Sample records for isobaric vapor-liquid equilibrium

  1. Isobaric vapor–liquid equilibrium for binary mixtures of 2-methylpentane+ethanol and +2-methyl-2-propanol

    Microsoft Academic Search

    Antonio Aucejo; Sonia Loras; Rosa Muñoz; Luis Miguel Ordoñez

    1999-01-01

    Vapor–liquid equilibrium (VLE) data for the binary systems, 2-methylpentane+ethanol and 2-methylpentane+2-methyl-2-propanol (TBA), are reported at 101.3 kPa, including pure component vapor pressures. The systems deviate remarkably from ideal behaviour presenting one positive azeotrope. The activity coefficients and boiling points of the solutions were correlated with its composition by Wilson, UNIQUAC, NRTL, and Wisniak–Tamir equations.

  2. Isobaric vapor–liquid equilibrium for binary and ternary mixtures of ethanol+2-methyl-2-propanol and 2-methylpentane+ethanol+2-methyl-2-propanol

    Microsoft Academic Search

    Antonio Aucejo; Sonia Loras; Rosa Muñoz; Luis Miguel Ordoñez

    1999-01-01

    Consistent vapor–liquid equilibrium data for the binary and ternary systems ethanol+2-methyl-2-propanol (TBA) and 2-methylpentane+ethanol+TBA are reported at 101.3 kPa. In the binary system, the results indicate a negative deviation from ideality and no azeotrope is present. The ternary system shows negative and positive deviations from ideality, does not present azeotrope, and is well predicted from binary data. The activity coefficients

  3. Vapor-liquid equilibrium of amine-water systems 

    E-print Network

    Chun, Kil Whan

    1966-01-01

    VAPOR-LIQUID EQUILIBRIUM OF AMINE-WATER SYSTEMS A Thesis By KIL WHAN CHUN Submitted to the Graduate College of the Texas AS, M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1966 Major... Subject: Chemical Engineering VAPOR-LIQUID EQUILIBRIUM OF AMINE-WATER SYSTEMS A Thesis By KIL WHAN CHUN Approved as to style and content by: C airman of Committee) ead of D partment) (V ember) (Member ) (M ember) January 1966 ACKNOWLEDGMENTS...

  4. Isobaric vapor-liquid equilibria of octane + 1-butanol, + 2-butanol, and + 2-methyl-2-propanol at 101.3 kPa

    Microsoft Academic Search

    Toshihiko Hiaki; Akira Taniguchi; Tomoya Tsuji; Masaru Hongo; Kazuo Kojima

    1996-01-01

    Isobaric vapor-liquid equilibria were measured for three binary systems of 1-butanol + octane, 2-butanol + octane, and 2-methyl-2-propanol + octane at 101.3 kPa. The measurements were made in an equilibrium still with circulation of both the vapor and liquid phases. Both 1-butanol + octane and 2-butanol + octane form a minimum boiling azeotrope. 2-Methyl-2-propanol + octane is a nonazeotrope. The

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

    SciTech Connect

    Susial, P.; Ortega, J. (Univ. de Las Palmas de Gran Canaria, Canary Islands (Spain). Lab. de Termodinamica y Fisicoquimica)

    1993-10-01

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

  6. Analysis of Vapor-Liquid-Liquid Equilibrium in Coal Conversion Processes

    SciTech Connect

    Sampath, V.R.; Leipziger, S.

    1985-04-01

    A new framework for analysis of vapor-liquid-liquid equilibrium has been developed. In this framework, the pure liquid fugacity is defined as the reference fugacity for all solvent species, and Henry's constant is defined as the reference fugacity for all solute species. This applies to vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium as well. A data reduction scheme that generates a consistent set of Henry's constant and activity coefficient parameters from isothermal and nonisothermal binary vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium data has been developed. The results of data reduction for several sets of vapor-liquid, liquid-liquid, and vapor-liquid-liquid equilibrium data are presented.

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

    E-print Network

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

  8. John Arthur McLees, Jr. Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at

    E-print Network

    Rochelle, Gary T.

    Copyright by John Arthur McLees, Jr. 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water in Engineering The University of Texas at Austin May, 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water games, and road trips that I am very excited to be staying here in Austin to watch him progress through

  9. Recommended Vapor-Liquid Equilibrium Data. Part 4. Binary Alkanol-Alkene/Alkyne Systems

    NASA Astrophysics Data System (ADS)

    Góral, Marian; Bok, Andrzej; Kasprzycka-Gutman, Teresa; Oracz, Pawe?

    2006-12-01

    The recommended vapor-liquid equilibrium (VLE) data for binary mixtures of alkanols with alkenes and alkynes have been selected after critical evaluation of all data reported in the open literature up to the end of 2003. 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 Wilson equation as well as with equation of state appended with chemical term (EoSC) proposed by Góral. The recommended data for 18 systems are presented in the form of individual pages containing tables of data, figures, and auxiliary information. Each page corresponds to one system and contains three isotherms (spaced by at least 15K) and one isobar (preferably at 101.32kPa). Experimental gaps were completed with the predicted data.

  10. Recommended Vapor-Liquid Equilibrium Data. Part 3. Binary Alkanol-Aromatic Hydrocarbon Systems

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

    The recommended vapor-liquid equilibrium (VLE) data for mixtures of alkanols with benzene and alkylbenzenes have been selected after critical evaluation of all data 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 for 29 systems are presented in the form of individual pages containing tables of data, figures and auxiliary information. Each page 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.

  11. Recommended Vapor-Liquid Equilibrium Data. Part 1: Binary n-Alkanol-n-Alkane Systems

    NASA Astrophysics Data System (ADS)

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

    2002-09-01

    The recommended vapor-liquid equilibrium (VLE) data for 39 binary n-alcohol-n-alkane systems have been obtained after critical evaluation of all data (490 data sets) reported in the open literature up to the middle of 2001. 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 the local compositions concept as well as with the equation of state appended with a chemical term (EoSC) proposed by Góral. The recommended data are presented in the form of individual pages containing tables of data, figures, and auxiliary information. Each page 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.

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

    NASA Astrophysics Data System (ADS)

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

    2003-12-01

    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.

  13. Vapor-liquid equilibrium thermodynamics of N2 + CH4 - Model and Titan applications

    NASA Technical Reports Server (NTRS)

    Thompson, W. R.; Zollweg, John A.; Gabis, David H.

    1992-01-01

    A thermodynamic model is presented for vapor-liquid equilibrium in the N2 + CH4 system, which is implicated in calculations of the Titan tropospheric clouds' vapor-liquid equilibrium thermodynamics. This model imposes constraints on the consistency of experimental equilibrium data, and embodies temperature effects by encompassing enthalpy data; it readily calculates the saturation criteria, condensate composition, and latent heat for a given pressure-temperature profile of the Titan atmosphere. The N2 content of condensate is about half of that computed from Raoult's law, and about 30 percent greater than that computed from Henry's law.

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

    SciTech Connect

    Susial, P.; Ortega, J. (Catedra de Termodinamica y Fisicoquimica, Escuela Superior de Ingenieros Industriales, Polytechnic University of Canarias, 35017 Las Palmas, Canary Islands (ES)); DeAlfonso, C.; Alonso, C. (Unidad de Tribologia e Ingenieria Quimica, Instituto Rocasolano, CSIC, Madrid (ES))

    1989-04-01

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

  15. Vapor-liquid equilibrium measurements at 101. 32 kPa for binary mixtures of methyl acetate + ethanol or 1-propanol

    SciTech Connect

    Ortega, J.: Susial, P.; de Alfonso, C. (Catedra de Termodinamica y Fisicoquimica, Escuela Superior de Ingeieros Industriales, 35071 Univ. of Las Palmas (ES))

    1990-07-01

    This paper reports on isobaric vapor-liquid equilibrium data at 101.32 {plus minus} 0.02 kPa for methyl acetate (1) + ethane (2) or + 1-propanol (2). The results are compared with those predicted by the UNIFAC and ASOG methods. The methyl acetate (1) + ethanol (2) system forms an azeotrope at 329.8 K and a molar concentration of x{sub 1} = 0.958. Both methods predict the vapor-phase compositions equally well, with overall mean errors of less than 5%.

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

    SciTech Connect

    Jongcheon Lee; Hwayong Kim [Seoul National Univ., Soeul (Korea, Republic of); Jong Sung Lim; Jae-Duck Kim; Youn Yong Lee [CFC Alternatives Technology Center, Seoul (Korea, Republic of)

    1996-12-31

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

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

    NASA Astrophysics Data System (ADS)

    Kiss, Péter T.; Baranyai, András

    2012-11-01

    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.

  18. Vapor-liquid equilibrium calculation of the system water-nitric acid over the entire concentration range

    Microsoft Academic Search

    Stefano Brandani; Vincenzo Brandani

    1996-01-01

    The vapor-liquid equilibrium of the system water-nitric acid has been described. The activity coefficients in the liquid phase are evaluated according to a new model. This model combines the effect of the long range forces expressed by a Debye-Hückel contribution on a mole fraction basis, with the effect of short range forces expressed by a virial expansion of the NRTL

  19. Vapor-Liquid Equilibrium in the Mixture Dimethyl sulfoxide C2H6OS + C8H10 Ethylbenzene (EVLM1211, LB5640_E)

    NASA Astrophysics Data System (ADS)

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

    This document is part of Subvolume B 'Binary Liquid Systems of Nonelectrolytes II' 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 + C8H10 Ethylbenzene (EVLM1211, LB5640_E)' providing data from direct measurement of temperature at variable mole fraction in liquid phase and constant pressure.

  20. Lattice Boltzmann Simulation of Vapor-Liquid Equilibrium on 3d Finite Lattice

    Microsoft Academic Search

    Gusztáv Mayer; Gábor Házi; Attila R. Imre; Thomas Kraska; Leonid V. Yelash

    2004-01-01

    Numerical calculations for three-dimensional vapor-liquid equilibria have been accomplished by lattice Boltzmann simulations. The aim of this investigation is to test the capability of the lattice Boltzmann method in comparison with solutions obtained by the underlying equation of state. As a result we have found a finite-size effect (just like the ones obtained in one and two dimensions) at small

  1. Effect of ionic liquids on (vapor + liquid) equilibrium behavior of (water + 2-methyl-2-propanol)

    Microsoft Academic Search

    Lianzhong Zhang; Bingbang Qiao; Yun Ge; Dongshun Deng; Jianbing Ji

    2009-01-01

    Isobaric T, x, y data were reported for ternary systems of {water+2-methyl-2-propanol (tert-butyl alcohol, TBA)+ionic liquid (IL)} at p=100kPa. When the mole fraction of TBA on IL-free basis was fixed at 0.95, measurements were performed at IL mass fractions from 0.6 down to 0.05, in a way of repeated synthesis. The vapor-phase compositions were obtained by analytical methods and the

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    PubMed

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

    2015-06-14

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

  7. Isothermal vapor–liquid equilibrium data for the carbon dioxide (R744) + decafluorobutane (R610) system at temperatures from 263 to 353 K

    Microsoft Academic Search

    Alain Valtz; Xavier Courtial; Erik Johansson; Christophe Coquelet; Deresh Ramjugernath

    2011-01-01

    Isothermal vapor–liquid equilibrium data are presented for the carbon dioxide (CO2)+decafluorobutane (C4F10) system. Measurements were performed for seven isotherms (three isotherms below and four above the critical temperature of CO2) ranging from 263.15 to 352.98K, with pressure ranging from 0.0727 to 6.8628MPa. The measurements were undertaken using a “static-analytic” type apparatus, with sampling of the equilibrium phases via pneumatic capillary

  8. Vapor-liquid equilibrium data of ethanethiol and tetrahydrothiopene in propane

    Microsoft Academic Search

    John W. Goetzinger; Dennis W. Brinkman; Bruce E. Poling; Marvin L. Whisman

    1977-01-01

    Equilibrium K values for the odorants ethanethiol, tetrahydrothiophene, and a mixture of the two in propane were determined at -23, 0, and 35°C. A technique was used in which samples from both the vapor and liquid phases were analyzed by gas chromatography, which gave K values to +-5%.

  9. The calculation of ternary vapor-liquid system equilibrium by using PR equation of state

    Microsoft Academic Search

    Yi Liu; Jianzhong Yin; Runjie Liu; Wenhua Shi; Wei Wei

    By using P-R equation of state (EOS), the phase equilibrium characteristics was simulated for a system consisted of hydrogen-hexane-dicyclopentadiene (DPD). In order to improve the accuracy of the simulation, different ?functions and mixing rules were respectively used to modify the P-R EOS. The molar concentrations in vapor and liquid phase calculated was contrasted with that of the experimental data cited

  10. (Vapor + liquid) equilibrium data for (carbon dioxide + 1,1-difluoroethane) system at temperatures from (258 to 343) K and pressures up to about 8 MPa

    Microsoft Academic Search

    Hakim Madani; Alain Valtz; Christophe Coquelet; Abdeslam Hassen Meniai; Dominique Richon

    2008-01-01

    Accurate thermo-physical data are of utmost interest for the development of new efficient refrigeration systems. Carbon dioxide (R744) and 1,1-difluoroethane (R152a) are addressed here. Isothermal (vapor+liquid) equilibrium data are reported herein for (R744+R152a) binary system in the (258–343) K temperature range and in the (0.14 to 7.65) MPa pressure range. A reliable “static-analytic” method taking advantage of two online ROLSI™

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

    E-print Network

    Mills, Anna Lisa

    1988-01-01

    from 0. 5 to 5. 0 kg/ms/s at a constant gas flow rate. Schwartz et al. (1976) compared the apparent equilibrium constant of a linearly adsorbing tracer determined from a trickle-bed reactor to that obtained from totally wetted pellets. The internal... kg/ms/s, and independent of the gas flow rates of lx10 to 2x10 kg/mz/s. The tracer methods of Schwartz and Colombo were applied to cyclo- hexene and n-pentane tracers on activated alumina particles by Mills and Dudukovic (1981). As in the case...

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

    SciTech Connect

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

    1993-10-01

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

  13. Vapor-liquid equilibrium correlations for systems containing amines using a lattice fluid equation of state with hydrogen bonding

    Microsoft Academic Search

    Alexander Breitholz; Ki-Pung Yoo; Jong Sung Lim; Chul Soo Lee; Jeong Won Kang

    2008-01-01

    The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of vapor-liquid\\u000a equilibria (VLE) for binary amine and hydrocarbon mixture at various temperatures. For these mixtures, the consideration of\\u000a hydrogen bondings in the lattice equation of state clearly improves the prediction for VLE. The amines were divided into four\\u000a groups due to the different

  14. Vapor-Liquid Equilibrium in the Mixture Pentafluoroethane C2HF5 + C2H2F4 1,1,1,2-Tetrafluoroethane (EVLM1311, LB5632_E)

    NASA Astrophysics Data System (ADS)

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

    This document is part of Subvolume A 'Binary Liquid Systems of Nonelectrolytes I' 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 Pentafluoroethane C2HF5 + C2H2F4 1,1,1,2-Tetrafluoroethane (EVLM1311, LB5632_E)' providing data from direct measurement of pressure at variable temperature and constant mole fraction in liquid phase.

  15. Vapor-Liquid Equilibrium in the Mixture 1,1,1,2-Tetrafluoroethane C2H2F4 + C4H10O2 2,5-Dioxahexane (EVLM1111, LB5748_E)

    NASA Astrophysics Data System (ADS)

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

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'vapor-Liquid Equilibrium in the Mixture 1,1,1,2-Tetrafluoroethane C2H2F4 + C4H10O2 2,5-Dioxahexane (EVLM1111, LB5748_E)' providing data from direct measurement of pressure at variable mole fraction in liquid phase and constant temperature.

  16. Vacuum freezing type ice slurry production using ethanol solution 1st report: Measurement of vapor–liquid equilibrium data of ethanol solution at 20 °C and at the freezing temperature

    Microsoft Academic Search

    Tatsunori Asaoka; Akio Saito; Seiji Okawa; Tetsuya Ito; Naoki Izumi

    2009-01-01

    In this study, an original method for the production of ice slurry from ethanol solution without using a refrigerator is proposed. This system has advantages compared with similar existing systems using materials other than ethanol solution. In this paper, the vapor–liquid equilibrium data of ethanol solution at 20°C and at the freezing temperature are measured, which is necessary to calculate

  17. Applications of the Simple Multi-Fluid Model to Correlations of the Vapor-Liquid Equilibrium of Refrigerant Mixtures Containing Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Akasaka, Ryo

    This study presents a simple multi-fluid model for Helmholtz energy equations of state. The model contains only three parameters, whereas rigorous multi-fluid models developed for several industrially important mixtures usually have more than 10 parameters and coefficients. Therefore, the model can be applied to mixtures where experimental data is limited. Vapor-liquid equilibrium (VLE) of the following seven mixtures have been successfully correlated with the model: CO2 + difluoromethane (R-32), CO2 + trifluoromethane (R-23), CO2 + fluoromethane (R-41), CO2 + 1,1,1,2- tetrafluoroethane (R-134a), CO2 + pentafluoroethane (R-125), CO2 + 1,1-difluoroethane (R-152a), and CO2 + dimethyl ether (DME). The best currently available equations of state for the pure refrigerants were used for the correlations. For all mixtures, average deviations in calculated bubble-point pressures from experimental values are within 2%. The simple multi-fluid model will be helpful for design and simulations of heat pumps and refrigeration systems using the mixtures as working fluid.

  18. Vapor-liquid equilibria for 1,1,1-trifluoro-2-(2,2,2-trifluoroethoxy)ethane +2-methyl-2-propanol and pentane+1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane system

    Microsoft Academic Search

    Toshihiko Hiaki; Shingo Fujita; Tomoya Tsuji; Shingo Urata; Junji Mizukado

    2003-01-01

    Isobaric vapor-liquid equilibrium (VLE) for two binary systems of 1,1,1-Trifluoro-2-(2,2,2-trifluoroethoxy) ethane+2-methyl-2-propanol\\u000a and pentane+1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane system have been measured at 101.3 kPa. The measurements were\\u000a made in an equilibrium still, developed in a previous study, with circulation of both the vapor and liquid phases. The binary\\u000a isobaric systems exhibit minimum boiling azeotropes. The thermodynamic consistencies of the experimental data were good by

  19. Densities and vapor-liquid equilibria in binary mixtures formed by propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol at 160.0 kPa

    SciTech Connect

    Falcon, J.; Ortega, J.; Gonzalez, E. [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica] [Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Laboratorio de Termodinamica y Fisicoquimica

    1996-07-01

    Densities and excess volumes were determined at 298.15 K for propyl methanoate + ethanol, + propan-1-ol, and + butan-1-ol. The results of those quantities were then correlated to get the concentrations of vapor-liquid equilibrium obtained isobarically at 160 kPa for the same mixtures. Two mixtures show azeotropes: for propyl methanoate (1) + ethanol (2), x{sub 1} = 0.443 at T = 358.7 K; and for propyl methanoate (1) + propan-1-ol (2), x{sub 1} = 0.762 at T = 368.2 K. The mixtures are thermodynamically consistent, and the predictions made using several group-contribution models are satisfactory.

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

    E-print Network

    Zhang, Luzheng

    equilibrium constants, Henry's constant, experimental data, and data regression on the representation of the VLE of the system was discussed in detail. The equilibrium constant of the carbamate reversion degradation. (d) It has a relatively low solubility for hydrocarbon which reduces the hydrocarbon loss when

  1. A study of new mixture combining rules for prediction of vapor-liquid equilibria 

    E-print Network

    Shyu, Guor-Shiarn

    1993-01-01

    Wong and Sandler published two important articles in 1992 that established new mixture combining rules (MCR) for use with cubic equations of state (EOS) in the prediction and correlation of vapor-liquid equilibrium (VLE) ...

  2. Vapor–liquid equilibria for binary and ternary systems composed of 2-methoxy-2-methyl propane, 2-methyl-2-propanol, and octane at 101.3 kPa

    Microsoft Academic Search

    Toshihiko Hiaki; Kazuteru Tatsuhana; Tomoya Tsuji; Masaru Hongo

    1999-01-01

    Isobaric vapor–liquid equilibria for 2-methoxy-2-methyl propane (MTBE)+2-methyl-2-propanol+octane and the constituent binary system MTBE+2-methyl-2-propanol have been measured at 101.3 kPa. The measurements were made in an equilibrium still with circulation of both the vapor and liquid phases. The ternary system of MTBE+2-methyl-2-propanol+octane and the binary system of MTBE+2-methyl-2-propanol are both non-azeotropic. The constituent binary systems of 2-methyl-2-propanol+octane and MTBE+octane, which were

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

    ERIC Educational Resources Information Center

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

    2010-01-01

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

  4. (Vapour + liquid) equilibrium of binary mixtures (1,3-dioxolane or 1,4-dioxane + 2-methyl-1-propanol or 2-methyl-2-propanol) at isobaric conditions

    Microsoft Academic Search

    Antonio Reyes; Carlos Lafuente; José Miñones; Udo Kragl; Félix M Royo

    2004-01-01

    Isobaric (vapour+liquid) equilibrium of (1,3-dioxolane or 1,4-dioxane+2-methyl-1-propanol or 2-methyl-2-propanol) at 40.0 kPa and 101.3 kPa has been studied with a dynamic recirculating still. The experimental VLE data are thermodynamically consistent. From these data, activity coefficients were calculated and correlated with the Margules, van Laar, Wilson, NRTL and UNIQUAC equations. The VLE results have been compared with the predictions by the

  5. Vapor-liquid phase separator permeability results

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    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.

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

    SciTech Connect

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

    1993-04-01

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

  8. Isothermal vapor–liquid equilibria for mixtures of 4-methoxyphenol, catechol, and p-cresol

    Microsoft Academic Search

    Shou-Ming Hwang; Ming-Jer Lee; Ho-mu Lin

    2000-01-01

    Isothermal vapor–liquid equilibrium data are measured with a static apparatus for the binary and ternary mixtures composed of 4-methoxyphenol, catechol (1,2-dihydroxybenzene ), and p-cresol (4-methylphenol) at temperatures ranging from 423.15 to 453.15K. While minimum pressure azeotropes are exhibited in 4-methoxyphenol+catechol, no azeotropes are found in the rest of the systems. The new binary data are correlated with the Wilson, the

  9. Vapor-liquid coexistence of the Stockmayer fluid in nonuniform external fields

    E-print Network

    Sela Samin; Yoav Tsori; Christian Holm

    2013-03-10

    We investigate the structure and phase behavior of the Stockmayer fluid in the presence of nonuniform electric fields using molecular simulation. We find that an initially homogeneous vapor phase undergoes a local phase separation in a nonuniform field due to the combined effect of the field gradient and the fluid vapor--liquid equilibrium. This results in a high density fluid condensing in the strong field region. The system polarization exhibits a strong field dependence due to the fluid condensation.

  10. Vapor-Liquid Equilibria for Some Concentrated Aqueous PolymerSolutions

    SciTech Connect

    Striolo, Alberto; Prausnitz, John M.

    1999-07-01

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

  11. Vapor-liquid-solid growth of germanium nanostructures on silicon

    NASA Astrophysics Data System (ADS)

    Dailey, J. W.; Taraci, J.; Clement, T.; Smith, David J.; Drucker, Jeff; Picraux, S. T.

    2004-12-01

    The pressure and temperature dependencies for vapor-liquid-solid (VLS) growth of Ge nanostructures on Si using chemical vapor deposition are reported. Gold nanodots self-assembled by evaporation on clean hydrogen-terminated and heated Si substrates are used to seed the liquid eutectic VLS growth. Digermane pressures are varied from 4×10-5 to 1×10-2Torr and substrate temperatures from 400 to 600°C for heteroepitaxial growth on Si(111). Two types of nanostructures are identified, nanowires and nanopillars, with a transition from nanopillar growth to nanowire growth occurring with increasing pressure. Nanowires are characterized by rapid vertical growth, long-aspect-ratio structures, and linear dependence of the growth rate on pressure. At lower pressures a transition to nanopillars is observed; these exhibit both vertical and lateral growth with typical aspect ratios of 1:2. For Si(111) substrates nanowires grow epitaxially with their growth axis along the ?111? direction. High-resolution transmission electron microscopy shows that the Ge nanowires are relaxed to their equilibrium lattice spacings a short distance from the Si substrate interface.

  12. Vapor-liquid equilibrium of amine-water systems

    E-print Network

    Chun, Kil Whan

    1966-01-01

    methods of this type for predicting deviations from ideality is that of Hildebrand (43), which employs solubility parameters calculated from molar volumes and heats of vaporization. A similar approach has been developed by Gilmont, Zudkevitch...

  13. Binary vapor-liquid equilibrium data without measurement of composition 

    E-print Network

    Nehzat, Mohammad Sadegh

    1975-01-01

    Saturated liquid 2 Saturated vapor 65 APPENDIX D Isochores for Peed Composition of 33. 335 mold n-Butane Zsochore Number 1 Density= 0. 74129 lb mol/ft 3 lemperature (oP) Pressure (psia) 1 Sat. Liq. 2 Sat. Yap. Densit lb mol ft 460. 0 400. 0 340... magnetic densimeter. In this work, Hall and Eubank's method is applied to a carbon dioxide-normal butane mixture, studied by Olds, et al (15). Since the apparatus used by these investigators was not a Burnett-Isochoric apparatus, a simulation program...

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

    E-print Network

    Sciortino, Francesco

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

  15. Isobaric vapour–liquid equilibrium for the binary mixtures of 2-methyl-2-propanol with some halohydrocarbons at 40.0 and 101.3 kPa

    Microsoft Academic Search

    H Artigas; C Lafuente; S Mart??n; J Miñones; F. M Royo

    2001-01-01

    Vapour–liquid equilibria of the binary systems 2-methyl-2-propanol+chlorocyclohexane, chlorobenzene, bromocyclohexane or bromobenzene have been determined at two constant pressures, 40.0 and 101.3kPa. The equipment used was a dynamic recirculating still. The isobaric VLE data have been found to be thermodynamically consistent according to the point-to-point test of Van Ness. The activity coefficients have been correlated with the mole fraction through Margules,

  16. Vapor-liquid-solid growth of germanium nanostructures on silicon

    Microsoft Academic Search

    J. W. Dailey; J. Taraci; T. Clement; David J. Smith; Jeff Drucker; S. T. Picraux

    2004-01-01

    The pressure and temperature dependencies for vapor-liquid-solid (VLS) growth of Ge nanostructures on Si using chemical vapor deposition are reported. Gold nanodots self-assembled by evaporation on clean hydrogen-terminated and heated Si substrates are used to seed the liquid eutectic VLS growth. Digermane pressures are varied from 4×10-5 to 1×10-2 Torr and substrate temperatures from 400 to 600°C for heteroepitaxial growth

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

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

    SciTech Connect

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

    2011-10-13

    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.

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

    Microsoft Academic Search

    Ismail Kul; Darryl D DesMarteau; Adolph L Beyerlein

    2000-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  1. Size-Dependent Phase Diagram of Nanoscale Alloy Drops Used in Vapor-Liquid-Solid Growth of Semiconductor Nanowires

    SciTech Connect

    Sutter, E.; Sutter, P.

    2010-07-19

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

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

    PubMed

    Sutter, Eli A; Sutter, Peter W

    2010-08-24

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

  3. Isothermal vapor–liquid equilibria of octane with 1-butanol, 2-butanol, or 2-methyl-2-propanol

    Microsoft Academic Search

    Toshihiko Hiaki; Akira Taniguchi; Tomoya Tsuji; Masaru Hongo

    1998-01-01

    Isothermal vapor–liquid equilibria were measured for three binary systems of 1-butanol+octane at 373.15 K, 2-butanol+octane at 358.15 K, and 2-methyl-2-propanol+octane at 343.15 K. The measurements were made in a Rogalski–Malanowski type equilibrium still with circulation of both the vapor and liquid phases. Three binary isothermal systems form a maximum pressure azeotrope. The azeotropic data are x1(AZ)=0.519 mole fraction and P(AZ)=75.71

  4. 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

  5. Measurement and model prediction of vapor-liquid equilibria of mixtures of rapeseed oil and supercritical carbon dioxide

    SciTech Connect

    Klein, T.; Schulz, S. (Lehrstuhl fur Thermodynamik, Abteilung Chemietechnik, Universitat Dortmund, D-4600 Dortmund 50 (DE))

    1989-07-01

    Isothermal-vapor-liquid equilibrium data of the rapeseed oil-carbon dioxide system were measured with a vapor-recirculation apparatus at 313.15, 333.15, 353.15, and 373.15 K at pressures between 10 and 85 MPa. The solubilities of rapeseed oil in carbon dioxide were compared with solubility data of other vegetable oils from the literature. A lattice model equation of state (EOS) is used to describe the rapeseed oil-carbon dioxide system. The lattice EOS was improved by introducing a more accurate EOS for carbon dioxide (Bender EOS) into the model. With the Kumar-Bender model and a tree-binary-parameter, composition- and density-dependent combining rule proposed by Wilczek-Vera and Vera, a quantitative description of phase equilibrium is obtained. The temperature dependence of the binary parameters has been evaluated for interpolation or extrapolation purposes.

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

    PubMed

    Rajesh, John Anthuvan; Pandurangan, Arumugam

    2014-04-01

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

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

    USGS Publications Warehouse

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

    1978-01-01

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

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

    E-print Network

    Boles, Steven Tyler

    2010-01-01

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

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

    SciTech Connect

    Mun, S.Y.; Lee, H.

    1999-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  11. Magnetotail dynamics under isobaric constraints

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  12. Design, fabrication and performance evaluation of a vaporizing liquid microthruster

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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.

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

    PubMed

    Lu, Haiming; Meng, Xiangkang

    2015-01-01

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

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

    PubMed Central

    Lu, Haiming; Meng, Xiangkang

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

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

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

    PubMed

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

    2012-08-28

    Grand-canonical transition-matrix Monte Carlo and histogram reweighting techniques are used herein to study the vapor-liquid coexistence properties of two-dimensional (2D) flexible oligomers with varying chain lengths (m = 1-8). The phase diagrams of the various 2D oligomers follow the correspondence state (CS) principle, akin to the behavior observed for bulk oligomers. The 2D critical density is not influenced by the oligomer chain length, which contrasts with the observation for the bulk oligomers. Line tension, calculated using Binder's formalism, in the reduced plot is found to be independent of chain length in contrast to the 3D behavior. The dynamical properties of 2D fluids are evaluated using molecular dynamics simulations, and the velocity and pressure autocorrelation functions are investigated using Green-Kubo (GK) relations to yield the diffusion and viscosity. The viscosity determined from 2D non-equilibrium molecular dynamics simulation is compared with the viscosity estimated from the GK relations. The GK relations prove to be reliable and efficient for the calculation of 2D transport properties. Normal diffusive regions are identified in dense oligomeric fluid systems. The influence of molecular size on the diffusivity and viscosity is found to be diminished at specific CS points for the 2D oligomers considered herein. In contrast, the viscosity and diffusion of the 3D bulk fluid, at a reduced temperature and density, are strongly dependent on the molecular size at the same CS points. Furthermore, the viscosity increases and the diffusion decreases multifold in the 2D system relative to those in the 3D system, at the CS points. PMID:22938253

  17. Molecular Simulation of Henry's Constant at Vapor-Liquid and Liquid-Liquid Phase Richard J. Sadus

    E-print Network

    Molecular Simulation of Henry's Constant at Vapor-Liquid and Liquid-Liquid Phase Boundaries Richard to determine Henry's constant from the residual chemical potential at infinite dilution at the vapor-liquid coexistence. 1. Introduction Henry's constant is a well-known measure of a solute's solubility in a particular

  18. Efficiency of a gas-vapor-liquid thermal curtain behind a tangential slot

    NASA Astrophysics Data System (ADS)

    Vasil'Ev, A. A.

    The efficiency of the thermal protection of an adiabatic wall involving the injection of a gas-vapor-liquid mixture is calculated on the basis of the asymptotic theory of a turbulent boundary layer. Experimental values of the efficiency of an air-steam-water thermal curtain behind a tangential slot are obtained, and a comparison is made between the calculated and experimental values.

  19. Virial coefficients and vapor-liquid equilibria of the EXP6 and 2-Yukawa fluids

    E-print Network

    J. Krejcí; I. Nezbeda; R. Melnyk; A. Trokhymchuk

    2011-07-20

    Virial coefficients $B_2$ through $B_4$ and the vapor-liquid equilibria for the EXP6 and 2-Yukawa (2Y) fluids have been determined using numerical integrations and Gibbs ensemble simulations, respectively. The chosen 2Y models have been recently determined as an appropriate reference fluid for the considered EXP6 models.

  20. Status report on the measurement of vapor--liquid equilibria

    Microsoft Academic Search

    Kobayashi

    1976-01-01

    Hydrogen-rich binary and multicomponent systems are being studied by two different approaches: (1) A perturbation chromatographic approach developed at Rice University over the years, and; (2) An equilibrium cell which can be operated in either the flow or batch mode. Apparatus components for (1) are being purchased, designed-constructed at Rice, and moved from other parts of the Rice University Thermodynamic--Transport

  1. Vapor–liquid equilibria of ammonia + ionic liquid mixtures

    Microsoft Academic Search

    A. Yokozeki; Mark B. Shiflett

    2007-01-01

    Solubilities of ammonia in room-temperature ionic liquids, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium ethylsulfate, and N,N-dimethylethanolammonium acetate have been measured for the first time. Static phase equilibrium cells used in our previous work have been slightly modified for the present solubility measurements. Six mixture compositions of each binary system were prepared for the present experiments from about 30 to 85mol% of

  2. Geometry of the Vapor Liquid Coexistence in the Gibbs Space

    E-print Network

    Eduardo Piña

    2011-11-12

    The phase coexistence is illuminated with geometric views of the thermodynamic variables, according to Gibbs' choices. Quantities and relations between them are obtained. The existence of the edge of regression with tangents coincident with the straight lines connecting the coexistence points of phase equilibrium is stressed. A geometric approach to the critical point leads to estimation of the values of the critical exponents for the angles formed by the coexistence curve and the straight lines with the principal direction along the minimal curvature.

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

    E-print Network

    Mills, Anna Lisa

    1988-01-01

    coefficients; (8) pressure drop does not influence the conversion; (9) plug flow of the liquid phase. Bondi (1971) developed an empirical relationship between the ob- served reaction rate constant, k , in a trickle-bed to the intrinsic 0 rate constant, k...

  4. Modeling vapor–liquid equilibrium of various binary mixtures with a statistically based equation of state

    Microsoft Academic Search

    Mohammad Mehdi Papari; Jalil Moghadasi; Fatemeh Fadaei; Antonio Campo

    The present study is a continuation of previous work (F. Yousefi, J. Moghadasi, M. M. Papari, A. Campo, Ind. Eng. Chem. Res. 48 (2009) 5079–5084) related to the assessment of the ability of the Tao-Mason (TM) equation of state (EOS) in predicting thermodynamic properties of fluid mixtures. In our previous study, we extended the TM EOS to predict pressure–volume–temperature–composition of

  5. Vapor-liquid phase equilibrium in systems with multiple chemical reactions

    Microsoft Academic Search

    Sophie Ung; Michael F. Doherty

    1995-01-01

    We introduce a new set of composition variables for treating phase equilibria in multicomponent, multi-reaction systems with or without inert components present. These variables provide a way of reducing the dimensionality of the problem and simplifying the analysis. We find that reactive azeotropes occur at points of equal transformed composition in each phase, but not equal mole fraction. Therefore, phase

  6. Isobaric groundwater well

    DOEpatents

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

    1999-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  9. Growth of Narrow and Straight Germanium Nanowires by Vapor--Liquid--Solid Chemical Vapor Deposition

    Microsoft Academic Search

    Marolop Simanullang; Koichi Usami; Tetsuo Kodera; Ken Uchida; Shunri Oda

    2011-01-01

    This paper describes the growth of germanium nanowires (Ge NWs) via vapor--liquid--solid (VLS) mechanism by the low-pressure chemical vapor deposition (CVD) technique. A systematic study of the growth conditions of the Ge NWs has been conducted by varying the size of the Au nanoparticles and the substrate temperature. The tapering of the nanowires has been minimised when the growth temperature

  10. The experimental application of X-ray tomography to a vapor–liquid contactor

    Microsoft Academic Search

    Carolyn E. Schmit; Dwight B. Cartmel; R. Bruce Eldridge

    2001-01-01

    Initial results obtained from the application of X-ray tomography to an operating vapor–liquid contactor indicate that the technology has the potential to provide insight into the underlying hydraulic behavior of a packed column. Experiments were performed with counter-current air–water flows in a 6-in-diameter contactor packed with random packing. Liquid and gas velocities typical of a commercial column were tested. Liquid

  11. Growth of epitaxial silicon and germanium nanowires using the gold catalyzed vapor-liquid-solid mechanism

    Microsoft Academic Search

    Eric J. Dailey

    2010-01-01

    The growth of silicon and germanium nanowires and their nanowire heterostructures has been investigated using the gold catalyzed vapor-liquid-solid (VLS) mechanism. The Au catalyst particles were deposited under ultra high vacuum (UHV) conditions onto vicinal Si(111) surfaces using physical vapor deposition. Nanowires were grown in a home built UHV-chemical vapor deposition (CVD) chamber using silane, disilane, germane, and digermane as

  12. Heterogeneously Integrated Vapor–Liquid–Solid Grown Silicon Probes\\/(111) and Silicon MOSFETs\\/(100)

    Microsoft Academic Search

    Akihiro Okugawa; Kotaro Mayumi; Akihito Ikedo; Makoto Ishida; Takeshi Kawano

    2011-01-01

    In this letter, we report the heterogeneous integra- tion of vertically aligned silicon (Si) microprobe arrays\\/(111) with MOSFET circuits\\/(100) by IC processes and subsequent selective vapor-liquid-solid (VLS) growth of Si. A hybrid Si-on-insulator (SOI) substrate with different species of Si lay- ers, e.g., a (100)-top-Si\\/buried oxide\\/(111)-handle-Si system, was utilized for the heterogeneous integration technique. MOSFETs were fabricated on (100) top

  13. Composition and growth direction control of epitaxial vapor-liquid-solid-grown SiGe nanowires

    NASA Astrophysics Data System (ADS)

    Dailey, Eric; Madras, Prashanth; Drucker, Jeff

    2010-10-01

    The composition and growth direction of epitaxial SiGe alloy nanowires (NWs) grown via the Au-catalyzed vapor-liquid-solid technique can be controlled by varying growth conditions. These alloy NWs can adopt either Si-like or Ge-like characteristics. Si-like growth is characterized by Au-coated ?111?-oriented NWs for low pressure growth and Au-free ?112?-oriented NWs for higher pressure growth. Ge-like NWs always follow ?111? and grow with Au-free sidewalls.

