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1

Adaptive Implicit Non-Equilibrium Radiation Diffusion  

SciTech Connect

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.

Philip, Bobby [ORNL; Wang, Zhen [ORNL; Berrill, Mark A [ORNL; Rodriguez Rodriguez, Manuel [ORNL; Pernice, Michael [Idaho National Laboratory (INL)

2013-01-01T23:59:59.000Z

2

Electrolytes: transport properties and non-equilibrium thermodynamics  

Science Conference Proceedings (OSTI)

This paper presents a review on the application of non-equilibrium thermodynamics to transport in electrolyte solutions, and some recent experimental work and results for mutual diffusion in electrolyte solutions.

Miller, D.G.

1980-12-01T23:59:59.000Z

3

Excitation of superconducting qubits from hot non-equilibrium quasiparticles  

E-Print Network (OSTI)

Superconducting qubits probe environmental defects such as non-equilibrium quasiparticles, an important source of decoherence. We show that "hot" non-equilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-neligable increase in the qubit excited state probability P_e. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of P_e in semi-quantitative agreement with the model and rule out the typically assumed thermal distribution.

J. Wenner; Yi Yin; Erik Lucero; R. Barends; Yu Chen; B. Chiaro; J. Kelly; M. Lenander; Matteo Mariantoni; A. Megrant; C. Neill; P. J. J. O'Malley; D. Sank; A. Vainsencher; H. Wang; T. C. White; A. N. Cleland; John M. Martinis

2012-09-08T23:59:59.000Z

4

Non-equilibrium dynamics of a system with Quantum Frustration  

E-Print Network (OSTI)

Using flow equations, equilibrium and non-equilibrium dynamics of a two-level system are investigated, which couples via non-commuting components to two independent oscillator baths. In equilibrium the two-level energy splitting is protected when the TLS is coupled symmetrically to both bath. A critical asymmetry angle separates the localized from the delocalized phase. On the other hand, real-time decoherence of a non-equilibrium initial state is for a generic initial state faster for a coupling to two baths than for a single bath.

Heiner Kohler; Andreas Hackl; Stefan Kehrein

2013-04-06T23:59:59.000Z

5

Book review Title: Non-equilibrium thermodynamics for engineers  

E-Print Network (OSTI)

Book review Title: Non-equilibrium thermodynamics for engineers Authors: Signe Kjelstrup, Dick book represents a significant contribution to a better understanding of fundamental and applied non metrics" Krzysztof J. Ptasinski, member of EGY Book Review Panel 1. Review by Krzysztof J. Ptasinski

Kjelstrup, Signe

6

Stochastic Measures and Modular Evolution in Non-equilibrium Thermodynamics  

E-Print Network (OSTI)

We present an application of the theory of stochastic processes to model and categorize non-equilibrium physical phenomena. The concepts of uniformly continuous probability measures and modular evolution lead to a systematic hierarchical structure for (physical) correlation functions and non-equilibrium thermodynamical potentials. It is proposed that macroscopic evolution equations (such as dynamic correlation functions) may be obtained from a non-equilibrium thermodynamical description, by using the fact that extended thermodynamical potentials belong to a certain class of statistical systems whose probability distribution functions are defined by a stationary measure; although a measure which is, in general, different from the equilibrium Gibbs measure. These probability measures obey a certain hierarchy on its stochastic evolution towards the most probable (stationary) measure. This in turns defines a convergence sequence. We propose a formalism which considers the mesoscopic stage (typical of non-local dissipative processes such as the ones described by extended irreversible thermodynamics) as being governed by stochastic dynamics due to the effect of non-equilibrium fluctuations. Some applications of the formalism are described.

Enrique Hernandez-Lemus; Jesus K. Estrada-Gil

2009-08-15T23:59:59.000Z

7

Non-equilibrium electromagnetic fluctuations: Heat transfer and interactions  

E-Print Network (OSTI)

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in non-equilibrium cases where each body, and the environment, is at a different temperature. The formalism tracks the radiation from each body and its scatterings by the other objects. We discuss the radiation from a cylinder, emphasizing its polarized nature, and obtain the heat transfer between a sphere and a plate, demonstrating the validity of proximity transfer approximation at close separations and arbitrary temperatures.

Matthias Krger; Thorsten Emig; Mehran Kardar

2011-02-18T23:59:59.000Z

8

Ethanol reforming in non-equilibrium plasma of glow discharge  

E-Print Network (OSTI)

The results of a detailed kinetic study of the main plasma chemical processes in non-equilibrium ethanol/argon plasma are presented. It is shown that at the beginning of the discharge the molecular hydrogen is mainly generated in the reaction of ethanol H-abstraction. Later hydrogen is formed from active H, CH2OH and CH3CHOH and formaldehyde. Comparison with experimental data has shown that the used kinetic mechanism predicts well the concentrations of main species at the reactor outlet.

Levko, D

2012-01-01T23:59:59.000Z

9

Non-Equilibrium Thermodynamics formalism for Marcus cross-exchange electron transfer reaction rates  

E-Print Network (OSTI)

The cross-exchange electron transfer expression arising from Marcus theory is deduced using Onsager's non-equilibrium Thermodynamics formalism.

Sethi, Richa

2008-01-01T23:59:59.000Z

10

Non-Equilibrium 2PI Potential and Its Possible Application to Evaluation of Bulk Viscosity  

E-Print Network (OSTI)

Within non-equilibrium Green's function technique on the real-time contour and the two-particle-irreducable (2PI) $\\Phi$-functional method, a non-equilibrium potential is introduced. It naturally generalizes the conventional thermodynamic potential with which it coincides in thermal equilibrium. Variations of the non-equilibrium potential over respective parameters result in the same quantities as those of the thermodynamic potential but in arbitrary non-equilibrium. In particular, for slightly non-equilibrium inhomogeneous configurations a variation of the non-equilibrium potential over volume is associated with the trace of the non-equilibrium stress tensor. The latter is related to the bulk viscosity. This provides a novel way for evaluation of the bulk viscosity.

Ivanov, Yu B

2013-01-01T23:59:59.000Z

11

Non-Equilibrium Ionization States of GRB Environments  

E-Print Network (OSTI)

Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.

Yonetoku, D; Masai, K; Yoshida, A; Kawai, N; Namiki, M

2001-01-01T23:59:59.000Z

12

Non-Equilibrium Ionization States of GRB Environments  

E-Print Network (OSTI)

Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.

D. Yonetoku; T. Murakami; K. Masai; A. Yoshida; N. Kawai; M. Namiki

2001-07-18T23:59:59.000Z

13

Generation of hydrogen-rich gas using non equilibrium plasma discharges.  

E-Print Network (OSTI)

??This dissertation investigates Non equilibrium plasma discharges, particularly gliding arc plasma discharge and dielectric barrier discharge (DBD) as alternative techniques to thermal or catalytic conversion (more)

Odeyemi, Olufela O.

2012-01-01T23:59:59.000Z

14

Weakly nonlocal non-equilibrium thermodynamics - variational principles and Second Law  

E-Print Network (OSTI)

A general, uniform, rigorous and constructive thermodynamic approach to weakly nonlocal non-equilibrium thermodynamics is reviewed. A method is given to construct and restrict the evolution equations of physical theories according to the Second Law of thermodynamics and considering weakly nonlocal constitutive state spaces. The evolution equations of internal variables, the classical irreversible thermodynamics and Korteweg fluids are treated.

Vn, P

2009-01-01T23:59:59.000Z

15

Non-equilibrium structures: How can they be maintained? Signe Kjelstrup,  

E-Print Network (OSTI)

or by obtaining energy from the outside, of course! A non-equilibrium structure is maintained by supply of energy everywhere; in nature and in industry. Nature has evolved over billions of years, and only the fittest have in some sense. Can the understanding of natural structures be helpful for man-made designs of energy

Kjelstrup, Signe

16

Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism  

Science Conference Proceedings (OSTI)

This article reviews the application of the non-equilibrium Green's function formalism to the simulation of novel photovoltaic devices utilizing quantum confinement effects in low dimensional absorber structures. It covers well-known aspects of the fundamental ... Keywords: NEGF, Photovoltaics, Quantum dot, Quantum well

U. Aeberhard

2011-12-01T23:59:59.000Z

17

Photon production from non-equilibrium QGP in heavy ion collisions  

E-Print Network (OSTI)

We present a calculation of thermal photon production i.e. photons from secondary interactions among particles produced in heavy ion collisions at collider energies. This is done within the framework of hydrodynamics. We take into account the lack of chemical equilibrium in QGP. It turns out that main effects from chemical non-equilibrium composition of QGP, reduction of particle number and increase in temperature, nearly cancel in photon spectrum.

F. Gelis; H. Niemi; P. V. Ruuskanen; S. S. Rasanen

2004-03-15T23:59:59.000Z

18

Non-equilibrium hydrogen ionization in 2D simulations of the solar atmosphere  

E-Print Network (OSTI)

The ionization of hydrogen in the solar chromosphere and transition region does not obey LTE or instantaneous statistical equilibrium because the timescale is long compared with important hydrodynamical timescales, especially of magneto-acoustic shocks. We implement an algorithm to compute non-equilibrium hydrogen ionization and its coupling into the MHD equations within an existing radiation MHD code, and perform a two-dimensional simulation of the solar atmosphere from the convection zone to the corona. Analysis of the simulation results and comparison to a companion simulation assuming LTE shows that: a) Non-equilibrium computation delivers much smaller variations of the chromospheric hydrogen ionization than for LTE. The ionization is smaller within shocks but subsequently remains high in the cool intershock phases. As a result, the chromospheric temperature variations are much larger than for LTE because in non-equilibrium, hydrogen ionization is a less effective internal energy buffer. The actual shock temperatures are therefore higher and the intershock temperatures lower. b) The chromospheric populations of the hydrogen n = 2 level, which governs the opacity of Halpha, are coupled to the ion populations. They are set by the high temperature in shocks and subsequently remain high in the cool intershock phases. c) The temperature structure and the hydrogen level populations differ much between the chromosphere above photospheric magnetic elements and above quiet internetwork. d) The hydrogen n = 2 population and column density are persistently high in dynamic fibrils, suggesting that these obtain their visibility from being optically thick in Halpha also at low temperature.

J. Leenaarts; M. Carlsson; V. Hansteen; R. J. Rutten

2007-09-24T23:59:59.000Z

19

Space charge corrected electron emission from an aluminum surface under non-equilibrium conditions  

SciTech Connect

A theoretical study has been conducted of ultrashort pulsed laser induced electron emission from an aluminum surface. Electron emission fluxes retrieved from the commonly employed Fowler-DuBridge theory were compared to fluxes based on a laser-induced non-equilibrium electron distribution. As a result, the two- and three-photon photoelectron emission parameters for the Fowler-DuBridge theory have been approximated. We observe that at regimes where photoemission is important, laser-induced electron emission evolves in a more smooth manner than predicted by the Fowler-DuBridge theory. The importance of the actual electron distribution decreases at higher laser fluences, whereas the contribution of thermionic emission increases. Furthermore, the influence of a space charge effect on electron emission was evaluated by a one dimensional particle-in-cell model. Depending on the fluences, the space charge reduces the electron emission by several orders of magnitude. The influence of the electron emission flux profiles on the effective electron emission was found to be negligible. However, a non-equilibrium electron velocity distribution increases the effective electron emission significantly. Our results show that it is essential to consider the non-equilibrium electron distribution as well as the space charge effect for the description of laser-induced photoemission.

Wendelen, W.; Bogaerts, A. [Research Group PLASMANT, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Mueller, B. Y.; Rethfeld, B. [Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger-Strasse, 67663 Kaiserslautern (Germany); Autrique, D. [Research Group PLASMANT, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk (Belgium); Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, Erwin-Schroedinger-Strasse, 67663 Kaiserslautern (Germany)

2012-06-01T23:59:59.000Z

20

Trace formulae for non-equilibrium Casimir interactions, heat radiation and heat transfer for arbitrary objects  

E-Print Network (OSTI)

We present a detailed derivation of heat radiation, heat transfer and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal non-equilibrium. The results can be expressed as basis-independent trace formulae in terms of the scattering operators of the individual objects. We prove that heat radiation of a single object is positive, and that heat transfer (for two arbitrary passive objects) is from the hotter to a colder body. The heat transferred is also symmetric, exactly reversed if the two temperatures are exchanged. Introducing partial wave-expansions, we transform the results for radiation, transfer and forces into traces of matrices that can be evaluated in any basis, analogous to the equilibrium Casimir force. The method is illustrated by (re)deriving the heat radiation of a plate, a sphere and a cylinder. We analyze the radiation of a sphere for different materials, emphasizing that a simplification often employed for metallic nano-spheres is typically invalid. We derive asymptotic formulae for heat transfer and non-equilibrium interactions for the cases of a sphere in front a plate and for two spheres, extending previous results. As an example, we show that a hot nano-sphere can levitate above a plate with the repulsive non-equilibrium force overcoming gravity -- an effect that is not due to radiation pressure.

Matthias Krger; Giuseppe Bimonte; Thorsten Emig; Mehran Kardar

2012-07-02T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Effects of jamming on non-equilibrium transport times in nano-channels  

E-Print Network (OSTI)

Many biological channels perform highly selective transport without direct input of metabolic energy and without transitions from a 'closed' to an 'open' state during transport. Mechanisms of selectivity of such channels serve as an inspiration for creation of artificial nano-molecular sorting devices and bio-sensors. To elucidate the transport mechanisms, it is important to understand the transport on the single molecule level in the experimentally relevant regime when multiple particles are crowded in the channel. In this paper we analyze the effects of inter-particle crowding on the non-equilibrium transport times through a finite-length channel by means of analytical theory and computer simulations.

Anton Zilman; John Pearson; Golan Bel

2009-07-17T23:59:59.000Z

22

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

Science Conference Proceedings (OSTI)

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

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

2012-04-10T23:59:59.000Z

23

The Application of Dynamic Nuclear Polarization Enhanced NMR to Non-Equilibrium Systems  

E-Print Network (OSTI)

Nuclear magnetic resonance (NMR) yields remarkably detailed structural information about virtually any molecule. However, its application to non-equilibrium systems is hampered by a lack of sensitivity. To increase the amount of signal that can be obtained from a NMR experiment, various hyperpolarization schemes have been previously introduced. One such technique is dynamic nuclear polarization (DNP), which can enhance NMR sensitivity by several orders of magnitude. The work detailed here focuses on the development of methods utilizing DNP to study non-equilibrium systems such as chemical and biochemical reactions in real-time. To work with hyperpolarized samples, we have designed and constructed a rapid injection and mixing system. This system allows samples to be transported between superconducting magnets used for polarization and for NMR spectroscopy in less than two seconds. Rapid transport is essential for successful use of samples with short spin-lattice relaxation times. For the study of reactions under non-equilibrium conditions, the system provides the additional capability for samples to be mixed with a second, unpolarized reagent. A chromogenic trypsin catalyzed ester hydrolysis reaction was used to validate the DNP-NMR technique as a tool for kinetic analysis. It is shown that the DNP-NMR method agrees with the conventional UV method within the uncertainty of the measurement. Hyperpolarization in this modality presents both challenges and opportunities, each of which motivate the development of new NMR techniques. In addition to the determination of kinetics, DNP-NMR is amenable to mechanistic analysis of a reaction. We have developed a technique based on selective inversion of spin-polarization, which allows for mapping of atoms between reactant and product of a reaction. This scheme was applied to a Grignard reaction, demonstrating applicability to organic reactions. Signal averaging, as it is applied for conventional multi-dimensional correlation spectroscopy cannot always be applied easily when using hyperpolarized sample. For the rapid measurement of heteronuclear correlation spectra, we have developed a technique utilizing the differential scaling of scalar coupling under off-resonance irradiation. Although DNP-NMR yields spectra of outstanding quality even with small quantities of sample, peak intensities are not quantitative. It is nevertheless possible to compare peak multiplets obtained from fractionally isotope labeled samples. Using biosynthetically labeled lipids from E. Coli cells, we showed that the resulting labeling patterns reflect their biosynthetic pathways. As a final case-study employing several of these newly developed methods, the uronate isomerase catalyzed isomerization of glucuronate into fructuronate was studied. The ability to follow the reaction in real-time while directly observing all anomeric forms of the reactant and product permits the independent determination of kinetics for each anomeric form of substrate and product. This study revealed the anomeric specificity of the enzyme.

Bowen, Sean Michael

2011-12-01T23:59:59.000Z

24

Radiation-induced non-equilibrium redox chemistry of plutonium: implications for environmental migration  

SciTech Connect

Static concentrations of plutonium oxidation states in solution and at surfaces in oxide-water systems are identified as non-equilibrium steady states. These kinetically controlled systems are described by redox cycles based on irreversible disproportionation of Pu(IV), Pu(V), and Pu(VI) in OH-bridged intermediate complexes and at OH-covered oxide surfaces. Steady state is fixed by continuous redox cycles driven by radioactivity-promoted electron-transfer and energetically favorable reactions of Pu(III) and Pu(VII) disproportionation products with H2O. A model based on the redox cycles accounts for the high steady-state [Pu] coexisting with Pu(IV) hydrous oxide at pH 0-15 and for predominance of Pu(V) and Pu(VI) in solution. The steady-state [Pu] depends on pH and the surface area of oxide in solution, but not on the initial Pu oxidation state. PuO{sub 2+x} formation is attributed to high Pu(V) concentrations existing at water-exposed oxide surfaces. Results infer that migration of Pu in an aqueous environment is controlled by kinetic factors unique to that site and that the predominant oxidation states in solution are Pu(V) and Pu(VI).

Haschke, J M; Siekhaus, W J

2009-02-11T23:59:59.000Z

25

Unruh Effect under Non-equilibrium conditions: Oscillatory motion of an Unruh-DeWitt detector  

E-Print Network (OSTI)

The Unruh effect refers to the thermal fluctuations a detector experiences while undergoing linear motion with uniform acceleration in a Minkowski vacuum. This thermality can be demonstrated by tracing the vacuum state of the field over the modes beyond the accelerated detector's event horizon. However, the event horizon is well-defined only if the detector moves with eternal uniform linear acceleration. This idealized condition cannot be fulfilled in realistic situations when the motion unavoidably involves periods of non-uniform acceleration. Many experimental proposals to test the Unruh effect are of this nature. Often circular or oscillatory motion, which lacks an obvious geometric description, is considered in such proposals. The proper perspective for theoretically going beyond, or experimentally testing, the Unruh-Hawking effect in these more general conditions has to be offered by concepts and techniques in non-equilibrium quantum field theory. In this paper we provide a detailed analysis of how an Unruh-DeWitt detector undergoing oscillatory motion responds to the fluctuations of a quantum field. Numerical results for the late-time temperatures of the oscillating detector are presented. We comment on the digressions of these results from what one would obtain from a naive application of Unruh's result.

Jason Doukas; Shih-Yuin Lin; B. L. Hu; Robert B. Mann

2013-07-16T23:59:59.000Z

26

A comparison of equilibrium and non-equilibrium cycle methods for Na-cooled ATW system.  

SciTech Connect

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.

Kim, Y.; Hill, R. N.; Taiwo, T. A.

2002-03-30T23:59:59.000Z

27

A path integral formalism for non-equilibrium Hamiltonian statistical systems  

E-Print Network (OSTI)

In a near equilibrium statistical system the Onsager-Machlup path integral has a long and useful history. The situation far from equilibrium has remained less clear. In this contribution a new general formulation for path integrals is proposed based on mixtures of an appropriate family of quasi-equilibrium probability densities. The path integral introduced here uses a generalized Boltzmann principle to associate path likelihoods with a multiple of the information loss of a particular path with respect to Liouvillean evolution. The loss at a particular time is given by a Lagrangian function of the thermodynamical variables and their time derivatives. An important implication of the present formulation is that future thermodynamical evolution depends not just on the instantaneous thermodynamic variables but also on the particular mixture of quasi-equilibrium distributions present. This behaviour has been previously seen in direct numerical simulations of turbulent dynamical systems and is also a fundamental property of Wiener path integrals. The Lagrangian derived is formally identical to that used in quantum mechanics to describe a particle moving non-relativistically in a particular vector and scalar electromagnetic field and also within a manifold with a metric tensor equal to the Fisher information matrix of the exponential family manifold. It is shown that a simple transformation due to Roncadelli enables the derived Lagrangian to be recast into standard Onsager-Machlup form. This transformation thus enables a derivation of the thermodynamical trajectory which is the most likely path. Also revealed is a decomposition of the thermodynamical trajectory into a reversible and irreversible piece which takes the form of the non-equilibrium thermodynamical equations recently proposed by \\"Ottinger.

Richard Kleeman

2013-07-03T23:59:59.000Z

28

Contribution from the interaction Hamiltonian to the expectation value of particle number with the non-equilibrium quantum field theory  

SciTech Connect

We develop the method analyzing particle number non-conserving phenomena with non-equilibrium quantum field-theory. In this study, we consider a CP violating model with interaction Hamiltonian that breaks particle number conservation. To derive the quantum Boltzmann equation for the particle number, we solve Schwinger-Dyson equation, which are obtained from two particle irreducible closed-time-path (2PI CTP) effective action. In this calculation, we show the contribution from interaction Hamiltonian to the time evolution of expectation value of particle number.

Hotta, Ryuuichi; Morozumi, Takuya; Takata, Hiroyuki [Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Tomsk state Pedagogical University Tomsk 634041 (Russian Federation)

2012-07-27T23:59:59.000Z

29

Experimental Analysis of the Effect of Vibrational Non-Equilibrium on the Decay of Grid-Generated Turbulence  

E-Print Network (OSTI)

The technical feasibility of hypersonic flight (i.e., re-entry, hypersonic flight vehicles, cruise missiles, etc.) hinges on our ability to understand, predict, and control the transport of turbulence in the presence of non-equilibrium effects. A theoretical analysis of the governing equations suggests a mechanism by which fluctuations in internal energy are coupled to the transport of turbulence. Numerical studies of these flows have been conducted, but limited computational power results in reduced fidelity. Experimental studies are exceedingly rare and, consequently, experimental data available to build and evaluate turbulence models is nearly non-existent. The Decaying Mesh Turbulence (DMT) facility was designed and constructed to generate a fundamental decaying mesh turbulent flow field with passive grids. Vibrational non-equilibrium was achieved via a capacitively-coupled radio-frequency (RF) plasma discharge which required an operating pressure of 30 Torr. The flow velocity was 30 m/s. Data was recorded with each grid at multiple plasma powers (Off, 150 W, and 300 W). Over two terabytes of highly resolved (3,450 image pairs) two-dimensional particle image velocimetry (PIV) was acquired and archived. Temperature measurements were carried out using coherent anti-Stokes Raman spectroscopy (CARS). The primary objective of this study was to answer the fundamental scientific question: "Does thermal non-equilibrium alter the decay rate of turbulence?" The results of this study show that the answer is "Yes." The results demonstrate a clear coupling between thermal non-equilibrium and turbulence transport. The trends observed agree with those expected based on an analysis of the Reynolds stress transport equations, which provides confidence in transport equation-based modeling. A non-trivial reduction (~30%) in the decay rate downstream of the 300 W plasma discharge was observed. The data also show that the decay of TKE downstream of the plasma discharge was delayed (~20% downstream shift). In addition, the thermal non-equilbrium was observed to have no effect on the transverse stress. This suggests that, for this flow, the energy dilatation terms are small and unaffected by the plasma discharge, which simplifies modeling.

Fuller, T. J.

2009-08-01T23:59:59.000Z

30

Mott-Insulator to Liquid Transition and Population Trapping in Ultracold Fermi Gases by Non-Equilibrium Modulation of the Optical Lattice  

E-Print Network (OSTI)

An ultracold gas of interacting fermionic atoms in a three dimensional optical lattice is considered, where the lattice potential strength is periodically modulated. This non-equilibrium system is nonperturbatively described by means of a Keldysh-Floquet-Green's function approach employing a generalized dynamical mean field theory (DMFT). Strong repulsive interactions between different atoms lead to a Mott-Insulator state for the equilibrium system, but the additional external driving yields a non-equilibrium density of Floquet-states and a transition to a liquid or conducting state.

Regine Frank

2011-09-18T23:59:59.000Z

31

Non-equilibrium of Ionization and the Detection of Hot Plasma in Nanoflare-heated Coronal Loops  

E-Print Network (OSTI)

Impulsive nanoflares are expected to transiently heat the plasma confined in coronal loops to temperatures of the order of 10 MK. Such hot plasma is hardly detected in quiet and active regions, outside flares. During rapid and short heat pulses in rarified loops the plasma can be highly out of equilibrium of ionization. Here we investigate the effects of the non-equilibrium of ionization (NEI) on the detection of hot plasma in coronal loops. Time-dependent loop hydrodynamic simulations are specifically devoted to this task, including saturated thermal conduction, and coupled to the detailed solution of the equations of ionization rate for several abundant elements. In our simulations, initially cool and rarified magnetic flux tubes are heated to 10 MK by nanoflares deposited either at the footpoints or at the loop apex. We test for different pulse durations, and find that, due to NEI effects, the loop plasma may never be detected at temperatures above ~5 MK for heat pulses shorter than about 1 min. We discuss some implications in the framework of multi-stranded nanoflare-heated coronal loops.

Fabio Reale; Salvatore Orlando

2008-05-22T23:59:59.000Z

32

Transfer coefficients for the Gibbs surface in a two-phase mixture in the non-equilibrium square gradient model  

E-Print Network (OSTI)

In this paper we calculate the transfer coefficients for evaporation and condensation of mixtures. We use the continuous profiles of various thermodynamic quantities through the interface, obtained in our previous works using the square gradient model. Furthermore we introduce the Gibbs surface and obtain the excess entropy production for a surface. Following the traditional non-equilibrium thermodynamic approach we introduce the surface transfer coefficients which we are able to determine from the continuous solution. The knowledge of these coefficients is important for many industrial applications which involve transport through a surface, such as for instance distillation. In our approach the values of the local resistivities in the liquid and the vapor phases are chosen on the basis of experimental values. In the interfacial region there are small peaks in these resistivities. Three amplitudes control the magnitude of these peaks. Possible values of these amplitudes are found by matching the diagonal transfer coefficients to values predicted by kinetic theory. Using these amplitudes we find that the value of the cross resistivities is 1-2 orders of magnitude higher then the one from kinetic theory. The results of both kinetic theory and molecular dynamics simulations support the existence of small peaks in the local resistivities in the interfacial region. The square gradient approach gives an independent way to determine the transfer coefficients for surfaces. The results indicate that kinetic theory underestimates the interfacial transfer coefficients in real fluids.

K. S. Glavatskiy; D. Bedeaux

2009-07-11T23:59:59.000Z

33

Transport coefficients of n-butane into and through the surface of silicalite-1 from non-equilibrium molecular dynamics study  

E-Print Network (OSTI)

Transport coefficients of n-butane into and through the surface of silicalite-1 from non dynamics Non-equilibrium thermodynamics Silicalite-1 n-Butane adsorption a b s t r a c t We have studied coupled heat and mass transfer of n-butane through a membrane of silicalite-1. A description

Kjelstrup, Signe

34

THE ABUNDANCE OF MOLECULAR HYDROGEN AND ITS CORRELATION WITH MIDPLANE PRESSURE IN GALAXIES: NON-EQUILIBRIUM, TURBULENT, CHEMICAL MODELS  

Science Conference Proceedings (OSTI)

Observations of spiral galaxies show a strong linear correlation between the ratio of molecular to atomic hydrogen surface density R{sub mol} and midplane pressure. To explain this, we simulate three-dimensional, magnetized turbulence, including simplified treatments of non-equilibrium chemistry and the propagation of dissociating radiation, to follow the formation of H{sub 2} from cold atomic gas. The formation timescale for H{sub 2} is sufficiently long that equilibrium is not reached within the 20-30 Myr lifetimes of molecular clouds. The equilibrium balance between radiative dissociation and H{sub 2} formation on dust grains fails to predict the time-dependent molecular fractions we find. A simple, time-dependent model of H{sub 2} formation can reproduce the gross behavior, although turbulent density perturbations increase molecular fractions by a factor of few above it. In contradiction to equilibrium models, radiative dissociation of molecules plays little role in our model for diffuse radiation fields with strengths less than 10 times that of the solar neighborhood, because of the effective self-shielding of H{sub 2}. The observed correlation of R{sub mol} with pressure corresponds to a correlation with local gas density if the effective temperature in the cold neutral medium of galactic disks is roughly constant. We indeed find such a correlation of R{sub mol} with density. If we examine the value of R{sub mol} in our local models after a free-fall time at their average density, as expected for models of molecular cloud formation by large-scale gravitational instability, our models reproduce the observed correlation over more than an order-of-magnitude range in density.

Mac Low, Mordecai-Mark [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Glover, Simon C. O., E-mail: mordecai@amnh.org, E-mail: glover@uni-heidelberg.de [Zentrum der Astrophysik der Universitaet Heidelberg, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Strasse 2, 69120 Heidelberg (Germany)

2012-02-20T23:59:59.000Z

35

THE DIAGNOSTIC O VI ABSORPTION LINE IN DIFFUSE PLASMAS: COMPARISON OF NON-EQUILIBRIUM IONIZATION STRUCTURE SIMULATIONS TO FUSE DATA  

Science Conference Proceedings (OSTI)

The nature of the interstellar O VI in the Galactic disk is studied by means of a multi-fluid hydrodynamical approximation, tracing the detailed time-dependent evolution of the ionization structure of the plasma. Our focus is to explore the signature of any non-equilibrium ionization condition present in the interstellar medium using the diagnostic O VI ion. A detailed comparison between the simulations and FUSE data is carried out by taking lines of sight (LOS) measurements through the simulated Galactic disk, covering an extent of 4 kpc from different vantage points. The simulation results bear a striking resemblance with the observations: (1) the N(O VI) distribution with distance and angle fall within the minimum and maximum values of the FUSE data; (2) the column density dispersion with distance is constant for all the LOS, showing a mild decrease at large distances; (3) O VI has a clumpy distribution along the LOS; and (4) the time-averaged midplane density for distances >400 pc has a value of (1.3-1.4) Multiplication-Sign 10{sup -8} cm{sup -3}. The highest concentration of O VI by mass occurs in the thermally stable (10{sup 3.9} K < T {<=} 10{sup 4.2} K; 20%) and unstable (10{sup 4.2} K < T < 10{sup 5} K; 50%) regimes, both well below its peak temperature in collisional ionization equilibrium, with the corresponding volume filling factors oscillating with time between 8%-20% and 4%-5%, respectively. These results may also be relevant for intergalactic metal absorption systems at high redshifts.

De Avillez, Miguel A. [Department of Mathematics, University of Evora, R. Romao Ramalho 59, 7000 Evora (Portugal); Breitschwerdt, Dieter [Zentrum fuer Astronomie und Astrophysik, Technische Universitaet Berlin, Hardenbergstrasse 36, D-10623 Berlin (Germany)

2012-12-20T23:59:59.000Z

36

Potential and flux decomposition for dynamical systems and non-equilibrium thermodynamics: Curvature, gauge field, and generalized fluctuation-dissipation theorem  

SciTech Connect

The driving force of the dynamical system can be decomposed into the gradient of a potential landscape and curl flux (current). The fluctuation-dissipation theorem (FDT) is often applied to near equilibrium systems with detailed balance. The response due to a small perturbation can be expressed by a spontaneous fluctuation. For non-equilibrium systems, we derived a generalized FDT that the response function is composed of two parts: (1) a spontaneous correlation representing the relaxation which is present in the near equilibrium systems with detailed balance and (2) a correlation related to the persistence of the curl flux in steady state, which is also in part linked to a internal curvature of a gauge field. The generalized FDT is also related to the fluctuation theorem. In the equal time limit, the generalized FDT naturally leads to non-equilibrium thermodynamics where the entropy production rate can be decomposed into spontaneous relaxation driven by gradient force and house keeping contribution driven by the non-zero flux that sustains the non-equilibrium environment and breaks the detailed balance. On any particular path, the medium heat dissipation due to the non-zero curl flux is analogous to the Wilson lines of an Abelian gauge theory.

Feng Haidong [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States); Wang Jin [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States); Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States) and Department of Applied Mathematics, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States)

2011-12-21T23:59:59.000Z

37

Modelling transient heat conduction in solids at multiple length and time scales: A coupled non-equilibrium molecular dynamics/continuum approach  

SciTech Connect

A method for controlling the thermal boundary conditions of non-equilibrium molecular dynamics simulations is presented. The method is simple to implement into a conventional molecular dynamics code and independent of the atomistic model employed. It works by regulating the temperature in a thermostatted boundary region by feedback control to achieve the desired temperature at the edge of an inner region where the true atomistic dynamics are retained. This is necessary to avoid intrinsic boundary effects in non-equilibrium molecular dynamics simulations. Three thermostats are investigated: the global deterministic Nose-Hoover thermostat and two local stochastic thermostats, Langevin and stadium damping. The latter thermostat is introduced to avoid the adverse reflection of phonons that occurs at an abrupt interface. The method is then extended to allow atomistic/continuum models to be thermally coupled concurrently for the analysis of large steady state and transient heat conduction problems. The effectiveness of the algorithm is demonstrated for the example of heat flow down a three-dimensional atomistic rod of uniform cross-section subjected to a variety of boundary conditions.

Jolley, Kenny [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Gill, Simon P.A. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)], E-mail: spg3@le.ac.uk

2009-10-20T23:59:59.000Z

38

Non-Equilibrium Nanoscale Self-Organization  

SciTech Connect

Self-organized one- and two-dimensional arrays of nanoscale surface features ("ripples" and "dots") sometimes form spontaneously on initially flat surfaces eroded by a directed ion beam in a process called "sputter patterning". Experiments on this sputter patterning process with focused and unfocused ion beams, combined with theoretical advances, have been responsible for a number of scientific advances. Particularly noteworthy are (i) the discovery of propagative, rather than dissipative, behavior under some ion erosion conditions, permitting a pattern to be fabricated at a large length scale and propagated over large distances while maintaining, or even sharpening, the sharpest features; (ii) the first demonstration of guided self-organization of sputter patterns, along with the observation that defect density is minimized when the spacing between boundaries is near an integer times the natural spatial period; and (iii) the discovery of metastability of smooth surfaces, which contradicts the nearly universally accepted linear stability theory that predicts that any surface is linearly unstable to sinusoidal perturbations of some wave vector.

Aziz, Michael J

2006-03-09T23:59:59.000Z

39

Entanglement Production in Non-Equilibrium Thermodynamics  

E-Print Network (OSTI)

We define and analyse the concept of entanglement production during the evolution of a general quantum mechanical dissipative system. While it is important to minimise entropy production in order to achieve thermodynamical efficiency, maximising the rate of change of entanglement is important in quantum information processing. Quantitative relations are obtained between entropy and entanglement productions, under specific assumptions detailed in the text. We apply these to the processes of dephasing and decay of correlations between two initially entangled qubits. Both the Master equation treatment as well as the higher Hilbert space analysis are presented. Our formalism is very general and contains as special cases many reported individual instance of entanglement dynamics, such as, for example, the recently discovered notion of the sudden death of entanglement.

V. Vedral

2007-06-21T23:59:59.000Z

40

Atomic physics and non-equilibrium plasmas  

DOE Green Energy (OSTI)

Three lectures comprise the report. The lecture, Atomic Structure, is primarily theoretical and covers four topics: (1) Non-relativistic one-electron atom, (2) Relativistic one-electron atom, (3) Non-relativistic many-electron atom, and (4) Relativistic many-electron atom. The lecture, Radiative and Collisional Transitions, considers the problem of transitions between atomic states caused by interactions with radiation or other particles. The lecture, Ionization Balance: Spectral Line Shapes, discusses collisional and radiative transitions when ionization and recombination processes are included. 24 figs., 11 tabs.

Weisheit, J.C.

1986-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
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41

TENTATIVE COURSE OUTLINE PY542: NON-EQUILIBRIUM STATISTICAL PHYSICS  

E-Print Network (OSTI)

-infinite systems ­Smoluchowski theory of chemical kinetics (e) First Passage in Confined Geometries ­survival) 1) Elementary Kinetic Theory (1.5 lectures) (a) The Maxwell-Boltzmann Distribution (b) Molecular (c) The Detailed Balance Condition and Applications (d) The Ising-Glauber Model ­exact solution

Redner, Sidney

42

Focused Ion Beam Fabricated Non-equilibrium Superconducting Devices  

E-Print Network (OSTI)

high-density SNS junction arrays, dc-SQUIDs, and related devices. A simple model is devised to explain the normal-state resistance and critical current of a junction. The model is based on the geometry of a junction as defined by the FIB instrument... and phonon energy distributions....................... 37 2.6.2. Quasiparticle recombination .............................................................................. 39 2.6.3. Knock-on effects of changes in the energy distribution of quasiparticles...

Moseley, Richard William

43

Non-equilibrium Lorentz gas on a curved space  

E-Print Network (OSTI)

The periodic Lorentz gas with external field and iso-kinetic thermostat is equivalent, by conformal transformation, to a billiard with expanding phase-space and slightly distorted scatterers, for which the trajectories are straight lines. A further time rescaling allows to keep the speed constant in that new geometry. In the hyperbolic regime, the stationary state of this billiard is characterized by a phase-space contraction rate, equal to that of the iso-kinetic Lorentz gas. In contrast to the iso-kinetic Lorentz gas where phase-space contraction occurs in the bulk, the phase-space contraction rate here takes place at the periodic boundaries.

Felipe Barra; Thomas Gilbert

2007-01-12T23:59:59.000Z

44

Facilitated oriented spin models:some non equilibrium results  

E-Print Network (OSTI)

We analyze the relaxation to equilibrium for kinetically constrained spin models (KCSM) when the initial distribution $\

Nicoletta Cancrini; Fabio Martinelli; Roberto H. Schonmann; Cristina Toninelli

2008-10-23T23:59:59.000Z

45

Equilibrium and non-equilibrium emission of complex fragments  

Science Conference Proceedings (OSTI)

Complex fragment emission (Z{gt}2) has been studied in the reactions of 50, 80, and 100 MeV/u {sup 139}La + {sup 12}C, and 80 MeV/u {sup 139}La + {sup 27}Al, {sup nat}Cu, and {sup 197}Au. Charge, angle, and energy distributions were measured inclusively and in coincidence with other complex fragments, and were used to extract the source rapidities, velocity distributions, and cross sections. The experimental emission velocity distributions, charge loss distributions, and cross sections have been compared with calculations based on statistical compound nucleus decay. The binary signature of the coincidence events and the sharpness of the velocity distributions illustrate the primarily 2-body nature of the {sup 139}La + {sup 12}C reaction mechanism between 50 and 100 MeV/u. The emission velocities, angular distributions, and absolute cross sections of fragments of 20{le}Z{le}35 at 50 MeV/u, 19{le}Z{le}28 at 80 MeV/u, and 17{le}Z{le}21 at 100 MeV/u indicate that these fragments arise solely from the binary decay of compound nuclei formed in incomplete fusion reactions in which the {sup 139}La projectile picks up about one-half of the {sup 12}C target. In the 80 MeV/u {sup 139}La + {sup 27}Al, {sup nat}Cu, and {sup 197}Au reactions, the disappearance of the binary signature in the total charge and velocity distributions suggests and increase in the complex fragment and light charged particle multiplicity with increasing target mass. As in the 80 and 100 MeV/u {sup 139}La + {sup 12}C reactions, the lighter complex fragments exhibit anisotropic angular distributions and cross sections that are too large to be explained exclusively by statistical emission. 143 refs., 67 figs.

Bowman, D.R.

1989-08-01T23:59:59.000Z

46

Non-equilibrium effects and multiphase flow in porous media.  

E-Print Network (OSTI)

??We encounter flow in porous media, knowingly or otherwise, on a daily basis; percolation of precipitation into top soil, ground-water supplies obtained from aquifers (ground-water (more)

Aryana, Saman Afqahi.

2012-01-01T23:59:59.000Z

47

Symmetries and relaxations in non-equilibrium thermodynamics.  

E-Print Network (OSTI)

??Static thermodynamic susceptibilities obey symmetries that have been known for a very long time. These are the Maxwell relations. Less well-known are the symmetry properties (more)

DeSimone, Anthony Joseph Jr

2005-01-01T23:59:59.000Z

48

Search for the Neutrino Magnetic Moment in the Non-Equilibrium Reactor Antineutrino Energy Spectrum  

E-Print Network (OSTI)

We study the time evolution of the typical nuclear reactor antineutrino energy spectrum during reactor ON period and the decay of the residual antineutrino spectrum after reactor is stopped. We find that relevant variations of the soft recoil electron spectra produced via weak and magnetic ${\\widetilde {\

V. I. Kopeikin; L. A. Mikaelyan; V. V. Sinev

1999-04-19T23:59:59.000Z

49

Non-equilibrium fluctuations and mechanochemical couplings of a molecular motor  

E-Print Network (OSTI)

We investigate theoretically the violations of Einstein and Onsager relations, and the efficiency for a single processive motor operating far from equilibrium using an extension of the two-state model introduced by Kafri {\\em et al.} [Biophys. J. {\\bf 86}, 3373 (2004)]. With the aid of the Fluctuation Theorem, we analyze the general features of these violations and this efficiency and link them to mechanochemical couplings of motors. In particular, an analysis of the experimental data of kinesin using our framework leads to interesting predictions that may serve as a guide for future experiments.

A. W. C. Lau; D. Lacoste; K. Mallick

2007-07-30T23:59:59.000Z

50

Non-equilibrium fluctuations in frictional granular motor: experiments and kinetic theory  

E-Print Network (OSTI)

We report the study of a new experimental granular Brownian motor, inspired to the one published in [Phys. Rev. Lett. 104, 248001 (2010)], but different in some ingredients. As in that previous work, the motor is constituted by a rotating pawl whose surfaces break the rotation-inversion symmetry through alternated patches of different inelasticity, immersed in a gas of granular particles. The main novelty of our experimental setup is in the orientation of the main axis, which is parallel to the (vertical) direction of shaking of the granular fluid, guaranteeing an isotropic distribution for the velocities of colliding grains, characterized by a variance $v_0^2$. We also keep the granular system diluted, in order to compare with Boltzmann-equation-based kinetic theory. In agreement with theory, we observe for the first time the crucial role of Coulomb friction which induces two main regimes: (i) rare collisions (RC), with an average drift $\\ \\sim v_0^3$, and (ii) frequent collisions (FC), with $\\ \\sim v_0$. We also study the fluctuations of the angle spanned in a large time interval, $\\Delta \\theta$, which in the FC regime is proportional to the work done upon the motor. We observe that the Fluctuation Relation is satisfied with a slope which weakly depends on the relative collision frequency.

Andrea Gnoli; Alessandro Sarracino; Alberto Petri; Andrea Puglisi

2013-04-11T23:59:59.000Z

51

Non-equilibrium raft-like membrane domains under continuous recycling  

E-Print Network (OSTI)

We present a model for the kinetics of spontaneous membrane domain (raft) assembly that includes the effect of membrane recycling ubiquitous in living cells. We show that the domains have a broad power-law distribution with an average radius that scales with the 1/4 power of the domain lifetime when the line tension at the domain edges is large. For biologically reasonable recycling and diffusion rates the average domain radius is in the tens of nm range, consistent with observations. This represents one possible link between signaling (involving rafts) and traffic (recycling) in cells. Finally, we present evidence that suggests that the average raft size may be the same for all scale-free recycling schemes.

Matthew S. Turner; Pierre Sens; Nicholas D. Socci

2005-03-30T23:59:59.000Z

52

Study of Methane Reforming in Warm Non-Equilibrium Plasma Discharges  

E-Print Network (OSTI)

Utilization of natural gas in remote locations necessitates on-site conversion of methane into liquid fuels or high value products. The first step in forming high value products is the production of ethylene and acetylene. Non-thermal plasmas, due to their unique nonequilibrium characteristics, offer advantages over traditional methods of methane reforming. Different kinds of non-thermal plasmas are being investigated for methane reforming. Parameters of these processes like flow rate, discharge size, temperature and other variables determine efficiency of conversion. An efficient process is identified by a high yield and low specific energy of production for the desired product. A study of previous work reveals that higher energy density systems are more efficient for methane conversion to higher hydrocarbons as compared to low energy density systems. Some of the best results were found to be in the regime of warm discharges. Thermal equilibrium studies indicate that higher yields of ethylene are possible with an optimal control of reaction kinetics and fast quenching. With this idea, two different glow discharge reactor systems are designed and constructed for investigation of methane reforming. A counter flow micro plasma discharge system was used to investigate the trends of methane reforming products and the control parameters were optimized to get best possible ethylene yields while minimizing its specific energy. Later a magnetic glow discharge system is used and better results are obtained. Energy costs lower than thermal equilibrium calculations were achieved with magnetic glow discharge systems for both ethylene and acetylene. Yields are obtained from measurements of product concentrations using gas chromatography and power measurements are done using oscilloscope. Energy balance and mass balances are performed for product measurement accuracy and carbon deposition calculations. Carbon deposition is minimized through control of the temperature and residence time conditions in magnetic glow discharges. Ethylene production is observed to have lower specific energies at higher powers and lower flow rates in both reactors. An ethylene selectivity of 40 percent is achieved at an energy cost of 458MJ/Kg and an input energy cost of 5 MJ/Kg of methane.

