-01

    Phase thermodynamics is often perceived as a difficult subject with which many students never become fully comfortable. The Gibbsian geometrical framework can help students to gain a better understanding of phase equilibria. An exercise to interpret the vapor-liquid equilibrium of a binary azeotropic mixture, using the equilibrium condition based…

  1. Calculation of vapor-liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part III. Extension to water-light hydrocarbons systems

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Lai, Shaocong; Dubessy, Jean

    2014-01-01

    The SAFT-LJ EOS improved by Sun and Dubessy (2010, 2012) is extended to water-light hydrocarbon systems. Light hydrocarbons (including CH4, C2H6, C3H8 and nC4H10) are modeled as chain molecules without multi-polar moments. The contributions of the shape of molecules and main intermolecular interactions existing in water-light hydrocarbon systems (including repulsive and attractive forces between Lennard-Jones segments, the hydrogen-bonding force and the multi-polar interaction between water molecules) to the residual Helmholtz energy were accounted for by this EOS. The adjustable parameters for the interactions of H2O-CH4, H2O-C2H6, H2O-C3H8, and H2O-nC4H10 pairs were evaluated from mutual solubility data of binary water-hydrocarbon systems at vapor-liquid equilibria. Comparison with the experimental data shows this SAFT-LJ EOS can represent well vapor-liquid (and liquid-liquid) equilibria of binary water-light hydrocarbon systems over a wide P-T range. The accuracy of this EOS for mutual solubilities of methane, ethane, propane and water is within the experimental uncertainty generally. Moreover, the model is able to accurately predict the vapor-liquid equilibria and PVTx properties of multi-component systems composed of water, light hydrocarbon as well as CO2. As we know, this EOS is the first one allowing quantitative calculation of the mutual solubilities of water and light hydrocarbons over a wide P-T range among SAFT-type EOSs. This work indicates that the molecular-based EOS combined with conventional mixing rule can well describe the thermodynamic behavior of highly non-ideal systems such as water-light hydrocarbons mixtures except in the critical region for which long range density fluctuations cannot be taken into account by this analytical model.

  2. Boundary conditions on the vapor liquid interface at strong condensation

    NASA Astrophysics Data System (ADS)

    Kryukov, A. P.; Levashov, V. Yu.

    2015-08-01

    The problem of the formulation of boundary conditions on the vapor-liquid interface is considered. The different approaches to this problem and their difficulties are discussed. Usually, a quasi-equilibrium scheme is used. At sufficiently large deviations from thermodynamic equilibrium, a molecular kinetics approach should be used for the description of the vapor flow at condensation. The formulation of the boundary conditions at the vapor liquid interface to solve the Boltzmann kinetic equation for the distribution of molecules by velocity is a sophisticated problem. It appears that molecular dynamics simulation (MDS) can be used to provide this solution at the interface. The specific problems occur in the realization of MDS on large time and space scales. Some of these problems, and a hierarchy of continuum, kinetic and molecular dynamic time scales, are discussed in the paper. A description of strong condensation at the kinetic level is presented for the steady one-dimensional problem. A formula is provided for the calculation of the limiting condensation coefficient. It is shown that as the condensation coefficient approaches the limiting value, the vapor pressure rises significantly. The results of the corresponding calculations for the Mach number and temperature at different vapor flows are demonstrated. As a result of the application of the molecular kinetics method and molecular dynamics simulation to the problem of the determination of argon condensation coefficients in the range of temperatures of vapor and liquid ratio 1.0-4.0, it is concluded that the condensation coefficient is close to unity.

  3. Vapor-liquid phase separator studies

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.; Hepler, W. A.; Frederking, T. H. K.

    1985-01-01

    A study of porous plug use for vapor-liquid phase seperation in spaceborne cryogenic systems was conducted. The three main topics addressed were: (1) the usefulness of porous media in designs that call for variable areas and flow rates; (2) the possibility of prediction of main parameters of porous plugs for a given material; and (3) prediction of all parameters of the plug, including secondary parameters.

  4. Vapor-liquid equilibria in the systems toluene/naphthalene and cyclohexane/naphthalene

    SciTech Connect

    Lee, Changha; Holder, G.D. )

    1993-04-01

    In this study, the authors report isothermal vapor-liquid equilibrium (VLE) data for the toluene/naphthalene and cyclohexane/naphthalene systems which can be considered as model compounds for coal liquids. Vapor-liquid equilibrium data for the binary systems toluene/naphthalene and cyclohexane/naphthalene were measured at 0-1,300 kPa and 370-500 K using a 1-L stirred autoclave system. All pure components and binary P-T data were well fitted with a three-constant Antoine equation. The data can bee accurately correlated with the modified Peng-Robinson equation of state using density-dependent mixing rules to describe both the vapor and liquid phases. The binary interaction parameters and correction factors for the equation of state are reported at each isotherm.

  5. Vapor-Liquid Equilibria for Some Concentrated Aqueous PolymerSolutions

    SciTech Connect

    Striolo, Alberto; Prausnitz, John M.

    1999-07-01

    Vapor-liquid-equilibrium data were obtained for binary aqueous solutions of six water-soluble linear polymers in the range 70-95 C. A classical gravimetric sorption method was used to measure the amount of solvent absorbed as a function of vapor-phase water pressure. Polymers studied were polyvinylpyrrolidone, polyethyleneoxide, polyvinylalcohol, hydroxyethylcellulose, polyethylenimine, polymethylvinylether. The experimental data were reduced with Hino's lattice model that distinguished the interactions due to London dispersion forces and those due to hydrogen bonding.

  6. Liquid-liquid and vapor-liquid phase equilibria for 1-butanol + water + 2-propanol at ambient pressure

    SciTech Connect

    Aicher, T.; Bamberger, T.; Schluender, E.U.

    1995-05-01

    The liquid-liquid and the vapor-liquid phase equilibria of the ternary system 1-butanol + water + 2-propanol have been measured at ambient pressure. Compositions along the binodal curve have been determined gravimetrically at 0, 20, 50, and 60 C. The lines were determined for 0, 20, and 60 C. The data were compared to reported measurements at 80 C. Furthermore, the vapor-liquid equilibrium at ambient pressure has been measured for both one-phase and two-phase liquid mixtures using a recirculation still proposed by Roeck and Sieg.

  7. Vapor-liquid equilibria of sulfur dioxide in polar organic solvents

    SciTech Connect

    Demyanovich, R.J.; Lynn, S.

    1987-03-01

    Vapor-liquid equilibrium data for SO/sub 2/ in eight polar organic solvents and three mixtures of organic solvents were investigated over the temperature range 30-95/sup 0/C and over a concentration range of 0.02-0.16 weight fraction of SO/sub 2/. The solvents investigated were N, N-dimethylaniline (DMA); quinoline; the dimethyl ethers of diethylene glycol, triethylene glycol, and tetraethylene glycol; the monomethyl ether of diethylene glycol (DGM); tetramethylene sulfone; and tributyl phosphate. The mixed solvents investigated were various mixtures of DMA and DGM. The data were correlated by using the UNIQUAC, NRTL, Wilson, and Henry's law phase-equilibrium models.

  8. Phase diagram of nanoscale alloy particles used for vapor-liquid-solid growth of semiconductor nanowires.

    PubMed

    Sutter, Eli; Sutter, Peter

    2008-02-01

    We use transmission electron microscopy observations to establish the parts of the phase diagram of nanometer sized Au-Ge alloy drops at the tips of Ge nanowires (NWs) that determine their temperature-dependent equilibrium composition and, hence, their exchange of semiconductor material with the NWs. We find that the phase diagram of the nanoscale drop deviates significantly from that of the bulk alloy, which explains discrepancies between actual growth results and predictions on the basis of the bulk-phase equilibria. Our findings provide the basis for tailoring vapor-liquid-solid growth to achieve complex one-dimensional materials geometries. PMID:18193910

  9. The effect of sulfur on vapor liquid fractionation of metals in hydrothermal systems

    NASA Astrophysics Data System (ADS)

    Pokrovski, Gleb S.; Borisova, Anastassia Yu.; Harrichoury, Jean-Claude

    2008-02-01

    Despite the growing evidence that the vapor phase, formed through magma degassing and ore fluid boiling, can selectively concentrate and transport metals, the effects of major volatile components like sulfur, chlorine or carbon dioxide on the metal vapor-liquid fractionation and vapor-phase transport under magmatic-hydrothermal conditions remain poorly known. We performed systematic experiments to investigate the effect of sulfur ligands on metal vapor-liquid partitioning in model H 2O-S-NaCl-KCl-NaOH systems at temperatures from 350 to 500 °C. Results show that at acidic-to-neutral conditions, vapor-liquid equilibrium distribution coefficients, Km = mvapor / mliquid, where m is the mass concentration of the metal in corresponding phase, of metalloids (As, Sb) and base metals (Zn, Fe, Pb, Ag) are in the range 0.1-1.0 and 0.001-0.1, respectively, and are not significantly affected by the presence of geologically common sulfur concentrations, up to 1-3 wt.% S. In contrast, the partitioning of Cu, Au, and Pt into the vapor increases by a factor of 100 in comparison to the S-free water-salt system, yielding Km values of 0.5-1.0, 1-10, and 10-20, respectively, due to formation of volatile neutral complexes with H 2S and, possibly, SO 2. In neutral-to-basic systems, Zn, Pb, Fe and Ag show 10-100-fold increase of their partition coefficients, whereas Cu, Au and Pt exhibit Km values of up to several orders of magnitude lower, compared to acidic conditions at similar temperature, pressure and sulfur contents. These vapor-liquid distribution patterns result from combined effects of i) formation of volatile species with reduced sulfur ligands in the vapor phase, ii) changes in the metal speciation in the coexisting liquid phase as a function of pH, and iii) solute-solvent interactions in both phases. Our data explain the vapor-liquid fractionation trends for many metals as inferred in coexisting brine and vapor inclusions from magmatic-hydrothermal deposits, and provide a first experimental evidence for the dramatic increase of the mobility of Cu, Au and Pt in sulfur-enriched acidic magmatic-hydrothermal vapors, consistent with geological models of Au ± Cu ores formation and distribution in porphyry-epithermal settings.

  10. Nanoporous quantum filters: inside vapor-liquid transitions of quantum fluids in nanopores.

    PubMed

    Kowalczyk, Piotr; Gauden, Piotr A; Terzyk, Artur P

    2010-04-22

    We study the impact of quantum fluctuations on the phase diagram of a realistic quantum liquid, namely, neon confined in atomistic carbon nanopores at 35 K. Due to the action of attractive solid-fluid potential, both classical and quantum neon vapor condense at lower pressures in carbonaceous nanopores than bulk neon. However, we found that continuous van der Waals s-shaped isotherms, which include stable, metastable, and unstable states computed from classical simulations, are shifted to lower values of pressures in comparison to those from path integral calculations. This systematic underestimation of equilibrium vapor-liquid transition pressures as well as spinodals in classical simulations is caused by neglecting the zero-point motion of adsorbed neon at 35 K. Delocalized neon atoms excluded more volume in the adsorbed phase than the classical neon particles. Thus, adsorbed and compressed liquidlike phases of quantum neon in the studied nanopores are characterized by lower densities than their classical counterparts. Interestingly, equilibrium vapor-liquid transition pressures of confined neon at 35 K computed from classical simulations are shifted to lower values in comparison to those computed from quantum simulations by approximately 30% for different pore sizes. Simulations of classical neon at higher effective temperatures reveal that liquidlike phases of confined quantum neon at 35 K look like classical ones at higher effective temperature of 37 K. Our calculations clearly show that quantum fluctuations cannot be neglected in calculations of phase transitions of quantum fluids at cryogenic temperatures. PMID:20345103

  11. Vapor-liquid coexistence of patchy models: Relevance to protein phase behavior

    E-print Network

    Sciortino, Francesco

    Vapor-liquid coexistence of patchy models: Relevance to protein phase behavior Hongjun Liu online 22 August 2007 The vapor-liquid coexistence boundaries of fluids composed of particles interacting, it is established that the reduced widths of the metastable vapor-liquid coexistence curve predicted by a model

  12. Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica exchange method

    NASA Astrophysics Data System (ADS)

    Lu, Qing; Kim, Jaegil; Straub, John E.

    2013-03-01

    The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by "backbending" in the statistical temperature. While the metastable and unstable states in the vicinity of the first-order phase transition are masked by the enthalpy gap in temperature replica exchange method simulations, they are transformed into stable states through the parameterized effective sampling weights in gREM simulations, and join vapor and liquid phases with a succession of unimodal enthalpy distributions. The enhanced sampling across metastable and unstable states is achieved without the need to identify a "good" order parameter for biased sampling. We performed gREM simulations at various pressures below and near the critical pressure to examine the change in behavior of the vapor-liquid phase transition at different pressures. We observed a crossover from the first-order phase transition at low pressure, characterized by the backbending in the statistical temperature and the "kink" in the Gibbs free energy, to a continuous second-order phase transition near the critical pressure. The controlling mechanisms of nucleation and continuous phase transition are evident and the coexistence properties and phase diagram are found in agreement with literature results.

  13. Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica exchange method.

    PubMed

    Lu, Qing; Kim, Jaegil; Straub, John E

    2013-03-14

    The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by "backbending" in the statistical temperature. While the metastable and unstable states in the vicinity of the first-order phase transition are masked by the enthalpy gap in temperature replica exchange method simulations, they are transformed into stable states through the parameterized effective sampling weights in gREM simulations, and join vapor and liquid phases with a succession of unimodal enthalpy distributions. The enhanced sampling across metastable and unstable states is achieved without the need to identify a "good" order parameter for biased sampling. We performed gREM simulations at various pressures below and near the critical pressure to examine the change in behavior of the vapor-liquid phase transition at different pressures. We observed a crossover from the first-order phase transition at low pressure, characterized by the backbending in the statistical temperature and the "kink" in the Gibbs free energy, to a continuous second-order phase transition near the critical pressure. The controlling mechanisms of nucleation and continuous phase transition are evident and the coexistence properties and phase diagram are found in agreement with literature results. PMID:23514477

  14. Molecular simulation of the vapor-liquid coexistence of mercury

    NASA Astrophysics Data System (ADS)

    Raabe, Gabriele; Sadus, Richard J.

    2003-10-01

    The vapor-liquid coexistence properties of mercury are determined from molecular simulation using empirical intermolecular potentials, ab initio two-body potentials, and an effective multibody intermolecular potential. Comparison with experiment shows that pair-interactions alone are inadequate to account for the vapor-liquid coexistence properties of mercury. It is shown that very good agreement between theory and experiment can be obtained by combining an accurate two-body ab initio potential with the addition of an empirically determined multibody contribution. As a consequence of this multibody contribution, we can reliably predict mercury's phase coexistence properties and the heats of vaporization. The pair distribution function of mercury can also be predicted with reasonable accuracy.

  15. Silicon nanowire synthesis by a vapor-liquid-solid approach

    NASA Technical Reports Server (NTRS)

    Mao, Aaron; Ng, H. T.; Nguyen, Pho; McNeil, Melanie; Meyyappan, M.

    2005-01-01

    Synthesis of silicon nanowires is studied by using a vapor-liquid-solid growth technique. Silicon tetrachloride reduction with hydrogen in the gas phase is used with gold serving as catalyst to facilitate growth. Only a narrow set of conditions of SiCl4 concentration and temperature yield straight nanowires. High concentrations and temperatures generally result in particulates, catalyst coverage and deactivation, and coatinglike materials.

  16. Integrated vapor-liquid-solid silicon mass sensors (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Bryce, Brian A.; Gorman, Jason J.; Keylyuk, Sergiy; Davydov, Albert

    2015-08-01

    We present the results and progress of research to create a multiplex chemical sensor based on Au catalyzed vapor-liquid-solid (VLS) silicon nanowires deployed as resonant mass sensors. Each element of this sensor has a single VLS wire grown in close proximity to a Si photodiode. Together they create a Fabry-Pérot interferometer that allows for the sensitive detection of the beam's resonant motion. Small changes in mass on the cantilever that occur as a result of chemical absorption on the functionalized Au surface shift the resonant frequency. Our integrated approach will allow large reductions in system complexity for this sensor class.

  17. A study of vapor-liquid flow in porous media

    SciTech Connect

    Satik, Cengiz; Yortsos, Yanis C.

    1994-01-20

    We study the heat transfer-driven liquid-to-vapor phase change in single-component systems in porous media by using pore network models and flow visualization experiments. Experiments using glass micromodels were conducted. The flow visualization allowed us to define the rules for the numerical pore network model. A numerical pore network model is developed for vapor-liquid displacement where fluid flow, heat transfer and capillarity are included at the pore level. We examine the growth process at two different boundary conditions.

  18. Vapors-liquid phase separator. [infrared telescope heat sink

    NASA Technical Reports Server (NTRS)

    Frederking, T. H. K.; Brown, G. S.; Chuang, C.; Kamioka, Y.; Kim, Y. I.; Lee, J. M.; Yuan, S. W. K.

    1980-01-01

    The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase separators for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area variation was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.

  19. Size-dependent phase diagram of nanoscale alloy drops used in vapor--liquid--solid growth of semiconductor nanowires.

    PubMed

    Sutter, Eli A; Sutter, Peter W

    2010-08-24

    We use in situ observations during high-temperature transmission electron microscopy to quantify the exchange of semiconductor material between Au-Ge vapor--liquid--solid seed drops and Ge nanowires (NWs). By performing simultaneous measurements under identical conditions on arrays with systematic variations in NW diameter, we establish the nanoscale size dependence of the temperature-dependent equilibrium composition of the Au-Ge binary alloy. We find a significantly enhanced Ge solubility for drops on thin NWs compared to thicker ones. The controlled modification of the surface of the NW by an ordered carbon shell leads to drastic changes in the solubility. PMID:20731466

  20. A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties

    E-print Network

    A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties Jeffrey R@ipst.umd.edu #12;1 Abstract A new fixed-point charge potential model for water has been developed, targeting the accurate prediction of the vapor-liquid coexistence properties over a broad temperature range. The model

  1. New Exciplex Fluorescence System for Vapor-Liquid Visualization

    NASA Astrophysics Data System (ADS)

    Kim, J. U.; Darrow, Jon; Nocera, D. G.; Schock, H. J.; Golding, B.

    1997-03-01

    We report a new and viable diagnostic chemical systems for two phase vapor-liquid visualization based on exciplex (excited state complex) formed between N,N-dimethylaniline (DMA) and 1,4,6- trimethylnaphthalene (1,4,6-TMN) in isooctane.( J. U. Kim et al., ``Exciplex Fluorescence Visualization Systems for Pre-Combustion Diagnosis of an Automotive Gasoline Engine'', SAE paper 960826, 1996 ) Steady-state and time-resolved emission spectroscopies were used in order to study the exciplex kinetics. Temperature dependent measurements of the exciplex fluorescence reveal that the quenching mechanism associated with the exciplex is sufficiently favorable to permit the exciplex to exist at temperatures approaching 150^circ C. This system is designed to probe the spatial and temporal evolution of fuel mixture formation in a spark ignition engine by use of spectrally well-separated fluorescence images obtained from the monomer and exciplex constituents dissolved in gasoline fuel.

  2. Surface tension and vapor-liquid phase coexistence of confined square-Jayant K. Singh and Sang Kyu Kwak

    E-print Network

    Singh, Jayant K.

    Surface tension and vapor-liquid phase coexistence of confined square- well fluid Jayant K. Singh://jcp.aip.org/about/rights_and_permissions #12;Surface tension and vapor-liquid phase coexistence of confined square-well fluid Jayant K. Singha is in agreement with that given in literature. The surface tension of the vapor-liquid interface is calculated via

  3. Extended vapor-liquid-solid growth of silicon carbide nanowires.

    PubMed

    Rajesh, John Anthuvan; Pandurangan, Arumugam

    2014-04-01

    We developed an alloy catalytic method to explain extended vapor-liquid-solid (VLS) growth of silicon carbide nanowires (SiC NWs) by a simple thermal evaporation of silicon and activated carbon mixture using lanthanum nickel (LaNi5) alloy as catalyst in a chemical vapor deposition process. The LaNi5 alloy binary phase diagram and the phase relationships in the La-Ni-Si ternary system were play a key role to determine the growth parameters in this VLS mechanism. Different reaction temperatures (1300, 1350 and 1400 degrees C) were applied to prove the established growth process by experimentally. Scanning electron microscopy and transmission electron microscopy studies show that the crystalline quality of the SiC NWs increases with the temperature at which they have been synthesized. La-Ni alloyed catalyst particles observed on the top of the SiC NWs confirms that the growth process follows this extended VLS mechanism. The X-ray diffraction and confocal Raman spectroscopy analyses demonstrate that the crystalline structure of the SiC NWs was zinc blende 3C-SiC. Optical property of the SiC NWs was investigated by photoluminescence technique at room temperature. Such a new alloy catalytic method may be extended to synthesis other one-dimensional nanostructures. PMID:24734687

  4. Effect of dimensionality on vapor-liquid phase transition

    SciTech Connect

    Singh, Sudhir Kumar

    2014-04-24

    Dimensionality play significant role on ‘phase transitions’. Fluids in macroscopic confinement (bulk or 3-Dimensional, 3D) do not show significant changes in their phase transition properties with extent of confinement, since the number of molecules away from the surrounding surfaces is astronomically higher than the number of molecules in close proximity of the confining surfaces. In microscopic confinement (quasi 3D to quasi-2D), however, the number of molecules away from the close proximity of the surface is not as high as is the case with macroscopic (3D) confinement. Hence, under the same thermodynamic conditions ‘phase transition’ properties at microscopic confinement may not remain the same as the macroscopic or 3D values. Phase transitions at extremely small scale become very sensitive to the dimensions as well as the surface characteristics of the system. In this work our investigations reveal the effect of dimensionality on the phase transition from 3D to quasi-2D to 2D behavior. We have used grand canonical transition matrix Monte Carlo simulation to understand the vapor–liquid phase transitions from 3D to quasi-2D behavior. Such studies can be helpful in understanding and controlling the fluid film behaviour confined between solid surfaces of few molecular diameters, for example, in lubrication applications.

  5. Magnetotail dynamics under isobaric constraints

    NASA Technical Reports Server (NTRS)

    Birn, Joachim; Schindler, Karl; Janicke, Lutz; Hesse, Michael

    1994-01-01

    Using linear theory and nonlinear MHD simulations, we investigate the resistive and ideal MHD stability of two-dimensional plasma configurations under the isobaric constraint dP/dt = 0, which in ideal MHD is equivalent to conserving the pressure function P = P(A), where A denotes the magnetic flux. This constraint is satisfied for incompressible modes, such as Alfven waves, and for systems undergoing energy losses. The linear stability analysis leads to a Schroedinger equation, which can be investigated by standard quantum mechanics procedures. We present an application to a typical stretched magnetotail configuration. For a one-dimensional sheet equilibrium characteristic properties of tearing instability are rediscovered. However, the maximum growth rate scales with the 1/7 power of the resistivity, which implies much faster growth than for the standard tearing mode (assuming that the resistivity is small). The same basic eigen-mode is found also for weakly two-dimensional equilibria, even in the ideal MHD limit. In this case the growth rate scales with the 1/4 power of the normal magnetic field. The results of the linear stability analysis are confirmed qualitatively by nonlinear dynamic MHD simulations. These results suggest the interesting possibility that substorm onset, or the thinning in the late growth phase, is caused by the release of a thermodynamic constraint without the (immediate) necessity of releasing the ideal MHD constraint. In the nonlinear regime the resistive and ideal developments differ in that the ideal mode does not lead to neutral line formation without the further release of the ideal MHD constraint; instead a thin current sheet forms. The isobaric constraint is critically discussed. Under perhaps more realistic adiabatic conditions the ideal mode appears to be stable but could be driven by external perturbations and thus generate the thin current sheet in the late growth phase, before a nonideal instability sets in.

  6. Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase

    USGS Publications Warehouse

    Moench, A.F.; Atkinson, P.G.

    1978-01-01

    A finite-difference model for the radial horizontal flow of steam through a porous medium is used to evaluate transient-pressure behavior in the presence of an immobile vaporizing or condensing liquid phase. Graphs of pressure drawdown and buildup in terms of dimensionless pressure and time are obtained for a well discharging steam at a constant mass flow rate for a specified time. The assumptions are made that the steam is in local thermal equilibrium with the reservoir rocks, that temperature changes are due only to phase change, and that effects of vapor-pressure lowering are negligible. Computations show that when a vaporizing liquid phase is present the pressure drawdown exhibits behavior similar to that observed in noncondensable gas reservoirs, but delayed in time. A theoretical analysis allows for the computation of this delay and demonstrates that it is independent of flow geometry. The response that occurs upon pressure buildup is markedly different from that in a noncondensable gas system. This result may provide a diagnostic tool for establishing the existence of phase-change phenomena within a reservoir. ?? 1979.

  7. Structure/processing relationships in vapor-liquid-solid nanowire epitaxy

    E-print Network

    Boles, Steven Tyler

    2010-01-01

    The synthesis of Si and III-V nanowires using the vapor-liquid-solid (VLS) growth mechanism and low-cost Si substrates was investigated. The VLS mechanism allows fabrication of heterostructures which are not readily ...

  8. Z .Fluid Phase Equilibria 161 1999 241256 Vaporliquid equilibrium, fluid state, and zero-pressure solid

    E-print Network

    Lisal, Martin

    Z .Fluid Phase Equilibria 161 1999 241­256 Vapor­liquid equilibrium, fluid state, and zero-pressure but independent constant pressure­constant temperature Z .molecular dynamics simulations of the vapor and liquid. Keywords: Chlorine; Intermolecular potential; Molecular simulation; Vapor­liquid equilibria; Vapor pressure

  9. Simulating vapor-liquid nucleation of n-alkanes

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Siepmann, J. Ilja; Oh, Kwang J.; Klein, Michael L.

    2002-03-01

    A combination of the aggregation-volume-bias Monte Carlo algorithm, the configurational-bias Monte Carlo algorithm, and the umbrella sampling technique was applied to investigate homogeneous vapor-liquid nucleation in ethane, n-butane, and n-heptane. The simple transferable potentials for phase equilibria-united atom (TraPPE-UA) force field was used in this investigation. It was found that for the n-heptane case, the TraPPE-UA force field predicted a nucleation rate that is about three to four orders of magnitude higher than that measured by an upward thermal diffusion cloud chamber experiment. Comparison of the simulation results to the classical nucleation theory (CNT) shows that CNT consistently overestimates the barrier heights for all chain lengths investigated. The offset on the barrier heights was found nearly independent of the supersaturation for both ethane and n-butane, similar to a Lennard-Jones system previously studied. This also directly leads to a good agreement on the cluster sizes between the simulation and the CNT calculated from the nucleation theorem. For n-heptane, however, the offset was found to depend on the supersaturation. It appears that CNT predicts a slightly weaker dependence of the nucleation rate on supersaturation, which agrees with both density functional calculations and the experiments. Structural analysis demonstrates that the orientational order near the surface differs significantly between the critical nucleus and the bulk planar liquid-vapor interface for n-heptane systems, whereas the density in the interior of the critical nucleus is in good agreement with the bulk liquid density. The different surface ordering offers a microscopic explanation for the differences observed for n-heptane between the CNT on one side and experimental observations and simulations on the other side.

  10. Vapor-liquid equilibria of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems

    SciTech Connect

    Mun, S.Y.; Lee, H.

    1999-12-01

    Vapor-liquid equilibrium data of the water + 1,3-propanediol and water + 1,3-propanediol + lithium bromide systems were measured at 60, 160, 300, and 760 mmHg at temperatures ranging from 315 to 488 K. The apparatus used in this work is a modified still especially designed for the measurement of low-pressure VLE, in which both liquid and vapor are continuously recirculated. For the analysis of salt-containing solutions, a method incorporating refractometry and gravimetry was used. From the experimental measurements, the effect of lithium bromide on the VLE behavior of water + 1,3-propanediol was investigated. The experimental data of the salt-free system were successfully correlated using the Wilson, NRTL, and UNIQUAC models. In addition, the extended UNIQUAC model of Sander et al. was applied to the VLE calculation of salt-containing mixtures.

  11. A three-dimensional phase field model for nanowire growth by the vapor-liquid-solid mechanism

    NASA Astrophysics Data System (ADS)

    Wang, Yanming; Ryu, Seunghwa; McIntyre, Paul C.; Cai, Wei

    2014-07-01

    We present a three-dimensional multi-phase field model for catalyzed nanowire (NW) growth by the vapor-liquid-solid (VLS) mechanism. The equation of motion contains both a Ginzburg-Landau term for deposition and a diffusion (Cahn-Hilliard) term for interface relaxation without deposition. Direct deposition from vapor to solid, which competes with NW crystal growth through the molten catalyst droplet, is suppressed by assigning a very small kinetic coefficient at the solid-vapor interface. The thermodynamic self-consistency of the model is demonstrated by its ability to reproduce the equilibrium contact angles at the VLS junction. The incorporation of orientation dependent gradient energy leads to faceting of the solid-liquid and solid-vapor interfaces. The model successfully captures the curved shape of the NW base and the Gibbs-Thomson effect on growth velocity.

  12. Nanophase diagram of binary eutectic Au-Ge nanoalloys for vapor-liquid-solid semiconductor nanowires growth.

    PubMed

    Lu, Haiming; Meng, Xiangkang

    2015-01-01

    Although the vapor-liquid-solid growth of semiconductor nanowire is a non-equilibrium process, the equilibrium phase diagram of binary alloy provides important guidance on the growth conditions, such as the temperature and the equilibrium composition of the alloy. Given the small dimensions of the alloy seeds and the nanowires, the known phase diagram of bulk binary alloy cannot be expected to accurately predict the behavior of the nanowire growth. Here, we developed a unified model to describe the size- and dimensionality-dependent equilibrium phase diagram of Au-Ge binary eutectic nanoalloys based on the size-dependent cohesive energy model. It is found that the liquidus curves reduce and shift leftward with decreasing size and dimensionality. Moreover, the effects of size and dimensionality on the eutectic composition are small and negligible when both components in binary eutectic alloys have the same dimensionality. However, when two components have different dimensionality (e.g. Au nanoparticle-Ge nanowire usually used in the semiconductor nanowires growth), the eutectic composition reduces with decreasing size. PMID:26053237

  13. Nanophase diagram of binary eutectic Au-Ge nanoalloys for vapor-liquid-solid semiconductor nanowires growth

    NASA Astrophysics Data System (ADS)

    Lu, Haiming; Meng, Xiangkang

    2015-06-01

    Although the vapor-liquid-solid growth of semiconductor nanowire is a non-equilibrium process, the equilibrium phase diagram of binary alloy provides important guidance on the growth conditions, such as the temperature and the equilibrium composition of the alloy. Given the small dimensions of the alloy seeds and the nanowires, the known phase diagram of bulk binary alloy cannot be expected to accurately predict the behavior of the nanowire growth. Here, we developed a unified model to describe the size- and dimensionality-dependent equilibrium phase diagram of Au-Ge binary eutectic nanoalloys based on the size-dependent cohesive energy model. It is found that the liquidus curves reduce and shift leftward with decreasing size and dimensionality. Moreover, the effects of size and dimensionality on the eutectic composition are small and negligible when both components in binary eutectic alloys have the same dimensionality. However, when two components have different dimensionality (e.g. Au nanoparticle-Ge nanowire usually used in the semiconductor nanowires growth), the eutectic composition reduces with decreasing size.

  14. Nanophase diagram of binary eutectic Au-Ge nanoalloys for vapor-liquid-solid semiconductor nanowires growth

    PubMed Central

    Lu, Haiming; Meng, Xiangkang

    2015-01-01

    Although the vapor-liquid-solid growth of semiconductor nanowire is a non-equilibrium process, the equilibrium phase diagram of binary alloy provides important guidance on the growth conditions, such as the temperature and the equilibrium composition of the alloy. Given the small dimensions of the alloy seeds and the nanowires, the known phase diagram of bulk binary alloy cannot be expected to accurately predict the behavior of the nanowire growth. Here, we developed a unified model to describe the size- and dimensionality-dependent equilibrium phase diagram of Au-Ge binary eutectic nanoalloys based on the size-dependent cohesive energy model. It is found that the liquidus curves reduce and shift leftward with decreasing size and dimensionality. Moreover, the effects of size and dimensionality on the eutectic composition are small and negligible when both components in binary eutectic alloys have the same dimensionality. However, when two components have different dimensionality (e.g. Au nanoparticle-Ge nanowire usually used in the semiconductor nanowires growth), the eutectic composition reduces with decreasing size. PMID:26053237

  15. Detecting Isobaric VOCs

    SciTech Connect

    Prazeller, Peter; Palmer, Peter T.; Boscaini, Elena; Jobson, B Tom; Alexander, M. Lizabeth

    2003-09-01

    Volatile organic compounds (VOCs) can be monitored by proton transfer reaction (PTR) MS, in which a PTR drift tube is coupled to a quadrupole mass spectrometer. In this technique, compounds undergo proton transfer reactions when they collide with H?O? ions. This soft chemical ionization method, which results in little fragmentation, allows researchers to detect trace levels of VOCs from relatively uncomplicated spectra. Sometimes, the m/z values of VOCs are similar or identical, rendering it impossible to make a positive identification. Thus, Michael Alexander and co-workers at the Pacific Northwest National Laboratory, San Francisco State University, and Innsbruck University (Austria) developed a novel instrument that couples a PTR drift tube to an ion trap mass spectrometer, which can perform MS/MS, to produce characteristic fragments of isobaric species.

  16. Vapor-liquid phase coexistence and transport properties of two-dimensional oligomers

    NASA Astrophysics Data System (ADS)

    Patra, Tarak K.; Hens, Abhiram; Singh, Jayant K.

    2012-08-01

    Grand-canonical transition-matrix Monte Carlo and histogram reweighting techniques are used herein to study the vapor-liquid coexistence properties of two-dimensional (2D) flexible oligomers with varying chain lengths (m = 1-8). The phase diagrams of the various 2D oligomers follow the correspondence state (CS) principle, akin to the behavior observed for bulk oligomers. The 2D critical density is not influenced by the oligomer chain length, which contrasts with the observation for the bulk oligomers. Line tension, calculated using Binder's formalism, in the reduced plot is found to be independent of chain length in contrast to the 3D behavior. The dynamical properties of 2D fluids are evaluated using molecular dynamics simulations, and the velocity and pressure autocorrelation functions are investigated using Green-Kubo (GK) relations to yield the diffusion and viscosity. The viscosity determined from 2D non-equilibrium molecular dynamics simulation is compared with the viscosity estimated from the GK relations. The GK relations prove to be reliable and efficient for the calculation of 2D transport properties. Normal diffusive regions are identified in dense oligomeric fluid systems. The influence of molecular size on the diffusivity and viscosity is found to be diminished at specific CS points for the 2D oligomers considered herein. In contrast, the viscosity and diffusion of the 3D bulk fluid, at a reduced temperature and density, are strongly dependent on the molecular size at the same CS points. Furthermore, the viscosity increases and the diffusion decreases multifold in the 2D system relative to those in the 3D system, at the CS points.

  17. Molecular gas dynamics applied to phase change processes at a vapor-liquid interface: shock-tube experiment and MGD computation for methanol

    NASA Astrophysics Data System (ADS)

    Fujikawa, S.; Yano, T.; Kobayashi, K.; Iwanami, K.; Ichijo, M.

    This paper deals with a molecular gas-dynamics method applied to the accurate determination of the condensation coefficient of methanol vapor. The method consisted of an experiment using a shock tube and computations using a molecular gas-dynamics equation. The experiments were performed in such situations where the shift from a vapor-liquid equilibrium state to a nonequilibrium one is realized by a shock wave in a scale of molecular mean free time of vapor molecules. The temporal evolution in thickness of a liquid film formed on the shock-tube endwall behind a reflected shock wave is measured by an optical interferometer. By comparing the measured liquid-film thickness with numerical solutions for a polyatomic version of the Gaussian-BGK model of the Boltzmann equation, the condensation coefficient of methanol vapor is accurately determined in vapor-liquid nonequilibrium states. As a result, it is clear that the condensation coefficient is just unity very near to an equilibrium state, but is smaller far from the equilibrium state.

  18. Isobaric groundwater well

    DOEpatents

    Hubbell, Joel M. (Idaho Falls, ID); Sisson, James B. (Idaho Falls, ID)

    1999-01-01

    A method of measuring a parameter in a well, under isobaric conditions, including such parameters as hydraulic gradient, pressure, water level, soil moisture content and/or aquifer properties the method as presented comprising providing a casing having first and second opposite ends, and a length between the ends, the casing supporting a transducer having a reference port; placing the casing lengthwise into the well, second end first, with the reference port vented above the water table in the well; and sealing the first end. A system is presented for measuring a parameter in a well, the system comprising a casing having first and second opposite ends, and a length between the ends and being configured to be placed lengthwise into a well second end first; a transducer, the transducer having a reference port, the reference port being vented in the well above the water table, the casing being screened across and above the water table; and a sealing member sealing the first end. In one embodiment, the transducer is a tensiometer transducer and in other described embodiments, another type transducer is used in addition to a tensiometer.

  19. Naturally occurring vapor-liquid-solid (VLS) Whisker growth of germanium sulfide

    USGS Publications Warehouse

    Finkelman, R.B.; Larson, R.R.; Dwornik, E.J.

    1974-01-01

    The first naturally occurring terrestrial example of vapor-liquid-solid (VLS) growth has been observed in condensates from gases released by burning coal in culm banks. Scanning electron microscopy, X-ray diffraction, and energy dispersive analysis indicate that the crystals consist of elongated rods (??? 100 ??m) of germanium sulfide capped by bulbs depleted in germanium. ?? 1974.

  20. Influence of solid-state characteristics on critical parameters of vapor-liquid phase transition

    NASA Astrophysics Data System (ADS)

    Khomkin, A. L.; Shumikhin, A. S.

    2015-11-01

    New method for calculation of critical point parameters and binodal of vapor-liquid (dielectric-metal) phase transition is suggested. Method is based on the hypothesis that cohesion, which determines the main properties of solid state, determines also the properties in vicinity of critical point. Comparison with known experimental data for rare gases and mercury shows satisfactory agreement with our calculations.

  1. Vapor-liquid equilibrium of ethanol by molecular dynamics simulation and Voronoi tessellation.

    PubMed

    Fern, Jared T; Keffer, David J; Steele, William V

    2007-11-22

    Explicit atom simulations of ethanol were performed by molecular dynamics using the OPLS-AA potential. The phase densities were determined self-consistently by comparing the distribution of Voronoi volumes from two-phase and single-phase simulations. This is the first demonstration of the use of Voronoi tessellation in two-phase molecular dynamics simulation of polyatomic fluids. This technique removes all arbitrary determination of the phase diagram by using single-phase simulations to self-consistently validate the probability distribution of Voronoi volumes of the liquid and vapor phases extracted from the two-phase molecular dynamics simulations. Properties from the two phase simulations include critical temperature, critical density, critical pressure, phase diagram, surface tension, and molecule orientation at the interface. The simulations were performed from 375 to 472 K. Also investigated were the vapor pressure and hydrogen bonding along the two phase envelope. The phase envelope agrees extremely well with literature values from GEMC at lower temperatures. The combined use of two-phase molecular dynamics simulation and Voronoi tessellation allows us to extend the phase diagram toward the critical point. PMID:17973521

  2. EXPERIMENTAL MEASUREMENT AND MODELING OF THE VAPOR-LIQUID EQUILIBRIUM OF CARBON DIOXIDE + CHLOROFORM. (R826734)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  3. Universal adsorption at the vapor-liquid interface near the consolute point

    NASA Technical Reports Server (NTRS)

    Schmidt, James W.

    1990-01-01

    The ellipticity of the vapor-liquid interface above mixtures of methylcyclohexane (C7H14) and perfluoromethylcyclohexane (C7F14) has been measured near the consolute point T(c) = 318.6 K. The data are consistent with a model of the interface that combines a short-ranged density-vs height profile in the vapor phase with a much longer-ranged composition-versus-height profile in the liquid. The value of the free parameter produced by fitting the model to the data is consistent with results from two other simple mixtures and a mixture of a polymer and solvent. This experiment combines precision ellipsometry of the vapor-liquid interface with in situ measurements of refractive indices of the liquid phases, and it precisely locates the consolute point.

  4. Steady-state, vapor-liquid concurrent flow: Relative permeabilities and end effects

    SciTech Connect

    Parlar, M.; Zeybek, M.; Yortsos, Y.C.

    1990-06-01

    Steady-state methods are commonly used for the determination of the relative permeabilities of single component vapor-liquid systems, such as steam-water. Even though such experiments are performed under adiabatic conditions, the interpretation of results has proved to be a difficult task in many cases. Reasons involve phase change, heat transfer, capillarity and rate considerations. This paper presents a systematic study of the saturation and temperature distributions in steady-state, vapor-liquid flows and examines the sensitivity to parameters such as injection rate, permeability and core length. Two sets are analyzed, one pertaining to the simultaneous injection of a two-phase mixture (Sanchez and Schechter, 1987) and another involving phase change (liquid to vapor) within the core (Miller, 1951). End effects and, in general, effects associated with capillary heterogeneity are analyzed in detail. 16 refs., 15 figs., 3 tabs.

  5. Metastability of Au-Ge liquid nanocatalysts: Ge vapor-liquid-solid nanowire growth far below the bulk eutectic temperature.

    PubMed

    Adhikari, Hemant; Marshall, Ann F; Goldthorpe, Irene A; Chidsey, Christopher E D; McIntyre, Paul C

    2007-12-01

    The vapor-liquid-solid mechanism of nanowire (NW) growth requires the presence of a liquid at one end of the wire; however, Au-catalyzed Ge nanowire growth by chemical vapor deposition can occur at approximately 100 degrees C below the bulk Au-Ge eutectic. In this paper, we investigate deep sub-eutectic stability of liquid Au-Ge catalysts on Ge NWs quantitatively, both theoretically and experimentally. We construct a binary Au-Ge phase diagram that is valid at the nanoscale and show that equilibrium arguments, based on capillarity, are inconsistent with stabilization of Au-Ge liquid at deep sub-eutectic temperatures, similar to those used in Ge NW growth. Hot-stage electron microscopy and X-ray diffraction are used to test the predictions of nanoscale phase equilibria. In addition to Ge supersaturation of the Au-Ge liquid droplet, which has recently been invoked as an explanation for deep sub-eutectic Ge NW growth, we find evidence of a substantial kinetic barrier to Au solidification during cooling below the nanoscale Au-Ge eutectic temperature. PMID:19206662

  6. Preferred orientations of laterally grown silicon films over amorphous substrates using the vapor–liquid–solid technique

    SciTech Connect

    LeBoeuf, J. L. Brodusch, N.; Gauvin, R.; Quitoriano, N. J.

    2014-12-28

    A novel method has been optimized so that adhesion layers are no longer needed to reliably deposit patterned gold structures on amorphous substrates. Using this technique allows for the fabrication of amorphous oxide templates known as micro-crucibles, which confine a vapor–liquid–solid (VLS) catalyst of nominally pure gold to a specific geometry. Within these confined templates of amorphous materials, faceted silicon crystals have been grown laterally. The novel deposition technique, which enables the nominally pure gold catalyst, involves the undercutting of an initial chromium adhesion layer. Using electron backscatter diffraction it was found that silicon nucleated in these micro-crucibles were 30% single crystals, 45% potentially twinned crystals and 25% polycrystals for the experimental conditions used. Single, potentially twinned, and polycrystals all had an aversion to growth with the (1 0 0) surface parallel to the amorphous substrate. Closer analysis of grain boundaries of potentially twinned and polycrystalline samples revealed that the overwhelming majority of them were of the 60° ?3 coherent twin boundary type. The large amount of coherent twin boundaries present in the grown, two-dimensional silicon crystals suggest that lateral VLS growth occurs very close to thermodynamic equilibrium. It is suggested that free energy fluctuations during growth or cooling, and impurities were the causes for this twinning.

  7. Preferred orientations of laterally grown silicon films over amorphous substrates using the vapor-liquid-solid technique

    NASA Astrophysics Data System (ADS)

    LeBoeuf, J. L.; Brodusch, N.; Gauvin, R.; Quitoriano, N. J.

    2014-12-01

    A novel method has been optimized so that adhesion layers are no longer needed to reliably deposit patterned gold structures on amorphous substrates. Using this technique allows for the fabrication of amorphous oxide templates known as micro-crucibles, which confine a vapor-liquid-solid (VLS) catalyst of nominally pure gold to a specific geometry. Within these confined templates of amorphous materials, faceted silicon crystals have been grown laterally. The novel deposition technique, which enables the nominally pure gold catalyst, involves the undercutting of an initial chromium adhesion layer. Using electron backscatter diffraction it was found that silicon nucleated in these micro-crucibles were 30% single crystals, 45% potentially twinned crystals and 25% polycrystals for the experimental conditions used. Single, potentially twinned, and polycrystals all had an aversion to growth with the {1 0 0} surface parallel to the amorphous substrate. Closer analysis of grain boundaries of potentially twinned and polycrystalline samples revealed that the overwhelming majority of them were of the 60° ?3 coherent twin boundary type. The large amount of coherent twin boundaries present in the grown, two-dimensional silicon crystals suggest that lateral VLS growth occurs very close to thermodynamic equilibrium. It is suggested that free energy fluctuations during growth or cooling, and impurities were the causes for this twinning.

  8. Space cryogenics components based on the thermomechanical effect - Vapor-liquid phase separation

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.; Frederking, T. H. K.

    1989-01-01

    Applications of the thermomechanical effect has been qualified including incorporation in large-scale space systems in the area of vapor-liquid phase separation (VLPS). The theory of the porous-plug phase separator is developed for the limit of a high thermal impedance of the solid-state grains. Extensions of the theory of nonlinear turbulent flow are presented based on experimental results.

  9. On the Electronic Nature of the Surface Potential at the Vapor-Liquid Interface of Water

    SciTech Connect

    Kathmann, S M; Kuo, I; Mundy, C J

    2008-02-05

    The surface potential at the vapor-liquid interface of water is relevant to many areas of chemical physics. Measurement of the surface potential has been experimentally attempted many times, yet there has been little agreement as to its magnitude and sign (-1.1 to +0.5 mV). We present the first computation of the surface potential of water using ab initio molecular dynamics. We find that the surface potential {chi} = -18 mV with a maximum interfacial electric field = 8.9 x 10{sup 7} V/m. A comparison is made between our quantum mechanical results and those from previous molecular simulations. We find that explicit treatment of the electronic density makes a dramatic contribution to the electric properties of the vapor-liquid interface of water. The E-field can alter interfacial reactivity and transport while the surface potential can be used to determine the 'chemical' contribution to the real and electrochemical potentials for ionic transport through the vapor-liquid interface.

  10. Application of an extended Lee-Kesler corresponding-states technique to prediction of vapor-liquid equilibria in multicomponent mixtures containing polar components

    SciTech Connect

    Johnson, J.K.; Rowley, R.L. )

    1989-03-01

    Mixing rules for an extended Lee-Kesler (ELK) corresponding-states method for prediction of thermodynamic properties are presented. The mixing rules, which do not contain adjustable parameters, permit calculation of vapor-liquid equilibria in mixtures containing one or more polar components. While a single heat-of-mixing datum may be included for strongly associating components, generally only pure component properties are used in the calculations. A comparison of calculated bubble-point pressures and equilibrium vaporization ratios to experimental values is made for 26 ternary mixtures (791 points) and 5 quaternary mixtures (175 points). Bubble-point pressures are predicted quite well with ELK (9.1% AAD for ternaries and 7.9% for quaternaries). Composition predictions are difficult to compare in multicomponent systems, but ELK predictions appear to be acceptable on both a system-by-system and an overall AAD basis.

  11. VLS /vapor-liquid-solid/ - Newly discovered growth mechanism on the lunar surface.

    NASA Technical Reports Server (NTRS)

    Carter, J. L.

    1973-01-01

    A probable vapor-liquid-solid (VLS) type of growth has been discovered for the first time in nature on the surface of lunar rock 15015. Scanning electron microprobe and energy dispersive x-ray data indicate that the growth occurs as metallic iron stalks from about 0.015 to 0.15 micrometer in diameter, with bulbous tips consisting of a mixture of iron and sulfur and measuring from about 0.03 to 0.2 micrometer in diameter. The stalk length is two to ten times the bulb diameter.

  12. Low-temperature, vapor-liquid-solid, laterally grown silicon films using alloyed catalysts

    NASA Astrophysics Data System (ADS)

    LeBoeuf, Jerome L.; Brodusch, Nicolas; Gauvin, Raynald; Quitoriano, Nathaniel J.

    2014-12-01

    Using amorphous oxide templates known as micro-crucibles which confine a vapor-liquid-solid catalyst to a specific geometry, two-dimensional silicon thin-films of a single orientation have been grown laterally over an amorphous substrate and defects within crystals have been necked out. The vapor-liquid-solid catalysts consisted nominally of 99% gold with 1% titanium, chromium, or aluminum, and each alloy affected the processing of micro-crucibles and growth within them significantly. It was found that chromium additions inhibited the catalytic effect of the gold catalysts, titanium changed the morphology of the catalyst during processing and aluminum stabilized a potential third phase in the gold-silicon system upon cooling. Two mechanisms for growing undesired nanowires were identified both of which hindered the VLS film growth, fast silane cracking rates and poor gold etching, which left gold nanoparticles near the gold-vapor interface. To reduce the silane cracking rates, growth was done at a lower temperature while an engineered heat and deposition profile helped to reduce NWs caused by the second mechanism. Through experimenting with catalyst compositions, the fundamental mechanisms which produce concentration gradients across the gold-silicon alloy within a given micro-crucible have been proposed. Using the postulated mechanisms, micro-crucibles were designed which promote high-quality, single crystal growth of semiconductors.

  13. Nimbus 7 SMMR derived seasonal variations in the water vapor, liquid water, and surface winds over the global oceans

    NASA Technical Reports Server (NTRS)

    Prabhakara, C.; Short, D. A.

    1984-01-01

    A study based on monthly mean maps of atmospheric water vapor, liquid water, and surface wind derived from Nimbus-7 SMMR over the oceans for 13 months, is examined. A discussion of the retrieval technique used to derive the parameters is presented. The seasonal changes in the strength and position of several of the parameter features are revealed by the December 1978 and June 1979 maps. Zonal averages of the water vapor, liquid water, and surface wind for December and June are compared with information derived from conventional measurements and the results are presented in graphs.

  14. On the existence of vapor-liquid phase transition in dusty plasmas

    NASA Astrophysics Data System (ADS)

    Kundu, M.; Avinash, K.; Sen, A.; Ganesh, R.

    2014-10-01

    The phenomenon of phase transition in a dusty-plasma system (DPS) has attracted some attention in the past. Earlier Farouki and Hamaguchi [J. Chem. Phys. 101, 9876 (1994)] have demonstrated the existence of a liquid to solid transition in DPS where the dust particles interact through a Yukawa potential. However, the question of the existence of a vapor-liquid (VL) transition in such a system remains unanswered and relatively unexplored so far. We have investigated this problem by performing extensive molecular dynamics simulations which show that the VL transition does not have a critical curve in the pressure versus volume diagram for a large range of the Yukawa screening parameter ? and the Coulomb coupling parameter ?. Thus, the VL phase transition is found to be super-critical, meaning that this transition is continuous in the dusty plasma model given by Farouki and Hamaguchi. We provide an approximate analytic explanation of this finding by means of a simple model calculation.

  15. Vapor-Liquid-Solid Etch of Semiconductor Surface Channels by Running Gold Nanodroplets.

    PubMed

    Nikoobakht, Babak; Herzing, Andrew; Muramoto, Shin; Tersoff, Jerry

    2015-12-01

    We show that Au nanoparticles spontaneously move across the (001) surface of InP, InAs, and GaP when heated in the presence of water vapor. As they move, the particles etch crystallographically aligned grooves into the surface. We show that this process is a negative analogue of the vapor-liquid-solid (VLS) growth of semiconductor nanowires: the semiconductor dissolves into the catalyst and reacts with water vapor at the catalyst surface to create volatile oxides, depleting the dissolved cations and anions and thus sustaining the dissolution process. This VLS etching process provides a new tool for directed assembly of structures with sublithographic dimensions, as small as a few nanometers in diameter. Au particles above 100 nm in size do not exhibit this process but remain stationary, with oxide accumulating around the particles. PMID:26599639

  16. Growth mechanisms of vapor-liquid-solid grown nanowires: A detailed analysis of irregular nanowire formation

    NASA Astrophysics Data System (ADS)

    Koto, Makoto

    2014-04-01

    Although vapor-liquid-solid (VLS) growth has become a standard method for producing nanowires, the underlying growth mechanisms have not been fully elucidated because VLS growth is affected by thermodynamic and geometrical factors that, to date, have mainly been considered separately. Based on the assumption that the irregular nanowire growth reflects the conditions of the eutectic droplet during nanowire growth, we aimed to elucidate the thermodynamic and geometrical aspects of the growth mechanisms by the measurement and analysis of irregular kinked and curved Si nanowires grown by Au-catalyzed VLS. The results suggest that kinked nanowires may be caused by higher supersaturation, whereas curved nanowires may be caused by lower supersaturation within the eutectic Au-Si droplet. The results of measuring and analyzing irregular nanowires confirmed that both thermodynamic and geometrical effects complexly influence nanowire growth kinetics, particularly the supersaturation of eutectic droplets, and the effects are more pronounced in larger diameter nanowires.

