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1

Isobaric vapor-liquid equilibrium for methyldichlorosilane-dimethyldichlorosilane-benzene system*  

PubMed Central

The elucidation of vapor-liquid equilibrium (VLE) of the halogenated silane was necessary for the production of silicon derivatives, especially for methylvinyldichlorosilane, due to the lack of the relevant reports. Isobaric VLE for the system methyldichlorosilane-dimethyldichlorosilane-benzene and isobaric VLE of the three binary systems were measured with a new pump-ebulliometer at the pressure of 101.325 kPa. These binary compositions of the equilibrium vapor were calculated according to the Q function of molar excess Gibbs energy by the indirect method and the resulted VLE data agreed well with the thermodynamic consistency. Moreover, the experimental data were correlated with the Wilson, NRTL, Margules and van Laar equations by means of the least-squares fit, the acquired optimal interaction parameters were fitted to experimental vapor-liquid equilibrium data for binary systems. The binary parameters of Wilson equation were also used to calculate the bubble point temperature and the vapor phase composition for the ternary mixtures without any additional adjustment. The predicted vapor-liquid equilibrium for the ternary system was in a good agreement with the experimental results. The VLE of binary and multilateral systems provided essential theory for the production of the halogenated silane. PMID:16187419

Qiu, Zu-min; Xie, Xin-liang; Yu, Shu-xian; Chen, Wen-you; Xie, Feng-xia; Liu, Juan

2005-01-01

2

Isobaric vapor-liquid equilibrium for methyldichlorosilane-dimethyldichlorosilane-benzene system.  

PubMed

The elucidation of vapor-liquid equilibrium (VLE) of the halogenated silane was necessary for the production of silicon derivatives, especially for methylvinyldichlorosilane, due to the lack of the relevant reports. Isobaric VLE for the system methyldichlorosilane-dimethyldichlorosilane-benzene and isobaric VLE of the three binary systems were measured with a new pump-ebulliometer at the pressure of 101.325 kPa. These binary compositions of the equilibrium vapor were calculated according to the Q function of molar excess Gibbs energy by the indirect method and the resulted VLE data agreed well with the thermodynamic consistency. Moreover, the experimental data were correlated with the Wilson, NRTL, Margules and van Laar equations by means of the least-squares fit, the acquired optimal interaction parameters were fitted to experimental vapor-liquid equilibrium data for binary systems. The binary parameters of Wilson equation were also used to calculate the bubble point temperature and the vapor phase composition for the ternary mixtures without any additional adjustment. The predicted vapor-liquid equilibrium for the ternary system was in a good agreement with the experimental results. The VLE of binary and multilateral systems provided essential theory for the production of the halogenated silane. PMID:16187419

Qiu, Zu-Min; Xie, Xin-Liang; Yu, Shu-Xian; Chen, Wen-You; Xie, Feng-Xia; Liu, Juan

2005-10-01

3

Isobaric vapor–liquid equilibria for ethanol–water system containing different ionic liquids at atmospheric pressure  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for ethanol–water systems containing ionic liquids (ILs) 1-methyl-3-methylimidazolium dimethylphosphate ([MMIM][DMP]), 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][DEP]), 1-butyl-3-methylimidazolium bromide ([BMIM][Br]), 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) at atmospheric pressure (101.32kPa) were measured with a circulation still. The results showed that the VLE of ethanol–water systems in the presence of different ILs was obviously different from that of the

Jin Zhao; Cong-Cong Dong; Chun-Xi Li; Hong Meng; Zi-Hao Wang

2006-01-01

4

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

E-print Network

) were used to describe the properties of the pure substances. The vapor pressures of water and carbonVAPOR + 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

5

Effects of vapor-liquid equilibrium on wetting efficiency in hydrodesulfurization trickle-bed reactors  

E-print Network

EFFECTS OF VAPOR-LIQUID EQUILIBRIUM ON WETTING EFFICIENCY IN HYDRODESULFURIZATION TRICKLE-BED REACTORS A Thesis by ANNA LISA MILLS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE December 1988 Major Subject: Chemical Engineering EFFECTS OF VAPOR-LIQUID EQUILIBRIUM ON WETTING EFFICIENCY IN HYDRODESULFURIZATION TRICKLE-BED REACTORS A Thesis by ANNA LISA MILLS Approved as to style and content by...

Mills, Anna Lisa

2012-06-07

6

Recommended Vapor-Liquid Equilibrium Data. Part 2: Binary Alkanol-Alkane Systems  

NASA Astrophysics Data System (ADS)

The recommended vapor-liquid equilibrium (VLE) data for 36 binary systems involving primary, secondary, and tertiary alcohols with n-alkanes and isoalkanes [with the exception of 1-alkanols-n-alkane systems, which were presented in Part 1 of this series—J. Phys. Chem. Ref. Data 31(3), 702 (2002)] have been obtained after critical evaluation of all data (744 data sets) reported in the open literature up to the middle of 2002. The evaluation procedure consisted in combining the thermodynamic consistency tests, data correlation, comparison with enthalpy of mixing data, and comparison of VLE data for various mixtures. The data were correlated with equations based on local compositions concept as well as with equation of state appended with chemical term (EoSC) proposed by Góral. The recommended data are presented in the form of sheets containing tables of data, figures and auxiliary information. Each sheet corresponds to one system and contains three isotherms (spaced by at least 15 K) and one isobar (preferably at 101.32 kPa). Experimental gaps were completed with the predicted data.

Góral, Marian; Oracz, Pawe?; Skrzecz, Adam; Bok, Andrzej; Ma̧czy?ski, Andrzej

2003-12-01

7

Vapor-liquid equilibrium of mixtures formed by methanol, 2-propanol, and chlorobenzene  

SciTech Connect

Isothermal vapor-liquid equilibrium data at 55/sup 0/C are presented for the binary system 2-propanol-chlorobenzene and the ternary system methanol-2-propanol-chlorobenzene. The experimental results are well correlated with the UNIQUAC associated-solution theory with binary parameters obtained from the maximum likelihood principle.

Nagata, I.

1986-10-01

8

Modeling high-pressure vapor–liquid equilibrium of limonene, linalool and carbon dioxide systems  

Microsoft Academic Search

The research reported in this study is focused on modeling high-pressure phase behavior for CO2–limonene and CO2–linalool. A modified Peng–Robinson equation of state was applied to calculate vapor–liquid equilibrium using five different mixing rules obtained by incorporating activity coefficient models. The methodologies proposed by Heidemann–Kokal, Wong–Sandler and LCVM were used coupled with NRTL, UNIQUAC and UNIFAC models. A comparative analysis

S. A. B Vieira de Melo; G. M. N Costa; A. M. C Uller; F. L. P Pessoa

1999-01-01

9

Condensation coefficient of methanol vapor near vapor-liquid equilibrium states  

NASA Astrophysics Data System (ADS)

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.

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

10

Testing the recent charge-on-spring type polarizable water models. II. Vapor-liquid equilibrium  

NASA Astrophysics Data System (ADS)

We studied the vapor-liquid coexistence region of seven molecular models of water. All models use the charge-on-spring (COS) method to express polarization. The studied models were the COS/G2, COS/G3 [H. Yu and W. F. van Gunsteren, J. Chem. Phys. 121, 9549 (2004), 10.1063/1.1805516], the SWM4-DP [G. Lamoureux, A. D. MacKerell, Jr., and B. Roux, J. Chem. Phys. 119, 5185 (2003), 10.1063/1.1598191], the SWM4-NDP [G. Lamoureux, E. Harder, I. V. Vorobyov, B. Roux, and A. D. MacKerell, Jr., Chem. Phys. Lett. 418, 245 (2006), 10.1016/j.cplett.2005.10.135], and three versions of our model, the BKd1, BKd2, and BKd3. The BKd1 is the original Gaussian model [P. T. Kiss, M. Darvas, A. Baranyai, and P. Jedlovszky, J. Chem. Phys. 136, 114706 (2012), 10.1063/1.3692602] with constant polarization and with a simple exponential repulsion. The BKd2 applies field-dependent polarizability [A. Baranyai and P. T. Kiss, J. Chem. Phys. 135, 234110 (2011), 10.1063/1.3670962], while the BKd3 model has variable size to approximate the temperature-density (T-?) curve of water [P. T. Kiss and A. Baranyai, J. Chem. Phys. 137, 194102 (2012), 10.1063/1.4767063]. We calculated the second virial coefficient, the heat of vaporization, equilibrium vapor pressure, the vapor-liquid coexistence curve, and the surface tension in terms of the temperature. We determined and compared the critical temperatures, densities, and pressures of the models. We concluded that the high temperature slope of the (T-?) curve accurately predicts the critical temperature. We found that Gaussian charge distributions have clear advantages over the point charges describing the critical region. It is impossible to describe the vapor-liquid coexistence properties consistently with nonpolarizable models, even if their critical temperature is correct.

Kiss, Péter T.; Baranyai, András

2012-11-01

11

Isobaric vapor–liquid equilibria for mixtures of tetrahydrofuran, 2-propanol, and 2,2,4-trimethylpentane at 101.3 kPa  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) at 101.3kPa have been determined for a ternary system (tetrahydofuran+2-propanol+2,2,4-trimethylpentane) and its constituent binary systems (tetrahydrofuran+2-propanol, tetrahydrofuran+2,2,4-trimethylpentane, and 2-propanol+2,2,4-trimethylpentane). The activity coefficients of liquid mixtures were calculated from the modified Raoult's law. Thermodynamic consistency tests were performed for all VLE data. The VLE data of the binary mixtures and ternary mixtures were correlated using the Margules, Wilson,

Chia-Chiang Hsu; Chein-Hsiun Tu

2008-01-01

12

Acid Gas - Diethanolamine Vapor - Liquid Equilibrium Data by Fourier Transform Infrared Spectroscopy.  

NASA Astrophysics Data System (ADS)

A new apparatus for establishing vapor-liquid equilibrium (VLE) and a new method for measuring VLE data on acid gas - diethanolamine (DEA) systems are described. The acid gases studied were carbon dioxide (CO_2 ) and hydrogen sulfide (H_2S). The capability of the apparatus to establish an equilibrium was verified by reproducing data for CO_ {2}-water and H_2S -water systems. The new measurement method used Fourier transform infrared (FTIR) spectroscopy to analyze the gas composition without removing a vapor sample from the equilibrium equipment. Gas chromatography was used to analyze the liquid phase. The FTIR method eliminated the typical adsorption losses and subsequent errors resulting from the sampling and analysis of vapor compositions with low concentrations of hydrogen sulfide. Using the new method, preliminary VLE measurements have been made for a previously determined system using a single acid gas and an acid gas mixture over a 20 wt % DEA solution at 50^circ C. The CO_2 only system was measured over the partial pressure range of 0.1 to 0.0002 psia and liquid loadings from 0.2 to 0.008 moles of CO_2 per mole of DEA. The H _2S only system was measured over the partial pressure range from 0.8 psia to the lower limit of 0.01 psia and liquid loadings from 0.32 to 0.001 moles of H_2S per mole of DEA. Low partial pressure H_2S measurements deviated from literature VLE data and indicated that the equipment or methodology still needs to be refined. Acid gas mixture measurements were also incorrect but do illustrate that the method is viable for analyzing mixed acid gases and can surpass published, contemporary, VLE measurements determined by gas chromatography only. FTIR analysis of the liquid phase for ionic species was indeterminate. This work is the first stage in a continuing research effort. Equipment modifications are recommended to improve the lower detectable limit for hydrogen sulfide and carbon dioxide partial pressure measurements, to define a quantitative FTIR liquid analysis method, to compare the FTIR method with gas chromatographic determined data, and to study other acid gas-alkanolamine systems.

Frazier, Richard Eugene

13

Vapor-Liquid Equilibrium in the Mixture Propenenitrile C3H3N + C6H5Cl Chlorobenzene (EVLM1211, LB5649_E)  

NASA Astrophysics Data System (ADS)

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 Propenenitrile C3H3N + C6H5Cl Chlorobenzene (EVLM1211, LB5649_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

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

14

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

SciTech Connect

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.

Henry, R. M.

1980-10-01

15

Collection of VLE data for acid gas---alkanolamine systems using fourier transform infrared spectroscopy. [Vapor-liquid equilibrium  

SciTech Connect

The industrial standard process for the purification of natural gas is to remove acid gases, mainly hydrogen sulfide and carbon dioxide, by the absorption and reaction of these gases with alkanolamines. Inadequate data for vapor--liquid equilibrium (VLE) hinder the industry from converting operations to more energy efficient amine mixtures and conserving energy. Some energy reductions have been realized in the past decade by applying such amine systems as hindered'' amines, methyldiethanolamine (MDEA), and MDEA based amine mixtures. However, the lack of reliable and accurate fundamental VLE data impedes the commercial application of these more efficient alkanolamine systems. The first project objective is to improve the accuracy of vapor--liquid equilibrium measurements at low hydrogen sulfide concentrations. The second project objective is to measure the VLE for amine mixtures. By improving the accuracy of the VLE measurements on MDEA and mixtures with other amines, energy saving can be quickly and confidently implemented in the many existing absorption units already in use. If about 25% of the existing 95.3 billion SCFD gas purification capacity is converted to these new amine systems, the energy savings are estimated to be about 3 [times] 10[sup 14] BTU/yr.

Bullin, J.A.; Frazier, R.E.

1992-01-01

16

New phase equilibrium analyzer for determination of the vapor-liquid equilibrium of carbon dioxide and permanent gas mixtures for carbon capture and storage  

NASA Astrophysics Data System (ADS)

A high-pressure, phase equilibrium analyzer incorporating a fiber-optic reflectometer is described. The analyzer has been designed for measuring the vapor-liquid equilibrium data of multi-component mixtures of carbon dioxide and permanent gases, providing a novel tool to acquire of a large number of phase equilibrium data for the development of the new carbon capture and storage technologies. We demonstrate that the analyzer is suitable for determining both the bubble- and dew-point lines at temperature from 253 K and pressure up to 25 MPa using pure CO2 and two binary mixtures of CO2 + N2 and CO2 + H2.

Ke, Jie; Parrott, Andrew J.; Sanchez-Vicente, Yolanda; Fields, Peter; Wilson, Richard; Drage, Trevor C.; Poliakoff, Martyn; George, Michael W.

2014-08-01

17

New phase equilibrium analyzer for determination of the vapor-liquid equilibrium of carbon dioxide and permanent gas mixtures for carbon capture and storage.  

PubMed

A high-pressure, phase equilibrium analyzer incorporating a fiber-optic reflectometer is described. The analyzer has been designed for measuring the vapor-liquid equilibrium data of multi-component mixtures of carbon dioxide and permanent gases, providing a novel tool to acquire of a large number of phase equilibrium data for the development of the new carbon capture and storage technologies. We demonstrate that the analyzer is suitable for determining both the bubble- and dew-point lines at temperature from 253 K and pressure up to 25?MPa using pure CO2 and two binary mixtures of CO2 + N2 and CO2 + H2. PMID:25173315

Ke, Jie; Parrott, Andrew J; Sanchez-Vicente, Yolanda; Fields, Peter; Wilson, Richard; Drage, Trevor C; Poliakoff, Martyn; George, Michael W

2014-08-01

18

Vapor-Liquid Equilibrium in the Mixture Dimethyl sulfoxide C2H6OS + C6H5Cl Chlorobenzene (EVLM1211, LB5641_E)  

NASA Astrophysics Data System (ADS)

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 Dimethyl sulfoxide C2H6OS + C6H5Cl Chlorobenzene (EVLM1211, LB5641_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

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

19

Vapor-Liquid Equilibrium of the Mixture Cl4Si + C3H9ClSi (LB5010, EVLM 1231)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A2 `Binary Liquid Systems of Nonelectrolytes, Part 2' of Volume 13 `Vapor-Liquid Equilibrium in Mixtures and Solutions' of Landolt-Börnstein Group IV `Physical Chemistry'. It corresponds to the entry LB5010 of the Print Version and the ELBT Database, respectively.

Wichterle, I.; Linek, J.; Wagner, Z.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

20

Vapor-Liquid Equilibrium of the Mixture CH3Cl3Si + C3H9ClSi (LB5008, EVLM 1231)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A2 `Binary Liquid Systems of Nonelectrolytes, Part 2' of Volume 13 `Vapor-Liquid Equilibrium in Mixtures and Solutions' of Landolt-Börnstein Group IV `Physical Chemistry'. It corresponds to the entry LB5008 of the Print Version and the ELBT Database, respectively.

Wichterle, I.; Linek, J.; Wagner, Z.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

21

Vapor-Liquid Equilibrium of the Mixture C2H6Cl2Si + C3H9ClSi (LB5006, EVLM 1231)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A2 `Binary Liquid Systems of Nonelectrolytes, Part 2' of Volume 13 `Vapor-Liquid Equilibrium in Mixtures and Solutions' of Landolt-Börnstein Group IV `Physical Chemistry'. It corresponds to the entry LB5006 of the Print Version and the ELBT Database, respectively.

Wichterle, I.; Linek, J.; Wagner, Z.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

22

Molecular Dynamics Study of Vapor-Liquid Equilibrium State of an Argon Nanodroplet and Its Vapor  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) study of equilibrium system of a single argon nanodroplet and its surrounding argon vapor is carried out to address a fundamental issue whether the thermodynamic description is applicable to the nanoscale inhomogeneous system. The numerical result is sufficiently reliable so that it can identify the smallest droplet standing stably over 200 ns. The validity of the Laplace equation for nanodroplet is proved by a purely mechanical argument on the basis of directly computed normal and tangential pressures in the transition layer. Furthermore, it is demonstrated that the chemical potentials of liquid and vapor phases are not equal when a droplet is so small that the number of molecules consisting the transition layer may be comparable to that in the droplet. The Kelvin equation does not hold in such a case.

Yaguchi, Hisao; Yano, Takeru; Fujikawa, Shigeo

23

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

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).

Betts, S.E. [California Univ., Santa Barbara, CA (United States)

1993-10-01

24

Vapor-liquid equilibria of 1-propanol or 2-propanol with 2,2,4-trimethylpentane at 101. 3 kPa  

Microsoft Academic Search

Isobaric vapor-liquid equilibria were measured for 1-propanol or 2-propanol with 2,2,4-trimethylpentane at 101.3 kPa in an equilibrium still with circulation of both the vapor and liquid phases. The results were best correlated with the Wilson equation. The equilibrium composition of the samples was determined using a Shimadzu gas chromatography. The accuracy of liquid, x[sub i], and vapor, y[sub i], mole

Toshihiko Hiaki; Kenji Takahashi; Tomoya Tsuji; Masaru Hongo; Kazuo Kojima

1994-01-01

25

Vapor-liquid equilibria for the binary systems of 1-butanol with some halohydrocarbons at 40.0 and 101.3 kPa  

SciTech Connect

Isobaric vapor-liquid equilibrium measurements at 40.0 and 101.3 kPa are reported for 1-butanol + chlorocyclohexane, + chlorobenzene, + bromocyclohexane, + bromobenzene. Some of the studied systems show minimum temperature azeotropes. The experimental data were tested for thermodynamic consistency and satisfactorily correlated with the Margules, Van Laar, Wilson, NRTL, and UNIQUAC equations. Predictions with the UNIFAC method and ASOG method were also obtained.

Artigas, H.; Lafuente, C.; Cea, P.; Royo, F.M.; Urieta, J.S. [Univ. de Zaragoza (Spain)] [Univ. de Zaragoza (Spain)

1997-01-01

26

Vapor–liquid equilibrium for binary system of tetrahydrothiophene + 2,2,4-trimethylpentane and tetrahydrothiophene + 2,4,4-trimethyl-1-pentene at 358.15 and 368.15 K  

Microsoft Academic Search

Isothermal vapor–liquid equilibrium (VLE) for tetrahydrothiophene+2,2,4-trimethylpentane and tetrahydrothiophene+2,4,4-trimethyl-1-pentene at 358.15 and 368.15K were measured with a circulation still. All systems studied exhibit positive deviation from Raoult's law. No azeotropic behavior was found in all systems at the measured temperatures. The experimental results were correlated with the Wilson model and compared to COSMO-SAC predictive model. Analyses of liquid and vapor phase

Erlin Sapei; Petri Uusi-Kyyny; Kari I. Keskinen; Juha-Pekka Pokki; Ville Alopaeus

2010-01-01

27

Vapor–liquid equilibria for 1,1,2,3,3,3-hexafluoropropyl, 2,2,2-trifluoroethyl ether with several organic solvents  

Microsoft Academic Search

The isobaric vapor–liquid equilibria (VLE) for the binary systems 1,1,2,3,3,3-hexafluoropropyl, 2,2,2-trifluoroethyl ether (HFE-449mec-f), i.e. CF3CHFCF2OCH2CF3, + methanol, ethanol, 2-propanol or trans-1,2-dichloroethylene have been measured at 101.3kPa. The measurements were made in an equilibrium still, developed in a previous study, with circulation of both the vapor and liquid phase. The four binary isobaric systems of the HFE-449mec-f with organic solvents exhibit

Toshihiko Hiaki; Makiko Nanao; Shingo Urata; Junji Murata

2002-01-01

28

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

ERIC Educational Resources Information Center

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…

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

2010-01-01

29

Semi-empirical correlation for binary interaction parameters of the Peng–Robinson equation of state with the van der Waals mixing rules for the prediction of high-pressure vapor–liquid equilibrium  

PubMed Central

Peng–Robinson equation of state is widely used with the classical van der Waals mixing rules to predict vapor liquid equilibria for systems containing hydrocarbons and related compounds. This model requires good values of the binary interaction parameter kij. In this work, we developed a semi-empirical correlation for kij partly based on the Huron–Vidal mixing rules. We obtained values for the adjustable parameters of the developed formula for over 60 binary systems and over 10 categories of components. The predictions of the new equation system were slightly better than the constant-kij model in most cases, except for 10 systems whose predictions were considerably improved with the new correlation.

Fateen, Seif-Eddeen K.; Khalil, Menna M.; Elnabawy, Ahmed O.

2012-01-01

30

Vapor-liquid phase separator permeability results  

NASA Technical Reports Server (NTRS)

Continued studies are described in the area of vapor-liquid phase separator work with emphasis on permeabilities of porous sintered plugs (stainless steel, nominal pore size 2 micrometer). The temperature dependence of the permeability has been evaluated in classical fluid using He-4 gas at atmospheric pressure and in He-2 on the basis of a modified, thermosmotic permeability of the normal fluid.

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

1981-01-01

31

Simplified thermodynamic functions for vapor-liquid phase separation and fountain effect pumps  

NASA Technical Reports Server (NTRS)

He-4 fluid handling devices near 2 K require novel components for non-Newtonian fluid transport in He II. Related sizing of devices has to be based on appropriate thermophysical property functions. The present paper presents simplified equilibrium state functions for porous media components which serve as vapor-liquid phase separators and fountain effect pumps.

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

1984-01-01

32

Group contribution method with SAFT EOS applied to vapor liquid equilibria of various hydrocarbon series  

Microsoft Academic Search

A new group contribution method is proposed using the statistical associating fluid theory (SAFT) equation of state (EOS), in order to describe the thermodynamic properties of hydrocarbon series. The method is developed for vapor–liquid equilibrium (VLE) calculations for a large number of hydrocarbons, with the use of several group parameters. SAFT models are chosen for the physical meaning of their

Sofiane Tamouza; J.-Philippe Passarello; Pascal Tobaly; J.-Charles de Hemptinne

2004-01-01

33

Vapor-liquid phase separator studies  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

34

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

SciTech Connect

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.

Lee, Changha; Holder, G.D. (Univ. of Pittsburgh, PA (United States))

1993-04-01

35

Vapor-Liquid Equilibria for Some Concentrated Aqueous PolymerSolutions  

SciTech Connect

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.

Striolo, Alberto; Prausnitz, John M.

1999-07-01

36

Calculation of Vapor-Liquid-Liquid Equilibria for the Fischer-Tropsch Reactor Effluents using Modified Peng-Robinson  

E-print Network

Calculation of Vapor-Liquid-Liquid Equilibria for the Fischer- Tropsch Reactor Effluents using A modified Peng­Robinson equation of state is used to develop the methods for calculating the thermodynamic in phase-equilibrium calculations. Different approaches have been presented in the literature to calculate

Skogestad, Sigurd

37

Vapor-liquid equilibria for the ternary system acetone + methanol + chlorobenzene at 101.325 kPa  

SciTech Connect

Distillation has been used as an effective method of separation in the chemical processing industry, and vapor liquid equilibrium (VLE) data are essential for development, design, and simulation of separation sequences of mixtures. Therefore, the purpose of the study of the thermodynamic equilibrium in the current mixture is the attractive possibility of the application of chlorobenzene as the solvent in the acetone + methanol extractive rectification, using a reverse volatility separation process. This paper reports vapor-liquid equilibrium results from the acetone + methanol + chlorobenzene mixture at a constant pressure of 101.325 kPa. The equilibrium data have been compared with those predicted by ASOG, UNIFAC, UNIFAC-Dortmund, UNIFAC-Lyngby group contributed methods, with lower standard deviations of the vapor molar fraction and temperature being calculated by the latter.

Orge, B.; Iglesias, M.; Dominguez, A.; Tojo, J. [Univ. de Vigo (Spain). Dept. de Ingenieria Quimica

1995-11-01

38

Vapor-liquid equilibrium of amine-water systems  

E-print Network

is defined by s E = log ( ? ) K s K Hyperconjugation effects due to J, hydrogens tend to decrease the rate constants for ester hydrolysis. The substitution of an alkyl group for a hydrogen increases the steric effect which decreases the rate con- stant... which decreases the hyperconjugation effect and thereby increases the rate constant. Hancock, Meyers, and Yager (47) have separated the steric and hyperconjugation effect and calculated corrected steric constants which are given by E = E + 0. 306 (N...

Chun, Kil Whan

2012-06-07

39

A theory of a curved vapor-liquid separation boundary: The lattice gas model  

NASA Astrophysics Data System (ADS)

Molecular theory of curved vapor-liquid interphase boundaries was considered in terms of the lattice gas model. The theory uses the quasi-thermodynamic concept of curved layers of a separation boundary with a large radius. The transition from a rectangular lattice to such layers is performed by the introduction of a variable number of the nearest neighbors. The problems (1) of the transition from distributed molecular models to layer models reflecting macroscopic symmetry of the interphase boundary and (2) of a minimum linear size of the surface region to which thermodynamic approaches are applicable were considered. Equations for the quasi-equilibrium distribution of molecules at the vapor-liquid boundary in a metastable system were constructed in the quasi-chemical approximation taking into account direct correlations between the nearest interacting molecules. A metastable state is maintained by a pressure jump described by the macro-scopic Laplace equation on a separation surface inside the interphase region. Equations for local mean pressure values and normal and tangential pressure tensor components inside the interphase region were constructed. These equations were used to obtain microscopic difference mechanical equilibrium equations for curved boundaries of spherical and cylindrical drops in the metastable state. The relation between the micro-scopic difference mechanical equilibrium equations and similar differential equations and the macroscopic Laplace equation, which described pressure jump in a metastable system, was considered. Various definitions of surface tension are discussed.

Tovbin, Yu. K.

2010-02-01

40

A field-space conformal-solution method: Binary vapor-liquid phase behavior  

NASA Astrophysics Data System (ADS)

The field-space conformal solution method provides an entirely new thermodynamic framework for the description of fluid mixtures in terms of the properties of a pure reference fluid. The utility and performance of the method are examined in the special case of vapor-liquid equilibrium correlation for simple mixtures. This is one of several cases in which field-space methods have numerical or theoretical advantages over methods presently used in mixture property correlation; only properties along the vapor pressure curve of the purefluid reference system are required for a complete description of the mixture phase behavior. Vapor-liquid equilibrium data for three binary hydrocarbon mixtures, n-butane + n-pentane, n-butane + n-hexane, and n-butane + n-octane, are correlated with a simple implementation of the method having two independent mixture parameters. Two pure-fluid equations of state, a Peng-Robinson equation and a 32-constant modified Benedict-Webb-Rubin equation, are tested as reference systems. The effects of differences in the quality of the reference system and of a range of mixture component size ratios are examined.

Storvick, T. S.; Fox, J. R.

1990-01-01

41

Combination downflow-upflow vapor-liquid separator  

DOEpatents

An improved vapor-liquid separator having a vertically disposed conduit for flow of a mixture. A first, second and third plurality of curved arms penetrate and extend within the conduit. A cylindrical member is radially spaced from the conduit forming an annulus therewith and having perforations and a retaining lip at its upper end.

Kidwell, John H. (Uniontown, OH); Prueter, William P. (Alliance, OH); Eaton, Andrew M. (Alliance, OH)

1987-03-10

42

A Vapor-Liquid Equilibria Model for Hydrofluorocarbons and Their Binary Mixtures  

NASA Astrophysics Data System (ADS)

A novel thermodynamic model has been proposed so as to calculate the thermodynamic properties at the vapor-liquid coexistence of HFC (hydrofluorocarbon) refrigerants and their binary mixtures. This model has been developed by modifying the Patel-Teja equation, well-known cubic equation of state, for HFC refrigerants, R- 32, R-125, R-134a, and their binary mixtures for temperatures from 220 K to their critical temperatures. The developed model has features in calculating various thermodynamic properties with ease but accurately. The calculated results on the vapor-liquid equilibrium (VLE) properties by the present model illustrate its superiority to the conventional cubic equations of state. A comparison of the proposed model with the so-called modified Benedict-Webb-Rubin (MBWR) model and the multi-term Helmholtz function model confirms equivalent effectiveness and accuracy by the present model and, therefore, it would be concluded that the proposed model is very powerful in various practical application in refrigeration industry.

Li, Jin; Sato, Haruki; Yokozeki, Akimichi; Watanabe, Koichi

43

Silicon MEMS vaporizing liquid microthruster with internal microheater  

Microsoft Academic Search

This paper reports a silicon MEMS vaporizing liquid microthruster (VLM) with an internal p-diffused microheater. The device fabrication and testing have been briefly described. The VLM consisting of two micromachined, bonded silicon chips produces thrusts in the range of 5 µN to 120 µN with a heater power of 1 W to 2.4 W at a water flow rate of

D K Maurya; S Das; S K Lahiri

2005-01-01

44

Vapor-liquid Coexistence Curves for Methanol and Methane using Dispersion-Corrected Density Functional Theory  

SciTech Connect

First principles Monte Carlo simulations in the Gibbs and isobaric-isothermal ensembles were performed to map the vapor-liquid coexistence curves (VLCC) of methanol and methane described by Kohn-Sham density functional theory using the Becke-Lee-Yang-Parr (BLYP) exchange and correlation functionals with the Grimme correction term for dispersive (D2) interactions. The simulations indicate that the BLYP-D2 description underpredicts the saturated vapor densities and overpredicts the saturated liquid densities and critical and boiling temperatures for both compounds. Although the deviations are quite large, these results present a significant improvement over the BLYP functional without the correction term which misses the experimental results by a larger extent in the opposite direction. With the D2 correction, an increase in the basis set does not lead to significant changes in the VLCC properties. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

McGrath, Matthew J.; Kuo, I-F W.; Ghogomu, Julius N.; Mundy, Christopher J.; Siepmann, Joern I.

2011-10-13

45

Toward a Monte Carlo program for simulating vapor-liquid phase equilibria from first principles  

SciTech Connect

Efficient Monte Carlo algorithms are combined with the Quickstep energy routines of CP2K to develop a program that allows for Monte Carlo simulations in the canonical, isobaric-isothermal, and Gibbs ensembles using a first principles description of the physical system. Configurational-bias Monte Carlo techniques and pre-biasing using an inexpensive approximate potential are employed to increase the sampling efficiency and to reduce the frequency of expensive ab initio energy evaluations. The new Monte Carlo program has been validated through extensive comparison with molecular dynamics simulations using the programs CPMD and CP2K. Preliminary results for the vapor-liquid coexistence properties (T = 473 K) of water using the Becke-Lee-Yang-Parr exchange and correlation energy functionals, a triple-zeta valence basis set augmented with two sets of d-type or p-type polarization functions, and Goedecker-Teter-Hutter pseudopotentials are presented. The preliminary results indicate that this description of water leads to an underestimation of the saturated liquid density and heat of vaporization and, correspondingly, an overestimation of the saturated vapor pressure.

McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; Vandevondele, J; Sprik, M; Hutter, J; Mohamed, F; Krack, M; Parrinello, M

2004-10-20

46

Vapor–liquid equilibria for binary mixtures of carbon dioxide with 1,2-dimethoxybenzene, 2-methoxyphenol, or p-cresol at elevated pressures  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) phase compositions were measured for three binary systems of carbon dioxide with 1,2-dimethoxybenzene, 2-methoxyphenol, or p-cresol at temperatures from 323.15 to 423.15 K and pressures up to 20 MPa. The solubilities of these close-boiling heavy components in the vapor phase were compared over the experimental conditions. Henry's constants were calculated from the isothermal equilibrium data. The temperature

Ming-Jer Lee; Chi-Fu Kou; Jung-Wen Cheng; Ho-mu Lin

1999-01-01

47

Vapor–liquid equilibria of novel chemicals and their mixtures as R-22 alternatives  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) vapor pressures are reported for binary mixtures; octafluoromethylethylether+1,1-difluoroethane (RE218\\/R152a), trifluoromethylpentafluorosulfur(VI)+1,1-difluoroethane (CF3SF5\\/R152a), hexafluorodimethylthioether+1,1,1,2-tetrafluoroethane (CF3SCF3\\/R134a), and pentafluorodimethylether+1,1,1-trifluorodimethylether (RE125\\/RE143a). The mixtures; (RE218\\/R152a), (CF3SF5\\/R152a), and (CF3SCF3\\/R134a) form minimum boiling azeotropes with the normal boiling points; 237.9K (?35.3°C), 239.7K (?33.5°C), and 243.0K (?30.2°C), respectively, and gas–liquid critical temperatures of 353.3K (80.1°C), 365.7K (92.5°C) and 368.2K (95.0°C), respectively. The azeotropic mixtures have sufficiently

Ismail Kul; Darryl D DesMarteau; Adolph L Beyerlein

2000-01-01

48

Vapors-liquid phase separator. [infrared telescope heat sink  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

49

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

50

Effect of dimensionality on vapor-liquid phase transition  

SciTech Connect

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.

Singh, Sudhir Kumar, E-mail: sksingh@thapar.edu [Department Chemical Engineering, Thapar University, Patiala-147004 Punjab (India)

2014-04-24

51

Effect of dimensionality on vapor-liquid phase transition  

NASA Astrophysics Data System (ADS)

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.

Singh, Sudhir Kumar

2014-04-01

52

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

PubMed

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

Rajesh, John Anthuvan; Pandurangan, Arumugam

2014-04-01

53

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

USGS Publications Warehouse

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.

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

1978-01-01

54

Riemannian geometry study of vapor-liquid phase equilibria and supercritical behavior of the Lennard-Jones fluid.  

PubMed

The behavior of thermodynamic response functions and the thermodynamic scalar curvature in the supercritical region have been studied for a Lennard-Jones fluid based on a revised modified Benedict-Webb-Rubin equation of state. Response function extrema are sometimes used to estimate the Widom line, which is characterized by the maxima of the correlation lengths. We calculated the Widom line for the Lennard-Jones fluid without using any response function extrema. Since the volume of the correlation length is proportional to the Riemannian thermodynamic scalar curvature, the locus of the Widom line follows the slope of maximum curvature. We show that the slope of the Widom line follows the slope of the isobaric heat capacity maximum only in the close vicinity of the critical point and that, therefore, the use of response function extrema in this context is problematic. Furthermore, we constructed the vapor-liquid coexistence line for the Lennard-Jones fluid using the fact that the correlation length, and therefore the thermodynamic scalar curvature, must be equal in the two coexisting phases. We compared the resulting phase envelope with those from simulation data where multiple histogram reweighting was used and found striking agreement between the two methods. PMID:22587083

May, Helge-Otmar; Mausbach, Peter

2012-03-01

55

A model of vapor-liquid equilibria for acid gas-alkanolamine-water systems  

SciTech Connect

A physico-chemical model was developed for representing liquid phase chemical equilibria and vapor-liquid (phase) equilibria of H{sub 2}SCO{sub 2}-alkanolamine-water systems. The equilibrium composition of the liquid phase is determined by minimization of the Gibbs free energy. Activity coefficients are represented with the Electrolyte-NRTL equation treating both long-range electrostatic interactions and short-range binary interactions between liquid phase species. Vapor phase fugacity coefficients are calculated using the Redlich-Kwong-Soave Equation of State. Adjustable parameters of the model, binary interaction parameters and carbamate stability constants, were fitted on published binary system alkanolamine-water and ternary system (H{sub 2}S-alkanolamine-water, CO{sub 2}-alkanolamine-water) VLE data. The Data Regression System of ASPEN PLUS, based upon the Maximum Likelihood Principle, was used to estimate adjustable parameters. Ternary system measurements used in parameter estimation ranged in temperature from 25 to 120{degree}C in alkanolamine concentration from 1 to 5 M, in acid gas loading from 0 to 1.5 moles per mole alkanolamine, and in acid gas partial pressure from 0.1 to 1,000 kPa. Maximum likelihood estimates of ternary system H{sub 2} or CO{sub 2} equilibrium partial pressures and liquid phase concentrations were found to be in good agreement with measurements for aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), diglycolamine (DGA), and methyldiethanolamine (MDEA) indicating that the model successfully represents ternary system data. The model was extended to represent CO{sub 2} solubility in aqueous mixtures of MDEA with MEA or DEA. The solubility was measured at 40 and 80{degree}C over a wide range of CO{sub 2} partial pressures. These measurements were used to estimate additional binary parameters of the mixed solvent systems.