Parimi, Sreekar

2010-12-01T23:59:59.000Z

53

High-Efficiency Solid State Cooling Technologies: Non-Equilibrium Asymmetic Thermoelectrics (NEAT) Devices  

SciTech Connect

BEETIT Project: Sheetak is developing a thermoelectric-based solid state cooling system to replace typical air conditioners that use vapor compression to cool air. With noisy mechanical components, vapor compression systems use a liquid refrigerant to circulate within the air conditioner, absorb heat, and pump the heat out into the external environment. With no noisy moving parts or polluting refrigerants, thermoelectric systems rely on an electrical current being passed through the junction of the two different conducting materials to change temperature. Using advanced semiconductor technology, Sheetak is improving solid state cooling systems by using proprietary thermoelectric materials along with other innovations to achieve significant energy efficiency. Sheetaks new design displaces compressor-based technology; improves reliability; and decreases energy usage. Sheetaks use of semiconductor manufacturing methods leads to less material usefacilitating cheaper production.

2010-09-01T23:59:59.000Z

54

AIAA 2002-3663 A Non-Equilibrium Numerical Study of  

E-Print Network (OSTI)

by comparing the results of Fig. 2 with the Rechester­ Rosenbluth model, QeR ve(B~ /B0)2 L . Using the spectrum

Choueiri, Edgar

55

Multiple temperature kinetic model and gas-kinetic method for hypersonic non-equilibrium flow computations  

Science Conference Proceedings (OSTI)

It is well known that for increasingly rarefied flowfields, the predictions from continuum formulation, such as the Navier-Stokes equations lose accuracy. For the high speed diatomic molecular flow in the transitional regime, the inaccuracies are partially ... Keywords: Gas-kinetic method, Hypersonic and rarefied flows, Multiple temperature kinetic model

Kun Xu; Xin He; Chunpei Cai

2008-07-01T23:59:59.000Z

56

Understanding the response behavior of potentiometric gas sensors for non-equilibrium gas mixtures  

DOE Green Energy (OSTI)

Many applications of gas sensors require concentration measurements of reactive gases in mixtures that are out of thermodynamic equilibrium. These applications include: hydrogen and hydrocarbon fuel gas sensors operating in ambient air for explosion hazard detection, carbon monoxide detection in ambient air for health protection, combustion efficiency sensors for stoichiometry control, and nitric oxide sensors for air pollution monitoring. Many potentiometric and amperometric electrochemical sensor technologies have been developed for these applications. A class of the potentiometric sensors developed for gas mixtures are the non-Nerstian sensors. This presentation defines a categorization and theoretical analysis of three distinct electrochemical processes that can produce a non-Nernstian sensor response.

Garzon, F. H. (Fernando H.); Mukundan, R. (Rangachary); Brosha, E. L. (Eric L.)

2002-01-01T23:59:59.000Z

57

Spectral-Lagrangian methods for collisional models of non-equilibrium statistical states  

Science Conference Proceedings (OSTI)

We propose a new spectral Lagrangian based deterministic solver for the non-linear Boltzmann transport equation (BTE) in d-dimensions for variable hard sphere (VHS) collision kernels with conservative or non-conservative binary interactions. The method ... Keywords: Boltzmann transport equation, Conservative/non-conservative deterministic method, FFT, Lagrangian optimization, Spectral method

Irene M. Gamba; Sri Harsha Tharkabhushanam

2009-04-01T23:59:59.000Z

58

Crowding effects in non-equilibrium transport through nano-channels  

E-Print Network (OSTI)

Transport through nano-channels plays an important role in many biological processes and industrial applications. Gaining insights into the functioning of biological transport processes and the design of man-made nano-devices requires an understanding of the basic physics of such transport. A simple exclusion process has proven to be very useful in ex- plaining the properties of several artificial and biological nano-channels. It is particularly useful for modeling the influence of inter-particle interactions on transport characteristics. In this paper, we explore several models of the exclusion process using a mean field approach and computer simulations. We examine the effects of crowding inside the channel and its immediate vicinity on the mean flux and the transport times of single molecules. Finally, we discuss the robustness of the theory's predictions with respect to the crucial characteristics of the hindered diffusion in nano-channels that need to be included in the model.

Anton Zilman; Golan Bel

2010-07-15T23:59:59.000Z

59

Representing equilibrium and non-equilibrium convection in large-scale models  

Science Conference Proceedings (OSTI)

A new diagnostic convective closure, which is dependent on the convective available potential energy (CAPE), is derived under the quasi-equilibrium assumption for the free troposphere subject to boundary-layer forcing. The closure involves a ...

Peter Bechtold; Noureddine Semane; Philippe Lopez; Jean-Pierre Chaboureau; Anton Beljaars; Niels Bormann

60

The Development of a Non-Equilibrium Dispersed Flow Film Boiling Heat Transfer Modeling Package.  

E-Print Network (OSTI)

??The dispersed flow film boiling (DFFB) heat transfer regime is important to several applications including cryogenics, rocket engines, steam generators, and in the safety analysis (more)

Meholic, Michael

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Thermophysical properties of nitrogen plasmas under thermal equilibrium and non-equilibrium conditions  

SciTech Connect

Calculated thermophysical properties of nitrogen plasmas in and out of thermal equilibrium are presented. The cut-off of the partition functions due to the lowering of the ionization potential has been taken into account, together with the contributions from different core excited electronic states. The species composition and thermodynamic properties are determined numerically using the Newton-Raphson iterative method, taking into account the corrections due to Coulomb interactions. The transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated using the most recent collision interaction potentials by adopting Devoto's electron and heavy particle decoupling approach, expanded to the third-order approximation (second-order for viscosity) in the framework of Chapman-Enskog method. Results are presented in the pressure range of 0.1 atm-10 atm and in electron temperature range from 300 to 40 000 K, with the ratio of electron temperature to heavy-particle temperature varied from 1 to 20. Results are compared with those from previous works, and the influences of different definitions of the Debye length are discussed.

Wang Weizong [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Rong Mingzhe [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Yan, J. D.; Spencer, Joseph W. [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Murphy, A. B. [CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield NSW 2070 (Australia)

2011-11-15T23:59:59.000Z

62

The Non-Equilibrium Thermodynamic Environment and Prigogines Dissipative Structures  

E-Print Network (OSTI)

This essay is based on the fundmental assumption that any physical system of synergetic parts is a thermodynamic system. The universality of thermodynamics is due to the fact that thermodynamic homogeneous properties, such as pressure, temperature and their analogs, do not depend upon size or shape. That is, thermodynamics is a topological (not a geometrical) theory. By use of Cartans methods of exterior differential forms and their topological properties of closure, it is possible to define and construct examples for the universal concepts of: [1] Continuous Topological Evolution of topological properties- which in effect is a dynamical version of the First Law. [2] Topological Torsion and Pfaff Topological Dimension- which distinguishes equilibrium (PTD 2, TT 6 = 0). [3] A Topological Thermodynamic Environment- of PTD = 4. [4] Thermodynamic irreversible processes, which cause self-similar evolution in the environment, and emergence of self-organized states of PTD = 3 as topological defects

R. M. Kiehn

2008-01-01T23:59:59.000Z

63

Elliptic Flow from Non-equilibrium Initial Condition with a Saturation Scale  

E-Print Network (OSTI)

A current goal of relativistic heavy ion collisions experiments is the search for a Color Glass Condensate as the limiting state of QCD matter at very high density. In viscous hydrodynamics simulations, a standard Glauber initial condition leads to estimate $4\\pi \\eta/s \\sim 1$, while a Color Glass Condensate modeling leads to at least a factor of 2 larger $\\eta/s$. Within a kinetic theory approach based on a relativistic Boltzmann-like transport simulation, we point out that the out-of-equilibrium initial distribution proper of a Color Glass Condensate reduces the efficiency in building-up the elliptic flow. Our main result at RHIC energy is that the available data on $v_2$ are in agreement with a $4\\pi \\eta/s \\sim 1$ also for Color Glass Condensate initial conditions, opening the possibility to describe self-consistently also higher order flow, otherwise significantly underestimated, and to pursue further the search for signatures of the Color Glass Condensate.

M. Ruggieri; F. Scardina; S. Plumari; V. Greco

2013-03-13T23:59:59.000Z

64

Modeling of species and charge transport in Li-Ion batteries based on non-equilibrium thermodynamics  

Science Conference Proceedings (OSTI)

In order to improve the design of Li ion batteries the complex interplay of various physical phenomena in the active particles of the electrodes and in the electrolyte has to be balanced. The separate transport phenomena in the electrolyte and in the ...

Arnulf Latz; Jochen Zausch; Oleg Iliev

2010-08-01T23:59:59.000Z

65

Chemical freeze-outs of strange and non-strange particles and residual chemical non-equilibrium  

E-Print Network (OSTI)

We propose an elaborate version of the hadron resonance gas model with the combined treatment of separate chemical freeze-outs for strange and non-strange hadrons and with an additional \\gamma_{s} factor which accounts for the remaining strange particle non-equilibration. Two sets of chemical freeze-outs parameters are connected by the conservation laws of entropy, baryonic charge, isospin projection and strangeness. The developed approach enables us to perform a high-quality fit of the hadron multiplicity ratios for AGS, SPS and RHIC energies with total \\chi^2/dof \\simeq 1.05. A special attention is paid to a complete description of the Strangeness Horn. A well-known \\bar p, \\bar \\Lambda and \\bar \\Xi selective suppression problem is also discussed.

K. A. Bugaev; D. R. Oliinychenko; V. V. Sagun; A. I. Ivanytskyi; J. Cleymans; E. G. Nikonov; G. M. Zinovjev

2013-12-18T23:59:59.000Z

66

Homogeneous Non-Equilibrium Molecular Dynamics Methods for Calculating the Heat Transport Coefficient of Solids and Mixtures  

E-Print Network (OSTI)

b k ? ? T versible processes of heat transfer and diffusion,irreversible process of diffusion and heat transfer in theIntroduction Heat conduction is a process involving transfer

Mandadapu, Kranthi Kiran

2011-01-01T23:59:59.000Z

67

Homogeneous Non-Equilibrium Molecular Dynamics Methods for Calculating the Heat Transport Coefficient of Solids and Mixtures  

E-Print Network (OSTI)

Heat Conduction in an ElasticHeat Conduction in Liquid Mixtures . . . . . . .1 Introduction Heat conduction is a process involving

Mandadapu, Kranthi Kiran

2011-01-01T23:59:59.000Z

68

Homogeneous Non-Equilibrium Molecular Dynamics Methods for Calculating the Heat Transport Coefficient of Solids and Mixtures  

E-Print Network (OSTI)

of flexible molecules - Butane. Molecular Physics, 81(6):in polyatomic fluids: n-Butane as an illustration. Chemicalfor two models of liquid Butane. Chemical Physics, 198(1-2):

Mandadapu, Kranthi Kiran

2011-01-01T23:59:59.000Z

69

High Metallicity and Non-Equilibrium Chemistry in the Dayside Atmosphere of Hot-Neptune Gj 436b  

E-Print Network (OSTI)

We present a detailed analysis of the dayside atmosphere of the hot-Neptune GJ 436b, based on recent Spitzer observations. We report statistical constraints on the thermal and chemical properties of the planetary atmosphere, ...

Madhusudhan, Nikku

70

Application of Semi-Grand Canonical Monte Carlo (SGMC) methods to describe non-equilibrium polymer systems  

E-Print Network (OSTI)

Understanding the structure of materials, and how this structure affects their properties, is an important step towards the understanding that is necessary in order to apply computational methods to the end of designing ...

Bernardin, Frederick E

2007-01-01T23:59:59.000Z

71

Chapter 6: Simulation of ... absorbers: the behaviour of methanol and non-equilibrium stage modeling. Simulation of industrial formaldehyde absorbers  

E-Print Network (OSTI)

jobshavebeenwrittenonourVB6UHR EWF lithography tool during the past year. Working with industry Working through the James

Groningen, Rijksuniversiteit

72

Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task I  

DOE Green Energy (OSTI)

Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)

Not Available

1981-11-01T23:59:59.000Z

73

Evaluation of technical feasibility of closed-cycle non-equilibrium MHD power generation with direct coal firing. Final report, Task 1  

DOE Green Energy (OSTI)

Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal fired, closed cycle, magnetohydrodynamic power generation are detailed. These accomplishments relate to all system aspects of a CCMHD power generation system including coal combustion, heat transfer to the MHD working fluid, MHD power generation, heat and cesium seed recovery and overall systems analysis. Direct coal firing of the combined cycle has been under laboratory development in the form of a high slag rejection, regeneratively air cooled cyclone coal combustor concept, originated within this program. A hot bottom ceramic regenerative heat exchanger system was assembled and test fired with coal for the purposes of evaluating the catalytic effect of alumina on NO/sub x/ emission reduction and operability of the refractory dome support system. Design, procurement, fabrication and partial installation of a heat and seed recovery flow apparatus was accomplished and was based on a stream tube model of the full scale system using full scale temperatures, tube sizes, rates of temperature change and tube geometry. Systems analysis capability was substantially upgraded by the incorporation of a revised systems code, with emphasis on ease of operator interaction as well as separability of component subroutines. The updated code was used in the development of a new plant configuration, the Feedwater Cooled (FCB) Brayton Cycle, which is superior to the CCMHD/Steam cycle both in performance and cost. (WHK)

Not Available

1981-11-01T23:59:59.000Z

74

SciTech Connect: "smart grid"  

Office of Scientific and Technical Information (OSTI)

Fe Atomic Data for Non-equilibrium Ionization Plasmas Citation Details In-Document Search Title: Fe Atomic Data for Non-equilibrium Ionization Plasmas...

75

Technology@TMS: Online Article  

Science Conference Proceedings (OSTI)

Molar volume, density, and thermal expansion; Scheil-Gulliver (non-equilibrium) solidification simulations; Thermochemical data such as enthalpies, heat...

76

Engineering model reduction of bio-chemical kinetic David Csercsik, Katalin M. Hangos  

E-Print Network (OSTI)

of Hydrosystems Chemical and Thermal Non-Equilibrium: Kinetic Mass & Energy Transfer Motivation Modeling Non is actually driven by difference in chemical potential influence of thermal non-equilibrium on kinetic mass situation of clear non-equilibrium extending range of applicability Support of the German Research

Gorban, Alexander N.

77

Microsoft PowerPoint - Malhotra-ARRA-February-2011.pptx  

NLE Websites -- All DOE Office Websites (Extended Search)

MONITORING OF STORED CO 2 IN ORGANIC ROCKS UNDER NON- EQUILIBRIUM CONDITIONS Southern Illinois University-Carbondale Presenter: Vivak (Vik) Malhotra Department of Physics...

78

ARPA-E Technology Showcase: Project Spotlight | Department of...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

that use half the energy and avoid using potent greenhouse gas coolants of traditional vapor-compression refrigeration systems. Sheetak's Non-Equilibrium Asymmetric...

79

Present and Future Computing Requirements Radiative Transfer...  

NLE Websites -- All DOE Office Websites (Extended Search)

radiative shock (e.g., ensman 1994) gas temperature radiation temperature Local Thermodynamic Equilibrium (LTE) non-equilibrium (NLTE) CaII microphysics 1GB atomic data...

80

Interface Role in the Shock Response of Cu/Nb Metallic Multilayers  

Science Conference Proceedings (OSTI)

Non-equilibrium MD simulations of the shock loading of Cu/Nb multilayers containing exclusively one interface structure or the other confirm the key role which...

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

* Thermodynamics in confinement * Non-equilibrium analysis * Kinetics in confinement * Multiphase transport Keys: Energy Forms + Scales + Sediment Mineral surface 1D - interface...

82

Long-term Atomistic Simulation of Heat Conduction and Mass ...  

Science Conference Proceedings (OSTI)

This non-equilibrium thermodynamics model is then coupled with discrete kinetic models of Onsager type which governs heat conduction and mass transport at...

83

NSLS II: Growth and Processing of Advanced Materials  

NLE Websites -- All DOE Office Websites (Extended Search)

is a non-equilibrium phenomenon governed by a competition between kinetics and thermodynamics. The figure illustrates common themes in thin film growth processes and methods....

84

Study of thermal properties of graphene-based structures using the force constant method  

Science Conference Proceedings (OSTI)

The thermal properties of graphene-based materials are theoretically investigated. The fourth-nearest neighbor force constant method for phonon properties is used in conjunction with both the Landauer ballistic and the non-equilibrium Green's function ... Keywords: Force constant method, Graphene, Graphene antidots, Non-equilibrium Green's function, Thermal properties

Hossein Karamitaheri; Neophytos Neophytou; Mahdi Pourfath; Hans Kosina

2012-03-01T23:59:59.000Z

85

EFf!!$L, . United States Government Department of Energy  

Office of Legacy Management (LM)

903-8 149) SJRJECT: The Former Atomic Energy Commission and the Manhattan Engineer District Sites in Dayton, Ohio TO: W . Dennison. GC-5 1 I a m attaching two copies of the...

86

--No Title--  

NLE Websites -- All DOE Office Websites (Extended Search)

I will discuss the possibilities to reveal non-equilibrium states behind merger shock fronts in galaxy clusters from X-ray observations, the 3D temperature structure of...

87

Nonequilibrium Thermodynamics of Porous Electrodes  

E-Print Network (OSTI)

We reformulate and extend porous electrode theory for non-ideal active materials, including those capable of phase transformations. Using principles of non-equilibrium thermodynamics, we relate the cell voltage, ionic ...

Ferguson, Todd Richard

88

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

E-Print Network (OSTI)

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 ...

Beretta, Gian Paolo

89

Thermodynamics with 3 Spins  

E-Print Network (OSTI)

Glauber dynamics, applied to the one-dimensional Ising model, provides a tractable model for the study of non-equilibrium, many-body processes driven by a heat bath

Eward May; Jack L. Uretsky

2009-12-21T23:59:59.000Z

90

Synthesis, Properties and Applications of Noble Metal Nanostructures  

Science Conference Proceedings (OSTI)

And such non-equilibrium growth process is affected by many factors, such as size ... Improved Field Emission Characteristics of Nano-Structured Carbon Based Thin Films ... Synthesis and Structural Analysis of Nickel-Doped Titanium Dioxide...

91

RussiaSNL2-web.indd  

National Nuclear Security Administration (NNSA)

Extending Non-Equilibrium Molecular Dynamics Extending Non-Equilibrium Molecular Dynamics Simulation Methods Principal Investigators: John Aidun (SNL) and Genri Norman (JIHT) Project Description Novel nonequilibrium molecular dynamics (NEMD) simulation methods are being extended and applied in four areas of mutual interest to Sandia and Joint Institute for High Temperatures, Russian Academy of Sciences (JIHT RAS). NEMD is being applied to (1) understanding relaxation and equilibration in non-ideal, nondegenerate plasmas; (2) characterizing melting or cavitation of condensed matter systems that are super-heated or under hydrostatic tension; (3) devising classical interaction potentials that can represent changing bonding character as a system evolves; and (4) investigating the mechanisms of

92

Teaching the Environment to Control Quantum Systems  

E-Print Network (OSTI)

A non-equilibrium, generally time-dependent, environment whose form is deduced by optimal learning control is shown to provide a means for incoherent manipulation of quantum systems. Incoherent control by the environment (ICE) can serve to steer a system from an initial state to a target state, either mixed or in some cases pure, by exploiting dissipative dynamics. Implementing ICE with either incoherent radiation or a gas as the control is explicitly considered, and the environmental control is characterized by its distribution function. Simulated learning control experiments are performed with simple illustrations to find the shape of the optimal non-equilibrium distribution function that best affects the posed dynamical objectives.

Alexander Pechen; Herschel Rabitz

2006-09-12T23:59:59.000Z

93

Heavy ions and string theory  

E-Print Network (OSTI)

We review a selection of recent developments in the application of ideas of string theory to heavy ion physics. Our topics divide naturally into equilibrium and non-equilibrium phenomena. On the non-equilibrium side, we discuss generalizations of Bjorken flow, numerical simulations of black hole formation in asymptotically anti-de Sitter geometries, equilibration in the dual field theory, and hard probes. On the equilibrium side, we summarize improved holographic QCD, extraction of transport coefficients, inclusion of chemical potentials, and approaches to the phase diagram. We close with some possible directions for future research.

Oliver DeWolfe; Steven S. Gubser; Christopher Rosen; Derek Teaney

2013-04-29T23:59:59.000Z

94

Resistances for heat and mass transfer through a liquid-vapor interface in a binary mixture  

E-Print Network (OSTI)

In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid-vapor interface in a binary mixture. We use two methods, the direct calculation from the actual non-equilibrium solution and integral relations, derived earlier. We verify, that integral relations, being a relatively faster and cheaper method, indeed gives the same results as the direct processing of a non-equilibrium solution. Furthermore we compare the absolute values of the interfacial resistances with the ones obtained from kinetic theory. Matching the diagonal resistances for the binary mixture we find that kinetic theory underestimates the cross coefficients. The heat of transfer is as a consequence correspondingly larger.

Kirill Glavatskiy; Dick Bedeaux

2010-08-20T23:59:59.000Z

95

Resistances for heat and mass transfer through a liquid-vapor interface in a binary mixture  

E-Print Network (OSTI)

In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid-vapor interface in a binary mixture. We use two methods, the direct calculation from the actual non-equilibrium solution and integral relations, derived earlier. We verify, that integral relations, being a relatively faster and cheaper method, indeed gives the same results as the direct processing of a non-equilibrium solution. Furthermore we compare the absolute values of the interfacial resistances with the ones obtained from kinetic theory. Matching the diagonal resistances for the binary mixture we find that kinetic theory underestimates the cross coefficients. The heat of transfer is as a consequence correspondingly larger.

Glavatskiy, Kirill

2010-01-01T23:59:59.000Z

96

LFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

Page 1 of 31 Page 1 of 31 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

97

Supporting Material for: Capillary-like Fluctuations of a Solid-Liquid Interface in a Non-Cohesive Granular System  

E-Print Network (OSTI)

In this supplementary paper we present some details on the solid-liquid interface detection, the deduction of the non-equilibrium free energy, the analysis of the granular temperature and energy per mode, a validation of the small slope approximation, a description of the Langevin dynamics, and the error analysis.

Li-Hua Luu; Gustavo Castillo; Nicols Mujica; Rodrigo Soto

2013-04-09T23:59:59.000Z

98

The effect of grain boundary segregation of boron in cast alloy 718 on HAZ microfissuring -- a SIMS analysis  

SciTech Connect

Secondary ion mass spectroscopy (SIMS) has been used to examine grain boundary segregation in cast alloy 718. The relationship between the boron segregation and the microfissuring tendency in heat affected zones (HAZ) around electron beam welds is discussed in this study. It is concluded that two types of segregation, namely equilibrium and non-equilibrium segregation, occurred during the homogenization heat treatment of the base material. Water quenching after the homogenization treatment inhibited non-equilibrium segregation of boron and other trace elements owing to insufficient time for diffusion of solute-vacancy complexes to occur. Intermediate cooling rates such as air cooling enhanced both non-equilibrium and equilibrium segregation, since equilibrium segregation occurred during holding at the heat treatment temperature. The value of net segregation produced by a combination of equilibrium segregation and non-equilibrium segregation varied with temperature in a U-shape. The nature of the grain boundary in the cast alloy was examined by using an electron backscattered diffraction (EBSD) technique and it was found that 93% of the grain boundaries were of the random type ({Sigma} > 49). The weldability of this alloy was found to be closely related to the grain boundary segregation of boron, i.e., the variation of HAZ total crack length (TCL) with pre-welding heat treatment temperatures has a trend similar to that of boron segregation with temperature after air cooling. Mechanisms for the effect of boron on HAZ microfissuring have been proposed.

Huang, X.; Chaturvedi, M.C. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Mechanical and Industrial Engineering; Richards, N.L. [Bristol Aerospace Ltd., Winnipeg, Manitoba (Canada); Jackman, J. [CANMET, Ottawa, Ontario (Canada)

1997-08-01T23:59:59.000Z

99

Boundary stability under nonequilibrium conditions. Final report  

Science Conference Proceedings (OSTI)

Summaries of research accomplished are given for the following areas: Morphological (Diffusional) Stability; A New Algorithm for Numerical Modeling of Non-equilibrium Materials Behavior; A Unified Treatment of Single and Microcrystalline Film Edge Instabilities; and Validation of the Structure Based Grain Boundary Diffusion/Migration Model.

Hackney, S.A.; Lee, J.K.; Plichta, M.R.

1999-08-01T23:59:59.000Z

100

Heat conduction in relativistic systems: alternatives and perspectives  

E-Print Network (OSTI)

The non-equilibrium thermodynamics of relativistic systems have a rich phenomenology. The simplest phenomenon in the class of dissipative processes is that of heat. This letter presents a brief summary of the efforts made to tackle the problem of relativistic heat conduction. In particular, we focus on the multi-fluid approach to relativistic dissipation.

Lopez-Monsalvo, C S

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

A Model of Heat Conduction  

E-Print Network (OSTI)

We define a deterministic ``scattering'' model for heat conduction which is continuous in space, and which has a Boltzmann type flavor, obtained by a closure based on memory loss between collisions. We prove that this model has, for stochastic driving forces at the boundary, close to Maxwellians, a unique non-equilibrium steady state.

Collet, Pierre

2008-01-01T23:59:59.000Z

102

Heat conduction in relativistic systems: alternatives and perspectives  

E-Print Network (OSTI)

The non-equilibrium thermodynamics of relativistic systems have a rich phenomenology. The simplest phenomenon in the class of dissipative processes is that of heat. This letter presents a brief summary of the efforts made to tackle the problem of relativistic heat conduction. In particular, we focus on the multi-fluid approach to relativistic dissipation.

C. S. Lopez-Monsalvo

2010-11-30T23:59:59.000Z

103

CPFFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 20 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

104

LFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

Dated 5-20-13 Dated 5-20-13 Subcontract No. 241314 Page 1 of 19 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012 - Deviation) ........................................................................................ 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 4 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

105

EFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 26 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2 AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Apr 2013) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

106

TM Exhibit A General Conditions (Rev. 7.3, 9-27-13)  

NLE Websites -- All DOE Office Websites (Extended Search)

3, 9/27/13) Exhibit A General Conditions 3, 9/27/13) Exhibit A General Conditions Page 1 of 20 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ............................................................................................

107

CONST Ex A (Rev. 5.1, 4/9/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 39 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2 AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Apr 2013) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

108

SFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 16 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

109

IDIQ BS Ex A (Rev. 3.2, 6/14/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 19 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) ......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ....... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................ 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) .................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ........................................................................................... 4 GC-6 ORDER OF PRECEDENCE (Jun 2009) ................................................................................... 5

110

Time and Materials Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 20 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

111

D-B CONST Ex A (Rev. 4.1, 4/9/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 40 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2 AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Apr 2013) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

112

CPFFS Exhibit A General Conditions (Rev. 8.3, 9-27-13)  

NLE Websites -- All DOE Office Websites (Extended Search)

3, 9/27/13) Exhibit A General Conditions 3, 9/27/13) Exhibit A General Conditions Page 1 of 21 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ............................................................................................

113

IDIQ BS Ex A (Rev. 3.1, 4/9/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 31 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) ......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ....... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................ 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) .................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ........................................................................................... 4 GC-6 ORDER OF PRECEDENCE (Jun 2009) ................................................................................... 5

114

Thormod Henriksen og Ingolf Kanestrm In my view, we are not doing as well as we could  

E-Print Network (OSTI)

periodicity during the Holocene period has been disputed (e.g. Schulz and Paul, 2002; Risebro- bakken et al composition of planktonic foraminifers (Duplessy et al., 2001; Risebro- bakken et al., 2003; Sarnthein et al core (LBC; 0.4 m long; ? 40 cm), a giant gravity (GGC; 2.7 m; ? 30 cm), and a gravity core (GC; 5.6 m

Sahay, Sundeep

115

R&D Ex A (Rev. 3.1, 4/9/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 31 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

116

EFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 39 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2 AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Apr 2013) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

117

AES Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 18 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

118

SFS Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 29 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-1 DEFINITIONS (Aug 2012) .......................................................................................................... 3 GC-2A AUTHORIZED REPRESENTATIVES, COMMUNICATIONS AND NOTICES (Jan 2010) ........................................................................................................................................... 3 GC-3 INDEPENDENT CONTRACTOR (Jun 2009) ............................................................................. 4 GC-4 SUBCONTRACT INTERPRETATION (Jun 2009) ...................................................................... 4 GC-5 NOTICE TO PROCEED (Jul 2011)............................................................................................. 4

119

Abstract for Gouranga C. Nayak  

NLE Websites -- All DOE Office Websites (Extended Search)

Gouranga C. Nayak Gouranga C. Nayak Gluon Propagator and Magnetic Screening Mass at One Loop Level in Non-Equilibrium QCD Using closed-time path integral formalism I will show for the first time that the magnetic screening mass at one loop level in QED and QCD is non-zero as long as the distribution function is anisotropic in momentum space. For isotropic distribution function such as the thermal distribution function the magnetic screening mass at one loop level is zero which is consistent with finite temperature field theory results. I will also show that the same non-zero magnetic screening results is also obtained by using transport equation approach. I will present a resummed (at one loop level of self energy) gluon propagator in any arbitary covariant gauge in non-equilibrium in any arbitary moving frame which can be used in the

120

On the Accuracy of Explicit Finite-Volume Schemes for Fluctuating Hydrodynamics  

E-Print Network (OSTI)

This paper describes the development and analysis of finite-volume methods for the Landau-Lifshitz Navier-Stokes (LLNS) equations and related stochastic partial differential equations in fluid dynamics. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by the addition of white-noise fluxes whose magnitudes are set by a fluctuation-dissipation relation. Originally derived for equilibrium fluctuations, the LLNS equations have also been shown to be accurate for non-equilibrium systems. Previous studies of numerical methods for the LLNS equations focused primarily on measuring variances and correlations computed at equilibrium and for selected non-equilibrium flows. In this paper, we introduce a more systematic approach based on studying discrete equilibrium structure factors for a broad class of explicit linear finite-volume schemes. This new approach provides a better characterization of the accuracy of a spatio-temporal discretization as a function of wavenumber and frequency, ...

Donev, A; Garca, A L; Bell, J B

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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121

Quantification of Order in the Lennard-Jones System  

E-Print Network (OSTI)

We conduct a numerical investigation of structural order in the shifted-force Lennard-Jones system by calculating metrics of translational and bond-orientational order along various paths in the phase diagram covering equilibrium solid, liquid, and vapor states. A series of non-equilibrium configurations generated through isochoric quenches, isothermal compressions, and energy minimizations are also considered. Simulation results are analyzed using an ordering map representation [Torquato et al., Phys. Rev. Lett. 84, 2064 (2000); Truskett et al., Phys. Rev. E 62, 993 (2000)] that assigns to both equilibrium and non-equilibrium states coordinates in an order metric plane. Our results show that bond-orientational order and translational order are not independent for simple spherically symmetric systems at equilibrium. We also demonstrate quantitatively that the Lennard-Jones and hard sphere systems sample the same configuration space at supercritical densities. Finally, we relate the structural order found in fast-quenched and minimum-energy configurations (inherent structures).

Jeffrey R. Errington; Pablo G. Debenedetti; Salvatore Torquato

2002-08-20T23:59:59.000Z

122

Electro-hydrodynamics of binary electrolytes driven by modulated surface potentials  

E-Print Network (OSTI)

We study the electro-hydrodynamics of the Debye screening layer that arises in an aqueous binary solution near a planar insulating wall when applying a spatially modulated AC-voltage. Combining this with first order perturbation theory we establish the governing equations for the full non-equilibrium problem and obtain analytic solutions in the bulk for the pressure and velocity fields of the electrolyte and for the electric potential. We find good agreement between the numerics of the full problem and the analytics of the linear theory. Our work provides the theoretical foundations of circuit models discussed in the literature. The non-equilibrium approach also reveals unexpected high-frequency dynamics not predicted by circuit models.

N. A. Mortensen; L. H. Olesen; L. Belmon; H. Bruus

2004-07-07T23:59:59.000Z

123

Holographic Ricci dark energy and generalized second law  

E-Print Network (OSTI)

We explore the validity of the generalized second law (GSL) of thermodynamics in flat FRW universe with apparent horizon and event horizon as the boundary. We found that in a universe with holographic Ricci dark energy and dark matter, interacting with each other, the GSL is satisfied at the apparent horizon and partially satisfied at the event horizon under thermal equilibrium conditions. We also analyses the GSL under non-equilibrium conditions and shows that the fulfillment of GSL at the apparent horizon implies that the temperature of the dark energy is greater than that of the horizon. Thus there occurs a flow of dark energy towards the apparent horizon. As a result the entropy of the dark energy decreases and that of horizon increases. This is verified by finding the evolution of the dark energy entropy and horizon entropy in a dark energy dominated universe under non-equilibrium conditions.

Titus K Mathew; P. Praseetha

2013-11-19T23:59:59.000Z

124

Repeated interactions in open quantum systems  

E-Print Network (OSTI)

Analyzing the dynamics of open quantum systems has a long history in mathematics and physics. Depending on the system at hand, basic physical phenomena that one would like to explain are, for example, convergence to equilibrium, the dynamics of quantum coherences (decoherence) and quantum correlations (entanglement), or the emergence of heat and particle fluxes in non-equilibrium situations. From the mathematical physics perspective, one of the main challenges is to derive the irreversible dynamics of the open system, starting from a unitary dynamics of the system and its environment. The repeated interactions systems considered in these notes are models of non-equilibrium quantum statistical mechanics. They are relevant in quantum optics, and more generally, serve as a relatively well treatable approximation of a more difficult quantum dynamics. In particular, the repeated interaction models allow to determine the large time (stationary) asymptotics of quantum systems out of equilibrium.

Laurent Bruneau; Alain Joye; Marco Merkli

2013-05-11T23:59:59.000Z

125

PROPERTIES AND NANOSTRUCTURES OF MATERIALS PROCESSED BY SPD TECHNIQUES  

Science Conference Proceedings (OSTI)

Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. It demonstrates the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and high- and low-angle grain boundaries in equilibrium or non-equilibrium states. This paper reviews the mechanical properties and the defect structures of SPD-processed nanostructured materials. Keywords: strength, ductility, nanostructures, SPD, non-equilibrium grain boundary

Liao, Xiaoshan; Huang, J. (Jianyu); Zhu, Y. T. (Yuntian Theodore)

2001-01-01T23:59:59.000Z

126

Transport Characteristics of Molecular Motors  

E-Print Network (OSTI)

Properties of transport of molecular motors are investigated. A simplified model based on the concept of Brownian ratchets is applied. We analyze a stochastic equation of motion by means of numerical methods. The transport is systematically studied with respect to its energetic efficiency and quality expressed by an effective diffusion coefficient. We demonstrate the role of friction and non-equilibrium driving on the transport quantifiers and identify regions of a parameter space where motors are optimally transported.

Machura, Lukasz; Luczka, Jerzy; 10.1016/j.biosystems.2008.05.033

2011-01-01T23:59:59.000Z

127

Generalized Kraus Operators and Generators of Quantum Dynamical Semigroups  

E-Print Network (OSTI)

Quantum dynamical semigroups play an important role in the description of physical processes such as diffusion, radiative decay or other non-equilibrium events. Taking strongly continuous and trace preserving semigroups into consideration, we show that, under a special criterion, the generator of such a group admits a certain generalized standard form, thereby shedding new light on known approaches in this direction. Furthermore, we illustrate our analysis in concrete examples.

Sabina Alazzawi; Bernhard Baumgartner

2013-06-19T23:59:59.000Z

128

Entropy production along a stochastic trajectory and an integral fluctuation theorem  

E-Print Network (OSTI)

For stochastic non-equilibrium dynamics like a Langevin equation for a colloidal particle or a master equation for discrete states, entropy production along a single trajectory is studied. It involves both genuine particle entropy and entropy production in the surrounding medium. The integrated sum of both $\\Delta s\\t$is shown to obey a fluctuation theorem $ =1$ for arbitrary initial conditions and arbitrary time-dependent driving over a finite time interval.

Udo Seifert

2005-03-29T23:59:59.000Z

129

From shock waves to Brownian motion and 1/f-noise in gas  

E-Print Network (OSTI)

A formally exact relation is derived which connects thermodynamically non-equilibrium evolution of gas density distribution after its arbitrary strong spatially non-uniform perturbation and evolution of many-particle correlations between path of some marked particle and its surroundings in equilibrium gas. This relation directly confirms significance of the many-particle correlations even under the Boltzmann-Grad limit and thus validates the earlier suggested revision of kinetics.

Yuriy E. Kuzovlev

2007-05-31T23:59:59.000Z

130

Weak coupling limits in a stochastic model of heat conduction  

E-Print Network (OSTI)

We study the Brownian momentum process, a model of heat conduction, weakly coupled to heat baths. In two different settings of weak coupling to the heat baths, we study the non-equilibrium steady state and its proximity to the local equilibrium measure in terms of the strength of coupling. For three and four site systems, we obtain the two-point correlation function and show it is generically not multilinear.

Redig, Frank

2011-01-01T23:59:59.000Z

131

Aging of a Homogeneously Quenched Colloidal Glass-forming Liquid  

E-Print Network (OSTI)

The non-equilibrium self-consistent generalized Langevin equation theory of colloid dynamics is used to describe the non-stationary aging processes occurring in a suddenly quenched model colloidal liquid with hard-sphere plus short-ranged attractive interactions, whose static structure factor and van Hove function evolve irreversibly from the initial conditions before the quench to a final, dynamically arrested state. The comparison of our numerical results with available simulation data are highly encouraging.

Pedro Ramrez-Gonzlez; Magdaleno Medina-Noyola

2010-11-17T23:59:59.000Z

132

Research | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Research Research Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Basic Research Needs Grand Challenges Science Highlights News & Events Publications Contact BES Home Research Print Text Size: A A A RSS Feeds FeedbackShare Page The 46 EFRC awards span the full range of energy research challenges described in the BES Basic Research Needs (BRN) series of workshop reports while also addressing one or more of the science grand challenges described in the BESAC report, Directing Matter and Energy: Five Challenge for Science and the Imagination (see below). Many of the EFRCs address multiple energy challenges that are linked by common scientific themes, such as interfacial chemistry for solar energy conversion and electrical energy storage or rational design of materials for multiple potential energy

133

EFRC: Administration and Operation  

NLE Websites -- All DOE Office Websites (Extended Search)

Mark Pederson PhD Computation and Theoretical Chemistry Office of Basic Energy Sciences Office of Science, U.S. Department of Energy Computing and Storage Requirements for Basic Energy Sciences An ASCR / BES / NERSC Workshop February 9-10, 2010 9AM OFFICE OF SCIENCE OFFICE OF SCIENCE Primary: Near Future Needs of Capacity Computing? BES has approximately 150 users requesting 50K to 4M processor hours (PU) per year. BES users use approximately 80-100M PU per year through the NERSC allocation process NERSC users span the BES core research areas, the energy frontier research centers and the "Basic Research Needs (BRN)" workshops. Role/Needs of Capacity vs Capability? OFFICE OF SCIENCE Energy and Science Grand Challenges http://www.sc.doe.gov/bes/reports/list.html

134

CI-ON Ex A (Rev. 0.2, 6/14/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

2, 6/14/13) Exhibit A General Conditions 2, 6/14/13) Exhibit A General Conditions Page 1 of 12 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-A1 COMMERCIAL ITEMS (Mar 2012)............................................................................................ 2 GC-1B DEFINITIONS (Mar 2012) ......................................................................................................... 4 GC-2B CORRESPONDENCE AND SUBCONTRACT INTERPRETATION (Jan 2010) ....................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ........................................................................................... 4 GC-6A ORDER OF PRECEDENCE (Jan 2010) ................................................................................... 5 GC-11 NEW MEXICO GROSS RECEIPTS TAX (Jun 2009)................................................................ 5

135

CI-ON Ex A (Rev. 0.1, 4/9/13) Exhibit A General Conditions  

NLE Websites -- All DOE Office Websites (Extended Search)

1, 4/9/13) Exhibit A General Conditions 1, 4/9/13) Exhibit A General Conditions Page 1 of 24 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-A1 COMMERCIAL ITEMS (Mar 2012)............................................................................................ 2 GC-1B DEFINITIONS (Mar 2012) ......................................................................................................... 4 GC-2B CORRESPONDENCE AND SUBCONTRACT INTERPRETATION (Jan 2010) ....................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ........................................................................................... 4 GC-6A ORDER OF PRECEDENCE (Jan 2010) ................................................................................... 5 GC-11 NEW MEXICO GROSS RECEIPTS TAX (Jun 2009)................................................................ 5

136

CI-ON Exhibit A General Conditions (Rev 0.3, 9-27-13)  

NLE Websites -- All DOE Office Websites (Extended Search)

3, 9/27/13) Exhibit A General Conditions 3, 9/27/13) Exhibit A General Conditions Page 1 of 12 EXHIBIT "A" GENERAL CONDITIONS TABLE OF CONTENTS GC Title Page GC-A1 COMMERCIAL ITEMS (Mar 2012) ........................................................................................... 2 GC-1B DEFINITIONS (Mar 2012) ......................................................................................................... 4 GC-2B CORRESPONDENCE AND SUBCONTRACT INTERPRETATION (Jan 2010) ....................... 4 GC-5 NOTICE TO PROCEED (Jul 2011) ........................................................................................... 4 GC-6A ORDER OF PRECEDENCE (Jan 2010) ................................................................................... 5 GC-11 NEW MEXICO GROSS RECEIPTS TAX (Jun 2009) ................................................................ 5

137

Particle production in matter at extreme conditions  

E-Print Network (OSTI)

We study particle production and its density evolution and equilibration in hot dense medium. One type of hot dense medium, which we study, is hadronic gas produced at quark gluon plasma hadronization in heavy ions collisions in SPS, RHIC and LHC experiments. We study hadron production at non-equilibrium quark gluon plasma hadronization and their evolution in thermal hadronic gas phase. We use non-equilibrium hadronization as the initial condition in the study of hadronic kinetic phase. During this time period some hadronic resonances can be produced in lighter hadrons fusion. Production of resonances is dominant over decay if there is non-equilibrium excess of decay products. Within this model we explain apparently contradictory experimental results reported in RHIC experiments: Sigma(1385) yield is enhanced while Lambda(1520) yield is suppressed compared to the statistical hadronization model expectation obtained without kinetic phase. We also predict Delta(1232) enhancement. The second type of plasma medium we consider is the relativistic electron positron photon plasma drop. This plasma is expected to be produced in decay of supercritical field created in ultrashort laser pulse. We study at what conditions this plasma drop is opaque for photons and therefore may reach thermal and chemical equilibrium. Further we consider muon and pion production in this plasma also as a diagnostic tool. Finally all these theoretical developments can be applied to begin a study of particles evolution in early universe in temperatures domain from QGP hadronization (160 MeV) to nucleosynthesis (0.1 MeV). The first results on pion equilibration are presented here.

Inga Kuznetsova

2009-09-02T23:59:59.000Z

138

Soft Modes, Resonances and Quantum Transport  

E-Print Network (OSTI)

Effects of the propagation of particles, which have a finite life-time and an according width in their mass spectrum, are discussed in the context of transport description. First, the importance of coherence effects (Landau-Pomeranchuk-Migdal effect) on production and absorption of field quanta in non-equilibrium dense matter is considered. It is shown that classical diffusion and Langevin results correspond to re-summation of certain field-theory diagrams formulated in terms of full non-equilibrium Green's functions. Then the general properties of broad resonances in dense and hot systems are discussed in the framework of a self-consistent and conserving Phi-derivable method of Baym at the examples of the rho-meson in hadronic matter and the pion in dilute nuclear matter. Further we address the problem of a transport description that properly accounts for the damping width of the particles. The Phi-derivable method generalized to the real-time contour provides a self-consistent and conserving kinetic scheme. We derive a generalized expression for the non-equilibrium kinetic entropy flow, which includes corrections from fluctuations and mass-width effects. In special cases an H-theorem is proved. Memory effects in collision terms give contributions to the kinetic entropy flow that in the Fermi-liquid case recover the famous bosonic type T^3 ln T correction to the specific heat of liquid Helium-3. At the example of the pion-condensate phase transition in dense nuclear matter we demonstrate important part played by the width effects within the quantum transport.

Yu. B. Ivanov; J. Knoll; H. van Hees; D. N. Voskresensky

2000-05-31T23:59:59.000Z

139

NERC | U.S. DOE Office of Science (SC)  

NLE Websites -- All DOE Office Websites (Extended Search)

NERC NERC Energy Frontier Research Centers (EFRCs) EFRCs Home Centers Research Science Highlights News & Events Publications Contact BES Home Centers NERC Print Text Size: A A A RSS Feeds FeedbackShare Page Non-equilibrium Energy Research Center (NERC) Director(s): Bartosz A. Grzybowski Lead Institution: Northwestern University Mission: To understand self-organization in dissipative, far-from-equilibrium systems and to use this knowledge to synthesize adaptive, reconfigurable materials for energy storage and transduction. Research Topics: catalysis (homogeneous), catalysis (heterogeneous), thermal conductivity, thermoelectric, bio-inspired, energy storage (including batteries and capacitors), superconductivity, mechanical behavior, charge transport, materials and chemistry by design, synthesis (novel materials), synthesis

140

Nonequilibrium mesoscopic superconductors in a fluctuational regime.  