  17. Glancing angle deposition in a pulsed laser ablation/vapor-liquid-solid grow system

    NASA Astrophysics Data System (ADS)

    Marcu, A.; Stokker, F.; Zamani, R. R.; Lungu, C. P.

    2015-02-01

    A high speed repetition rate laser was used in an 'eclipse' system configuration for growing ZnO nanowires on Au patterned substrates, using vapor-liquid-solid (VLS) technique. Experimental results have shown that the nanowire length increase in the vicinity of catalyst free areas and the grown length distribution over the catalyst covered areas depend on the number of the laser pulses per train. The results suggest that the nanowire over-growth, attributed to the particle surface diffusion, is effective in the ZnO VLS growth within about 100 ?m distances. 'Glancing angle setup' obtained for a submillimeter mask-substrate distance could provide control over VLS growing (or actually over 'non-growing') locations by suppressing the nanowire grow in the center of the catalyst covered areas.

  18. On the existence of vapor-liquid phase transition in dusty plasmas

    SciTech Connect

    Kundu, M.; Sen, A.; Ganesh, R.; Avinash, K.

    2014-10-15

    The phenomenon of phase transition in a dusty-plasma system (DPS) has attracted some attention in the past. Earlier Farouki and Hamaguchi [J. Chem. Phys. 101, 9876 (1994)] have demonstrated the existence of a liquid to solid transition in DPS where the dust particles interact through a Yukawa potential. However, the question of the existence of a vapor-liquid (VL) transition in such a system remains unanswered and relatively unexplored so far. We have investigated this problem by performing extensive molecular dynamics simulations which show that the VL transition does not have a critical curve in the pressure versus volume diagram for a large range of the Yukawa screening parameter ? and the Coulomb coupling parameter ?. Thus, the VL phase transition is found to be super-critical, meaning that this transition is continuous in the dusty plasma model given by Farouki and Hamaguchi. We provide an approximate analytic explanation of this finding by means of a simple model calculation.

  19. Oscillatory Mass Transport in Vapor-Liquid-Solid Growth of Sapphire Nanowires

    SciTech Connect

    Oh, Sang Ho; Chisholm, Matthew F; Kauffmann, Yaron; Kaplan, Prof. Wayne D.; Luo, Weidong; Ruhle, M.; Scheu, Christina

    2010-01-01

    In vapor-liquid-solid (VLS) growth, the liquid phase plays a pivotal role in mediating mass transport from the vapor source to the growth front of a nanowire. Such transport often takes place through the liquid phase. However, we observed by in situ transmission electron microscopy a different behavior for self-catalytic VLS growth of sapphire nanowires. The growth occurs in a layer-by-layer fashion and is accomplished by interfacial diffusion of oxygen through the ordered liquid aluminum atoms. Oscillatory growth and dissolution reactions at the top rim of the nanowires occur and supply the oxygen required to grow a new (0006) sapphire layer. A periodic modulation of the VLS triple-junction configuration accompanies these oscillatory reactions.

  20. Broad compositional tunability of indium tin oxide nanowires grown by the vapor-liquid-solid mechanism

    SciTech Connect

    Zervos, M. Giapintzakis, J.; Mihailescu, C. N.; Luculescu, C. R.; Florini, N.; Komninou, Ph.; Kioseoglou, J.; Othonos, A.

    2014-05-01

    Indium tin oxide nanowires were grown by the reaction of In and Sn with O{sub 2} at 800?°C via the vapor-liquid-solid mechanism on 1 nm Au/Si(001). We obtain Sn doped In{sub 2}O{sub 3} nanowires having a cubic bixbyite crystal structure by using In:Sn source weight ratios > 1:9 while below this we observe the emergence of tetragonal rutile SnO{sub 2} and suppression of In{sub 2}O{sub 3} permitting compositional and structural tuning from SnO{sub 2} to In{sub 2}O{sub 3} which is accompanied by a blue shift of the photoluminescence spectrum and increase in carrier lifetime attributed to a higher crystal quality and Fermi level position.

  1. Atomic characterization of Au clusters in vapor-liquid-solid grown silicon nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Wanghua; Pareige, Philippe; Castro, Celia; Xu, Tao; Grandidier, Bruno; Stiévenard, Didier; Roca i Cabarrocas, Pere

    2015-09-01

    By correlating atom probe tomography with other conventional microscope techniques (scanning electron microscope, scanning transmission electron microscope, and scanning tunneling microscopy), the distribution and composition of Au clusters in individual vapor-liquid-solid grown Si nanowires is investigated. Taking advantage of the characteristics of atom probe tomography, we have developed a sample preparation method by inclining the sample at certain angle to characterize the nanowire sidewall without using focused ion beam. With three-dimensional atomic scale reconstruction, we provide direct evidence of Au clusters tending to remain on the nanowire sidewall rather than being incorporated into the Si nanowires. Based on the composition measurement of Au clusters (28% ± 1%), we have demonstrated the supersaturation of Si atoms in Au clusters, which supports the hypothesis that Au clusters are formed simultaneously during nanowire growth rather than during the cooling process.

  2. Deterministic Nucleation of InP on Metal Foils with the Thin-Film Vapor-Liquid-Solid Growth Mode

    E-print Network

    Javey, Ali

    Deterministic Nucleation of InP on Metal Foils with the Thin-Film Vapor-Liquid-Solid Growth Mode demonstrated growth of poly crystalline InP thin films with grain sizes >100 m on nonepitaxial substrates using at the growth temperatures, causing supersaturation of the liquid In and inducing precipitation of solid InP

  3. n-Type Doping of Vapor-Liquid-Solid Grown GaAs Nanowires

    NASA Astrophysics Data System (ADS)

    Gutsche, Christoph; Lysov, Andrey; Regolin, Ingo; Blekker, Kai; Prost, Werner; Tegude, Franz-Josef

    2011-12-01

    In this letter, n-type doping of GaAs nanowires grown by metal-organic vapor phase epitaxy in the vapor-liquid-solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations N D of GaAs nanowires are found to vary from 7 × 1017 cm-3 to 2 × 1018 cm-3. The n-type conductivity is proven by the transfer characteristics of fabricated nanowire metal-insulator-semiconductor field-effect transistor devices.

  4. Thermodynamic models for vapor-liquid equilibria of nitrogen + oxygen + carbon dioxide at low temperatures

    NASA Astrophysics Data System (ADS)

    Vrabec, Jadran; Kedia, Gaurav Kumar; Buchhauser, Ulrich; Meyer-Pittroff, Roland; Hasse, Hans

    2009-02-01

    For the design and optimization of CO 2 recovery from alcoholic fermentation processes by distillation, models for vapor-liquid equilibria (VLE) are needed. Two such thermodynamic models, the Peng-Robinson equation of state (EOS) and a model based on Henry's law constants, are proposed for the ternary mixture N 2 + O 2 + CO 2. Pure substance parameters of the Peng-Robinson EOS are taken from the literature, whereas the binary parameters of the Van der Waals one-fluid mixing rule are adjusted to experimental binary VLE data. The Peng-Robinson EOS describes both binary and ternary experimental data well, except at high pressures approaching the critical region. A molecular model is validated by simulation using binary and ternary experimental VLE data. On the basis of this model, the Henry's law constants of N 2 and O 2 in CO 2 are predicted by molecular simulation. An easy-to-use thermodynamic model, based on those Henry's law constants, is developed to reliably describe the VLE in the CO 2-rich region.

  5. Controlled Growth of Organic Semiconductor Films Using Electrospray Vapor-Liquid-Solid Deposition

    NASA Astrophysics Data System (ADS)

    Shaw, Daniel; Bufkin, Kevin; Johnson, Brad; Patrick, David

    2010-03-01

    Interest in low molecular weight organic semiconductors (OS) for applications such as light-emitting diodes, photovoltaics, and other technologies stems in part from their prospects for enabling significantly reduced manufacturing costs compared to traditional inorganic semiconductors. However many of the best performing prototype devices produced so far have involved expensive or time-consuming fabrication methods, such as the use of single crystals or thin films deposited under high vacuum conditions. New methods are needed capable of rapidly and inexpensively producing high quality polycrystalline films, preferably involving near-ambient conditions. This poster will present studies of one such approach based on an electrospray vapor-liquid-solid growth technique. The method produces polycrystalline OS films deposited via atmospheric-pressure sublimation from a carrier gas (argon) which is partially ionized by a corona discharge. Vapor-phase molecules are then attracted to a charged substrate coated with a thin liquid solvent layer, in which they dissolve and grow as crystals, producing films with large grain sizes. This poster will describe the electrostatic and hydrodynamic features of the deposition mechanism, and the growth kinetics of the resulting polycrystalline films.

  6. Organic-vapor-liquid-solid deposition with an impinging gas jet

    NASA Astrophysics Data System (ADS)

    Shaw, Daniel W.; Bufkin, Kevin; Baronov, Alexandr A.; Johnson, Brad L.; Patrick, David L.

    2012-04-01

    A method for rapid, mass-efficient deposition of highly crystalline organic films under near ambient conditions of pressure and temperature is reported based on delivery of an organic precursor via an impinging gas jet to a substrate coated by a thin liquid solvent layer. Films of the organic semiconductor tetracene were deposited by sublimation into a flow of argon carrier gas directed at an indium-tin-oxide/glass substrate coated by a thin layer of bis(2-ethylhexyl)sebecate, and growth was followed in situ with optical microscopy. A fluid dynamics model is applied to account for the gas phase transport and aggregation, and the results compared to experiment. The combination of gas jet delivery with an organic-vapor-liquid-solid growth mechanism leads to larger crystals and lower nucleation densities than on bare surfaces, with markedly different nucleation and growth kinetics. An explanation based on enhanced solution-phase diffusivity and a larger critical nucleus size in the liquid layer is proposed to account for the differences.

  7. Vapor-liquid equilibria simulation and an equation of state contribution for dipole-quadrupole interactions.

    PubMed

    Vrabec, Jadran; Gross, Joachim

    2008-01-10

    A systematic investigation on vapor-liquid equilibria (VLEs) of dipolar and quadrupolar fluids is carried out by molecular simulation to develop a new Helmholtz energy contribution for equations of state (EOSs). Twelve two-center Lennard-Jones plus point dipole and point quadrupole model fluids (2CLJDQ) are studied for different reduced dipolar moments micro*2=6 or 12, reduced quadrupolar moments Q*2=2 or 4 and reduced elongations L*=0, 0.505, or 1. Temperatures cover a wide range from about 55% to 95% of the critical temperature of each fluid. The NpT+test particle method is used for the calculation of vapor pressure, saturated densities, and saturated enthalpies. Critical data and the acentric factor are obtained from fits to the simulation data. On the basis of this data, an EOS contribution for the dipole-quadrupole cross-interactions of nonspherical molecules is developed. The expression is based on a third-order perturbation theory, and the model constants are adjusted to the present 2CLJDQ simulation results. When applied to mixtures, the model is found to be in excellent agreement with results from simulation and experiment. The new EOS contribution is also compatible with segment-based EOS, such as the various forms of the statistical associating fluid theory EOS. PMID:18072758

  8. Fabrication and performance evaluation of a high temperature co-fired ceramic vaporizing liquid microthruster

    NASA Astrophysics Data System (ADS)

    How Cheah, Kean; Low, Kay-Soon

    2015-01-01

    This paper presents the study of a microelectromechanical system (MEMS)-scaled microthruster using ceramic as the structural material. A vaporizing liquid microthruster (VLM) has been fabricated using the high temperature co-fired ceramic (HTCC) technology. The developed microthruster consists of five components, i.e. inlet, injector, vaporizing chamber, micronozzle and microheater, all integrated in a chip with a dimension of 30?mm × 26?mm × 8?mm. In the dry test, the newly developed microheater which is deposited on zirconia substrate consumes 21% less electrical power than those deposited on silicon substrate to achieve a temperature of 100?°C. Heating temperature as high as 409.1?°C can be achieved using just 5?W of electrical power. For simplicity and safety, a functional test of the VLM with water as propellant has been conducted in the laboratory. Full vaporization of water propellant feeding at different flow rates has been successfully demonstrated. A maximum thrust of 633.5?µN at 1?µl?s-1 propellant consumption rate was measured using a torsional thrust stand.

  9. Rational Concept for Designing Vapor-Liquid-Solid Growth of Single Crystalline Metal Oxide Nanowires.

    PubMed

    Klamchuen, Annop; Suzuki, Masaru; Nagashima, Kazuki; Yoshida, Hideto; Kanai, Masaki; Zhuge, Fuwei; He, Yong; Meng, Gang; Kai, Shoichi; Takeda, Seiji; Kawai, Tomoji; Yanagida, Takeshi

    2015-10-14

    Metal oxide nanowires hold great promise for various device applications due to their unique and robust physical properties in air and/or water and also due to their abundance on Earth. Vapor-liquid-solid (VLS) growth of metal oxide nanowires offers the high controllability of their diameters and spatial positions. In addition, VLS growth has applicability to axial and/or radial heterostructures, which are not attainable by other nanowire growth methods. However, material species available for the VLS growth of metal oxide nanowires are substantially limited even though the variety of material species, which has fascinating physical properties, is the most interesting feature of metal oxides. Here we demonstrate a rational design for the VLS growth of various metal oxide nanowires, based on the "material flux window". This material flux window describes the concept of VLS nanowire growth within a limited material flux range, where nucleation preferentially occurs only at a liquid-solid interface. Although the material flux was previously thought to affect primarily the growth rate, we experimentally and theoretically demonstrate that the material flux is the important experimental variable for the VLS growth of metal oxide nanowires. On the basis of the material flux window concept, we discover novel metal oxide nanowires, composed of MnO, CaO, Sm2O3, NiO, and Eu2O3, which were previously impossible to form via the VLS route. The newly grown NiO nanowires exhibited stable memristive properties superior to conventional polycrystalline devices due to the single crystallinity. Thus, this VLS design route offers a useful guideline for the discovery of single crystalline nanowires that are composed of functional metal oxide materials. PMID:26372675

  10. Momentum distribution of Delta- isobar in closed shell nuclei

    E-print Network

    A. N. Tabachenko

    2005-12-26

    One Delta- isobar components of the wave function in closed shell nuclei are considered within the framework of the harmonic oscillator model. Conventional transition potential is the pi- and rho- exchange potential. On the basis of the Delta- isobar configuration wave function, the momentum distribution of the Delta- isobar is calculated for the light nuclei $^4 He$,$^{16}O$,$^{12}C$

  11. Experimental measurements of vapor-liquid equilibria of the H2O + CO2 + CH4 ternary system

    USGS Publications Warehouse

    Qin, J.; Rosenbauer, R.J.; Duan, Zhenhao

    2008-01-01

    Reported are the experimental measurements on vapor-liquid equilibria in the H2O + CO2 + CH4 ternary system at temperatures from (324 to 375) K and pressures from (10 to 50) MPa. The results indicate that the CH4 solubility in the ternary mixture is about 10 % to 40 % more than that calculated by interpolation from the Henry's law constants of the binary system, H2O + CH4, and the solubility of CO2 is 6 % to 20 % more than what is calculated by the interpolation from the Henry's law constants of the binary mixture, H 2O + CO2. ?? 2008 American Chemical Society.

  12. Engineering scale development of the Vapor-Liquid-Solid (VLS) process for the production of silicon carbide fibrils

    SciTech Connect

    Hollar, W.E. Jr.; Mills, W.H.

    1993-09-01

    Vapor-liquid-solid (VLS)SiC fibrils are used as reinforcement in ceramic matrix composites (CMC). A program has been completed for determining process scaleup parameters and to produce material for evaluation in a CMC. The scaleup is necessary to lower production cost and increase material availability. Scaleup parameters were evaluated in a reactor with a vertical dimension twice that of the LANL reactor. Results indicate that the scaleup will be possible. Feasibility of recycling process gas was demonstrated and the impact of postprocessing on yields determined.

  13. Isobar Separator for Anions: Current status

    NASA Astrophysics Data System (ADS)

    Alary, Jean-François; Javahery, Gholamreza; Kieser, William; Zhao, Xiao-Lei; Litherland, Albert; Cousins, Lisa; Charles, Christopher

    2015-10-01

    The Isobar Separator for Anions (ISA) is an emerging separation technique of isobars applied first to the selective removal of 36S from 36Cl, achieving a relative suppression ratio of 6 orders of magnitude. Using a radio-frequency quadrupole (RFQ) column incorporating low energy gas cells, this innovative technique enables the use of a wide range of low energy ion-molecule reactions and collisional-induced dissociation processes for suppressing specific atomic of molecular anions with a high degree of selectivity. Other elemental pairs (analyte/isobar) successfully separated at AMS level include Ca/K, Sr/(Y, Zr), Cs/Ba, Hf/W and Pu/U. In view of these initial successes, an effort to develop a version of the ISA that can be used as a robust technique for routine AMS analysis has been undertaken. We will discuss the detailed layout of a practical ISA and the functional requirements that a combined ISA/AMS should meet. These concepts are currently being integrated in a pre-commercial ISA system that will be installed soon at the newly established A.E. Lalonde Laboratory in Ottawa, Canada.

  14. Shadowing and mask opening effects during selective-area vapor-liquid-solid growth of InP nanowires by metalorganic molecular beam epitaxy.

    PubMed

    Kelrich, A; Calahorra, Y; Greenberg, Y; Gavrilov, A; Cohen, S; Ritter, D

    2013-11-29

    Indium phosphide nanowires were grown by metalorganic molecular beam epitaxy using the selective-area vapor-liquid-solid method. We show experimentally and theoretically that the size of the annular opening around the nanowire has a major impact on nanowire growth rate. In addition, we observed a considerable reduction of the growth rate in dense two-dimensional arrays, in agreement with a calculation of the shadowing of the scattered precursors. Due to the impact of these effects on growth, they should be considered during selective-area vapor-liquid-solid nanowire epitaxy. PMID:24177750

  15. A model used for Hugoniot prediction of material at high-temperature along isobaric path

    NASA Astrophysics Data System (ADS)

    Zhou, Qiang; Chen, Pengwan; Ma, Danzhu; Dai, Kaida

    2013-07-01

    A model was derived in this paper to calculate the high-temperature Hugoniot of solid material along isobaric path by using an enthalpy-based equation of state (EOS) model. It provides a way and complements the Mie-Grüneisen EOS for studying high-temperature Hugoniot of materials. The Hugoniot of tungsten at 1223 K in moderate pressure range (0-10 GPa) and the Hugoniot of molybdenum at 1673 K in high pressure range (10˜300 GPa) were calculated using the presented model. The calculated results fit in with the literature data. The model can satisfactorily predict the Hugoniot of solid at high temperature over a wide pressure range. The model was also extended to predict the Hugoniot of porous materials with high initial temperature along isobaric path; and the Hugoniots of multi-component solids and porous materials at high temperature were also calculated combining with the pressure equilibrium method.

  16. VAPOR/LIQUID EQUILIBRIA OF CONSTITUENTS FROM COAL GASIFICATION IN REFRIGERATED METHANOL

    EPA Science Inventory

    The report describes a thermodynamic framework, established for the development of a model of the phase equilibria of mixtures of methanol and the major constituents found in gases produced from coal. Two approaches were used to model the equilibrium behavior: (1) an equation of ...

  17. The system NaCl-H2O: relations of vapor-liquid near the critical temperature of water and of vapor-liquid-halite from 300° to 500°C

    USGS Publications Warehouse

    Bischoff, James L.; Rosenbauer, Robert J.; Pitzer, Kenneth S.

    1986-01-01

    Vapor-liquid relations (P-T-x) for the system NaCl-H2O were determined experimentally at temperatures spanning the critical temperature of water (Tc), the lowest temperature in the system at which critical behavior occurs. In addition, vapor-liquid-halite P-T-x(vapor) relations were determined from 300° to 500°C. Results show that at 373.0°C, immediately below Tc, the vapor side of the isothermal vaporliquid P-x boundary has a shape quite different from that previously conceived. The NaCl content of the vapor increases with pressure in a smooth manner from the pressure of the three-phase assemblage (135 bars, 0.0029% NaCl), to a pressure just below that of the vapor pressure of pure water (0.012% NaCl at 184 bars). Above this pressure the boundary abruptly reverses and projects asymptotically to 0% NaCl in a beak-like shape at 218 bars, the vapor pressure of pure water. At 375.5°, slightly above Tc, the asymptote disappears, and is replaced by a rounded nose. At progressively higher temperatures, the nose disappears and by 380°C the familiar symmetrical bell-shaped curve predominates with the critical point defined by the top of the bell. The P-T curve of the three-phase assemblage determined in the present study is in agreement with previous workers. The NaCl content of the three-phase vapor, however, is much higher than some literature values at temperatures above 410°C.

  18. Vertically Aligned Ge Nanowires on Flexible Plastic Films Synthesized by (111)-Oriented Ge Seeded Vapor-Liquid-Solid Growth.

    PubMed

    Toko, Kaoru; Nakata, Mitsuki; Jevasuwan, Wipakorn; Fukata, Naoki; Suemasu, Takashi

    2015-08-19

    Transfer-free fabrication of vertical Ge nanowires (NWs) on a plastic substrate is demonstrated using a vapor-liquid-solid (VLS) method. The crystal quality of Ge seed layers (50 nm thickness) prepared on plastic substrates strongly influenced the VLS growth morphology, i.e., the density, uniformity, and crystal quality of Ge NWs. The metal-induced layer exchange yielded a (111)-oriented Ge seed layer at 325 °C, which allowed for the VLS growth of vertically aligned Ge NWs. The Ge NW array had almost the same quality as that formed on a bulk Ge(111) substrate. Transmission electron microscopy demonstrated that the Ge NWs were defect-free single crystals. The present investigation paves the way for advanced electronic optical devices integrated on a low-cost flexible substrate. PMID:26230716

  19. Structural and electronic properties of InN nanowire network grown by vapor-liquid-solid method

    NASA Astrophysics Data System (ADS)

    Barick, B. K.; Rodríguez-Fernández, Carlos; Cantarero, Andres; Dhar, S.

    2015-05-01

    Growth of InN nanowires have been carried out on quartz substrates at different temperatures by vapor-liquid-solid (VLS) technique using different thicknesses of Au catalyst layer. It has been found that a narrow window of Au layer thickness and growth temperature leads to multi-nucleation, in which each site acts as the origin of several nanowires. In this multi-nucleation regime, several tens of micrometer long wires with diameter as small as 20 nm are found to grow along [ 11 2 ¯ 0 ] direction (a-plane) to form a dense network. Structural and electronic properties of these wires are studied. As grown nanowires show degenerate n-type behavior. Furthermore, x-ray photoemission study reveals an accumulation of electrons on the surface of these nanowires. Interestingly, the wire network shows persistence of photoconductivity for several hours after switching off the photoexcitation.

  20. VaporLiquidSolid and VaporSolid Growth of Phase-Change Sb2Te3 Nanowires and Sb2Te3/GeTe Nanowire

    E-print Network

    Yu, Dong

    Vapor­Liquid­Solid and Vapor­Solid Growth of Phase-Change Sb2Te3 Nanowires and Sb2Te3/GeTe Nanowire as an improved synthesis of Sb2Te3 nanowires. The synthesis of the heterostructures employs Au nanowires and nanowire heterostructures demonstrates that these nanostructures exhibit memory

  1. QUANTITY: An Isobaric Tag for Quantitative Glycomics

    PubMed Central

    Yang, Shuang; Wang, Meiyao; Chen, Lijun; Yin, Bojiao; Song, Guoqiang; Turko, Illarion V.; Phinney, Karen W.; Betenbaugh, Michael J.; Zhang, Hui; Li, Shuwei

    2015-01-01

    Glycan is an important class of macromolecules that play numerous biological functions. Quantitative glycomics - analysis of glycans at global level - however, is far behind genomics and proteomics owing to technical challenges associated with their chemical properties and structural complexity. As a result, technologies that can facilitate global glycan analysis are highly sought after. Here, we present QUANTITY (Quaternary Amine Containing Isobaric Tag for Glycan), a quantitative approach that can not only enhance detection of glycans by mass spectrometry, but also allow high-throughput glycomic analysis from multiple biological samples. This robust tool enabled us to accomplish glycomic survey of bioengineered Chinese Hamster Ovary (CHO) cells with knock-in/out enzymes involved in protein glycosylation. Our results demonstrated QUANTITY is an invaluable technique for glycan analysis and bioengineering. PMID:26616285

  2. An Isobaric Model for Kaon photoproduction

    E-print Network

    Han, B S; Kim, K S; Cheon, I T; Han, Bong Soo; Cheoun, Myung Ki; Cheon, Il-Tong

    1999-01-01

    The kaon photoproduction is analyzed up to $E_\\gamma^{\\rm Lab}$=2.0 GeV by using an isobaric model based on effective Lagrangians and by taking a cross symmetry into account. Both {\\it pseudovector} and {\\it pseudoscalar} couplings for kaon-baryon-baryon (baryon spin=1/2) interactions are considered with form factors. A vector meson($K^*(890)$), an axial vector meson($K_1(1270)$), nucleon resonances($J\\le5/2$), and hyperon resonances($J\\le3/2$) are treated as participating particles. By determining unknown coupling constants through a systematic fitting of the differential cross section, the total cross section, the single polarization observable, and the radiative kaon capture branching ratio to their experimental data, we find out a simple model which reproduces all the experimental data well.

  3. Diffusion suppression in vapor-liquid-solid Si nanowire growth by a barrier layer between the Au catalyst and substrate

    NASA Astrophysics Data System (ADS)

    Koto, Makoto; Watanabe, Masatoshi; Sugawa, Etsuko; Shimizu, Tomohiro; Shingubara, Shoso

    2014-10-01

    Nanowires have attracted significant interest because of their unique characteristics. Vapor-liquid-solid (VLS) growth is the standard method for fabricating nanowires and Au is the most commonly used catalyst. However, Au catalyst droplets diffuse over the Si substrate surface with a high migration velocity and agglomerate at relatively low temperatures. In our previous work, we reported a significant improvement in the positioning and diameter distribution of VLS-grown Si nanowires by inserting a diffusion barrier layer and concluded that the barrier layer suppressed the formation of AuSi eutectic droplets and prevented the droplets diffusing on the substrate surface during nucleation. In the present study, we analyzed the nucleation of the Au catalyst and examined its behavior during nucleation. Detailed multidirectional analysis and in situ observations confirmed that the formation and agglomeration of AuSi eutectic droplets was suppressed by the formation of a silicide layer. This because of the higher reaction temperatures between the diffusion barrier and the substrate silicon, and between the catalyst and the diffusion barrier, compared with the reaction between the Au catalyst and substrate silicon.

  4. Effects of nitrogen precursor on the Au-assisted vapor-liquid-solid growth of GaAs(N) nanostructures

    NASA Astrophysics Data System (ADS)

    Suzuki, Hidetoshi; Sakai, Kentaro; Haraguchi, Tomohiro; Yamauchi, Toshihiro; Hijii, Masanobu; Maeda, Kouji; Ikari, Tetsuo

    2014-01-01

    We investigated the effects of the use of a N precursor on the morphology of GaAs(N) nanostructures grown on GaAs (0 0 1) substrates via the vapor-liquid-solid (VLS) method while using Au particles as the catalyst. The synthesized nanostructures were characterized using scanning electron microscopy and X-ray diffraction analyses. When the N precursor was not used, GaAs nanowires grew, mainly along the <1 1 1>A directions, on the surface of the substrate. These nanowires consisted of zincblende (ZB) and wurtzite (WZ) structures, with a number of boundaries being formed at the {1 1 1} planes. When the N precursor was used, isotropic GaAsN nanodots in which 1 2% of the As atoms had been substituted by N atoms were formed. These nanodots consisted of ZB structures having twin boundaries; no WZ structures were formed in this case. Finally, although they remained isotropic in shape, the nanodots grew in a direction along which the substrate was oriented.

  5. Vapor-liquid partitioning of alkaline earth and transition metals in NaCl-dominated hydrothermal fluids: An experimental study from 360 to 465 °C, near-critical to halite saturated conditions

    NASA Astrophysics Data System (ADS)

    Pester, Nicholas J.; Ding, Kang; Seyfried, William E.

    2015-11-01

    Multi-phase fluid flow is a common occurrence in magmatic hydrothermal systems; and extensive modeling efforts using currently established P-V-T-x properties of the NaCl-H2O system are impending. We have therefore performed hydrothermal flow experiments (360-465 °C) to observe vapor-liquid partitioning of alkaline earth and first row transition metals in NaCl-dominated source solutions. The data allow extraction of partition coefficients related to the intrinsic changes in both chlorinity and density along the two-phase solvus. The coefficients yield an overall decrease in vapor affinity in the order Cu(I) > Na > Fe(II) > Zn > Ni(II) ? Mg ? Mn(II) > Co(II) > Ca > Sr > Ba, distinguished with 95% confidence for vapor densities greater than ?0.2 g/cm3. The alkaline earth metals are limited to purely electrostatic interactions with Cl ligands, resulting in an excellent linear correlation (R2 > 0.99) between their partition coefficients and respective ionic radii. Though broadly consistent with this relationship, relative behavior of the transition metals is not well resolved, being likely obscured by complex bonding processes and the potential participation of Na in the formation of tetra-chloro species. At lower densities (at/near halite saturation) partitioning behavior of all metals becomes highly non-linear, where M/Cl ratios in the vapor begin to increase despite continued decreases in chlorinity and density. We refer to this phenomenon as "volatility", which is broadly associated with substantial increases in the HCl/NaCl ratio (eventually to >1) due to hydrolysis of NaCl. Some transition metals (e.g., Fe, Zn) exhibit volatility prior to halite stability, suggesting a potential shift in vapor speciation relative to nearer critical regions of the vapor-liquid solvus. The chemistry of deep-sea hydrothermal fluids appears affected by this process during magmatic events, however, our results do not support suggestions of subseafloor halite precipitation recorded in currently available field data. Ca-Cl systematics in vent fluids are specifically explored, revealing behavior consistent with partitioning due to phase separation. Interestingly, the effect of variable chloride on dissolved Na/Ca ratios associated with plagioclase solubility (in single-phase solutions) appears fundamentally similar to that of phase separation on vapor compositions such that vapors evolved in hydrothermal systems may naturally remain near equilibrium with the host lithology. Conversely, residual liquids/brines left behind in the crust may be undersaturated with metals, enhancing the rate and extent of hydrothermal alteration.

  6. Isobaric Labeling-Based Relative Quantification in Shotgun Proteomics

    PubMed Central

    2015-01-01

    Mass spectrometry plays a key role in relative quantitative comparisons of proteins in order to understand their functional role in biological systems upon perturbation. In this review, we review studies that examine different aspects of isobaric labeling-based relative quantification for shotgun proteomic analysis. In particular, we focus on different types of isobaric reagents and their reaction chemistry (e.g., amine-, carbonyl-, and sulfhydryl-reactive). Various factors, such as ratio compression, reporter ion dynamic range, and others, cause an underestimation of changes in relative abundance of proteins across samples, undermining the ability of the isobaric labeling approach to be truly quantitative. These factors that affect quantification and the suggested combinations of experimental design and optimal data acquisition methods to increase the precision and accuracy of the measurements will be discussed. Finally, the extended application of isobaric labeling-based approach in hyperplexing strategy, targeted quantification, and phosphopeptide analysis are also examined. PMID:25337643

  7. The ILIAS project for selective isobar suppression by laser photodetachment

    NASA Astrophysics Data System (ADS)

    Forstner, Oliver; Andersson, Pontus; Hanstorp, Dag; Lahner, Johannes; Martschini, Martin; Pitters, Johanna; Priller, Alfred; Steier, Peter; Golser, Robin

    2015-10-01

    Laser photodetachment is the process when the extra electron of a negative ion is removed by means of laser radiation. This can happen only if the photon energy is larger than the electron affinity of the ion. The process can be used in mass spectrometry to selectively suppress unwanted isobars, provided that the electron affinity of the unwanted isobar is lower than that of the isobar under investigation. At the Ion Laser InterAction Setup (ILIAS) at the University of Vienna laser photodetachment of negative atomic and molecular ions is studied and its applicability for selective isobar suppression in accelerator mass spectrometry (AMS) is evaluated. The setup provides mass separated beams of negative ions with energies up to 30 keV. Negative ions are produced in a Middleton type cesium sputter ion source, mass selected and overlapped with a strong continuous wave laser beam. In order to extend the interaction time of ions and laser, the ion beam is decelerated to thermal energies in a gas-filled radio frequency quadrupole cooler. For an appropriate choice of the photon energy, unwanted isobars are neutralized while the isobar of interest is unaffected and remains negatively charged. A description of the ILIAS setup and results from the commissioning phase of the RFQ cooler are presented. Up to 8% ion beam transmission could be achieved after a recent redesign of the extraction system. Furthermore first results of photodetachment experiments of 63Cu- within the RFQ cooler are presented.

  8. A flux induced crystal phase transition in the vapor-liquid-solid growth of indium-tin oxide nanowires

    NASA Astrophysics Data System (ADS)

    Meng, Gang; Yanagida, Takeshi; Yoshida, Hideto; Nagashima, Kazuki; Kanai, Masaki; Zhuge, Fuwei; He, Yong; Klamchuen, Annop; Rahong, Sakon; Fang, Xiaodong; Takeda, Seiji; Kawai, Tomoji

    2014-05-01

    Single crystalline metal oxide nanowires formed via a vapor-liquid-solid (VLS) route provide a platform not only for studying fundamental nanoscale properties but also for exploring novel device applications. Although the crystal phase variation of metal oxides, which exhibits a variety of physical properties, is an interesting feature compared with conventional semiconductors, it has been difficult to control the crystal phase of metal oxides during the VLS nanowire growth. Here we show that a material flux critically determines the crystal phase of indium-tin oxide nanowires grown via the VLS route, although thermodynamical parameters, such as temperature and pressure, were previously believed to determine the crystal phase. The crystal phases of indium-tin oxide nanowires varied from the rutile structures (SnO2), the metastable fluorite structures (InxSnyO3.5) and the bixbyite structures (Sn-doped In2O3) when only the material flux was varied within an order of magnitude. This trend can be interpreted in terms of the material flux dependence of crystal phases (rutile SnO2 and bixbyite In2O3) on the critical nucleation at the liquid-solid (LS) interface. Thus, precisely controlling the material flux, which has been underestimated for VLS nanowire growths, allows us to design the crystal phase and properties in the VLS nanowire growth of multicomponent metal oxides.Single crystalline metal oxide nanowires formed via a vapor-liquid-solid (VLS) route provide a platform not only for studying fundamental nanoscale properties but also for exploring novel device applications. Although the crystal phase variation of metal oxides, which exhibits a variety of physical properties, is an interesting feature compared with conventional semiconductors, it has been difficult to control the crystal phase of metal oxides during the VLS nanowire growth. Here we show that a material flux critically determines the crystal phase of indium-tin oxide nanowires grown via the VLS route, although thermodynamical parameters, such as temperature and pressure, were previously believed to determine the crystal phase. The crystal phases of indium-tin oxide nanowires varied from the rutile structures (SnO2), the metastable fluorite structures (InxSnyO3.5) and the bixbyite structures (Sn-doped In2O3) when only the material flux was varied within an order of magnitude. This trend can be interpreted in terms of the material flux dependence of crystal phases (rutile SnO2 and bixbyite In2O3) on the critical nucleation at the liquid-solid (LS) interface. Thus, precisely controlling the material flux, which has been underestimated for VLS nanowire growths, allows us to design the crystal phase and properties in the VLS nanowire growth of multicomponent metal oxides. Electronic supplementary information (ESI) available: STEM mapping of In and Sn in an ISO nanowire (Fig. S1) and homogeneity of a fluorite ISO phase at the full length of a nanowire (Fig. S2). See DOI: 10.1039/c4nr01016g

  9. Analysis of the vapor-liquid-solid mechanism for nanowire growth and a model for this mechanism.

    PubMed

    Mohammad, S Noor

    2008-05-01

    The vapor-liquid-solid (VLS) mechanism is most widely employed to grow nanowires (NWs). The mechanism uses foreign element catalytic agent (FECA) to mediate the growth. Because of this, it is believed to be very stable with the FECA-mediated droplets not consumed even when reaction conditions change. Recent experiments however differ, which suggest that even under cleanest growth conditions, VLS mechanism may not produce long, thin, uniform, single-crystal nanowires of high purity. The present investigation has addressed various issues involving fundamentals of VLS growth. While addressing these issues, it has taken into consideration the influence of the electrical, hydrodynamic, thermodynamic, and surface tension effects on NW growth. It has found that parameters such as mesoscopic effects on nanoparticle seeds, charge distribution in FECA-induced droplets, electronegativity of the droplet with respect to those of reactive nanowire vapor species, growth temperature, and chamber pressure play important role in the VLS growth. On the basis of an in-depth analysis of various issues, a simple, novel, malleable (SNM) model has been presented for the VLS mechanism. The model appears to explain the formation and observed characteristics of a wide variety of nanowires, including elemental and compound semiconductor nanowires. Also it provides an understanding of the influence of the dynamic behavior of the droplets on the NW growth. This study finds that increase in diameter with time of the droplet of tapered nanowires results primarily from gradual incorporation of oversupplied nanowire species into the FECA-mediated droplet, which is supported by experiments. It finds also that optimum compositions of the droplet constituents are crucial for VLS nanowire growth. An approximate model presented to exemplify the parametric dependency of VLS growth provides good description of NW growth rate as a function of temperature. PMID:18380484

  10. Adapting SAFT-? perturbation theory to site-based molecular dynamics simulation. II. Confined fluids and vapor-liquid interfaces

    SciTech Connect

    Ghobadi, Ahmadreza F.; Elliott, J. Richard

    2014-07-14

    In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-? WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-? refers to the particular form of “statistical associating fluid theory” that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH{sub 2} and CH{sub 3} and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ?2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ?1% from simulation data while the theory reproduces the excess accumulation of ethane at the interface.

  11. Peptide Labeling Using Isobaric Tagging Reagents for Quantitative Phosphoproteomics.

    PubMed

    Cheng, Lei; Pisitkun, Trairak; Knepper, Mark A; Hoffert, Jason D

    2016-01-01

    Isobaric tagging reagents have become an invaluable tool for multiplexed quantitative proteomic analysis. These reagents can label multiple, distinct peptide samples from virtually any source material (e.g., tissue, cell line, purified proteins), allowing users the opportunity to assess changes in peptide abundances across many different time points or experimental conditions. Here, we describe the application of isobaric peptide labeling, specifically 8plex isobaric tags for relative and absolute quantitation (8plex iTRAQ), for quantitative phosphoproteomic analysis of cultured cells or tissue suspensions. For this particular protocol, labeled samples are pooled, fractionated by strong cation exchange chromatography, enriched for phosphopeptides, and analyzed by tandem mass spectrometry (LC-MS/MS) for both peptide identification and quantitation. PMID:26584918

  12. Prediction of fluid phase equilibrium of ternary mixtures in the critical region and the modified Leung-Griffiths theory

    NASA Astrophysics Data System (ADS)

    Lynch, John J.; Rainwater, James C.; van Poolen, Lambert J.; Smith, Duane H.

    1992-02-01

    The modified Leung-Griffiths theory of vapor-liquid equilibrium (VLE) is generalized to the case of three components. The principle of 'corresponding states' is reconsidered along with certain functions of 'field variables' within the model. The mathematical form of the coexistence boundary in terms of the field variables remains practically unchanged and conforms to modern scaling theory. The new model essentially predicts ternary fluid mixture phase boundaries in the critical region from previous vapor-liquid equilibrium data correlations of the three binary fluid mixture limits. Predicted saturation isotherms of the ethane + n-butane + n-pentane and ethane + n-butane + n-heptane mixtures are compared with experimental ternary VLE data in the literature.

  13. Nanoholes Formed by Au Particles Digging into GaAs and InP Substrates by Reverse Vapor-Liquid-Solid Mechanism

    NASA Astrophysics Data System (ADS)

    Tateno, Kouta; Gotoh, Hideki; Nakano, Hidetoshi

    2005-12-01

    Under a CBr4 gas supply, Au nanoparticles dig into GaAs and InP substrates to form nanoholes through the reverse vapor-liquid-solid mechanism. The nanohole formation tends to proceed in the [111]B direction. For GaAs, straight holes sometimes appear in the [011] and [211]B directions. This is due to the stable \\{111\\}B facets, which block the etching. For InP, many straight holes are seen in the [111]B direction. For both materials, direct etching of the surface also occurs. It is therefore necessary to find the optimum etching conditions for high selectivity to fabricate nanoholes.

  14. Removal of the samarium isobaric interference from promethium mass analysis

    SciTech Connect

    Shaw, R.W.; Young, J.P.; Smith, D.H.

    1988-02-01

    Resonance ionization mass spectroscopy (RIMS) is used to eliminate isobaric interference when determining the isotopic abundances of an element. In this application, RIMS is applied to the determination of promethium with the removal of samarium interference. In particular, promethium-147 is separated form samarium-147 and samarium-152.

  15. Decay Properties Of The Dipole Isobaric Analog Resonances

    E-print Network

    M. L. Gorelik; I. V. Safonov; M. H. Urin

    2006-12-06

    A continuum-RPA-based approach is applied to describe the decay properties of isolated dipole isobaric analog resonances in nuclei having not-too-large neutron excess. Calculated for a few resonances in 90Zr the elastic E1-radiative width and partial proton widths for decay into one-hole states of 89Y are compared with available experimental data.

  16. Controlling Axial p-n Heterojunction Abruptness Through Catalyst Alloying in Vapor-Liquid-Solid Grown Semiconductor Nanowires

    SciTech Connect

    Perea, Daniel E.; Schreiber, Daniel K.; Devaraj, Arun; Thevuthasan, Suntharampillai; Yoo, Jinkyoung; Dayeh, Shadi A.; Picraux, Samuel T.

    2012-07-30

    The p-n junction can be regarded as the most important electronic structure that is responsible for the ubiquity of semiconductor microelectronics today. Efforts to continually scale down the size of electronic components is guiding research to explore the use of nanomaterials synthesized from a bottom-up approach - group-IV semiconductor nanowires being one such material. However, Au-catalyzed synthesis of Si/Si1-x-Gex semiconductor nanowire heterojunctions using the commonly-used vapor-liquid-solid (VLS) growth technique results in diffuse heterojunction interfaces [1], leading to doubts of producing compositionally-sharp p-n junctions using this approach. However, we have recently reported the ability to increase Ge-Si nanowire heterojunction abruptness by VLS synthesis from a Au(1-x)Ga(x) catalyst alloy as shown by EDX analysis in an SEM [2]. In this work, we have extended the use of a AuGa catalyst alloy to produce more compositionally abrupt p-n junction interfaces compared to using pure Au as directly measured by atom probe tomography. As shown in Figure 1(a-b), individual Ge-Si heterostructured nanowires were grown vertically atop Ge(111) microposts. Direct growth on the microposts provides a facile approach to nanowire analysis which circumvents the need to use FIB-based sample preparation techniques. Both nanowires grown from pure Au and a AuGa catalyst alloy were analyzed. The corresponding 3D APT reconstruction of an individual heterostructured nanowire is shown in Figure 1(c) with the corresponding materials labeled. A 1-dimensional composition profile along the analysis direction in Figure 1(d) confirms an increase in heterojunction abruptness for nanowires grown from AuGa (~10nm) compared to nanowires grown from pure Au (~65nm). Analysis of the P distribution within the Si region (Figure 1(e)) indicates that P reaches a constant distribution over approximately 10nm when incorporated through the AuGa catalyst, whereas it continually increases over 100’s of nanometers when incorporated through pure Au. The apparent lower overall P concentration within the nanowire grown from the AuGa alloy suggests that the solubility of P in the alloy is lower compared to pure Au. The ability to controllably increase nanowire p-n junction abruptness is important for nanowire applications as solar cells and tunneling field effect transistors where an increase in device performance is expected from shaper p-n junction interfaces. [1] T.E. Clark et al., Nano Lett. 8 (2008) 1246. [2] D.E. Perea et al., Nano Lett. 11 (2011) 3117. [3] The research was supported through the user program at both the Center for Integrated Nanotechnologies at Los Alamos National Laboratory and the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory.

  17. Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H sub 2 O and NaCl-H sub 2 O

    SciTech Connect

    Hovey, J.K.; Pitzer, K.S.; Tanger, J.C. IV ); Bischoff, J.L.; Rosenbauer, R.J. )

    1990-02-08

    Measurements of isothermal vapor-liquid compositions for KCl-H{sub 2}O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H{sub 2}O, has been used for representation of the KCl-H{sub 2}O system from 300 to 410{degree}C. Improve parameters are also reported for NaCl-H{sub 2}O from 300 to 500{degree}C.

  18. Vapor-liquid phase equilibria of potassium chloride-water mixtures: Equation-of-state representation for KCl-H2O and NaCl-H2O

    USGS Publications Warehouse

    Hovey, J.K.; Pitzer, Kenneth S.; Tanger, J.C., IV; Bischoff, J.L.; Rosenbauer, R.J.

    1990-01-01

    Measurements of isothermal vapor-liquid compositions for KCl-H2O as a function of pressure are reported. An equation of state, which was originally proposed by Pitzer and was improved and used by Tanger and Pitzer to fit the vapor-liquid coexistence surface for NaCl-H2O, has been used for representation of the KCl-H2O system from 300 to 410??C. Improved parameters are also reported for NaCl-H2O from 300 to 500??C. ?? 1990 American Chemical Society.

  19. Phase equilibrium measurements on twelve binary mixtures

    SciTech Connect

    Giles, N.F.; Wilson, H.L.; Wilding, W.V.

    1996-11-01

    Phase equilibrium measurements have been performed on twelve binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following binary systems at two temperatures each: ethanethiol + propylene; nitrobenzene + methanol; pyridine + ethyl acetate; octane + tert-amyl methyl ether; diisopropyl ether + butane; 1,3-dichloro-2-propanol + epichlorohydrin; 2,3-dichloro-1-propanol + epichlorohydrin; 2,3-epoxy-1-propanol + epichlorohydrin; 3-chloro-1,2-propanediol + epichlorohydrin; methanol + hydrogen cyanide. For these systems, equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson, NRTL, or Redlich-Kister activity coefficient model to represent the liquid phase. The infinite dilution activity coefficient of methylamine in N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone was determined at three temperatures by performing PTx measurements on the N-methyl-2-pyrrolidone-rich half of the binary. Liquid-liquid equilibrium studies were made on the triethylene glycol + 1-pentene system at two temperatures by directly analyzing samples taken from each liquid phase.

  20. Isobaric yield ratio difference and Shannon information entropy

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Wei, Hui-Ling; Wang, Shan-Shan; Ma, Yu-Gang; Wada, Ryoichi; Zhang, Yan-Li

    2015-03-01

    The Shannon information entropy theory is used to explain the recently proposed isobaric yield ratio difference (IBD) probe which aims to determine the nuclear symmetry energy. Theoretically, the difference between the Shannon uncertainties carried by isobars in two different reactions (?In21), is found to be equivalent to the difference between the chemical potentials of protons and neutrons of the reactions [the IBD probe, IB- ?(??)21, with ? the reverse temperature]. From the viewpoints of Shannon information entropy, the physical meaning of the above chemical potential difference is interpreted by ?In21 as denoting the nuclear symmetry energy or density difference between neutrons and protons in reactions more concisely than from the statistical ablation-abrasion model.

  1. Vapor-liquid Equilibria and Polarization Behavior of the GCP Water Model: Gaussian Charge-on-spring versus Dipole Self-consistent Field approaches to induced polarization

    SciTech Connect

    Chialvo, Ariel A; Moucka, Filip; Vlcek, Lukas; Nezbeda, Ivo

    2015-01-01

    We implemented the Gaussian charge-on-spring (GCOS) version of the original self-consistent field implementation of the Gaussian Charge Polarizable water model and test its accuracy to represent the polarization behavior of the original model involving smeared charges and induced dipole moments. For that purpose we adapted the recently developed multiple-particle-move (MPM) within the Gibbs and isochoric-isothermal ensembles Monte Carlo methods for the efficient simulation of polarizable fluids. We assessed the accuracy of the GCOS representation by a direct comparison of the resulting vapor-liquid phase envelope, microstructure, and relevant microscopic descriptors of water polarization along the orthobaric curve against the corresponding quantities from the actual GCP water model.

  2. Remote sensing of atmospheric water vapor, liquid water, and wind speed at the ocean surface by passive microwave techniques from the Nimbus 5 satellite

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Wilheit, T. T.

    1979-01-01

    The microwave brightness temperature measurements for Nimbus 5 electrically scanned microwave radiometer (ESMR) and Nimbus-E microwave spectrometer (NEMS) are used to retrieve the atmospheric water vapor, liquid water, and wind speed by a quasi-statistical retrieval technique. It is shown that the brightness temperature can be utilized to yield these parameters under various weather conditions. Observations at 19.35, 22.235, and 31.4 GHz were input to the regression equations. The retrieved values of these parameters for portions of two Nimbus 5 orbits are presented. Then comparison between the retrieved parameters and the available observations on the total water vapor content and the surface wind speed are made.

  3. Remote sensing of atmospheric water vapor, liquid water and wind speed at the ocean surface by passive microwave techniques from the Nimbus-5 satellite

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Wilheit, T. T.

    1977-01-01

    The microwave brightness temperature measurements for Nimbus-5 electrically scanned microwave radiometer and Nimbus E microwave spectrometer are used to retrieve the atmospheric water vapor, liquid water and wind speed by a quasi-statistical retrieval technique. It is shown that the brightness temperature can be utilized to yield these parameters under various weather conditions. Observations at 19.35 GHz, 22.235 GHz and 31.4 GHz were input to the regression equations. The retrieved values of these parameters for portions of two Nimbus-5 orbits are presented. Then comparison between the retrieved parameters and the available observations on the total water vapor content and the surface wind speed are made. The estimated errors for retrieval are approximately 0.15 g/sq cm for water vapor content, 6.5 mg/sq cm for liquid water content and 6.6 m/sec for surface wind speed.

  4. Isotopic Ratio, Isotonic Ratio, Isobaric Ratio and Shannon Information Uncertainty

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Wei, Hui-Ling

    2014-11-01

    The isoscaling and the isobaric yield ratio difference (IBD) probes, both of which are constructed by yield ratio of fragment, provide cancelation of parameters. The information entropy theory is introduced to explain the physical meaning of the isoscaling and IBD probes. The similarity between the isoscaling and IBD results is found, i.e., the information uncertainty determined by the IBD method equals to ? - ? determined by the isoscaling (? (?) is the parameter fitted from the isotopic (isotonic) yield ratio).

  5. Reference pressure changes and available potential energy in isobaric coordinates

    NASA Technical Reports Server (NTRS)

    Robertson, F. R.

    1985-01-01

    A formulation of the available potential energy (APE) equation in isobaric coordinates which alleviates the need for computing temporal derivatives of reference pressure and describes how work done relates to changes in the APE of a limited region is presented. The APE budget equation possesses terms analogous to those in Johnson's (1970) isentropic version. It is shown that APE changes result from either mechanical work inside the domain or an exchange of energy via boundary processes with the surrounding environment.

  6. Isobar configurations: ?N correlations versus the independent particle model

    NASA Astrophysics Data System (ADS)

    Glavanakov, I. V.; Tabachenko, A. N.

    2015-05-01

    We present a comparative analysis of two models for the A (?, ?N) B reaction, which take into account the isobar configurations in the ground state of the nuclei: the ?N correlation model and the quasifree pion photoproduction model. The considered models differ in their descriptions of the nucleus states. The ?N correlation model takes into account the dynamic correlations of the nucleon and isobar formed in the virtual transition NN ? ?N, and in the quasifree pion photoproduction model, isobars and nucleons in the nucleus are considered as independent constituents. The predictions of the models are considered for two reactions 16O (?, ?+ p)15C and 16O (?, ?- p)15O. It is shown, that the two models predict the differential cross section significantly differing both in absolute values, and in the shape of the angular dependence. We compare the results of the ?N correlation model for the (?, ?N) and (?, ?NN) reactions with the 16O (?, ?- p) reaction data measured at BNL. Our results give support to the ?N correlation model.

  7. Toward an understanding of the salting-out effects in aqueous ionic liquid solutions: vapor-liquid equilibria, liquid-liquid equilibria, volumetric, compressibility, and conductivity behavior.