Austgen, D.M. Jr.

1989-01-01

56

Design, fabrication and performance evaluation of a vaporizing liquid microthruster  

NASA Astrophysics Data System (ADS)

A recent application domain of MEMS technology is in the development of microthrusters for micro-/nanosatellites. Among the various types of MEMS microthruster developed so far, the vaporizing liquid microthruster (VLM) has been widely explored for its capability to produce continuously variable thrust in the micro-Newton (µN) to mili-Newton (mN) range. This paper reports the design and experimental validation of silicon MEMS VLM consisting of a microcavity, inlet channel and converging-diverging (C-D) in-plane exit nozzle integrated in two micromachined bonded chips and sandwiched between two p-diffused microheaters, located at the top and bottom surface of the device. Structural configuration was designed using simple analytical equations to achieve maximum thrust force by controlling the inlet propellant flow and heater power of VLM in an efficient way. In addition, a 3D model using a computational fluid dynamics technique was constructed to simulate the aft section of VLM for the investigation of its aerodynamic behavior. The device fabrication and testing have been briefly described. The fabricated VLM is capable to produce 1 mN thrust using maximum heater power of 3.6 W at a water flow rate of 2.04 mg s-1 using an in-plane C-D exit nozzle of throat area 130 µm × 100 µm. A detailed thrust force measurement was carried out with the variation of input heater power for different mass flow conditions and exit to throat area ratio of the exit nozzle, and the results were interpreted with the theoretical model. The model gives considerable physical insight in the operation of the VLM. Finally, a performance comparison with other published VLM results indicates that the present design can yield comparatively more thrust force with much less input power. A performance comparison with other published VLM results indicates that the present design can achieve improved performance by integrating two heaters with appropriate chamber volume in respect of propellant flow rate and input power for obtaining a supersaturated dry stream.

Kundu, Pijus; Kanti Bhattacharyya, Tarun; Das, Soumen

2012-02-01

57

Vapor–liquid equilibria for binary and ternary mixtures of ethanol, 2-butanone, and 2,2,4-trimethylpentane at 101.3 kPa  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) at 101.3kPa have been determined for the ternary system ethanol+2-butanone+2,2,4-trimethylpentane (isooctane) and its constituent binary systems: ethanol+2,2,4-trimethylpentane, ethanol+2-butanone, and 2-butanone+2,2,4-trimethylpentane. Minimum boiling azeotropes were observed for all these binary systems. No azeotropic behavior was found for the ternary system. Thermodynamic consistency tests were performed for all VLE data. The activity coefficients of the binary mixtures were satisfactorily

Chao-Cheng Wen; Chein-Hsiun Tu

2007-01-01

58

Isobaric groundwater well  

DOEpatents

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.

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

1999-01-01

59

Vapor-liquid equilibria of binary mixtures containing methane, ethane, and carbon dioxide from molecular simulation  

NASA Astrophysics Data System (ADS)

The NpT + test particle method is used in order to predict vapor-liquid equilibria of the mixtures methane + ethane, methane + carbon dioxide, and carbon dioxide +ethane by molecular simulations. The pure-component molecular models were fitted to the experimental vapor pressures and saturated liquid densities in previous papers, which used the same simulation method for the determination of the phase equilibria. For each binary mixture the two unlike interaction parameters were determined from one experimental excess volume and one excess enthalpy. Based on these molecular models the vapor-liquid phase equilibria were calculated for each mixture at three temperatures. Comparison of the pressure-composition data with experimental results shows the high predictive power of this molecular based procedure. This statement is confirmed by additional comparisons of the pressure-composition diagrams and the pressure-density diagrams with results from equations of state.

Vrabec, J.; Fischer, J.

1996-07-01

60

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

61

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

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

62

Sintered plug flow modulation of a vapor-liquid phase separator for a helium II vessel  

NASA Technical Reports Server (NTRS)

Presented is a system for modulation of a superfluid (helium II) flow in a vapor-liquid phase separator, for use in cryogenic storage tanks in future space missions. The system consists of a semicircular mechanically operated shutter, downstream of the separator plug, rotated at 0.1 rpm to control the operational surface area of the separator. The mass flow rate was varied from 10 to 22 mg/s. Pressure gradients across the plug are also discussed.

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

1984-01-01

63

An analytical model of a silicon MEMS vaporizing liquid microthruster and some experimental studies  

Microsoft Academic Search

A recent application of the MEMS technology is in the field of microthrusters for micro\\/nano satellites. A silicon MEMS vaporizing liquid microthruster (VLM) produces continuously variable thrust in the range from ?N to mN. The theoretical simulation of a VLM involves complex numerical 3D micro-fluidic, thermodynamic and electro-thermal solutions. A fast analytical method is, however, desirable in the initial phase

D. K. Maurya; S. Das; S. K. Lahiri

2005-01-01

64

Growth characteristics of silicon nanowires synthesized by vapor–liquid–solid growth in nanoporous alumina templates  

Microsoft Academic Search

The fabrication of Si nanowires has been demonstrated using a combination of template-directed synthesis and vapor–liquid–solid (VLS) growth. The use of nanoporous alumina membranes for VLS growth provides control over nanowire diameter while also enabling the production of single crystal material. An investigation of the growth characteristics of Si nanowires over a temperature range from 400°C to 600°C, and over

Kok-Keong Lew; Joan M Redwing

2003-01-01

65

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

SciTech Connect

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.

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

2008-02-05

66

Vapor–liquid equilibria and thermophysical behavior of the SPC-HW model for heavy water  

Microsoft Academic Search

The vapor–liquid coexistence curve of the simple point charge heavy-water model (SPC-HW), [J. Chem. Phys., 114, 8064–8067 (2001)] is determined by Gibbs Ensemble Monte-Carlo (GEMC) simulation. The estimated critical conditions of the model based on the Wegner-type expansion for the order parameters and the rectilinear diameter are ?c = 0.300 g\\/cc, Tc = 661 K and Pc = 156 bars. The dielectric constant determined by isothermal–isochoric molecular dynamics is

A. A. ChIalvo; J. Horita

2005-01-01

67

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

68

Water-mediated ion–ion interactions are enhanced at the water vapor–liquid interface  

PubMed Central

There is overwhelming evidence that ions are present near the vapor–liquid interface of aqueous salt solutions. Charged groups can also be driven to interfaces by attaching them to hydrophobic moieties. Despite their importance in many self-assembly phenomena, how ion–ion interactions are affected by interfaces is not understood. We use molecular simulations to show that the effective forces between small ions change character dramatically near the water vapor–liquid interface. Specifically, the water-mediated attraction between oppositely charged ions is enhanced relative to that in bulk water. Further, the repulsion between like-charged ions is weaker than that expected from a continuum dielectric description and can even become attractive as the ions are drawn to the vapor side. We show that thermodynamics of ion association are governed by a delicate balance of ion hydration, interfacial tension, and restriction of capillary fluctuations at the interface, leading to nonintuitive phenomena, such as water-mediated like charge attraction. “Sticky” electrostatic interactions may have important consequences on biomolecular structure, assembly, and aggregation at soft liquid interfaces. We demonstrate this by studying an interfacially active model peptide that changes its structure from ?-helical to a hairpin-turn–like one in response to charging of its ends. PMID:24889634

Venkateshwaran, Vasudevan; Vembanur, Srivathsan; Garde, Shekhar

2014-01-01

69

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

SciTech Connect

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.

Kundu, M.; Sen, A.; Ganesh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India); Avinash, K. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2014-10-15

70

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

SciTech Connect

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.

Zervos, M., E-mail: zervos@ucy.ac.cy; Giapintzakis, J. [Nanotechnology Research Centre (NRC), University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Mihailescu, C. N. [Nanotechnology Research Centre (NRC), University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); National Institute for Laser, Plasma and Radiation Physics, Str. Atomistilor, P.O. Box MG-36, 077125 Magurele (Romania); Luculescu, C. R. [Department of Mechanical and Manufacturing Engineering, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); National Institute for Laser, Plasma and Radiation Physics, Str. Atomistilor, P.O. Box MG-36, 077125 Magurele (Romania); Florini, N.; Komninou, Ph.; Kioseoglou, J. [Nanostructured Materials Microscopy Group (NMMG), Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Othonos, A. [Nanotechnology Research Centre (NRC), University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus); Research Center of Ultrafast Science, Department of Physics, University of Cyprus, P.O. Box 20537, Nicosia 1678 (Cyprus)

2014-05-01

71

Vapor-liquid-solid growth of silicon nanowires by chemical vapor deposition on implanted templates  

NASA Astrophysics Data System (ADS)

We show the realization of a distinctive nanoscale metal template for the vapor-liquid-solid growth of semiconductor nanowires. The template is based on the high-dose implantation of metal ions into silicon substrates and subsequent annealing upon which the atoms agglomerate. In case the wafer is amorphized at the surface upon implantation and the metal atoms reside within the amorphized part of the wafer, a high diffusion coefficient (holds for Au) of the metal atoms in amorphous silicon (compared to crystalline silicon) yields agglomeration of metal atoms at the wafer surface and the formation of supercritical metal nanoparticles. We show the implantation of gold (dose at least 1×1016cm-2) and discuss the option to use this type of template formation with other metals, such as gallium, indium, aluminum, and palladium, which are partly easy to be oxidized.

Christiansen, S.; Schneider, R.; Scholz, R.; Gösele, U.; Stelzner, Th.; Andrä, G.; Wendler, E.; Wesch, W.

2006-10-01

72

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

73

Formation of Fluctuations in the Molecular Slab via Isobaric Thermal Instability  

E-print Network

The frictional heating by ion-neutral drift is calculated and its effect on isobaric thermal instability is carried out. Ambipolar drift heating of one-dimensional self-gravitating magnetized molecular slab is used under the assumptions of quasi-magnetohydrostatic and local ionization equilibrium. We see that ambipolar drift heating is inversely proportional to density and its value in some regions of the slab can be significantly larger than the average heating rates of cosmic rays and turbulent motions. The results show that the isobaric thermal instability can occur in some regions of the slab; therefore it may produce the slab fragmentation and formation of the AU-scale condensations.

M. Nejad-Asghar

2007-05-02

74

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

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

75

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

NASA Astrophysics Data System (ADS)

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.

How Cheah, Kean; Low, Kay-Soon

2015-01-01

76

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

E-print Network

A systematic investigation on vapor-liquid equilibria (VLE) of dipolar and quadrupolar fluids is carried out by molecular simulation to develop a new Helmholtz energy contribution for equations of state (EOS). Twelve two-center Lennard-Jones plus point dipole and point quadrupole model fluids (2CLJDQ) are studied for different reduced dipolar moments mu^{*2}=6,12, reduced quadrupolar moments Q^{*2}=2,4 and reduced elongations L^*=0, 0.505,1. Temperatures cover a wide range from about 55% to about 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 non-spherical molecules is developed. The expression is based on a third-order perturbation theory and the model constants are adjusted to the present 2CLJDQ simulation resu...

Vrabec, Jadran

2009-01-01

77

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

78

Identification of an intrinsic source of doping inhomogeneity in vapor-liquid-solid-grown nanowires.  

PubMed

The vapor-liquid-solid (VLS) process of semiconductor nanowire growth is an attractive approach to low-dimensional materials and heterostructures because it provides a mechanism to modulate, in situ, nanowire composition and doping, but the ultimate limits on doping control are ultimately dictated by the growth process itself. Under widely used conditions for the chemical vapor deposition growth of Si and Ge nanowires from a Au catalyst droplet, we find that dopants incorporated from the liquid are not uniformly distributed. Specifically, atom probe tomographic analysis revealed up to 100-fold enhancements in dopant concentration near the VLS trijunction in both B-doped Si and P-doped Ge nanowires. We hypothesize that radial and azimuthal inhomogeneities arise from a faceted liquid-solid interface present during nanowire growth, and we present a simple model to account for the distribution. As the same segregation behavior was observed in two distinct semiconductors with different dopants, the observed inhomogeneity is likely to be present in other VLS grown nanowires. PMID:23237496

Connell, Justin G; Yoon, KunHo; Perea, Daniel E; Schwalbach, Edwin J; Voorhees, Peter W; Lauhon, Lincoln J

2013-01-01

79

Molecular Simulation Study of the Vapor–Liquid Interfacial Behavior of a Dimer-forming Associating Fluid  

Microsoft Academic Search

Grand-canonical transition-matrix Monte Carlo simulation is applied to analyze the effect of molecular association on the vapor–liquid coexistence and interfacial behavior of square-well based dimerizing fluids. Finite-size scaling techniques are implemented in conjunction with histogram reweighting to determine the infinite-system surface tension from a series of finite-size simulations. The effect of strength of association and size of association site on

Jayant K. Singh; David A. Kofke

2004-01-01

80

Whisker reinforced structural ceramics: Progress in the VLS growth and use of long silicon carbide whiskers. [Vapor-liquid-solid  

SciTech Connect

A VLS (vapor-liquid-solid) whisker growth process, optimized for the production of short (approx.10 mm lengths) SiC whiskers, was modified to produce greater than or equal to 25 mm long whiskers. In conjunction with this modification, a plan was developed for incorporating an artificial-intelligence system to enhance the whisker growth process. An oriented whisker ribbon was produced from the long whiskers, as a step toward the development of a staple whisker yarn.

Gac, F.D.; Shalek, P.D.; Parkinson, W.J.; Edwards, C.; Price, J.B.

1987-01-01

81

Vapor-liquid equilibria for copolymer+solvent systems: Effect of intramolecular repulsion  

SciTech Connect

Role of intramolecular interactions in blend miscibility is well documented for polymer+copolymer mixtures. Some copolymer+polymer mixtures are miscible although their corresponding homopolymers are not miscible; for example, over a range of acrylonitrile content, styrene/acrylonitrile copolymers are miscible with poly(methyl methacrylate) but neither polystyrene nor polyacrylonitrile is miscible with poly(methyl methacrylate). Similarly, over a composition range, butadiene/acrylonitrile copolymers are miscible with poly(vinyl chloride) while none of the binary combinations of the homopolymers [polybutadiene, polyacrylonitrile, and poly(vinyl chloride)] are miscible. This behavior has been attributed to ``intramolecular repulsion`` between unlike copolymer segments. We have observed similar behavior in vapor-liquid equilibria (VLE) of copolymer+solvent systems. We find that acrylonitrile/butadiene copolymers have higher affinity for acetonitrile solvent than do polyacrylonitrile or polybutadiene. We attribute this non-intuitive behavior to ``intramolecular repulsion`` between unlike segments of the copolymer. This repulsive interaction is weakened when acetonitrile molecules are in the vicinity of unlike copolymer segments, favoring copolymer+solvent miscibility. We find similar behavior when acetonitrile is replaced by methyl ethyl ketone. To best knowledge, this effect has not been reported previously for VLE. We have obtained VLE data for mixtures containing a solvent and a copolymer as a function of copolymer composition. It appears that, at a given solvent partial pressure, there may be copolymer composition that yields maximum absorption of the solvent. This highly non-ideal VLE phase behavior may be useful for optimum design of a membrane for a separation process.

Gupta, R.B.; Prausnitz, J.M.

1995-03-01

82

Correlation of Zeno (Z = 1) line for supercritical fluids with vapor-liquid rectilinear diameters  

SciTech Connect

For a wide range of substances, extending well beyond the regime of corresponding states behavior, the contour in the temperature-density plane along which the compressibility factor Z = P/{rho}kT is the same as for an ideal gas is nearly linear. This Z = 1 contour, termed the Zeno line, begins deep in the liquid region and ascends as the density decreases to the Boyle point of the supercritical fluid, specified by the temperature T{sub B} for which (dZ/d{rho}){sub T} = 0 as {rho} {r_arrow} 0; equivalent, at T{sub B} the second virial coefficient vanishes. The slope of the Z = 1 line is {minus}B{sub 3}/(dB{sub 2}/dT), in terms of the third virial coefficient and the derivative of the second, evaluated at T{sub B}. Previous work has examined the Zeno line as a means to extend corresponding states and to enhance other practical approximations. Here the authors call attention to another striking aspect, a strong correlation with the line of rectilinear diameters defined by the average of the subcritical vapor and liquid densities. This correlation is obeyed well by empirical data for many substances and computer simulations for a Lennard-jones potential; the ratios of the intercepts and slopes for the Zeno and rectilinear diameter liens are remarkably close to those predicted by the van der Waals equation, 8/9 and 16/9, respectively. Properties of the slightly imperfect fluid far above the critical point thus implicitly determine the diameter of the vapor-liquid coexistence curve below the critical point.

Ben-Amotz, D.; Herschbach, D.R. [Exxon Research and Engineering Co., Annandale, NJ (United States). Corporate Research Science Lab.

1996-08-01

83

Phase equilibrium studies  

SciTech Connect

A phase equilibrium model has been developed for the SRC-I process, as well as the other coal liquefaction processes. It is applicable to both vapor/liquid and liquid/liquid equilibria; it also provides an approximate but adequate description of aqueous mixtures where the volatile electrolyte components dissociate to form ionic species. This report completes the description of the model presented in an earlier report (Mathias and Stein, 1983a). Comparisons of the model to previously published data on coal-fluid mixtures are presented. Further, a preliminary analysis of new data on SRC-I coal fluids is presented. Finally, the current capabilities and deficiencies of the model are discussed. 25 references, 17 figures, 30 tables.

Mathias, P.M.; Stein, F.P.

1983-09-01

84

Synthesis and characterization of group IV semiconductor nanowires by vapor-liquid-solid growth  

NASA Astrophysics Data System (ADS)

There is currently intense interest in one-dimensional nanostructures, such as nanotubes and nanowires, due to their potential to test fundamental concepts of dimensionality and to serve as building blocks for nanoscale devices. Vapor-liquid-solid (VLS) growth, which is one of the most common fabrication methods, has been used to produce single crystal semiconductor nanowires such as silicon (Si), germanium (Ge), and gallium arsenide (GaAs). In the VLS growth of Group IV semiconductor nanowires, a metal, such as gold (Au) is used as a catalyst agent to nucleate whisker growth from a Si-containing (silane (SIH4)) or Ge-containing vapor (germane (GeH 4)). Au and Si/Ge form a liquid alloy that has a eutectic temperature of around 360°C, which, upon supersaturation, nucleates the growth of a Si or Ge wire. The goal of this work is to develop a more fundamental understanding of VLS growth kinetics and intentional doping of Group IV semiconductor nanowires in order to better control the properties of the nanowires. The fabrication of p-type and n-type Si nanowires will be studied via the addition of dopant gases such as diborane (B2H 6), trimethylboron (TMB), and phosphine (PH3) during growth. The use of gaseous dopant sources provides more flexibility in growth, particularly for the fabrication of p-n junctions and structures with axial dopant variations (e.g. p+-p- p+). The study is then extended to fabricate SiGe alloy nanowires by mixing SiH4 and GeH4. Bandgap engineering in Si/SiGe heterostructures can lead to novel devices with improved performance compared to those made entirely of Si. The scientific findings will lead to a better understanding of the fabrication of Si/SiGe axial and radial heterostructure nanowires for functional nanowire device structures, such as heterojunction bipolar transistors (HBTs) and high electron mobility transistors (HEMTs). Eventually, the central theme of this research is to provide a scientific knowledge base and foundation for the design of Si, Ge, and SiGe nanostructures that will be of importance in nanoscale device applications.

Lew, Kok-Keong

85

Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation  

Microsoft Academic Search

Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random

Ram B. Gupta; John M. Prausnitz

1995-01-01

86

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

USGS Publications Warehouse

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.

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

2008-01-01

87

Sea-Level Pressure: Contouring Isobars  

NSDL National Science Digital Library

This interactive feature shows how an isobar (atmospheric pressure) map is drawn. Students can select an individual contour value and watch as the animation correctly places the line with respect to pressure values on the map. The animation also marks high and low pressure systems, toggles between coded (station model) and decoded pressure values, and permits the user to color the spaces between the contour lines on the map.

88

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

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. ?? 1986.

Bischoff, J.L.; Rosenbauer, R.J.; Pitzer, K.S.

1986-01-01

89

Early appearance of ? isobars in neutron stars  

NASA Astrophysics Data System (ADS)

We discuss the formation of ? isobars in neutron star matter. We show that their threshold density strictly correlates with the density derivative of the symmetry energy of nuclear matter: the L parameter. By restricting L to the range of values indicated by recent experimental and theoretical analysis, i.e., 40 MeV?L ?62 MeV , we find that ? isobars appear at a density of the order of 2 to 3 times the nuclear matter saturation density, i.e., the same range as for the appearance of hyperons. The range of values of the couplings of the ? s with the mesons is restricted by the analysis of the data obtained from photoabsorption, electron and pion scattering on nuclei. If the potential of the ? in nuclear matter is close to the one indicated by the experimental data then the equation of state becomes soft enough that a "? puzzle" exists, similar to the "hyperon puzzle" widely discussed in the literature. Possible solutions to this puzzle are also discussed.

Drago, Alessandro; Lavagno, Andrea; Pagliara, Giuseppe; Pigato, Daniele

2014-12-01

90

Constructing a superhydrophobic surface on polydimethylsiloxane via spin coating and vapor-liquid sol-gel process.  

PubMed

In this study, a superhydrophobic surface on polydimethylsiloxane (PDMS) substrate was constructed via the proposed vapor-liquid sol-gel process in conjunction with spin coating of dodecyltrichlorosilane (DTS). Unlike the conventional sol-gel process where the reaction takes place in the liquid phase, layers of silica (SiO(2)) particles were formed through the reaction between the reactant spin-coated on the PDMS surface and vapor of the acid solution. This led to the SiO(2) particles inlaid on the PDMS surface. Followed by subsequent spin coating of DTS solution, the wrinkle-like structure was formed, and the static contact angle of the water droplet on the surface could reach 162 degrees with 2 degrees sliding angle and less than 5 degrees contact angle hysteresis. The effect of layers of SiO(2) particles, concentrations of DTS solution and surface topography on superhydrophobicity of the surface is discussed. PMID:20020726

Peng, Yu-Ting; Lo, Kuo-Feng; Juang, Yi-Je

2010-04-01

91

Fabrication of GaN nanowires by a vapor–liquid–solid method using metal–organic chemical vapor deposition  

NASA Astrophysics Data System (ADS)

We examined the characteristics of one-dimensional GaN nanowires grown by a vapor–liquid–solid method using metal organic chemical vapor deposition equipment. GaN nanowires grown at 700 °C were uniform in size, approximately 5 µm in length and 200 nm in diameter, with a high density. X-ray diffraction showed that the nanowires grew as wurtzite GaN with random directions. Photoluminescence at 4 K revealed excitonic emission but no yellow luminescence. By using a temperature dependant photoluminescence, the bandgaps at 0 K of free exiton (FX) and donor-bound exciton (D°X) calculated using Varshni’s equation were 3.476 and 3.470 eV, respectively. The activation energies of D°X and FX were 19.1 and 12.8 meV, respectively.

Yang, Jae-Yeol; Yoon, Jae-Sik; O, Byung-Sung; Kim, Chang-Su; Hong, Soon-Jik; Hong, Hyun-Seon; Kim, Jae-Kwan; Lee, Ji-Myon

2015-02-01

92

Theoretical study of vapor-liquid homogeneous nucleation using stability analysis of a macroscopic phase.  

PubMed

Stability analysis is generally used to verify that the solution to phase equilibrium calculations corresponds to a stable state (minimum of the free energy). In this work, tangent plane distance analysis for stability of macroscopic mixtures is also used for analyzing the nucleation process, reconciling thus this analysis with classical nucleation theories. In the context of the revised nucleation theory, the driving force and the nucleation work are expressed as a function of the Lagrange multiplier corresponding to the mole fraction constraint from the minimization problem of stability analysis. Using a van der Waals fluid applied to a ternary mixture, Lagrange multiplier properties are illustrated. In particular, it is shown how the Lagrange multiplier value is equal to one on the binodal and spinodal curves at the same time as the driving force of nucleation vanishes on these curves. Finally, it is shown that, on the spinodal curve, the nucleation work from the revised and generalized nucleation theories are characterized by two different local minima from stability analysis, irrespective of any interfacial tension models. PMID:23061836

Carreón-Calderón, Bernardo

2012-10-14

93

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

PubMed

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. PMID:24842296

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

2014-06-21

94

Ab initio potential energy surface for methane and carbon dioxide and application to vapor-liquid coexistence.  

PubMed

A six-dimensional intermolecular potential energy surface for a rigid methane (CH4) and carbon dioxide (CO2) dimer was developed from the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory. A total of 466 grid points distributed to 46 orientations were calculated from the complete basis set limit extrapolation based on up to aug-cc-pVQZ basis set. A modified site-site pair potential function was proposed for rapid representation of the high level ab initio calculations. A nonadditive three-body interaction was represented by the Axilrod-Teller-Muto expression for mixtures with the polarizability and the London dispersion constant of each molecule. Second to fourth virial coefficients of CH4 and CO2 mixtures were calculated using both the Mayer sampling Monte Carlo method and the present potential functions. The virial equation of state derived from these coefficients was used to predict the pVT values and showed good agreement with experimental data below 200 bar at 300 K. The vapor-liquid coexistence curves of pure CH4, CO2 and their mixtures were presented with the aid of Gibbs ensemble Monte Carlo simulations. The predicted tie lines agreed with the experimental data within the uncertainties up to near the critical point. PMID:25134567

Pai, Sung Jin; Bae, Young Chan

2014-08-14

95

Essential role of catalysts (Mn, Au, and Sn) in the vapor liquid solid growth kinematics of ZnS nanowires  

SciTech Connect

In this paper, we demonstrate that surface energy of the catalyst is a vital parameter for the growth rate, self doping of the self assembled nanowires synthesized by employing vapor liquid solid growth technique. The synthesis of ZnS nanowires was done by selectively using three different catalysts (Mn, Au, and Sn), where Au, is the most common catalyst, was used as a reference. The distinctive difference in the growth rate was due to the surface energy of the metal alloy droplet and the interface energies, as explained theoretically using thermodynamic approach. We have found that the activation energy of diffusion of (Zn, S) species in the catalyst droplet was low in Sn (0.41?eV for Zn and 0.13?eV for S) and high in Mn (1.79?eV for Zn and 0.61?eV for S) compared to Au (0.62?eV for Zn and 0.21?eV for S) catalyzed ZnS nanostructures. The thermodynamic calculations predicted the growth rates of Sn (7.5?nm/s) catalyzed nanowires was faster than Au (5.1?nm/s) and Mn (4.6?nm/s) catalyzed ZnS nanostructures, which were in agreement with the experimental results. Finally, the location of the catalyst as dopant in the grown nanostructure was predicted and compared with experimental observations.

Rehman, S.; Shehzad, M. A.; Hafeez, M.; Bhatti, A. S., E-mail: asbhatti@comsats.edu.pk [Center for Micro and Nano Devices (CMND), Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

2014-01-14

96

Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation  

SciTech Connect

Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random copolymers. Some homopolymers were also studied: polyacrylonitrile, polybutadiene, poly(butyl methacrylate), poly(ethylene oxide), polystyrene, and poly(vinyl acetate). The composition of the copolymer may have a surprising effect on VLE. Normally, deviation from ideal behavior lies between those of the constituent homopolymers, according to the copolymer composition, as observed for cyclohexane + poly(ethylene-co-vinyl acetate) and chloroform + poly(styrene-co-butyl methacrylate). However, the strong nonideal behavior observed for systems containing hydrocarbons and poly(butadiene-co-acrylonitrile) shows that the effect of acrylonitrile is in excess of that expected form the copolymer composition. The perturbed hard-sphere chain (PHSC) equation of state was used to represent VLE of the copolymer solutions studied here.

Gupta, R.B.; Prausnitz, J.M. [Lawrence Berkeley Lab., CA (United States)

1995-07-01

97

Interpreting Kelvin probe force microscopy under an applied electric field: local electronic behavior of vapor-liquid-solid Si nanowires.  

PubMed

Kelvin probe force microscopy (KPFM) is used to characterize the electrical characteristics of vapor-liquid-solid (VLS) Si nanowires (NWs) that are grown in-place between two predefined electrodes. KPFM measurements are performed under an applied bias. Besides contact potential differences due to differing materials, the two other primary contributions to measured variations on Si NWs between electrodes are: trapped charges at interfaces, and the parallel and serial capacitance, which are accounted for with voltage normalization and oxide normalization. These two normalization processes alongside finite-element-method simulations are necessary to characterize the bias-dependent response of Si NWs. After applying both normalization methods on open-circuit NWs, which results in a baseline of zero, we conclude that we have accounted for all the major contributions to CPDs and we can isolate effects due to applied bias such as impurity states and charged carrier flow, as well as find open connections when NWs are connected in parallel. These characterization and normalization methods can also be used to determine that the specific contact resistance of electrodes to the NWs is on the order of ?? cm². Thus, the VLS growth method between predefined electrodes overcomes the challenge of making low-resistance contacts to nanoscale systems. Thereby, the experiments and analysis presented outline a systematic method for characterizing nanowires in parallel arrays under device operation conditions. PMID:23609527

Quitoriano, Nathaniel J; Sanderson, Robert N; Bae, Sung-Soo; Ragan, Regina

2013-05-24

98

Essential role of catalysts (Mn, Au, and Sn) in the vapor liquid solid growth kinematics of ZnS nanowires  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate that surface energy of the catalyst is a vital parameter for the growth rate, self doping of the self assembled nanowires synthesized by employing vapor liquid solid growth technique. The synthesis of ZnS nanowires was done by selectively using three different catalysts (Mn, Au, and Sn), where Au, is the most common catalyst, was used as a reference. The distinctive difference in the growth rate was due to the surface energy of the metal alloy droplet and the interface energies, as explained theoretically using thermodynamic approach. We have found that the activation energy of diffusion of (Zn, S) species in the catalyst droplet was low in Sn (0.41 eV for Zn and 0.13 eV for S) and high in Mn (1.79 eV for Zn and 0.61 eV for S) compared to Au (0.62 eV for Zn and 0.21 eV for S) catalyzed ZnS nanostructures. The thermodynamic calculations predicted the growth rates of Sn (7.5 nm/s) catalyzed nanowires was faster than Au (5.1 nm/s) and Mn (4.6 nm/s) catalyzed ZnS nanostructures, which were in agreement with the experimental results. Finally, the location of the catalyst as dopant in the grown nanostructure was predicted and compared with experimental observations.

Rehman, S.; Shehzad, M. A.; Hafeez, M.; Bhatti, A. S.

2014-01-01

99

3D analysis of vapor-liquid two phase flow based on compressible two fluid-one pressure model  

SciTech Connect

General problems were investigated relating to the numerical methodologies in simulating a vapor-liquid two phase flow field based on the two fluid-one pressure model. Major difficulties are caused by the wide time constant range of dominant processes included in the phenomenon. This numerical stiffness problem was solved by applying the implicit method for the interfacial interaction and density wave propagation processes. Fluid state variables were derived by Newton-Raphson iteration method after solving the pressure equation. Several pressure iteration schemes were compared their performance in combination with the outer Newton-Raphson loop. Among them, it was found that the MILUCR scheme is most effective. The isolated cylinder sample calculation indicates that the void localization is mainly caused by the vapor mobility. The k-e model was applied to simulate turbulent effects, which enhanced the above-mentioned trend. The detailed BWR spacer samples indicate that the vapor acceleration and its winding motion is notable in the complex structures.

Hotta, A. [Toden Software, Inc., Minato-ku, Tokyo (Japan)

1995-12-31

100

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

101

Vapor-liquid activity coefficients for methanol and ethanol from heat of solution data: application to steam-methane reforming.  

PubMed

This paper presents equations and curves to calculate vapor-liquid phase equilibria for methanol and ethanol in dilute aqueous solution as a function of temperature, using activity coefficients at infinite dilution. These thermodynamic functions were originally derived to assess the distribution of by-product contaminants in the process condensate and the steam-system deaerator of a hydrogen plant [Paper ENV-00-171 presented at the NPRA 2000 Environmental Conference, San Antonio, TX, 10-12 September 2000], but have general applicability to other systems as well. The functions and calculation method described here are a necessary piece of an overall prediction technique to estimate atmospheric emissions from the deaerator-vent when the process condensate is recycled as boiler feed water (BFW) make-up. Having such an estimation technique is of particular significance at this time because deaerator-vent emissions are already coming under regulatory scrutiny in California [Emissions from Hydrogen Plant Process Vents, Adopted 21 January 2000] followed closely elsewhere in the US, and eventually worldwide. The overall technique will enable a permit applicant to estimate environmental emissions to comply with upcoming regulations, and a regulatory agency to evaluate those estimates. It may also be useful to process engineers as a tool to estimate contaminant concentrations and flow rates in internal process streams such as the steam-generating system. Metallurgists and corrosion engineers might be able to use the results for materials selection. PMID:11606240

Kunz, R G; Baade, W F

2001-11-16

102

Epitaxy-enabled vapor-liquid-solid growth of tin-doped indium oxide nanowires with controlled orientations.  

PubMed

Controlling the morphology of nanowires in bottom-up synthesis and assembling them on planar substrates is of tremendous importance for device applications in electronics, photonics, sensing and energy conversion. To date, however, there remain challenges in reliably achieving these goals of orientation-controlled nanowire synthesis and assembly. Here we report that growth of planar, vertical and randomly oriented tin-doped indium oxide (ITO) nanowires can be realized on yttria-stabilized zirconia (YSZ) substrates via the epitaxy-assisted vapor-liquid-solid (VLS) mechanism, by simply regulating the growth conditions, in particular the growth temperature. This robust control on nanowire orientation is facilitated by the small lattice mismatch of 1.6% between ITO and YSZ. Further control of the orientation, symmetry and shape of the nanowires can be achieved by using YSZ substrates with (110) and (111), in addition to (100) surfaces. Based on these insights, we succeed in growing regular arrays of planar ITO nanowires from patterned catalyst nanoparticles. Overall, our discovery of unprecedented orientation control in ITO nanowires advances the general VLS synthesis, providing a robust epitaxy-based approach toward rational synthesis of nanowires. PMID:24971997

Shen, Youde; Turner, Stuart; Yang, Ping; Van Tendeloo, Gustaaf; Lebedev, Oleg I; Wu, Tom

2014-08-13

103

Interpreting Kelvin probe force microscopy under an applied electric field: local electronic behavior of vapor-liquid-solid Si nanowires  

NASA Astrophysics Data System (ADS)

Kelvin probe force microscopy (KPFM) is used to characterize the electrical characteristics of vapor-liquid-solid (VLS) Si nanowires (NWs) that are grown in-place between two predefined electrodes. KPFM measurements are performed under an applied bias. Besides contact potential differences due to differing materials, the two other primary contributions to measured variations on Si NWs between electrodes are: trapped charges at interfaces, and the parallel and serial capacitance, which are accounted for with voltage normalization and oxide normalization. These two normalization processes alongside finite-element-method simulations are necessary to characterize the bias-dependent response of Si NWs. After applying both normalization methods on open-circuit NWs, which results in a baseline of zero, we conclude that we have accounted for all the major contributions to CPDs and we can isolate effects due to applied bias such as impurity states and charged carrier flow, as well as find open connections when NWs are connected in parallel. These characterization and normalization methods can also be used to determine that the specific contact resistance of electrodes to the NWs is on the order of ?? cm2. Thus, the VLS growth method between predefined electrodes overcomes the challenge of making low-resistance contacts to nanoscale systems. Thereby, the experiments and analysis presented outline a systematic method for characterizing nanowires in parallel arrays under device operation conditions.

Quitoriano, Nathaniel J.; Sanderson, Robert N.; Bae, Sung-Soo; Ragan, Regina

2013-05-01

104

A model of vapor-liquid equilibria in acid gas: Aqueous alkanolamine systems using the electrolyte-NRTL equation  

SciTech Connect

In this paper a thermodynamically-consistent model is developed for representing vapor-liquid equilibria in the acid gas (H/sub 2/S, CO/sub 2/)-alkanolamine-water system. The model accounts for chemical equilibria in a rigorous manner. Activity coefficients are represented with the Electrolyte-NRTL equation, treating both long-range ion-ion interactions and short-range interactions between all true liquid phase species. Both water and alkanolamine are treated as solvents. Adjustable parameters of the Electrolyte-NRTL equation, representing short-range binary interactions, are fitted primarily on binary and ternary system VLE data. Calculated vapor pressures of H/sub 2/S or CO/sub 2/ over aqueous solutions of monoethanolamine or diethanolamine generally agree with published experimental data within 10 percent over the temperature range 25-120{sup 0}C. No more than two additional parameters are adjusted on quartenary system VLE data to provide a good representation of H/sub 2/S and CO/sub 2/ vapor pressures over the same alkanolamine solutions.