SciTech Connect

We develop a non-equilibrium Ginzburg-Landau-type theory of the far-from-equilibrium dynamics of superconductors in a fluctuational regime and apply our approach to quantitative description of a superconductor island in a stationary nonequilibrium state. We derive the effective temperature of the nonequilibrium state and find fluctuational contributions to the magnetic susceptibility showing that it becomes a singular function of {radical}V-V{sub c}, where V is the external drive and V{sub c} is its 'critical' value at which the nonequilibrium phase transition takes place.

Chtchelkatchev, N.; Vinokur, V.; Materials Science Division; Moscow Inst. of Physics and Technology

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

The maximum energy dissipation principle and phenomenological cooperative and collective effects  

E-Print Network (OSTI)

The collective phenomena in physics and cooperative phenomena in biology/chemistry is compared in terms of the variational description. The maximum energy dissipation principle is employed and the cost-like functional is chosen according to an optimal control based formulation (Moroz, 2008; Moroz, 2009). Using this approach, the variational outline has been considered for non-equilibrium thermodynamic conditions. The differences between the application of the proposed approach to the description of cooperative phenomena in chemical/biochemical kinetics and the Landau free energy approach to collective phenomena in physics have been investigated.

Moroz, Adam

2010-01-01T23:59:59.000Z

142

Validation of IVA Computer Code for Flow Boiling Stability Analysis  

SciTech Connect

IVA is a computer code for modeling of transient multiphase, multi-component, non-equilibrium flows in arbitrary geometry including flow boiling in 3D nuclear reactors. This work presents part of the verification procedure of the code. We analyze the stability of flow boiling in natural circulation loop. Experimental results collected on the AREVA/FANP KATHY loop regarding frequencies, mass flows and decay ratio of the oscillations are used for comparison. The comparison demonstrates the capability of the code to successfully simulate such class of processes. (author)

Ivanov Kolev, Nikolay [Framatome-ANP, PO Box 3220, D-91058, Erlangen (Germany)

2006-07-01T23:59:59.000Z

143

Heat conduction in 2D strongly-coupled dusty plasmas  

E-Print Network (OSTI)

We perform non-equilibrium simulations to study heat conduction in two-dimensional strongly coupled dusty plasmas. Temperature gradients are established by heating one part of the otherwise equilibrium system to a higher temperature. Heat conductivity is measured directly from the stationary temperature profile and heat flux. Particular attention is paid to the influence of damping effect on the heat conduction. It is found that the heat conductivity increases with the decrease of the damping rate, while its magnitude confirms previous experimental measurement.

Hou, Lu-Jing

2008-01-01T23:59:59.000Z

144

Experimental evidence for the separability of compound-nucleus and fragment properties in fission  

E-Print Network (OSTI)

The large body of experimental data on nuclear fission is analyzed with a semi-empirical ordering scheme based on the macro-microscopic approach and the separability of compound-nucleus and fragment properties on the fission path. We apply the statistical model to the non-equilibrium descent from saddle to scission, taking the influence of dynamics into account by an early freeze out. The present approach reveals a large portion of common features behind the variety of the complex observations made for the different systems. General implications for out-of-equilibrium processes are mentioned.

Karl-Heinz Schmidt; Aleksandra Kelic; Maria Valentina Ricciardi

2007-11-26T23:59:59.000Z

145

Duality, thermodynamics, and the linear programming problem in constraint-based models of metabolism  

E-Print Network (OSTI)

It is shown that the dual to the linear programming problem that arises in constraint-based models of metabolism can be given a thermodynamic interpretation in which the shadow prices are chemical potential analogues, and the objective is to minimise free energy consumption given a free energy drain corresponding to growth. The interpretation is distinct from conventional non-equilibrium thermodynamics, although it does satisfy a minimum entropy production principle. It can be used to motivate extensions of constraint-based modelling, for example to microbial ecosystems.

Patrick B. Warren; Janette L. Jones

2007-02-09T23:59:59.000Z

146

NONEQUILIBRIUM FLUCTUATIONS IN SHOCK COMPRESSION OF POLYCRYSTALLINE ALPHA-IRON  

Science Conference Proceedings (OSTI)

We report a numerical study of heterogeneous and nonequilibrium fluctuations in shock compression of {alpha}-iron at the grain level. A quasi-molecular code called DM2 is used to model the interactions of a plane shock wave with grain boundaries and crystal anisotropy over the pressure range of 5-45 GPa. Highly transient eddies that were reported earlier are again observed. We show new features through an elementary statistical analysis. They are (1) a characteristic decay constant for the non-equilibrium fluctuation on the order of 20ns, (2) a resonance phenomenon at an intermediate shock pressure, and (3) a more uniform shock structure for very high pressures.

Y. HORIE; K. YANO

2001-06-01T23:59:59.000Z

147

QCD plasma instability and thermalisation at heavy ion collisions  

E-Print Network (OSTI)

Under suitable non-equilibrium conditions QCD plasma can develop plasma instabilities, where some modes of the plasma grow exponentially. It has been argued that these instabilities can play a significant role in the thermalisation of the plasma in heavy-ion collision experiments. We study the instability in SU(2) plasmas using the hard thermal loop effective lattice theory, which is suitable for studying real-time evolution of long wavelength modes in the plasma. We observe that under suitable conditions the plasma can indeed develop an instability which can grow to a very large magnitude, necessary for the rapid thermalisation in heavy-ion collisions.

Dietrich Bodeker; Kari Rummukainen

2007-11-13T23:59:59.000Z

148

Hadron production and QGP Hadronization in Pb--Pb collisions at $\\sqrt{s_{NN}}=2.76$ TeV  

E-Print Network (OSTI)

We show that all central rapidity hadron yields measured in Pb--Pb collisions at $\\sqrt{s_{NN}}=2.76$ TeV are well described by the chemical non-equilibrium statistical hadronization model (SHM), where the chemically equilibrated QGP source breaks up directly into hadrons. SHM parameters are obtained as a function of centrality of colliding ions, and we compare CERN Large Hadron Collider (LHC) with Brookhaven National Laboratory Relativistic Heavy Ion Collider (RHIC) results. We predict yields of unobserved hadrons and address anti-matter production. The physical properties of the quark--gluon plasma fireball particle source show universality of hadronization conditions at LHC and RHIC.

Michal Petran; Jean Letessier; Vojtech Petracek; Johann Rafelski

2013-03-08T23:59:59.000Z

149

Comparative Study of Ultimate Saturation Velocity in Zigzag and Chiral Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Charge transfer mechanism in carbon nanotubes (CNTs) from the scattering-limited Ohmic transport to high-field-initiated ballistic transport is studied. It is shown that the electrons changes their motion from randomness (in equilibrium) to streamlined one (in non-equilibrium) when high electric field is applied. The intrinsic velocity is discussed in non-parabolic semiconducting limits considering the nondegenerate and degenerate situations. The results obtained are significant in extracting carrier transport properties from experimental data on CNTs and in understanding the fundamental processes controlling the charge transport in nanoscale devices.

Chek, Desmond C. Y.; Hashim, Abdul Manaf [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Tan, Michael Loong Peng [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Arora, Vijay K. [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA 18766 (United States)

2011-05-25T23:59:59.000Z

150

Method and apparatus for chemically altering fluids in continuous flow  

DOE Patents (OSTI)

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation. 4 figures.

Heath, W.O.; Virden, J.W. Jr.; Richardson, R.L.; Bergsman, T.M.

1993-10-19T23:59:59.000Z

151

Method and apparatus for chemically altering fluids in continuous flow  

DOE Patents (OSTI)

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation.

Heath, William O. (Richland, WA); Virden, Jr., Judson W. (Richland, WA); Richardson, R. L. (West Richland, WA); Bergsman, Theresa M. (Richland, WA)

1993-01-01T23:59:59.000Z

152

An Exact Calculation of Electron-Ion Energy Splitting in a Hot Plasma  

SciTech Connect

In this brief report, I summarize the rather involved recent work of Brown, Preston, and Singleton (BPS). In Refs. [2] and [3], BPS calculate the energy partition into ions and electrons as a charged particle traverses a non-equilibrium two-temperature plasma. These results are exact to leading and next-to-leading order in the plasma coupling g, and are therefore extremely accurate in a weakly coupled plasma. The new BPS calculations are compared with the more standard work of Fraley et al. [12]. The results differ substantially at higher temperature when T{sub I} {ne} T{sub e}.

Singleton, Robert L [Los Alamos National Laboratory

2012-09-10T23:59:59.000Z

153

The many-body Green function of degenerate systems  

E-Print Network (OSTI)

A rigorous non perturbative adiabatic approximation of the evolution operator in the many-body physics of degenerate systems is derived. This approximation is used to solve the long-standing problem of the choice of the initial states of H0 leading to eigenstates of H0+V for degenerate systems. These initial states are eigenstates of P0 V P0, where P0 is the projection onto a degenerate eigenspace of H0. This result is used to give the proper definition of the Green function, the statistical Green function and the non-equilibrium Green function of degenerate systems. The convergence of these Green functions is established.

Christian Brouder; Gianluca Panati; Gabriel Stoltz

2009-06-11T23:59:59.000Z

154

Macroscopic fluctuations theory of aerogel dynamics  

E-Print Network (OSTI)

We consider the thermodynamic potential describing the macroscopic fluctuation of the current and local energy of a general class of Hamiltonian models including aerogels. We argue that this potential is neither analytic nor strictly convex, a property that should be expected in general but missing from models studied in the literature. This opens the possibility of describing in terms of a thermodynamic potential non-equilibrium phase transitions in a concrete physical context. This special behaviour of the thermodynamic potential is caused by the fact that the energy current is carried by particles which may have arbitrary low speed with sufficiently large probability.

Raphael Lefevere; Mauro Mariani; Lorenzo Zambotti

2010-07-19T23:59:59.000Z

155

Coupling atomistic and continuum hydrodynamics through a mesoscopic model: application to liquid water  

E-Print Network (OSTI)

We have conducted a triple-scale simulation of liquid water by concurrently coupling atomistic, mesoscopic, and continuum models of the liquid. The presented triple-scale hydrodynamic solver for molecular liquids enables the insertion of large molecules into the atomistic domain through a mesoscopic region. We show that the triple-scale scheme is robust against the details of the mesoscopic model owing to the conservation of linear momentum by the adaptive resolution forces. Our multiscale approach is designed for molecular simulations of open domains with relatively large molecules, either in the grand canonical ensemble or under non-equilibrium conditions.

Rafael Delgado-Buscalioni; Kurt Kremer; Matej Praprotnik

2009-08-04T23:59:59.000Z

156

Probing molecular free energy landscapes by periodic loading  

E-Print Network (OSTI)

Single molecule pulling experiments provide information about interactions in biomolecules that cannot be obtained by any other method. However, the reconstruction of the molecule's free energy profile from the experimental data is still a challenge, in particular for the unstable barrier regions. We propose a new method for obtaining the full profile by introducing a periodic ramp and using Jarzynski's identity for obtaining equilibrium quantities from non-equilibrium data. Our simulated experiments show that this method delivers significant more accurate data than previous methods, under the constraint of equal experimental effort.

Oliver Braun; Andreas Hanke; Udo Seifert

2004-02-19T23:59:59.000Z

157

Tailoring electron energy distribution functions through energy confinement in dual radio-frequency driven atmospheric pressure plasmas  

SciTech Connect

A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.

O'Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)

2012-10-08T23:59:59.000Z

158

Length dependence of heat conduction in one-dimensional lattices with asymmetric inter-particle interactions  

E-Print Network (OSTI)

We have numerically studied heat conduction in a few one-dimensional momentum conserving lattices with asymmetric inter-particle interactions by the non-equilibrium heat bath method, the equilibrium Green-Kubo method, and the heat current power spectra analysis. Very strong finite-size effects are clearly observed. Such effects make the heat conduction obey a Fourier-like law in a wide regime of lattice lengths. However, in yet longer lattice lengths, the heat conductivity regains its power-law divergence. Therefore the power-law divergence of the heat conductivity in the thermodynamic limit is verified, as is expected by many existing theories.

Wang, Lei; Li, Baowen

2013-01-01T23:59:59.000Z

159

Thermodynamics of discrete quantum processes  

E-Print Network (OSTI)

We define thermodynamic configurations and identify two primitives of discrete quantum processes between configurations for which heat and work can be defined in a natural way. This allows us to uncover a general second law for any discrete trajectory that consists of a sequence of these primitives, linking both equilibrium and non-equilibrium configurations. Moreover, in the limit of a discrete trajectory that passes through an infinite number of configurations, i.e. in the reversible limit, we recover the saturation of the second law. Finally, we show that for a discrete Carnot cycle operating between four configurations one recovers Carnot's thermal efficiency.

Janet Anders; Vittorio Giovannetti

2012-11-01T23:59:59.000Z

160

Thermodynamics for individual quantum systems  

E-Print Network (OSTI)

We present a framework for extending thermodynamics to individual quantum systems, including explicitly a thermal bath and work-storage device (essentially a 'weight' that can be raised or lowered). We then prove that the second law of thermodynamics holds in our framework, and give a simple protocol to extract the optimal amount of work from the system (equal to its change in free energy). Our results apply to any quantum system in an arbitrary initial state, in particular including non-equilibrium situations. The optimal protocol is essentially reversible, similar to classical Carnot cycles, and indeed, we can use it to construct a quantum Carnot engine.

Paul Skrzypczyk; Anthony J. Short; Sandu Popescu

2013-07-05T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Microscopic origin of the second law of thermodynamics  

E-Print Network (OSTI)

We proved when random-variable fluctuations obey the central limit theorem the equality of the uncertainty relation corresponds to the thermodynamic equilibrium state. The inequality corresponds to the thermodynamic non-equilibrium state. The uncertainty relation is a quantum-mechanics expression of the second law of thermodynamics originated in wave-particle duality. Formulas of mean square-deviations changes adjusted by random fluctuations under the minimal uncertainty relation are obtained. Finally, an assumption is made which is waiting for examination. We except phase transitions in our discussion.

You-gang Feng

2005-05-29T23:59:59.000Z

162

Pulsed Electrical Spin Injection into InGaAs Quantum Dots: Studies of the Electroluminescence Polarization Dynamics  

SciTech Connect

We present time-resolved studies of the spin polarization dynamics during and after initialization through pulsed electrical spin injection into InGaAs quantum dots embedded in a p-i-n-type spin-injection light-emitting diode. Experiments are performed with pulse widths in the nanosecond range and a time-resolved single photon counting setup is used to detect the subsequent electroluminescence. We find evidence that the achieved spin polarization shows an unexpected temporal behavior, attributed mainly to many-carrier and non-equilibrium effects in the device.

Asshoff, P.; Loeffler, W.; Fluegge, H.; Zimmer, J.; Mueller, J.; Westenfelder, B.; Hu, D. Z.; Schaadt, D. M.; Kalt, H.; Hetterich, M. [Institut fuer Angewandte Physik and DFG Center for Functional Nanostructures (CFN), Universitaet Karlsruhe, 76131 Karlsruhe (Germany)

2010-01-04T23:59:59.000Z

163

Natural time analysis of the Centennial Earthquake Catalog  

Science Conference Proceedings (OSTI)

By using the most recent version (1900-2007) of the Centennial Earthquake Catalog, we examine the properties of the global seismicity. Natural time analysis reveals that the fluctuations of the order parameter {kappa}{sub 1} of seismicity exhibit for at least three orders of magnitude a characteristic feature similar to that of the order parameter for other equilibrium or non-equilibrium critical systems-including self-organized critical systems. Moreover, we find non-trivial magnitude correlations for earthquakes of magnitude greater than or equal to 7.

Sarlis, N. V.; Christopoulos, S.-R. G. [Physics Department, Solid State Section and Solid Earth Physics Institute, University of Athens, Panepistimiopolis, Zografos 157 84, Athens (Greece)

2012-06-15T23:59:59.000Z

164

Directed transport in equilibrium : analysis of the dimer model with inertial terms  

E-Print Network (OSTI)

We have previously shown an analysis of our dimer model in the over-damped regime to show directed transport in equilibrium. Here we analyze the full model with inertial terms present to establish the same result. First we derive the Fokker-Planck equation for the system following a Galilean transformation to show that a uniformly translating equilibrium distribution is possible. Then, we find out the velocity selection for the centre of mass motion using that distribution on our model. We suggest generalization of our calculations for soft collision potentials and indicate to interesting situation with possibility of oscillatory non-equilibrium state within equilibrium.

A. Bhattacharyay

2011-08-15T23:59:59.000Z

165

Aging and Holography  

E-Print Network (OSTI)

Aging phenomena are examples of `non-equilibrium criticality' and can be exemplified by systems with Galilean and scaling symmetries but no time translation invariance. We realize aging holographically using a deformation of a non-relativistic version of gauge/gravity duality. Correlation functions of scalar operators are computed using holographic real-time techniques, and agree with field theory expectations. At least in this setup, general aging phenomena are reproduced holographically by complexifying the bulk space-time geometry, even in Lorentzian signature.

Juan I. Jottar; Robert G. Leigh; Djordje Minic; Leopoldo A. Pando Zayas

2010-04-21T23:59:59.000Z

166

Fabrication of large-area ultra-thin single crystal silicon membranes  

SciTech Connect

Perfectly, crystalline, 55 nm thick silicon membranes have been fabricated over several square millimeters and used to observe transmission ion channeling patterns showing the early evolution of the axially channeled beam angular distribution for small tilts away from the [011] axis. The reduced multiple scattering through such thin layers allows fine angular structure produced by the highly non-equilibrium transverse momentum distribution of the channeled beam during its initial propagation in the crystal to be resolved. The membrane crystallinity and flatness were measured by using proton channeling measurements and the surface roughness of 0.4 nm using atomic force microscopy.

Dang, Z. Y.; Motapothula, M.; Ow, Y. S. [Center for Ion Beam Applications, Physics Department, National University of Singapore, Lower Kent Ridge Road, Singapore 117542 (Singapore); Venkatesan, T. [NanoCore, National University of Singapore, Singapore 117576 (Singapore); Breese, M. B. H. [Center for Ion Beam Applications, Physics Department, National University of Singapore, Lower Kent Ridge Road, Singapore 117542 (Singapore); Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Rana, M. A. [Physics Division, Directorate of Science, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Osman, A. [National Centre for Physics (NCP), Shahdara Valley Road, Islamabad (Pakistan)

2011-11-28T23:59:59.000Z

167

Integration through transients for Brownian particles under steady shear  

E-Print Network (OSTI)

Abstract. Starting from the microscopic Smoluchowski equation for interacting Brownian particles under stationary shearing, exact expressions for shear dependent steadystate averages, correlation and structure functions, and susceptibilities are obtained, which take the form of generalized GreenKubo relations. They require integration of transient dynamics. Equations of motion with memory effects for transient density fluctuation functions are derived from the same microscopic starting point. We argue that the derived formal expressions provide useful starting points for approximations in order to describe the stationary nonequilibrium state of steadily sheared dense colloidal dispersions.

M. Fuchs; M. E. Cates

2005-01-01T23:59:59.000Z

168

Manipulation of Colloids by Nonequilibrium Depletion Force in Temperature Gradient  

E-Print Network (OSTI)

The non-equilibrium distribution of colloids in a polymer solution under a temperature gradient is studied experimentally. A slight increase of local temperature by a focused laser drives the colloids towards the hot region, resulting in the trapping of the colloids irrespective of their own thermophoretic properties. An amplification of the trapped colloid density with the polymer concentration is measured, and is quantitatively explained by hydrodynamic theory. The origin of the attraction is a migration of colloids driven by a non-uniform polymer distribution sustained by the polymer's thermophoresis. These results show how to control thermophoretic properties of colloids.

Hong-Ren Jiang; Hirofumi Wada; Natsuhiko Yoshinaga; Masaki Sano

2009-02-24T23:59:59.000Z

169

Disk magnetohydrodynamic power conversion system for NERVA reactor  

Science Conference Proceedings (OSTI)

The combination of a magnetohydrodynamic (MHD) generator of the disk type with a NERVA reactor yields an advanced power system particularly suited to space applications with the capability of producing up to gigawatt pulses and multi-megawatt continuous operation. Several unique features result from the combination of this type of reactor and a disk MHD generator in which hydrogen serves as the plasma working fluid. Cesium seedings is utilized under conditions which enable the generator to operate stably in the non-equilibrium electrical conduction mode. In common with all practical MHD generators, the disk output is DC and voltages in the range 20--100 kV are attainable. This leads to a simplification of the power conditioning system and a major reduction in specific mass. Taken together with the high performance capabilities of the NERVA reactor, the result is an attractively low overall system specific mass. Further, the use of non-equilibrium ionization enables system specific enthalpy extractions in excess of 40% to be attained. This paper reports the results of a study to establish the basis for the design of a cesium seeded hydrogen MHD disk generator. Generator performance results are presented in terms of a stability factor which is related to cesium seeded hydrogen plasma behavior. It is shown that application of the results already obtained with cesium seeded noble gases (argon and helium) to the case of hydrogen as the working fluid in a disk MHD generator enables a high performance power system to be defined.

Jackson, W.D. (HMJ Corporation. 10400 Connecticut Ave., Kensington, Maryland 20895 (United States)); Bernard, F.E. (Westinghouse Corp., P.O. Box 355, Pittsburgh, Pennsylvania 15230 (United States)); Holman, R.R. (HMJ Corporation, 10400 Connecticut Ave., Kensington, Maryland 20895 (United States)); Maxwell, C.D. (STD Research Corp., P.O. Box C, Arcadia, California 91006 (United States)); Seikel, G.R. (SeiTec, Inc., P.O. Box 81264, Cleveland, Ohio 44181 (United States))

1993-01-15T23:59:59.000Z

170

On the minimum temperature of the quiet solar chromosphere  

E-Print Network (OSTI)

aims: We aim to provide an estimate of the minimum temperature of the quiet solar chromosphere. methods: We perform a 2D radiation-MHD simulation spanning the upper convection zone to the lower corona. The simulation includes non-LTE radiative transfer and {an equation-of-state that includes non-equilibrium ionization of hydrogen and non-equilibrium H_2 molecule formation}. We analyze the reliability of the various assumptions made in our model in order to assess the realism of the simulation. results: Our simulation contains pockets of cool gas with down to 1660 K from 1 Mm up to 3.2 Mm height. It overestimates the radiative heating, and contains non-physical heating below 1660 K. Therefore we conclude that cool pockets in the quiet solar chromosphere might have even lower temperatures than in the simulation, provided that there exist areas in the chromosphere without significant magnetic heating. We suggest off-limb molecular spectroscopy to look for such cool pockets and 3D simulations including a local dy...

Leenaarts, Jorrit; Hansteen, Viggo; Gudiksen, Boris V

2011-01-01T23:59:59.000Z

171

High-Throughput Thin Film Approach for Screening of Temperature-Pressure-Composition Phase Space  

SciTech Connect

Many solar energy technologies, for example CIGS and CdTe photovoltaics, utilize materials in thin film form. The equilibrium phase diagrams for these and other more novel solar energy materials are not known or are irrelevant because of the non-equilibrium character of the thin film growth processes. We demonstrate a high-throughput thin film approach for screening of temperature-pressure-composition phase diagrams and phase spaces. The examples in focus are novel solar absorbers Cu-N, Cu-O and p-type transparent conductors in the Cr2O3-MnO system. The composition axis of the Cr2O3-MnO phase diagram was screened using a composition spread method. The temperature axis of the Mn-O phase diagram was screened using a temperature spread method. The pressure axes of the Cu-N and Cu-O phase diagrams were screened using rate spread method with the aid of non-equilibrium growth phenomena. Overall these three methods constitute an approach to high-throughput screening of inorganic thin film phase diagrams. This research is supported by U.S. Department of Energy as a part of two NextGen Sunshot projects and an Energy Frontier Research Center.

Zakutayev, A.; Subramaniyan, A.; Caskey, C. M.; Ndione, P. F.; Richards, R. M.; O'Hayre, R.; Ginley, D. S.

2013-01-01T23:59:59.000Z

172

Cold atmospheric pressure plasma jets: Interaction with plasmid DNA and tailored electron heating using dual-frequency excitation  

SciTech Connect

Recent progress in plasma science and technology has enabled the development of a new generation of stable cold non-equilibrium plasmas operating at ambient atmospheric pressure. This opens horizons for new plasma technologies, in particular in the emerging field of plasma medicine. These non-equilibrium plasmas are very efficient sources for energy transport through reactive neutral particles (radicals and metastables), charged particles (ions and electrons), UV radiation, and electro-magnetic fields. The effect of a cold radio frequency-driven atmospheric pressure plasma jet on plasmid DNA has been investigated. The formation of double strand breaks correlates well with the atomic oxygen density. Taken with other measurements, this indicates that neutral components in the jet are effective in inducing double strand breaks. Plasma manipulation techniques for controlled energy delivery are highly desirable. Numerical simulations are employed for detailed investigations of the electron dynamics, which determines the generation of reactive species. New concepts based on nonlinear power dissipation promise superior strategies to control energy transport for tailored technological exploitations.

Niemi, K.; O'Neill, C.; Cox, L. J.; Waskoenig, J.; Hyland, W. B.; McMahon, S. J.; Reuter, S.; Currell, F. J.; Graham, W. G.; O'Connell, D.; Gans, T. [Centre for Plasma Physics, Queen's University Belfast, Belfast BT7 1NN, Northern Ireland (United Kingdom)

2012-05-25T23:59:59.000Z

173

Kinetic phenomena in charged particle transport in gases and plasmas  

SciTech Connect

The key difference between equilibrium (thermal) and non-equilibrium (low temperature - a.k.a. cold) plasmas is in the degree in which the shape of the cross sections influences the electron energy distribution function (EEDF). In this paper we will discuss the issue of kinetic phenomena from two different angles. The first will be how to take advantage of the strong influence and use low current data to obtain the cross sections. This is also known as the swarm technique and the product of a ''swarm analysis'' is a set of cross sections giving good number, momentum and energy balances of electrons or other charged particles. At the same time understanding the EEDF is based on the cross section data. Nevertheless sometimes the knowledge of the cross sections and even the behaviour of individual particles are insufficient to explain collective behaviour of the ensemble. The resulting ''kinetic'' effects may be used to favour certain properties of non-equilibrium plasmas and even may be used as the basis of some new plasma applications.

Petrovic, Zoran Lj.; Dujko, Sasa; Sasic, Olivera; Stojanovic, Vladimir; Malovic, Gordana [Institute of Physics, University of Belgrade, POB 68 11080 Zemun (Serbia); Faculty of Traffic Engineering, University of Belgrade Belgrade (Serbia); Institute of Physics, University of Belgrade, POB 68 11080 Zemun (Serbia)

2012-05-25T23:59:59.000Z

174

The fundamental role of quantized vibrations in coherent light harvesting by cryptophyte algae  

E-Print Network (OSTI)

The influence of fast vibrations on energy transfer and conversion in natural molecular aggregates is an issue of central interest. This article shows the important role of high-energy quantized vibrations and their non-equilibrium dynamics for energy transfer in photosynthetic systems with highly localized excitonic states. We consider the cryptophyte antennae protein phycoerythrin 545 and show that coupling to quantized vibrations which are quasi-resonant with excitonic transitions is fundamental for biological function as it generates non-cascaded transport with rapid and wider spatial distribution of excitation energy. Our work also indicates that the non-equilibrium dynamics of such vibrations can manifest itself in ultrafast beating of both excitonic populations and coherences at room temperature, with time scales in agreement with those reported in experiments. Moreover, we show that mechanisms supporting coherent excitonic dynamics assist coupling to selected modes that channel energy to preferential sites in the complex. We therefore argue that, in the presence of strong coupling between electronic excitations and quantized vibrations, a concrete and important advantage of quantum coherent dynamics is precisely to tune resonances that promote fast and effective energy distribution.

Avinash Kolli; Edward J. O'Reilly; Gregory D. Scholes; Alexandra Olaya-Castro

2012-03-20T23:59:59.000Z

175

A reaction-based river/stream water quality model Part I: Model development and numerical schemes  

SciTech Connect

This paper presents the conceptual and mathematical development of a numerical model of sediment and reactive chemical transport in river/streams. The distribution of mobile suspended sediments and immobile bed sediments is controlled by hydrologic transport as well as erosion and deposition processes. The fate and transport of water quality constituents involving a variety of chemical and physical processes is mathematically described by a system of reaction equations for immobile constituents and advective-dispersive-reactive transport equations for constituents. To circumvent stiffness associated with equilibrium reactions, matrix decomposition is performed via Gauss-Jordan column reduction. After matrix decomposition, the system of water quality constituent reactive transport equations is transformed into a set of thermodynamic equations representing equilibrium reactions and a set of transport equations involving no equilibrium reactions. The decoupling of equilibrium and kinetic reactions enables robust numerical integration of the partial differential equations for non-equilibrium-variables. Solving non-equilibrium-variable transport equations instead of individual water quality constituent transport equations also reduces the number of PDEs. A variety of numerical methods are investigated for solving the mixed differential and algebraic equations. Two verification examples are compared with analytical solutions to demonstrate the correctness of the code and to illustrate the importance of employing application-dependent numerical methods to solve specific problems.

Zhang, Fan [ORNL; Gour-Tsyh, Yeh [University of Central Florida, Orlando; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Jardine, Philip M [ORNL

2008-01-01T23:59:59.000Z

176

Modeling Degradation in Solid Oxide Electrolysis Cells - Volume II  

DOE Green Energy (OSTI)

Idaho National Laboratory has an ongoing project to generate hydrogen from steam using solid oxide electrolysis cells (SOECs). To accomplish this, technical and degradation issues associated with the SOECs will need to be addressed. This report covers various approaches being pursued to model degradation issues in SOECs. An electrochemical model for degradation of SOECs is presented. The model is based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. It is shown that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential,, within the electrolyte. The within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just near the oxygen electrode/electrolyte interface, leading to oxygen electrode delamination. These predictions are in accordance with the reported literature on the subject. Development of high pressures may be avoided by introducing some electronic conduction in the electrolyte. By combining equilibrium thermodynamics, non-equilibrium (diffusion) modeling, and first-principles, atomic scale calculations were performed to understand the degradation mechanisms and provide practical recommendations on how to inhibit and/or completely mitigate them.

Manohar Motwani

2011-09-01T23:59:59.000Z

177

Kubo formulas for relativistic fluids in strong magnetic fields  

SciTech Connect

Magnetohydrodynamics of strongly magnetized relativistic fluids is derived in the ideal and dissipative cases, taking into account the breaking of spatial symmetries by a quantizing magnetic field. A complete set of transport coefficients, consistent with the Curie and Onsager principles, is derived for thermal conduction, as well as shear and bulk viscosities. It is shown that in the most general case the dissipative function contains five shear viscosities, two bulk viscosities, and three thermal conductivity coefficients. We use Zubarev's non-equilibrium statistical operator method to relate these transport coefficients to correlation functions of the equilibrium theory. The desired relations emerge at linear order in the expansion of the non-equilibrium statistical operator with respect to the gradients of relevant statistical parameters (temperature, chemical potential, and velocity.) The transport coefficients are cast in a form that can be conveniently computed using equilibrium (imaginary-time) infrared Green's functions defined with respect to the equilibrium statistical operator. - Highlights: > Strong magnetic fields can make charged fluids behave anisotropically. > Magnetohydrodynamics for these fluids contains 5 shear, 2 bulk viscosities, and 3 heat conductivities. > We derive Kubo formulas for these transport coefficients.

Huang Xuguang, E-mail: xhuang@th.physik.uni-frankfurt.de [Institute for Theoretical Physics, J. W. Goethe-Universitaet, D-60438 Frankfurt am Main (Germany); Sedrakian, Armen [Institute for Theoretical Physics, J. W. Goethe-Universitaet, D-60438 Frankfurt am Main (Germany); Rischke, Dirk H. [Institute for Theoretical Physics, J. W. Goethe-Universitaet, D-60438 Frankfurt am Main (Germany); Frankfurt Institute for Advanced Studies, D-60438 Frankfurt am Main (Germany)

2011-12-15T23:59:59.000Z

178

Influence of cooling rate on the development of multiple generations of {gamma}' precipitates in a commercial nickel base superalloy  

Science Conference Proceedings (OSTI)

The compositional and microstructural evolution of different generations of {gamma}' precipitates during the continuous cooling of a commercial nickel base superalloy, Rene88DT, has been characterized by three dimensional atom probe tomography coupled with energy-filtered transmission electron microscopy studies. After solutionizing in the single {gamma} phase field, continuous cooling at a very high rate results in a monomodal size distribution of {gamma}' precipitates with a high nucleation density and non-equilibrium compositions. In contrast, a relatively slower cooling rate ({approx} 24 deg. C/min) results in a multi-modal size distribution of {gamma}' precipitates with the larger first generation primary precipitates exhibiting close to equilibrium composition, along with the smaller scale secondary {gamma}' precipitates, exhibiting non-equilibrium composition (excess of Co and Cr, depleted in Al and Ti). The composition of the {gamma} matrix near these precipitates also exhibits similar trends with the composition being closer to equilibrium near the primary precipitates as compared to the secondary precipitates. - Highlights: {yields} Effect of cooling rate on the precipitation of {gamma}' particles in commercial nickel base superalloy. {yields} Couples EFTEM and 3DAP studies to determine the composition and morphology of {gamma}' precipitates. {yields} Determination of near and far field compositional variations within the gamma matrix leading to subsequent precipitation.

Singh, A.R.P. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Nag, S., E-mail: nag.soumya@gmail.com [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Hwang, J.Y. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States); Viswanathan, G.B.; Tiley, J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Dayton, OH (United States); Srinivasan, R. [ExxonMobil Research and Engineering Company, Annandale, NJ (United States); Fraser, H.L. [Center for the Accelerated Maturation of Materials and Department of Materials Science and Engineering, The Ohio State University, Columbus, OH (United States); Banerjee, R. [Center for Advanced Research and Technology and Department of Materials Science and Engineering, University of North Texas, Denton, TX (United States)

2011-09-15T23:59:59.000Z

179

Laser-assisted scanning probe alloying nanolithography (LASPAN) and its application in gold-silicon system  

E-Print Network (OSTI)

Nanoscale science and technology demand novel approaches and new knowledge to further advance. Nanoscale fabrication has been widely employed in both modern science and engineering. Micro/nano lithography is the most common technique to deposit nanostructures. Fundamental research is also being conducted to investigate structural, physical and chemical properties of the nanostructures. This research contributes fundamental understanding in surface science through development of a new methodology. Doing so, experimental approaches combined with energy analysis were carried out. A delicate hardware system was designed and constructed to realize the nanometer scale lithography. We developed a complete process, namely laser-assisted scanning probe alloying nanolithography (LASPAN), to fabricate well-defined nanostructures in gold-silicon (Au-Si) system. As a result, four aspects of nanostructures were made through different experimental trials. A non-equilibrium phase (AuSi3) was discovered, along with a non-equilibrium phase diagram. Energy dissipation and mechanism of nanocrystalization in the process have been extensively discussed. The mechanical energy input and laser radiation induced thermal energy input were estimated. An energy model was derived to represent the whole process of LASPAN.

Peng, Luohan

2008-08-01T23:59:59.000Z

180

Kenneth Gray - Argonne National Laboratories, Materials Sicence Division  

NLE Websites -- All DOE Office Websites (Extended Search)

EM > Kenneth Gray EM > Kenneth Gray Kenneth Gray Group Leader, Sr. Physicist Bldg. 223, A-125 Phone: 630-252-9595 This e-mail address is being protected from spambots. You need JavaScript enabled to view it. Biography Kenneth E. Gray is a Senior Scientist in the Materials Science Division. His experimental thesis involved tunneling studies of superconductors and non-equilibrium effects. He joined Argonne's superconductivity group as a post-doc, and in 1972 became a staff member specializing in non-equilibrium effects in superconductors. He is presently the group leader of the Emerging Materials Group. He was the Director for the NATO Advanced Study Institute "Nonequilibrium Superconductivity, Phonons and Kapitza Boundaries" Maratea, Italy, August 25-September 5, 1980 and Chairman of the "1992 Applied Superconductivity Conference" Chicago, Illinois, August 23-28, 1992. He was the Thin Film Research Area Coordinator for the NSF Science and Technology Center for Superconductivity (University of Illinois, Urbana), Feb. 1989-Jan. 1992. He edited Nonequilibrium Superconductivity, Phonons and Kapitza Boundaries, (Plenum Publishing Corporation, 1981). He holds 5 patents, and Research and Development Magazine recognized two of his inventions as among the 100 most significant technical products of their year. These are the Superconducting Tunnel Junction Transistor in 1979 and the 3He/4He Dilution Refrigerator (with P. Roach) in 1988. He received the 1989 Significant Implication for Department of Energy Related Technologies in Solid State Physics - "Thin-Film Superconducting Device Concepts and Development". He has co-authored 250 publications (5300 citations) and is known for research collaborations on flux dynamics and point-contact tunneling in high-temperature superconductors and transport measurements in the highly anisotropic colossal magnetoresistive layered manganites. He is a Senior Scientist and the Group Leader for the Emerging Materials Group at Argonne. His current research interests include tunneling in exotic superconductors, phase diagrams of layered manganites and non-equilibrium effects in complex electronic oxides. He was also an integral part of the recent development of a compact solid-state source for THz radiation.

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Numerical Investigation of Fractured Reservoir Response to Injection/Extraction Using a Fully Coupled Displacement Discontinuity Method  

E-Print Network (OSTI)

In geothermal reservoirs and unconventional gas reservoirs with very low matrix permeability, fractures are the main routes of fluid flow and heat transport, so the fracture permeability change is important. In fact, reservoir development under this circumstance relies on generation and stimulation of a fracture network. This thesis presents numerical simulation of the response of a fractured rock to injection and extraction considering the role of poro-thermoelasticity and joint deformation. Fluid flow and heat transport in the fracture are treated using a finite difference method while the fracture and rock matrix deformation are determined using the displacement discontinuity method (DDM). The fractures response to fluid injection and extraction is affected both by the induced stresses as well as by the initial far-field stress. The latter is accounted for using the non-equilibrium condition, i.e., relaxing the assumption that the rock joints are in equilibrium with the in-situ stress state. The fully coupled DDM simulation has been used to carry out several case studies to model the fracture response under different injection/extractions, in-situ stresses, joint geometries and properties, for both equilibrium and non-equilibrium conditions. The following observations are made: i) Fluid injection increases the pressure causing the joint to open. For non-isothermal injection, cooling increases the fracture aperture drastically by inducing tensile stresses. Higher fracture aperture means higher conductivity. ii) In a single fracture under constant anisotropic in-situ stress (non-equilibrium condition), permanent shear slip is encountered on all fracture segments when the shear strength is overcome by shear stress in response to fluid injection. With cooling operation, the fracture segments in the vicinity of the injection point are opened due to cooling-induced tensile stress and injection pressure, and all the fracture segments experience slip. iii) Fluid pressure in fractures increases in response to compression. The fluid compressibility and joint stiffness play a role. iv) When there are injection and extraction in fractured reservoirs, the cooler fluid flows through the fracture channels from the injection point to extraction well extracting heat from the warmer reservoir matrix. As the matrix cools, the resulting thermal stress increases the fracture apertures and thus increases the fracture conductivity. v) Injection decreases the amount of effective stress due to pressure increase in fracture and matrix near a well. In contrast, extraction increases the amount of effective stress due to pressure drop in fracture and matrix.

Lee, Byungtark

2011-08-01T23:59:59.000Z

182

U.S. Department of Energy Categorical Exclusion Determination Form  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Agency - Agency - Energy Pro-iectTitle: 0289-1600 Sheetak - Non-EquilibriumAsymmetric Thermoelectric Devices Location: Tennessee Proposed Action or Project Description: American Recovery and Reinvestment Act: Funding will support bench-scale research proposed work is consistent with the goals save energy and reduce GHG emissions. and development on a novel thermoelectric device for use in various air conditioning applications. The of BEETIT: the development of energy efficient cooling technologies and air conditioners for buildings, to Proposed work consists entirely of RD&D work to be completed in Sheetak's facilities in Austin, TX and the National Nanotechnology Infrastructure Network on the campus of the University of Texas - Austin in Austin, TX. The work performed will be limited

183

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Recovery from Recovery from Hydrate-bearing Sediments Prime Recipients J. Carlos Santamarina Georgia Tech Costas Tsouris ORNL/Georgia Tech Carolyn Ruppel USGS (no cost) Agreement Number DE-PS26-06NT42820 NETL Project Manager Timothy Grant Methane Hydrates Kick-Off Meeting Objective - Expected Benefits Hydrates * Seafloor instability [gigaton] [USGS] [Kvenvolden and Lorenson, 2001; www.pet.hw.ac.uk; Ballough et al.)] * Energy resource * Climate change: green house effect Challenge Methane production from hydrate-bearing sediments Understanding Prediction * Sediment properties * Hydrate formation history * Phases/fluids fronts * Effects of driving forces * Thermodynamics in confinement * Non-equilibrium analysis * Kinetics in confinement * Multiphase transport Keys: Energy Forms + Scales + Sediment

184

Albany, OR * Anchorage, AK * Morgantown, WV * Pittsburgh, PA * Sugar Land, TX  

NLE Websites -- All DOE Office Websites (Extended Search)

Rodosta Rodosta Carbon Storage Technology Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507 304-285-1345 traci.rodosta@netl.doe.gov Darin Damiani Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507 304-285-4398 darin.damiani@netl.doe.gov Vivak Malhotra Principal Investigator Southern Illinois University Neckers 483A Mailcode: 4401 Carbondale, IL 62901 618-453-2643 Fax: 618-453-1056 vmalhotra@physics.siu.edu PARTNERS None Risk Assessment and Monitoring of Stored CO2 in Organic Rock under Non-Equilibrium Conditions Background Fundamental and applied research on carbon capture, utilization and storage (CCUS)

185

Science for the Future of RHIC  

NLE Websites -- All DOE Office Websites (Extended Search)

77334-2006-IR 77334-2006-IR Future Science at the Relativistic Heavy Ion Collider December 30, 2006 Summary of the 2004 - 2005 RHIC II Science Working Groups 1 2 Table of contents 1. Overview 4 2. Summary of the first 5 years at RHIC 9 2..1. Heavy ion physics 9 2..2. Spin physics 18 3. The RHIC facility - evolution and future 22 4. Fundamental questions for the next ten years at RHIC 25 4.1. What are the phases of QCD matter? 25 4.2. What is the wave function of a heavy nucleus. 26 4.3. What is the wave function of the proton? 26 4.4. What is the nature of non-equilibrium processes in a fundamental theory? 27 5. The future physics program at RHIC 28 5.1. Equation of state and the QCD phase diagram 29 5.1.1. Dynamical considerations 29

186

Marius Stan | Argonne National Laboratory  

NLE Websites -- All DOE Office Websites (Extended Search)

Marius Stan Senior Scientist - Nuclear Engineering Dr. Marius Stan is a physicist and a chemist interested in non-equilibrium thermodynamics, heterogeneity, and multi-scale computational science for energy applications. He came to Argonne and the University of Chicago in 2010, from Los Alamos National Laboratory. Marius is a Senior Fellow at the University of Chicago's Computation Institute. The goal of his research is to discover or design materials, structures, and device architectures for nuclear energy and energy storage. To that end, Marius develops theory-based (as opposite to empirical) mathematical models of thermomechanical and chemical properties of imperfect materials. The imperfection comes from defects or deviations from stoichiometry (e.g.,

187

Project Title  

NLE Websites -- All DOE Office Websites (Extended Search)

RISK ASSESSMENT AND MONITORING OF RISK ASSESSMENT AND MONITORING OF STORED CO 2 IN ORGANIC ROCKS UNDER NON- EQUILIBRIUM CONDITIONS DOE (NETL) Award Number: DE-FE0002423 Investigator: Vivak (Vik) Malhotra DOE supported undergraduate student participants: Jacob Huffstutler, Ryan Belscamper, Stephen Hofer, Kyle Flannery,, Bradley Wilson, Jamie Pfister, Jeffrey Pieper, Joshua T. Thompson, Collier Scalzitti-Sanders, and Shaun Wolfe Southern Illinois University-Carbondale Carbondale, Illinois 62901-4401 U.S. Department of Energy National Energy Technology Laboratory Carbon Storage R&D Project Review Meeting Developing the Technologies and Building the Infrastructure for CO 2 Storage August 21-23, 2012 2 Benefit to the Carbon Storage Program * Program goals being addressed: - To attempt to answer whether CO

188

Page not found | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

41 - 4150 of 8,172 results. 41 - 4150 of 8,172 results. Download CX-003453: Categorical Exclusion Determination Nebraska - Tribe - Winnebago Tribe CX(s) Applied: A9, A11, B5.1 Date: 08/10/2010 Location(s): Nebraska Office(s): Energy Efficiency and Renewable Energy http://energy.gov/nepa/downloads/cx-003453-categorical-exclusion-determination Download CX-004918: Categorical Exclusion Determination Sheetak -Non-Equilibrium Asymmetric Thermoelectric Devices CX(s) Applied: B3.6 Date: 08/10/2010 Location(s): Austin, Texas Office(s): Advanced Research Projects Agency - Energy http://energy.gov/nepa/downloads/cx-004918-categorical-exclusion-determination Download CX-003176: Categorical Exclusion Determination Chicago Area Alternative Fuels Deployment Project (Summary Categorical Exclusion) CX(s) Applied: A1, A9, B3.6, B5.1

189

Физическая природа долговечности металлов в явлении динамического разрушения  

National Nuclear Security Administration (NNSA)

Materials Ejecta, Spallation and Damage Materials Ejecta, Spallation and Damage Physical Nature of Metals Longevity in the Dynamic Failure Phenomenon A.Ya.Uchaev*, S.S. Sokolov*, N.I. Sel'chenkova*, E.V.Kosheleva*, and L.V. Zhabyka* * Russian Federal Nuclear Center - VNIIEF, Russia, 607188, Nizhni Novgorod region, Sarov, Mira Avenue 37 Summary: At present acute is the knowledge of time boundary of maintaining functional metal properties under extreme conditions, when the equilibrium state deviation value is comparable, for example, with phase transition energy. Results and Discussion As a rule, relaxation of strongly non-equilibrium states is accompanied by destruction processes [1], [2]. Capabilities of modern high-energy impulse scientific technology are directly associated with

190

Joint Institute for High Temperatures  

National Nuclear Security Administration (NNSA)

Joint Institute for High Temperatures of Russian Academy of Sciences Moscow Institute of Physics and Technology Extended title Extended title Excited state of warm dense matter or Exotic state of warm dense matter or Novel form of warm dense matter or New form of plasma Three sources of generation similarity: solid state density, two temperatures: electron temperature about tens eV, cold ions keep original crystallographic positions, but electron band structure and phonon dispersion are changed, transient but steady (quasi-stationary for a short time) state of non-equilibrium, uniform plasmas (no reference to non-ideality, both strongly and weakly coupled plasmas can be formed) spectral line spectra are emitted by ion cores embedded in plasma environment which influences the spectra strongly,

191

U.S. DEPARTMENT OF ENERGY - NETL CATEGORICAL EXCLUSION (CX) DESIGNATION FORM  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

23 23 V. M. Malhotra FE DE-FE0002423 Sequestration Division 10 Darin Damiani 12/01/2009 - 11/30/2012 Carbondale, Illinois Risk Assessment and Monitoring of Stored of Non-Equilibrium Conditions on CO2 Stored in Organic Rocks This project involves laboratory research at bench-scale level with the aim to understand how carbon dioxide interacts with coal and how dynamic pressure waves modulate these interactions. Darin Damiani Digitally signed by Darin Damiani DN: cn=Darin Damiani, o=NETL, ou=Sequestration Division, email=darin.damiani@netl.doe.gov, c=US Reason: I am approving this document Date: 2009.12.02 14:55:14 -05'00' 12 02 2009 john ganz Digitally signed by john ganz DN: cn=john ganz, o=NETL- DOE, ou=140 OPFC, email=john.ganz@netl.doe.gov, c=US Date: 2009.12.11 10:03:44

192

Staggered Schemes for Fluctuating Hydrodynamics  

E-Print Network (OSTI)

We develop numerical schemes for solving the isothermal compressible and incompressible equations of fluctuating hydrodynamics on a grid with staggered momenta. We develop a second-order accurate spatial discretization of the diffusive, advective and stochastic fluxes that satisfies a discrete fluctuation-dissipation balance, and construct temporal discretizations that are at least second-order accurate in time deterministically and in a weak sense. Specifically, the methods reproduce the correct equilibrium covariances of the fluctuating fields to third (compressible) and second (incompressible) order in the time step, as we verify numerically. We apply our techniques to model recent experimental measurements of giant fluctuations in diffusively mixing fluids in a micro-gravity environment [A. Vailati et. al., Nature Communications 2:290, 2011]. Numerical results for the static spectrum of non-equilibrium concentration fluctuations are in excellent agreement between the compressible and incompressible simula...