    PubMed

    Sadeghi, Rahmat; Mostafa, Bahar; Parsi, Elham; Shahebrahimi, Yasaman

    2010-12-16

    The action of particular electrolytes in altering the solution properties of ionic liquids is well documented, although the origin of this effect is not clearly defined. In order to clarify this point, the aim of this work is to obtain further evidence about the salting-out effect produced by the addition of different salts to aqueous solutions of water miscible ionic liquids by evaluating the effect of a large series of salts on the vapor-liquid equilibria, liquid-liquid phase diagram, volumetric, compressibility, and conductometric properties of ionic liquids 1-alkyl-3-methylimidazolium halide ([C(n)mim][X]). In the first part of this work, the experimental measurements of water activity at 298.15 and 308.15 K for aqueous binary and ternary solutions containing 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = butyl (C(4)), heptyl (C(7)), and octyl (C(8))), sodium dihydrogen citrate (NaH(2)Cit), disodium hydrogen citrate (Na(2)HCit), and trisodium citrate (Na(3)Cit) are taken using both vapor pressure osmometry (VPO) and improved isopiestic methods. The effect of temperature, charge on the anion of sodium citrate salts, and alkyl chain length of ionic liquids on the vapor-liquid equilibria properties of the investigated systems are studied. The constant water activity lines of all the ternary systems show large negative deviation from the linear isopiestic relation (Zdanovskii-Stokes-Robinson rule) derived using the semi-ideal hydration model, and the vapor pressure depression for a ternary solution is much larger than the sum of those for the corresponding binary solutions with the same molality of the ternary solution. The results have been interpreted in terms of the solute-water and solute-solute interactions. In the second part of this work, the effects of the addition of (NH(4))(3)Cit, K(3)Cit, Na(3)Cit, (NH(4))(2)HPO(4), and (NH(4))(3)PO(4) on the liquid-liquid phase diagram, apparent molar volume, isentropic compressibility, and conductivity of aqueous solutions containing the model ionic liquid 1-butyl-3-methylimidazolium iodide, [C(4)mim][I], are investigated at different temperatures. It was found that there is a relation between the relative concentration of various salts to form two-phase systems with [C(4)mim][I] and apparent molar volume or isentropic compressibility of transfer of [C(4)mim][I] from water to aqueous solutions of the investigated salts. PMID:21080679

  8. Vapor-liquid equilibria for nitric acid-water and plutonium nitrate-nitric acid-water solutions

    SciTech Connect

    Maimoni, A.

    1980-01-01

    The liquid-vapor equilibrium data for nitric acid and nitric acid-plutnonium nitrate-water solutions were examined to develop correlations covering the range of conditions encountered in nuclear fuel reprocessing. The scanty available data for plutonium nitrate solutions are of poor quality but allow an order of magnitude estimate to be made. A formal thermodynamic analysis was attempted initially but was not successful due to the poor quality of the data as well as the complex chemical equilibria involved in the nitric acid and in the plutonium nitrate solutions. Thus, while there was no difficulty in correlating activity coefficients for nitric acid solutions over relatively narrow temperature ranges, attempts to extend the correlations over the range 25/sup 0/C to the boiling point were not successful. The available data were then analyzed using empirical correlations from which normal boiling points and relative volatilities can be obtained over the concentration ranges 0 to 700 g/l Pu, 0 to 13 M nitric acid. Activity coefficients are required, however, if estimates of individual component vapor pressures are needed. The required ternary activity coefficients can be approximated from the correlations.

  9. An objective isobaric/isentropic technique for upper air analysis

    NASA Technical Reports Server (NTRS)

    Mancuso, R. L.; Endlich, R. M.; Ehernberger, L. J.

    1981-01-01

    An objective meteorological analysis technique is presented whereby both horizontal and vertical upper air analyses are performed. The process used to interpolate grid-point values from the upper-air station data is the same as for grid points on both an isobaric surface and a vertical cross-sectional plane. The nearby data surrounding each grid point are used in the interpolation by means of an anisotropic weighting scheme, which is described. The interpolation for a grid-point potential temperature is performed isobarically; whereas wind, mixing-ratio, and pressure height values are interpolated from data that lie on the isentropic surface that passes through the grid point. Two versions (A and B) of the technique are evaluated by qualitatively comparing computer analyses with subjective handdrawn analyses. The objective products of version A generally have fair correspondence with the subjective analyses and with the station data, and depicted the structure of the upper fronts, tropopauses, and jet streams fairly well. The version B objective products correspond more closely to the subjective analyses, and show the same strong gradients across the upper front with only minor smoothing.

  10. The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C

    USGS Publications Warehouse

    Bischoff, James L.; Rosenbauer, Robert J.; Fournier, Robert O.

    1996-01-01

    We determined vapor-liquid relations (P-T-x) and derived critical parameters for the system CaCl2-H2O from 380-500??C. Results show that the two-phase region of this system is extremely large and occupies a significant portion of the P-T space to which circulation of fluids in the Earth's crust is constrained. Results also show the system generates significant amounts of HCl (as much as 0.1 mol/kg) in the vapor phase buffered by the liquid at surprisingly high pressures (???230 bars at 380??C, <580 bars at 500??C), presumably by hydrolysis of CaCl2: CaCl2 + 2H2O = Ca(OH)2 + 2HCl. We interpret the abundance of HCl in the vapor as due to its preference for the vapor phase, and by the preference of Ca(OH)2 for either the liquid phase or solid. The recent recognition of the abundance of CaCl2 in deep brines of the Earth's crust and their hydrothermal mobilization makes the hydrolysis of CaCl2 geologically important. The boiling of Ca-rich brines produces abundant HCl buffered by the presence of the liquid at moderate pressures. The resultant Ca(OH)2 generated by this process reacts with silicates to form a variety of alteration products, such as epidote, whereas the vapor produces acid-alteration of rocks through which it ascends.

  11. Effects of transport gradients in a chemical vapor deposition reactor employing vapor-liquid-solid growth of ternary chalcogenide phase-change materials.

    PubMed

    Johnson, Derek C; Morris, Wesley D; Prieto, Amy L

    2010-04-23

    Chemical vapor deposition (CVD) with vapor-liquid-solid (VLS) growth is employed to synthesize individual Ge(2)Sb(2)Te(5) nanowires with the ultimate goal of synthesizing a large scale nanowire array for universal memory storage. A consistent challenge encountered during the synthesis is a lack of control over the composition and morphology across the growth substrate. To better understand the challenges associated with the CVD synthesis of the ternary chalcogenide, computational fluid dynamics simulations are performed to quantify 3D thermal and momentum transients in the growth conditions. While these gradients are qualitatively known to exist, they have not been adequately quantified in both the axial and radial directions when under pressure and flow conditions indicative of VLS growth. These data are not easily acquired by conventional means for the axial direction under vacuum and are a considerable challenge to accurately measure radially. The simulation data shown here provide 3D insights into the gradients which ultimately dictate the region of controllable stoichiometry and morphology. These results help explain the observed inhomogeneity of the characterized ternary chalcogenide growth products at various growth substrate locations. PMID:20351405

  12. Investigation of crystallinity and planar defects in the Si nanowires grown by vapor–liquid–solid mode using indium catalyst for solar cell applications

    NASA Astrophysics Data System (ADS)

    Ajmal Khan, Muhammad; Ishikawa, Yasuaki; Kita, Ippei; Tani, Ayumi; Yano, Hiroshi; Fuyuki, Takashi; Konagai, Makoto

    2016-01-01

    Stacking-fault-free and planar defect (twinning plane)-free In-catalyzed Si nanowires (NWs) are essential for carrier transport and nanoscale device applications. In this article, In-catalyzed, vertically aligned, and cone-shaped Si NWs on Si(111) were grown successfully, in the vapor–liquid–solid (VLS) mode. In particular, the influences of substrate temperature (TS) and cooling rate (?TS/?t) on the formation of planar defects, twinning planes along the [112] direction, and stacking faults in Si NWs were investigated. When TS was decreased from 600 °C to room temperature at a rate of 100 °C/240 s after Si NW growth, twinning plane defects perpendicular to the substrate and along different segments of (111)-oriented Si NWs were observed. Finally, one simple model was proposed to explain the stacking fault formation as well as Si NW length limitation due to the In-nanoparticle (In-NP) migration, and root causes of the twinning plane defects in the Si-NWs.

  13. Interface pn junction arrays with high yielded grown p-Si microneedles by vapor-liquid-solid method at low temperature

    NASA Astrophysics Data System (ADS)

    Islam, Md. Shofiqul; Ishida, Makoto

    2015-01-01

    In this work we report the fabrication and investigation of the properties of interface pn junction arrays formed at the interface of vertically aligned p-Si microneedles and n-Si substrate. Arrays of boron doped p-Si microneedles were grown on n-Si substrate with the maximum yield of 100% by Au-catalysed vapor-liquid-solid (VLS) growth using in-situ doping with the mixed gas of Si2H6 and B2H6 at temperature less than 700 °C, which is low as compared to the temperature (1100 °C) required by diffusion process to dope Si microneedles after VLS growth. The physical dimension (diameter, length) and position of these p-Si microneedles can be controlled. The variation of growth rate, diameter, conductivity, impurity concentration and hole mobility of these p-Si microneeedles were investigated with the variation of boron doping. The pn junctions, formed with p-Si microneedles having different diameters, were found to exhibit standard diode characteristics. These pn junction embedded Si microneedle arrays might be potential candidate in sensor area applications. Again, low temperature processing would be compatible to integrate these junction arrays with other circuitry on a chip. This work provides one step forward to realize more sophisticated vertical active devices (BJT, MOSFET, etc) with Si microneedles.

  14. Growth mechanism of metal-oxide nanowires synthesized by electron beam evaporation: a self-catalytic vapor-liquid-solid process.

    PubMed

    Yu, Hak Ki; Lee, Jong-Lam

    2014-01-01

    We report the growth mechanism of metal oxide nanostructures synthesized by electron beam evaporation. The condensed electron beam can easily decompose metal oxide sources that have a high melting point, thereby creating a self-catalytic metal nanodot for the vapor-liquid-solid process. The metal oxide nanostructures can be grown at a temperature just above the melting point of the self-catalyst by dissolving oxygen. The morphology of nanostructures, such as density and uniformity, strongly depends on the surface energy and surface migration energy of the substrate. The density of the self-catalytic metal nanodots increased with decreasing surface energies of the substrate due to the perfect wetting phenomenon of the catalytic materials on the high surface energy substrate. However, the surfaces with extremely low surface energy had difficulty producing the high density of self-catalyst nanodot, due to positive line tension, which increases the contact angle to >180°. Moreover, substrates with low surface migration energy, such as single layer graphene, make nanodots agglomerate to produce a less-uniform distribution compared to those produced on multi-layer graphene with high surface migration energy. PMID:25300518

  15. Growth mechanism of metal-oxide nanowires synthesized by electron beam evaporation: A self-catalytic vapor-liquid-solid process

    NASA Astrophysics Data System (ADS)

    Yu, Hak Ki; Lee, Jong-Lam

    2014-10-01

    We report the growth mechanism of metal oxide nanostructures synthesized by electron beam evaporation. The condensed electron beam can easily decompose metal oxide sources that have a high melting point, thereby creating a self-catalytic metal nanodot for the vapor-liquid-solid process. The metal oxide nanostructures can be grown at a temperature just above the melting point of the self-catalyst by dissolving oxygen. The morphology of nanostructures, such as density and uniformity, strongly depends on the surface energy and surface migration energy of the substrate. The density of the self-catalytic metal nanodots increased with decreasing surface energies of the substrate due to the perfect wetting phenomenon of the catalytic materials on the high surface energy substrate. However, the surfaces with extremely low surface energy had difficulty producing the high density of self-catalyst nanodot, due to positive line tension, which increases the contact angle to >180°. Moreover, substrates with low surface migration energy, such as single layer graphene, make nanodots agglomerate to produce a less-uniform distribution compared to those produced on multi-layer graphene with high surface migration energy.

  16. In situ magnetic field-assisted low temperature atmospheric growth of GaN nanowires via the vapor-liquid-solid mechanism.

    PubMed

    Kim, Jun Sik; Mohanty, Bhaskar Chandra; Han, Chan Su; Han, Seung Jun; Ha, Gwang Heon; Lin, Liwei; Cho, Yong Soo

    2014-01-01

    We report the growth of GaN nanowires at a low temperature of 750 °C and at atmospheric pressure in a conventional chemical vapor deposition (CVD) setup via the vapor-liquid-solid mechanism with remarkable control of directionality and growth behavior by using an in situ magnetic field. Under typical growth conditions, without any magnetic field, the nanowires are severely twisted and kinked, and exhibit a high density of planar stacking defects. With increasing in situ magnetic field strength, the microstructural defects are found to decrease progressively, and quasi-aligned nanowires are produced. At an applied magnetic field strength of 0.80 T, near-vertical aligned straight and several micrometers long nanowires of average diameter of ~40 nm with defect-free microstructure are routinely produced. Photoluminescence measurements show that the relative intensity of the defect-related peaks in the visible region with respect to the near-band-edge emission continuously decrease with increase in the applied in situ magnetic field strength, ascribable to the magnetic field-assisted significant structural improvement of the wires. It is found out that the degree of agglomerative Ni droplet on Si is critically influenced by the surface tension driven by the magnetic force, which in turn determines the eventual properties of the nanowires. PMID:24117213

  17. Effects of transport gradients in a chemical vapor deposition reactor employing vapor-liquid-solid growth of ternary chalcogenide phase-change materials

    NASA Astrophysics Data System (ADS)

    Johnson, Derek C.; Morris, Wesley D.; Prieto, Amy L.

    2010-04-01

    Chemical vapor deposition (CVD) with vapor-liquid-solid (VLS) growth is employed to synthesize individual Ge2Sb2Te5 nanowires with the ultimate goal of synthesizing a large scale nanowire array for universal memory storage. A consistent challenge encountered during the synthesis is a lack of control over the composition and morphology across the growth substrate. To better understand the challenges associated with the CVD synthesis of the ternary chalcogenide, computational fluid dynamics simulations are performed to quantify 3D thermal and momentum transients in the growth conditions. While these gradients are qualitatively known to exist, they have not been adequately quantified in both the axial and radial directions when under pressure and flow conditions indicative of VLS growth. These data are not easily acquired by conventional means for the axial direction under vacuum and are a considerable challenge to accurately measure radially. The simulation data shown here provide 3D insights into the gradients which ultimately dictate the region of controllable stoichiometry and morphology. These results help explain the observed inhomogeneity of the characterized ternary chalcogenide growth products at various growth substrate locations.

  18. Nested sampling of isobaric phase space for the direct evaluation of the isothermal-isobaric partition function of atomic systems

    NASA Astrophysics Data System (ADS)

    Wilson, Blake A.; Gelb, Lev D.; Nielsen, Steven O.

    2015-10-01

    Nested Sampling (NS) is a powerful athermal statistical mechanical sampling technique that directly calculates the partition function, and hence gives access to all thermodynamic quantities in absolute terms, including absolute free energies and absolute entropies. NS has been used predominately to compute the canonical (NVT) partition function. Although NS has recently been used to obtain the isothermal-isobaric (NPT) partition function of the hard sphere model, a general approach to the computation of the NPT partition function has yet to be developed. Here, we describe an isobaric NS (IBNS) method which allows for the computation of the NPT partition function of any atomic system. We demonstrate IBNS on two finite Lennard-Jones systems and confirm the results through comparison to parallel tempering Monte Carlo. Temperature-entropy plots are constructed as well as a simple pressure-temperature phase diagram for each system. We further demonstrate IBNS by computing part of the pressure-temperature phase diagram of a Lennard-Jones system under periodic boundary conditions.

  19. Photoproduction of the $?N$ pair on nuclei and isobar configurations

    E-print Network

    I. V. Glavanakov; A. N. Tabachenko

    2013-02-13

    A model of $\\pi N$ pair photoproduction on nuclei at high momentum transfer is presented. The $A(\\gamma,\\pi N)B$ reaction amplitude is obtained by means of an extended impulse approximation, according to which the nuclear wavefunction includes delta-isobar components in addition to nucleon components. A one-particle transition operator is defined in terms of the two-body $\\gamma N\\to\\pi N$ and $\\gamma \\Delta\\to\\pi N$ photoproduction amplitudes. Direct and exchange mechanisms of the nuclear photoproduction reaction are studied, and numerical estimates are made and presented of $^{12}{\\rm C}(\\gamma,\\pi^- p){^{11}{\\rm C}}$ and $^{12}{\\rm C}(\\gamma,\\pi^+ p){^{11}{\\rm Be}}$ differential cross sections at photon incident energies in the $\\Delta(1232)$ resonance region.

  20. The isobaric multiplet mass equation for A?71 revisited

    SciTech Connect

    Lam, Yi Hua; Blank, Bertram; Smirnova, Nadezda A.; Bueb, Jean Bernard; Antony, Maria Susai

    2013-11-15

    Accurate mass determination of short-lived nuclides by Penning-trap spectrometers and progress in the spectroscopy of proton-rich nuclei have triggered renewed interest in the isobaric multiplet mass equation (IMME). The energy levels of the members of T=1/2,1,3/2, and 2 multiplets and the coefficients of the IMME are tabulated for A?71. The new compilation is based on the most recent mass evaluation (AME2011) and it includes the experimental results on energies of the states evaluated up to end of 2011. Taking into account the error bars, a significant deviation from the quadratic form of the IMME for the A=9,35 quartets and the A=32 quintet is observed.

  1. Isobaric molecular dynamics simulations of hard sphere systems

    NASA Astrophysics Data System (ADS)

    Gruhn, T.; Monson, P. A.

    2001-06-01

    We describe an implementation of the Andersen algorithm for simulating the molecular dynamics in the isobaric isoenthalpic (NPH) ensemble for the hard sphere potential. The work is based on the adaptation of the Andersen algorithm to hard spheres by de Smedt et al. For a hard sphere system in the NPH ensemble, the particle velocities are not constant between collisions and we describe an efficient method for handling this part of the dynamics. The method is extended to give an NPT ensemble simulation of hard sphere systems by applying an ad hoc rescaling of the velocities. The accuracy of the algorithms is tested by comparison with traditional NVE simulation results for the structural, thermodynamic, and transport properties.

  2. Hard breakup of the deuteron into two {Delta} isobars

    SciTech Connect

    Granados, Carlos G.; Sargsian, Misak M.

    2011-05-15

    We study high-energy photodisintegration of the deuteron into two {Delta} isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn{yields}{Delta}{Delta} scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn{yields}{Delta}{Delta} scattering. We predict that the cross section of the deuteron breakup to {Delta}{sup ++}{Delta}{sup -} is 4-5 times larger than that of the breakup to the {Delta}{sup +}{Delta}{sup 0} channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard {Delta} isobars are the result of the disintegration of the preexisting {Delta}{Delta} components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both {Delta}{sup ++}{Delta}{sup -} and {Delta}{sup +}{Delta}{sup 0} channels to be similar.

  3. The non-Newtonian heat and mass transport of He 2 in porous media used for vapor-liquid phase separation. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.

    1985-01-01

    This investigation of vapor-liquid phase separation (VLPS) of He 2 is related to long-term storage of cryogenic liquid. The VLPS system utilizes porous plugs in order to generate thermomechanical (thermo-osmotic) force which in turn prevents liquid from flowing out of the cryo-vessel (e.g., Infrared Astronomical Satellite). An apparatus was built and VLPS data were collected for a 2 and a 10 micrometer sintered stainless steel plug and a 5 to 15 micrometer sintered bronze plug. The VLPS data obtained at high temperature were in the nonlinear turbulent regime. At low temperature, the Stokes regime was approached. A turbulent flow model was developed, which provides a phenomenological description of the VLPS data. According to the model, most of the phase separation data are in the turbulent regime. The model is based on concepts of the Gorter-Mellink transport involving the mutual friction known from the zero net mass flow (ZNMF) studies. The latter had to be modified to obtain agreement with the present experimental VLPS evidence. In contrast to the well-known ZNMF mode, the VLPS results require a geometry dependent constant (Gorter-Mellink constant). A theoretical interpretation of the phenomenological equation for the VLPS data obtained, is based on modelling of the dynamics of quantized vortices proposed by Vinen. In extending Vinen's model to the VLPS transport of He 2 in porous media, a correlation between the K*(GM) and K(p) was obtained which permits an interpretation of the present findings. As K(p) is crucial, various methods were introduced to measure the permeability of the porous media at low temperatures. Good agreement was found between the room temperature and the low temperature K(p)-value of the plugs.

  4. Finite-size scaling study of the vapor-liquid critical properties of confined fluids: Crossover from three dimensions to two dimensions.

    PubMed

    Liu, Yang; Panagiotopoulos, Athanassios Z; Debenedetti, Pablo G

    2010-04-14

    We perform histogram-reweighting grand canonical Monte Carlo simulations of the Lennard-Jones fluid confined between two parallel hard walls and determine the vapor-liquid critical and coexistence properties in the range of sigma

  5. Encoding abrupt and uniform dopant profiles in vapor-liquid-solid nanowires by suppressing the reservoir effect of the liquid catalyst.

    PubMed

    Christesen, Joseph D; Pinion, Christopher W; Zhang, Xing; McBride, James R; Cahoon, James F

    2014-11-25

    Semiconductor nanowires (NWs) are often synthesized by the vapor-liquid-solid (VLS) mechanism, a process in which a liquid droplet-supplied with precursors in the vapor phase-catalyzes the growth of a solid, crystalline NW. By changing the supply of precursors, the NW composition can be altered as it grows to create axial heterostructures, which are applicable to a range of technologies. The abruptness of the heterojunction is mediated by the liquid catalyst, which can act as a reservoir of material and impose a lower limit on the junction width. Here, we demonstrate that this "reservoir effect" is not a fundamental limitation and can be suppressed by selection of specific VLS reaction conditions. For Au-catalyzed Si NWs doped with P, we evaluate dopant profiles under a variety of synthetic conditions using a combination of elemental imaging with energy-dispersive X-ray spectroscopy and dopant-dependent wet-chemical etching. We observe a diameter-dependent reservoir effect under most conditions. However, at sufficiently slow NW growth rates (?250 nm/min) and low reactor pressures (?40 Torr), the dopant profiles are diameter independent and radially uniform with abrupt, sub-10 nm axial transitions. A kinetic model of NW doping, including the microscopic processes of (1) P incorporation into the liquid catalyst, (2) P evaporation from the catalyst, and (3) P crystallization in the Si NW, quantitatively explains the results and shows that suppression of the reservoir effect can be achieved when P evaporation is much faster than P crystallization. We expect similar reaction conditions can be developed for other NW systems and will facilitate the development of NW-based technologies that require uniform and abrupt heterostructures. PMID:25363730

  6. Measurement of vapor/liquid distributions in a binary-component fuel spray using laser imaging of droplet scattering and vapor absorption

    NASA Astrophysics Data System (ADS)

    Li, Shiyan; Zhang, Yuyin; Wu, Shenqi; Xu, Bin

    2014-08-01

    Fuel volatility has a great effect on its evaporation processes and the mixture formation and thus combustion and emissions formation processes in internal combustion engines. To date, however, instead of the actual gasoline or diesel fuel, many researchers have been using single-component fuel in their studies, because the composition of the former is too complicated to understand the real physics behind the evaporation and combustion characteristics. Several research groups have reported their results on droplets evaporation in a spray of multi-component fuel, carried out both numerically and experimentally. However, there are plenty of difficulties in quantitative determination of vapor concentration and droplet distributions of each component in a multicomponent fuel spray. In this study, to determine the vapor phase concentration and droplet distributions in an evaporating binary component fuel spray, a laser diagnostics based on laser extinction by droplet scattering and vapor absorption was developed. In practice, measurements of the vapor concentration distributions of the lower (n-tridencane) and higher (n-octane) volatility components in the binary component fuel sprays have been carried out at ambient temperatures of 473K and 573K, by substituting p-xylene for noctane or ?-methylnaphthalene for n-tridecane. p-Xylene and ?-methylnaphthalene were selected as the substitutes is because they have strong absorption band near 266nm and transparent near 532nm and, their thermo-physical properties are similar to those of the original component. As a demonstration experiment, vapor/liquid distribution of the lower boiling point (LBP) and higher boiling point (HBP) components in the binary component fuel spray have been obtained.

  7. Vapor-liquid-solid epitaxial growth of Si1-xGex alloy nanowires: Composition dependence on precursor reactivity and morphology control for vertical forests

    NASA Astrophysics Data System (ADS)

    Choi, S. G.; Manandhar, P.; Picraux, S. T.

    2015-07-01

    Growth of high-density group IV alloy nanowire forests is critical for exploiting their unique functionalities in many applications. Here, the compositional dependence on precursor reactivity and optimized conditions for vertical growth are studied for Si1-xGex alloy nanowires grown by the vapor-liquid-solid method. The nanowire composition versus gas partial-pressure ratio for germane-silane and germane-disilane precursor combinations is obtained at 350 °C over a wide composition range (0.05 ? x ? 0.98) and a generalized model to predict composition for alloy nanowires is developed based on the relative precursor partial pressures and reactivity ratio. In combination with germane, silane provides more precise compositional control at high Ge concentrations (x > 0.7), whereas disilane greatly increases the Si concentration for a given gas ratio and enables more precise alloy compositional control at small Ge concentrations (x < 0.3). Vertically oriented, non-kinking nanowire forest growth on Si (111) substrates is then discussed for silane/germane over a wide range of compositions, with temperature and precursor partial pressure optimized by monitoring the nanowire growth front using in-situ optical reflectance. For high Ge compositions (x ? 0.9), a "two-step" growth approach with nucleation at higher temperatures results in nanowires with high-density and uniform vertical orientation. With increasing Si content (x ? 0.8), the optimal growth window is shifted to higher temperatures, which minimizes nanowire kinking morphologies. For Si-rich Si1-xGex alloys (x ? 0.25), vertical nanowire growth is enhanced by single-step, higher-temperature growth at reduced pressures.

  8. Effect of polymorphism and dispersity on the crystal-melt phase equilibrium

    NASA Astrophysics Data System (ADS)

    Shablovskii, Ya. O.

    2010-08-01

    The laws of the effect of the dispersity of a polymorphic crystalline substance on the equilibrium with its melt are revealed. The size dependences of the molar volume of a polycrystalline substance, the isothermal-transformation pressure, and the isobaric-transformation temperature are obtained. The Ostwald stage law is analytically generalized to the case of solidification from a melt.

  9. Rotational-Vibrational Raman Spectroscopy for Measurements of Thermochemistry in Non-isobaric Environments 

    E-print Network

    Bayeh, Alexander C.

    2010-01-14

    laser probe, and are combined onto the same EMCCD detector. Combining the two techniques allows for a single-shot measurement of major species, pressure, and temperature in a turbulent non-isobaric environment that is chemically reacting. Temperature...

  10. Rapid Analysis of Isobaric Exogenous Metabolites by Differential Mobility Spectrometry Mass Spectrometry

    SciTech Connect

    Parson, Whitney B; Schneider, Bradley B; Kertesz, Vilmos; Corr, Jay; Covey, Thomas R.; Van Berkel, Gary J

    2011-01-01

    The direct separation of isobaric glucuronide metabolites from propranolol dosed tissue extracts by differential mobility spectrometry mass spectrometry (DMS-MS) with the use of a polar gas-phase chemical modifier was demonstrated. The DMS gas-phase separation was able to resolve the isobaric metabolites with separation times on the order of ms instead of mins to hrs typically required when using pre-ionization chromatographic separation methods. Direct separation of isobaric metabolites from the complex tissue extract was validated using standards as well as implementing an HPLC separation prior to the DMS-MS analysis to pre-separate the species of interest. The ability to separate isobaric exogenous metabolites directly from a complex tissue extract is expected to facilitate the drug development process by increasing analytical throughput without the requirement for pre-ionization cleanup or separation strategies.

  11. Thermodynamics of Si(OH)4 in the vapor phase of water: Henry’s and vapor-liquid distribution constants, fugacity and cross virial coefficients

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.

    2012-01-01

    The fugacity coefficients of Si(OH)4 are evaluated from solubilities of solid phases of SiO2 in the vapor phase of water. The virial equation of state, truncated at the third virial coefficient, is employed to describe the fugacity coefficients of Si(OH)4. The temperature dependencies of the second, B12, and the third, C112, cross virial coefficients for H2O-Si(OH)4 interactions are approximated by empirical relations. It is found that silica-water interactions in the vapor phase are significantly more non-ideal compared to water-water interactions. Knowledge of B12 and C112 allows calculation of solubilities of quartz (Q) and amorphous silica (AS) in steam up to the density of 200 kg m-3 in satisfactory agreement with available data, and should provide reasonable solubility values at temperatures where no experimental results exist. The calculated values of the solubility of Q and AS in saturated vapor up to the critical temperature of water, Tc, are tabulated. The partial molar properties of dilute solutes close to the critical point of water are governed by the Krichevskii parameter, the value of which for Si(OH)4 is evaluated from available data (mainly vapor-liquid distribution constants for silica) to be equal to -187 ± 10 MPa. The knowledge of the thermodynamic properties of Si(OH)4 in the ideal gas state and in the state of the standard solution in liquid water allows calculating Henry’s constant, kH, for Si(OH)4 up to 623.15 K at water saturation pressure P1?. The theoretically-based equation, containing the Krichevskii parameter, allows extrapolating kH values all the way toward the critical temperature of water. This, in turn, makes possible calculation of the solubility of quartz and amorphous silica in liquid water at P1? at all temperatures up to Tc. The presented results should be useful for modeling solid-liquid-vapor, solid-vapor and liquid-vapor equilibria in the H2O-SiO2 system at steam densities up to 200 kg m-3.

  12. Equilibrium distribution

    E-print Network

    Ashot Vagharshakyan

    2015-08-29

    In the paper discusses the interaction between two charged balls in equilibrium state. It is shown that, depending of the sizes, charges and distance, the balls can move in the same or opposite direction. They can repulse and attract. It is proved, that one of the balls may vibrate.

  13. Models of p- T diagrams for a ternary system with invariant equilibrium of three solid phases, liquid, and vapor

    NASA Astrophysics Data System (ADS)

    Khaldoyanidi, K. A.

    2013-03-01

    A version of a model of the p- T diagram for a ternary system in which three solid phases, liquid, and vapor are in invariant five-phase equilibrium is developed. The phase equilibria and phase transitions in the isobaric T- x- y diagram are analyzed, and isothermal and polythermal sections are presented.

  14. Equilibrium Onions?

    E-print Network

    L. Ramos; D. Roux; P. D. Olmsted; M. E. Cates

    2004-07-01

    We demonstrate the possibility of a stable equilibrium multi-lamellar (``onion'') phase in pure lamellar systems (no excess solvent) due to a sufficiently negative Gaussian curvature modulus. The onion phase is stabilized by non-linear elastic moduli coupled to a polydisperse size distribution (Apollonian packing) to allow space-filling without appreciable elastic distortion. This model is compared to experiments on copolymer-decorated lamellar surfactant systems, with reasonable qualitative agreement.

  15. 4C modeling of the supercritical helium loop HELIOS in isobaric configuration

    NASA Astrophysics Data System (ADS)

    Guelfi, F.; Bonifetto, R.; Hoa, C.; Savoldi, L.; Zanino, R.

    2014-11-01

    Superconducting magnets for tokamak fusion reactors are subject to highly variable loads due to the intrinsically pulsed operation of the machine. The refrigerator should, on the contrary, work under conditions as stable as possible and should be sized based on the averaged loads. In this paper, the cryogenic circuit module of the 4C (Cryogenic Circuit Conductor and Coil) code is used to analyze the isobaric configuration of the HELIOS (HElium Loop for hIgh lOads Smoothing) facility at CEA Grenoble, France. The 4C model is validated against experimental data from the isobaric HELIOS configuration: the computed evolution of temperature, pressure and mass flow rate at different circuit locations shows a good agreement with the measurements for two different pulsed heat load scenarios, with and without regulation. The advantages of the (somewhat more complicated) isobaric configuration vs. the isochoric configuration in terms of heat load smoothing are highlighted. 4C simulations are used to propose a new HELIOS layout with helium charging and discharging lines located in such a way that the HELIOS performance in the isobaric configuration is optimized. The paper confirms the importance of the isobaric configuration for a tokamak cryogenic circuit, as well as the accuracy of 4C in modeling the HELIOS operation, even in the presence of complex regulation.

  16. Liquid-vapor equilibrium in the systems hexane-benzene-petroleum sulfoxides-diethylene glycol and hexane-benzene-petroleum sulfoxides-dimethylformamide

    SciTech Connect

    Vakhitova, N.G.; Baikova, A.Y.; Murinov, Y.I.; Nikitin, Y.E.

    1985-12-01

    This paper reports the results of studies of liquid-vapor equilibrium in the benzene-hexane system in presence of binary extractants: petroleum sulfoxide-dimethylformamide (DMFA) and petroleum sulfoxide-diethylene glycol (DEG). The physicochemical properties of the extractants are presented and the influence of the content of slelective solvent on vapor-liquid equilibrium was studied; the total concentration of the binary solvent in the experiments was 50 vol. %. Results also show that the introduction of a second solvent into petroleum sulfoxides alters the vapor-liquid equilibrium in the system substantially. The volatility of hexane is increased considerably, especially in the case of the PSO-DMFA mixed extractant. In the case of benzene, petroleum sulfoxides and their mixtures with diethylene glycol and dimethylformamide are approximately equal in effectiveness in the region of low benzene concentrations. In the region of high benzene concentrations mixed extractants are more effective than petroleum sulfoxides; this is decisive for isolation of aromatic hydrocarbons from mixtures rich in aromatics.

  17. Vapor-liquid equilibria from the triple point up to the critical point for the new generation of TIP4P-like models: TIP4P/Ew, TIP4P/2005, and TIP4P/ice.

    PubMed

    Vega, C; Abascal, J L F; Nezbeda, I

    2006-07-21

    The vapor-liquid equilibria of three recently proposed water models have been computed using Gibbs-Duhem simulations. These models are TIP4P/Ew, TIP4P/2005, and TIP4P/ice and can be considered as modified versions of the TIP4P model. By design TIP4P reproduces the vaporization enthalpy of water at room temperature, whereas TIP4P/Ew and TIP4P/2005 match the temperature of maximum density and TIP4P/ice the melting temperature of water. Recently, the melting point for each of these models has been computed, making it possible for the first time to compute the complete vapor-liquid equilibria curve from the triple point to the critical point. From the coexistence results at high temperature, it is possible to estimate the critical properties of these models. None of them is capable of reproducing accurately the critical pressure or the vapor pressures and densities. Additionally, in the cases of TIP4P and TIP4P/ice the critical temperatures are too low and too high, respectively, compared to the experimental value. However, models accounting for the density maximum of water, such as TIP4P/Ew and TIP4P/2005 provide a better estimate of the critical temperature. In particular, TIP4P/2005 provides a critical temperature just 7 K below the experimental result as well as an extraordinarily good description of the liquid densities from the triple point to the critical point. All TIP4P-like models present a ratio of the triple point temperature to the critical point temperature of about 0.39, compared with the experimental value of 0.42. As is the case for any effective potential neglecting many body forces, TIP4P/2005 fails in describing simultaneously the vapor and the liquid phases of water. However, it can be considered as one of the best effective potentials of water for describing condensed phases, both liquid and solid. In fact, it provides a completely coherent view of the phase diagram of water including fluid-solid, solid-solid, and vapor-liquid equilibria. PMID:16863358

  18. Improved Thermometer from Intermediate Mass Fragments in Heavy-Ion Collisions with Isobaric Yield Ratio Difference

    E-print Network

    Ma, Chun-Wang; Qiao, Chun-Yuan; Cao, Xi-Guang

    2015-01-01

    \\item[Background] Temperature is an important parameter in studying many important questions in heavy-ion collisions. A thermometer based on the isobaric yield ratio (IYR) has been proposed [Ma \\textit{et al.}, Phys. Rev. C \\textbf{86}, 054611 (2012) and Ma \\textit{et al.}, \\textit{ibid.}, Phys. Rev. C \\textbf{88}, 014609 (2013)]. \\item[Purpose] An improved thermometer ($T_{IB}$) is proposed based on the difference between IYRs. $T_{IB}$ obtained from isobars in different reactions will be compared. \\item[Methods] The yields of three isobars are employed in $T_{IB}$. The residual free energy of the three isobars are replaced by that of the binding energy. No secondary decay modification for odd $A$ fragment is used in $T_{IB}$. \\item[Results] The measured fragment yields in the 140$A$ MeV $^{40, 48}$Ca + $^{9}$Be ($^{181}$Ta) and $^{58, 64}$Ni + $^9$Be ($^{181}$Ta), the 1$A$ GeV $^{124, 136}$Xe + Pb, and the $^{112,124}$Sn + $^{112,124}$Sn reactions have been analyzed to obtain $T_{IB}$ from IMFs. $T_{IB}$ fr...

  19. Formation of isobaric discontinuities in large-scale flute drift motions

    SciTech Connect

    Dreizin, Y.A.; Sokolov, E.P.

    1982-05-01

    The flute drift motion in MHD-stable plasma configurations with closed lines of force is analyzed qualitatively. The onset of this motion can lead to isobaric discontinuities in experimentally observable quantitites: the electric potential and the electron and ion densities and temperatures.

  20. High-Resolution Enabled 12-Plex DiLeu Isobaric Tags for Quantitative Proteomics

    PubMed Central

    2015-01-01

    Multiplex isobaric tags (e.g., tandem mass tags (TMT) and isobaric tags for relative and absolute quantification (iTRAQ)) are a valuable tool for high-throughput mass spectrometry based quantitative proteomics. We have developed our own multiplex isobaric tags, DiLeu, that feature quantitative performance on par with commercial offerings but can be readily synthesized in-house as a cost-effective alternative. In this work, we achieve a 3-fold increase in the multiplexing capacity of the DiLeu reagent without increasing structural complexity by exploiting mass defects that arise from selective incorporation of 13C, 15N, and 2H stable isotopes in the reporter group. The inclusion of eight new reporter isotopologues that differ in mass from the existing four reporters by intervals of 6 mDa yields a 12-plex isobaric set that preserves the synthetic simplicity and quantitative performance of the original implementation. We show that the new reporter variants can be baseline-resolved in high-resolution higher-energy C-trap dissociation (HCD) spectra, and we demonstrate accurate 12-plex quantitation of a DiLeu-labeled Saccharomyces cerevisiae lysate digest via high-resolution nano liquid chromatography–tandem mass spectrometry (nanoLC–MS2) analysis on an Orbitrap Elite mass spectrometer. PMID:25405479

  1. On the density of volume states in the isobaric ensemble Phil Attard

    E-print Network

    Attard, Phil

    NOTES On the density of volume states in the isobaric ensemble Phil Attard Department of Physics S kB dx x x ln x , 1 where (x) is the density of states, (x) is the probability of one particular state, and (x) (x) (x) is the probability density, i.e., x) dx is the probability of finding the system

  2. An rf-carpet electrospray ion source to provide isobaric mass calibrants for trans-uranium elements

    E-print Network

    S. Naimi; S. Nakamura; Y. Ito; H. Mita; K. Okada; A. Ozawa; P. Schury; T. Sonoda; A. Takamine; M. Wada; H. Wollnik

    2012-12-16

    For trans-uranium elements, stable atomic isobars do not exist. In order to provide isobaric reference ions for the mass measurement of trans-uranium elements, an electrospray ion source (ESI) was combined with an rf-carpet to collect molecular ions efficiently. The rf-carpet allows for simplification of the pumping system to transport ions from the ESI to a precision mass analyzer. Molecular ions appropriate for isobaric references of trans-uranium elements were extracted from the rf-carpet and analyzed by a multi-reflection time-of-flight mass spectrograph (MRTOF-MS) with a resolving power of $\\rm{R_m} \\gtrsim100,000$.

  3. Isobars of an ideal Bose gas within the grand canonical ensemble

    NASA Astrophysics Data System (ADS)

    Jeon, Imtak; Kim, Sang-Woo; Park, Jeong-Hyuck

    2011-08-01

    We investigate the isobar of an ideal Bose gas confined in a cubic box within the grand canonical ensemble for a large yet finite number of particles, N. After solving the equation of the spinodal curve, we derive precise formulas for the supercooling and the superheating temperatures that reveal an N-1/3 or N-1/4 power correction to the known Bose-Einstein condensation temperature in the thermodynamic limit. Numerical computations confirm the accuracy of our analytical approximation, and further show that the isobar zigzags on the temperature-volume plane if N?14393. In particular, for the Avogadro’s number of particles, the volume expands discretely about 105 times. Our results quantitatively agree with a previous study on the canonical ensemble within 0.1% error.

  4. Isobars of an ideal Bose gas within the grand canonical ensemble

    SciTech Connect

    Jeon, Imtak; Park, Jeong-Hyuck; Kim, Sang-Woo

    2011-08-15

    We investigate the isobar of an ideal Bose gas confined in a cubic box within the grand canonical ensemble for a large yet finite number of particles, N. After solving the equation of the spinodal curve, we derive precise formulas for the supercooling and the superheating temperatures that reveal an N{sup -1/3} or N{sup -1/4} power correction to the known Bose-Einstein condensation temperature in the thermodynamic limit. Numerical computations confirm the accuracy of our analytical approximation, and further show that the isobar zigzags on the temperature-volume plane if N{>=}14 393. In particular, for the Avogadro's number of particles, the volume expands discretely about 10{sup 5} times. Our results quantitatively agree with a previous study on the canonical ensemble within 0.1% error.

  5. Revalidation of the isobaric multiplet mass equation for the A =20 quintet

    NASA Astrophysics Data System (ADS)

    Glassman, B. E.; Pérez-Loureiro, D.; Wrede, C.; Allen, J.; Bardayan, D. W.; Bennett, M. B.; Brown, B. A.; Chipps, K. A.; Febbraro, M.; Fry, C.; Hall, M. R.; Hall, O.; Liddick, S. N.; O'Malley, P.; Ong, W.; Pain, S. D.; Schwartz, S. B.; Shidling, P.; Sims, H.; Thompson, P.; Zhang, H.

    2015-10-01

    An unexpected breakdown of the isobaric multiplet mass equation in the A =20 ,T =2 quintet was recently reported, presenting a challenge to modern theories of nuclear structure. In the present work, the excitation energy of the lowest T =2 state in 20Na has been measured to be 6498.4 ±0 .2stat±0 .4syst keV by using the superallowed 0+?0+ beta decay of 20Mg to access it and an array of high-purity germanium detectors to detect its ? -ray deexcitation. This value differs by 27 keV (1.9 standard deviations) from the recommended value of 6525 ±14 keV and is a factor of 28 more precise. The isobaric multiplet mass equation is shown to be revalidated when the new value is adopted.

  6. Revalidation of the isobaric multiplet mass equation for the $A=20$ quintet

    E-print Network

    Glassman, B E; Wrede, C; Allen, J; Bardayan, D W; Bennett, M B; Brown, B A; Chipps, K A; Febbraro, M; Fry, C; Hall, M R; Hall, O; Liddick, S N; O'Malley, P; Ong, W; Pain, S D; Schwartz, S B; Shidling, P; Sims, H; Thompson, P; Zhang, H

    2015-01-01

    An unexpected breakdown of the isobaric multiplet mass equation in the $A=20$, $T=2$ quintet was recently reported, presenting a challenge to modern theories of nuclear structure. In the present work, the excitation energy of the lowest $T = 2$ state in $^{20}$Na has been measured to be $6498.4 \\pm 0.2_{\\textrm{stat}} \\pm 0.4_{\\textrm{syst}}$ keV by using the superallowed $0^+ \\rightarrow 0^+$ beta decay of $^{20}$Mg to access it and an array of high-purity germanium detectors to detect its $\\gamma$-ray deexcitation. This value differs by 27 keV (1.9 standard deviations) from the recommended value of $6525 \\pm 14$ keV and is a factor of 28 more precise. The isobaric multiplet mass equation is shown to be revalidated when the new value is adopted.

  7. Revalidation of the isobaric multiplet mass equation for the $A=20$ quintet

    E-print Network

    B. E. Glassman; D. Pérez-Loureiro; C. Wrede; J. Allen; D. W. Bardayan; M. B. Bennett; B. A. Brown; K. A. Chipps; M. Febbraro; C. Fry; M. R. Hall; O. Hall; S. N. Liddick; P. O'Malley; W. Ong; S. D. Pain; S. B. Schwartz; P. Shidling; H. Sims; P. Thompson; H. Zhang

    2015-11-05

    An unexpected breakdown of the isobaric multiplet mass equation in the $A=20$, $T=2$ quintet was recently reported, presenting a challenge to modern theories of nuclear structure. In the present work, the excitation energy of the lowest $T = 2$ state in $^{20}$Na has been measured to be $6498.4 \\pm 0.2_{\\textrm{stat}} \\pm 0.4_{\\textrm{syst}}$ keV by using the superallowed $0^+ \\rightarrow 0^+$ beta decay of $^{20}$Mg to access it and an array of high-purity germanium detectors to detect its $\\gamma$-ray deexcitation. This value differs by 27 keV (1.9 standard deviations) from the recommended value of $6525 \\pm 14$ keV and is a factor of 28 more precise. The isobaric multiplet mass equation is shown to be revalidated when the new value is adopted.

  8. Densities, isobaric thermal expansion coefficients and isothermal compressibilities of linear alkylbenzene

    E-print Network

    Xiang Zhou; Qingmin Zhang; Qian Liu; Zhenyu Zhang; Yayun Ding; Li Zhou; Jun Cao

    2015-04-04

    We report the measurements of the densities of linear alkylbenzene at three temperatures over 4 to 23 Celsius degree with pressures up to 10 MPa. The measurements have been analysed to yield the isobaric thermal expansion coefficients and, so far for the first time, isothermal compressibilities of linear alkylbenzene. Relevance of results for current generation (i.e. Daya Bay) and next generation (i.e. JUNO) large liquid scintillator neutrino detectors are discussed.

  9. Resonance ionization mass spectrometric study of the promethium/samarium isobaric pair

    SciTech Connect

    Shaw, R.W.; Young, J.P.; Smith, D.H.

    1988-01-01

    Samarium daughters are problematic in isotope ratio measurements of promethium because they are isobaric. Resonance ionization mass spectrometry was utilized to circumvent this problem. An ionization selectivity factor of at least 1000:1 has been measured for promethium over samarium at 584.6 nm. Resonance ionization spectra have been recorded for both elements over the 528-560 and 580-614 nm wavelength ranges.

  10. Effect of epidural infusion of isobaric 2% lidocaine on spinal cord ganglionic neurons.

    PubMed

    Volchkov, V A; Boikova, N V; Zaitsev, A A; Strashnov, V I; Tomson, V V

    2002-12-01

    We analyzed morphological and histoenzymologic changes in spinal cord ganglionic neurons of mongrel dogs caused by epidural infusion of isobaric 2% lidocaine. Lidocaine produced no pathological structural and metabolic alterations in the nervous tissue. Both epidural infusion of 0.9% NaCl and lidocaine produced some morphofunctional rearrangements in spinal ganglionic neurons. These alterations were within the limits of physiological norm and probably attested to functional response of the examined nerve tissue structures to epidural infusion. PMID:12660844

  11. Resonant scattering of isobaric [sup 19]Ne and [sup 19]F beams on an H target

    SciTech Connect

    Coszach, R.; Delbar, T.; Galster, W.; Leleux, P.; Licot, I.; Lienard, E.; Lipnik, P.; Michotte, C.; Ninane, A.; Vervier, J. ); Bain, C.R.; Davinson, T.; Page, R.D.; Shotter, A.C.; Woods, P.J. ); Baye, D.; Binon, F.; Descouvemont, P.; Duhamel, P.; Vanhorenbeeck, J.; Vincke, M. ); Decrock, P.; Huyse, M.; Van Duppen, P.; Vancraeynest, G. ); Barker, F.C. )

    1994-09-01

    Resonances in [sup 20]Na above the proton threshold have been studied by scattering radioactive [sup 19]Ne beams off thick polyethylene targets. The isobaric [sup 19]F+[ital p] scattering was also examined. The analysis of the data under different theoretical approaches is discussed. The energy, total width, spin, and parity of two resonances in [sup 20]Na were assigned unambiguously. The results are compared to those obtained by indirect methods.

  12. Coupled-channel treatment of Isobaric Analog Resonances in (p,p') Capture Processes

    SciTech Connect

    Thompson, I J; Arbanas, Goran

    2013-01-01

    With the advent of nuclear reactions on unstable isotopes, there has been a renewed interest in using isobaric analogue resonances (IAR) as a tool for probing the nuclear structure. The position and width of isobaric analogue resonances in nucleon-nucleus scattering are accurate and detailed indicators of the positions of resonances and bound states with good single-particle characters. We report on implementation within our coupled-channels code FRESCO of the charge-exchange interaction term that transforms an incident proton into a neutron. Isobaric analog resonances are seen as peaks in gamma-ray spectrum when the proton is transformed into a neutron at an energy near a neutron bound state. The Lane coupled-channels formalism was extended to follow the nonorthogonality of this neutron channel with that configuration of an inelastic outgoing proton, and the target being left in a particle-hole excited state. This is tested for 208Pb, for which good (p,p g)

  13. Coupled-channel Treatment of Isobaric Analog Resonances in (p,p?) Capture Processes

    NASA Astrophysics Data System (ADS)

    Thompson, I. J.; Arbanas, G.

    2014-04-01

    With the advent of nuclear reactions on unstable isotopes, there has been a renewed interest in using isobaric analogue resonances (IAR) as a tool for probing the nuclear structure. The position and width of isobaric analogue resonances in nucleon-nucleus scattering are accurate and detailed indicators of the positions of resonances and bound states with good single-particle characters. We report on implementation within our coupled-channels code FRESCO of the charge-exchange interaction term that transforms an incident proton into a neutron. Isobaric analog resonances are seen as peaks in ?-ray spectrum when the proton is transformed into a neutron at an energy near a neutron bound state. The Lane coupled-channels formalism was extended to follow the non-orthogonality of this neutron channel with that configuration of an inelastic outgoing proton, and the target being left in a particle-hole excited state. This is tested for 208Pb, for which good (p,p'?) coincidence data exists.

  14. High-pressure phase equilibria with compressed gases

    E-print Network

    Ren, Wei; Scurto, Aaron M.

    2007-01-01

    An apparatus is described that is capable of determining high-pressure vapor-liquid equilibrium, liquid-liquid equilibrium, solid-liquid-vapor equilibrium, vapor-liquid-liquid equilibrium, and mixture critical points and transitions. The device...

  15. Réponse de flotteurs isobares dérivants dans un régime de convection profonde en mer du GroenlandDrifting isobaric float response to deep convective activity in the Greenland Sea

    NASA Astrophysics Data System (ADS)

    Lherminier, Pascale; Gascard, Jean-Claude

    1998-03-01

    During 60 days in 1993 and 100 days in 1994, 15 VCM (vertical current meter) floats similar to those of John Swallow drifted between 300 and 1 100 m depth in the Greenland Sea ( figures 1 and 2), which is considered today as one of the main sources of the north-western Atlantic Deep Waters. Floats were located 6 times per day relative to a moored array composed of three acoustic beacons. They were measuring several in situ parameters characterizing deep convection in this area. Large vertical water displacements of several kilometers, evidencing deep convective events, have been observed by these floats measuring the vertical component of the local current, while drifting along constant isobars at intermediate depths (300-500 m).

  16. Three-pion exchange nucleon-nucleon potentials with virtual $?$-isobar excitation

    E-print Network

    N. Kaiser

    2015-04-20

    The nucleon-nucleon interaction arising from the exchange of three pions and the excitation of $\\Delta(1232)$-isobars in intermediate states is studied. Approximating the $\\Delta$-propagator by the inverse $\\Delta$N mass-splitting, analytical expressions are derived for the spectral-functions of the isoscalar and isovector central, spin-spin and tensor NN-potentials in momentum-space. A trans- lation of the spectral-functions into coordinate-space potentials reveals that the main effect of these specific exchange and excitation mechanisms is a repulsive isoscalar central NN-potential.

  17. Improved Thermometer from Intermediate Mass Fragments in Heavy-Ion Collisions with Isobaric Yield Ratio Difference

    E-print Network

    Chun-Wang Ma; Tian-Tian Ding; Chun-Yuan Qiao; Xi-Guang Cao

    2015-11-30

    \\item[Background] Temperature is an important parameter in studying many important questions in heavy-ion collisions. A thermometer based on the isobaric yield ratio (IYR) has been proposed [Ma \\textit{et al.}, Phys. Rev. C \\textbf{86}, 054611 (2012) and Ma \\textit{et al.}, \\textit{ibid.}, Phys. Rev. C \\textbf{88}, 014609 (2013)]. \\item[Purpose] An improved thermometer ($T_{IB}$) is proposed based on the difference between IYRs. $T_{IB}$ obtained from isobars in different reactions will be compared. \\item[Methods] The yields of three isobars are employed in $T_{IB}$. The residual free energy of the three isobars are replaced by that of the binding energy. No secondary decay modification for odd $A$ fragment is used in $T_{IB}$. \\item[Results] The measured fragment yields in the 140$A$ MeV $^{40, 48}$Ca + $^{9}$Be ($^{181}$Ta) and $^{58, 64}$Ni + $^9$Be ($^{181}$Ta), the 1$A$ GeV $^{124, 136}$Xe + Pb, and the $^{112,124}$Sn + $^{112,124}$Sn reactions have been analyzed to obtain $T_{IB}$ from IMFs. $T_{IB}$ from most of the fragments in the $^{40, 48}$Ca and $^{58, 64}$Ni reactions is in the range of 0.6 MeV $ < T_{IB} < $ 3.5 MeV. $T_{IB}$ from most of the fragments in the $^{124}$Xe and $^{112,124}$Sn reactions is in the range of 0.5 MeV $ < T_{IB} < $ 2.5 MeV, while the range is 0.5 MeV $ < T_{IB} <$ 4 MeV from most of the fragments in the $^{136}$Xe reaction. In general, for most of the fragments $T_{IB}$ in the $^{40, 48}$Ca and $^{58, 64}$Ni reactions are very similar (except in the very neutron-rich fragments), and $T_{IB}$ from IMFs in the $^{124, 136}$Xe and $^{112,124}$Sn reactions is also similar. A slightly dependence of $T_{IB}$ on $A$ is found. \\item[Conclusions] Using the binding energy of the nucleus, $T_{IB}$ can be obtained without the knowledge of the free energies of fragments. In the investigated reactions, $T_{IB}$ from most of the IMFs is low.