Austgen, D.M.; Rochelle, G.T. (Univ. of Texas at Austin, TX (US)); (Peng, X. (Sinopen Beijing Design Institute (US)); Chen, C.C. (Aspen Technology, Inc. TX (US)))

1988-01-01

105

Thermal conductivity of vapor-liquid-solid and vapor-solid silicon carbide whisker-reinforced lithium aluminosilicate glass-ceramic composites  

Microsoft Academic Search

The thermal conductivities of two lithium aluminosilicate glass-ceramic matrix composites reinforced with 30 vol% of either SiC VS (rice hull) whiskers or SiC VLS (vapor-liquid-solid) whiskers were determined form room temperature to 500 C. Because of the preferred alignment of the whiskers, the thermal conductivity values normal to the hot-pressing direction were found to be significantly higher than those in

D. P. H. Hasselman; K. Y. Donaldson; J. R. Jr. Thomas; J. J. Brennan

1996-01-01

106

Isothermal vapor-liquid equilibria for 2-propanol + octane and 2-propanol + 2,2,4-trimethylpentane at 348.15 K  

Microsoft Academic Search

Isothermal vapor-liquid equilibria were measured for 2-propanol + octane and 2-propanol + 2,2,4-trimethylpentane at 348.15 K. The measurements were made in a Rogalski-Malanowski-type still with circulation of both vapor and liquid phases. Both binary isothermal systems form a maximum pressure azeotrope. The azeotropic data are x1(AZ) = 0.882 mole fraction and P(AZ) = 78.20 kPa for 2-propanol (1) + octane

Toshihiko Hiaki; Tomoya Tsuji; Masaru Hongo

1996-01-01

107

Vapor-liquid equilibria of ethanol + 2,2,4-trimethylpentane at 333. 15 K and 1-propanol + 2,2,4-trimethylpentane at 343. 15 K  

Microsoft Academic Search

Isothermal vapor-liquid equilibria were measured for ethanol + 2,2,4-trimethylpentane at 333.15 K and 1-propanol + 2,2,4-trimethylpentane at 343.15 K. The measurements were made in a still with the aid of a computer for control of the temperature and measurement of the total pressure. The experimental results were best correlated with the Wilson equation.

Toshihiko Hiaki; Kenji Takahashi; Tomoya Tsuji; Masaru Hongo; Kazuo Kojima

1994-01-01

108

Study of the Vapor-Liquid Coexistence Curve and the Critical Curve for Nonazeotropic Refrigerant Mixture R152a + R114 System  

NASA Astrophysics Data System (ADS)

Measurements of the vapor-liquid coexistence curve in the critical region for the refrigerant mixture of R152a (CH3CHF2: 1, l-difluoroethane) +R 114 (CCIF2CCIF2 :1, 2-dichloro-1, 1, 2, 2-tetrafluoroethane) system were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Forty-eight saturated densities along the vapor-liquid coexistence curve between 204 and 861 kg·m-3 for five different compositions of 10, 20, 50, 80 and 90 wt% R 152a were obtained in the temperature range 370 to 409 K. The experimental errors of temperature, density, and mass fraction were estimated within ±10mK, ±0.5% and +0.05 %, respectively. On the basis of these measurements, the critical parameters of five different compositions for the R 152a +R 114 system were determined in consideration of the meniscus disappearance level as well as intensity of the critical opalescence. In accordance with the previous results of three other refrigerant mixtures, i.e., R 12 +R 22 system, R 22 +R 114 system and R 13B1 + R 114 system, the coexistence curve and critical curve on the temperature-density diagram for binary refrigerant mixtures were discussed. In addition, correlations of its composition dependence for this system were proposed.

Kabata, Yasuo; Higashi, Yukihiro; Uematsu, Masahiko; Watanabe, Koichi

109

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

NASA Astrophysics Data System (ADS)

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

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

110

Vaporizing liquid microthruster  

Microsoft Academic Search

MEMS technology is expanding into increasingly diverse applications. As part of a micropropulsion system, microthruster attitude controls have been micromachined in silicon. This paper presents the microthruster design, fabrication, and test results. Fluid injected into a microchamber is vaporized by resistive silicon heaters. The exiting vapor generates the thruster force as it exits a silicon micro-nozzle. The vaporization chamber, inlet

E. V Mukerjee; A. P Wallace; K. Y Yan; D. W Howard; R. L Smith; S. D Collins

2000-01-01

111

Step-flow growth of a nanowire in the vapor-liquid-solid and vapor-solid-solid processes  

NASA Astrophysics Data System (ADS)

Consider the growth of a nanowire by a step-flow mechanism in the course of vapor-liquid-solid and vapor-solid-solid processes. The growth is initiated by the nucleation of a circular step at the nanowire-catalyst interface near the edge of the nanowire (the triple junction) and proceeds by the propagation toward the center by the Burton-Cabrera-Frank mechanism. Two cases are considered: (i) bulk transport, where the interfacial diffusion of adatoms and the step motion are coupled to the diffusion flux of atoms from the bulk of the catalyst particle, and (ii) surface transport, where atoms from the vapor phase are adsorbed at the surface of the catalyst particle and diffuse along the surface toward the triple line, whence they diffuse to the nanowire-catalyst interface. The attachment kinetics of adatoms at the step, the adsorption kinetics of atoms from the bulk phase, the exchange kinetics at the triple contact line, and the capillarity of the step are taken into account. In case (i) the problem is reduced to an integral equation for the diffusion flux of atoms from the bulk phase to the nanowire-catalyst interface. This equation is solved numerically, and the flux, interfacial concentration of adatoms, and the bulk concentration near the interface are determined. The step velocity is calculated as a function of the step radius and the kinetic parameters. As a result, the growth rate of a nanowire is computed as a function of its radius. In case (ii) analytical solutions for the surface and interfacial concentrations are obtained. In the absence of step capillarity, an analytical formula for the dependence of the nanowire growth rate on the nanowire radius is derived. It is shown in both cases (i) and (ii) that the nanowire growth rate decreases with increasing nanowire radius due to the decrease in the magnitude of the concentration gradients. However, in case (ii), in the limit of negligible desorption of adatoms into the gas phase, the nanowire growth rate is independent of the radius. It is also shown that in the presence of step capillarity (the Gibbs-Thomson effect) increases the nanowire growth rate.

Golovin, A. A.; Davis, S. H.; Voorhees, P. W.

2008-10-01

112

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

SciTech Connect

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.

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

2012-07-30

113

A study of contacts to p- and n-type silicon nanowires synthesized via vapor-liquid-solid growth process  

NASA Astrophysics Data System (ADS)

Silicon nanowires have been the subject of intense research in recent years for their potential application in future nanoscale electronic systems and for studying physical phenomena in restricted geometries. In order for nanoscale electronic devices to realize their full potential in certain applications, ohmic contacts are required. The present study focuses on the fabrication and characterization of electrical contacts to p- and n-type Si nanowires grown by the vapor-liquid-solid method with the objective of designing ohmic contacts with a low contact resistance. The actual contacts to these nanowires could exist in two possible geometries: firstly, as an integral part of the nanowires fabricated during growth of the nanowires, also referred to as nanowire heterojunction contacts, and secondly, in the form of lithographically defined metal pads overlapping the nanowires. Cobalt silicide/Si and Au/Si heterojunction nanowires grown in anodized alumina templates with an average pore diameter of 200 nm were studied in the former geometry. An optimum amount of Au catalyst was deemed necessary for obtaining cobalt silicide/Si nanowires with good morphology. Investigations using transmission electron microscopy helped determine this amount to be approximately two-thirds of the average pore diameter of the templates in which the nanowires were grown. Subsequently, detailed scanning transmission electron microscopy revealed that even some of the nanowires with good morphology contained Au nanoparticles, more so near the interface of the Si segment with the silicide in the case of cobalt silicide/Si nanowires and with the Au in the case of Au/Si nanowires. Such Au nanoparticles were shown to cause discontinuities in some nanowires upon annealing at temperatures above the Au-Si eutectic point. Nanowires grown out the top of the membranes contained very few Au nanoparticles away from the Au/Si interface and were used for studying contacts in the metal-pad geometry. Contacts in a two-point probe configuration based on Pd, Ti/Au and Co/Al metallizations were studied for heavily doped p-type Si nanowires of average diameter 80 nm that were grown out the top of membranes, and a Ti/Au metallization was studied for heavily doped n-type Si nanowires of similar diameter. Such studies revealed that for p-type nanowires, the Co/Al contacts were the least resistive under similar fabrication and annealing conditions. Annealing from 200--300°C in a N2 ambient was shown to be optimal for obtaining ohmic contacts and avoiding thermal degradation. For n-type nanowires, the Ti/Au contacts were also shown to form ohmic contacts readily upon annealing between 250--300°C under similar conditions. Field emission scanning electron microscopy was used to study some of the defective p- and n-type Si nanowire devices including contact electrodes. A multi-contact test structure was next fabricated, which made it possible to extract various contact parameters based on a nanowire transmission line model. Contacts based on Al, Co and Co/Al metallizations were fabricated on heavily doped p-type nanowires of average diameter 80 nm that were grown out the top of membranes and from Au thin films, and an Er/Al metallization was used for heavily doped n-type nanowires of similar diameter grown by similar methods. The specific contact resistance of as-deposited Al contacts was found to be within 1 x 10-5 -- 4 x 10-4 O-cm2 when extracted at the origin of the device current-voltage (I-V) characteristics for p-type Si nanowires of resistivity 0.53 (+/-0.48) O-cm. Cobalt contacts, upon annealing in N2 within 250--300°C in the multicontact fabrication, showed lower resistance and more linear current-voltage characteristics than the Al contacts but were more difficult to lift off at the required metallization thickness. A contact based on the Co/Al metallization was later fabricated that combined the ease of lift-off of the Al multicontacts with the low resistance of the annealed Co contacts. The specific contact resistance of ohmic contacts based on such a metallizat

Dey, Soham

114

Very low specific contact resistance measurements made on a highly p-type doped 4H-SiC layer selectively grown by vapor-liquid-solid transport  

NASA Astrophysics Data System (ADS)

This work reports on the performances of ohmic contacts fabricated on highly p-type doped 4H-SiC epitaxial layer selectively grown by vapor-liquid-solid transport. Due to the very high doping level obtained, the contacts have an ohmic behavior even without any annealing process. Upon variation of annealing temperatures, it was shown that both 500 and 800 °C annealing temperature lead to a minimum value of the Specific Contact Resistance (SCR) down to 1.3×10-6 ??cm2. However, a large variation of the minimum SCR values has been observed (up to 4×10-4 ??cm2). Possible sources of this fluctuation have been also discussed in this paper.

Thierry-Jebali, N.; Vo-Ha, A.; Carole, D.; Lazar, M.; Ferro, G.; Planson, D.; Henry, A.; Brosselard, P.

2013-05-01

115

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)

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.

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

1977-01-01

116

Constraints on the relativistic mean field of ?-isobar in nuclear matter  

NASA Astrophysics Data System (ADS)

The effects of the presence of ?-isobars in nuclear matter are studied in the framework of relativistic mean-field theory. The existence of stable nuclei at saturation density imposes constraints on the ?-isobar self-energy and thereby on the mean-field coupling constants of the scalar and vector mesons with ?-isobars. The range of possible values for the scalar and vector coupling constants of ?-isobars with respect to the nucleon coupling is investigated and compared to recent predictions of QCD sum-rule calculations.

Kosov, D. S.; Fuchs, C.; Martemyanov, B. V.; Faessler, Amand

1998-03-01

117

Sensitive dependence of isotope and isobar distribution of limiting temperatures on symmetry energy  

E-print Network

The mass, isotope, and isobar distributions of limiting temperatures for finite nuclei are investigated by using a thermodynamics approach together with the Skyrme energy density functional. The relationship between the width of the isotope (isobar) distribution of limiting temperatures and the stiffness of the density dependence of the symmetry energy clearly is observed. The nuclear symmetry energy with smaller slope parameter $L_{\\rm{sym}}$ causes a wider the isotope (isobar) distribution of limiting temperatures. The widths of the isotope (isobar) distributions of limiting temperatures could be useful observables for exploring the information of the density dependence of the nuclear symmetry energy at finite temperatures.

Li Ou; Min Liu; Zhuxia Li

2014-02-10

118

Hard breakup of the deuteron into two Delta-isobars  

E-print Network

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 the 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 $pn\\rightarrow \\Delta\\Delta$ 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 $pn\\rightarrow \\Delta\\Delta$ scattering. We predict that the cross section of the deuteron breakup to $ \\Delta^{++}\\Delta^{-}$ is 4-5 times larger than that of the breakup to the $ \\Delta^{+}\\Delta^{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^{++}\\Delta^{-}$ and $ \\Delta^{+}\\Delta^{0}$ channels to be similar.

Carlos G. Granados; Misak M. Sargsian

2011-04-20

119

Hard breakup of the deuteron into two ? isobars  

NASA Astrophysics Data System (ADS)

We study high-energy photodisintegration of the deuteron into two ? 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??? 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??? scattering. We predict that the cross section of the deuteron breakup to ?++?- is 4-5 times larger than that of the breakup to the ?+?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 ? isobars are the result of the disintegration of the preexisting ?? components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels to be similar.

Granados, Carlos G.; Sargsian, Misak M.

2011-05-01

120

Hard breakup of the deuteron into two ? -isobars  

NASA Astrophysics Data System (ADS)

Photodisintegration of the deuteron into two ?-isobars at large center of mass angles is studied within the QCD hard rescattering model (HRM). According to the HRM, the reaction proceeds in three main steps: the photon knocks the 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 emerging at large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn->?? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. We predict that the cross section of the deuteron breakup to &++circ;&-circ; is 4-5 times larger than that of the breakup to the &+circ;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 ?-isobars are the result of the disintegration of initial ?? components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both &++circ;&-circ; and &+circ;0? channels are expected to be similar.

Granados, Carlos; Sargsian, Misak

2011-04-01

121

An objective isobaric/isentropic technique for upper air analysis  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

122

Shear viscosity and thermal conductivity of dipolar real fluids from equilibrium molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

Equilibrium molecular dynamics and the Green-Kubo formalism were used to simultaneously calculate shear viscosity and thermal conductivity for 10 refrigerants: R11, R12, R22, R23, R41, R123, R134a, R142b, R143a, and R152a. The fluids were modelled in previous work of Stoll et al. [J Chem Phys 2003;119:11396-407] using the two-center Lennard-Jones plus point dipole (2CLJD) pair potential, with parameters adjusted to vapor-liquid equilibria only. The predicted shear viscosities and thermal conductivities show an overall average deviation of about 15% and 10%, respectively, from correlations of experimental data.

Fernández, Gimmy A.; Vrabec, Jadran; Hasse, Hans

2006-10-01

123

Partition Equilibrium  

Microsoft Academic Search

We introduce partition equilibrium and study its existence in resource selection games (RSG). In partition equilibrium the\\u000a agents are partitioned into coalitions, and only deviations by the prescribed coalitions are considered. This is in difference\\u000a to the classical concept of strong equilibrium according to which any subset of the agents may deviate. In resource selection\\u000a games, each agent selects a

Michal Feldman; Moshe Tennenholtz

2009-01-01

124

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

NASA Astrophysics Data System (ADS)

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.

Islam, Md. Shofiqul; Ishida, Makoto

2015-01-01

125

Effect of vapor-liquid-solid and vapor-solid silicon carbide whiskers on the effective thermal diffusivity/conductivity of silicon nitride matrix composites  

SciTech Connect

This paper reports on a study that was conducted of relative effect of vapor-liquid-solid (VLS) and vapor-solid (VS) SiC whiskers on the effective thermal diffusivity and conductivity of pressed-densified silicon nitride. It was found that VLS whiskers cause an increase in the thermal diffusivity/conductivity, whereas the opposite effect was found for the VS-SiC whiskers. Comparison with composite theory suggests that the VS-SiC whiskers have a thermal conductivity as low as 25 to 30 W/(m {center dot} K). In contrast the VLS-SiC whiskers appear to have a value for the thermal conductivity of at least about 100 W/(m{center dot} K) to as high as 250 W/(m {center dot} K). These large differences in thermal conductivity for these two types of SiC whiskers are attributed to the much larger density of structural defects in the VS-SiC whiskers, which act as phonon scatterers, thereby lowering the thermal conductivity.

Russell, L.M.; Donaldson, K.Y.; Hasselman, D.H. (Dept. of Materials Engineering, Virginia Polytechnic Inst., Blacksbury, VA (US)); Corbin, N.D. (Norton Co., Northborough, MA (US)); Petrovic, J.J. (Los Alamos National Lab., Los Alamos, NM (US)); Rhodes, J.F. (Advanced Composite Materials Corp., Greer, SC (US))

1991-04-01

126

Thermal conductivity of vapor-liquid-solid and vapor-solid silicon carbide whisker-reinforced lithium aluminosilicate glass-ceramic composites  

SciTech Connect

The thermal conductivities of two lithium aluminosilicate glass-ceramic matrix composites reinforced with 30 vol% of either SiC VS (rice hull) whiskers or SiC VLS (vapor-liquid-solid) whiskers were determined form room temperature to 500 C. Because of the preferred alignment of the whiskers, the thermal conductivity values normal to the hot-pressing direction were found to be significantly higher than those in the parallel direction. The composites with the VLS whiskers exhibited higher thermal conductivity values than those with the VS whiskers. An analysis of the room-temperature data showed that the thermal conductivity values parallel to the hot-pressing direction were higher than those predicted from theory, even for whiskers with infinite thermal conductivity and perfect interfacial thermal contact. This effect was attributed to a significant contribution of percolation to the total heat flow as a result of direct whisker-to-whisker contact. For both types of whiskers, the interfacial thermal conductance and thermal conductivity value (at {approx} 6.5 {times} 10{sup 5} W/(m{sup 2}{center_dot}K) and 200 W/(m{center_dot}K), respectively) inferred from the composite thermal conductivity values perpendicular to the hot-pressing direction were essentially the same. It was concluded that the order of magnitude difference in thickness for the two whisker types was primarily responsible for the differences in thermal conductivity measured for these two composites.

Hasselman, D.P.H.; Donaldson, K.Y. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Thomas, J.R. Jr. [Los Alamos National Lab., NM (United States). Ceramic Science and Technology Group; Brennan, J.J. [United Technologies Research Center, East Hartford, CT (United States)

1996-03-01

127

The isobaric multiplet mass equation for A?71 revisited  

SciTech Connect

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.

Lam, Yi Hua, E-mail: lamyihua@gmail.com [CENBG (UMR 5797 — Université Bordeaux 1 — CNRS/IN2P3), Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France); Blank, Bertram, E-mail: blank@cenbg.in2p3.fr [CENBG (UMR 5797 — Université Bordeaux 1 — CNRS/IN2P3), Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France)] [CENBG (UMR 5797 — Université Bordeaux 1 — CNRS/IN2P3), Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France); Smirnova, Nadezda A. [CENBG (UMR 5797 — Université Bordeaux 1 — CNRS/IN2P3), Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France)] [CENBG (UMR 5797 — Université Bordeaux 1 — CNRS/IN2P3), Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan Cedex (France); Bueb, Jean Bernard; Antony, Maria Susai [IPHC, Université de Strasbourg, CNRS/UMR7178, 23 Rue du Loess, 67037 Strasbourg Cedex (France)] [IPHC, Université de Strasbourg, CNRS/UMR7178, 23 Rue du Loess, 67037 Strasbourg Cedex (France)

2013-11-15

128

Isobaric molecular dynamics simulations of hard sphere systems.  

PubMed

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. PMID:11415067

Gruhn, T; Monson, P A

2001-06-01

129

Hard breakup of the deuteron into two {Delta} isobars  

SciTech Connect

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.

Granados, Carlos G.; Sargsian, Misak M. [Florida International University, Miami, Florida 33199 (United States)

2011-05-15

130

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

NASA Astrophysics Data System (ADS)

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 CH2 and CH3 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.

Ghobadi, Ahmadreza F.; Elliott, J. Richard

2014-07-01

131

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

NASA Astrophysics Data System (ADS)

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.

Yuan, S. W. K.

132

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)

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.

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

2014-08-01

133

Hard breakup of the deuteron into two $\\Delta$-isobars  

E-print Network

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 the 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 produced at large transverse momenta. Within the HRM the cross section is expressed through the amplitude of $pn\\rightarrow \\Delta\\Delta$ 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 $pn\\rightarrow \\Delta\\Delta$ scattering. We predict a cross section for the deuteron breakup to $ \\Delta^{++}\\Delta^{-}$ a factor of 4-5 times larger than that for the breakup to the $ \\Delta^{-}...

Granados, Carlos G

2010-01-01

134

Glycan Analysis by Isobaric Aldehyde Reactive Tags and Mass Spectrometry  

PubMed Central

Glycans play significant roles in physiological and pathological processes. Therefore, quantitative analysis of glycans from normal and disease specimens can provide insight into disease onset and progression. Relative glycan quantification usually requires modification of the glycans with either chromogenic or fluorogenic tags for optical measurement or isotopic tags for mass spectrometric analysis. Due to rapid advances in mass spectrometry (MS) instruments in resolution, sensitivity and speed, MS-based methods have become increasingly popular for glycan analysis in the past decade. However, current isotopic tags for glycan labeling are mostly mass-shift tags generating mass differences in precursor ions for quantification, which can complicate mass spectra. In this study, we report the synthesis and characterization of isobaric aldehyde reactive tags (iARTs) for glycan quantification using tandem MS. We applied iARTs to the relative identification and quantification of glycans of gp120, a glycoprotein from human immunodeficiency virus. The results show that iARTs provide strong signals for glycan identification. Although we only show the synthesis and characterization of two iARTs reagents, iARTs can be readily expanded to six-plex tags for quantitative analysis of six samples concurrently. PMID:23895018

Yang, Shuang; Yuan, Wei; Yang, Weiming; Zhou, Jianying; Harlan, Robert; Edwards, James; Li, Shuwei; Zhang, Hui

2013-01-01

135

Deformation effects on isospin mixing and isobar analogue resonance for 74-80Kr isotopes  

NASA Astrophysics Data System (ADS)

Pyatov's method has been applied to investigate Fermi beta transitions in deformed 74-80Kr isotopes. This self-consistent method, which was used to study the isobar analogue states in the spherical odd-odd nuclei, has to date not been applied for the isobar analogue states in deformed nuclei. The nucleon-nucleon residual interaction has been included so that the broken isospin symmetry in the mean field approximation has been restored and the strength parameter of the effective interaction has been taken out to be a free parameter. The energies and wave functions of the isobaric analogue excitations in 74-80Rb isotopes have been obtained within the framework of the pnQRPA method. The probability of the isospin mixing in the ground states and the centroid energies of the isobar analogue resonance have been presented and the deformation effects on these quantities have been quantified.

Aygör, Hasan A.; Ünlü, Serdar; Çakmak, Neçla; Selam, Cevat

2014-07-01

136

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)

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.

Plyasunov, Andrey V.

2012-01-01

137

Equilibrium solubilities of CO/sub 2/ and H/sub 2/S in diethanolamine (DEA) and methyldiethanolamine (MDEA) solutions  

SciTech Connect

The ability to predict equilibrium phase behavior in systems containing CO/sub 2/ and/or H/sub 2/S in alkanolamine solutions such as diethanolamine (DEA) and methyldiethanolamine (MDEA) is of vital importance for proper design and operation of acid gases treating systems. Literature data for the solubilities of CO/sub 2/ and/or H/sub 2/S in DEA and MDEA systems have been compiled and evaluated. Experimental measurements have also been made to confirm literature data and to expand the data base. A vapor-liquid equilibrium (VLE) model similar to the one developed by Kent and Eisenberg has been developed to correlate the data. The model gives the most accurate predictions when compared to other VLE models available for predicting equilibrium acid gas partial pressures over DEA and MDEA solutions.

Ho, A.S.; Equren, P.R. (Amoco Production Co., Tulsa, OK (US))

1988-01-01

138

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

139

Interference-free proteome quantification with MS/MS-based isobaric isotopologue detection.  

PubMed

Chemical labeling of peptides prior to shotgun proteomics allows relative quantification of proteins in biological samples independent of sample origin. Current strategies utilize isobaric labels that fragment into reporter ions. However, quantification of reporter ions results in distorted ratio measurements due to contaminating peptides that are co-selected in the same precursor isolation window. Here, we show that quantitation of isobaric peptide fragment isotopologues in tandem mass spectra reduces precursor interference. The method is based on the relative quantitation of isobaric isotopologues of dimethylated peptide fragments in tandem mass spectra following higher energy collisional dissociation (HCD). The approach enables precise quantification of a proteome down to single spectra per protein and quantifies >90% of proteins in a MudPIT experiment and accurately measures proteins in a model cell line for cystic fibrosis. PMID:24417624

Bamberger, Casimir; Pankow, Sandra; Park, Sung Kyu Robin; Yates, John R

2014-03-01

140

Cost-effective isobaric tagging for quantitative phosphoproteomics using DiART reagents.  

PubMed

We describe the use of an isobaric tagging reagent, Deuterium isobaric Amine Reactive Tag (DiART), for quantitative phosphoproteomic experiments. Using DiART tagged custom mixtures of two phosphorylated peptides from alpha casein and their non-phosphorylated counterparts, we demonstrate the compatibility of DiART with TiO2 affinity purification of phosphorylated peptides. Comparison of theoretical vs. experimental reporter ion ratios reveals accurate quantification of phosphorylated peptides over a dynamic range of more than 15-fold. Using DiART labelling and TiO2 enrichment (DiART-TiO2) with large quantities of proteins (8 mg) from the cell lysate of model fungus Aspergillus nidulans, we quantified 744 unique phosphopeptides. Overlap of median values of TiO2 enriched phosphopeptides with theoretical values indicates accurate trends. Altogether these findings confirm the feasibility of performing quantitative phosphoproteomic experiments in a cost-effective manner using isobaric tagging reagents, DiART. PMID:24129742

Ramsubramaniam, Nikhil; Tao, Feng; Li, Shuwei; Marten, Mark R

2013-12-01

141

IQuant: an automated pipeline for quantitative proteomics based upon isobaric tags.  

PubMed

Quantitative proteomics technology based on isobaric tags is playing an important role in proteomic investigation. In this paper, we present an automated software, named IQuant, which integrates a postprocessing tool of protein identification and advanced statistical algorithms to process the MS/MS signals generated from the peptides labeled by isobaric tags and aims at proteomics quantification. The software of IQuant, which is freely downloaded at http://sourceforge.net/projects/iquant/, can run from a graphical user interface and a command-line interface, and can work on both Windows and Linux systems. PMID:25069810

Wen, Bo; Zhou, Ruo; Feng, Qiang; Wang, Quanhui; Wang, Jun; Liu, Siqi

2014-10-01

142

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

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

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

2006-07-21

143

2 -Equilibrium States 1. Thermal Equilibrium  

E-print Network

1 2 - Equilibrium States 1. Thermal Equilibrium Detailed balancing for interacting systems energy E1E2 = energy E2E1 Atomic Energy Levels Matter particles only "mechanical equilibrium" Matter + Radiation "thermodynamic equilibrium" ­ "TE" In TE, all distributions are homogeneous and isotropic

Sitko, Michael L.

144

4 -Equilibrium States 1. Thermal Equilibrium  

E-print Network

1 4 - Equilibrium States 1. Thermal Equilibrium Detailed balancing for interacting systems energy E1 E2 = energy E2 E1 Atomic Energy Levels Matter particles only "mechanical equilibrium" Matter + Radiation "thermodynamic equilibrium" ­ "TE" In TE, all distributions are homogeneous and isotropic, and can

Sitko, Michael L.

145

Tandem Mass Spectrometric Analysis of a Mixture of Isobars Using the Survival Yield Technique  

NASA Astrophysics Data System (ADS)

Collision induced dissociation tandem mass spectrometry experiments were performed to unequivocally separate compounds from an isobaric mixture of two products. The Survival Yield curve was obtained and is shown to consist in a linear combination of the curves corresponding to the two components separately. For such a mixture, a plateau appears on the diagram in lieu of the continuous decrease expected allowing for the structural study of the two components separately. The width of the plateau critically relates to the fragmentation parameters of the two molecular ions, which need to be sufficiently different structurally for the plateau to be observed. However, at constant fragmentation parameters, we have observed the width significantly increases at large m/z. This makes the separation more and more efficient as isobars have larger m/z and the technique complementary to those applicable at low m/z only. We have observed that the vertical position of the plateau relates linearly to the relative concentration of the two compounds that may be useful for quantification. Repeatability was estimated at 2% on a quadrupole ion trap. An advantage of using survival yield curves only, is that a priori knowledge of the respective fragmentation patterns of the two isobars becomes unnecessary. Consequently, similar performances are obtained if fragments are isobaric, which is also demonstrated in our study. The critical case of reverse peptides, at low m/z and similar fragmentation parameters, is also presented as a limitation of the method.

Memboeuf, Antony; Jullien, Laure; Lartia, Rémy; Brasme, Bernard; Gimbert, Yves

2011-10-01

146

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

E-print Network

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

Attard, Phil

147

Strategies for differentiation of isobaric flavonoids using liquid chromatography coupled to electrospray ionization mass spectrometry.  

PubMed

Flavonoids are a class of secondary plant metabolites existing in great variety in nature. Due to this variety, identification can be difficult, especially as overlapping compounds in both chromatographic separations and mass spectrometric detection are common. Methods for distinguishing isobaric flavonoids using MS(2) and MS(3) have been developed. Chromatographic separation of various plant extracts was done with RP-HPLC and detected with positive ESI-MS operated in information-dependent acquisition (IDA) mode. Two methods for the determination of flavonoid identity and substitution pattern, both featuring IDA criteria, were used together with the HPLC equipment. A third method where the collision energy was ramped utilized direct infusion. With the developed strategies, it is possible to differentiate between many isobaric flavonoids. Various classes of flavonoids were found in all of the plant extracts, in the red onion extract 45 components were detected and for 29 of them the aglycone was characterized, while the substituents were tentatively identified for 31 of them. For the strawberry extract, those numbers were 66, 30 and 60, and for the cherry extract 99, 56 and 71. The great variety of flavonoids, several of them isobaric, found in each of the extracts highlights the need for reliable methods for flavonoid characterization. Methods capable of differentiating between most of the isobars analyzed have been developed. PMID:25044850

Fridén, Mikael E; Sjöberg, Per J R

2014-07-01

148

Stable carbon and hydrogen isotope fractionation of dissolved organic groundwater pollutants by equilibrium sorption  

NASA Astrophysics Data System (ADS)

Linear free energy relationships (LFERs) were established which relate equilibrium vapor-liquid isotope effects to stable carbon and hydrogen isotope enrichment factors for equilibrium sorption to geosorbents. The LFERs were established for normal, cyclic or branched alkanes, monoaromatic hydrocarbons, and chloroethenes. These LFERs predict that isotopic light compounds sorb more strongly than their heavy counterparts. Defining fractionation as in classical literature by "heavy divided by light", carbon enrichment factors for equilibrium sorption were derived which ranged from - 0.13 ± 0.04‰ (benzene) to - 0.52 ± 0.19‰ (trichloroethene at 5-15 °C). Hydrogen enrichment factors for sorption of 14 different compounds were between - 2.4 and - 9.2‰. For perdeuterated hydrocarbons the predicted enrichment factors ranged from - 19 ± 5.4‰ (benzene) to - 64 ± 30‰ (cyclohexane). Equilibrium sorption experiments with a soil and activated carbon as sorbents were performed in the laboratory for perdeuterocyclohexane and perdeuterotoluene. The measured D/H enrichments agreed with the LFER prediction for both compounds and both sorbents within the uncertainty estimate of the prediction. The results of this work suggest that equilibrium sorption does create only very small isotope shifts for 13C in groundwater pollutants in aquifers. It is also suggested that deuterium shifts are expected to be higher, especially for strongly sorbing pollutants.

Höhener, Patrick; Yu, Xianjing

2012-03-01

149

Sequential Equilibrium and Perfect Equilibrium in Games of Imperfect Recall  

E-print Network

Sequential Equilibrium and Perfect Equilibrium in Games of Imperfect Recall Joseph Y. Halpern, 2008 Abstract Definitions of sequential equilibrium and perfect equilibrium are given in games of imperfect recall. 1 Introduction Sequential equilibrium [Kreps and Wilson 1982] and perfect equilibrium

Keinan, Alon

150

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

E-print Network

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 $\\rm{R_m} \\gtrsim100,000$.

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

151

Small-Dose Intrathecal Clonidine and Isobaric Bupivacaine for Orthopedic Surgery: A Dose-Response Study  

Microsoft Academic Search

We examined the dose-response relationship of intrathe- cal clonidine at small doses (150g) with respect to pro- longing bupivacaine spinal anesthesia. We aimed for es- tablishing doses of intrathecal clonidine that would produce clinically relevant prolongation of spinal anes- thesia and pain relief without significant side effects. Eighty orthopedic patients were randomly assigned to in- trathecally receive isobaric 0.5% bupivacaine,

Stephan Strebel; Markus C. Schneider; Armin Aeschbach; Christoph H. Kindler

2004-01-01

152

Quasi-two-body phase-space factors in the isobar model  

SciTech Connect

We present an integral representation of quasi-two-body phase-space factors in the isobar model, which in general enough to be used in phenomenological partial-wave scattering studies of systems such as ..pi..N, KN, NN, etc. We examine its analytic structure in detail, and furthermore cast it into an analytic form. This integral representation, with its analytic expression, is then convenient for use in analysis work.

Bhandari, R.

1982-03-01

153

Discrimination of large maltooligosaccharides from isobaric dextran and pullulan using ion mobility mass spectrometry  

PubMed Central

RATIONALE Ion mobility mass spectrometry (IMMS) has previously been shown to resolve small isobaric oligosaccharides, but larger alpha-oligoglucans are also abundant in biology and are of industrial importance. If conformational differences between such isomers are retained in the gas phase, IMMS could be used to address questions in biology and industry. METHODS Negative mode electrospray ionization (ESI) travelling-wave IMMS was used to resolve large isobaric ?-glucan ions on the basis of their different gas-phase conformations. ?,?-Dicarboxy-terminated polystyrene was used to calibrate the instrument allowing the collision cross-sections (CCSs) of ions to be determined. RESULTS ?-1,4-Linked maltooligosaccharides with a degree of polymerisation of up to 35 could be discriminated from ?-1,6-linked dextran and ?-1,4/1,6-linked pullulan using IMMS. Fragmentation spectra of ions separated by IMMS could also distinguish isomers. Two conformational isomers of maltohexaose were resolvable by IMMS, likely reflecting extended and V6 helical conformations. IMMS was also able to identify a product within a mixture of maltooligosaccharides treated with the potential anti-tuberculosis drug target Mycobacterium tuberculosis GlgB branching enzyme. CONCLUSIONS Biological samples of complex isobaric oligosaccharides can be analysed using IMMS in the negative mode providing facile analyses and high sensitivity without the need for either derivatisation or chromatographic separation. © 2013 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:24338967

Rashid, Abdul M; Saalbach, Gerhard; Bornemann, Stephen

2013-01-01

154

Noradrenaline-induced depolarization is smaller in isobaric compared to isometric preparations of rat mesenteric small arteries  

Microsoft Academic Search

The hypothesis was tested that wall tension can influence the membrane potential response to noradrenaline (NA) using isometric and isobaric vessel preparations of rat mesenteric small arteries. The resting membrane potential was significantly less negative in the isobaric (?49.7±0.5 mV, S.E.M., n=12 vessels) compared to the isometric preparation (?56.1±0.7 mV, n=10), although there was no difference in wall tension. The

Rudolf Schubert; Jos P. M. Wesselman; Holger Nilsson; Michael J. Mulvany

1996-01-01

155

Relative protein quantification by isobaric SILAC with immonium ion splitting (ISIS).  

PubMed

Metabolic labeling techniques have recently become popular tools for the quantitative profiling of proteomes. Classical stable isotope labeling with amino acids in cell cultures (SILAC) uses pairs of heavy/light isotopic forms of amino acids to introduce predictable mass differences in protein samples to be compared. After proteolysis, pairs of cognate precursor peptides can be correlated, and their intensities can be used for mass spectrometry-based relative protein quantification. We present an alternative SILAC approach by which two cell cultures are grown in media containing isobaric forms of amino acids, labeled either with 13C on the carbonyl (C-1) carbon or 15N on backbone nitrogen. Labeled peptides from both samples have the same nominal mass and nearly identical MS/MS spectra but generate upon fragmentation distinct immonium ions separated by 1 amu. When labeled protein samples are mixed, the intensities of these immonium ions can be used for the relative quantification of the parent proteins. We validated the labeling of cellular proteins with valine, isoleucine, and leucine with coverage of 97% of all tryptic peptides. We improved the sensitivity for the detection of the quantification ions on a pulsing instrument by using a specific fast scan event. The analysis of a protein mixture with a known heavy/light ratio showed reliable quantification. Finally the application of the technique to the analysis of two melanoma cell lines yielded quantitative data consistent with those obtained by a classical two-dimensional DIGE analysis of the same samples. Our method combines the features of the SILAC technique with the advantages of isobaric labeling schemes like iTRAQ. We discuss advantages and disadvantages of isobaric SILAC with immonium ion splitting as well as possible ways to improve it. PMID:18165257

Colzani, Mara; Schütz, Frédéric; Potts, Alexandra; Waridel, Patrice; Quadroni, Manfredo

2008-05-01

156

Kinetics of (6 R , S ) 5-formyltetrahydrofolic acid isobaric–isothermal degradation in a model system  

Microsoft Academic Search

Isothermal and isobaric–isothermal degradation kinetics of (6R,S) 5-formyltetrahydrofolic acid (5-CHOH4PteGlu) was studied at different pH levels in the temperature range from 80 to 110 °C and different pressure–temperature combinations (100–800 MPa and 30–70 °C). The thermal degradation of 5-CHOH4PteGlu followed first-order kinetics at all pH levels (in the range of pH 3–9.2) studied. 5-CHOH4PteGlu at pH 7–9.2 was quite stable up to 5–7 h

M. T. Nguyen; I. Oey; M. Hendrickx; A. van Loey

2006-01-01

157

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

NASA Astrophysics Data System (ADS)

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.