Balboa, F; Delgado-Buscalioni, R; Donev, A; Fai, T; Griffith, B; Peskin, C S

2011-01-01T23:59:59.000Z

193

Fluctuating hydrodynamics of multispecies mixtures. I. Non-reacting Flows  

E-Print Network (OSTI)

In this paper we discuss the formulation of the fluctuating Navier-Stokes (FNS) equations for multi-species, non-reactive fluids. In particular, we establish a form suitable for numerical solution of the resulting stochastic partial differential equations. An accurate and efficient numerical scheme, based on our previous methods for single species and binary mixtures, is presented and tested at equilibrium as well as for a variety of non-equilibrium problems. These include the study of giant nonequilibrium concentration fluctuations in a ternary mixture in the presence of a diffusion barrier, the triggering of a Rayleigh-Taylor instability by diffusion in a four-species mixture, as well as reverse diffusion in a ternary mixture. Good agreement with theory and experiment demonstrates that the formulation is robust and can serve as a useful tool in the study of thermal fluctuations for multi- species fluids. The extension to include chemical reactions will be treated in a sequel paper.

Balakrishnan, Kaushik; Donev, Aleksandar; Bell, John B

2013-01-01T23:59:59.000Z

194

Symmetry Relations for Trajectories of a Brownian Motor  

E-Print Network (OSTI)

A Brownian Motor is a nanoscale or molecular device that combines the effects of thermal noise, spatial or temporal asymmetry, and directionless input energy to drive directed motion. Because of the input energy, Brownian motors function away from thermodynamic equilibrium and concepts such as linear response theory, fluctuation dissipation relations, and detailed balance do not apply. The {\\em generalized} fluctuation-dissipation relation, however, states that even under strongly thermodynamically non-equilibrium conditions the ratio of the probability of a transition to the probability of the time-reverse of that transition is the exponent of the change in the internal energy of the system due to the transition. Here, we derive an extension of the generalized fluctuation dissipation theorem for a Brownian motor for the ratio between the probability for the motor to take a forward step and the probability to take a backward step.

R. Dean Astumian

2007-05-01T23:59:59.000Z

195

Survey of Morphologies Formed in the Wake of an Enslaved Phase-Separation Front in Two Dimensions  

E-Print Network (OSTI)

A phase-separation front will leave in its wake a phase-separated morphology that differs markedly from homogeneous phase-separation morphologies. For a purely diffusive system such a front, moving with constant velocity, will generate very regular, non-equilibrium structures. We present here a numerical study of these fronts using a lattice Boltzmann method. In two dimensions these structures are regular stripes or droplet arrays. In general the kind and orientation of the selected morphology and the size of the domains depends on the speed of the front as well as the composition of the material overtaken by the phase-separation front. We present a survey of morphologies as a function of these two parameters. We show that the resulting morphologies are initial condition dependent. We then examine which of the potential morphologies is the most stable. An analytical analysis for symmetrical compositions predicts the transition point from orthogonal to parallel stripes.

E. M. Foard; A. J. Wagner

2011-03-28T23:59:59.000Z

196

Stochastic Dynamical Structure (SDS) of Nonequilibrium Processes in the Absence of Detailed Balance. II: construction of SDS with nonlinear force and multiplicative noise  

E-Print Network (OSTI)

There is a whole range of emergent phenomena in non-equilibrium behaviors can be well described by a set of stochastic differential equations. Inspired by an insight gained during our study of robustness and stability in phage lambda genetic switch in modern biology, we found that there exists a classification of generic nonequilibrium processes: In the continuous description in terms of stochastic differential equations, there exists four dynamical elements: the potential function $\\phi$, the friction matrix $ S$, the anti-symmetric matrix $ T $, and the noise. The generic feature of absence of detailed balance is then precisely represented by $T$. For dynamical near a fixed point, whether or not it is stable or not, the stochastic dynamics is linear. A rather complete analysis has been carried out (Kwon, Ao, Thouless, cond-mat/0506280; PNAS, {\\bf 102} (2005) 13029), referred to as SDS I. One important and persistent question is the existence of a potential function with nonlinear force and with multiplicati...

Ao, P

2008-01-01T23:59:59.000Z

197

Modeling for Process Control: High-Dimensional Systems  

SciTech Connect

Most of other technologically important systems (among them, powders and other granular systems) are intrinsically nonlinear. This project is focused on building the dynamical models for granular systems as a prototype for nonlinear high-dimensional systems exhibiting complex non-equilibrium phenomena. Granular materials present a unique opportunity to study these issues in a technologically important and yet fundamentally interesting setting. Granular systems exhibit a rich variety of regimes from gas-like to solid-like depending on the external excitation. Based the combination of the rigorous asymptotic analysis, available experimental data and nonlinear signal processing tools, we developed a multi-scale approach to the modeling of granular systems from detailed description of grain-grain interaction on a micro-scale to continuous modeling of large-scale granular flows with important geophysical applications.

Lev S. Tsimring

2008-09-15T23:59:59.000Z

198

Nonlinear Dynamical Model of Regime Switching Between Conventions and Business Cycles  

E-Print Network (OSTI)

We introduce and study a non-equilibrium continuous-time dynamical model of the price of a single asset traded by a population of heterogeneous interacting agents in the presence of uncertainty and regulatory constraints. The model takes into account (i) the price formation delay between decision and investment by the second-order nature of the dynamical equations, (ii) the linear and nonlinear mean-reversal or their contrarian in the form of speculative price trading, (iii) market friction, (iv) uncertainty in the fundamental value which controls the amplitude of mispricing, (v) nonlinear speculative momentum effects and (vi) market regulations that may limit large mispricing drifts. We find markets with coexisting equilibrium, conventions and business cycles, which depend on (a) the relative strength of value-investing versus momentum-investing, (b) the level of uncertainty on the fundamental value and (c) the degree of market regulation. The stochastic dynamics is characterized by nonlinear geometric rando...

Yukalov, V I; Yukalova, E P

2008-01-01T23:59:59.000Z

199

Simulating fermion production in 1+1 dimensional QED  

E-Print Network (OSTI)

We investigate fermion--anti-fermion production in 1+1 dimensional QED using real-time lattice techniques. In this non-perturbative approach the full quantum dynamics of fermions is included while the gauge field dynamics can be accurately represented by classical-statistical simulations for relevant field strengths. We compute the non-equilibrium time evolution of gauge invariant correlation functions implementing 'low-cost' Wilson fermions. Introducing a lattice generalization of the Dirac-Heisenberg-Wigner function, we recover the Schwinger formula in 1+1 dimensions in the limit of a static background field. We discuss the decay of the field due to the backreaction of the created fermion--anti-fermion pairs and apply the approach to strongly inhomogeneous gauge fields. The latter allows us to discuss the striking phenomenon of a linear rising potential building up between produced fermion bunches after the initial electric pulse ceased.

Florian Hebenstreit; Jrgen Berges; Daniil Gelfand

2013-02-22T23:59:59.000Z

200

Geometric universality of currents in an open network of interacting particles  

SciTech Connect

We discuss a non-equilibrium statistical system on a graph or network. Identical particles are injected, interact with each other, traverse, and leave the graph in a stochastic manner described in terms of Poisson rates, possibly dependent on time and instantaneous occupation numbers at the nodes of the graph. We show that under the assumption of the relative rates constancy, the system demonstrates a profound statistical symmetry, resulting in geometric universality of the particle currents statistics. The phenomenon applies broadly to many man-made and natural open stochastic systems, such as queuing of packages over internet, transport of electrons and quasi-particles in mesoscopic systems, and chains of reactions in bio-chemical networks. We illustrate the utility of the general approach using two enabling examples from the two latter disciplines.

Sinitsyn, Nikolai A [Los Alamos National Laboratory; Chernyak, Vladimir Y [Los Alamos National Laboratory; Chertkov, Michael [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

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201

Weak Viscoelastic Nematodynamics of Maxwell Type  

E-Print Network (OSTI)

A constitutive theory for weak viscoelastic nematodynamics of Maxwell type is developed using the standard local approach of non-equilibrium thermodynamics. Along with particular viscoelastic and nematic kinematics, the theory uses the weakly elastic potential proposed by de Gennes for nematic solids and the LEP constitutive equations for viscous nematic liquids, while ignoring the Frank (orientation) elasticity and inertia effects. In spite of many basic parameters, algebraic properties of nematic operations investigated in Appendix, allowed us to reveal a general group structure of the theory and present it in a simple form. It is shown that the evolution equation for director is also viscoelastic. An example of magnetization clarifies the situation with non-symmetric stresses. When the sources of stress asymmetry are absent, the theory is simplified and its relaxation properties are described by a symmetric subgroup of nematic algebraic operations. A purely linear constitutive behavior exemplifies the symmetric situation.

Arkady I. Leonov; Valery S. Volkov

2004-08-26T23:59:59.000Z

202

Spin-blockade effect and coherent control of DNA-damage by free radicals: a proposal on bio-spintronics  

E-Print Network (OSTI)

Coherent control of OH-free radicals interacting with the spin-triplet state of a DNA molecule is investigated. A model Hamiltonian for molecular spin singlet-triplet resonance is developed. We illustrate that the spin-triplet state in DNA molecules can be efficiently populated, as the spin-injection rate can be tuned to be orders of magnitudes greater than the decay rate due to small spin-orbit coupling in organic molecules. Owing to the nano-second life-time of OH free radicals, a non-equilibrium free energy barrier induced by the injected spin triplet state that lasts approximately longer than one-micro second in room temperature can efficiently block the initial Hydrogen abstraction and DNA damage. For a direct demonstration of the spin-blockade effect, a molecular simulation based on an {\\em ab-initio} Car-Parrinello molecular dynamics is deployed.

Abolfath, Ramin M

2011-01-01T23:59:59.000Z

203

Spontaneous emergence of a metabolism  

SciTech Connect

Networks of catalyzed reactions with nonlinear feedback have been proposed to play an important role in the origin of life. We investigate this possibility in a polymer chemistry with catalyzed cleavage and condensation reactions. We study the properties of a well-stirred reactor driven away from equilibrium by the flow of mass. Under appropriate non-equilibrium conditions. The nonlinear feedback of the reaction network focuses the material of the system into a few specific polymer species. The network of catalytic reactions digests'' the material of its environment, incorporating it into its own form. We call the result an autocatalytic metabolism. Under some variations it persists almost unchanged, while in other cases it dies. We argue that the dynamical stability of autocatalytic metabolisms gives them regenerative properties that allow them to repair themselves and to propagate through time. 43 refs., 16 figs., 3 tabs.

Bagley, R.J.; Farmer, J.D. (Los Alamos National Lab., NM (USA) Santa Fe Inst., NM (USA))

1990-01-01T23:59:59.000Z

204

Exploring the mechanisms of protein folding  

E-Print Network (OSTI)

Neither of the two prevalent theories, namely thermodynamic stability and kinetic stability, provides a comprehensive understanding of protein folding. The thermodynamic theory is misleading because it assumes that free energy is the exclusive dominant mechanism of protein folding, and attributes the structural transition from one characteristic state to another to energy barriers. Conversely, the concept of kinetic stability overemphasizes dominant mechanisms that are related to kinetic factors. This article explores the stability condition of protein structures from the viewpoint of meso-science, paying attention to the compromise in the competition between minimum free energy and other dominant mechanisms. Based on our study of complex systems, we propose that protein folding is a meso-scale, dissipative, nonlinear and non-equilibrium process that is dominated by the compromise between free energy and other dominant mechanisms such as environmental factors. Consequently, a protein shows dynamic structures,...

Xu, Ji; Ren, Ying; Li, Jinghai

2013-01-01T23:59:59.000Z

205

Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements  

SciTech Connect

Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

Niemi, K.; O'Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

2013-07-15T23:59:59.000Z

206

Rate-dependent morphology of Li2O2 growth in Li-O2 batteries  

E-Print Network (OSTI)

Compact solid discharge products enable energy storage devices with high gravimetric and volumetric energy densities, but solid deposits on active surfaces can disturb charge transport and induce mechanical stress. In this Letter we develop a nanoscale continuum model for the growth of Li2O2 crystals in lithium-oxygen batteries with organic electrolytes, based on a theory of electrochemical non-equilibrium thermodynamics originally applied to Li-ion batteries. As in the case of lithium insertion in phase-separating LiFePO4 nanoparticles, the theory predicts a transition from complex to uniform morphologies of Li2O2 with increasing current. Discrete particle growth at low discharge rates becomes suppressed at high rates, resulting in a film of electronically insulating Li2O2 that limits cell performance. We predict that the transition between these surface growth modes occurs at current densities close to the exchange current density of the cathode reaction, consistent with experimental observations.

Horstmann, B; Mitchell, R; Bessler, W G; Shao-Horn, Y; Bazant, M Z

2013-01-01T23:59:59.000Z

207

Sedimentation of a two-dimensional colloidal mixture exhibiting liquid-liquid and gas-liquid phase separation: a dynamical density functional theory study  

E-Print Network (OSTI)

We present dynamical density functional theory results for the time evolution of the density distribution of a sedimenting model two-dimensional binary mixture of colloids. The interplay between the bulk phase behaviour of the mixture, its interfacial properties at the confining walls, and the gravitational field gives rise to a rich variety of equilibrium and non-equilibrium morphologies. In the fluid state, the system exhibits both liquid-liquid and gas-liquid phase separation. As the system sediments, the phase separation significantly affects the dynamics and we explore situations where the final state is a coexistence of up to three different phases. Solving the dynamical equations in two-dimensions, we find that in certain situations the final density profiles of the two species have a symmetry that is different from that of the external potentials, which is perhaps surprising, given the statistical mechanics origin of the theory. The paper concludes with a discussion on this.

Alexandr Malijevsky; Andrew J. Archer

2013-09-17T23:59:59.000Z

208

Oscillatory motion of sheared nanorods beyond the nematic phase  

E-Print Network (OSTI)

We study the role of the control parameter triggering nematic order (temperature or concentration) on the dynamical behavior of a system of nanorods under shear. Our study is based on a set of mesoscopic equations of motion for the components of the tensorial orientational order parameter. We investigating these equations via a systematic bifurcation analysis based on a numerical continuation technique, focusing on spatially homogeneous states. Exploring a wide range of parameters we find, unexpectedly, that states with oscillatory motion can exist even under conditions where the equilibrium system is isotropic. These oscillatory states are characterized by wagging motion of the paranematic director, and they occur if the tumbling parameter is sufficiently small. We also present full non-equilibrium phase diagrams, in the plane spanned by the concentration and the shear rate.

David A. Strehober; Harald Engel; Sabine H. L. Klapp

2013-04-03T23:59:59.000Z

209

Entropy production for mechanically or chemically driven biomolecules  

E-Print Network (OSTI)

Entropy production along a single stochastic trajectory of a biomolecule is discussed for two different sources of non-equilibrium. For a molecule manipulated mechanically by an AFM or an optical tweezer, entropy production (or annihilation) occurs in the molecular conformation proper or in the surrounding medium. Within a Langevin dynamics, a unique identification of these two contributions is possible. The total entropy change obeys an integral fluctuation theorem and a class of further exact relations, which we prove for arbitrarily coupled slow degrees of freedom including hydrodynamic interactions. These theoretical results can therefore also be applied to driven colloidal systems. For transitions between different internal conformations of a biomolecule involving unbalanced chemical reactions, we provide a thermodynamically consistent formulation and identify again the two sources of entropy production, which obey similar exact relations. We clarify the particular role degenerate states have in such a description.

Tim Schmiedl; Thomas Speck; Udo Seifert

2006-01-27T23:59:59.000Z

210

Critical dynamics and decoherence  

SciTech Connect

We study dynamics of decoherence in a generic model where the environment is driven and undergoes a quantum phase transition. We model the environment by the Ising chain in the transverse field, and assume that the decohering system is a central spin-1/2. We found that when the environment is quenched slowly through the critical point, the decoherence factor of the central spin undergoes rapid decay that encodes the critical exponents of the environment. We also found that decoherence in a non-equilibrated, kink-contaminated, environment can be stronger than in a vacuum one. We derived a remarkably simple analytical expression that describes post-transition decoherence and predicts periodicities involving all system parameters. This research connects the fields of decoherence, quantum phase transitions, and Kibble-Zurek non-equilibrium dynamics.

Damski, Bogdan [Los Alamos National Laboratory; Quan, Haitao T [Los Alamos National Laboratory; Zurek, Wojciech H [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

211

Introductory statistical mechanics for electron storage rings  

Science Conference Proceedings (OSTI)

These lectures introduce the beam dynamics of electron-positron storage rings with particular emphasis on the effects due to synchrotron radiation. They differ from most other introductions in their systematic use of the physical principles and mathematical techniques of the non-equilibrium statistical mechanics of fluctuating dynamical systems. A self-contained exposition of the necessary topics from this field is included. Throughout the development, a Hamiltonian description of the effects of the externally applied fields is maintained in order to preserve the links with other lectures on beam dynamics and to show clearly the extent to which electron dynamics in non-Hamiltonian. The statistical mechanical framework is extended to a discussion of the conceptual foundations of the treatment of collective effects through the Vlasov equation.

Jowett, J.M.

1986-07-01T23:59:59.000Z

212

Economic benefits of decarbonising the global electricity sector  

E-Print Network (OSTI)

Conventional economic analyses of stringent climate change mitigation have generally concluded that economic austerity would result from carbon austerity. These analyses however rely critically on the assumption of an economic equilibrium, which dismisses established notions on behavioural heterogeneity, path dependence and technology transitions. Here we show that on the contrary, the decarbonisation of the electricity sector globally can lead to improvements in economic performance. By modelling the process of innovation-diffusion and non-equilibrium dynamics, we establish how climate policy instruments for emissions reductions alter economic activity through energy prices, government spending, enhanced investment and tax revenues. While higher electricity prices reduce income and output, this is over-compensated by enhanced employment generated by investments in new technology. We stress that the current dialogue on the impacts of climate policies must be revisited to reflect the real complex dynamics invo...

Mercure, J F; Foley, A; Chewpreecha, U; Pollitt, H; Holden, P B; Edwards, N R

2013-01-01T23:59:59.000Z

213

Toward the AdS/CFT Gravity Dual for High Energy Collisions: II. The Stress Tensor on the Boundary  

E-Print Network (OSTI)

In this second paper of the series we calculate the stress tensor of excited matter, created by ``debris'' of high energy collisions at the boundary. We found that massive objects (``stones'') falling into the AdS center produce gravitational disturbance which however has $zero$ stress tensor at the boundary. The falling open strings, connected to receeding charges, do produce a nonzero stress tensor which we found analytically from time-dependent linearized Einstein equations in the bulk. It corresponds to exploding non-equilibrium matter: we discuss its behavior in some detail, including its internal energy density in a comoving frame and the ``freezeout surfaces''. We then discuss what happens for the ensemble of strings.

Shu Lin; Edward Shuryak

2007-11-05T23:59:59.000Z

214

Thermodynamics in Modified Gravity Theories  

E-Print Network (OSTI)

We demonstrate that there does exist an equilibrium description of thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \\phi, X)$, where $R$ is the Ricci scalar and $X$ is the kinetic energy of a scalar field $\\phi$. This comes from a suitable definition of an energy momentum tensor of the "dark" component obeying the local energy conservation law in the Jordan frame. It is shown that the equilibrium description in terms of the horizon entropy $S$ is convenient because it takes into account the contribution of the horizon entropy $\\hat{S}$ in non-equilibrium thermodynamics as well as an entropy production term.

Kazuharu Bamba; Chao-Qiang Geng; Shinji Tsujikawa

2011-01-19T23:59:59.000Z

215

Phase transitions in the early and the present Universe  

E-Print Network (OSTI)

The evolution of the Universe is the ultimate laboratory to study fundamental physics across energy scales that span about 25 orders of magnitude: from the grand unification scale through particle and nuclear physics scales down to the scale of atomic physics. The standard models of cosmology and particle physics provide the basic understanding of the early and present Universe and predict a series of phase transitions that occurred in succession during the expansion and cooling history of the Universe. We survey these phase transitions, highlighting the equilibrium and non-equilibrium effects as well as their observational and cosmological consequences. We discuss the current theoretical and experimental programs to study phase transitions in QCD and nuclear matter in accelerators along with the new results on novel states of matter as well as on multi- fragmentation in nuclear matter. A critical assessment of similarities and differences between the conditions in the early universe and those in ultra- relat...

Boyanovsky, D; Schwarz, Dominik J

2006-01-01T23:59:59.000Z

216

Spinor Bose gases: Explorations of symmetries, magnetism and quantum dynamics  

E-Print Network (OSTI)

Spinor Bose gases form a family of quantum fluids manifesting both magnetic order and superfluidity. This article reviews experimental and theoretical progress in understanding the static and dynamic properties of these fluids. The connection between system properties and the rotational symmetry properties of the atomic states and their interactions are investigated. Following a review of the experimental techniques used for characterizing spinor gases, their mean-field and many-body ground states, both in isolation and under the application of symmetry-breaking external fields, are discussed. These states serve as the starting point for understanding low-energy dynamics, spin textures and topological defects, effects of magnetic dipole interactions, and various non-equilibrium collective spin-mixing phenomena. The paper aims to form connections and establish coherence among the vast range of works on spinor Bose gases, so as to point to open questions and future research opportunities.

Stamper-Kurn, Dan M

2012-01-01T23:59:59.000Z

217

Resonant Relaxation in Electroweak Baryogenesis  

E-Print Network (OSTI)

We compute the leading, chiral charge-changing relaxation term in the quantum transport equations that govern electroweak baryogenesis using the closed time path formulation of non-equilibrium quantum field theory. We show that the relaxation transport coefficients may be resonantly enhanced under appropriate conditions on electroweak model parameters and that such enhancements can mitigate the impact of similar enhancements in the CP-violating source terms. We also develop a power counting in the time and energy scales entering electroweak baryogenesis and include effects through second order in ratios $\\epsilon$ of the small and large scales. We illustrate the implications of the resonantly enhanced ${\\cal O}(\\epsilon^2)$ terms using the Minimal Supersymmetric Standard Model, focusing on the interplay between the requirements of baryogenesis and constraints obtained from collider studies, precision electroweak data, and electric dipole moment searches.

Lee, C; Ramsey-Musolf, M J; Lee, Christopher; Cirigliano, Vincenzo; Ramsey-Musolf, Michael J.

2004-01-01T23:59:59.000Z

218

Resonant Relaxation in Electroweak Baryogenesis  

E-Print Network (OSTI)

We compute the leading, chiral charge-changing relaxation term in the quantum transport equations that govern electroweak baryogenesis using the closed time path formulation of non-equilibrium quantum field theory. We show that the relaxation transport coefficients may be resonantly enhanced under appropriate conditions on electroweak model parameters and that such enhancements can mitigate the impact of similar enhancements in the CP-violating source terms. We also develop a power counting in the time and energy scales entering electroweak baryogenesis and include effects through second order in ratios $\\epsilon$ of the small and large scales. We illustrate the implications of the resonantly enhanced ${\\cal O}(\\epsilon^2)$ terms using the Minimal Supersymmetric Standard Model, focusing on the interplay between the requirements of baryogenesis and constraints obtained from collider studies, precision electroweak data, and electric dipole moment searches.

Christopher Lee; Vincenzo Cirigliano; Michael J. Ramsey-Musolf

2004-12-23T23:59:59.000Z

219

Aging, phase ordering and conformal invariance  

E-Print Network (OSTI)

In a variety of systems which exhibit aging, the two-time response function scales as $R(t,s)\\approx s^{-1-a} f(t/s)$. We argue that dynamical scaling can be extended towards conformal invariance, obtaining thus the explicit form of the scaling function $f$. This quantitative prediction is confirmed in several spin systems, both for $Tnon-equilibrium critical dynamics). The 2D and 3D Ising models with Glauber dynamics are studied numerically, while exact results are available for the spherical model with a non-conserved order parameter, both for short-ranged and long-ranged interactions, as well as for the mean-field spherical spin glass.

Malte Henkel; Michel Pleimling; Claude Godreche; Jean-Marc Luck

2001-07-13T23:59:59.000Z

220

Dissipation in a Quantum Wire: Fact and Fantasy  

Science Conference Proceedings (OSTI)

Where, and how, does energy dissipation of electrical energy take place in a ballistic wire? Fully two decades after the advent of the transmissive phenomenology of electrical conductance, this deceptively simple query remains unanswered. We revisit the quantum kinetic basis of dissipation and show its power to give a definitive answer to our query. Dissipation leaves a clear, quantitative trace in the non-equilibrium current noise of a quantum point contact; this signature has already been observed in the laboratory. We then highlight the current state of accepted understandings in the light of well-known yet seemingly contradictory measurements. The physics of mesoscopic transport rests not in coherent carrier transmission through a perfect and dissipationless metallic channel, but explicitly in their dissipative inelastic scattering at the wire's interfaces and adjacent macroscopic leads.

Das, Mukunda P. [Department of Theoretical Physics, IAS, Australian National University, Canberra, ACT 0200 (Australia); Green, Frederick [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

2008-10-23T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

The dynamics of technology diffusion and the impacts of climate policy instruments in the decarbonisation of the global electricity sector  

E-Print Network (OSTI)

This paper presents an analysis of possible uses of climate policy instruments for the decarbonisation of the global electricity sector in a non-equilibrium economic and technology innovation-diffusion perspective. Emissions reductions occur through changes in technology and energy consumption; in this context, investment decision-making opportunities occur periodically, which energy policy can incentivise in order to transform energy systems and meet reductions targets. Energy markets are driven by innovation, dynamic costs and technology diffusion; yet, the incumbent systems optimisation methodology in energy modelling does not address these aspects nor the effectiveness of policy onto decision-making since the dynamics modelled take their source from the top-down `social-planner' assumption. This leads to an underestimation of strong technology lock-ins in cost-optimal scenarios of technology. Our approach explores the global diffusion of low carbon technology in connection to a highly disaggregated sector...

Mercure, J -F; Foley, A M; Chewpreecha, U; Pollitt, H

2013-01-01T23:59:59.000Z

222

Ultrasfast Dynamics in Dense Hydrogen Explored at Flash  

DOE Green Energy (OSTI)

The short pulse duration and high intensity of the FLASH (Free-electron LASer in Hamburg) allows us to generate and probe homogeneous warm dense non-equilibrium hydrogen within a single extreme ultraviolet (EUV) light pulse. By analyzing the spectrum of the 13.5 nm Thomson scattered light we determine the plasma temperature and density. We find that classical models of this interaction are in good agreement with our dense plasma conditions. In a FEL-pump FEL-probe experiment droplets of liquid hydrogen and their scattering behavior for different pump-probe setups were observed under 20{sup o} and 90{sup o}. We find that the scattering behavior of the scattered intensity depends on the scattering angle.

Hilbert, V; Zastrau, U; Neumayer, P; Hochhaus, D; Toleikis, S; Harmand, M; Przystawik, A; Tschentscher, T; Glenzer, S H; Doeppner, T; Fortmann, C; White, T; Gregori, G; Gode, S; Tiggesbaumker, J; Skruszewicz, S; Meiwes-Broer, K H; Sperling, P; Redmer, R; Forster, E

2011-08-01T23:59:59.000Z

223

Scaling Relations for Turbulence in Multiphase Interstellar Medium  

E-Print Network (OSTI)

We simulate the dynamics of phase transition in radiatively cooling interstellar gas in three dimensions with a high order hydrodynamic method. We have previously shown (Kritsuk & Norman 2002a) in simulations with non-equilibrium initial conditions that thermal instability induces supersonic turbulence as a by-product of the phase transition which leads to formation of multiphase medium. We rely on a generalization of the She & Leveque (1994) model to study velocity scaling relations in this decaying turbulence and compare those with analogous results for compressible isothermal turbulence. Since radiative cooling promotes nonlinear instabilities in highly supersonic flows, turbulence in our simulations tends to be more intermittent than in the isothermal case. Hausdorff dimension of the most singular dissipative structures, D, can be as high as 2.3, while in supersonic isothermal turbulence D is limited by a more primitive nature of dissipation (shocks): D<=2. We also show that single-phase veloci...

Kritsuk, A G; Kritsuk, Alexei G.; Norman, Michael L.

2004-01-01T23:59:59.000Z

224

Phantom dark energy as an effect of bulk viscosity  

E-Print Network (OSTI)

In a homogeneous and isotropic universe bulk viscosity is the unique viscous effect capable to modify the background dynamics. Effects like shear viscosity or heat conduction can only change the evolution of the perturbations. The existence of a bulk viscous pressure in a fluid, which in order to obey to the second law of thermodynamics is negative, reduces its effective pressure. We discuss in this study the degeneracy in bulk viscous cosmologies and address the possibility that phantom dark energy cosmology could be caused by the existence of non-equilibrium pressure in any cosmic component. We establish the conditions under which either matter or radiation viscous cosmologies can be mapped into the phantom dark energy scenario with constraints from multiple observational data-sets

Hermano Velten; Jiaxin Wang; Xinhe Meng

2013-07-16T23:59:59.000Z

225

Prediction of Transport Properties by Molecular Simulation: Methanol and Ethanol and their mixture  

E-Print Network (OSTI)

Transport properties of liquid methanol and ethanol are predicted by molecular dynamics simulation. The molecular models for the alcohols are rigid, non-polarizable and of united-atom type. They were developed in preceding work using experimental vapor-liquid equilibrium data only. Self- and Maxwell-Stefan diffusion coefficients as well as the shear viscosity of methanol, ethanol and their binary mixture are determined using equilibrium molecular dynamics and the Green-Kubo formalism. Non-equilibrium molecular dynamics is used for predicting the thermal conductivity of the two pure substances. The transport properties of the fluids are calculated over a wide temperature range at ambient pressure and compared with experimental and simulation data from the literature. Overall, a very good agreement with the experiment is found. For instance, the self-diffusion coefficient and the shear viscosity are predicted with average deviations of less 8% for the pure alcohols and 12% for the mixture. The predicted thermal...

Guevara-Carrion, Gabriela; Vrabec, Jadran; Hasse, Hans

2009-01-01T23:59:59.000Z

226

Superlubricity through graphene multilayers between Ni(111) surfaces  

E-Print Network (OSTI)

A single graphene layer placed between two parallel Ni(111) surfaces screens the strong attractive force and results in a significant reduction of adhesion and sliding friction. When two graphene layers are inserted, each graphene is attached to one of the metal surfaces with a significant binding and reduces the adhesion further. In the sliding motion of these surfaces the transition from stick-slip to continuous sliding is attained, whereby non-equilibrium phonon generation through sudden processes is suppressed. The adhesion and corrugation strength continues to decrease upon insertion of the third graphene layer and eventually saturates at a constant value with increasing number of graphene layers. In the absence of Ni surfaces, the corrugation strength of multilayered graphene is relatively higher and practically independent of the number of layers. Present first-principles calculations reveal the superlubricant feature of graphene layers placed between pseudomorphic Ni(111) surfaces, which is achieved t...

Cahangirov, S; zelik, V Ongun

2013-01-01T23:59:59.000Z

227

'Genesis': A takeover from field-responsive matter?  

E-Print Network (OSTI)

Cairns-Smith (2008) has argued for a pre-Darwinian era, with a simpler basis for life's functioning via primitive "crystal genes" (information transfer, kinetic control on metabolic reactions). At the other extreme, guided by the structural similarity of clusters in early-evolved enzymes to iron-sulphide minerals like greigite, the hydrothermal mound scenario of Russell and coworkers (1994) presents how non-equilibrium forces rooted in geochemistry could be extrapolated to understand the metabolic functioning of living systems. The informational vs metabolic aspects of life in these respective scenarios can be linked together via a framboid-based theory of Sawlowicz (2000), as these assemblies typically form in colloidal environments. In this background, we consider the ramifications of a magnetic rock field on the mound scenario, asking if soft matter assemblies are compatible with a coherent order.

Mitra-Delmotte, Gargi

2010-01-01T23:59:59.000Z

228

'Genesis': A takeover from field-responsive matter?  

E-Print Network (OSTI)

Cairns-Smith (2008) has argued for a pre-Darwinian era, with a simpler basis for life's functioning via primitive "crystal genes" (information transfer, kinetic control on metabolic reactions). At the other extreme, guided by the structural similarity of clusters in early-evolved enzymes to iron-sulphide minerals like greigite, the hydrothermal mound scenario of Russell and coworkers (1994) presents how non-equilibrium forces rooted in geochemistry could be extrapolated to understand the metabolic functioning of living systems. The informational vs metabolic aspects of life in these respective scenarios can be linked together via a framboid-based theory of Sawlowicz (2000), as these assemblies typically form in colloidal environments. In this background, we consider the ramifications of a magnetic rock field on the mound scenario, asking if soft matter assemblies are compatible with a coherent order.

Gargi Mitra-Delmotte; Asoke N. Mitra

2010-08-13T23:59:59.000Z

229

Accuracy of the Frensley inflow boundary condition for Wigner equations in simulating resonant tunneling diodes  

SciTech Connect

In this paper, the accuracy of the Frensley inflow boundary condition of the Wigner equation is analyzed in computing the I-V characteristics of a resonant tunneling diode (RTD). It is found that the Frensley inflow boundary condition for incoming electrons holds only exactly infinite away from the active device region and its accuracy depends on the length of contacts included in the simulation. For this study, the non-equilibrium Green's function (NEGF) with a Dirichlet to Neumann mapping boundary condition is used for comparison. The I-V characteristics of the RTD are found to agree between self-consistent NEGF and Wigner methods at low bias potentials with sufficiently large GaAs contact lengths. Finally, the relation between the negative differential conductance (NDC) of the RTD and the sizes of contact and buffer in the RTD is investigated using both methods.

Jiang Haiyan [Department of Applied Mathematics, Beijing Institute of Technology, Beijing 100081 (China); Department of Mathematics and Statistics, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Cai Wei, E-mail: wcai@uncc.ed [Department of Mathematics and Statistics, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States); Tsu, Raphael [Department of Electrical and Computer Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223-0001 (United States)

2011-03-01T23:59:59.000Z

230

Two-phase jet loads. [PWR  

Science Conference Proceedings (OSTI)

Two-phase jets are currently being studied to improve engineering models for the prediction of loads on pipes and structures during LOCAs. Multi-dimensional computer codes such as BEACON/MOD2, CSQ, and TRAC-P1A are being employed to predict flow characteristics and flow-structure loading. Our ultimate goal is to develop a new approximate engineering model which is superior to the F.J. Moody design model. Computer results are compared with data obtained from foreign sources, and a technique for using the TRAC-P1A vessel component as a containment model is presented. In general, good agreement with the data is obtained for saturated stagnation conditions; however, difficulties are encountered for subcooled stagnation conditions, possibly due to nucleation delay and non-equilibrium effects.

Tomasko, D.

1980-01-01T23:59:59.000Z

231

Statistical physics ""Beyond equilibrium  

Science Conference Proceedings (OSTI)

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

Ecke, Robert E [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

232

Glassy Aging with Modified Kohlrausch-Williams-Watts Form  

E-Print Network (OSTI)

In this report we address the question whether aging in the non equilibrium glassy state is controlled by the equilibrium alpha-relaxation process which occur at temperatures above Tg. Recently Lunkenheimer et. al. [Phys. Rev. Lett. 95, 055702 (2005)] proposed a model for the glassy aging data of dielectric relaxation using a modified Kohlrausch-Williams-Watts (KWW) form. The aging time dependence of the relaxation time is defined by these authors through a functional relation involving the corresponding frequency but the stretching exponent is same as the alpha-relaxation stretching exponent. We present here an alternative functional form directly involving the relaxation time itself. The proposed model fits the data of Lunkenheimer et. al. perfectly with a stretching exponent different from the alpha-relaxation stretching exponent.

Bhaskar Sen Gupta; Shankar P. Das

2007-12-27T23:59:59.000Z

233

Optimal and robust energy transport in light-harvesting complexes: (II) A quantum interplay of multichromophoric geometries and environmental interactions  

E-Print Network (OSTI)

Today, the physical principles for the high efficiency of excitation energy transfer in light-harvesting complexes are still not fully understood. Notably, the degree of robustness of these systems for transporting energy is not known considering their realistic interactions with vibrational and radiative environments within the surrounding solvent and scaffold proteins. In this work, we employ an efficient technique to simulate ultrafast quantum dynamics of such complex excitonic systems in their non-equilibrium environment in the non-perturbative and non-Markovian regimes. We demonstrate that the natural dynamics of the FMO complex leads to optimum and stable energy transport due to a convergence of energy/time scales among important internal and external parameters. In particular, we show that the FMO energy transfer efficiency is optimal and robust with respect to all the relevant parameters of environmental interactions and Frenkel-exciton Hamiltonian including reorganization energy \\lambda, bath frequen...

Mohseni, Masoud; Lloyd, Seth; Rabitz, Herschel

2011-01-01T23:59:59.000Z

234

Reaction Diffusion in the Silver-Zinc and Silver-Aluminum Systems  

SciTech Connect

Multiphase diffusion was investigated in the silver-zinc and silver-aluminum binary systems using metallographic and electron microprobe techniques. Diffusion couples in the silver-zinc system were prepared by electroplating silver onto coupons of a AgZn alloy (62.2% Ag), and diffusion behavior was studied at 600 and 650 degrees C. Couples in the silver-aluminum system were prepared by electroplating silver onto coupons of a AgAl alloy (87.7% Ag) and diffusion measurements were made between 400-600 degrees C. Significant deviations from equilibrium compositions were observed at the moving interphase boundary in each couple. The nucleation of a non-equilibrium silver-rich phase was observed at the location of the initial interface in many of the couples.

Braun, Japnell D.; Powell, Gordon W.

1971-10-01T23:59:59.000Z

235

On conditions of negativity of friction resistance for non-stationary modes of blood flow and possible mechanism of affecting of environmental factors on energy effectiveness of cardio-vascular system functioning  

E-Print Network (OSTI)

It is shown that initiated by action of molecular viscosity impulse flow, directed usually from the moving fluid to limiting it solid surface, can, under certain conditions, turn to zero and get negative values in the case of non-stationary flow caused by alternating in time longitudinal (along the pipe axis) pressure gradient. It is noted that this non-equilibrium mechanism of negative friction resistance in the similar case of pulsating blood flow in the blood vessels, in addition to the stable to turbulent disturbances swirled blood flow structure providing, can also constitute hydro-mechanical basis of the observed but not explained yet paradoxically high energy effectiveness of the normal functioning of the cardio-vascular system (CVS). We consider respective mechanism of affecting on the stability of the normal work of CVS by environmental variable factors using shifting of hydro-dynamic mode with negative resistance realization range boundaries and variation of linear hydro-dynamic instability leading ...

Chefranov, S G

2013-01-01T23:59:59.000Z

236

Gaussian tripartite entanglement out of equilibrium  

E-Print Network (OSTI)

The stationary multipartite entanglement between three interacting harmonic oscillators subjected to decoherence is analyzed in the largely unexplored non-equilibrium strong dissipation regime. We compute the exact asymptotic Gaussian state of the system and elucidate its separability properties, qualitatively assessing the regions of the space of parameters in which fully inseparable states are generated. Interestingly, the sharing structure of bipartite entanglement is seen to degrade as dissipation increases even for very low temperatures, at which the system approaches its ground state. We also find that establishing stationary energy currents across the harmonic chain does not correspond with the build-up of biseparable steady states, which relates instead just to the relative intensity of thermal fluctuations.

Antonio A. Valido; Luis A. Correa; Daniel Alonso

2013-05-21T23:59:59.000Z

237

Macroscopic coherence between quantum condensates formed at different times  

E-Print Network (OSTI)

We demonstrate macroscopic coherence between quantum condensates generated at different times, separated by more than the particle dephasing time. This is possible due to the dressed light-matter nature of exciton-polaritons, which can be injected resonantly by optical excitation at well-defined momenta. We show that the build-up of coherence between condensates depends on the interaction between the particles, particle density, as well as temperature despite the non-equilibrium nature of the condensate, whereas the mass of the particles plays no role in the condensation of resonantly injected polaritons. This experiment also makes it possible for us to measure directly the large nonlinear phase shift resulting from the polariton-polariton interaction energy. Our results provide direct evidence for coherence between different condensates and demonstrate a new approach for probing their ultrafast dynamics, opening new directions in the study of matter coherence as well as in practical applications such as quantum information and ultrafast logic.

Alex Hayat; Christoph Lange; Lee A. Rozema; Rockson Chang; Shreyas Potnis; Henry M. van Driel; Aephraim M. Steinberg; Mark Steger; David W. Snoke; Loren N. Pfeiffer; Kenneth W. West

2013-09-30T23:59:59.000Z

238

CX-004918: Categorical Exclusion Determination | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

8: Categorical Exclusion Determination 8: Categorical Exclusion Determination CX-004918: Categorical Exclusion Determination Sheetak -Non-Equilibrium Asymmetric Thermoelectric Devices CX(s) Applied: B3.6 Date: 08/10/2010 Location(s): Austin, Texas Office(s): Advanced Research Projects Agency - Energy Funding will support bench-scale research and development on a novel thermoelectric device for use in various air conditioning applications. The proposed work is consistent with the goals of Building Energy Efficiency Through Innovative Thermodevices: the development of energy efficient cooling technologies and air conditioners for buildings, to save energy and reduce greenhouse gas emissions. Proposed work consists entirely of research, development, and demonstration work to be completed in Sheetak's

239

On the Accuracy of Finite-Volume Schemes for Fluctuating Hydrodynamics  

E-Print Network (OSTI)

This paper describes the development and analysis of finite-volume methods for the Landau-Lifshitz Navier-Stokes (LLNS) equations and related stochastic partial differential equations in fluid dynamics. The LLNS equations incorporate thermal fluctuations into macroscopic hydrodynamics by the addition of white-noise fluxes whose magnitudes are set by a fluctuation-dissipation relation. Originally derived for equilibrium fluctuations, the LLNS equations have also been shown to be accurate for non-equilibrium systems. Previous studies of numerical methods for the LLNS equations focused primarily on measuring variances and correlations computed at equilibrium and for selected non-equilibrium flows. In this paper, we introduce a more systematic approach based on studying discrete equilibrium structure factors for a broad class of explicit linear finite-volume schemes. This new approach provides a better characterization of the accuracy of a spatio-temporal discretization as a function of wavenumber and frequency, allowing us to distinguish between behavior at long wavelengths, where accuracy is a prime concern, and short wavelengths, where stability concerns are of greater importance. We use this analysis to develop a specialized third-order Runge Kutta scheme that minimizes the temporal integration error in the discrete structure factor at long wavelengths for the one-dimensional linearized LLNS equations. Together with a novel method for discretizing the stochastic stress tensor in dimension larger than one, our improved temporal integrator yields a scheme for the three-dimensional equations that satisfies a discrete fluctuation-dissipation balance for small time steps and is also sufficiently accurate even for time steps close to the stability limit.