  14. The influence of the liquid slab thickness on the planar vapor-liquid interfacial tension

    E-print Network

    Werth, Stephan; Horsch, Martin; Hasse, Hans

    2013-01-01

    One of the long standing challenges in molecular simulation is the description of interfaces. On the molecular length scale, finite size effects significantly influence the properties of the interface such as its interfacial tension, which can be reliably investigated by molecular dynamics simulation of planar vapor-liquid interfaces. For the Lennard-Jones fluid, finite size effects are examined here by varying the thickness of the liquid slab. It is found that the surface tension and density in the center of the liquid region decreases significantly for thin slabs. The influence of the slab thickness on both the liquid density and the surface tension is found to scale with 1/S^3 in terms of the slab thickness S, and a linear correlation between both effects is obtained. The results corroborate the analysis of Malijevsk\\'y and Jackson, J. Phys.: Cond. Mat. 24: 464121 (2012), who recently detected an analogous effect for the surface tension of liquid nanodroplets.

  15. The influence of the liquid slab thickness on the planar vapor-liquid interfacial tension

    E-print Network

    Stephan Werth; Sergey Lishchuk; Martin Horsch; Hans Hasse

    2013-01-11

    One of the long standing challenges in molecular simulation is the description of interfaces. On the molecular length scale, finite size effects significantly influence the properties of the interface such as its interfacial tension, which can be reliably investigated by molecular dynamics simulation of planar vapor-liquid interfaces. For the Lennard-Jones fluid, finite size effects are examined here by varying the thickness of the liquid slab. It is found that the surface tension and density in the center of the liquid region decreases significantly for thin slabs. The influence of the slab thickness on both the liquid density and the surface tension is found to scale with 1/S^3 in terms of the slab thickness S, and a linear correlation between both effects is obtained. The results corroborate the analysis of Malijevsk\\'y and Jackson, J. Phys.: Cond. Mat. 24: 464121 (2012), who recently detected an analogous effect for the surface tension of liquid nanodroplets.

  16. Growth of Narrow and Straight Germanium Nanowires by Vapor-Liquid-Solid Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Simanullang, Marolop; Usami, Koichi; Kodera, Tetsuo; Uchida, Ken; Oda, Shunri

    2011-10-01

    This paper describes the growth of germanium nanowires (Ge NWs) via vapor-liquid-solid (VLS) mechanism by the low-pressure chemical vapor deposition (CVD) technique. A systematic study of the growth conditions of the Ge NWs has been conducted by varying the size of the Au nanoparticles and the substrate temperature. The tapering of the nanowires has been minimised when the growth temperature is lowered from 300 to 280 °C which also contributes to the decrease in the diameter of the Ge NWs. The growth temperature of 280 °C yields Ge NWs with diameters of less than 5 nm, offering an opportunity for the fabrication of high-performance germanium nanowire field-effect transistors.

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

    SciTech Connect

    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

    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.

  18. Analysis of vapor-liquid-solid mechanism in Au-assisted GaAs nanowire growth

    NASA Astrophysics Data System (ADS)

    Harmand, J. C.; Patriarche, G.; Péré-Laperne, N.; Mérat-Combes, M.-N.; Travers, L.; Glas, F.

    2005-11-01

    GaAs nanowires were grown by molecular-beam epitaxy on (111)B oriented surfaces, after the deposition of Au nanoparticles. Different growth durations and different growth terminations were tested. After the growth of the nanowires, the structure and the composition of the metallic particles were analyzed by transmission electron microscopy and energy dispersive x-ray spectroscopy. We identified three different metallic compounds: the hexagonal ?'Au7Ga2 structure, the orthorhombic AuGa structure, and an almost pure Au face centered cubic structure. We explain how these different solid phases are related to the growth history of the samples. It is concluded that during the wire growth, the metallic particles are liquid, in agreement with the generally accepted vapor-liquid-solid mechanism. In addition, the analysis of the wire morphology indicates that Ga adatoms migrate along the wire sidewalls with a mean length of about 3?m.

  19. Vapor-liquid interfacial properties of rigid-linear Lennard-Jones chains

    NASA Astrophysics Data System (ADS)

    Blas, F. J.; Ignacio Moreno-Ventas Bravo, A.; Míguez, J. M.; Piñeiro, M. M.; MacDowell, L. G.

    2012-08-01

    We have obtained the interfacial properties of short rigid-linear chains formed from tangentially bonded Lennard-Jones monomeric units from direct simulation of the vapour-liquid interface. The full long-range tails of the potential are accounted for by means of an improved version of the inhomogeneous long-range corrections of Jane?ek [J. Phys. Chem. B 110, 6264-6269 (2006)], 10.1021/jp056344z proposed recently by MacDowell and Blas [J. Chem. Phys. 131, 074705 (2009)], 10.1063/1.3197009 valid for spherical as well as for rigid and flexible molecular systems. Three different model systems comprising of 3, 4, and 5 monomers per molecule are considered. The simulations are performed in the canonical ensemble, and the vapor-liquid interfacial tension is evaluated using the test-area method. In addition to the surface tension, we also obtain density profiles, coexistence densities, critical temperature and density, and interfacial thickness as functions of temperature, paying particular attention to the effect of the chain length and rigidity on these properties. According to our results, the main effect of increasing the chain length (at fixed temperature) is to sharpen the vapor-liquid interface and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness decreases and the surface tension increases as the molecular chains get longer. The surface tension has been scaled by critical properties and represented as a function of the difference between coexistence densities relative to the critical density.

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

    E-print Network

    Straub, John E.

    Order parameter free enhanced sampling of the vapor-liquid transition using the generalized replica://jcp.aip.org/authors #12;THE JOURNAL OF CHEMICAL PHYSICS 138, 104119 (2013) Order parameter free enhanced sampling-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling

  1. Temporal and spatial relationships between topography, atmospheric water vapor, liquid water and vegetation endmember fractions determined using AVIRIS

    Microsoft Academic Search

    D. A. Roberts; R. O. Green; J. B. Adams; J. S. Cothern; D. E. Sabol; M. O. Smith

    1994-01-01

    Temporal and spatial changes in water vapor, liquid water and endmember fractions were investigated using AVIRIS data collected in the vicinity of Jasper Ridge, CA, on three dates in 1992. Water vapor and liquid water were mapped using a Modtran-II based atmospheric model that accounts for spatially varying atmospheric properties. Spectral mixture analysis (SMA) was used to model vegetation as

  2. Measurements of the Vapor-Liquid Coexistence Curves and the Critical Parameters of HCFC123 and HFC134a

    NASA Astrophysics Data System (ADS)

    Fukushima, Masato; Watanabe, Naohiro; Kamimura, Toru

    The critical parameters and vapor-liquid coexistence curves in the critical region of two environmentally acceptable hydrogen-containing halocarbons (HCFC123 and HFC134a) were determined experimentally. The measurements of vapor-liquid coexistence curves were made through visual observation of the disappearance of meniscus at the vapor-liquid interface within the optical cell. Thirty eight saturated densities in the range of 209 to 1176 kg/m3 were obtained between the temperature of 392 K and the critical temperature for HCFC123. And seventeen saturated densities in the range of 322 to 746 kg/m3 were obtained between the temperature of 370 K and the critical temperature for HFC134a. On the basis of these results, the critical temperature and critical density of HCFC123 were determined to be 456.94 K and 553 kg/m3, respectively. And these parameters of HFC134a were determined to be 374.18 K and 507 kg/m3. In addition, the critical exponents were determined and the correlation of vapor-liquid coexistence curves were developed.

  3. Coulomb Energies In Isobaric Multiplets

    SciTech Connect

    Bentley, M.A. [School of Chemistry and Physics, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)

    2005-04-05

    Examination of fundamental symmetries is one of the key aspirations in physics research. In nuclear physics, the most fundamental of these is the exchange symmetry between neutrons and protons. The approximate charge symmetry and charge independence of the nuclear force results in striking symmetries in nuclear behavior between isobaric analogue states (IAS) - states of the same isospin quantum number in a set of nuclei of the same total number of nucleons (an isobaric multiplet). The Coulomb force breaks this symmetry and is the dominating factor in producing the large shifts in absolute binding energy between IAS. Until recently, progress in understanding these energy shifts in detail was broadly restricted to the lowest energy states for a given isospin (e.g. the difference in ground state masses of a pair of mirror nuclei). However, the recent advances in spectroscopic techniques - especially the development of large gamma-ray spectrometers - has resulted in a wealth of information on IAS at high excitation energy and high angular momentum. The very small differences in excitation energy between the IAS can be interpreted, principally, in terms of Coulomb effects. The analysis of these Coulomb differences has been shown to be a remarkably sensitive probe of nuclear structure effects as well as providing stringent tests of state-of-the-art shell-model calculations. In this review, some of the latest results and their interpretation are presented.

  4. Prediction of the vapor-liquid distribution constants for volatile nonelectrolytes in water up to its critical temperature

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.; Shock, Everett L.

    2003-12-01

    The distribution of solutes between coexisting liquid and vapor phases of water can be expressed by the distribution constant, K D, defined as K D= limitlim x?0y/x, where y and x stand for the mole fraction concentrations of a solute in vapor and liquid phases, respectively. Research reported here is concerned with the prediction of this property, K D, for volatile nonelectrolytes, over the whole temperature range of existence of the vapor-liquid equilibrium for water, i.e. from 273 K to the critical temperature at 647.1 K. A simple empirical method is proposed to extrapolate the values of K D from 298 K to 500-550 K. Calculations at higher temperatures are based on the theoretical relation that establishes the proportionality between RTlnK D and the Krichevskii parameter, A Kr, which is the single most important property of a solute at near-critical conditions, and can be evaluated using the method proposed here. The comparison of predicted and experimental values of K D and A Kr for a few well-studied solutes reveals the satisfactory performance of the proposed method. It appears that the accuracy of predictions in the framework of this method is limited mainly by the accuracy of the values of the thermodynamic functions of hydration of solutes at 298 K, and that the best way to improve the quality of predictions of K D and A Kr is to increase the inventory of accurate calorimetric enthalpy and heat capacity data for aqueous solutes at 298 K. We stress that the values of the Krichevskii parameter, such as those generated in this study, are of crucial importance for reliable predictions of the chemical potential and its derivatives (V 2o, Cp 2o) for aqueous solutes at near-critical and supercritical conditions. Values of K D and A Kr are predicted for many inorganic volatile nonelectrolytes and some halogenated derivatives of methane and ethene. We show that both ln K D and A Kr for aqueous organic solutes follow group additivity systematics, and we derive a set of corresponding group contribution values for several functional groups (material point, CH 3, CH 2, CH, C, C = C, HC = CH, C?C, HC ar, C ar, C fus, OH, O, S, SH, CO, COO, COH, COOH, CN, F, Cl, Br, NH 2, NH, N, etc.).

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

    NASA Astrophysics Data System (ADS)

    How Cheah, Kean; Low, Kay-Soon

    2015-01-01

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

  6. Energy-conversion properties of vapor-liquid-solid-grown silicon wire-array photocathodes.

    PubMed

    Boettcher, Shannon W; Spurgeon, Joshua M; Putnam, Morgan C; Warren, Emily L; Turner-Evans, Daniel B; Kelzenberg, Michael D; Maiolo, James R; Atwater, Harry A; Lewis, Nathan S

    2010-01-01

    Silicon wire arrays, though attractive materials for use in photovoltaics and as photocathodes for hydrogen generation, have to date exhibited poor performance. Using a copper-catalyzed, vapor-liquid-solid-growth process, SiCl4 and BCl3 were used to grow ordered arrays of crystalline p-type silicon (p-Si) microwires on p+-Si(111) substrates. When these wire arrays were used as photocathodes in contact with an aqueous methyl viologen(2+/+) electrolyte, energy-conversion efficiencies of up to 3% were observed for monochromatic 808-nanometer light at fluxes comparable to solar illumination, despite an external quantum yield at short circuit of only 0.2. Internal quantum yields were at least 0.7, demonstrating that the measured photocurrents were limited by light absorption in the wire arrays, which filled only 4% of the incident optical plane in our test devices. The inherent performance of these wires thus conceptually allows the development of efficient photovoltaic and photoelectrochemical energy-conversion devices based on a radial junction platform. PMID:20056886

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

    PubMed Central

    2011-01-01

    In this letter, n-type doping of GaAs nanowires grown by metal–organic vapor phase epitaxy in the vapor–liquid–solid growth mode on (111)B GaAs substrates is reported. A low growth temperature of 400°C is adjusted in order to exclude shell growth. The impact of doping precursors on the morphology of GaAs nanowires was investigated. Tetraethyl tin as doping precursor enables heavily n-type doped GaAs nanowires in a relatively small process window while no doping effect could be found for ditertiarybutylsilane. Electrical measurements carried out on single nanowires reveal an axially non-uniform doping profile. Within a number of wires from the same run, the donor concentrations ND 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.

  8. Vapor–liquid equilibria of ternary systems with 1-ethyl-3-methylimidazolium ethyl sulfate using headspace gas chromatography

    Microsoft Academic Search

    Hiroyuki Matsuda; Katsumi Tochigi; Vincent Liebert; Jürgen Gmehling

    2011-01-01

    Vapor–liquid equilibria (VLE) for two binary systems 1-propanol+water and methyl acetate+methanol, and the ternary mixtures with the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM]+[EtSO4]? as entrainer were measured by headspace gas chromatography. From the experimental VLE data, the influence of the ionic liquid on the separation factors was investigated. The experimental results for the ternary systems show that [EMIM]+[EtSO4]? has a

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

    SciTech Connect

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

    1987-01-01

    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.

  10. Vertically Aligned Various Lengths Doped-Silicon Microwire Arrays by Repeated Selective Vapor-Liquid-Solid Growth

    Microsoft Academic Search

    T. Kawano; A. Ikedo; T. Kawashima; K. Sawada; M. Ishida

    2009-01-01

    We have proposed a growth technique of various lengths, 2-4 mum diameter, conductive-silicon micowire arrays, by repeated vapor-liquid-solid (VLS) growth of n-type silicon, using Au as the growth catalyst and a mixture gas of 1% PH3 with 100% Si2H6 as the silicon gas source. We obtained a longer 100 mum-length silicon wire by both the first growth of 50 mum-length

  11. Air stripping of volatile organic compounds from groundwater: An evaluation of a centrifugal vapor-liquid contractor

    SciTech Connect

    Singh, S.P.

    1989-01-01

    The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2,000 m{sup 2}/m{sup 3}) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function of the specific surface area of the packing and to a lesser extent a function of rotor speed and liquid flow rate. A correlation based on the specific surface area of the packing is proposed for predicting the ATU. A simple empirical model is also proposed for determining the power consumed in turning the packing torus at various operating conditions. Previous claims in the literature that centrifugal vapor-liquid contactor is resistant to fouling because of high shear force were found not to be valid for groundwater with high iron content.

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

    SciTech Connect

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

    1995-03-01

    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.

  13. Phase equilibrium modeling in ethanol + congener mixtures using an artificial neural network

    Microsoft Academic Search

    Claudio A. Faúndez; Felipe A. Quiero; José O. Valderrama

    2010-01-01

    Artificial neural networks have been applied for the correlation and prediction of vapor–liquid equilibrium in binary ethanol mixtures found in alcoholic beverage production. The main interest of the study is the acceptable modeling of the bubble pressure and concentration of congeners (substances different from ethanol) in the vapor phase, considered to be an important enological parameter in the alcoholic industry.

  14. Growth of epitaxial silicon and germanium nanowires using the gold catalyzed vapor-liquid-solid mechanism

    NASA Astrophysics Data System (ADS)

    Dailey, Eric J.

    The growth of silicon and germanium nanowires and their nanowire heterostructures has been investigated using the gold catalyzed vapor-liquid-solid (VLS) mechanism. The Au catalyst particles were deposited under ultra high vacuum (UHV) conditions onto vicinal Si(111) surfaces using physical vapor deposition. Nanowires were grown in a home built UHV-chemical vapor deposition (CVD) chamber using silane, disilane, germane, and digermane as gas precursors. Silicon nanowire morphology was determined to be dependent on the stability of the gold catalyst particle at the tip of the nanowire. Specifically, silicon nanowires grow along <111> orientations when gold wets the nanowire sidewalls and along <112> orientations when gold does not wet the nanowire sidewalls except under a very narrow pressure range. The dependence of gold coverage on CVD parameters on the sidewalls of <111> and <112> silicon nanowires was also determined revealing a liquid metal wetting of cylinders phenomenon. A new "seedless" VLS mechanism for nanowire growth was also determined in which the Stranski-Krastanov planar gold layer on Si(111) dewets under certain CVD conditions resulting in 15 nm diameter gold seeds that then form nanowires via the VLS mechanism. Both core/shell and axial nanowire heterostructures were also investigated with a focus on the effect of nanowire orientation on heterostructure formation. For core/shell heterostructures, only the <110> germanium core/silicon shell heterostructures were determined to form with smooth shell deposition while all other orientations underwent shell roughening. Various germanium core diameters and silicon shell thicknesses for <110> germanium core/silicon shell heterostructures were analyzed to determine the effect of nanowire diameter on shell coherency limits and to determine the strain within the nanowire heterostructures. Lastly, axial nanowire heterostructures were investigated to determine the ability to form axial heterostructures using various nanowire orientations. Only the <110> silicon/germanium axial heterostructure yielded a high proportion of unkinked axial heterostructures while all other orientations yielded 5% or less unkinked axial heterostructures. The interface abruptness was also investigated for various silicon/germanium axial heterostructures with the germanium segment grown above and below the gold/silicon eutectic temperature. The most abrupt heterointerfaces were obtained for the samples grown beneath the eutectic temperature.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  16. Vertically Aligned InP Nanowires Grown via the Self-Assisted Vapor-Liquid-Solid Mode

    NASA Astrophysics Data System (ADS)

    Zhang, Guoqiang; Tateno, Kouta; Gotoh, Hideki; Sogawa, Tetsuomi

    2012-05-01

    We have demonstrated the growth of vertical InP nanowires via the self-assisted vapor-liquid-solid mode on an InP(111) substrate. Single nanowires exhibit a highly uniform diameter along the axial direction despite their 15 µm length. We show direct evidence of the self-assisted growth mode by performing a compositional analysis of the NW tip. We demonstrated that the In particle at the NW tip could be removed by modifying the V/III source material ratio during growth. Single InP nanowires exhibit a distinct TO phonon peak and show the luminescence of the excitonic emission at 4 K.

  17. Isobaric Melt Productivity of Peridotite: Constraints from Simple and Complex Systems

    Microsoft Academic Search

    A. Matzen; M. Baker; E. Stolper

    2006-01-01

    Isobaric melt productivity, (dF\\/dT)P, is an important term in the expression for isentropic melt productivity, (dF\\/dP)S. Theoretical analysis [1] suggests that (dF\\/dT)P is low near the fertile peridotite solidus and increases with increasing melt fraction, F, but experimental studies on natural peridotite bulk compositions yield conflicting results; this ambiguity may reflect difficulty in achieving equilibrium, analyzing low-degree melts, and\\/or calculating

  18. Prediction of heptanes-plus equilibrium ratios from empirical correlations

    E-print Network

    McKenna, Martin James

    1988-01-01

    fluids. Figures 6 and 7 show the distribution of heptanes-plus molecular weight and specific gravity values found in the 385 volatile oil and retrograde gas systems studied. The distribution of heptanes-plus mole fraction in the petroleum fluids... of Advisory Committee: Dr . J . M . Jennings Calculating the phase behavior of hydrocarbon mixtures in vapor-liquid equilibrium is necessary for simulating reservoir fluid performance as well as designing surface equipment for processing petroleum...

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

    EPA Science Inventory

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

  20. 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.

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

    E-print Network

    Yu, Dong

    these materials can be the basis of data storage media such as CD/DVD3 and phase- change random access memoryVapor­Liquid­Solid and Vapor­Solid Growth of Phase-Change Sb2Te3 Nanowires and Sb2Te3/GeTe Nanowire-switching behavior. Introduction Chalcogenides exhibit a reversible crystalline-amorphous phase change induced

  2. An improved method of determining vapor-liquid equilibria for dilute organics in aqueous solution.

    PubMed

    Kieckbusch, T G; King, C J

    1979-05-01

    Chromatographic quantitative analyses of aqueous samples containing dilute concentrations of organic solutes are frequently confounded by sorption phenomena, particularly for vapor samples and aged syringes. A novel apparatus was developed for overcoming this problem; it utilizes continual circulation of gas through a thermostated syringe for sampling, followed by a needleless injection into the chromatograph. Precision and reproducibility well under 0.5% can be obtained in this way. This method was applied to a determination of the solubility of isopentyl acetate in water (2600 ppm) by following the equilibrium vapor response for increasing liquid concentrations. It was also used to determine equilibrium partition coefficients for C1-C5 n-acetates between air and water, over a range of temperatures from 25 to 40 degrees C. PMID:19847988

  3. Gamma-ray Spectroscopy of Isobaric Multiplets

    SciTech Connect

    Bentley, M. A. [Department of Physics, University of York, Heslington, York, YO10 5DD (United Kingdom)

    2006-04-26

    The approximate charge symmetry and charge independence of the nuclear force results in striking symmetries in nuclear behavior between isobaric analogue states (IAS) -- states of the same isospin quantum number in a set of nuclei of the same total number of nucleons (an isobaric multiplet). The Coulomb force breaks this symmetry and is the dominating factor in producing the large shifts in absolute binding energy between IAS. The recent development of large gamma-ray spectrometers has resulted in a wealth of information on IAS at high excitation energy and high angular momentum. The very small differences in excitation energy between the IAS can be interpreted, principally, in terms of Coulomb effects. The analysis of these Coulomb differences has been shown to be a remarkably sensitive probe of nuclear structure effects as well as providing stringent tests of state-of-the-art shell-model calculations. Some specific structural phenomena examined through the study of such energy differences are presented in this review, and include the evolution of nuclear radius/deformation as a function of spin and the electromagnetic spin-orbit effect.

  4. Polarization characteristics of the {triangle} isobar produced in a nucleus

    SciTech Connect

    Balashov, V.V.; Bibikov, A.V.; Vostroknutova, O.N. [Moscow State Univ. (Russian Federation)

    1995-07-01

    The properties of the spin density matrix of the {triangle}isobar produced in a nucleus by pions and photons are studied from the viewpoint of prospects for exclusive (coincidence) experiments on the excitation and decay of the {triangle}isobar in nuclear reactions.

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

    SciTech Connect

    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

    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.

  6. Grand canonical Monte Carlo simulations of vapor-liquid equilibria using a bias potential from an analytic equation of state.

    PubMed

    Castillo Sanchez, Juan Manuel; Danner, Timo; Gross, Joachim

    2013-06-21

    This article introduces an efficient technique for the calculation of vapor-liquid equilibria of fluids. Umbrella Sampling Monte Carlo simulations in the grand canonical ensemble were conducted for various types of molecules. In Umbrella Sampling, a weight function is used for allowing the simulation to reach unlikely states in the phase space. In the present case this weight function, that allows the system to overcome the energetic barrier between a vapor and liquid phase, was determined by a trivialized Density Functional Theory (DFT) using the PC-SAFT equation of state. The implementation presented here makes use of a multicanonical ensemble approach to divide the space of fluctuating particle number N into various subsystems. The a priori estimate of the weight function from the analytic DFT allows the parallelization of the calculation, which significantly reduces the computation time. In addition, it is shown that the analytic equation of state can be used to substitute sampling the dense liquid phase, where the sampling of insertion and deletion moves become demanding. PMID:23802950

  7. Grand canonical Monte Carlo simulations of vapor-liquid equilibria using a bias potential from an analytic equation of state

    NASA Astrophysics Data System (ADS)

    Sanchez, Juan Manuel Castillo; Danner, Timo; Gross, Joachim

    2013-06-01

    This article introduces an efficient technique for the calculation of vapor-liquid equilibria of fluids. Umbrella Sampling Monte Carlo simulations in the grand canonical ensemble were conducted for various types of molecules. In Umbrella Sampling, a weight function is used for allowing the simulation to reach unlikely states in the phase space. In the present case this weight function, that allows the system to overcome the energetic barrier between a vapor and liquid phase, was determined by a trivialized Density Functional Theory (DFT) using the PC-SAFT equation of state. The implementation presented here makes use of a multicanonical ensemble approach to divide the space of fluctuating particle number N into various subsystems. The a priori estimate of the weight function from the analytic DFT allows the parallelization of the calculation, which significantly reduces the computation time. In addition, it is shown that the analytic equation of state can be used to substitute sampling the dense liquid phase, where the sampling of insertion and deletion moves become demanding.

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

    NASA Astrophysics Data System (ADS)

    Pai, Sung Jin; Bae, Young Chan

    2014-08-01

    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.

  9. Neural recording chip with penetrating Si microprobe electrode array by selective vapor-liquid-solid growth method.

    PubMed

    Kawano, Takeshi; Takao, Hidekuni; Sawada, Kazuaki; Ishida, Makoto

    2004-01-01

    This paper reports on the development of neural recording chip device with penetrating Si microprobe electrode array using IC-process. The Si microprobe electrode array each with a few microns in diameter was grown at predetermined positions with interconnection-wirings. Controlling the diameter and the length of Si probes can be realized by a selective vapor-liquid-solid (VLS) growth. In this work, Si probes with 2 mum in diameter and 60 microm in length were fabricated, which were conductive-Si probes and they were encapsulated with SiO2 layers. To reduce the impedance of Si probes, the tips of Si probes were coated with a metal Au layer. As a result, penetrating Si microprobes measured in saline solution, showed impedance of the order of 300 k to 500 komega at 1 kHz. Packaging techniques for the probe chip were performed with a fluid-tight chamber and a flexible-printed-circuit of polyimide for neural recording experiments. PMID:17272127

  10. Vertically aligned silicon microwire arrays of various lengths by repeated selective vapor-liquid-solid growth of n-type silicon\\/n-type silicon

    Microsoft Academic Search

    Akihito Ikedo; Takahiro Kawashima; Takeshi Kawano; Makoto Ishida

    2009-01-01

    Repeated vapor-liquid-solid (VLS) growth with Au and PH3-Si2H6 mixture gas as the growth catalyst and silicon source, respectively, was used to construct n-type silicon\\/n-type silicon wire arrays of various lengths. Silicon wires of various lengths within an array could be grown by employing second growth over the first VLS grown wire. Additionally, the junction at the interface between the first

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

    NASA Astrophysics Data System (ADS)

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

    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.

  12. Isobaric (vapour + liquid) equilibria for sulfolane with toluene, ethylbenzene, and isopropylbenzene at 101.33 kPa

    Microsoft Academic Search

    Zhengrong Wang; Lei Huang; Shuqian Xia; Peisheng Ma

    2011-01-01

    Isobaric (vapour+liquid) equilibrium data have been measured for the (toluene+sulfolane), (ethylbenzene+sulfolane), and (isopropylbenzene+sulfolane) binary systems with a modified Rose-Williams still at 101.33kPa. The experimental data of binary systems were well correlated by the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phase. All the experimental results passed the thermodynamic consistency test by the Herington method.

  13. Shell effects in hot isobaric nuclei

    SciTech Connect

    Rajasekaran, M.; Arunachalam, N.; Rajasekaran, T.R.; Devanathan, V.

    1988-10-01

    Level densities for hot isobaric nuclei are investigated by incorporating the isospin fluctuations in the statistical theory of nuclei. The single-particle level density parameter a is extracted as a function of temperature for various isospins of the system. At large temperatures, the empirical value of aapprox. =A/8 is reproduced. A new method of extracting the neutron-proton asymmetry parameter is proposed. The neutron-proton asymmetry parameter is found to depend very strongly on deformation and isospin at low temperatures. The effect of the shell structure on the asymmetry energy is predominant for certain isospins corresponding to stable neutron-proton combinations. Results are presented for A = 42, 44, 46, and 208. The excitation energy versus isospin plot for constant entropy of the system exhibits pockets similar to yrast traps in high-spin states of highly excited nuclei.

  14. Liquid–liquid equilibrium correlations using lattice fluid equation of state with hydrogen bonding

    Microsoft Academic Search

    Alexander Breitholz; Ki-Pung Yoo; Jong Sung Lim; Chul Soo Lee; Jeong Won Kang

    2008-01-01

    The nonrandom lattice equation of state with hydrogen bonding (NLF-HB EOS) was examined for the correlation of liquid–liquid equilibria (LLE) for binary alcohol and hydrocarbon mixture in a wide pressure range. For hydrocarbon+alcohol mixtures the consideration of a hydrogen-bonding term in the lattice equation of state clearly improves the prediction for vapor–liquid equilibrium (VLE) as shown in previous works, but

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

    SciTech Connect

    Ghobadi, Ahmadreza F.; Elliott, J. Richard, E-mail: elliot1@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325 (United States)

    2014-07-14

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

  16. Vapor–liquid equilibria and critical points for the carbon dioxide +1-pentanol and carbon dioxide +2-pentanol systems at temperatures from 332 to 432 K

    Microsoft Academic Search

    G Silva-Oliver; Luis A Galicia-Luna; S. I Sandler

    2002-01-01

    Vapor–liquid equilibria and critical points of the systems: carbon dioxide+1-pentanol at (333.08, 343.69, 374.93, 414.23 and 426.86K) up to 18.6MPa and carbon dioxide+2-pentanol at (332.10, 343.61, 374.15, 397.56, 422.28 and 431.78K) up to 15.7MPa are reported at compositions near the critical point. An apparatus capable of measurement up to 60MPa and 523K based on the static-analytic method has been used

  17. 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

    Microsoft Academic Search

    1993-01-01

    A program is currently in progress at Argonne National Laboratory to evaluate and develop evaporator technology for concentrating radioactive waste streams. By concentrating radioactive waste streams, disposal costs can be significantly reduced. To effectively reduce the volume of waste, the evaporator must achieve high decontamination factors so that the distillate is sufficiently free of radioactive material. One technology that shows

  18. Clinical Characteristics of Spinal Levobupivacaine: Hyperbaric Compared with Isobaric Solution

    PubMed Central

    Sanansilp, Vimolluck; Trivate, Travuth; Chompubai, Phakaporn; Visalyaputra, Shusee; Suksopee, Pattipa; Permpolprasert, Ladda; von Bormann, Benno

    2012-01-01

    We performed a prospective, double-blinded study in 20 patients undergoing gynecologic surgery with lower abdominal incision, to investigate characteristics of intrathecal hyperbaric levobupivacaine compared with isobaric levobupivacaine. We randomly assigned them to receive 3?mL of either isobaric or hyperbaric 0.42% levobupivacaine intrathecally. We found that hyperbaric levobupivacaine, compared with isobaric levobupivacaine, spread faster to T10 level (2.8 ± 1.1 versus 6.6 ± 4.7 minutes, P = 0.039), reached higher sensory block levels at 5 and 15 minutes after injection (T8 versus L1, P = 0.011, and T4 versus T7, P = 0.027, resp.), and had a higher peak level (T4 versus T8, P = 0.040). Isobaric levobupivacaine caused a wider range of peak levels (L1 to C8) compared with hyperbaric form (T7 to T2). The level of T4 or higher reached 90% in the hyperbaric group compared with 20% in the isobaric group (P = 0.005). Our results suggest that hyperbaric levobupivacaine was more predictable for sensory block level and more effective for surgical procedures with lower abdominal approach. Hyperbaric levobupivacaine seems to be suitable, but the optimal dosage needs further investigation. PMID:22619612

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

    USGS Publications Warehouse

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

    1990-01-01

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

  20. Phase equilibrium measurements on twelve binary mixtures

    SciTech Connect

    Giles, N.F. [Wiltec Research Co., Inc., Provo, UT (United States)] [Wiltec Research Co., Inc., Provo, UT (United States); Wilson, H.L.; Wilding, W.V. [Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.] [Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.

    1996-11-01

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

  1. Double isobaric analog of 11Li in 11B

    NASA Astrophysics Data System (ADS)

    Charity, R. J.; Sobotka, L. G.; Hagino, K.; Bazin, D.; Famiano, M. A.; Gade, A.; Hudan, S.; Komarov, S. A.; Lee, Jenny; Lobastov, S. P.; Lukyanov, S. M.; Lynch, W. G.; Metelko, C.; Mocko, M.; Rogers, A. M.; Sagawa, H.; Sanetullaev, A.; Tsang, M. B.; Wallace, M. S.; van Goethem, M. J.; Wuosmaa, A. H.

    2012-10-01

    The ground state of 11Li is the preeminent example of a two-neutron-halo nucleus and is part of an isobaric sextet. Another member of this sextet, the double isobaric analog of 11Lig.s. in 11B, has been identified in the 12Be(p,2n)11B reaction. The state was discovered through its two-proton decay branch. From detected 2p+9Li events, its excitation energy was determined to be 33.57(8) MeV using the invariant mass method. With the known masses of 11Li and its isobaric analog state in 11Be, three members of the same sextet have measured masses for the first time, permitting the masses of the remaining members to be extrapolated using the isobaric multiplet mass equation. All members of this multiplet are expected to have a two-nucleon halo structure and this was found consistent with the evolution of the mass across the sextet. The momentum correlations of the detected protons were found to have both “diproton” and “cigar” components.

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

    SciTech Connect

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

    1988-02-01

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

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

    Microsoft Academic Search

    Robert W. Shaw; J. P. Young; D. H. Smith

    1988-01-01

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

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

    SciTech Connect

    Chialvo, Ariel A [ORNL; Moucka, Filip [Jan Evangelista Purkyn? University in Ústí nad Labem, Czech Republic; Vlcek, Lukas [ORNL; Nezbeda, Ivo [Jan Evangelista Purkyn? University in Ústí nad Labem, Czech Republic

    2015-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Robertson, F. R.

    1985-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

    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.

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

    PubMed

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

    2010-12-16

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

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

    SciTech Connect

    Maimoni, A.

    1980-01-01

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

  10. Axial pn-junctions formed by MOVPE using DEZn and TESn in vapor-liquid-solid grown GaAs nanowires

    NASA Astrophysics Data System (ADS)

    Regolin, I.; Gutsche, C.; Lysov, A.; Blekker, K.; Li, Zi-An; Spasova, M.; Prost, W.; Tegude, F.-J.