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

158

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

E-print Network

Using the Penning trap mass spectrometer TITAN, we performed the first direct mass measurements of 20,21Mg, 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 six orders of magnitude. Compared to the latest atomic mass evaluation, we find that the mass of 21Mg is in good agreement but that the mass of 20Mg deviates by 3{\\sigma}. These measurements reduce the uncertainties in the masses of 20,21Mg 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 non-conserving USDA/B Hamiltonians or isospin non-conserving interactions based on chiral two- and three-nucleon forces.

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

2014-09-04

159

Differential plant proteome analysis by isobaric tags for relative and absolute quantitation (iTRAQ).  

PubMed

Protein relative quantitation is one of the main targets in many proteomic experiments. Among the range of techniques available for both top-down and bottom-up approaches, isobaric tags for relative and absolute quantitation (iTRAQ) have gained positions within the top-rank techniques used for this purpose in the recent years. Briefly, each iTRAQ reagent consists of three different components: a reporter group (with a variable mass in the range of 114-117 amu), a balance group, and an amino-reactive group. The isobaric nature of iTRAQ-labeled peptides adds a signal to every peptide in the sample which is detectable in both MS and MS/MS spectra, thus enhancing the sensitivity of detection. During MS/MS, the reporter groups are released as singly charged ions with m/z ratios ranking from 114 to 117 amu, visible in the low mass region of MS/MS spectra. The iTRAQ technology can be used to analyze up to four different samples using the 4-plex kit (reporter groups 114-115 amu) or can be scaled up to eight different samples using the 8-plex kit (reporter groups 113-121 amu). In this chapter, we focus on the experimental procedures typically using 4-plex labeling, including tips leading to successful application of iTRAQ technology for the analysis of plant protein mixtures. PMID:24136521

Martínez-Esteso, María J; Casado-Vela, Juan; Sellés-Marchart, Susana; Pedreño, María A; Bru-Martínez, Roque

2014-01-01

160

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

PubMed

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

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

161

Isobaric-isothermal Monte Carlo simulations from first principles: Application to liquid water at ambient conditions  

SciTech Connect

A series of first principles Monte Carlo simulations in the isobaric-isothermal ensemble were carried out for liquid water at ambient conditions (T = 298 K and p = 1 atm). The Becke-Lee-Yang-Parr (BLYP) exchange and correlation energy functionals and norm-conserving Goedecker-Teter-Hutter (GTH) pseudopotentials were employed with the CP2K simulation package to examine systems consisting of 64 water molecules. The fluctuations in the system volume encountered in simulations in the isobaric-isothermal ensemble requires a reconsideration of the suitability of the typical charge density cutoff and the regular grid generation method previously used for the computation of the electrostatic energy in first principles simulations in the microcanonical or canonical ensembles. In particular, it is noted that a much higher cutoff is needed and that the most computationally efficient method of creating grids can result in poor simulations. Analysis of the simulation trajectories using a very large charge density cutoff at 1200 Ry and four different grid generation methods point to a substantially underestimated liquid density of about 0.85 g/cm{sup 3} resulting in a somewhat understructured liquid (with a value of about 2.7 for the height of the first peak in the oxygen/oxygen radial distribution function) for BLYP-GTH water at ambient conditions.

McGrath, M; Siepmann, J I; Kuo, I W; Mundy, C J; VandeVondele, J; Hutter, J; Mohamed, F; Krack, M

2004-12-02

162

Experimental equilibrium and modeling for the absorption of acid gases in diethanolamine solutions at low and high partial pressures  

SciTech Connect

This study was undertaken to develop an experimental apparatus that would allow direct measurements of gas equilibrium solubility in aqueous alkanolamine solutions at low gas partial pressures. Carbon dioxide and hydrogen sulfide solubility in 20, 35 and 50% by weight diethanolamine aqueous solutions was measured. The measurements were made at acid gas partial pressures between 0.003 and 10.9 psia and temperatures of 80, 150 and 240{degree}F. The experimental data at low partial pressure were used in a procedure to correlate them with literature data at high partial pressures and establish a model for carbon dioxide-hydrogen sulfide-aqueous diethanolamine systems. An experimental apparatus was developed to measure the equilibrium solubility of acid gas in diethanolamine solutions at low acid gas partial pressures. The experimental procedure does not require that vapor liquid samples be withdrawn for analysis, so equilibrium in the experimental apparatus is never disturbed. A consistency test for evaluation of experimental acid gas-ethanolamine equilibrium data was developed. The test was shown to apply in the full range of partial pressures where chemical reactions dominate. Predictions of acid gas partial pressures were substantially improved and application to model an integrated high pressure natural gas plant gave good results. The experimental apparatus and the consistency test should be used for other amines of industrial interest to improve the modeling.

Elizondo-Villarreal, E.M.

1989-01-01

163

PIPERADE: A Penning-trap isobar separator for the DESIR low-energy facility of SPIRAL2  

NASA Astrophysics Data System (ADS)

A Penning-trap isobar separator is currently under construction at CENBG (Bordeaux, France) and MPIK (Heidelberg, Germany) for a future installation at the SPIRAL2/DESIR facility. This device aims at purifying the radioactive ion beams from undesired species, in order to deliver highly pure samples of exotic nuclei to the different set-ups which will be installed in the DESIR hall. The present manuscript describes the context and the motivations to build such a system, the targeted characteristics, and the studies to find an efficient purification method for large samples of isobaric species.

Ascher, P.; Blank, B.; Blaum, K.; Dupré, P.; Gerbaux, M.; Grévy, S.; Guérin, H.; Heck, M.; Lunney, D.; Naimi, S.; de Roubin, A.

2014-03-01

164

Temporary financial equilibrium  

Microsoft Academic Search

Summary.   In a two-period pure exchange economy with financial assets, a temporary financial equilibrium is an equilibrium of the current\\u000a spot and security markets given forecast functions of future prices and payoffs. The temporary equilibrium model can then\\u000a be interpreted as an Arrow-Debreu economy where preferences depend on prices. This identification implies, among other consequences,\\u000a the existence and the generic

Yves Balasko

2003-01-01

165

Statistical Equilibrium Dynamics  

E-print Network

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.

Michael K. -H. Kiessling

2008-05-03

166

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

SciTech Connect

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.

Raeder, Sebastian, E-mail: sebastian.raeder@fys.kuleuven.be; Ames, Friedhelm; Bishop, Daryl; Bricault, Pierre; Kunz, Peter; Mjøs, Anders [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)] [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Heggen, Henning, E-mail: heggen@triumf.ca [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada) [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Institute of Applied Physics, TU Darmstadt, Schlossgartenstr. 7, 64289 Darmstadt (Germany); Lassen, Jens, E-mail: lassen@triumf.ca; Teigelhöfer, Andrea [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada) [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)

2014-03-15

167

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

NASA Technical Reports Server (NTRS)

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.

Lambertsen, C. J.; Idicula, J.

1975-01-01

168

Discrimination of Isobaric Leu/Ile Residues by MALDI In-Source Decay Mass Spectrometry  

NASA Astrophysics Data System (ADS)

MALDI in-source decay (ISD) has been used for top-down sequencing of proteins. The use of the matrix 1,5-diaminonapthalene (1,5-DAN) gave abundant w ions, which are formed from the unimolecular dissociation of z• radical fragments via ? cleavage reaction and thus help identify which of the isobaric amino acids, Leu or Ile, is present. The high abundance of w ions in MALDI-ISD with 1,5-DAN results from the low collision rate in the MALDI plume. MALDI-ISD with 1,5-DAN appears to be an useful method for the top-down sequencing of proteins, including discrimination of Leu and Ile near the C-terminal end.

Asakawa, Daiki; Smargiasso, Nicolas; De Pauw, Edwin

2013-02-01

169

Precision test of the isobaric multiplet mass equation for the A=32, T=2 quintet  

SciTech Connect

Masses of the radionuclides {sup 32,33}Si and {sup 34}P and of the stable nuclides {sup 32}S and {sup 31}P have been measured with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. Relative mass uncertainties as low as 3x10{sup -9} have been achieved. The measured mass value of {sup 32}Si differs from the literature value by four standard deviations. The precise mass determination of {sup 32}Si and {sup 32}S have been employed to test the validity of the quadratic form of the isobaric multiplet mass equation (IMME) for the most well known A=32, T=2 isospin quintet. The new experimental results indicate a dramatic breakdown of the model.

Kwiatkowski, A. A.; Barquest, B. R.; Bollen, G.; Campbell, C. M.; Lincoln, D. L.; Morrissey, D. J.; Pang, G. K.; Prinke, A. M.; Savory, J.; Schwarz, S.; Folden, C. M. III; Melconian, D.; Sjue, S. K. L.; Block, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan (United States); Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany)

2009-11-15

170

The laser ion source trap for highest isobaric selectivity in online exotic isotope production  

SciTech Connect

The improvement in the performance of a conventional laser ion source in the laser ion source and trap (LIST) project is presented, which envisages installation of a repeller electrode and a linear Paul trap/ion guide structure. This approach promises highest isobaric purity and optimum temporal and spatial control of the radioactive ion beam produced at an online isotope separator facility. The functionality of the LIST was explored at the offline test separators of University of Mainz (UMz) and ISOLDE/CERN, using the UMz solid state laser system. Ionization efficiency and selectivity as well as time structure and transversal emittance of the produced ion beam was determined. Next step after complete characterization is the construction and installation of the radiation-hard final trap structure and its first online application.

Schwellnus, F.; Gottwald, T.; Mattolat, C.; Wendt, K. [Institut fuer Physik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Blaum, K. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Catherall, R.; Crepieux, B.; Fedosseev, V.; Marsh, B.; Rothe, S.; Stora, T. [CERN, CH-1211 Geneva 23 (Switzerland); Kluge, H.-J. [GSI, Planckstrasse 1, D-64291 Darmstadt (Germany)

2010-02-15

171

50Ti(p,p'?) Angular-Correlation Study at Isobaric Analog Resonances  

NASA Astrophysics Data System (ADS)

Angular correlations have been measured near several isobaric analog resonances observed in the 50Ti(p,p'?) reaction populating the 50Ti 2+ state at 1.555 MeV. In this manner the limitations on the J values of parent states in 51Ti were obtained. Combining the present results with the l values previously obtained from 50Ti(d,p) gives the following J? values for the indicated parent states: 2.136 MeV, 52- or 72-; 2.189 MeV, 32-; 2.896 MeV, 12-; 2.92 MeV, >=52 and 3.164 MeV, 32-. The wave function of the 2.189-MeV state of 51Ti is shown to have configurations other than the previously known p32 neutron coupled to 50Ti 2+ component.

Morgan, J. F.; Gearhart, N. L.; Hausman, H. J.; Kent, J. J.; Norton, G. A.; Sinclair, J. W.

1972-12-01

172

Preprocessing significantly improves the peptide/protein identification sensitivity of high resolution isobarically labeled tandem mass spectrometry data.  

PubMed

Isobaric labelling technique coupled with high resolution mass spectrometry has been widely employed in proteomic workflows requiring relative quantification. For each high resolution tandem mass spectrum (MS/MS), it can be used not only to quantify the peptide from different samples by reporter ions?but also to identify the peptide it derived from. Since the ions related to isobaric labeling may act as noise in database searching, the MS/MS spectrum should be preprocessed before peptide/protein identification. In this paper, we demonstrate that there are a lot of high frequency, high abundance isobaric related ions in MS/MS spectrum, and combining removing isobaric related ions with deisotoping and deconvolution in MS/MS preprocessing procedure improves the peptide/protein identification sensitivity significantly. The user-friendly software package TurboRaw2MGF (v2.0) has been implemented for converting raw TIC data files to mascot generic format files and can be downloaded for free from https://github.com/shengqh/RCPA.Tools/releases as part of the software suite ProteomicsTools. The data have been deposited to the ProteomeXchange with identifier PXD000994. PMID:25435543

Sheng, Quanhu; Li, Rongxia; Dai, Jie; Li, Qingrun; Su, Zhiduan; Guo, Yan; Li, Chen; Shyr, Yu; Zeng, Rong

2014-11-30

173

Vapor-liquid phase separator studies  

SciTech Connect

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.

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

1983-10-01

174

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

175

Getting Freshman in Equilibrium.  

ERIC Educational Resources Information Center

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…

Journal of Chemical Education, 1983

1983-01-01

176

Computing the Electricity Market Equilibrium: Uses of market equilibrium models  

E-print Network

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

Baldick, Ross

177

Chemical Principles Revisited: Chemical Equilibrium.  

ERIC Educational Resources Information Center

Describes: (1) Law of Mass Action; (2) equilibrium constant and ideal behavior; (3) general form of the equilibrium constant; (4) forward and reverse reactions; (5) factors influencing equilibrium; (6) Le Chatelier's principle; (7) effects of temperature, changing concentration, and pressure on equilibrium; and (8) catalysts and equilibrium. (JN)

Mickey, Charles D.

1980-01-01

178

Thermodynamics “beyond” local equilibrium  

PubMed Central

Nonequilibrium thermodynamics has shown its applicability in a wide variety of different situations pertaining to fields such as physics, chemistry, biology, and engineering. As successful as it is, however, its current formulation considers only systems close to equilibrium, those satisfying the so-called local equilibrium hypothesis. Here we show that diffusion processes that occur far away from equilibrium can be viewed as at local equilibrium in a space that includes all the relevant variables in addition to the spatial coordinate. In this way, nonequilibrium thermodynamics can be used and the difficulties and ambiguities associated with the lack of a thermodynamic description disappear. We analyze explicitly the inertial effects in diffusion and outline how the main ideas can be applied to other situations. PMID:11562457

Vilar, J. M. G.; Rubí, J. M.

2001-01-01

179

FRICTIONAL EQUILIBRIUM POSTURES FOR ROBOTIC  

E-print Network

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

Rimon, Elon

180

Temperature determined by isobaric yield ratios in heavy-ion collisions  

NASA Astrophysics Data System (ADS)

Background: Temperature (T) in heavy-ion collisions is an important parameter. Previously, many works have focused on the temperature of the hot emitting source. But there are few systematic studies of the temperature among heavy fragments in peripheral collisions with incident energies near the Fermi energy to a few A GeV, though it is very important to study the property of neutron-rich nucleus in heavy-ion collisions.Purpose: 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 60A MeV to 1A GeV.Methods: Isobaric yield ratio (IYR) is used to determine the temperature of heavy fragments. Cross sections of measured fragments in reactions are analyzed, and a modified statistical abrasion-ablation (SAA) model is used to calculate the yield of fragment in 140A MeV 64Ni+9Be and 1A GeV 136Xe+208Pb reactions.Results: Relatively low T of heavy fragments are obtained in different reactions (T ranges from 1 to 3 MeV). T is also found to depend on the neutron richness of the projectile. The incident energy affects T very little. ??/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 48Ca reaction, for which IYRs are A<50 isobars, is affected greatly by the temperature-corrected ?B(T). But T of reactions using IYRs of heavier fragments are only slightly affected by the temperature-corrected ?B(T). The SAA model analysis gives a consistent overview of the results extracted in this work.Conclusions: T from IYR, which is for secondary fragments, is different from that of the hot emitting source. T and ?? are essentially governed by the sequential decay process.

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

2012-11-01

181

Capillary electrophoresis-mass spectrometry determination of morphine and its isobaric glucuronide metabolites.  

PubMed

The determination of morphine and its isobaric metabolites morphine-3-beta-d-glucuronide (M3G) and morphine-6-beta-d-glucuronide (M6G) is useful for therapeutic drug monitoring and forensic identification of drug use. In particular, capillary electrophoresis with mass spectrometry (CE-MS) represents an attractive tool for opioid analysis. Whereas volatile background electrolytes in CE often improve electrospray ionization for coupled MS detection, such electrolytes may reduce CE separation efficiency and resolution. To better understand the effects of background electrolyte (BGE) composition on separation efficiency and detection sensitivity, this work compares and contrasts method development for both volatile (ammonium formate and acetate) and nonvolatile (ammonium phosphate and borate) buffers. Peak efficiencies and migration times for morphine and morphine metabolites were optimal with a 25mM ammonium borate buffer (pH=9.5) although greater sensitivities were achieved in the ammonium formate buffer. Optimized CE methods allowed for the resolution of the isobaric morphine metabolites prior to high mass accuracy, electrospray ionization quadrupole time-of-flight (ESI-QTOF) MS detection applicable to the analysis of urine samples in under seven minutes. Urine sample preparation required only a 10-fold dilution with BGE prior to analysis. Limits of detection (LOD) in normal human urine were found to be 1.0?g/mL for morphine and 2.5?g/mL for each of M3G and M6G by CE-ESI-QTOF-MS. These LODs were comparable to those for CE-UV analysis of opioid standards in buffer, whereas CE-ESI-QTOF-MS analysis of opioid standards in buffer yielded LODs an order of magnitude lower. Patient urine samples (N=12) were analyzed by this new CE-ESI-QTOF-MS method and no significant difference in total morphine content relative to prior liquid chromatography-mass spectrometry (LC-MS) results was found as per a paired-t test at the 99% confidence level. Whereas the LC-MS method applied to these samples determined only total morphine content, this new CE-ESI-QTOF-MS method allowed for species differentiation in addition to total morphine determination. By this method, it was found that M3G and M6G metabolites were present in a 5:1 concentration ratio, on average, in patient samples. Therefore, the CE-ESI-QTOF-MS method not only allows for total morphine concentration determination comparable to established LC-MS methods, but also allows for differentiation between morphine and its trace glucuronides, yielding additional biochemical information about drug metabolism. PMID:25589256

Isbell, Theresa A; Strickland, Erin C; Hitchcock, Jennifer; McIntire, Gregory; Colyer, Christa L

2015-02-01

182

Equilibrium reconstruction using ESC  

NASA Astrophysics Data System (ADS)

Free boundary equilibrium module has been supplemented to the Equilibrium and Stability Code (ESC) earlier developed for fast equilibrium calculations for transport and stability studies. At present, ESC serves as an equilibrium solver for TRANSP and ASTRA tokamak transport simulation code. The code has interfaces to several stability codes (PEST, DCON, MARS) as well as to equilibrium codes (JSOLVER, VMEQ, EFIT) mostly used for comparison of the performance. The new free boundary module includes the self-consistent calculations of the plasma shape and the external currents given the constrains on the plasma boundary and optimization conditions on the external currents. The plasma current density is controlled by the fixed-boundary module and can be specified through the parallel current density profile, q-profile, MSE-measurements, etc. Internal representation of the plasma profiles by the cubic splines, when linked with optimization procedure of reproducing probe signals, gives necessary flexibility in adjusting the plasma current density to experimental measurements. Examples of equilibrium reconstruction for NSTX and CDX-U machines are presented.

Zakharov, L. E.; Paoletti, F.; Sabbagh, S. A.

2001-10-01

183

Solving isobaric interferences in Secondary Ion Mass Spectrometry: The case of Am and Pu in irradiated thorium-based fuel  

NASA Astrophysics Data System (ADS)

Secondary Ion Mass Spectrometry (SIMS) is routinely used to provide radial isotopic distribution of actinides in irradiated nuclear fuel samples but the measurements are mainly qualitative because many isobaric interferences remain. A simple method to solve the isobaric interferences between Am and Pu for mass 241 and 242 is proposed in this work. The method is based on isotope ratio measurements currently gained by SIMS. The discussion of the results includes the evaluation of the limit of utilization of this approach as well as the enhancement possibility. The method is applied on thorium-based fuels, which represent a sustainable alternative to the classical uranium-based fuels commonly used in most of power plants around the world.

Portier, S.; Degueldre, C.; Kivel, N.

2012-07-01

184

Analysis of abscisic acid responsive proteins in Brassica napus guard cells by multiplexed isobaric tagging.  

PubMed

Guard cells, which form stomata on the leaf epidermis, play important roles in plant gas exchange and defense against pathogens. Abscisic acid (ABA) is a phytohormone that can be induced by drought and leads to stomatal closure. Guard cells have been a premier model system for studying ABA signal transduction. Despite significant progress on the identification of molecular components in the ABA signaling pathway, our knowledge of the protein components is very limited. Here, we employ a recently developed multiplexed isobaric tagging technology to identify ABA-responsive proteins in Brassica napus guard cells. A total of 431 unique proteins were identified with relative quantitative information in control and ABA-treated samples. Proteins involved in stress and defense constituted a major group among the 66 proteins with increased abundance. Thirty-eight proteins were decreased in abundance and fell into several functional groups including metabolism and protein synthesis. Many of the proteins have not been reported as being ABA responsive or involved in stomatal movement. A large percentage of the protein-coding genes contained ABA-responsive elements. This study not only established a comprehensive inventory of ABA-responsive proteins, but also identified new proteins for further investigation of their functions in guard cell ABA signaling. PMID:19913118

Zhu, Mengmeng; Simons, Brigitte; Zhu, Ning; Oppenheimer, David G; Chen, Sixue

2010-02-10

185

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

E-print Network

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.

Junlong Tian; Haitao Cui; Kuankuan Zheng; Ning Wang

2014-03-26

186

Adsorption of water vapor by poly(styrenesulfonic acid), sodium salt: isothermal and isobaric adsorption equilibria.  

PubMed

Air conditioning and dehumidifying systems based on sorption on solids are of great interest, especially in humid climates, because they allow reduction of thermal loads and use of chlorofluorocarbons. Previous studies have shown that hydrophilic polymers such as sulfonic polymers can have very high performance in water adsorption from air. The aim of this study was to characterize the water vapor adsorption properties of fully sulfonated and monosulfonated poly(styrenesulfonic acid), sodium salt, and to elucidate the mechanism of adsorption on these materials. Adsorption isotherms have been determined by TGA between 298 and 317 K for pressures ranging from 0.1 to 45 hPa. They have type II of the IUPAC classification and a small hysteresis loop between adsorption and desorption processes was observed only for the monosulfonated sample. Water content is up to 80% weight at 80% relative humidity. Adsorption isotherms have been well fitted with the FHH model. Adsorption-desorption isobars have been determined by TGA under 37 hPa in the temperature range 298-373 K. They show that these polymers can be completely regenerated by heating at 313 K under humidified air. No degradation of the adsorption properties has been observed after several regenerations. Adsorption enthalpies and entropies have been deduced from the Clapeyron equation and from DSC measurements. A good agreement was found. A mechanism of adsorption is proposed considering two kinds of adsorbate: bounded water in electrostatic interaction with functional groups and free water resulting from condensation. PMID:15533403

Toribio, F; Bellat, J P; Nguyen, P H; Dupont, M

2004-12-15

187

Excitation energies of double isobar-analog states in heavy nuclei  

SciTech Connect

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.

Poplavskii, I. V.

1988-12-01

188

Systematic comparison of label-free, metabolic labeling, and isobaric chemical labeling for quantitative proteomics on LTQ Orbitrap Velos.  

PubMed

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; and (3) iTRAQ and TMT perform similarly in all aspects compared in the current study using a CID-HCD dual scan configuration. On the basis of the unique advantages of each method, we provide guidance for selection of the appropriate method for a quantitative proteomics study. PMID:22188275

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

2012-03-01

189

Equilibrium games in networks  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

190

Step free energies at faceted solid-liquid interfaces from equilibrium molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

In this work a method is proposed for computing step free energies for faceted solid-liquid interfaces based on atomistic simulations. The method is demonstrated in an application to (111) interfaces in elemental Si, modeled with the classical Stillinger-Weber potential. The approach makes use of an adiabatic trapping procedure, and involves simulations of systems with coexisting solid and liquid phases separated by faceted interfaces containing islands with different sizes, for which the corresponding equilibrium temperatures are computed. We demonstrate that the calculated coexistence temperature is strongly affected by the geometry of the interface. We find that island radius is inversely proportional to superheating, allowing us to compute the step free energy by fitting simulation data within the formalism of classical nucleation theory. The step free energy value is computed to be ?st = 0.103 ± 0.005 × 10-10 J/m. The approach outlined in this work paves the way to the calculation of step free energies relevant to the solidification of faceted crystals from liquid mixtures, as encountered in nanowire growth by the vapor-liquid-solid mechanism and in alloy casting. The present work also shows that at low undercoolings the Stillinger-Weber interatomic potential for Si tends to crystallize in the wurtzite, rather than the diamond-cubic structure.

Frolov, T.; Asta, M.

2012-12-01

191

Equation of state and liquid-vapor equilibrium of polarizable Stockmayer fluids  

NASA Astrophysics Data System (ADS)

In this work we develop the concept of an effective potential to obtain the equation of state of polarizable Stockmayer (PSM) fluids. This potential consists of a Lennard-Jones function with appropriate energy and distance parameters that depend on the reduced dipolar moment ? ^ast and polarizability ? ^ast. The approach deals accurately with polarizable SM fluids with ? ^{ast } ? 2.0 and ? ^{ast } ? 0.1. However, prediction of second virial coefficients is reliable up to ? ^{ast } ? 4.0. When the low-density sphericalized potential is used at moderate and large densities, the effect of the dipole-dipole attraction is overestimated in agreement with an effect previously found in the literature. This effect can be traced back to a frustration mechanism due to the interaction between three and more dipoles. We propose a model to account for this frustration effect and are able to reproduce the vapor-liquid equilibrium of polarizable SM fluids in agreement with simulated results from the literature. Molecular dynamics simulations were carried out to show that the effective SM fluid has a radial distribution function very close to that of the true SM system.

Rocha-Ichante, Adrián; del Río, Fernando; Ávalos, Edgar

2010-12-01

192

Local Stellarator Equilibrium Model  

NASA Astrophysics Data System (ADS)

Extensive calculations of ballooning and drift waves spectrums in asymmetric toroidal configurations (e.g. stellarators) to appreciate the role of magnetic geometry and profile variations are usually are usually prohibitive as the evaluation of the magneto-hydrodynamic (MHD) equilibrium is in itself a non-trivial problem. Although simple analytical MHD model equilibria do exist for tokamak configurations, their stellarator counterparts are usually crude or very approximate. In order to make more extensive stability calculations (of both ideal ballooning and drift-type modes), a technique for generating three-dimensional magneto-static equilibria, localized to a magnetic surface, has been developed. The technique allows one to easily manipulate various 3-D shaping and profile effects on a magnetic surface avoiding the need to recompute an entire three dimensional solution of the equilibrium. The model equilibrium has been implemented into existing ideal MHD ballooning and drift wave numerical codes. Marginal ballooning stability diagrams and drift wave calculations will be reported.

Hudson, Stuart R.; Hegna, Chris C.; Lewandowski, Jerome W.

2000-10-01

193

ON BERGE EQUILIBRIUM Rabia Nessah  

E-print Network

ON BERGE EQUILIBRIUM Rabia Nessah CNRS-LEM (UMR 8179), IESEG School of Management, 3 rue de la Abstract Based on the notion of equilibrium of a coalition P relatively to a coalition K, of Berge, Zhukovskii has introduced Berge equilibrium as an alternative solution to Nash equilibrium for non

Paris-Sud XI, Université de

194

An Updated Equilibrium Machine  

ERIC Educational Resources Information Center

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…

Schultz, Emeric

2008-01-01

195

Deviation from secular equilibrium  

E-print Network

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.

A. V. Simakin; G. A. Shafeev

2010-01-20

196

On quantum microcanonical equilibrium  

E-print Network

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.

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

2006-12-14

197

Measurement and correlation of vapor–liquid equilibria of binary systems containing the ionic liquids [EMIM][(CF 3SO 2) 2N], [BMIM][(CF 3SO 2) 2N], [MMIM][(CH 3) 2PO 4] and oxygenated organic compounds respectively water  

Microsoft Academic Search

Vapor–liquid equilibria (VLE) have been measured for methanol, ethanol, 2-propanol, acetone, tetrahydrofuran (THF) and water with the ionic liquids 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [EMIM][(CF3SO2)2N], 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [BMIM][(CF3SO2)2N], 1-methyl-3-methyl-imidazolium dimethylphosphate [MMIM][(CH3)2PO4] at 353.15K with the help of a computer-driven static apparatus.For water a miscibility gap was observed with [EMIM][(CF3SO2)2N] and [BMIM][(CF3SO2)2N] at 353.15K, for the oxygenated compounds (acetone, alcohols and THF) homogeneous behavior

Ryo Kato; Jürgen Gmehling

2005-01-01

198

An Updated Equilibrium Machine  

NASA Astrophysics Data System (ADS)

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.

Schultz, Emeric

2008-08-01

199

Covariant Equilibrium Statistical Mechanics  

E-print Network

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.

E. Lehmann

2006-02-25

200

Equilibrium shape of Si  

Microsoft Academic Search

Small voids are formed in Si by MeV He implantation and annealing. We measure the equilibrium shape of these voids and hence extract the surface energy curve gamma(theta) for Si. gamma(111) is the global minimum, with gamma(100)~=1.1gamma(111) and all other cusps on the surface being relatively small. The experimental gamma(theta) is compared with theoretical predictions and earlier experiments. Step energies

D. J. Eaglesham; A. E. White; L. C. Feldman; N. Moriya; D. C. Jacobson

1993-01-01

201

Gravity, Dimension, Equilibrium, & Thermodynamics  

E-print Network

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.

Jerome Perez

2006-03-30

202

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

USGS Publications Warehouse

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. -Authors

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

1989-01-01

203

Introduction to Carbonate Equilibrium  

NSDL National Science Digital Library

The activity asks students to make observations about what occurs when two effervescent antacid tablets are placed into a beaker of water. The Students work together in groups. There are three parts to the activity. In the first part, the tablets are dropped into tap water and student groups (2-4 students) must complete a series of question sheets (one per group) that guide them through thinking about the event. In the second part, a presentation on chemical equilibrium for the carbonate system is given. The starting point is the answers received in the first part. Basic chemical reactions for the carbonate system are presented including equilibrium expressions for each reaction and discussion about open and closed systems. At the end of class, a handout is given to the students. In the third part, three beakers (acidic, neutral and basic solutions, but not indicated) are placed together and two tablets are placed into each beaker. Students are split into two groups (8-12 students) and are asked to describe why the reactions are different. Discussion follows collection of student responses in each part. Once the chemical reactions and equilibrium expressions are presented, they are involved and referenced in all discussions.

michael stapleton

204

Energy Flows in a Quasi-Isobaric Fusion-Fission Hybrid Reactor  

NASA Astrophysics Data System (ADS)

We have examined the dominant mechanisms of energy flow in a fusion-fission hybrid reactor, which is based on a magnetically confined thermonuclear D-T plasma. D -T fusion provides a source of high-energy neutrons which are absorbed in a blanket outside the reactor. The blanket combines the functions of energy multiplication by fission of U^{238}, Pu ^{239} and U^{233 }, and tritium breeding. The fusion "driver" produces 100 MW of neutron power while the blanket provides energy multiplication of about 50. The hybrid can produce about 2000 MW of electrical power. The plasma is contained in the space between two concentric cylinders. There is uniformity in the direction parallel to the curved surfaces of the cylinders, and the confining field is purely toroidal. The plasma has a rectangular cross-section bounded by a planar electrode at one end and a thermionic emitter at the other, and cylindrical walls inside and outside. There is a modest pressure gradient, i.e., nT ~ constant. The temperature is high in the core of the plasma, where fusion occurs, but falls to low values near the walls and end-plates. It is hoped that the quasi-isobaric character will eliminate serious instabilities, and that plasma behaviour will be near-classical. The high-n, low-T periphery should reduce damage to the walls from energetic plasma particles. We have found a class of sustainable MHD equilibria with Q ~ 0.3. The inner and outer radii and height of the reactor are 31, 38 and 7 metres respectively. A high magnetic field is required, in the range 200-400 kG. T rises from 200 eV at the walls to 2.7 keV in the fusion zone, where n_ {rm e}~ 1.5 times 10^{14} cm^{-3}. There is a small vertical flow velocity to provide fueling. We have studied alpha-particle slowing down, electron-cyclotron radiation transport, inelastic reactions, bremsstrahlung, conduction, convection, and heat exchange between electrons and ions in the reactor. RF heating in the lower hybrid range can balance the differential energy equations for electrons and ions throughout the reactor.

Chaturvedi, Shashank

205

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

SciTech Connect

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.

Aygor, H. Ali; Maras, Ismail [Celal Bayar University, Department of Physics, Manisa (Turkey); Cakmak, Necla; Selam, Cevad [Anadolu University, Department of Physics, Eskisehir (Turkey)

2008-11-11

206

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

SciTech Connect

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.

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

207

ChemTeacher: Equilibrium Constant  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Equilibrium Constant page includes resources for teaching students about defining and using equilibrium constants.

2012-07-24

208

NON-EQUILIBRIUM THERMODYNAMIC PROCESSES: SPACE PLASMAS AND THE INNER HELIOSHEATH  

SciTech Connect

Recently, empirical kappa distribution, commonly used to describe non-equilibrium systems like space plasmas, has been connected with non-extensive statistical mechanics. Here we show how a consistent definition of the temperature and pressure is developed for stationary states out of thermal equilibrium, so that the familiar ideal gas state equation still holds. In addition to the classical triplet of temperature, pressure, and density, this generalization requires the kappa index as a fourth independent thermodynamic variable that characterizes the non-equilibrium stationary states. All four of these thermodynamic variables have key roles in describing the governing thermodynamical processes and transitions in space plasmas. We introduce a novel characterization of isothermal and isobaric processes that describe a system's transition into different stationary states by varying the kappa index. In addition, we show how the variation of temperature or/and pressure can occur through an 'iso-q' process, in which the system remains in a fixed stationary state (fixed kappa index). These processes have been detected in the proton plasma in the inner heliosheath via specialized data analysis of energetic neutral atom (ENA) observations from Interstellar Boundary Explorer. In particular, we find that the temperature is highly correlated with (1) kappa, asymptotically related to isothermal ({approx}1,000,000 K) and iso-q ({kappa} {approx} 1.7) processes; and (2) density, related to an isobaric process, which separates the 'Ribbon', P Almost-Equal-To 3.2 pdyn cm{sup -2}, from the globally distributed ENA flux, P Almost-Equal-To 2 pdyn cm{sup -2}.

Livadiotis, G.; McComas, D. J., E-mail: glivadiotis@swri.edu [Southwest Research Institute, San Antonio, TX (United States)

2012-04-10

209

Structural design using equilibrium programming  

NASA Technical Reports Server (NTRS)

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.

Scotti, Stephen J.

1992-01-01

210

Lecture Ch. 4a Equilibrium  

E-print Network

Tv = T 1+ 0.608qv( ) = T p0 p # $ % & ' ( Rd cpd Water Vapor Metrics Temperature Metrics · Virtual.5.1), 4.6) Reminder: Homework Problem Ch.4 Prob. 4, 5 Take-home point: Water is very unique, as is its. #12;2 Pure water (1 component) Phase Equilibrium · Thermal equilibrium · Mechanical equilibrium

Russell, Lynn

211

Grinding kinetics and equilibrium states  

Microsoft Academic Search

The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution

L. Opoczky; F. Farnady

1984-01-01

212

Evolutionary Drift and Equilibrium Selection  

Microsoft Academic Search

This paper develops an approach to equilibrium selection in game theory based on studying the learning process through which equilibrium is achieved. The differential equations derived from models of interactive learning typically have stationary states that are not isolated. Instead, Nash equilibria that specify different out-of- equilibrium behavior appear in connected components of stationary states. The stability properties of these

Larry Samuelson

1997-01-01

213

LABORATORY I FORCES AND EQUILIBRIUM  

E-print Network

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

Minnesota, University of

214

3D Equilibrium Reconstruction for  

E-print Network

3D Equilibrium Reconstruction for Stellarators and Tokamaks Samuel A. Lazerson1 D. Gates1, N;Accurate modeling of experimental conditions requires 3D equilibrium reconstruction · Three-dimensional equilibrium effects are significant for both stellarators and tokamaks · Internal Helical States · RMP

Columbia University

215

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

E-print Network

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

Cross, Michael

216

On the gyrokinetic equilibrium  

SciTech Connect

Recent developments in gyrokinetic-magnetohydrodynamics (MHD) theory and in electromagnetic gyrokinetic particle simulations raise the question of consistency between the gyrokinetic model and the fluid model. Due to the special characteristics of the guiding center coordinates, it is a nontrivial exercise to show this consistency. In this paper it is shown, in a very general setting, that the gyrokinetic theory and the fluid equations do give an equivalent description of plasma equilibrium ({partial_derivative}/(partial deriv)t=0). The fluid continuity equation and momentum equation for equilibrium plasmas are recovered entirely from the gyrokinetic theory. However, it was Spitzer who first realized the importance of consistency between guiding-center motion and fluid equations. In particular, he studied the ''apparent paradoxical result'' regarding the difference between perpendicular particle flow and guiding-center flow, which will be referred to as the Spitzer paradox in this paper. By recovering the fluid equations from the gyrokinetic theory, we automatically resolve the Spitzer paradox, whose essence is how the perpendicular current and flow are microscopically generated from particles' guiding-center motion. The mathematical construction in the gyrokinetic theory which relates observable quantities in the laboratory frame to the distribution function in the guiding-center coordinates is consistent with Spitzer's original physical picture, while today's gyrokinetic-MHD theory covers a much wider range of problems in a much more general and quantitative way. (c) 2000 American Institute of Physics.