A. Donev; E. Vanden-Eijnden; A. L. Garcia; J. B. Bell

2009-06-12T23:59:59.000Z

240

Winds of M- and S-type AGB stars: an unorthodox suggestion for the driving mechanism  

E-Print Network (OSTI)

Current knowledge suggests that the dust-driven wind scenario provides a realistic framework for understanding mass loss from C-rich AGB stars. For M-type objects, however, recent detailed models demonstrate that radiation pressure on silicate grains is not sufficient to drive the observed winds, contrary to previous expectations. In this paper, we suggest an alternative mechanism for the mass-loss of M-type AGB stars, involving the formation of both carbon and silicate grains due to non-equilibrium effects, and we study the viability of this scenario. We model the dynamical atmospheres and winds of AGB stars by solving the coupled system of frequency-dependent radiation hydrodynamics and time-dependent dust formation, using a parameterized description of non-equilibrium effects in the gas phase. This approach allows us to assess under which circumstances it is possible to drive winds with small amounts of carbon dust and to get silicate grains forming in these outflows at the same time. The properties of the resulting wind models, such as mass loss rates and outflow velocities, are well within the observed limits for M-type AGB stars. Furthermore, according to our results, it is quite unlikely that significant amounts of silicate grains will condense in a wind driven by a force totally unrelated to dust formation, as the conditions in the upper atmosphere and wind acceleration region put strong constraints on grain growth. The proposed scenario provides a natural explanation for the observed similarities in wind properties of M-type and C-type AGB stars and implies a smooth transition for stars with increasing carbon abundance, from solar-composition to C-rich AGB stars, possibly solving the long-standing problem of the driving mechanism for stars with C/O close to one.

S. Hoefner; A. C. Andersen

2007-02-16T23:59:59.000Z

Note: This page contains sample records for the topic "gc5 non-equilibrium brn" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Simulations of Turbulent Flows with Strong Shocks and Density Variations  

SciTech Connect

In this report, we present the research efforts made by our group at UCLA in the SciDAC project ???¢????????Simulations of turbulent flows with strong shocks and density variations???¢???????. We use shock-fitting methodologies as an alternative to shock-capturing schemes for the problems where a well defined shock is present. In past five years, we have focused on development of high-order shock-fitting Navier-Stokes solvers for perfect gas flow and thermochemical non-equilibrium flow and simulation of shock-turbulence interaction physics for very strong shocks. Such simulation has not been possible before because the limitation of conventional shock capturing methods. The limitation of shock Mach number is removed by using our high-order shock-fitting scheme. With the help of DOE and TeraGrid/XSEDE super computing resources, we have obtained new results which show new trends of turbulence statistics behind the shock which were not known before. Moreover, we are also developing tools to consider multi-species non-equilibrium flows. The main results are in three areas: (1) development of high-order shock-fitting scheme for perfect gas flow, (2) Direct Numerical Simulation (DNS) of interaction of realistic turbulence with moderate to very strong shocks using super computing resources, and (3) development and implementation of models for computation of mutli-species non-quilibrium flows with shock-fitting codes.

Xiaolin Zhong

2012-12-13T23:59:59.000Z

242

Size separation in vibrated granular matter  

E-Print Network (OSTI)

We review recent developments in size separation in vibrated granular materials. Motivated by a need in industry to efficiently handle granular materials and a desire to make fundamental advances in non-equilibrium physics, experimental and theoretical investigations have shown size separation to be a complex phenomena. Large particles in a vibrated granular system invariably rise to the top. However, they may also sink to the bottom, or show other patterns depending on subtle variations in physical conditions. While size ratio is a dominant factor, particle specific properties such as density, inelasticity and friction can play an important role. The nature of the energy input, boundary conditions and interstitial air have been also shown to be significant factors in determining spatial distributions. The presence of convection can enhance mixing or lead to size separation. Experimental techniques including direct visualization and magnetic resonance imaging are being used to investigate these properties. Molecular dynamics and Monte Carlo simulation techniques have been developed to probe size separation. Analytical methods such as kinetic theory are being used to study the interplay between particle size and density in the vibro-fluidized regime, and geometric models have been proposed to describe size separation for deep beds. Besides discussing these studies, we will also review the impact of inelastic collision and friction on the density and velocity distributions to gain a deeper appreciation of the non-equilibrium nature of the system. While a substantial number of studies have been accomplished, considerable work is still required to achieve a firm description of the phenomena.

A. Kudrolli

2004-02-06T23:59:59.000Z

243

Fully integrated transport approach to heavy ion reactions with an intermediate hydrodynamic stage  

E-Print Network (OSTI)

We present a coupled Boltzmann and hydrodynamics approach to relativistic heavy ion reactions. This hybrid approach is based on the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) transport approach with an intermediate hydrodynamical evolution for the hot and dense stage of the collision. Event-by-event fluctuations are directly taken into account via the non-equilibrium initial conditions generated by the initial collisions and string fragmentations in the microscopic UrQMD model. After a (3+1)-dimensional ideal hydrodynamic evolution, the hydrodynamical fields are mapped to hadrons via the Cooper-Frye equation and the subsequent hadronic cascade calculation within UrQMD proceeds to incorporate the important final state effects for a realistic freeze-out. This implementation allows to compare pure microscopic transport calculations with hydrodynamic calculations using exactly the same initial conditions and freeze-out procedure. The effects of the change in the underlying dynamics - ideal fluid dynamics vs. non-equilibrium transport theory - will be explored. The freeze-out and initial state parameter dependences are investigated for different observables. Furthermore, the time evolution of the baryon density and particle yields are discussed. We find that the final pion and proton multiplicities are lower in the hybrid model calculation due to the isentropic hydrodynamic expansion while the yields for strange particles are enhanced due to the local equilibrium in the hydrodynamic evolution. The results of the different calculations for the mean transverse mass excitation function, rapidity and transverse mass spectra for different particle species at three different beam energies are discussed in the context of the available data.

Hannah Petersen; Jan Steinheimer; Gerhard Burau; Marcus Bleicher; Horst Stcker

2008-06-10T23:59:59.000Z

244

Theoretical investigation of thermophysical properties in two-temperature argon-helium thermal plasma  

SciTech Connect

The thermophysical properties of argon-helium thermal plasma have been studied in the temperature range from 5000 to 40 000 K at atmospheric pressure in local thermodynamic equilibrium and non-local thermodynamic equilibrium conditions. Two cases of thermal plasma considered are (i) ground state plasma in which all the atoms and ions are assumed to be in the ground state and (ii) excited state plasma in which atoms and ions are distributed over various possible excited states. The influence of electronic excitation and non-equilibrium parameter {theta} = T{sub e}/T{sub h} on thermodynamic properties (composition, degree of ionization, Debye length, enthalpy, and total specific heat) and transport properties (electrical conductivity, electron thermal conductivity, and thermal diffusion ratio) have been studied. Within the framework of Chapman-Enskog method, the higher-order contributions to transport coefficient and their convergence are studied. The influence of different molar compositions of argon-helium plasma mixture on convergence of higher-orders is investigated. Furthermore, the effect of different definitions of Debye length has also been examined for electrical conductivity and it is observed that electrical conductivity with the definition of Debye length (in which only electrons participate in screening) is less than that of the another definition (in which both the electrons and ions participate in screening) and this deviation increases with electron temperature. Finally, the effect of lowering of ionization energy is examined on electron number density, Debye length, and higher-order contribution to electrical conductivity. It is observed that the lowering of the ionization energy affects the electron transport-properties and consequently their higher-order contributions depending upon the value of the non-equilibrium parameter {theta}.

Sharma, Rohit; Singh, Kuldip [Department of Physics, Guru Nanak Dev University, Amritsar (India); Singh, Gurpreet [Department of Physics, DAV College, Bathinda (India)

2011-08-15T23:59:59.000Z

245

CHEMICAL EFFECTS OF PHOTONUCLEAR REACTIONS IN THE PROPYL BROMIDES  

SciTech Connect

When nuclear reactions occur in atoms in molecules chemical changes follow as a result of the recoil of the product atoms. The nature of these chemical changes was studied intensively for a number of systems but in most cases the magnitude of the recoil energy was about the same. In the present studies use was made of a much greater recoil energy than that normally used. The reaction Br( gamma ,n)Br* gives a recoil bromine atom with an energy of the order of 10/sup 5/ ev, compared to 10/sup 2/ ev for the product of the Br(n, gamma )Br* reaction which is ususlly used. The chemical nature of the products resulting when the propyl bromides were irradiated with neutrons and 70-Mev gamma rays was studied by established techniques. It is possible to differentiate between the reactions which occur while the recoiling bromine atom still is highly energetic, or hot,'' and those which occur after it has been slowed down to thermal energies. The products of the hot reactions show little dependence on the intial recoil energy. In the case of the thermal reactions, the higher energy recoil produces a greater number of products which are different from the original molecules. This can be attributed to the presence of a higher concentration of free radical fragments which are produced in slowing down the higher energy recoiling atom. These fragments combine with the radioactive bromine after it has reached thermal energies to form a greater variety and amount of new products. (auth)

Richardson, A.E.; Voigt, A.F.

1956-12-01T23:59:59.000Z

246

UHM/HNEI EV test and evaluation program  

SciTech Connect

The electric vehicle (EV) program of the Hawaii Natural Energy Institute (HNEI) focuses primarily on the field testing of promising EV/traction batteries. The intent is to utilize typical driving cycles to develop information that verifies or refutes what is obtained in the laboratory. Three different types of battery were assigned by the US DOE for testing in this program: Sonnenschein Dryfit 6V-160, Exide GC-5, Trojan T-145. We added the following battery to the test program: ALCO2200. HNEI's existing EVs were utilized as test beds. The following EVs were chosen in our program: Converted Ford Escort station wagon, Converted Ford Escort two-door sedan, Converted Ford Escort two-door sedan, Converted Dodge van (typically daily driving distances, 10--30 miles). Capacity testing is a very effective way of monitoring the status of battery modules. Based on capacity tests, corrective action such as battery replacement, additional charging, adjusting terminal connections, etc., may be taken to maintain good performance. About 15,500 miles and 600 cycles have been accumulated on the Sonnenschein Dryfit 6V-160 battery pack. Five of its 18 modules have been changed. Based on DOE's standard, the battery has reached the end of its useful life. Nevertheless, the battery pack is still operational and its operating range is still greater than 40 miles per charge. It is too early to evaluate the life expectancy of the other three batteries, the Trojan T-145, Exide GC-5, and Alco 2200. No module has been replaced in these three packs. The Trojan T-145 battery is a very promising EV traction battery in terms of quality and reliability versus price. HNEI will keep the Trojan and Exide battery packs in operation. The Alco 2200 batteries will be transferred to another vehicle. The Additional Charging Method seems to be an effective way of restoring weak modules. The Smart Voltmeter'' developed by HNEI is a promising way of monitoring the remaining range for an EV.

1992-03-01T23:59:59.000Z

247

UHM/HNEI EV test and evaluation program. Final report  

SciTech Connect

The electric vehicle (EV) program of the Hawaii Natural Energy Institute (HNEI) focuses primarily on the field testing of promising EV/traction batteries. The intent is to utilize typical driving cycles to develop information that verifies or refutes what is obtained in the laboratory. Three different types of battery were assigned by the US DOE for testing in this program: Sonnenschein Dryfit 6V-160, Exide GC-5, Trojan T-145. We added the following battery to the test program: ALCO2200. HNEI`s existing EVs were utilized as test beds. The following EVs were chosen in our program: Converted Ford Escort station wagon, Converted Ford Escort two-door sedan, Converted Ford Escort two-door sedan, Converted Dodge van (typically daily driving distances, 10--30 miles). Capacity testing is a very effective way of monitoring the status of battery modules. Based on capacity tests, corrective action such as battery replacement, additional charging, adjusting terminal connections, etc., may be taken to maintain good performance. About 15,500 miles and 600 cycles have been accumulated on the Sonnenschein Dryfit 6V-160 battery pack. Five of its 18 modules have been changed. Based on DOE`s standard, the battery has reached the end of its useful life. Nevertheless, the battery pack is still operational and its operating range is still greater than 40 miles per charge. It is too early to evaluate the life expectancy of the other three batteries, the Trojan T-145, Exide GC-5, and Alco 2200. No module has been replaced in these three packs. The Trojan T-145 battery is a very promising EV traction battery in terms of quality and reliability versus price. HNEI will keep the Trojan and Exide battery packs in operation. The Alco 2200 batteries will be transferred to another vehicle. The Additional Charging Method seems to be an effective way of restoring weak modules. The ``Smart Voltmeter`` developed by HNEI is a promising way of monitoring the remaining range for an EV.

1992-03-01T23:59:59.000Z

248

Modelling Thermodynamics of Alloys for Fusion Application  

SciTech Connect

This research has two main objectives: (1) The development of computational tools to evaluate alloy properties, using the information contained in thermodynamic functions. We aim at improving the ability of classical potentials to account for complex alloy behavior, and (2) The application of these tools to predict properties of alloys under irradiation, in particular the FeCr system. This semester has been very productive in the developments of both tools and algorithms. Our work aims at developing theoretical and numerical methodologies that are directly applicable to multi-scale modeling addressing the specific issues related to multi-component, multi-phase systems in non-equilibrium states, such as solid-solution hardening, point defect-solute interactions, stoichiometry effects, static and dynamic strain aging, dislocation-solute interactions, and in general the aspects of microstructure evolution that are affected by irradiation. At its present stage of development, we have been able to predict numerous thermodynamic properties of FeCr mainly related to ordering and precipitation; we have found new intermetallic phases and suggested the existence of a dependence of the solubility limit on the degree of order of the alloy. At present, we are studying dislocation mobility in the solid solution and the heterogeneous phase, and we are developing a new algorithm to perform Monte Carlo simulations inside the miscibility gap, a technique that will allow us to study interfacial energies and nucleation sizes. We develop a strategy to model radiation damage in FeCr alloys, system in which magnetism introduces an anomaly in the heat of formation of the solid solution that is at the basis of its unique behavior. Magnetism has implications for the precipitation of excess Cr in the a phase in the presence of heterogeneities. These complexities pose many challenges for atomistic (empirical) methods. To address such issues we develop a modified, many-body potential by rigorously fitting thermodynamic properties, including free energy. Multi-million atom displacement Monte Carlo simulations in the transmutation ensemble, using both our new potential and our new MC code, are able to predict properties of non equilibrium processes like heterogeneous precipitation, and dislocation - precipitate interactions, enabling the study of hardening and embrittlement under irradiation.

Caro, A; Erhart, P; de Caro, M S; Sadigh, B; Srinivasan, S G; Stukowski, A

2009-07-29T23:59:59.000Z

249

Characterization of Solid State Phase Transformation in Continuously Heated and Cooled Ferritic Weld Metal  

Science Conference Proceedings (OSTI)

Arc welding processes involve cooling rates that vary over a wide range (1-100 K/s). The final microstructire is thus a product of the heating and cooling cycles experienced by the weld in addition to the weld composition. It has been shown that the first phase to form under weld cooling conditions may not be that predicted by equilibrium calculations. The partitioning of different interstitial/substitutional alloying elements at high temperatures can dramatically affect the subsequent phase transformations. In order to understand the effect of alloying on phase transformation temperatures and final microstructures time-resolved X-ray diffraction technique has been successfully used for characterization. The work by Jacot and Rappaz on pearlitic steels provided insight into austenitization of hypoeutectic steels using a finite volume model. However there is very little work done on the effect of heating and cooling rates on the phase transformation paths in bainitic/martensitic steels and weld metals. Previous work on a weld with higher aluminum content, deposited with a FCAW-S process indicated that even at aluminum levels where the primary phase to solidify from liquid should be delta ferrite, non-equilibrium austenite was observed. The presence of inhomogeneity in composition of the parent microstructure has been attributed to differences in transformation modes, temperatures and microstructures in dual-phase, TRIP steels and ferritic welds. The objectives of the work included the identification of the stability regions of different phases during heating and cooling, differences in the effect of weld heating and cooling rates on the phase transformation temperatures, and the variation in phase fractions of austenite and ferrite in the two phase regions as a function of temperature. The base composition used for the present work is a Fe-1%Al-2%Mn-1%Ni-0.04%C weld metal. A pseudo-binary phase diagram shows the expected solidification path under equilibrium conditions. However, the effect of heating and cooling rates on the phase transformation path due to non-equilibrium partitioning of alloying elements cannot be predicted by equilibrium phase diagrams. Also, it is unclear if there is retention of delta ferrite to room temperature due to compositional or thermal effects. This would dramatically affect the austenite to ferrite transformation due to carbon and nitrogen enrichment in the austenite.

Narayana, B [Ohio State University, The, Columbus; Mills, Michael J. [Ohio State University, The, Columbus; Specht, Eliot D [ORNL; Santella, Michael L [ORNL; Babu, Sudarsanam Suresh [Ohio State University, The, Columbus

2010-12-01T23:59:59.000Z

250

approved_list  

NLE Websites -- All DOE Office Websites (Extended Search)

2-Sep-2000 2-Sep-2000 Exp # Spokesperson Title Days 634-2 Freedman Study of the 8B Neutrino Spectrum Through the 8B(b+)8Be(2a) Decay Chain-II 4 767-3 Rehm Decay Properties of Particle-Unbound States in 19Ne-III 4 827-2 Mueller Study of Unstable Osmium Nuclei by Coulomb Excitation 4 863X-2 Reviol Measurement of Evaporation Residues in the 40Ca+150Sm Reaction 2 876 Romoli Measurement of 17F Breakup Cross Section at the Barrier 4 877 Davids Drip-Line Decay Studies Around A = 76 5 879 Charity Non-Equilibrium Neutron Emission in Ni + Mo Reactions 5 880X Heinz Preparations Toward a Search for Super-Heavy Elements at ATLAS: Phase I 5 881 Kondev Radiative Capture and Fusion Dynamics in Cold Fusion 90Zr + 92Mo Reaction 7 882 Doyle Measurement of 3He to 4He Ratios in Isotopically Purified Helium 6 884 Miller

251

Materials Science and Engineering  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Materials Science and Engineering Materials Science and Engineering 1 Fe---Cr A lloys f or A dvanced N uclear E nergy A pplica9ons Ron S canon---equilibrium solutes introduced by mechanical alloying can segregate to grain b oundaries, p roducing

252

Weak maser emission of methyl formate toward Sagittarius B2(N) in the Green Bank Telescope PRIMOS Survey  

E-Print Network (OSTI)

A non-LTE radiative transfer treatment of cis-methyl formate (HCOOCH3) rotational lines is presented for the first time using a set of theoretical collisional rate coefficients. These coefficients have been computed in the temperature range 5-30 K by combining coupled-channel scattering calculations with a high accuracy potential energy surface for HCOOCH3-He. The results are compared to observations toward the Sagittarius B2(N) molecular cloud using the publicly available PRIMOS survey from the Green Bank Telescope. A total of 49 low-lying transitions of methyl formate, with upper levels below 25 K, are identified. These lines are found to probe a presumably cold (~30 K), moderately dense (~1e4 cm-3) and extended region surrounding Sgr B2(N). The derived column density of ~4e14 cm-2 is only a factor of ~10 larger than the column density of the trans conformer in the same source. Provided that the two conformers have the same spatial distribution, this result suggests that strongly non-equilibrium processes m...

Faure, Alexandre; Szalewicz, Krzysztof; Wiesenfeld, Laurent

2014-01-01T23:59:59.000Z

253

Weather in stellar atmosphere: the dynamics of mercury clouds in alpha Andromedae  

E-Print Network (OSTI)

The formation of long-lasting structures at the surfaces of stars is commonly ascribed to the action of strong magnetic fields. This paradigm is supported by observations of evolving cool spots in the Sun and active late-type stars, and stationary chemical spots in the early-type magnetic stars. However, results of our seven-year monitoring of mercury spots in non-magnetic early-type star alpha Andromedae show that the picture of magnetically-driven structure formation is fundamentally incomplete. Using an indirect stellar surface mapping technique, we construct a series of 2-D images of starspots and discover a secular evolution of the mercury cloud cover in this star. This remarkable structure formation process, observed for the first time in any star, is plausibly attributed to a non-equilibrium, dynamical evolution of the heavy-element clouds created by atomic diffusion and may have the same underlying physics as the weather patterns on terrestrial and giant planets.

Oleg Kochukhov; Saul J. Adelman; Austin F. Gulliver; Nikolai Piskunov

2007-05-30T23:59:59.000Z

254

Catastrophic cooling and cessation of heating in the solar corona  

E-Print Network (OSTI)

Condensations in the more than 10^6 K hot corona of the Sun are commonly observed in the extreme ultraviolet (EUV). While their contribution to the total solar EUV radiation is still a matter of debate, these condensations certainly provide a valuable tool for studying the dynamic response of the corona to the heating processes. We investigate different distributions of energy input in time and space to investigate which process is most relevant for understanding these coronal condensations. For a comparison to observations we synthesize EUV emission from a time-dependent, one-dimensional model for coronal loops, where we employ two heating scenarios: simply shutting down the heating and a model where the heating is very concentrated at the loop footpoints, while keeping the total heat input constant. The heating off/on model does not lead to significant EUV count rates that one observes with SDO/AIA. In contrast, the concentration of the heating near the footpoints leads to thermal non-equilibrium near the l...

Peter, H; Kamio, S

2011-01-01T23:59:59.000Z

255

Effective zero-thickness model for a conductive membrane driven by an electric field  

E-Print Network (OSTI)

The behavior of a conductive membrane in a static (DC) electric field is investigated theoretically. An effective zero-thickness model is constructed based on a Robin-type boundary condition for the electric potential at the membrane, originally developed for electrochemical systems. Within such a framework, corrections to the elastic moduli of the membrane are obtained, which arise from charge accumulation in the Debye layers due to capacitive effects and electric currents through the membrane and can lead to an undulation instability of the membrane. The fluid flow surrounding the membrane is also calculated, which clarifies issues regarding these flows sharing many similarities with flows produced by induced charge electro-osmosis (ICEO). Non-equilibrium steady states of the membrane and of the fluid can be effectively described by this method. It is both simpler, due to the zero thickness approximation which is widely used in the literature on fluid membranes, and more general than previous approaches. The predictions of this model are compared to recent experiments on supported membranes in an electric field.

Falko Ziebert; Martin Z. Bazant; David Lacoste

2009-11-05T23:59:59.000Z

256

Chandra Observations of the Eastern Limb of the Vela Supernova Remnant  

E-Print Network (OSTI)

We present results from two Chandra/ACIS observations of the so-called Vela ``Bullet D'' region on the eastern limb of the Vela supernova remnant. The Bullet D region is a bright X-ray feature, identified by Aschenbach et al. (1995) from the ROSAT All-Sky Survey, which protrudes beyond the blast wave on the eastern side of the remnant. It has been suggested that this feature is a fragment of supernova ejecta which is just now pushing beyond the position of the main blast wave. An alternate explanation is that the feature is a ``break-out'' of the shock in which inhomogeneities in the ambient medium cause the shock to be non-spherical. The Chandra image shows a fragmented, filamentary morphology within this region. The Chandra spectra show strong emission lines of O, Ne, and Mg. Equilibrium ionization models indicate that the O and Ne abundances are significantly enhanced compared to solar values. However, non-equilibrium ionization models can fit the data with solar O abundances and Ne abundances enhanced by only a factor of two. The Chandra data are more consistent with the shock breakout hypothesis, although they cannot exclude the fragment of ejecta hypothesis.

P. P. Plucinsky; R. K Smith; R. J. Edgar; T. J. Gaetz; P. O. Slane; W. P. Blair; L. K. Townsley; P. S. Broos

2001-12-12T23:59:59.000Z

257

A hybrid particle-continuum method for hydrodynamics of complex fluids  

E-Print Network (OSTI)

A previously-developed hybrid particle-continuum method [J. B. Bell, A. Garcia and S. A. Williams, SIAM Multiscale Modeling and Simulation, 6:1256-1280, 2008] is generalized to dense fluids and two and three dimensional flows. The scheme couples an explicit fluctuating compressible Navier-Stokes solver with the Isotropic Direct Simulation Monte Carlo (DSMC) particle method [A. Donev and A. L. Garcia and B. J. Alder, ArXiv preprint 0908.0510]. To achieve bidirectional dynamic coupling between the particle (microscale) and continuum (macroscale) regions, the continuum solver provides state-based boundary conditions to the particle subdomain, while the particle solver provides flux-based boundary conditions for the continuum subdomain. The equilibrium diffusive (Brownian) motion of a large spherical bead suspended in a particle fluid is examined, demonstrating that the hybrid method correctly reproduces the velocity autocorrelation function of the bead but only if thermal fluctuations are included in the continuum solver. Finally, the hybrid is applied to the well-known adiabatic piston problem and it is found that the hybrid correctly reproduces the slow non-equilibrium relaxation of the piston toward thermodynamic equilibrium but, again, only the continuum solver includes stochastic (white-noise) flux terms. These examples clearly demonstrate the need to include fluctuations in continuum solvers employed in hybrid multiscale methods.

A. Donev; J. B. Bell; A. L. Garcia; B. J. Alder

2009-10-20T23:59:59.000Z

258

Error suppression and error correction in adiabatic quantum computation I: techniques and challenges  

E-Print Network (OSTI)

Adiabatic quantum computation (AQC) is known to possess some intrinsic robustness, though it is likely that some form of error correction will be necessary for large scale computations. Error handling routines developed for circuit-model quantum computation do not transfer easily to the AQC model since these routines typically require high-quality quantum gates, a resource not generally allowed in AQC. There are two main techniques known to suppress errors during an AQC implementation: energy gap protection and dynamical decoupling. Here we show that both these methods are intimately related and can be analyzed within the same formalism. We analyze the effectiveness of such error suppression techniques and identify critical constraints on the performance of error suppression in AQC, suggesting that error suppression by itself is insufficient for large-scale, fault-tolerant AQC and that a form of error correction is needed. We discuss progress towards implementing error correction in AQC and enumerate several key outstanding problems. This work is a companion paper to "Error suppression and error correction in adiabatic quantum computation II: non-equilibrium dynamics"', which provides a dynamical model perspective on the techniques and limitations of error suppression and error correction in AQC. In this paper we discuss the same results within a quantum information framework, permitting an intuitive discussion of error suppression and correction in encoded AQC.

Kevin C. Young; Mohan Sarovar; Robin Blume-Kohout

2013-07-22T23:59:59.000Z

259

Effects of confining pressure, pore pressure and temperature on absolute permeability. SUPRI TR-27  

SciTech Connect

This study investigates absolute permeability of consolidated sandstone and unconsolidated sand cores to distilled water as a function of the confining pressure on the core, the pore pressure of the flowing fluid and the temperature of the system. Since permeability measurements are usually made in the laboratory under conditions very different from those in the reservoir, it is important to know the effect of various parameters on the measured value of permeability. All studies on the effect of confining pressure on absolute permeability have found that when the confining pressure is increased, the permeability is reduced. The studies on the effect of temperature have shown much less consistency. This work contradicts the past Stanford studies by finding no effect of temperature on the absolute permeability of unconsolidated sand or sandstones to distilled water. The probable causes of the past errors are discussed. It has been found that inaccurate measurement of temperature at ambient conditions and non-equilibrium of temperature in the core can lead to a fictitious permeability reduction with temperature increase. The results of this study on the effect of confining pressure and pore pressure support the theory that as confining pressure is increased or pore pressure decreased, the permeability is reduced. The effects of confining pressure and pore pressure changes on absolute permeability are given explicitly so that measurements made under one set of confining pressure/pore pressure conditions in the laboratory can be extrapolated to conditions more representative of the reservoir.

Gobran, B.D.; Ramey, H.J. Jr.; Brigham, W.E.

1981-10-01T23:59:59.000Z

260

Stationary electron velocity distribution function in crossed electric and magnetic fields with collisions  

Science Conference Proceedings (OSTI)

Analytical studies and numerical simulations show that the electron velocity distribution function in a Hall thruster discharge with crossed electric and magnetic fields is not Maxwellian. This is due to the fact that the mean free path between collisions is greater than both the Larmor radius and the characteristic dimensions of the discharge channel. However in numerical models of Hall thrusters, a hydrodynamic approach is often used to describe the electron dynamics, because discharge simulation in a fully kinetic approach requires large computing resources and is time consuming. A more accurate modeling of the electron flow in the hydrodynamic approximation requires taking into account the non-Maxwellian character of the distribution function and finding its moments, an approach that reflects the properties of electrons drifting in crossed electric and magnetic fields better than the commonly used Euler or Navier-Stokes approximations. In the present paper, an expression for the electron velocity distribution function in rarefied spatially homogeneous stationary plasma with crossed electric and magnetic fields and predominance of collisions with heavy particles is derived in the relaxation approximation. The main moments of the distribution function including longitudinal and transversal temperatures, the components of the viscous stress tensor, and of the heat flux vector are calculated. Distinctive features of the hydrodynamic description of electrons with a strongly non-equilibrium distribution function and the prospects for further development of the proposed approach for calculating the distribution function in spatially inhomogeneous plasma are discussed.

Shagayda, Andrey [Department of Electrophysics, Keldysh Research Centre, Moscow 125438 (Russian Federation)

2012-08-15T23:59:59.000Z

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261

One-dimensional hybrid-direct kinetic simulation of the discharge plasma in a Hall thruster  

SciTech Connect

In order to model the non-equilibrium plasma within the discharge region of a Hall thruster, the velocity distribution functions (VDFs) must be obtained accurately. A direct kinetic (DK) simulation method that directly solves the plasma Boltzmann equation can achieve better resolution of VDFs in comparison to particle simulations, such as the particle-in-cell (PIC) method that inherently include statistical noise. In this paper, a one-dimensional hybrid-DK simulation, which uses a DK simulation for heavy species and a fluid model for electrons, is developed and compared to a hybrid-PIC simulation. Time-averaged results obtained from the hybrid-DK simulation are in good agreement with hybrid-PIC results and experimental data. It is shown from a comparison of using a kinetic simulation and solving the continuity equation that modeling of the neutral atoms plays an important role for simulations of the Hall thruster discharge plasma. In addition, low and high frequency plasma oscillations are observed. Although the kinetic nature of electrons is not resolved due to the use of a fluid model, the hybrid-DK model provides spatially and temporally well-resolved plasma properties and an improved resolution of VDFs for heavy species with less statistical noise in comparison to the hybrid-PIC method.

Hara, Kentaro; Boyd, Iain D. [University of Michigan, Ann Arbor, Michigan 48109 (United States); Kolobov, Vladimir I. [CFD Research Corporation, Huntsville, Alabama 35805 (United States)

2012-11-15T23:59:59.000Z

262

Constraining the initial state granularity with bulk observables in Au+Au collisions at $\\sqrt{s_{\\rm NN}}=200$ GeV  

E-Print Network (OSTI)

In this paper we conduct a systematic study of the granularity of the initial state of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions and its influence on bulk observables like particle yields, $m_T$ spectra and elliptic flow. For our investigation we use a hybrid transport model, based on (3+1)d hydrodynamics and a microscopic Boltzmann transport approach. The initial conditions are generated by a non-equilibrium hadronic transport approach and the size of their fluctuations can be adjusted by defining a Gaussian smoothing parameter $\\sigma$. The dependence of the hydrodynamic evolution on the choices of $\\sigma$ and $t_{start}$ is explored by means of a Gaussian emulator. To generate particle yields and elliptic flow that are compatible with experimental data the initial state parameters are constrained to be $\\sigma=1$ fm and $t_{\\rm start}=0.5$ fm. In addition, the influence of changes in the equation of state is studied and the results of our event-by-event calculations are ...

Petersen, Hannah; Bass, Steffen A; Wolpert, Robert

2010-01-01T23:59:59.000Z

263

Rare-event trajectory ensemble analysis reveals metastable dynamical phases in lattice proteins  

E-Print Network (OSTI)

We explore the dynamical large-deviations of a lattice heteropolymer model of a protein by means of path sampling of trajectories. We uncover the existence of non-equilibrium dynamical phase-transitions in ensembles of trajectories between active and inactive dynamical phases, whose nature depends on properties of the interaction potential. When the full heterogeneity of interactions due to the amino-acid sequence is preserved, as in a fully interacting model or in a heterogeneous version of the G\\={o} model where only native interactions are considered, the transition is between the equilibrium native state and a highly native but kinetically trapped state. In contrast, for the homogeneous G\\={o} model, where there is a single native energy and the sequence plays no role, the dynamical transition is a direct consequence of the static bi-stability between unfolded and native states. In the heterogeneous case the native-active and native-inactive states, despite their static similarity, have widely varying dynamical properties, and the transition between them occurs even in lattice proteins whose sequences are designed to make them optimal folders.

Antonia S. J. S. Mey; Phillip L. Geissler; Juan P. Garrahan

2013-05-24T23:59:59.000Z

264

Radiation in molecular dynamic simulations  

DOE Green Energy (OSTI)

Hot dense radiative (HDR) plasmas common to Inertial Confinement Fusion (ICF) and stellar interiors have high temperature (a few hundred eV to tens of keV), high density (tens to hundreds of g/cc) and high pressure (hundreds of Megabars to thousands of Gigabars). Typically, such plasmas undergo collisional, radiative, atomic and possibly thermonuclear processes. In order to describe HDR plasmas, computational physicists in ICF and astrophysics use atomic-scale microphysical models implemented in various simulation codes. Experimental validation of the models used to describe HDR plasmas are difficult to perform. Direct Numerical Simulation (DNS) of the many-body interactions of plasmas is a promising approach to model validation but, previous work either relies on the collisionless approximation or ignores radiation. We present a new numerical simulation technique to address a currently unsolved problem: the extension of molecular dynamics to collisional plasmas including emission and absorption of radiation. The new technique passes a key test: it relaxes to a blackbody spectrum for a plasma in local thermodynamic equilibrium. This new tool also provides a method for assessing the accuracy of energy and momentum exchange models in hot dense plasmas. As an example, we simulate the evolution of non-equilibrium electron, ion, and radiation temperatures for a hydrogen plasma using the new molecular dynamics simulation capability.

Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M

2008-10-13T23:59:59.000Z

265

Constraining the initial state granularity with bulk observables in Au+Au collisions at $\\sqrt{s_{\\rm NN}}=200$ GeV  

E-Print Network (OSTI)

In this paper we conduct a systematic study of the granularity of the initial state of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions and its influence on bulk observables like particle yields, $m_T$ spectra and elliptic flow. For our investigation we use a hybrid transport model, based on (3+1)d hydrodynamics and a microscopic Boltzmann transport approach. The initial conditions are generated by a non-equilibrium hadronic transport approach and the size of their fluctuations can be adjusted by defining a Gaussian smoothing parameter $\\sigma$. The dependence of the hydrodynamic evolution on the choices of $\\sigma$ and $t_{start}$ is explored by means of a Gaussian emulator. To generate particle yields and elliptic flow that are compatible with experimental data the initial state parameters are constrained to be $\\sigma=1$ fm and $t_{\\rm start}=0.5$ fm. In addition, the influence of changes in the equation of state is studied and the results of our event-by-event calculations are compared to a calculation with averaged initial conditions. We conclude that even though the initial state parameters can be constrained by yields and elliptic flow, the granularity needs to be constrained by other correlation and fluctuation observables.

Hannah Petersen; Christopher Coleman-Smith; Steffen A. Bass; Robert Wolpert

2010-12-21T23:59:59.000Z

266

Out-of-Equilibrium Chiral Magnetic Effect at Strong Coupling  

E-Print Network (OSTI)

We study the charge transports originating from triangle anomaly in out-of-equilibrium conditions in the framework of AdS/CFT correspondence at strong coupling, to gain useful insights on possible charge separation effects that may happen in the very early stages of heavy-ion collisions. We first construct a gravity background of a homogeneous mass shell with a finite (axial) charge density gravitationally collapsing to a charged blackhole, which serves as a dual model for out-of-equilibrium charged plasma undergoing thermalization. We find that a finite charge density in the plasma slows down the thermalization. We then study the out-of-equilibrium properties of Chiral Magnetic Effect and Chiral Magnetic Wave in this background. As the medium thermalizes, the magnitude of chiral magnetic conductivity and the response time delay grow. We find a dynamical peak in the spectral function of retarded current correlator, which we identify as an out-of-equilibrium chiral magnetic wave. The group velocity of the out-of-equilibrium chiral magnetic wave is shown to receive a dominant contribution from a non-equilibrium effect, making the wave moving much faster than in the equilibrium, which may enhance the charge transports via triangle anomaly in the early stage of heavy-ion collisions.

Shu Lin; Ho-Ung Yee

2013-05-16T23:59:59.000Z

267

Lattice-gas model for active vesicle transport by molecular motors with opposite polarities  

E-Print Network (OSTI)

We introduce a multi-species lattice gas model for motor protein driven collective cargo transport on cellular filaments. We use this model to describe and analyze the collective motion of interacting vesicle cargoes being carried by oppositely directed molecular motors, moving on a single biofilament. Building on a totally asymmetric exclusion process (TASEP) to characterize the motion of the interacting cargoes, we allow for mass exchange with the environment, input and output at filament boundaries and focus on the role of interconversion rates and how they affect the directionality of the net cargo transport. We quantify the effect of the various different competing processes in terms of non-equilibrium phase diagrams. The interplay of interconversion rates, which allow for flux reversal and evaporation/deposition processes introduce qualitatively new features in the phase diagrams. We observe regimes of three-phase coexistence, the possibility of phase re-entrance and a significant flexibility in how the different phase boundaries shift in response to changes in control parameters. The moving steady state solutions of this model allows for different possibilities for the spatial distribution of cargo vesicles, ranging from homogeneous distribution of vesicles to polarized distributions, characterized by inhomogeneities or {\\it shocks}. Current reversals due to internal regulation emerge naturally within the framework of this model. We believe this minimal model will clarify the understanding of many features of collective vesicle transport, apart from serving as the basis for building more exact quantitative models for vesicle transport relevant to various {\\it in-vivo} situations.

Sudipto Muhuri; Ignacio Pagonabarraga

2010-09-09T23:59:59.000Z

268

Small hydrocarbon molecules in cloud-forming Brown Dwarf and giant gas planet atmospheres  

E-Print Network (OSTI)

We study the abundances of complex carbon-bearing molecules in the oxygen-rich dust- forming atmospheres of Brown Dwarfs and giant gas planets. The inner atmospheric re- gions that form the inner boundary for thermochemical gas-phase models are investigated. Results from Drift-phoenix atmosphere simulations, which include the feedback of phase- non-equilibrium dust cloud formation on the atmospheric structure and the gas-phase abun- dances, are utilised. The resulting element depletion leads to a shift in the carbon-to-oxygen ratio such that several hydrocarbon molecules and cyanopolycyanopolyynene molecules can be present. An increase in surface gravity and/or a decrease in metallicity support the increase in the partial pressures of these species. CO, CO2, CH4, and HCN contain the largest fraction of carbon. In the upper atmosphere of low-metallicity objects, more carbon is contained in C4H than in CO, and also CH3 and C2H2 play an increasingly important role as carbon-sink. We determine chemical relaxation...

Bilger, Camille; Helling, Christiane

2013-01-01T23:59:59.000Z

269

Nitrogen-Doped Graphitic Nanoribbons: Synthesis, Characterization and Transport  

SciTech Connect

Nitrogen-doped graphitic nanoribbons (Nx-GNRs), synthesized by chemical vapor deposition (CVD) using pyrazine as a nitrogen precursor, are reported for the first time. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) reveal that the synthesized materials are formed by multi-layered corrugated graphitic nanoribbons (GNRs) which in most cases exhibit the formation of curved graphene edges (loops). This suggests that during growth, nitrogen atoms promote loop formation; undoped GNRs do not form loops at their edges. Transport measurements on individual pure carbon GNRs exhibit a linear I-V (current-voltage) behavior, whereas Nx-GNRs show reduced current responses following a semiconducting-like behavior, which becomes more prominent for high nitrogen concentrations. To better understand the experimental findings, electron density of states (DOS), quantum conductance for nitrogen doped zigzag and armchair single-layer GNRs are calculated for different N doping concentrations using Density Functional Theory (DFT) and non-equilibrium Green functions. These calculations confirm the crucial role of nitrogen atoms in the transport properties, confirming that the nonlinear I-V curves are due to the presence of nitrogen atoms within the Nx-GNRs lattice that act as scattering sites. These characteristic Nx-GNRs transport could be advantageous in the fabrication of electronic devices including sensors in which metal-like undoped GNRs are unsuitable.

Jia, Xiaoting [Massachusetts Institute of Technology (MIT); Dresselhaus, M [Massachusetts Institute of Technology (MIT); Cruz Silva, Eduardo [ORNL; Munoz-Sandoval, E [Instituto de Microelectronica de Madrid (CNM, CSIC); Sumpter, Bobby G [ORNL; Terrones Maldonado, Humberto [ORNL; Terrones Maldonado, Humberto [ORNL; Lopez, Florentino [IPICyT

2013-01-01T23:59:59.000Z

270

AN EXPERIMENTAL AND THEORETICAL STUDY OF THE IONIZATION ENERGIES OF SiC{sub 2}H{sub x} (x = 0, 1, 2) ISOMERS  

SciTech Connect

We present a combined experimental and theoretical study on the formation processes and ionization energies of small organo-silicon molecules of the formula SiC{sub 2}H{sub x} (x = 0, 1, 2). These organic molecules are considered important benchmark systems in understanding the formation of silicon- and carbon-bearing grains in the outflow of carbon stars. The studies identify four distinct (hydrogenated) silicon-carbon molecules together with their ionization energies: c-SiC{sub 2} [9.75 {+-} 0.10 eV; 9.83 {+-} 0.05 eV], l-HCCSi [7.00 {+-} 0.05 eV], c-SiC{sub 2}H [7.27 {+-} 0.05 eV], and c-SiC{sub 2}H{sub 2} [9.05 {+-} 0.05 eV; 8.96 {+-} 0.05 eV] with numbers in italics depicting computed data. Implications of these results to the non-equilibrium chemistry in shocked regions of circumstellar envelopes of carbon stars are also discussed.

Kaiser, Ralf I. [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Krishtal, Sergey P.; Mebel, Alexander M. [Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199 (United States); Kostko, Oleg; Ahmed, Musahid [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2012-12-20T23:59:59.000Z

271

Mesophases in polyethylene, polypropylene, and poly(1-butene)  

Science Conference Proceedings (OSTI)

This paper contains new views about the amorphous and partially ordered phases of the three polymers listed in the title. The discussion is based on information on structure, thermodynamic stability, and large-amplitude molecular motion. Polyethylene is the basic backbone of all alkene polymers, and the other two are the first members of the vinyl polymers which have stereospecifically placed alkyl side chains. Their multiphase structures consist of metastable crystals, mesophases, and surrounding rigid and mobile amorphous fractions. All these phases have sizes ranging from micrometer dimensions down to nanometers. Besides the phase structures, information about the molecular coupling between the phases must be considered. Depending on temperature, the polymer phases can vary from solid (rigid) to liquid (mobile). New knowledge is also gained by cross-comparison of the title polymers. The experimental information was gained from (a) various forms of slow, fast, and temperature-modulated thermal analysis to identify equilibrium and non-equilibrium states, (b) measurement of structure and morphology at various length scales, and (c) tracing of the large-amplitude molecular motion, the kinetics of order/disorder changes, and the liquid/solid transitions (glass transitions). It is shown that much more needs to be known about the various phases and their coupling to characterize a given polymer and to fine-tune its properties for a given application.

Androsch, Rene J [ORNL; Di Lorenzo, Maria [ORNL; Schick, Christoph [Rostock University, Rostock, Germany; Wunderlich, Bernhard {nmn} [ORNL

2010-01-01T23:59:59.000Z

272

Materials processing with intense pulsed ion beams  

SciTech Connect

We review research investigating the application of intense pulsed ion beams (IPIBs) for the surface treatment and coating of materials. The short range (0.1-10 {mu}m) and high-energy density (1-50 J/cm{sup 2}) of these short-pulsed ({le} 1 {mu}s) beams (with ion currents I = 5 - 50 kA, and energies E = 100 - 1000 keV) make them ideal to flash-heat a target surface, similar to the more familiar pulsed laser processes. IPIB surface treatment induces rapid melt and solidification at up to 10{sup 10} K/s to cause amorphous layer formation and the production of non-equilibrium microstructures. At higher energy density the target surface is vaporized, and the ablated vapor is condensed as coatings onto adjacent substrates or as nanophase powders. Progress towards the development of robust, high-repetition rate IPIB accelerators is presented along with economic estimates for the cost of ownership of this technology.