    2011-01-01

    We report on axial pn-junctions in GaAs nanowires. The nanowires were grown by MOVPE on (1 1 1)B GaAs substrates using the vapor-liquid-solid mechanism in combination with Au seed particles. At the low growth temperature of 400 °C any additional growth on the nanowire sidewalls can be excluded such that a pure axial pn-junction is realized. p-Type doping was provided by diethyl zinc, while tetraethyl tin was introduced for n-type doping. The impact of dopant supply was investigated both on structural properties and on carrier density. The carrier type was independently verified by processed nanowire metal-insulator FETs. The lengths of the whole pn-GaAs nanowires reach up to 20 ?m while their diameters are up to a few 100 nm, as defined by the Au seed particles used. The pn-GaAs nanowire device exhibits diode-like I- V characteristics and strong electroluminescence. While the reverse current is in the low pA-regime, the forward current reaches a few ?A, limited by the n-doped side. A diffusion voltage VD=1.4 V is determined, which corresponds to the GaAs band gap energy. To our knowledge this is the first axial GaAs pn-diode realized in a single GaAs nanowire.

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

    PubMed

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

    2010-04-23

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-04-01

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

  13. All-atom force field for the prediction of vapor-liquid equilibria and interfacial properties of HFA134a.

    PubMed

    Peguin, Robson P S; Kamath, Ganesh; Potoff, Jeffrey J; da Rocha, Sandro R P

    2009-01-01

    A new all-atom force field capable of accurately predicting the bulk and interfacial properties of 1,1,1,2-tetrafluoroethane (HFA134a) is reported. Parameterization of several force fields with different initial charge configurations from ab initio calculations was performed using the histogram reweighting method and Monte Carlo simulations in the grand canonical ensemble. The 12-6 Lennard-Jones well depth and diameter for the different HFA134a models were determined by fitting the simulation results to pure-component vapor-equilibrium data. Initial screening of the force fields was achieved by comparing the calculated and experimental bulk properties. The surface tension of pure HFA134a served as an additional screening property to help discriminate an optimum model. The proposed model reproduces the experimental saturated liquid and vapor densities, and the vapor pressure for HFA134a within average errors of 0.7%, 4.4%, and 3.1%, respectively. Critical density, temperature, vapor pressure, normal boiling point, and heat of vaporization at 298 K are also in good agreement with experimental data with errors of 0.2%, 0.1%, 6.2%, 0%, 2.2%, respectively. The calculated surface tension is found to be within the experimental range of 7.7-8.1 mN.m(-1). The dipole moment of the different models was found to significantly affect the prediction of the vapor pressure and surface tension. The ability of the HFA134a models in predicting the interfacial tension against water is also discussed. The results presented here are relevant in the development of technologies where the more environmentally friendly HFA134a is utilized as a substitute to the ozone depleting chlorofluorocarbon propellants. PMID:19086791

  14. Improvement of non-isobaric model for shock ignition

    NASA Astrophysics Data System (ADS)

    Farahbod, Amir Hossein; Abolfazl Ghasemi, Seyed; Jafar Jafari, Mohammad; Rezaei, Somayeh; Sobhanian, Samad

    2014-10-01

    In this paper, improved relations of total fuel energy, fuel gain, hot-spot radius and total areal density in a non-isobaric model of fuel assembly have been derived and compared with the numerical results of [J. Schmitt, J.W. Bates, S.P. Obenschain, S.T. Zalesak, D.E. Fyfe, Phys. Plasmas 17, 042701 (2010); S. Atzeni, A. Marocchino, A. Schiavi, G. Schurtz, New J. Phys. 15, 045004 (2013)] and several simulations performed by MULTI-1D radiation hydrodynamic code for shock ignition scenario. Our calculations indicate that the approximations made by [M.D. Rosen, J.D. Lindl, A.R. Thiessen, LLNL Laser Program Annual Report, UCRL-50021-83, pp. 3-5 (1983); J. Schmitt, J.W. Bates, S.P. Obenschain, S.T. Zalesak, D.E. Fyfe, Phys. Plasmas 17, 042701 (2010)] for the calculation of burn-up fraction are not accurate enough to give results consistent with simulations. Therefore, we have introduced more appropriate approximations for the burn-up fraction and total areal density of the fuel that are in more agreement with simulation results of shock ignition. Meanwhile, it is shown that the related formulas of the non-isobaric model for total fuel energy, fuel gain and also hot-spot radius cannot determine the model parameters independently, but improved model choose a better selection and less restrictions on determination of the parameters for the non-isobaric model. Such derivations can be used in theoretical studies of the ignition conditions and burn-up fraction of the fuel in shock ignition scenario.

  15. Hard breakup of the deuteron into two ? isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos G.; Sargsian, Misak M.

    2011-05-01

    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.

  16. Hard breakup of the deuteron into two ? -isobars

    NASA Astrophysics Data System (ADS)

    Granados, Carlos; Sargsian, Misak

    2011-04-01

    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 ?++?- 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 initial ?? components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels are expected to be similar. This work was supported by U.S. Department of Energy Grant under contract DE-FG02-01ER41172, and by the FIU DEA program.

  17. High Resolution Isobar Separator for Study of Exotic Decays

    NASA Astrophysics Data System (ADS)

    Shchepunov, V.; Piechaczek, A.; Carter, H. K.; Zganjar, E. F.; Batchelder, J.; Liddick, S. N.; Wollnik, H.; Hu, Y.

    2007-04-01

    A Multi-pass Time-Of-Flight mass spectrometer and separator (MTOF) was designed and built by the UNIRIB Consortium. The MTOF spectrometer consists of two coaxial electrostatic mirrors and auxiliary focusing, injection, and extraction elements. Ions of different mass are reflected multiple times between the mirrors and separated longitudinally. Using a test ion source, a mass resolving power of 29,000 (FWHM) has been achieved. The agreement between simulated and measured properties of the MTOF spectrometer is very good. MTOF will be converted into a mass separator by adding a fast electrostatic switch of the Bradbury-Nielson type. It will be initially coupled to the online isotope separator, UNISOR, at HRIBF to provide isobaric pure samples of exotic species in the ^100Sn region or neutron-rich nuclei for decay studies. Our ion optic calculations indicate a mass resolving power >= 15,000 and efficiencies of 30-50%. Ion optic design principles and hardware specifications from numerical simulations will be presented. The proposed RIB injection with beam cooling and bunching from the UNISOR separator into this new, compact isobar separator will be described.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  19. Neutron Star Matter Including Delta Isobars Guang-Zhou Liu1,2

    E-print Network

    Xu, Ren-Xin

    Neutron Star Matter Including Delta Isobars Guang-Zhou Liu1,2 , Wei Liu1 and En-Guang Zhao2 1 a new phase structure of neutron star matter including nucleons and delta isobars is presented. Particle fractions populated and pion condensations in neutron star matter are investgated in this model

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

    SciTech Connect

    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

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

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

    SciTech Connect

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

    2011-05-15

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

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

    NASA Astrophysics Data System (ADS)

    Plyasunov, Andrey V.

    2012-01-01

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

  3. 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

    Microsoft Academic Search

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

    2006-01-01

    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

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

    SciTech Connect

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

    1988-01-01

    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.

  5. Stars equilibrium

    NSDL National Science Digital Library

    University of Utah. Astrophysics Science Project Integrating Research and Education (ASPIRE)

    2003-01-01

    What causes the fusion reaction in a star's core? This activity page, part of an interactive laboratory series for grades 8-12, introduces students to processes inside a star. Students read about the equilibrium process in a star, in which outward gas pressure equals inward gravitational pressure. Then, an interactive lab activity offers students the opportunity to predict temperature, pressure, and gravity changes that occur during equilibrium. The chemical reactions of the fusion process are presented, and more specific detailed reactions are available in a pop-up box. Student practice quizzes about the equilibrium process and pressure and gravity interactions inside the star are included, as are answers. Copyright 2005 Eisenhower National Clearinghouse

  6. Monte Carlo simulations of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB): Pressure and temperature effects for the solid phase and vapor-liquid phase equilibria

    NASA Astrophysics Data System (ADS)

    Rai, Neeraj; Bhatt, Divesh; Siepmann, J. Ilja; Fried, Laurence E.

    2008-11-01

    The transferable potentials for phase equilibria (TraPPE) force field was extended to nitro and amino substituents for aromatic rings via parametrization to the vapor-liquid coexistence curves of nitrobenzene and aniline, respectively. These groups were then transferred to model 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Without any further parametrization to solid state data, the TraPPE force field is able to predict TATB's unit cell lengths and angles at 295K with mean unsigned percentage errors of 0.3% and 1.8% and the specific density within 0.5%. These predictions are comparable in accuracy to the GRBF model [Gee et al., J. Chem. Phys. 120, 7059 (2004)] that was parametrized directly to TATB's solid state properties. Both force fields are able to reproduce the pressure dependence of TATB's unit cell volume, but they underestimate its thermal expansion. Due to its energetic nature and unusually large cohesive energy, TATB is not chemically stable at temperature in its liquid range. Gibbs ensemble simulations allow one to determine TATB's vapor-liquid coexistence curve at elevated temperatures and the predicted critical temperature and density for the TraPPE and GRBF model are 937±8 and 1034±8K, and 0.52±0.02 and 0.50±0.02g/cm3, respectively.

  7. Monte Carlo simulations of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB): Pressure and temperature effects for the solid phase and vapor-liquid phase equilibria.

    PubMed

    Rai, Neeraj; Bhatt, Divesh; Siepmann, J Ilja; Fried, Laurence E

    2008-11-21

    The transferable potentials for phase equilibria (TraPPE) force field was extended to nitro and amino substituents for aromatic rings via parametrization to the vapor-liquid coexistence curves of nitrobenzene and aniline, respectively. These groups were then transferred to model 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Without any further parametrization to solid state data, the TraPPE force field is able to predict TATB's unit cell lengths and angles at 295 K with mean unsigned percentage errors of 0.3% and 1.8% and the specific density within 0.5%. These predictions are comparable in accuracy to the GRBF model [Gee et al., J. Chem. Phys. 120, 7059 (2004)] that was parametrized directly to TATB's solid state properties. Both force fields are able to reproduce the pressure dependence of TATB's unit cell volume, but they underestimate its thermal expansion. Due to its energetic nature and unusually large cohesive energy, TATB is not chemically stable at temperature in its liquid range. Gibbs ensemble simulations allow one to determine TATB's vapor-liquid coexistence curve at elevated temperatures and the predicted critical temperature and density for the TraPPE and GRBF model are 937+/-8 and 1034+/-8 K, and 0.52+/-0.02 and 0.50+/-0.02 gcm(3), respectively. PMID:19026069

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

    E-print Network

    Bayeh, Alexander C.

    2010-01-14

    The present work examines line measurements of pressure, temperature, and density in high speed, non-isobaric flows emanating from an underexpanded jet nozzle. Line images of rotational and vibrational Raman spectra are collected for a 8-mm linear...

  9. Isobar channels and nucleon resonances in ? + ? - electroproduction on protons

    NASA Astrophysics Data System (ADS)

    Fedotov, G. V.; Burkert, V. D.; Golovach, E. N.; Elouadrhiri, L.; Isupov, E. L.; Ishkhanov, B. S.; Mokeev, V. I.; Shvedunov, N. V.

    2008-07-01

    Acomprehensive set of differential cross sections for the reaction ? ? p ? ? - ? + p at the square of the photon 4-momentum in the range 0.2 < Q 2 < 0.6 GeV2 and the invariant mass of final-state hadrons in the range 1.3 < W < 1.6 GeV was first obtained with the CLAS detector at the Thomas Jefferson Laboratory. An analysis of these data on the basis of the phenomenological model developed by physicists from the Institute of Nuclear Physics at Moscow State University (INP MSU) and Thomas Jefferson Laboratory (INP MSU-Hall B at Jefferson Lab Collaboration) made it possible to determine, for the first time, the contributions of all isobar channels to the differential cross sections in question. The possibility of extracting the Q 2 dependences of the electromagnetic form factors for the P 11(1440) and D 13(1520) resonances in a kinematical region that is the most sensitive to the contribution of the meson-baryon cloud to the structure of nucleon resonances is demonstrated.

  10. Combining low- and high-energy tandem mass spectra for optimized peptide quantification with isobaric tags

    Microsoft Academic Search

    Loïc Dayon; Carla Pasquarello; Christine Hoogland; Jean-Charles Sanchez; Alexander Scherl

    2010-01-01

    Isobaric tagging, via TMT or iTRAQ, is widely used in quantitative proteomics. To date, tandem mass spectrometric analysis of isobarically-labeled peptides with hybrid ion trap–orbitrap (LTQ-OT) instruments has been mainly carried out with higher-energy C-trap dissociation (HCD) or pulsed q dissociation (PQD). HCD provides good fragmentation of the reporter-ions, but peptide sequence-ion recovery is generally poor compared to collision-induced dissociation

  11. Tagging of Isobars Using Energy Loss and Time-of-flight Measurements

    SciTech Connect

    Shapira, D.

    2001-11-02

    The technique for tagging isobars in a mixed beam by measuring energy loss by time-of-flight has been tested. With this method, isobar separation should improve by allowing more energy loss (thicker absorber), but only if one can control absorber homogeneity. Measurements of beam energy toss and energy spread obtained under such conditions were shown to be close to predicted values using both collisional and charge exchange contributions to energy straggling. The calculation of energy straggling allows us to study the efficacy of this method for isobar separation when applied to different mass ranges and beam energies. Separation in a most difficult case, an analyzed beam of A = 132 isobars at energies near 3 MeV/A has been demonstrated. The time-of-flight information can be added on line as an additional tag to the data stream for events of interest. Such event by event tagging enables one to study the effect of differences in isobaric mixture in the beam on the reaction outcome even when isobar separation is not complete.

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

    SciTech Connect

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

    1985-12-01

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

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

    PubMed

    Höhener, Patrick; Yu, Xianjing

    2012-03-15

    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 (13)C in groundwater pollutants in aquifers. It is also suggested that deuterium shifts are expected to be higher, especially for strongly sorbing pollutants. PMID:22055158

  14. Interference-Free Proteome Quantification with MS/MS-based Isobaric Isotopologue Detection

    PubMed Central

    2015-01-01

    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

  15. Communication: Resolving the vibrational and configurational contributions to thermal expansion in isobaric glass-forming systems

    NASA Astrophysics Data System (ADS)

    Potuzak, Marcel; Mauro, John C.; Kiczenski, T. J.; Ellison, Adam J.; Allan, Douglas C.

    2010-09-01

    A fundamental understanding of isobaric thermal expansion behavior is critical in all areas of glass science and technology. Current models of glass transition and relaxation behavior implicitly assume that the thermal expansion coefficient of glass-forming systems can be expressed as a sum of vibrational and configurational contributions. However, this assumption is made without rigorous theoretical or experimental justification. Here we present a detailed statistical mechanical analysis resolving the vibrational and configurational contributions to isobaric thermal expansion and show experimental proof of the separability of thermal expansion into vibrational and configurational components for Corning Jade® glass.

  16. Thermodynamic property representation for the R-32\\/125 binary system by a new cubic equation of state

    Microsoft Academic Search

    H.-L Zhang; H Sato; K Watanabe

    1997-01-01

    Thermodynamic properties of the R-32\\/125 binary system are modeled by a new cubic equation of state which was developed and applied to the pure R-32 and R-125 in a previous paper by the present authors. The essential thermodynamic properties such as PVTx properties, vapor-liquid equilibrium, enthalpy, entropy, isobaric specific heat, and speed of sound are well represented by the new

  17. P200-M Relative Quantification of Cerebral Spinal Fluid Proteins Utilizing Isobaric Tagging Reagents

    PubMed Central

    Guertin, S.; Gomez-Mancilla, B.; Minkoff, M.; Willetts, M.; Williamson, B.; Guerreiro, N.

    2007-01-01

    The development of isobaric tagging chemistries has permitted measurements in relative protein expression across several samples with a high degree of automation. Recently, a new set of isobaric reagents was developed that expanded the number of channels that can be processed simultaneously from four to eight. This doubling of the unique isobaric tags increases flexibility in the design of a multiplexing experiment, allowing the incorporation of a greater number of experimental samples, duplicates, or additional controls into a single pooled sample. Described herein is a method to use these reagents to measure relative protein expression across several cerebral spinal fluid (CSF) samples. Eight control and diseased CSF samples were reduced, alkylated, and each labeled with one of eight isobaric tagging reagents. After labeling, all eight samples were combined into a single pool and fractionated by cation exchange chromatography. The subsequent fractions were then analyzed by LC-MALDI on a 4800 MALDI TOF/TOF Analyzer. An analysis of the proteins identified in the CSF detailed several proteins that exhibited varying degrees of expression across the eight samples.

  18. Quantification by isobaric labeling (QUIBL) for the comparative glycomic study of O-linked glycans

    NASA Astrophysics Data System (ADS)

    Botelho, Julianne Cook; Atwood, James A., III; Cheng, Lei; Alvarez-Manilla, Gerardo; York, William S.; Orlando, Ron

    2008-12-01

    Quantification by isobaric labeling (QUIBL) has recently been described as a tool for the relative quantification of N-linked glycans in glycomic studies. In this paper we expand the application of QUIBL to the relative quantification of O-linked glycans. Fetuin, which contains two O-linked glycans, NeuAc-Hex-HexNAc and NeuAc2-Hex-HexNAc, was used to validate this studyE The glycans were released by [beta]-elimination and permethylated with the isobaric labeling reagents, 13CH3I and 12CH2DI. The exact mass difference between the isobaric labels is minimal (0.00292 Da), but since glycans contain multiple permethylation sites, the mass difference can be resolved with a high resolution mass spectrometer, such as an FTMS. Quantitative data were obtained by comparing the signal intensities from various mixtures of isobarically labeled O-linked glycans of fetuin. Five different ratios of 13CH3 to 12CH2D ranging from 10:1 to 1:10 were analyzed for linearity and reproducibility of the QUIBL method on the standard glycan. QUIBL was also evaluated using porcine mucin, a sample with a larger variety of more complex O-linked glycans. These results indicate that QUIBL allows for the relative quantification of O-linked glycans over a linear dynamic range of at least two orders of magnitude, validating QUIBL as an applicable quantitative glycomics approach for both N-linked and O-linked glycans.

  19. EQUILIBRIUM Dr. Stephen Thompson

    E-print Network

    Hardy, Darel

    Reactants And Products 12 Plotting Equilibrium Constants 13 Plotting Equilibrium Constants 14 Calculating Equilibrium Constants 15 Le Chatelier's Principle 16 Le Chatelier's Principle 17 Temperature And Equilibrium molecules in the air and the size of the drop become constant. At this point, we have reached EQUILIBRIUM

  20. Comparative study of intrathecal hyperbaric versus isobaric ropivacaine: A randomized control trial

    PubMed Central

    Gupta, Rajni; Bogra, Jaishri; Singh, Prithvi Kumar; Saxena, Sulekha; Chandra, Girish; Kushwaha, Jitendra Kumar

    2013-01-01

    Background: Hyperbaric ropivacaine produce more reliable sensory and motor block, with faster onset, better quality of muscles relaxation than isobaric ropivacaine. So, this study was designed to compare the efficacy of hyperbaric ropivacaine with isobaric ropivacaine in patients undergoing lower abdominal surgery. Methods: A randomized controlled double blind study in two groups of patients. group A (n=35) received 3 ml of isobaric ropivacaine 6 mg/ml (18 mg). Group B (n=35) received 3 ml of hyperbaric ropivacaine 6 mg/ml (18 mg). The onset and duration of sensory block at dermatome level T10, maximum upper and lower spread of sensory block, intensity, and duration of motor block were recorded. Statistical Analysis: Block characteristics were compared using the two-tailed Mann – Whitney U-test. The proportion of side effects was compared using the Chi-square test. Results: The median time of onset of sensory block at the T10 dermatome was 4.4±1.3 min in group B and 6.0±1.03 min in group A. The median time to maximum block height was 16.7±3.7 min in group A and 12.03±1.96 min in group B. The median duration of complete motor recovery (B0) was significantly shorter in the heavy ropivacaine group (166.5±11.7 min) compared with the isobaric ropivacaine group (192.9±9.6 min). Conclusions: Intrathecal hyperbaric ropivacaine provides more rapid, adequate, and good quality of sensory and motor block with rapid post-operative recovery as compare to isobaric ropivacaine. PMID:24015125

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

    E-print Network

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

    2012-12-16

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

  2. Electrical properties of MOS structures based on 3C-SiC(111) epilayers grown by Vapor-Liquid-Solid Transport and Chemical-Vapor Deposition on 6H-SiC(0001)

    NASA Astrophysics Data System (ADS)

    Esteve, R.; Lorenzzi, J.; Reshanov, S. A.; Jegenyes, N.; Schöner, A.; Ferro, G.; Zetterling, C.-M.

    2010-11-01

    The electrical properties of post-oxidized PECVD oxides in wet oxygen based on 3C-SiC(111) epilayers grown by Vapor-Liquid-Solid and Chemical-Vapor-Deposition mechanisms on 6H-SiC(0001) have been studied. Different 6H-SiC(0001) samples exhibiting diverse crystal orientations (on-axis, 2° off-axis) and growth conditions were regarded. A comparative study of oxide qualities has been carried out via capacitance and conductance measurements (C-G-V). Achieved interface traps densities and effective oxide charges were compared for the different samples. Reliability issues have been considered via current measurements (I-V and TZDB) and statistical data treatment techniques (Weibull plots). Oxides based on 3C-SiC layer grown by a process combining VLS and CVD methods demonstrated low interface states densities Dit of 1.2×1010eV-1cm-2 at 0.63 eV below the conduction band and fixed oxide charges Qeff/q estimated to -0.1×1011 cm-2.

  3. The TRK-sum rule in 4He including isobar effects

    Microsoft Academic Search

    W. Heinze; H. Arenhövel; G. Horlacher

    1978-01-01

    The TRK-sum rule has been reevaluated for 4He and an enhancement of about 90 per cent has been found confirming the earlier evaluation of Weng et al. It is not so sensitively dependent on details of the correlation functions. One- and two-Delta isobar configurations in 4He contribute about one additional classical sum rule. Supported by the Deutsche Froschungsgemeinschaft, contract Eh

  4. Multiplexed Protein Quantitation in Saccharomyces cerevisiae Using Amine-reactive Isobaric Tagging Reagents

    Microsoft Academic Search

    Philip L. Ross; Yulin N. Huang; Jason N. Marchese; Brian Williamson; Kenneth Parker; Stephen Hattan; Nikita Khainovski; Sasi Pillai; Subhakar Dey; Scott Daniels; Subhasish Purkayastha; Peter Juhasz; Stephen Martin; Michael Bartlet-Jones; Feng He; Allan Jacobson; Darryl J. Pappin

    2004-01-01

    We describe here a multiplexed protein quantitation strat- egy that provides relative and absolute measurements of proteins in complex mixtures. At the core of this method- ology is a multiplexed set of isobaric reagents that yield amine-derivatized peptides. The derivatized peptides are indistinguishable in MS, but exhibit intense low-mass MS\\/MS signature ions that support quantitation. In this study, we have

  5. Possible enhancement of magnetic dipole transitions between Gamow-Teller and isobaric analog states

    Microsoft Academic Search

    H. Sagawa; Toshio Suzuki; Nguyen van Giai

    1995-01-01

    A new decay scheme between Gamow-Teller (GT) resonances and isobaric analog states (IAS) by magnetic dipole transitions is studied. The sum rule of M1 transitions between IAS and GT states is found to be significantly enhanced compared to the non-energy-weighted sum rule of the parent state. Calculated enhancement factors can be as large as ~2.5 for 48Sc and 90Nb, and

  6. Relativistic RPA for Isobaric Analogue and Gamow-Teller Resonances in Closed Shell Nuclei

    E-print Network

    C. De Conti; A. P. Galeao; F. Krmpotic

    1998-10-30

    We perform a self-consistent relativistic RPA calculation for the isobaric analogue and Gamow-Teller resonances based on relativistic mean field theory results for the ground states of $^{48}$Ca, $^{90}$Zr and $^{208}$Pb. We use the parameter set NL1 for the $\\sigma$, $\\omega$ and $\\rho$ mesons, and experimental values for the pion and nucleon. An extra parameter, related to the intensity of the contact term in the pion-exchange interaction, is crucial to reproduce the latter resonances.

  7. Enhanced sample multiplexing for nitrotyrosine-modified proteins using combined precursor isotopic labeling and isobaric tagging.

    PubMed

    Robinson, Renã A S; Evans, Adam R

    2012-06-01

    Current strategies for identification and quantification of 3-nitrotyrosine (3NT) post-translationally modified proteins (PTM) generally rely on biotin/avidin enrichment. Quantitative approaches have been demonstrated which employ isotopic labeling or isobaric tagging in order to quantify differences in the relative abundances of 3NT-modified proteins in two or potentially eight samples, respectively. Here, we present a novel strategy which uses combined precursor isotopic labeling and isobaric tagging (cPILOT) to increase the multiplexing capability of quantifying 3NT-modified proteins to 12 or 16 samples using commercially available tandem mass tags (TMT) or isobaric tags for relative and absolute quantification (iTRAQ), respectively. This strategy employs "light" and "heavy" labeled acetyl groups to block both N-termini and lysine residues of tryptic peptides. Next, 3NT is reduced to 3-aminotyrosine (3AT) using sodium dithionite followed by derivatization of light and heavy labeled 3AT-peptides with either TMT or iTRAQ multiplex reagents. We demonstrate the proof-of-principle utility of cPILOT with in vitro nitrated bovine serum albumin (BSA) and mouse splenic proteins using TMT(0), TMT(6), and iTRAQ(8) reagents and discuss limitations of the strategy. PMID:22509719

  8. Combining low- and high-energy tandem mass spectra for optimized peptide quantification with isobaric tags.

    PubMed

    Dayon, Loïc; Pasquarello, Carla; Hoogland, Christine; Sanchez, Jean-Charles; Scherl, Alexander

    2010-02-10

    Isobaric tagging, via TMT or iTRAQ, is widely used in quantitative proteomics. To date, tandem mass spectrometric analysis of isobarically-labeled peptides with hybrid ion trap-orbitrap (LTQ-OT) instruments has been mainly carried out with higher-energy C-trap dissociation (HCD) or pulsed q dissociation (PQD). HCD provides good fragmentation of the reporter-ions, but peptide sequence-ion recovery is generally poor compared to collision-induced dissociation (CID). Herein, we describe an approach where CID and HCD spectra are combined. The approach ensures efficiently both identification and relative quantification of proteins. Tandem mass tags (TMTs) were used to label digests of human plasma and LC-MS/MS was performed with an LTQ-OT instrument. Different HCD collision energies were tested. The benefits to use CID and HCD with respect to HCD alone were demonstrated in terms of number of identifications, subsequent number of quantifiable proteins, and quantification accuracy. A program was developed to merge the peptide sequence-ion m/z range from CID spectra and the reporter-ion m/z range from HCD spectra, and alternatively to separate both spectral data into different files. As parallel CID in the LTQ almost doesn't affect the analysis duty cycle, the procedure should become a standard for quantitative analyses of proteins with isobaric tagging using LTQ-OT instruments. PMID:19903544

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

    PubMed Central

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

    2013-01-01

    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

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

    SciTech Connect

    Elizondo-Villarreal, E.M.

    1989-01-01

    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.

  11. Chapman Cycle Equilibrium Calculator

    NSDL National Science Digital Library

    The Shodor Education Foundation, Inc.

    The Chapman Cycle Equilibrium Calculator solves for the equilibrium solution of the chemical reactions in the Chapman Cycle, assuming a solar flux equivalent to that at the top of the Earth's atmosphere. A Newton-Rhapson method is used to find the solution, which requires an initial guess as to the equilibrium solution.

  12. Isobaric tagging-based selection and quantitation of cerebrospinal fluid tryptic peptides with reporter calibration curves.

    PubMed

    Dayon, Loïc; Turck, Natacha; Kienle, Stefan; Schulz-Knappe, Peter; Hochstrasser, Denis F; Scherl, Alexander; Sanchez, Jean-Charles

    2010-02-01

    In the past few years, mass spectrometry (MS) has emerged as an efficient tool for the multiplexed peptide and protein concentration determination by isotope dilution. Despite the growing use of isobaric tagging to perform relative quantitation for the discovery of potential biomarkers in biological fluids, no real application has so far been presented for their absolute quantitation. Isobaric tandem mass tags (TMTs) were used herein for the selection and quantitation of tryptic peptides derived from brain damage related proteins in cerebrospinal fluid (CSF). Proteotypic tryptic peptide analogues were synthesized, prepared in four reference amounts, differentially labeled with four isobaric TMTs with reporter-ions at m/z = 128.1, 129.1, 130.1, and 131.1, and mixed with CSF sample previously labeled with TMT 126.1. Off-gel electrophoresis (OGE) was used as first-dimension separation of the pooled sample. The resulting fractions were analyzed with reversed-phase liquid chromatography (RP-LC) tandem mass spectrometry (MS/MS), using tandem time-of-flight (TOF/TOF) and hybrid linear ion trap-orbitrap (LTQ-OT) instruments. Under collision-induced dissociation (CID) or higher-energy C-trap dissociation (HCD), the release of the reporter fragments from the TMT-labeled peptide standards provided an internal calibration curve to assess the concentration of these peptides in the CSF. This tool also allowed identifying selectively these peptides in CSF as only the targeted peptides showed specific fragmentation pattern in the TMT reporter-ion zone of the tandem mass spectra. Assays for the concentration measurements of peptides from PARK7, GSTP1, NDKA, and S100B proteins in CSF were further characterized using this novel, efficient, and straightforward approach. PMID:20058875

  13. Isobaric thermal expansivity and isothermal compressibility of several nonsaturated hydrocarbons at 298.15 K

    SciTech Connect

    Aicart, E.; Junquera, E. [Univ. Complutense, Madrid (Spain). Dept. de Quimica Fisica I; Letcher, T.M. [Univ. of Natal, Durban (South Africa)

    1995-11-01

    The isobaric thermal expansivity and the isothermal compressibility have been measured at 298.15 K for several nonsaturated hydro bons: 1-hexene, 1-hexyne, 1-heptene, 1-heptyne, 1-octene, 1-octyne, o-xylene, m-xylene, p-xylene, and mesitylene (1,3,5-trimethylbenzene). The results, together with previous data from their laboratory, are discussed in terms of the chain length of the hydrocarbons, the degree of unsaturation (-ane, -ene, -yne), the degree of methylation, and the position of the methyl groups on the aromatic ring.

  14. Electric and magnetic response to the continuum for A=7 isobars in a dicluster model

    E-print Network

    A. Mason; R. Chatterjee; L. Fortunato; A. Vitturi

    2008-11-11

    Mirror isobars $^7$Li and $^7$Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole excitations even at astrophysical energies, at a variance with the case of deuteron. Energy weighted molecular sum rules are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations. Cross-sections for photo-dissociation and radiative capture as well as the S-factor for reactions of astrophysical significance are calculated with good agreement with known experimental data.

  15. Relativistic description of (p,n) reactions to the isobaric analog state

    NASA Astrophysics Data System (ADS)

    Clark, B. C.; Hama, S.; Sugarbaker, E.; Franey, M. A.; Mercer, R. L.; Ray, L.; Hoffmann, G. W.; Serot, B. D.

    1984-07-01

    Lorentz vector and scalar, isovector and isoscalar proton-nucleus optical potentials are obtained from invariant nucleon-nucleon amplitudes using a relativistic impulse approximation. Cross sections, analyzing powers, and spin rotation functions for 90Zr(p,p) and the 90Zr(p,n)90Nb (isobaric analog state) reaction at 160 and 500 MeV are calculated using a relativistic generalization of the Lane equations. These predictions are compared to nonrelativistic impulse approximation results and to experimental data at 160 MeV.

  16. A Pressure Diagnostic Based on X-Ray Continuum Images of Compressed Isobaric Hydrogen Implosion Cores

    NASA Astrophysics Data System (ADS)

    Epstein, R.; Marshall, F. J.; Goncharov, V. N.; Betti, R.; Nora, R.; Christopherson, A. R.; Golovkin, I. E.; Macfarlane, J. J.

    2013-10-01

    Pressure is the quantity that best characterizes isobaric implosion cores, and it is a key parameter in quantifying their near-ignition performance. At high spectral energy, where the free-free (FF) emission from an imploded hydrogen core is optically thin, the FF emissivity profile can be obtained from an image by Abel inversion. This emissivity, which can be modeled accurately under hot-core conditions, is strongly temperature and density dependent. With a spectral response function matched to the temperature range anticipated for the hot spot at the time of peak emission, however, the imaged intensity becomes a function of the core pressure profile with very weak temperature dependence. In this way, the measured FF emissivity profile becomes a direct measure of the core pressure profile at the time of peak emission, as well as a test of the isobaric assumption. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  17. iFASP: Combining Isobaric Mass Tagging with Filter-Aided Sample Preparation

    PubMed Central

    McDowell, Gary S.; Gaun, Aleksander; Steen, Hanno

    2015-01-01

    Careful, clean and controlled preparation of samples for mass spectrometry proteomics is crucial to obtain reproducible and reliable data. This is especially important when carrying out quantitative proteomics by chemical isobaric labeling (aka tandem mass tagging) since the differentially labeled samples are combined quite late during the sample processing. Addressing this need for robust and reliable sample processing for quantitative proteomics, we describe here iFASP, a simple protocol for combining isobaric mass tagging with the recently introduced Filter-Aided Sample Preparation (FASP) method. iFASP provides a quick, simple and effective method for obtaining clean samples, ensuring efficient digestion and providing excellent labeling yields for quantitative proteomics experiments. We have carried out our iFASP protocol using several highly complex Xenopus laevis egg and embryo lysates and compared the labeling yields and number of high-confidence peptide identifications to a standard in-solution digestion and labeling protocol. Although the labeling efficiency with both techniques is in the 99+% range, the number of peptides identified with a 1% false discovery rate and the corresponding number of quantified peptide spectral matches are as much as doubled with iFASP compared to the corresponding non-FASP-based method. PMID:23692318

  18. IsobarPTM: A software tool for the quantitative analysis of post-translationally modified proteins?

    PubMed Central

    Breitwieser, Florian P.; Colinge, Jacques

    2013-01-01

    The establishment of extremely powerful proteomics platforms able to map thousands of modification sites, e.g. phosphorylations or acetylations, over entire proteomes calls for equally powerful software tools to effectively extract useful and reliable information from such complex datasets. We present a new quantitative PTM analysis platform aimed at processing iTRAQ or Tandem Mass Tags (TMT) labeled peptides. It covers a broad range of needs associated with proper PTM ratio analysis such as PTM localization validation, robust ratio computation and statistical assessment, and navigable user report generation. IsobarPTM is made available as an R Bioconductor package and it can be run from the command line by non R specialists. Biological significance “IsobarPTM is a new software tool facilitating the quantitative analysis of protein modification regulation streamlining important issues related to PTM localization and statistical modeling. Users are provided with a navigable spreadsheet report, which also annotate already public modification sites.” This article is part of a Special Issue entitled: From Genome to Proteome: Open Innovations. PMID:23470796

  19. Isobaric yield ratios and the symmetry energy in heavy-ion reactions near the Fermi energy

    SciTech Connect

    Huang, M. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Z. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Kowalski, S. [Institute of Physics, Silesia University, Katowice (Poland); Ma, Y. G. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Wada, R.; Hagel, K.; Barbui, M.; Bottosso, C.; Materna, T.; Natowitz, J. B.; Qin, L.; Rodrigues, M. R. D.; Sahu, P. K. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Keutgen, T. [FNRS and IPN, Universite Catholique de Louvain, B-1348 Louvain-Neuve (Belgium); Bonasera, A. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Laboratori Nazionali del Sud, INFN, via Santa Sofia, 62, 95123 Catania (Italy); Wang, J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2010-04-15

    The relative isobaric yields of fragments produced in a series of heavy-ion-induced multifragmentation reactions have been analyzed in the framework of a modified Fisher model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, a{sub sym}/T, as a function of fragment mass A. The extracted values increase from 5 to approx16 as A increases from 9 to 37. These values have been compared to the results of calculations using the antisymmetrized molecular dynamics (AMD) model together with the statistical decay code gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the values extracted from the ratios of the primary isobars from the AMD model calculation are approx4 to 5 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.

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

    E-print Network

    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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  3. [Comparison of isobaric effects of hypertension and diabetes mellitus on geometric and elastic properties of human arteries].