Qin, H. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Tang, W. M. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Rewoldt, G. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Lee, W. W. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

2000-03-01

217

Weak Acid Equilibrium  

NSDL National Science Digital Library

Students are asked to calculate the pH of a weak acid aqueous solution. The problems involve a series of generic acids with assigned equilibrium constants (Ka) and total concentrations (Ct). Initially, students are required to hand calculate all problems by algebraic manipulation of the mathematical relationships of the system. The solution is a cubic equation. Through a series of assumptions, the solution is simplified. The assumptions are based on the chemistry of the system given the Ka and Ct for the problem. The problems are then graphically solved. Ultimately, the students develop an Excel worksheet to solve the problems and a Bjerrum plot to display the speciation as a function of pH.

Stapleton, Michael

218

Statistical physics ""Beyond equilibrium  

SciTech Connect

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.

Ecke, Robert E [Los Alamos National Laboratory

2009-01-01

219

Determine equilibrium absorption rates  

SciTech Connect

Process engineers can predict quickly and accurately the equilibrium behavior of simultaneous H/sub 2/S and CO/sub 2/ absorptions in monoethanolamine and diethanolamine systems by using the nomographs developed by H.K. Ferguson Co. Correlation lines for temperature and amine concentration provided with the loading curves make the nomographs useful for any combination of temperature, concentration, and liquid loadings. The accuracy of the nomographs is within the acceptable range for normal engineering applications when the operating parameters lie in the region of practical gas-treating conditions. Correction curves given for each nomograph to improve the accuracy are generally not needed except for cases where the gas loadings are higher than 0.5 mole/mole of amine.

Chen, C.C.; Ng, A.

1980-04-01

220

Grinding kinetics and equilibrium states  

NASA Technical Reports Server (NTRS)

The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.

Opoczky, L.; Farnady, F.

1984-01-01

221

Phase equilibrium data for development of correlations for coal fluids  

SciTech Connect

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.

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

1991-02-01

222

General Equilibrium Simulation for Microeconomics  

NSDL National Science Digital Library

Teaching general equilibrium analysis to students is challenging. General equilibrium models are typically accessible to only a small handful of mathematically well prepared students. Yet the growing significance of general equilibrium models in economics challenges instructors to find ways to make these models accessible to undergraduate students. The simulation gives microeconomics instructors an alternative to the traditional Edgeworth box graphical presentation. The simulation, with sample parameter files, is implemented with a Java applet available at General Equilibrium Simulations. The developers of the simulation are Walter Nicholson and Frank Westhoff at Amherst College.

Blecha, Betty

223

The feasibility of isobaric suppression of 26Mg via post-accelerator foil stripping for the measurement of 26Al  

NASA Astrophysics Data System (ADS)

Most accelerator mass spectrometry measurements of 26Al utilize the Al- ion despite lower source currents compared with AlO- since the stable isobar 26Mg does not form elemental negative ions. A gas-filled magnet allows sufficient suppression of 26Mg thus enabling the use of the more intense 26AlO- ion. However, most AMS systems do not include a gas-filled magnet. We therefore explored the feasibility of suppressing 26Mg by using a post-accelerator stripping foil. With this approach, combined with the use of alternative cathode matrices, we were able to suppress 26Mg by a factor of 20. This suppression was insufficient to enable the use of 26AlO-, however further refinement of our system may permit its use in the future.

Tumey, Scott J.; Brown, Thomas A.; Finkel, Robert C.; Rood, Dylan H.

2013-01-01

224

Study of the linear ablation growth rate for the quasi isobaric model of Euler equations with thermal conductivity  

E-print Network

In this paper, we study a linear system related to the 2d system of Euler equations with thermal conduction in the quasi-isobaric approximation of Kull-Anisimov [14]. This model is used for the study of the ablation front instability, which appears in the problem of inertial confinement fusion. This physical system contains a mixing region, in which the density of the gaz varies quickly, and one denotes by L0 an associated characteristic length. The system of equations is linearized around a stationary solution, and each perturbed quantity is written using the normal modes method. The resulting linear system is not self-adjoint, of order 5, with coefficients depending on x and on physical parameters $\\alpha, \\beta$. We calculate Evans function associated with this linear system, using rigorous constructions of decreasing at $\\pm \\infty$ solutions of systems of ODE. We prove that for $\\alpha$ small, there is no bounded solution of the linearized system.

Lafitte, Olivier

2007-01-01

225

Drop tower experiment for performance evaluation of gas-liquid equilibrium thruster for small spacecraft  

NASA Astrophysics Data System (ADS)

JAXA/ISAS is developing the gas-liquid equilibrium thruster for a small spacecraft. In small spacecrafts, the thruster system must be simple and its weight must be light. This thruster system uses HFC-134a (1,1,1,2-tetrafluoroethane) , a kind of liquefied gas, as propellant because of its harmlessness and ease of handling. And this thruster stores propellant as liquid in the tank and ejects propellant as gas using the gas-liquid equilibrium pressure to produce thrust, so the propellant tank only needs to resist the vapor pressure of propellant. In this thruster system, the porous metal is also equipped in the tank for the following performance advantages: (1) liquid fuel retention: The porous metal reduces sloshing problems which cause bad effects on spacecraft attitude by retaining liquid propellant inside the porous metal: (2) vapor-liquid separation: The porous metal also helps propellant separate gas from liquid by advancing propellant vaporization on its large surface area and retaining liquid propellant using its surface tension. In last autumn, we carried out the experiment to evaluate these two advantages of porous metal under micro gravity condition using 50 meters drop tower in Hokkaido, Japan. The system of this experiment divides into two different systems. The first one evaluates liquid propellant retention performance by adding disturbance to liquid propellant absorbed in porous metal. The disturbance is centrifugal force and angular acceleration worked on the liquid propellant by rotating propellant tank controlled by motor. A high speed camera records the behavior of the liquid propellant. The other one evaluates the ability of gas-liquid separation on the case of propellant ejection. In this evaluation, the parameters are full filling porous metal or some ullage in the tank, nozzle diameters and the filling ratio of liquid propellant in the tank. As for (1) liquid fuel retention, in all conducted cases without propellant ejection, liquid propellant was retained in the porous metal. It is obvious that the porous metal is effective for decreasing of sloshing problems. We evaluated this effectiveness analytically based on head pressure worked on liquid propellant as centrifugal force and angular acceleration. As for (2)vapor-liquid separation, liquid propellant retained inside the porous metal started to boil right after propellant ejection occurred and propellant was ejected mixed with liquid. And after propellant ejection, it takes some time to recover tank pressure into saturated vapor pressure. To obtain stable thrust force, it is required to halt the propellant ejection just before the tank pressure reaches to the break point pressure and to take enough ejection intervals to recover the tank pressure. From these experiments, for practical use of this thruster system, that is, to avoid liquid propellant ejection, it is important to ensure adequate ullage volume of tank to achieve mission requirement.

Motooka, Norizumi; Yamamoto, Takayuki; Mori, Osamu; Okano, Yoshinobu; Kishino, Yoshihiro; Kawaguchi, Junichiro

226

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

SciTech Connect

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.

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

227

Molecular dynamics in the isothermal-isobaric ensemble: the requirement of a "shell" molecule. III. Discontinuous potentials.  

PubMed

Based on the approach of Gruhn and Monson [Phys. Rev. E 63, 061106 (2001)], we present a new method for deriving the collisions dynamics for particles that interact via discontinuous potentials. By invoking the conservation of the extended Hamiltonian, we generate molecular dynamics (MD) algorithms for simulating the hard-sphere and square-well fluids within the isothermal-isobaric (NpT) ensemble. Consistent with the recent rigorous reformulation of the NpT ensemble partition function, the equations of motion impose a constant external pressure via the introduction of a shell particle of known mass [M. J. Uline and D. S. Corti, J. Chem. Phys. 123, 164101 (2005); 123, 164102 (2005)], which serves to define uniquely the volume of the system. The particles are also connected to a temperature reservoir through the use of a chain of Nose-Hoover thermostats, the properties of which are not affected by a hard-sphere or square-well collision. By using the Liouville operator formalism and the Trotter expansion theorem to integrate the equations of motion, the update of the thermostat variables can be decoupled from the update of the positions of the particles and the momentum changes upon a collision. Hence, once the appropriate collision dynamics for the isobaric-isenthalpic (NpH) equations of motion is known, the adaptation of the algorithm to the NpT ensemble is straightforward. Results of MD simulations for the pure component square-well fluid are presented and serve to validate our algorithm. Finally, since the mass of the shell particle is known, the system itself, and not a piston of arbitrary mass, controls the time scales for internal pressure and volume fluctuations. We therefore consider the influence of the shell particle algorithm on the dynamics of the square-well fluid. PMID:18624470

Uline, Mark J; Corti, David S

2008-07-01

228

Kinetic equilibrium and relativistic thermodynamics  

E-print Network

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.

P. Ván

2011-02-01

229

Rapid-Equilibrium Enzyme Kinetics  

ERIC Educational Resources Information Center

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…

Alberty, Robert A.

2008-01-01

230

STP Approach To Equilibrium Program  

NSDL National Science Digital Library

The ApproachToEquilibrium program displays the number of particles on one half of a box as a function of time after a small hole is made in the partition dividing the box in half. The purpose of this simulation is to gain insight into the tendency of macroscopic systems to approach a well defined equilibrium macrostate and the improtance of fluctuations in equilibrium. ApproachToEquilibrium is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready- to-run (compiled) Java archive. Double-clicking the stp ApproachToEquilibrium.jar file will run the program if Java is installed on your computer. Additional Open Source Physics programs for Statistical and Thermal Physics can be found by searching ComPADRE for Open Source Physics, STP or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2008-10-10

231

Non-equilibrium chemistry and cooling in the diffuse interstellar medium - I. Optically thin regime  

NASA Astrophysics Data System (ADS)

An accurate treatment of the multiphase interstellar medium (ISM) in hydrodynamic galaxy simulations requires that we follow not only the thermal evolution of the gas, but also the evolution of its chemical state, including its molecular chemistry, without assuming chemical (including ionization) equilibrium. We present a reaction network that can be used to solve for this thermo-chemical evolution. Our model follows the evolution of all ionization states of the 11 elements that dominate the cooling rate, along with important molecules such as H2 and CO, and the intermediate molecular species that are involved in their formation (20 molecules in total). We include chemical reactions on dust grains, thermal processes involving dust, cosmic ray ionization and heating and photochemical reactions. We focus on conditions typical for the diffuse ISM, with densities of 10-2 cm-3? nH?104 cm-3 and temperatures of 102 K ? T ? 104 K, and we consider a range of radiation fields, including no UV radiation. In this paper, we consider only gas that is optically thin, while paper II considers gas that becomes shielded from the radiation field. We verify the accuracy of our model by comparing chemical abundances and cooling functions in chemical equilibrium with the photoionization code CLOUDY. We identify the major coolants in diffuse interstellar gas to be C II, Si II and Fe II, along with O I and H2 at densities nH ? 102 cm-3. Finally, we investigate the impact of non-equilibrium chemistry on the cooling functions of isochorically or isobarically cooling gas. We find that, at T < 104 K, recombination lags increase the electron abundance above its equilibrium value at a given temperature, which can enhance the cooling rate by up to two orders of magnitude. The cooling gas also shows lower H2 abundances than in equilibrium, by up to an order of magnitude.

Richings, A. J.; Schaye, J.; Oppenheimer, B. D.

2014-06-01

232

Colloidal Gels: Equilibrium and Non-Equilibrium Routes  

E-print Network

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.

Emanuela Zaccarelli

2007-06-12

233

Helical axis stellarator equilibrium model  

SciTech Connect

An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift.

Koniges, A.E.; Johnson, J.L.

1985-02-01

234

Determination of vapor liquid equilibrium for the ternary iso-propanol/atactic-polypropylene/n-heptane mixture at 105C and 140C, and the binary iso-propanol/atactic-polypropylene mixture at 85C using perturbation gas chromatography / cby Lamar Lane Joffrion  

E-print Network

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Joffrion, Lamar Lane

1984-01-01

235

Essays in dynamic general equilibrium  

E-print Network

This thesis consists of three chapters studying dynamic economies in general equilibrium. The first chapter considers an economy in business cycles with potentially imperfect financial markets. The second chapter investigates ...

Cao, Dân (Dân Vu?)

2010-01-01

236

Equilibrium Electro-osmotic Instability  

E-print Network

Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. 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 numerical 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 in the solid) allows for equilibrium electro-osmotic instability. Moreover, we s...

Rubinstein, Isaak

2014-01-01

237

Equilibrium ignition for ICF capsules  

SciTech Connect

There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter. Equilibrium or volume ignition sacrifices high gain for lower losses, lower ignition temperature, lower implosion velocity and lower sensitivity of the more robust capsule to small fluctuations and asymmetries in the drive system. The reduction in gain is about a factor of 2.5, which is small enough to make the more robust equilibrium ignition an attractive alternative.

Lackner, K.S.; Colgate, S.A.; Johnson, N.L.; Kirkpatrick, R.C.; Menikoff, R.; Petschek, A.G.

1993-12-31

238

Equilibrium Selection via Travelling Waves Josef Hofbauer  

E-print Network

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

Hofbauer, Josef

239

AUCTION EQUILIBRIUM WITH COSTLY INFORMATION ACQUISITION  

E-print Network

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

Kolstad, Charles

240

Equilibrium forms of protein crystals  

NASA Astrophysics Data System (ADS)

Models for equilibrium forms of protein crystals were suggested using classical methods, such as Stranski-Kaischew's mean-separation-work method and the Gibbs-Curie-Wulff law. Although absolute bonding energies in protein crystal lattices are unknown, their relative strength was estimated from the type of lattice contacts observed in the protein x-ray structures. Equilibrium forms of ferritin crystals deduced on this basis were compared with experimental observations of Yau and Vekilov.

Nanev, Christo N.

2012-12-01

241

A search for equilibrium states  

NASA Technical Reports Server (NTRS)

An efficient search algorithm is described for the location of equilibrium states in a search set of states which differ from one another only by the choice of pure phases. The algorithm has three important characteristics: (1) it ignores states which have little prospect for being an improved approximation to the true equilibrium state; (2) it avoids states which lead to singular iteration equations; (3) it furnishes a search history which can provide clues to alternative search paths.

Zeleznik, F. J.

1982-01-01

242

Edge equilibrium code for tokamaks  

SciTech Connect

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.

Li, Xujing [Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, P.O. Box 2719, Beijing 100190 (China)] [Institute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, P.O. Box 2719, Beijing 100190 (China); Zakharov, Leonid E. [Princeton Plasma Physics Laboratory Princeton, MS-27 P.O. Box 451, New Jersey (United States)] [Princeton Plasma Physics Laboratory Princeton, MS-27 P.O. Box 451, New Jersey (United States); Drozdov, Vladimir V. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)] [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2014-01-15

243

Equilibrium Electro-osmotic Instability  

E-print Network

Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. 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 numerical 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 in the solid) allows for equilibrium electro-osmotic instability. Moreover, we suggest a simple experimental test for determining the true, either equilibrium or non-equilibrium, origin of electro-osmotic instability.

Isaak Rubinstein; Boris Zaltzman

2014-03-18

244

Canonical dynamics: Equilibrium phase-space distributions  

Microsoft Academic Search

Nose has modified Newtonian dynamics so as to reproduce both the canonical and the isothermal-isobaric probability densities in the phase space of an N-body system. He did this by scaling time (with s) and distance (with V¹D\\/ in D dimensions) through Lagrangian equations of motion. The dynamical equations describe the evolution of these two scaling variables and their two conjugate

William Hoover

1985-01-01

245

Quantum Statistical Mechanics. III. Equilibrium Probability  

E-print Network

Given are a first principles derivation and formulation of the probabilistic concepts that underly equilibrium quantum statistical mechanics. The transition to non-equilibrium probability is traversed briefly.

Phil Attard

2014-04-10

246

Shape characteristics of equilibrium and non-equilibrium fractal clusters.  

PubMed

It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other between the viscosity and hydrodynamic radii, as potential measures of shape anisotropy. We also find a strong correlation between anisotropy and effective fractal dimension. These observations should provide new practical methods for quantifying the nature of particle clustering in diverse contexts. PMID:23902013

Mansfield, Marc L; Douglas, Jack F

2013-07-28

247

Shape characteristics of equilibrium and non-equilibrium fractal clusters  

NASA Astrophysics Data System (ADS)

It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other between the viscosity and hydrodynamic radii, as potential measures of shape anisotropy. We also find a strong correlation between anisotropy and effective fractal dimension. These observations should provide new practical methods for quantifying the nature of particle clustering in diverse contexts.

Mansfield, Marc L.; Douglas, Jack F.

2013-07-01

248

Identification of Novel Escherichia coli Ribosome-Associated Proteins Using Isobaric Tags and Multidimensional Protein Identification Techniques? †  

PubMed Central

Biogenesis of the large ribosomal subunit requires the coordinate assembly of two rRNAs and 33 ribosomal proteins. In vivo, additional ribosome assembly factors, such as helicases, GTPases, pseudouridine synthetases, and methyltransferases, are also critical for ribosome assembly. To identify novel ribosome-associated proteins, we used a proteomic approach (isotope tagging for relative and absolute quantitation) that allows for semiquantitation of proteins from complex protein mixtures. Ribosomal subunits were separated by sucrose density centrifugation, and the relevant fractions were pooled and analyzed. The utility and reproducibility of the technique were validated via a double duplex labeling method. Next, we examined proteins from 30S, 50S, and translating ribosomes isolated at both 16°C and 37°C. We show that the use of isobaric tags to quantify proteins from these particles is an excellent predictor of the particles with which the proteins associate. Moreover, in addition to bona fide ribosomal proteins, additional proteins that comigrated with different ribosomal particles were detected, including both known ribosomal assembly factors and unknown proteins. The ribosome association of several of these proteins, as well as others predicted to be associated with ribosomes, was verified by immunoblotting. Curiously, deletion mutants for the majority of these ribosome-associated proteins had little effect on cell growth or on the polyribosome profiles. PMID:17337586

Jiang, M.; Sullivan, S. M.; Walker, A. K.; Strahler, J. R.; Andrews, P. C.; Maddock, J. R.

2007-01-01

249

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

250

Charge-exchange scattering to the isobaric analog state at medium energies as a probe of the neutron skin  

NASA Astrophysics Data System (ADS)

The charge-exchange (He3,t) scattering to the isobaric analog state (IAS) of the target can be considered as "elastic" scattering of He3 by the isovector term of the optical potential (OP) that flips the projectile isospin. Therefore, the accurately measured charge-exchange scattering cross section for the IAS can be a good probe of the isospin dependence of the OP, which is determined exclusively within the folding model by the difference between the neutron and proton densities and isospin dependence of the nucleon-nucleon interaction. Given the neutron skin of the target related directly to the same density difference, it can be well probed in the analysis of the charge-exchange (He3,t) reactions at medium energies when the two-step processes can be neglected and the t-matrix interaction can be used in the folding calculation. For this purpose, the data of the (He3,t) scattering to the IAS of Zr90 and Pb208 targets at Elab=420 MeV have been analyzed in the distorted wave Born approximation using the double-folded charge-exchange form factor. The neutron skin deduced for these two nuclei turned out to be in a good agreement with the existing database.

Loc, Bui Minh; Khoa, Dao T.; Zegers, R. G. T.

2014-02-01

251

Charge-exchange scattering to the isobaric analog state at medium energies as a probe of the neutron skin  

E-print Network

The charge-exchange (3He,t) scattering to the isobaric analog state (IAS) of the target can be considered as "elastic" scattering of 3He by the isovector term of the optical potential (OP) that flips the projectile isospin. Therefore, the accurately measured charge-exchange scattering cross- section for the IAS can be a good probe of the isospin dependence of the OP, which is determined exclusively within the folding model by the difference between the neutron and proton densities and isospin dependence of the nucleon-nucleon interaction. Given the neutron skin of the target is related directly to the same density difference, it can be well probed in the analysis of the charge- exchange (3He,t) reactions at medium energies when the two-step processes can be neglected and the t-matrix interaction can be used in the folding calculation. For this purpose, the data of the (3He,t) scattering to the IAS of 90Zr and 208Pb targets at Elab = 420 MeV have been analyzed in the distorted wave Born approximation using the...

Loc, Bui Minh; Zegers, R G T

2014-01-01

252

Critical and phase-equilibrium properties of an ab initio based potential model of methanol and 1-propanol using two-phase molecular dynamics simulations.  

PubMed

Two-phase molecular dynamics simulations employing a Monte Carlo volume sampling method were performed using an ab initio based force field model parameterized to reproduce quantum-mechanical dimer energies for methanol and 1-propanol at temperatures approaching the critical temperature. The intermolecular potential models were used to obtain the binodal vapor-liquid phase dome at temperatures to within about 10 K of the critical temperature. The efficacy of two all-atom, site-site pair potential models, developed solely from the energy landscape obtained from high-level ab initio pair interactions, was tested for the first time. The first model was regressed from the ab initio landscape without point charges using a modified Morse potential to model the complete interactions; the second model included point charges to separate Coulombic and dispersion interactions. Both models produced equivalent phase domes and critical loci. The model results for the critical temperature, density, and pressure, in addition to the sub-critical equilibrium vapor and liquid densities and vapor pressures, are compared to experimental data. The model's critical temperature for methanol is 77 K too high while that for 1-propanol is 80 K too low, but the critical densities are in good agreement. These differences are likely attributable to the lack of multi-body interactions in the true pair potential models used here. PMID:22191893

Patel, Sonal; Wilding, W Vincent; Rowley, Richard L

2011-12-21

253

Temperature effect on solid-supercritical fluid phase equilibrium and its molecular basis  

SciTech Connect

Temperature effects on solid-supercritical phase equilibrium and its molecular basis is researched in this paper based on the experimental isobaric solubility data of CO{sub 2}/Naphthalene binary system with pressure ranging from 8.0 MPa to 10.0 MPa and temperature range from 308 K to 333 K. The data are measured with a micro SFE-SFC equipment set up by the authors. The primary factor responsible for the strength of temperature influence on solid solubility in the retrograde region is shown to be solute partial molar excess enthalpy. This property is calculated by both PR-EOS and the Gibbs-Konowalow rule for solid/fluid phase equilibrium. The interaction parameters of PR-EOS are optimized using by using experimental data and numerical partial differentiation of solubility data with respect to temperature at constant pressure used in Gibbs-Konowalow rule. Two methods are in good agreement. It is found that solute excess partial molar enthalpy diverge negatively in retrograde region of the system and the temperature effect is profound. A basic formula has been derived correlating the excess partial molar enthalpy with cluster size defined by Kirkwood-Buff solution theory, by which the strong exothermicity can be explained. Solute excess partial molar enthalpy is proved to be proportional to cluster size of the solvent molecules around a solute molecule. Theory and calculation results show that for attractive system stronger negative divergence of solute excess partial molar enthalpy corresponds to larger cluster size.

Suoqi, Z.; Guanghua, Y. [Univ. of Petroleum, Beijing (China)

1996-10-01

254

Equilibrium states of gravitational systems  

NASA Astrophysics Data System (ADS)

We formulate the equilibrium correlation functions for local observables of an assembly of non-relativistic, neutral gravitating fermions in the limit where the number of particles becomes infinite, and in a scaling where the region ?, to which they are confined, remains fixed. We show that these correlation functions correspond, in the limit concerned, to states on the discrete tensor productmathop ? limits_{x in ? } A_x , where theA_x 's are copies of the gauge invariant C*-algebraA of the CAR over L 2( R 3). The equilibrium states themselves are then given bymathop ? limits_{x in ? } bar ? _{\\varrho 0(x)} , wherebar ? _\\varrho , is the Gibbs state onA for an infinitely extended ideal Fermi gas at density ?, and where ?0 is the normalised density function that minimises the Thomas-Fermi functional, obtained in [2], governing the equilibrium thermodynamics of the system.

Narnhofer, Heide; Sewell, Geoffrey L.

1980-02-01

255

Hardy-Weinberg equilibrium diagnostics.  

PubMed

We propose two diagnostics for the statistical assessment of Hardy-Weinberg equilibrium. One diagnostic is the posterior probability of the complement of the smallest highest posterior density credible region that includes points in the parameter space consistent with the hypothesis of equilibrium. The null hypothesis of equilibrium is to be rejected if this probability is less than a pre-selected critical level. The second diagnostic is the proportion of the parameter space occupied by the highest posterior density credible region associated with the critical level. These Bayesian diagnostics can be interpreted as analogues of the classical types I and II error probabilities. They are broadly applicable: they can be computed for any hypothesis test, using samples of any size generated according to any distribution. PMID:12408944

Rogatko, André; Slifker, Michael J; Babb, James S

2002-11-01

256

Equilibrium relations and bipolar fuzzy clustering  

Microsoft Academic Search

Equilibrium relations bipolar fuzzy sets are introduced. Equilibrium relations are bipolar reflexive, symmetrical, and transitive. It is proved that: (1) crisp equilibrium relations induce hard partitions of harmony sets, coalition sets, and conflict sets; and (2) fuzzy equilibrium relation induces fuzzy harmony, coalition, and conflict sets which can be either disjoint or overlapped. Conditions for disjoint bipolar fuzzy partitioning are

Wen-Ran Zhang

1999-01-01

257

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

258

A quantitative tool to distinguish isobaric leucine and isoleucine residues for mass spectrometry-based de novo monoclonal antibody sequencing.  

PubMed

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. PMID:24845350

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

2014-07-01

259

Equilibrium in the Jungle &ast  

Microsoft Academic Search

In the jungle, power and coercion govern the exchange of resources. We study a simple, stylised model of the jungle that mirrors an exchange economy. We define the notion of jungle equilibrium and demonstrate that a number of standard results of competitive markets hold in the jungle.

Michele Piccione; Ariel Rubinstein

2007-01-01

260

An investigation of equilibrium concepts  

NASA Technical Reports Server (NTRS)

A different approach to modeling of the thermochemistry of rocket engine combustion phenomena is presented. The methodology described is based on the hypothesis of a new variational principle applicable to compressible fluid mechanics. This hypothesis is extended to treat the thermochemical behavior of a reacting (equilibrium) gas in an open system.

Prozan, R. J.

1982-01-01

261

Equilibrium Thermodynamics of Lattice QCD  

E-print Network

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.

D. K. Sinclair

2007-01-14

262

Magnetospheric equilibrium with anisotropic pressure  

SciTech Connect

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.

Cheng, C.Z.

1991-07-01

263

Non-equilibrium statistical thermodynamics  

Microsoft Academic Search

By suggesting that gas kinetic collisions are the source of irreversibility, Boltzmann's kinetic equation leads to a paradox. In a monograph entitled Non-equilibrium statistical thermodynamics, applied to fluid dynamics and laser physics the author developed an original alternative theory. The fundamental ideas supporting this new approach are traced in the present paper. It is shown that the source of irreversibility

X. de Hemptinne

1995-01-01

264

Testing calibrated general equilibrium models  

Microsoft Academic Search

This paper illustrates the philosophy which forms the basis of calibration exercises in general equilibrium macroeconomic models and the details of the procedure, the advantages and the disadvantages of the approach, with particular reference to the issue of testing ``false'' economic models. We provide an overview of the most recent simulation--based approaches to the testing problem and compare them to

Fabio Canova; Eva Ortega

1996-01-01

265

Equilibrium Statistical Mechanics Giovanni Gallavotti  

E-print Network

Equilibrium Statistical Mechanics Giovanni Gallavotti I.N.F.N. Roma 1, Fisica Roma1 1. Foundations: atoms and molecules Classical Statistical Mechanics studies properties of macroscopic aggregates the foundations of statistical mechanics have been laid on proper- ties, proved or assumed, of few particles

Roma "La Sapienza", Università di

266

Equilibrium Statistical Mechanics Giovanni Gallavotti  

E-print Network

Equilibrium Statistical Mechanics Giovanni Gallavotti I.N.F.N. Roma 1, Fisica Roma1 1. Foundations: atoms and molecules Classical Statistical Mechanics studies properties of macroscopic aggregates the foundations of statistical mechanics have been laid on proper­ ties, proved or assumed, of few particles

Roma "La Sapienza", Università di

267

Non-equilibrium work relations  

E-print Network

This is a brief review of recently derived relations describing the behaviour of systems far from equilibrium. They include the Fluctuation Theorem, Jarzynski's and Crooks' equalities, and an extended form of the Second Principle for general steady states. They are very general and their proofs are, in most cases, disconcertingly simple.

Jorge Kurchan

2005-11-03

268

Pattern formation outside of equilibrium  

Microsoft Academic Search

A comprehensive review of spatiotemporal pattern formation in systems driven away from equilibrium is presented, with emphasis on comparisons between theory and quantitative experiments. Examples include patterns in hydrodynamic systems such as thermal convection in pure fluids and binary mixtures, Taylor-Couette flow, parametric-wave instabilities, as well as patterns in solidification fronts, nonlinear optics, oscillatory chemical reactions and excitable biological media.

M. C. Cross; P. C. Hohenberg

1993-01-01

269

Equilibrium problems for Raney densities  

E-print Network

The Raney numbers are a class of combinatorial numbers generalising the Fuss--Catalan numbers. They are indexed by a pair of positive real numbers $(p,r)$ with $p>1$ and $0 equilibrium problems characterising the Raney densities for $(p,r) = (\\theta +1,1)$ and $(\\theta/2+1,1/2)$ have recently been proposed. Using two different techniques --- one based on the Wiener--Hopf method for the solution of integral equations and the other on an analysis of the algebraic equation satisfied by the Green's function --- we establish the validity of the equilibrium problems for general $\\theta > 0$ and similarly use both methods to identify the equilibrium problem for $(p,r) = (\\theta/q+1,1/q)$, $\\theta > 0$ and $q \\in \\mathbb Z^+$. The Wiener--Hopf method is used to extend the latter to parameters $(p,r) = (\\theta/q + 1, m+ 1/q)$ for $m$ a non-negative integer, and also to identify the equilibrium problem for a family of densities with moments given by certain binomial coefficients.

Peter J. Forrester; Dang-Zheng Liu; Paul Zinn-Justin

2014-11-15

270

Equilibrium mechanics of rotating systems  

Microsoft Academic Search

Equilibrium rotations of a planar kinematic chain undergoing a single degree of freedom (out of plane) rotation in a gravitational field are studied. Sharp bounds on the number of dynamic equilibria are given, and the dependence of this number on physical parameters is discussed for the special case of two-link chains and chains with identical links. The theory indicates that

John Baillieul

1987-01-01

271

Vaporizing Liquid Microthruster Concept: Preliminary Results of Initial Feasibility Studies  

Microsoft Academic Search

Introduction Chip Design and Fabrication Heater Characterization Description of Experiment Results Propellant Vaporization: Initial Studies Description of Experiment Preliminary Results Preliminary Conclusions and Future Work References

Juergen Mueller; Indrani Chakraborty; David Bame; William Tang

2000-01-01

272

Vaporizing Liquid Microthruster Concept: Preliminary Results of Initial Feasibility Studies  

NASA Astrophysics Data System (ADS)

Introduction Chip Design and Fabrication Heater Characterization Description of Experiment Results Propellant Vaporization: Initial Studies Description of Experiment Preliminary Results Preliminary Conclusions and Future Work References

Mueller, Juergen; Chakraborty, Indrani; Bame, David; Tang, William

273

Isospin Splitting of the Giant Dipole Resonance Built on the Isobaric Analog State from Pion Double Charge Exchange on NIOBIUM-93.  

NASA Astrophysics Data System (ADS)

We report the observation of the giant dipole resonance built on the isobaric analogue state (GDR otimesIAS) and the double dipole resonance (GDRotimesGDR). Data analysis shows that these two giant resonances were observed in ( pi^+,pi^-) double charge exchange (at T_{pi} = 292 MeV) on ^{93}Nb at excitation energies of 33.2 and 48.3 MeV (Q = -35.8 and -50.9 MeV). Angular distributions were measured for the resonances and each was observed to have a dipole shape and agree well with theoretical predictions. We also report the observation of the isospin splitting of the GDRotimesIAS into two of its three isospin components. Data analysis shows that two resonances were observed in (pi ^+,pi^-) double charge exchange (at T_{pi} = 292 MeV) on ^{93}Nb at excitation energies of 32.6 and 35.8 MeV (Q = -35.2 and -38.4 MeV). The cross sections for each component agreed very well with predicted calculations. We also report the observation of the double isobaric analog state (DIAS) as well as a resonance below the DIAS having a cross section of ~23% of the DIAS in ^{93}Tc. Analysis shows this resonance at an excitation energy of 15.0 MeV (Q = -17.6 MeV). We identify this resonance as the isobaric analogue of a simple T_ {<} configuration with shell structure characterized by the target state. Angular distributions were made of this state and the DIAS and both compared well with theoretical calculations.

Snell, Michael Paul

274

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

PubMed Central

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

Imbelloni, Luiz Eduardo; Gouveia, Marildo A.

2014-01-01

275

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

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.

Manley, D.M.

1981-11-01

276

Equilibrium cluster formation and gelation  

E-print Network

We study the formation and growth of equilibrium clusters in a suspension of weakly-charged colloidal particles and small non-adsorbing polymers. The effective potential is characterised by a short-range attraction and a long-range repulsion. The size, shape and local structure of the clusters are studied using three-dimensional particle microscopy. We observe a rapid growth in the mean cluster size and the average number of nearest neighbours approaching the gel boundary.

Rodrigo Sanchez; Paul Bartlett

2005-06-22

277

Nash equilibrium with strategic complementarities  

Microsoft Academic Search

Using lattice-theoretical methods, we analyze the existence and order structure of Nash equilibria of non-cooperative games where payoffs satisfy certain monotonicity properties (which are directly related to strategic complementarities) but need not be quasiconcave. In games with strategic complementarities the equilibrium set is always non-empty and has an order structure which ranges from the existence of a minimum and a

Xavier Vives

1990-01-01

278

Parametric study and characterization of the isobaric thermomechanical transformation fatigue of nickel-rich NiTi SMA actuators  

NASA Astrophysics Data System (ADS)

The recent development of various aerospace applications utilizing Ni-rich NiTi Shape memory Alloys (SMAs) as actuators motivated the need to characterize the cyclic response and the transformation fatigue behavior of such alloys. The fatigue life validation and certification of new designs is required in order to be implemented and used in future applications. For that purpose, a custom built fatigue test frame was designed to perform isobaric thermally induced transformation cycles on small dogbones SMA actuators (test gauge cross-section up to: 1.270 x 0.508 mm2). A parametric study on the cyclic response and transformation fatigue behavior of Ni-rich NiTi SMAs led to the optimization of several material/process and test parameters, namely: the applied stress range, the heat treatment, the heat treatment environment and the specimen thickness. However, fatigue testing was performed in a chilled waterless glycol environment maintained at a temperature of 5°C that showed evidence of corrosion-assisted transformation fatigue failure. Therefore, it was necessary to build a fatigue test frame that would employ a dry and inert cooling methodology to get away from any detrimental interactions between the specimens and the cooling medium (corrosion). The selected cooling method was gaseous nitrogen, sprayed into a thermally insulated chamber, maintaining a temperature of -20°C. The design of the gaseous nitrogen cooling was done in such a way that the actuation frequency is similar to the one obtained using the original design (~ 0.1 Hz). For both cooling methods, Joule resistive heating was used to heat the specimens. In addition and motivated by the difference in surface quality resulting from different material processing such as EDM wire cutting and heat treatments, EDM recast layer and oxide layer were removed. The removal was followed by an ultra-fine polish (0.05 ?m) that was performed on a subset of the fatigue specimens. Experimental results are presented for full actuation of the SMA actuators and are given in terms of applied stress, accumulated plastic strain and number of cycles to failure. In addition, the assessment of the influence of the surface quality is supported by fatigue tests results and post-failure microstructure analysis.

Bertacchini, Olivier W.; Schick, Justin; Lagoudas, Dimitris C.