Rej, D.J.; Davis, H.A.; Olson, J.C. [and others

1996-12-31T23:59:59.000Z

273

Ion beam surface treatment: A new capability for surface enhancement  

Science Conference Proceedings (OSTI)

The emerging capability to produce high average power (5--350 kW) pulsed ion beams at 0.2--2 MeV energies is enabling the authors to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This new technique uses high energy, pulsed ({<=}250 ns) ion beams to directly deposit energy in the top 2--20 micrometers of the surface of any material. The depth of treatment is controllable by varying the ion energy and species. Deposition of the energy with short pulses in a thin surface layer allows melting of the layer with relatively small energies and allows rapid cooling of the melted layer by thermal diffusion into the underlying substrate. Typical cooling rates of this process (10{sup 9}--10{sup 10} K/sec) cause rapid resolidification, resulting in the production of non-equilibrium microstructures (nano-crystalline and metastable phases) that have significantly improved corrosion, wear, and hardness properties. The authors conducted IBEST feasibility experiments with results confirming surface hardening, noncrystalline grain formation, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning using pulsed ion beams.

Stinnett, R.W.; McIntyre, D.C.; Buchheit, R.G.; Neau, E.L. [Sandia National Labs., Albuquerque, NM (United States); Greenly, J.B.; Thompson, M.O. [Cornell Univ., Ithaca, NY (United States); Johnston, G.P. [Univ. of New Mexico, Albuquerque, NM (United States); Rej, D.J. [Los Alamos National Lab., NM (United States)

1994-07-01T23:59:59.000Z

274

Ion beam surface treatment: A new capability for rapid melt and resolidification of surfaces  

Science Conference Proceedings (OSTI)

The emerging capability to produce high average power (5--250 kW) pulsed ion beams at 0.2--2 MeV energies is enabling us to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This technique uses high energy, pulsed ({le}100 ns) ion beams to directly deposit energy in the top 2--20 micrometers of the surface of any material. Depth of treatment is controllable by varying the ion energy and species. Deposition of the energy with short pulses in a thin surface layer allows melting of the layer with relatively small energies and allows rapid cooling of the melted layer by thermal diffusion into the underlying substrate. Typical cooling rates of this process (10{sup 9}10{sup 10} K/sec) cause rapid resolidification, resulting in production of non-equilibrium microstructures (nano-crystalline and metastable phases) that have significantly improved corrosion, wear, and hardness properties. We have conducted IBEST feasibility experiments with results confirming surface hardening, nanocrystaline grain formation, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning.

Stinnett, R.W.; McIntyre, D.C.; Buchheit, R.G. [Sandia National Labs., Albuquerque, NM (United States); Greenly, J.B.; Thompson, M.O. [Cornell Univ., Ithaca, NY (United States)

1994-04-01T23:59:59.000Z

275

Functionalized nanopore-embedded electrodes for rapid DNA sequencing  

E-Print Network (OSTI)

The determination of a patient's DNA sequence can, in principle, reveal an increased risk to fall ill with particular diseases [1,2] and help to design "personalized medicine" [3]. Moreover, statistical studies and comparison of genomes [4] of a large number of individuals are crucial for the analysis of mutations [5] and hereditary diseases, paving the way to preventive medicine [6]. DNA sequencing is, however, currently still a vastly time-consuming and very expensive task [4], consisting of pre-processing steps, the actual sequencing using the Sanger method, and post-processing in the form of data analysis [7]. Here we propose a new approach that relies on functionalized nanopore-embedded electrodes to achieve an unambiguous distinction of the four nucleic acid bases in the DNA sequencing process. This represents a significant improvement over previously studied designs [8,9] which cannot reliably distinguish all four bases of DNA. The transport properties of the setup investigated by us, employing state-of-the-art density functional theory together with the non-equilibrium Green's Function method, leads to current responses that differ by at least one order of magnitude for different bases and can thus provide a much more robust read-out of the base sequence. The implementation of our proposed setup could thus lead to a viable protocol for rapid DNA sequencing with significant consequences for the future of genome related research in particular and health care in general.

Haiying He; Ralph H. Scheicher; Ravindra Pandey; Alexandre Reily Rocha; Stefano Sanvito; Anton Grigoriev; Rajeev Ahuja; Shashi P. Karna

2007-08-29T23:59:59.000Z

276

3.205 Thermodynamics and Kinetics of MaterialsFall 2006  

E-Print Network (OSTI)

The theory of nucleation kinetics is closely linked with fluctuation theory and the theory of activated processes. The steady-state nucleation rate, J, is the rate of formation of supercritical nuclei that form per unit volume, and it has the form J = Z?cNexp[??Gc/(kT)], where N is the number of available sites for nucleation, Z is called the Zeldovich non-equilibrium factor and is approximately 10 ?1, ?c is a term that relates to the diffusivity of atoms to a subcritical nucleus, and ?Gc is the free-energy barrier that needs to be overcome to form a critical nucleus. Using typical values of N, Z, and ?c, and assuming a reasonable value for a minimum detectable nucleation rate, one can show that ?Gc must be less than about 76kT for observable nucleation. ?Gc plays a critical role in nucleation kinetics. It is typically strongly dependent on undercooling and on interphase boundary structure. In solids, interfacial structure may be incoherent, semi-coherent, or coherent. Coherent interfaces have the lowest ?, on the order of 100 mJ/m 2, and are thus more likely at the nucleation stage. Coherent particles that form in systems in which the molar volume of the nucleus and the matrix differ also can have an elastic strain energy ?g? that impedes nucleation. Heterogeneous nucleation uses pre-existing imperfections to lower ?Gc for nucleation on special sites. Competition between homogeneous and heterogeneous nucleation is easily understood with the

unknown authors

2006-01-01T23:59:59.000Z

277

A GENERALIZED MODEL OF NONLINEAR DIFFUSIVE SHOCK ACCELERATION COUPLED TO AN EVOLVING SUPERNOVA REMNANT  

Science Conference Proceedings (OSTI)

To better model the efficient production of cosmic rays (CRs) in supernova remnants (SNRs) with the associated coupling between CR production and SNR dynamics, we have generalized an existing cr-hydro-NEI code to include the following processes: (1) an explicit calculation of the upstream precursor structure including the position-dependent flow speed, density, temperature, and magnetic field strength; (2) a momentum- and space-dependent CR diffusion coefficient; (3) an explicit calculation of magnetic field amplification; (4) calculation of the maximum CR momentum using the amplified magnetic field; (5) a finite Alfven speed for the particle scattering centers; and (6) the ability to accelerate a superthermal seed population of CRs, as well as the ambient thermal plasma. While a great deal of work has been done modeling SNRs, most work has concentrated on either the continuum emission from relativistic electrons or ions or the thermal emission from the shock heated plasma. Our generalized code combines these elements and describes the interplay between CR production and SNR evolution, including the nonlinear coupling of efficient diffusive shock acceleration, based mainly on the work of P. Blasi and coworkers, and a non-equilibrium ionization (NEI) calculation of thermal X-ray line emission. We believe that our generalized model will provide a consistent modeling platform for SNRs, including those interacting with molecular clouds, and improve the interpretation of current and future observations, including the high-quality spectra expected from Astro-H. SNR RX J1713.7-3946 is modeled as an example.

Lee, Shiu-Hang; Nagataki, Shigehiro [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Ellison, Donald C., E-mail: lee@yukawa.kyoto-u.ac.jp, E-mail: nagataki@yukawa.kyoto-u.ac.jp, E-mail: don_ellison@ncsu.edu [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States)

2012-05-10T23:59:59.000Z

278

Modeling ramp compression experiments using large-scale molecular dynamics simulation.  

Science Conference Proceedings (OSTI)

Molecular dynamics simulation (MD) is an invaluable tool for studying problems sensitive to atomscale physics such as structural transitions, discontinuous interfaces, non-equilibrium dynamics, and elastic-plastic deformation. In order to apply this method to modeling of ramp-compression experiments, several challenges must be overcome: accuracy of interatomic potentials, length- and time-scales, and extraction of continuum quantities. We have completed a 3 year LDRD project with the goal of developing molecular dynamics simulation capabilities for modeling the response of materials to ramp compression. The techniques we have developed fall in to three categories (i) molecular dynamics methods (ii) interatomic potentials (iii) calculation of continuum variables. Highlights include the development of an accurate interatomic potential describing shock-melting of Beryllium, a scaling technique for modeling slow ramp compression experiments using fast ramp MD simulations, and a technique for extracting plastic strain from MD simulations. All of these methods have been implemented in Sandia's LAMMPS MD code, ensuring their widespread availability to dynamic materials research at Sandia and elsewhere.

Mattsson, Thomas Kjell Rene; Desjarlais, Michael Paul; Grest, Gary Stephen; Templeton, Jeremy Alan; Thompson, Aidan Patrick; Jones, Reese E.; Zimmerman, Jonathan A.; Baskes, Michael I. (University of California, San Diego); Winey, J. Michael (Washington State University); Gupta, Yogendra Mohan (Washington State University); Lane, J. Matthew D.; Ditmire, Todd (University of Texas at Austin); Quevedo, Hernan J. (University of Texas at Austin)

2011-10-01T23:59:59.000Z

279

Pulsed Corona Plasma Technology for Treating VOC Emissions from Pulp Mills  

DOE Green Energy (OSTI)

Under the DOE Office of Industrial Technologies Forest Products program various plasma technologies were evaluated under project FWP 49885 ''Experimental Assessment of Low-Temperature Plasma Technologies for Treating Volatile Organic Compound Emissions from Pulp Mills and Wood Products Plants''. The heterogeneous pulsed corona discharge was chosen as the best non-equilibrium plasma technology for control of the vent emissions from HVLC Brownstock Washers. The technology for removal of Volatile Organic Compounds (VOCs) from gas emissions with conditions typical of the exhausts of the paper industry by means of pulsed corona plasma techniques presented in this work. For the compounds of interest in this study (methanol, acetone, dimethyl sulfide and ? -pinene), high removal efficiencies were obtained with power levels competitive with the present technologies for the VOCs removal. Laboratory experiments were made using installation with the average power up to 20 W. Pilot plant prepared for on-site test has average plasma power up to 6.4 kW. The model of the Pilot Plant operation is presented.

Fridman, Alexander A.; Gutsol, Alexander; Kennedy, Lawrence A.; Saveliev, Alexei V.; Korobtsev, Sergey V.; Shiryaevsky, Valery L.; Medvedev, Dmitry

2004-07-28T23:59:59.000Z

280

Studying Complexity in Solar Wind Plasma During Shock Events. Part I: Nonextensive Tsallis Statistics  

E-Print Network (OSTI)

Novel results which reveal phase transition processes in the solar wind plasma during shock events are presented in this study which is the first part of a trilogy concerning the solar wind complexity. Solar wind plasma is a typical case of stochastic spatiotemporal distribution of physical magnitudes such as force fields (B, E) and matter fields (particle and current densities or bulk plasma distributions). The results of this study can be understood in the framework of modern theoretical concepts such as non-extensive statistical mechanics (Tsallis, 2009), fractal topology (Zelenyi and Milovanov, 2004), turbulence theory (Frisch,1996), strange dynamics (Zaslavsky, 2002), percolation theory (Milovanov, 1997), anomalous diffusion theory and anomalous transport theory (Milovanov, 2001), fractional dynamics (Tarasov, 2007) and non-equilibrium phase transition theory (Chang, 1992). This study shows clearly the non-extensive and non-Gaussian character of the solar wind plasma and the existence of multi-scale strong correlations from the microscopic to the macroscopic level. This result indicates the inefficiency of classical MHD or plasma statistical theories based on the classical central limit theorem to explain the complexity of the solar wind dynamics, since these theories include smooth and differentiable spatial-temporal functions (MHD theory) or Gaussian statistics (Boltzmann-Maxwell statistical mechanics). However, the results of this study indicate the presence of non-Gaussian non-extensive statistics with heavy tails probability distribution functions, which are related to the q-extension of central limit theorem.

G. P. Pavlos; A. C. Iliopoulos; G. N. Zastenker; L. M. Zelenyi; L. P. Karakatsanis; M. Riazantseva; M. N. Xenakis; E. G. Pavlos

2013-10-01T23:59:59.000Z

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281

Corresponding states for mesostructure and dynamics of supercooled water  

E-Print Network (OSTI)

Water famously expands upon freezing, foreshadowed by a negative coefficient of expansion of the liquid at temperatures close to its freezing temperature. These behaviors, and many others, reflect the energetic preference for local tetrahedral arrangements of water molecules and entropic effects that oppose it. Here, we provide theoretical analysis of mesoscopic implications of this competition, both equilibrium and non-equilibrium, including mediation by interfaces. With general scaling arguments bolstered by simulation results, and with reduced units that elucidate corresponding states, we derive a phase diagram for bulk and confined water and water-like materials. For water itself, the corresponding states cover the temperature range of 150 K to 300 K and the pressure range of 1 bar to 2 kbar. In this regime, there are two reversible condensed phases - ice and liquid. Out of equilibrium, there is irreversible polyamorphism, i.e., more than one glass phase, reflecting dynamical arrest of coarsening ice. Temperature-time plots are derived to characterize time scales of the different phases and explain contrasting dynamical behaviors of different water-like systems.

David T. Limmer; David Chandler

2013-05-07T23:59:59.000Z

282

Equilibrium thermodynamics in modified gravitational theories  

E-Print Network (OSTI)

We show that it is possible to obtain a picture of equilibrium thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density $f(R, \\phi, X)$, where $R$ is the Ricci scalar and $X$ is the kinetic energy of a scalar field $\\phi$. This comes from a suitable definition of an energy momentum tensor of the "dark" component that respects to a local energy conservation in the Jordan frame. In this framework the horizon entropy $S$ corresponding to equilibrium thermodynamics is equal to a quarter of the horizon area $A$ in units of gravitational constant $G$, as in Einstein gravity. For a flat cosmological background with a decreasing Hubble parameter, $S$ globally increases with time, as it happens for viable $f(R)$ inflation and dark energy models. We also show that the equilibrium description in terms of the horizon entropy $S$ is convenient because it takes into account the contribution of both the horizon entropy $\\hat{S}$ in non-equilibrium thermodynamics and an entropy production term.

Kazuharu Bamba; Chao-Qiang Geng; Shinji Tsujikawa

2009-09-11T23:59:59.000Z

283

X-RAY EMISSION FROM AN ASYMMETRIC BLAST WAVE AND A MASSIVE WHITE DWARF IN THE GAMMA-RAY EMITTING NOVA V407 Cyg  

SciTech Connect

Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equilibrium and non-equilibrium ionization plasmas at the time of peak X-ray brightness, indicating a strong asymmetry in the density of the emitting region. Comparing a simple model to the data, we find that the X-ray evolution is broadly consistent with nova ejecta driving a forward shock into the dense wind of the Mira companion. We detect a highly absorbed soft X-ray component in the spectrum during the first 50 days of the outburst that is consistent with supersoft emission from the nuclear burning white dwarf. The high temperature and short turnoff time of this emission component, in addition to the observed breaks in the optical and UV light curves, indicate that the white dwarf in the binary is extremely massive. Finally, we explore the connections between the X-ray and GeV {gamma}-ray evolution, and propose that the gamma-ray turnoff is due to the stalling of the forward shock as the ejecta reach the red giant surface.

Nelson, Thomas; Donato, Davide; Mukai, Koji [CRESST and X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States); Sokoloski, Jennifer [Columbia Astrophysics Laboratory, 550 W. 220th Street, 1027 Pupin Hall, Columbia University, New York, NY 10027 (United States); Chomiuk, Laura, E-mail: tnelson@physics.umn.ed [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-03-20T23:59:59.000Z

284

Phase transitions in the early and the present Universe  

E-Print Network (OSTI)

The evolution of the Universe is the ultimate laboratory to study fundamental physics across energy scales that span about 25 orders of magnitude: from the grand unification scale through particle and nuclear physics scales down to the scale of atomic physics. The standard models of cosmology and particle physics provide the basic understanding of the early and present Universe and predict a series of phase transitions that occurred in succession during the expansion and cooling history of the Universe. We survey these phase transitions, highlighting the equilibrium and non-equilibrium effects as well as their observational and cosmological consequences. We discuss the current theoretical and experimental programs to study phase transitions in QCD and nuclear matter in accelerators along with the new results on novel states of matter as well as on multi- fragmentation in nuclear matter. A critical assessment of similarities and differences between the conditions in the early universe and those in ultra- relativistic heavy ion collisions is presented. Cosmological observations and accelerator experiments are converging towards an unprecedented understanding of the early and present Universe.

D. Boyanovsky; H. J. de Vega; D. J. Schwarz

2006-02-01T23:59:59.000Z

285

Thermal instability in the collisionally cooled gas  

E-Print Network (OSTI)

We have presented the non-equilibrium (time-dependent) cooling rate and ionization state calculations for a gas behind shock waves with $v \\sim 50-150$ km s$^{-1}$ ($T_s \\sim 0.5 - 6\\times 10^5$ K). Such shock waves do not lead to the radiative precursor formation, i.e. the thermal evolution of a gas behind the shock waves are controlled by collisions only. We have found that the cooling rate in a gas behind the shock waves with $v \\sim 50-120$ km s$^{-1}$ ($T_s \\sim 0.5 - 3\\times 10^5$ K) differs considerably from the cooling rate for a gas cooled from $T = 10^8$ K. It is well-known that a gas cooled from $T = 10^8$ K is thermally unstable for isobaric and isochoric perturbations at $T \\simgt 2\\times 10^4$ K. We have studied the thermal instability in a collisionally controlled gas for shock waves with $v \\sim 50-150$ km s$^{-1}$. We have found that the temperature range, where the postshock gas is thermally unstable, is significantly modified and depends on both gas metallicity and ionic composition of a ga...

Vasiliev, Evgenii O

2011-01-01T23:59:59.000Z

286

Reactivity transients during a blowdown in a MSIV (Main Steam Isolation Valves) closure ATWS (Anticipated Transients Without Scram)  

SciTech Connect

The objectives of this work are to study the consequences of the reactivity transients during a blowdown in an ATWS event with closure of the Main Steam Isolation Valves (MSIV), and to evaluate the effect of the LPCI (Low Pressure Coolant Injection) system and the sensitivity of plant response to the feedback coefficients. The present work was performed with the BNL Plant Analyzer (BPA). The BPA is a on-line, interactive BWR system code which models the non-homogeneous, non-equilibrium two-phase flow with a drift flux mixture model, the reactor kinetics with a point kinetic model, the thermal conduction with an integral method, and the control and plant protection systems with modern control theory. It also models the balance of plant (BOP) as well as the Mark I containment of a BWR/4. Thus, the BPA is a comprehensive engineering plant analyzer transients as well as accidents (e.g., ATWS and Small Break Loss of Coolant Accidents).

Cheng, H.S.; Diamond, D.J.

1988-01-01T23:59:59.000Z

287

CRYSTALLIZATION IN HIGH-LEVEL WASTE GLASSES U.S. DEPARTMENT OF ENERGY OFFICE OF RIVER PROTECTION WTP ENGINEERING DIVISION  

SciTech Connect

Various circumstances influence crystallization in glassmaking, for example: (1) crystals nucleate and grow before the glass-forming melt occurs; (2) crystals grow or dissolve in flowing melt and during changing temperature; (3) crystals move under the influence of gravity; (4) crystals agglomerate and interact with gas bubbles; (5) high-level wastes (HLW) are mixtures of a large number of components in unusual proportions; (6) melter processing of HLW and the slow cooling of HLW glass in canisters provides an opportunity for a variety of crystalline forms to precipitate; (7) settling of crystals in a HLW glass melter may produce undesirable sludge at the melter bottom; and (8) crystallization of the glass product may increase, but also ruin chemical durability. The conclusions are: (1) crystal growth and dissolution typically proceed in a convective medium at changing temperature; (2) to represent crystallization or dissolution the kinetics must be expressed in the form of rate equations, such as dC/dt = f(C,T) and the temperature dependence of kinetic coefficients and equilibrium concentrations must be accounted for; and (3) non-equilibrium phenomena commonly occur - metastable crystallization, periodic distribution of crystals; and dendritic crystal growth.

KRUGER AA; HRMA PR

2009-08-19T23:59:59.000Z

288

Blowdown of hydrocarbons pressure vessel with partial phase separation  

E-Print Network (OSTI)

We propose a model for the simulation of the blowdown of vessels containing two-phase (gas-liquid) hydrocarbon fluids, considering non equilibrium between phases. Two phases may be present either already at the beginning of the blowdown process (for instance in gas-liquid separators) or as the liquid is formed from flashing of the vapor due to the cooling induced by pressure decrease. There is experimental evidence that the assumption of thermodynamic equilibrium is not appropriate, since the two phases show an independent temperature evolution. Thus, due to the greater heat transfer between the liquid phase with the wall, the wall in contact with the liquid experiences a stronger cooling than the wall in contact with the gas, during the blowdown. As a consequence, the vessel should be designed for a lower temperature than if it was supposed to contain vapor only. Our model is based on a compositional approach, and it takes into account internal heat and mass transfer processes, as well as heat transfer with ...

Speranza, Alessandro; 10.1142/9789812701817_0046

2011-01-01T23:59:59.000Z

289

Advanced turbine design for coal-fueled engines  

DOE Green Energy (OSTI)

The objective of this task is to perform a technical assessment of turbine blading for advanced second generation PFBC conditions, identify specific problems/issues, and recommend an approach for solving any problems identified. A literature search was conducted, problems associated with hot corrosion defined and limited experiments performed. Sulfidation corrosion occurs in industrial, marine and aircraft gas turbine engines and is due to the presence of condensed alkali (sodium) sulfates. The principle source of the alkali in industrial, marine and aircraft gas turbine engines is sea salt crystals. The principle source of the sulfur is not the liquid fuels, but the same ocean born crystals. Moreover deposition of the corrosive salt occurs primarily by a non-equilibrium process. Sodium will be present in the cleaned combusted gases that enter the PFBC turbine. Although equilibrium condensation is not favored, deposition via impaction is probable. Marine gas turbines operate in sodium chloride rich environments without experiencing the accelerated attack noted in coal fired boilers where condensed chlorides contact metallic surfaces. The sulfates of calcium and magnesium are the products of the reactions used to control sulfur. Based upon industrial gas turbine experience and laboratory tests, calcium and magnesium sulfates are, at temperatures up to 1500[degrees]F (815[degrees]C), relatively innocuous salts. In this study it is found that at 1650[degrees]F (900[degrees]C) and above, calcium sulfate becomes an aggressive corrodent.

Bornstein, N.S.

1992-07-17T23:59:59.000Z

290

Advanced turbine design for coal-fueled engines. Topical report, Task 1.6, Task 1.7  

DOE Green Energy (OSTI)

The objective of this task is to perform a technical assessment of turbine blading for advanced second generation PFBC conditions, identify specific problems/issues, and recommend an approach for solving any problems identified. A literature search was conducted, problems associated with hot corrosion defined and limited experiments performed. Sulfidation corrosion occurs in industrial, marine and aircraft gas turbine engines and is due to the presence of condensed alkali (sodium) sulfates. The principle source of the alkali in industrial, marine and aircraft gas turbine engines is sea salt crystals. The principle source of the sulfur is not the liquid fuels, but the same ocean born crystals. Moreover deposition of the corrosive salt occurs primarily by a non-equilibrium process. Sodium will be present in the cleaned combusted gases that enter the PFBC turbine. Although equilibrium condensation is not favored, deposition via impaction is probable. Marine gas turbines operate in sodium chloride rich environments without experiencing the accelerated attack noted in coal fired boilers where condensed chlorides contact metallic surfaces. The sulfates of calcium and magnesium are the products of the reactions used to control sulfur. Based upon industrial gas turbine experience and laboratory tests, calcium and magnesium sulfates are, at temperatures up to 1500{degrees}F (815{degrees}C), relatively innocuous salts. In this study it is found that at 1650{degrees}F (900{degrees}C) and above, calcium sulfate becomes an aggressive corrodent.

Bornstein, N.S.

1992-07-17T23:59:59.000Z

291

From Clarkia to Escherichia and Janus: the physics of natural and synthetic active colloids  

E-Print Network (OSTI)

An active colloid is a suspension of particles that transduce free energy from their environment and use the energy to engage in intrinsically non-equilibrium activities such as growth, replication and self-propelled motility. An obvious example of active colloids is a suspension of bacteria such as Escherichia coli, their physical dimensions being almost invariably in the colloidal range. Synthetic self-propelled particles have also become available recently, such as two-faced, or Janus, particles propelled by differential chemical reactions on their surfaces driving a self-phoretic motion. In these lectures, I give a pedagogical introduction to the physics of single-particle and collective properties of active colloids, focussing on self propulsion. I will compare and contrast phenomena in suspensions of `swimmers' with the behaviour of suspensions of passive particles, where only Brownian motion (discovered by Robert Brown in granules from the pollen of the wild flower {\\it Clarkia pulchella}) is relevant. I will pay particular attention to issues that pertain to performing experiments using these active particle suspensions, such as how to characterise the suspension's swimming speed distribution, and include an appendix to guide physicists wanting to start culturing motile bacteria.

W C K Poon

2013-06-20T23:59:59.000Z

292

A multi-scale approach to molecular dynamics simulations of shock waves  

DOE Green Energy (OSTI)

Study of the propagation of shock waves in condensed matter has led to new discoveries ranging from new metastable states of carbon [1] to the metallic conductivity of hydrogen in Jupiter, [2] but progress in understanding the microscopic details of shocked materials has been extremely difficult. Complications can include the unexpected formation of metastable states of matter that determine the structure, instabilities, and time-evolution of the shock wave. [1,3] The formation of these metastable states can depend on the time-dependent thermodynamic pathway that the material follows behind the shock front. Furthermore, the states of matter observed in the shock wave can depend on the timescale on which observation is made. [4,1] Significant progress in understanding these microscopic details has been made through molecular dynamics simulations using the popular non-equilibrium molecular dynamics (NEMD) approach to atomistic simulation of shock compression. [5] The NEMD method involves creating a shock at one edge of a large system by assigning some atoms at the edge a fixed velocity. The shock propagates across the computational cell to the opposite side. The computational work required by NEMD scales at least quadratically in the evolution time because larger systems are needed for longer simulations to prevent the shock wave from reflecting from the edge of the computational cell and propagating back into the cell. When quantum mechanical methods with poor scaling of computational effort with system size are employed, this approach to shock simulations rapidly becomes impossible.

Reed, E J; Fried, L E; Manaa, M R; Joannopoulos, J D

2004-09-03T23:59:59.000Z

293

Cold Fronts in CDM clusters  

E-Print Network (OSTI)

Recently, high-resolution Chandra observations revealed the existence of very sharp features in the X-ray surface brightness and temperature maps of several clusters (Vikhlinin et. al., 2001). These features, called ``cold fronts'', are characterized by an increase in surface brightness by a factor >2 over 10-50 kpc, accompanied by a drop in temperature of a similar magnitude. The existence of such sharp gradients can be used to put interesting constraints on the physics of the intracluster medium (ICM), if their mechanism and longevity are well understood. Here, we present results of a search for cold fronts in high-resolution simulations of galaxy clusters in cold dark matter (CDM) models. We show that sharp gradients with properties similar to those of observed cold fronts naturally arise in cluster mergers when the shocks heat gas surrounding the merging sub-cluster, while its dense core remains relatively cold. The compression induced by supersonic motions and shock heating during the merger enhance the amplitude of gas density and temperature gradients across the front. Our results indicate that cold fronts are non-equilibrium transient phenomena and can be observed for a period of less than a billion years. We show that the velocity and density fields of gas surrounding the cold front can be very irregular which would complicate analyses aiming to put constraints on the physical conditions of the intracluster medium in the vicinity of the front.

Daisuke Nagai; Andrey V. Kravtsov

2002-06-26T23:59:59.000Z

294

Heat conductance in nonlinear lattices at small temperature gradients  

E-Print Network (OSTI)

This paper proposes a new methodological framework within which the heat conductance in 1D lattices can be studied. The total process of heat conductance is separated into two parts where the first one is the equilibrium process at equal temperatures $T$ of both ends and the second one -- non-equilibrium with the temperature $\\Delta T$ of one end and zero temperature of the other. This approach allows significant decrease of computational time at $\\Delta T \\to 0$. The threshold temperature $T_{\\rm thr}$ is found which scales $T_{\\rm thr}(N) \\sim N^{-3}$ with the lattice size $N$ and by convention separates two mechanisms of heat conductance: phonon mechanism dominates at $T T_{\\rm thr}$. Solitons and breathers are directly visualized in numerical experiments. The problem of heat conductance in non-linear lattices in the limit $\\Delta T \\to 0$ can be reduced to the heat conductance of harmonic lattice with time-dependent stochastic rigidities determined by the equilibrium process at temperature $T$. The detailed analysis is done for the $\\beta$-FPU lattice though main results are valid for one-dimensional lattices with arbitrary potentials.

T. Yu. Astakhova; V. N. Likhachev; G. A. Vinogradov

2010-06-09T23:59:59.000Z

295

Heat conductivity in the beta-FPU lattice. Solitons and breathers as energy carriers  

E-Print Network (OSTI)

This paper consists of two parts. The first part proposes a new methodological framework within which the heat conductivity in 1D lattices can be studied. The total process of heat conductivity is decomposed into two contributions where the first one is the equilibrium process at equal temperatures T of both lattice ends and the second -- non-equilibrium process with the temperature \\Delta T of one end and zero temperature of the other. The heat conductivity in the limit \\Delta T \\to 0 is reduced to the heat conductivity of harmonic lattice. A threshold temperature T_{thr} scales T_{thr}(N) \\sim N^{-3} with the lattice size N. Some unusual properties of heat conductivity can be exhibited on nanoscales at low temperatures. The thermodynamics of the \\beta-FPU lattice can be adequately approximated by the harmonic lattice. The second part testifies in the favor of the soliton and breather contribution to the heat conductivity in contrast to [N. Li, B. Li, S. Flach, PRL 105 (2010) 054102]. In the continuum limit the \\beta-FPU lattice is reduced to the modified Korteweg - de Vries equation with soliton and breather solutions. Numerical simulations demonstrate their high stability. New method for the visualization of moving solitons and breathers is suggested. An accurate expression for the dependence of the sound velocity on temperature is also obtained. Our results support the conjecture on the solitons and breathers contribution to the heat conductivity.

T. Yu. Astakhova; V. N. Likhachev; G. A. Vinogradov

2011-03-18T23:59:59.000Z

296

Conceptual Steps towards Exploring the Fundamental Nature of our Sun  

E-Print Network (OSTI)

One of the basic questions of solar research is the nature of the Sun. We show here how the plasma nature of the Sun leads to the self-generation of solar activity. The release of magnetic, rotational, gravitational, nuclear energies and that of the gravity mode oscillations deviate from uniformity and spherical symmetry. Through instabilities they lead to the emergence of sporadic and localized regions like flux tubes, electric filaments, magnetic elements and high temperature regions. A systematic approach exploring the solar collective degrees of freedom, extending to ordering phenomena of the magnetic features related to Higgs fields, is presented. Handling solar activity as transformations of energies from one form to another one presents a picture on the network of the energy levels of the Sun, showing that the Sun is neither a mere "ball of gas" nor a "quiescent steady-state fusion-reactor machine", but a complex self-organizing system. Since complex self-organizing systems are similar to living systems (and, by some opinion, identical with them), we also consider what arguments indicate the living nature of the Sun. Thermodynamic characteristics of the inequilibrium Sun are found important in this respect and numerical estimations of free energy rate densities and specific exergies are derived. KEY WORDS solar physics, degrees of freedom, self-organizing complex systems, non-equilibrium thermodynamics, astrobiology CLASSIFICATION PACS: 01.70.+w, 96.60.Rd

A. Grandpierre

2004-07-19T23:59:59.000Z

297

Thermodynamics of quantum jump trajectories in systems driven by classical fluctuations  

E-Print Network (OSTI)

The large-deviation method can be used to study the measurement trajectories of open quantum systems. For optical arrangements this formalism allows to describe the long time properties of the (non-equilibrium) photon counting statistics in the context of a (equilibrium) thermodynamic approach defined in terms of dynamical phases and transitions between them in the trajectory space [J.P. Garrahan and I. Lesanovsky, Phys. Rev. Lett. 104, 160601 (2010)]. In this paper, we study the thermodynamic approach for fluorescent systems coupled to complex reservoirs that induce stochastic fluctuations in their dynamical parameters. In a fast modulation limit the thermodynamics corresponds to that of a Markovian two-level system. In a slow modulation limit, the thermodynamic properties are equivalent to those of a finite system that in an infinite-size limit is characterized by a first-order transition. The dynamical phases correspond to different intensity regimes, while the size of the system is measured by the transition rate of the bath fluctuations. As a function of a dimensionless intensive variable, the first and second derivative of the thermodynamic potential develop an abrupt change and a narrow peak respectively. Their scaling properties are consistent with a double-Gaussian probability distribution of the associated extensive variable.

Adrian A. Budini

2010-12-03T23:59:59.000Z

298

A High Temperature Liquid Plasma Model of the Sun  

E-Print Network (OSTI)

In this work, a liquid model of the Sun is presented wherein the entire solar mass is viewed as a high density/high energy plasma. This model challenges our current understanding of the densities associated with the internal layers of the Sun, advocating a relatively constant density, almost independent of radial position. The incompressible nature of liquids is advanced to prevent solar collapse from gravitational forces. The liquid plasma model of the Sun is a non-equilibrium approach, where nuclear reactions are free to occur throughout the solar mass. The primary means of addressing internal heat transfer are convection and conduction. As a result of the convective processes on the solar surface, the liquid model brings into question the established temperature of the solar photosphere by highlighting a violation of Kirchhoff's law of thermal emission. Along these lines, the model emphasizes that radiative emission is a surface phenomenon. Strong evidence is provided that the Sun is a high density/high energy liquid plasma. This evidence is based on our knowledge of Planckian thermal emission and condensed matter, including the existence of pressure ionization and liquid metallic hydrogen at high temperatures and pressures. The equations of magnetohydrodynamics are invoked as the proper vehicle for the understanding od stellar convection and structure. Prior to introducing the liquid plasma model, the historic and scientific justifications for the gaseous model of the Sun are reviewed and the gaseous equations of state are also discussed.

Pierre-Marie Robitaille

2004-10-04T23:59:59.000Z

299

J. Math. Biol. DOI 10.1007/s00285-006-0043-9 Mathematical Biology Mathematical and theoretical biology for systems biology, and then...vice versa  

E-Print Network (OSTI)

Systems Biology has two roots (1). The better known resides in Molecular Biology, grew to functional genomics and then became top-down, genomewide Systems Biology. The less-publicized root resides in theoretical and Mathematical Biology, with topics such as non-equilibrium thermodynamics, self-organization, kinetic modelling, metabolic control analysis, flux analysis and biochemical systems theory, culminating in genome-wide versions thereof. It is anticipated that from these roots a Biology of unprecedented strength and quality will emerge, which ends the deadlocks of functional genomics drowning in its oceans of data and of Mathematical Biology escaping reality. Much of the growth in Systems Biology has bypassed Mathematical and Theoretical Biology. Only at the 2005 ESMTB meeting in Dresden did the surge in Systems Biology activity seen in molecular cell biology, begin to be mirrored by a similar surge in Mathematical Biology. Until then, the more theoretical activities in Systems Biology involved engineers much more than mathematicians. Why has this been the case? Systems Biology is well-defined and broad at the same time, not unlike Mathematical Biology. It is the science that studies how functional biological properties arise in the interactions of components (2,

Hans V. Westerhoff; H. V. Westerhoff (b

2006-01-01T23:59:59.000Z

300

Thermodynamic and transport properties of two-temperature SF{sub 6} plasmas  

Science Conference Proceedings (OSTI)

This paper deals with thermodynamic and transport properties of SF{sub 6} plasmas in a two-temperature model for both thermal equilibrium and non-equilibrium conditions. The species composition and thermodynamic properties are numerically determined using the two-temperature Saha equation and Guldberg-Waage equation according to deviation of van de Sanden et al. Transport properties including diffusion coefficient, viscosity, thermal conductivity, and electrical conductivity are calculated with most recent collision interaction potentials by adopting Devoto's electron and heavy particle decoupling approach but expanded to the third-order approximation (second-order for viscosity) in the frame of Chapman-Enskog method. The results are computed for various values of pressures from 0.1 atm to 10 atm and ratios of the electron temperature to the heavy particle temperature from 1 to 20 with electron temperature range from 300 to 40 000 K. In the local thermodynamic equilibrium regime, results are compared with available results of previously published studies.

Wang Weizong [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom); Rong Mingzhe; Wu Yi [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 (China); Spencer, Joseph W.; Yan, Joseph D.; Mei, DanHua [Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ (United Kingdom)

2012-08-15T23:59:59.000Z

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301

Improving reservoir conformance using gelled polymer systems. Annual report, September 15, 1993--September 24, 1994  

SciTech Connect

The objectives of the research program are to (1) identify and develop polymer systems which have potential to improve reservoir conformance of fluid displacement processes, (2) determine the performance of these systems in bulk and in porous media, and (3) develop methods to predict their performance in field applications. The research focuses on three types of aqueous gel systems - a polysaccharide (KUSP1) that gels as a function of pH, a polyacrylamide-chromium(III) system and a polyacrylamide-aluminum citrate system. This report describes work conducted during the second year of a three-year program. Progress was made in the utilization of KUSP1 as a gelling agent. It was shown that gels can be formed in situ in porous media using CO{sub 2} or ester hydrolysis to lower pH. An ester was identified that could be used in field-scale operations. It was determined that KUSP1 will form strong gels when ortho boric acid is added to the system. It was also determined, in cooperation with Abbott Laboratories, that KUSP1 can be produced on a commercial scale. Rheological studies showed that shear rate significantly affects gelation time and gel strength. The effect of rock-fluid interactions at alkaline conditions was examined experimentally and through mathematical modeling. A model was developed that treats non-equilibrium conditions and this is an improvement over previously published models.

Green, D.W.; Willhite, G.P.

1995-07-01T23:59:59.000Z

302

Phase behaviour of active Brownian particles: The role of dimensionality  

E-Print Network (OSTI)

Recently, there has been much interest in activity-induced phase separations in concentrated suspensions of "active Brownian particles" (ABPs), self-propelled spherical particles whose direction of motion relaxes through thermal rotational diffusion. To date, almost all these studies have been restricted to 2 dimensions. In this work, therefore, we study activity-induced phase separation in 3D and compare the results with previous and new 2D simulations. To this end, we performed state-of-the-art Brownian dynamics simulations of up to 40 million ABPs - such very large system sizes are unavoidable to evade finite size effects in 3D. Our results confirm the picture established for 2D systems in which an activity-induced phase separation occurs, with strong analogies to equilibrium gas-liquid spinodal decomposition, in spite of the purely non-equilibrium nature of the driving force behind the phase separation. However, we also find important differences between the 2D and 3D cases. Firstly, the shape and position of the phase boundaries is markedly different for the two cases. Secondly, for the 3D coarsening kinetics we find that the domain size grows in time according to the classical diffusive $t^{1/3}$ law, in contrast to the nonstandard subdiffusive exponent observed in 2D.

Joakim Stenhammar; Davide Marenduzzo; Rosalind J. Allen; Michael E. Cates

2013-10-23T23:59:59.000Z

303

Analytical Boltzmann moments for electrons in N{sub 2}-O{sub 2}-H{sub 2}O gas mixtures  

DOE Green Energy (OSTI)

Non-equilibrium gas plasmas are under study today as sources of electrically powered chemistry for the elimination of volatile organic vapors and combustion exhaust pollutants. The aim of these research efforts is to develop either non-catalytic oxidation to acids which can be ``scrubbed`` out of gas flows as salts, or non-catalytic reduction, specifically of NO{sub x} to N{sub 2} and O{sub 2}. This work is an effort to simplify the electron kinetics so as to enable a convenient study of a wide range of mixtures and Townsend parameters, and for a reasonable sacrifice in precision. Key insights gained in this way can be honed by more accurate numerical computation as needed. In this report they present a brief description of the approximate analytical solution of the Boltzmann equation, then additional modeling of electron-molecule cross sections which simplifies the expressions for moments, and finally a number of examples and comparisons to experiment and published results.

Garcia, M.; Chang, B.

1994-04-01T23:59:59.000Z

304

Optimization of reactive distillation processes with simulated annealing  

E-Print Network (OSTI)

A simulated annealing-based algorithm (MSIMPSA) suitable for the optimization of mixed integer non-linear programming (MINLP) problems was applied to the synthesis of a non-equilibrium reactive distillation column. A simulation model based on an extension of conventional distillation is proposed for the simulation step of the optimization problem. In the case of ideal vapor}liquid equilibrium, the simulation results are similar to those obtained by Ciric and Gu (1994, AIChE Journal, 40(9), 1479) using the GAMS environment and to those obtained with the AspenPlus modular simulator. The optimization results are also similar to those previously reported and similar to those using an adaptive random search algorithm (MSGA). The optimizations were also performed with non-ideal vapor}liquid equilibrium, considering either distributed feed and reaction trays or single feed and reaction tray. The results show that the optimized objective function values are very similar, and mostly independent of the number of trays and of the reaction distribution. It is shown that the proposed simulation/optimization equation-oriented environments are capable of providing optimized solutions which are close to the global optimum, and reveal its adequacy for the optimization of reactive distillation

M. F. Cardoso; R. L. Salcedo; S. Feyo De Azevedo; D. Barbosa

1999-01-01T23:59:59.000Z

305

RAMONA-4B a computer code with three-dimensional neutron kinetics for BWR and SBWR system transient - models and correlations  

Science Conference Proceedings (OSTI)

This document describes the major modifications and improvements made to the modeling of the RAMONA-3B/MOD0 code since 1981, when the code description and assessment report was completed. The new version of the code is RAMONA-4B. RAMONA-4B is a systems transient code for application to different versions of Boiling Water Reactors (BWR) such as the current BWR, the Advanced Boiling Water Reactor (ABWR), and the Simplified Boiling Water Reactor (SBWR). This code uses a three-dimensional neutron kinetics model coupled with a multichannel, non-equilibrium, drift-flux, two-phase flow formulation of the thermal hydraulics of the reactor vessel. The code is designed to analyze a wide spectrum of BWR core and system transients and instability issues. Chapter 1 is an overview of the code`s capabilities and limitations; Chapter 2 discusses the neutron kinetics modeling and the implementation of reactivity edits. Chapter 3 is an overview of the heat conduction calculations. Chapter 4 presents modifications to the thermal-hydraulics model of the vessel, recirculation loop, steam separators, boron transport, and SBWR specific components. Chapter 5 describes modeling of the plant control and safety systems. Chapter 6 presents and modeling of Balance of Plant (BOP). Chapter 7 describes the mechanistic containment model in the code. The content of this report is complementary to the RAMONA-3B code description and assessment document. 53 refs., 81 figs., 13 tabs.

Rohatgi, U.S.; Cheng, H.S.; Khan, H.J.; Mallen, A.N.; Neymotin, L.Y.

1998-03-01T23:59:59.000Z

306

Horizontal Steam Generator Thermal-Hydraulics at Various Steady-State Power Levels  

Science Conference Proceedings (OSTI)

Three-dimensional computer simulation and analyses of the horizontal steam generator thermal-hydraulics of the WWER 1000 nuclear power plant have been performed for 50% and 75% partial loads, 100% nominal load and 110% over-load. Presented results show water and steam mass flow rate vectors, steam void fraction spatial distribution, recirculation zones, swell level position, water mass inventory on the shell side, and other important thermal-hydraulic parameters. The simulations have been performed with the computer code 3D ANA, based on the 'two-fluid' model approach. Steam-water interface transport processes, as well as tube bundle flow resistance, energy transfer, and steam generation within tube bundles are modelled with {sup c}losure laws{sup .} Applied approach implies non-equilibrium thermal and flow conditions. The model is solved by the control volume procedure, which has been extended in order to take into account the 3D flow of liquid and gas phase. The methodology is validated by comparing numerical and experimental results of real steam generator operational conditions at various power levels of the WWER Novovoronezh, Unit 5. One-dimensional model of the horizontal steam generator has been built with the RELAP 5 standard code on the basis of the multidimensional two-phase flow structure obtained with the 3D ANA code. RELAP 5 and 3D ANA code results are compared, showing acceptable agreement. (authors)

Stevanovic, Vladimir D. [University of Belgrade, Kraljice Marije 16, 11000 Belgrade, Serbia and Montenegro (Yugoslavia); Stosic, Zoran V.; Kiera, Michael; Stoll, Uwe [Framatome ANP GmbH, P.O. Box 3220, 91050 Erlangen (Germany)

2002-07-01T23:59:59.000Z

307

Plasma and Ion Assistance in Physical Vapor Deposition: AHistorical Perspective  

SciTech Connect

Deposition of films using plasma or plasma-assist can betraced back surprisingly far, namely to the 18th century for arcs and tothe 19th century for sputtering. However, only since the 1960s thecoatings community considered other processes than evaporation for largescale commercial use. Ion Plating was perhaps the first importantprocess, introducing vapor ionization and substrate bias to generate abeam of ions arriving on the surface of the growing film. Ratherindependently, cathodic arc deposition was established as an energeticcondensation process, first in the former Soviet Union in the 1970s, andin the 1980s in the Western Hemisphere. About a dozen various ion-basedcoating technologies evolved in the last decades, all characterized byspecific plasma or ion generation processes. Gridded and gridless ionsources were taken from space propulsion and applied to thin filmdeposition. Modeling and simulation have helped to make plasma and ionseffects to be reasonably well understood. Yet--due to the complex, oftennon-linear and non-equilibrium nature of plasma and surfaceinteractions--there is still a place for the experience plasma"sourcerer."