    PubMed

    Mégnien, J L; Simon, A; Valensi, P; Pithois-Merli, I; Assad, N; Attali, J; Levenson, J

    1991-08-01

    Hypertensive and diabetic mellitus diseases are known to increase stiffness of the arterial wall. However these alterations probably involve different mechanisms. To this end, we compared the effect of hypertension and diabetes on large artery caliber and elasticity at real pressure conditions and at the same level of pressure. Nine poorly controlled non insulino-dependent diabetic men without hypertension and 9 non-diabetic essential hypertensive men underwent measures of lumen diameter (pulsed Doppler) and segmental compliance (Bramwell and Hill formula; pulse wave velocity) at the brachial artery. Isobaric diameter and compliance were deduced from a non linear model, comparing diameter and pressure on one part, and compliance and pressure on the other. Pulse wave velocity was similarly increased in both diseases (11.5 +/- 1 vs 12.8 +/- 1 m/s; NS; respectively in diabetes and hypertension). Both measured and isobaric diameters were smaller in diabetic patients (4.05 +/- 0.2 vs 5.03 +/- 0.2 mm, p less than 0.1% for the measured diameters respectively in diabetes and hypertension and 4.06 +/- 0.2 vs 5.01 +/- 0.2 mm, p less than 1% for isobaric diameters). The measured and isobaric compliances were not significantly different (2.38 +/- 0.4 vs 2.08 +/- 0.2 cm/mmHg10(-4), NS, for the measured compliance respectively in diabetes and hypertension; 2.28 +/- 0.4 vs 2.4 +/- 0.2, NS for the isobaric compliance). After correction of the effect of mechanical arterial stretch induced by the different blood pressure level of the two groups, significant reduction of diameter in diabetic subjects persisted and isobaric and measured compliances remained unchanged between groups. PMID:1953257

  4. Equilibrium and volumetric data and model development for coal fluids. Final report, October 1, 1990--September 30, 1993

    SciTech Connect

    Robinson, R.L. Jr.; Gasem, K.A.M.; Park, J.; Tong, J.; Shaver, R.D.; Bader, M.S.; Twomey, D.W.

    1994-03-03

    Under continued support from DOE, an experimental facility has been established and operated to measure valuable vapor-liquid equilibrium data for systems of interest in the production and processing of coal fluids. To facilitate the development and testing of models for predicting the phase behavior for such systems, we have acquired substantial amounts of data on the equilibrium phase compositions for binary mixtures of heavy hydrocarbon solvents with the supercritical solutes hydrogen, methane, ethane, CO, and CO{sub 2}. During the course of this project, solubility data were obtained on twenty-two binary mixtures of CO, hydrogen, or nitrogen in a series of paraffinic, naphthenic and aromatic solvents (decane, eicosane, octacosane, hexatriacontane, cyclohexane, decalin, benzene, naphthalene, phenanthrene, pyrene). The measurements were conducted at temperatures from 310 to 433 K, pressures to 22 MPa, and solute mole fraction from 0.01 to 0.30. Estimated errors of the measured gas solubilities in the selected solvents are less than 0.001. Specific accomplishments of this project included (a) upgrading our experimental facility to permit highly accurate measurements of equilibrium phase compositions (solubilities) and phase densities; (b) measuring these properties for systematically-selected binary mixtures to provide critically needed input data for correlation development; (c) developing and testing models suitable for describing the phase behavior of coal-fluid mixtures, and the modeling results in generalized, practical formats suitable for use in process engineering calculations.

  5. Misconceptions of chemical equilibrium

    Microsoft Academic Search

    Mark W. Hackling; Patrick J. Garnett

    1985-01-01

    Those propositions deemed necessary for an understanding of chemical equilibrium and Le Chatelier's Principle were defined by the investigators and validated.Thirty, Year 12 Western Australian chemistry students (17 years of age) who had studied chemical equilibrium were interviewed and students’ responses were coded into various categories of misconception that had been identified. The most significant misconceptions revealed by the study

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

    E-print Network

    Baldick, Ross

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

  7. Neutron Density Distributions of Neutron-Rich Nuclei Studied with the Isobaric Yield Ratio Difference

    E-print Network

    Chun-Wang Ma; Xiao-Man Bai; Jiao Yu; Hui-Ling Wei

    2014-09-09

    The isobaric yield ratio difference (IBD) between two reactions of similar experimental setups is found to be sensitive to nuclear density differences between projectiles. In this article, the IBD probe is used to study the density variation in neutron-rich $^{48}$Ca. By adjusting diffuseness in the neutron density distribution, three different neutron density distributions of $^{48}$Ca are obtained. The yields of fragments in the 80$A$ MeV $^{40, 48}$Ca + $^{12}$C reactions are calculated by using a modified statistical abrasion-ablation model. It is found that the IBD results obtained from the prefragments are sensitive to the density distribution of the projectile, while the IBD results from the final fragments are less sensitive to the density distribution of the projectile.

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

    SciTech Connect

    Boswell, M. S. [Physics Division, Los Alamos National Laboratory, NM (United States); Young, A. R. [Physics Department, North Carolina State University, Raleigh, NC (United States); Ejiri, H. [RCNP, Osaka University, Osaka, 567-0047 (Japan) and Nuclear Science, Czech Technical University, Brehova, Prague (Czech Republic)

    2013-04-19

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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.

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

    PubMed

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

    2013-12-27

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

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

    NASA Technical Reports Server (NTRS)

    Lambertsen, C. J.; Idicula, J.

    1975-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  13. Zr-Nb isobar separation experiments for future 93Zr AMS

    NASA Astrophysics Data System (ADS)

    Lu, Wenting; Collon, P.; Kashiv, Y.; Bowers, M.; Robertson, D.; Schmitt, C.

    2013-01-01

    AMS detection of the rare isotope 93Zr (t1/2 = 1.6 Ma) has application potential in two fields of research: a better determination of the 92Zr(n,?)93Zr cross section, which is relevant in astrophysical modeling of nucleosynthesis processes, and using this radionuclide as tracer in hydrological and radioactive waste studies. The biggest challenge in measuring 93Zr at natural concentrations is adequate separation from its stable isobar 93Nb. The Nuclear Science Laboratory at the University of Notre Dame is developing the capability to measure 93Zr by AMS. Results are reported of first experiments, featuring the combination of a gas-filled magnet with a position-sensitive Parallel Grid Avalanche Counter and a Gas Ionization chamber in this magnet’s focal-plane.

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

    SciTech Connect

    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

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2009-11-01

    Masses of the radionuclides Si32,33 and P34 and of the stable nuclides S32 and P31 have been measured with the Low Energy Beam and Ion Trap (LEBIT) Penning trap mass spectrometer. Relative mass uncertainties as low as 3×10-9 have been achieved. The measured mass value of Si32 differs from the literature value by four standard deviations. The precise mass determination of Si32 and S32 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.

  16. Double-? transformations in isobaric triplets with mass numbers A=124, 130, and 136

    NASA Astrophysics Data System (ADS)

    Nesterenko, D. A.; Blaum, K.; Block, M.; Droese, C.; Eliseev, S.; Herfurth, F.; Minaya Ramirez, E.; Novikov, Yu. N.; Schweikhard, L.; Shabaev, V. M.; Smirnov, M. V.; Tupitsyn, I. I.; Zuber, K.; Zubova, N. A.

    2012-10-01

    The Q values of double-electron capture in 124Xe, 130Ba, and 136Ce and double-beta decay of 124Sn and 130Te have been determined with the Penning-trap mass spectrometer SHIPTRAP with a few hundred eV uncertainty. These nuclides are members of three isobaric triplets with common daughter nuclides. The main goal of this work was to investigate the existence of the resonant enhancement of the neutrinoless double-electron-capture rates in 124Xe and 130Ba in order to assess their suitability for the search for neutrinoless double-electron capture. Based on our results, in neither of these cases is the resonance condition fulfilled.

  17. Chemical Principles Revisited: Chemical Equilibrium.

    ERIC Educational Resources Information Center

    Mickey, Charles D.

    1980-01-01

    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)

  18. N, N-Dimethyl Leucines as Novel Isobaric Tandem Mass Tags for Quantitative Proteomics and Peptidomics

    PubMed Central

    Xiang, Feng; Ye, Hui; Chen, Ruibing; Fu, Qiang; Li, Lingjun

    2010-01-01

    Herein we describe the development and application of a set of novel N, N-dimethyl leucine (DiLeu) 4-plex isobaric tandem mass (MS2) tagging reagents with high quantitation efficacy and greatly reduced cost for neuropeptide and protein analysis. DiLeu reagents serve as attractive alternatives for isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tags (TMTs) due to their synthetic simplicity, labeling efficiency and improved fragmentation efficiency. DiLeu reagent resembles the general structure of a tandem mass tag in that it contains an amine reactive group (triazine ester) targeting the N-terminus and ?-amino group of the lysine side-chain of a peptide, a balance group, and a reporter group. A mass shift of m/z 145.1 is observed for each incorporated label. Intense a1 reporter ions at m/z 115.1, 116.1, 117.1, and 118.1 are observed for all pooled samples upon MS2. All labeling reagents are readily synthesized from commercially available chemicals with greatly reduced cost. Labels 117 and 118 can be synthesized in one step and labels 115 and 116 can be synthesized in two steps. Both DiLeu and iTRAQ reagents show comparable protein sequence coverage (~43%) and quantitation accuracy (<15%) for tryptically digested protein samples. Furthermore, enhanced fragmentation of DiLeu labeling reagents offers greater confidence in protein identification and neuropeptide sequencing from complex neuroendocrine tissue extracts from a marine model organism, Callinectes sapidus. PMID:20218596

  19. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

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

  20. Lecture Ch. 4a Equilibrium

    E-print Network

    Russell, Lynn

    · Chemical equilibrium Chemical Equilibrium · Two phases in equilibrium ­ Constant T, P · Phase changes1 Lecture Ch. 4a · Equilibrium · Phase changes · Enthalpy changes from phase changes ­ Latent heat with more than one chemical component, there are more than 2 independent variables; if more than one phase

  1. Effect of spinal anesthesia for elective cesarean section on cerebral blood oxygenation changes: comparison of hyperbaric and isobaric bupivacaine.

    PubMed

    Kondo, Yuko; Sakatani, Kaoru; Hirose, Noriya; Maeda, Takeshi; Kato, Jitsu; Ogawa, Setsuro; Katayama, Yoichi

    2013-01-01

    We used near-infrared spectroscopy (NIRS) to evaluate cerebral blood oxygenation changes in subjects undergoing cesarean section under spinal anesthesia (SP) with hyperbaric bupivacaine (group H, 27 subjects) or isobaric bupivacaine (group I, 15 subjects). In group H, total-Hb, oxy-Hb, and mean blood pressure (MBP) within 20 min after SP were significantly lower than the baseline values. In contrast, there was no significant change from baseline in total-Hb, oxy-Hb, or MBP in group I after SP. Total-Hb and MBP in group H were significantly lower than those in group I within 10 min after SP. There was no significant change of deoxy-Hb, tissue oxygen index, or heart rate from baseline in either of the groups. These results suggest that isobaric bupivacaine may be superior to hyperbaric bupivacaine for preventing a decrease of maternal cerebral blood flow after SP for cesarean section. PMID:22879022

  2. Direct atmospheric pressure chemical ionisation ion trap mass spectrometry for aroma analysis: Speed, sensitivity and resolution of isobaric compounds

    NASA Astrophysics Data System (ADS)

    Jublot, Lionel; Linforth, Robert S. T.; Taylor, Andrew J.

    2005-06-01

    Atmospheric pressure chemical ionisation (APCI) sources were developed for real time analysis of volatile release from foods using an ion trap (IT) mass spectrometer (MS). Key objectives were spectral simplicity (minimal fragmentation), response time and signal to noise ratio. The benefits of APCI-IT-MS were assessed by comparing the performance for in vivo and headspace analyses with that obtained using APCI coupled to a quadrupole mass analyser. Using MS-MS, direct APCI-IT-MS was able to differentiate mixtures of some C6 and terpene isobaric aroma compounds. Resolution could be achieved for some compounds by monitoring specific secondary ions. Direct resolution was also achieved with two of the three isobaric compounds released from chocolate with time as the sample was eaten.

  3. Improved Isobaric Tandem Mass Tag Quantification by Ion Mobility-Mass Spectrometry

    PubMed Central

    Li, Lingjun

    2014-01-01

    Isobaric tandem mass tags are an attractive alternative to mass difference tags and label free approaches for quantitative proteomics due to the high degree of multiplexing that can be performed with their implementation. A drawback of tandem mass tags are that the co-isolation and co-fragmentation of labeled peptide precursors can result in chimeric MS/MS spectra that can underestimate the fold-change expression of each peptide. Two methods (QuantMode and MS3) have addressed this concern for ion trap and orbitrap instruments, but there is still a need to solve this problem for quadrupole time-of-flight (Q-TOF) instruments. Ion mobility (IM) separations coupled to Q-TOF instruments have the potential to mitigate MS/MS spectra chimeracy since IM-MS has the ability to separate ions based on charge, m/z, and collision cross section (CCS). This work presents results that showcase the power of IM-MS to improve tandem mass tag peptide quantitation accuracy by resolving co-isolated differently charged and same charged peptides prior to MS/MS fragmentation. PMID:24677527

  4. Combining Amine Metabolomics and Quantitative Proteomics of Cancer Cells Using Derivatization with Isobaric Tags

    PubMed Central

    2015-01-01

    Quantitative metabolomics and proteomics technologies are powerful approaches to explore cellular metabolic regulation. Unfortunately, combining the two technologies typically requires different LC-MS setups for sensitive measurement of metabolites and peptides. One approach to enhance the analysis of certain classes of metabolites is by derivatization with various types of tags to increase ionization and chromatographic efficiency. We demonstrate here that derivatization of amine metabolites with tandem mass tags (TMT), typically used in multiplexed peptide quantitation, facilitates amino acid analysis by standard nanoflow reversed-phase LC-MS setups used for proteomics. We demonstrate that this approach offers the potential to perform experiments at the MS1-level using duplex tags or at the MS2-level using novel 10-plex reporter ion-containing isobaric tags for multiplexed amine metabolite analysis. We also demonstrate absolute quantitative measurements of amino acids conducted in parallel with multiplexed quantitative proteomics, using similar LC-MS setups to explore cellular amino acid regulation. We further show that the approach can also be used to determine intracellular metabolic labeling of amino acids from glucose carbons. PMID:24611633

  5. The multiscale coarse-graining method. V. Isothermal-isobaric ensemble

    NASA Astrophysics Data System (ADS)

    Das, Avisek; Andersen, Hans C.

    2010-04-01

    The multiscale coarse-graining (MS-CG) method is a method for determining the effective potential energy function for a coarse-grained (CG) model of a system using the data obtained from molecular dynamics simulation of the corresponding atomically detailed model. The MS-CG method, as originally formulated for systems at constant volume, has previously been given a rigorous statistical mechanical basis for the canonical ensemble. Here, we propose and test a version of the MS-CG method suitable for the isothermal-isobaric ensemble. The method shows how to construct an effective potential energy function for a CG system that generates the correct volume fluctuations as well as correct distribution functions in the configuration space of the CG sites. The formulation of the method requires introduction of an explicitly volume dependent term in the potential energy function of the CG system. The theory is applicable to simulations with isotropic volume fluctuations and cases where both the atomistic and CG models do not have any intramolecular constraints, but it is straightforward to extend the theory to more general cases. The present theory deals with systems that have short ranged interactions. (The extension to Coulombic forces using Ewald methods requires additional considerations.) We test the theory for constant pressure MS-CG simulations of a simple model of a solution. We show that both the volume dependent and the coordinate dependent parts of the potential are transferable to larger systems than the one used to obtain these potentials.

  6. Proteomic analysis of astrocytic secretion that regulates neurogenesis using quantitative amine-specific isobaric tagging

    SciTech Connect

    Yan, Hu; Zhou, Wenhao [Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China)] [Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China); Wei, Liming; Zhong, Fan [Institutes of Biomedical Sciences, Fudan University, 138 Yixueyuan Roda, Shanghai 200032 (China)] [Institutes of Biomedical Sciences, Fudan University, 138 Yixueyuan Roda, Shanghai 200032 (China); Yang, Yi, E-mail: yyang@shmu.edu.cn [Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China)] [Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai 201102 (China)

    2010-01-08

    Astrocytes are essential components of neurogenic niches that affect neurogenesis through membrane association and/or the release of soluble factors. To identify factors released from astrocytes that could regulate neural stem cell differentiation and proliferation, we used mild oxygen-glucose deprivation (OGD) to inhibit the secretory capacity of astrocytes. Using the Transwell co-culture system, we found that OGD-treated astrocytes could not promote neural stem cell differentiation and proliferation. Next, isobaric tagging for the relative and absolute quantitation (iTRAQ) proteomics techniques was performed to identify the proteins in the supernatants of astrocytes (with or without OGD). Through a multi-step analysis and gene ontology classification, 130 extracellular proteins were identified, most of which were involved in neuronal development, the inflammatory response, extracellular matrix composition and supportive functions. Of these proteins, 44 had never been reported to be produced by astrocytes. Using ProteinPilot software analysis, we found that 60 extracellular proteins were significantly altered (27 upregulated and 33 downregulated) in the supernatant of OGD-treated astrocytes. Among these proteins, 7 have been reported to be able to regulate neurogenesis, while others may have the potential to regulate neurogenesis. This study profiles the major proteins released by astrocytes, which play important roles in the modulation of neurogenesis.

  7. Isobar channels and nucleon resonances in {pi}{sup +{pi}-} electroproduction on protons

    SciTech Connect

    Fedotov, G. V., E-mail: fedotov@depni.sinp.msu.r [Moscow State University (Russian Federation); Burkert, V. D. [Thomas Jefferson National Accelerator Facility (United States); Golovach, E. N. [Moscow State University (Russian Federation); Elouadrhiri, L. [Thomas Jefferson National Accelerator Facility (United States); Isupov, E. L.; Ishkhanov, B. S. [Moscow State University (Russian Federation); Mokeev, V. I. [Thomas Jefferson National Accelerator Facility (United States); Shvedunov, N. V. [Moscow State University (Russian Federation)

    2008-07-15

    Acomprehensive set of differential cross sections for the reaction {gamma}{sub {nu}p} {sup {yields} {pi}-{pi}+}p at the square of the photon 4-momentum in the range 0.2 < Q{sup 2} < 0.6 GeV{sup 2} and the invariant mass of final-state hadrons in the range 1.3 < W < 1.6 GeV was first obtained with the CLAS detector at the Thomas Jefferson Laboratory. An analysis of these data on the basis of the phenomenological model developed by physicists from the Institute of Nuclear Physics at Moscow State University (INP MSU) and Thomas Jefferson Laboratory (INP MSU-Hall B at Jefferson Lab Collaboration) made it possible to determine, for the first time, the contributions of all isobar channels to the differential cross sections in question. The possibility of extracting the Q{sup 2} dependences of the electromagnetic form factors for the P{sub 11}(1440) and D{sub 13}(1520) resonances in a kinematical region that is the most sensitive to the contribution of the meson-baryon cloud to the structure of nucleon resonances is demonstrated.

  8. Isobar channels and nucleon resonances in pi+ pi- electroproduction on protons

    SciTech Connect

    Fedotov, Gleb; Burkert, Volker; Golovach, Evgeny; Elouadrhiri, Latifa; Isupov, Evgeny; Ishkhanov, Boris; Mokeev, Viktor; Shvedunov, Nikolay

    2008-07-01

    http://dx.doi.org/10.1134/S1063778808070272
    A comprehensive set of differential cross sections for the reaction y v p--> pi - pi + p at the square of the photon 4-momentum in the range 0.2 < Q 2 < 0.6 GeV2 and the invariant mass of final-state hadrons in the range 1.3 < W < 1.6 GeV was first obtained with the CLAS detector at the Thomas Jefferson Laboratory. An analysis of these data on the basis of the phenomenological model developed by physicists from the Institute of Nuclear Physics at Moscow State University (INP MSU) and Thomas Jefferson Laboratory (INP MSU-Hall B at Jefferson Lab Collaboration) made it possible to determine, for the first time, the contributions of all isobar channels to the differential cross sections in question. The possibility of extracting the Q 2 dependences of the electromagnetic form factors for the P 11(1440) and D 13(1520) resonances in a kinematical region that is the most sensitive to the contribution of the meson-baryon cloud to the str

  9. Ultra-high intra-spectrum mass accuracy enables unambiguous identification of fragment reporter ions in isobaric multiplexed quantitative proteomics.

    PubMed

    Pachl, Fiona; Fellenberg, Kurt; Wagner, Corinna; Kuster, Bernhard

    2012-05-01

    Isobaric tagging using reagents such as tandem mass tags (TMT) and isobaric tags for relative and absolute quantification (iTRAQ) have become popular tools for mass spectrometry based quantitative proteomics. Because the peptide quantification information is collected in tandem mass spectra, the accuracy and precision of this method largely depend on the resolution with which precursor ions can be selected for the fragmentation and the specificity of the generated reporter ion. The latter can constitute an issue if near isobaric ion signals are present in such spectra because they may distort quantification results. We propose a simple remedy for this problem by identifying reporter ions via the accurate mass differences within a single tandem mass spectrum instead of applying fixed mass error tolerances for all tandem mass spectra. Our results show that this leads to unambiguous reporter ion identification and complete removal of interfering signals. This mode of data processing is easily implemented in software and offers advantages for protein quantification based on few peptides. PMID:22589182

  10. Aircraft equilibrium spin characteristics

    NASA Technical Reports Server (NTRS)

    Adams, W. M., Jr.

    1980-01-01

    Program provides analytic solutions to nonlinear equations of motion describing spin conditions. Stability characteristics also are determined. Program can be used to study effects of aerodynamic and inertial parameters on spin and could be modified to compute equilibrium conditions for steady maneuvers. Program is written in FORTRAN IV for batch execution on CYBER 173.

  11. Equilibrium Chemical Engines

    E-print Network

    Tatsuo Shibata; Shin-ichi Sasa

    1997-10-30

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

  12. An Updated Equilibrium Machine

    ERIC Educational Resources Information Center

    Schultz, Emeric

    2008-01-01

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

  13. Relative Dispersion of isobaric RAFOS Floats off Central California: Comparative Analysis of Estimation Techniques

    NASA Astrophysics Data System (ADS)

    Margolina, T.; Collins, C. A.; Ivanov, L. M.; Hsieh, C.

    2006-12-01

    Dynamical regimes in the California Undercurrent and ocean interior off Central California are controlled by rich mesoscale activity, including eddies, filaments and turbulent jets. A unique dataset of 56 isobaric RAFOS floats was used to analyze relative dispersion in the region. The floats were launched in pairs and triads at 150- -600 m between 1993 and 2003 (http://www.oc.nps.navy.mil/npsRAFOS/). The launch design allowed us to identify about forty float pairs in several classes of initial separation distance. Taking into consideration the anisotropic nature of the California Undercurrent, alongshore and cross-shore separations were calculated for the identified pairs of float trajectories. We applied different techniques, both asymptotic and non-asymptotic, to estimate relative dispersion of the RAFOS floats. In addition to the probability distribution function of the mean square separation and its second- order moments, higher order moments were also considered to understand how much intermittency influence float dispersion. In addition to averaging distances at fixed times, two alternative approaches based on averaging times at fixed distance were tried, the finite size Lyapunov exponent and the parametrical exit time statistics. The latter was estimated both theoretically and using float sampling through the probability weighted moments. Statistical significance of the results as well as possible biases of the estimates due to horizontal and vertical shears were investigated. Different techniques give, in general, different dispersion regimes with power exponents varying between 0.5 and 2. Most differences occurred for the kurtosis and skewness at the initial stage for float pairs with small separation. The focus here was on finite sample size effects and an empirical criterion for evaluating the impact of sample size.

  14. An Updated Equilibrium Machine

    NASA Astrophysics Data System (ADS)

    Schultz, Emeric

    2008-08-01

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

  15. Equilibrium Electroconvective Instability

    NASA Astrophysics Data System (ADS)

    Rubinstein, I.; Zaltzman, B.

    2015-03-01

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

  16. Equilibrium electroconvective instability.

    PubMed

    Rubinstein, I; Zaltzman, B

    2015-03-20

    Since its prediction 15 years ago, hydrodynamic instability in concentration polarization at a charge-selective interface has been attributed to nonequilibrium electro-osmosis related to the extended space charge which develops at the limiting current. This attribution had a double basis. On the one hand, it has been recognized that neither equilibrium electro-osmosis nor bulk electroconvection can yield instability for a perfectly charge-selective solid. On the other hand, it has been shown that nonequilibrium electro-osmosis can. The first theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge selectivity for the sake of simplicity and so did the subsequent studies of various time-dependent and nonlinear features of electro-osmotic instability. In this Letter, we show that relaxing the assumption of perfect charge selectivity (tantamount to fixing the electrochemical potential of counterions in the solid) allows for the equilibrium electroconvective instability. In addition, we suggest a simple experimental test for determining the true, either equilibrium or nonequilibrium, origin of instability in concentration polarization. PMID:25839276

  17. Introduction to Carbonate Equilibrium

    NSDL National Science Digital Library

    michael stapleton

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

  18. ChemTeacher: Equilibrium Constant

    NSDL National Science Digital Library

    2011-01-01

    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.

  19. Phase coexistence in clusters: An ``experimental'' isobar and an elementary model

    E-print Network

    Berry, R. Stephen

    densities of states and thermodynamic properties, such as free energies and equilibrium ratios of coexisting based on highly simplified densities of states. The phase behavior of the alkali halide cluster is well interpret these results in terms of simple statistical­ thermodynamic models, slight variants of the Bixon

  20. Lecture Ch. 4a Equilibrium

    E-print Network

    Russell, Lynn

    equilibrium · Chemical equilibrium Reminders · Virtual Temperature: The temperature air would have1 Lecture Ch. 4a · Equilibrium · Phase changes · Enthalpy changes from phase changes ­ Latent-home point: For mixtures with more than one chemical component, there are more than 2 independent variables

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

    SciTech Connect

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

    1980-10-13

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

  2. Multiple equilibrium laboratory devices

    NASA Astrophysics Data System (ADS)

    Whitehead, J. A.

    2001-12-01

    Devices{* } will be demonstrated and videotapes played of a number of laboratory studies that exhibit multiple equilibrium. All devices have two competing effects driving the flow. In two of them, temperature and salinity oppose each other. In another, air and water compete. In a fourth, wave propagation is opposed by inertia. Connection with hypothesized ocean behavior will be made. {* } Whitehead, J. A. 2000 Stratified Convection with Multiple States. Ocean Modelling, 2, 109-121. Whitehead, J. A. W. Gregory Lawson and John Salzig. 2001 Multistate flow devices for geophysical fluid dynamics and climate. American Journal of Physics, 69 546-553. Whitehead, J. A. and P. G. Baines. 2000. Hydraulic Jump Location as a Multiple Equilibrium feature. 2000 Ocean Sciences Meeting, American Geophysical Union, San Antonio Texas, January 25, 2000. Abstract: EOS 80 #46 (Supplement), OS125. Whitehead, J. A. , M. L. E. Timmermans, W. Gregory Lawson, S. N. Bulgakov, A. M. Zatarian, J. F. A. Medina, and John Salzig, Laboratory studies of thermally and/or Salinity-driven flows with partial mixing: Part 1 Stommel transitions and multiple flow states. In preparation

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

    SciTech Connect

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

    1991-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    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.

  5. Collective-coupling analysis of spectra of mass-7 isobars: ^7He, ^7Li, ^7Be, ^7B

    E-print Network

    L. Canton; G. Pisent; K. Amos; S. Karataglidis; J. P. Svenne; D. van der Knijff

    2006-12-13

    A nucleon-nucleus interaction model has been applied to ascertain the underlying character of the negative-parity spectra of four isobars of mass seven, from neutron-- to proton--emitter driplines. With one single nuclear potential defined by a simple coupled-channel model, a multichannel algebraic scattering approach (MCAS) has been used to determine the bound and resonant spectra of the four nuclides, of which ^7He and ^7B are particle unstable. Incorporation of Pauli blocking in the model enables a description of all known spin-parity states of the mass-7 isobars. We have also obtained spectra of similar quality by using a large space no-core shell model. Additionally, we have studied ^7Li and ^7Be using a dicluster model. We have found a dicluster-model potential that can reproduce the lowest four states of the two nuclei, as well as the relevant low-energy elastic scattering cross sections. But, with this model, the rest of the energy spectra cannot be obtained.

  6. Weak Acid Equilibrium

    NSDL National Science Digital Library

    michael stapleton

    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.

  7. Grinding kinetics and equilibrium states

    NASA Technical Reports Server (NTRS)

    Opoczky, L.; Farnady, F.

    1984-01-01

    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.

  8. The Nash equilibrium: A perspective

    PubMed Central

    Holt, Charles A.; Roth, Alvin E.

    2004-01-01

    In 1950, John Nash contributed a remarkable one-page PNAS article that defined and characterized a notion of equilibrium for n- person games. This notion, now called the “Nash equilibrium,” has been widely applied and adapted in economics and other behavioral sciences. Indeed, game theory, with the Nash equilibrium as its centerpiece, is becoming the most prominent unifying theory of social science. In this perspective, we summarize the historical context and subsequent impact of Nash's contribution. PMID:15024100

  9. General Equilibrium Simulation for Microeconomics

    NSDL National Science Digital Library

    Betty Blecha

    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.

  10. The Greenhouse Effect Temperature Equilibrium

    E-print Network

    Walter, Frederick M.

    The Greenhouse Effect #12;Temperature Equilibrium The Earth is in equilibrium with the Sun temperature is about 14C, or 287K. The 40K difference is due to the greenhouse effect. Essentially all (Wein's Law). Our atmosphere is not completely transparent at these wavelengths, because the greenhouse

  11. Equilibrium analysis of volatility clustering

    Microsoft Academic Search

    Joel M. Vanden

    2005-01-01

    Volatility clustering is a pervasive feature of equity markets. This article studies volatility clustering in an equilibrium setting by generalizing the CRRA and CARA representative agent models of finance. In equilibrium, the market portfolio follows a volatility regime-switching process in which the volatility level is determined by the agent's local risk aversion. Using monthly data, the empirical tests reveal that

  12. Ion equilibrium in lichen surrounding.

    PubMed

    K?os, Andrzej; Rajfur, Ma?gorzata; Wac?awek, Maria; Wac?awek, Witold

    2005-04-01

    In laboratory conditions, the ionic equilibriums between a solution and a cation-active layer of epiphytic lichens Hypogymnia physodes immersed in the solution were examined. It was found that such equilibriums, due to exchange of mobile cations: H, Na, K, Ca, and Mg, are established in natural conditions between a lichen and atmospheric water. PMID:15833708

  13. Random Hamiltonian in thermal equilibrium

    E-print Network

    Dorje C. Brody; David C. P. Ellis; Darryl D. Holm

    2009-01-14

    A framework for the investigation of disordered quantum systems in thermal equilibrium is proposed. The approach is based on a dynamical model--which consists of a combination of a double-bracket gradient flow and a uniform Brownian fluctuation--that `equilibrates' the Hamiltonian into a canonical distribution. The resulting equilibrium state is used to calculate quenched and annealed averages of quantum observables.

  14. Radiative Equilibrium of the Mesosphere

    Microsoft Academic Search

    Conway Leovy

    1964-01-01

    Results of joint photochemical-radiative equilibrium calculations for the mesosphere and upper stratosphere are presented. The major assumptions were that only oxygen allotropes participate in the chemistry and that the radiative balance is between absorption of solar radiation by molecular oxygen and ozone and infrared emission by carbon dioxide and ozone. Equilibrium temperatures and ozone concentrations for winter and summer were

  15. CALCIUM EQUILIBRIUM IN MUSCLE

    PubMed Central

    Gilbert, Daniel L.; Fenn, Wallace O.

    1957-01-01

    1. A study of the calcium equilibrium in isolated frog muscle has been attempted. 2. When sartorius muscles were immersed in Ca45 Ringer's solution, the surface phase took up the Ca45 in about 1 minute; the extracellular water space and connective tissue in about 30 minutes; and the intracellular space in about 300 minutes. 3. The percentages of total calcium in the whole muscle immersed in Ringer's solution was as follows: 10 per cent in the surface phase; 12 per cent in the extracellular water space; 17 per cent in the dry connective tissue; 24 per cent in the intracellular space; and 37 per cent as non-exchangeable calcium. 4. The exchange constants of isolated frog sartorius muscle to calcium has been determined. The flux of intracellular calcium in the steady state was approximately 0.8 mM/(liter hr). 5. It appears that there is a calcium pump pushing calcium out of the cell against an electrochemical gradient of about 4 cal./mM of calcium. However, since the flux is low, the maximum energy required per hour to pump calcium out of the cell against this high gradient is only about 2 cal./kg. muscle or about 1 per cent of the resting energy. PMID:13398571

  16. Convective quasi-equilibrium

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  17. 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

    Joffrion, Lamar Lane

    1984-01-01

    to Bondi's recommendation (1964). Using Bondi's work s;/sf is 1. 13 for the IPA/APP mixture and 1. 06 for the n-heptane/APP mixture. In Figure 6, composition isotherms are shown for the IPA/APP mixture using interpolation and integration results...

  18. 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

    Joffrion, Lamar Lane

    1984-01-01

    ;-u) go uotqoung e se ' 'X 'uozgezquaouoo aseqd LzeuoTgegs aqua SuTqTzg uoTZezquaouoo aseqd ay~qorrr TeZog queqsuoo saumsse (e) uoTqenbz ge ze ze ae ( ? ~ ~- ? ) ~- ( ? ) rr~- = ( ? ) eV "xe ?' xe Ee sarrzS (y) uoTqenbX oiuT (Z) uoTqenbX pue qgnsaz...Tzqom te'Zol = N ssem aseqd Azeuozgeqs peyote = asaqg ze 0 = ? [ "?q?Z (~v)e N + ?([ (z-. x) + ): ( ? ) ] rr se uaQQTJN Agquazuarruoo azom aq r&em (9) uozsen6g 'guauodmoo izaut amos qsvrr magsAs aqua yo uoS&eqzn&sad Zq pautmsasap aq fiem L...

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

    PubMed Central

    Su, Dian; Gaffrey, Matthew J.; Guo, Jia; Hatchell, Kayla E.; Chu, Rosalie K.; Clauss, Therese R. W.; Aldrich, Joshua T.; Wu, Si; Purvine, Sam; Camp, David G.; Smith, Richard D.; Thrall, Brian D.; Qian, Wei-Jun

    2014-01-01

    S-glutathionylation (SSG) is an important regulatory posttranslational modification on protein cysteine (Cys) thiols, 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 covalent capture of reduced thiols 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 initially 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, thus providing a database of proteins and Cys-sites susceptible to this modification under oxidative stress. Functional analysis revealed that the most significantly enriched molecular function categories for proteins sensitive to SSG modifications were free radical scavenging and cell death/survival. Overall the results demonstrate that our approach is effective for site-specific identification and quantification of SSG-modified proteins. The analytical strategy also provides a unique approach to determining the major pathways and cellular processes most susceptible to S-glutathionylation under stress conditions. PMID:24333276

  20. Intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine for infraumbilical surgery under subarachnoid block: A prospective study

    PubMed Central

    Gupta, Kumkum; Singh, Surjeet; Sharma, Deepak; Gupta, Prashant K.; Krishan, Atul; Pandey, M. N.