2009-03-01

279

A Radio Frequency Quadrupole Instrument for use with Accelerator Mass Spectrometry: Application to Low Kinetic Energy Reactive Isobar Suppression and Gas--Phase Anion Reaction Studies  

NASA Astrophysics Data System (ADS)

A radio frequency (rf) quadrupole instrument, currently known as an Isobar Separator for Anions (ISA), has been integrated into an Accelerator Mass Spectrometry (AMS) system to facilitate anion--gas reactions before the tandem accelerator. An AMS Cs+ sputter source provided ? 15 keV ions that were decelerated in the prototype ISA to < 20 eV for reaction in a single collision cell and re-accelerated for AMS analysis. Reaction based isobar suppression capabilities were assessed for smaller AMS systems and a new technique for gas--phase reaction studies was developed. Isobar suppression of 36S-- and 12C3-- for 36Cl analysis, and YF3-- and ZrF3-- for 90Sr analysis were studied in NO2 with deceleration to ? 12 eV. Observed attenuation cross sections, sigma [x 10--15 cm2], were sigma(S-- + NO2) = 6.6, sigma(C3-- + NO2) = 4.2, sigma(YF3-- + NO 2) = 7.6, sigma(ZrF3-- + NO2) = 19. With 8 mTorr NO2, relative attenuations of S-- /Cl-- ˜ 10--6, C 3--/Cl-- ˜ 10--7 , YF3--/SrF3-- ˜ 5 x 10--5 and ZrF3-- /SrF3-- ˜ 4 x 10--6 were observed with Cl-- ˜ 30% and SrF 3-- > 90% transmission. Current isobar attenuation limits with ? 1.75 MV accelerator terminal voltage and ppm impurity levels were calculated to be 36S--/Cl-- ˜ 4 x 10--16, 12C3 --/Cl-- ˜ 1.2 x 10--16, 90YF3--/SrF3-- ˜ 10--15 and 90ZrF3 --/SrF3-- ˜ 10--16 . Using 1.75 MV, four 36Cl reference standards in the range 4 x 10--13 ? 36Cl/Cl ? 4 x 10 --11 were analyzed with 8 mTorr NO2. The measured 36Cl/Cl ratios plotted very well against the accepted values. A sample impurity content S/Cl ? 6 x 10--5 was measured and a background level of 36S--/Cl ? 9 x 10--15 was determined. Useful currents of a wide variety of anions are produced in AMS sputter sources and molecules can be identified relatively unambiguously by stripping fragments from tandem accelerators. Reactions involving YF3 --, ZrF3--, S-- and SO-- + NO2 in the ISA analyzed by AMS are described, and some interesting reactants are identified.

Eliades, John Alexander

280

Reflective equilibrium and the 'moral conservatism' objection  

E-print Network

of moral conservatism objection; that is, moral beliefs may appear to be coherent but wrong. What are the normative grounds for criticizing implausible beliefs that seem to be in equilibrium? Wide reflective equilibrium has been the traditional attempt...

Chandler, James Robert

2002-01-01

281

Equilibrium resource management with altruistic overlapping generations  

E-print Network

Equilibrium resource management with altruistic overlapping generations Ivar Ekeland Larry Karp rates, leading to time inconsistency. The unique Markov Perfect equilibrium to this model has a striking feature: provided that the current generation has some concern for the not-yet born, the equilibrium

Kammen, Daniel M.

282

Nash Equilibrium and Dynamics Sergiu Hart  

E-print Network

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

Hart, Sergiu

283

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

284

General equilibrium of financial markets: An introduction  

E-print Network

General equilibrium of financial markets: An introduction Monique Florenzano November 1999 CNRS. It is done studying in different contexts the general equilibrium of a sim- ple two-period exchange model. Sev- eral equilibrium existence theorems are stated and proved. Even in this simple framework

Paris-Sud XI, Université de

285

Oblivious Router Policies and Nash Equilibrium  

E-print Network

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

Rey Juan Carlos, Universidad

286

Spheromak Equilibrium Studies on SSX Cameron Geddes  

E-print Network

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

Geddes, Cameron Guy Robinson

287

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

E-print Network

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

Fiat, Amos

288

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

E-print Network

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

Fiat, Amos

289

Excitation of the ?(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV  

NASA Astrophysics Data System (ADS)

The charge-exchange break-up of polarised deuterons d?p?{pp}sn, where the final {pp}s diproton system has a very low excitation energy and hence is mainly in the S01 state, is a powerful tool to probe the spin-flip terms in the proton-neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the ?(1232) isobar in the d?p?{pp}sX reaction. Values of the differential cross section and two deuteron tensor analysing powers, Axx and Ayy, have been extracted as functions of the momentum transfer to the diproton or the invariant mass MX of the unobserved system X. The unpolarised cross section in the high MX region is well described in a model that includes only direct excitation of the ? isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low MX, even when ? excitation in the projectile deuteron is included in the calculation. Furthermore, direct ? production through one pion exchange only reproduces the angular dependence of the difference between the two tensor analysing powers.

Mchedlishvili, D.; Barsov, S.; Carbonell, J.; Chiladze, D.; Dymov, S.; Dzyuba, A.; Engels, R.; Gebel, R.; Glagolev, V.; Grigoryev, K.; Goslawski, P.; Hartmann, M.; Imambekov, O.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Khoukaz, A.; Komarov, V.; Kulessa, P.; Kulikov, A.; Lehrach, A.; Lomidze, N.; Lorentz, B.; Macharashvili, G.; Maier, R.; Merzliakov, S.; Mielke, M.; Mikirtychyants, M.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Papenbrock, M.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Seyfarth, H.; Stein, H. J.; Steffens, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Trusov, S.; Uzikov, Yu.; Valdau, Yu.; Wilkin, C.

2013-10-01

290

Conformations of Proteins in Equilibrium  

NASA Astrophysics Data System (ADS)

We introduce a simple theoretical approach for an equilibrium study of proteins with known native-state structures. We test our approach with results on well-studied globular proteins, chymotrypsin inhibitor (2ci2), barnase, and the alpha spectrin SH3 domain, and present evidence for a hierarchical onset of order on lowering the temperature with significant organization at the local level even at high temperatures. A further application to the folding process of HIV-1 protease shows that the model can be reliably used to identify key folding sites that are responsible for the development of drug resistance.

Micheletti, Cristian; Banavar, Jayanth R.; Maritan, Amos

2001-08-01

291

Far-From-Equilibrium Physics: An Overview  

E-print Network

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.

Heinrich M. Jaeger; Andrea J. Liu

2010-09-24

292

Chapter 9. Chemical Equilibrium 9.1 The Nature of Chemical Equilibrium  

E-print Network

Chapter 9. Chemical Equilibrium #12;9.1 The Nature of Chemical Equilibrium -Approach to Equilibrium [Co(H2O)6]2+ + 4 Cl- [CoCl4]2- + 6 H2O #12;Characteristics of the Equilibrium State example) H2O(l) H2 though the system in not at equilibrium. #12;9.2 The Empirical Law of Mass Action aA + bB cC + dD KC

Ihee, Hyotcherl

293

Non-equilibrium phase transitions  

SciTech Connect

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.

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

1998-12-31

294

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

SciTech Connect

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.

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

2010-01-10

295

Thermodynamic equilibrium at heterogeneous pressure  

NASA Astrophysics Data System (ADS)

Recent advances in metamorphic petrology point out the importance of grain-scale pressure variations in high-temperature metamorphic rocks. Pressures derived from chemical zonation using unconventional geobarometry based on equal chemical potentials fit 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 constraint Gibbs minimization using linear programming techniques. Compositions of phases considered in the calculation are discretized into 'pseudo-compounds' spanning the entire compositional space. Gibbs energies of these discrete compounds are generated for a given range and resolution of pressures for example derived by barometry or from mechanical model predictions. Gibbs energy minimization is subsequently performed considering all compounds of different composition and pressure. In addition to constraining the system composition a certain proportion of the system is constraint at a specified pressure. Input pressure variations need to be discretized and each discrete pressure defines an additional constraint for the minimization. The proportion of the system at each different pressure is equally distributed over the number of input pressures. For example if two input pressures P1 and P2 are specified, two constraints are added: 50 percent of the system is constraint at P1 while the remaining 50 percent is constraint at P2. The method has been tested for a set of 10 input pressures obtained by Taj?manová et al. (2014) using their unconventional geobarometry method in a plagioclase rim around kyanite. Each input pressure is added as constraint to the minimization (1/10 percent of the system for each discrete pressure). Constraining the system composition to the average composition of the plagioclase rim successfully predicts the observed chemical zoning. In conclusion, Gibbs minimization provides identical results to the 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. Reference: Taj?manová, L., Podladchikov, Y., Powell, R., Moulas, E., Vrijmoed, J. C. & Connolly, J. A. D. (2014). Grain scale pressure variations and chemical equilibrium in high-grade metamorphic rocks. Journal of Metamorphic Geology, (in press).

Vrijmoed, Johannes C.; Podladchikov, Yuri Y.

2014-05-01

296

Classical fields near thermal equilibrium  

SciTech Connect

We discuss the classical limit for the long-distance ({open_quotes}soft{close_quotes}) modes of a quantum field when the hard modes of the field are in thermal equilibrium. We address the question of the correct semiclassical dynamics when a momentum cutoff {vert_bar}{bold p}{vert_bar}{le}k{sub c}{lt}T is introduced. Higher order contributions lead to a stochastic interpretation for the effective action in analogy with quantum Brownian motion, resulting in dissipation and decoherence for the evolution of the soft modes. Particular emphasis is put on the understanding of dissipation. Our discussion focuses mostly on scalar fields, but we make some remarks on the extension to gauge theories. {copyright} {ital 1997} {ital The American Physical Society}

Greiner, C. [Institut fuer Theoretische Physik, Justus-Liebig-Universitaet Giessen, D-35392 Giessen (Germany)] [Institut fuer Theoretische Physik, Justus-Liebig-Universitaet Giessen, D-35392 Giessen (Germany); Mueller, B. [Department of Physics, Duke University, Durham, North Carolina 27708-0305 (United States)] [Department of Physics, Duke University, Durham, North Carolina 27708-0305 (United States)

1997-01-01

297

Equilibrium calculations of firework mixtures  

SciTech Connect

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.

Hobbs, M.L. [Sandia National Labs., Albuquerque, NM (United States); Tanaka, Katsumi; Iida, Mitsuaki; Matsunaga, Takehiro [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan)

1994-12-31

298

Local non-equilibrium thermodynamics.  

PubMed

Local Shannon entropy lies at the heart of modern thermodynamics, with much discussion of trajectory-dependent entropy production. When taken at both boundaries of a process in phase space, it reproduces the second law of thermodynamics over a finite time interval for small scale systems. However, given that entropy is an ensemble property, it has never been clear how one can assign such a quantity locally. Given such a fundamental omission in our knowledge, we construct a new ensemble composed of trajectories reaching an individual microstate, and show that locally defined entropy, information, and free energy are properties of the ensemble, or trajectory-independent true thermodynamic potentials. We find that the Boltzmann-Gibbs distribution and Landauer's principle can be generalized naturally as properties of the ensemble, and that trajectory-free state functions of the ensemble govern the exact mechanism of non-equilibrium relaxation. PMID:25592077

Jinwoo, Lee; Tanaka, Hajime

2015-01-01

299

Hierarchical condensation near phase equilibrium  

NASA Astrophysics Data System (ADS)

A novel mechanism of new phase formation is studied both experimentally and theoretically in the example of quasi-equilibrium stationary condensation in an ion-plasma sputterer. Copper condensates are obtained to demonstrate that a specific network structure is formed as a result of self-assembly in the course of deposition. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. The Langevin equation and the Fokker-Planck equation related are found to describe stationary distribution of thermodynamic potential variations at condensation. Time dependence of the formation probability of branching structures is found to clarify the experimental situation.

Olemskoi, A. I.; Yushchenko, O. V.; Borisyuk, V. N.; Zhilenko, T. I.; Kosminska, Yu. O.; Perekrestov, V. I.

2012-06-01

300

Local non-equilibrium thermodynamics  

PubMed Central

Local Shannon entropy lies at the heart of modern thermodynamics, with much discussion of trajectory-dependent entropy production. When taken at both boundaries of a process in phase space, it reproduces the second law of thermodynamics over a finite time interval for small scale systems. However, given that entropy is an ensemble property, it has never been clear how one can assign such a quantity locally. Given such a fundamental omission in our knowledge, we construct a new ensemble composed of trajectories reaching an individual microstate, and show that locally defined entropy, information, and free energy are properties of the ensemble, or trajectory-independent true thermodynamic potentials. We find that the Boltzmann-Gibbs distribution and Landauer's principle can be generalized naturally as properties of the ensemble, and that trajectory-free state functions of the ensemble govern the exact mechanism of non-equilibrium relaxation.

Jinwoo, Lee; Tanaka, Hajime

2015-01-01

301

Passive equilibrium studies on ZT-P  

SciTech Connect

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.

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

1987-12-01

302

Isobaric-Isothermal Molecular Dynamics Utilizing Density Functional Theory: An Assessment of the Structure and Density of Water at Near-Ambient Conditions  

SciTech Connect

We present herein a comprehensive density functional theory study toward assessing the accuracy of two popular gradient-corrected exchange correlation functionals on the structure and density of liquid water at near ambient conditions in the isobaric-isothermal ensemble. Our results indicate that both PBE and BLYP functionals under predict the density and over structure the liquid. Adding the dispersion correction due to Grimme(1, 2) improves the predicted densities for both BLYP and PBE in a significant manner. Moreover, the addition of the dispersion correction for BLYP yields an oxygen-oxygen radial distribution function in excellent agreement with experiment. Thus, we conclude that one can obtain a very satisfactory model for water using BLYP and a correction for dispersion.

Schmidt, J; VandeVondele, J; Kuo, I W; Sebastiani, D; Siepmann, J I; Hutter, J; Mundy, C J

2009-03-06

303

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)

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.

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

2014-05-01

304

Positive parity states in {sup 208}Pb excited by the proton decay of the isobaric analog intruder resonance j{sub 15/2} in {sup 209}Bi  

SciTech Connect

With the Q3D magnetic spectrograph of the Maier-Leibnitz-Laboratorium at Muenchen at a resolution of about 3 keV, angular distributions and excitation functions of the reaction {sup 208}Pb(p,p{sup '}) were measured at some scattering angles 20 deg. - 138 deg. for several proton energies 14.8-18.1 MeV. All seven known isobaric analog resonances in {sup 209}Bi are covered. By the excitation near the j{sub 15/2} intruder resonance in {sup 209}Bi, several new positive parity states in {sup 208}Pb with excitation energies 4.6-6.2 MeV are identified by comparison of the mean cross section to the known single particle widths. The dominant configuration for 27 positive parity states is determined and compared to the schematic shell model.

Heusler, A. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Graw, G.; Hertenberger, R.; Riess, F.; Wirth, H.-F. [Fakultaet fuer Physik, Ludwig-Maximilians--Universitaet Muenchen, D-85748 Garching (Germany); Faestermann, T.; Kruecken, R.; Behrens, T.; Bildstein, V.; Eppinger, K.; Herlitzius, C.; Lepyoshkina, O.; Mahgoub, M.; Parikh, A.; Schwertel, S.; Wimmer, K. [Physik Department E12, Technische Universitaet Muenchen, D-85748 Garching (Germany); Pietralla, N. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Werner, V. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520-8120 (United States); Jolie, J.; Muecher, D. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany)

2010-07-15

305

Sulfonium ion derivatization, isobaric stable isotope labeling and data dependent CID- and ETD-MS/MS for enhanced phosphopeptide quantitation, identification and phosphorylation site characterization.  

PubMed

An amine specific peptide derivatization strategy involving the use of novel isobaric stable isotope encoded 'fixed charge' sulfonium ion reagents, coupled with an analysis strategy employing capillary HPLC, ESI-MS, and automated data dependent ion trap CID-MS/MS, -MS(3), and/or ETD-MS/MS, has been developed for the improved quantitative analysis of protein phosphorylation, and for identification and characterization of their site(s) of modification. Derivatization of 50 synthetic phosphopeptides with S,S'-dimethylthiobutanoylhydroxysuccinimide ester iodide (DMBNHS), followed by analysis using capillary HPLC-ESI-MS, yielded an average 2.5-fold increase in ionization efficiencies and a significant increase in the presence and/or abundance of higher charge state precursor ions compared to the non-derivatized phosphopeptides. Notably, 44% of the phosphopeptides (22 of 50) in their underivatized states yielded precursor ions whose maximum charge states corresponded to +2, while only 8% (4 of 50) remained at this maximum charge state following DMBNHS derivatization. Quantitative analysis was achieved by measuring the abundances of the diagnostic product ions corresponding to the neutral losses of 'light' (S(CH(3))(2)) and 'heavy' (S(CD(3))(2)) dimethylsulfide exclusively formed upon CID-MS/MS of isobaric stable isotope labeled forms of the DMBNHS derivatized phosphopeptides. Under these conditions, the phosphate group stayed intact. Access for a greater number of peptides to provide enhanced phosphopeptide sequence identification and phosphorylation site characterization was achieved via automated data-dependent CID-MS(3) or ETD-MS/MS analysis due to the formation of the higher charge state precursor ions. Importantly, improved sequence coverage was observed using ETD-MS/MS following introduction of the sulfonium ion fixed charge, but with no detrimental effects on ETD fragmentation efficiency. PMID:21952753

Lu, Yali; Zhou, Xiao; Stemmer, Paul M; Reid, Gavin E

2012-04-01

306

Sulfonium Ion Derivatization, Isobaric Stable Isotope Labeling and Data Dependent CID- and ETD-MS/MS for Enhanced Phosphopeptide Quantitation, Identification and Phosphorylation Site Characterization  

NASA Astrophysics Data System (ADS)

An amine specific peptide derivatization strategy involving the use of novel isobaric stable isotope encoded `fixed charge' sulfonium ion reagents, coupled with an analysis strategy employing capillary HPLC, ESI-MS, and automated data dependent ion trap CID-MS/MS, -MS3, and/or ETD-MS/MS, has been developed for the improved quantitative analysis of protein phosphorylation, and for identification and characterization of their site(s) of modification. Derivatization of 50 synthetic phosphopeptides with S, S'-dimethylthiobutanoylhydroxysuccinimide ester iodide (DMBNHS), followed by analysis using capillary HPLC-ESI-MS, yielded an average 2.5-fold increase in ionization efficiencies and a significant increase in the presence and/or abundance of higher charge state precursor ions compared to the non-derivatized phosphopeptides. Notably, 44% of the phosphopeptides (22 of 50) in their underivatized states yielded precursor ions whose maximum charge states corresponded to +2, while only 8% (4 of 50) remained at this maximum charge state following DMBNHS derivatization. Quantitative analysis was achieved by measuring the abundances of the diagnostic product ions corresponding to the neutral losses of `light' (S(CH3)2) and `heavy' (S(CD3)2) dimethylsulfide exclusively formed upon CID-MS/MS of isobaric stable isotope labeled forms of the DMBNHS derivatized phosphopeptides. Under these conditions, the phosphate group stayed intact. Access for a greater number of peptides to provide enhanced phosphopeptide sequence identification and phosphorylation site characterization was achieved via automated data-dependent CID-MS3 or ETD-MS/MS analysis due to the formation of the higher charge state precursor ions. Importantly, improved sequence coverage was observed using ETD-MS/MS following introduction of the sulfonium ion fixed charge, but with no detrimental effects on ETD fragmentation efficiency.

Lu, Yali; Zhou, Xiao; Stemmer, Paul M.; Reid, Gavin E.

2012-04-01

307

1 stepped pressure equilibrium code : hdfint 1 stepped pressure equilibrium code : hdfint 1  

E-print Network

1 stepped pressure equilibrium code : hdfint Contents 1 stepped pressure equilibrium code : hdfint enclosed by each interface; · pressure(1:Nvol); real; pressure in each volume; · iota(1:Nvol); real

Hudson, Stuart

308

EASI - EQUILIBRIUM AIR SHOCK INTERFERENCE  

NASA Technical Reports Server (NTRS)

New research on hypersonic vehicles, such as the National Aero-Space Plane (NASP), has raised concerns about the effects of shock-wave interference on various structural components of the craft. State-of-the-art aerothermal analysis software is inadequate to predict local flow and heat flux in areas of extremely high heat transfer, such as the surface impingement of an Edney-type supersonic jet. EASI revives and updates older computational methods for calculating inviscid flow field and maximum heating from shock wave interference. The program expands these methods to solve problems involving the six shock-wave interference patterns on a two-dimensional cylindrical leading edge with an equilibrium chemically reacting gas mixture (representing, for example, the scramjet cowl of the NASP). The inclusion of gas chemistry allows for a more accurate prediction of the maximum pressure and heating loads by accounting for the effects of high temperature on the air mixture. Caloric imperfections and specie dissociation of high-temperature air cause shock-wave angles, flow deflection angles, and thermodynamic properties to differ from those calculated by a calorically perfect gas model. EASI contains pressure- and temperature-dependent thermodynamic and transport properties to determine heating rates, and uses either a calorically perfect air model or an 11-specie, 7-reaction reacting air model at equilibrium with temperatures up to 15,000 K for the inviscid flowfield calculations. EASI solves the flow field and the associated maximum surface pressure and heat flux for the six common types of shock wave interference. Depending on the type of interference, the program solves for shock-wave/boundary-layer interaction, expansion-fan/boundary-layer interaction, attaching shear layer or supersonic jet impingement. Heat flux predictions require a knowledge (from experimental data or relevant calculations) of a pertinent length scale of the interaction. Output files contain flow-field information for the various shock-wave interference patterns and their associated maximum surface pressure and heat flux predictions. EASI is written in FORTRAN 77 for a DEC VAX 8500 series computer using the VAX/VMS operating system, and requires 75K of memory. The program is available on a 9-track 1600 BPI magnetic tape in DEC VAX BACKUP format. EASI was developed in 1989. DEC, VAX, and VMS are registered trademarks of the Digital Equipment Corporation.

Glass, C. E.

1994-01-01

309

Equilibrium coexistence of three amphiboles  

USGS Publications Warehouse

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.

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

1969-01-01

310

Partial equilibrium approximations in Apoptosis  

E-print Network

Apoptosis is one of the most basic biological processes. In apoptosis, tens of species are involved in many biochemical reactions with times scales of widely differing orders of magnitude. By the law of mass action, the process is mathematically described with a large and stiff system of ODEs (ordinary differential equations). The goal of this work is to simplify such systems of ODEs with the PEA (partial equilibrium approximation) method. In doing so, we propose a general framework of the PEA method together with some conditions, under which the PEA method can be justified rigorously. The main condition is the principle of detailed balance for fast reactions as a whole. With the justified method as a tool, we made many attempts via numerical tests to simplify the Fas-signaling pathway model due to Hua et al. (2005) and found that nine of reactions therein can be well regarded as relatively fast. This paper reports our simplification of Hua at el.'s model with the PEA method based on the fastness of the nine ...

Huang, Ya-Jing

2012-01-01

311

Zeroth Law, Entropy, Equilibrium, and All That  

ERIC Educational Resources Information Center

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…

Canagaratna, Sebastian G.

2008-01-01

312

Non-equilibrium properties of hadronic mixtures  

Microsoft Academic Search

The equilibration of hot hadronic matter is studied in the framework of relativistic kinetic theory. Various non-equilibrium properties of a mixture comprised of pions, kaons and nucleons are calculated in the dilute limit for small deviations from local thermal equilibrium. Interactions between these constituents are specified through the empirical phase shifts. The properties calculated include the relaxation\\/collision times, momentum and

Madappa Prakash; Manju Prakash; Raju Venugopalan; Gerd Welke

1993-01-01

313

Pretirage INLN..... Non equilibrium statistical mechanics  

E-print Network

1 Pr´etirage INLN..... Non equilibrium statistical mechanics Michel Le Bellac Institut Non Lin In part I of these lecture notes, I introduce the basic tools of non equilibrium statistical mechanics statistical mechanics, all thermodynamics properties are derived from the partition func- tion: once

Paris-Sud XI, Université de

314

NonEquilibrium Thermodynamics Explains Semiotic Shapes  

E-print Network

Non­Equilibrium Thermodynamics Explains Semiotic Shapes: Applications to Astronomy and to Non­destructive testing of aerospace systems. KEYWORDS: astrogeometry, semiotics, symmetry groups, non­equilibrium thermodynamics, non­destructive testing, aerospace structures 1. SEMIOTIC SHAPES IN ASTRONOMY: FORMULATION

Kreinovich, Vladik

315

Calibration and Nash Equilibrium Dean Foster  

E-print Network

September 22, 2005 #12;What is a Nash equilibrium? · Cartoon definition of NE: ­ Leroy Lockhorn: "I definition of NE: ­ If everyone else will play the Nash equilibrium, then I should play it also. ­ Holds the forecast probability of precipitation was, say, close to some given value p and then determine the long run

Foster, Dean P.

316

Equilibrium : ConcFromKsp (8 Variations)  

NSDL National Science Digital Library

The K sp of BaF 2 is 1.7 x 10 -6 mol/L in water at 25 o C. What is the concentration of barium ions in equilibrium with solid barium fluoride? (Assume that the only relevant reaction is the solubility-product equilibrium.)

317

Sensitivity theory for the equilibrium burnup cycle  

Microsoft Academic Search

The design and analysis of advanced reactor concepts are based on the performance of the equilibrium cycle (sometimes also referred to as they cyclic mode of the reactor), rather than some arbitrary sequence of start-up cycles. While sensitivity theory has been developed for a sequence of nonequilibrium (or initial value) depletion problems, the equilibrium problem has not been previously considered.

W. S. Yang; T. J. Downar

1989-01-01

318

Refinements of the Nash equilibrium concept  

Microsoft Academic Search

Selten's concept of perfect equilibrium for normal form games is reviewed, and a new concept of proper equilibrium is defined. It is shown that the proper equilibria form a nonempty subset of the perfect equilibria, which in turn form a subset of the Nash equilibria. An example is given to show that these inclusions may be strict.

R. B. Myerson

1978-01-01

319

Disturbances in equilibrium function after major earthquake  

PubMed Central

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. PMID:23087814

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

2012-01-01

320

Disturbances in equilibrium function after major earthquake  

NASA Astrophysics Data System (ADS)

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.

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

2012-10-01

321

Local Nash Equilibrium in Social Networks  

PubMed Central

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

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

2014-01-01

322

The Conceptual Change Approach to Teaching Chemical Equilibrium  

ERIC Educational Resources Information Center

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…

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

2006-01-01

323

Energy Spectrum of equilibrium Black Holes  

E-print Network

Taking cue from the knowledge of the quantum theory of gravity at our disposal in the form of loop quantum gravity, a model Hamiltonian operator for the quantum theory of equilibrium black hole horizons, modeled as isolated horizons, is proposed. Using equilibrium statistical mechanical methods we derive the first law of isolated horizon mechanics. Seeking that the result should be compatible with the one derived from the classical theory, the unknown coefficients and parameters of the Hamiltonian operator are fixed, yielding the energy spectrum of equilibrium black holes.

Abhishek Majhi

2014-09-20

324

What's quasi-equilibrium all WhatWhatWhat'''s quasis quasis quasi---equilibrium allequilibrium allequilibrium all  

E-print Network

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

Plant, Robert

325

STP Lennard-Jones Thermal Equilibrium Program  

NSDL National Science Digital Library

The STP LJ Thermal Equilibrium program simulates the interaction between two systems of Lennard-Jones particles brought into thermal contact. The purpose of this simulation is to explore the nature of thermal equilibrium and the relation, if any, between the kinetic and potential energies of two systems in thermal contact. The two initially isolated systems have 81 (red) and 64(green) particles by default. STP LJThermalEquilibrium is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the stp_LJThermalEquilibrium.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2009-03-13

326

Equilibrium Reconstruction on the Large Helical Device  

SciTech Connect

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.

Samuel A. Lazerson, D. Gates, D. Monticello, H. Neilson, N. Pomphrey, A. Reiman S. Sakakibara, and Y. Suzuki

2012-07-27

327

The Physics Classroom: Equilibrium and Statics  

NSDL National Science Digital Library

This website offers a lesson explaining statics and equilibrium. Graphs, figures, and images are dispersed throughout the lesson to facilitate comprehension along with a quiz at the end to assess student understanding.

Henderson, Tom

2006-07-06

328

Adaptive radiation: convergence and non-equilibrium.  

PubMed

The spectacular adaptive radiation of cichlid fish in Lake Tanganyika encompasses extensive morphological convergence and co-occurrence of ecologically similar species, forcing a reevaluation of non-equilibrium dynamics in community assembly. PMID:23347943

Gillespie, Rosemary G

2013-01-21

329

Chemistry 365: Equilibrium in Thermodynamics David Ronis  

E-print Network

Chemistry 365: Equilibrium in Thermodynamics © David Ronis McGill University Here we will review by combining the logs on the left and exponentiating, we obtain Winter Term, 2015 #12;Chemistry 365 -2

Ronis, David M.

330

Edge Equilibrium Code (EEC) For Tokamaks  

SciTech Connect

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

Li, Xujling

2014-02-24

331

Quasi-equilibrium in tapered chains  

Microsoft Academic Search

The approach to equilibrium in 1d lattices is interesting for granular media since temperature is not well-defined and various authors have reported a violation of equipartition. We extend our previous work on shock mitigation in tapered chains to look at energy sharing among spheres and how the system appraoches a so-called quasi-equilibrium. An overlap potential of adjacent particles is used

Robert Doney; Surajit Sen

2007-01-01

332

MCZ 041103 1 Equilibrium and Stability of  

E-print Network

and not limited by onset of observable MHD · What limits the observed value? #12;MCZ 041103 6 Reconstructed Self No current · STELLOPT/VMEC design-optimization code adapted to be a free-boundary equilibrium reconstruction/IM = 0.15 = 2.0% ICC/IM = 0.15 = 2.7% · PIES equilibrium analysis using fixed pressure profile from

333

Dynamically defined measures and equilibrium states  

E-print Network

A technique of dynamically defined measures is developed and its relation to the theory of equilibrium states is shown. The technique uses Caratheodory's method and the outer measure introduced in (I. Werner, Math. Proc. Camb. Phil. Soc. 140 (2) (2006) 333-347). As an application, equilibrium states for contractive Markov systems (I. Werner, J. London Math. Soc. 71 (2005), no. 1, 236-258) are obtained.

Ivan Werner

2014-11-09

334

Equilibrium fluctuation energy of gyrokinetic plasma  

SciTech Connect

The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result (k)/8..pi.. = 1/2T/(1 + (klambda/sub D/)/sup 2/) valid for arbitrarily magnetized plasmas. It is shown that, in a certain sense, the equilibrium electric field energy is minimum in the gyrokinetic regime. 13 refs., 2 figs.

Krommes, J.A.; Lee, W.W.; Oberman, C.

1985-11-01

335

Theory for non-equilibrium statistical mechanics.  

PubMed

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

Attard, Phil

2006-08-21

336

Isobaric-Isothermal Molecular Dynamics Simulations Utilizing Density Functional Theory: An Assessment of the Structure and Density of Water at Near-Ambient Conditions  

SciTech Connect

We present herein, a comprehensive density functional theory study towards assessing the accuracy of two popular gradient corrected exchange correlation functionals on the structure and density of liquid water at near ambient conditions in the isobaric-isotherma ensemble. Our results indicate that both PBE and BLYP functionals underpredict the density and overstructure the liquid. Adding the dispersion correction due to Grimme [1, 2] improves the predicted densities for both BLYP and PBE in a significant manner. Moreover, the addition of the dispersion correction for BLYP yields an oxygen-oxygen radial distribution function in excellent agreement with experiment. Thus, we conclude that one can obtain a very satisfactory model for water using BLYP and a correction for dispersion. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Chemical Sciences program, and was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.

Schmidt, Jochen; VandeVondele, Joost; Kuo, I-F W.; Sebastiani, Daniel; Siepmann, Joern L.; hutter, juerg; Mundy, Christopher J.

2009-09-03

337

Quantitative Proteomic Analysis of Serum from Pregnant Women Carrying a Fetus with Conotruncal Heart Defect Using Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Labeling  

PubMed Central

Objective To identify differentially expressed proteins from serum of pregnant women carrying a conotruncal heart defects (CTD) fetus, using proteomic analysis. Methods The study was conducted using a nested case-control design. The 5473 maternal serum samples were collected at 14–18 weeks of gestation. The serum from 9 pregnant women carrying a CTD fetus, 10 with another CHD (ACHD) fetus, and 11 with a normal fetus were selected from the above samples, and analyzed by using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with two-dimensional liquid chromatography-tandem mass spectrometry(2D LC-MS/MS). The differentially expressed proteins identified by iTRAQ were further validated with Western blot. Results A total of 105 unique proteins present in the three groups were identified, and relative expression data were obtained for 92 of them with high confidence by employing the iTRAQ-based experiments. The downregulation of gelsolin in maternal serum of fetus with CTD was further verified by Western blot. Conclusions The identification of differentially expressed protein gelsolin in the serum of the pregnant women carrying a CTD fetus by using proteomic technology may be able to serve as a foundation to further explore the biomarker for detection of CTD fetus from the maternal serum. PMID:25393621

Zhang, Ying; Kang, Yuan; Zhou, Qiongjie; Zhou, Jizi; Wang, Huijun; Jin, Hong; Liu, Xiaohui; Ma, Duan; Li, Xiaotian

2014-01-01

338

Development of a thermal equilibrium prediction algorithm.  

SciTech Connect

A thermal equilibrium prediction algorithm is developed and tested using a heat conduction model and data sets from calorimetric measurements. The physical model used in this study is the exact solution of a system of two partial differential equations that govern the heat conduction in the calorimeter. A multi-parameter estimation technique is developed and implemented to estimate the effective volumetric heat generation and thermal diffusivity in the calorimeter measurement chamber, and the effective thermal diffusivity of the heat flux sensor. These effective properties and the exact solution are used to predict the heat flux sensor voltage readings at thermal equilibrium. Thermal equilibrium predictions are carried out considering only 20% of the total measurement time required for thermal equilibrium. A comparison of the predicted and experimental thermal equilibrium voltages shows that the average percentage error from 330 data sets is only 0.1% . The data sets used in this study come from calorimeters of different sizes that use different kinds of heat flux sensors. Furthermore, different nuclear material matrices were assayed in the process of generating these data sets. This study shows that the integration of this algorithm into the calorimeter data acquisition software will result in an 80% reduction of measurement time. This reduction results in a significant cutback in operational costs for the calorimetric assay of nuclear materials.

Aviles-Ramos, C. (Cuauhtemoc)

2001-01-01

339

A Coupled Model for Radiative Transfer: Doppler Effects, Equilibrium and Non-Equilibrium Diffusion Asymptotics  

E-print Network

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

Goudon, Thierry

340

Transferable force field for equilibrium and transport properties in linear and branched monofunctional and multifunctional amines. II. Secondary and tertiary amines.  

PubMed

Following the same philosophy of our previous force field for primary amines (J. Phys. Chem. B2011, 115, 14617), we present an extension for secondary and tertiary amines using the anisotropic united atom (AUA4) approach. The force field is developed to predict the phase equilibrium and transport properties of secondary and tertiary amines. The transferability was studied for an important set of molecules including as secondary amines dimethylamine, diethylamine, di-n-propylamine, di-iso-propylamine, and di-iso-butylamine. We have also tested diethylenetriamine, a multifunctional molecule which includes two primary and one secondary amino groups. For tertiary amines, we have included simulations for trimethylamine, triethylamine, tri-n-propylamine, and methyldiethylamine. Monte Carlo simulations in the Gibbs ensemble were carried out to study thermodynamic properties such as equilibrium densities, vaporization enthalpies, and vapor pressures. Critical coordinates (critical density and critical temperature) and normal boiling points were also calculated. The shear viscosity coefficients were studied for dimethyl, diethyl, di-n-propyl, trimethyl, triethyl, and tri-n-propylamine at different temperatures using molecular dynamics in the isothermal isobaric ensemble. Our results show a very good agreement with experimental values for all the studied molecules for both thermodynamic and transport properties, demonstrating the transferability of our force field. PMID:22551443

Orozco, Gustavo A; Nieto-Draghi, Carlos; Mackie, Allan D; Lachet, Véronique

2012-05-31

341

Equilibrium dialysis using chromophoric sugar derivatives.  

PubMed

Equilibrium dialysis has been used to examine the binding affinity of ligands to proteins. It is a simple and reliable method, which requires only inexpensive equipment. For analysis of lectin-sugar interactions, the lectin and sugar are placed in the individual chambers separated by the membrane to allow the sugar to diffuse into the lectin chamber. After equilibrium has been reached, the concentrations of the sugar in both chambers are determined to evaluate the sugar-binding affinity of lectin. In this chapter, an example of the equilibrium dialysis experiment using the chromophoric derivatives of galactose and N-acetylgalactosamine is demonstrated, which reveals the difference in the affinity as well as specificities of two different carbohydrate-binding sites present in the B-chains of the plant lectin ricin. PMID:25117234

Hatakeyama, Tomomitsu

2014-01-01

342

Navigating Personal and Relational Concerns: The Quest for Equilibrium  

Microsoft Academic Search

The authors' personal–relational equilibrium model suggests that people come to seek equilibrium in their dedication to personal and relational concerns in that these 2 important needs cannot always be gratified simultaneously. The authors proposed that the experience of personal–relational disequilibrium motivates attempts to restore equilibrium and that achieving equilibrium promotes life satisfaction. Four studies revealed good support for the model.