  18. A universal method for calculating isobaric-isothermal sections of ternary system phase diagrams

    NASA Astrophysics Data System (ADS)

    Voskov, A. L.; Voronin, G. F.

    2010-04-01

    A method for calculating and constructing isobaric-isothermal sections of ternary system phase diagrams with the use of convex hulls was developed. The method is based on the projection of the singularities of the lower part of the Gibbs energy convex hull onto the plane of component mole fractions followed by a geometric analysis of the properties of this projection. The method is applicable to a wide range of ternary systems, it can be used to find tie-line coordinates and determine the phase compositions of all the diagram regions. The quality of the suggested algorithm was estimated, and examples of the construction of several phase diagrams are given.

  19. Coefficients of the isobaric mass equation and their correlations with various nuclear parameters

    SciTech Connect

    Britz, J.; Pape, A.; Antony, M.S.

    1998-05-01

    The coefficients of the isobaric multiplet mass equation M = a + bT{sub z} + cT{sub z}{sup 2} have been calculated for the 430 identified T = 1/2, 1, 3/2, 2 multiplets and correlations of its b, c coefficients with various nuclear parameters have been sought. For most mass numbers A there is a tendency for b to increase, and for c to decrease, with the average excitation energy of the multiplet. There seems to be no separate dependence of b or c on spin, but there could be a dependence of b on parity.

  20. The MR-TOF-MS isobar separator for the TITAN facility at TRIUMF

    NASA Astrophysics Data System (ADS)

    Jesch, Christian; Dickel, Timo; Plaß, Wolfgang R.; Short, Devin; Ayet San Andres, Samuel; Dilling, Jens; Geissel, Hans; Greiner, Florian; Lang, Johannes; Leach, Kyle G.; Lippert, Wayne; Scheidenberger, Christoph; Yavor, Mikhail I.

    2015-05-01

    At TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) will extend TITAN's capabilities and facilitate mass measurements and in-trap decay spectroscopy of exotic nuclei that so far have not been possible due to strong isobaric contamination. This MR-TOF-MS will also enable mass measurements of very short-lived nuclides (half-life > 1 ms) that are produced in very low quantities (a few detected ions overall). In order to allow the installation of an MR-TOF-MS in the restricted space on the platform, on which the TITAN facility is located, novel mass spectrometric methods have been developed. Transport, cooling and distribution of the ions inside the device is done using a buffer gas-filled RFQ-based ion beam switchyard. Mass selection is achieved using a dynamic retrapping technique after time-of-flight analysis in an electrostatic isochronous reflector system. Only due to the combination of these novel methods the realization of an MR-TOF-MS based isobar separator at TITAN has become possible. The device has been built, commissioned off-line and is currently under installation at TITAN.

  1. Breakdown of the Isobaric Multiplet Mass Equation for the A =20 and 21 Multiplets

    NASA Astrophysics Data System (ADS)

    Gallant, A. T.; Brodeur, M.; Andreoiu, C.; Bader, A.; Chaudhuri, A.; Chowdhury, U.; Grossheim, A.; Klawitter, R.; Kwiatkowski, A. A.; Leach, K. G.; Lennarz, A.; Macdonald, T. D.; Schultz, B. E.; Lassen, J.; Heggen, H.; Raeder, S.; Teigelhöfer, A.; Brown, B. A.; Magilligan, A.; Holt, J. D.; Menéndez, J.; Simonis, J.; Schwenk, A.; Dilling, J.

    2014-08-01

    Using the Penning trap mass spectrometer TITAN, we performed the first direct mass measurements of Mg20,21, isotopes that are the most proton-rich members of the A =20 and A=21 isospin multiplets. These measurements were possible through the use of a unique ion-guide laser ion source, a development that suppressed isobaric contamination by 6 orders of magnitude. Compared to the latest atomic mass evaluation, we find that the mass of Mg21 is in good agreement but that the mass of Mg20 deviates by 3?. These measurements reduce the uncertainties in the masses of Mg20,21 by 15 and 22 times, respectively, resulting in a significant departure from the expected behavior of the isobaric multiplet mass equation in both the A =20 and A=21 multiplets. This presents a challenge to shell model calculations using either the isospin nonconserving universal sd USDA and USDB Hamiltonians or isospin nonconserving interactions based on chiral two- and three-nucleon forces.

  2. Rapid differentiation of isobaric and positional isomers of structurally related glycosides from Phytolacca bogotensis.

    PubMed

    Montoya, Guillermo; Arango, Gabriel J; Ramírez-Pineda, José R

    2009-11-01

    Through the action of glycosyltransferases, a plant can biosynthetically assemble small different aglycons or 'templates' to various polysaccharides to produce numerous glycoconjugates differing in the type of the attached aglycon, the anomeric configuration of C-1 of the glycosylating sugar, the type of sugar and the different position of attachments of the sugar unit present in the polysaccharide chain. The position of attachments and the anomeric configuration of the different sugar present in the polysaccharide create the opportunity to generate molecules with either the same or very close molecular weights, which have relative structural similarity--forming isobaric and positional isomers. Although isomeric differentiation was once considered outside of the domain of mass spectrometry, this task can now be resolved using tandem mass spectrometry. In a standardized purified glycoconjugate fraction (SPT01) from Phytolacca bogotensis, we report conventional electrospray ionization mass spectrometry and collision-induced dissociation (CID) MS/MS parameters which favored the formation of characteristic product ions. This allowed us to suggest the type of sugar linkages present in a specific glycoconjugate. Ten new glycoconjugate are described from this plant and another twelve known saponins were structurally characterized using the automatic MSn acquisition mode. The differentiation of two pairs of positional isomers and four isobaric glycosides and the production of a library of 30 glycosides present in P. bogotensis were accomplished. PMID:19785003

  3. Two-proton decay from Isobaric Analog States of light nuclei

    NASA Astrophysics Data System (ADS)

    Brown, Kyle

    2014-03-01

    Recent experiments at the National Superconducting Cyclotron Laboratory at Michigan State University using the charged-particle array HiRA and the gamma-ray array CAESAR have shed light on a new class of two-proton emitters associated with Isobaric Analog States (IAS). The two-proton decay is to the Isobaric Analog state of the daughter, which then gamma decays. These isospin-allowed transitions occur when one-proton decays are forbidden by either energy or isospin conservation, and when two-proton decay to the ground state is isospin forbidden. Three possible examples of this decay path will be discussed (8BIAS, 12NIAS, and 16FIAS) . The known IAS of 8C in 8B was confirmed to decay by two-proton emission to the 3.56 MeV IAS in 6Li. While the IAS in 8B was previously known, it was measured in this experiment with unbiased statistics and in coincidence with the 3.56 MeV gamma-ray. The IAS in 16F was investigated for the first time in this experiment and is still under investigation. Previous work on the IAS of 12O in 12N at the Cyclotron Institute at Texas A&M will also be presented.

  4. Zr/Nb isobar separation experiment for future 93Zr AMS measurement

    NASA Astrophysics Data System (ADS)

    Lu, W.; Anderson, T.; Bowers, M.; Bauder, W.; Collon, P.; Kutschera, W.; Kashiv, Y.; Lachner, J.; Martschini, M.; Ostdiek, K.; Robertson, D.; Schmitt, C.; Skulski, M.; Steier, P.

    2015-10-01

    93Zr (t1/2 = 1.6 Ma) is mostly produced by the main s-process in low-to-intermediate mass AGB stars. Large uncertainty exists in the current 92Zr(n,?)93Zr Maxwellian Average cross section. This could have significant impact on nucleosynthesis calculations. Large amounts of 93Zr are also produced in nuclear reactors and pose long-term environmental radioactivity. Hence, measurement of 93Zr by the AMS is important for both fields above. We report here on progress in the development of AMS method to measure 93Zr. Compared with 98 MeV beam energy, Zr/Nb isobar position separation was improved using 155.2 MeV beam energy and Gas-Filled Magnet. Energy loss measurement with increased beam energy inside the detector indicates that higher beam energy can improve isobar energy loss separation. A chemical procedure to reduce the Nb content in Zr samples has been developed and tested. It reduces the 93Nb content by a factor of 1000.

  5. Breakdown of the isobaric multiplet mass equation for the A = 20 and 21 multiplets.

    PubMed

    Gallant, A T; Brodeur, M; Andreoiu, C; Bader, A; Chaudhuri, A; Chowdhury, U; Grossheim, A; Klawitter, R; Kwiatkowski, A A; Leach, K G; Lennarz, A; Macdonald, T D; Schultz, B E; Lassen, J; Heggen, H; Raeder, S; Teigelhöfer, A; Brown, B A; Magilligan, A; Holt, J D; Menéndez, J; Simonis, J; Schwenk, A; Dilling, J

    2014-08-22

    Using the Penning trap mass spectrometer TITAN, we performed the first direct mass measurements of (20,21)Mg, isotopes that are the most proton-rich members of the A = 20 and A = 21 isospin multiplets. These measurements were possible through the use of a unique ion-guide laser ion source, a development that suppressed isobaric contamination by 6 orders of magnitude. Compared to the latest atomic mass evaluation, we find that the mass of (21)Mg is in good agreement but that the mass of (20)Mg deviates by 3 ?. These measurements reduce the uncertainties in the masses of (20,21)Mg by 15 and 22 times, respectively, resulting in a significant departure from the expected behavior of the isobaric multiplet mass equation in both the A = 20 and A = 21 multiplets. This presents a challenge to shell model calculations using either the isospin nonconserving universal sd USDA and USDB Hamiltonians or isospin nonconserving interactions based on chiral two- and three-nucleon forces. PMID:25192091

  6. Transverse electron scattering response function of {sup 3}He with {Delta}-isobar degrees of freedom

    SciTech Connect

    Yuan Luping; Efros, Victor D.; Leidemann, Winfried; Tomusiak, Edward L.

    2010-11-15

    A calculation of the {sup 3}He transverse (e,e{sup '}) inclusive response function, R{sub T}, which includes {Delta} degrees of freedom, is performed using the Lorentz integral transform method. The resulting coupled equations are treated in impulse approximation, where the NNN and NN{Delta} channels are solved separately. As NN and NNN potentials, we use the Argonne V18 and Urbana IX models, respectively. Electromagnetic currents include the {Delta}-isobar currents, one-body N currents with relativistic corrections, and two-body currents consistent with the Argonne V18 potential. R{sub T} is calculated for the breakup threshold region at momentum transfers near 900 MeV/c. Our results are similar to those of Deltuva et al. in that large {Delta}-isobar current contributions are found. However, we find that these are largely canceled by the relativistic contribution from the one-body N currents. Finally, a comparison is made between theoretical results and experimental data.

  7. Equilibrium and nonequilibrium molecular dynamics methods for determining solidliquid phase coexistence at equilibrium

    E-print Network

    agreement with those obtained by alternative simulation methods for phase equilibria. © 2003 American to determine vapor­liquid and liquid­liquid phase equilibria. However, it is of limited usefulness for solid­ liquid phase equilibria because of the difficulty of inserting particles in the solid phase

  8. Finite-size and truncation effects for microscopic expressions for the temperature at equilibrium and nonequilibrium.

    PubMed

    Lervik, Anders; Wilhelmsen, Øivind; Trinh, Thuat T; Nagel, Henrik Rojas

    2015-09-21

    Several expressions have been proposed for the temperature in molecular simulations, where some of them have configurational contributions. We investigate how their accuracy is influenced by the number of particles in the simulation and the discontinuity in the derivatives of the interaction potential introduced by truncation. For equilibrium molecular dynamics with fixed total volume and fixed average total energy per particle, all the evaluated expressions including that for the kinetic temperature give a dependence on the total number of particles in the simulation. However, in a partitioned simulation volume under the same conditions, the mean temperature of each bin is independent of the number of bins. This finding is important for consistently defining a local temperature for use in nonequilibrium simulations. We identify the configurational temperature expressions which agree most with the kinetic temperature and find that they give close to identical results in nonequilibrium molecular dynamics (NEMD) simulations with a temperature gradient, for high and low density bulk-systems (both for transient and steady-state conditions), and across vapor-liquid interfaces, both at equilibrium and during NEMD simulations. The work shows that the configurational temperature is equivalent to the kinetic temperature in steady-state molecular dynamics simulations if the discontinuity in the derivatives of the interaction potential is handled properly, by using a sufficiently long truncation-distance or tail-corrections. PMID:26395686

  9. Thermodynamic and structure-property study of liquid-vapor equilibrium for aroma compounds.

    PubMed

    Tromelin, Anne; Andriot, Isabelle; Kopjar, Mirela; Guichard, Elisabeth

    2010-04-14

    Thermodynamic parameters (T, DeltaH degrees , DeltaS degrees , K) were collected from the literature and/or calculated for five esters, four ketones, two aldehydes, and three alcohols, pure compounds and compounds in aqueous solution. Examination of correlations between these parameters and the range values of DeltaH degrees and DeltaS degrees puts forward the key roles of enthalpy for vaporization of pure compounds and of entropy in liquid-vapor equilibrium of compounds in aqueous solution. A structure-property relationship (SPR) study was performed using molecular descriptors on aroma compounds to better understand their vaporization behavior. In addition to the role of polarity for vapor-liquid equilibrium of compounds in aqueous solution, the structure-property study points out the role of chain length and branching, illustrated by the correlation between the connectivity index CHI-V-1 and the difference between T and log K for vaporization of pure compounds and compounds in aqueous solution. Moreover, examination of the esters' enthalpy values allowed a probable conformation adopted by ethyl octanoate in aqueous solution to be proposed. PMID:20222661

  10. Vapor-liquid phase separator studies

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.; Lee, J. M.; Kim, Y. I.; Hepler, W. A.; Frederking, T. H. K.

    1983-01-01

    Porous plugs serve as both entropy rejection devices and phase separation components separating the vapor phase on the downstream side from liquid Helium 2 upstream. The liquid upstream is the cryo-reservoir fluid needed for equipment cooling by means of Helium 2, i.e Helium-4 below its lambda temperature in near-saturated states. The topics outlined are characteristic lengths, transport equations and plug results.

  11. Statistical Equilibrium Dynamics

    E-print Network

    Michael K. -H. Kiessling

    2008-05-03

    The mean-field thermodynamic limit is studied for a class of isolated Newtonian N-body systems whose Hamiltonian admits several invariants of motion. It is shown that the macrostates of individual members of a statistical equilibrium ensemble are not necessarily themselves in a state of global thermal equilibrium in the strict sense. Yet they are always locally in thermodynamic equilibrium, and always global maximizers of the pertinent maximum entropy principle.

  12. Gamow-Teller strength studied through {Gamma}-excitation of isobaric analog states

    SciTech Connect

    Boswell, M. S.; Young, A. R.; Ejiri, H.

    2013-04-19

    We consider a measurement of isobaric analog states (IAS) of 76As in 76Se as a method for measuring the Gamow-Teller (GT) strength important to constrain and possibly help normalize calculations of double beta ({beta}{beta}) decay matrix elements. We show that photo-nuclear reactions via IAS can provide valuable information about the parent and daughter states of {beta}{beta}-decay not currently available from measurements of charge exchange reactions. Several experiments have been proposed at the HI{open_square} Sfacility at the Triangle Nuclear Research Laboratory in Durham, NC, the first of which will measure the lowest 1{sup -}, 1{sup +} and 2{sup +} IAS in {sup 76}Se.

  13. The Defect Diffusion Model and Isochoric Energy and Isobaric Enthalpy for Glass Formers

    NASA Astrophysics Data System (ADS)

    Shlesinger, Michael; Bendler, John; Fontanella, John; Wintersgill, Mary

    2009-03-01

    The defect diffusion model produces stretched exponential relaxation, in supercooled liquids, through the sub-diffusive motion of defects. The aggregation of the defects produces a Vogel-Fulcher type law for the divergence of the time scale at a critical temperature. The model is employed to calculate the ratio of the apparent isochoric activation energy to the isobaric activation enthalpy, EV*/H* or EV/EP,. This ratio measures the relative sensitivity of kinetic processes to changes in volume and temperature respectively. This ratio equation is tested using dielectric relaxation data for poly(vinyl acetate), viscosity data for glycerol and ionic conductivity data for poly(propylene glycol) containing LiCF3SO3. Good agreement between theory and experiment is found using model parameters previously published.

  14. An ion guide laser ion source for isobar-suppressed rare isotope beams

    SciTech Connect

    Raeder, Sebastian Ames, Friedhelm; Bishop, Daryl; Bricault, Pierre; Kunz, Peter; Mjøs, Anders; Heggen, Henning; Institute of Applied Physics, TU Darmstadt, Schlossgartenstr. 7, 64289 Darmstadt ; Lassen, Jens Teigelhöfer, Andrea; Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2

    2014-03-15

    Modern experiments at isotope separator on-line (ISOL) facilities like ISAC at TRIUMF often depend critically on the purity of the delivered rare isotope beams. Therefore, highly selective ion sources are essential. This article presents the development and successful on-line operation of an ion guide laser ion source (IG-LIS) for the production of ion beams free of isobaric contamination. Thermionic ions from the hot ISOL target are suppressed by an electrostatic potential barrier, while neutral radio nuclides effusing out are resonantly ionized by laser radiation within a quadrupole ion guide behind this barrier. The IG-LIS was developed through detailed thermal and ion optics simulation studies and off-line tests with stable isotopes. In a first on-line run with a SiC target a suppression of surface-ionized Na contaminants in the ion beam of up to six orders of magnitude was demonstrated.

  15. The current status of Zr-Nb isobar separation experiments for future 93Zr AMS measurement

    NASA Astrophysics Data System (ADS)

    Lu, Wenting; Collon, Philippe; Kashiv, Yoav; Robertson, Daniel; Schmitt, Christopher; Bowers, Matthew; Ostdiek, Karen; Bauder, William

    2013-10-01

    The rare isotope 93Zr (t1/2 = 1.6 Ma) can be produced (1) in the s-process, (2) by the spontaneous fission of Uranium and Plutonium, and (3) by the activation of cladding Zr in nuclear reactors. The production method (1) makes it relevant in astrophysical modeling of nucleosynthesis processes, while (2) and (3) makes it of interest to people dealing with nuclear waste management and transmutation study. The main challenge in AMS detection of 93Zr is the adequate separation from its stable isobar 93Nb which is only one atomic number away. The nuclear Science Laboratory at the University of Notre Dame is developing the capability to measure 93Zr by AMS, featuring the combination of gas-filled magnet with the position-sensitive parallel grid avalanche counter and gas chamber (ionization chamber and Bragg curve detector). The chemical reduction and the suppression in the ion source of 93Nb have been deemed as necessary.

  16. A new gas lesion syndrome in man, induced by 'isobaric gas counterdiffusion'

    NASA Technical Reports Server (NTRS)

    Lambertsen, C. J.; Idicula, J.

    1975-01-01

    Normal men have been found to develop pruritis and gas bubble lesions in the skin, and disruption of vestibular function, when breathing nitrogen or neon with oxygen while surrounded by helium at increased ambient pressure. This phenomenon, which occurs at stable ambient pressures, at 1 or many ATA, has been designated the isobaric gas counterdiffusion syndrome. In a series of analyses and experiments in vivo and in vitro the cause of the syndrome has been established as due to gas accumulation and development of gas bubbles in tissues as a result of differences in selective diffusivities, for various respired and ambient gases, in the tissue substances between capillary blood and the surrounding atmosphere. The phenomenon described in man is an initial stage of a process shown later in animals to progress to continuous, massive, lethal, intravascular gas embolization.

  17. Split isobaric analog state in 55Ni: case of strong isospin mixing.

    PubMed

    Tripathi, Vandana; Tabor, S L; Volya, A; Liddick, S N; Bender, P C; Larson, N; Prokop, C; Suchyta, S; Tai, P-L; Vonmoss, J M

    2013-12-27

    Study of ?+ decay of the exotic Tz=-3/2 nucleus 55Cu, via delayed ? rays, has revealed a strongly isospin mixed doublet (4599-4579 keV) in 55Ni, which represents the fragmented and previously unknown isobaric analog of the ground state of 55Cu. The observed small log?ft values to both states in the doublet confirm the superallowed Fermi ? decay. The near degeneracy of a pair of 3/2- levels in 55Ni results in the strong isospin mixing. The isospin mixing matrix element between the T=3/2 and T=1/2 levels is inferred from the experiment to be 9(1) keV, which agrees well with the matrix element of the charge symmetry breaking shell model Hamiltonian of Ormand and Brown. A precise value of the half-life of 55Cu at 57(3) ms was also obtained. PMID:24483792

  18. A Precise, Simple, and Low-Cost Experiment to Determine the Isobaric Expansion Coefficient for Physical Chemistry Students

    ERIC Educational Resources Information Center

    Pe´rez, Eduardo

    2015-01-01

    The procedure of a physical chemistry experiment for university students must be designed in a way that the accuracy and precision of the measurements is properly maintained. However, in many cases, that requires costly and sophisticated equipment not readily available in developing countries. A simple, low-cost experiment to determine isobaric

  19. THE JOURNAL OF CHEMICAL PHYSICS 143, 154108 (2015) Nested sampling of isobaric phase space for the direct evaluation

    E-print Network

    Nielsen, Steven O.

    2015-01-01

    THE JOURNAL OF CHEMICAL PHYSICS 143, 154108 (2015) Nested sampling of isobaric phase space 2015) Nested Sampling (NS) is a powerful athermal statistical mechanical sampling technique method called Nested Sampling (NS) provides a simple yet powerful way to compute partition functions

  20. Ultrahigh-temperature metamorphism under isobaric heating: New evidence from the North China Craton

    NASA Astrophysics Data System (ADS)

    Yang, Qiong-Yan; Santosh, M.; Tsunogae, Toshiaki

    2014-12-01

    The Khondalite Belt within Inner Mongolia Suture Zone (IMSZ) in the North China Craton (NCC) preserves evidence for extreme crustal metamorphism under ultra-high temperature (UHT) conditions at ca. 1.92 Ga, associated with the subduction-collision tectonics between the Yinshan and Ordos Blocks. Here we report a new locality in Hongsigou where cordierite- and spinel-bearing granulites record UHT metamorphism. The prograde, peak, and retrograde mineral assemblages in these pelitic granulites have been identified based on petrography and mineral chemistry as: Bt1 + Grt1 + Sil1 + Kfs1 + Pl1 + Ilm + Qtz1, Grt1 + Sil2 + Kfs2 + Pl2 + Spl + Ilm + Qtz2 + Liq, and Crd + Grt2 + Sil3 + Kfs2 + Pl2 + Ilm + Qtz2 respectively. The peak metamorphic conditions of the pelitic granulite were estimated as 930-1050 °C and 6.5-7.5 kbar based on pseudosection analysis in the system NCKFMASHTO, suggesting extreme thermal metamorphism. We report LA-ICPMS zircon U-Pb data from the granulite which show weighted mean 207Pb/206Pb age of 1881 ± 6.6 Ma, marking the timing of UHT metamorphism. Lu-Hf analyses of the zircons show ?Hf(t) values within a restricted range of -4.2 to 0.3 and together with Hf model ages, a Paleoproterozoic arc magmatic source is inferred for the detrital zircons. The estimated P-T path for the UHT granulite suggests isobaric heating followed by cooling and decompression along a clockwise trajectory, different from the anti-clockwise P-T paths defined in earlier studies for the 1.92 Ga UHT rocks from the IMSZ. The younger age and the isobaric heating trajectory suggest that the Hongsigou UHT rocks are related to heat input from underplated mafic magmas following continental collision.

  1. High-pressure vapor-liquid equilibria for CO[sub 2] + benzonitrile, CO[sub 2] + benzyl alcohol, CO[sub 2] + 2-tert-butylphenol, CO[sub 2] + methoxybenzene, and CO[sub 2] + 1,2,3,4-Tetrahydronaphthalene at temperatures between 313 and 393 K and pressures up to 20 MPa

    SciTech Connect

    Walther, D.; Maurer, G. )

    1993-04-01

    High-pressure vapor-liquid equilibria are reported for CO[sub 2] + benzonitrile, CO[sub 2] + benzyl alcohol, CO[sub 2] + 1-tert-butylphenol, CO[sub 2] + methoxybenzene, and CO[sub 2] + 1,2,3,4-tetrahydronaphthalene at three temperatures from 313 to 393 K and pressures up to 20 MPa. The investigations were made by using a flow-type apparatus. The results for CO[sub 2] + methoxybenzene are compared to literature values. On the other systems no literature values are available.

  2. Comparison between intrathecal isobaric ropivacaine-fentanyl and bupivacaine-fentanyl in elective infraumbilical orthopedic surgery: A randomized controlled study

    PubMed Central

    Layek, Amitava; Maitra, Souvik; Gozi, Nitish K; Bhattacharjee, Sulagna; Pal, Sugata; Sen, Suvadeep; Hazra, Avijit

    2015-01-01

    Background and Aims: We aimed to evaluate and compare the block characteristics and duration of analgesia of intrathecal isobaric ropivacaine-fentanyl and bupivacaine-fentanyl combination in adult patients undergoing lower limb orthopedic surgery. Material and Methods: Seventy-four American Society of Anesthesiologists’ I and II adult patients undergoing lower limb orthopedic surgery under subarachnoid block were randomized to receive either 3 ml 0.5% isobaric ropivacaine and 25 mcg fentanyl (Group R) or 3 ml 0.5% isobaric bupivacaine and 25 mcg fentanyl (Group B). The hemodynamic profiles, maximum upper level of sensory block height, time to reach peak block height, two dermatome regression time, and duration of motor block were recorded. Results: There was no statistically significant difference regarding the hemodynamic parameters between the groups. The median (range) peak sensory block height was T7 (T4-T9) in Group R and T7 (T4-T10) in Group B. Time to reach peak block height (13.2 ± 2.3 min in Group R vs. 13.7 ± 2.2 min in Group B; P = 0.385) was similar between the groups. Two dermatome regression time in sensory block (median 120 min vs. 85 min; P < 0.001) and duration of motor block (median 245 min vs. 150 min; P < 0.001) was significantly higher in Group B. The duration of analgesia (median 360 min vs. 245 min; P < 0.001) was significantly higher in the bupivacaine group. Conclusion: Intrathecal isobaric bupivacaine-fentanyl combination produces a significantly longer duration of analgesia, sensory block and motor block than isobaric ropivacaine-fentanyl combination. As ropivacaine has a shorter duration of sensory and motor block, it may be preferred in day care surgery. PMID:26702216

  3. Getting Freshman in Equilibrium.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 1983

    1983-01-01

    Various aspects of chemical equilibrium were discussed in six papers presented at the Seventh Biennial Conference on Chemical Education (Stillwater, Oklahoma 1982). These include student problems in understanding hydrolysis, helping students discover/uncover topics, equilibrium demonstrations, instructional strategies, and flaws to kinetic…

  4. Equilibrium of KSTAR Plasma

    NASA Astrophysics Data System (ADS)

    You, K.-I.; Lee, D.-K.; Lee, S. G.; Bak, J. G.; Hahn, S. H.; Lao, L.; Kstar Team

    2011-10-01

    We have installed the EFIT code on our computing system and made some modification to reconstruct the plasma equilibrium of KSTAR (Korea Superconducting Tokamak Advanced Research). KSTAR PF and TF coil systems use a CICC (Cable-In-Conduit Conductor) type superconductor. The CICC jacket material for most PF and all TF coils is Incoloy 908, which is a magnetic material with relative magnetic permeability greater than 10 in low external field. We newly introduced Diamagnetic Loop and variational Motion Stark Effect signals to equilibrium reconstruction. In this paper, we present some results of equilibrium reconstruction with the EFIT code, assess the effects of newly introduced diagnsotics signal on the equilibrium reconstruction and compare the EFIT results with the various diagnostics data in various plasma conditions including H- and L- modes. In addition, we will show the Incoloy908 effects on the plasma equilibrium.

  5. Computing the Electricity Market Equilibrium: Uses of market equilibrium models

    E-print Network

    Baldick, Ross

    1 Computing the Electricity Market Equilibrium: Uses of market equilibrium models Ross Baldick Abstract--In this paper we consider the formulation and uses of electric- ity market equilibrium models. Keywords--Electricity market, Equilibrium models I. INTRODUCTION Electricity market equilibrium modelling

  6. Isobar suppression for measurement of silicon-32 by accelerator mass spectrometry at low energy

    NASA Astrophysics Data System (ADS)

    Treacy, Donald John, Jr.

    2000-10-01

    Development of a method to suppress the isobaric interference, 32S, for the purpose of measuring 32Si by Accelerator Mass Spectrometry (AMS) at low energy was undertaken. The differential energy loss of the ions when transmitted through a thin carbon foil was the basis of the isobaric suppression. A new silica reduction technique was developed for the purpose of increasing ion source output for silicon samples. The energy loss and energy straggle of the transmitted ions, the charge state distributions, and beamline transmission were measured for the stable isotopes of silicon and 32S for the development of the method. The data are compared to the predictions that were made for the ion beam energy loss and energy straggle using the Monte Carlo simulation program TRIM. The charge state distribution data are compared to predictions made using empirical formulas developed by Chaki and Elmore in 1980. The negative silicon ion beam source output for chemically prepared Mg 2Si samples was increased from approximately 10 nA to approximately 15 ?A. This was an increase of a factor of approximately 103 over naturally occurring SiO2 samples. The observed energy loss profiles of the silicon and sulfur ions through carbon foils of 50-?g/cm2, 75-?g/cm2, and 100-?g/cm2 are in good agreement with the predicted values, with absolute percent error results ranging from 0.1% to 2.5%. The measured energy straggling for the silicon and sulfur ions in the thin carbon foils ranged from approximately 150 keV to 450 keV. This is much larger than the values of 21 keV to 30 keV that were predicted using simulations from the TRIM code. The measured charge state distributions were in very good agreement with the predicted distributions for silicon and sulfur. The overall system ion beam transmission efficiency was 0.2% for the transmission to the spectrograph, and 0.02% to the silicon surface barrier detector in the spectrograph. The results indicate that enacting the differential energy loss for the silicon- sulfur pair suppressed the sulfur interference by a factor of 106 relative to the silicon count rate.

  7. FRICTIONAL EQUILIBRIUM POSTURES FOR ROBOTIC

    E-print Network

    Rimon, Elon

    FRICTIONAL EQUILIBRIUM POSTURES FOR ROBOTIC LOCOMOTION - COMPUTATION, GEOMETRIC CHARACTERIZATION, AND STABILITY ANALYSIS YIZHAR OR #12;FRICTIONAL EQUILIBRIUM POSTURES FOR ROBOTIC LOCOMOTION - COMPUTATION grasping and manipulation . . . . . . . . . . . . . . 6 1.1.3 Dynamic stability of frictional equilibrium

  8. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  9. TEA: Thermal Equilibrium Abundances

    NASA Astrophysics Data System (ADS)

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2015-05-01

    TEA (Thermal Equilibrium Abundances) calculates gaseous molecular abundances under thermochemical equilibrium conditions. Given a single T,P point or a list of T,P pairs (the thermal profile of an atmosphere) and elemental abundances, TEA calculates mole fractions of the desired molecular species. TEA uses 84 elemental species and thermodynamical data for more then 600 gaseous molecular species, and can adopt any initial elemental abundances.

  10. Temperature determined by isobaric yield ratio in heavy-ion collisions

    E-print Network

    Ma, C W; Ma, Y G; Wada, R; Wang, S S; 10.1103/PhysRevC.86.054611

    2012-01-01

    This work focuses on the study of temperature associated with the final heavy fragments in reactions induced by both the neutron-proton symmetric and the neutron-rich projectiles, and with incident energy ranges from 60$A$ MeV to 1$A$ GeV. Isobaric yield ratio (IYR) is used to determine the temperature of heavy fragments. Cross sections of measured fragment in reactions are analyzed, and a modified statistical abrasion-ablation (SAA) model is used to calculate the yield of fragment in 140$A$ MeV $^{64}$Ni + $^{9}$Be and 1$A$ GeV $^{136}$Xe + $^{208}$Pb reactions. Relatively low $T$ of heavy fragments are obtained in different reactions ($T$ ranges from 1 to 3MeV). $T$ is also found to depend on the neutron-richness of the projectile. The incident energy affects $T$ very little. $\\Delta\\mu/T$ (the ratio of the difference between the chemical potential of neutron and proton to temperature) is found to increase linearly as $N/Z$ of projectile increases. It is found that $T$ of the $^{48}$Ca reaction, for which I...

  11. Extraction of the symmetry energy coefficients from the masses differences of isobaric nuclei

    E-print Network

    Junlong Tian; Haitao Cui; Kuankuan Zheng; Ning Wang

    2014-03-28

    The nuclear symmetry energy coefficients of finite nuclei are extracted by using the differences between the masses of isobaric nuclei. Based on the masses of more than 2400 nuclei with $A=9-270$, we investigate the model dependence in the extraction of symmetry energy coefficient. We find that the extraction of the symmetry energy coefficients is strongly correlated with the forms of the Coulomb energy and the mass dependence of the symmetry energy coefficient adopted. The values of the extracted symmetry energy coefficients increase by about 2 MeV for heavy nuclei when the Coulomb correction term is involved. We obtain the bulk symmetry energy coefficient $S_0=28.26\\pm1.3$ MeV and the surface-to-volume ratio $\\kappa=1.26\\pm 0.25 $ MeV if assuming the mass dependence of symmetry energy coefficient $a_{\\rm sym}(A)=S_0(1-\\kappa/A^{1/3})$, and $S_0=32.80\\pm1.7$ MeV, $\\kappa=2.82\\pm0.57$ MeV when $a_{\\rm sym}(A)=S_0 (1+\\kappa/A^{1/3})^{-1}$ is adopted.

  12. Precision Test of the Isobaric Multiplet Mass Equation in the A = 32, T = 2 Quintet

    NASA Astrophysics Data System (ADS)

    Ferrer, R.; Kwiatkowski, A. A.; Bollen, G.; Campbell, C. M.; Folden, C. M., III; Lincoln, D.; Morrissey, D. J.; Pang, G. K.; Prinke, A.; Savory, J.; Schwarz, S.

    2008-10-01

    Masses of the radionuclides ^32,33Si and ^34P and of the stable nuclide ^32S have been measured with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. Relative mass uncertainties of 3 x 10-8 and better have been achieved. The measured mass value of ^32Si differs from the literature value [1,2] by four standard deviations. The precise mass determination of ^32Si and ^32S have been employed to test the isobaric multiplet mass equation for the A = 32, T= 2 isospin quintet. The experimental results indicate a significant deviation from the quadratic form. This work has been supported by Michigan State University, the NSF under contract number PHY- 0606007, and the DOE under the contract DE-FG02-00ER41144. References: 1. G. Audi, A.H. Wapstra, and C. Thibault, Nucl. Phys. A729 (2003) 337 2. A. Paul, S. R"ottger, A. Zimbal, and U. Keyser, Hyperfine Interact. 132 (2001) 189

  13. Differentiating Isobaric Steroid Hormone Metabolites Using Multi-Stage Tandem Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Tedmon, Lauren; Barnes, Jeremy S.; Nguyen, Hien P.; Schug, Kevin A.

    2013-03-01

    Steroid hormones and their metabolites are currently undergoing clinical trials as potential therapeutics for traumatic brain injury (TBI). To support this work, it is necessary to develop improved procedures for differentiating isobaric species in this compound class. Equilin sulfate (E-S), estrone sulfate (E1-S), 17?-dihydroequilin sulfate (ADHE-S), and 17?-dihydroequilin sulfate (BDHE-S) are primary constituents in hormone replacement therapies, such as Premarin, which are among pharmaceuticals being investigated for TBI treatment. The latter three compounds are isomers and can be difficult to differentiate in trace analytical determinations. In this work, a systematic study of the fragmentation of ADHE-S, BDHE-S, E1-S, and E-S under different stages of higher order tandem mass spectrometry (MSn) and variation of collision energy, allowed optimization of conditions for distinguishing the isomeric structures. For epimeric variants (e.g., ADHE-S versus BDHE-S; ?- versus ?-stereoisomerization in the C-17 position), differentiation was achieved at MS4 and fragmentation was demonstrated through MS5. Computational analysis was performed to further explore differences in the fragmentation pathways due to changes in stereochemistry.

  14. Excitation energies of double isobar-analog states in heavy nuclei

    SciTech Connect

    Poplavskii, I. V.

    1988-12-01

    Several new relationships are established for isomultiplets on the basis of a theory in which the Coulomb coupling constant (CCC) is allowed to be complex. In particular, the following rule is formulated: the energies for fission or decay of members of an isomultiplet into a charged cluster and members of the corresponding daughter isomultiplet are equidistant. This relationship is well satisfied for isomultiplets with /ital A/less than or equal to60. By extrapolating the rule for fission and decay energies to the region of heavy nuclei, the excitation energies /ital E//sub /ital x// of double isobar-analog states (DIASs) are found for the nuclei /sup 197,199/Hg, /sup 205/Pb, /sup 205 - -209/Po, /sup 209/At, and /sup 238/Pu. A comparison of the computed energies /ital E//sub /ital x// with the experimentally measured values for /sup 208/Po attest to the reliability and good accuracy of the method proposed here when used to determine the excitation energies of DIASs in heavy nuclei.

  15. Effects of isobaric ropivacaine with or without fentanyl in subarachnoid blockade: A prospective double-blind, randomized study

    PubMed Central

    Seetharam, Kaushik Rao; Bhat, Gayathri

    2015-01-01

    Background: The addition of fentanyl to ropivacaine has shown to improve the quality of analgesia without compromising its benefits such as early mobilization and early voiding. Aim: The aim of the study was to evaluate the effects of the isobaric ropivacaine in combination with fentanyl and compare it with the isobaric ropivacaine alone in spinal anesthesia for lower abdominal and lower limb surgeries. Settings and Design: Double-blinded randomized controlled trial. Subjects and Methods: Hundred patients belonging to American Society of Anesthesiologists physical status I and II scheduled for either lower abdominal or lower limb surgery under spinal anesthesia were included. The study was a prospective double-blinded randomized controlled trial where patients were randomly allocated into two groups to receive either 2.5 ml of 0.75% (18.75 mg) isobaric ropivacaine with 25 ?g fentanyl (Group RF) or 2.5 ml of 0.75% (18.75 mg) isobaric ropivacaine with 0.5 ml of 0.9% saline (Group R) intrathecally. Statistical Analysis: Data analysis was done by Student's unpaired t-test. SPSS version 16 was used. P < 0.05 was considered as statistically significant. Results: We found no significant difference in hemodynamics, onset of sensory and motor block, peak level of block, recovery from motor block, return of micturition and incidence of side effects with the addition of fentanyl to ropivacaine. First request for analgesia was required earlier in the control group. There was also a significant prolongation of the duration of sensory block (mean - 341.6 min) and postoperative analgesia in Group RF (mean - 442.2 min) (P < 0.001). Conclusion: The addition of fentanyl to ropivacaine significantly prolongs the duration of postoperative analgesia with clinically insignificant influence on hemodynamics and motor blockade with minimal side effects. PMID:26417123

  16. Systematic Comparison of Label-Free, Metabolic Labeling, and Isobaric Chemical Labeling for Quantitative Proteomics on LTQ Orbitrap Velos

    SciTech Connect

    Li, Zhou; Adams, Rachel M; Chourey, Karuna; Hurst, Gregory {Greg} B; Hettich, Robert {Bob} L; Pan, Chongle

    2012-01-01

    A variety of quantitative proteomics methods have been developed, including label-free, metabolic labeling, and isobaric chemical labeling using iTRAQ or TMT. Here, these methods were compared in terms of the depth of proteome coverage, quantification accuracy, precision, and reproducibility using a high-performance hybrid mass spectrometer, LTQ Orbitrap Velos. Our results show that (1) the spectral counting method provides the deepest proteome coverage for identification, but its quantification performance is worse than labeling-based approaches, especially the quantification reproducibility; (2) metabolic labeling and isobaric chemical labeling are capable of accurate, precise, and reproducible quantification and provide deep proteome coverage for quantification. Isobaric chemical labeling surpasses metabolic labeling in terms of quantification precision and reproducibility; (3) iTRAQ and TMT perform similarly in all aspects compared in the current study using a CID-HCD dual scan configuration. Based on the unique advantages of each method, we provide guidance for selection of the appropriate method for a quantitative proteomics study.

  17. Principles of the equilibrium theory of small multicomponent systems in three aggregate states

    NASA Astrophysics Data System (ADS)

    Tovbin, Yu. K.

    2015-11-01

    Principles of the molecular statistical theory of small multicomponent drops/microcrystals in a three-dimensional bulk and in two-dimensional adsorption systems are developed. Equations of the theory are derived using the cluster approach. The theory describes discrete distributions of molecules in space (on a size scale comparable to the molecular size) and continuous molecular distributions (at short distances inside cells) upon their translational and vibrational motions. The theory provides a unified description of the equilibrium molecular distributions in three aggregate states and at their interfaces. Pair intermolecular interaction potentials (such as the Mie potential) in several coordination spheres that determine lattice structure compressibility are taken into account. For simplicity, it is considered that the sizes of mixture components are virtually the same. Structural cell distribution functions for the transition region of curved interfaces are derived. Expressions for the pressure tensor components inside small bodies are obtained, allowing us to calculate the thermodynamic characteristics of a vapor-liquid interface, including surface tension. Questions regarding the consistency between the theory of phase transitions in small systems and the traditional theory of associate (cluster) formation and the transition to systems limited in the total volume value are discussed.

  18. Equilibrium games in networks

    NASA Astrophysics Data System (ADS)

    Li, Angsheng; Zhang, Xiaohui; Pan, Yicheng; Peng, Pan

    2014-12-01

    It seems a universal phenomenon of networks that the attacks on a small number of nodes by an adversary player Alice may generate a global cascading failure of the networks. It has been shown (Li et al., 2013) that classic scale-free networks (Barabási and Albert, 1999, Barabási, 2009) are insecure against attacks of as small as O(logn) many nodes. This poses a natural and fundamental question: Can we introduce a second player Bob to prevent Alice from global cascading failure of the networks? We proposed a game in networks. We say that a network has an equilibrium game if the second player Bob has a strategy to balance the cascading influence of attacks by the adversary player Alice. It was shown that networks of the preferential attachment model (Barabási and Albert, 1999) fail to have equilibrium games, that random graphs of the Erdös-Rényi model (Erdös and Rényi, 1959, Erdös and Rényi, 1960) have, for which randomness is the mechanism, and that homophyly networks (Li et al., 2013) have equilibrium games, for which homophyly and preferential attachment are the underlying mechanisms. We found that some real networks have equilibrium games, but most real networks fail to have. We anticipate that our results lead to an interesting new direction of network theory, that is, equilibrium games in networks.

  19. Temperature determined by isobaric yield ratio in heavy-ion collisions

    E-print Network

    C. W. Ma; J. Pu; Y. G. Ma; R. Wada; S. S. Wang

    2012-12-01

    This work focuses on the study of temperature associated with the final heavy fragments in reactions induced by both the neutron-proton symmetric and the neutron-rich projectiles, and with incident energy ranges from 60$A$ MeV to 1$A$ GeV. Isobaric yield ratio (IYR) is used to determine the temperature of heavy fragments. Cross sections of measured fragment in reactions are analyzed, and a modified statistical abrasion-ablation (SAA) model is used to calculate the yield of fragment in 140$A$ MeV $^{64}$Ni + $^{9}$Be and 1$A$ GeV $^{136}$Xe + $^{208}$Pb reactions. Relatively low $T$ of heavy fragments are obtained in different reactions ($T$ ranges from 1 to 3MeV). $T$ is also found to depend on the neutron-richness of the projectile. The incident energy affects $T$ very little. $\\Delta\\mu/T$ (the ratio of the difference between the chemical potential of neutron and proton to temperature) is found to increase linearly as $N/Z$ of projectile increases. It is found that $T$ of the $^{48}$Ca reaction, for which IYRs are of $Atemperature-corrected $\\Delta B(T)$. But $T$ of reactions using IYRs of heavier fragments are only slightly affected by the temperature-corrected $\\Delta B(T)$. The SAA model analysis gives a consistent overview of the results extracted in this work. $T$ from IYR, which is for secondary fragment, is different from that of the hot emitting source. $T$ and $\\Delta\\mu$ are essentially governed by the sequential decay process.

  20. Spreading widths of isobaric analog states and the isovector giant monopole resonance

    NASA Astrophysics Data System (ADS)

    Jänecke, J.; Harakeh, M. N.; van der Werf, S. Y.

    1987-02-01

    A global analysis of the experimental spreading widths ? ? of 65 isobaric analog states (IAS) in the range A = 110 to 238 has been performed assuming isospin mixing via the Coulomb force with T< = T0-1 doorway states mediated by coupling to the ( T0-1)-component of the giant isovector monopole resonance (IVM). Excellent agreement has been achieved over the entire range, thus establishing general smooth trends for the parameters describing the resonance. The excitation energy of the resonance, E( IVM)?V 0/A {1}/{3}-(T 0+1)V 1/A was found to reproduce the IAS data with V0 in the range 155 to 170 MeV and V1?55 MeV. These values are taken from recent theoretical estimates of Auerbach and the extreme hydrodynamical estimate of Bohr, Damgaard and Mottelson. The charge-dependent matrix elements were found factors of two to three stronger than hydrodynamic or microscopic estimates, but in almost perfect agreement with an expression based on sum rules derived by Lane and Mekjian. A strength-function approach developed by MacDonald and Birse for the damping widths of isovector monopole resonances was successfully employed. However, it became necessary to introduce an explicit dependence on nuclear deformation to describe a splitting of the IVM strength due to coupling to the ?-vibration component of the isovector quadrupole resonance (IVQ). The postulated ?-dependence describes the strong increase with neutron excess of the spreading widths for several rare-earth nuclei, and an essentially one-parameter fit to all experimental spreading widths gives ? 2/? ? 1.2 . It is further concluded that the density of doorway states which are responsible for the isospin mixing is much lower than the density of all underlying states of lower isospin with the same spin and parity as the IAS, and the ratio decreases exponentially with increasing excitation energy.

  1. Equilibrium Chemical Engines

    E-print Network

    Tatsuo Shibata; Shin-ichi Sasa

    1997-10-30

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  2. On quantum microcanonical equilibrium

    E-print Network

    Dorje C. Brody; Daniel W. Hook; Lane P. Hughston

    2006-12-14

    A quantum microcanonical postulate is proposed as a basis for the equilibrium properties of small quantum systems. Expressions for the corresponding density of states are derived, and are used to establish the existence of phase transitions for finite quantum systems. A grand microcanonical ensemble is introduced, which can be used to obtain new rigorous results in quantum statistical mechanics.

  3. Deviation from secular equilibrium

    E-print Network

    A. V. Simakin; G. A. Shafeev

    2010-01-20

    Laser exposure of gold nanoparticles in aqueous solutions of Uranium salt leads to accelerated decay of U238 nuclei and significant deviation from secular equilibrium. The samples demonstrate the enhanced gamma emission in the range of 54 keV during laser exposure.

  4. An Updated Equilibrium Machine

    ERIC Educational Resources Information Center

    Schultz, Emeric

    2008-01-01

    A device that can demonstrate equilibrium, kinetic, and thermodynamic concepts is described. The device consists of a leaf blower attached to a plastic container divided into two chambers by a barrier of variable size and form. Styrofoam balls can be exchanged across the barrier when the leaf blower is turned on and various air pressures are…

  5. Liquid-vapor relations for the system NaCl-H2O: summary of the P-T- x surface from 300° to 500°C

    USGS Publications Warehouse

    Bischoff, J.L.; Pitzer, Kenneth S.

    1989-01-01

    Experimental data on the vapor-liquid equilibrium relations for the system NaCl-H2O were compiled and compared in order to provide an improved estimate of the P-T-x surface between 300° to 500°C, a range for which the system changes from subcritical to critical behavior. Data for the three-phase curve (halite + liquid + vapor) and the NaCl-H2O critical curve were evaluated, and the best fits for these extrema then were used to guide selection of best fit for isothermal plots for the vapor-liquid region in-between. Smoothing was carried out in an iterative procedure by replotting the best-fit data as isobars and then as isopleths, until an internally consistent set of data was obtained. The results are presented in table form that will have application to theoretical modelling and to the understanding of two-phase behavior in saline geothermal systems.

  6. An Updated Equilibrium Machine

    NASA Astrophysics Data System (ADS)

    Schultz, Emeric

    2008-08-01

    A device that can demonstrate equilibrium, kinetic, and thermodynamic concepts is described. The device consists of a leaf blower attached to a plastic container divided into two chambers by a barrier of variable size and form. Styrofoam balls can be exchanged across the barrier when the leaf blower is turned on and various air pressures are applied. Equilibrium can be approached from different distributions of balls in the container under different conditions. The Le Châtelier principle can be demonstrated. Kinetic concepts can be demonstrated by changing the nature of the barrier, either changing the height or by having various sized holes in the barrier. Thermodynamic concepts can be demonstrated by taping over some or all of the openings and restricting air flow into container on either side of the barrier.

  7. Absolute Equilibrium Entropy

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1997-01-01

    The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

  8. Covariant Equilibrium Statistical Mechanics

    E-print Network

    E. Lehmann

    2006-02-25

    A manifest covariant equilibrium statistical mechanics is constructed starting with a 8N dimensional extended phase space which is reduced to the 6N physical degrees of freedom using the Poincare-invariant constrained Hamiltonian dynamics describing the micro-dynamics of the system. The reduction of the extended phase space is initiated forcing the particles on energy shell and fixing their individual time coordinates with help of invariant time constraints. The Liouville equation and the equilibrium condition are formulated in respect to the scalar global evolution parameter which is introduced by the time fixation conditions. The applicability of the developed approach is shown for both, the perfect gas as well as the real gas. As a simple application the canonical partition integral of the monatomic perfect gas is calculated and compared with other approaches. Furthermore, thermodynamical quantities are derived. All considerations are shrinked on the classical Boltzmann gas composed of massive particles and hence quantum effects are discarded.

  9. Observation of a double isobaric analog state in the reaction /sup 209/Bi(. pi. /sup +/,. pi. /sup -/)/sup 209/At

    SciTech Connect

    Morris, C.L.; Thiessen, H.A.; Braithwaite, W.J.; Cottingame, W.B.; Greene, S.J.; Holtkamp, D.B.; Moore, I.B.; Moore, C.F.; Burleson, G.R.; Blanpied, G.S.; Daw, G.H.; Viescas, A.J.

    1980-10-13

    Pion double charge exchange has been used to populate the double isobaric analog state in /sup 209/At with use of the neutron-rich target /sup 209/Bi. The data were obtained at an energy of 292 MeV and at an angle of 5/sup 0/, as the double-charge-eschange reaction mechanism has been shown to be dominated by analog transitions under these conditions in previous work on light nuclei. The measured cross section is found to be in good agreement with semiclassical predictions by Johnson.

  10. The Isospin Admixture of The Ground State and The Properties of The Isobar Analog Resonances In Deformed Nuclei

    SciTech Connect

    Aygor, H. Ali; Maras, Ismail; Cakmak, Necla; Selam, Cevad

    2008-11-11

    Within quasiparticle random phase approximation (QRPA), Pyatov-Salamov method for the self-consistent determination of the isovector effective interaction strength parameter, restoring a broken isotopic symmetry for the nuclear part of the Hamiltonian, is used. The isospin admixtures in the ground state of the parent nucleus, and the isospin structure of the isobar analog resonance (IAR) state are investigated by including the pairing correlations between nucleons for {sup 72-80}Kr isotopes. Our results are compared with the spherical case and with other theoretical results.

  11. Gravity, Dimension, Equilibrium, & Thermodynamics

    E-print Network

    Jerome Perez

    2006-03-30

    Is it actually possible to interpret gravitation as space's property in a pure classical way. Then, we note that extended self-gravitating system equilibrium depends directly on the number of dimension of the space in which it evolves. Given those precisions, we review the principal thermodynamical knowledge in the context of classical gravity with arbitrary dimension of space. Stability analyses for bounded 3D systems, namely the Antonov instability paradigm, are then rapproched to some amazing properties of globular clusters and galaxies.

  12. Equilibrium Electroconvective Instability

    NASA Astrophysics Data System (ADS)

    Rubinstein, I.; Zaltzman, B.

    2015-03-01

    Since its prediction 15 years ago, hydrodynamic instability in concentration polarization at a charge-selective interface has been attributed to nonequilibrium electro-osmosis related to the extended space charge which develops at the limiting current. This attribution had a double basis. On the one hand, it has been recognized that neither equilibrium electro-osmosis nor bulk electroconvection can yield instability for a perfectly charge-selective solid. On the other hand, it has been shown that nonequilibrium electro-osmosis can. The first theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge selectivity for the sake of simplicity and so did the subsequent studies of various time-dependent and nonlinear features of electro-osmotic instability. In this Letter, we show that relaxing the assumption of perfect charge selectivity (tantamount to fixing the electrochemical potential of counterions in the solid) allows for the equilibrium electroconvective instability. In addition, we suggest a simple experimental test for determining the true, either equilibrium or nonequilibrium, origin of instability in concentration polarization.