    2014-01-01

    Background: Subarachnoid blockade can be used in all surgical procedures carried out on the infraumbilical region. This study was aimed to evaluate the clinical efficacy and safety of intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine on onset, duration, intensity, and recovery time of sensory and motor blockade of subarachnoid block for infra umbilical surgery. Methods: One hundred sixty adult consented patients of either gender with American Society of Anesthesiologist ASA I and II scheduled for infraumbilical surgery were randomized into two groups of 80 patients each to receive either intrathecal study solution of 4 mL of 0.75% ropivacaine with 0.4 mL of 0.9% sodium chloride (Group I-Ropivacaine Control Group RC) or fentanyl (20 ?g) (Group II-Ropivacaine with Fentanyl RF). The end points were hemodynamic variability, onset of analgesia at T 10, maximum sensory analgesic level, time to complete motor blockade, duration of sensory and motor blockade and adequacy of surgical anesthesia. The post-spinal nausea and vomiting, shivering, pruritus, respiratory depression or any other side-effects were also assessed. At the end of study, data were systematically complied and analyzed for statistically significance. Result: The intrathecal fentanyl has accelerated the onset time to achieve sensory blockade to T10 dermatome and motor blockade. Small dose of intrathecal fentanyl with ropivacaine has prolonged the duration of analgesia in the early post-operative period when compared with intrathecal ropivacaine alone. The intraoperative hemodynamic variability showed no statistically significant differences between groups. Conclusion: Intrathecal fentanyl as an adjuvant to 0.75% isobaric ropivacaine demonstrated better clinical profile as compared to ropivacaine alone. PMID:24665242

  1. Relative quantification of proteins in human cerebrospinal fluids by MS/MS using 6-plex isobaric tags.

    PubMed

    Dayon, Loïc; Hainard, Alexandre; Licker, Virginie; Turck, Natacha; Kuhn, Karsten; Hochstrasser, Denis F; Burkhard, Pierre R; Sanchez, Jean-Charles

    2008-04-15

    A new 6-plex isobaric mass tagging technology is presented, and proof of principle studies are carried out using standard protein mixtures and human cerebrospinal fluid (CSF) samples. The Tandem Mass Tags (TMT) comprise a set of structurally identical tags which label peptides on free amino-terminus and epsilon-amino functions of lysine residues. During MS/MS fragmentation, quantification information is obtained through the losses of the reporter ions. After evaluation of the relative quantification with the 6-plex version of the TMT on a model protein mixture at various concentrations, the quantification of proteins in CSF samples was performed using shotgun methods. Human postmortem (PM) CSF was taken as a model of massive brain injury and comparison was carried out with antemortem (AM) CSF. After immunoaffinity depletion, triplicates of AM and PM CSF pooled samples were reduced, alkylated, digested by trypsin, and labeled, respectively, with the six isobaric variants of the TMT (with reporter ions from m/z = 126.1 to 131.1 Th). The samples were pooled and fractionated by SCX chromatography. After RP-LC separation, peptides were identified and quantified by MS/MS analysis with MALDI TOF/TOF and ESI-Q-TOF. The concentration of 78 identified proteins was shown to be clearly increased in PM CSF samples compared to AM. Some of these proteins, like GFAP, protein S100B, and PARK7, have been previously described as brain damage biomarkers, supporting the PM CSF as a valid model of brain insult. ELISA for these proteins confirmed their elevated concentration in PM CSF. This work demonstrates the validity and robustness of the tandem mass tag (TMT) approach for quantitative MS-based proteomics. PMID:18312001

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

    SciTech Connect

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

    2014-02-11

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

  3. Proteomic identification and quantification of S-glutathionylation in mouse macrophages using resin-assisted enrichment and isobaric labeling.

    PubMed

    Su, Dian; Gaffrey, Matthew J; Guo, Jia; Hatchell, Kayla E; Chu, Rosalie K; Clauss, Therese R W; Aldrich, Joshua T; Wu, Si; Purvine, Sam; Camp, David G; Smith, Richard D; Thrall, Brian D; Qian, Wei-Jun

    2014-02-01

    S-Glutathionylation (SSG) is an important regulatory posttranslational modification on protein cysteine (Cys) thiols, 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 covalent capture of reduced thiols 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 initially 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, thus providing a database of proteins and Cys sites susceptible to this modification under oxidative stress. Functional analysis revealed that the most significantly enriched molecular function categories for proteins sensitive to SSG modifications were free radical scavenging and cell death/survival. Overall the results demonstrate that our approach is effective for site-specific identification and quantification of SSG-modified proteins. The analytical strategy also provides a unique approach to determining the major pathways and cellular processes most susceptible to S-glutathionylation under stress conditions. PMID:24333276

  4. Equilibrium relationships for non-equilibrium chemical dependencies

    E-print Network

    Gregory S. Yablonsky; Denis Constales; Guy B. Marin

    2010-07-27

    In contrast to common opinion, it is shown that equilibrium constants determine the time-dependent behavior of particular ratios of concentrations for any system of reversible first-order reactions. Indeed, some special ratios actually coincide with the equilibrium constant at any moment in time. This is established for batch reactors, and similar relations hold for steady-state plug-flow reactors, replacing astronomic time by residence time. Such relationships can be termed time invariants of chemical kinetics.

  5. Helical axis stellarator equilibrium model

    SciTech Connect

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

    1985-02-01

    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.

  6. Tuning, ergodicity, equilibrium, and cosmology

    NASA Astrophysics Data System (ADS)

    Albrecht, Andreas

    2015-05-01

    I explore the possibility that the cosmos is fundamentally an equilibrium system and review the attractive features of such theories. Equilibrium cosmologies are commonly thought to fail due to the "Boltzmann brain" problem. I show that it is possible to evade the Boltzmann brain problem if there is a suitable coarse-grained relationship between the fundamental degrees of freedom and the cosmological observables. I make my main points with simple toy models and then review the de Sitter equilibrium model as an illustration.

  7. Understanding thermal equilibrium through activities

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    Thermal equilibrium is a basic concept in thermodynamics. In India, this concept is generally introduced at the first year of undergraduate education in physics and chemistry. In our earlier studies (Pathare and Pradhan 2011 Proc. episteme-4 Int. Conf. to Review Research on Science Technology and Mathematics Education pp 169–72) we found that students in India have a rather unsatisfactory understanding of thermal equilibrium. We have designed and developed a module of five activities, which are presented in succession to the students. These activities address the students’ alternative conceptions that underlie their lack of understanding of thermal equilibrium and aim at enhancing their understanding of the concept.

  8. Equilibrium Constants You Can Smell.

    ERIC Educational Resources Information Center

    Anderson, Michael; Buckley, Amy

    1996-01-01

    Presents a simple experiment involving the sense of smell that students can accomplish during a lecture. Illustrates the important concepts of equilibrium along with the acid/base properties of various ions. (JRH)

  9. Equilibrium ignition for ICF capsules

    SciTech Connect

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

    1993-12-31

    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.

  10. Equilibrium Electro-osmotic Instability

    E-print Network

    Rubinstein, Isaak

    2014-01-01

    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...

  11. NUMERICAL VERIFICATION OF EQUILIBRIUM CHEMISTRY

    SciTech Connect

    Piro, Markus [Royal Military College of Canada; Lewis, Brent [Royal Military College of Canada; Thompson, Dr. William T. [Royal Military College of Canada; Simunovic, Srdjan [ORNL; Besmann, Theodore M [ORNL

    2010-01-01

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

  12. Edge equilibrium code for tokamaks

    SciTech Connect

    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

    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.

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

    PubMed

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

    2011-12-21

    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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  15. Fundamental functions in equilibrium thermodynamics

    NASA Astrophysics Data System (ADS)

    ter Horst, H. J.

    1987-06-01

    In the standard presentations of the principles of Gibbsian equilibrium thermodynamics one can find several gaps in the logic. For a subject that is as widely used as equilibrium thermodynamics, it is of interest to clear up such questions of mathematical rigor. In this paper it is shown that using convex analysis one can give a mathematically rigorous treatment of several basic aspects of equilibrium thermodynamics. On the basis of a fundamental convexity property implied by the second law, the following topics are discussed: thermodynamic stability, transformed fundamental functions (such as the Gibbs free energy), and the existence and uniqueness of possible final equilibrium states of closed composite thermodynamic systems. It is shown that a standard mathematical characterization of thermodynamic stability (involving a positive definiteness property) is sufficient but in fact not necessary for the physically superior convexity characterization of thermodynamic stability. Furthermore, it is found that functions such as the Gibbs free energy can be rigorously and globally defined using convex conjugation instead of Legendre transformation. Another result desribed in this paper is that equilibrium thermodynamics cannot always uniquely predict possible final equilibrium states of closed composite thermodynamic systems.

  16. Week12: Chapter 12 Static Equilibrium

    E-print Network

    1 Week12: Chapter 12 Static Equilibrium and Elasticity Static Equilibrium Equilibrium implies the object is at rest (static) or its center of mass moves with a constant velocity (dynamic) Static equilibrium is a common situation in engineering Principles involved are of particular interest to civil

  17. Chemical Principles Revisited: Using the Equilibrium Concept.

    ERIC Educational Resources Information Center

    Mickey, Charles D., Ed.

    1981-01-01

    Discusses the concept of equilibrium in chemical systems, particularly in relation to predicting the position of equilibrium, predicting spontaneity of a reaction, quantitative applications of the equilibrium constant, heterogeneous equilibrium, determination of the solubility product constant, common-ion effect, and dissolution of precipitates.…

  18. Tuning universality far from equilibrium

    E-print Network

    Markus Karl; Boris Nowak; Thomas Gasenzer

    2013-02-05

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

  19. Detecting temperature fluctuations at equilibrium.

    PubMed

    Dixit, Purushottam D

    2015-05-01

    The Gibbs and the Boltzmann definition of temperature agree only in the macroscopic limit. The ambiguity in identifying the equilibrium temperature of a finite-sized 'small' system exchanging energy with a bath is usually understood as a limitation of conventional statistical mechanics. We interpret this ambiguity as resulting from a stochastically fluctuating temperature coupled with the phase space variables giving rise to a broad temperature distribution. With this ansatz, we develop the equilibrium statistics and dynamics of small systems. Numerical evidence using an analytically tractable model shows that the effects of temperature fluctuations can be detected in the equilibrium and dynamical properties of the phase space of the small system. Our theory generalizes statistical mechanics to small systems relevant in biophysics and nanotechnology. PMID:25912565

  20. Tuning universality far from equilibrium

    NASA Astrophysics Data System (ADS)

    Karl, Markus; Nowak, Boris; Gasenzer, Thomas

    2013-08-01

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

  1. Detecting temperature fluctuations at equilibrium

    E-print Network

    Dixit, Purushottam D

    2015-01-01

    Gibbs and Boltzmann definitions of temperature agree only in the macroscopic limit. The ambiguity in identifying the equilibrium temperature of a finite sized `small' system exchanging energy with a bath is usually understood as a limitation of conventional statistical mechanics. We interpret this ambiguity as resulting from a stochastically fluctuating temperature coupled with the phase space variables giving rise to a broad temperature distribution. With this ansatz, we develop the equilibrium statistics and dynamics of small systems. Numerical evidence using an analytically tractable model shows that the effects of temperature fluctuations can be detected in equilibrium and dynamical properties of the phase space of the small system. Our theory generalizes statistical mechanics to small systems relevant to biophysics and nanotechnology.

  2. The effect of the pairing interaction on the energies of isobar analogue resonances in 112 124Sb and isospin admixture in 100 124Sn isotopes

    Microsoft Academic Search

    Tahsin Babacan; Djavad Salamov; Atalay Kücükbursa; Halil Babacan; Ismail Maras; Hasan A. Aygör; Arslan Ünal

    2004-01-01

    In the present study, the effect of the pairing interaction and the isovector correlation between nucleons on the properties of the isobar analogue resonances (IAR) in 112-124Sb isotopes and the isospin admixture in 100-124Sn isotopes is investigated within the framework of the proton-neutron quasi-particle random phase approximation (pnQRPA). The form of the interaction strength parameter is related to the shell-model

  3. Angular distributions for the double isobaric analog and a T< state at high excitation in pion double charge exchange on 93Nb

    Microsoft Academic Search

    C. Fred Moore; K. Johnson; G. P. Kahrimanis; James McDonald; M. Snell; H. J. Ward; Sung Hoon Yoo; C. L. Morris; S. Mordechai; M. Burlein; N. Claytor; H. T. Fortune; R. Ivie; G. B. Liu; J. M. O'donnell; D. Smith; N. Auerbach; D. Robson

    1991-01-01

    The double isobaric analog state ||IAS??IAS> and a new resonance below the ||IAS?IAS> have been observed in pion-induced double-charge-exchange reactions on 93Nb. Angular distributions have been measured for both transitions. The cross section observed in the T< resonance is 21% of that for the ||IAS?IAS> in 93Tc. We mention various possibilities for the nature of the observed resonance but have

  4. Proteomic Quantification and Site-Mapping of S-Nitrosylated Proteins Using Isobaric iodoTMT Reagents

    PubMed Central

    2015-01-01

    S-Nitrosylation is a redox-based protein post-translational modification in response to nitric oxide signaling and is involved in a wide range of biological processes. Detection and quantification of protein S-nitrosylation have been challenging tasks due to instability and low abundance of the modification. Many studies have used mass spectrometry (MS)-based methods with different thiol-reactive reagents to label and identify proteins with S-nitrosylated cysteine (SNO-Cys). In this study, we developed a novel iodoTMT switch assay (ISA) using an isobaric set of thiol-reactive iodoTMTsixplex reagents to specifically detect and quantify protein S-nitrosylation. Irreversible labeling of SNO-Cys with the iodoTMTsixplex reagents enables immune-affinity detection of S-nitrosylated proteins, enrichment of iodoTMT-labeled peptides by anti-TMT resin, and importantly, unambiguous modification site-mapping and multiplex quantification by liquid chromatography–tandem MS. Additionally, we significantly improved anti-TMT peptide enrichment efficiency by competitive elution. Using ISA, we identified a set of SNO-Cys sites responding to lipopolysaccharide (LPS) stimulation in murine BV-2 microglial cells and revealed effects of S-allyl cysteine from garlic on LPS-induced protein S-nitrosylation in antioxidative signaling and mitochondrial metabolic pathways. ISA proved to be an effective proteomic approach for quantitative analysis of S-nitrosylation in complex samples and will facilitate the elucidation of molecular mechanisms of nitrosative stress in disease. PMID:24926564

  5. Quantitative proteomics analysis of maternal plasma in Down syndrome pregnancies using isobaric tagging reagent (iTRAQ).

    PubMed

    Kolla, Varaprasad; Jenö, Paul; Moes, Suzette; Tercanli, Sevgi; Lapaire, Olav; Choolani, Mahesh; Hahn, Sinuhe

    2010-01-01

    Currently no specific biomarkers exist for the screening of pregnancies at risk for Down syndrome (DS). Since a quantitative proteomic approach with isobaric labelling (iTRAQ) has recently been suggested to be highly suitable for the discovery of novel plasma biomarkers, we have now used this method to examine for potential quantitative changes in the plasma proteome of the pregnancies bearing DS fetuses in comparison to normal healthy babies. In our study, we used plasma from six women with DS pregnancies and six with uncomplicated pregnancies care were taken to match cases and controls for gestational and maternal age, as these could be a confounder. In our quantitative proteomics analysis we were able to detect 178 proteins using iTRAQ labelling in conjunction with 4800 MALDI TOF/TOF. Amongst these we observed changes in betaHCG, a known screening marker for DS, indicating that our assay was functional. We found a number of elevated proteins Ig lambda chain C region, serum amyloid P-component, amyloid beta A4, and under expressed proteins like gamma-actin and titin in DS pregnancies. These proteins are also found in the sera of patients with Alzheimer disease, which share similar pathologies of DS. Our study therefore indicates that the iTRAQ labelling approach may be indeed useful for the detection of novel biomarkers. PMID:19902006

  6. Quantitative Proteomics Analysis of Maternal Plasma in Down Syndrome Pregnancies Using Isobaric Tagging Reagent (iTRAQ)

    PubMed Central

    Kolla, Varaprasad; Jenö, Paul; Moes, Suzette; Tercanli, Sevgi; Lapaire, Olav; Choolani, Mahesh; Hahn, Sinuhe

    2010-01-01

    Currently no specific biomarkers exist for the screening of pregnancies at risk for down syndrome (DS). Since a quantitative proteomic approach with isobaric labelling (iTRAQ) has recently been suggested to be highly suitable for the discovery of novel plasma biomarkers, we have now used this method to examine for potential quantitative changes in the plasma proteome of the pregnancies bearing DS fetuses in comparison to normal healthy babies. In our study, we used plasma from six women with DS pregnancies and six with uncomplicated pregnancies care were taken to match cases and controls for gestational and maternal age, as these could be a confounder. In our quantitative proteomics analysis we were able to detect 178 proteins using iTRAQ labelling in conjunction with 4800 MALDI TOF/TOF. Amongst these we observed changes in ?HCG, a known screening marker for DS, indicating that our assay was functional. We found a number of elevated proteins Ig lambda chain C region, serum amyloid P-component, amyloid beta A4, and under expressed proteins like gamma-actin and titin in DS pregnancies. These proteins are also found in the sera of patients with Alzheimer disease, which share similar pathologies of DS. Our study therefore indicates that the iTRAQ labelling approach may be indeed useful for the detection of novel biomarkers. PMID:19902006

  7. Adiabatic evolution of plasma equilibrium

    PubMed Central

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

    1975-01-01

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

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

    DOEpatents

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

    1980-01-01

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

  9. Secondary Ion Mass Spectrometry of Vapor-Liquid-Solid Grown,

    E-print Network

    Atwater, Harry

    ) tomography has been used to probe the concentration of Au in 100 nm diameter Si wires grown by chemical vapor) scanning transmission electron microscopy (STEM) has been used to spatially localize single Au atoms within 15 nm diameter Si wires grown by CVD at 450 °C,14 as well as 30 nm diameter Si wires grown

  10. Microwave Remote Sensing Techniques for Vapor, Liquid and Ice Parameters

    Microsoft Academic Search

    Li. Li

    1995-01-01

    The objective of this dissertation is to develop a comprehensive physical inverse model for microwave remote sensing of atmospheric components. This novel approach provides a rigorous basis for understanding and extracting the physical information content of radiometer and\\/or radar measurements of the atmospheric media. To this end, a comprehensive parametric radiative transfer model (forward model) is developed first and then

  11. Direct Observation of Vapor-Liquid-Solid Nanowire Growth

    E-print Network

    Yang, Peidong

    , crystal nucleation, and axial growth. On the basis of this mechanism study, selective growth of Si, 12, 605-607. (11) Tang, C. C.; Fan, S. S.; Dang, H. Y.; Li, P.; Liu, Y. M. Appl. Phys. Lett. 2000, 77

  12. Pattern formation outside of equilibrium

    Microsoft Academic Search

    M. C. Cross; P. C. Hohenberg

    1993-01-01

    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.

  13. Equilibrium problems for Raney densities

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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 < r ? p, and form the moments of a probability density function. For certain (p, r) the latter has the interpretation as the density of squared singular values for certain random matrix ensembles, and in this context equilibrium problems characterising the Raney densities for (p, r) = (? + 1, 1) and (?/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 ? > 0 and similarly use both methods to identify the equilibrium problem for (p, r) = (?/q + 1, 1/q), ? > 0 and q \\in Z+ . The Wiener–Hopf method is used to extend the latter to parameters (p, r) = (?/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.

  14. LABORATORY I FORCES AND EQUILIBRIUM

    E-print Network

    Minnesota, University of

    LABORATORY I FORCES AND EQUILIBRIUM Lab I -1 In biological systems, most objects of interest system. OBJECTIVES: After successfully completing this laboratory, you should be able to: · Determine and 6), and chapter 15 (section 4). It is likely that you will be doing some of these laboratory

  15. Equilibrium Statistical Mechanics Giovanni Gallavotti

    E-print Network

    Roma "La Sapienza", Università di

    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

  16. Equilibrium Statistical Mechanics Giovanni Gallavotti

    E-print Network

    Roma "La Sapienza", Università di

    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

  17. High spatial resolution equilibrium reconstruction

    NASA Astrophysics Data System (ADS)

    Ren, Q.; Chu, M. S.; Lao, L. L.; Srinivasan, R.

    2011-09-01

    The extension of the EFIT equilibrium reconstruction code to fine spatial-grid resolutions is discussed. The residue in the force-balance relation of the Grad-Shafranov (G-S) equation and the convergence property of these fine spatial-grid EFIT equilibria are studied in detail. The results suggest that fine spatial-grid equilibria generally better satisfy the force-balance constraint described by the G-S equation. Finer spatial-grid equilibria have typically smaller average error in satisfying the force-balance equation than coarse-grid equilibria and those extrapolated from coarse-grid results. Analysis of the equilibrium iteration algorithm employed in EFIT reveals that the iteration process is related to the spatial feedback stabilization of the plasma with flux control at various specified locations. Thus, for a converged equilibrium, axisymmetric stability is generally expected with feedback. The iteration error decreases self-similarly in the final stage of the iteration process and is related to the least stable axisymmetric mode in the feedback-stabilized equilibrium.

  18. Quantifying mixing using equilibrium reactions

    SciTech Connect

    Wheat, Philip M. [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, Arizona 85287-6106 (United States); Posner, Jonathan D. [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, Arizona 85287-6106 (United States); Department of Chemical Engineering, Arizona State University, Tempe, Arizona 85287-6106 (United States)

    2009-03-15

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

  19. Quantitative analysis of human cerebrospinal fluid proteins using a combination of cysteine tagging and amine-reactive isobaric labeling.

    PubMed

    Giron, Priscille; Dayon, Loïc; Turck, Natacha; Hoogland, Christine; Sanchez, Jean-Charles

    2011-01-01

    Highly complex and dynamic protein mixtures are hardly comprehensively resolved by direct shotgun proteomic analysis. As many proteins of biological interest are of low abundance, numerous analytical methodologies have been developed to reduce sample complexity and go deeper into proteomes. The present work describes an analytical strategy to perform cysteinyl-peptide subset enrichment and relative quantification through successive cysteine and amine-isobaric tagging. A cysteine-reactive covalent capture tag (C³T) allowed derivatization of cysteines and specific isolation on a covalent capture (CC) resin. The 6-plex amine-reactive tandem mass tags (TMT) served for relative quantification of the targeted peptides. The strategy was first evaluated on a model protein mixture with increasing concentrations to assess the specificity of the enrichment and the quantitative performances of the workflow. It was then applied to human cerebrospinal fluid (CSF) from post-mortem and ante-mortem samples. These studies confirmed the specificity of the C³T and the CC technique to cysteine-containing peptides. The model protein mixture analysis showed high precision and accuracy of the quantification with coefficients of variation and mean absolute errors of less than 10% on average. The CSF experiments demonstrated the potential of the strategy to study complex biological samples and identify differential brain-related proteins. In addition, the quantification data were highly correlated with a classical TMT experiment (i.e., without C³T cysteine-tagging and enrichment steps). Altogether, these results legitimate the use of this quantitative C³T strategy to enrich and relatively quantify cysteine-containing peptides in complex mixtures. PMID:20973565

  20. X-ray continuum as a measure of pressure and fuel-shell mix in compressed isobaric hydrogen implosion cores

    NASA Astrophysics Data System (ADS)

    Epstein, R.; Goncharov, V. N.; Marshall, F. J.; Betti, R.; Nora, R.; Christopherson, A. R.; Golovkin, I. E.; MacFarlane, J. J.

    2015-02-01

    Pressure, by definition, characterizes the conditions within an isobaric implosion core at peak compression [Gus'kov et al., Nucl. Fusion 16, 957 (1976); Betti et al., Phys. Plasmas 8, 5257 (2001)] and is a key parameter in quantifying its near-ignition performance [Lawson, Proc. Phys. Soc. London, B 70, 6 (1957); Betti et al., Phys. Plasmas 17, 058102 (2010); Goncharov et al., Phys. Plasmas 21, 056315 (2014); and Glenzer et al., Phys. Plasmas 19, 056318 (2012)]. At high spectral energy, where the x-ray emission from an imploded hydrogen core is optically thin, the emissivity profile can be inferred from the spatially resolved core emission. This emissivity, which can be modeled accurately under hot-core conditions, is dependent almost entirely on the pressure when measured within a restricted spectral range matched to the temperature range anticipated for the emitting volume. In this way, the hot core pressure at the time of peak emission can be inferred from the measured free-free emissivity profile. The pressure and temperature dependences of the x-ray emissivity and the neutron-production rate explain a simple scaling of the total filtered x-ray emission as a constant power of the total neutron yield for implosions of targets of similar design over a broad range of shell implosion isentropes. This scaling behavior has been seen in implosion simulations and is confirmed by measurements of high-isentrope implosions [Sangster et al., Phys. Plasmas 20, 056317 (2013)] on the OMEGA laser system [Boehly et al., Opt. Commun. 133, 495 (1997)]. Attributing the excess emission from less-stable, low-isentrope implosions, above the level expected from this neutron-yield scaling, to the higher emissivity of shell carbon mixed into the implosion's central hot spot, the hot-spot "fuel-shell" mix mass can be inferred.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  2. Thermal Equilibrium Calorimeters -- An Introduction

    E-print Network

    McCammon, D

    2005-01-01

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

  3. Thermal Equilibrium Calorimeters -- An Introduction

    E-print Network

    Dan McCammon

    2005-03-07

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

  4. Phonon Mapping in Flowing Equilibrium

    NASA Astrophysics Data System (ADS)

    Ruff, J. P. C.

    2015-03-01

    When a material conducts heat, a modification of the phonon population occurs. The equilibrium Bose-Einstein distribution is perturbed towards flowing-equilibrium, for which the distribution function is not analytically known. Here I argue that the altered phonon population can be efficiently mapped over broad regions of reciprocal space, via diffuse x-ray scattering or time-of-flight neutron scattering, while a thermal gradient is applied across a single crystal sample. When compared to traditional transport measurements, this technique offers a superior, information-rich new perspective on lattice thermal conductivity, wherein the band and momentum dependences of the phonon thermal current are directly resolved. The proposed method is benchmarked using x-ray thermal diffuse scattering measurements of single crystal diamond under transport conditions. CHESS is supported by the NSF & NIH/NIGMS via NSF Award DMR-1332208.

  5. Equilibrium cluster formation and gelation

    E-print Network

    Rodrigo Sanchez; Paul Bartlett

    2005-06-22

    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.

  6. The radiation equilibrium is classical

    Microsoft Academic Search

    V. Guruprasad

    2006-01-01

    By definition, standing wave modes cannot interact among themselves, plus non-zero temperature means real walls must vibrate. Modal interaction by Doppler shifts at the walls is thus an unavoidable premise in cavity equilibrium, but it also suffices to yield Planck's law classically, as follows. lambda\\/2-intervals of the modes are immutable energy-bearing entities under these thermalizing interactions, like molecules in the

  7. Chemical Equilibrium and Isotope Temperatures

    E-print Network

    J. Pochodzalla; W. Trautmann

    2000-09-20

    The measurement and interpretation of isotopic yield ratios in heavy ion reactions at intermediate and high energies are discussed and the usefulness of these observables for establishing equilibrium properties and for determining thermodynamic parameters is illustrated. The examples are mainly taken from work performed with lighter projectiles at intermediate and high energies and from studies of spectator reactions at relativistic energies. As an application, the caloric curve of nuclei, as derived for Au on Au collisions, is introduced and discussed.

  8. Punctuated equilibrium comes of age

    NASA Astrophysics Data System (ADS)

    Gould, Stephan Jay; Eldredge, Niles

    1993-11-01

    The intense controversies that surrounded the youth of punctuated equilibrium have helped it mature to a useful extension of evolutionary theory. As a complement to phyletic gradualism, its most important implications remain the recognition of stasis as a meaningful and predominant pattern within the history of species, and in the recasting of macroevolution as the differential success of certain species (and their descendants) within clades.

  9. Non-equilibrium Thermodynamics of Glassy Systems

    NASA Astrophysics Data System (ADS)

    Aung, Pyie; Puru, Gujrati

    2011-04-01

    When a linear amorphous polymer is in the glassy state, equilibrium thermodynamics theory is no longer consistent, for, a glass cannot be described by equilibrium statistical mechanics. Therefore, a non-equilibrium thermodynamics approach has been developed, which we intend to apply to glasses. The approach starts from the most general law of nature, the second law of thermodynamics, and shows correction terms that are missing in the conventional non-equilibrium thermodynamics of de Donder and Prigogine. We have applied this new approach and have discovered the generalization of (equilibrium) Maxwell's relations to non-equilibrium states. The generalization replaces simple partial derivatives by Jacobians' Matrices. The non-equilibrium Maxwell's relations lead to one the most paradoxical equations, the Prigogine-Defay ratio. The goal of this research is to understand non-equilibrium states with an emphasis on glasses and to solve the Prigogine-Defay ratio paradox with deeper definitions.

  10. Consumer Equilibrium -- From Equimarginal to Indifference.

    ERIC Educational Resources Information Center

    Reynolds, Dave

    1988-01-01

    Presents a classroom exercise which illustrates consumer equilibrium, the equimarginal principle, indifference curves, and income and substitution effects. States that students gain a better consumer equilibrium by linking together these elements of economic analysis. (GEA)

  11. Reflective equilibrium and the 'moral conservatism' objection

    E-print Network

    Chandler, James Robert

    2002-01-01

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

  12. Torque equilibrium attitude control for Skylab reentry

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  13. Equilibrium 2 H fractionations in organic molecules

    E-print Network

    Sessions, Alex L.

    .e., the equilibrium isotopic fractionation factor (aeq). To date, relevant data have been lacking for molecules larger to calculate the temperature-dependent equilibrium isotopic fractionation factors for a range of linearEquilibrium 2 H/1 H fractionations in organic molecules: I. Experimental calibration of ab initio

  14. Two Suggestions for Improving Chemical Equilibrium Instruction

    E-print Network

    Yaron, David

    Two Suggestions for Improving Chemical Equilibrium Instruction Journal: Journal of Chemical to the Journal of Chemical Education #12;ed-20XX-XXXXXX Two Suggestions for Improving Chemical Equilibrium Chemical Equilibrium Instruction David Yaron*1, Jodi L. Davenport2, James Greeno3, Michael Karabinos1

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

    PubMed

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

    2014-12-01

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

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

    Microsoft Academic Search

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

    An amine specific peptide derivatization strategy involving the use of novel isobaric stable isotope encoded ‘fixed charge’\\u000a sulfonium ion reagents, coupled with an analysis strategy employing capillary HPLC, ESI-MS, and automated data dependent ion\\u000a trap CID-MS\\/MS, -MS3, and\\/or ETD-MS\\/MS, has been developed for the improved quantitative analysis of protein phosphorylation, and for identification\\u000a and characterization of their site(s) of modification.

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

    E-print Network

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

    2007-07-21

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

  18. Angular distributions for the double isobaric analog and a T sub lt state at high excitation in pion double charge exchange on sup 93 Nb

    Microsoft Academic Search

    C. F. Moore; K. Johnson; G. P. Kahrimanis; J. McDonald; M. Snell; H. J. Ward; S. H. Yoo; C. L. Morris; S. Mordechai; M. Burlein; N. Claytor; H. T. Fortune; R. Ivie; G. B. Liu; J. M. ODonnell; D. Smith; N. Auerbach; D. Robson

    1991-01-01

    The double isobaric analog state {vert bar}IAS{direct product}{direct product}IAS{r angle} and a new resonance below the {vert bar}IAS{direct product}IAS{r angle} have been observed in pion-induced double-charge-exchange reactions on ⁹³Nb. Angular distributions have been measured for both transitions. The cross section observed in the {ital T}{sub >} resonance is 21% of that for the {vert bar}IAS{direct product}IAS{r angle} in ⁹³Tc. We

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    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.

  20. Rapid separation of isobar nuclides of alkali and alkaline earth elements by use of a surface ion source

    NASA Astrophysics Data System (ADS)

    Schmick, H.-D.; Wassmuth, H.-W.

    1980-02-01

    Using a magnetic mass spectrometer we studied the applicability of (positive) surface ionization to rapid separation of isobar nuclides, especially of alkali and alkaline earth elements. For this purpose the nuclides to be separated were evaporated onto a tungsten ribbon, which was subsequently flashed by resistive heating to about 2500 K in a typical time of 100 ms. During the flash the adsorbed species desorb partly ionized and pass the mass spectrometer, which is tuned to the desired mass number. The recorded signal shows two peaks arising at different times after having started the flash according to the mean residence times of the respective elements. The peaks are completely separated in time scale (and thus in the corresponding temperature scale, too) if the difference of the desorption energies is sufficient. This is the case with Rb (2.09 eV) and Sr (3.7 eV), which reach their maxima of desorption at about 1100 K and 1800 K, respectively depending to some extent on the heating rate. The different peak heights in the desorption spectrum are primarily determined by the ionization energies of the elements and represent ionic yields of 95% for Rb (4.17 eV) and 10 -3 for Sr (5.69 eV). The value for Sr could be increased to about 20% when the tungsten ribbon was covered with oxygen up to nearly one monolayer during the separation cycle, a procedure which additionally improved the separation efficiency. We also did some computer calculations based on measurements of the desorption parameters of the alkali and alkaline earth elements on a tungsten surface, which reproduced the experimental results of Rb/Sr quite well. Therefore we extended these calculations to K/Ca and Cs/Ba with the following results: These elements are completely separable as well, and the yields for K and Cs of the same order of magnitude as that for Rb (70% for K, 99% for Cs), while those for Ca and Ba are 7 × 10 -4 and 3%, respectively. The latter values might be raised to about one to some ten percent by an adequate oxygen coverage of the ionizing surface.

  1. Vadose zone isobaric well

    DOEpatents

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

    2001-01-01

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

  2. Structural properties of methanol-water binary mixtures within the quantum cluster equilibrium model.

    PubMed

    Matisz, G; Kelterer, A-M; Fabian, W M F; Kunsági-Máté, S

    2015-04-01

    Density functional theory (B3LYP-D3, M06-2X) has been used to calculate the structures, interaction energies and vibrational frequencies of a set of 93 methanol-water clusters of different type (cubic, ring, spiro, lasso, bicyclic), size and composition. These interaction energies have been used within the framework of the Quantum Cluster Equilibrium Theory (QCE) to calculate cluster populations as well as thermodynamic properties of binary methanol-water mixtures spanning the whole range from pure water to pure methanol. The necessary parameters amf and bxv of the QCE model were obtained by fitting to experimental isobars of MeOH-H2O mixtures with different MeOH content. The cubic and spiro motifs dominate the distribution of methanol-water clusters in the mixtures with a maximum of mixed clusters at x(MeOH) = 0.365. Reasonable agreement with experimental data as well as earlier molecular dynamics simulations was found for excess enthalpies H(E), entropies S(E) as well as Gibbs free energies of mixing G(E). In contrast, heat capacities Cp and C showed only poor agreement with experimental data. PMID:25660666

  3. Microstructural Response During Isothermal and Isobaric Loading of a Precipitation-Strengthened Ni-29.7Ti-20Hf High-Temperature Shape Memory Alloy

    NASA Astrophysics Data System (ADS)

    Benafan, O.; Noebe, R. D.; Padula, S. A.; Vaidyanathan, R.

    2012-12-01

    A stable Ni-rich Ni-29.7Ti-20Hf (at. pct) shape memory alloy, with relatively high transformation temperatures, was shown to exhibit promising properties at lower raw material cost when compared to typical NiTi-X (X = Pt, Pd, Au) high-temperature shape memory alloys (HTSMAs). The excellent dimensional stability and high work output for this alloy were attributed to a coherent, nanometer size precipitate phase observed using transmission electron microscopy. To establish an understanding of the role of these precipitates on the microstructure and ensuing stability of the NiTiHf alloy, a detailed study of the micromechanical and microstructural behaviors was performed. In-situ neutron diffraction at stress and temperature was used to obtain quantitative information on phase-specific internal strain, texture, and phase volume fractions during both isothermal and isobaric testing of the alloy. During isothermal testing, the alloy exhibited low isothermal strains due to limited detwinning, consistent with direct measurements of the bulk texture through neutron diffraction. This limited detwinning was attributed to the pinning of twin and variant boundaries by the dispersion of fine precipitates. During isobaric thermal cycling at 400 MPa, the high work output and near-perfect dimensional stability was attributed to the presence of the precipitates that act as homogeneous sources for the nucleation of martensite throughout the material, while providing resistance to irrecoverable processes such as plastic deformation.

  4. Thermodynamic equilibrium at heterogeneous pressure

    NASA Astrophysics Data System (ADS)

    Vrijmoed, Johannes C.; Podladchikov, Yuri Y.

    2014-05-01

    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).

  5. Local non-equilibrium thermodynamics.

    PubMed

    Jinwoo, Lee; Tanaka, Hajime

    2015-01-01

    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

  6. String fluid in local equilibrium

    NASA Astrophysics Data System (ADS)

    Schubring, Daniel; Vanchurin, Vitaly

    2014-10-01

    We study the solutions of string fluid equations under the assumption of a local equilibrium which was previously obtained in the context of the kinetic theory. We show that the fluid can be foliated into noninteracting submanifolds whose equations of motion are exactly that of the wiggly strings considered previously by Vilenkin and Carter. In a special case of negligible statistical variance in either the left- or the right-moving directions of microscopic strings, the submanifolds are described by the action of a null-current-carrying chiral string. When both variances vanish the submanifolds are described by the Nambu-Goto action and the string fluid reduces to the string dust introduced by Stachel.

  7. Neoclassical equilibrium in gyrokinetic simulations

    SciTech Connect

    Garbet, X.; Dif-Pradalier, G.; Nguyen, C.; Sarazin, Y.; Grandgirard, V.; Ghendrih, Ph. [CEA, IRFM, F-13108 St. Paul-lez-Durance Cedex (France)

    2009-06-15

    This paper presents a set of model collision operators, which reproduce the neoclassical equilibrium and comply with the constraints of a full-f global gyrokinetic code. The assessment of these operators is based on an entropy variational principle, which allows one to perform a fast calculation of the neoclassical diffusivity and poloidal velocity. It is shown that the force balance equation is recovered at lowest order in the expansion parameter, the normalized gyroradius, hence allowing one to calculate correctly the radial electric field. Also, the conventional neoclassical transport and the poloidal velocity are reproduced in the plateau and banana regimes. The advantages and drawbacks of the various model operators are discussed in view of the requirements for neoclassical and turbulent transport.