Madoka Kumashiro; Caryl E. Rusbult; Eli J. Finkel

2008-01-01

343

Non-equilibrium Luttinger liquids Alexander D. Mirlin  

E-print Network

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

Fominov, Yakov

344

EQUILIBRIUM AND FLUX SURFACE ISSUES IN THE DESIGN OF NCSX  

E-print Network

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

Hudson, Stuart

345

5 Thermodynamics 5.1 Deviations from Equilibrium  

E-print Network

5 Thermodynamics 5.1 Deviations from Equilibrium Equilibrium is said to exist in a system when consequence. It is more appropriate to refer to the state of metastable equilibrium, which represents a local metastable equilibria are exactly identi- cal to those dealing with equilibrium so this procedure has

Cambridge, University of

346

On Equilibrium Pricing as Convex Optimization Jiawei Zhang  

E-print Network

On Equilibrium Pricing as Convex Optimization Lihua Chen Yinyu Ye Jiawei Zhang Abstract We study competitive economy equilibrium computation. We show that, for the first time, the equilibrium sets-homogeneous utility functions; are convex or log-convex. Furthermore, an equilibrium can be computed as convex

Ye, Yinyu

347

Isodynamic axisymmetric equilibrium near the magnetic axis  

SciTech Connect

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)

Arsenin, V. V., E-mail: arsenin@nfi.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation)

2013-08-15

348

Equilibrium stellar systems with genetic algorithms  

NASA Astrophysics Data System (ADS)

In 1979, M Schwarzschild showed that it is possible to build an equilibrium triaxial stellar system. However, the linear programmation used to that goal was not able to determine the uniqueness of the solution, nor even if that solution was the optimum one. Genetic algorithms are ideal tools to find a solution to this problem. In this work, we use a genetic algorithm to reproduce an equilibrium spherical stellar system from a suitable set of predefined orbits, obtaining the best solution attainable with the provided set. FULL TEXT IN SPANISH

Gularte, E.; Carpintero, D. D.

349

Combined equilibrium and non-equilibrium phosphorus segregation to grain boundaries in a 2.25Cr1Mo steel  

Microsoft Academic Search

Grain boundary segregation of phosphorus in a P-doped 2.25Cr1Mo steel during ageing at 540 °C after quenching from 980 °C is examined by Auger electron spectroscopy. The segregation is a combined effect of equilibrium segregation and non-equilibrium segregation. The effect of phosphorus non-equilibrium segregation is to enhance the kinetics of its equilibrium segregation.

S.-H. Song; D.-D. Shen; Z.-X. Yuan; J. Liu; T.-D. Xu; L.-Q. Weng

2003-01-01

350

Equilibrium (a), (b) and para-equilibrium (c), (d) phase diagrams for the two steels received from POSCO  

E-print Network

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

Cambridge, University of

351

Equilibrium and Non-equilibrium Kinetics of Self-Assembled Surfactant Monolayers: A Vibrational Sum-Frequency Study of  

E-print Network

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

Richmond, Geraldine L.

352

Folding model study of the charge-exchange scattering to the isobaric analog state and implication for the nuclear symmetry energy  

NASA Astrophysics Data System (ADS)

The Fermi transition ( and between the nuclear isobaric analog states (IAS), induced by the charge-exchange ( p, n) or ( 3He , t reaction, can be considered as "elastic" scattering of proton or 3He by the isovector term of the optical potential (OP) that flips the projectile isospin. The accurately measured ( p, n) or ( 3He , t scattering cross section to the IAS can be used, therefore, to probe the isospin dependence of the proton or 3He optical potential. Within the folding model, the isovector part of the OP is determined exclusively by the neutron-proton difference in the nuclear densities and the isospin dependence of the effective nucleon-nucleon (NN) interaction. Because the isovector coupling explicitly links the isovector part of the proton or 3He optical potential to the cross section of the charge-exchange ( p, n) or ( 3He , t scattering to the IAS, the isospin dependence of the effective (in-medium) NN interaction can be well tested in the folding model analysis of these charge-exchange reactions. On the other hand, the same isospin- and density-dependent NN interaction can also be used in a Hartree-Fock calculation of asymmetric nuclear matter, to estimate the nuclear matter energy and its asymmetry part (the nuclear symmetry energy). As a result, the fine-tuning of the isospin dependence of the effective NN interaction against the measured ( p, n) or ( 3He , t cross sections should allow us to make some realistic prediction of the nuclear symmetry energy and its density dependence.

Khoa, Dao T.; Loc, Bui Minh; Thang, Dang Ngoc

2014-02-01

353

Equation of state of a dense plasma by orbital-free and quantum molecular dynamics: Examination of two isothermal-isobaric mixing rules  

NASA Astrophysics Data System (ADS)

We test two isothermal-isobaric mixing rules, respectively based on excess-pressure and total-pressure equilibration, applied to the equation of state of a dense plasma. While the equation of state is generally known for pure species, that of arbitrary mixtures is not available so that the validation of accurate mixing rules, that implies resorting to first-principles simulations, is very useful. Here we consider the case of a plastic with composition C2H3 and we implement two complementary ab initio approaches adapted to the dense plasma domain: quantum molecular dynamics, limited to low temperature by its computational cost, and orbital-free molecular dynamics, that can be implemented at high temperature. The temperature and density range considered is 1-10 eV and 0.6-10 g/cm 3 for quantum molecular dynamics, and 5-1000 eV and 1-10 g/cm 3 for orbital-free molecular dynamics. Simulations for the full C2H3 mixture are the benchmark against which to assess the mixing rules, and both pressure and internal energy are compared. We find that the mixing rule based on excess-pressure equilibration is overall more accurate than that based on total-pressure equilibration; except for quantum molecular dynamics and a thermodynamic domain characterized by very low or negative excess pressures, it gives pressures which are generally within statistical error or within 1% of the exact ones. Besides, its superiority is amplified in the calculation of a principal Hugoniot.

Danel, J.-F.; Kazandjian, L.

2015-01-01

354

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)

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.

Luckhurst, Geoffrey R.; Satoh, Katsuhiko

2010-05-01

355

Equilibrium and off-equilibrium trap-size scaling in one-dimensional ultracold bosonic gases  

SciTech Connect

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.

Campostrini, Massimo; Vicari, Ettore [Dipartimento di Fisica dell'Universita di Pisa and Instituto Nazionale di Fisica Nucleare, Sezione di Pisa, Largo Bruno Pontecorvo 2, I-56127 Pisa (Italy)

2010-12-15

356

Problems on Non-Equilibrium Statistical Physics  

E-print Network

Four problems in non-equilibrium statistical physics are investigated: 1. The thermodynamics of single-photon gas; 2. Energy of the ground state in Multi-electron atoms; 3. Energy state of the H2 molecule; and 4. The Condensation behavior in N...

Kim, Moochan

2011-08-08

357

Contemporary Mathematics Nonlinear Input-Output Equilibrium  

E-print Network

and study Nonlinear Input-Output Equilibrium (NIOE). The main difference between NIOE and the classical of productive sectors of an economy. Since WW2 the IO model has been widely used for analysis of economic. The applications of IO range from a branch of a single economy to the World economy. The main contributor to IO

Polyak, Roman A.

358

Non Equilibrium Quantum Criticality: an intuitive approach  

NASA Astrophysics Data System (ADS)

Since their discovery in 1976, equilibrium quantum critical points have attracted continuous interest, due to their universality (i.e. the independence from the microscopic details of the systems). In two recent papers [1,2] we have extended these concepts to non-equilibrium systems, by studying the universal properties of quantum systems driven by time-dependent noise. We were able to demonstrated that [1] they can show a new class of non-equilibrium quantum criticality, and [2] small perturbations around the critical point lead to new physical phenomena, such as the spontaneous generation of an effective temperature and an effective dissipation. To this end, we developed a real-time renormalization group (RG) in the Keldysh path-integral formalism, which may however appear cryptic to the non-experts. In this talk, I will show how the main conclusions of the RG approach can be understood by simpler arguments based on circuit theory and fluctuation-dissipation relations. [4pt] [1] E.G. Dalla Torre, et al. ``Quantum critical states and phase transitions in the presence of non-equilibrium noise,'' Nature Physics 6, 806 (2010) [0pt] [2] E.G. Dalla Torre, et al. ``Dynamics and universality in noise driven dissipative systems,'' arXiv: 1110.3678 (2011)

Dalla Torre, Emanuele; Demler, Eugene; Giamarchi, Thierry; Altman, Ehud

2012-02-01

359

Recency, consistent learning, and Nash equilibrium.  

PubMed

We examine the long-term implication of two models of learning with recency bias: recursive weights and limited memory. We show that both models generate similar beliefs and that both have a weighted universal consistency property. Using the limited-memory model we produce learning procedures that both are weighted universally consistent and converge with probability one to strict Nash equilibrium. PMID:25024197

Fudenberg, Drew; Levine, David K

2014-07-22

360

Swelling equilibrium studies of elastomeric network structures  

Microsoft Academic Search

Until recently, interpretation of swelling equilibrium experiments rested on the Flory-Rehner equation developed in 1943 for networks which deform affinely. The relationship made possible at least the ranking of series of networks of the same polymer, according to their cross-link densities. However, the theory does not explain the important fact (first observed by Gee in 1965) that there is a

J. P. Queslel; J. E. Mark

361

Week12: Chapter 12 Static Equilibrium  

E-print Network

in the free body diagram Apply the two conditions of equilibrium to obtain three equations Solve Example, 2 Analyze Draw a free body diagram Use the pivot in the problem (at the wall) as the pivot and the ground Ladder Example, 2 Analyze Draw a free body diagram for the ladder The frictional force

362

Comparing solution methods for dynamic equilibrium economies  

Microsoft Academic Search

This paper compares solution methods for dynamic equilibrium economies. The authors compute and simulate the stochastic neoclassical growth model with leisure choice using Undetermined Coefficients in levels and in logs, Finite Elements, Chebyshev Polynomials, Second and Fifth Order Perturbations and Value Function Iteration for several calibrations. The authors document the performance of the methods in terms of computing time, implementation

S. Boragan Aruoba; Jesus Fernandez-Villaverde; Juan Francisco Rubio-Ramirez

2003-01-01

363

Stochastic interacting particle systems out of equilibrium  

Microsoft Academic Search

This paper provides an introduction to some stochastic models of lattice gases out of equilibrium and a discussion of results of various kinds obtained in recent years. Although these models are different in their microscopic features, a unified picture is emerging at the macroscopic level, applicable, in our view, to real phenomena where diffusion is the dominating physical mechanism. We

L. Bertini; A. DeSole; D. Gabrielli; G. Jona-Lasinio; C. Landim

2007-01-01

364

Spontaneity and Equilibrium II: Multireaction Systems  

ERIC Educational Resources Information Center

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…

Raff, Lionel M.

2014-01-01

365

Role of the Laboratory: Static Equilibrium  

NSDL National Science Digital Library

This activity from the PTRA Manual "The Role of the Laboratory in Teaching Introductory Physics" is a variation of the typical static laboratory activity, and includes a method of measuring buoyant force. See article "Static Equilibrium", by Jim Nelson in the December, 1985 issue of The Science Teacher.

Nelson, Jim; Nelson, Jane

2006-06-18

366

Recency, consistent learning, and Nash equilibrium  

PubMed Central

We examine the long-term implication of two models of learning with recency bias: recursive weights and limited memory. We show that both models generate similar beliefs and that both have a weighted universal consistency property. Using the limited-memory model we produce learning procedures that both are weighted universally consistent and converge with probability one to strict Nash equilibrium. PMID:25024197

Fudenberg, Drew; Levine, David K.

2014-01-01

367

General Equilibrium Models: Improving the Microeconomics Classroom  

ERIC Educational Resources Information Center

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…

Nicholson, Walter; Westhoff, Frank

2009-01-01

368

PUBLISHED VERSION Edge equilibrium code for tokamaks  

E-print Network

a gap in coverage of equilibrium problems by the existing codes. Simulations of the high temperature toka- mak plasma, which outstanding anisotropy increases with the increase in the plasma temperature in adaptive solvers were understood long time ago14­21 and led to creation of POLAR (2-dimensional) and VMEC

369

Lumpy investment in sticky information general equilibrium  

Microsoft Academic Search

This paper introduces lumpy micro-level investment into a sticky information general equilibrium model. Lumpy investment arises because of inattentiveness in capital investment decisions instead of the more popular assumption of non-convex adjustment costs. Sticky information is the only source of rigidity in the model and it is pervasive to all markets and decisions. The model yields aggregate dynamics that are

Fabio Verona

2011-01-01

370

Assessing Students' Conceptual Understanding of Solubility Equilibrium.  

ERIC Educational Resources Information Center

Presents a problem on solubility equilibrium which involves macroscopic, microscopic, and symbolic levels of representation as a resource for the evaluation of students, and allows for assessment as to whether students have acquired an adequate conceptual understanding of the phenomenon. Also diagnoses difficulties with regard to previous…

Raviolo, Andres

2001-01-01

371

Inflation Risk and Capital Market Equilibrium  

Microsoft Academic Search

This paper investigates the effect of inflation uncertainty on the portfolio behavior of households and the equilibrium structure of capitol market rates. The principal findings regarding portfolio behavior are: (1.) In the presence of inflation uncertainty, households will have an inflation-hedging demand for assets other than riskless nominal bonds, which will be directly proportional to the covariance between the rate

Zvi Bodie; C. Merton

1982-01-01

372

Equilibrium : CommonIonEffect (9 Variations)  

NSDL National Science Digital Library

The molar solubility of lead(II) fluoride (PbF 2 ) is 2.1 x 10 -3 mol/L in pure water at 25 o C. What is the molar solubility of lead(II) fluoride in 0.10 M NaF at 25 o C? (Assume that the only relevant reaction is the solubility-product equilibrium.)

373

On the equilibrium of rotating filaments  

NASA Astrophysics Data System (ADS)

The physical properties of the so-called Ostriker isothermal, non-rotating filament have been classically used as benchmark to interpret the stability of the filaments observed in nearby clouds. However, such static picture seems to contrast with the more dynamical state observed in different filaments. In order to explore the physical conditions of filaments under realistic conditions, in this work we theoretically investigate how the equilibrium structure of a filament changes in a rotating configuration. To do so, we solve the hydrostatic equilibrium equation assuming both uniform and differential rotations independently. We obtain a new set of equilibrium solutions for rotating and pressure truncated filaments. These new equilibrium solutions are found to present both radial and projected column density profiles shallower than their Ostriker-like counterparts. Moreover, and for rotational periods similar to those found in the observations, the centrifugal forces present in these filaments are also able to sustain large amounts of mass (larger than the mass attained by the Ostriker filament) without being necessary unstable. Our results indicate that further analysis on the physical state of star-forming filaments should take into account rotational effects as stabilizing agents against gravity.

Recchi, S.; Hacar, A.; Palestini, A.

2014-10-01

374

Bimatrix Equilibrium Points and Mathematical Programming  

Microsoft Academic Search

Some simple constructive proofs are given of solutions to the matric system Mz - \\\\omega - q; z \\\\geqq 0; \\\\omega \\\\geqq 0; and zT<\\/sup> \\\\omega - 0, for various kinds of data M, q, which embrace the quadratic programming problem and the problem of finding equilibrium points of bimatrix games. The general scheme is, assuming non-degeneracy, to generate an

C. E. Lemke

1965-01-01

375

Integration Versus Outsourcing In Industry Equilibrium  

Microsoft Academic Search

We develop an equilibrium model of industrial structure in which the organization of firms is endogenous. Differentiated consumer products can be produced either by vertically integrated firms or by pairs of specialized companies. Production of each variety of consumer good requires a specialized component. Vertically integrated firms can manufacture the components they need, but they face a relatively high cost

Gene M. Grossman; Elhanan Helpman

2002-01-01

376

Teaching Chemical Equilibrium with the Jigsaw Technique  

ERIC Educational Resources Information Center

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…

Doymus, Kemal

2008-01-01

377

The 'Schwarzschild-Kerr' Equilibrium Configurations  

SciTech Connect

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.

Manko, V. S. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico); Ruiz, E. [Instituto Universitario de Fisica Fundamental y Matematicas, Universidad de Salamanca, 37008 Salamanca (Spain)

2010-12-07

378

Poverty Analysis Within a General Equilibrium Framework  

Microsoft Academic Search

The main objective of this paper is to show how Social Accounting Matrices (SAM) and Computable General Equilibrium (CGE) Models can be used to highlight and address issues related to income distribution and poverty. The paper is divided into two major parts. Part 1 presents the concept of the SAM as a comprehensive, consistent and disaggregated data system and shows

B. Decaluwe; A. Patry; L. Savard; E. Thorbecke

1999-01-01

379

Effective equilibrium theory of nonequilibrium quantum transport  

SciTech Connect

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.

Dutt, Prasenjit [Department of Physics, Yale University, New Haven, CT 06520 (United States); Koch, Jens [Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Han, Jong [Department of Physics, State University of New York at Buffalo, Buffalo, NY 14260 (United States); Le Hur, Karyn, E-mail: karyn.lehur@yale.edu [Department of Physics, Yale University, New Haven, CT 06520 (United States)

2011-12-15

380

Chemical equilibrium and non-equilibrium inviscid flow simulations using an explicit scheme  

NASA Astrophysics Data System (ADS)

Within the framework of the collaboration between IMHEF-Lausanne and CERFACS-Toulouse, a 2D/axisymmetric Euler solver for hypersonic flows has been developed. The Euler equations are solved using a space centered scheme augmented by artificial dissipation terms. The time integration is carried out using an explicit Runge-Kutta scheme. Three different methods to account for the effects of equilibrium air chemistry have been incorporated and are compared. Non-equilibrium chemistry has been implemented using two different numerical approaches. Calculations showed that equilibrium air simulations using the model of Park were only 9% more expensive than caloric perfect gas simulations. Chemical non-equilibrium computations showed that the air chemistry, for the initial conditions used, was not "stiff", and could be resolved using a simple explicit scheme. No special treatment of the chemical source term was hereby required.

Vos, J. B.; Bergman, C. M.

1991-04-01

381

Non-Equilibrium Heavy Flavored Hadron Yields from Chemical Equilibrium Strangeness-Rich QGP  

E-print Network

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.

Inga Kuznetsova; Johann Rafelski

2008-01-05

382

Equilibrium and non-equilibrium phase transitions in copolymer polyelectrolyte hydrogels  

NASA Astrophysics Data System (ADS)

A continuum model of polyelectrolyte hydrogel phase transitions has been developed and used to analyze the equilibrium and non-equilibrium swelling transitions observed in copolymer N-isopropylacrylamide (NIPA), acrylic acid (AAc), and acrylamide (AAm) hydrogels. The contribution of the dominant forces to the overall swelling response has been illustrated experimentally by systematically varying both the hydrogel and bath composition. We have interpreted the equilibrium swelling pattern theoretically by separately examining the role of charge, acid dissociation, and solvent mediated effects. The non-equilibrium swelling response to changes in bath ionic strength has been examined in terms of competing coupled ion, diffusion reaction, polymer network mechanisms, and the potential role of film boundary effects. We have obtained qualitative agreement between our theory and measurements and have critically examined both the strengths and limitations of our model.

English, Anthony E.; Tanaka, Toyoichi; Edelman, Elazer R.

1997-08-01

383

Cosmic curvature from de Sitter equilibrium cosmology.  

PubMed

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

Albrecht, Andreas

2011-10-01

384

Instability of quantum equilibrium in Bohm's dynamics.  

PubMed

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

Colin, Samuel; Valentini, Antony

2014-11-01

385

Uncertainty Principle Consequences at Thermal Equilibrium  

E-print Network

Contrary to the conventional wisdom that deviations from standard thermodynamics originate from the strong coupling to the bath, it is shown that these deviations are intimately linked to the power spectrum of the thermal bath. Specifically, it is shown that the lower bound of the dispersion of the total energy of the system, imposed by the uncertainty principle, is dominated by the bath power spectrum and therefore, quantum mechanics inhibits the system thermal-equilibrium-state from being described by the canonical Boltzmann's distribution. This is in sharp contrast to the classical case, for which the thermal equilibrium distribution of a system interacting via central forces with pairwise-self-interacting environment, irrespective of the interaction strength, is shown to be \\emph{exactly} characterized by the canonical Boltzmann distribution. As a consequence of this analysis, we define an \\emph{effective coupling} to the environment that depends on all energy scales in the system and reservoir interactio...

Pachon, Leonardo A; Zueco, David; Brumer, Paul

2014-01-01

386

Nonequilibrium fluctuation theorems from equilibrium fluctuations  

NASA Astrophysics Data System (ADS)

A system can be driven to nonequilibrium behavior in the presence of thermodynamic imbalances in its environment, such as temperature or chemical potential differences. In derivations of far-from-equilibrium fluctuation theorems, such imbalances are typically modeled as fixed, externally imposed thermodynamic forces. Here, we argue that fluctuation theorems can instead be understood in terms of the equilibrium dynamics of a larger supersystem, containing both the system of interest and its thermal surroundings. To this end, we consider rare fluctuations that spontaneously produce imbalances in the surroundings. In the aftermath of such fluctuations, the system of interest transiently behaves as though it were in the presence of an externally applied thermodynamic force. By applying the principle of detailed balance to these rare events, we recover the fluctuation theorem in both its transient and steady-state formulations.

Rahav, Saar; Jarzynski, Christopher

2013-12-01

387

Equilibrium statistical mechanics for incomplete nonextensive statistics  

E-print Network

The incomplete nonextensive statistics in the canonical and microcanonical ensembles is explored in the general case and in a particular case for the ideal gas. By exact analytical results for the ideal gas it is shown that taking the thermodynamic limit, with $z=q/(1-q)$ being an extensive variable of state, the incomplete nonextensive statistics satisfies the requirements of equilibrium thermodynamics. The thermodynamical potential of the statistical ensemble is a homogeneous function of the first degree of the extensive variables of state. In this case, the incomplete nonextensive statistics is equivalent to the usual Tsallis statistics. If $z$ is an intensive variable of state, i.e. the entropic index $q$ is a universal constant, the requirements of the equilibrium thermodynamics are violated.

A. S. Parvan; T. S. Biro

2010-03-29

388

Phase Equilibrium Investigations of Planetary Materials  

NASA Technical Reports Server (NTRS)

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.

Grove, T. L.

2005-01-01

389

Quasi-Equilibrium in Epitaxial Growth  

Microsoft Academic Search

We have produced a square geometry solid-on-solid (SOS) kinetic Monte Carlo model to investigate the presence of a low coverage quasi-equilibrium regime during epitaxial growth. The SOS model is a restricted pair-bond model wherein atoms on the surface with one in-plane nearest neighbor are allowed to detach from island edge positions with a rate, r1. Thus, the simulation is applicable

M. Gahl; E. Gust; A. Saxton; K. R. Roos

2003-01-01

390

Introduction to Equilibrium Thermodynamics: Salt Dissolution  

NSDL National Science Digital Library

In this lab I simply have students dissolve halite and sylvite in water at various temperatures. I use this experiment to introduce students to the principles of equilibrium thermodynamics, as well as basic lab skills, data analysis, and lab report writing. Students use basic laboratory skills to conduct their experiments then analyze their data using a spreadsheet program such as Excel. They then write up their results and discussion in a formal lab report.

Knudsen, Andrew

391

Quasilocal equilibrium condition for black ring  

E-print Network

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.

Dumitru Astefanesei; Maria J. Rodriguez; Stefan Theisen

2010-04-25

392

Power-law tailed spectra from equilibrium  

E-print Network

We propose that power-law tailed hadron spectra may be viewed as stemming from a matter in an unconventional equilibrium state typical for non-extensive thermodynamics. A non-extensive Boltzmann equation, which is able to form such spectra as a stationary solution, is utilized as a rough model of quark matter hadronization. Basic ideas about non-extensive simulation of the QCD equation of state on the lattice are presented.

T. S. Biro; G. Purcsel; G. Gyorgyi; A. Jakovac; Zs. Schram

2005-10-03

393

The Multiple Equilibrium Model of Micelle Formation  

Microsoft Academic Search

In dilute aqueous solution surface-active molecules aggregate to form micelles. This process has been described by a multiple equilibrium model which considers changes in the distribution of micelle aggregation numbers with concentration. Analysis of the colligative properties of dilute aqueous solutions of non-ionic surface-active agents has enabled the concentration of monomer to be determined as a function of the total

J. M. Corkill; J. F. Goodman; T. Walker; J. Wyer

1969-01-01

394

The equilibrium boundary between grahite and diamond  

Microsoft Academic Search

The equilibrium boundary between diamond and graphite has been determined over the temperature interval 1100°C-1625°C. A piston-cylinder apparatus and a ''zero-friction'' cell were used. Pressures were computed by force\\/area measurements and are independent of any calibration points. Visual observations of diamond dissolution or diamond growth were used in fixing the position of the boundary. Our newly determined boundary has the

C. Scott Kennedy; George C. Kennedy

1976-01-01

395

Out-of-equilibrium electromagnetic radiation  

E-print Network

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.

Julien Serreau

2004-06-22

396

Bifurcated helical core equilibrium states in tokamaks  

NASA Astrophysics Data System (ADS)

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.

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

397

Statistical approach to partial equilibrium analysis  

NASA Astrophysics Data System (ADS)

A statistical approach to market equilibrium and efficiency analysis is proposed in this paper. One factor that governs the exchange decisions of traders in a market, named willingness price, is highlighted and constitutes the whole theory. The supply and demand functions are formulated as the distributions of corresponding willing exchange over the willingness price. The laws of supply and demand can be derived directly from these distributions. The characteristics of excess demand function are analyzed and the necessary conditions for the existence and uniqueness of equilibrium point of the market are specified. The rationing rates of buyers and sellers are introduced to describe the ratio of realized exchange to willing exchange, and their dependence on the market price is studied in the cases of shortage and surplus. The realized market surplus, which is the criterion of market efficiency, can be written as a function of the distributions of willing exchange and the rationing rates. With this approach we can strictly prove that a market is efficient in the state of equilibrium.

Wang, Yougui; Stanley, H. E.

2009-04-01

398

Equilibrium Columnar Structure of Magnetorheological Fluid  

NASA Astrophysics Data System (ADS)

The equilibrium structure of magnetorheological (MR) fluid at low volume fraction and large magnetic field is known to consist of tapered columns of magnetized particles, in a roughly hexagonal array. Experimental evidence at large field indicates that the distance between nearest-neighbor columns, d, scales with sample thickness L as d ~ L^?, with ? about 1/3 for L less than about 200 particle diameters and 1/2 for thicker samples. Numerical simulations would require of the order of 10^6 degrees of freedom to reproduce these experimental results. As an alternative, a 2-d model is introduced which treats columns as bundles of uniform chains of dipolar particles. This allows semi-numerical investigation of equilibrium patterns at large magnetic field (? arrow ?). Equilibrium configurations are accessed through simulated annealing, as a function of L. Results neglecting tapering reproduce d ~ L^?, with an exponent between 1/3 and 1/2, for all L considered. The minimum energy columns turn out to be crystalline, with a roughly square cross section. The binding energy per particle grows as ln L for L less than about 100 particle diameters. The important effect of tapering is taken into account by allowing the chains which form a column to have variable lengths. Further results including effects of tapering and internal structure will be presented.

Gross, Mark

1998-03-01

399

Quasi-equilibrium in tapered chains  

NASA Astrophysics Data System (ADS)

The approach to equilibrium in 1d lattices is interesting for granular media since temperature is not well-defined and various authors have reported a violation of equipartition. We extend our previous work on shock mitigation in tapered chains to look at energy sharing among spheres and how the system appraoches a so-called quasi-equilibrium. An overlap potential of adjacent particles is used to model the elastic response of spheres under loading and has the form, V˜ncirc. For spheres, n=5/2 and is known as the Hertz potential. We can also compare results when n=2 which resembles spring-like behavior. It should be noted however, that in both cases the potential has no restoration term and vanishes when adjacent spheres lose contact. We present the velocity statistics for a variety of Hertzian chain configurations as well as fluctuations for the system's total kinetic energy for both n=2 and n=2.5. We find that most particles in these systems exhibit Gaussian velocity distributions and that the kinetic energy fluctuations of the system depend strongly on system size and weakly on tapering of the spheres. Fluctuations do not damp out over long time however, indicating that the steady-state is a type of quasi-equilibrium. Mathematical fits of the mean fluctuations are further provided as functions of system size, tapering, and n.

Doney, Robert; Sen, Surajit

2007-03-01

400

Toward a Global Magnetospheric Equilibrium Model  

NASA Astrophysics Data System (ADS)

A ``quasi-static" equilibrium between magnetic (Lorentz) forces and plasma pressure gradient forces exists at most times in the magnetosphere, except for periods of explosive activity such as substorms. The magnetospheric evolution is thus slow enough so that it can be portrayed as a time sequence of such equilibria. In order to model quasi-static equilibria, we have started the development of a comprehensive three-dimensional self-consistent model of the magnetosphere, by coupling a 3-D equilibrium code in flux coordinates [Cheng, 1995, Zaharia et al., 2004] covering the inner/middle magnetosphere with an asymptotic ``tail equilibrium" model [Birn, 1987]. The coupling project is facilitated by the similar magnetic field representation, in terms of Euler potentials, in both models. We will present initial results from this effort, focusing on global configurations (including both closed- and open-field regions) obtained by coupling the two models for particular cases, such as north-south symmetry and 2-D geometry. We will discuss the results obtained by using different coupling procedures, boundary conditions and input pressure functions. Presenting computed sequences of quasi-static equilibria, we will also discuss how the magnetosphere evolves under changing external (solar wind) conditions, modeled by changes in magnetic flux boundaries and pressure profiles. In particular, we will discuss the possibility for appearance of thin cross-tail current sheets under boundary deformations.

Zaharia, S. G.; Birn, J.; Cheng, C. Z.

2004-12-01

401

Recovery of postural equilibrium control following spaceflight  

NASA Technical Reports Server (NTRS)

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.

Paloski, W. H.; Reschke, M. F.; Black, F. O.; Doxey, D. D.; Harm, D. L.

1992-01-01

402

Radioactive equilibrium in ancient marine sediments  

USGS Publications Warehouse

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.

Breger, I.A.

1955-01-01

403

Analytical Ultracentrifugation: Sedimentation Velocity and Sedimentation Equilibrium  

PubMed Central

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

Cole, James L.; Lary, Jeffrey W.; Moody, Thomas; Laue, Thomas M.

2009-01-01

404

Hamiltonian approach to the magnetostatic equilibrium problem  

SciTech Connect

The purpose of this paper is to investigate the classical scalar-pressure magnetostatic equilibrium problem for non-symmetric configurations in the framework of a Hamiltonian approach. Requiring that the equilibrium admits locally, in a suitable subdomain, a family of nested toroidal magnetic surfaces, the Hamiltonian equations describing the magnetic flux lines in such a subdomain are obtained for general curvilinear coordinate systems. The properties of such Hamiltonian system are investigated. A representation of the magnetic field in terms of arbitrary general curvilinear coordinates is thus obtained. Its basic feature is that the magnetic field must fulfill suitable periodicity constraints to be imposed on arbitrary rational magnetic surfaces for general non-symmetric toroidal equilibria, i.e., it is quasi-symmetric. Implications for the existence of magnetostatic equilibria are pointed out. In particular, it is proven that a generalized equilibrium equation exists for such quasi-symmetric equilibria, which extends the Grad-Shafranov equation to fully three-dimensional configurations. As an application, the case is considered of quasi-helical equilibria, i.e., displaying a magnetic field magnitude depending on the poloidal ({chi}) and toroidal ({var_theta}) angles only in terms of {alpha}={chi}-N{theta} with N an arbitrary integer.

Tessarotto, M.; Zheng, Lin Jin [Universita di Trieste (Italy); Johnson, J.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.

1995-02-01

405

On the Equilibrium States of Interconnected Bubbles or Balloons.  

ERIC Educational Resources Information Center

Describes the equilibrium states of a system composed of two interconnected, air-filled spherical membranes of different sizes. The equilibrium configurations are determined by the method of minimization of the availability of the system at constant temperature. (GA)

Weinhaus, F.; Barker, W.

1978-01-01

406

Fluctuation-induced phenomena in non-equilibrium systems  

E-print Network

In this thesis, we investigate the implications of fluctuations in systems away, possibly even far, from equilibrium due to their motion either in or out of thermal equilibrium. This subject encompasses several topics in ...

Faghfoor M., Mohammad (Faghfoor Maghrebi)

2013-01-01

407

Fractal Geometry of Equilibrium Payoffs in Discounted Supergames  

NASA Astrophysics Data System (ADS)

This paper examines the pure-strategy subgame-perfect equilibrium payoffs in discounted supergames with perfect monitoring. It is shown that the equilibrium payoffs can be identified as sub-self-affine sets or graph-directed iterated function systems. We propose a method to estimate the Hausdorff dimension of the equilibrium payoffs and relate it to the equilibrium paths and their graph presentation.

Berg, Kimmo; Kitti, Mitri

2014-08-01

408

MARKETS FOR TRANSMISSION RIGHTS: A COMPETITIVE EQUILIBRIUM MODEL  

Microsoft Academic Search

In this paper, competitive equilibrium models of markets for Financial Transmission Rights (FTRs) are presented. An FTRs market is modelled by using a set of market-equilibrium conditions for every entity that participate in the transmission market. The proposed equilibrium framework is more natural and e xible for modelling markets than the classic cost-minimization auction. Different markets for Financial Transmission Rights

Guillermo Bautista; Victor H. Quintana; Jose A. Aguadoyy

409

CLOSED-FORM EQUILIBRIUM ANALYSIS OF A PLANAR TENSEGRITY STRUCTURE  

E-print Network

CLOSED-FORM EQUILIBRIUM ANALYSIS OF A PLANAR TENSEGRITY STRUCTURE Jahan Bayat University of Florida a closed-form analysis of a two-spring planar tensegrity mechanism to determine all possible equilibrium in the spring length is zero. A numerical example is presented. Keywords: Tensegrity, compliance, equilibrium. 1

Florida, University of

410

http://w3.pppl.gov/~zakharov Equilibrium  

E-print Network

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

Zakharov, Leonid E.

411

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

412

A NON-EQUILIBRIUM ANALYSIS & CONTROL FRAMEWORK FOR COMMUNICATION NETWORKS  

E-print Network

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

Alpcan, Tansu

413

Equilibrium of highly asymmetric non-neutral plasmas J. Fajansa)  

E-print Network

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

Fajans, Joel

414

The Equilibrium Point Hypothesis for Control of Movements Reza Shadmehr  

E-print Network

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

Shadmehr, Reza

415

Equilibrium management of fisheries with altruistic overlapping generations  

E-print Network

Equilibrium management of fisheries with altruistic overlapping generations Ivar Ekeland Larry Karp rates, leading to time inconsistency. The unique Markov Perfect equilibrium to this model has a striking feature: provided that the current generation has some concern for the not-yet born, the equilibrium

Kammen, Daniel M.

416

Non-equilibrium Chemistry in Brown Dwarf Atmospheres  

E-print Network

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

Metchev, Stanimir

417

Hanging an Airplane: A Case Study in Static Equilibrium  

ERIC Educational Resources Information Center

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…

Katz, Debora M.

2009-01-01

418

http://w3.pppl.gov/~zakharov equilibrium  

E-print Network

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

Zakharov, Leonid E.

419

EQUILIBRIUM PATHS OF MECHANICAL SYSTEMS WITH UNILATERAL CONSTRAINTS  

E-print Network

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

Pellegrino, Sergio

420

Equilibrium shape degeneracy in starfish vesicles Xavier Michalet*  

E-print Network

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

Michalet, Xavier

421

Unified Electroanalytical Chemistry: Application of the Concept of Electrochemical Equilibrium  

Microsoft Academic Search

Electroanalytical chemistry, encompassing both static and dynamic techniques, can be unified and best explained by invoking the concept of electrochemical equilibrium. Parallel to chemical equilibrium that occurs when -TDStot = DG = 0, electrochemical equilibrium is established when -TDStot = {DG + DUel} = 0; that is, when the tendency to pump electrons from the electrical subsystem is exactly counterbalanced

Robert Q. Thompson; Norman C. Craig

2001-01-01

422

Non-Equilibrium Fluctuation-Dissipation Inequality and Non-Equilibrium Uncertainty Principle  

E-print Network

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.

C. H. Fleming; B. L. Hu; Albert Roura

2010-12-03

423

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

424

Multicomponent Equilibrium Models for Testing Geothermometry Approaches  

SciTech Connect

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.

Cooper, D. Craig; Carl D. Palmer; Robert W. Smith; Travis L. McLing

2013-02-01

425

Equilibrium of nucleotides in the dogfish brain.  

PubMed

In the past, the results of experiments on the time course of concentration changes of adenylates, phosphocreatine, and free creatine in muscle appeared compatible with an equilibrium hypothesis involving only the Lohmann and the myokinase reactions. Other reports, however, denied the applicability of the equilibrium hypothesis to the same tissue. The controversy may have been due to the high probability of experimental errors since time sampling was performed at second intervals. We presently test the hypothesis in the living brain of the small-spotted dogfish shark (Scyliorhinus canicula), an animal-model allowing for timing of sampling at hourly intervals. According to our earlier work, the dogfish shark can easily be resuscitated 8.2 h on average after being brought into the state of "suspended animation" at 0 degree C body temperature and exposed, out of water, to an atmosphere of nitrogen gas. To obtain a complete mathematical description of the time course of concentration changes of brain adenylates and phosphocreatine, we devised a kinetic model based on principles of classical multicompartmental analysis and biochemical kinetics. Model testing of the equilibrium hypothesis resulted in very good agreement between the hypothesis and our experimental data. Time-course modeling, achieved by simultaneously fitting the time series of our data by the set of four equations constituting our model resulted in an excellent agreement between data points and the computed curves. Finally, modeling of the depletion profiles of brain energy status concerning three of its descriptors (energy charge, total adenylate, and primary energy stores expressed in high-energy phosphate equivalents) allowed for a correlation to be established between energy status and the "revival time," a valuable physiological descriptor of tolerance. PMID:16154919

Andjus, Radoslav K; Dzakula, Zeljko; Marjanovi?, Marina

2005-06-01

426

MEMBRANE POTENTIALS IN THE DONNAN EQUILIBRIUM. II  

PubMed Central

Measurements were made of electromotive force in the Donnan equilibrium of systems containing dilute solutions of protein and acid. Removal of the membrane produced a decrease of no more than 2 to 4 mv. in electromotive force, while the membrane potentials, as estimated by the usual arbitrary assumption, were of the order of 12 to 34 mv. Ion ratios, as calculated from analyses for total chloride, were definitely greater than those calculated from the electromotive force of cells with salt bridges, as if there had been combination of some of the chloride ion with protein. PMID:13174778

Hitchcock, David I.