  13. Structural design using equilibrium programming

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J.

    1992-01-01

    Multiple nonlinear programming methods are combined in the method of equilibrium programming. Equilibrium programming theory has been appied to problems in operations research, and in the present study it is investigated as a framework to solve structural design problems. Several existing formal methods for structural optimization are shown to actually be equilibrium programming methods. Additionally, the equilibrium programming framework is utilized to develop a new structural design method. Selected computational results are presented to demonstrate the methods.

  14. Equilibrium Versus Nonequilibrium What do we mean by the terms equilibrium, far from equilibrium, local equilibrium, etc.? It is first important

    E-print Network

    Cross, Michael

    Equilibrium Versus Nonequilibrium What do we mean by the terms equilibrium, far from equilibrium, local equilibrium, etc.? It is first important to point out that we mean more by "equilibrium" than just as "far from equilibrium". More precise terms would be "thermodynamic equilibrium" and "far from

  15. Return to Equilibrium Volker Bach

    E-print Network

    Return to Equilibrium Volker Bach #3; FB Mathematik; Universitat Mainz; D-55099 Mainz; Germany that an arbitrary initial state which is normal with respect to the equilibrium state of the uncoupled system at temperature T converges to an equilibrium state of the coupled system at the same temperature, as time tends

  16. LABORATORY I FORCES AND EQUILIBRIUM

    E-print Network

    Minnesota, University of

    LABORATORY I FORCES AND EQUILIBRIUM Lab I -1 In biological systems, most objects of interest are in or almost in equilibrium, either stationary or moving with a constant velocity. This important condition of equilibrium is the result of a balance among all of the different forces interacting with the object

  17. Comparison of two different doses of intrathecal dexmedetomidine as adjuvant with isobaric ropivacaine in lower abdominal surgery

    PubMed Central

    Singh, Atul Kumar; Singh, Yashpal; Jain, Gaurav; Verma, Ravi Kumar

    2015-01-01

    Background: To augment the subarachnoid block utility, the efficacy of newer molecules as an adjuvant is investigated constantly. Considering the favorable profile of dexmedetomidine, it could have a potential role as an adjuvant to ropivacaine. Aim: We evaluated the efficacy of two different doses of dexmedetomidine as an adjuvant to isobaric ropivacaine, intrathecally. Methods: Ninety patients scheduled for lower abdominal surgery under spinal anesthesia were randomized into three groups to receive 2.5 ml of isobaric ropivacaine (0.75%, 7.5 mg/ml) added to 5 µg (10 µg/ml) or 10 µg (20 µg/ml) of dexmedetomidine or 0.5 ml of normal saline in group A, B or C, respectively. Block characteristics were compared as a primary outcome. Statistical Analysis: One-way analysis of variance test, Fisher's exact test/Chi-square test, whichever appropriate. A P < 0.05 was considered significant. Results: Time to achieve desired block was least in group B and maximum in group C. The sensory-motor blockade remained significantly prolonged in group B compared to other groups. Hemodynamic parameters remained stable in all three groups. Conclusion: Among the investigated doses, dexmedetomidine augments the efficacy of intrathecal ropivacaine in a dose-dependent manner, without any untoward side effects. PMID:26712971

  18. Isobaric Quantification of Cerebrospinal Fluid Amyloid-? Peptides in Alzheimer's Disease: C-Terminal Truncation Relates to Early Measures of Neurodegeneration.

    PubMed

    Rogeberg, Magnus; Almdahl, Ina Selseth; Wettergreen, Marianne; Nilsson, Lars N G; Fladby, Tormod

    2015-11-01

    The amyloid beta (A?) peptide is the main constituent of the plaques characteristic of Alzheimer's disease (AD). Measurement of A?1-42 in cerebrospinal fluid (CSF) is a valuable marker in AD research, where low levels indicate AD. Although the use of immunoassays measuring A?1-38 and A?1-40 in addition to A?1-42 has increased, quantitative assays of other A? peptides remain rarely explored. We recently discovered novel A? peptides in CSF using antibodies recognizing the A? mid-domain region. Here we have developed a method using both A? N-terminal and mid-domain antibodies for immunoprecipitation in combination with isobaric labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for relative quantification of endogenous A? peptides in CSF. The developed method was used in a pilot study to produce A? peptide profiles from 38 CSF samples. Statistical comparison between CSF samples from 19 AD patients and 19 cognitively healthy controls revealed no significant differences at group level. A significant correlation was found between several larger C-terminally truncated A? peptides and protein biomarkers for neuronal damage, particularly prominent in the control group. Comparison of the isobaric quantification with immunoassays measuring A?1-38 or A?1-40 showed good correlation (r(2) = 0.84 and 0.85, respectively) between the two analysis methods. The developed method could be used to assess disease-modifying therapies directed at A? production or degradation. PMID:26452689

  19. Thermodynamic properties of supercritical n-m Lennard-Jones fluids and isochoric and isobaric heat capacity maxima and minima.

    PubMed

    Mairhofer, Jonas; Sadus, Richard J

    2013-10-21

    Molecular dynamics simulations are reported for the thermodynamic properties of n-m Lennard-Jones fluids, where n = 10 and 12, and m = 5 and 6. Results are reported for the thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound at supercritical conditions covering a wide range of fluid densities. The thermodynamic criteria for maxima?minima in the isochoric and isobaric heat capacities are identified and the simulation results are also compared with calculations from Lennard-Jones equations of state. The Johnson et al. [Mol. Phys. 78, 591 (1993)] equation of state can be used to reproduce all heat capacity phenomena reported [T. M. Yigzawe and R. J. Sadus, J. Chem. Phys. 138, 194502 (2013)] from molecular dynamics simulations for the 12-6 Lennard-Jones potential. Significantly, these calculations and molecular dynamics results for other n-m Lennard-Jones potentials support the existence of Cp minima at supercritical conditions. The values of n and m also have a significant influence on many other thermodynamic properties. PMID:24160523

  20. Phase equilibrium data for development of correlations for coal fluids

    SciTech Connect

    Robinson, R.L. Jr.; Gasem, K.A.M.; Darwish, N.A.; Raff, A.M.

    1991-02-01

    The overall objective of the authors' work is to develop accurate predictive methods for representations of vapor-liquid equilibria in systems encountered in coal-conversion processes. The objectives pursued in the present project include: (1) Measurements of binary vapor-liquid phase behavior data for selected solute gases (e.g., C{sub 2}H{sub 6}, CH{sub 4}) in a series of paraffinic, naphthenic, and aromatic hydrocarbon solvents to permit evaluations of interaction parameters in models for phase behavior. Solubilities of the gases in the liquid phase have been determined. (2) Evaluation of existing equations of state and other models for representations of phase behavior in systems of the type studied experimentally; development of new correlation frameworks as needed. (3) Generalization of the interaction parameters for the solutes studied to a wide spectrum of heavy solvents; presentation of final results in formats useful in the design/optimization of coal liquefaction processes.

  1. Statistical physics ""Beyond equilibrium

    SciTech Connect

    Ecke, Robert E

    2009-01-01

    The scientific challenges of the 21st century will increasingly involve competing interactions, geometric frustration, spatial and temporal intrinsic inhomogeneity, nanoscale structures, and interactions spanning many scales. We will focus on a broad class of emerging problems that will require new tools in non-equilibrium statistical physics and that will find application in new material functionality, in predicting complex spatial dynamics, and in understanding novel states of matter. Our work will encompass materials under extreme conditions involving elastic/plastic deformation, competing interactions, intrinsic inhomogeneity, frustration in condensed matter systems, scaling phenomena in disordered materials from glasses to granular matter, quantum chemistry applied to nano-scale materials, soft-matter materials, and spatio-temporal properties of both ordinary and complex fluids.

  2. Polarized deuteron charge-exchange reaction $dp->{pp}_sN\\pi$ in the Delta-isobar region

    E-print Network

    Uzikov, Yu N; Wilkin, C

    2015-01-01

    Mechanisms of the charge exchange reaction $dp\\to \\{pp\\}_{\\!s} N\\pi$, where $\\{pp\\}_{\\!s}$ is a two-proton system at low excitation energy, are studied at beam energies 1 -- 2 GeV and for invariant masses $M_X$ of the final $N\\pi $ system that correspond to the formation of the $\\Delta(1232)$ isobar. The direct mechanism, where the initial proton is excited into the $\\Delta(1232)$, dominates and explains the existing data on the unpolarized differential cross section and spherical tensor analyzing power $T_{22}$ for $M_X> 1.2$ GeV/$c^2$. However, this model fails to describe $T_{20}.

  3. Polarized deuteron charge-exchange reaction $dp->{pp}_sN?$ in the Delta-isobar region

    E-print Network

    Yu. N. Uzikov; J. Haidenbauer; C. Wilkin

    2015-02-16

    Mechanisms of the charge exchange reaction $dp\\to \\{pp\\}_{\\!s} N\\pi$, where $\\{pp\\}_{\\!s}$ is a two-proton system at low excitation energy, are studied at beam energies 1 -- 2 GeV and for invariant masses $M_X$ of the final $N\\pi $ system that correspond to the formation of the $\\Delta(1232)$ isobar. The direct mechanism, where the initial proton is excited into the $\\Delta(1232)$, dominates and explains the existing data on the unpolarized differential cross section and spherical tensor analyzing power $T_{22}$ for $M_X> 1.2$ GeV/$c^2$. However, this model fails to describe $T_{20}.

  4. Isospin dependence of isobaric ratio Y(3H)/Y(3He) and its relation to temperature

    E-print Network

    M. Veselsky; R. W. Ibbotson; R. Laforest; E. Ramakrishnan; D. J. Rowland; A. Ruangma; E. M. Winchester; E. Martin; S. J. Yennello

    2000-11-15

    A dependence of the isobaric ratio Y(3H)/Y(3He) on the N/Z ratio of the reconstructed quasiprojectile for the reaction of 28Si beam with 112,124Sn targets at two different projectile energies 30 and 50 MeV/nucleon is presented. We demonstrate a linear dependence of ln(Y(3H)/Y(3He)) on the quasiprojectile N/Z ratio and show the dependence of the slope on reconstructed excitation energy of the quasiprojectile. We relate this slope dependence at a given excitation energy to the temperature of the fragmenting system. Using the model assumptions of the statistical multifragmentation model, a method of temperature determination is proposed. A caloric curve is constructed and compared to the result of double isotope ratio method for the same set of data and to the results of other studies.

  5. Spectroscopy of the neutron-deficient isobars {sup 163}Re and {sup 163}W using tagging techniques

    SciTech Connect

    Joss, D. T.; Thomson, J.; Page, R. D.; Bianco, L.; Darby, I. G.; Grahn, T.; Pakarinen, J.; Paul, E. S.; Scholey, C.; Eeckhaudt, S.; Greenlees, P. T.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Leppaennen, A.-P.; Nyman, M.; Rahkila, P.; Sorri, J.

    2008-11-11

    Selective tagging techniques have been used to establish new band structures in the transitional isobars {sup 163}Re and {sup 163}W. These nuclei were produced in the {sup 106}Cd({sup 60}Ni, xp yn {gamma}) reaction at a bombarding energy of 270 MeV. Prompt {gamma} rays were detected at the target position using the JUROGAM spectrometer while recoiling ions were separated by the RITU separator and implanted into the GREAT spectrometer. At low spin, the yrast band of {sup 163}Re is shown to be a strongly coupled collective band based on a proton h{sub 11/2} configuration. In {sup 163}W, the decay path of the 13/2{sup +} isomeric state to the ground state has been identified and negative parity structures based on the ground state established.

  6. Proteomic Identification and Quantification of S-glutathionylation in Mouse Macrophages Using Resin-Assisted Enrichment and Isobaric Labeling

    SciTech Connect

    Su, Dian; Gaffrey, Matthew J.; Guo, Jia; Hatchell, Kayla E.; Chu, Rosalie K.; Clauss, Therese RW; Aldrich, Joshua T.; Wu, Si; Purvine, Samuel O.; Camp, David G.; Smith, Richard D.; Thrall, Brian D.; Qian, Weijun

    2014-02-11

    Protein S-glutathionylation (SSG) is an important regulatory posttranslational modification of protein cysteine (Cys) thiol redox switches, yet the role of specific cysteine residues as targets of modification is poorly understood. We report a novel quantitative mass spectrometry (MS)-based proteomic method for site-specific identification and quantification of S-glutathionylation across different conditions. Briefly, this approach consists of initial blocking of free thiols by alkylation, selective reduction of glutathionylated thiols and enrichment using thiol affinity resins, followed by on-resin tryptic digestion and isobaric labeling with iTRAQ (isobaric tags for relative and absolute quantitation) for MS-based identification and quantification. The overall approach was validated by application to RAW 264.7 mouse macrophages treated with different doses of diamide to induce glutathionylation. A total of 1071 Cys-sites from 690 proteins were identified in response to diamide treatment, with ~90% of the sites displaying >2-fold increases in SSG-modification compared to controls.. This approach was extended to identify potential SSG modified Cys-sites in response to H2O2, an endogenous oxidant produced by activated macrophages and many pathophysiological stimuli. The results revealed 364 Cys-sites from 265 proteins that were sensitive to S-glutathionylation in response to H2O2 treatment. These proteins covered a range of molecular types and molecular functions with free radical scavenging, and cell death and survival included as the most significantly enriched functional categories. Overall the results demonstrate that our approach is effective for site-specific identification and quantification of S-glutathionylated proteins. The analytical strategy also provides a unique approach to determining the major pathways and cell processes most susceptible to glutathionylation at a proteome-wide scale.

  7. Experimental vapor-liquid equilibria in the CO/sub 2/-diethylene glycol-H/sub 2/O and CO/sub 2/-triethylene glycol-H/sub 2/O systems at feasible absorption temperatures and pressures

    SciTech Connect

    Takahashi, S.; Kobayashi, R.; Song, K.Y.

    1984-01-01

    The water contents of compressed carbon dioxide gas in equilibrium with diethylene glycol (DEG) solutions of 3.5 and 7.0 wt % water, and with triethylene glycol (TEG) solutions of the same concentrations, have been measured at temperatures of 23.89, 37.78, and 48.89 /sup 0/C, and pressures of 2.5166, 2.8955, and 5.2745 MPa. A comparison of the dehydration capabilities of the same glycol-water solution for CO/sub 2/ with that for natural gas (or methane) indicates that the dehydration qualities for the former (CO/sub 2/) exceed those for the latter on an absolute water content basis until a reversal occurs when the CO/sub 2/-rich phase begins to assume dense-fluid characteristics. The solubilities of carbon dioxide in the aqueous glycol solutions of the same concentrations and conditions as the water content measurements, and in the pure glycols, are also reported. The CO/sub 2/ solubility in TEG and DEG solutions has been analyzed thermodynamically by applying the Krichevsky-Kasarnovsky (KK) equation to both the glycol solutions and the pure glycols. The thermodynamically predicted data agreed with the experimental or smoothed experimental data to better than 2% for both the pure and aqueous solvents at temperatures ranging from 23.89 to 48.89 /sup 0/C. In the prediction, the experimental data and thermodynamically consistent low-pressure solubility data were used. Data were extrapolated to essentially zero pressure to deduce the isothermal Henry's law constants.

  8. Kinetic equilibrium and relativistic thermodynamics

    E-print Network

    P. Ván

    2011-02-01

    Relativistic thermodynamics is treated from the point of view of kinetic theory. It is shown that the generalized J\\"uttner distribution suggested in [1] is compatible with kinetic equilibrium. The requirement of compatibility of kinetic and thermodynamic equilibrium reveals several generalizations of the Gibbs relation where the velocity field is an independent thermodynamic variable.

  9. Rapid-Equilibrium Enzyme Kinetics

    ERIC Educational Resources Information Center

    Alberty, Robert A.

    2008-01-01

    Rapid-equilibrium rate equations for enzyme-catalyzed reactions are especially useful because if experimental data can be fit by these simpler rate equations, the Michaelis constants can be interpreted as equilibrium constants. However, for some reactions it is necessary to use the more complicated steady-state rate equations. Thermodynamics is…

  10. Napoleon Is in Equilibrium

    NASA Astrophysics Data System (ADS)

    Phillips, Rob

    2015-03-01

    It has been said that the cell is the test tube of the twenty-first century. If so, the theoretical tools needed to quantitatively and predictively describe what goes on in such test tubes lag sorely behind the stunning experimental advances in biology seen in the decades since the molecular biology revolution began. Perhaps surprisingly, one of the theoretical tools that has been used with great success on problems ranging from how cells communicate with their environment and each other to the nature of the organization of proteins and lipids within the cell membrane is statistical mechanics. A knee-jerk reaction to the use of statistical mechanics in the description of cellular processes is that living organisms are so far from equilibrium that one has no business even thinking about it. But such reactions are probably too hasty given that there are many regimes in which, because of a separation of timescales, for example, such an approach can be a useful first step. In this article, we explore the power of statistical mechanical thinking in the biological setting, with special emphasis on cell signaling and regulation. We show how such models are used to make predictions and describe some recent experiments designed to test them. We also consider the limits of such models based on the relative timescales of the processes of interest.

  11. Convective quasi-equilibrium

    NASA Astrophysics Data System (ADS)

    Yano, J.-I.; Plant, R. S.

    2012-12-01

    The concept of convective quasi-equilibrium (CQE) is a key ingredient in order to understand the role of deep moist convection in the atmosphere. It has been used as a guiding principle to develop almost all convective parameterizations and provides a basic theoretical framework for large-scale tropical dynamics. The CQE concept as originally proposed by Arakawa and Schubert (1974) is systematically reviewed from wider perspectives. Various interpretations and extensions of Arakawa and Schubert's CQE are considered both in terms of a thermodynamic analogy and as a dynamical balance. The thermodynamic interpretations can be more emphatically embraced as a homeostasis. The dynamic balance interpretations can be best understood by analogy with the slow manifold. Various criticisms of CQE can be avoided by taking the dynamic balance interpretation. Possible limits of CQE are also discussed, including the importance of triggering in many convective situations, as well as the possible self-organized criticality of tropical convection. However, the most intriguing aspect of the CQE concept is that in spite of many observational tests supporting and interpreting it in many different senses, it has never been established in a robust manner based on a systematic analysis of the cloud work function budget by observations as was originally defined.

  12. Equilibrium Shape of Colloidal Crystals.

    PubMed

    Sehgal, Ray M; Maroudas, Dimitrios

    2015-10-27

    Assembling colloidal particles into highly ordered configurations, such as photonic crystals, has significant potential for enabling a broad range of new technologies. Facilitating the nucleation of colloidal crystals and developing successful crystal growth strategies require a fundamental understanding of the equilibrium structure and morphology of small colloidal assemblies. Here, we report the results of a novel computational approach to determine the equilibrium shape of assemblies of colloidal particles that interact via an experimentally validated pair potential. While the well-known Wulff construction can accurately capture the equilibrium shape of large colloidal assemblies, containing [Formula: see text](10(4)) or more particles, determining the equilibrium shape of small colloidal assemblies of [Formula: see text](10) particles requires a generalized Wulff construction technique which we have developed for a proper description of equilibrium structure and morphology of small crystals. We identify and characterize fully several "magic" clusters which are significantly more stable than other similarly sized clusters. PMID:26439330

  13. Week12: Chapter 12 Static Equilibrium

    E-print Network

    1 Week12: Chapter 12 Static Equilibrium and Elasticity Static Equilibrium Equilibrium implies equilibrium is a common situation in engineering Principles involved are of particular interest to civil Conditions for Equilibrium The net force equals zero If the object is modeled as a particle

  14. Equilibrium and Non-Equilibrium Dust Cluster Modes

    SciTech Connect

    Melzer, Andre; Ivanov, Yuriy; Wolter, Matthias

    2005-10-31

    Simulations of the melting transition of 2D clusters are presented. Equilibrium melting is obtained by increasing the kinetic temperature of the dust particles. Non-equilibrium melting occurs when an additional particle is placed in a layer below the cluster plane. The presence of the lower particle drives the transition by the onset of unstable oscillations. The mode spectra of the two melting processes allow detailed insight into the governing mechanisms.

  15. Colloidal Gels: Equilibrium and Non-Equilibrium Routes

    E-print Network

    Emanuela Zaccarelli

    2007-06-12

    We attempt a classification of different colloidal gels based on colloid-colloid interactions. We discriminate primarily between non-equilibrium and equilibrium routes to gelation, the former case being slaved to thermodynamic phase separation while the latter is individuated in the framework of competing interactions and of patchy colloids. Emphasis is put on recent numerical simulations of colloidal gelation and their connection to experiments. Finally we underline typical signatures of different gel types, to be looked in more details in experiments.

  16. AUCTION EQUILIBRIUM WITH COSTLY INFORMATION ACQUISITION

    E-print Network

    Kolstad, Charles

    AUCTION EQUILIBRIUM WITH COSTLY INFORMATION ACQUISITION Rolando M. Guzman and Charles D. Kolstad* Revised Version: May 1999 ABSTRACT This paper presents a simple model of auction equilibrium conjectures regarding the behavior of other bidders. A rational expectations equilibrium is characterized

  17. Equilibrium Selection via Travelling Waves Josef Hofbauer

    E-print Network

    Hofbauer, Josef

    Equilibrium Selection via Travelling Waves the other equilibrium. This different * *evolution was made possible by an `iron curton' separating the two becomes possible.* * What will happen to the equilibria chosen. Which equilibrium will survive

  18. Equilibrium and Orientation in Cephalopods.

    ERIC Educational Resources Information Center

    Budelmann, Bernd-Ulrich

    1980-01-01

    Describes the structure of the equilibrium receptor system in cephalopods, comparing it to the vertebrate counterpart--the vestibular system. Relates the evolution of this complex system to the competition of cephalopods with fishes. (CS)

  19. NUMERICAL VERIFICATION OF EQUILIBRIUM CHEMISTRY

    SciTech Connect

    Piro, Markus; Lewis, Brent; Thompson, Dr. William T.; Simunovic, Srdjan; Besmann, Theodore M

    2010-01-01

    A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.

  20. Heft 237 Klaus Philipp Nuske Beyond Local Equilibrium --

    E-print Network

    Cirpka, Olaf Arie

    Heft 237 Klaus Philipp Nuske Beyond Local Equilibrium -- Relaxing local equilibrium assumptions in multiphase flow in porous media #12;#12;Beyond Local Equilibrium ------ Relaxing local equilibrium;#12;Heft 237 Beyond Local Equilibrium ---- Relaxing local equilibrium assumptions in multiphase flow

  1. Edge equilibrium code for tokamaks

    SciTech Connect

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids.

  2. The kinetic chemical equilibrium regime

    NASA Astrophysics Data System (ADS)

    Ern, Alexandre; Giovangigli, Vincent

    We investigate reactive gas mixtures in the kinetic chemical equilibrium regime. Our starting point is a generalized Boltzmann equation with a chemical source term valid for arbitrary reaction mechanisms and yielding a positive entropy production. We first study the Enskog expansion in the kinetic chemical equilibrium regime. We derive a new set of macroscopic equations in the zeroth- and first-order regimes, expressing conservation of element densities, momentum and energy. The transport fluxes arising in the Navier-Stokes equilibrium regime are the element diffusion velocities, the heat flux vector and the pressure tensor and are written in terms of transport coefficients. Upon introducing species diffusion velocities, the kinetic equilibrium regime appears to be formally equivalent to the one obtained for gas mixtures in chemical nonequilibrium and then letting the chemical reactions approach equilibrium. The actual values of the transport coefficients are, however, different. Finally, we derive the entropy conservation equation in the Navier-Stokes equilibrium regime and show that the source term is positive and that it is compatible with Onsager’s reciprocal relations.

  3. Differential proteomic analysis of cancer stem cell properties in hepatocellular carcinomas by isobaric tag labeling and mass spectrometry.

    PubMed

    Ko, Ching-Huai; Cheng, Chieh-Fang; Lai, Chin-Pen; Tzu, Te-Hui; Chiu, Chih-Wei; Lin, Mei-Wei; Wu, Si-Yuan; Sun, Chung-Yuan; Tseng, Hsiang-Wen; Wang, Chun-Chung; Kuo, Zong-Keng; Wang, Ling-Mei; Chen, Sung-Fang

    2013-08-01

    Malignant tumors are relatively resistant to treatment due to their heterogeneous nature, drug resistance, and tendency for metastasis. Recent studies suggest that a subpopulation of cancer cells is responsible for the malignant outcomes. These cells are considered as cancer stem cells (CSC). Although a number of molecules have been identified in different cancer cells as markers for cancer stem cells, no promising markers are currently available for hepatocellular carcinoma cells. In this study, two clones of Hep3B cell lines were functionally characterized as control or CSC-like cells, based on properties including spheroid formation, drug resistance, and tumor initiation. Furthermore, their protein expression profiles were investigated by isobaric tags for relative and absolute quantitation (iTRAQ), and a total of 1,127 proteins were identified and quantified from the combined fractions; 50 proteins exhibited at least 2-fold differences between these two clones. These 50 proteins were analyzed by GeneGo and were found to be associated with liver neoplasms, hepatocellular carcinoma (HCC), and liver diseases. They were also components of metabolic pathways, immune responses, and cytoskeleton remodeling. Among these proteins, the expressions of S100P, S100A14, and vimentin were verified in several HCC cell lines, and their expressions were correlated with tumorigenicity in HCC cell lines. The functional significance of vimentin and S100A14 were also investigated and verified. PMID:23782096

  4. Folding model study of the isobaric analog excitation: isovector density dependence, Lane potential and nuclear symmetry energy

    E-print Network

    Dao T. Khoa; Hoang Sy Than; Do Cong Cuong

    2007-06-09

    A consistent folding model analysis of the ($\\Delta S=0, \\Delta T=1$) charge exchange \\pn reaction measured with $^{48}$Ca, $^{90}$Zr, $^{120}$Sn and $^{208}$Pb targets at the proton energies of 35 and 45 MeV is done within a two-channel coupling formalism. The nuclear ground state densities given by the Hartree-Fock-Bogoljubov formalism and the density dependent CDM3Y6 interaction were used as inputs for the folding calculation of the nucleon optical potential and \\pn form factor. To have an accurate isospin dependence of the interaction, a complex isovector density dependence of the CDM3Y6 interaction has been carefully calibrated against the microscopic Brueckner-Hatree-Fock calculation by Jeukenne, Lejeune and Mahaux before being used as folding input. Since the isovector coupling was used to explicitly link the isovector part of the nucleon optical potential to the cross section of \\pn reaction exciting the 0$^+$ isobaric analog states in $^{48}$Sc, $^{90}$Nb, $^{120}$Sb and $^{208}$Bi, the newly parameterized isovector density dependence could be well tested in the folding model analysis of the \\pn reaction. The isospin- and density dependent CDM3Y6 interaction was further used in the Hartree-Fock calculation of asymmetric nuclear matter, and a realistic estimation of the nuclear symmetry energy has been made.

  5. Re-examination of Finite-Size Effects in Isobaric Yield Ratios Using a Statistical Abrasion-Ablation Model

    NASA Astrophysics Data System (ADS)

    Ma, Chun-Wang; Wang, Shan-Shan; Wei, Hui-Ling; Ma, Yu-Gang

    2013-05-01

    The “finite-size" effects in the isobaric yield ratio (IYR), which are shown in the standard grand-canonical and canonical statistical ensembles (SGC/CSE) method, are claimed to prevent the actual values of physical parameters from being obtained. The conclusion of SGC/CSE may be questionable for neutron-rich nucleus-induced reactions. To investigate whether the IYR has finite-size effects, we re-examine the IYR for the mirror nuclei [IYR(m)] using a modified statistical abrasion-ablation (SAA) model. It is found that when the projectile is not so neutron-rich, the IYR(m) depends on the isospin of the projectile, but size dependence can not be excluded. In reactions induced by the very neutron-rich projectiles, contrary results to those of the SGC/CSE models are obtained, i.e., the dependence of the IYR(m) on the size and the isospin of the projectile is weakened and disappears in both the SAA and experimental results.

  6. Dose-dependent effect of intrathecal dexmedetomidine on isobaric ropivacaine in spinal anesthesia for abdominal hysterectomy: Effect on block characteristics and hemodynamics

    PubMed Central

    Naithani, Udita; Meena, Mahendra Singh; Gupta, Sunanda; Meena, Khemraj; Swain, Lalatendu; Pradeep, D. S.

    2015-01-01

    Background and Aims: Effect of intrathecal dexmedetomidine as an adjuvant to isobaric ropivacaine in spinal anesthesia for abdominal hysterectomy is not much investigated. The objective was to assess the dose dependent effect of dexmedetomidine (3 mcg vs 5 mcg) as an adjunct to isobaric ropivacaine in spinal anesthesia. Materials and Methods: Forty selected female patients were randomized to receive intrathecal 0.5% isobaric ropivacaine (15 mg) with dexmedetomidine 3 mcg (Group D3) or 5 mcg (Group D5) in spinal anesthesia for abdominal hysterectomy. Block characteristics, hemodynamic changes, postoperative analgesia, and adverse effects were compared. Results: Both groups were comparable regarding sensory-motor block characteristics and postoperative analgesia (P > 0.05). Four (10%) patients of Group D5 and 5 (12.5%) of Group D3 could not achieve desired T6 sensory level and Bromage score of 3(complete motor block) hence were converted to general anesthesia at the outset. Nine (22.5%) patients each in both groups required ketamine supplementation (0.5 mg/kg) for intraoperative pain at the time of uterine manipulation. Incidence of hypotension was comparable (55.56% in Group D5 and 37.14% in Group D3, P = 0.11), but this occurred significantly earlier in Group D5, P < 0.001. Sedation was also significantly more in Group D5 as compared with Group D3, P < 0.01. Conclusion: We conclude that spinal anesthesia with isobaric ropivacaine (15 mg) with dexmedetomidine (3 mcg or 5 mcg) did not show much promise for abdominal hysterectomy as one third cases required analgesic supplementation. Both doses of dexmedetomidine produced a similar effect on block characteristic and postoperative analgesia; however, a dose of 5 mcg dose was associated with more hypotension and sedation. PMID:25788777

  7. The application of "double isolation" in Fourier transform ion cyclotron resonance sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry to remove labile isobaric impurities.

    PubMed

    Gates, Paul J; Lopes, Norberto P; Pinto, Emani; Colepicolo, Pio; Cardozo, Karina H M

    2011-01-01

    This study reports the application of "double isolation" in sustained off-resonance irradiation collisionally-induced dissociation tandem mass spectrometry (SORI-CID-MS/MS) to remove radio- frequency (RF) fragment ions of very close mass isobaric ions (0.02 m/z apart). Analyses were performed with a fraction of a biological extract isolated from a macroalgae containing the mycosporine-like amino acid asterina-330. Direct isolation of the precursor ion by narrowing the isolation window proved ineffective as it impinged upon the required ion thus substantially reducing its intensity. By increasing the correlated sweep time, ejection efficiency of the isolation was improved, but caused the unwanted side-effect of RF fragmentation of labile ions. Finally, by skipping the ion activation step and performing a second isolation (in the MS(3) module) the RF fragments from the first isolation were removed leaving a very pure isolation of the required precursor ion and allowed a very clean CID fragmentation. We demonstrated that the m/z 272.1351 ion is derived from the loss of NH(3) from m/z 289.1620 isobaric impurity and is not related to asterina-330. This application represents a powerful tool to remove unwanted ions in the MS/MS spectrum that result from fragmentation of isobaric ions. PMID:22173541

  8. Fluid-solid equilibrium of carbon dioxide as obtained from computer simulations of several popular potential models: the role of the quadrupole.

    PubMed

    Pérez-Sánchez, G; González-Salgado, D; Piñeiro, M M; Vega, C

    2013-02-28

    In this work the solid-fluid equilibrium for carbon dioxide (CO2) has been evaluated using Monte Carlo simulations. In particular the melting curve of the solid phase denoted as I, or dry ice, was computed for pressures up to 1000 MPa. Four different models, widely used in computer simulations of CO2 were considered in the calculations. All of them are rigid non-polarizable models consisting of three Lennard-Jones interaction sites located on the positions of the atoms of the molecule, plus three partial charges. It will be shown that although these models predict similar vapor-liquid equilibria their predictions for the fluid-solid equilibria are quite different. Thus the prediction of the entire phase diagram is a severe test for any potential model. It has been found that the Transferable Potentials for Phase Equilibria (TraPPE) model yields the best description of the triple point properties and melting curve of carbon dioxide. It is shown that the ability of a certain model to predict the melting curve of carbon dioxide is related to the value of the quadrupole moment of the model. Models with low quadrupole moment tend to yield melting temperatures too low, whereas the model with the highest quadrupole moment yields the best predictions. That reinforces the idea that not only is the quadrupole needed to provide a reasonable description of the properties in the fluid phase, but also it is absolutely necessary to describe the properties of the solid phase. PMID:23464159

  9. Fluid-solid equilibrium of carbon dioxide as obtained from computer simulations of several popular potential models: The role of the quadrupole

    NASA Astrophysics Data System (ADS)

    Pérez-Sánchez, G.; González-Salgado, D.; Piñeiro, M. M.; Vega, C.

    2013-02-01

    In this work the solid-fluid equilibrium for carbon dioxide (CO2) has been evaluated using Monte Carlo simulations. In particular the melting curve of the solid phase denoted as I, or dry ice, was computed for pressures up to 1000 MPa. Four different models, widely used in computer simulations of CO2 were considered in the calculations. All of them are rigid non-polarizable models consisting of three Lennard-Jones interaction sites located on the positions of the atoms of the molecule, plus three partial charges. It will be shown that although these models predict similar vapor-liquid equilibria their predictions for the fluid-solid equilibria are quite different. Thus the prediction of the entire phase diagram is a severe test for any potential model. It has been found that the Transferable Potentials for Phase Equilibria (TraPPE) model yields the best description of the triple point properties and melting curve of carbon dioxide. It is shown that the ability of a certain model to predict the melting curve of carbon dioxide is related to the value of the quadrupole moment of the model. Models with low quadrupole moment tend to yield melting temperatures too low, whereas the model with the highest quadrupole moment yields the best predictions. That reinforces the idea that not only is the quadrupole needed to provide a reasonable description of the properties in the fluid phase, but also it is absolutely necessary to describe the properties of the solid phase.

  10. Tuning universality far from equilibrium

    PubMed Central

    Karl, Markus; Nowak, Boris; Gasenzer, Thomas

    2013-01-01

    Possible universal dynamics of a many-body system far from thermal equilibrium are explored. A focus is set on meta-stable non-thermal states exhibiting critical properties such as self-similarity and independence of the details of how the respective state has been reached. It is proposed that universal dynamics far from equilibrium can be tuned to exhibit a dynamical transition where these critical properties change qualitatively. This is demonstrated for the case of a superfluid two-component Bose gas exhibiting different types of long-lived but non-thermal critical order. Scaling exponents controlled by the ratio of experimentally tuneable coupling parameters offer themselves as natural smoking guns. The results shed light on the wealth of universal phenomena expected to exist in the far-from-equilibrium realm. PMID:23928853

  11. Adiabatic evolution of plasma equilibrium

    PubMed Central

    Grad, H.; Hu, P. N.; Stevens, D. C.

    1975-01-01

    A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included. PMID:16578729

  12. Neutron-skin effects in isobaric yield ratio for mirror nuclei in statistical abrasion-ablation model

    E-print Network

    Chunwang Ma; Huiling Wei; Yugang Ma

    2013-10-16

    \\item[Purpose] We suppose that the IYR(m) depends on the neutron-skin thickness ($\\delta_{np}$) of the projectile, and check the idea of whether the neutron-skin thickness effects can fully explain the systematic dependence of the IYR(m). \\item[Methods] A modified statistical abrasion-ablation model is used to calculate the reactions induced by projectiles of three series. \\item[Results] The IYR(m) shows a distribution of a linear part in the small-$x$ fragments, and a nonlinear part in the large-$x$ fragments. The linear part of IYR(m) is fitted. (1) In the calcium isotopic reactions, the IYR(m) depends on the isospin or the volume of the projectile, but $\\delta_{np}$ greatly influences the nonlinear part of the IYR(m). The IYR(m) does not depend on the colliding source in reactions of small $b_{\\mbox{max}}$ for the nonneutron-rich projectiles, and does not depend on the collision sources in reactions by the neutron-rich projectiles; (2) In reactions of the $A = 45$ isobars, though IYR(m) depends on the isospin of projectile, IYR(m) shows small dependence on isospin if $\\delta_{np} > 0$; (3) In the reactions of projectiles having similar $\\delta_{np}$, the IYR(m) in the small mass fragments show no dependence on the volume and the isospin of the projectile when the mass of the projectile is relatively large. Specially, the dependence of IYR(m) on the mass of the isospin of the projectile vanishes when $\\delta_{np}\\sim0.02$fm. \\item[Conclusions] The linear and nonlinear parts of the IYR(m) are governed by the core and the surface (skin) of the projectile, respectively. The neutron-skin effects can well explain the systematic dependence of the IYR(m).

  13. High-field asymmetric-waveform ion mobility spectrometry and electron detachment dissociation of isobaric mixtures of glycosaminoglycans.

    PubMed

    Kailemia, Muchena J; Park, Melvin; Kaplan, Desmond A; Venot, Andre; Boons, Geert-Jan; Li, Lingyun; Linhardt, Robert J; Amster, I Jonathan

    2014-02-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is shown to be capable of resolving isomeric and isobaric glycosaminoglycan negative ions and to have great utility for the analysis of this class of molecules when combined with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tandem mass spectrometry. Electron detachment dissociation (EDD) and other ion activation methods for tandem mass spectrometry can be used to determine the sites of labile sulfate modifications and for assigning the stereochemistry of hexuronic acid residues of glycosaminoglycans (GAGs). However, mixtures with overlapping mass-to-charge values present a challenge, as their precursor species cannot be resolved by a mass analyzer prior to ion activation. FAIMS is shown to resolve two types of mass-to-charge overlaps. A mixture of chondroitin sulfate A (CSA) oligomers with 4-10 saccharides units produces ions of a single mass-to-charge by electrospray ionization, as the charge state increases in direct proportion to the degree of polymerization for these sulfated carbohydrates. FAIMS is shown to resolve the overlapping charge. A more challenging type of mass-to-charge overlap occurs for mixtures of diastereomers. FAIMS is shown to separate two sets of epimeric GAG tetramers. For the epimer pairs, the complexity of the separation is reduced when the reducing end is alkylated, suggesting that anomers are also resolved by FAIMS. The resolved components were activated by EDD and the fragment ions were analyzed by FTICR-MS. The resulting tandem mass spectra were able to distinguish the two epimers from each other. PMID:24254578

  14. High-Field Asymmetric-Waveform Ion Mobility Spectrometry and Electron Detachment Dissociation of Isobaric Mixtures of Glycosaminoglycans

    PubMed Central

    Kailemia, Muchena J.; Park, Melvin; Kaplan, Desmond A.; Venot, Andre; Boons, Geert-Jan; Li, Lingyun; Linhardt, Robert J.; Amster, I. Jonathan

    2014-01-01

    High-field asymmetric waveform ion mobility spectrometry (FAIMS) is shown to be capable of resolving isomeric and isobaric glycosaminoglycan negative ions, and to have great utility for the analysis of this class of molecules when combined with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) and tandem mass spectrometry. Electron detachment dissociation (EDD) and other ion activation methods for tandem mass spectrometry can be used to determine the sites of labile sulfate modifications and for assigning the stereochemistry of hexuronic acid residues of GAGs. However, mixtures with overlapping mass-to-charge values present a challenge, as their precursor species cannot be resolved by a mass analyzer prior to ion activation. FAIMS is shown to resolve two types of mass-to-charge overlaps. A mixture of chondroitin sulfate A (CSA) oligomers with 4–10 saccharides units produces ions of a single mass-to-charge by electrospray ionization, as the charge state increases in direct proportion to the degree of polymerization for these sulfated carbohydrates. FAIMS is shown to resolve the overlapping charge. A more challenging type of mass-to-charge overlap occurs for mixtures of diastereomers. FAIMS is shown to separate two sets of epimeric GAG tetramers. For the epimer pairs, the complexity of the separation is reduced when the reducing end is alkylated, suggesting that anomers are also resolved by FAIMS. The resolved components were activated by EDD and the fragment ions were analyzed by FTICR-MS. The resulting tandem mass spectra were able to distinguish the two epimers from each other. PMID:24254578

  15. Chiral approach to nuclear matter: Role of two-pion exchange with virtual delta-isobar excitation

    E-print Network

    S. Fritsch; N. Kaiser; W. Weise

    2004-10-05

    We extend a recent three-loop calculation of nuclear matter in chiral perturbation theory by including the effects from two-pion exchange with single and double virtual $\\Delta(1232)$-isobar excitation. Regularization dependent short-range contributions from pion-loops are encoded in a few NN-contact coupling constants. The empirical saturation point of isospin-symmetric nuclear matter, $\\bar E_0 = -16 $MeV, $\\rho_0 = 0.16 $fm$^{-3}$, can be well reproduced by adjusting the strength of a two-body term linear in density (and weakening an emerging three-body term quadratic in density). The nuclear matter compressibility comes out as $K = 304 $MeV. The real single-particle potential $U(p,k_{f0})$ is substantially improved by the inclusion of the chiral $\\pi N\\Delta$-dynamics: it grows now monotonically with the nucleon momentum $p$. The effective nucleon mass at the Fermi surface takes on a realistic value of $M^*(k_{f0})=0.88M$. As a consequence of these features, the critical temperature of the liquid-gas phase transition gets lowered to the value $T_c \\simeq 15 $MeV. In this work we continue the complex-valued single-particle potential $U(p,k_f)+i W(p,k_f)$ into the region above the Fermi surface $p>k_f$. The effects of $2\\pi$-exchange with virtual $\\Delta$-excitation on the nuclear energy density functional are also investigated. The effective nucleon mass associated with the kinetic energy density is $\\widetilde M^*(\\rho_0)= 0.64M$. Furthermore, we find that the isospin properties of nuclear matter get significantly improved by including the chiral $\\pi N\\Delta$-dynamics.

  16. A Quantitative Tool to Distinguish Isobaric Leucine and Isoleucine Residues for Mass Spectrometry-Based De Novo Monoclonal Antibody Sequencing

    NASA Astrophysics Data System (ADS)

    Poston, Chloe N.; Higgs, Richard E.; You, Jinsam; Gelfanova, Valentina; Hale, John E.; Knierman, Michael D.; Siegel, Robert; Gutierrez, Jesus A.

    2014-07-01

    De novo sequencing by mass spectrometry (MS) allows for the determination of the complete amino acid (AA) sequence of a given protein based on the mass difference of detected ions from MS/MS fragmentation spectra. The technique relies on obtaining specific masses that can be attributed to characteristic theoretical masses of AAs. A major limitation of de novo sequencing by MS is the inability to distinguish between the isobaric residues leucine (Leu) and isoleucine (Ile). Incorrect identification of Ile as Leu or vice versa often results in loss of activity in recombinant antibodies. This functional ambiguity is commonly resolved with costly and time-consuming AA mutation and peptide sequencing experiments. Here, we describe a set of orthogonal biochemical protocols, which experimentally determine the identity of Ile or Leu residues in monoclonal antibodies (mAb) based on the selectivity that leucine aminopeptidase shows for n-terminal Leu residues and the cleavage preference for Leu by chymotrypsin. The resulting observations are combined with germline frequencies and incorporated into a logistic regression model, called Predictor for Xle Sites (PXleS) to provide a statistical likelihood for the identity of Leu at an ambiguous site. We demonstrate that PXleS can generate a probability for an Xle site in mAbs with 96% accuracy. The implementation of PXleS precludes the expression of several possible sequences and, therefore, reduces the overall time and resources required to go from spectra generation to a biologically active sequence for a mAb when an Ile or Leu residue is in question.

  17. High precision Pu isotope ratios using MC-ICPMS equipped with collision-cell technology to suppress U isobaric interferences

    NASA Astrophysics Data System (ADS)

    Granet, M.; Isnard, H.; Nonell, A.; Quidelleur, S.; Chartier, F.

    2009-04-01

    The measurement of Pu isotope ratios is of prime interest in both the environmental and nuclear research fields. First, new chronometric tracers need to be developed in order to understand and quantify the mechanisms and time-scales controlling the landscape evolution since it gives informations on climatic variations. Additionally, the analysis of Pu isotopes after irradiation of 235U is required in the transmutation field in order to determine basic neutronic data such as cross sections and reaction rates. High precision isotope ratios measurements are usually performed with sector field mass spectrometers, either by Thermal Ionization Mass Spectrometry (TIMS) or by Multiple Collection Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). One of the major drawbacks in analysing Pu isotopes is the occurrence of U isobaric interferences: 238U-238Pu and 238UH+-239Pu. Here we propose to suppress these interferences by adding reactive gases in the collision-reaction cell of the MC-ICP-MS (Isoprobe, GV Instruments, Manchester, UK). The difference of reactivity for U and Pu towards these gases allows the measurement of Pu isotopes with precision and accuracy similar to those obtained after a previous chemical separation of Pu from U using anion-exchange resin. This study thus confirms that collision-reaction cells are powerful tools to perform isotopic measurements of soils, river sediments or irradiated materials without former systematic chemical separations as U interferences are completely removed in situ. References Granet et al. (2008), Spectrochimica Acta Part B 63, 1309-1314. Moureau et al. (2008), JAAS 23, 1538-1544.

  18. Magnetospheric equilibrium with anisotropic pressure

    SciTech Connect

    Cheng, C.Z.

    1991-07-01

    Self-consistent magnetospheric equilibrium with anisotropic pressure is obtained by employing an iterative metric method for solving the inverse equilibrium equation in an optimal flux coordinate system. A method of determining plasma parallel and perpendicular pressures from either analytic particle distribution or particle distribution measured along the satellite's path is presented. The numerical results of axisymmetric magnetospheric equilibrium including the effects of finite beta, pressure anisotropy, and boundary conditions are presented for a bi-Maxwellian particle distribution. For the isotropic pressure cases, the finite beta effect produces an outward expansion of the constant magnetic flux surfaces in relation to the dipole field lines, and along the magnetic field the toroidal ring current is maximum at the magnetic equator. The effect of pressure anisotropy is found to further expand the flux surfaces outward. Along the magnetic field lines the westward ring current can be peak away from the equator due to an eastward current contribution resulting from pressure anisotropy. As pressure anisotropy increases, the peak westward current can become more singular. The outer boundary flux surface has significant effect on the magnetospheric equilibrium. For the outer flux boundary resembling dayside compressed flux surface due to solar wind pressure, the deformation of the magnetic field can be quite different from that for the outer flux boundary resembling the tail-like surface. 23 refs., 17 figs.

  19. Quantifying mixing using equilibrium reactions

    SciTech Connect

    Wheat, Philip M.; Posner, Jonathan D.

    2009-03-15

    A method of quantifying equilibrium reactions in a microchannel using a fluorometric reaction of Fluo-4 and Ca{sup 2+} ions is presented. Under the proper conditions, equilibrium reactions can be used to quantify fluid mixing without the challenges associated with constituent mixing measures such as limited imaging spatial resolution and viewing angle coupled with three-dimensional structure. Quantitative measurements of CaCl and calcium-indicating fluorescent dye Fluo-4 mixing are measured in Y-shaped microchannels. Reactant and product concentration distributions are modeled using Green's function solutions and a numerical solution to the advection-diffusion equation. Equilibrium reactions provide for an unambiguous, quantitative measure of mixing when the reactant concentrations are greater than 100 times their dissociation constant and the diffusivities are equal. At lower concentrations and for dissimilar diffusivities, the area averaged fluorescence signal reaches a maximum before the species have interdiffused, suggesting that reactant concentrations and diffusivities must be carefully selected to provide unambiguous, quantitative mixing measures. Fluorometric equilibrium reactions work over a wide range of pH and background concentrations such that they can be used for a wide variety of fluid mixing measures including industrial or microscale flows.

  20. Equilibrium Thermodynamics of Lattice QCD

    E-print Network

    D. K. Sinclair

    2007-02-03

    Lattice QCD allows us to simulate QCD at non-zero temperature and/or densities. Such equilibrium thermodynamics calculations are relevant to the physics of relativistic heavy-ion collisions. I give a brief review of the field with emphasis on our work.

  1. Thermodynamic theory of equilibrium fluctuations

    NASA Astrophysics Data System (ADS)

    Mishin, Y.

    2015-12-01

    The postulational basis of classical thermodynamics has been expanded to incorporate equilibrium fluctuations. The main additional elements of the proposed thermodynamic theory are the concept of quasi-equilibrium states, a definition of non-equilibrium entropy, a fundamental equation of state in the entropy representation, and a fluctuation postulate describing the probability distribution of macroscopic parameters of an isolated system. Although these elements introduce a statistical component that does not exist in classical thermodynamics, the logical structure of the theory is different from that of statistical mechanics and represents an expanded version of thermodynamics. Based on this theory, we present a regular procedure for calculations of equilibrium fluctuations of extensive parameters, intensive parameters and densities in systems with any number of fluctuating parameters. The proposed fluctuation formalism is demonstrated by four applications: (1) derivation of the complete set of fluctuation relations for a simple fluid in three different ensembles; (2) fluctuations in finite-reservoir systems interpolating between the canonical and micro-canonical ensembles; (3) derivation of fluctuation relations for excess properties of grain boundaries in binary solid solutions, and (4) derivation of the grain boundary width distribution for pre-melted grain boundaries in alloys. The last two applications offer an efficient fluctuation-based approach to calculations of interface excess properties and extraction of the disjoining potential in pre-melted grain boundaries. Possible future extensions of the theory are outlined.

  2. Understanding Thermal Equilibrium through Activities

    ERIC Educational Resources Information Center

    Pathare, Shirish; Huli, Saurabhee; Nachane, Madhura; Ladage, Savita; Pradhan, Hemachandra

    2015-01-01

    Thermal equilibrium is a basic concept in thermodynamics. In India, this concept is generally introduced at the first year of undergraduate education in physics and chemistry. In our earlier studies (Pathare and Pradhan 2011 "Proc. episteme-4 Int. Conf. to Review Research on Science Technology and Mathematics Education" pp 169-72) we…

  3. Two-Step Vapor/Liquid/Solid Purification

    NASA Technical Reports Server (NTRS)

    Holland, L. R.

    1986-01-01

    Vertical distillation system combines in single operation advantages of multiple zone refining with those of distillation. Developed specifically to load Bridgman-Stockbarger (vertical-solidification) growth ampoules with ultrapure tellurium and cadmium, system, with suitable modifications, serves as material refiner. In first phase of purification process, ampoule heated to drive off absorbed volatiles. Second phase, evaporator heated to drive off volatiles in charge. Third phase, slowly descending heater causes distillation from evaporator to growing crystal in ampoule.

  4. Catalytic hydrogenation process and apparatus with improved vapor liquid separation

    DOEpatents

    Chervenak, Michael C. (Pennington, NJ); Comolli, Alfred G. (Trenton, NJ)

    1980-01-01

    A continuous hydrogenation process and apparatus wherein liquids are contacted with hydrogen in an ebullated catalyst reaction zone with the liquids and gas flowing vertically upwardly through that zone into a second zone substantially free of catalyst particles and wherein the liquid and gases are directed against an upwardly inclining surface through which vertical conduits are placed having inlet ends at different levels in the liquid and having outlet ends at different levels above the inclined surface, such that vapor-rich liquid is collected and discharged through conduits terminating at a higher level above the inclined surface than the vapor-poor liquid which is collected and discharged at a level lower than the inclined surface.

  5. Non-Equilibrium Properties from Equilibrium Free Energy Calculations

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Wilson, Michael A.

    2012-01-01

    Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.

  6. Measurement and isobar-model analysis of the doubly differential cross section for the. pi. /sup +/ produced in. pi. /sup -/p. -->. pi. /sup +/. pi. /sup -/n

    SciTech Connect

    Manley, D.M.

    1981-11-01

    The doubly differential cross section d/sup 2/sigma/d..cap omega..dT for ..pi../sup +/ mesons produced in the reaction ..pi../sup -/p ..-->.. ..pi../sup +/..pi../sup -/n was measured at 203, 230, 256, and 358 MeV with a single-arm magnetic spectrometer. A set of five previous measurements at 254, 280, 292, 331, and 356 MeV was reanalyzed with the new measurements. Integrated cross sections were calculated for the combined data set with unprecedented accuracy for this energy range. The chiral-symmetry-breaking parameter was determined to be epsilon = -0.03 +- 0.26 by extrapolating the mean square modulus of the matrix element to threshold and comparing the threshold matrix element with the prediction of soft-pion theory. This value of epsilon is consistent with zero as required by the Weinberg Lagrangian. Measurements at the three highest energies were compared with the results of an isobar-model analysis of bubble-chamber events by an LBL-SLAC collaboration. After allowing for an overall normalization difference, the measurements at 331 and 358 MeV were in excellent agreement with the results of their analysis. The measurement at 292 MeV required variation of the PS11(epsilonN) amplitude, as well as the overall normalization, which could be due to the limited number of bubble-chamber events available for the LBL-SLAC analysis at this energy. A partial-wave analysis of the measurements was also carried out with the VPI isobar model. Within this model, the matrix element contains a background term calculated from a phenomenological ..pi..N Lagrangian that is consistent with the hypotheses of current algebra and PCAC. The reaction was found to be dominated by the initial P11 wave. Production of the ..delta.. isobar from initial D waves was found to be significant at the two highest energies.