  8. Local non-equilibrium thermodynamics

    E-print Network

    Lee Jinwoo; Hajime Tanaka

    2015-01-16

    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.

  9. Characteristics of equilibrium reaction of zolazepam.

    PubMed

    Hong, W H; Szulczewski, D H

    1981-06-01

    The equilibrium reaction of zolazepam, a pyrazolodiazepinone, was studied and analyzed using the approach used previously for other pyrazolodiazepinone derivatives. The intrinsic ring closure equilibrium constant for this reaction was approximately 100 times larger than that observed for pyrazolodiazepinones studied previously. This study illustrates that the diazepinone ring can dominate in equilibrium mixtures formed at pH values far below the pKa of the corresponding form. PMID:7252822

  10. Depletion forces in non-equilibrium

    E-print Network

    J. Dzubiella; H. Lowen; C. N. Likos

    2003-06-03

    The concept of effective depletion forces between two fixed big colloidal particles in a bath of small particles is generalized to a non-equilibrium situation where the bath of small Brownian particles is flowing around the big particles with a prescribed velocity. In striking contrast to the equilibrium case, the non-equilibrium forces violate Newton's third law, are non-conservative and strongly anisotropic, featuring both strong attractive and repulsive domains.

  11. Passive equilibrium studies on ZT-P

    SciTech Connect

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

    1987-12-01

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

  12. 1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO

    SciTech Connect

    T. EVANS; ET AL

    2000-08-01

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

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

    E-print Network

    Beretta, Gian Paolo

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

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

    E-print Network

    Fiat, Amos

    2 Equilibrium The theory of equilibrium attempts to predict what happens in a game when players over games to find games with good equilibria. Here, we review the most fundamental notions of equilibrium. They will all be static notions in that players are assumed to understand the game and will play

  15. The Equilibrium of Life-Career Planning

    NASA Astrophysics Data System (ADS)

    Byars-Winston, Angela

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

  16. Pretirage INLN..... Non equilibrium statistical mechanics

    E-print Network

    Paris-Sud XI, Université de

    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

  17. Refinements of the Nash equilibrium concept

    Microsoft Academic Search

    R. B. Myerson

    1978-01-01

    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.

  18. Wetting under chemical equilibrium and nonequilibrium conditions

    Microsoft Academic Search

    I. A. Aksay; Carl E. Hoge; Joseph A. Pask

    1974-01-01

    The thermodynamics of a solid-liquid-vapor system both under chemical equilibrium and nonequilibrium conditions, based on the model of Gibbs, is discussed. Under chemical equilibrium conditions, the degree of wetting or nonwetting of a flat and nondeformable solid by the liquid is defined by Young's equation in terms of the static interfacial tensions. Under chemical nonequilibrium conditions, mass transfer across an

  19. Chemical equilibrium systems as numerical test problems

    Microsoft Academic Search

    Keith Meintjes; Alexander P. Morgan

    1990-01-01

    A system of nonlinear equations has been used as a test case by at least two authors. This system is purported to describe the equilibrium of the products of hydrocarbon combustion. The given system does not describe the stated physical problem, a fact which invalidates it as a test of solution methods for chemical equilibrium systems. In this note, the

  20. Diphasic equilibrium and chemical engineering Francois JAMES

    E-print Network

    d'Orléans, Université

    Diphasic equilibrium and chemical engineering Fran¸cois JAMES Mathematical topics in fluid ). (2) This equality is nothing but the well-known equality of chemical potentials at equilibrium. We. Tech., Harlow, 1992, 246-250 1 Introduction Many processes in Chemical Engineering involve matter

  1. Spheromak Equilibrium Studies on SSX Cameron Geddes

    E-print Network

    Geddes, Cameron Guy Robinson

    in place by a copper flux conserver. This configuration is illustrated in figure 1. The present experiment obtained at low aspect ratio (that is, little or no central structure). The study of spheromak equilibrium on SSX is a program involving experimental measurements, theory and simulation on spheromak equilibrium

  2. Sensitivity theory for the equilibrium burnup cycle

    Microsoft Academic Search

    W. S. Yang; T. J. Downar

    1989-01-01

    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.

  3. Limitations of Equilibrium What if LS adj?

    E-print Network

    Plant, Robert

    Limitations of Equilibrium Or: What if LS adj? Bob Plant, Laura Davies Department of Meteorology / implications What if LS adj? ­ p.1/3 #12;Timescale Separation What if LS adj? ­ p.2/3 #12;Adjustment-equilibrium thinking is that LS adj Parameterizations often include some such adjustment timescale in computing

  4. Measuring the equilibrium real interest rate

    Microsoft Academic Search

    Alejandro Justiniano; Giorgio E. Primiceri

    2010-01-01

    The equilibrium real interest rate represents the real rate of return required to keep the economy’s output equal to potential output. This article discusses how to measure the equilibrium real interest rate, using an empirical structural model of the economy.

  5. PUBLISHED VERSION Edge equilibrium code for tokamaks

    E-print Network

    PUBLISHED VERSION Edge equilibrium code for tokamaks Xujing Li, Leonid E. Zakharov, and Vladimir V=pdfcov Published by the AIP Publishing This article is copyrighted as indicated in the article. Reuse of AIP December 2013; published online 9 January 2014) The edge equilibrium code (EEC) described in this paper

  6. 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.)

  7. Partial equilibrium approximations in Apoptosis

    E-print Network

    Huang, Ya-Jing

    2012-01-01

    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 ...

  8. Disturbances in equilibrium function after major earthquake

    PubMed Central

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

    2012-01-01

    Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events. PMID:23087814

  9. Novel and cost-effective 6-plex isobaric tagging reagent, DiART, is effective for identification and relative quantification of complex protein mixtures using PQD fragmentation.

    PubMed

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

    2013-09-01

    Deuterium isobaric Amine Reactive Tag (DiART) reagents facilitate relative quantification during proteomic analysis in a functionally similar manner to commercially available isobaric tag for relative and absolute quantitation (iTRAQ) and tandem mass tag (TMT) reagents. In contrast to iTRAQ and TMT, DiART reagents incorporate deuterium isotopes which significantly reduce the number of required synthesis steps and hence have potential to significantly reduce reagent production cost. We examined the capability of DiART for performing quantitative proteomic experiments using a linear ion-trap mass spectrometer with Pulsed Q Dissociation (PQD) fragmentation. Using a synthetic peptide tagged with DiART reagent, we observed a precise mass shift of 144.79?Da on the triply charged precursor ion, which shows complete derivatization of the N-terminus and ?-amino group of lysine. A DiART tagged tryptic digest of bovine serum albumin showed a sequence coverage of 57.99% which was very comparable to that showed by iTRAQ, 54.77%. Furthermore, a ten protein mixture tagged with DiART reagents and mixed in 1:1:1:1:1:1 exhibited?

  10. 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)

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

    2012-04-01

    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.

  11. A Thermodynamic Property Model for R-125/143a Mixtures Based on a New Cubic Equation of State

    NASA Astrophysics Data System (ADS)

    Zhang, Heng-Liang; Tada, Satoru; Waranabe, Koichi

    The binary mixture of two hydrofluorocarbons, R-125 and R-143a, behaves almost like an azeotrope and has been considered as a promising refrigerant to substitute R-502. In this paper, we present a thermodynamic property model for the R-125/143a system, which was developed on the basis of a new cubic equation of state proposed in our previous publications. The essential thermodynamic properties such as PVTx properties, vapor-liquid equilibrium, enthalpy, entropy, isobaric specific heat, and speed of sound are well represented simultaneously by the new model in the entire fluid-phase of theR-125/143a system including the pure components.The model is valid for any composition with thermodynamic consistency to cover a range broad enough for refrigeration engineering applications. A pressure-enthalpy diagram for the R-125/143a mixture with 50 mass% R-125 is also presented.

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

    NASA Astrophysics Data System (ADS)

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

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

  13. The Conceptual Change Approach to Teaching Chemical Equilibrium

    ERIC Educational Resources Information Center

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

    2006-01-01

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

  14. On the concept chemical equilibrium: The associative framework

    Microsoft Academic Search

    Esther Gussarsky; Malka Gorodetsky

    1990-01-01

    Word associations were used to map the conception of high school students concerning the concepts chemical equilibrium and equilibrium. It was found that the preconception of the two concepts was differentiated on noncritical dimensions; equilibrium being associated with everyday life experiences and chemical equilibrium with general chemical concepts. After studying the subject of chemical equilibrium at school the two concepts

  15. Local Nash Equilibrium in Social Networks

    PubMed Central

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

    2014-01-01

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

  16. Local Nash equilibrium in social networks.

    PubMed

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

    2014-01-01

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

  17. Equilibrium reaction of pyrazolodiazepinones in aqueous solution.

    PubMed

    Hong, W H; Johnston, C; Szulczewski, D

    1977-12-01

    This study of the behavior of some pyrazolodiazepinones in aqueous solution at near ambient temperature indicated that they form stable equilibrium mixtures consisting of ring and opened forms. Under isothermal conditions, mixtures are produced whose composition is dependent on pH and may vary from that corresponding to essentially complete ring opening to complete closure. Ring closure equilibrium constants were calculated, and the influence of methyl substitution was determined. Substitution of a methyl group for an amido hydrogen in the open form results in a fivefold increase in this constant. Methylation of the terminal amino group, however, did not cause a corresponding increase and may not significantly affect equilibrium. PMID:925934

  18. Electric Current Equilibrium in the Corona

    NASA Astrophysics Data System (ADS)

    Filippov, Boris

    2013-04-01

    A hyperbolic flux-tube configuration containing a null point below the flux rope is considered as a pre-eruptive state of coronal mass ejections that start simultaneously with flares. We demonstrate that this configuration is unstable and cannot exist for a long time in the solar corona. The inference follows from general equilibrium conditions and from analyzing simple models of the flux-rope equilibrium. A direct consequence of the stable flux-rope equilibrium in the corona are separatrices in the horizontal-field distribution in the chromosphere. They can be recognized as specific "herring-bone structures" in a chromospheric fibril pattern.

  19. Energy Spectrum of equilibrium Black Holes

    E-print Network

    Abhishek Majhi

    2014-09-20

    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.

  20. Support of the extremal measure in a vector equilibrium problem

    NASA Astrophysics Data System (ADS)

    Lapik, M. A.

    2006-08-01

    A generalization of the Mhaskar-Saff functional is obtained for a vector equilibrium problem with an external field. As an application, the supports of the equilibrium measures are found in a special vector equilibrium problem with Nikishin matrix.

  1. Title of dissertation: MAGNETOHYDRODYNAMIC EQUILIBRIUM AND STABILITY OF

    E-print Network

    Anlage, Steven

    ABSTRACT Title of dissertation: MAGNETOHYDRODYNAMIC EQUILIBRIUM AND STABILITY OF CENTRIFUGALLY instability could reinforce centrifugal confinement. #12;MAGNETOHYDRODYNAMIC EQUILIBRIUM AND STABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3 Resistive Magnetohydrodynamic Equilibrium and Sta- bility of a Rotating Plasma with Particle

  2. Radiative-dynamical equilibrium states for Jupiter

    NASA Technical Reports Server (NTRS)

    Trafton, L. M.; Stone, P. H.

    1974-01-01

    In order to obtain accurate estimates of the radiative heating that drives motions in Jupiter's atmosphere, previous radiative equilibrium calculations are improved by including the NH3 opacities and updated results for the pressure-induced opacities. These additions increase the radiative lapse rate near the top of the statically unstable region and lead to a fairly constant radiative lapse rate below the tropopause. The radiative-convective equilibrium temperature structure consistent with these changes is calculated, but it differs only slightly from earlier calculations. The radiative equilibrium calculations are used to calculate whether equilibrium states can occur on Jupiter which are similar to the baroclinic instability regimes on the earth and Mars. The results show that Jupiter's dynamical regime cannot be of this kind, except possibly at very high latitudes, and that its regime must be a basically less stable one than this kind.

  3. Area Traffic Control and Network Equilibrium

    E-print Network

    Gartner, Nathan H.

    Area traffic control systems play an important role in determining the equilibrium between demand and supply in an urban highway network. The paper describes some of the methods that have been developed for the operation ...

  4. An Equilibrium Model of Rare Event Premia

    E-print Network

    Liu, Jun

    2002-08-12

    In this paper, we study the asset pricing implication of imprecise knowledge about rare events. Modeling rare events as jumps in the aggregate endowment, we explicitly solve the equilibrium asset prices in a pure-exchange ...

  5. Adaptive radiation: convergence and non-equilibrium.

    PubMed

    Gillespie, Rosemary G

    2013-01-21

    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

  6. Stochastic approach to equilibrium and nonequilibrium thermodynamics

    NASA Astrophysics Data System (ADS)

    Tomé, Tânia; de Oliveira, Mário J.

    2015-04-01

    We develop the stochastic approach to thermodynamics based on stochastic dynamics, which can be discrete (master equation) and continuous (Fokker-Planck equation), and on two assumptions concerning entropy. The first is the definition of entropy itself and the second the definition of entropy production rate, which is non-negative and vanishes in thermodynamic equilibrium. Based on these assumptions, we study interacting systems with many degrees of freedom in equilibrium or out of thermodynamic equilibrium and how the macroscopic laws are derived from the stochastic dynamics. These studies include the quasiequilibrium processes; the convexity of the equilibrium surface; the monotonic time behavior of thermodynamic potentials, including entropy; the bilinear form of the entropy production rate; the Onsager coefficients and reciprocal relations; and the nonequilibrium steady states of chemical reactions.

  7. An Elementary Discussion of Chemical Equilibrium.

    ERIC Educational Resources Information Center

    David, Carl W.

    1988-01-01

    This discussion uses a more difficult reaction as the prototype to derive the standard equation for chemical equilibrium. It can be used by students who can understand and use partial derivatives. (CW)

  8. Spreadsheet Templates for Chemical Equilibrium Calculations.

    ERIC Educational Resources Information Center

    Joshi, Bhairav D.

    1993-01-01

    Describes two general spreadsheet templates to carry out all types of one-equation chemical equilibrium calculations encountered by students in undergraduate chemistry courses. Algorithms, templates, macros, and representative examples are presented to illustrate the approach. (PR)

  9. Inventories and capacity utilization in general equilibrium 

    E-print Network

    Trupkin, Danilo Rogelio

    2009-05-15

    The primary goal of this dissertation is to gain a better understanding, in thecontext of a dynamic stochastic general equilibrium framework, of the role of inventories and capacity utilization (of both capital and labor) and, in particular...

  10. Non-equilibrium in adsorbed polymer layers

    Microsoft Academic Search

    Ben O’Shaughnessy; Dimitrios Vavylonis

    2005-01-01

    High molecular weight polymer solutions have a powerful tendency to deposit adsorbed layers when exposed to even mildly attractive surfaces. The equilibrium properties of these dense interfacial layers have been extensively studied theoretically. A large body of experimental evidence, however, indicates that non-equilibrium effects are dominant whenever monomer-surface sticking energies are somewhat larger than kT, a common case. Polymer relaxation

  11. Theory for non-equilibrium statistical mechanics.

    PubMed

    Attard, Phil

    2006-08-21

    This paper reviews a new theory for non-equilibrium statistical mechanics. This gives the non-equilibrium analogue of the Boltzmann probability distribution, and the generalization of entropy to dynamic states. It is shown that this so-called second entropy is maximized in the steady state, in contrast to the rate of production of the conventional entropy, which is not an extremum. The relationships of the new theory to Onsager's regression hypothesis, Prigogine's minimal entropy production theorem, the Langevin equation, the formula of Green and Kubo, the Kawasaki distribution, and the non-equilibrium fluctuation and work theorems, are discussed. The theory is worked through in full detail for the case of steady heat flow down an imposed temperature gradient. A Monte Carlo algorithm based upon the steady state probability density is summarized, and results for the thermal conductivity of a Lennard-Jones fluid are shown to be in agreement with known values. Also discussed is the generalization to non-equilibrium mechanical work, and to non-equilibrium quantum statistical mechanics. As examples of the new theory two general applications are briefly explored: a non-equilibrium version of the second law of thermodynamics, and the origin and evolution of life. PMID:16883388

  12. IONIZATION EQUILIBRIUM TIMESCALES IN COLLISIONAL PLASMAS

    SciTech Connect

    Smith, Randall K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Hughes, John P., E-mail: rsmith@cfa.harvard.ed, E-mail: jph@physics.rutgers.ed [Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854-8019 (United States)

    2010-07-20

    Astrophysical shocks or bursts from a photoionizing source can disturb the typical collisional plasma found in galactic interstellar media or the intergalactic medium. The spectrum emitted by this plasma contains diagnostics that have been used to determine the time since the disturbing event, although this determination becomes uncertain as the elements in the plasma return to ionization equilibrium. A general solution for the equilibrium timescale for each element arises from the elegant eigenvector method of solution to the problem of a non-equilibrium plasma described by Masai and Hughes and Helfand. In general, the ionization evolution of an element Z in a constant electron temperature plasma is given by a coupled set of Z + 1 first-order differential equations. However, they can be recast as Z uncoupled first-order differential equations using an eigenvector basis for the system. The solution is then Z separate exponential functions, with the time constants given by the eigenvalues of the rate matrix. The smallest of these eigenvalues gives the scale of the slowest return to equilibrium independent of the initial conditions, while conversely the largest eigenvalue is the scale of the fastest change in the ion population. These results hold for an ionizing plasma, a recombining plasma, or even a plasma with random initial conditions, and will allow users of these diagnostics to determine directly if their best-fit result significantly limits the timescale since a disturbance or is so close to equilibrium as to include an arbitrarily long time.

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

    E-print Network

    Fiat, Amos

    Chapter 2 Equilibrium The theory of equilibrium attempts to predict what happens in a game when to consult a game theory textbook. 2.1 Complete Information Games In games of compete information all players are optimizing over games to find the games with good equilibria. Here, we review the most fundamental notions

  14. Non--Equilibrium Blunt Body Flow 1 Analysis of NonEquilibrium, Hypersonic Blunt

    E-print Network

    Non--Equilibrium Blunt Body Flow 1 Analysis of Non­Equilibrium, Hypersonic Blunt Body Flow streamline quantities and the stagnation point heat transfer in hypersonic flows about spheres or cylinders, as two-- dimensional hypersonic flows about spheres or cylinders exhibit an approximate local similarity

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

    E-print Network

    Ihee, Hyotcherl

    the equilibrium expression relative to its standard reference state. #12;Example 9.3 · Hypochlorous acid (HOCl equation for this process is 2 Cl2(g) + 2 HgO(s) + H2O(l) HgO×HgCl2(s) + 2 HOCl(aq) Write the equilibrium

  16. Misconceptions of students and teachers in chemical equilibrium

    Microsoft Academic Search

    Anil C. Banerjee

    1991-01-01

    A written test was developed and administered to diagnose misconceptions in different areas of chemical equilibrium among 162 undergraduate chemistry students and 69 school?teachers of chemistry. Analysis of the responses reveal widespread misconceptions among both students and teachers in areas related to the prediction of equilibrium conditions, rate and equilibrium, applying equilibrium principles to daily life, and to acid?base and

  17. 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

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

    2014-01-01

    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

  18. First and Second-Phase Transitions of Gases at Isobaric Process; Lennard-Jones (9,6) Gases with a Hard Core

    NASA Astrophysics Data System (ADS)

    Matsumoto, Akira

    2014-12-01

    The thermodynamic functions for Lennard-Jones (9,6) gases with a hard core that are evaluated till the third virial coefficients, are investigated at an isobaric process. Some thermodynamic functions are analytically expressed as functions of intensive variables, temperature, and pressure. Some thermodynamic quantities for carbon dioxide are calculated numerically and drawn graphically. In critical states, the heat capacity diverges to infinity at the critical point while the Gibbs free energy, volume, enthalpy, and entropy are continuous at the critical point. In the coexistence of two phases, the boiling temperatures and the enthalpy changes of vaporization are obtained by numerical calculations for 20 substances. The Gibbs free energy indicates a polygonal line; entropy, volume, and enthalpy jump from the liquid to gaseous phase at the boiling point. The heat capacity does not diverge to infinity but shows a finite discrepancy at boiling point. This suggests that a first-order phase transition at the boiling point and a second-order phase transition may occur at the critical point.

  19. Isospin mixing of the isobaric analog state studied in a high-resolution 56Fe(3He,t)56Co reaction

    NASA Astrophysics Data System (ADS)

    Fujita, H.; Fujita, Y.; Adachi, T.; Akimune, H.; Botha, N. T.; Hatanaka, K.; Matsubara, H.; Nakanishi, K.; Neveling, R.; Okamoto, A.; Sakemi, Y.; Shima, T.; Shimizu, Y.; Smit, F. D.; Suzuki, T.; Tamii, A.; Yosoi, M.

    2013-11-01

    High-energy-resolution 56Fe(3He,t)56Co reaction measurements were performed at forward angles including 0?. From the spectra obtained, the splitting of the Fermi transition strength and thus the isospin mixing between the J?=0+ isobaric analog state (IAS) at 3.60 MeV and a neighboring 0+ state at 3.53 MeV have been investigated. In order to distinguish between states excited in Fermi and Gamow-Teller (GT) transitions, the measurements were performed at two 3He beam energies of 140 and 100 MeV/nucleon. Owing to the different incident energy dependencies of the ??- and ?-type effective interaction strengths, it is expected that the Fermi transitions are stronger relative to GT transitions at lower beam energies. Therefore the excitation of a state by the Fermi transition could be identified by the ?L=0 angular distribution and the ratio of transition strengths at these two incident energies. In the energy region around the IAS at 3.60 MeV, it was found that the state at 3.53 MeV is also excited by the Fermi transition and thus it has J? values of 0+. A value of 32.3(5) keV could be deduced for the off-diagonal matrix element of the Hamiltonian that causes the isospin mixing. A corresponding isospin impurity of 28±1% was obtained.

  20. Isobar-model partial-wave analysis of ?N-->??N in the c.m. energy range 1320-1930 MeV

    NASA Astrophysics Data System (ADS)

    Manley, D. Mark; Arndt, Richard A.; Goradia, Yogesh; Teplitz, Vigdor L.

    1984-09-01

    We study the reactions ?N-->??N in the center-of-mass energy range 1320-1930 MeV within the framework of the isobar model. The present analysis includes over 30% more events than the most extensive previous analysis. Data for ?-p-->?+?-n, ?-p-->?0?-p, ?+p-->?0?+p, and ?+p-->?+?+n are simultaneously fitted assuming production of ?, ?, ?(P33) and N*(P11). The cross section for ?-p-->?0?0n is predicted and found to be in good agreement with experiment. ?N-->?N* amplitudes for I=12 are investigated for the first time. We confirm the existence of a significant ?N* decay for the second P33 resonance and determine that ?N* is the dominant inelastic channel for the P31 partial wave. The ?N decay of the G17 wave is observed for the first time. Evidence is found for unestablished resonances near 1900 MeV in the S11, P11, P13, and F15 partial waves. We also discuss evidence for a second F35 resonance. Signs of resonant amplitudes determined from this analysis are compared with results of previous analyses and with predictions from several models.

  1. Nuclear structure beyond the neutron drip line: the lowest energy states in $^9$He via their T=5/2 isobaric analogs in $^9$Li

    E-print Network

    Uberseder, E; Goldberg, V Z; Koshchiy, E; Roeder, B T; Alcorta, M; Chubarian, G; Davids, B; Fu, C; Hooker, J; Jayatissa, H; Melconian, D; Tribble, R E

    2015-01-01

    The level structure of the very neutron rich and unbound $^9$He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy $^9$He states exist with spins $J^\\pi=1/2^+$ and $J^\\pi=1/2^-$ and widths on the order of hundreds of keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the $^8$He$+n$ system, performed via a search for the T=5/2 isobaric analog states in $^9$Li populated through $^8$He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad $J^{\\pi}=1/2^+$ state in $^9$He located approximately 3 MeV above the neutron decay threshold.

  2. Nuclear structure beyond the neutron drip line: the lowest energy states in $^9$He via their T=5/2 isobaric analogs in $^9$Li

    E-print Network

    E. Uberseder; G. V. Rogachev; V. Z. Goldberg; E. Koshchiy; B. T. Roeder; M. Alcorta; G. Chubarian; B. Davids; C. Fu; J. Hooker; H. Jayatissa; D. Melconian; R. E. Tribble

    2015-04-03

    The level structure of the very neutron rich and unbound $^9$He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy $^9$He states exist with spins $J^\\pi=1/2^+$ and $J^\\pi=1/2^-$ and widths on the order of hundreds of keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the $^8$He$+n$ system, performed via a search for the T=5/2 isobaric analog states in $^9$Li populated through $^8$He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad $J^{\\pi}=1/2^+$ state in $^9$He located approximately 3 MeV above the neutron decay threshold.

  3. Analytic prediction of airplane equilibrium spin characteristics

    NASA Technical Reports Server (NTRS)

    Adams, W. M., Jr.

    1972-01-01

    The nonlinear equations of motion are solved algebraically for conditions for which an airplane is in an equilibrium spin. Constrained minimization techniques are employed in obtaining the solution. Linear characteristics of the airplane about the equilibrium points are also presented and their significance in identifying the stability characteristics of the equilibrium points is discussed. Computer time requirements are small making the method appear potentially applicable in airplane design. Results are obtained for several configurations and are compared with other analytic-numerical methods employed in spin prediction. Correlation with experimental results is discussed for one configuration for which a rather extensive data base was available. A need is indicated for higher Reynolds number data taken under conditions which more accurately simulate a spin.

  4. Phase Equilibrium Measurements of Sacha Inchi Oil ( Plukenetia volubilis ) and CO 2 at High Pressures

    Microsoft Academic Search

    Ivor M. do Prado; Willyan M. Giufrida; Víctor H. Alvarez; Vladimir F. Cabral; Sócrates Quispe-Condori; Marleny D. A. Saldaña; Lucio Cardozo-Filho

    New data on phase equilibria for Sacha inchi seed oil in carbon dioxide have been measured using a variable volume cell phase\\u000a equilibria system at temperatures of 303, 313 and 323 K and at pressures ranging from 4.3 to 27.7 MPa. The CO2 mole fraction varied from 0.7488 to 0.9997. At the studied concentrations, phase transitions of vapor-liquid, liquid-liquid-vapor\\u000a and liquid-liquid were

  5. Algorithm For Hypersonic Flow In Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Palmer, Grant

    1989-01-01

    Implicit, finite-difference, shock-capturing algorithm calculates inviscid, hypersonic flows in chemical equilibrium. Implicit formulation chosen because overcomes limitation on mathematical stability encountered in explicit formulations. For dynamical portion of problem, Euler equations written in conservation-law form in Cartesian coordinate system for two-dimensional or axisymmetric flow. For chemical portion of problem, equilibrium state of gas at each point in computational grid determined by minimizing local Gibbs free energy, subject to local conservation of molecules, atoms, ions, and total enthalpy. Major advantage: resulting algorithm naturally stable and captures strong shocks without help of artificial-dissipation terms to damp out spurious numerical oscillations.

  6. Computing Properties Of Chemical Mixtures At Equilibrium

    NASA Technical Reports Server (NTRS)

    Mcbride, B. J.; Gordon, S.

    1995-01-01

    Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.

  7. Pions in and out of equilibrium

    SciTech Connect

    Gavin, S.

    1991-12-01

    Can final state scattering wrestle the secondaries in nucleus-nucleus collisions into a fluid state near local thermal equilibrium? What do the pion p{sub T} spectra measured in pp, pA and SPS light ion experiments already tell us about the approach to equilibrium? To begin to address these questions, we must face the nonequilibrium nature of hadronic evolution in the late stages of these collisions. I will outline efforts to apply transport theory to the nonequilibrium pion fluid at midrapidity focusing on two phenomena: partial thermalization and pion conservation.

  8. Pions in and out of equilibrium

    SciTech Connect

    Gavin, S.

    1991-12-01

    Can final state scattering wrestle the secondaries in nucleus-nucleus collisions into a fluid state near local thermal equilibrium What do the pion p{sub T} spectra measured in pp, pA and SPS light ion experiments already tell us about the approach to equilibrium To begin to address these questions, we must face the nonequilibrium nature of hadronic evolution in the late stages of these collisions. I will outline efforts to apply transport theory to the nonequilibrium pion fluid at midrapidity focusing on two phenomena: partial thermalization and pion conservation.

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

    E-print Network

    Plant, Robert

    What's quasi-equilibrium all about? WhatWhatWhat'''s quasis quasis quasi---equilibrium need to be removed. This suggests `memory' within the system. Control run: Applying constant surface fluxes until equilibrium achieved A long time Repeating 3hr cycles #12;Equilibrium response Decay

  10. Coupled phase and aqueous species equilibrium of the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite

    NASA Astrophysics Data System (ADS)

    Duan, Zhenhao; Li, Dedong

    2008-10-01

    A model is developed for the calculation of coupled phase and aqueous species equilibrium in the H 2O-CO 2-NaCl-CaCO 3 system from 0 to 250 °C, 1 to 1000 bar with NaCl concentrations up to saturation of halite. The vapor-liquid-solid (calcite, halite) equilibrium together with the chemical equilibrium of H +, Na +, Ca 2+, CaHCO3+, Ca(OH) +, OH -, Cl -, HCO3-, CO32-, CO 2(aq) and CaCO 3(aq) in the aqueous liquid phase as a function of temperature, pressure, NaCl concentrations, CO 2(aq) concentrations can be calculated, with accuracy close to those of experiments in the stated T- P- m range, hence calcite solubility, CO 2 gas solubility, alkalinity and pH values can be accurately calculated. The merit and advantage of this model is its predictability, the model was generally not constructed by fitting experimental data. One of the focuses of this study is to predict calcite solubility, with accuracy consistent with the works in previous experimental studies. The resulted model reproduces the following: (1) as temperature increases, the calcite solubility decreases. For example, when temperature increases from 273 to 373 K, calcite solubility decreases by about 50%; (2) with the increase of pressure, calcite solubility increases. For example, at 373 K changing pressure from 10 to 500 bar may increase calcite solubility by as much as 30%; (3) dissolved CO 2 can increase calcite solubility substantially; (4) increasing concentration of NaCl up to 2 m will increase calcite solubility, but further increasing NaCl solubility beyond 2 m will decrease its solubility. The functionality of pH value, alkalinity, CO 2 gas solubility, and the concentrations of many aqueous species with temperature, pressure and NaCl (aq) concentrations can be found from the application of this model. Online calculation is made available on www.geochem-model.org/models/h2o_co2_nacl_caco3/calc.php.

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

    SciTech Connect

    Robinson, R.L. Jr.

    1990-01-01

    The effective design and operation of processes for conversion of coal to fluid fuels require accurate knowledge of the phase behavior of the fluid mixtures encountered in the conversion processes. Multiple phases are present in essentially all stages of feed preparation, conversion reactions, and product separation; knowledge of the behavior of these multiple phases is important in each step. The overall objective of the author's work is to develop accurate predictive methods for representation of vapor-liquid equilibria in systems encountered in coal-conversion processes. During the present report period, our solubility apparatus was modified to accommodate methane mixtures and to expedite data acquisition. The modifications resulted in a number of improvements including: improved mixing, low dead volume, and improved design and procedures for cleaning and degassing. Data have been obtained on the solubility of methane in cyclohexane and in benzene at 323.1, 373.1 and 423.1 K. These data are well described by the Soave and Peng-Robinson equations of state. 19 refs., 2 figs., 4 tabs.

  12. Equilibrium rotation in field-reversed configurations

    SciTech Connect

    Steinhauer, Loren [Redmond Plasma Physics Laboratory, University of Washington, 4700 N. E. 95th Street, Suite 100, Redmond, Washington 98052 (United States)

    2008-01-15

    The turbulence that drives anomalous transport in field-reversed configurations (FRCs) is believed to break the otherwise closed magnetic surfaces inside the separatrix. This places electrons in the core of the plasma in electrical contact with those in the periphery. This effect was proposed and investigated in the context of spheromaks [D. D. Ryutov, Phys. Plasmas 14, 022506 (2007)]. The opening up of internal magnetic field lines serves to regulate the electrostatic potential in the interior of the plasma, and in turn drives ion rotation. In effect, 'end-shorting', a well-known phenomenon in the FRC scrape-off layer, also extends into the plasma interior. For conditions relevant to experiments, the ion rotation can be expressed in terms of equilibrium properties (density and temperature gradients) and as such is the 'equilibrium' rotation. This theory is incomplete in that it neglects evolving, transport-related effects that modify the equilibrium and, indirectly, the rotation rate. Consequently, the equilibrium rotation theory is only partially successful in predicting experimental results: although it predicts the average rotation well, the estimated degree of rotational shear seems unlikely, especially at late times in the plasma lifetime.

  13. The magnetohydrodynamic equilibrium of coronal helmet streamers

    Microsoft Academic Search

    S. Cuperman; C. Bruma; M. Dryer; M. Semel

    1995-01-01

    The equilibrium of coronal helmet streamers is investigated within the framework of an axisymmetric magnetohydrodynamic polytropic model. The main features of this work are: (i) The eight MHD vector equations are reduced - via analytical manipulations - to three scalar equations involving the magnetic flux function, the current density and temperature; (ii) The reduced system of equations is solved by

  14. Problems on Non-Equilibrium Statistical Physics 

    E-print Network

    Kim, Moochan

    2011-08-08

    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...

  15. Dynamic Equilibrium of the Housing Market

    Microsoft Academic Search

    Raymond Y. C. Tse; James R. Webb

    1999-01-01

    Summary. This paper, derived within a general equilibrium framework, demonstrates that housing price can be explicitly expressed as a combination of an exponential and linear function of housing rental. This model provides an explanation as to why housing appreciation may not match ination in the long-run steady state. We show that only under a very particular set of conditions, will

  16. OPTIMAL CONGESTION CHARGES IN GENERAL EQUILIBRIUM

    Microsoft Academic Search

    Dong-Joo MOON

    This paper deals with pricing and investment decision problems of multi-route and multi-period highway systems in which the congestion is a significant factor in the assessment of system costs. This study approaches this congestion pricing scheme with two different social welfare maximi- zation problems, both of which search for the optimal solutions through general equilibrium analysis. These two optimization problems

  17. Detection of punctuated equilibrium from molecular phylogenies

    Microsoft Academic Search

    F. B OKMA

    2002-01-01

    The theory of punctuated equilibrium hypothesises that most morphological change in species takes place in rapid bursts triggered by speciation. Eldregde and Gould postulated the theory in 1972, as an alternative to the idea that morphological change slowly accumulates in the course of time, a then common belief they dubbed phyletic gradualism. Ever since its introduction the theory of punctuated

  18. A theoretical analysis of vertical flow equilibrium

    Microsoft Academic Search

    Y. C. Yortsos

    1995-01-01

    The assumption of Vertical Equilibrium (VE) and of parallel flow conditions, in general, is often applied to the modeling of flow and displacement in natural porous media. However, the methodology for the development of the various models is rather intuitive, and no rigorous method is currently available. In this paper, we develop an asymptotic theory using as parameter the variable

  19. The 'Schwarzschild-Kerr' Equilibrium Configurations

    SciTech Connect

    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

    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.