Anders, Andre

2007-02-28T23:59:59.000Z

308

Tritium generation and neutron measurements in Pd-Si under high deuterium gas pressure  

SciTech Connect

This paper summarizes some of the methods applicable for low level tritium detection needed in the search for anomalous fusion in metal hydrides. It is also intended to further detail our tritium and neutron results that have been obtained with the Pd-Si-D system, originally presented at earlier workshops. A measure of reproducibility that was not evident in our previous work has been achieved partially due to the better detection sensitivity afforded by the use of low tritium deuterium and partially from the fact that the foil-wafer cells can be made with nearly identical electrical characteristics. This reproducibility has allowed us to narrow the optimum conditions for the experiment. While this experiment is rather different from the standard'' electrolytic cell or the Ti gas hydride experiment, similarities exist in that non equilibrium conditions are sought and the tritium generation levels are low and neutron emission is extremely weak. In contrast to many electrochemical cell experiments, the system used in these experiments is completely sealed during operation and uses no electrolyte. The major improvements to the experiment have been the use of vary low tritium deuterium for the hydriding and the replacement of the aluminum neutron counter tubes with ones of stainless steel. These changes have resulted in pronounced improvements to the detection systems since the background tritium level in the gas has been reduced by a factor of 300 and the neutron background has been decreased by a factor of 14. 16 refs., 8 figs., 1 tab.

Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.

1991-01-01T23:59:59.000Z

309

Modeling the reactive inorganic solute distributions in the groundwater flow systems of the Hanford Site using inverse analytical modeling techniques  

E-Print Network (OSTI)

Inverse analytical techniques were used to model solute distributions and determine transport parameters for two flow systems in the Yakima Basalt subgroup at the Hanford Site in Washington state. Previous studies of these flow systems used chloride as a tracer to determine the transverse dispersivities of several of the Hanford flow systems. This study analyzes three reactive solute distributions, two of which are coincident, to determine aquifer and solute reactions parameters. In addition to modeling the transport of two solutes, a chemical speciation model, MINTEQA2, was used to determine saturation indices for the sample waters in an effort to verify observed secondary mineralization. Boron and potassium were the two solute distributions modeled in this study. The analytical model results accurately reproduce the observed field conditions, comply with the assumptions of the conceptual model, and match the results of the previous chloride study. The parameters determined by the analytical model include the source size and dimension, transverse dispersivity, and reaction rate/solute velocity ratio. The reaction rate term is used to describe the first order reactions experienced by boron and potassium. This term is believed to represent the affect of both precipitation and non-equilibrium sorption reactions. Due to the nature of the problem, this ratio cannot be separated for its individual terms. However, the relative rates of reaction for the solutes are determined.

Adamski, Mark Robert

1993-01-01T23:59:59.000Z

310

CAirTOX: A compartment model for assessing the fate of and human exposure to toxic-chemical emissions to air  

Science Conference Proceedings (OSTI)

CAirTOX has been developed as a spreadsheet model to assist in making a risk assessment of toxic air emissions. With CAirTOX, one can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The multimedia transport and transformation model is a steady-state, but non-equilibrium model that can be used to assess concentrations of contaminants released continuously to air. In Part 1, the authors describe the multimedia transport and transformation model used to determine the fate of air emissions. In Part 2, they describe inputs and data needs for CAirTOX and the development of a set of landscape factors, which can be used to represent regional air basin/water-shed systems in California. In Part 3, they describe the multiple-pathway exposure scenarios and exposure algorithms. In Part 4, they compare the HRA approach and results and the CAirTOX exposure equations. In Part 5, they consider model sensitivity and uncertainty to determine how variability and uncertainty in model inputs affects the precision, accuracy, and credibility of the model output.

McKone, T.E.

1993-10-01T23:59:59.000Z

311

Feedback control of flow alignment in sheared liquid crystals  

E-Print Network (OSTI)

Based on a continuum theory, we investigate the manipulation of the non-equilibrium behavior of a sheared liquid crystal via closed-loop feedback control. Our goal is to stabilize a specific dynamical state, that is, the stationary "flow-alignment", under conditions where the uncontrolled system displays oscillatory director dynamics with in-plane symmetry. To this end we employ time-delayed feedback control (TDFC), where the equation of motion for the ith component, q_i(t), of the order parameter tensor is supplemented by a control term involving the difference q_i(t)-q_i(t-\\tau). In this diagonal scheme, \\tau is the delay time. We demonstrate that the TDFC method successfully stabilizes flow alignment for suitable values of the control strength, K, and \\tau; these values are determined by solving an exact eigenvalue equation. Moreover, our results show that only small values of K are needed when the system is sheared from an isotropic equilibrium state, contrary to the case where the equilibrium state is nematic.

David A. Strehober; Eckehard Schll; Sabine H. L. Klapp

2013-08-29T23:59:59.000Z

312

Topological field theory of dynamical systems  

SciTech Connect

Here, it is shown that the path-integral representation of any stochastic or deterministic continuous-time dynamical model is a cohomological or Witten-type topological field theory, i.e., a model with global topological supersymmetry (Q-symmetry). As many other supersymmetries, Q-symmetry must be perturbatively stable due to what is generically known as non-renormalization theorems. As a result, all (equilibrium) dynamical models are divided into three major categories: Markovian models with unbroken Q-symmetry, chaotic models with Q-symmetry spontaneously broken on the mean-field level by, e.g., fractal invariant sets (e.g., strange attractors), and intermittent or self-organized critical (SOC) models with Q-symmetry dynamically broken by the condensation of instanton-antiinstanton configurations (earthquakes, avalanches, etc.) SOC is a full-dimensional phase separating chaos and Markovian dynamics. In the deterministic limit, however, antiinstantons disappear and SOC collapses into the 'edge of chaos.' Goldstone theorem stands behind spatio-temporal self-similarity of Q-broken phases known under such names as algebraic statistics of avalanches, 1/f noise, sensitivity to initial conditions, etc. Other fundamental differences of Q-broken phases is that they can be effectively viewed as quantum dynamics and that they must also have time-reversal symmetry spontaneously broken. Q-symmetry breaking in non-equilibrium situations (quenches, Barkhausen effect, etc.) is also briefly discussed.

Ovchinnikov, Igor V. [Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, California 90095-1594 (United States)

2012-09-15T23:59:59.000Z

313

A CR-hydro-NEI Model of Multi-wavelength Emission from the Vela Jr. Supernova Remnant (SNR RX J0852.0-4622)  

E-Print Network (OSTI)

Based largely on energy budget considerations and the observed cosmic-ray (CR) ionic composition, supernova remnant (SNR) blast waves are the most likely sources of CR ions with energies at least up to the "knee" near 3 PeV. Shocks in young shell-type TeV-bright SNRs are surely producing TeV particles, but the emission could be dominated by ions producing neutral pion-decay emission or electrons producing inverse-Compton gamma-rays. Unambiguously identifying the GeV-TeV emission process in a particular SNR will not only help pin down the origin of CRs, it will add significantly to our understanding of the diffusive shock acceleration (DSA) mechanism and improve our understanding of supernovae and the impact SNRs have on the circumstellar medium. In this study, we investigate the Vela Jr. SNR, an example of TeV-bright non-thermal SNRs. We perform hydrodynamic simulations coupled with non-linear DSA and non-equilibrium ionization near the forward shock (FS) to confront currently available multi-wavelength data....

Lee, Shiu-Hang; Ellison, Donald C; Nagataki, Shigehiro; Patnaude, Daniel J

2013-01-01T23:59:59.000Z

314

Emergence of Quantum Mechanics from a Sub-Quantum Statistical Mechanics  

E-Print Network (OSTI)

A research program within the scope of theories on "Emergent Quantum Mechanics" is presented, which has gained some momentum in recent years. Via the modeling of a quantum system as a non-equilibrium steady-state maintained by a permanent throughput of energy from the zero-point vacuum, the quantum is considered as an emergent system. We implement a specific "bouncer-walker" model in the context of an assumed sub-quantum statistical physics, in analogy to the results of experiments by Couder's group on a classical wave-particle duality. We can thus give an explanation of various quantum mechanical features and results on the basis of a "21st century classical physics", such as the appearance of Planck's constant, the Schr\\"odinger equation, etc. An essential result is given by the proof that averaged particle trajectories' behaviors correspond to a specific type of anomalous diffusion termed "ballistic" diffusion on a sub-quantum level. It is further demonstrated both analytically and with the aid of computer simulations that our model provides explanations for various quantum effects such as double-slit or n-slit interference. We show the averaged trajectories emerging from our model to be identical to Bohmian trajectories, albeit without the need to invoke complex wave functions or any other quantum mechanical tool. Finally, the model provides new insights into the origins of entanglement, and, in particular, into the phenomenon of a "systemic" nonlocality.

Gerhard Groessing

2013-04-12T23:59:59.000Z

315

Synchronization in Complex Oscillator Networks and Smart Grids  

SciTech Connect

The emergence of synchronization in a network of coupled oscillators is a fascinating topic in various scientific disciplines. A coupled oscillator network is characterized by a population of heterogeneous oscillators and a graph describing the interaction among them. It is known that a strongly coupled and sufficiently homogeneous network synchronizes, but the exact threshold from incoherence to synchrony is unknown. Here we present a novel, concise, and closed-form condition for synchronization of the fully nonlinear, non-equilibrium, and dynamic network. Our synchronization condition can be stated elegantly in terms of the network topology and parameters, or equivalently in terms of an intuitive, linear, and static auxiliary system. Our results significantly improve upon the existing conditions advocated thus far, they are provably exact for various interesting network topologies and parameters, they are statistically correct for almost all networks, and they can be applied equally to synchronization phenomena arising in physics and biology as well as in engineered oscillator networks such as electric power networks. We illustrate the validity, the accuracy, and the practical applicability of our results in complex networks scenarios and in smart grid applications.

Dorfler, Florian [Los Alamos National Laboratory; Chertkov, Michael [Los Alamos National Laboratory; Bullo, Francesco [Center for Control, Dynamical Systems and Computation, University of California at Santa Babara, Santa Barbara CA

2012-07-24T23:59:59.000Z

316

Synchronization in Complex Oscillator Networks and Smart Grids  

E-Print Network (OSTI)

The emergence of synchronization in a network of coupled oscillators is a fascinating topic in various scientific disciplines. A coupled oscillator network is characterized by a population of heterogeneous oscillators and a graph describing the interaction among them. It is known that a strongly coupled and sufficiently homogeneous network synchronizes, but the exact threshold from incoherence to synchrony is unknown. Here we present a novel, concise, and closed-form condition for synchronization of the fully nonlinear, non-equilibrium, and dynamic network. Our synchronization condition can be stated elegantly in terms of the network topology and parameters, or equivalently in terms of an intuitive, linear, and static auxiliary system. Our results significantly improve upon the existing conditions advocated thus far, they are provably exact for various interesting network topologies and parameters, they are statistically correct for almost all networks, and they can be applied equally to synchronization phenomena arising in physics and biology as well as in engineered oscillator networks such as electric power networks. We illustrate the validity, the accuracy, and the practical applicability of our results in complex networks scenarios and in smart grid applications.

Florian Drfler; Michael Chertkov; Francesco Bullo

2012-07-31T23:59:59.000Z

317

Probing Planck-scale physics with Extragalactic Sources?  

E-Print Network (OSTI)

At Planck-scale, spacetime is foamy due to quantum fluctuations predicted by quantum gravity. Here we consider the possibility of using spacetime foam-induced phase incoherence of light from distant galaxies and gamma-ray bursters to probe Planck-scale physics. In particular, we critically examine the cumulative effects of spacetime fluctuations over a huge distance. Unfortunately, our analysis shows that they are far below what is required in this approach to shed light on the foaminess of spacetime. Subject headings: Planck-scale physics, quantum foam-induced phase incoherence of light, gamma-ray bursts, distant galaxies It is generally believed that quantum gravity, the synthesis of quantum mechanics and general relativity, predicts that spacetime becomes foamy or fuzzy at the Planck scale given by the Planck time tP = (?G/c5) 1/2 ? 10?44s, Planck length lP = ctP ? 10?33cm, and Planck energy EP = ?/tP ? 1028eV. The fuzziness of spacetime leads to uncertainties in distance (l) measurements whose absolute value is given by ?l ? lP(l/lP) 1?? (similar uncertainties for time measurements) and uncertainties in energy (E) measurements given by ?E ? E(E/EP) ? (again ?E is an absolute value). Similar uncertainties for momentum measurements also obtain.(Ng & van Dam 1994) The parameter, ? ? 1, specifies different quantum gravity models. The standard choice(Misner et al 1973) of ? is ? = 1; the choice of ? = 2/3 appears(Ng & van Dam 2000; Ng 2001) to be consistent with the holographic principle(tHooft 1993; Susskind 1995) and black hole physics; ? = 1/2 corresponds to the random-walk model found in the literature(Amelino-Camelia

Y. Jack Ng; W. A. Christiansen; H. Van Dam

2003-01-01T23:59:59.000Z

318

Stochastic Dynamical Structure (SDS) of Nonequilibrium Processes in the Absence of Detailed Balance. II: construction of SDS with nonlinear force and multiplicative noise  

E-Print Network (OSTI)

There is a whole range of emergent phenomena in non-equilibrium behaviors can be well described by a set of stochastic differential equations. Inspired by an insight gained during our study of robustness and stability in phage lambda genetic switch in modern biology, we found that there exists a classification of generic nonequilibrium processes: In the continuous description in terms of stochastic differential equations, there exists four dynamical elements: the potential function $\\phi$, the friction matrix $ S$, the anti-symmetric matrix $ T $, and the noise. The generic feature of absence of detailed balance is then precisely represented by $T$. For dynamical near a fixed point, whether or not it is stable or not, the stochastic dynamics is linear. A rather complete analysis has been carried out (Kwon, Ao, Thouless, cond-mat/0506280; PNAS, {\\bf 102} (2005) 13029), referred to as SDS I. One important and persistent question is the existence of a potential function with nonlinear force and with multiplicative noise, with both nice local dynamical and global steady state properties. Here we demonstrate that a dynamical structure built into stochastic differential equation allows us to construct such a global optimization potential function. First, we provide the construction. One of most important ingredient is the generalized Einstein relation. We then present an approximation scheme: The gradient expansion which turns every order into linear matrix equations. The consistent of such methodology with other known stochastic treatments will be discussed in next paper, SDS III; and the explicitly connection to statistical mechanics and thermodynamics will be discussed in a forthcoming paper, SDS IV.

P. Ao

2008-03-31T23:59:59.000Z

319

Nanoscale chemical and mechanical characterization of thin films:sum frequency generation (SFG) vibrational spectroscopy at buriedinterfaces  

SciTech Connect

Sum frequency generation (SFG) surface vibrational spectroscopy was used to characterize interfaces pertinent to current surface engineering applications, such as thin film polymers and novel catalysts. An array of advanced surface science techniques like scanning probe microscopy (SPM), x-ray photoelectron spectroscopy (XPS), gas chromatography (GC) and electron microscopy were used to obtain experimental measurements complementary to SFG data elucidating polymer and catalyst surface composition, surface structure, and surface mechanical behavior. Experiments reported in this dissertation concentrate on three fundamental questions: (1) How does the interfacial molecular structure differ from that of the bulk in real world applications? (2) How do differences in chemical environment affect interface composition or conformation? (3) How do these changes correlate to properties such as mechanical or catalytic performance? The density, surface energy and bonding at a solid interface dramatically alter the polymer configuration, physics and mechanical properties such as surface glass transition, adhesion and hardness. The enhanced sensitivity of SFG at the buried interface is applied to three systems: a series of acrylates under compression, the compositions and segregation behavior of binary polymer polyolefin blends, and the changes in surface structure of a hydrogel as a function of hydration. In addition, a catalytically active thin film of polymer coated nanoparticles is investigated to evaluate the efficacy of SFG to provide in situ information for catalytic reactions involving small mass adsorption and/or product development. Through the use of SFG, in situ total internal reflection (TIR) was used to increase the sensitivity of SFG and provide the necessary specificity to investigate interfaces of thin polymer films and nanostructures previously considered unfeasible. The dynamic nature of thin film surfaces is examined and it is found that the non-equilibrium states contribute to practical applications of acrylates, blends and hydrogels. Lastly, nanoparticle surfaces and the catalytic activity and selectivity of platinum cube nanoparticles are correlated to the surface intermediates in a high pressure flow reactor.

Kweskin, S.J.

2006-05-19T23:59:59.000Z

320

Studies of complex fragment emission in heavy ion reactions. Progress report, January 1, 1990--August 5, 1992  

Science Conference Proceedings (OSTI)

Our work involves the study of intermediate energy heavy-ion nuclear reactions. This work has two foci. On the one hand, we desire to learn about the properties of nuclear matter under abnormal conditions, in this energy domain, predominately low densities. This purpose runs abreast of the second, which is the study of the relevant reaction mechanisms. The two objectives are inexorably linked because our experimental laboratory for studying nuclear matter properties is a dynamic one. We are forced to ask how nuclear matter properties, such as phase transitions, are reflected in the dynamics of the reactions. It may be that irrefutable information about nuclear matter will not be extracted from the reaction work. Nevertheless, we are compelled to undertake this effort not only because it is the only game in town and as yet we do not know that information cannot be extracted, but also because of our second objective. The process leads to an understanding of the reaction mechanism themselves and therefore to the response characteristics of finite, perhaps non-equilibrium, strongly interacting systems. Our program has been: To study energy, mass, and angular momentum deposition by studying incomplete fusion reactions. To gain confidence that we understand how highly excited systems decompose by studying all emissions from the highly excited systems. To push these kinds of studies into the intermediate energy domain, with excitation function studies. And attempt to learn about the dynamics of the decays using particle-particle correlations. In the last effort, we have decided to focus on simple systems, where we believe, definitive statements are possible. These avenues of research share a common theme, large complex fragment production.

Charity, R.J.; Sobotka, L.G.

1992-09-01T23:59:59.000Z

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321

Studies of complex fragment emission in heavy ion reactions  

Science Conference Proceedings (OSTI)

Our work involves the study of intermediate energy heavy-ion nuclear reactions. This work has two foci. On the one hand, we desire to learn about the properties of nuclear matter under abnormal conditions, in this energy domain, predominately low densities. This purpose runs abreast of the second, which is the study of the relevant reaction mechanisms. The two objectives are inexorably linked because our experimental laboratory for studying nuclear matter properties is a dynamic one. We are forced to ask how nuclear matter properties, such as phase transitions, are reflected in the dynamics of the reactions. It may be that irrefutable information about nuclear matter will not be extracted from the reaction work. Nevertheless, we are compelled to undertake this effort not only because it is the only game in town and as yet we do not know that information cannot be extracted, but also because of our second objective. The process leads to an understanding of the reaction mechanism themselves and therefore to the response characteristics of finite, perhaps non-equilibrium, strongly interacting systems. Our program has been: To study energy, mass, and angular momentum deposition by studying incomplete fusion reactions. To gain confidence that we understand how highly excited systems decompose by studying all emissions from the highly excited systems. To push these kinds of studies into the intermediate energy domain, with excitation function studies. And attempt to learn about the dynamics of the decays using particle-particle correlations. In the last effort, we have decided to focus on simple systems, where we believe, definitive statements are possible. These avenues of research share a common theme, large complex fragment production.

Charity, R.J.; Sobotka, L.G.

1992-01-01T23:59:59.000Z

322

Microscopic quantum structure of black hole and vacuum versus quantum statistical origin of gravity  

E-Print Network (OSTI)

The Planckon densely piled model of vacuum is proposed. Based on it, the microscopic quantum structure of Schwarzschild black hole and quantum statistical origin of its gravity are studied. It is shown that thermodynamic temperature equilibrium and mechanical acceleration balance make the space-time of the black hole horizon singular and Casimir effect works inside the horizon. This effect makes the inside vacuum have less zero fluctuation energy than the outside vacuum, and a temperature difference as well as gravity as thermal pressure are created. A dual relation between inside and outside regions of the black hole is found. By the dual relation, an attractor behaviour of the horizon surface is unveiled. Outside horizon, there exist thermodynamic non-equilibrium and mechanical non-balance which lead to outward centrifugal energy flow and inward gravitation energy flow, their compensation establishes local equilibrium. The lost vacuum energy in negative gravitation potential regions has been removed to the black hole surface to form a spherical Planckon shell with the thickness of Planckon diameter. All the particles absorbed by the black hole have fallen down to the horizon and converted into spin 1/2 radiation quanta made of standing waves on the horizon sphere with the mean energy related to Hawking-Unruh temperature, thermodynamic equilibrium and mechanical balance keep them stable and be tightly bound in the horizon. The gravitation mass 2M and physical mass $M$ of the black hole are calculated. The entropy of the black hole, calculated from the microscopic state number of the many-body system of radiation fermion quanta, is well consistent with Hawking. A radical modification of the temperature law of the black hole is made. The accelerating expansion of the universe yields the expansion cosmon and its energy density agrees with dark energy density.

Shun-Jin Wang

2012-12-24T23:59:59.000Z

323

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. The in situ electrical conductivity and Seebeck coefficient measurements were made on LSFT at 1000 and 1200 C over the oxygen activity range from air to 10{sup -15} atm. The electrical conductivity measurements exhibited a p to n type transition at an oxygen activity of 1 x 10{sup -10} at 1000 C and 1 x 10{sup -6} at 1200 C. Thermogravimetric studies were also carried out over the same oxygen activities and temperatures. Based on the results of these measurements, the chemical and mechanical stability range of LSFT were determined and defect structure was established. The studies on the fracture toughness of the LSFT and dual phase membranes exposed to air and N{sub 2} at 1000 C was done and the XRD and SEM analysis of the specimens were carried out to understand the structural and microstructural changes. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affect the mechanical properties. A complete transformation of fracture behavior was observed in the N{sub 2} treated LSFT samples. Further results to investigate the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Recent results on transient kinetic data are presented. The 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model is used to study ''frozen'' profiles in patterned or composite membranes.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-02-01T23:59:59.000Z

324

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the previous research, the reference point of oxygen occupancy was determined and verified. In the current research, the oxygen occupancy was investigated at 1200 C as a function of oxygen activity and compared with that at 1000 C. The cause of bumps at about 200 C was also investigated by using different heating and cooling rates during TGA. The fracture toughness of LSFT and dual phase membranes at room temperature is an important mechanical property. Vicker's indentation method was used to evaluate this toughness. Through this technique, a K{sub Ic} (Mode-I Fracture Toughness) value is attained by means of semi-empirical correlations between the indentation load and the length of the cracks emanating from the corresponding Vickers indentation impression. In the present investigation, crack propagation behavior was extensively analyzed in order to understand the strengthening mechanisms involved in the non-transforming La based ceramic composites. Cracks were generated using Vicker's indenter and used to identify and evaluate the toughening mechanisms involved. Preliminary results of an electron microscopy study of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Modeling of the isotopic transients on operating membranes (LSCrF-2828 at 900 C) and a ''frozen'' isotope profile have been analyzed in conjunction with a 1-D model to reveal the gradient in oxygen diffusivity through the membrane under conditions of high chemical gradients.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-08-01T23:59:59.000Z

325

Can the matter-antimatter asymmetry be easier to understand within the "spin-charge-family-theory", predicting twice four families and two times $SU(2)$ vector gauge and scalar fields?  

E-Print Network (OSTI)

This contribution is an attempt to try to understand the matter-antimatter asymmetry in the universe within the {\\it spin-charge-family-theory} if assuming that transitions in non equilibrium processes among instanton vacua and complex phases in mixing matrices are the sources of the matter-antimatter asymmetry, as studied in the literature for several proposed theories. The {\\it spin-charge-family-theory} is, namely, very promising in showing the right way beyond the {\\it standard model}. It predicts families and their mass matrices, explaining the origin of the charges and of the gauge fields. It predicts that there are, after the universe passes through two $SU(2)\\times U(1)$ phase transitions, in which the symmetry breaks from $SO(1,3) \\times SU(2) \\times SU(2) \\times U(1) \\times SU(3)$ first to $SO(1,3) \\times SU(2) \\times U(1) \\times SU(3)$ and then to $SO(1,3) \\times U(1) \\times SU(3)$, twice decoupled four families. The upper four families gain masses in the first phase transition, while the second four families gain masses at the electroweak break. To these two breaks of symmetries the scalar non Abelian fields, the (superposition of the) gauge fields of the operators generating families, contribute. The lightest of the upper four families is stable (in comparison with the life of the universe) and is therefore a candidate for constituting the dark matter. The heaviest of the lower four families should be seen at the LHC or at somewhat higher energies.

N. S. Mankoc Borstnik

2010-11-26T23:59:59.000Z

326

Lattice Boltzmann model for combustion and detonation  

E-Print Network (OSTI)

In this paper we present a lattice Boltzmann model for combustion and detonation. In this model the fluid behavior is described by a finite-difference lattice Boltzmann model by Gan et al. [Physica A, 2008, 387: 1721]. The chemical reaction is described by the Lee-Tarver model [Phys. Fluids, 1980, 23: 2362]. The reaction heat is naturally coupled with the flow behavior. Due to the separation of time scales in the chemical and thermodynamic processes, a key technique for a successful simulation is to use the operator-splitting scheme. The new model is verified and validated by well-known benchmark tests. As a specific application of the new model, we studied the simple steady detonation phenomenon. To show the merit of LB model over the traditional ones, we focus on the reaction zone to study the non-equilibrium effects. It is interesting to find that, at the von Neumann peak, the system is nearly in its thermodynamic equilibrium. At the two sides of the von Neumann peak, the system deviates from its equilibrium in opposite directions. In the front of von Neumann peak, due to the strong compression from the reaction product behind the von Neumann peak, the system experiences a sudden deviation from thermodynamic equilibrium. Behind the von Neumann peak, the release of chemical energy results in thermal expansion of the matter within the reaction zone, which drives the system to deviate the thermodynamic equilibrium in the opposite direction. From the deviation from thermodynamic equilibrium, defined in this paper, one can understand more on the macroscopic effects of the system due to the deviation from its thermodynamic equilibrium.

Bo Yan; Aiguo Xu; Guangcai Zhang; Yangjun Ying; Hua Li

2013-04-28T23:59:59.000Z

327

MASSES, RADII, AND CLOUD PROPERTIES OF THE HR 8799 PLANETS  

Science Conference Proceedings (OSTI)

The near-infrared colors of the planets directly imaged around the A star HR 8799 are much redder than most field brown dwarfs of the same effective temperature. Previous theoretical studies of these objects have concluded that the atmospheres of planets b, c, and d are unusually cloudy or have unusual cloud properties. Some studies have also found that the inferred radii of some or all of the planets disagree with expectations of standard giant planet evolution models. Here, we compare the available data to the predictions of our own set of atmospheric and evolution models that have been extensively tested against observations of field L and T dwarfs, including the reddest L dwarfs. Unlike some previous studies, we require mutually consistent choices for effective temperature, gravity, cloud properties, and planetary radius. This procedure thus yields plausible values for the masses, effective temperatures, and cloud properties of all three planets. We find that the cloud properties of the HR 8799 planets are not unusual but rather follow previously recognized trends, including a gravity dependence on the temperature of the L to T spectral transition-some reasons for which we discuss. We find that the inferred mass of planet b is highly sensitive to whether or not we include the H- and the K-band spectrum in our analysis. Solutions for planets c and d are consistent with the generally accepted constraints on the age of the primary star and orbital dynamics. We also confirm that, like in L and T dwarfs and solar system giant planets, non-equilibrium chemistry driven by atmospheric mixing is also important for these objects. Given the preponderance of data suggesting that the L to T spectral type transition is gravity dependent, we present an exploratory evolution calculation that accounts for this effect. Finally we recompute the bolometric luminosity of all three planets.

Marley, Mark S. [NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035 (United States); Saumon, Didier [Los Alamos National Laboratory, Mail Stop F663, Los Alamos, NM 87545 (United States); Cushing, Michael [Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Ackerman, Andrew S. [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Freedman, Richard, E-mail: Mark.S.Marley@NASA.gov, E-mail: dsaumon@lanl.gov, E-mail: michael.cushing@utoledo.edu, E-mail: andrew.ackerman@nasa.gov, E-mail: jfortney@ucolick.org, E-mail: freedman@darkstar.arc.nasa.gov [SETI Institute and NASA Ames Research Center, MS-245-3, Moffett Field, CA 94035 (United States)

2012-08-01T23:59:59.000Z

328

Ion beam surface treatment: A new technique for thermally modifying surfaces using intense, pulsed ion beams  

Science Conference Proceedings (OSTI)

The emerging capability to produce high average power (10--300 kW) pulsed ion beams at 0.2{minus}2 MeV energies is enabling us to develop a new, commercial-scale thermal surface treatment technology called Ion Beam Surface Treatment (IBEST). This new technique uses high energy, pulsed ({le}500 ns) ion beams to directly deposit energy in the top 1--20 micrometers of the surface of any material. The depth of treatment is controllable by varying the ion energy and species. Deposition of the energy in a thin surface layer allows melft of the layer with relatively small energies (1--10J/cm2) and allows rapid cooling of the melted layer by thermal conduction into the underlying substrate. Typical cooling rates of this process (109 K/sec) are sufficient to cause amorphous layer formation and the production of non-equilibrium microstructures (nanocrystalline and metastable phases). Results from initial experiments confirm surface hardening, amorphous layer and nanocrystalline grain size formation, corrosion resistance in stainless steel and aluminum, metal surface polishing, controlled melt of ceramic surfaces, and surface cleaning and oxide layer removal as well as surface ablation and redeposition. These results follow other encouraging results obtained previously in Russia using single pulse ion beam systems. Potential commercialization of this surface treatment capability is made possible by the combination of two new technologies, a new repetitive high energy pulsed power capability (0.2{minus}2MV, 25--50 kA, 60 ns, 120 Hz) developed at SNL, and a new repetitive ion beam system developed at Cornell University.

Stinnett, R.W.; Buchheit, R.G.; Neau, E.L. [and others

1995-08-01T23:59:59.000Z

329

Modeling of pulsating heat pipes.  

SciTech Connect

This report summarizes the results of a computer model that describes the behavior of pulsating heat pipes (PHP). The purpose of the project was to develop a highly efficient (as compared to the heat transfer capability of solid copper) thermal groundplane (TGP) using silicon carbide (SiC) as the substrate material and water as the working fluid. The objective of this project is to develop a multi-physics model for this complex phenomenon to assist with an understanding of how PHPs operate and to be able to understand how various parameters (geometry, fill ratio, materials, working fluid, etc.) affect its performance. The physical processes describing a PHP are highly coupled. Understanding its operation is further complicated by the non-equilibrium nature of the interplay between evaporation/condensation, bubble growth and collapse or coalescence, and the coupled response of the multiphase fluid dynamics among the different channels. A comprehensive theory of operation and design tools for PHPs is still an unrealized task. In the following we first analyze, in some detail, a simple model that has been proposed to describe PHP behavior. Although it includes fundamental features of a PHP, it also makes some assumptions to keep the model tractable. In an effort to improve on current modeling practice, we constructed a model for a PHP using some unique features available in FLOW-3D, version 9.2-3 (Flow Science, 2007). We believe that this flow modeling software retains more of the salient features of a PHP and thus, provides a closer representation of its behavior.

Givler, Richard C.; Martinez, Mario J.

2009-08-01T23:59:59.000Z

330

Interface physics in microporous media : LDRD final report.  

Science Conference Proceedings (OSTI)

This document contains a summary of the work performed under the LDRD project entitled 'Interface Physics in Microporous Media'. The presence of fluid-fluid interfaces, which can carry non-zero stresses, distinguishes multiphase flows from more readily understood single-phase flows. In this work the physics active at these interfaces has been examined via a combined experimental and computational approach. One of the major difficulties of examining true microporous systems of the type found in filters, membranes, geologic media, etc. is the geometric uncertainty. To help facilitate the examination of transport at the pore-scale without this complication, a significant effort has been made in the area of fabrication of both two-dimensional and three-dimensional micromodels. Using these micromodels, multiphase flow experiments have been performed for liquid-liquid and liquid-gas systems. Laser scanning confocal microscopy has been utilized to provide high resolution, three-dimensional reconstructions as well as time resolved, two-dimensional reconstructions. Computational work has focused on extending lattice Boltzmann (LB) and finite element methods for probing the interface physics at the pore scale. A new LB technique has been developed that provides over 100x speed up for steady flows in complex geometries. A new LB model has been developed that allows for arbitrary density ratios, which has been a significant obstacle in applying LB to air-water flows. A new reduced order model has been developed and implemented in finite element code for examining non-equilibrium wetting in microchannel systems. These advances will enhance Sandia's ability to quantitatively probe the rich interfacial physics present in microporous systems.

Yaklin, Melissa A.; Knutson, Chad E.; Noble, David R.; Aragon, Alicia R.; Chen, Ken Shuang; Giordano, Nicholas J. (Purdue University, West Lafayette, IN); Brooks, Carlton, F.; Pyrak-Nolte, Laura J. (Purdue University, West Lafayette, IN); Liu, Yihong (Purdue University, West Lafayette, IN)

2008-09-01T23:59:59.000Z

331

Investigation of the physical and numerical foundations of two-fluid representation of sodium boiling with applications to LMFBR experiments  

Science Conference Proceedings (OSTI)

This work involves the development of physical models for the constitutive relations of a two-fluid, three-dimensional sodium boiling code, THERMIT-6S. The code is equipped with a fluid conduction model, a fuel pin model, and a subassembly wall model suitable for stimulating LMFBR transient events. Mathematically rigorous derivations of time-volume averaged conservation equations are used to establish the differential equations of THERMIT-6S. These equations are then discretized in a manner identical to the original THERMIT code. A virtual mass term is incorporated in THERMIT-6S to solve the ill-posed problem. Based on a simplified flow regime, namely cocurrent annular flow, constitutive relations for two-phase flow of sodium are derived. The wall heat transfer coefficient is based on momentum-heat transfer analogy and a logarithmic law for liquid film velocity distribution. A broad literature review is given for two-phase friction factors. It is concluded that entrainment can account for some of the discrepancies in the literature. Mass and energy exchanges are modelled by generalization of the turbulent flux concept. Interfacial drag coefficients are derived for annular flows with entrainment. Code assessment is performed by simulating three experiments for low flow-high power accidents and one experiment for low flow/low power accidents in the LMFBR. While the numerical results for pre-dryout are in good agreement with the data, those for post-dryout reveal the need for improvement of the physical models. The benefits of two-dimensional non-equilibrium representation of sodium boiling are studied.

No, H.C.; Kazimi, M.S.

1983-03-01T23:59:59.000Z

332

Mesoscale Benchmark Demonstration Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing  

SciTech Connect

A study was conducted to evaluate the capabilities of different numerical methods used to represent microstructure behavior at the mesoscale for irradiated material using an idealized benchmark problem. The purpose of the mesoscale benchmark problem was to provide a common basis to assess several mesoscale methods with the objective of identifying the strengths and areas of improvement in the predictive modeling of microstructure evolution. In this work, mesoscale models (phase-field, Potts, and kinetic Monte Carlo) developed by PNNL, INL, SNL, and ORNL were used to calculate the evolution kinetics of intra-granular fission gas bubbles in UO2 fuel under post-irradiation thermal annealing conditions. The benchmark problem was constructed to include important microstructural evolution mechanisms on the kinetics of intra-granular fission gas bubble behavior such as the atomic diffusion of Xe atoms, U vacancies, and O vacancies, the effect of vacancy capture and emission from defects, and the elastic interaction of non-equilibrium gas bubbles. An idealized set of assumptions was imposed on the benchmark problem to simplify the mechanisms considered. The capability and numerical efficiency of different models are compared against selected experimental and simulation results. These comparisons find that the phase-field methods, by the nature of the free energy formulation, are able to represent a larger subset of the mechanisms influencing the intra-granular bubble growth and coarsening mechanisms in the idealized benchmark problem as compared to the Potts and kinetic Monte Carlo methods. It is recognized that the mesoscale benchmark problem as formulated does not specifically highlight the strengths of the discrete particle modeling used in the Potts and kinetic Monte Carlo methods. Future efforts are recommended to construct increasingly more complex mesoscale benchmark problems to further verify and validate the predictive capabilities of the mesoscale modeling methods used in this study.

Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert; Gao, Fei; Sun, Xin; Tonks, Michael; Biner, Bullent; Millet, Paul; Tikare, Veena; Radhakrishnan, Balasubramaniam; Andersson , David

2012-04-11T23:59:59.000Z

333

LABORATORY ANALYSIS OF PRESOLAR SILICATE STARDUST FROM A NOVA  

Science Conference Proceedings (OSTI)

We report the major element as well as the oxygen, magnesium, and silicon isotope composition of a unique presolar silicate grain found in the fine-grained fraction of the Antarctic CR2 chondrite Graves Nunataks 95229. The grain is characterized by an extremely high {sup 17}O/{sup 16}O ratio (6.3 {+-} 0.2 Multiplication-Sign 10{sup -3}) relative to solar values, whereas its {sup 18}O/{sup 16}O ratio is solar within measurement uncertainty. It also shows enrichments in {sup 25,26}Mg and a significant excess in {sup 30}Si relative to solar system compositions, with {delta}{sup 25}Mg = 79 {+-} 21 per mille , {delta}{sup 26}Mg = 70 {+-} 20 per mille , and {delta}{sup 30}Si = 379 {+-} 92 per mille . This isotopic composition is consistent with an origin in the ejecta of a {approx}1.3-1.4 M{sub Sun} ONe nova with large contributions of material from a main-sequence companion star of roughly solar metallicity. However, many details of the stellar source remain undetermined, owing to the uncertainties of current nova nucleosynthesis models. Auger electron spectroscopic analyses identify O, Mg, Si, and Fe as the grain's major constituents. Its (Mg+Fe)/Si atomic ratios are lower than that of olivine and correspond on average to Fe-Mg-pyroxene. A complex texture and heterogeneous major element distribution within the grain attest to condensation under non-equilibrium conditions, which is consistent with the proposed nova origin.

Leitner, J.; Kodolanyi, J.; Hoppe, P. [Max Planck Institute for Chemistry, Particle Chemistry Department, Hahn-Meitner-Weg 1, D-55128 Mainz (Germany); Floss, C., E-mail: jan.leitner@mpic.de [Laboratory for Space Sciences and Physics Department, Washington University, One Brookings Drive, St. Louis, MO 63130 (United States)

2012-08-01T23:59:59.000Z

334

TEMperature Pressure ESTimation of a homogeneous boiling fuel-steel mixture in an LMFBR core. [TEMPEST code  

SciTech Connect

The paper describes TEMPEST, a simple computer program for the temperature and pressure estimation of a boiling fuel-steel pool in an LMFBR core. The time scale of interest of this program is large, of the order of ten seconds. Further, the vigorous boiling in the pool will generate a large contact, and hence a large heat transfer between fuel and steel. The pool is assumed to be a uniform mixture of fuel and steel, and consequently vapor production is also assumed to be uniform throughout the pool. The pool is allowed to expand in volume if there is steel melting at the walls. In this program, the total mass of liquid and vapor fuel is always kept constant, but the total steel mass in the pool may change by steel wall melting. Because of a lack of clear understanding of the physical phenomena associated with the progression of a fuel-steel mixture at high temperature, various input options have been built-in to enable one to perform parametric studies. For example, the heat transfer from the pool to the surrounding steel structure may be controlled by input values for the heat transfer coefficients, or, the heat transfer may be calculated by a correlation obtained from the literature. Similarly, condensation of vapor on the top wall can be specified by input values of the condensation coefficient; the program can otherwise calculate condensation according to the non-equilibrium model predictions. Meltthrough rates of the surrounding steel walls can be specified by a fixed melt-rate or can be determined by a fraction of the heat loss that goes to steel-melting. The melted steel is raised to the pool temperature before it is joined with the pool material. Several applications of this program to various fuel-steel pools in the FFTF and the CRBR cores are discussed.

Pyun, J.J.; Majumdar, D.

1976-11-01T23:59:59.000Z

335

Agent-based computational models and generative social science  

E-Print Network (OSTI)

This article argues that the agent-based computational model permits a distinctive approach to social science for which the term generative is suitable. In defending this terminology, features distinguishing the approach from both inductive and deductive science are given. Then, the following specific contributions to social science are discussed: The agent-based computational model is a new tool for empirical research. It offers a natural environment for the study of connectionist phenomena in social science. Agent-based modeling provides a powerful way to address certain enduringand especially interdisciplinaryquestions. It allows one to subject certain core theoriessuch as neoclassical microeconomicsto important types of stress (e.g., the effect of evolving preferences). It permits one to study how rules of individual behavior give riseor map upto macroscopic regularities and organizations. In turn, one can employ laboratory behavioral research findings to select among competing agent-based (bottom up) models. The agent-based approach may well have the important effect of decoupling individual rationality from macroscopic equilibrium and of separating decision science from social science more generally. Agent-based modeling offers powerful new forms of hybrid theoretical-computational work; these are particularly relevant to the study of non-equilibrium systems. The agentbased approach invites the interpretation of society as a distributed computational device, and in turn the interpretation of social dynamics as a type of computation. This interpretation raises important foundational issues in social sciencesome related to intractability, and some to undecidability proper. Finally, since emergence figures prominently in this literature, I take up the connection between agent-based modeling and classical emergentism, criticizing the latter and arguing that the two are incompatible. ? 1999 John Wiley &

Joshua M. Epstein

1999-01-01T23:59:59.000Z

336

Thermal evolution behavior of carbides and {gamma} Prime precipitates in FGH96 superalloy powder  

SciTech Connect

The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and {gamma} Prime precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02-2.55 {mu}m and the corresponding cooling rates were estimated to be in the range of 1.4 Multiplication-Sign 10{sup 4}-4.7 Multiplication-Sign 10{sup 5} K{center_dot}s{sup -1}. An increase in the annealing temperature had rendered the phase transformation of carbides evolving from non-equilibrium MC Prime carbides to intermediate transition stage of M{sub 23}C{sub 6} carbides, and finally to thermodynamically stable MC carbides. The superfine {gamma} Prime precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of {gamma}' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 Degree-Sign C{center_dot}K{sup -1} to 5 Degree-Sign C{center_dot}K{sup -1}, the morphological development of {gamma} Prime precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 Degree-Sign C and 1050 Degree-Sign C. Moreover, accelerated evolution of carbides and {gamma}' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: Black-Right-Pointing-Pointer Microstructural characteristic of FGH96 superalloy powder was investigated. Black-Right-Pointing-Pointer The relation between microstructure, particle size, and cooling rate was studied. Black-Right-Pointing-Pointer Thermal evolution behavior of {gamma} Prime and carbides in loose FGH96 powder was studied.

Zhang Lin, E-mail: zhanglincsu@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Liu Hengsan, E-mail: lhsj63@sohu.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); He Xinbo, E-mail: xb_he@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Rafi-ud-din, E-mail: rafiuddi@gmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qu Xuanhui, E-mail: quxh@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qin Mingli, E-mail: mlqin75@hotmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Li Zhou, E-mail: zhouli621@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China); Zhang Guoqing, E-mail: g.zhang@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China)

2012-05-15T23:59:59.000Z

337

Vacuum quantum fluctuation energy in expanding universe and dark energy  

E-Print Network (OSTI)

This article is based on the Planckon densely piled vacuum model and the principle of cosmology. With Planck era as initial conditions and including early inflation, we have solved the Einstein-Friedmann equations to describe the evolution of the universe, a reasonable relation between dark energy density and vacuum quantum fluctuation energy density is obtained. The main results are : 1) the solution of Einstein-Friedmann equations has yielded the result $\\frac{{{\\rho}_{de}}}{{{\\rho}_{vac}}}\\sim{{(\\frac{{{t}_{P}}}{{{T}_{0}}})}^{2}}\\sim{{10}^{-122}} $ (Planck time ${{t}_{P}}={{10}^{-43}}s$ and universe age ${{T}_{0}}={{10}^{18}}s$);2) at inflation time ${{t}_{\\inf}}={{10}^{-35}}s$, the calculated universe radiation energy density is $\\rho ({{t}_{\\inf}})\\sim{{10}^{-16}}{{\\rho}_{vac}}$ and the corresponding temperature is ${{E}_{c}}\\sim{{10}^{15}}GeV$ consistent with GUT phase transition temperature;3) it is showed that the expanding universe is a non-equilibrium open system constantly exchanging energy with vacuum; during its expanding, the Planckons in universe lose quantum fluctuation energy and create cosmic expansion quanta-cosmons, the energy of cosmons is the lost part of vacuum quantum fluctuation energy and contributes to the total energy of the universe with the calculated value ${{E}_{\\cos mos}}={{10}^{22}}{{M}_{\\otimes}}{{c}^{2}}$ (${{M}_{\\otimes}}$ is solar mass) agreed with astronomic data; 4) the gravity potential and gravity acceleration of cosmons are derived with the nature of repulsive force, indicating that the cosmon may be the candidate of dark energy quantum; 5) solution to three well known cosmic problems of Big Bang model is presented.