  7. Rare evidence for formation of garnet + corundum during isobaric cooling of ultrahigh temperature metapelites: New insights for retrograde P-T trajectory of the Highland Complex, Sri Lanka

    NASA Astrophysics Data System (ADS)

    Dharmapriya, P. L.; Malaviarachchi, Sanjeeva P. K.; Galli, Andrea; Su, Ben-Xun; Subasinghe, N. D.; Dissanayake, C. B.

    2015-04-01

    We report the occurrence of coexisting garnet + corundum in spinel- and corundum-bearing, garnet-sillimanite-biotite-graphite gneiss (pelitic granulites) from the Highland Complex (HC), Sri Lanka. In the investigated pelitic granulites, two domains such as quartz-saturated and quartz-undersaturated are distinguishable. The quartz-saturated domains consist of porphyroblastic garnet, quartz, plagioclase, alkali-feldspar and biotite flakes rimming garnet. The quartz-undersaturated domains are constituted of two generations of garnet (Grt1 and Grt2), sillimanite, plagioclase, alkali-feldspar, corundum, spinel and biotite. Grt1 encloses rare Ti-rich biotite and numerous rutile needles and apatite rods. Grt2 contains rare sillimanite and/or spinel inclusions. Corundum occurs in mutual contact with Grt2, partially embedded at the rim or as an inclusions in Grt2. Thermobarometry on inclusion phases in Grt1 indicates that during the prograde history pelitic granulites attained a P of 10.5-11 kbar at T of ~ 850 °C. Textural observations coupled with both pseudosections calculated in the NCKFMASHTMnO system and Ti-in-Garnet geothermobarometry suggest that peak metamorphism occurred at ultrahigh temperature (UHT) conditions of 950-975 °C and pressures of 9-9.5 kbar. Peak T was followed by a period of isobaric cooling that formed corundum and Grt2 at approx. 930 °C along with exsolution of rutile needles and apatite rods in Grt1. Thermodynamic modelling confirms that corundum appears along an isobaric cooling path at about 920-930 °C and 9-9.5 kbar. Therefore, the investigated granulites provide a rare example of post-peak crystallization of garnet + corundum along a retrograde metamorphic trajectory under UHT conditions. Thus, isobaric cooling at the base of the crust could be regarded as an alternative process to form coexisting garnet + corundum.

  8. Isobar separation of 93Zr and 93Nb at 24 MeV with a new multi-anode ionization chamber

    NASA Astrophysics Data System (ADS)

    Martschini, Martin; Buchriegler, Josef; Collon, Philippe; Kutschera, Walter; Lachner, Johannes; Lu, Wenting; Priller, Alfred; Steier, Peter; Golser, Robin

    2015-10-01

    93Zr with a half-life of 1.6 Ma is produced with high yield in nuclear fission, and thus should be present as a natural or anthropogenic trace isotope in all compartments of the general environment. Sensitive measurements of this isotope would immediately find numerous applications, however, its detection at sufficiently low levels has not yet been achieved. AMS measurements of 93Zr suffer from the interference of the stable isobar 93Nb. At the Vienna Environmental Research Accelerator VERA a new multi-anode ionization chamber was built. It is optimized for isobar separation in the medium mass range and is based on the experience from AMS experiments of 36Cl at our 3-MV tandem accelerator facility. The design provides high flexibility in anode configuration and detector geometry. After validating the excellent energy resolution of the detector with 36S, it was recently used to study iron-nickel and zirconium-niobium-molybdenum isobar separation. To our surprise, the separation of 94Zr (Z = 40) from 94Mo (Z = 42) was found to be much better than that of 58Fe (Z = 26) from 58Ni (Z = 28), despite the significantly larger ?Z/Z of the latter pair. This clearly contradicts results from SRIM-simulations and suggests that differences in the stopping behavior may unexpectedly favor identification of 93Zr. At 24 MeV particle energy, a 93Nb (Z = 41) suppression factor of 1000 is expected based on a synthetic 93Zr spectrum obtained by interpolation between experimental spectra from the two neighboring stable isotopes 92Zr and 94Zr. Assuming realistic numbers for chemical niobium reduction, a detection level of 93Zr/Zr below 10-9 seems feasible.

  9. A comparison of thoracic spinal anesthesia with low-dose isobaric and low-dose hyperbaric bupivacaine for orthopedic surgery: A randomized controlled trial

    PubMed Central

    Imbelloni, Luiz Eduardo; Gouveia, Marildo A.

    2014-01-01

    Background: The thoracic spinal anesthesia was first described in 1909 and recently revised for various surgical procedures. This is a prospective study aims to evaluate the parameters of the thoracic spinal anesthesia (latency, motor block and paresthesia), the incidence of cardiovascular changes and complications comparing low doses of isobaric and hyperbaric bupivacaine. Materials and Methods: A total of 200 orthopedic patients operated under spinal anesthesia were included in this study. Spinal anesthesia was between T9-T10, with a 27G cutting point or pencil tip in lateral or sitting. Spinal anesthesia was performed with 0.5% bupivacaine isobaric or hyperbaric. Patients remained in cephalad or head down position 10-20° for 10 minutes. We evaluated the demographics, analgesia, and degree of motor block, incidence of paresthesia, bradycardia, hypotension, anesthesia success and neurological complications. Results: All patients developed spinal and there was no failure. The solution did not affect the onset of the blockade. The duration of motor block was greater than the sensitive with isobaric. The duration of sensory block was greater than the motor block with hyperbaric solution. The incidence of paresthesia was 4%, with no difference between the needles. The incidence of hypotension was 12.5% with no difference between the solutions. There was no neurological damage in all patients. Conclusion: The beginning of the block is fast regardless of the solution used. By providing a sensory block of longer duration than the motor block hyperbaric bupivacaine is reflected in a better indication. Thoracic spinal anesthesia provides excellent anesthesia for lower limb orthopedic surgery PMID:25886099

  10. Simultaneous quantification of protein phosphorylation sites using liquid chromatography-tandem mass spectrometry-based targeted proteomics: a linear algebra approach for isobaric phosphopeptides.

    PubMed

    Xu, Feifei; Yang, Ting; Sheng, Yuan; Zhong, Ting; Yang, Mi; Chen, Yun

    2014-12-01

    As one of the most studied post-translational modifications (PTM), protein phosphorylation plays an essential role in almost all cellular processes. Current methods are able to predict and determine thousands of phosphorylation sites, whereas stoichiometric quantification of these sites is still challenging. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS)-based targeted proteomics is emerging as a promising technique for site-specific quantification of protein phosphorylation using proteolytic peptides as surrogates of proteins. However, several issues may limit its application, one of which relates to the phosphopeptides with different phosphorylation sites and the same mass (i.e., isobaric phosphopeptides). While employment of site-specific product ions allows for these isobaric phosphopeptides to be distinguished and quantified, site-specific product ions are often absent or weak in tandem mass spectra. In this study, linear algebra algorithms were employed as an add-on to targeted proteomics to retrieve information on individual phosphopeptides from their common spectra. To achieve this simultaneous quantification, a LC-MS/MS-based targeted proteomics assay was first developed and validated for each phosphopeptide. Given the slope and intercept of calibration curves of phosphopeptides in each transition, linear algebraic equations were developed. Using a series of mock mixtures prepared with varying concentrations of each phosphopeptide, the reliability of the approach to quantify isobaric phosphopeptides containing multiple phosphorylation sites (? 2) was discussed. Finally, we applied this approach to determine the phosphorylation stoichiometry of heat shock protein 27 (HSP27) at Ser78 and Ser82 in breast cancer cells and tissue samples. PMID:25403019

  11. Vadose zone isobaric well

    DOEpatents

    Hubbell, Joel M. (Idaho Falls, ID); Sisson, James B. (Idaho Falls, ID)

    2001-01-01

    A deep tensiometer is configured with an outer guide tube having a vented interval along a perforate section at its lower end, which is isolated from atmospheric pressure at or above grade. A transducer having a monitoring port and a reference port is located within a coaxial inner guide tube. The reference port of the transducer is open to the vented interval of the outer guide tube, which has the same gas pressure as in the sediment surrounding the tensiometer. The reference side of the pressure transducer is thus isolated from the effects of atmospheric pressure changes and relative to pressure changes in the material surrounding the tensiometer measurement location and so it is automatically compensated for such pressure changes.

  12. Evidence for a breakdown of the Isobaric Multiplet Mass Equation: A study of the A=35, T=3/2 isospin quartet

    E-print Network

    C. Yazidjian; G. Audi; D. Beck; K. Blaum; S. George; C. Guenaut; F. Herfurth; A. Herlert; A. Kellerbauer; H. -J. Kluge; D. Lunney; L. Schweikhard

    2007-07-21

    Mass measurements on radionuclides along the potassium isotope chain have been performed with the ISOLTRAP Penning trap mass spectrometer. For 35K T1/2=178ms) to 46K (T1/2=105s) relative mass uncertainties of 2x10-8 and better have been achieved. The accurate mass determination of 35K (dm=0.54keV) has been exploited to test the Isobaric Multiplet Mass Equation (IMME) for the A=35, T=3/2 isospinquartet. The experimental results indicate a deviation from the generally adopted quadratic form.

  13. Possible change in the collision frequency in the lower ionosphere with an increase of the height of isobaric surfaces in the stratosphere

    NASA Astrophysics Data System (ADS)

    Starovatov, A. A.; Boltenko, V. D.; Kalmykova, E. V.

    1988-02-01

    The paper presents an analysis of midday-absorption values according to the A1 method for Rostov-on-Don for 1970-1982, Ashkhabad for 1973-1977, and Alma-Ata for 1971-1977 as a function of the 10-hPa isobaric surface height for magnetically quiet conditions. It is shown that a negative dependence of absorption on geopotential with a simultaneous increase of electron density in the D and E regions is possible only in the case of a nonlinear increase in the collision frequency.

  14. Thermal Equilibrium Calorimeters -- An Introduction

    E-print Network

    Dan McCammon

    2005-03-07

    Near-equilibrium thermal detectors operate as classical calorimeters, with energy deposition and internal equilibration times short compared to the thermal time constant of the device. Advances in fabrication techniques, cryogenics, and electronics have made it practical to measure deposited energy with unprecedented sensitivity and precision. In this chapter we discuss performance considerations for these devices, including optimal filtering and energy resolution calculations. We begin with the basic theory of simple equilibrium calorimeters with ideal resistive thermometers. This provides a starting point for a brief discussion of electrothermal feedback, other noise sources, various non-ideal effects, and nonlinearity. We then describe other types of thermometers and show how they fit into this theoretical framework and why they may require different optimizations and figures of merit. Most of this discussion is applicable also to power detectors, or bolometers, where the detector time constants may be short compared to variations in the incident signal power.

  15. Non-equilibrium steady states

    NASA Astrophysics Data System (ADS)

    Nicolas, J.

    2002-11-01

    This paper deals with some thermodynamical aspects of a class of models in non equilibrium quantum statistical mechanics (QSM) which are commonly used to describe the behaviour of infinite quantum systems perturbed by a time-dependent periodic force. We are interested to the thermodynamical properties of the set of non-equilibrium steady states (NESS) of the perturbed system. We extend the construction of the C-Liouvillean originally introduce in [1] to our time-dependent situation to define the C-Liouvillean of Floquet KF. The NESS are thus described by zero-resonance eigenvectors of KF*. We also give a time dependent version of the rate of entropy production [2] for the perturbed system based on the relative entropy as defined by Araki [3] in terms of the relative modular operator.

  16. Thermodynamic equilibrium at heterogeneous pressure

    NASA Astrophysics Data System (ADS)

    Vrijmoed, J. C.; Podladchikov, Y. Y.

    2015-07-01

    Recent advances in metamorphic petrology point out the importance of grain-scale pressure variations in high-temperature metamorphic rocks. Pressure derived from chemical zonation using unconventional geobarometry based on equal chemical potentials fits mechanically feasible pressure variations. Here, a thermodynamic equilibrium method is presented that predicts chemical zoning as a result of pressure variations by Gibbs energy minimization. Equilibrium thermodynamic prediction of the chemical zoning in the case of pressure heterogeneity is done by constrained Gibbs minimization using linear programming techniques. In addition to constraining the system composition, a certain proportion of the system is constrained at a specified pressure. Input pressure variations need to be discretized, and each discrete pressure defines an additional constraint for the minimization. The Gibbs minimization method provides identical results to a geobarometry approach based on chemical potentials, thus validating the inferred pressure gradient. The thermodynamic consistency of the calculation is supported by the similar result obtained from two different approaches. In addition, the method can be used for multi-component, multi-phase systems of which several applications are given. A good fit to natural observations in multi-phase, multi-component systems demonstrates the possibility to explain phase assemblages and zoning by spatial pressure variations at equilibrium as an alternative to pressure variation in time due to disequilibrium.

  17. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

    Glaese, J. R.; Kennel, H. F.

    1979-01-01

    All the available torque equilibrium attitudes (most were useless from the standpoint of lack of electrical power) and the equilibrium seeking method are presented, as well as the actual successful application during the 3 weeks prior to Skylab reentry.

  18. Reflective equilibrium and the 'moral conservatism' objection 

    E-print Network

    Chandler, James Robert

    2002-01-01

    Reflective equilibrium is widely accepted as a method of justifying ethical beliefs. Narrow reflective equilibrium justifies moral beliefs by achieving coherence between moral principles and moral judgments. However, this theory has been accused...

  19. Accelerating Multiagent Reinforcement Learning by Equilibrium Transfer.

    PubMed

    Hu, Yujing; Gao, Yang; An, Bo

    2015-07-01

    An important approach in multiagent reinforcement learning (MARL) is equilibrium-based MARL, which adopts equilibrium solution concepts in game theory and requires agents to play equilibrium strategies at each state. However, most existing equilibrium-based MARL algorithms cannot scale due to a large number of computationally expensive equilibrium computations (e.g., computing Nash equilibria is PPAD-hard) during learning. For the first time, this paper finds that during the learning process of equilibrium-based MARL, the one-shot games corresponding to each state's successive visits often have the same or similar equilibria (for some states more than 90% of games corresponding to successive visits have similar equilibria). Inspired by this observation, this paper proposes to use equilibrium transfer to accelerate equilibrium-based MARL. The key idea of equilibrium transfer is to reuse previously computed equilibria when each agent has a small incentive to deviate. By introducing transfer loss and transfer condition, a novel framework called equilibrium transfer-based MARL is proposed. We prove that although equilibrium transfer brings transfer loss, equilibrium-based MARL algorithms can still converge to an equilibrium policy under certain assumptions. Experimental results in widely used benchmarks (e.g., grid world game, soccer game, and wall game) show that the proposed framework: 1) not only significantly accelerates equilibrium-based MARL (up to 96.7% reduction in learning time), but also achieves higher average rewards than algorithms without equilibrium transfer and 2) scales significantly better than algorithms without equilibrium transfer when the state/action space grows and the number of agents increases. PMID:25181517

  20. Morphodynamic equilibrium of alluvial estuaries

    NASA Astrophysics Data System (ADS)

    Tambroni, Nicoletta; Bolla Pittaluga, Michele; Canestrelli, Alberto; Lanzoni, Stefano; Seminara, Giovanni

    2014-05-01

    The evolution of the longitudinal bed profile of an estuary, with given plan-form configuration, subject to given tidal forcing at the mouth and prescribed values of water and sediment supply from the river is investigated numerically. Our main goal is to ascertain whether, starting from some initial condition, the bed evolution tends to reach a unique equilibrium configuration asymptotically in time. Also, we investigate the morphological response of an alluvial estuary to changes in the tidal range and hydrologic forcing (flow and sediment supply). Finally, the solution helps characterizing the transition between the fluvially dominated region and the tidally dominated region of the estuary. All these issues play an important role also in interpreting how the facies changes along the estuary, thus helping to make correct paleo-environmental and sequence-stratigraphic interpretations of sedimentary successions (Dalrymple and Choi, 2007). Results show that the model is able to describe a wide class of settings ranging from tidally dominated estuaries to fluvially dominated estuaries. In the latter case, the solution is found to compare satisfactory with the analytical asymptotic solution recently derived by Seminara et al. (2012), under the hypothesis of fairly 'small' tidal oscillations. Simulations indicate that the system always moves toward an equilibrium configuration in which the net sediment flux in a tidal cycle is constant throughout the estuary and equal to the constant sediment flux discharged from the river. For constant width, the bed equilibrium profile of the estuarine channel is characterized by two distinct regions: a steeper reach seaward, dominated by the tide, and a less steep upstream reach, dominated by the river and characterized by the undisturbed bed slope. Although the latter reach, at equilibrium, is not directly affected by the tidal wave, however starting from an initial uniform stream with the constant 'fluvial' slope, the final equilibrium state is reached through an erosional wave, which leads to bed degradation of the upstream 'fluvial reach'. For a given river discharge, the length of the tidal reach increases quite rapidly with tidal amplitude, up to some threshold value of the tidal amplitude above which the length of the estuary becomes comparable with the length of the tidal wave. When the channel plan-form is convergent, deposition of sediments of fluvial origin in the funnel-shaped region drastically changes the equilibrium configuration. The effect of an increasing channel convergence is thus to induce bed aggradation close to the inlet. Nevertheless, tidal forcing only slightly changes the non-tidal profile. The effect of increasing tidal oscillations again leads to an increase of the bed slope at the inlet and to a general bed degradation upstream. The effects of varying sediment supply, flow discharge and river width in the upstream reach have also been investigated and play an important role. Further geomorphological implications of these results will be discussed at the meeting. References Dalrymple, R. W., and K. Choi (2007), Morphologic and facies trends through the fluvialmarine transition in tide-dominated depositional systems: A schematic framework for environmental and sequence-stratigraphic interpretation, Earth-Science Reviews, 81(3-4), 135-174, doi:10.1016/j.earscirev.2006.10.002. Seminara, G., M. Bolla Pittaluga, and N. Tambroni (2012), Morphodynamic equilibrium of tidal channels, Environmental Fluid Mechanics: Memorial Volume in Honour of Prof. Gerhard H. Jirka, 153-174

  1. NonEquilibrium Thermodynamics Explains Semiotic Shapes

    E-print Network

    Kreinovich, Vladik

    Non­Equilibrium Thermodynamics Explains Semiotic Shapes: Applications to Astronomy and to Non­equilibrium thermodynamics, non­destructive testing, aerospace structures 1. SEMIOTIC SHAPES IN ASTRONOMY: FORMULATION by using the fundamental physical ideas of symmetry and non­equilibrium thermodynamics. 2. MAIN PHYSICAL

  2. Equilibrium resource management with altruistic overlapping generations

    E-print Network

    Karp, Larry S.

    Equilibrium resource management with altruistic overlapping generations Ivar Ekeland a , Larry Karp non-constant discount rates, leading to time inconsistency. The unique Markov Perfect equilibrium, the equilibrium policy does not depend on the degree of that concern. & 2014 Elsevier Inc. All rights reserved

  3. Spheromak Equilibrium Studies on SSX Cameron Geddes

    E-print Network

    Geddes, Cameron Guy Robinson

    Spheromak Equilibrium Studies on SSX Cameron Geddes Swarthmore College Department of Physics 10 used to study the equilibrium states of magnetized toroidal plasma configurations called spheromaks the equilibrium, and shows evolution of the state over time. Results indicate a reliable equilibration

  4. Stochastic interacting particle systems out of equilibrium

    E-print Network

    Landim, Claudio

    Stochastic interacting particle systems out of equilibrium L. Bertini1 A. De Sole2 D. Gabrielli3 G models of lattice gases out of equilibrium and a discussion of results of various kinds obtained connecting the non equilibrium thermodynamics to the transport coefficients via a variational principle

  5. Equilibrium Statistical Mechanics of Network Structures

    E-print Network

    Derényi, Imre

    Equilibrium Statistical Mechanics of Network Structures Ill´es Farkas1 , Imre Der´enyi2 , Gergely give an in depth overview of the recent advances in the field of equilibrium networks. After outlining this topic, we provide a novel way of defining equilibrium graph (network) ensembles. We illustrate

  6. IMPLAUSIBLE EQUILIBRIUM SOLUTIONS IN ECONOMICS AND FINANCE

    E-print Network

    Lamba, Harbir

    IMPLAUSIBLE EQUILIBRIUM SOLUTIONS IN ECONOMICS AND FINANCE HARBIR LAMBA1 Abstract When modelling the system as always being in equilibrium -- using averaging procedures based upon assumptions of ra] suggested that allowing a subset of the agents to be non- maximizing might shift the equilibrium solution

  7. Oblivious Router Policies and Nash Equilibrium

    E-print Network

    Rey Juan Carlos, Universidad

    Oblivious Router Policies and Nash Equilibrium Juan A. Almendral, Luis L. Fern´andez, Vicent Cholvi. In such a scenario, having a Nash equilibrium guarantees that no selfish user has incentive to unilaterally deviate users). However, here we formally prove that an efficient Nash equilibrium can not be reached

  8. EQUILIBRIUM CONSTRAINED OPTIMIZATION PROBLEMS S . I. BIRBIL

    E-print Network

    Al Hanbali, Ahmad

    EQUILIBRIUM CONSTRAINED OPTIMIZATION PROBLEMS S¸ . I. BIRBIL , G. BOUZA , J.B.G. FRENK and G. STILL § July 26, 2004 ABSTRACT. We consider equilibrium constrained optimization problems, which have a general for- mulation that encompasses well-known models such as mathematical programs with equilibrium

  9. Nash Equilibrium and Dynamics Sergiu Hart

    E-print Network

    Hart, Sergiu

    Nash Equilibrium and Dynamics Sergiu Hart June 2008 Conference in Honor of John Nash's 80th Birthday Opening Panel SERGIU HART c 2008 ­ p. #12;NASH EQUILIBRIUM AND DYNAMICS Sergiu Hart Center@huji.ac.il http://www.ma.huji.ac.il/hart SERGIU HART c 2008 ­ p. #12;Nash equilibrium SERGIU HART c 2008 ­ p. #12

  10. Equilibrium Participation in Public Goods Allocations 1

    E-print Network

    Equilibrium Participation in Public Goods Allocations 1 Paul J. Healy 2 Abstract An alternative planner. The set of allocations such that unanimous participation is a Nash equilibrium is shown to be sub allow a no-trade option. The resulting constraint, called equilibrium participation, requires

  11. Boltzmann, Gibbs and the Concept of Equilibrium

    E-print Network

    Lavis, David

    Boltzmann, Gibbs and the Concept of Equilibrium David A. Lavis Abstract The Boltzmann and Gibbs approaches to statistical mechanics have very different definitions of equilibrium and entropy. The problems a version of statistical mechanics incorporating both approaches, by redefining equilibrium not as a binary

  12. Are the Concepts of Dynamic Equilibrium and the Thermodynamic Criteria for Spontaneity, Nonspontaneity, and Equilibrium Compatible?

    ERIC Educational Resources Information Center

    Silverberg, Lee J.; Raff, Lionel M.

    2015-01-01

    Thermodynamic spontaneity-equilibrium criteria require that in a single-reaction system, reactions in either the forward or reverse direction at equilibrium be nonspontaneous. Conversely, the concept of dynamic equilibrium holds that forward and reverse reactions both occur at equal rates at equilibrium to the extent allowed by kinetic…

  13. On purification of equilibrium in Bayesian games and ex-post Nash equilibrium

    E-print Network

    Stephan, Frank

    On purification of equilibrium in Bayesian games and ex-post Nash equilibrium Edward Cartwright of an ex post stable strategy vector implies the existence of an approximate Bayesian equilibrium in pure for the comments and the NUS for its support and hospitality. 1 #12;1 Ex post Nash equilibrium and purification

  14. Equilibrium The theory of equilibrium attempts to predict what happens in a game when players be-

    E-print Network

    Fiat, Amos

    Chapter 2 Equilibrium The theory of equilibrium attempts to predict what happens in a game when of equilibrium. They will all be static notions in that players are as- sumed to understand the game should look elsewhere for formal justifications. This chapter reviews equilibrium in both complete

  15. Equilibrium The theory of equilibrium attempts to predict what happens in a game

    E-print Network

    Fiat, Amos

    2 Equilibrium The theory of equilibrium attempts to predict what happens in a game when players of equilibrium. They will all be static notions in that players are assumed to understand the game and will play reviews equilibrium in both complete and incomplete information games. As games of incomplete information

  16. Custom 4-Plex DiLeu Isobaric Labels Enable Relative Quantification of Urinary Proteins in Men with Lower Urinary Tract Symptoms (LUTS)

    PubMed Central

    Greer, Tyler; Hao, Ling; Nechyporenko, Anatoliy; Lee, Sanghee; Vezina, Chad M.; Ricke, Will A.; Marker, Paul C.; Bjorling, Dale E.; Bushman, Wade; Li, Lingjun

    2015-01-01

    The relative quantification of proteins using liquid chromatography mass spectrometry (LC-MS) has allowed researchers to compile lists of potential disease markers. These complex quantitative workflows often include isobaric labeling of enzymatically-produced peptides to analyze their relative abundances across multiple samples in a single LC-MS run. Recent efforts by our lab have provided scientists with cost-effective alternatives to expensive commercial labels. Although the quantitative performance of these dimethyl leucine (DiLeu) labels has been reported using known ratios of complex protein and peptide standards, their potential in large-scale proteomics studies using a clinically relevant system has never been investigated. Our work rectifies this oversight by implementing 4-plex DiLeu to quantify proteins in the urine of aging human males who suffer from lower urinary tract symptoms (LUTS). Protein abundances in 25 LUTS and 15 control patients were compared, revealing that of the 836 proteins quantified, 50 were found to be differentially expressed (>20% change) and statistically significant (p-value <0.05). Gene ontology (GO) analysis of the differentiated proteins showed that many were involved in inflammatory responses and implicated in fibrosis. While confirmation of individual protein abundance changes would be required to verify protein expression, this study represents the first report using the custom isobaric label, 4-plex DiLeu, to quantify protein abundances in a clinically relevant system. PMID:26267142

  17. A high-performance multiple-reflection time-of-flight mass spectrometer and isobar separator for the research with exotic nuclei

    NASA Astrophysics Data System (ADS)

    Dickel, T.; Plaß, W. R.; Becker, A.; Czok, U.; Geissel, H.; Haettner, E.; Jesch, C.; Kinsel, W.; Petrick, M.; Scheidenberger, C.; Simon, A.; Yavor, M. I.

    2015-03-01

    A novel multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) and isobar separator for the research with exotic nuclides at low-energy rare isotope beam facilities has been developed, commissioned and characterized. It can be used (i) as broadband mass spectrometer with medium resolution, (ii) as highly accurate mass spectrometer for direct mass measurements and (iii) as high-resolution mass separator. The device features a worldwide unique combination of performance characteristics: a mass resolving power of 600,000 (FWHM), a mass measurement accuracy of ~10-7, large ion capacities in excess of 106 ions per second, a transmission efficiency of up to 70%, single-ion sensitivity, and cycle frequencies of up to 400 Hz have been achieved. The spatial separation of close-lying isobars with an intensity ratio of 200:1 and a binding energy difference as small as 4 MeV has been demonstrated. The MR-TOF-MS is ideally suited for experiments with rare and very short-lived nuclei at present and future in-flight, ISOL or IGISOL facilities, such as the FRS Ion-Catcher and SHIP/SHIPTRAP at GSI, TITAN at TRIUMF, IGISOL at the University of Jyväskylä and the Low-Energy Branch of the Super-FRS at FAIR.

  18. Hard spheres out of equilibrium

    NASA Astrophysics Data System (ADS)

    Hermes, M.

    2010-05-01

    In this thesis, experiments and simulations are combined to investigate the nonequilibrium behaviour of hard spheres. In the first chapters we use Molecular Dynamics simulations to investigate the dynamic glass transition of polydisperse hard spheres. We show that this dynamic transition is accompanied by a thermodynamic signature. The higher-order derivatives of the pressure change abruptly at the dynamic glass transition. If a system is compressed beyond this dynamic transition, the pressure increases until it diverges when the system is completely jammed. The density at which the pressure diverges depends on the compression speed. We proceed with experiments on colloidal polymethylmethacrylate (PMMA) particles which closely resemble hard spheres. We investigate the effect of compression using gravity and electric field gradients on the nucleation and on the glass transition. The transition from glass to crystal is gradual and is strongly effected by gravity. We go back to computer simulations to investigate two different techniques to calculate the rate at which a hard-sphere system nucleates. We find that the two techniques yield similar results for the nucleation rate as well as the critical nucleus shape. From this we conclude that the simulation techniques are valid. A combination of simulations and experiments is used to study the nucleation of hard spheres on seed structures. We initiate the nucleation with a seed of particles kept in place by optical tweezers. We show that whereas the nucleation itself can be well described as an equilibrium process, the growth after nucleation can not. We demonstrate that defects play an important role in the growth of the crystal. Colloidal hard spheres can also be driven out of equilibrium using shear. We perform experiments on an equilibrium fluid phase below the coexistence density of the fluid. We show that we can induce order in an equilibrium fluid using oscillatory shear. We find five different phases for varying frequency and amplitude: four known phases and one new phase. The formation of all phases occurs via nucleation and growth and the melting, when the shear is stopped, starts on the edges and near the defects of the crystal phases. In the final chapter, we investigate the interactions between rough colloidal particles in the presence of polymers. We investigate whether surface roughness can be used to reduce the depletion attraction. We find that when the polymer is smaller than the surface roughness the attraction can be reduced significantly compared to smooth colloids.

  19. Equilibrium Sampling in Biomolecular Simulation

    PubMed Central

    2015-01-01

    Equilibrium sampling of biomolecules remains an unmet challenge after more than 30 years of atomistic simulation. Efforts to enhance sampling capability, which are reviewed here, range from the development of new algorithms to parallelization to novel uses of hardware. Special focus is placed on classifying algorithms — most of which are underpinned by a few key ideas — in order to understand their fundamental strengths and limitations. Although algorithms have proliferated, progress resulting from novel hardware use appears to be more clear-cut than from algorithms alone, partly due to the lack of widely used sampling measures. PMID:21370970

  20. Thermal equilibrium in Einstein's elevator.

    PubMed

    Sánchez-Rey, Bernardo; Chacón-Acosta, Guillermo; Dagdug, Leonardo; Cubero, David

    2013-05-01

    We report fully relativistic molecular-dynamics simulations that verify the appearance of thermal equilibrium of a classical gas inside a uniformly accelerated container. The numerical experiments confirm that the local momentum distribution in this system is very well approximated by the Jüttner function-originally derived for a flat spacetime-via the Tolman-Ehrenfest effect. Moreover, it is shown that when the acceleration or the container size is large enough, the global momentum distribution can be described by the so-called modified Jüttner function, which was initially proposed as an alternative to the Jüttner function. PMID:23767501

  1. Far-From-Equilibrium Physics: An Overview

    E-print Network

    Heinrich M. Jaeger; Andrea J. Liu

    2010-09-24

    Isolated systems tend to evolve towards equilibrium, a special state that has been the focus of many-body research for a century. Yet much of the richness of the world around us arises from conditions far from equilibrium. Phenomena such as turbulence, earthquakes, fracture, and life itself occur only far from equilibrium. Subjecting materials to conditions far from equilibrium leads to otherwise unattainable properties. For example, rapid cooling is a key process in manufacturing the strongest metallic alloys and toughest plastics. Processes that occur far from equilibrium also create some of the most intricate structures known, from snowflakes to the highly organized structures of life. While much is understood about systems at or near equilibrium, we are just beginning to uncover the basic principles governing systems far from equilibrium.

  2. A Stochastic Algorithm for the Isobaric-Isothermal Ensemble with Ewald Summations for All Long Range Forces.

    PubMed

    Di Pierro, Michele; Elber, Ron; Leimkuhler, Benedict

    2015-12-01

    We present an algorithm termed COMPEL (COnstant Molecular Pressure with Ewald sum for Long range forces) to conduct simulations in the NPT ensemble. The algorithm combines novel features recently proposed in the literature to obtain a highly efficient and accurate numerical integrator. COMPEL exploits the concepts of molecular pressure, rapid stochastic relaxation to equilibrium, exact calculation of the contribution to the pressure of long-range nonbonded forces with Ewald summation, and the use of Trotter expansion to generate a robust, highly stable, symmetric, and accurate algorithm. Explicit implementation in the MOIL program and illustrative numerical examples are discussed. PMID:26616351

  3. The Sulfur-Iodine Cycle: Process Analysis and Design Using Comprehensive Phase Equilibrium Measurements and Modeling

    SciTech Connect

    Thies, Mark C.; O'Connell, J. P.; Gorensek, Maximilian B.

    2010-01-10

    Of the 100+ thermochemical hydrogen cycles that have been proposed, the Sulfur-Iodine (S-I) Cycle is a primary target of international interest for the centralized production of hydrogen from nuclear power. However, the cycle involves complex and highly nonideal phase behavior at extreme conditions that is only beginning to be understood and modeled for process simulation. The consequence is that current designs and efficiency projections have large uncertainties, as they are based on incomplete data that must be extrapolated from property models. This situation prevents reliable assessment of the potential viability of the system and, even more, a basis for efficient process design. The goal of this NERI award (05-006) was to generate phase-equilibrium data, property models, and comprehensive process simulations so that an accurate evaluation of the S-I Cycle could be made. Our focus was on Section III of the Cycle, where the hydrogen is produced by decomposition of hydroiodic acid (HI) in the presence of water and iodine (I2) in a reactive distillation (RD) column. The results of this project were to be transferred to the nuclear hydrogen community in the form of reliable flowsheet models for the S-I process. Many of the project objectives were achieved. At Clemson University, a unique, tantalum-based, phase-equilibrium apparatus incorporating a view cell was designed and constructed for measuring fluid-phase equilibria for mixtures of iodine, HI, and water (known as HIx) at temperatures to 350 °C and pressures to 100 bar. Such measurements were of particular interest for developing a working understanding of the expected operation of the RD column in Section III. The view cell allowed for the IR observation and discernment of vapor-liquid (VL), liquid-liquid, and liquid-liquid-vapor (LLVE) equilibria for HIx systems. For the I2-H2O system, liquid-liquid equilibrium (LLE) was discovered to exist at temperatures up to 310-315 °C, in contrast to the models and predictions of earlier workers. For the I2-HI-H2O ternary, LLE and LLVE were all observed for the first time at temperatures of 160 and 200 °C. Three LLE tie-lines were measured at 160 °C, and preliminary indications are that the underlying phase behavior could result in further improvements in the performance of the S-I Cycle. Unfortunately, these new results were obtained too late in the project to be incorporated into the modeling and simulation work described below. At the University of Virginia, a uniquely complete and reliable model was developed for the thermodynamic properties of HIx, covering the range of conditions expected for the separation of product hydrogen and recycled iodine in the RD column located in Section III. The model was validated with all available property spectroscopy data. The results provide major advances over prior understanding of the chemical speciation involved. The model was implemented in process simulation studies of the S-I Cycle, which showed improvement in energy efficiency to 42%, as well as significantly smaller capital requirements due to lower pressure operation and much smaller equipment sizes. The result is that the S-I Cycle may be much more economically feasible than was previously thought. If both the experimental and modeling work described above were to be continued to ultimate process optimization, both the American public and the global community would benefit from this alternative energy source that does not produce carbon emissions.

  4. Equilibrium sampling by re-weighting non-equilibrium simulation trajectories

    E-print Network

    Cheng Yang; Biao Wan; Shun Xu; Yanting Wang; and Xin Zhou

    2015-12-29

    With the traditional equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space in complex systems, which are separated into some metastable conformational regions by high free energy barriers. The applied non-equilibrium process in simulations could enhance the transitions among these conformational regions, and the associated non-equilibrium effects can be removed by employing the Jarzynski equality (JE), then the global equilibrium distribution can be reproduced. However, the original JE requires the initial distribution of the non-equilibrium process is equilibrium, which largely limits the application of the non-equilibrium method in equilibrium sampling. By extending the previous method, the reweighted ensemble dynamics (RED), which re-weights many equilibrium simulation trajectories from arbitrary initial distribution to reproduce the global equilibrium, to non-equilibrium simulations, we present a method, named as re-weighted non-equilibrium ensemble dynamics (RNED), to generalize the JE in the non-equilibrium trajectories started from an arbitrary initial distribution, thus provide an efficient method to reproduce the equilibrium distribution based on multiple independent (short) non-equilibrium trajectories. We have illustrated the validity of the RNED in a one-dimensional toy model and in a Lennard-Jones system to detect the liquid-solid phase coexistence.

  5. Non-equilibrium phase transitions

    SciTech Connect

    Mottola, E.; Cooper, F.M.; Bishop, A.R.; Habib, S.; Kluger, Y.; Jensen, N.G.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Non-equilibrium phase transitions play a central role in a very broad range of scientific areas, ranging from nuclear, particle, and astrophysics to condensed matter physics and the material and biological sciences. The aim of this project was to explore the path to a deeper and more fundamental understanding of the common physical principles underlying the complex real time dynamics of phase transitions. The main emphasis was on the development of general theoretical tools to deal with non-equilibrium processes, and of numerical methods robust enough to capture the time-evolving structures that occur in actual experimental situations. Specific applications to Laboratory multidivisional efforts in relativistic heavy-ion physics (transition to a new phase of nuclear matter consisting of a quark-gluon plasma) and layered high-temperature superconductors (critical currents and flux flow at the National High Magnetic Field Laboratory) were undertaken.

  6. Equilibrium calculations of firework mixtures

    SciTech Connect

    Hobbs, M.L.; Tanaka, Katsumi; Iida, Mitsuaki; Matsunaga, Takehiro

    1994-12-31

    Thermochemical equilibrium calculations have been used to calculate detonation conditions for typical firework components including three report charges, two display charges, and black powder which is used as a fuse or launch charge. Calculations were performed with a modified version of the TIGER code which allows calculations with 900 gaseous and 600 condensed product species at high pressure. The detonation calculations presented in this paper are thought to be the first report on the theoretical study of firework detonation. Measured velocities for two report charges are available and compare favorably to predicted detonation velocities. However, the measured velocities may not be true detonation velocities. Fast deflagration rather than an ideal detonation occurs when reactants contain significant amounts of slow reacting constituents such as aluminum or titanium. Despite such uncertainties in reacting pyrotechnics, the detonation calculations do show the complex nature of condensed phase formation at elevated pressures and give an upper bound for measured velocities.

  7. Equilibrium structure of ferrofluid aggregates

    SciTech Connect

    Yoon, Mina; Tomanek, David

    2010-01-01

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  8. Nonicosahedral Equilibrium Overlayers of Icosahedral Quasicrystals

    NASA Astrophysics Data System (ADS)

    Yurechko, M.; Grushko, B.; Ebert, Ph.

    2005-12-01

    We demonstrate that icosahedral Al-Pd-Mn quasicrystals can have nonicosahedrally ordered thermodynamic equilibrium overlayers. The formation of orthorhombic or decagonal equilibrium surface structures is determined by the phase equilibrium of the ternary alloy at given composition and temperature as well as by the surface acting as nucleation site. Nonequilibrium steady-state orthorhombic and hexagonal structures can also be derived with the same methodology when taking preferential evaporation into account. The results describe consistently all presently observed surface structures.

  9. Relativistic equilibrium distribution by relative entropy maximization

    NASA Astrophysics Data System (ADS)

    Nakamura, T. K.

    2009-11-01

    The equilibrium state of a relativistic gas has been calculated based on the maximum entropy principle. Though the relativistic equilibrium state was long believed to be the Jüttner distribution, a number of papers have been published in recent years proposing alternative equilibrium states. Some of these papers do not pay enough attention to the covariance of distribution functions, resulting in confusion in equilibrium states. Starting from a fully covariant expression, it has been shown in the present paper that the Jüttner distribution is the maximum entropy state if we assume the Lorentz symmetry.

  10. Passive equilibrium studies on ZT-P

    SciTech Connect

    Pickrell, M.M.; Reass, W.A.

    1987-12-01

    The poloidal field system of ZT-P was modified by the addition of a transformer, which coupled the magnetizing and equilibrium circuits. ZT-P is a small, air core, Reversed Field Pinch, operated at the Los Alamos National Laboratory. It is used as test bed for the much larger ZT-H, RFP experiment, now under construction at LANL. Planned experiments include size scaling measurements and determining the effect of low time constant measurements and determining the effect of low time constant shell operation. ZT-P has had an entirely passive equilibrium system, which did not provide a well centered equilibrium, although a tolerable equilibrium was realized by removing half of the equilibrium coil set. The transformer was added to the poloidal field system to adjust the equilibrium current for a centered plasma, while using the entire coil set. It also had the effect of reducing the dependence of the equilibrium on the plasma resistance. Stable, well centered discharges were achieved over a broad range of plasma currents. The improved equilibrium also lowered the loop voltage and extended the discharge lifetime. These experiments also investigated the unique problems of equilibrium systems on air core RFP devices. 26 refs., 6 figs.

  11. 1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO

    SciTech Connect

    T. EVANS; ET AL

    2000-08-01

    We present a new hybrid Monte Carlo method for 1-D equilibrium diffusion problems in which the radiation field coexists with matter in local thermodynamic equilibrium. This method, the Equilibrium Discrete Diffusion Monte Carlo (EqDDMC) method, combines Monte Carlo particles with spatially discrete diffusion solutions. We verify the EqDDMC method with computational results from three slab problems. The EqDDMC method represents an incremental step toward applying this hybrid methodology to non-equilibrium diffusion, where it could be simultaneously coupled to Monte Carlo transport.

  12. Determining Equilibrium Position For Acoustical Levitation

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Aveni, G.; Putterman, S.; Rudnick, J.

    1989-01-01

    Equilibrium position and orientation of acoustically-levitated weightless object determined by calibration technique on Earth. From calibration data, possible to calculate equilibrium position and orientation in presence of Earth gravitation. Sample not levitated acoustically during calibration. Technique relies on Boltzmann-Ehrenfest adiabatic-invariance principle. One converts resonant-frequency-shift data into data on normalized acoustical potential energy. Minimum of energy occurs at equilibrium point. From gradients of acoustical potential energy, one calculates acoustical restoring force or torque on objects as function of deviation from equilibrium position or orientation.

  13. First Online Mass Measurements of Isobar Chains via Multi-Reflection Time-of-Flight Mass Spectrograph Coupled with GARIS-II

    E-print Network

    P. Schury; M. Wada; Y. Ito; D. Kaji; P-A Soderstrom; A Takamine; F Arai; H. Haba; S. Jeong; S. Kimura; H. Koura; H. Miyatake; K. Morimoto; K. Morita; A. Ozawa; M. Reponen; T. Sonoda; T. Tanaka; H. Wollnik

    2015-12-01

    Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several heavy nuclei have been directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectile-like and target-like particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were observed. Precision atomic mass values were determined for 205,206Fr, 201At, and 201Po.

  14. Formation of garnet + corundum during isobaric cooling at UHT conditions: an example from pelitic granulites of the Highland Complex, Sri Lanka

    NASA Astrophysics Data System (ADS)

    Laksthitha Dharmapriya, Prasanna; Galli, Andrea; Prabath Malaviarachchi, Sanjeeva; Su, Ben-Xun

    2014-05-01

    Coexisting garnet and corundum have been reported from different rock types such as UHP rocks, aluminous eclogites, kimberlites and numerous granulites worldwide which experienced UHT conditions of 900-1050 °C at relatively high but not eclogitic pressures of 10-12 kbar. In pelitic granulites the assemblage garnet + corundum is usually interpreted to form at peak P during prograde heating along a clock-wise metamorphic path and subsequently breaks down during decompression to form sapphirine, cordierite-sapphirine-spinel or spinel-sillimanite bearing assemblages, depending on the PT-trajectory and bulk rock composition. In any cases, coexisting garnet + corundum are rarely preserved. Even less usual is the occurrence of garnet + corundum in pyroxene-free rocks. In this study, we report the occurrence of coexisting garnet + corundum within spinel- and corundum-bearing, orthopyroxene-free garnet-sillimanite-biotite-graphite gneisses from the Highland Complex (HC), Sri Lanka. In the investigated pelitic granulites, quartz-saturated domains and quartz-deficient domains are distinguishable. Quartz-saturated domains consist of quartz, plagioclase, alkali-feldspar, garnet-porphyroblasts and biotite flakes around garnet. Quartz-deficient domains are constituted of sillimanite, plagioclase, alkali-feldspar, corundum, spinel, biotite and two generations of garnet. Grt1 is coarse- to medium-grained (0.5-3 cm in diameter) and encloses rare Ti-rich biotite and numerous rutile needles and apatite rods. Grt2 is medium- to fine-grained (0.25-1 cm in diameter), contains rare sillimanite and/or spinel inclusions and is always associated with corundum. Corundum occurs in mutual contact with Grt2, partially embedded within rim area of Grt2 or as inclusions in Grt2. Rarely, tiny spinel inclusions can be observed in corundum. The chemistry of minerals preserved as inclusion in Grt1 indicates that pelitic granulites attained maximal P of 10.5-11 kbar at T around 850°C during their prograde history. Further heating induced a series of biotite-melting reactions which progressively consumed biotite and quartz from the rock matrix and produced garnet-porphyroblasts and spinel. Textural observations coupled with both pseudosections calculated in the CNKFMASHTMnO system and Ti-in-garnet geothermobarometry suggest that peak metamorphic temperature occurred at UHT conditions of 950-975 0C and pressures of 9-9.5 kbar. Peak T was followed by a period of isobaric cooling responsible for the formation of corundum and Grt2 via the reaction Spl + Sil = Grt2 + Crn at around 930 °C, as well as exsolution of rutile needles and apatite rods from Grt1. Modelling of the mode of spinel, sillimanite, corundum and garnet confirms that along an isobaric cooling path at about 920-930 °C and 9-9.5 kbar corundum appears and spinel contemporaneously disappears. At the same PT conditions, our model predicts a decrease of sillimanite and an increase of garnet content. Further isobaric cooling produced a second generation of biotite at the rim of large Grt1-porphyroblasts at ca. 800 °C. Therefore, the investigated granulites provide a rare but meaningful example where garnet + corundum formed along a retrograde metamorphic trajectory under UHT conditions, forcing to consider isobaric cooling at the base of the crust as an alternative process to explain the formation of coexisting garnet + corundum, especially if the studied rock lacks of cordierite or orthopyroxene.

  15. First Online Mass Measurements of Isobar Chains via Multi-Reflection Time-of-Flight Mass Spectrograph Coupled with GARIS-II

    E-print Network

    Schury, P; Ito, Y; Kaji, D; Soderstrom, P-A; Takamine, A; Arai, F; Haba, H; Jeong, S; Kimura, S; Koura, H; Miyatake, H; Morimoto, K; Morita, K; Ozawa, A; Reponen, M; Sonoda, T; Tanaka, T; Wollnik, H

    2015-01-01

    Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several heavy nuclei have been directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectile-like and target-like particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were observed. Precision atomic mass values were determined for 205,206Fr, 201At, and 201Po.

  16. Isobaric yield ratio difference between the 140 $A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions studied by antisymmetric molecular dynamics model

    E-print Network

    C. Y. Qiao; H. L. Wei; C. W. Ma; Y. L. Zhang; S. S. Wang

    2015-10-27

    \\item[Background] The isobaric yield ratio difference (IBD) method is found to be sensitive to the density difference of neutron-rich nucleus induced reaction around the Fermi energy. \\item[Purpose] An investigation is performed to study the IBD results in the transport model. \\item[Methods] The antisymmetric molecular dynamics (AMD) model plus the sequential decay model GEMINI are adopted to simulate the 140$A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions. A relative small coalescence radius R$_c =$ 2.5 fm is used for the phase space at $t =$ 500 fm/c to form the hot fragment. Two limitations on the impact parameter ($b1 = 0 - 2$ fm and $b2 = 0 - 9$ fm) are used to study the effect of central collisions in IBD. \\item[Results] The isobaric yield ratios (IYRs) for the large--$A$ fragments are found to be suppressed in the symmetric reaction. The IBD results for fragments with neutron-excess $I = $ 0 and 1 are obtained. A small difference is found in the IBDs with the $b1$ and $b2$ limitations in the AMD simulated reactions. The IBD with $b1$ and $b2$ are quite similar in the AMD + GEMINI simulated reactions. \\item[Conclusions] The IBDs for the $I =$ 0 and 1 chains are mainly determined by the central collisions, which reflects the nuclear density in the core region of the reaction system. The increasing part of the IBD distribution is found due to the difference between the densities in the peripheral collisions of the reactions. The sequential decay process influences the IBD results. The AMD + GEMINI simulation can better reproduce the experimental IBDs than the AMD simulation.

  17. The Rate-Controlled Constrained-Equilibrium Approach to Far-From-Local-Equilibrium Thermodynamics

    E-print Network

    Beretta, Gian Paolo

    The Rate-Controlled Constrained-Equilibrium (RCCE) method for the description of the time-dependent behavior of dynamical systems in non-equilibrium states is a general, effective, physically based method for model order ...

  18. Equilibrium coexistence of three amphiboles

    USGS Publications Warehouse

    Robinson, P.; Jaffe, H.W.; Klein, C., Jr.; Ross, M.

    1969-01-01

    Electron probe and wet chemical analyses of amphibole pairs from the sillimanite zone of central Massachusetts and adjacent New Hampshire indicated that for a particular metamorphic grade there should be a restricted composition range in which three amphiboles can coexist stably. An unequivocal example of such an equilibrium three amphibole rock has been found in the sillimanite-orthoclase zone. It contains a colorless primitive clinoamphibole, space group P21/m, optically and chemically like cummingtonite with blue-green hornblende exsolution lamellae on (100) and (-101) of the host; blue-green hornblende, space group C2/m, with primitive cummingtonite exsolution lamellae on (100) and (-101) of the host; and pale pinkish tan anthophyllite, space group Pnma, that is free of visible exsolution lamellae but is a submicroscopic intergrowth of two orthorhombic amphiboles. Mutual contacts and coarse, oriented intergrowths of two and three host amphiboles indicate the three grew as an equilibrium assemblage prior to exsolution. Electron probe analyses at mutual three-amphibole contacts showed little variation in the composition of each amphibole. Analyses believed to represent most closely the primary amphibole compositions gave atomic proportions on the basis of 23 oxygens per formula unit as follows: for primitive cummingtonite (Na0.02Ca0.21- Mn0.06Fe2+2.28Mg4.12Al0.28) (Al0.17Si7.83), for hornblende (Na0.35Ca1.56Mn0.02Fe1.71Mg2.85Al0.92) (Al1.37Si6.63), and for anthophyllite (Na0.10Ca0.06Mn0.06Fe2.25Mg4.11Al0.47) (Al0.47Si7.53). The reflections violating C-symmetry, on X-ray single crystal photographs of the primitive cummingtonite, are weak and diffuse, and suggest a partial inversion from a C-centered to a primitive clinoamphibole. Single crystal photographs of the anthophyllite show split reflections indicating it is an intergrowth of about 80% anthophyllite and about 20% gedrite which differ in their b crystallographic dimensions. Split reflections are characteristic of all analyzed orthorhombic amphiboles so far examined from Massachusetts and New Hampshire except the most aluminous gedrites, and the relative intensity of the gedrite reflections is roughly proportional to the degree of Na and Al substitution. Thin sections of a few of these anthophyllite specimens show lamellae parallel to (010) that are just resolved with a high power objective. ?? 1969 Springer-Verlag.

  19. Implementing an Equilibrium Law Teaching Sequence for Secondary School Students to Learn Chemical Equilibrium

    ERIC Educational Resources Information Center

    Ghirardi, Marco; Marchetti, Fabio; Pettinari, Claudio; Regis, Alberto; Roletto, Ezio

    2015-01-01

    A didactic sequence is proposed for the teaching of chemical equilibrium law. In this approach, we have avoided the kinetic derivation and the thermodynamic justification of the equilibrium constant. The equilibrium constant expression is established empirically by a trial-and-error approach. Additionally, students learn to use the criterion of…

  20. Chapter 9. Chemical Equilibrium 9.1 The Nature of Chemical Equilibrium

    E-print Network

    Ihee, Hyotcherl

    ; each is raised to a power equal to its coefficient in the balanced chemical equation for the reactionChapter 9. Chemical Equilibrium #12;9.1 The Nature of Chemical Equilibrium -Approach to Equilibrium is an inherent property of the chemical reaction itself and does not depend on the specific initial

  1. A Network Equilibrium FrameworkA Network Equilibrium Framework for Internet Advertising:for Internet Advertising

    E-print Network

    Nagurney, Anna

    Internet marketing strategiescompetitive Internet marketing strategies as a network equilibrium problem for the equilibrium of competitive Internet marketing strategies.competitive Internet marketing strategies. #12.equilibrium solution. --size of the Internet marketing budget is--size of the Internet marketing budget

  2. Chemical equilibrium in supercritical fluids: Solvent effects on the dimerization equilibrium constant

    E-print Network

    Rabani, Eran

    supercritical sol- vents CO2 , CHF3 , CClF3 , Ar, and Xe across the whole solvent density range, from gasChemical equilibrium in supercritical fluids: Solvent effects on the dimerization equilibrium; accepted 27 February 2002 We study dimerization equilibrium between two dilute solutes in a supercritical

  3. Zeroth Law, Entropy, Equilibrium, and All That

    ERIC Educational Resources Information Center

    Canagaratna, Sebastian G.