  20. Putting A Human Face on Equilibrium

    Microsoft Academic Search

    Neil Glickstein

    2005-01-01

    A short biography of chemist Fritz Haber is used to personalize the abstract concepts of equilibrium chemistry for high school students in an introductory course. In addition to giving the Haber Bosch process an historic, an economic, and a scientific background the reading and subsequent discussion allows students for whom the human perspective is of paramount importance a chance to

  1. Financial Innovation in a General Equilibrium Model

    Microsoft Academic Search

    Wolfgang Pesendorfer

    1995-01-01

    We develop a model of financial innovation, in which intermediaries can issue new financial securities against collateral in the form of standard securities. Intermediaries have to market their innovations and marketing is costly. We show that the equilibrium asset structure may exhibit redundancies as frequently observed on financial markets. We give conditions for efficiency of financial innovation and show that

  2. Equilibrium Molecular Thermodynamics from Kirkwood Sampling

    PubMed Central

    2015-01-01

    We present two methods for barrierless equilibrium sampling of molecular systems based on the recently proposed Kirkwood method (J. Chem. Phys.2009, 130, 134102). Kirkwood sampling employs low-order correlations among internal coordinates of a molecule for random (or non-Markovian) sampling of the high dimensional conformational space. This is a geometrical sampling method independent of the potential energy surface. The first method is a variant of biased Monte Carlo, where Kirkwood sampling is used for generating trial Monte Carlo moves. Using this method, equilibrium distributions corresponding to different temperatures and potential energy functions can be generated from a given set of low-order correlations. Since Kirkwood samples are generated independently, this method is ideally suited for massively parallel distributed computing. The second approach is a variant of reservoir replica exchange, where Kirkwood sampling is used to construct a reservoir of conformations, which exchanges conformations with the replicas performing equilibrium sampling corresponding to different thermodynamic states. Coupling with the Kirkwood reservoir enhances sampling by facilitating global jumps in the conformational space. The efficiency of both methods depends on the overlap of the Kirkwood distribution with the target equilibrium distribution. We present proof-of-concept results for a model nine-atom linear molecule and alanine dipeptide. PMID:25915525

  3. Social Security, Macroeconomic Risk, and General Equilibrium

    Microsoft Academic Search

    D. Peter Broer

    This paper studies the interaction between macro-economic risks, and paygo social secu- rity. For this, it uses an applied general equilibrium model with overlapping generations of risk-averse households. Important sources of risk are productivity shocks and capital return shocks. The risk profile of pensions diers from that of financial assets, because pensions are linked partially to future wage rates and

  4. Phase Equilibrium Chemistry 243 David Ronis

    E-print Network

    Ronis, David M.

    . For pure water, the triple point occurs at 0.01C and 611 Pa. Finally, note that while our simple counting if there are three phases in equilibrium, which implies that we can't pick anything at the so- called triple point

  5. Assessing Students' Conceptual Understanding of Solubility Equilibrium.

    ERIC Educational Resources Information Center

    Raviolo, Andres

    2001-01-01

    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…

  6. Adsorption and porosity: A multiple equilibrium analysis

    Microsoft Academic Search

    William Scott Kassel

    1998-01-01

    The goal of the research presented in this dissertation is to gain a fundamental understanding of adsorptive-adsorbent interactions in the hope that the information obtained may be applied to the rational design of new adsorbents tailored to specific adsorptives. A multiple equilibrium analysis model (MEA) has been developed to interpret adsorption isotherms and to show that the parameters obtained are

  7. THERMODYNAMICS OF THE WATER-FOODSTUFF EQUILIBRIUM

    Microsoft Academic Search

    R. V. Nunes; E. Rotstein

    1991-01-01

    The thermodynamic analysis of the water-foodstuff equilibrium is reviewed, showing how partial molar and integral enthalpies and entropies can be obtained and indicating how to manipulate the experimental data for this purpose. The need for accurate and precise data is stressed and one experimental approach is recommended. Experimental results of desorption of water from Granny Smith apples provide information which

  8. Calculating Shocks In Flows At Chemical Equilibrium

    NASA Technical Reports Server (NTRS)

    Eberhardt, Scott; Palmer, Grant

    1988-01-01

    Boundary conditions prove critical. Conference paper describes algorithm for calculation of shocks in hypersonic flows of gases at chemical equilibrium. Although algorithm represents intermediate stage in development of reliable, accurate computer code for two-dimensional flow, research leading up to it contributes to understanding of what is needed to complete task.

  9. Teaching Chemical Equilibrium with the Jigsaw Technique

    ERIC Educational Resources Information Center

    Doymus, Kemal

    2008-01-01

    This study investigates the effect of cooperative learning (jigsaw) versus individual learning methods on students' understanding of chemical equilibrium in a first-year general chemistry course. This study was carried out in two different classes in the department of primary science education during the 2005-2006 academic year. One of the classes…

  10. Nano-scale equilibrium crystal shapes

    Microsoft Academic Search

    M. Degawa; F. Szalma; E. D. Williams

    2005-01-01

    The finite size and interface effects on equilibrium crystal shape (ECS) have been investigated for the case of a surface free energy density including the free energy of step formation and inverse-square step–step interactions. Explicitly including the curvature of a crystallite leads to an extra boundary condition in the solution of the crystal shape, yielding a family of crystal shapes,

  11. NITRIC ACID, WATER AND TRIBUTYLPHOSPHATE EQUILIBRIUM SYSTEM

    Microsoft Academic Search

    L. Damiani; V. Fattore

    1959-01-01

    An investigation was made of the HNOâ and HâO extraction ; mechanism using TBP. From stoichiometric data and a consideration of the polar ; bonds, the following extraction formulae are postulated in organic phase: TBP - H ; deg O- HNO\\/' TBP - HNOâ, TBP - HâO- 2HNOâ. The fields of ; existence, curves, and equilibrium constants for these are

  12. Physics 112 Equilibrium in Chemical Reactions

    E-print Network

    Young, A. Peter

    Physics 112 Equilibrium in Chemical Reactions Peter Young I. FORMALISM This is a considerably that it is indeed a minimum. In this handout we discuss chemical reactions, which take place not at constant volume next give some examples of chemical reactions which we will use to illustrate the theory in what

  13. General Equilibrium Models: Improving the Microeconomics Classroom

    ERIC Educational Resources Information Center

    Nicholson, Walter; Westhoff, Frank

    2009-01-01

    General equilibrium models now play important roles in many fields of economics including tax policy, environmental regulation, international trade, and economic development. The intermediate microeconomics classroom has not kept pace with these trends, however. Microeconomics textbooks primarily focus on the insights that can be drawn from the…

  14. Payload specialists Patrick Baudry conducts equilibrium experiments

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Payload specialists Patrick Baudry participates in an experiment involving equilibrium and vertigo. He is anchored to the orbiter floor by foot restraints and is wearing a device over his eyes to measure angular head movement and up and down eye movement.

  15. Problems on Non-Equilibrium Statistical Physics

    E-print Network

    Kim, Moochan

    2011-08-08

    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...

  16. A Progression of Static Equilibrium Laboratory Exercises

    ERIC Educational Resources Information Center

    Kutzner, Mickey; Kutzner, Andrew

    2013-01-01

    Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…

  17. 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.)

  18. Recency, consistent learning, and Nash equilibrium

    PubMed Central

    Fudenberg, Drew; Levine, David K.

    2014-01-01

    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

  19. Recency, consistent learning, and Nash equilibrium.

    PubMed

    Fudenberg, Drew; Levine, David K

    2014-07-22

    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

  20. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands.

    PubMed

    Valente, Luis M; Phillimore, Albert B; Etienne, Rampal S

    2015-08-01

    Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. PMID:26105791

  1. A Novel Function for Arabidopsis CYCLASE1 in Programmed Cell Death Revealed by Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Analysis of Extracellular Matrix Proteins*

    PubMed Central

    Smith, Sarah J.; Kroon, Johan T. M.; Simon, William J.; Slabas, Antoni R.; Chivasa, Stephen

    2015-01-01

    Programmed cell death is essential for plant development and stress adaptation. A detailed understanding of the signal transduction pathways that regulate plant programmed cell death requires identification of the underpinning protein networks. Here, we have used a protagonist and antagonist of programmed cell death triggered by fumonisin B1 as probes to identify key cell death regulatory proteins in Arabidopsis. Our hypothesis was that changes in the abundance of cell death-regulatory proteins induced by the protagonist should be blocked or attenuated by concurrent treatment with the antagonist. We focused on proteins present in the mobile phase of the extracellular matrix on the basis that they are important for cell–cell communications during growth and stress-adaptive responses. Salicylic acid, a plant hormone that promotes programmed cell death, and exogenous ATP, which can block fumonisin B1-induced cell death, were used to treat Arabidopsis cell suspension cultures prior to isobaric-tagged relative and absolute quantitation analysis of secreted proteins. A total of 33 proteins, whose response to salicylic acid was suppressed by ATP, were identified as putative cell death-regulatory proteins. Among these was CYCLASE1, which was selected for further analysis using reverse genetics. Plants in which CYCLASE1 gene expression was knocked out by insertion of a transfer-DNA sequence manifested dramatically increased cell death when exposed to fumonisin B1 or a bacterial pathogen that triggers the defensive hypersensitive cell death. Although pathogen inoculation altered CYCLASE1 gene expression, multiplication of bacterial pathogens was indistinguishable between wild type and CYCLASE1 knockout plants. However, remarkably severe chlorosis symptoms developed on gene knockout plants in response to inoculation with either a virulent bacterial pathogen or a disabled mutant that is incapable of causing disease in wild type plants. These results show that CYCLASE1, which had no known function hitherto, is a negative regulator of cell death and regulates pathogen-induced symptom development in Arabidopsis. PMID:25862728

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

    PubMed

    Danel, J-F; Kazandjian, L

    2015-01-01

    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 C(2)H(3) 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 C(2)H(3) 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. PMID:25679719

  3. A Novel Function for Arabidopsis CYCLASE1 in Programmed Cell Death Revealed by Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) Analysis of Extracellular Matrix Proteins.

    PubMed

    Smith, Sarah J; Kroon, Johan T M; Simon, William J; Slabas, Antoni R; Chivasa, Stephen

    2015-06-01

    Programmed cell death is essential for plant development and stress adaptation. A detailed understanding of the signal transduction pathways that regulate plant programmed cell death requires identification of the underpinning protein networks. Here, we have used a protagonist and antagonist of programmed cell death triggered by fumonisin B1 as probes to identify key cell death regulatory proteins in Arabidopsis. Our hypothesis was that changes in the abundance of cell death-regulatory proteins induced by the protagonist should be blocked or attenuated by concurrent treatment with the antagonist. We focused on proteins present in the mobile phase of the extracellular matrix on the basis that they are important for cell-cell communications during growth and stress-adaptive responses. Salicylic acid, a plant hormone that promotes programmed cell death, and exogenous ATP, which can block fumonisin B1-induced cell death, were used to treat Arabidopsis cell suspension cultures prior to isobaric-tagged relative and absolute quantitation analysis of secreted proteins. A total of 33 proteins, whose response to salicylic acid was suppressed by ATP, were identified as putative cell death-regulatory proteins. Among these was CYCLASE1, which was selected for further analysis using reverse genetics. Plants in which CYCLASE1 gene expression was knocked out by insertion of a transfer-DNA sequence manifested dramatically increased cell death when exposed to fumonisin B1 or a bacterial pathogen that triggers the defensive hypersensitive cell death. Although pathogen inoculation altered CYCLASE1 gene expression, multiplication of bacterial pathogens was indistinguishable between wild type and CYCLASE1 knockout plants. However, remarkably severe chlorosis symptoms developed on gene knockout plants in response to inoculation with either a virulent bacterial pathogen or a disabled mutant that is incapable of causing disease in wild type plants. These results show that CYCLASE1, which had no known function hitherto, is a negative regulator of cell death and regulates pathogen-induced symptom development in Arabidopsis. PMID:25862728

  4. A comparison of equilibrium and non-equilibrium cycle methods for Na-cooled ATW system.

    SciTech Connect

    Kim, Y.; Hill, R. N.; Taiwo, T. A.

    2002-03-30

    An equilibrium cycle method, embodied in the REBUS-3[1] code system, has generally been used in conventional fast reactor design activities. The equilibrium cycle method provides an efficient approach for modeling reactor system, compared to the more traditional non-equilibrium cycle fuel management calculation approach. Recently, the equilibrium analysis method has been utilized for designing Accelerator Transmutation of Waste (ATW)[2,3,4] cores, in which a scattered-reloading fuel management scheme is used. Compared with the conventional fast reactors, the ATW core is significantly different in several aspects since its main mission is to incinerate the transuranic (TRU) fuels. The high burnup non-fertile fuel has large variations in composition and reactivity during its lifetime. Furthermore, a relatively short cycle length is utilized in the ATW design to limit the potentially large reactivity swing over a cycle, and consequently 7 or 8-batch fuel management is usually assumed for a high fuel burnup. The validity of the equilibrium analysis method for the ATW core, therefore, needed to be verified. The main objective of this paper is to assess the validity of the equilibrium analysis method for a Na-cooled ATW core[4], which is an alternative core design of the ATW system under development.

  5. Phase Equilibrium Investigations of Planetary Materials

    NASA Technical Reports Server (NTRS)

    Grove, T. L.

    2005-01-01

    This grant provided funds to carry out phase equilibrium studies on the processes of chemical differentiation of the moon and the meteorite parent bodies, during their early evolutionary history. Several experimental studies examined processes that led to the formation of lunar ultramafic glasses. Phase equilibrium studies were carried out on selected low-Ti and high-Ti lunar ultramafic glass compositions to provide constraints on the depth range, temperature and processes of melt generation and/or assimilation. A second set of experiments examined the role of sulfide melts in core formation processes in the earth and terrestrial planets. The major results of each paper are discussed, and copies of the papers are attached as Appendix I.

  6. Spatial distribution of thermal energy in equilibrium

    NASA Astrophysics Data System (ADS)

    Bar-Sinai, Yohai; Bouchbinder, Eran

    2015-06-01

    The equipartition theorem states that in equilibrium, thermal energy is equally distributed among uncoupled degrees of freedom that appear quadratically in the system's Hamiltonian. However, for spatially coupled degrees of freedom, such as interacting particles, one may speculate that the spatial distribution of thermal energy may differ from the value predicted by equipartition, possibly quite substantially in strongly inhomogeneous or disordered systems. Here we show that for systems undergoing simple Gaussian fluctuations around an equilibrium state, the spatial distribution is universally bounded from above by 1/2 kBT . We further show that in one-dimensional systems with short-range interactions, the thermal energy is equally partitioned even for coupled degrees of freedom in the thermodynamic limit and that in higher dimensions nontrivial spatial distributions emerge. Some implications are discussed.

  7. General equilibrium incidence of energy taxation

    SciTech Connect

    Solow, J.L.

    1984-04-01

    The pervasiveness of energy in the economy and the numerous ways in which energy taxation can distort resource allocations implies the necessity of a general equilibrium approach to the question of energy tax incidence. The author presents a general equilibrium model that accounts for domestic energy production and energy imports, direct energy consumption and use of energy as an intermediate good, and production of energy intensive and nonenergy intensive goods. He examines the incidence of three broadly-based energy taxation policies: a tax on all energy consumption, a subsidy to domestic energy production, and a tariff on energy imports. The subsidy, although not a revenue raising measure, is included because, like the other policies, it acts to reduce energy imports. Such a measure may be of interest by reducing reliance on unstable foreign sources of supply. 12 references, 3 tables.

  8. Equilibrium bed-concentration of nonuniform sediment.

    PubMed

    Sun, Zhi-Lin; Sun, Zhi-Feng; Donahue, John

    2003-01-01

    Knowledge of the equilibrium bed-concentration is vital to mathematical modeling of the river-bed deformation associated with suspended load but previous investigations only dealt with the reference concentration of uniform sediment because of difficulties in observation of the bed-concentration. This work is a first attempt to develop a theoretical formula for the equilibrium bed-concentration of any fraction of nonuniform sediment defined at the bed-surface. The formula is based on a stochastic-mechanistic model for the exchange of nonuniform sediment near the bed, and described as a function of incipient motion probability, non-ceasing probability, pick-up probability, and the ratio of the average single-step continuous motion time to static time. Comparison of bed-concentration calculated from the proposed formula with the measured data showed satisfactory agreement, indicating the present formula can be used for solving the differential equation governing the motion of suspended load. PMID:12659233

  9. FDI and Labor Markets in General Equilibrium

    Microsoft Academic Search

    Sebastián Claro

    2005-01-01

    International wage differences -driven by international technology or factor endowment differences-encourage the flow of Foreign Direct Investment from high- to low-wage countries. However, the access of high-technology firms may drive domestic wages up, dampening the incentives for FDI flows. A general equilibrium model that emphasizes the joint determination of FDI flows and labor market outcomes yield several conclusions. First, an

  10. The equilibrium boundary between grahite and diamond

    Microsoft Academic Search

    C. Scott Kennedy; George C. Kennedy

    1976-01-01

    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

  11. The Physics Classroom: Equilibrium and Statics

    NSDL National Science Digital Library

    Henderson, Tom

    This website, by Tom Henderson of Glenbrook South High School, offers a lesson explaining statics and equilibrium. It is the third in a unit on Forces in Two Dimensions and the previous lessons can be found on the left hand side of the page. Graphs, figures, and images are dispersed throughout the lesson to facilitate comprehension along with a quiz at the end to assess student understanding.

  12. Transport network equilibrium and regional deconcentration

    Microsoft Academic Search

    M Wegener

    1986-01-01

    Processes of urban and regional change can be classified in terms of their temporal characteristics as fast-adjusting, medium-response, or inert. Based on this classification, a modelling approach is presented that combines (1) a fast-adjusting equilibrium-type transport model, (2) a medium-response residential occupation (housing-market) model, and (3) a strongly lagged residential location (housing-construction) model. It is suggested that such a model

  13. Confinement-Induced Colloidal Attractions in Equilibrium

    Microsoft Academic Search

    Yilong Han; David G. Grier

    2003-01-01

    The Poisson-Boltzmann theory for colloidal electrostatic interactions predicts that charged colloidal spheres dispersed in water should repel each other, even when confined by charged surfaces. Direct measurements on highly charged polystyrene spheres, however, reveal strong, long-ranged confinement-induced attractions that have yet to be explained. We demonstrate that anomalous attractions also characterize the equilibrium pair potential for more weakly charged colloidal

  14. A Chemical Equilibrium Model for Natural Waters

    Microsoft Academic Search

    Frank J. Millero; Denis Pierrot

    1998-01-01

    This paper reviews the present status of the Pitzer chemical equilibrium model, which can be used to characterize the one-atmosphere activity coefficients of ionic and non-ionic solutes in natural waters as a function of temperature and ionic strength. The model considers the ionic interactions of the major seasalt ions (H, Na, K, Mg, Ca, Sr, Cl, Br, OH, HCO3, B(OH)4,

  15. Bifurcated helical core equilibrium states in tokamaks

    NASA Astrophysics Data System (ADS)

    Cooper, W. A.; Chapman, I. T.; Schmitz, O.; Turnbull, A. D.; Tobias, B. J.; Lazarus, E. A.; Turco, F.; Lanctot, M. J.; Evans, T. E.; Graves, J. P.; Brunetti, D.; Pfefferlé, D.; Reimerdes, H.; Sauter, O.; Halpern, F. D.; Tran, T. M.; Coda, S.; Duval, B. P.; Labit, B.; Pochelon, A.; Turnyanskiy, M. R.; Lao, L.; Luce, T. C.; Buttery, R.; Ferron, J. R.; Hollmann, E. M.; Petty, C. C.; van Zeeland, M.; Fenstermacher, M. E.; Hanson, J. M.; Lütjens, H.

    2013-07-01

    Tokamaks with weak to moderate reversed central shear in which the minimum inverse rotational transform (safety factor) qmin is in the neighbourhood of unity can trigger bifurcated magnetohydrodynamic equilibrium states, one of which is similar to a saturated ideal internal kink mode. Peaked prescribed pressure profiles reproduce the ‘snake’ structures observed in many tokamaks which has led to a novel explanation of the snake as a bifurcated equilibrium state. Snake equilibrium structures are computed in simulations of the tokamak à configuration variable (TCV), DIII-D and mega amp spherical torus (MAST) tokamaks. The internal helical deformations only weakly modulate the plasma-vacuum interface which is more sensitive to ripple and resonant magnetic perturbations. On the other hand, the external perturbations do not alter the helical core deformation in a significant manner. The confinement of fast particles in MAST simulations deteriorate with the amplitude of the helical core distortion. These three-dimensional bifurcated solutions constitute a paradigm shift that motivates the applications of tools developed for stellarator research in tokamak physics investigations.

  16. The accurate determination of molecular equilibrium structures

    NASA Astrophysics Data System (ADS)

    Bak, Keld L.; Gauss, Jürgen; Jørgensen, Poul; Olsen, Jeppe; Helgaker, Trygve; Stanton, John F.

    2001-04-01

    Equilibrium structures have been determined for 19 molecules using least-squares fits involving rotational constants from experiment and vibrational corrections from high-level electronic-structure calculations. Equilibrium structures obtained by this procedure have a uniformly high quality. Indeed, the accuracy of the results reported here likely surpasses that reported in most experimental determinations. In addition, the accuracy of equilibrium structures obtained by energy minimization has been calibrated for the following standard models of ab initio theory: Hartree-Fock, MP2, CCSD, and CCSD(T). In accordance with previous observations, CCSD(T) is significantly more accurate than the other models; the mean and maximum absolute errors for bond distances of the 19 molecules are 0.09 and 0.59 pm, respectively, in CCSD(T)/cc-pCVQZ calculations. The maximum error is obtained for ROO in H2O2 and is so large compared with the mean absolute error that an experimental reinvestigation of this molecule is warranted.

  17. Hamiltonian approach to the magnetostatic equilibrium problem

    SciTech Connect

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

    1995-02-01

    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.

  18. Equilibrium Gold Nanoclusters Quenched with Biodegradable Polymers

    PubMed Central

    Murthy, Avinash K.; Stover, Robert J.; Borwankar, Ameya U.; Nie, Golay D.; Gourisankar, Sai; Truskett, Thomas M.; Sokolov, Konstantin V.; Johnston, Keith P.

    2013-01-01

    Although sub-100 nm nanoclusters of metal nanoparticles are of interest in many fields including biomedical imaging, sensors and catalysis, it has been challenging to control their morphologies and chemical properties. Herein, a new concept is presented to assemble equilibrium Au nanoclusters of controlled size by tuning the colloidal interactions with a polymeric stabilizer, PLA(1k)-b-PEG(10k)-b-PLA(1k). The nanoclusters form upon mixing a dispersion of ~5 nm Au nanospheres with a polymer solution followed by partial solvent evaporation. A weakly adsorbed polymer quenches the equilibrium nanocluster size and provides steric stabilization. Nanocluster size is tuned from ~20 nm to ~40 nm by experimentally varying the final Au nanoparticle concentration and the polymer/Au ratio, along with the charge on the initial Au nanoparticle surface. Upon biodegradation of the quencher, the nanoclusters reversibly and fully dissociate to individual ~5 nm primary particles. Equilibrium cluster size is predicted semi-quantitatively with a free energy model that balances short-ranged depletion and van der Waals attractions with longer-ranged electrostatic repulsion, as a function of the Au and polymer concentrations. The close spacings of the Au nanoparticles in the clusters produce strong NIR extinction over a broad range of wavelengths from 650 to 900 nm, which is of practical interest in biomedical imaging. PMID:23230905

  19. Thermodynamics and Kinetics of Chemical Equilibrium in Solution.

    ERIC Educational Resources Information Center

    Leenson, I. A.

    1986-01-01

    Discusses theory of thermodynamics of the equilibrium in solution and dissociation-dimerization kinetics. Describes experimental procedure including determination of molar absorptivity and equilibrium constant, reaction enthalpy, and kinetics of the dissociation-dimerization reaction. (JM)

  20. On the Equilibrium States of Interconnected Bubbles or Balloons.

    ERIC Educational Resources Information Center

    Weinhaus, F.; Barker, W.

    1978-01-01

    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)

  1. CONVERGENCE TO EQUILIBRIUM FOR THE CONTINUOUS COAGULATION-FRAGMENTATION EQUATION

    E-print Network

    Mischler, Stéphane

    CONVERGENCE TO EQUILIBRIUM FOR THE CONTINUOUS COAGULATION-FRAGMENTATION EQUATION Philippe Lauren coagulation-fragmentation equa- tion under the detailed balance condition. We deduce the convergence time convergence to an equilibrium state for solutions to the continuous coagulation

  2. On the Concept "Chemical Equilibrium": The Associative Framework.

    ERIC Educational Resources Information Center

    Gussarsky, Esther; Gorodetsky, Malka

    1990-01-01

    Word associations were used to map high school students' concepts of "chemical equilibrium" and "equilibrium." It was found that the preconception of the two concepts was differentiated on noncritical dimensions. (Author/CW)

  3. Efficient Learning Equilibrium Ronen I. Brafman Moshe Tennenholtz

    E-print Network

    Chen, Yiling

    Efficient Learning Equilibrium Ronen I. Brafman Moshe Tennenholtz Computer Science Department, machine learning, artificial intelligence, and related fields for quite some time [18, 7]. Much behavior, as prescribed by a Nash equilibrium. The learning algorithms themselves are not required

  4. General equilibrium and fixed point theory: A partial survey

    Microsoft Academic Search

    Hichem Ben-El-Mechaiekh; Philippe Bich; Monique Florenzano

    2009-01-01

    .  Focusing mainly on equilibrium existence results, this paper emphasizes the role of fixed point theorems in the development\\u000a of general equilibrium theory, for its standard definition as well as for some of its extensions.

  5. Constant Flux Relation in Non-equilibrium Statistical Mechanics

    E-print Network

    Fominov, Yakov

    Constant Flux Relation in Non-equilibrium Statistical Mechanics Oleg Zaboronski Department at the sink. Constant flux of I through the inertial range. Non-equilibrium stationary state. Lack of detailed at the sink. Constant flux of I through the inertial range. Non-equilibrium stationary state. Lack of detailed

  6. Equilibrium Models in Real Estate Research: A Survey

    Microsoft Academic Search

    PATRIC H. HENDERSHOTT

    1998-01-01

    Equilibrium analysis is a valuable tool in real estate investment research. In this survey, I show how equilibrium models have been used to estimate the required risk premium for different classes of real estate, to explain real house prices, and to determine investment rental market adjustment and valuation (as well as to predict future rent, price, and value developments). Equilibrium

  7. THE EQUILIBRIUM FINITE ELEMENTS IN COMPUTATION OF ELASTIC STRUCTURES

    Microsoft Academic Search

    S. Kalanta

    1995-01-01

    A problem of elastic structures stress-strain field determination is considered in this article. A theoretical background and computation algorithms of equilibrium finite element method are presented there. The different external effects are estimated, namely: load, prestressing, inicial strains and support settlements. The dual relationships (equilibrium and geometrical equations, stiffness and flexibility equations) of equilibrium element, also the expressions of stiffness

  8. Computable General Equilibrium Models for the Analysis of

    E-print Network

    Wing, Ian Sue

    Computable General Equilibrium Models for the Analysis of Economy-Environment Interactions Ian Sue is an introduction to the subject of computable general equilibrium (CGE) modeling in environmental and resource. Phone: (617) 353-5741. Email: isw@bu.edu. 1 #12;Walrasian general equilibrium prevails when supply

  9. ccsd00000258 A far-from-equilibrium uctuation-dissipation

    E-print Network

    , 75.10.Hk #12; Fluctuation-dissipation relation for an Ising-Glauber-like model 2 1. Introduction equilibrium. In particular, the uctuation-dissipation theorem (FDT) which holds at equilibrium is knownccsd­00000258 (version 2) : 21 Jul 2003 A far-from-equilibrium uctuation-dissipation relation

  10. Upwind residual distribution schemes for chemical non-equilibrium flows

    E-print Network

    van der Weide, Edwin

    Upwind residual distribution schemes for chemical non-equilibrium flows G. Degrez , E. van der of thermally perfect gases in chemical non-equilibrium. First, a multi-dimensional conservative linearization. In contrast, when the flow is in chemical non-equilibrium, a sepa- rate mass conservation law has

  11. GLOBAL OPTIMIZATION FOR THE PHASE AND CHEMICAL EQUILIBRIUM PROBLEM

    E-print Network

    Neumaier, Arnold

    GLOBAL OPTIMIZATION FOR THE PHASE AND CHEMICAL EQUILIBRIUM PROBLEM: APPLICATION TO THE NRTL of solutions to the phase and chemical equilibrium problem when the problem is posed as the minimization the equilibrium condition. For many chemical engineering applications this function will be the Gibbs free energy

  12. Eulerian and Lagrangian pictures of non-equilibrium diffusions

    E-print Network

    Raphael Chetrite; Krzysztof Gawedzki

    2009-05-28

    We show that a non-equilibrium diffusive dynamics in a finite-dimensional space takes in the Lagrangian frame of its mean local velocity an equilibrium form with the detailed balance property. This explains the equilibrium nature of the fluctuation-dissipation relations in that frame observed previously. The general considerations are illustrated on few examples of stochastic particle dynamics.

  13. Towards breaking temperature equilibrium in multi-component Eulerian schemes

    SciTech Connect

    Grove, John W [Los Alamos National Laboratory; Masser, Thomas [Los Alamos National Laboratory

    2009-01-01

    We investigate the effects ofthermal equilibrium on hydrodynamic flows and describe models for breaking the assumption ofa single temperature for a mixture of components in a cell. A computational study comparing pressure-temperature equilibrium simulations of two dimensional implosions with explicit front tracking is described as well as implementation and J-D calculations for non-equilibrium temperature methods.

  14. Effects of phlorizin on diabetic retinopathy according to isobaric tags for relative and absolute quantification–based proteomics in db/db mice

    PubMed Central

    Zhang, Shi-yang; Li, Bao-ying; Li, Xiao-li; Cheng, Mei; Cai, Qian; Yu, Fei; Wang, Wei-dong; Tan, Min; Yan, Guang; Hu, Shi-lian

    2013-01-01

    Purpose Diabetic retinopathy (DR) is a leading cause of vision loss in working-age people. To retard the development and progression of retina lesions, effective therapeutic strategies directed toward key molecular targets are desired. Phlorizin is effective in treating diabetic complications, but little is known about functional protein changes that may mediate its actions. The aim of this study was to identify retinal proteomic alterations in db/db mice treated with phlorizin. Methods We used C57BLKS/J db/db mice as a type 2 diabetic animal model, while C57BLKS/J db/m mice were selected as the control. Phlorizin (20 mg/kg bodyweight /d) was administrated to db/db mice for ten weeks. Serum fasting blood glucose and advanced glycation end products were determined. Meanwhile, retina cell apoptosis was determined with terminal transferase dUTP nick end labeling. Isobaric tags for relative and absolute quantification and subsequent liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to identify and profile retinal proteins among control, untreated diabetic, and phlorizin-treated db/db mice. The expression of glial fibrillary acidic protein was measured in retinas using western blotting analysis. Results Phlorizin treatment significantly reduced fasting blood glucose and levels of advanced glycation end products (p<0.05) and remarkably inhibited retina cell apoptosis and the expression of glial fibrillary acidic protein in the retinas of db/db mice. In addition, we identified 1,636 proteins from retina tissue in total, of which 348 proteins were differentially expressed in db/db mice compared with the controls. Only 60 proteins in the retinas of the db/db mice were found to be differentially changed following phlorizin treatment, including 33 proteins that were downregulated and 27 proteins that were upregulated. Most of these differentially changed proteins were involved in oxidative stress, apoptosis, energy metabolism, and signaling transduction. Conclusions Our study revealed the expression of proteins differentially changed after phlorizin therapy. These proteins are most likely to participate in the development and recovery of DR. Our findings help expand understanding of the mechanism underlying the onset and progression of DR, and provide novel targets for evaluating the effects of phlorizin therapy. PMID:23592918

  15. Dynamics of Charged Particles in an Adiabatic Thermal Beam Equilibrium

    SciTech Connect

    Chen Chiping; Wei Haofei [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2010-11-04

    Charged-particle motion is studied in the self-electric and self-magnetic fields of a well-matched, intense charged-particle beam and an applied periodic solenoidal magnetic focusing field. The beam is assumed to be in a state of adiabatic thermal equilibrium. The phase space is analyzed and compared with that of the well-known Kapchinskij-Vladimirskij (KV)-type beam equilibrium. It is found that the widths of nonlinear resonances in the adiabatic thermal beam equilibrium are narrower than those in the KV-type beam equilibrium. Numerical evidence is presented, indicating almost complete elimination of chaotic particle motion in the adiabatic thermal beam equilibrium.

  16. Thermo-chemical dynamics and chemical quasi-equilibrium of plasmas in thermal non-equilibrium

    SciTech Connect

    Massot, Marc [Laboratoire EM2C, UPR 288 CNRS - Ecole Centrale Paris (France); Graille, Benjamin [Laboratoire de Mathematiques d'Orsay, UMR 8628 CNRS - Universite Paris-Sud (France); Magin, Thierry E. [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics (Belgium)

    2011-05-20

    We examine both processes of ionization by electron and heavy-particle impact in spatially uniform plasmas at rest in the absence of external forces. A singular perturbation analysis is used to study the following physical scenario, in which thermal relaxation becomes much slower than chemical reactions. First, electron-impact ionization is investigated. The dynamics of the system rapidly becomes close to a slow dynamics manifold that allows for defining a unique chemical quasi-equilibrium for two-temperature plasmas and proving that the second law of thermodynamics is satisfied. Then, all ionization reactions are taken into account simultaneously, leading to a surprising conclusion: the inner layer for short time scale (or time boundary layer) directly leads to thermal equilibrium. Global thermo-chemical equilibrium is reached within a short time scale, involving only chemical reactions, even if thermal relaxation through elastic collisions is assumed to be slow.

  17. Equilibrium and shot noise in mesoscopic systems

    SciTech Connect

    Martin, T.

    1994-10-01

    Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise < {Delta}{sup 2}I >= 2I{Delta}{mu} as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected.

  18. Multicomponent Equilibrium Models for Testing Geothermometry Approaches

    SciTech Connect

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

    2013-02-01

    Geothermometry is an important tool for estimating deep reservoir temperature from the geochemical composition of shallower and cooler waters. The underlying assumption of geothermometry is that the waters collected from shallow wells and seeps maintain a chemical signature that reflects equilibrium in the deeper reservoir. Many of the geothermometers used in practice are based on correlation between water temperatures and composition or using thermodynamic calculations based a subset (typically silica, cations or cation ratios) of the dissolved constituents. An alternative approach is to use complete water compositions and equilibrium geochemical modeling to calculate the degree of disequilibrium (saturation index) for large number of potential reservoir minerals as a function of temperature. We have constructed several “forward” geochemical models using The Geochemist’s Workbench to simulate the change in chemical composition of reservoir fluids as they migrate toward the surface. These models explicitly account for the formation (mass and composition) of a steam phase and equilibrium partitioning of volatile components (e.g., CO2, H2S, and H2) into the steam as a result of pressure decreases associated with upward fluid migration from depth. We use the synthetic data generated from these simulations to determine the advantages and limitations of various geothermometry and optimization approaches for estimating the likely conditions (e.g., temperature, pCO2) to which the water was exposed in the deep subsurface. We demonstrate the magnitude of errors that can result from boiling, loss of volatiles, and analytical error from sampling and instrumental analysis. The estimated reservoir temperatures for these scenarios are also compared to conventional geothermometers. These results can help improve estimation of geothermal resource temperature during exploration and early development.

  19. Pre-Equilibrium Processes in Nuclear Reactions.

    NASA Astrophysics Data System (ADS)

    Field, Gaynor Mary

    1987-09-01

    Available from UMI in association with The British Library. Requires signed TDF. The quantum mechanical statistical multistep compound emission (SMCE) theory of Feshbach, Kerman and Koonin is applied to analyse the reactions induced by 14 MeV neutrons on ^{59}Co, ^ {93}Nb and ^{209} Bi. Calculations carried out in the framework of the SMCE model formalism are found to give a fair account of both the neutron and proton emission data above the (n,2n) and (n,np) thresholds. The SMCE theory is then improved by a reformulation of the original model. The revised model is confined explicitly to a description of particle-hole bound states and includes the finite depth of the potential well. Subsequent calculations improve the pre-equilibrium emission predictions compared with the earlier model. Contributions from the multiparticle emission processes are evaluated with the Weisskopf-Ewing theory, using the SMCE results as input for the second state calculations. Considered together with the results of a statistical multistep direct emission (SMDE) calculation of the (n,n^ ') reaction on ^{59 }Co at 14 MeV, the multistep theory is seen to provide a good fit to the emission data at both the forward and backward angles. The revised model is then used to predict the variation of SMCE with excitation energy and compound-state mass number. The energy dependence is seen to reflect the changing proportions of compound nucleus and pre-equilibrium processes. From a consideration of the model formalism the mass dependence of pre-equilibrium SMCE is derived. Values for the effective interaction strength deduced from these calculations are found to be rather constant over the entire energy and mass ranges.

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

    E-print Network

    Stefan Yoshi Buhmann; Stefan Scheel

    2008-08-14

    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.

  1. Equilibrium-like behavior in far-from-equilibrium chemical reaction networks

    E-print Network

    David K. Lubensky

    2008-07-04

    In an equilibrium chemical reaction mixture, the number of molecules present obeys a Poisson distribution. We ask when the same is true of the steady state of a nonequilibrium reaction network and obtain an essentially complete answer. In particular, we show that networks with certain topological features must have a Poisson distribution, whatever the reaction rates. Such driven systems also obey an analog of the fluctuation-dissipation theorem. Our results may be relevant to biological systems and to the larger question of how equilibrium concepts might apply to nonequilibrium systems.