1954-01-01

427

Equilibrium coverage of halides on metal electrodes  

NASA Astrophysics Data System (ADS)

The adsorption of halides on Cu(111) and Pt(111) has been studied using periodic density functional theory calculations. The equilibrium coverage of the halides as a function of the electrode potential was determined using a thermodynamic approach in which the electrochemical environment is not explicitly taken into account. For all considered systems, halide coverages between 1/3 and 3/8 should be stable over a wide potential range. Although some quantitative discrepancies with experiment are obtained, the qualitative trends derived from the calculations are consistent with experimental observations. The reasons for the remaining discrepancies with the experiment are discussed.

Gossenberger, Florian; Roman, Tanglaw; Groß, Axel

2015-01-01

428

Process for operating equilibrium controlled reactions  

DOEpatents

A cyclic process for operating an equilibrium controlled reaction in a plurality of reactors containing an admixture of an adsorbent and a reaction catalyst suitable for performing the desired reaction which is operated in a predetermined timed sequence wherein the heating and cooling requirements in a moving reaction mass transfer zone within each reactor are provided by indirect heat exchange with a fluid capable of phase change at temperatures maintained in each reactor during sorpreaction, depressurization, purging and pressurization steps during each process cycle.

Nataraj, Shankar (Allentown, PA); Carvill, Brian Thomas (Orefield, PA); Hufton, Jeffrey Raymond (Fogelsville, PA); Mayorga, Steven Gerard (Allentown, PA); Gaffney, Thomas Richard (Allentown, PA); Brzozowski, Jeffrey Richard (Bethlehem, PA)

2001-01-01

429

A non-equilibrium quantum Landauer principle  

E-print Network

Using the operational framework of completely positive, trace preserving operations and thermodynamic fluctuation relations, we derive a lower bound for the heat exchange in a Landauer erasure process on a quantum system. Our bound comes from a non-phenomenological derivation of the Landauer principle which holds for generic non-equilibrium dynamics. Furthermore the bound depends on the non-unitality of dynamics, giving it a physical significance that differs from other derivations. We apply our framework to the model of a spin-1/2 system coupled to an interacting spin chain at finite temperature.

John Goold; Mauro Paternostro; Kavan Modi

2015-01-09

430

Natural Equilibrium States for Multimodal Maps  

NASA Astrophysics Data System (ADS)

This paper is devoted to the study of the thermodynamic formalism for a class of real multimodal maps. This class contains, but it is larger than, Collet-Eckmann. For a map in this class, we prove existence and uniqueness of equilibrium states for the geometric potentials - t log | Df|, for the largest possible interval of parameters t. We also study the regularity and convexity properties of the pressure function, completely characterising the first order phase transitions. Results concerning the existence of absolutely continuous invariant measures with respect to the Lebesgue measure are also obtained.

Iommi, Godofredo; Todd, Mike

2010-11-01

431

Control of chemical equilibrium through optical pumping  

NASA Astrophysics Data System (ADS)

Kastler has shown that the equilibrium rate between alkali dimers and atoms can be changed by optical orientation of the unpaired valence electron of the atom. Optical pumping experiments performed in Pisa which prove Kastler considerations are here recalled. Kastler a montré que le taux d'équilibre entre les atomes alcalins et leurs dimères peut être changé par orientation optique de l'électron de valence célibataire de l'atome. Nous rappelons ici des expériences de pompage optique effectuées à Pise qui vérifient les considérations de Kastler.

Allegrini, M.; Alzetta, G.; Bicchi, P.; Gozzini, S.; Moi, L.

432

Modeling Equilibrium Clusters in Lysozyme Solutions  

E-print Network

We present a combined experimental and numerical study of the equilibrium cluster formation in globular protein solutions under no-added salt conditions. We show that a cluster phase emerges as a result of a competition between a long-range screened Coulomb repulsion and a short-range attraction. A simple effective potential, in which only depth and width of the attractive part of the potential are optimized, accounts in a remarkable way for the wavevector dependence of the X-ray scattering structure factor.

Frédéric Cardinaux; Anna Stradner; Peter Schurtenberger; Francesco Sciortino; Emanuela Zaccarelli

2006-08-04

433

Cylindrical equilibrium shapes of fluid membranes  

E-print Network

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.

V. M. Vassilev; P. A. Djondjorov; I. M. Mladenov

2009-10-22

434

The equilibrium dynamics of rotating systems  

NASA Astrophysics Data System (ADS)

Several aspects of the theory of asymptotic equilibrium states and the stability of rotating rigid bodies with elastic attachments are described. Attention is then focused on single degree of freedom rotation of planar kinematic chains in a gravitational field, and for this class of systems it is shown that a number of stable (as well as unstable) steady state motions can occur. A fairly complete description of the dependence of these motions on mechanical parameters of mass, link lengths, and momentum is presented, pointing to a very rich general bifurcation and stability theory of rotating systems.

Baillieul, John

435

Thermal Casimir vs Casimir-Polder forces: Equilibrium and non-equilibrium forces  

E-print Network

We critically discuss the common belief that the thermal Casimir-Polder force can always be represented as a Matsubara sum, as it is true for the Casimir force. On the contrary, an exact treatment of the atom-field coupling reveals that for a ground-state atom, terms associated with virtual-photon absorption contribute to the force which are identified as a signature of non-equilibrium dynamics. Even the equilibrium force on a thermalized atom or molecule may be overestimated when using the ground-state polarizability instead of its thermal counterpart.

Stefan Yoshi Buhmann; Stefan Scheel

2008-08-14

436

Universality in equilibrium and away from it: A personal perspective  

SciTech Connect

In this talk/paper I discuss the concept of universality in phase transitions and the question of whether universality classes are more robust in equilibrium than away from it. In both of these situations, the main ingredients determining universality are symmetries, conservation laws, the dimension of the space and of the order-parameter and the presence of long-range interactions or quenched disorder. The existence of detailed-balance and fluctuation-dissipation theorems imposes severe constraints on equilibrium systems, allowing to define universality classes in a very robust way; instead, non-equilibrium allows for more variability. Still, quite robust non-equilibrium universality classes have been identified in the last decades. Here, I discuss some examples in which (i) non-equilibrium phase transitions are simply controlled by equilibrium critical points, i.e. non-equilibrium ingredients turn out to be irrelevant in the renormalization group sense and (ii) non-equilibrium situations in which equilibrium seems to come out of the blue, generating an adequate effective description of intrinsically non-equilibrium problems. Afterwards, I shall describe different genuinely non-equilibrium phase transitions in which introducing small, apparently innocuous changes (namely: presence or absence of an underlying lattice, parity conservation in the overall number of particles, existence of an un-accessible vacuum state, deterministic versus stochastic microscopic rules, presence or absence of a Fermionic constraint), the critical behavior is altered, making the case for lack of robustness. However, it will be argued that in all these examples, there is an underlying good reason (in terms of general principles) for universality to be altered. The final conclusions are that: (i) robust universality classes exist both in equilibrium and non-equilibrium; (ii) symmetry and conservation principles are crucial in both, (iii) non-equilibrium allows for more variability (i.e. it is less constrained).

Munoz, Miguel A. [Departamento de Electromagnetismo y Fisica de la Materia and Instituto de Fisica Teorica y Computacional Carlos I, Facultad de Ciencias, Campus Fuentenueva. Universidad de Granada, 18071 Granada (Spain)

2011-03-24

437

Structural design using equilibrium programming formulations  

NASA Technical Reports Server (NTRS)

Solutions to increasingly larger structural optimization problems are desired. However, computational resources are strained to meet this need. New methods will be required to solve increasingly larger problems. The present approaches to solving large-scale problems involve approximations for the constraints of structural optimization problems and/or decomposition of the problem into multiple subproblems that can be solved in parallel. An area of game theory, equilibrium programming (also known as noncooperative game theory), can be used to unify these existing approaches from a theoretical point of view (considering the existence and optimality of solutions), and be used as a framework for the development of new methods for solving large-scale optimization problems. Equilibrium programming theory is described, and existing design techniques such as fully stressed design and constraint approximations are shown to fit within its framework. Two new structural design formulations are also derived. The first new formulation is another approximation technique which is a general updating scheme for the sensitivity derivatives of design constraints. The second new formulation uses a substructure-based decomposition of the structure for analysis and sensitivity calculations. Significant computational benefits of the new formulations compared with a conventional method are demonstrated.

Scotti, Stephen J.

1995-01-01

438

The equilibrium model of relationship maintenance.  

PubMed

A new equilibrium model of relationship maintenance is proposed. People can protect relationship bonds by practicing 3 threat-mitigation rules: Trying to accommodate when a partner is hurtful, ensuring mutual dependence, and resisting devaluing a partner who impedes one's personal goals. A longitudinal study of newlyweds revealed evidence for the equilibrium model, such that relationship well-being (as indexed by satisfaction and commitment) declining from its usual state predicted increased threat-mitigation; in turn, increasing threat mitigation from its usual state predicted increased relationship well-being. Longitudinal findings further revealed adaptive advantages to uncertain trust. First, the match between trust and partner-risk predicted the trajectory of threat mitigation over time. People who hesitated to trust a high-risk partner became more likely to mitigate threats over 3 years, but people who hesitated to trust a safe partner became less likely to mitigate threats. The match between threat mitigation and partner-risk also predicted when being less trusting eroded later relationship well-being. Namely, when women paired with high-risk partners became more likely to mitigate threats, being less trusting at marriage lost its capacity to erode later relationship well-being. (PsycINFO Database Record (c) 2015 APA, all rights reserved). PMID:25603369

Murray, Sandra L; Holmes, John G; Griffin, Dale W; Derrick, Jaye L

2015-01-01

439

Equilibrium stellar systems with spindle singularities  

NASA Technical Reports Server (NTRS)

Equilibrium sequences of axisymmetric Newtonian clusters that tend toward singular states are constructed. The distribution functions are chosen to be of the form f = f(E, Jz). The numerical method then determines the density and gravitational potential self-consistently to satisfy Poisson's equation. For the prolate models, spindle singularities arise from the depletion of angular momentum near the symmetry axis. While the resulting density enhancement is confined to the region near the axis, the influence of the spindle extends much further out through its tidal gravitational field. Centrally condensed prolate clusters may contain strong-field regions even though the spindle mass is small and the mean cluster eccentricity is not extreme. While the calculations performed here are entirely Newtonian, the issue of singularities is an important topic in general relativity. Equilibrium solutions for relativistic star clusters can provide a testing ground for exploring this issue. The methods used in this paper for building nonspherical clusters can be extended to relativistic systems.

Shapiro, Stuart L.; Teukolsky, Saul A.

1992-01-01

440

Noncooperative equilibrium for state dependent supergames  

SciTech Connect

This report advances the state of the game modeling art by analyzing a general class of dynamic games in which the actions of each participant influence both immediate and future payoff opportunities of other ''players.'' The author first develops a set of axioms which imply that a noncooperative equilibrium (a set of individually rational and mutually consistent dynamic strategies) exists, so that the model itself is not vacuous. He then shows that cooperation, in the form of undertaking strategies which differ from noncooperative equilibrium choices, is mutually beneficial under certain conditions. While the technical analysis is directed primarily at an audience of specialists in game theory, the paper is useful in both setting out the capabilities of the theory and its limitations. An example concerning development and extraction of common property petroleum reserves illustrates the application of the model to externality situations. The analysis also forms a basis for work underway in the Energy and National Security Project on the dynamics of unilateral and coordinated international energy policymaking. 12 refs.

Toman, M.A.

1982-09-01

441

Uncertainty Principle Consequences at Thermal Equilibrium  

E-print Network

Contrary to the conventional wisdom that deviations from standard thermodynamics originate from the strong coupling to the bath, it is shown that these deviations are intimately linked to the power spectrum of the thermal bath. Specifically, it is shown that the lower bound of the dispersion of the total energy of the system, imposed by the uncertainty principle, is dominated by the bath power spectrum and therefore, quantum mechanics inhibits the system thermal-equilibrium-state from being described by the canonical Boltzmann's distribution. This is in sharp contrast to the classical case, for which the thermal equilibrium distribution of a system interacting via central forces with pairwise-self-interacting environment, irrespective of the interaction strength, is shown to be \\emph{exactly} characterized by the canonical Boltzmann distribution. As a consequence of this analysis, we define an \\emph{effective coupling} to the environment that depends on all energy scales in the system and reservoir interaction. Sample computations in regimes predicted by this effective coupling are demonstrated. For example, for the case of strong effective coupling, deviations from standard thermodynamics are present and, for the case of weak effective coupling, quantum features such as stationary entanglement are possible at high temperatures.

Leonardo A. Pachon; Johan F. Triana; David Zueco; Paul Brumer

2014-01-07

442

Accurate Equilibrium Structures for Piperidine and Cyclohexane.  

PubMed

Extended and improved microwave (MW) measurements are reported for the isotopologues of piperidine. New ground state (GS) rotational constants are fitted to MW transitions with quartic centrifugal distortion constants taken from ab initio calculations. Predicate values for the geometric parameters of piperidine and cyclohexane are found from a high level of ab initio theory including adjustments for basis set dependence and for correlation of the core electrons. Equilibrium rotational constants are obtained from GS rotational constants corrected for vibration-rotation interactions and electronic contributions. Equilibrium structures for piperidine and cyclohexane are fitted by the mixed estimation method. In this method, structural parameters are fitted concurrently to predicate parameters (with appropriate uncertainties) and moments of inertia (with uncertainties). The new structures are regarded as being accurate to 0.001 Å and 0.2°. Comparisons are made between bond parameters in equatorial piperidine and cyclohexane. Another interesting result of this study is that a structure determination is an effective way to check the accuracy of the ground state experimental rotational constants. PMID:25000518

Demaison, Jean; Craig, Norman C; Groner, Peter; Ecija, Patricia; Cocinero, Emilio J; Lesarri, Alberto; Rudolph, Heinz Dieter

2014-07-16

443

Shear viscosity and out of equilibrium dynamics  

E-print Network

Using Grad's method, we calculate the entropy production and derive a formula for the second-order shear viscosity coefficient in a one-dimensionally expanding particle system, which can also be considered out of chemical equilibrium. For a one-dimensional expansion of gluon matter with Bjorken boost invariance, the shear tensor and the shear viscosity to entropy density ratio $\\eta/s$ are numerically calculated by an iterative and self-consistent prescription within the second-order Israel-Stewart hydrodynamics and by a microscopic parton cascade transport theory. Compared with $\\eta/s$ obtained using the Navier-Stokes approximation, the present result is about 20% larger at a QCD coupling $\\alpha_s \\sim 0.3$(with $\\eta/s\\approx 0.18$) and is a factor of 2-3 larger at a small coupling $\\alpha_s \\sim 0.01$. We demonstrate an agreement between the viscous hydrodynamic calculations and the microscopic transport results on $\\eta/s$, except when employing a small $\\alpha_s$. On the other hand, we demonstrate that for such small $\\alpha_s$, the gluon system is far from kinetic and chemical equilibrium, which indicates the break down of second-order hydrodynamics because of the strong noneqilibrium evolution. In addition, for large $\\alpha_s$ ($0.3-0.6$), the Israel-Stewart hydrodynamics formally breaks down at large momentum $p_T\\gtrsim 3$ GeV but is still a reasonably good approximation.

Andrej El; Zhe Xu; Carsten Greiner; Azwinndini Muronga

2009-06-18

444

MHD Turbulent Mixing Layers: Equilibrium Cooling Models  

E-print Network

We present models of turbulent mixing at the boundaries between hot (T~10^{6-7} K) and warm material (T~10^4 K) in the interstellar medium, using a three-dimensional magnetohydrodynamical code, with radiative cooling. The source of turbulence in our simulations is a Kelvin-Helmholtz instability, produced by shear between the two media. We found, that because the growth rate of the large scale modes in the instability is rather slow, it takes a significant amount of time (~1 Myr) for turbulence to produce effective mixing. We find that the total column densities of the highly ionized species (C IV, N V, and O VI) per interface (assuming ionization equilibrium) are similar to previous steady-state non-equilibrium ionization models, but grow slowly from log N ~10^{11} to a few 10^{12} cm^{-2} as the interface evolves. However, the column density ratios can differ significantly from previous estimates, with an order of magnitude variation in N(C IV)/N(O VI) as the mixing develops.

A. Esquivel; R. A. Benjamin; A. Lazarian; J. Cho; S. N. Leitner

2006-05-02

445

Turbulence modeling for non-equilibrium flow  

NASA Technical Reports Server (NTRS)

The work performed during this year has involved further assessment and extension of the k-epsilon-v(exp 2) model, and initiation of work on scalar transport. The latter is introduced by the contribution of Y. Shabany to this volume. Flexible, computationally tractable models are needed for engineering CFD. As computational technology has progressed, the ability and need to use elaborate turbulence closure models has increased. The objective of our work is to explore and develop new analytical frameworks that might extend the applicability of the modeling techniques. In past years the development of a method for near-wall modeling was described. The method has been implemented into a CFD code and its viability has been demonstrated by various test cases. Further tests are reported herein. Non-equilibrium near-wall models are needed for some heat transfer applications. Scalar transport seems generally to be more sensitive to non-equilibrium effects than is momentum transport. For some applications turbulence anisotropy plays a role and an estimate of the full Reynolds stress tensor is needed. We have begun work on scalar transport per se, but in this brief I will only report on an extension of the k-epsilon-v(exp 2) model to predict the Reynolds stress tensor.

Durbin, P. A.

1995-01-01

446

Mechanical equilibrium of a heated anharmonic solid  

NASA Astrophysics Data System (ADS)

A new substantiation has been proposed for for the dependence of the dynamic part of the thermal energy of an anharmonic solid on its strain in terms of the perturbation theory in the anharmonicity constant. The inclusion of this dependence in the internal energy of a solid leads to the fact that the so-called "thermal" pressure force is added to internal elasticity forces. The solution of the equation of the mechanical equilibrium is the equation of state of the solid—the dependence of its macroscopic deformation on temperature and external load. In the absence of external forces, the mechanical equilibrium of the heated solid is reduced to the equilibration of internal forces, which makes it possible to determine the thermal strain of the solid, and the dependence of the strain on the external load also explains the thermoelastic effect—the variation in the solid temperature during its adiabatic mechanical loading. It is shown that the thermal and mechanical strains are summed in the first order of the perturbation theory.

Gorobey, N. N.; Luk'yanenko, A. S.

2015-01-01

447

Reconstructing equilibrium entropy and enthalpy profiles from non-equilibrium pulling  

NASA Astrophysics Data System (ADS)

The Jarzynski identity can be applied to instances when a microscopic system is pulled repeatedly but quickly along some coordinate, allowing the calculation of an equilibrium free energy profile along the pulling coordinate from a set of independent non-equilibrium trajectories. Using the formalism of Wiener stochastic path integrals in which we assign temperature-dependent weights to Langevin trajectories, we derive exact formulae for the temperature derivatives of the free energy profile. This leads naturally to analytical expressions for decomposing a free energy profile into equilibrium entropy and internal energy profiles from non-equilibrium pulling. This decomposition can be done from trajectories evolved at a unique temperature without repeating the measurement as done in finite-difference decompositions. Three distinct analytical expressions for the entropy-energy decomposition are derived: using a time-dependent generalization of the weighted histogram analysis method, a quasi-harmonic spring limit, and a Feynman-Kac formula. The three novel formulae of reconstructing the pair of entropy-energy profiles are exemplified by Langevin simulations of a two-dimensional model system prototypical for force-induced biomolecular conformational changes. Connections to single-molecule experimental means to probe the functionals needed in the decomposition are suggested.

Jeong, Daun; Andricioaei, Ioan

2013-03-01

448

Reconstructing equilibrium entropy and enthalpy profiles from non-equilibrium pulling.  

PubMed

The Jarzynski identity can be applied to instances when a microscopic system is pulled repeatedly but quickly along some coordinate, allowing the calculation of an equilibrium free energy profile along the pulling coordinate from a set of independent non-equilibrium trajectories. Using the formalism of Wiener stochastic path integrals in which we assign temperature-dependent weights to Langevin trajectories, we derive exact formulae for the temperature derivatives of the free energy profile. This leads naturally to analytical expressions for decomposing a free energy profile into equilibrium entropy and internal energy profiles from non-equilibrium pulling. This decomposition can be done from trajectories evolved at a unique temperature without repeating the measurement as done in finite-difference decompositions. Three distinct analytical expressions for the entropy-energy decomposition are derived: using a time-dependent generalization of the weighted histogram analysis method, a quasi-harmonic spring limit, and a Feynman-Kac formula. The three novel formulae of reconstructing the pair of entropy-energy profiles are exemplified by Langevin simulations of a two-dimensional model system prototypical for force-induced biomolecular conformational changes. Connections to single-molecule experimental means to probe the functionals needed in the decomposition are suggested. PMID:23534630

Jeong, Daun; Andricioaei, Ioan

2013-03-21

449

Reconstructing Equilibrium Entropy and Enthalpy Profiles from Non-equilibrium Pulling  

E-print Network

The Jarzynski identity can be applied to instances when a microscopic system is pulled repeatedly but quickly along some coordinate, allowing the calculation of an equilibrium free energy profile along the pulling coordinate from a set of independent non-equilibrium trajectories. Using the formalism of Wiener stochastic path integrals in which we assign temperature-dependent weights to Langevin trajectories, we derive exact formulae for the temperature derivatives of the free energy profile. This leads naturally to analytical expressions for decomposing a free energy profile into equilibrium entropy and internal energy profiles from non-equilibrium pulling. This decomposition can be done from trajectories evolved at a unique temperature without repeating the measurement as done in finite-difference decompositions. Three distinct analytical expressions for the entropy-energy decomposition are derived: using a time-dependent generalization of the weighted histogram analysis method, a quasi harmonic spring limit, and a Feynman-Kac formula. The three novel formulae of reconstructing the pair of entropy-energy profiles are exemplified by Langevin simulations of a two-dimensional model system prototypical for force-induced biomolecular conformational changes. Connections to single-molecule experimental means to probe the functionals needed in the decomposition are suggested.

Daun Jeong; Ioan Andricioaei

2012-10-31

450

Trunk biomechanical models based on equilibrium at a single-level violate equilibrium at other levels  

PubMed Central

Accurate estimation of muscle forces in various occupational tasks is critical for a reliable evaluation of spinal loads and subsequent assessment of risk of injury and management of back disorders. The majority of biomechanical models of multi-segmental spine estimate muscle forces and spinal loads based on the balance of net moments at a single level with no consideration for the equilibrium at remaining levels. This work aimed to quantify the extent of equilibrium violation and alterations in estimations when such models are performed at different levels. Results are compared with those of kinematics-driven model that satisfies equilibrium at all levels and EMG data. Regardless of the method used (optimization or EMG-assisted), single-level free body diagram models yielded estimations that substantially altered depending on the level considered (i.e., level dependency). Equilibrium of net moment was also grossly violated at remaining levels with the error increasing in more demanding tasks. These models may, however, be used to estimate spinal compression forces. PMID:17136359

Arjmand, N.; Parnianpour, M.

2006-01-01

451

Form factors in equilibrium and non-equilibrium mixed states of the Ising model  

NASA Astrophysics Data System (ADS)

Using the ‘Liouville space’ (the space of operators) of the massive Ising model of quantum field theory, there is a natural definition of form factors in any mixed state. These generalize the usual form factors, and are building blocks for mixed-state correlation functions. We study the cases of mixed states that are diagonal in the asymptotic particle basis, and obtain exact expressions for all mixed-state form factors of order and disorder fields. We use novel techniques based on deriving and solving a system of non-linear functional differential equations. We then write down the full form factor expansion for mixed-state correlation functions of these fields. Under weak analytic conditions on the eigenvalues of the density matrix, this is an exact large-distance expansion. The form factors agree with the known finite-temperature form factors when the mixed state is specialized to a thermal Gibbs ensemble. Our results can be used to analyze correlation functions in generalized Gibbs ensembles (which occur after quantum quenches). Applying this to the density matrix for non-equilibrium steady states with energy flows, we observe that non-equilibrium form factors have branch cuts in rapidity space. We verify that this is in agreement with a non-equilibrium generalization of the KMS relations, and we conjecture that the leading large-distance behavior of order and disorder non-equilibrium correlation functions contains oscillations in the log of the distance between the fields.

Chen, Yixiong; Doyon, Benjamin

2014-09-01

452

Renyi statistics in equilibrium statistical mechanics  

E-print Network

The Renyi statistics in the canonical and microcanonical ensembles is examined in the general case and in particular for the ideal gas. In the microcanonical ensemble the Renyi statistics is equivalent with the Boltzmann-Gibbs statistics. By the exact analytical results for the ideal gas, it is shown that in the canonical ensemble in the thermodynamic limit the Renyi statistics is also equivalent with the Boltzmann-Gibbs statistics. Furthermore it satisfies the requirements of the equilibrium thermodynamics, i.e. the thermodynamical potential of the statistical ensemble is a homogeneous function of degree 1 of its extensive variables of state. We conclude that the Renyi statistics duplicates the thermodynamical relations stemming from the Boltzmann-Gibbs statistics in the thermodynamical limit.

A. S. Parvan; T. S. Biro

2009-10-16

453

Dynamic Stability of Equilibrium Capillary Drops  

NASA Astrophysics Data System (ADS)

We investigate a model for contact angle motion of quasi-static capillary drops resting on a horizontal plane. We prove global in time existence and long time behavior (convergence to equilibrium) in a class of star-shaped initial data for which we show that topological changes of drops can be ruled out for all times. Our result applies to any drop which is initially star-shaped with respect to a small ball inside the drop, given that the volume of the drop is sufficiently large. For the analysis, we combine geometric arguments based on the moving-plane type method with energy dissipation methods based on the formal gradient flow structure of the problem.

Feldman, William M.; Kim, Inwon C.

2014-03-01

454

Generation of composite galaxies in dynamic equilibrium  

NASA Astrophysics Data System (ADS)

We present a program to construct disk galaxies in dynamic equilibrium using the moment-based approach. The method is highly modular, allowing components such as bulges, halos, point-particle black holes, and interstellar clouds to be easily added or removed. The gravitational potential and its derivatives for a given galactic configuration are stored on a high-resolution linear/exponential grid in the R-z plane and can be scaled based on component mass. This allows one grid to be used for different sets of initial conditions, drastically reducing computing time. The method is used to initialize and simulate two coaxial, counterrotating disk galaxies undergoing a vertical merger, among other simulations.

Fasano, Robert; Comins, Neil

2015-01-01

455

Stochastic driven systems far from equilibrium  

NASA Astrophysics Data System (ADS)

We study the dynamics and steady states of two systems far from equilibrium: a 1-D driven lattice gas and a driven Brownian particle with inertia. (1) We investigate the dynamical scaling behavior of a 1-D driven lattice gas model with two species of particles hopping in opposite directions. We confirm numerically that the dynamic exponent is equal to z = 1.5. We show analytically that a quasi-particle representation relates all phase points to a special phase line directly related to the single-species asymmetric simple exclusion process. Quasi-particle two-point correlations decay exponentially, and in such a manner that quasi-particles of opposite charge dynamically screen each other with a special balance. The balance encompasses all over the phase space. These results indicate that the model belongs to the Kardar-Parisi-Zhang (KPZ) universality class. (2) We investigate the non-equilibrium thermodynamics of a Brownian particle with inertia under feedback control of its inertia. We find such open systems can act as a molecular refrigerator due to an entropy pumping mechanism. We extend the fluctuation theorems to the refrigerator. The entropy pumping modifies both the Jarzynski equality and the fluctuation theorems. We discover that the entropy pumping has a dual role of work and heat. We also investigate the thermodynamics of the particle under a hydrodynamic interaction described by a Langevin equation with a multiplicative noise. The Stratonovich stochastic integration prescription involved in the definition of heat is shown to be the unique physical choice.

Kim, Kyung Hyuk

456

The Lewis Chemical Equilibrium Program with parametric study capability  

NASA Technical Reports Server (NTRS)

The program was developed to determine chemical equilibrium in complex systems. Using a free energy minimization technique, the program permits calculations such as: chemical equilibrium for assigned thermodynamic states; theoretical rocket performance for both equilibrium and frozen compositions during expansion; incident and reflected shock properties; and Chapman-Jouget detonation properties. It is shown that the same program can handle solid coal in an entrained flow coal gasification problem.

Sevigny, R.

1981-01-01

457

Non-equilibrium fluctuations at the QCD phase transition  

E-print Network

We study the chiral phase transition by the non-equilibrium propagation of the sigma field. A quark fluid acts as a heat bath in local thermal equilibrium and evolves fluid dynamically. We allow for dissipative processes and fluctuations since the sigma field is propagated according to a Langevin-type equation of motion. Non-equilibrium fluctuations at the first order phase transition lead to an increase in the intensity of sigma excitations.

Marlene Nahrgang; Marcus Bleicher

2010-11-24

458

Local temperature of out-of-equilibrium quantum electron systems  

NASA Astrophysics Data System (ADS)

We show how the local temperature of out-of-equilibrium, quantum electron systems can be consistently defined with the help of an external voltage and temperature probe. We determine sufficient conditions under which the temperature measured by the probe (i) is independent of details of the system-probe coupling, (ii) is equal to the temperature obtained from an independent current-noise measurement, (iii) satisfies the transitivity condition expressed by the zeroth law of thermodynamics, and (iv) is consistent with Carnot's theorem. This local temperature therefore characterizes the system in the common sense of equilibrium thermodynamics, but remains well defined even in out-of-equilibrium situations with no local equilibrium.

Meair, J.; Bergfield, J. P.; Stafford, C. A.; Jacquod, Ph.

2014-07-01

459

Implementation of the Non-equilibrium Ionization Code in ISIS  

NASA Astrophysics Data System (ADS)

The non-equilibrium ionization is present in a wide range of astrophysical phenomena such as colliding winds in X-ray binaries, outflows in AGNs, and shock flows in the IGM. Challenges are significant when applying the non-equilibrium ionization code to the Chandra HETG observations. Parallelism has been used to speed up the calculations. Modular software techniques enable us to compute atomic rates directly in ISIS. We present the implementation of our non-equilibrium ionization code in ISIS based on all the available update atomic data. In addition, we demonstrate several applications to the non-equilibrium ionization plasma for the Chandra HETG observations.

Ji, Li; Noble, M.; Houck, J.; Schulz, N. S.; Nowak, M.; Marshall, H. L.

2009-09-01

460

Equilibrium existence and uniqueness in impure public good models  

E-print Network

public goods; Equilibrium existence and uniqueness JEL classification: C72; H41 1. Introduction Models (Sander and Murdoch, 1990), agricultural research (Khanna et al., 1994), household refuse collection

Kotchen, Matthew J.

461

A survey of upwind methods for flows with equilibrium and non-equilibrium chemistry and thermodynamics  

NASA Technical Reports Server (NTRS)

Several versions of flux-vector split and flux-difference split algorithms were compared with regard to general applicability and complexity. Test computations were performed using curve-fit equilibrium air chemistry for an M = 5 high-temperature inviscid flow over a wedge, and an M = 24.5 inviscid flow over a blunt cylinder for test computations; for these cases, little difference in accuracy was found among the versions of the same flux-split algorithm. For flows with nonequilibrium chemistry, the effects of the thermodynamic model on the development of flux-vector split and flux-difference split algorithms were investigated using an equilibrium model, a general nonequilibrium model, and a simplified model based on vibrational relaxation. Several numerical examples are presented, including nonequilibrium air chemistry in a high-temperature shock tube and nonequilibrium hydrogen-air chemistry in a supersonic diffuser.

Grossman, B.; Garrett, J.; Cinnella, P.

1989-01-01

462

Equilibrium econophysics: A unified formalism for neoclassical economics and equilibrium thermodynamics  

NASA Astrophysics Data System (ADS)

We develop a unified conceptual and mathematical structure for equilibrium econophysics, i.e., the use of concepts and tools of equilibrium thermodynamics in neoclassical microeconomics and vice versa. Within this conceptual structure the results obtained in microeconomic theory are: (1) the definition of irreversibility in economic behavior; (2) the clarification that the Engel curve and the offer curve are not descriptions of real processes dictated by the maximization of utility at constant endowment; (3) the derivation of a relation between elasticities proving that economic elasticities are not all independent; (4) the proof that Giffen goods do not exist in a stable equilibrium; (5) the derivation that ‘economic integrability’ is equivalent to the generalized Le Chatelier principle and (6) the definition of a first order phase transition, i.e., a transition between separate points in the utility function. In thermodynamics the results obtained are: (1) a relation between the non-dimensional isothermal and adiabatic compressibilities and the increase or decrease in the thermodynamic potentials; (2) the distinction between mathematical integrability and optimization behavior and (3) the generalization of the Clapeyron equation.

Sousa, Tânia; Domingos, Tiago

2006-11-01

463

Self-assembly and transformation of hybrid nano-objects and nanostructures under equilibrium and non-equilibrium conditions  

Microsoft Academic Search

Understanding how chemically derived processes control the construction and organization of matter across extended and multiple length scales is of growing interest in many areas of materials research. Here we review present equilibrium and non-equilibrium self-assembly approaches to the synthetic construction of discrete hybrid (inorganic-organic) nano-objects and higher-level nanostructured networks. We examine a range of synthetic modalities under equilibrium conditions

Stephen Mann

2009-01-01

464

Clefted Equilibrium Shapes of Superpressure Balloon Structures  

NASA Astrophysics Data System (ADS)

This thesis presents a numerical and analytical study of the clefted equilibrium shape of superpressure balloon structures. Lobed superpressure balloons have shown a tendency to deploy into unexpected asymmetric shapes, hence their design has to strike a balance between the lower stresses achieved by increasing lobing and the risk of incomplete deployment. Extensive clefting is a regular feature of balloons that are incompletely inflated, and is regularly seen during launch and ascent. Our particular interest in the research is in clefts that remain once a balloon has reached its float altitude and is fully pressurized. A simplified simulation technique for orthotropic viscoelastic membranes has been presented in the thesis. Wrinkling is detected by a combined stress-strain criterion and an iterative scheme searches for the wrinkle angle using a pseudo-elastic material stiffness matrix based on a non-linear viscoelastic constitutive model. This simplified model has been implemented in ABAQUS/Explicit and is able to compute the behavior of a membrane structure by superposition of a small number of response increments. The model has been tested against a published solution for a time-independent isotropic membrane under simple shear and also against experimental results on StratoFilm 420 under simple shear. A fully three-dimensional finite element model of balloon structures incorporating wrinkling and frictionless contact, able to simulate the shapes taken up by lobed superpressure balloons during the final stages of their ascent has been established. Two different methods have been considered to predict the clefts: (i) deflation & inflation method and (ii) constraint shift method. In method I, the starting configuration is obtained by deflating an initially symmetric balloon subject to uniform pressure. The deflation simulation is continued until the differential pressure at the bottom of the balloon has become negative, at which point the balloon is extensively clefted. The balloon is then inflated by increasing the bottom pressure while maintaining a uniform vertical pressure gradient, and the evolution of the shape and stress distribution of the balloon is studied. Two different designs of superpressure balloons are investigated: a flat facet balloon and a highly lobed balloon. It is found that the flat facet balloon follows essentially the same path during deflation and inflation, and hence will deploy into a unique, symmetric shape. For the lobed balloon it is found that it follows different paths during deflation and inflation, and deployed into an alternate, clefted equilibrium shape. Compared to method I, method II is a more efficient computational clefting test. The test consists in setting up the balloon in its symmetrically inflated configuration, then breaking the symmetry of this shape by artificially introducing a clefting imperfection, and finally determining the equilibrium shape of the balloon. The clefting imperfection is computed by shifting the constraint at the bottom of the balloon and removing the pressure in the bottom region, below the shifted constraint. The clefting test is applied successfully to three 27˜m diameter superpressure balloons that have been tested indoors by NASA, of which one had remained clefted when it was inflated and the other two had deployed completely. In addition to numerical simulations, formulation of a new cleft ( CF6) factor, employed as an indicator of tendency to S-cleft for superpressure balloons based on constant-stress design has been established through dimensional analysis. The cleft factor, defined as the ratio of clefted volume to cyclically symmetrical volume, is expressed in the form of power law relation of the dimensionless groups. An example illustrates how to calculate the coefficients of the analytical formula and analyze sensitivity of design parameters of clefting.

Deng, Xiaowei

465