    2008-01-01

    The place of the zeroth law in the teaching of thermodynamics is examined in the context of the recent discussion by Gislason and Craig of some problems involving the establishment of thermal equilibrium. The concept of thermal equilibrium is introduced through the zeroth law. The relation between the zeroth law and the second law in the…

  4. The Equilibrium of Life-Career Planning

    NASA Astrophysics Data System (ADS)

    Byars-Winston, Angela

    Over a 100 years ago, fixed wing aircraft flight was made possible by Orville and Wilbur Wright's breakthrough invention of a three-axis control that allowed effective steering and maintenance of airplanes' equilibrium. The significance of the Wright brothers' control invention is that it facilitated recovery of lateral balance, or equilibrium, when the wind tilts the aircraft to one side or another.

  5. Ringed accretion disks: equilibrium configurations

    E-print Network

    D. Pugliese; Z. Stuchlík

    2015-10-13

    We investigate a model of ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the General Relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can be then determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high energy phenomena demonstrated in active galactic nuclei.

  6. Ringed Accretion Disks: Equilibrium Configurations

    NASA Astrophysics Data System (ADS)

    Pugliese, D.; Stuchlík, Z.

    2015-12-01

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  7. Probing local equilibrium in nonequilibrium fluids.

    PubMed

    del Pozo, J J; Garrido, P L; Hurtado, P I

    2015-08-01

    We use extensive computer simulations to probe local thermodynamic equilibrium (LTE) in a quintessential model fluid, the two-dimensional hard-disks system. We show that macroscopic LTE is a property much stronger than previously anticipated, even in the presence of important finite-size effects, revealing a remarkable bulk-boundary decoupling phenomenon in fluids out of equilibrium. This allows us to measure the fluid's equation of state in simulations far from equilibrium, with an excellent accuracy comparable to the best equilibrium simulations. Subtle corrections to LTE are found in the fluctuations of the total energy which strongly point to the nonlocality of the nonequilibrium potential governing the fluid's macroscopic behavior out of equilibrium. PMID:26382354

  8. Relativistic Equilibrium Distribution by Relative Entropy Maximization

    NASA Astrophysics Data System (ADS)

    Nakamura, T. K.

    2009-12-01

    The equilibrium distribution function of relativistic plasmas has been calculated based on the maximum entropy principle. The equilibrium distribution function is a necessary ingredient for theoretical or numerical study of various plasma processes. Though the relativistic equilibrium state has been long believed to be the Juttner distribution, a number of papers have been published in recent years proposing alternative equilibrium states. However, some of these papers do not pay enough attention to the covariance of distribution functions, resulting confusion in equilibrium states. Starting from a fully covariant expression to avoid this confusion, it has been shown in the present study that the Juttner distribution is the maximum entropy state if we assume the Lorentz symmetry.

  9. Disturbances in equilibrium function after major earthquake

    NASA Astrophysics Data System (ADS)

    Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi

    2012-10-01

    Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.

  10. H2O activity in concentrated KCl and KCl-NaCl solutions at high temperatures and pressures measured by the brucite-periclase equilibrium

    NASA Astrophysics Data System (ADS)

    Aranovich, L. Y.; Newton, R. C.

    H2O activities in supercritical fluids in the system KCl-H2O-(MgO) were measured at pressures of 1, 2, 4, 7, 10 and 15 kbar by numerous reversals of vapor compositions in equilibrium with brucite and periclase. Measurements spanned the range 550-900°C. A change of state of solute KCl occurs as pressures increase above 2kbar, by which H2O activity becomes very low and, at pressures of 4kbar and above, nearly coincident with the square of the mole fraction (xH2O). The effect undoubtedly results primarily from ionic dissociation as H2O density (?H2O) approaches 1gm/cm3, and is more pronounced than in the NaCl-H2O system at the same P-T-X conditions. Six values of solute KCl activity were yielded by terminal points of the isobaric brucite-periclase T-xH2O curves where sylvite saturation occurs. The H2O mole fraction of the isobaric invariant assemblage brucite-periclase-sylvite-fluid is near 0.52 at all pressures, and the corresponding temperatures span only 100°C between 1 and 15kbar. This remarkable convergence of the isobaric equilibrium curves reflects the great influence of pressure on lowering of both KCl and H2O activities. The H2O and KCl activities can be expressed by the formulas: aH2O=?H2O[xH2O+(1+(1+?)xKCl)], and aKCL=?KCl[(1+?)xKCl/(xH2O+(1+?)xKCl)](1+?), where ? is a degree of dissociation parameter which increases from zero at the lowest pressures to near one at high pressures and the ?'s are activity coefficients based on an empirical regular solution parameter W: ln ?i=(1-xi)2W. Least squares fitting of our H2O and KCl activity data evaluates the parameters: ?=exp(4.166 -2.709/?H2O) - 212.1P/T, and W=(-589.6-23.10P) /T, with ?H2O in gm/cm3, P in kbar and T in K. The standard deviation from the measured activities is only +/-0.014. The equations define isobaric liquidus curves, which are in perfect agreement with previous DTA liquidus measurements at 0.5-2kbar, but which depart progressively from their extrapolation to higher pressures because of the pressure-induced dissociation effect. The great similarity of the NaCl-H2O and KCl-H2O systems suggests that H2O activities in the ternary NaCl-KCl-H2O system can be described with reasonable accuracy by assuming proportionality between the binary systems. This assumption was verified by a few reconnaissance measurements at 10kbar of the brucite-periclase equilibrium with a Na/(Na+K) ratio of 0.5 and of the saturation temperature for Na/(Na+K) of 0.35 and 0.50. At that pressure the brucite-periclase curves reach a lowest xH2O of 0.45 and a temperature of 587°C before salt saturation occurs, values considerably lower than in either binary. This double-salt eutectic effect may have a significant application to natural polyionic hypersaline solutions in the deep crust and upper mantle in that higher solute concentrations and very low H2O activities may be realized in complex solutions before salt saturation occurs. Concentrated salt solutions seem, from this standpoint, and also because of high mechanical mobility and alkali-exchanging potential, feasible as metasomatic fluids for a variety of deep-crust and upper mantle processes.

  11. The Conceptual Change Approach to Teaching Chemical Equilibrium

    ERIC Educational Resources Information Center

    Canpolat, Nurtac; Pinarbasi, Tacettin; Bayrakceken, Samih; Geban, Omer

    2006-01-01

    This study investigates the effect of a conceptual change approach over traditional instruction on students' understanding of chemical equilibrium concepts (e.g. dynamic nature of equilibrium, definition of equilibrium constant, heterogeneous equilibrium, qualitative interpreting of equilibrium constant, changing the reaction conditions). This…

  12. Local Nash equilibrium in social networks.

    PubMed

    Zhang, Yichao; Aziz-Alaoui, M A; Bertelle, Cyrille; Guan, Jihong

    2014-01-01

    Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures. PMID:25169150

  13. Local Nash Equilibrium in Social Networks

    NASA Astrophysics Data System (ADS)

    Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

    2014-08-01

    Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.

  14. Local Nash Equilibrium in Social Networks

    PubMed Central

    Zhang, Yichao; Aziz-Alaoui, M. A.; Bertelle, Cyrille; Guan, Jihong

    2014-01-01

    Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures. PMID:25169150

  15. Performance of the thermodynamic properties models in ASPEN. [Freon 12 and Freon 22

    SciTech Connect

    Fish, L.W.; Evans, D.R.

    1982-01-01

    In the course of performing a number of analyses using ASPEN, the performance of the ASPEN models for computing thermodynamic properties has been observed. Pure-component properties for propane, isobutane, Freon 12 and Freon 22 and mixture properties for the propane-isobutane and the ethanol-water systems have been computed and the results compared with available data sources and with independent sources of computed properties. The built-in data regression system (DRS) of ASPEN was used to regress P-V-T and enthalpy departure data for isobutane to determine model-specific parameters. The extended Antoine vapor pressure parameters were calculated for Freon 12. The ethanol-water vapor-liquid equilibrium region was studied throughout the composition range for three isobaric data sets. Several activity coefficient models in ASPEN were fit to the data using various user-specified property routes.

  16. Isobaric heating and cooling path of the lower crust of a Variscan exotic unit: evidences from P -T estimates in NW Iberian metapelitic granulites

    NASA Astrophysics Data System (ADS)

    Alampi, A.; Gomez Barreiro, J.; Alvarez Valero, A.; Castiñeiras, P.

    2012-12-01

    Allochthonous complexes (AC) in NW Iberia consist of a pile of exotic units characterized by distinct tectonothermal evolution and lithological association, and separated from each other by tectonic contacts, either thrust or extensional detachments. In the Órdenes AC, three groups of units are recognized from bottom to top in the pile: Basal, Ophiolitic and Upper units. Upper units comprise an ensemble of arc-related rocks with a lower section that underwent a high-P and high-T (HP-HT) evolution, and an upper section with an intermediate - pressure (IP) evolution. Extensional detachments have been commonly identifying at the boundary between HP-HT and IP Upper units, like the Fornás and Corredoiras detachments. Pelitic granulites from one IP upper unit, the O Pino unit, have been investigated. Petrologic studies reveal an isobaric tectono-metamorphic crustal evolution throughout a multidisciplinary integration of: (i) detailed microstructural analysis; (ii) EMP mineral chemistry; (iii) mass-balance of the key and representative chemical reactions observed in the microstructures and subsequent interpretation of the reaction sequence; (iv) P-T estimates and paths from phase diagram modeling. Results in the NCKFMASHT system describe an isobaric (c. 7 kbar) continuous heating (and later cooling) evolution ranging from c. 620 to 680 C crossing into the melt-bearing stability fields. These achieved anatectic conditions are evidenced by the presence of both leucosomes (quartz, plagioclase and muscovite) and glass inclusions, mainly in local garnet cores through the dehydration/melting reactions of muscovite first and biotite later. Chemically distinct generations of garnet and plagioclase are evident and stoichiometrically balance each other in continuous reactions. They are consistent with the observations of both a garnet overgrowth and large patches of plagioclase which host euhedral, smaller garnets. In the cooling episode, the newly-grown garnet reacted with melt and formed a retrograde biotite + aluminosilicate + muscovite generation wrapping around the leucosomes or within the matrix. This implicates the existence of a localized thermal event in the base of the O Pino unit. The structural context of these rocks may represent the origin of the isobaric path as an important extensional shear zone (Fornás detachment) has been localized below the pelitic granulites. The Fornás detachment put in contact the O Pino unit from the HP-HT rocks of the Fornás unit (> 750C,15kbar). The thermal contrast between both units may generate a localized heating at the base of the O Pino unit which is a recognized effect in other extensional detachments. This fact is in accordance with the description of syn-kinematic melts intruded into the Fornás detachment in other NW Iberian areas. We may also speculate with a different scenario where the evolution of the pelitic granulites represent a relic of primitive thermal event barely recognized across the IP Upper units for which more geohronological constraint is still needed.

  17. What's quasi-equilibrium all WhatWhatWhat'''s quasis quasis quasi---equilibrium allequilibrium allequilibrium all

    E-print Network

    Plant, Robert

    What's quasi-equilibrium all about? WhatWhatWhat'''s quasis quasis quasi---equilibrium fluxes until equilibrium achieved A long time Repeating 3hr cycles #12;Equilibrium response Decay consistent with forcing Fluctuations around an equilibrium mass flux Rapid triggering but variable magnitude

  18. A randomized clinical study comparing spinal anesthesia with isobaric levobupivacaine with fentanyl and hyperbaric bupivacaine with fentanyl in elective cesarean sections

    PubMed Central

    Goyal, Ayesha; Shankaranarayan, P.; Ganapathi, P.

    2015-01-01

    Background: To date, racemic bupivacaine is the most popular local anesthetic for spinal anesthesia in parturients undergoing elective cesarean delivery. With the introduction of levobupivacaine as pure S (–) enantiomer of bupivacaine which offers advantages of lower cardiotoxicity and neurotoxicity and shorter motor block duration, its use has widely increased in India. However, very few studies have been conducted about its efficacy in obstetric anesthesia. Thus, this study was undertaken to compare the sensorial, motor block levels, and side-effects of equal doses of hyperbaric bupivacaine and levobupivacaine with intrathecal fentanyl addition in elective cesarean cases. Materials and Methods: After approval of College Ethical Committee, 30 parturient with American Society of Anesthesiologists I-II undergoing elective cesarean section were enrolled for study with their informed consent. They were randomly divided equally to either Group BF receiving 10 mg (2 ml) hyperbaric bupivacaine and 25 mcg (0.5 ml) fentanyl, or Group LF receiving 10 mg (2 ml) isobaric levobupivacaine and 25 mcg (0.5 ml) fentanyl. Sensory and motor block characteristics of the groups were assessed with pinprick, cold swab, and Bromage scale; observed hemodynamic changes and side-effects were recorded. Effects on the neonate were observed by APGAR score at 1 and 5 min and umbilical cord blood gas analysis. Results: Hemodynamic parameters like mean arterial pressure of Group BF were found to be lower. Group BF exhibited maximum motor block level whereas in Group LF, max sensorial block level and postoperative visual analog scale scores were higher. Umbilical blood gas pCO2 was slightly higher, and pO2 was marginally lower in Group BF. Onset of motor block time, time to max motor block, time to T10 sensorial block, reversal of two dermatome, the first analgesic need were similar in both groups. Conclusion: Intrathecal isobaric levobupivacaine-fentanyl combination is a good alternative to hyperbaric bupivacaine-fentanyl combination in cesarean surgery as it is less effective in motor block, it maintains hemodynamic stability at higher sensorial block levels. PMID:25886422

  19. Hexagonal honeycomb foams Foams out of mechanical equilibrium

    E-print Network

    Cox, Simon

    Hexagonal honeycomb foams Foams out of mechanical equilibrium Foams out of physicochemical equilibrium Dissipation Mechanisms in Bubble Scale Foam Rheology Departures from Princen's Sheared Honeycomb P, Embley, Oguey Dissipation Mechanisms #12;Hexagonal honeycomb foams Foams out of mechanical equilibrium

  20. Master thesis Non-equilibrium Solidification

    E-print Network

    Cambridge, University of

    Metallurgy Graduate Institute of Ferrous Technology Pohang University of Science and Technology 2011 #12-equilibrium solidification of -TRIP steel Computational Metallurgy 2011 Advisor: Prof. Suh, Dong-Woo Text in English Abstract

  1. Points of Equilibrium in Electrostatic Fields.

    ERIC Educational Resources Information Center

    Rogers, Peter J.

    1979-01-01

    Discusses the electric field line pattern for four equal charges of the same sign placed at the corners of a square. The electric field intensity and the point of equilibrium are interpreted, taking into account three dimensions. (HM)

  2. Quasilocal energy and thermodynamic equilibrium conditions

    E-print Network

    Uzun, Nezihe

    2015-01-01

    Equilibrium thermodynamic laws are typically applied to horizons in general relativity without stating the conditions that bring them into equilibrium. We fill this gap by applying a new thermodynamic interpretation to a generalized Raychaudhuri equation for a closed spacelike 2-surface, the "screen", which encompasses a system of arbitrary size in nonequilibrium with its surroundings in general. In the case of spherical symmetry this enables us to identify quasilocal thermodynamic potentials directly related to standard quasilocal energy definitions. Quasilocal thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature of the screen. Moreover, without any direct reference to surface gravity, we find that the system comes into quasilocal thermodynamic equilibrium when the screen is located at a generalized apparent horizon. Examples of the Schwarzschild, Friedmann-Lemaitre and Lemaitre-Tolman geometries are investigated and compared. Conditions for the quasilocal thermodynamic and hydrody...

  3. Equilibrium Reconstruction on the Large Helical Device

    SciTech Connect

    Samuel A. Lazerson, D. Gates, D. Monticello, H. Neilson, N. Pomphrey, A. Reiman S. Sakakibara, and Y. Suzuki

    2012-07-27

    Equilibrium reconstruction is commonly applied to axisymmetric toroidal devices. Recent advances in computational power and equilibrium codes have allowed for reconstructions of three-dimensional fields in stellarators and heliotrons. We present the first reconstructions of finite beta discharges in the Large Helical Device (LHD). The plasma boundary and magnetic axis are constrained by the pressure profile from Thomson scattering. This results in a calculation of plasma beta without a-priori assumptions of the equipartition of energy between species. Saddle loop arrays place additional constraints on the equilibrium. These reconstruction utilize STELLOPT, which calls VMEC. The VMEC equilibrium code assumes good nested flux surfaces. Reconstructed magnetic fields are fed into the PIES code which relaxes this constraint allowing for the examination of the effect of islands and stochastic regions on the magnetic measurements.

  4. Spreadsheet Templates for Chemical Equilibrium Calculations.

    ERIC Educational Resources Information Center

    Joshi, Bhairav D.

    1993-01-01

    Describes two general spreadsheet templates to carry out all types of one-equation chemical equilibrium calculations encountered by students in undergraduate chemistry courses. Algorithms, templates, macros, and representative examples are presented to illustrate the approach. (PR)

  5. An Elementary Discussion of Chemical Equilibrium.

    ERIC Educational Resources Information Center

    David, Carl W.

    1988-01-01

    This discussion uses a more difficult reaction as the prototype to derive the standard equation for chemical equilibrium. It can be used by students who can understand and use partial derivatives. (CW)

  6. An Equilibrium Model of Rare Event Premia

    E-print Network

    Liu, Jun

    2002-08-12

    In this paper, we study the asset pricing implication of imprecise knowledge about rare events. Modeling rare events as jumps in the aggregate endowment, we explicitly solve the equilibrium asset prices in a pure-exchange ...

  7. Edge Equilibrium Code (EEC) For Tokamaks

    SciTech Connect

    Li, Xujling

    2014-02-24

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids

  8. Non-equilibrium interfaces in colloidal fluids

    E-print Network

    Markus Bier; Daniel Arnold

    2013-12-03

    The time-dependent structure, interfacial tension, and evaporation of an oversaturated colloid-rich (liquid) phase in contact with an undersaturated colloid-poor (vapor) phase of a colloidal dispersion is investigated theoretically during the early-stage relaxation, where the interface is relaxing towards a local equilibrium state while the bulk phases are still out of equilibrium. Since systems of this type exhibit a clear separation of colloidal and solvent relaxation time scales with typical times of interfacial tension measurements in between, they can be expected to be suitable for analogous experimental studies, too. The major finding is that, irrespective of how much the bulk phases differ from two-phase coexistence, the interfacial structure and the interfacial tension approach those at two-phase coexistence during the early-stage relaxation process. This is a surprising observation since it implies that the relaxation towards global equilibrium of the interface is not following but preceding that of the bulk phases. Scaling forms for the local chemical potential, the flux, and the dissipation rate exhibit qualitatively different leading order contributions depending on whether an equilibrium or a non-equilibrium system is considered. The degree of non-equilibrium between the bulk phases is found to not influence the qualitative relaxation behavior (i.e., the values of power-law exponents), but to determine the quantitative deviation of the observed quantities from their values at two-phase coexistence. Whereas the underlying dynamics differs between colloidal and molecular fluids, the behavior of quantities such as the interfacial tension approaching the equilibrium values during the early-stage relaxation process, during which non-equilibrium conditions of the bulk phases are not changed, can be expected to occur for both types of systems.

  9. Theory for non-equilibrium statistical mechanics.

    PubMed

    Attard, Phil

    2006-08-21

    This paper reviews a new theory for non-equilibrium statistical mechanics. This gives the non-equilibrium analogue of the Boltzmann probability distribution, and the generalization of entropy to dynamic states. It is shown that this so-called second entropy is maximized in the steady state, in contrast to the rate of production of the conventional entropy, which is not an extremum. The relationships of the new theory to Onsager's regression hypothesis, Prigogine's minimal entropy production theorem, the Langevin equation, the formula of Green and Kubo, the Kawasaki distribution, and the non-equilibrium fluctuation and work theorems, are discussed. The theory is worked through in full detail for the case of steady heat flow down an imposed temperature gradient. A Monte Carlo algorithm based upon the steady state probability density is summarized, and results for the thermal conductivity of a Lennard-Jones fluid are shown to be in agreement with known values. Also discussed is the generalization to non-equilibrium mechanical work, and to non-equilibrium quantum statistical mechanics. As examples of the new theory two general applications are briefly explored: a non-equilibrium version of the second law of thermodynamics, and the origin and evolution of life. PMID:16883388

  10. Global Metabolomic and Isobaric Tagging Capillary Liquid Chromatography–Tandem Mass Spectrometry Approaches for Uncovering Pathway Dysfunction in Diabetic Mouse Aorta

    PubMed Central

    2015-01-01

    Despite the prevalence of diabetes and the global health risks it poses, the biochemical pathogenesis of diabetic complications remains poorly understood with few effective therapies. This study employs capillary liquid chromatography (capLC) and tandem mass spectrometry (MS/MS) in conjunction with both global metabolomics and isobaric tags specific to amines and carbonyls to probe aortic metabolic content in diabetic mice with hyperglycemia, hyperlipidemia, hypertension, and stenotic vascular damage. Using these combined techniques, metabolites well-characterized in diabetes as well as novel pathways were investigated. A total of 53?986 features were detected, 719 compounds were identified as having significant fold changes (thresholds ?2 or ?0.5), and 48 metabolic pathways were found to be altered with at least 2 metabolite hits in diabetic samples. Pathways related to carbonyl stress, carbohydrate metabolism, and amino acid metabolism showed the greatest number of metabolite changes. Three novel pathways with previously limited or undescribed roles in diabetic complications—vitamin B6, propanoate, and butanoate metabolism—were also shown to be altered in multiple points along the pathway. These discoveries support the theory that diabetic vascular complications arise from the interplay of a myriad of metabolic pathways in conjunction with oxidative and carbonyl stress, which may provide not only new and much needed biomarkers but also insights into novel therapeutic targets. PMID:25368974

  11. Isobar-model partial-wave analysis of ?N-->??N in the c.m. energy range 1320-1930 MeV

    NASA Astrophysics Data System (ADS)

    Manley, D. Mark; Arndt, Richard A.; Goradia, Yogesh; Teplitz, Vigdor L.

    1984-09-01

    We study the reactions ?N-->??N in the center-of-mass energy range 1320-1930 MeV within the framework of the isobar model. The present analysis includes over 30% more events than the most extensive previous analysis. Data for ?-p-->?+?-n, ?-p-->?0?-p, ?+p-->?0?+p, and ?+p-->?+?+n are simultaneously fitted assuming production of ?, ?, ?(P33) and N*(P11). The cross section for ?-p-->?0?0n is predicted and found to be in good agreement with experiment. ?N-->?N* amplitudes for I=12 are investigated for the first time. We confirm the existence of a significant ?N* decay for the second P33 resonance and determine that ?N* is the dominant inelastic channel for the P31 partial wave. The ?N decay of the G17 wave is observed for the first time. Evidence is found for unestablished resonances near 1900 MeV in the S11, P11, P13, and F15 partial waves. We also discuss evidence for a second F35 resonance. Signs of resonant amplitudes determined from this analysis are compared with results of previous analyses and with predictions from several models.

  12. Nuclear structure beyond the neutron drip line: the lowest energy states in $^9$He via their T=5/2 isobaric analogs in $^9$Li

    E-print Network

    E. Uberseder; G. V. Rogachev; V. Z. Goldberg; E. Koshchiy; B. T. Roeder; M. Alcorta; G. Chubarian; B. Davids; C. Fu; J. Hooker; H. Jayatissa; D. Melconian; R. E. Tribble

    2015-04-03

    The level structure of the very neutron rich and unbound $^9$He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy $^9$He states exist with spins $J^\\pi=1/2^+$ and $J^\\pi=1/2^-$ and widths on the order of hundreds of keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the $^8$He$+n$ system, performed via a search for the T=5/2 isobaric analog states in $^9$Li populated through $^8$He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad $J^{\\pi}=1/2^+$ state in $^9$He located approximately 3 MeV above the neutron decay threshold.

  13. First and Second-Phase Transitions of Gases at Isobaric Process; Lennard-Jones (9,6) Gases with a Hard Core

    NASA Astrophysics Data System (ADS)

    Matsumoto, Akira

    2014-12-01

    The thermodynamic functions for Lennard-Jones (9,6) gases with a hard core that are evaluated till the third virial coefficients, are investigated at an isobaric process. Some thermodynamic functions are analytically expressed as functions of intensive variables, temperature, and pressure. Some thermodynamic quantities for carbon dioxide are calculated numerically and drawn graphically. In critical states, the heat capacity diverges to infinity at the critical point while the Gibbs free energy, volume, enthalpy, and entropy are continuous at the critical point. In the coexistence of two phases, the boiling temperatures and the enthalpy changes of vaporization are obtained by numerical calculations for 20 substances. The Gibbs free energy indicates a polygonal line; entropy, volume, and enthalpy jump from the liquid to gaseous phase at the boiling point. The heat capacity does not diverge to infinity but shows a finite discrepancy at boiling point. This suggests that a first-order phase transition at the boiling point and a second-order phase transition may occur at the critical point.

  14. Global metabolomic and isobaric tagging capillary liquid chromatography-tandem mass spectrometry approaches for uncovering pathway dysfunction in diabetic mouse aorta.

    PubMed

    Filla, Laura A; Yuan, Wei; Feldman, Eva L; Li, Shuwei; Edwards, James L

    2014-12-01

    Despite the prevalence of diabetes and the global health risks it poses, the biochemical pathogenesis of diabetic complications remains poorly understood with few effective therapies. This study employs capillary liquid chromatography (capLC) and tandem mass spectrometry (MS/MS) in conjunction with both global metabolomics and isobaric tags specific to amines and carbonyls to probe aortic metabolic content in diabetic mice with hyperglycemia, hyperlipidemia, hypertension, and stenotic vascular damage. Using these combined techniques, metabolites well-characterized in diabetes as well as novel pathways were investigated. A total of 53,986 features were detected, 719 compounds were identified as having significant fold changes (thresholds ? 2 or ? 0.5), and 48 metabolic pathways were found to be altered with at least 2 metabolite hits in diabetic samples. Pathways related to carbonyl stress, carbohydrate metabolism, and amino acid metabolism showed the greatest number of metabolite changes. Three novel pathways with previously limited or undescribed roles in diabetic complications--vitamin B6, propanoate, and butanoate metabolism--were also shown to be altered in multiple points along the pathway. These discoveries support the theory that diabetic vascular complications arise from the interplay of a myriad of metabolic pathways in conjunction with oxidative and carbonyl stress, which may provide not only new and much needed biomarkers but also insights into novel therapeutic targets. PMID:25368974

  15. Non-Equilibrium in Adsorbed Polymer Layers

    E-print Network

    Ben O'Shaughnessy; Dimitrios Vavylonis

    2004-11-01

    High molecular weight polymer solutions have a powerful tendency to deposit adsorbed layers when exposed to even mildly attractive surfaces. The equilibrium properties of these dense interfacial layers have been extensively studied theoretically. A large body of experimental evidence, however, indicates that non-equilibrium effects are dominant whenever monomer-surface sticking energies are somewhat larger than kT, a common case. Polymer relaxation kinetics within the layer are then severely retarded, leading to non-equilibrium layers whose structure and dynamics depend on adsorption kinetics and layer ageing. Here we review experimental and theoretical work exploring these non-equilibrium effects, with emphasis on recent developments. The discussion addresses the structure and dynamics in non-equilibrium polymer layers adsorbed from dilute polymer solutions and from polymer melts and more concentrated solutions. Two distinct classes of behaviour arise, depending on whether physisorption or chemisorption is involved. A given adsorbed chain belonging to the layer has a certain fraction of its monomers bound to the surface, f, and the remainder belonging to loops making bulk excursions. A natural classification scheme for layers adsorbed from solution is the distribution of single chain f values, P(f), which may hold the key to quantifying the degree of irreversibility in adsorbed polymer layers. Here we calculate P(f) for equilibrium layers; we find its form is very different to the theoretical P(f) for non-equilibrium layers which are predicted to have infinitely many statistical classes of chain. Experimental measurements of P(f) are compared to these theoretical predictions.

  16. Non-Equilibrium Transitions of Heliospheric plasma

    NASA Astrophysics Data System (ADS)

    Livadiotis, G.; McComas, D. J.

    2011-12-01

    Recent advances in Space Physics theory have established the connection between non-extensive Statistical Mechanics and space plasmas by providing a theoretical basis for the empirically derived kappa distributions commonly used to describe the phase space distribution functions of these systems [1]. The non-equilibrium temperature and the kappa index that govern these distributions are the two independent controlling parameters of non-equilibrium systems [1-3]. The significance of the kappa index is primarily given by its role in identifying the non-equilibrium stationary states, and measuring their "thermodynamic distance" from thermal equilibrium [4], while its physical meaning is connected to the correlation between the system's particles [5]. For example, analysis of the IBEX high Energetic Neutral Atom spectra [6] showed that the vast majority of measured kappa indices are between ~1.5 and ~2.5, consistent with the far-equilibrium "cavity" of minimum entropy discovered by Livadiotis & McComas [2]. Spontaneous procedures that can increase the entropy, move the system gradually toward equilibrium, that is the state with the maximum (infinite) kappa index. Other external factors that may decrease the entropy, move the system back to states further from equilibrium where the kappa indices are smaller. Newly formed pick-up ions can play this critical role in the solar wind and other space plasmas. We have analytically shown that their highly ordered motion can reduce the average entropy in the plasma beyond the termination shock, inside the inner heliosheath [7]. Non-equilibrium transitions have a key role in understanding the governing thermodynamical processes of space plasmas. References 1. Livadiotis, G., & McComas, D. J. 2009, JGR, 114, 11105. 2. Livadiotis, G., & McComas, D. J. 2010a, ApJ, 714, 971. 3. Livadiotis, G., & McComas, D. J. 2010c, in AIP Conf. Proc. 9, Pickup Ions Throughout the Heliosphere and Beyond, ed. J. LeRoux, V. Florinski, G. P. Zank, & A. Coates (Melville, NY: AIP), 70. 4. Livadiotis, G., & McComas, D. J. 2010b, PhyS, 82, 035003. 5. Livadiotis, G., & McComas, D. J. 2011, ApJ, Invariant kappa distribution in space plasmas out of equilibrium, in press. 6. Livadiotis, G., McComas, D. J., Dayeh, M. A., Funsten, H. O., Schwadron, N. A. 2011, ApJ.., 734, 1. 7. Livadiotis, G., & McComas, D. J. 2011, ApJ, The influence of pick-up ions on space plasma distributions, in press.

  17. Quasilocal energy and thermodynamic equilibrium conditions

    NASA Astrophysics Data System (ADS)

    Uzun, Nezihe; Wiltshire, David L.

    2015-08-01

    Equilibrium thermodynamic laws are typically applied to horizons in general relativity without stating the conditions that bring them into equilibrium. We fill this gap by applying a new thermodynamic interpretation to a generalized Raychaudhuri equation for a worldsheet orthogonal to a closed spacelike two-surface, the ‘screen’, which encompasses a system of arbitrary size in nonequilibrium with its surroundings in general. In the case of spherical symmetry this enables us to identify quasilocal thermodynamic potentials directly related to standard quasilocal energy definitions. Quasilocal thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature of the screen. Moreover, without any direct reference to surface gravity, we find that the system comes into quasilocal thermodynamic equilibrium when the screen is located at a generalized apparent horizon. Examples of the Schwarzschild, Friedmann-Lemaître and Lemaître-Tolman geometries are investigated and compared. Conditions for the quasilocal thermodynamic and hydrodynamic equilibrium states to coincide are also discussed, and a quasilocal virial relation is suggested as a potential application of this approach.

  18. Quasilocal energy and thermodynamic equilibrium conditions

    E-print Network

    Nezihe Uzun; David L. Wiltshire

    2015-07-30

    Equilibrium thermodynamic laws are typically applied to horizons in general relativity without stating the conditions that bring them into equilibrium. We fill this gap by applying a new thermodynamic interpretation to a generalized Raychaudhuri equation for a worldsheet orthogonal to a closed spacelike 2-surface, the "screen", which encompasses a system of arbitrary size in nonequilibrium with its surroundings in general. In the case of spherical symmetry this enables us to identify quasilocal thermodynamic potentials directly related to standard quasilocal energy definitions. Quasilocal thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature of the screen. Moreover, without any direct reference to surface gravity, we find that the system comes into quasilocal thermodynamic equilibrium when the screen is located at a generalized apparent horizon. Examples of the Schwarzschild, Friedmann-Lema\\^itre and Lema\\^itre-Tolman geometries are investigated and compared. Conditions for the quasilocal thermodynamic and hydrodynamic equilibrium states to coincide are also discussed, and a quasilocal virial relation is suggested as a potential application of this approach.

  19. A Coupled Model for Radiative Transfer: Doppler Effects, Equilibrium and Non-Equilibrium Diffusion Asymptotics

    E-print Network

    Goudon, Thierry

    A Coupled Model for Radiative Transfer: Doppler Effects, Equilibrium and Non-Equilibrium Diffusion. The interaction terms take into account both scattering and absorption/emission phenomena, as well as Doppler-diffusion equations. Key words. Hydrodynamic limits. Diffusion approximation. Radiative transfer. Doppler correction

  20. Extragradient methods for searching for equilibrium points in the parametric problem of equilibrium programming

    NASA Astrophysics Data System (ADS)

    Artem'eva, L. A.

    2014-12-01

    The parametric problem of equilibrium programming is examined. The mathematical programming problem, the search for a saddle-point, the multicriteria search for a Pareto point, etc. are particular cases of this parametric problem. The primal and dual variants of the extragradient method are proposed as a tool for searching for equilibrium points. The convergence of both variants is analyzed.

  1. Partition Equilibrium Always Exists in Resource Selection Games

    E-print Network

    Anshelevich, Elliot

    Partition Equilibrium Always Exists in Resource Selection Games Elliot Anshelevich, Bugra Caskurlu consider the existence of Partition Equilibrium in Re- source Selection Games. Super-strong equilibrium to com- pute it efficiently. In a partition equilibrium, the set of players has a fixed partition

  2. Modelling the Electricity Market: from Equilibrium Models to Simulation

    E-print Network

    Lavaei, Javad

    Modelling the Electricity Market: from Equilibrium Models to Simulation Yoann Poirier Abstract - This paper aims at providing an overview of the different models used in order to describe the Electricity the Electricity Market: Cournot Equilibrium, Bertrand Equilibrium and Supply Function Equilibrium. I will make

  3. 46 CFR 42.20-12 - Conditions of equilibrium.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet...

  4. EQUILIBRIUM AND FLUX SURFACE ISSUES IN THE DESIGN OF NCSX

    E-print Network

    Hudson, Stuart

    EQUILIBRIUM AND FLUX SURFACE ISSUES IN THE DESIGN OF NCSX A. REIMAN,*a S. HIRSHMAN,b S. HUDSON,a D-5608 Received October 17, 2005 Accepted for Publication January 13, 2006 Equilibrium issues encountered on equilibrium mag- netic islands. Significant improvements have been made to the VMEC equilibrium code to deal

  5. Non-equilibrium Luttinger liquids Alexander D. Mirlin

    E-print Network

    Fominov, Yakov

    Non-equilibrium Luttinger liquids Alexander D. Mirlin Forschungszentrum & Universit¨at Karlsruhe, Rehovot http://www.tkm.uni-karlsruhe.de/mirlin/ #12;Plan · Non-equilibrium Luttinger liquid: Setups · Partial non-equilibrium · Tunneling DOS, zero-bias anomaly (ZBA), dephasing · Energy relaxation · Full non-equilibrium

  6. Non-equilibrium processes in modern semiconductor devices. Spring 2008.

    E-print Network

    Levi, Anthony F. J.

    EE 606 Non-equilibrium processes in modern semiconductor devices. Spring 2008. A. F. J. Levi TTh 11 in a regime dominated by non-equilibrium effects. However, most conventional semiconductor device courses still use equilibrium or near equilibrium concepts to describe device operation. The purpose

  7. 46 CFR 42.20-12 - Conditions of equilibrium.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet...

  8. 46 CFR 42.20-12 - Conditions of equilibrium.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet...

  9. 46 CFR 42.20-12 - Conditions of equilibrium.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet...

  10. 46 CFR 42.20-12 - Conditions of equilibrium.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet...

  11. Equilibrium versus disequilibrium of barchan dunes

    NASA Astrophysics Data System (ADS)

    El belrhiti, Hicham; Douady, Stéphane

    2011-02-01

    Barchans are crescentic dunes which occur in mainly mono-directional winds. Shape, aspect ratios and velocities of these dunes have been studied as if they were in equilibrium. However, following a study of the shape and migration of 11 barchans of different sizes for 18 months in the field on Moroccan Atlantic Sahara, we show that they only appear to be in a stationary state if studied over a long timeframe (at the scale of the year or several years), but are never in equilibrium at the scale of weeks or months. Rather, they are always 'trying' to reach a possible equilibrium state but never have enough time to accomplish this. This may be the main reason for the large variation observed in previous measurements, and justifies some caution in what can be deduced from them.

  12. Non-equilibrium quantum heat machines

    E-print Network

    Rober Alicki; David Gelbwaser-Klimovsky

    2015-07-07

    Standard heat machines (engine, heat pump, refrigerator) are composed of a system ("working fluid") coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) called sometimes work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines operating under their influences is limited by a generalized Carnot bound.

  13. Solving for MHD Equilibrium on Unstructured Grids

    NASA Astrophysics Data System (ADS)

    Thomas, Michael; Freidberg, Jeffrey

    1999-11-01

    The present work describes a method for determining the MHD equilibrium in an axi-symmetric torus using two-dimensional finite elements on an unstructured triangular grid. This work is motivated by the proposed development of an adaptive mesh stability code that will solve the ideal linearized stability problem with a resistive wall. In order to create an automatically adapting grid, an unstructured triangular grid is initially generated for the equilibrium evaluation. The Grad-Shafronov equation is modified to accommodate a static toroidal flow velocity. The resulting equation is then solved on the generated grid in the natural cylindrical (R, ?, Z) coordinate system. By working in the natural coordinate system, there are no singular points to be dealt with in the system. However, there are several numerical problems associated with solving the system of equations that are presented. Benchmark results against the Solov’ev equilibrium as well as the PEST and HELENA codes are also presented.

  14. Magnetospheric equilibrium configurations and slow adiabatic convection

    NASA Technical Reports Server (NTRS)

    Voigt, Gerd-Hannes

    1986-01-01

    This review paper demonstrates how the magnetohydrostatic equilibrium (MHE) theory can be used to describe the large-scale magnetic field configuration of the magnetosphere and its time evolution under the influence of magnetospheric convection. The equilibrium problem is reviewed, and levels of B-field modelling are examined for vacuum models, quasi-static equilibrium models, and MHD models. Results from two-dimensional MHE theory as they apply to the Grad-Shafranov equation, linear equilibria, the asymptotic theory, magnetospheric convection and the substorm mechanism, and plasma anisotropies are addressed. Results from three-dimensional MHE theory are considered as they apply to an intermediate analytical magnetospheric model, magnetotail configurations, and magnetopause boundary conditions and the influence of the IMF.

  15. Analytic prediction of airplane equilibrium spin characteristics

    NASA Technical Reports Server (NTRS)

    Adams, W. M., Jr.

    1972-01-01

    The nonlinear equations of motion are solved algebraically for conditions for which an airplane is in an equilibrium spin. Constrained minimization techniques are employed in obtaining the solution. Linear characteristics of the airplane about the equilibrium points are also presented and their significance in identifying the stability characteristics of the equilibrium points is discussed. Computer time requirements are small making the method appear potentially applicable in airplane design. Results are obtained for several configurations and are compared with other analytic-numerical methods employed in spin prediction. Correlation with experimental results is discussed for one configuration for which a rather extensive data base was available. A need is indicated for higher Reynolds number data taken under conditions which more accurately simulate a spin.

  16. Non-equilibrium quantum heat machines

    NASA Astrophysics Data System (ADS)

    Alicki, Robert; Gelbwaser-Klimovsky, David

    2015-11-01

    Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.

  17. Equilibrium vacancies and thermophysical properties of metals

    NASA Astrophysics Data System (ADS)

    Kraftmakher, Yaakov

    1998-06-01

    Despite a significant progress in studies of point defects, some important problems have not received unambiguous solutions. One of the most practically important questions relates to equilibrium concentrations of point defects. It is indeed surprising that this fundamental problem is still under debate. There exist two opposite viewpoints on equilibrium point defects in metals: (1) Defect contributions to the physical properties of metals at high temperatures are small and cannot be separated from the effects of anharmonicity. The only suitable methods are the positron-annihilation spectroscopy providing enthalpies of the vacancy formation and the differential dilatometry yielding equilibrium vacancy concentrations. The equilibrium vacancy concentrations at the melting points are in the range 10 -4 to 10 -3. Reasonable values of the formation enthalpies deduced from the nonlinear increase in the high-temperature specific heat of metals are accidental and the derived defect concentrations are improbably large, so that this approach is generally erroneous. (2) In many cases, defect contributions to the specific heat of metals are much larger than nonlinear effects of the anharmonicity and can be separated without crucial errors. This approach is quite adequate for determination of the defect parameters, especially, the equilibrium vacancy concentrations. The equilibrium concentrations at the melting points are of the order of 10 -3 in low-melting-point metals and of 10 -2 in high-melting-point metals. The strong nonlinear effects in the specific heat and thermal expansivity of metals at high temperatures can be explained by the formation of point defects. Examination of these effects rules out the anharmonicity as a possible origin of this phenomenon. Important arguments supporting this viewpoint have appeared in the last decade. It may turn out that just calorimetric determinations provide most reliable values of equilibrium vacancy concentrations in metals. The aim of the review is to discuss the experimental results and theoretical considerations favoring both claims. At present, the first point of view is shared by the majority of the scientific community. Regrettably, the data supporting the second viewpoint were never displayed and discussed together, and the criticism of this viewpoint never included a detailed analysis. In this review, the main attention is paid to equilibrium vacancies in metals and their relation to thermophysical properties of metals. Along with a discussion of experimental data and theoretical estimates now available, some approaches are proposed that seem to be most suitable to solve the question.

  18. Equilibrium partition function for nonrelativistic fluids

    NASA Astrophysics Data System (ADS)

    Banerjee, Nabamita; Dutta, Suvankar; Jain, Akash

    2015-10-01

    We construct an equilibrium partition function for a nonrelativistic fluid and use it to constrain the dynamics of the system. The construction is based on light cone reduction, which is known to reduce the Poincaré symmetry to Galilean in one lower dimension. We modify the constitutive relations of a relativistic fluid, and find that its symmetry broken phase—"null fluid" is equivalent to the nonrelativistic fluid. In particular, their symmetries, thermodynamics, constitutive relations, and equilibrium partition function match exactly to all orders in derivative expansion.

  19. Isodynamic axisymmetric equilibrium near the magnetic axis

    SciTech Connect

    Arsenin, V. V.

    2013-08-15

    Plasma equilibrium near the magnetic axis of an axisymmetric toroidal magnetic confinement system is described in orthogonal flux coordinates. For the case of a constant current density in the vicinity of the axis and magnetic surfaces with nearly circular cross sections, expressions for the poloidal and toroidal magnetic field components are obtained in these coordinates by using expansion in the reciprocal of the aspect ratio. These expressions allow one to easily derive relationships between quantities in an isodynamic equilibrium, in which the absolute value of the magnetic field is constant along the magnetic surface (Palumbo’s configuration)

  20. Steady entanglement out of thermal equilibrium

    E-print Network

    Bruno Bellomo; Mauro Antezza

    2015-08-31

    We study two two-level atomic quantum systems (qubits) placed close to a body held at a temperature different from that of the surrounding walls. While at thermal equilibrium the two-qubit dynamics is characterized by not entangled steady thermal states, we show that absence of thermal equilibrium may bring to the generation of entangled steady states. Remarkably, this entanglement emerges from the two-qubit dissipative dynamic itself, without any further external action on the two qubits, suggesting a new protocol to produce and protect entanglement which is intrinsically robust to environmental effects.

  1. Computing Properties Of Chemical Mixtures At Equilibrium

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.; Gordon, S.

    1995-01-01

    Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.

  2. Equilibrium partition function for nonrelativistic fluids

    E-print Network

    Nabamita Banerjee; Suvankar Dutta; Akash Jain

    2015-10-05

    We construct an equilibrium partition function for a non-relativistic fluid and use it to constrain the dynamics of the system. The construction is based on light cone reduction, which is known to reduce the Poincare symmetry to Galilean in one lower dimension. We modify the constitutive relations of a relativistic fluid, and find that its symmetry broken phase - `null fluid' is equivalent to the non-relativistic fluid. In particular, their symmetries, thermodynamics, constitutive relations, and equilibrium partition function match exactly to all orders in derivative expansion.

  3. Putting A Human Face on Equilibrium

    NASA Astrophysics Data System (ADS)

    Glickstein, Neil

    2005-03-01

    A short biography of chemist Fritz Haber is used to personalize the abstract concepts of equilibrium chemistry for high school students in an introductory course. In addition to giving the Haber Bosch process an historic, an economic, and a scientific background the reading and subsequent discussion allows students for whom the human perspective is of paramount importance a chance to investigate the irony of balance or equilibrium in Haber's life story. Since the inclusion of the Haber biography, performance in the laboratory and on examinations for those students who are usually only partially engaged has dramatically improved.

  4. Algorithm For Hypersonic Flow In Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Palmer, Grant

    1989-01-01

    Implicit, finite-difference, shock-capturing algorithm calculates inviscid, hypersonic flows in chemical equilibrium. Implicit formulation chosen because overcomes limitation on mathematical stability encountered in explicit formulations. For dynamical portion of problem, Euler equations written in conservation-law form in Cartesian coordinate system for two-dimensional or axisymmetric flow. For chemical portion of problem, equilibrium state of gas at each point in computational grid determined by minimizing local Gibbs free energy, subject to local conservation of molecules, atoms, ions, and total enthalpy. Major advantage: resulting algorithm naturally stable and captures strong shocks without help of artificial-dissipation terms to damp out spurious numerical oscillations.

  5. Equilibrium (a), (b) and para-equilibrium (c), (d) phase diagrams for the two steels received from POSCO

    E-print Network

    Cambridge, University of

    Equilibrium (a), (b) and para-equilibrium (c), (d) phase diagrams for the two steels received from POSCO 1000 1200 1400 1600 1800 0 20 40 60 80 100 35 wt.% (a) DT2_P: Equilibrium Amountofphase_P: Equilibrium Amountofphase/wt% Temperature / K Austenite ferrite Liquid Cementite Ferrite 51 wt

  6. Equilibrium and Non-equilibrium Kinetics of Self-Assembled Surfactant Monolayers: A Vibrational Sum-Frequency Study of

    E-print Network

    Richmond, Geraldine L.

    Equilibrium and Non-equilibrium Kinetics of Self-Assembled Surfactant Monolayers: A Vibrational Sum-mail: richmond@uoregon.edu Abstract: The adsorption, desorption, and equilibrium monomer exchange processes.e., the adsorption of adsorbates past the point of electrostatic equilibrium) was observed. This points out

  7. A Novel Function for Arabidopsis CYCLASE1 in Programmed Cell Death Revealed by Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Analysis of Extracellular Matrix Proteins*

    PubMed Central

    Smith, Sarah J.; Kroon, Johan T. M.; Simon, William J.; Slabas, Antoni R.; Chivasa, Stephen

    2015-01-01

    Programmed cell death is essential for plant development and stress adaptation. A detailed understanding of the signal transduction pathways that regulate plant programmed cell death requires identification of the underpinning protein networks. Here, we have used a protagonist and antagonist of programmed cell death triggered by fumonisin B1 as probes to identify key cell death regulatory proteins in Arabidopsis. Our hypothesis was that changes in the abundance of cell death-regulatory proteins induced by the protagonist should be blocked or attenuated by concurrent treatment with the antagonist. We focused on proteins present in the mobile phase of the extracellular matrix on the basis that they are important for cell–cell communications during growth and stress-adaptive responses. Salicylic acid, a plant hormone that promotes programmed cell death, and exogenous ATP, which can block fumonisin B1-induced cell death, were used to treat Arabidopsis cell suspension cultures prior to isobaric-tagged relative and absolute quantitation analysis of secreted proteins. A total of 33 proteins, whose response to salicylic acid was suppressed by ATP, were identified as putative cell death-regulatory proteins. Among these was CYCLASE1, which was selected for further analysis using reverse genetics. Plants in which CYCLASE1 gene expression was knocked out by insertion of a transfer-DNA sequence manifested dramatically increased cell death when exposed to fumonisin B1 or a bacterial pathogen that triggers the defensive hypersensitive cell death. Although pathogen inoculation altered CYCLASE1 gene expression, multiplication of bacterial pathogens was indistinguishable between wild type and CYCLASE1 knockout plants. However, remarkably severe chlorosis symptoms developed on gene knockout plants in response to inoculation with either a virulent bacterial pathogen or a disabled mutant that is incapable of causing disease in wild type plants. These results show that CYCLASE1, which had no known function hitherto, is a negative regulator of cell death and regulates pathogen-induced symptom development in Arabidopsis. PMID:25862728

  8. The director and molecular dynamics of the field-induced alignment of a Gay-Berne nematic phase: An isothermal-isobaric nonequilibrium molecular dynamics simulation study

    NASA Astrophysics Data System (ADS)

    Luckhurst, Geoffrey R.; Satoh, Katsuhiko

    2010-05-01

    Isothermal-isobaric molecular dynamics simulations have been performed for the generic Gay-Berne (GB) mesogen, GB(4.4, 20.0, 1, 1), to investigate director and molecular rotational motion during the field-induced alignment of a nematic. The alignment process for the director is discussed within the context of a hydrodynamic analysis based on the Ericksen-Leslie theory and this is found to predict the simulated behavior well. The dependence of the relaxation time for the alignment on the field strength is also in good accord with the theory. The rotational viscosity coefficient estimated from the simulation is smaller than that typically observed for real nematics and the possible reasons for this are discussed. However, the simulation results are found to follow not only the theory but also the experiments, at least qualitatively. No significant variation in the local and long-range structure of the nematic phase is found during the field-induced alignment process. In addition, we have explored the molecular dynamics in the nematic phase in the presence of the field using the first- and second-rank time autocorrelation functions. More importantly we are able to show that the director relaxation time is longer than that for molecular rotation. It is also possible to use the two orientational correlation times to explore the relationship between the rotational viscosity coefficient and the rotational diffusion constant. The diffusion constants determined from the orientational correlation times, based on the short-time expansion of the autocorrelation functions, are found to be significantly different. In consequence it is not possible to test, unambiguously, the relationship between the rotational viscosity coefficient and the rotational diffusion constant. However, it would seem that the second-rank rotational correlation time provides the most reliable route to the rotational viscosity coefficient.

  9. High-precision measurement of (186)Os/(188)Os and (187)Os/(188)Os: isobaric oxide corrections with in-run measured oxygen isotope ratios.

    PubMed

    Chu, Zhu-Yin; Li, Chao-Feng; Chen, Zhi; Xu, Jun-Jie; Di, Yan-Kun; Guo, Jing-Hui

    2015-09-01

    We present a novel method for high precision measurement of (186)Os/(188)Os and (187)Os/(188)Os ratios, applying isobaric oxide interference correction based on in-run measurements of oxygen isotopic ratios. For this purpose, we set up a static data collection routine to measure the main Os(16)O3(-) ion beams with Faraday cups connected to conventional 10(11) amplifiers, and (192)Os(16)O2(17)O(-) and (192)Os(16)O2(18)O(-) ion beams with Faraday cups connected to 10(12) amplifiers. Because of the limited number of Faraday cups, we did not measure (184)Os(16)O3(-) and (189)Os(16)O3(-) simultaneously in-run, but the analytical setup had no significant influence on final (186)Os/(188)Os and (187)Os/(188)Os data. By analyzing UMd, DROsS, an in-house Os solution standard, and several rock reference materials, including WPR-1, WMS-1a, and Gpt-5, the in-run measured oxygen isotopic ratios were proven to present accurate Os isotopic data. However, (186)Os/(188)Os and (187)Os/(188)Os data obtained with in-run O isotopic compositions for the solution standards and rock reference materials show minimal improvement in internal and external precision, compared to the conventional oxygen correction method. We concluded that, the small variations of oxygen isotopes during OsO3(-) analytical sessions are probably not the main source of error for high precision Os isotopic analysis. Nevertheless, use of run-specific O isotopic compositions is still a better choice for Os isotopic data reduction and eliminates the requirement of extra measurements of the oxygen isotopic ratios. PMID:26255581

  10. Equilibrium and off-equilibrium trap-size scaling in one-dimensional ultracold bosonic gases

    SciTech Connect

    Campostrini, Massimo; Vicari, Ettore

    2010-12-15

    We study some aspects of equilibrium and off-equilibrium quantum dynamics of dilute bosonic gases in the presence of a trapping potential. We consider systems with a fixed number of particles and study their scaling behavior with increasing the trap size. We focus on one-dimensional bosonic systems, such as gases described by the Lieb-Liniger model and its Tonks-Girardeau limit of impenetrable bosons, and gases constrained in optical lattices as described by the Bose-Hubbard model. We study their quantum (zero-temperature) behavior at equilibrium and off equilibrium during the unitary time evolution arising from changes of the trapping potential, which may be instantaneous or described by a power-law time dependence, starting from the equilibrium ground state for an initial trap size. Renormalization-group scaling arguments and analytical and numerical calculations show that the trap-size dependence of the equilibrium and off-equilibrium dynamics can be cast in the form of a trap-size scaling in the low-density regime, characterized by universal power laws of the trap size, in dilute gases with repulsive contact interactions and lattice systems described by the Bose-Hubbard model. The scaling functions corresponding to several physically interesting observables are computed. Our results are of experimental relevance for systems of cold atomic gases trapped by tunable confining potentials.