  2. Confinement-Induced Colloidal Attractions in Equilibrium

    NASA Astrophysics Data System (ADS)

    Han, Yilong; Grier, David G.

    2003-07-01

    The Poisson-Boltzmann theory for colloidal electrostatic interactions predicts that charged colloidal spheres dispersed in water should repel each other, even when confined by charged surfaces. Direct measurements on highly charged polystyrene spheres, however, reveal strong, long-ranged confinement-induced attractions that have yet to be explained. We demonstrate that anomalous attractions also characterize the equilibrium pair potential for more weakly charged colloidal silica spheres sedimented into a monolayer above a glass surface. This observation substantially expands the range of conditions for which mean-field theory incorrectly predicts the sign of macroions' interactions, and provides new insights into how confinement induces long-ranged like-charge attractions.

  3. Reflective equilibrium and the 'moral conservatism' objection 

    E-print Network

    Chandler, James Robert

    2002-01-01

    that help us arrive at conect answers? I will be discussing a modified version of reflective equilibrium, which is one such method. It may be helpful to position it in relation to some other moral theories. Onc such resource for justification of moral... utilitarianism judges specific actions from the standpoint of a general rule. The rules, in turn, are justified by an appeal to utility. The utilitarian standard has come under attack from several sides. One objection is that it demands too little. It turns us...

  4. Nonequilibrium and equilibrium shock front radiation measurements

    NASA Astrophysics Data System (ADS)

    Sharma, Surendra P.; Gillespie, Walter

    1990-01-01

    The intensities of the radiation emitted behind a normal shock wave in N were measured in an electric-arc driven shock tube at a shock velocity of 6.2 km/sec. Both a time-resolved broad-band radiation intensity measurement and a time-frozen spectral measurement were conducted. The rotational and vibrational temperatures are determined in both the equilibrium and the nonequilibrium regions. The results are compared with the similar data obtained by Allen et al. (1961). The measured rotational temperature seems to be in nonequilibrium, contradicting the two-temperature assumption of Park (1988), but the measured vibrational temperature agrees with Park's model.

  5. Non-equilibrium ionization in Puppis A

    NASA Technical Reports Server (NTRS)

    Winkler, P. F.; Bromley, B. C.; Canizares, C. R.

    1983-01-01

    High resolution X-ray spectroscopy of the brightest knot of emission in the Puppis A supernova remnant shows that it is made up of ionizing plasma, far from equilibrium. Flux measurements in several X-ray lines make it possible to determine the nonequilibrium conditions: electron temperature, ion populations, and time since the knot was heated by the supernova shock. Imaging and spectroscopic data from the Einstein Observatory together suggest that this knot is a cloud of density about 10 per cu cm which has recently been shocked to a temperature 7,000,000 K. Radio and optical data on the region appear consistent with this picture.

  6. Adaptive Implicit Non-Equilibrium Radiation Diffusion

    SciTech Connect

    Philip, Bobby [ORNL; Wang, Zhen [ORNL; Berrill, Mark A [ORNL; Rodriguez Rodriguez, Manuel [ORNL; Pernice, Michael [Idaho National Laboratory (INL)

    2013-01-01

    We describe methods for accurate and efficient long term time integra- tion of non-equilibrium radiation diffusion systems: implicit time integration for effi- cient long term time integration of stiff multiphysics systems, local control theory based step size control to minimize the required global number of time steps while control- ling accuracy, dynamic 3D adaptive mesh refinement (AMR) to minimize memory and computational costs, Jacobian Free Newton-Krylov methods on AMR grids for efficient nonlinear solution, and optimal multilevel preconditioner components that provide level independent solver convergence.

  7. Universality in equilibrium and away from it: A personal perspective

    SciTech Connect

    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

    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).

  8. Temperature of systems out of thermodynamic equilibrium

    NASA Astrophysics Data System (ADS)

    Garden, J.-L.; Richard, J.; Guillou, H.

    2008-07-01

    Two phenomenological approaches are currently used in the study of the vitreous state. One is based on the concept of fictive temperature introduced by Tool [J. Res. Natl. Bur. Stand. 34, 199 (1945)] and recently revisited by Nieuwenhuizen [Phys. Rev. Lett. 80, 5580 (1998)]. The other is based on the thermodynamics of irreversible processes initiated by De Donder at the beginning of the last century [L'Affinité (Gauthier-Villars, Paris, 1927)] and recently used by Möller et al. for a thorough study of the glass transition [J. Chem. Phys. 125, 094505 (2006)]. This latter approach leads to the possibility of describing the glass transition by means of the freezing-in of one or more order parameters connected to the internal structural degrees of freedom involved in the vitrification process. In this paper, the equivalence of the two preceding approaches is demonstrated, not only for glasses but in a very general way for any system undergoing an irreversible transformation. This equivalence allows the definition of an effective temperature for all systems departed from equilibrium generating a positive amount of entropy. In fact, the initial fictive temperature concept of Tool leads to the generalization of the notion of temperature for systems out of thermodynamic equilibrium, for which glasses are just particular cases.

  9. On Chemical Equilibrium in Nuclear Collisions

    E-print Network

    F. Becattini; M. Gazdzicki; J. Sollfrank

    1997-10-29

    The data on average hadron multiplicities in central A+A collisions measured at CERN SPS are analysed with the ideal hadron gas model. It is shown that the full chemical equilibrium version of the model fails to describe the experimental results. The agreement of the data with the off-equilibrium version allowing for partial strangeness saturation is significantly better. The freeze-out temperature of about 180 MeV seems to be independent of the system size (from S+S to Pb+Pb) and in agreement with that extracted in e+e-, pp and p{\\bar p} collisions. The strangeness suppression is discussed at both hadron and valence quark level. It is found that the hadronic strangeness saturation factor gamma_S increases from about 0.45 for pp interactions to about 0.7 for central A+A collisions with no significant change from S+S to Pb+Pb collisions. The quark strangeness suppression factor lambda_S is found to be about 0.2 for elementary collisions and about 0.4 for heavy ion collisions independently of collision energy and type of colliding system

  10. Equilibrium states of homogeneous sheared compressible turbulence

    NASA Astrophysics Data System (ADS)

    Riahi, M.; Lili, T.

    2011-06-01

    Equilibrium states of homogeneous compressible turbulence subjected to rapid shear is studied using rapid distortion theory (RDT). The purpose of this study is to determine the numerical solutions of unsteady linearized equations governing double correlations spectra evolution. In this work, RDT code developed by authors solves these equations for compressible homogeneous shear flows. Numerical integration of these equations is carried out using a second-order simple and accurate scheme. The two Mach numbers relevant to homogeneous shear flow are the turbulent Mach number Mt, given by the root mean square turbulent velocity fluctuations divided by the speed of sound, and the gradient Mach number Mg which is the mean shear rate times the transverse integral scale of the turbulence divided by the speed of sound. Validation of this code is performed by comparing RDT results with direct numerical simulation (DNS) of [A. Simone, G.N. Coleman, and C. Cambon, Fluid Mech. 330, 307 (1997)] and [S. Sarkar, J. Fluid Mech. 282, 163 (1995)] for various values of initial gradient Mach number Mg0. It was found that RDT is valid for small values of the non-dimensional times St (St < 3.5). It is important to note that RDT is also valid for large values of St (St > 10) in particular for large values of Mg0. This essential feature justifies the resort to RDT in order to determine equilibrium states in the compressible regime.

  11. Accurate equilibrium structures for piperidine and cyclohexane.

    PubMed

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

    2015-03-01

    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

  12. Shear viscosity and out of equilibrium dynamics

    E-print Network

    Andrej El; Zhe Xu; Carsten Greiner; Azwinndini Muronga

    2009-06-18

    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.

  13. Plutonium—an Element Never at Equilibrium

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2008-07-01

    The relentless deposition of energy from the ?-particle decay of plutonium damages its crystal lattice and transmutes plutonium into other elements over time (principally, helium, americium, uranium, and neptunium). At cryogenic temperatures (4 K), lattice damage causes significant volume expansion of pure plutonium and contraction of face-centered-cubic stabilized alloys, and both appear to lose crystallinity at long irradiation times. At room temperature, much of the lattice damage is annealed out because defects produced by self-irradiation are sufficiently mobile. Nevertheless, plutonium’s delicate balance of stability with changes in temperature, pressure, or chemistry may be affected by self-irradiation. For example, at room temperature the lattice of fcc plutonium alloys expands and exhibits nanoscale bubbles at irradiation levels <0.1 displacements per atom (dpa). In addition to self-irradiation damage, it is now generally agreed that most fcc alloys previously believed to be thermodynamically stable at room temperature are in fact metastable. They undergo eutectoidal decomposition to ?-plutonium, plus the nearest intermetallic compound. However, for most practical purposes, the kinetics of phase decomposition are too slow to be of concern. So, although plutonium may not be “far” from equilibrium, it is never at equilibrium because of the very nature of its radioactive decay. Surface reactions in plutonium can be increased catastrophically by the presence of moist air or hydrogen.

  14. Diluted Equilibrium Sterile Neutrino Dark Matter

    E-print Network

    Patwardhan, Amol V; Kishimoto, Chad T; Kusenko, Alexander

    2015-01-01

    We present a model where sterile neutrinos with rest masses in the range ~ keV to ~ MeV can be the dark matter and be consistent with all laboratory, cosmological, large scale structure, and X-ray constraints. These sterile neutrinos are assumed to freeze out of thermal and chemical equilibrium with matter and radiation in the very early universe, prior to an epoch of prodigious entropy generation ("dilution") from out-of-equilibrium decay of heavy particles. In this work, we consider heavy, entropy-producing particles in the ~ TeV to ~ EeV rest mass range, possibly associated with new physics at high energy scales. The process of dilution can give the sterile neutrinos the appropriate relic densities, but it also alters their energy spectra so that they could act like cold dark matter, despite relatively low rest masses as compared to conventional dark matter candidates. Moreover, since the model does not rely on active-sterile mixing for producing the relic density, the mixing angles can be small enough to ...

  15. Equilibrium & Nonequilibrium Fluctuation Effects in Biopolymer Networks

    NASA Astrophysics Data System (ADS)

    Kachan, Devin Michael

    Fluctuation-induced interactions are an important organizing principle in a variety of soft matter systems. In this dissertation, I explore the role of both thermal and active fluctuations within cross-linked polymer networks. The systems I study are in large part inspired by the amazing physics found within the cytoskeleton of eukaryotic cells. I first predict and verify the existence of a thermal Casimir force between cross-linkers bound to a semi-flexible polymer. The calculation is complicated by the appearance of second order derivatives in the bending Hamiltonian for such polymers, which requires a careful evaluation of the the path integral formulation of the partition function in order to arrive at the physically correct continuum limit and properly address ultraviolet divergences. I find that cross linkers interact along a filament with an attractive logarithmic potential proportional to thermal energy. The proportionality constant depends on whether and how the cross linkers constrain the relative angle between the two filaments to which they are bound. The interaction has important implications for the synthesis of biopolymer bundles within cells. I model the cross-linkers as existing in two phases: bound to the bundle and free in solution. When the cross-linkers are bound, they behave as a one-dimensional gas of particles interacting with the Casimir force, while the free phase is a simple ideal gas. Demanding equilibrium between the two phases, I find a discontinuous transition between a sparsely and a densely bound bundle. This discontinuous condensation transition induced by the long-ranged nature of the Casimir interaction allows for a similarly abrupt structural transition in semiflexible filament networks between a low cross linker density isotropic phase and a higher cross link density bundle network. This work is supported by the results of finite element Brownian dynamics simulations of semiflexible filaments and transient cross-linkers. I speculate that cells take advantage of this equilibrium effect by tuning near the transition point, where small changes in free cross-linker density will affect large structural rearrangements between free filament networks and networks of bundles. Cells are naturally found far from equilibrium, where the active influx of energy from ATP consumption controls the dynamics. Motor proteins actively generate forces within biopolymer networks, and one may ask how these differ from the random stresses characteristic of equilibrium fluctuations. Besides the trivial observation that the magnitude is independent of temperature, I find that the processive nature of the motors creates a temporally correlated, or colored, noise spectrum. I model the network with a nonlinear scalar elastic theory in the presence of active driving, and study the long distance and large scale properties of the system with renormalization group techniques. I find that there is a new critical point associated with diverging correlation time, and that the colored noise produces novel frequency dependence in the renormalized transport coefficients. Finally, I study marginally elastic solids which have vanishing shear modulus due to the presence of soft modes, modes with zero deformation cost. Although network coordination is a useful metric for determining the mechanical response of random spring networks in mechanical equilibrium, it is insufficient for describing networks under external stress. In particular, under-constrained networks which are fluid-like at zero load will dynamically stiffen at a critical strain, as observed in numerical simulations and experimentally in many biopolymer networks. Drawing upon analogies to the stress induced unjamming of emulsions, I develop a kinetic theory to explain the rigidity transition in spring and filament networks. Describing the dynamic evolution of non-affine deformation via a simple mechanistic picture, I recover the emergent nonlinear strain-stiffening behavior and compare this behavior to the yield stress flow seen in soft glassy fluids. I extend th

  16. Comparison of equilibrium and non-equilibrium distribution coefficients for the human drug carbamazepine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The distribution coefficient (KD) for the human drug carbamazepine was measured using a non-equilibrium technique. Repacked soil columns were prepared using an Airport silt loam (Typic Natrustalf) with an average organic matter content of 2.45%. Carbamazepine solutions were then leached through th...

  17. Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 1. Process Simulations

    EPA Science Inventory

    BACKGROUND: Fermentative production of butanol is limited to low concentrations, typically less than 2 wt% solvent, due to product inhibition. The result is high separation energy demand by conventional distillation approaches, despite favorable vapor-liquid equilibrium and parti...

  18. Hawking Radiation and Non-equilibrium Quantum Critical Current Noise

    E-print Network

    Julian Sonner; Andrew G. Green

    2012-08-20

    The dynamical scaling of quantum critical systems in thermal equilibrium may be inherited in the driven steady-state, leading to universal out-of-equilibrium behaviour. This attractive notion has been demonstrated in just a few cases. We demonstrate how holography - a mapping between the quantum critical system and a gravity dual - provides an illuminating perspective and new results. Non-trivial out-of-equilibrium universality is particularly apparent in current noise, which is dual to Hawking radiation in the gravitational system. We calculate this in a 2-dimensional system driven by a strong in-plane electric field and deduce a universal scaling function interpolating between previously established equilibrium and far-from-equilibrium current noise. Since this applies at all fields, out-of-equilibrium experiments no longer require very high fields for comparison with theory.

  19. Equilibrium Constant as Solution to the Open Chemical Systems

    E-print Network

    Zilbergleyt, B

    2008-01-01

    According to contemporary views, equilibrium constant is relevant only to true thermodynamic equilibria in isolated systems with one chemical reaction. The paper presents a novel formula that ties-up equilibrium constant and chemical system composition at any state, isolated or open as well. Extending the logarithmic logistic map of the Discrete Thermodynamics of Chemical Equilibria, this formula maps the system population at isolated equilibrium into the population at any open equilibrium at p,T=const, using equilibrium constant as a measure. Real chemical systems comprise multiple subsystems; given the resources are limited, joint solution to the set of such expressions, each relevant to a specific subsystem, gives equilibrium composition for each of them. This result means a fundamental break through in the open systems thermodynamics and leads to formerly unknown opportunities in the analysis of real chemical objects.

  20. Equilibrium properties of chemically reacting gases

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The equilibrium energy, enthalpy, entropy, specific heat at constant volume and constant pressure, and the equation of state of the gas are all derived for chemically reacting gas mixtures in terms of the compressibility, the mol fractions, the thermodynamic properties of the pure gas components, and the change in zero point energy due to reaction. Results are illustrated for a simple diatomic dissociation reaction and nitrogen is used as an example. Next, a gas mixture resulting from combined diatomic dissociation and atomic ionization reactions is treated and, again, nitrogen is used as an example. A short discussion is given of the additional complexities involved when precise solutions for high-temperature air are desired, including effects caused by NO produced in shuffle reactions and by other trace species formed from CO2, H2O and Ar found in normal air.

  1. Radiative equilibrium model of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Samuelson, R. E.

    1983-01-01

    The present global radiative equilibrium model for the Saturn satellite Titan is restricted to the two-stream approximation, is vertically homogeneous in its scattering properties, and is spectrally divided into one thermal and two solar channels. Between 13 and 33% of the total incident solar radiation is absorbed at the planetary surface, and the 30-60 ratio of violet to thermal IR absorption cross sections in the stratosphere leads to the large temperature inversion observed there. The spectrally integrated mass absorption coefficient at thermal wavelengths is approximately constant throughout the stratosphere, and approximately linear with pressure in the troposphere, implying the presence of a uniformly mixed aerosol in the stratosphere. There also appear to be two regions of enhanced opacity near 30 and 500 mbar.

  2. Finite Size Polyelectrolyte Bundles at Thermodynamic Equilibrium

    E-print Network

    Mehmet Sayar; Christian Holm

    2006-09-11

    We present the results of extensive computer simulations performed on solutions of monodisperse charged rod-like polyelectrolytes in the presence of trivalent counterions. To overcome energy barriers we used a combination of parallel tempering and hybrid Monte Carlo techniques. Our results show that for small values of the electrostatic interaction the solution mostly consists of dispersed single rods. The potential of mean force between the polyelectrolyte monomers yields an attractive interaction at short distances. For a range of larger values of the Bjerrum length, we find finite size polyelectrolyte bundles at thermodynamic equilibrium. Further increase of the Bjerrum length eventually leads to phase separation and precipitation. We discuss the origin of the observed thermodynamic stability of the finite size aggregates.

  3. Thermal equilibrium of two quantum Brownian particles

    SciTech Connect

    Valente, D. M.; Caldeira, A. O. [Departamento de Fisica da Materia Condensada, Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, CEP 13083-970, Campinas-SP (Brazil)

    2010-01-15

    The influence of the environment in the thermal equilibrium properties of a bipartite continuous variable quantum system is studied. The problem is treated within a system-plus-reservoir approach. The considered model reproduces the Brownian motion when the two particles are isolated and induces an effective interaction between them, depending on the choice of the spectral function of the bath. The coupling between the system and the environment guarantees the translational invariance of the system in the absence of an external potential. The entanglement between the particles is measured by the logarithmic negativity, which is shown to monotonically decrease with the increase of the temperature. A range of finite temperatures is found in which entanglement is still induced by the reservoir.

  4. Confinement-induced colloidal attractions in equilibrium.

    PubMed

    Han, Yilong; Grier, David G

    2003-07-18

    The Poisson-Boltzmann theory for colloidal electrostatic interactions predicts that charged colloidal spheres dispersed in water should repel each other, even when confined by charged surfaces. Direct measurements on highly charged polystyrene spheres, however, reveal strong, long-ranged confinement-induced attractions that have yet to be explained. We demonstrate that anomalous attractions also characterize the equilibrium pair potential for more weakly charged colloidal silica spheres sedimented into a monolayer above a glass surface. This observation substantially expands the range of conditions for which mean-field theory incorrectly predicts the sign of macroions' interactions, and provides new insights into how confinement induces long-ranged like-charge attractions. PMID:12906461

  5. Equilibrium tides in differentially rotating stars

    NASA Astrophysics Data System (ADS)

    Mathis, S.; Zahn, J.-P.

    2005-11-01

    In this work, we present new theoretical advances in the modelization of the equilibrium tide in the convective envelope of solar-type binary stars. We simplify the problem by assuming that all the spins are aligned but we take into account the two-dimensional character of the rotation law in the convection zone. Following the method of Zahn (1966) we first derive the adiabatic tide which is in phase with the perturbing potential exerted by the companion. Next, we derive the dissipative tide which is in quadrature with it, using the crude MLT eddy-viscosity to model the action of turbulence on the large scale tidal flow. Finally, we discuss the impact of those processes on the dynamical evolution of binary systems. Note that our results may be applied as well to giant planets and to exo-planets, since these possess also a convection zone.

  6. Equilibrium electron-ion bunches in plasma

    SciTech Connect

    Krasovitskii, V.B. [Rostov State Univ., Rostov-na-Donu (Russian Federation); Naguchev, O.Yu. [Space Research Institute, Moscow (Russian Federation)

    1994-12-31

    The criteria of the laminated electron-ion beam electrostatic equilibrium are found, the modulated beams with the modulation frequency lower than the Langmuir plasma frequency being treated. A self-focusing mechanism is shown to exist for both electron and ion bunches. The phenomenon also occurs in the external longitudinal magnetic field. In an external transverse magnetic field the action of the Lorenz force onto electrons and ions results in the particle escaping from the potential wells, in the edge regions of the beam cross-section. However, the polarization electric field, originating from the beam charge lamination, partially compensates the Lorenz force. This, in turn, results in the enhanced transport conditions of the layered beams trough a dense plasma as compared to the case of bunched electron beams. 4 refs., 2 figs.

  7. Generation of composite galaxies in dynamic equilibrium

    NASA Astrophysics Data System (ADS)

    Fasano, Robert; Comins, Neil

    2015-01-01

    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.

  8. Non-axisymmetric local magnetostatic equilibrium

    NASA Astrophysics Data System (ADS)

    Candy, J.; Belli, E. A.

    2015-06-01

    In this work we outline an approach to the problem of local equilibrium in non-axisymmetric configurations that adheres closely to Miller's original method for axisymmetric plasmas (Miller et al. 1998 Phys. Plasmas 5, 973). Importantly, this method is novel in that it allows not only specification of 3D shape, but also explicit specification of the shear in the 3D shape. A spectrally-accurate method for solution of the resulting nonlinear partial differential equations is also developed. We verify the correctness of the spectral method, in the axisymmetric limit, through comparisons with an independent numerical solution. Some analytic results for the two-dimensional case are given, and the connection to Boozer coordinates is clarified.

  9. Oppositely charged colloids out of equilibrium

    NASA Astrophysics Data System (ADS)

    Vissers, T.

    2010-11-01

    Colloids are particles with a size in the range of a few nanometers up to several micrometers. Similar to atomic and molecular systems, they can form gases, liquids, solids, gels and glasses. Colloids can be used as model systems because, unlike molecules, they are sufficiently large to be studied directly with light microscopy and move sufficiently slow to study their dynamics. In this thesis, we study binary systems of polymethylmethacrylate (PMMA) colloidal particles suspended in low-polar solvent mixtures. Since the ions can still partially dissociate, a surface charge builds up which causes electrostatic interactions between the colloids. By carefully tuning the conditions inside the suspension, we make two kinds of particles oppositely charged. To study our samples, we use Confocal Laser Scanning Microscopy (CLSM). The positively and negatively charged particles can be distinguished by a different fluorescent dye. Colloids constantly experience a random motion resulting from random kicks of surrounding solvent molecules. When the attractions between the oppositely charged particles are weak, the particles can attach and detach many times and explore a lot of possible configurations and the system can reach thermodynamic equilibrium. For example, colloidal ‘ionic’ crystals consisting of thousands to millions of particles can form under the right conditions. When the attractions are strong, the system can become kinetically trapped inside a gel-like state. We observe that when the interactions change again, crystals can even emerge again from this gel-like phase. By using local order parameters, we quantitatively study the crystallization of colloidal particles and identify growth defects inside the crystals. We also study the effect of gravity on the growth of ionic crystals by using a rotating stage. We find that sedimentation can completely inhibit crystal growth and plays an important role in crystallization from the gel-like state. The surface potential and charge are studied by electrophoresis. Here, the velocity of the particles is measured while they are moving in an electric field. Using our real-space CLSM setup, we find that for a single-component system, the charge on the particles decreases with increasing volume fraction. Apart from structures that oppositely charged particles form close to thermodynamic equilibrium, we also study pattern formation when the system is driven out of equilibrium by an electric field. When oppositely charged particles are driven in opposite directions, the collisions between them cause particle of the same kind to form lanes. By combining our CLSM experiments with Brownian dynamics computer simulations, we study the structure and the dynamics of the suspension on the single-particle level. We find that the number of particles in a lane increases continuously with the field strength. By studying the dynamics and fluctuations parallel and perpendicular to the electric field direction, we identify the key mechanism of lane-formation. We show that pattern formation can easily become more complicated when we introduce alternating current (AC) fields. In addition to the formation of lanes parallel to the field-axis, bands of like-charged particles can form perpendicular to it. When the particles are sufficiently mobile, the system can be remixed again by changing the frequency. When AC-fields with higher field strengths are used, we show that complex patterns, including rotating instabilities, can emerge. The results in this thesis yield fundamental insight in electrophoresis, crystallization and pattern formation when systems are driven out of equilibrium. The results on lane- and band-formation can be relevant for the design of electronic ink (e-ink), where electrically driven oppositely charged particles are used to change the image on a piece of electronic paper.

  10. Marsh Equilibrium Theory: A Paleo Perspective

    NASA Astrophysics Data System (ADS)

    Morris, J. T.; Kemp, A.; Barber, D. C.; Culver, S. J.; Kegel, J.; Horton, B.

    2014-12-01

    Salt marshes adapt to changes in sea level by means of biogeomorphological feedback. These feedbacks maintain a dynamic equilibrium with sea level, within limits. Reconstructions of sea-level changes derived from salt?marsh sediment provide a paleo perspective for evaluating these feedbacks and for predicting the ecological effects of future sea-level rise. The Marsh Equilibrium Model (MEM) was modified to accommodate long records of sea level and sediment physical and chemical variables derived from high resolution (decadal and decimeter) reconstruction of sea level spanning the late Holocene using foraminifera preserved in North Carolina salt-marsh sediments. Model outputs from a run of nearly 1100-yr show periods of time when the marsh was predicted to be positioned near the top of the tidal frame (inundation time near zero) and times when the marsh was much deeper in the intertidal zone (inundation time of ca. 0.4). An elevation at mean sea level would correspond to an inundation time of 0.5, which is close to the lower limit of the vegetation and is indicative of a marsh that is just forming or, alternatively, a marsh that is on the verge of collapse. The model also indicates that the standing biomass on the marsh surface and sediment organic matter (SOM) content would have varied in harmony with the inundation time. In times past when the inundation time and the opportunity for mineral sedimentation decreased, the sediment organic matter (SOM) content increased. The low SOM concentration near the marsh surface today is consistent with a marsh that is low in the tidal frame. The SOM depth profile is a function of the relative elevation of the marsh, as well as changes in the input of inorganic sediment to the estuary. To effectively manage and preserve valuable salt-marsh ecosystems it is critical to accurately predict their response to projected sea-level changes.

  11. Radiation temperature of non-equilibrium plasmas

    SciTech Connect

    Arunasalam, V.

    1991-07-01

    In fusion devices measurements of the radiation temperature T{sub r} ({omega}, k) near the electron cyclotron frequency {omega}{sub C} and the second harmonic 2{omega}{sub C} in directions nearly perpendicular to the confining magnetic field B (i.e., k {approx} k {perpendicular}) serve to map out the electron temperature profiles T{sub e}(r,t). For optically thick plasma at thermodynamic equilibrium T{sub r} = T{sub e}. However, there is increasing experimental evidence for the presence of non-equilibrium electron distributions (such as a drifting Maxwellian with appreciable values of the streaming parameter {omicron} = v{sub d}/v{sub t}, a bi- Maxwellian, and anisotropic Maxwellian with T {perpendicular} {ne} T {parallel}, etc.,) in tokamak plasmas, especially in the presence of radio-frequency heating. Here, we examine (both non-relativistically and relativistically) the dependence of T{sub r} on {omicron}, T{perpendicular}/T{parallel}, T{sub h}/T{sub b}, n{sub h}/n{sub b}etc., where n{sub b}, n{sub h}, T{sub b}, T{sub h} are the densities and temperatures, respectively, of the bulk and the hot components of the bi-Maxwellian plasma. Our bi-Maxwellian results predict that the ratio T{sub r}/T{sub e} is a very sensitive function of the ratios n{sub h}/n{sub b} and T{sub h}/T{sub b}. Further, these relativistic and non-relativistic results satisfy the well-known limit c {yields} {infinity} correspondence principle'', showing that the intensity of the emission and absorption line is independent of the line broadening mechanism. 44 refs., 2 figs.

  12. Non-equilibrium solidification in austenitic stainless steel welds

    Microsoft Academic Search

    J. M. Vitek; S. A. David

    1991-01-01

    Recent studies have shown that non-equilibrium solidification may occur in a wide range of stainless steel alloy compositions. The non-equilibrium microstructures that are found are commonly produced in laser and electron beam-welded materials but they can also be observed, in some cases, in welds produced by conventional arc welding. In general, non-equilibrium solidification extends the range of compositions in which

  13. The equilibrium figures of Phobos and other small bodies

    NASA Technical Reports Server (NTRS)

    Soter, S.; Harris, A.

    1977-01-01

    Computations of figures of hydrostatic equilibrium for isolated rotating bodies are discussed. It is shown that the theoretical figure of equilibrium for Phobos is a triaxial ellipsoid whose a and b axes differ by about 25% and that this difference is less than 2% for Deimos. A density of less than 3.9 g/cu cm is estimated for Phobos. Equilibrium figures are also examined for the inner satellites of Jupiter and Saturn as well as for small asteroids.

  14. Teaching Chemical Equilibrium and Thermodynamics in Undergraduate General Chemistry Classes.

    ERIC Educational Resources Information Center

    Banerjee, Anil C.

    1995-01-01

    Discusses some of the conceptual difficulties encountered by undergraduate students in learning certain aspects of chemical equilibrium and thermodynamics. Discusses teaching strategies for dealing with these difficulties. (JRH)

  15. Dilatonic Equation of Hydrostatic Equilibrium and Neutron Star Structure

    E-print Network

    S. H. Hendi; G. H. Bordbar; B. Eslam Panah; M. Najafi

    2015-06-30

    In this paper, we present a new hydrostatic equilibrium equation related to dilaton gravity. We consider a spherical symmetric metric to obtain the hydrostatic equilibrium equation of stars in $4$-dimensions, and generalize TOV equation to the case of regarding a dilaton field. Then, we calculate the structure properties of neutron star using our obtained hydrostatic equilibrium equation employing the modern equations of state of neutron star matter derived from microscopic calculations. We show that the maximum mass of neutron star depends on the parameters of dilaton field and cosmological constant. In other words, by setting the parameters of new hydrostatic equilibrium equation, we calculate the maximum mass of neutron star.

  16. Thermal instability of an expanding dusty plasma with equilibrium cooling

    SciTech Connect

    Bora, Madhurjya P.; Buzar Baruah, Manasi [Department of Physics, Gauhati University, Guwahati 781014 (India)

    2008-06-15

    An analysis of radiation induced instabilities in an expanding plasma with considerable presence of dust particles and equilibrium cooling is presented. It is shown that the equilibrium expansion and cooling destabilize the radiation condensation modes and the presence of dust particles enhances this effect. The results obtained are examined in the context of ionized, dusty-plasma environment such as that of a planetary nebula. It is shown that due to nonstatic equilibrium and finite equilibrium cooling, small-scale localized structures formed as a result of thermal instability, become transient, which agrees with the observational results. The dust-charge fluctuation is found to heavily suppress these instabilities.

  17. Calculation of individual isotope equilibrium constants for geochemical reactions

    USGS Publications Warehouse

    Thorstenson, D.C.; Parkhurst, D.L.

    2004-01-01

    Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562-581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by ?? = (Kex)1/n, where n is the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example 13C16O18O and 1H2H18O. The equilibrium constants of the isotope exchange reactions can be expressed as ratios of individual isotope equilibrium constants for geochemical reactions. Knowledge of the equilibrium constant for the dominant isotopic species can then be used to calculate the individual isotope equilibrium constants. Individual isotope equilibrium constants are calculated for the reaction CO2g = CO2aq for all species that can be formed from 12C, 13C, 16O, and 18O; for the reaction between 12C18 O2aq and 1H218Ol; and among the various 1H, 2H, 16O, and 18O species of H2O. This is a subset of a larger number of equilibrium constants calculated elsewhere (Thorstenson D. C. and Parkhurst D. L. [2002] Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigation Report 02-4172. U.S. Geological Survey). Activity coefficients, activity-concentration conventions for the isotopic variants of H2O in the solvent 1H216Ol, and salt effects on isotope fractionation have been included in the derivations. The effects of nonideality are small because of the chemical similarity of different isotopic species of the same molecule or ion. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation factors. The derivations can be extended to calculation of individual isotope equilibrium constants for ion pairs and equilibrium constants for isotopic species of other chemical elements. The individual isotope approach calculates the same phase isotopic compositions as existing methods, but also provides concentrations of individual species, which are needed in calculations of mass-dependent effects in transport processes. The equilibrium constants derived in this paper are used to calculate the example of gas-water equilibrium for CO2 in an acidic aqueous solution. ?? 2004 Elsevier Ltd.

  18. Non equilibrium electronic transport in multilayered nanostructures

    NASA Astrophysics Data System (ADS)

    Cruz-Rojas, Jesus

    Recent advances in strongly correlated materials have produced systems with novel and interesting properties like high Tc superconductors, Mott insulators and others. These novel properties have sparked an interest in industry as well as in academia as new devices are being developed. One such kind of device that can be fabricated is a heterostructure, in which layers of different compounds are stacked in a single direction. Modern deposition techniques like electron beam epitaxy, in which atomic layers of different materials are deposited one at a time creating the device, are capable of fabricating heterostructures with atomic precision. We propose a technique to study heterostructures composed of strongly correlated materials out of equilibrium. By using the Keldysh Green's function formalism in the dynamical mean field theory (DMFT) framework the properties of a multilayered device are analyzed. The system is composed of infinite dimensional 2D lattices, stacked in the z direction. The first and last planes are then connected to a bulk reservoir, and several metallic planes are used to connect the bulk reservoir to the barrier region. The barrier region is the system of interest, also known as the device. The device is composed of a number of planes where the system correlations have been turned on. The correlations are then model by using the Falicov-Kimball Hamiltonian. The device is then connected to the bulk once again from the opposite side using metallic planes creating a symmetric system. In order to study the non equilibrium properties of the device a linear vector potential A(t) = A0 + tE is turned on a long time in the past for a unit of time and then turned off. This in turn will create a current in the bulk, in effect current biasing the device, as opposed to a voltage bias in which opposite sides of the device are held to a different potential. In this document we will explain the importance of the subject, we will derive and develop the algorithm and we will discuss results and challenges obtained from performing the numerical calculations.

  19. Stable isotope (C, Cl, and H) fractionation during vaporization of trichloroethylene

    SciTech Connect

    Poulson, S.R.; Drever, J.I.

    1999-10-15

    Stable isotope fractionation during vaporization of trichloroethylene has been measured, with possible application as a technique to investigate subsurface behavior. The equilibrium value of {Delta}{sup 13}C{sub vapor-liquid} has been measured between 5 and 35 C, and {Delta}{sup 13}C{sub vapor-liquid}, {Delta}{sup 37}Cl{sub vapor-liquid}, and {Delta}D{sub vapor-liquid} have been measured during progressive evaporation of liquid trichloroethylene at 22 {+-} 2 C. Equilibrium values of {Delta}{sup 13}C{sub vapor-liquid} show a total range of 0.07--0.82{per{underscore}thousand}, with a trend of decreasing {Delta}{sup 13}C{sub vapor-liquid} with increasing temperature, from approximately +0.7{per{underscore}thousand} at 5--15 C to approximately +0.1{per{underscore}thousand} at 35 C. Progressive evaporation experiments yield values of {Delta}{sup 13}C{sub vapor-liquid} = +0.35{per{underscore}thousand} and +0.24{per{underscore}thousand}, {Delta}{sup 37}Cl{sub vapor-liquid} = {minus}1.64{per{underscore}thousand}, and {Delta}D{sub vapor-liquid} = +8.9{per{underscore}thousand}. The positive values for carbon and hydrogen isotope fractionation, while unexpected, are consistent with available quantitative and qualitative data for trichloroethylene and other contaminant hydrocarbons, but a satisfactory explanation for these observations, particularly in combination with the negative value for chlorine, remains elusive, Vapor-liquid fractionation factors have application to the investigation of the behavior of trichloroethylene at contaminated sites, particularly sites undergoing remediation by techniques such as soil vapor extraction and soil bioventing.

  20. A Better Way of Dealing with Chemical Equilibrium.

    ERIC Educational Resources Information Center

    Tykodi, Ralph J.

    1986-01-01

    Discusses how to address the concept of chemical equilibrium through the use of thermodynamic activities. Describes the advantages of setting up an equilibrium constant in terms of activities and demonstrates how to approximate those activities by practical measures such as partial pressures, mole fractions, and molar concentrations. (TW)