  11. Nonequilibrium Work Relations and Equilibrium Thermodynamics

    E-print Network

    Evans, Denis

    general formalism for deriving nonequilibrium free energy relations that can be applied in a very wide mechanical considerations. In 1854 Clausius proved his Theorem by assuming the Second "Law" of Thermodynamics1 CHAPTER 8. Nonequilibrium Work Relations and Equilibrium Thermodynamics "When one gets

  12. CONVERGENCE TO EQUILIBRIUM: ENTROPY PRODUCTION AND HYPOCOERCIVITY

    E-print Network

    Villani, Cédric

    of the second law of thermodynamics, but it is a theorem, as opposed to a postulate; - although not perfectly the constraints given by the conservation laws, which means mass and kinetic energy. Since the maximizer rigorous, the proof is beautiful; - this theorem applies in all generality, even far from equilibrium

  13. Exploring Chemical Equilibrium in Hot Jovians

    NASA Astrophysics Data System (ADS)

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Blecic, Jasmina; Challener, Ryan

    2016-01-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Yung 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime 0.1 to 1 bar. These results are compared to a variety of exoplanets(Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an up-dated thermodynamic library) is compared with the thermochemical model presented in Venotet al. (2012) for HD 209458b and HD 189733b. This same analysis is then applied to the cooler planet HD 97658b. Spectra are generated and we compare both models' outputs using the open source codetransit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. Thiswork was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  14. General Equilibrium Models: Improving the Microeconomics Classroom

    ERIC Educational Resources Information Center

    Nicholson, Walter; Westhoff, Frank

    2009-01-01

    General equilibrium models now play important roles in many fields of economics including tax policy, environmental regulation, international trade, and economic development. The intermediate microeconomics classroom has not kept pace with these trends, however. Microeconomics textbooks primarily focus on the insights that can be drawn from the…

  15. Spontaneity and Equilibrium II: Multireaction Systems

    ERIC Educational Resources Information Center

    Raff, Lionel M.

    2014-01-01

    The thermodynamic criteria for spontaneity and equilibrium in multireaction systems are developed and discussed. When N reactions are occurring simultaneously, it is shown that G and A will depend upon N independent reaction coordinates, ?a (a = 1,2, ..., N), in addition to T and p for G or T and V for A. The general criteria for spontaneity and…

  16. Phase Equilibrium Chemistry 243 David Ronis

    E-print Network

    Ronis, David M.

    Phase Equilibrium Chemistry 243 David Ronis McGill University An important class of equilibria involves the different equilibria established between dif- ferent states of matter, e.g., solids, liquids, and gases. As we shall now show, such equilibria are governed by very simple principles, essentially

  17. Group Contribution Methods for Phase Equilibrium Calculations.

    PubMed

    Gmehling, Jürgen; Constantinescu, Dana; Schmid, Bastian

    2015-07-24

    The development and design of chemical processes are carried out by solving the balance equations of a mathematical model for sections of or the whole chemical plant with the help of process simulators. For process simulation, besides kinetic data for the chemical reaction, various pure component and mixture properties are required. Because of the great importance of separation processes for a chemical plant in particular, a reliable knowledge of the phase equilibrium behavior is required. The phase equilibrium behavior can be calculated with the help of modern equations of state or g(E)-models using only binary parameters. But unfortunately, only a very small part of the experimental data for fitting the required binary model parameters is available, so very often these models cannot be applied directly. To solve this problem, powerful predictive thermodynamic models have been developed. Group contribution methods allow the prediction of the required phase equilibrium data using only a limited number of group interaction parameters. A prerequisite for fitting the required group interaction parameters is a comprehensive database. That is why for the development of powerful group contribution methods almost all published pure component properties, phase equilibrium data, excess properties, etc., were stored in computerized form in the Dortmund Data Bank. In this review, the present status, weaknesses, advantages and disadvantages, possible applications, and typical results of the different group contribution methods for the calculation of phase equilibria are presented. PMID:26247292

  18. The 'Schwarzschild-Kerr' Equilibrium Configurations

    SciTech Connect

    Manko, V. S.; Ruiz, E.

    2010-12-07

    We discuss the possibility of equilibrium between a Schwarzschild black hole possessing zero intrinsic angular momentum and a hyperextreme Kerr source. The balance occurs due to frame-dragging exerted by the latter source on the black-hole constituent, thus giving rise to a non-zero horizon's angular velocity parallel to the angular momentum of the Kerr object.

  19. Exploring Equilibrium Chemistry for Hot Exoplanets

    NASA Astrophysics Data System (ADS)

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Challener, Ryan

    2015-11-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Young 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime of 0.1 to 1 bar. These results are compared to a variety of exoplanets (Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an updated thermodynamic library) is validated with the thermochemical model presented in Venot et al. (2012) for HD 209458b and HD 189733b. This same analysis has then been extended to the cooler planet HD 97658b. Spectra are generated from both models’ abundances using the open source code transit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  20. Teaching Chemical Equilibrium with the Jigsaw Technique

    ERIC Educational Resources Information Center

    Doymus, Kemal

    2008-01-01

    This study investigates the effect of cooperative learning (jigsaw) versus individual learning methods on students' understanding of chemical equilibrium in a first-year general chemistry course. This study was carried out in two different classes in the department of primary science education during the 2005-2006 academic year. One of the classes…

  1. Calculating Shocks In Flows At Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Eberhardt, Scott; Palmer, Grant

    1988-01-01

    Boundary conditions prove critical. Conference paper describes algorithm for calculation of shocks in hypersonic flows of gases at chemical equilibrium. Although algorithm represents intermediate stage in development of reliable, accurate computer code for two-dimensional flow, research leading up to it contributes to understanding of what is needed to complete task.

  2. A Progression of Static Equilibrium Laboratory Exercises

    ERIC Educational Resources Information Center

    Kutzner, Mickey; Kutzner, Andrew

    2013-01-01

    Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…

  3. EQUILIBRIUM MOISTURE CONTENT OF PEARL MILLET

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Moisture content has a significant influence in the storability of cereal grains. The relationship of temperature, relative humidity, and equilibrium moisture can indicate the need for drying grain to improve storability and prevent grain mold development. This information is available for many grai...

  4. Chemical Equilibrium Composition of Aqueous Systems

    Energy Science and Technology Software Center (ESTSC)

    1996-12-30

    MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C.

  5. Payload specialists Patrick Baudry conducts equilibrium experiments

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Payload specialists Patrick Baudry participates in an experiment involving equilibrium and vertigo. He is anchored to the orbiter floor by foot restraints and is wearing a device over his eyes to measure angular head movement and up and down eye movement.

  6. RELAXATION METHODS FOR GENERALIZED NASH EQUILIBRIUM PROBLEMS

    E-print Network

    Kanzow, Christian

    RELAXATION METHODS FOR GENERALIZED NASH EQUILIBRIUM PROBLEMS WITH INEXACT LINE SEARCH Anna von method seems to be the only one that has been applied at least by a small group of different people methods available in the literature. One of the most popular ones is the so-called relaxation method which

  7. Equilibrium Molecular Thermodynamics from Kirkwood Sampling

    PubMed Central

    2015-01-01

    We present two methods for barrierless equilibrium sampling of molecular systems based on the recently proposed Kirkwood method (J. Chem. Phys.2009, 130, 134102). Kirkwood sampling employs low-order correlations among internal coordinates of a molecule for random (or non-Markovian) sampling of the high dimensional conformational space. This is a geometrical sampling method independent of the potential energy surface. The first method is a variant of biased Monte Carlo, where Kirkwood sampling is used for generating trial Monte Carlo moves. Using this method, equilibrium distributions corresponding to different temperatures and potential energy functions can be generated from a given set of low-order correlations. Since Kirkwood samples are generated independently, this method is ideally suited for massively parallel distributed computing. The second approach is a variant of reservoir replica exchange, where Kirkwood sampling is used to construct a reservoir of conformations, which exchanges conformations with the replicas performing equilibrium sampling corresponding to different thermodynamic states. Coupling with the Kirkwood reservoir enhances sampling by facilitating global jumps in the conformational space. The efficiency of both methods depends on the overlap of the Kirkwood distribution with the target equilibrium distribution. We present proof-of-concept results for a model nine-atom linear molecule and alanine dipeptide. PMID:25915525

  8. Thermodynamics of phase equilibrium in nonuniform fields

    NASA Astrophysics Data System (ADS)

    Vorob'ev, V. S.; Malyshenko, S. P.

    1997-10-01

    We obtain conditions of phase equilibrium of a substance in a nonuniform potential field of forces. If the force per mass unit is phase dependent, the field may induce a shift of phase equilibrium. In this case, chemical potentials of the substance do not coincide at the phase boundary with equal temperatures and pressures for each phase. The equality condition at the phase boundary in the presence of the field for the full chemical potentials of the phases, including the additional field component, can be reduced to the equality condition of the chemical potentials under different pressures for each phase. Thus the field-induced phase equilibrium becomes impossible for a given geometry, and the system has to change its phase abruptly when one of the phases reaches its spinodal state. An example of such a transition is the case of a liquid current-carrying conductor in its own magnetic field rapidly turning to a dispersion state (drops in vapor). Similar phenomena can occur at the final stage of electrical explosion of conductors. We also show that for a liquid dielectric in a nonuniform external electric field the thermodynamical equilibrium state is liquid with vapor bubbles, the latter being localized into the domain of the higher value of the field.

  9. Equilibrium gas flow computations. I - Accurate and efficient calculation of equilibrium gas properties

    NASA Technical Reports Server (NTRS)

    Liu, Yen; Vinokur, Marcel

    1989-01-01

    This paper treats the accurate and efficient calculation of thermodynamic properties of arbitrary gas mixtures for equilibrium flow computations. New improvements in the Stupochenko-Jaffe model for the calculation of thermodynamic properties of diatomic molecules are presented. A unified formulation of equilibrium calculations for gas mixtures in terms of irreversible entropy is given. Using a highly accurate thermo-chemical data base, a new, efficient and vectorizable search algorithm is used to construct piecewise interpolation procedures with generate accurate thermodynamic variable and their derivatives required by modern computational algorithms. Results are presented for equilibrium air, and compared with those given by the Srinivasan program.

  10. Effective equilibrium theory of nonequilibrium quantum transport

    SciTech Connect

    Dutt, Prasenjit; Koch, Jens; Han, Jong; Le Hur, Karyn

    2011-12-15

    The theoretical description of strongly correlated quantum systems out of equilibrium presents several challenges and a number of open questions persist. Here, we focus on nonlinear electronic transport through an interacting quantum dot maintained at finite bias using a concept introduced by Hershfield [S. Hershfield, Phys. Rev. Lett. 70 2134 (1993)] whereby one can express such nonequilibrium quantum impurity models in terms of the system's Lippmann-Schwinger operators. These scattering operators allow one to reformulate the nonequilibrium problem as an effective equilibrium problem associated with a modified Hamiltonian. In this paper, we provide a pedagogical analysis of the core concepts of the effective equilibrium theory. First, we demonstrate the equivalence between observables computed using the Schwinger-Keldysh framework and the effective equilibrium approach, and relate Green's functions in the two theoretical frameworks. Second, we expound some applications of this method in the context of interacting quantum impurity models. We introduce a novel framework to treat effects of interactions perturbatively while capturing the entire dependence on the bias voltage. For the sake of concreteness, we employ the Anderson model as a prototype for this scheme. Working at the particle-hole symmetric point, we investigate the fate of the Abrikosov-Suhl resonance as a function of bias voltage and magnetic field. - Highlights: > Reformulation of steady-state nonequilibrium quantum transport, following Hershfield. > Derivation of effective equilibrium density operator using the 'open-system' approach. > Equivalence with the Keldysh description and formulas relating the two approaches. > Novel framework to treat interactions perturbatively. > Application to nonequilibrium Anderson model and fate of Abrikosov-Suhl resonance.

  11. The equilibrium structure of dark matter halos

    NASA Astrophysics Data System (ADS)

    Busha, Michael Travis

    The far future provides an excellent laboratory for studying cosmological structures. The eventual dominance of the cosmological constant causes the universe to enter a phase of exponential deSitter expansion during which dark matter halos are allowed to relax without interruptions from mass accretion. Using of suite of N-body simulations evolved to scale factor a = 100 in an ?CDM universe, this thesis presents the equilibrium distribution and structure of halos and investigates the importance of mergers in setting the internal halo structure. Using conservation of energy, it is possible to accurately predict the total amount of mass that will ultimately accrete onto a halo. Once this mass is accreted, the halo quickly reaches a state of dynamical equilibrium. Halos in this equilibrium have a greatly simplified radial phase space profile characterized by a single zero-velocity surface that unambiguously defines the halo edge. The radial density profile for such halos is well fit by an NFW profile inside r200, but is steeper at larger radii and better fit by a truncated Hernquist profile. In order to study the importance of hierarchical merging in setting the equilibrium structure, I also present results form AWDM-like simulations with initial power spectra that suppress the early formation of small halos. Using these simulations, I present a modified fit to the mass accretion form of Wechsler et al. (2002) that better characterizes halo growth at all epochs. At the end of the simulations, we recover density profiles and phase space structures that are virtually unchanged between the CDM and WDM cosmologies. The only difference in the global halo properties, a systematic concentration shift, can be characterized in terms of the halo formation epoch, a c. We conclude that mass accretion is not the driving process for setting the equilibrium halo structure.

  12. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands.

    PubMed

    Valente, Luis M; Phillimore, Albert B; Etienne, Rampal S

    2015-08-01

    Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. PMID:26105791

  13. Non-Equilibrium Heavy Flavored Hadron Yields from Chemical Equilibrium Strangeness-Rich QGP

    E-print Network

    Inga Kuznetsova; Johann Rafelski

    2008-01-05

    The yields of heavy flavored hadrons emitted from strangeness-rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.

  14. Data in support of comparative proteomics analysis of superior and inferior spikelets in hybrid rice during grain filling and response of inferior spikelets to drought stress using isobaric tags for relative and absolute quantification

    PubMed Central

    Dong, Minghui; Gu, Junrong; Zhang, Li; Chen, Peifeng; Liu, Tengfei; Deng, Jinhua; Lu, Haoqian; Han, Liyu; Zhao, Buhong

    2014-01-01

    We provide the raw data for protein and peptide identification and quantization of superior and inferior spikelets in hybrid rice during grain filling. The mass spectrometry proteomics data have been deposited to the Proteome Xchange Consortium via the PRIDE partner repository with the dataset identifier PXD001046. Our data presented here is also related to the article “Comparative proteomics analysis of superior and inferior spikelets in hybrid rice during grain filling and response of inferior spikelets to drought stress using isobaric tags for relative and absolute quantification ”in the Journal of Proteomics [1]. PMID:26217686

  15. Adiabatic equilibrium models for direct containment heating

    SciTech Connect

    Pilch, M.M.

    1991-12-31

    PRA studies are being extended to include a wider spectrum of reactor plants than was considered in NUREG-1150. There is a need for computationally simple models for Direct Containment Heating (DCH) that could be used for screening studies aimed at identifying potentially significant contributors to risk. This paper discusses two adiabatic equilibrium models that are candidates for the task. The first, a 1-cell model, places a true upper bound on DCH loads. This upper bound, however, often far exceeds reasonable expectations of containment loads based on best estimate CONTAIN calculations or experiment observations. In this paper, a 2-cell model is developed that largely captures the major mitigating features of containment compartmentalization, thus providing more reasonable estimates of the containment load. Predictions of the equilibrium models are compared with experiment data from the Limited Flight Path (LFP) test series conducted at Sandia National Laboratories.

  16. Adiabatic equilibrium models for direct containment heating

    SciTech Connect

    Pilch, M.M.

    1991-01-01

    PRA studies are being extended to include a wider spectrum of reactor plants than was considered in NUREG-1150. There is a need for computationally simple models for Direct Containment Heating (DCH) that could be used for screening studies aimed at identifying potentially significant contributors to risk. This paper discusses two adiabatic equilibrium models that are candidates for the task. The first, a 1-cell model, places a true upper bound on DCH loads. This upper bound, however, often far exceeds reasonable expectations of containment loads based on best estimate CONTAIN calculations or experiment observations. In this paper, a 2-cell model is developed that largely captures the major mitigating features of containment compartmentalization, thus providing more reasonable estimates of the containment load. Predictions of the equilibrium models are compared with experiment data from the Limited Flight Path (LFP) test series conducted at Sandia National Laboratories.

  17. Cosmic curvature from de Sitter equilibrium cosmology.

    PubMed

    Albrecht, Andreas

    2011-10-01

    I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, ?(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ?(m)(0)/?(?) and the value of the curvature from the initial bubble that starts the inflation, ?(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ?(m)(0)/?(?) and ?(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology. PMID:22107281

  18. Adaptive resolution simulation in equilibrium and beyond

    NASA Astrophysics Data System (ADS)

    Wang, H.; Agarwal, A.

    2015-09-01

    In this paper, we investigate the equilibrium statistical properties of both the force and potential interpolations of adaptive resolution simulation (AdResS) under the theoretical framework of grand-canonical like AdResS (GC-AdResS). The thermodynamic relations between the higher and lower resolutions are derived by considering the absence of fundamental conservation laws in mechanics for both branches of AdResS. In order to investigate the applicability of AdResS method in studying the properties beyond the equilibrium, we demonstrate the accuracy of AdResS in computing the dynamical properties in two numerical examples: The velocity auto-correlation of pure water and the conformational relaxation of alanine dipeptide dissolved in water. Theoretical and technical open questions of the AdResS method are discussed in the end of the paper.

  19. Line radiative transfer and statistical equilibrium

    NASA Astrophysics Data System (ADS)

    Kamp, Inga

    2015-09-01

    Atomic and molecular line emission from protoplanetary disks contains key information of their detailed physical and chemical structures. To unravel those structures, we need to understand line radiative transfer in dusty media and the statistical equilibrium, especially of molecules. I describe here the basic principles of statistical equilibrium and illustrate them through the two-level atom. In a second part, the fundamentals of line radiative transfer are introduced along with the various broadening mechanisms. I explain general solution methods with their drawbacks and also specific difficulties encountered in solving the line radiative transfer equation in disks (e.g. velocity gradients). I am closing with a few special cases of line emission from disks: Radiative pumping, masers and resonance scattering. 9th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  20. Phase Equilibrium Investigations of Planetary Materials

    NASA Technical Reports Server (NTRS)

    Grove, T. L.

    2005-01-01

    This grant provided funds to carry out phase equilibrium studies on the processes of chemical differentiation of the moon and the meteorite parent bodies, during their early evolutionary history. Several experimental studies examined processes that led to the formation of lunar ultramafic glasses. Phase equilibrium studies were carried out on selected low-Ti and high-Ti lunar ultramafic glass compositions to provide constraints on the depth range, temperature and processes of melt generation and/or assimilation. A second set of experiments examined the role of sulfide melts in core formation processes in the earth and terrestrial planets. The major results of each paper are discussed, and copies of the papers are attached as Appendix I.

  1. Equilibrium Reconstruction of KSTAR First Plasma

    NASA Astrophysics Data System (ADS)

    You, K.-I.; Lee, D. K.; Park, B. H.; Lee, S. G.; Bak, J. G.; Seo, S. H.; Hahn, S. H.; Lao, L. L.

    2008-11-01

    To reconstruct the plasma equilibrium of KSTAR (Korea Superconducting Tokamak Advanced Research), we have made some modification to the EFIT code and installed it on our computing system. An MDSplus system is used for the data storage of KSTAR; thus, the EFIT reads experimental data from the MDSplus server and writes the results to it. We have modified some subroutines of the EFIT code for direct link with the MDSplus server. KSTAR PF and TF coil systems use a CICC (Cable-In-Conduit Conductor) type superconductor. The CICC jacket material for most PF and all TF coils is Incoloy 908, which is a magnetic material with relative magnetic permeability greater than 10 in low external field. The Incoloy 908 effects should, therefore, be considered in analyzing the magnetic diagnostics data. In this paper, we present our efforts to reconstruct the plasma equilibrium with EFIT code, including the compensation of Incoloy 908 effects.

  2. Instability of quantum equilibrium in Bohm's dynamics

    PubMed Central

    Colin, Samuel; Valentini, Antony

    2014-01-01

    We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for ‘extended’ non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation. PMID:25383020

  3. Quasilocal equilibrium condition for black ring

    E-print Network

    Dumitru Astefanesei; Maria J. Rodriguez; Stefan Theisen

    2010-04-25

    We use the conservation of the renormalized boundary stress-energy tensor to obtain the equilibrium condition for a general (thin or fat) black ring solution. We also investigate the role of the spatial stress in the thermodynamics of deformation within the quasilocal formalism of Brown and York and discuss the relation with other methods. In particular, we discuss the quantum statistical relation for the unbalanced black ring solution.

  4. Isospin fractionation : equilibrium versus spinodal decomposition

    E-print Network

    Camille Ducoin; Philippe Chomaz; Francesca Gulminelli

    2006-12-21

    This paper focuses on the isospin properties of the asymmetric nuclear-matter liquid-gas phase transition analyzed in a mean-field approach, using Skyrme effective interactions. We compare two different mechanisms of phase separation for low-density matter: equilibrium and spinodal decomposition. The isospin properties of the phases are deduced from the free-energy curvature, which contains information both on the average isospin content and on the system fluctuations. Some implications on experimentally accessible isospin observables are presented.

  5. Multi-period equilibrium/near-equilibrium in electricity markets based on locational marginal prices

    NASA Astrophysics Data System (ADS)

    Garcia Bertrand, Raquel

    In this dissertation we propose an equilibrium procedure that coordinates the point of view of every market agent resulting in an equilibrium that simultaneously maximizes the independent objective of every market agent and satisfies network constraints. Therefore, the activities of the generating companies, consumers and an independent system operator are modeled: (1) The generating companies seek to maximize profits by specifying hourly step functions of productions and minimum selling prices, and bounds on productions. (2) The goals of the consumers are to maximize their economic utilities by specifying hourly step functions of demands and maximum buying prices, and bounds on demands. (3) The independent system operator then clears the market taking into account consistency conditions as well as capacity and line losses so as to achieve maximum social welfare. Then, we approach this equilibrium problem using complementarity theory in order to have the capability of imposing constraints on dual variables, i.e., on prices, such as minimum profit conditions for the generating units or maximum cost conditions for the consumers. In this way, given the form of the individual optimization problems, the Karush-Kuhn-Tucker conditions for the generating companies, the consumers and the independent system operator are both necessary and sufficient. The simultaneous solution to all these conditions constitutes a mixed linear complementarity problem. We include minimum profit constraints imposed by the units in the market equilibrium model. These constraints are added as additional constraints to the equivalent quadratic programming problem of the mixed linear complementarity problem previously described. For the sake of clarity, the proposed equilibrium or near-equilibrium is first developed for the particular case considering only one time period. Afterwards, we consider an equilibrium or near-equilibrium applied to a multi-period framework. This model embodies binary decisions, i.e., on/off status for the units, and therefore optimality conditions cannot be directly applied. To avoid limitations provoked by binary variables, while retaining the advantages of using optimality conditions, we define the multi-period market equilibrium using Benders decomposition, which allows computing binary variables through the master problem and continuous variables through the subproblem. Finally, we illustrate these market equilibrium concepts through several case studies.

  6. Analytical Ultracentrifugation: Sedimentation Velocity and Sedimentation Equilibrium

    PubMed Central

    Cole, James L.; Lary, Jeffrey W.; Moody, Thomas; Laue, Thomas M.

    2009-01-01

    Analytical ultracentrifugation (AUC) is a versatile and powerful method for the quantitative analysis of macromolecules in solution. AUC has broad applications for the study of biomacromolecules in a wide range of solvents and over a wide range of solute concentrations. Three optical systems are available for the analytical ultracentrifuge (absorbance, interference and fluorescence) that permit precise and selective observation of sedimentation in real time. In particular, the fluorescence system provides a new way to extend the scope of AUC to probe the behavior of biological molecules in complex mixtures and at high solute concentrations. In sedimentation velocity, the movement of solutes in high centrifugal fields is interpreted using hydrodynamic theory to define the size, shape and interactions of macromolecules. Sedimentation equilibrium is a thermodynamic method where equilibrium concentration gradients at lower centrifugal fields are analyzed to define molecule mass, assembly stoichiometry, association constants and solution nonideality. Using specialized sample cells and modern analysis software, researchers can use sedimentation velocity to determine the homogeneity of a sample and define whether it undergoes concentration-dependent association reactions. Subsequently, more thorough model-dependent analysis of velocity and equilibrium experiments can provide a detailed picture of the nature of the species present in solution and their interactions. PMID:17964931

  7. Out-of-equilibrium electromagnetic radiation

    E-print Network

    Julien Serreau

    2004-06-22

    We derive general formulas for photon and dilepton production rates from an arbitrary non-equilibrated medium from first principles in quantum field theory. At lowest order in the electromagnetic coupling constant, these relate the rates to the unequal-time in-medium photon polarization tensor and generalize the corresponding expressions for a system in thermodynamic equilibrium. We formulate the question of electromagnetic radiation in real time as an initial value problem and consistently describe the virtual electromagnetic dressing of the initial state. In the limit of slowly evolving systems, we recover known expressions for the emission rates and work out the first correction to the static formulas in a systematic gradient expansion. Finally, we discuss the possible application of recently developed techniques in non-equilibrium quantum field theory to the problem of electromagnetic radiation. We argue, in particular, that the two-particle-irreducible (2PI) effective action formalism provides a powerful resummation scheme for the description of multiple scattering effects, such as the Landau-Pomeranchuk-Migdal suppression recently discussed in the context of equilibrium QCD.

  8. Equilibrium Gold Nanoclusters Quenched with Biodegradable Polymers

    PubMed Central

    Murthy, Avinash K.; Stover, Robert J.; Borwankar, Ameya U.; Nie, Golay D.; Gourisankar, Sai; Truskett, Thomas M.; Sokolov, Konstantin V.; Johnston, Keith P.

    2013-01-01

    Although sub-100 nm nanoclusters of metal nanoparticles are of interest in many fields including biomedical imaging, sensors and catalysis, it has been challenging to control their morphologies and chemical properties. Herein, a new concept is presented to assemble equilibrium Au nanoclusters of controlled size by tuning the colloidal interactions with a polymeric stabilizer, PLA(1k)-b-PEG(10k)-b-PLA(1k). The nanoclusters form upon mixing a dispersion of ~5 nm Au nanospheres with a polymer solution followed by partial solvent evaporation. A weakly adsorbed polymer quenches the equilibrium nanocluster size and provides steric stabilization. Nanocluster size is tuned from ~20 nm to ~40 nm by experimentally varying the final Au nanoparticle concentration and the polymer/Au ratio, along with the charge on the initial Au nanoparticle surface. Upon biodegradation of the quencher, the nanoclusters reversibly and fully dissociate to individual ~5 nm primary particles. Equilibrium cluster size is predicted semi-quantitatively with a free energy model that balances short-ranged depletion and van der Waals attractions with longer-ranged electrostatic repulsion, as a function of the Au and polymer concentrations. The close spacings of the Au nanoparticles in the clusters produce strong NIR extinction over a broad range of wavelengths from 650 to 900 nm, which is of practical interest in biomedical imaging. PMID:23230905

  9. The Equilibrium Structure of Dark Matter Halos

    NASA Astrophysics Data System (ADS)

    Busha, Michael T.; Evrard, A. E.; Adams, F. C.

    2007-07-01

    The far future provides an excellent laboratory for studying cosmological structures. The eventual dominance of the cosmological constant causes the universe to enter a phase of exponential deSitter expansion during which dark matter halos are allowed to relax without interruptions from mass accretion. Halos in equilibrium have a greatly simplified radial phase space profile characterized by a single zero-velocity surface that unambiguously defines the halo edge. Using of suite of N-body simulations evolved to scale factor a = 100 in ?CDM and ?WDM universes, I present the equilibrium structure of halos and investigate the importance of mass accretion in setting this structure. Using these simulations, I present a modified fit to the mass accretion of Wechsler et al. (2002) that better characterizes halo growth at all epochs. At the end of the simulations, we recover density profiles and phase space structures that are virtually unchanged between the CDM and WDM cosmologies. A systematic concentration shift can be characterized in terms of the halo formation epoch, ac. Once substructure effects are removed the phase space distributions are equally unchanged. From this, we conclude that the method of mass accretion is not the driving process in setting the equilibrium halo structure.

  10. BINARY NEUTRON STARS IN QUASI-EQUILIBRIUM

    SciTech Connect

    Taniguchi, Keisuke; Shibata, Masaru

    2010-05-15

    Quasi-equilibrium sequences of binary neutron stars are constructed for a variety of equations of state in general relativity. Einstein's constraint equations in the Isenberg-Wilson-Mathews approximation are solved together with the relativistic equations of hydrostationary equilibrium under the assumption of irrotational flow. We focus on unequal-mass sequences as well as equal-mass sequences, and compare those results. We investigate the behavior of the binding energy and total angular momentum along a quasi-equilibrium sequence, the endpoint of sequences, and the orbital angular velocity as a function of time, changing the mass ratio, the total mass of the binary system, and the equation of state of a neutron star. It is found that the orbital angular velocity at the mass-shedding limit can be determined by an empirical formula derived from an analytic estimation. We also provide tables for 160 sequences, which will be useful as a guideline of numerical simulations for the inspiral and merger performed in the near future.

  11. Radioactive equilibrium in ancient marine sediments

    USGS Publications Warehouse

    Breger, I.A.

    1955-01-01

    Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent-indicating that there is probably equilibrium in all the formations analyzed. Thick-source alpha-particle counting by means of a proportional counter or an ionization chamber leads to high results when the samples contain less than about 10 p.p.m. of uranium. For samples having a higher content of uranium the results are in excellent agreement with each other and with those obtained by direct analytical techniques. The thorium contents that have been obtained correspond well to the average values reported in the literature. The uranium content of marine sediments may be appreciably higher than the average values that have been reported for sedimentary rocks. Data show that there is up to fourteen times the percentage of uranium as of thorium in the formations studied and that the percentage of thorium never exceeds that of uranium. While the proximity of a depositional environment to a land mass may influence the concentration of uranium in a marine sediment, this is not true with thorium. ?? 1955.

  12. Recovery of postural equilibrium control following spaceflight

    NASA Technical Reports Server (NTRS)

    Paloski, W. H.; Reschke, M. F.; Black, F. O.; Doxey, D. D.; Harm, D. L.

    1992-01-01

    Decreased postural stability is observed in most astronauts immediately following spaceflight. Because ataxia may present postflight operational hazards, it is important to determine the incidence of postural instability immediately following landing and the dynamics of recovery of normal postural equilibrium control. It is postulated that postflight postural instability results from in-flight adaptive changes in central nervous system (CNS) processing of sensory information from the visual, vestibular, and proprioceptive systems. The purpose of the present investigation was to determine the magnitude and time course of postflight recovery of postural equilibrium control and, hence, readaptation of CNS processing of sensory information. Thirteen crew members from six spaceflight missions were studied pre- and postflight using a modified commercial posturography system. Postural equilibrium control was found to be seriously disrupted immediately following spaceflight in all subjects. Readaptation to the terrestrial environment began immediately upon landing, proceeded rapidly for the first 10-12 hours, and then proceeded much more slowly for the subsequent 2-4 days until preflight stability levels were reachieved. It is concluded that the overall postflight recovery of postural stability follows a predictable time course.

  13. Bifurcated helical core equilibrium states in tokamaks

    NASA Astrophysics Data System (ADS)

    Cooper, W. A.; Chapman, I. T.; Schmitz, O.; Turnbull, A. D.; Tobias, B. J.; Lazarus, E. A.; Turco, F.; Lanctot, M. J.; Evans, T. E.; Graves, J. P.; Brunetti, D.; Pfefferlé, D.; Reimerdes, H.; Sauter, O.; Halpern, F. D.; Tran, T. M.; Coda, S.; Duval, B. P.; Labit, B.; Pochelon, A.; Turnyanskiy, M. R.; Lao, L.; Luce, T. C.; Buttery, R.; Ferron, J. R.; Hollmann, E. M.; Petty, C. C.; van Zeeland, M.; Fenstermacher, M. E.; Hanson, J. M.; Lütjens, H.

    2013-07-01

    Tokamaks with weak to moderate reversed central shear in which the minimum inverse rotational transform (safety factor) qmin is in the neighbourhood of unity can trigger bifurcated magnetohydrodynamic equilibrium states, one of which is similar to a saturated ideal internal kink mode. Peaked prescribed pressure profiles reproduce the ‘snake’ structures observed in many tokamaks which has led to a novel explanation of the snake as a bifurcated equilibrium state. Snake equilibrium structures are computed in simulations of the tokamak à configuration variable (TCV), DIII-D and mega amp spherical torus (MAST) tokamaks. The internal helical deformations only weakly modulate the plasma-vacuum interface which is more sensitive to ripple and resonant magnetic perturbations. On the other hand, the external perturbations do not alter the helical core deformation in a significant manner. The confinement of fast particles in MAST simulations deteriorate with the amplitude of the helical core distortion. These three-dimensional bifurcated solutions constitute a paradigm shift that motivates the applications of tools developed for stellarator research in tokamak physics investigations.

  14. Side Constrained Traffic Equilibrium Models_ Analysis, Computation and Applications

    E-print Network

    Patriksson, Michael

    convexly side constrained traffic equilibrium assignment m* *odel, and establish several results briefly discuss. Keywords: Traffic Assignment, User Equilibrium, Side Constraints, Generalized. 1 #12; 1 Introduction The mathematical traffic planning tools known as traffic assignment

  15. On the Concept "Chemical Equilibrium": The Associative Framework.

    ERIC Educational Resources Information Center

    Gussarsky, Esther; Gorodetsky, Malka

    1990-01-01

    Word associations were used to map high school students' concepts of "chemical equilibrium" and "equilibrium." It was found that the preconception of the two concepts was differentiated on noncritical dimensions. (Author/CW)

  16. Hanging an Airplane: A Case Study in Static Equilibrium

    ERIC Educational Resources Information Center

    Katz, Debora M.

    2009-01-01

    Our classrooms are filled with engineering majors who take a semester-long course in static equilibrium. Many students find this class too challenging and drop their engineering major. In our introductory physics class, we often breeze through static equilibrium; to physicists equilibrium is just a special case of Newton's second law. While it is…

  17. Side Constrained Traffic Equilibrium Models---Analysis, Computation and Applications

    E-print Network

    Patriksson, Michael

    for refining a descriptive or prescriptive traffic equilibrium assignment model, and analyze a general the users of the network. We study a general convexly side constrained traffic equilibrium assignment model discuss. Keywords: Traffic Assignment, User Equilibrium, Side Constraints, Generalized Wardrop Conditions

  18. On the Problem of Defining Local Thermodynamic Equilibrium

    E-print Network

    On the Problem of Defining Local Thermodynamic Equilibrium H. Roos Institut f¨ur Theoretische what local thermodynamic equilibrium means'', and: ``Nobody has ever given a really satisfactory definition of local thermodynamic equilibrium''. I can defend both of them under suitable conditions; and I

  19. Learning Equilibrium as a Generalization of Learning to Optimize

    E-print Network

    Monderer, Dov

    Learning Equilibrium as a Generalization of Learning to Optimize Dov Monderer and Moshe Tennenholtz, Israel December 2006 Abstract We argue that learning equilibrium is an appropriate generalization and discuss the concept of weak learning equilibrium. 1 Preface In [16], Shoham, Powers, and Grenager (SPG

  20. A non-equilibrium multiscale simulation of shock wave propagation

    E-print Network

    Li, Shaofan

    A non-equilibrium multiscale simulation of shock wave propagation Ni Sheng, Shaofan Li * Department Received 7 August 2007 Available online 4 September 2007 Abstract A novel non-equilibrium multiscale dynamics (NEMSD) is proposed to simulate non-equilibrium thermal­mechanical processes. The model couples

  1. An equilibrium model of insider trading Roberto Monte

    E-print Network

    Ceragioli, Francesca

    An equilibrium model of insider trading Roberto Monte Dipartimento di Studi Economici, Finanziari e - 10129 Torino, ITALY e-mail:barbara.trivellato@polito.it Abstract We study a Bayesian-Nash equilibrium consists in solving a non standard filtering procedure which gives an a priori form for the equilibrium

  2. A NON-EQUILIBRIUM ANALYSIS & CONTROL FRAMEWORK FOR COMMUNICATION NETWORKS

    E-print Network

    Alpcan, Tansu

    A NON-EQUILIBRIUM ANALYSIS & CONTROL FRAMEWORK FOR COMMUNICATION NETWORKS Tansu Alpcan Paul Wang@control.csl.uiuc.edu Abstract: We present a non-equilibrium analysis and control approach for the Active Queue Management (AQM of the complex dynamic queue behavior to show that non-equilibrium methods are essential for analysis

  3. Impact of Mutations on the Allosteric Conformational Equilibrium

    E-print Network

    Sali, Andrej

    Impact of Mutations on the Allosteric Conformational Equilibrium Patrick Weinkam1 , Yao Chi Chen2 at a distant, functional site. In addition to the chemical equilibrium of ligand binding, allostery involves a conformational equilibrium between one protein substate that binds the effector and a second substate that less

  4. Equilibrium shape degeneracy in starfish vesicles Xavier Michalet*

    E-print Network

    Michalet, Xavier

    Equilibrium shape degeneracy in starfish vesicles Xavier Michalet* Chemistry & Biochemistry a few hundred nanometers to few tens of micrometers. The equilibrium shapes of these vesicles are well of equilibrium shapes of closed fluid bilayer membranes also referred to as vesicles or liposomes has been

  5. EQUILIBRIUM SHAPE CONTROL IN CIT PF DESIGN* D. J. Strickler

    E-print Network

    EQUILIBRIUM SHAPE CONTROL IN CIT PF DESIGN* D. J. Strickler Fusion Engineering Design Center, Oak Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08544 ABSTRACT The free-boundary equilibrium code VEQ provides equilibrium data that are used by the Tokamak Simulation Code (TSC) in design

  6. The Equilibrium Point Hypothesis for Control of Movements Reza Shadmehr

    E-print Network

    Shadmehr, Reza

    The Equilibrium Point Hypothesis for Control of Movements Reza Shadmehr Dept. of Biomedical guration is the equilibrium point of the system. If we now change the length-tension properties of the rubber bands, for example, change the resting lengths or sti nesses, the equilibrium point of the system

  7. Non-equilibrium Chemistry in Brown Dwarf Atmospheres

    E-print Network

    Metchev, Stanimir

    Non-equilibrium Chemistry in Brown Dwarf Atmospheres PHY688 Aaron Jackson April 27, 2009 #12;Outline What is non-equilibrium chemistry in the context of Brown Dwarfs? What is the observational signature of non- equilibrium chemistry? What are the relevant timescales? Modelling vertical transport

  8. EQUILIBRIUM PATHS OF MECHANICAL SYSTEMS WITH UNILATERAL CONSTRAINTS

    E-print Network

    Pellegrino, Sergio

    EQUILIBRIUM PATHS OF MECHANICAL SYSTEMS WITH UNILATERAL CONSTRAINTS PART II: DEPLOYABLE REFLECTOR M, by imple- menting the theory for tracing the equilibrium path of a mechanical system with unilateral had not been previously explained, is the existence of a corner limit point on the equilibrium path

  9. http://w3.pppl.gov/~zakharov Equilibrium

    E-print Network

    Zakharov, Leonid E.

    web page: http://w3.pppl.gov/~zakharov Equilibrium reconstruction of q­ and p­ profiles in ITER sets of external and internal measurements envisioned for equilibrium reconstruction in ITER widely used equilibrium reconstruction technique. Leonid E. Zakharov, Conference on Diagnostics of High

  10. Equilibrium existence and uniqueness in impure public good models

    E-print Network

    Kotchen, Matthew J.

    Equilibrium existence and uniqueness in impure public good models Matthew J. Kotchen 4420 Donald to the model's equilibrium properties. This paper presents a proof that clearly shows sufficient conditions for existence and uniqueness of a Nash equilibrium. © 2007 Elsevier B.V. All rights reserved. Keywords: Impure

  11. Equilibrium of highly asymmetric non-neutral plasmas J. Fajansa)

    E-print Network

    McCarthy, John E.

    Equilibrium of highly asymmetric non-neutral plasmas J. Fajansa) and E. Yu. Backhaus Department of these plasmas. Wall potentials can be found which place many asymmetric, flat-top plasmas into exact equilibrium; virtually any flat-top plasma can be placed into approximate equilibrium. © 1999 American Institute

  12. http://w3.pppl.gov/~zakharov equilibrium

    E-print Network

    Zakharov, Leonid E.

    web page: http://w3.pppl.gov/~zakharov The theory of equilibrium reconstruction and a possibility measurements envisioned for equilibrium recon­ struction in ITER. It was shown that complementing the external had a signifi­ cant gap in ability to evaluate the quality of the presently widely used equilibrium

  13. Investigating High School Students' Understanding of Chemical Equilibrium Concepts

    ERIC Educational Resources Information Center

    Karpudewan, Mageswary; Treagust, David F.; Mocerino, Mauro; Won, Mihye; Chandrasegaran, A. L.

    2015-01-01

    This study investigated the year 12 students' (N = 56) understanding of chemical equilibrium concepts after instruction using two conceptual tests, the "Chemical Equilibrium Conceptual Test 1" ("CECT-1") consisting of nine two-tier multiple-choice items and the "Chemical Equilibrium Conceptual Test 2"…

  14. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Ear, nose, throat, and equilibrium. 67.205... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class...

  15. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Ear, nose, throat, and equilibrium. 67.305... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class...

  16. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.305... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class...

  17. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Ear, nose, throat, and equilibrium. 67.205... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class...

  18. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.105... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class...

  19. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Ear, nose, throat, and equilibrium. 67.105... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class...

  20. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.105... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class...

  1. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Ear, nose, throat, and equilibrium. 67.305... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class...

  2. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.205... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class...

  3. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.305... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class...

  4. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Ear, nose, throat, and equilibrium. 67.205... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class...

  5. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Ear, nose, throat, and equilibrium. 67.105... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class...

  6. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Ear, nose, throat, and equilibrium. 67.305... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Third-Class Airman Medical Certificate § 67.305 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class...

  7. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Ear, nose, throat, and equilibrium. 67.105... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION First-Class Airman Medical Certificate § 67.105 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class...

  8. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Ear, nose, throat, and equilibrium. 67.205... (CONTINUED) AIRMEN MEDICAL STANDARDS AND CERTIFICATION Second-Class Airman Medical Certificate § 67.205 Ear, nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class...

  9. Eulerian and Lagrangian pictures of non-equilibrium diffusions

    E-print Network

    Raphael Chetrite; Krzysztof Gawedzki

    2009-05-28

    We show that a non-equilibrium diffusive dynamics in a finite-dimensional space takes in the Lagrangian frame of its mean local velocity an equilibrium form with the detailed balance property. This explains the equilibrium nature of the fluctuation-dissipation relations in that frame observed previously. The general considerations are illustrated on few examples of stochastic particle dynamics.

  10. Towards breaking temperature equilibrium in multi-component Eulerian schemes

    SciTech Connect

    Grove, John W; Masser, Thomas

    2009-01-01

    We investigate the effects ofthermal equilibrium on hydrodynamic flows and describe models for breaking the assumption ofa single temperature for a mixture of components in a cell. A computational study comparing pressure-temperature equilibrium simulations of two dimensional implosions with explicit front tracking is described as well as implementation and J-D calculations for non-equilibrium temperature methods.

  11. Nonequilibrium Capillary Electrophoresis of Equilibrium Mixtures -A Single Experiment Reveals Equilibrium and Kinetic Parameters of Protein-DNA

    E-print Network

    Krylov, Sergey

    into the capillary and subjected to electrophoresis under nonequilibrium conditions. The new method allowsNonequilibrium Capillary Electrophoresis of Equilibrium Mixtures - A Single Experiment Reveals method, nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM), and describe its use

  12. Evaluation of equilibrium and non-equilibrium evaporation models for many-droplet gas-liquid ow simulations

    E-print Network

    Miller, Richard S.

    ±Knudsen law and a corrected (for evaporation eects) analytical heat transfer expression derived from the quasiEvaluation of equilibrium and non-equilibrium evaporation models for many-droplet gas-liquid ¯ow Abstract A variety of liquid droplet evaporation models, including both classical equilibrium and non

  13. A Case where a Paradox Like Braess's Occurs in the Nash Equilibrium but Does Not Occur in the Wardrop Equilibrium

    E-print Network

    A Case where a Paradox Like Braess's Occurs in the Nash Equilibrium but Does Not Occur in the Wardrop Equilibrium ¯ A Situation of Load Balancing in Distributed Computer Systems ¯ Hisao Kameda \\Lambda of the other individuals. Another framework in which such a paradox may occur is that of the Nash equilibrium

  14. Non-Equilibrium Fluctuation-Dissipation Inequality and Non-Equilibrium Uncertainty Principle

    E-print Network

    C. H. Fleming; B. L. Hu; Albert Roura

    2010-12-03

    The fluctuation-dissipation relation is usually formulated for a system interacting with a heat bath at finite temperature in the context of linear response theory, where only small deviations from the mean are considered. We show that for an open quantum system interacting with a non-equilibrium environment, where temperature is no longer a valid notion, a fluctuation-dissipation inequality exists. Clearly stated, quantum fluctuations are bounded below by quantum dissipation, whereas classically the fluctuations can be made to vanish. The lower bound of this inequality is exactly satisfied by (zero-temperature) quantum noise and is in accord with the Heisenberg uncertainty principle, both in its microscopic origins and its influence upon systems. Moreover, it is shown that the non-equilibrium fluctuation-dissipation relation determines the non-equilibrium uncertainty relation in the weak-damping limit.

  15. Diffusion and thermodynamic equilibrium under pressure variations

    NASA Astrophysics Data System (ADS)

    Moulas, Evangelos; Taj?manová, Lucie; Vrijmoed, Johannes; Podladchikov, Yuri

    2015-04-01

    Pressure is one of the most fundamental variables in mineral thermodynamics. In that respect, pressure-sensitive mineral reactions provide an important constraint on pressure under which the rock was developed. One implicit assumption when interpreting such pressure estimates is that the state-of-stress is close to hydrostatic, homogeneous and that the differential stress is negligible. Recent spectroscopic data from the mineral scale documenting pressure variations do not support this assumption. In addition to observations, mechanical models (numerical and analytical) suggest that rocks can develop and maintain heterogeneous pressure distributions at geological time scales. The recently developed unconventional barometry explains chemical zoning in minerals as a result of a pressure variation. We focus to apply the unconventional barometry in cases where chemical zoning in minerals cannot be explained by sluggish kinetics. In that respect, the unconventional barometry offers an alternative view of the chemical zoning which is consistent with thermodynamic equilibrium. However, to distinguish between a pressure-controlled chemical zoning and a zoning reflecting an incomplete chemical reaction is still challenging, especially for multicomponent systems. In this contribution, different types of chemical zoning are discussed. We investigate plagioclase rims around kyanite from an amphibolitized eclogite from Rhodope Metamorphic Complex (Greece-Bulgaria) as a case study and compare them with similar published textures from the Bohemian Massif. Mineral microstructures and phase equilibrium suggest that both rocks experienced near-isothermal decompression at high (>700C) temperatures. However, several distinct microstructural features suggest the development and/or the decay of mechanically maintained heterogeneous pressure distributions. We discuss our results and interpretations based on phase-equilibrium modeling, unconventional barometry and diffusion modeling under pressure variations.

  16. Equilibrium defects and concentrations in nickel aluminide

    SciTech Connect

    Bai, B.; Collins, G.S.

    1999-07-01

    Perturbed angular correlation of gamma rays was applied to determine properties of equilibrium defects in B2 NiAl near the stoichiometric composition. Point defects were detected through quadrupole interactions they induce at In probe atoms on the Al sublattice. Well-resolved signals were observed for probe atoms having zero, one or two Ni-vacancies (V{sub Ni}) in the first neighbor shell. The fractions of probes in different sites are analyzed using a thermodynamic model to determine defect properties as follows. The equilibrium high-temperature defect is determined to be the triple defect combination (two V{sub Ni} and one Ni-antisite atom) through the variation of the vacancy concentration with composition and not, for example, the Schottky vacancy pair. The binding enthalpy of V{sub Ni} with a probe atom was determined to be in the range 0.18--0.24 eV. Site fractions were measured for three samples having 50.03, 50.14 and 50.91 at.% Ni at temperatures up to 1300 C. Vacancy concentrations were deduced from the site fractions and binding enthalpy. The equilibrium constant for formation of the triple defect was determined as a function of temperature from the vacancy concentrations and sample compositions. The formation enthalpy was found to be in the range 1.65--1.83 eV, depending on the binding enthalpy. The formation entropy was found to be {minus}3.2(4)k{sub B}. The large, negative value of the formation entropy probably cannot be explained in terms of a binding entropy, and the authors speculate that triple defects harden the B2 lattice, perhaps by disrupting the well-known 1/3 {l{underscore}angle}111{r{underscore}angle} soft mode lattice instability in B2 and bcc materials.

  17. Multicomponent Equilibrium Models for Testing Geothermometry Approaches

    SciTech Connect

    Cooper, D. Craig; Carl D. Palmer; Robert W. Smith; Travis L. McLing

    2013-02-01

    Geothermometry is an important tool for estimating deep reservoir temperature from the geochemical composition of shallower and cooler waters. The underlying assumption of geothermometry is that the waters collected from shallow wells and seeps maintain a chemical signature that reflects equilibrium in the deeper reservoir. Many of the geothermometers used in practice are based on correlation between water temperatures and composition or using thermodynamic calculations based a subset (typically silica, cations or cation ratios) of the dissolved constituents. An alternative approach is to use complete water compositions and equilibrium geochemical modeling to calculate the degree of disequilibrium (saturation index) for large number of potential reservoir minerals as a function of temperature. We have constructed several “forward” geochemical models using The Geochemist’s Workbench to simulate the change in chemical composition of reservoir fluids as they migrate toward the surface. These models explicitly account for the formation (mass and composition) of a steam phase and equilibrium partitioning of volatile components (e.g., CO2, H2S, and H2) into the steam as a result of pressure decreases associated with upward fluid migration from depth. We use the synthetic data generated from these simulations to determine the advantages and limitations of various geothermometry and optimization approaches for estimating the likely conditions (e.g., temperature, pCO2) to which the water was exposed in the deep subsurface. We demonstrate the magnitude of errors that can result from boiling, loss of volatiles, and analytical error from sampling and instrumental analysis. The estimated reservoir temperatures for these scenarios are also compared to conventional geothermometers. These results can help improve estimation of geothermal resource temperature during exploration and early development.

  18. Cylindrical equilibrium shapes of fluid membranes

    E-print Network

    V. M. Vassilev; P. A. Djondjorov; I. M. Mladenov

    2009-10-22

    Within the framework of the well-known curvature models, a fluid lipid bilayer membrane is regarded as a surface embedded in the three-dimensional Euclidean space whose equilibrium shapes are described in terms of its mean and Gaussian curvatures by the so-called membrane shape equation. In the present paper, all solutions to this equation determining cylindrical membrane shapes are found and presented, together with the expressions for the corresponding position vectors, in explicit analytic form. The necessary and sufficient conditions for such a surface to be closed are derived and several sufficient conditions for its directrix to be simple or self-intersecting are given.

  19. Equilibrium charge distribution on annealed polyelectrolytes.

    PubMed

    Zito, T; Seidel, C

    2002-06-01

    Monte Carlo simulations are used to study the non-uniform equilibrium charge distribution along a single annealed polyelectrolyte chain under theta solvent conditions and with added salt. Within a range of the order of the Debye length charge accumulates at chain ends while a slight charge depletion appears in the central part of the chain. The simulation results are compared with theoretical predictions recently given by Castelnovo et al. In the parameter range where the theory can be applied we find almost perfect quantitative agreement. PMID:15010956

  20. Adaptive Implicit Non-Equilibrium Radiation Diffusion

    SciTech Connect

    Philip, Bobby; Wang, Zhen; Berrill, Mark A; Rodriguez Rodriguez, Manuel; Pernice, Michael

    2013-01-01

    We describe methods for accurate and efficient long term time integra- tion of non-equilibrium radiation diffusion systems: implicit time integration for effi- cient long term time integration of stiff multiphysics systems, local control theory based step size control to minimize the required global number of time steps while control- ling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton-Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent solver convergence.