Shun-Jin Wang

2013-01-02T23:59:59.000Z

338

CHARACTERIZING TRANSITION TEMPERATURE GAS IN THE GALACTIC CORONA  

Science Conference Proceedings (OSTI)

We present a study of the properties of the transition temperature (T {approx} 10{sup 5} K) gas in the Milky Way corona, based on the measurements of O VI, N V, C IV, Si IV, and Fe III absorption lines seen in the far-ultraviolet spectra of 58 sight lines to extragalactic targets, obtained with the Far-Ultraviolet Spectroscopic Explorer and the Space Telescope Imaging Spectrograph. In many sight lines the Galactic absorption profiles show multiple components, which are analyzed separately. We find that the highly ionized atoms are distributed irregularly in a layer with a scale height of about 3 kpc, which rotates along with the gas in the disk, without an obvious gradient in the rotation velocity away from the Galactic plane. Within this layer the gas has randomly oriented velocities with a dispersion of 40-60 km s{sup -1}. On average the integrated column densities are log N(O VI) = 14.3, log N(N V) = 13.5, log N(C IV) = 14.2, log N(Si IV) = 13.6, and log N(Fe III) = 14.2, with a dispersion of just 0.2 dex in each case. In sight lines around the Galactic center and Galactic north pole, all column densities are enhanced by a factor {approx}2, while at intermediate latitudes in the southern sky there is a deficit in N(O VI) of about a factor of two, but no deficit for the other ions. We compare the column densities and ionic ratios to a series of theoretical predictions: collisional ionization equilibrium, shock ionization, conductive interfaces, turbulent mixing, thick disk supernovae, static non-equilibrium ionization (NIE) radiative cooling, and an NIE radiative cooling model in which the gas flows through the cooling zone. None of these models can fully reproduce the data, but it is clear that NIE radiative cooling is important in generating the transition temperature gas.

Wakker, Bart P.; Savage, Blair D. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Fox, Andrew J. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile); Benjamin, Robert A. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore MD 21218 (United States); Shapiro, Paul R., E-mail: wakker@astro.wisc.edu, E-mail: savage@astro.wisc.edu, E-mail: afox@stsci.edu, E-mail: benjamir@uww.edu, E-mail: shapiro@astro.as.utexas.edu [University of Texas at Austin, Department of Astronomy, Austin, TX 78712 (United States)

2012-04-20T23:59:59.000Z

339

FUNDAMENTAL PROPERTIES OF THE HIGHLY IONIZED PLASMAS IN THE MILKY WAY  

SciTech Connect

The cooling transition temperature gas in the interstellar medium (ISM), traced by the high ions, Si IV, C IV, N V, and O VI, helps to constrain the flow of energy from the hot ISM with T>10{sup 6} K to the warm ISM with T < 2 x 10{sup 4} K. We investigate the properties of this gas along the lines of sight to 38 stars in the Milky Way disk using 1.5-2.7 km s{sup -1} resolution spectra of Si IV, C IV, and N V absorption from the Space Telescope Imaging Spectrograph, and 15 km s{sup -1} resolution spectra of O VI absorption from the Far Ultraviolet Spectroscopic Explorer. The absorption by Si IV and C IV exhibits broad and narrow components while only broad components are seen in N V and O VI. The narrow components imply gas with T < 7 x 10{sup 4} K and trace two distinct types of gas. The strong, saturated, and narrow Si IV and C IV components trace the gas associated with the vicinities of O-type stars and their supershells. The weaker narrow Si IV and C IV components trace gas in the general ISM that is photoionized by the EUV radiation from cooling hot gas or has radiatively cooled in a non-equilibrium manner from the transition temperature phase, but rarely the warm-ionized medium probed by Al III. The broad Si IV, C IV, N V, and O VI components trace collisionally ionized gas that is very likely undergoing a cooling transition from the hot ISM to the warm ISM. The cooling process possibly provides the regulation mechanism that produces (N(C IV)/N(Si IV)) = 3.9 {+-} 1.9. The cooling process also produces absorption lines where the median and mean values of the line widths increase with the energy required to create the ion.

Lehner, N.; Zech, W. F.; Howk, J. C. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Savage, B. D. [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States)

2011-01-20T23:59:59.000Z

340

Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b  

SciTech Connect

Using the integral field spectrograph OSIRIS, on the Keck II telescope, broad near-infrared H and K-band spectra of the young exoplanet HR8799b have been obtained. In addition, six new narrow-band photometric measurements have been taken across the H and K bands. These data are combined with previously published photometry for an analysis of the planet's atmospheric properties. Thick photospheric dust cloud opacity is invoked to explain the planet's red near-IR colors and relatively smooth near-IR spectrum. Strong water absorption is detected, indicating a Hydrogen-rich atmosphere. Only weak CH{sub 4} absorption is detected at K band, indicating efficient vertical mixing and a disequilibrium CO/CH{sub 4} ratio at photospheric depths. The H-band spectrum has a distinct triangular shape consistent with low surface gravity. New giant planet atmosphere models are compared to these data with best fitting bulk parameters, T{sub eff} = 1100K {+-} 100 and log(g) = 3.5 {+-} 0.5 (for solar composition). Given the observed luminosity (log L{sub obs}/L{sub {circle_dot}} {approx} -5.1), these values correspond to a radius of 0.75 R{sub Jup{sub 0.12}{sup +0.17}} and mass {approx} 0.72 M{sub Jup{sub -0.6}{sup +2.6}} - strikingly inconsistent with interior/evolution models. Enhanced metallicity (up to {approx} 10 x that of the Sun) along with thick clouds and non-equilibrium chemistry are likely required to reproduce the complete ensemble of spectroscopic and photometric data and the low effective temperatures (< 1000K) required by the evolution models.

Barman, T S; Macintosh, B A; Konopacky, Q M; Marois, C

2011-03-21T23:59:59.000Z

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341

Probing the relaxation towards equilibrium in an isolated strongly correlated 1D Bose gas  

E-Print Network (OSTI)

The problem of how complex quantum systems eventually come to rest lies at the heart of statistical mechanics. The maximum entropy principle put forward in 1957 by E. T. Jaynes suggests what quantum states one should expect in equilibrium but does not hint as to how closed quantum many-body systems dynamically equilibrate. A number of theoretical and numerical studies accumulate evidence that under specific conditions quantum many-body models can relax to a situation that locally or with respect to certain observables appears as if the entire system had relaxed to a maximum entropy state. In this work, we report the experimental observation of the non-equilibrium dynamics of a density wave of ultracold bosonic atoms in an optical lattice in the regime of strong correlations. Using an optical superlattice, we are able to prepare the system in a well-known initial state with high fidelity. We then follow the dynamical evolution of the system in terms of quasi-local densities, currents, and coherences. Numerical studies based on the time-dependent density-matrix renormalization group method are in an excellent quantitative agreement with the experimental data. For very long times, all three local observables show a fast relaxation to equilibrium values compatible with those expected for a global maximum entropy state. We find this relaxation of the quasi-local densities and currents to initially follow a power-law with an exponent being significantly larger than for free or hardcore bosons. For intermediate times the system fulfills the promise of being a dynamical quantum simulator, in that the controlled dynamics runs for longer times than present classical algorithms based on matrix product states can efficiently keep track of.

Stefan Trotzky; Yu-Ao Chen; Andreas Flesch; Ian P. McCulloch; Ulrich Schollwck; Jens Eisert; Immanuel Bloch

2011-01-13T23:59:59.000Z

342

THREE-DIMENSIONAL SIMULATIONS OF THE THERMAL X-RAY EMISSION FROM YOUNG SUPERNOVA REMNANTS INCLUDING EFFICIENT PARTICLE ACCELERATION  

Science Conference Proceedings (OSTI)

Supernova remnants (SNRs) are believed to be the major contributors to Galactic cosmic rays. The detection of non-thermal emission from SNRs demonstrates the presence of energetic particles, but direct signatures of protons and other ions remain elusive. If these particles receive a sizeable fraction of the explosion energy, the morphological and spectral evolution of the SNR must be modified. To assess this, we run three-dimensional hydrodynamic simulations of a remnant coupled with a nonlinear acceleration model. We obtain the time-dependent evolution of the shocked structure, impacted by the Rayleigh-Taylor hydrodynamic instabilities at the contact discontinuity and by the back-reaction of particles at the forward shock. We then compute the progressive temperature equilibration and non-equilibrium ionization state of the plasma, and its thermal emission in each cell. This allows us to produce the first realistic synthetic maps of the projected X-ray emission from the SNR. Plasma conditions (temperature and ionization age) can vary widely over the projected surface of the SNR, especially between the ejecta and the ambient medium owing to their different composition. This demonstrates the need for spatially resolved spectroscopy. We find that the integrated emission is reduced with particle back-reaction, with the effect being more significant for the highest photon energies. Therefore, different energy bands, corresponding to different emitting elements, probe different levels of the impact of particle acceleration. Our work provides a framework for the interpretation of SNR observations with current X-ray missions (Chandra, XMM-Newton, and Suzaku) and with upcoming X-ray missions (such as Astro-H).

Ferrand, Gilles; Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg MB R3T 2N2 (Canada); Decourchelle, Anne, E-mail: gferrand@physics.umanitoba.ca, E-mail: samar@physics.umanitoba.ca, E-mail: anne.decourchelle@cea.fr [Laboratoire AIM (CEA/Irfu, CNRS/INSU, Universite Paris VII), CEA Saclay, bat. 709, F-91191 Gif sur Yvette (France)

2012-11-20T23:59:59.000Z

343

Probability density function method for variable-density pressure-gradient-driven turbulence and mixing  

SciTech Connect

Probability density function (PDF) methods are extended to variable-density pressure-gradient-driven turbulence. We apply the new method to compute the joint PDF of density and velocity in a non-premixed binary mixture of different-density molecularly mixing fluids under gravity. The full time-evolution of the joint PDF is captured in the highly non-equilibrium flow: starting from a quiescent state, transitioning to fully developed turbulence and finally dissipated by molecular diffusion. High-Atwood-number effects (as distinguished from the Boussinesq case) are accounted for: both hydrodynamic turbulence and material mixing are treated at arbitrary density ratios, with the specific volume, mass flux and all their correlations in closed form. An extension of the generalized Langevin model, originally developed for the Lagrangian fluid particle velocity in constant-density shear-driven turbulence, is constructed for variable-density pressure-gradient-driven flows. The persistent small-scale anisotropy, a fundamentally 'non-Kolmogorovian' feature of flows under external acceleration forces, is captured by a tensorial diffusion term based on the external body force. The material mixing model for the fluid density, an active scalar, is developed based on the beta distribution. The beta-PDF is shown to be capable of capturing the mixing asymmetry and that it can accurately represent the density through transition, in fully developed turbulence and in the decay process. The joint model for hydrodynamics and active material mixing yields a time-accurate evolution of the turbulent kinetic energy and Reynolds stress anisotropy without resorting to gradient diffusion hypotheses, and represents the mixing state by the density PDF itself, eliminating the need for dubious mixing measures. Direct numerical simulations of the homogeneous Rayleigh-Taylor instability are used for model validation.

Bakosi, Jozsef [Los Alamos National Laboratory; Ristorcelli, Raymond J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

344

Aging through hierarchical coalescence in the East model  

E-Print Network (OSTI)

We rigorously analyze the low temperature non-equilibrium dynamics of the East model, a special example of a one dimensional oriented kinetically constrained particle model, when the initial distribution is different from the reversible one and for times much smaller than the global relaxation time. This setting has been intensively studied in the physics literature to analyze the slow dynamics which follows a sudden quench from the liquid to the glass phase. In the limit of zero temperature (i.e. a vanishing density of vacancies) and for initial distributions such that the vacancies form a renewal process we prove that the density of vacancies, the persistence function and the two-time autocorrelation function behave as staircase functions with several plateaux. Furthermore the two-time autocorrelation function displays an aging behavior. We also provide a sharp description of the statistics of the domain length as a function of time, a domain being the interval between two consecutive vacancies. When the initial renewal process has finite mean our results confirm (and generalize) previous findings of the physicists for the restricted case of a product Bernoulli measure. However we show that a different behavior appears when the initial domain distribution is in the attraction domain of a $\\alpha$-stable law. All the above results actually follow from a more general result which says that the low temperature dynamics of the East model is very well described by that of a certain hierarchical coalescence process, a probabilistic object which can be viewed as a hierarchical sequence of suitably linked coalescence processes and whose asymptotic behavior has been recently studied in [14].

A. Faggionato; F. Martinelli; C. Roberto; C. Toninelli

2010-12-22T23:59:59.000Z

345

MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization  

SciTech Connect

The power of magnetic resonance imaging (MRI) is its ability to image the internal structure of optically opaque samples and provide detailed maps of a variety of important parameters, such as density, diffusion, velocity and temperature. However, one of the fundamental limitations of this technique is its inherent low sensitivity. For example, the low signal to noise ratio (SNR) is particularly problematic for imaging gases in porous materials due to the low density of the gas and the large volume occluded by the porous material. This is unfortunate, as many industrially relevant chemical reactions take place at gas-surface interfaces in porous media, such as packed catalyst beds. Because of this severe SNR problem, many techniques have been developed to directly increase the signal strength. These techniques work by manipulating the nuclear spin populations to produce polarized} (i.e., non-equilibrium) states with resulting signal strengths that are orders of magnitude larger than those available at thermal equilibrium. This dissertation is concerned with an extension of a polarization technique based on the properties of parahydrogen. Specifically, I report on the novel use of heterogeneous catalysis to produce parahydrogen induced polarization and applications of this new technique to gas phase MRI and the characterization of micro-reactors. First, I provide an overview of nuclear magnetic resonance (NMR) and how parahydrogen is used to improve the SNR of the NMR signal. I then present experimental results demonstrating that it is possible to use heterogeneous catalysis to produce parahydrogen-induced polarization. These results are extended to imaging void spaces using a parahydrogen polarized gas. In the second half of this dissertation, I demonstrate the use of parahydrogen-polarized gas-phase MRI for characterizing catalytic microreactors. Specifically, I show how the improved SNR allows one to map parameters important for characterizing the heat and mass transport in a heterogeneous catalyst bed. This is followed by appendices containing detailed information regarding the design and use of my experimental setup.

Burt, Scott R; Burt, Scott R.

2008-06-25T23:59:59.000Z

346

Spontaneous motion in hierarchically assembled active matter  

E-Print Network (OSTI)

With exquisite precision and reproducibility, cells orchestrate the cooperative action of thousands of nanometer-sized molecular motors to carry out mechanical tasks at much larger length scales, such as cell motility, division and replication. Besides their biological importance, such inherently non-equilibrium processes are an inspiration for developing biomimetic active materials from microscopic components that consume energy to generate continuous motion. Being actively driven, these materials are not constrained by the laws of equilibrium statistical mechanics and can thus exhibit highly sought-after properties such as autonomous motility, internally generated flows and self-organized beating. Starting from extensile microtubule bundles, we hierarchically assemble active analogs of conventional polymer gels, liquid crystals and emulsions. At high enough concentration, microtubules form a percolating active network characterized by internally driven chaotic flows, hydrodynamic instabilities, enhanced transport and fluid mixing. When confined to emulsion droplets, 3D networks spontaneously adsorb onto the droplet surfaces to produce highly active 2D nematic liquid crystals whose streaming flows are controlled by internally generated fractures and self-healing, as well as unbinding and annihilation of oppositely charged disclination defects. The resulting active emulsions exhibit unexpected properties, such as autonomous motility, which are not observed in their passive analogues. Taken together, these observations exemplify how assemblages of animate microscopic objects exhibit collective biomimetic properties that are starkly different from those found in materials assembled from inanimate building blocks, challenging us to develop a theoretical framework that would allow for a systematic engineering of their far-from-equilibrium material properties.

Tim Sanchez; Daniel T. N. Chen; Stephen J. DeCamp; Michael Heymann; Zvonimir Dogic

2013-01-07T23:59:59.000Z

347

Revisiting the effect of H2, HD and LiH molecules in the cooling of primordial gas  

E-Print Network (OSTI)

We use a non-equilibrium chemical network to revisit and study the effect of H_{2}, HD and LiH molecular cooling on a primordial element of gas. We solve both the thermal and chemical equations for a gas element with an initial temperature T\\approx 1000K and a gas number density in the range n_{tot}=1-10^{4} cm^{-3}. At low densities, n_{tot}gas reaches temperatures \\sim 100K and the main coolant is H_{2}, but at higher densities, n_{tot}>10^{2} cm^{-3}, the HD molecule dominates the gas temperature evolution. The effect of LiH is negligible in all cases. We studied the effect of D abundance on the gas cooling. The D abundance was set initially to be in the range n_{D}/n_{H}=10^{-7}-10^{-4.5}, with n_{HD}/n_{H}={D^{+}}/n_{H}=10^{-10}. The simulations show that at n_{tot}>10^{2} cm^{-3} the HD cooling dominates the temperature evolution for D abundances greater than 10^{-5}n_{H}. This number decrease at higher densities. Furthermore, we studied the effect of electrons and ionized particules on the gas temperature. We followed the gas temperature evolution with n_{H_{+}}/n_{H}=10^{-4}-10^{-1} and n_{D^{+}}/n_{H^{+}}=10^{-5}. The gas temperature reached lower values at high ionization degree because electrons, H^{+} and D^{+} are catalizers in the formation paths of the H_{2} and HD molecules, which are the main coolers at low temperatures. Finaly, we studied the effect of an OB star, with T_{eff}=4\\times 10^{4}K, would have on gas cooling. It is very difficult for a gas with n_{tot} in the range between 1-100 cm^{-3} to drop its temperature if the star is at a distance less than 100 pc.

Joaquin P. Prieto; Leopoldo Infante; Raul Jimenez

2008-09-16T23:59:59.000Z

348

Advanced Laser Diagnostics Development for the Characterization of Gaseous High Speed Flows  

E-Print Network (OSTI)

The study of high-speed flows represents a challenging problem in the fluid dynamics field due to the presence of chemical reactions and non-equilibrium effects. Hypersonic flights, where speeds reach Mach 5 and above, are particularly influenced by these effects, resulting in a direct impact on the flow and consequently on the aerodynamic performance of a vehicle traveling at these speeds. The study of hypersonic flow conditions requires the experimental capability of determining local temperatures, pressures and velocities using non-intrusive techniques. Furthermore, the simultaneous measurement of two or more variables in a complex flow boosts the amount of information that is obtained since valuable correlations can be established. This research includes the design, construction and characterization of a hypersonic flow apparatus explicitly intended as a tool for advanced laser diagnostics development. This apparatus is characterized by its pulsed operation mode that translates into a significant reduction in mass flow rates and can be operated for long periods at Mach numbers ranging from 2.8 to 6.2. The flow conditions during the uniform flow time interval of each pulse vary by less than 1%, generating a flow of sufficient quality for quantitative measurements. The development of a laser diagnostic technique, the VENOM technique, which is a non-intrusive method to provide simultaneous 2-D measurements of the mean and instantaneous fluctuations in two-component velocity and temperature is also presented. This technique represents the first single diagnostic capable of instantaneous two-component velocimetry and thermometry in a gaseous flow field by combining two Nitric Oxide Planar Laser Induced Fluorescence methods: two-component Molecular Tagging Velocimetry and two-line thermometry, employing the nascent NO(v"=1) arising from the NO2 photodissociation as a molecular tracer. The VENOM technique is expected to be not only applicable to cold high-speed flows, which is the focus of the present work, but also to combustion and other reactive or high-enthalpy flow fields.

Sanchez-Gonzalez, Rodrigo

2012-05-01T23:59:59.000Z

349

ADVANCED STEAM GENERATORS  

SciTech Connect

Concerns about climate change have encouraged significant interest in concepts for ultra-low or ''zero''-emissions power generation systems. In some proposed concepts, nitrogen is removed from the combustion air and replaced with another diluent such as carbon dioxide or steam. In this way, formation of nitrogen oxides is prevented, and the exhaust stream can be separated into concentrated CO{sub 2} and steam or water streams. The concentrated CO{sub 2} stream could then serve as input to a CO{sub 2} sequestration process or utilized in some other way. Some of these concepts are illustrated in Figure 1. This project is an investigation of one approach to ''zero'' emission power generation. Oxy-fuel combustion is used with steam as diluent in a power cycle proposed by Clean Energy Systems, Inc. (CES) [1,2]. In oxy-fuel combustion, air separation is used to produce nearly pure oxygen for combustion. In this particular concept, the combustion temperatures are moderated by steam as a diluent. An advantage of this technique is that water in the product stream can be condensed with relative ease, leaving a pure CO{sub 2} stream suitable for sequestration. Because most of the atmospheric nitrogen has been separated from the oxidant, the potential to form any NOx pollutant is very small. Trace quantities of any minor pollutants species that do form are captured with the CO{sub 2} or can be readily removed from the condensate. The result is a nearly zero-emission power plant. A sketch of the turbine system proposed by CES is shown in Figure 2. NETL is working with CES to develop a reheat combustor for this application. The reheat combustion application is unusual even among oxy-fuel combustion applications. Most often, oxy-fuel combustion is carried out with the intent of producing very high temperatures for heat transfer to a product. In the reheat case, incoming steam is mixed with the oxygen and natural gas fuel to control the temperature of the output stream to about 1480 K. A potential concern is the possibility of quenching non-equilibrium levels of CO or unburned fuel in the mixing process. Inadequate residence times in the combustor and/or slow kinetics could possibly result in unacceptably high emissions. Thus, the reheat combustor design must balance the need for minimal excess oxygen with the need to oxidize the CO. This paper will describe the progress made to date in the design, fabrication, and simulation of a reheat combustor for an advanced steam generator system, and discuss planned experimental testing to be conducted in conjunction with NASA Glenn Research Center-Plumb Brook Station.

Richards, Geo. A.; Casleton, Kent H.; Lewis, Robie E.; Rogers, William A. (U.S. DOE National Energy Technology Laboratory); Woike, Mark R.; Willis; Brian P. (NASA Glenn Research Center)

2001-11-06T23:59:59.000Z

350

Incorporation of Integral Fuel Burnable Absorbers Boron and Gadolinium into Zirconium-Alloy Fuel Clad Material  

SciTech Connect

Long-lived fuels require the use of higher enrichments of 235U or other fissile materials. Such high levels of fissile material lead to excessive fuel activity at the beginning of life. To counteract this excessive activity, integral fuel burnable absorbers (IFBA) are added to some rods in the fuel assembly. The two commonly used IFBA elements are gadolinium, which is added as gadolinium-oxide to the UO2 powder, and boron, which is applied as a zirconium-diboride coating on the UO2 pellets using plasma spraying or chemical vapor deposition techniques. The incorporation of IFBA into the fuel has to be performed in a nuclear-regulated facility that is physically separated from the main plant. These operations tend to be very costly because of their small volume and can add from 20 to 30% to the manufacturing cost of the fuel. Other manufacturing issues that impact cost and performance are maintaining the correct levels of dosing, the reduction in fuel melting point due to gadolinium-oxide additions, and parasitic neutron absorption at fuel's end-of-life. The goal of the proposed research is to develop an alternative approach that involves incorporation of boron or gadolinium into the outer surface of the fuel cladding material rather than as an additive to the fuel pellets. This paradigm shift will allow for the introduction of the IFBA in a non-nuclear regulated environment and will obviate the necessity of additional handling and processing of the fuel pellets. This could represent significant cost savings and potentially lead to greater reproducibility and control of the burnable fuel in the early stages of the reactor operation. The surface alloying is being performed using the IBEST (Ion Beam Surface Treatment) process developed at Sandia National Laboratories. IBEST involves the delivery of energetic ion beam pulses onto the surface of a material, near-surface melting, and rapid solidification. The non-equilibrium nature of such processing allows for surface alloying well in excess of the thermodynamically dictated solubility limits, an effect that is particularly relevant to this research due to the negligible solubility of boron and gadolinium in zirconium. University of Wisconsin is performing the near surface materials characterization and analysis, aiding Sandia in process optimization, and promoting educational activities. Westinghouse is performing process manufacturability and scale-up analysis and is performing autoclave testing of the surface treated samples. The duration of this NERI project is 2 years, from 9/2002 to 9/2004.

Sridharan, K.; Renk, T.J.; Lahoda, E.J.; Corradini, M.L

2004-12-14T23:59:59.000Z

351

Final Report  

SciTech Connect

OAK B135 The formation of metastable crystalline phases in lithium disilicate glass has been a subject of controversy for decades. Here, one aspect of this problem relating to the stability of these non-equilibrium phases when glasses are heated for extended time periods in the nucleation regime is addressed. The results of a systematic experimental investigation on the persistence of metastable phases and the factors that may influence the appearance of such phases, e.g., water content, impurities, glass composition, and glass preparation procedure are presented. Growth rates of lithium disilicate crystals in lithium disilicate glass are measured as a function water concentration in the glass and of temperature in the deeply undercooled regime. The growth rate data obtained in this work are combined with data reported in the literature and used to assess the applicability of standard models of crystal growth for the description of experimental results over a very broad temperature range. The reduced growth rate versus undercooling graph is found to consist of three regimes. For undercoolings less than 140C, the reduced growth rate curve is suggestive of either 2-D surface nucleation or screw dislocation growth. For undercoolings greater than 400C, the reduced growth rate plot suggests the operative crystal growth mechanism is 2-D surface nucleation, but detailed calculations cast doubt upon this conclusion. In the intermediate undercooling range, there appears to be some sort of transitional behavior for which none of the standard models appear to be applicable. Further, it is observed that small differences in the viscosity data employed can produce enormous differences in the predicted growth rates at larger undercoolings. Results of the kinetic analyses conducted herein seem to indicate that the nature of the kinetic rate coefficient used in the standard growth models may be incorrect. Nucleation rates of sodium metasilicate crystals in a sodium silicate glass of composition 43Na2O-57SiO2 (mol%) are investigated using the development technique. The results of this study are compared with the nucleation rate results recently obtained for this composition using a novel DTA method. The two techniques are found to agree within experimental error.

Michael C. Weinberg; Lori L. Burgner; Joseph H. Simmons

2003-05-23T23:59:59.000Z

352

A NOVEL MEMBRANE REACTOR FOR DIRECT HYDROGEN PRODUCTION FROM COAL  

DOE Green Energy (OSTI)

Gas Technology Institute is developing a novel concept of membrane gasifier for high efficiency, clean and low cost production of hydrogen from coal. The concept incorporates a hydrogen-selective membrane within a gasification reactor for direct extraction of hydrogen from coal-derived synthesis gases. The objective of this project is to determine the technical and economic feasibility of this concept by screening, testing and identifying potential candidate membranes under high temperature, high pressure, and harsh environments of the coal gasification conditions. The best performing membranes will be selected for preliminary reactor design and cost estimates. To evaluate the performances of the candidate membranes under the gasification conditions, a high temperature/high pressure hydrogen permeation unit has been constructed in this project. During this reporting period, the unit has been fully commissioned and is operational. The unit is capable of operating at temperatures up to 1100 C and pressures to 60 atm for evaluation of ceramic membranes such as mixed ionic conducting membrane. A double-seal technique has been developed and tested successfully to achieve leak-tight seal for the membranes. Initial data for a commercial Palladium-Gold membrane were obtained at temperatures to 450 C and pressures to 13 atm. Tests for the perovskite membranes are being performed and the results will be reported in the next quarter. A membrane gasification reactor model was developed to consider the H{sub 2} permeability of the membrane, the kinetics and the equilibriums of the gas phase reactions in the gasifier, the operating conditions and the configurations of the membrane reactor. The results show that the hydrogen production efficiency using the novel membrane gasification reactor concept can be increased by about 50% versus the conventional gasification process. This confirms the previous evaluation results from the thermodynamic equilibrium calculation. A rigorous model for hydrogen permeation through mixed proton-electron conducting ceramic membranes was also developed based on non-equilibrium thermodynamics. The results from the simulation work confirm that the hydrogen flux increases with increasing partial pressure of hydrogen. The presence of steam in the permeate side can have a small negative effect on the hydrogen flux, in the order of 10%. When the steam partial pressure is greater than 1 atm, the hydrogen flux becomes independent of the steam pressure.

Shain Doong; Estela Ong; Mike Atroshenko; Francis Lau; Mike Roberts

2004-07-29T23:59:59.000Z

353

Electron Doping by Charge Transfer at LaFeO 3 /Sm 2 CuO 4 Epitaxial Interfaces  

SciTech Connect

The breakdown of the lattice translational invariance symmetry that occurs at complex oxide interfaces may profoundly modify their electronic structure, leading to interfacial states with properties drastically different from those of the superlattice individual components. The appearance of a conducting two dimensional (2D) electron gas at the interface between two insulating oxides and induced magnetism in a non-magnetic material are just two among many fascinating examples. [ 1 8 ] One of the key factors underlying novel properties is the modifi cation of the doping and orbital occupancy near those interfaces, which may result from charge transfer processes. [ 3 , 9 11 ] If materials used in heterostructures have different work functions, a non-equilibrium situation will be created at the interface and charge will be transferred until the chemical potential levels off. [ 12 ] The use of such phenomena to modify doping in heterostructures has been proposed theoretically as a new route to avoid the quenched disorder that inevitably accompanies the chemical doping. At the interface between a Mott insulating parent compound of the high critical temperature superconductor (HTSC) family and a suitable material that would act as the charge donor, electron doped phases could be stabilized which would eventually turn metallic and perhaps superconducting. [ 12 , 13 ] Such charge transfer processes have been observed at interfaces involving copper oxides such as La 0.7 Ca 0.3 MnO 3 / YBa 2 Cu 3 O 7 , [ 14 ] La 2 x Sr x CuO 4 /La 2 CuO 4 [ 15 ] and SrTi 1 x Nb x O 3 / Sm 2 CuO 4 . [ 16 ] While a novel 2D superconducting state was found at the La 2-x Sr x CuO 4 /La 2 CuO 4 interface, [ 17 ] the effect of doping by charge transfer could not be examined in the other two cases due to the detrimental effect on the YBa 2 Cu 3 O 7 superconductivity of the spin polarized electrons from La 0.7 Ca 0.3 MnO 3 in one case and due to the conducting nature of the SrTi 1 x Nb x O 3 in the other case, which obscures changes in the conducting properties of the interface layer. In this paper, the structural and

Bruno, Flavio Y. [Universidad Complutense, Spain; Schmidt, R [Universidad Complutense de Madrid, Spain; Varela, Maria [UCM, Dept Fis Aplicada 3, Madrid, Spain; Garcia-Barriocanal, Javier [Universidad Complutense, Spain; Rivera-Calzada, Alberto [Universidad Complutense, Spain; Cuellar, F. [Universidad Complutense de Madrid, Spain; Leon, Carlos [Universidad Complutense de Madrid, Spain; Thakur, P. [European Synchrotron Radiation Facility (ESRF); Cezar, J. C. [European Synchrotron Radiation Facility (ESRF); Brookes, N. B. [European Synchrotron Radiation Facility (ESRF); Garcia-Hernandez, M [Instituto de Ciencia de Materiales de Madrid (ICMM); Dagotto, Elbio R [ORNL; Pennycook, Stephen J [ORNL; Santamaria, J. [Universidad Complutense, Spain

2013-01-01T23:59:59.000Z

354

Atomistic Simulation of Graphene-Polyurethane Nanocomposite for Use in Ballistic Applications  

E-Print Network (OSTI)

Exposure to high impact velocity is the principle limiting factor of material performance in ballistic applications for use in civilian and defense industries. Graphene has emerged as a material of scientific interest due to its exceptional mechanical and thermal properties. When incorporated appropriately in a polymer matrix, graphene can significantly improve properties of polymers at small loading, while preserving the integrity of the polymer. Graphene based polymer nanocomposites provide a novel approach for material design for ballistic applications. The reliability of graphene/polymer nanocomposites on end use applications depends on understanding the effect of structure-property relationship of nanocomposite. A first approach to engineering nanocomposite for ballistic applications requires thorough understanding of physical properties change with incorporation of nanofillers in polymer matrix. One significant class of properties tremendously affected by inclusion of nanofiller is thermodynamic properties. Therefore, a first investigative study, we explore non-linear elastic behavior of graphene using first principle method, specifically Density-Functional Theory (DFT), and atomistic simulation. Using DFT, we calculated the equation of state (EOS) and elastic constants of graphene. The results are in agreement with experimental and other theoretical studies using DFT. However, accuracy of atomistic simulations is limited by empirical potentials. Nevertheless, general anisotropic, non-linear mechanical behavior of graphene is evident on both approaches. Additionally we use molecular dynamics (MD) simulations to study effect of graphene nanofiller on thermo?mechanical properties of polyurethane. We have calculated thermodynamic, structural and mechanical properties of the amorphous polyurethane and its graphene nanocomposite. Our results show significant enhancement of thermal-mechanical properties. The final part of this dissertation, we used non-equilibrium molecular dynamics (NEMD) simulations to investigate dynamic response behavior of polyurethane and its graphene nanocomposite. Calculation of Hugoniot states of polyurethane agrees with experimental studies. However, a phase change phenomenon observed in experimental work was not visible in the present work. This is due to bond breaking and formation, which is a clear characterization of phase changes. Graphene-polyurethane nanocomposites demonstrate similar shock wave propagation illustrating characteristics of impeding shock wave when subjected to different particle velocities. This is due to graphene inducing stress concentrations in the composite, which may increase yield strength.

Njoroge, Jean L

2013-08-01T23:59:59.000Z

355

Transport in the spatially tempered, fractional Fokker-Planck equation  

SciTech Connect

A study of truncated Levy flights in super-diffusive transport in the presence of an external potential is presented. The study is based on the spatially tempered, fractional Fokker-Planck (TFFP) equation in which the fractional diffusion operator is replaced by a tempered fractional diffusion (TFD) operator. We focus on harmonic (quadratic) potentials and periodic potentials with broken spatial symmetry. The main objective is to study the dependence of the steady-state probability density function (PDF), and the current (in the case of periodic potentials) on the level of tempering, lambda, and on the order of the fractional derivative in space, alpha. An expansion of the TFD operator for large lambda is presented, and the corresponding equation for the coarse grained PDF is obtained. The steady-state PDF solution of the TFFP equation for a harmonic potential is computed numerically. In the limit lambda -> infinity, the PDF approaches the expected Boltzmann distribution. However, nontrivial departures from this distribution are observed for finite (lambda > 0) truncations, and alpha not equal 2. In the study of periodic potentials, we use two complementary numerical methods: a finite-difference scheme based on the Grunwald-Letnikov discretization of the truncated fractional derivatives and a Fourier-based spectral method. In the limit lambda -> infinity, the PDFs converges to the Boltzmann distribution and the current vanishes. However, for alpha not equal 2, the PDF deviates from the Boltzmann distribution and a finite non-equilibrium ratchet current appears for any lambda > 0. The current is observed to converge exponentially in time to the steady-state value. The steady-state current exhibits algebraical decay with lambda, as J similar to lambda(-zeta), for alpha >= 1.75. However, for alpha <= 1.5, the steady-state current decays exponentially with lambda, as J similar to e(-xi lambda). In the presence of an asymmetry in the TFD operator, the tempering can lead to a current reversal. A detailed numerical study is presented on the dependence of the current on lambda and the physical parameters of the system.

Kullberg, A. [University of California, Los Angeles; Del-Castillo-Negrete, Diego B [ORNL

2012-01-01T23:59:59.000Z

356

DEGRADATION ISSUES IN SOLID OXIDE CELLS DURING HIGH TEMPERATURE ELECTROLYSIS  

DOE Green Energy (OSTI)

Idaho National Laboratory (INL) is performing high-temperature electrolysis research to generate hydrogen using solid oxide electrolysis cells (SOECs). The project goals are to address the technical and degradation issues associated with the SOECs. This paper provides a summary of various ongoing INL and INL sponsored activities aimed at addressing SOEC degradation. These activities include stack testing, post-test examination, degradation modeling, and a list of issues that need to be addressed in future. Major degradation issues relating to solid oxide fuel cells (SOFC) are relatively better understood than those for SOECs. Some of the degradation mechanisms in SOFCs include contact problems between adjacent cell components, microstructural deterioration (coarsening) of the porous electrodes, and blocking of the reaction sites within the electrodes. Contact problems include delamination of an electrode from the electrolyte, growth of a poorly (electronically) conducting oxide layer between the metallic interconnect plates and the electrodes, and lack of contact between the interconnect and the electrode. INL's test results on high temperature electrolysis (HTE) using solid oxide cells do not provide a clear evidence whether different events lead to similar or drastically different electrochemical degradation mechanisms. Post-test examination of the solid oxide electrolysis cells showed that the hydrogen electrode and interconnect get partially oxidized and become non-conductive. This is most likely caused by the hydrogen stream composition and flow rate during cool down. The oxygen electrode side of the stacks seemed to be responsible for the observed degradation due to large areas of electrode delamination. Based on the oxygen electrode appearance, the degradation of these stacks was largely controlled by the oxygen electrode delamination rate. University of Utah (Virkar) has developed a SOEC model based on concepts in local thermodynamic equilibrium in systems otherwise in global thermodynamic non-equilibrium. This model is under continued development. It shows that electronic conduction through the electrolyte, however small, must be taken into account for determining local oxygen chemical potential, within the electrolyte. The chemical potential within the electrolyte may lie out of bounds in relation to values at the electrodes in the electrolyzer mode. Under certain conditions, high pressures can develop in the electrolyte just under the oxygen electrode (anode)/electrolyte interface, leading to electrode delamination. This theory is being further refined and tested by introducing some electronic conduction in the electrolyte.

M. S. Sohal; J. E. O'Brien; C. M. Stoots; V. I. Sharma; B. Yildiz; A. Virkar

2012-02-01T23:59:59.000Z

357

PHENIX EXPERIMENT AT RHIC: DECADAL PLAN 2004-2013  

Science Conference Proceedings (OSTI)

The PHENIX Collaboration has developed a plan for the detailed investigation of quantum chromodynamics in the next decade. The demonstrated capabilities of the PHENIX experiment to measure rare processes in hadronic, leptonic and photonic channels, in combination with RHIC's unparalleled flexibility as a hadronic collider, provides a physics program of extraordinary breadth and depth. A superlative set of measurements to elucidate the states of both hot and cold nuclear matter, and to measure the spin structure of the proton has been identified. The components of this plan include: (1) Definitive measurements that will establish the nature of the matter created in nucleus+nucleus collisions, that will determine if the description of such matter as a quark-gluon plasma is appropriate, and that will quantify both the equilibrium and non-equilibrium features of the produced medium. (2) Precision measurements of the gluon structure of the proton, and of the spin structure of the gluon and sea-quark distributions of the proton via polarized proton+proton collisions. (3) Determination of the gluon distribution in cold nuclear matter using proton+nucleus collisions. Each of these fundamental fields of investigation will be addressed through a program of correlated measurements in some or all of the following channels: (1) Particle production at high transverse momentum, studied via single particle inclusive measurements of identified charged and neutral hadrons, multi-particle correlations and jet production. (2) Direct photon, photon+jet and virtual photon production. (3) Light and heavy vector mesons. (4) Heavy flavor production. These measurements, together with the established PHENIX abilities to identify hadrons at low transverse momentum, to perform detailed centrality selections, and to monitor polarization and luminosity with high precision create a superb opportunity for performing world-class science with PHENIX for the next decade. A portion of this program is achievable using the present capabilities of PHENIX experimental apparatus, but the physics reach is considerably extended and the program made even more compelling by a proposed set of upgrades which include: (1) An aerogel and time-of-flight system to provide complete {pi}/K/p separation for momenta up to 10 GeV/c. (2) A vertex detector to detect displaced vertices from the decay of mesons containing charm or bottom quarks. (3) A hadron-blind detector to detect and track electrons near the vertex. (4) A micro-TPC to extend the range of PHENIX tracking in azimuth and pseudo-rapidity. (5) A forward detector upgrade for an improved muon trigger to preserve sensitivity at the highest projected RHIC luminosities. (6) A forward calorimeter to provide photon+jet studies over a wide kinematic range. The success of the proposed program is contingent upon several factors external to PHENIX. Implementation of the upgrades is predicated on the availability of R&D funds to develop the required detector technologies on a timely, and in some cases urgent, basis. The necessity for such funding, and the physics merit of the proposed PHENIX program, has been endorsed in the first meeting of BNL's Detector Advisory Committee in December, 2002. Progress towards the physics goals depends in an essential way on the development of the design values for RHIC luminosity, polarization and availability. An analysis based on the guidance from the Collider Accelerator Department indicates that moderate increases in the yearly running time lead to very considerable increases in progress toward the enunciated goals. Efficient access to the rarest probes in the proposed program is achieved via the order-of-magnitude increase in luminosity provided by RHIC-II.

ZAJC,W.ET. AL.

2003-11-30T23:59:59.000Z

358

Computational Analysis of Thermo-Fluidic Characteristics of a Carbon Nano-Fin  

E-Print Network (OSTI)

Miniaturization of electronic devices for enhancing their performance is associated with higher heat fluxes and cooling requirements. Surface modifi cation by texturing or coating is the most cost-effective approach to enhance the cooling of electronic devices. Experiments on carbon nanotube coated heater surfaces have shown heat transfer enhancement of 60 percent. In addition, silicon nanotubes etched on the silicon substrates have shown heat flux enhancement by as much as 120 percent. The heat flux augmentation is attributed to the combined effects of increase in the surface area due to the protruding nanotubes (nano- n eff ect), disruption of vapor lms and modi fication of the thermal/mass di ffusion boundary layers. Since the e ffects of disruption of vapor lms and modifi cation of the thermal/mass di ffusion boundary layers are similar in the above experiments, the difference in enhancement in heat transfer is the consequence of dissimilar nano- n eff ect. The thermal conductivity of carbon nanotubes is of the order of 6000 W/mK while that of silicon is 150 W/mK. However, in the experiments, carbon nanotubes have shown poor performance compared to silicon. This is the consequence of interfacial thermal resistance between the carbon nanotubes and the surrounding fluid since earlier studies have shown that there is comparatively smaller interface resistance to the heat flow from the silicon surface to the surrounding liquids. At the molecular level, atomic interactions of the coolant molecules with the solid substrate as well as their thermal-physical-chemical properties can play a vital role in the heat transfer from the nanotubes. Characterization of the e ffect of the molecular scale chemistry and structure can help to simulate the performance of a nano fin in diff erent kinds of coolants. So in this work to elucidate the eff ect of the molecular composition and structures on the interfacial thermal resistance, water, ethyl alcohol, 1-hexene, n-heptane and its isomers and chains are considered. Non equilibrium molecular dynamic simulations have been performed to compute the interfacial thermal resistance between the carbon nanotube and different coolants as well as to study the diff erent modes of heat transfer. The approach used in these simulations is based on the lumped capacitance method. This method is applicable due to the very high thermal conductivity of the carbon nanotubes, leading to orders of magnitude smaller temperature gradients within the nanotube than between the nanotube and the coolants. To perform the simulations, a single wall carbon nanotube (nano-fin) is placed at the center of the simulation domain surrounded by fluid molecules. The system is minimized and equilibrated to a certain reference temperature. Subsequently, the temperature of the nanotube is raised and the system is allowed to relax under constant energy. The heat transfer from the nano- fin to the surrounding fluid molecules is calculated as a function of time. The temperature decay rate of the nanotube is used to estimate the relaxation time constant and hence the e ffective thermal interfacial resistance between the nano-fi n and the fluid molecules. From the results it can be concluded that the interfacial thermal resistance depends upon the chemical composition, molecular structure, size of the polymer chains and the composition of their mixtures. By calculating the vibration spectra of the molecules of the fluids, it was observed that the heat transfer from the nanotube to the surrounding fluid occurs mutually via the coupling of the low frequency vibration modes.

Singh, Navdeep

2010-12-01T23:59:59.000Z

359

A NOVEL MEMBRANE REACTOR FOR DIRECT HYDROGEN PRODUCTION FROM COAL  

DOE Green Energy (OSTI)

Gas Technology Institute is developing a novel concept of membrane gasifier for high efficiency, clean and low cost production of hydrogen from coal. The concept incorporates a hydrogen-selective membrane within a gasification reactor for direct extraction of hydrogen from coal-derived synthesis gases. The objective of this project is to determine the technical and economic feasibility of this concept by screening, testing and identifying potential candidate membranes under high temperature, high pressure, and harsh environments of the coal gasification conditions. The best performing membranes will be selected for preliminary reactor design and cost estimates. To evaluate the performances of the candidate membranes under the gasification conditions, a high temperature/high pressure hydrogen permeation unit has been constructed in this project. The unit is designed to operate at temperatures up to 1100 C and pressures to 60 atm for evaluation of ceramic membranes such as mixed ionic conducting membrane. The unit was fully commissioned and is operational. Several perovskite membranes based on the formulations of BCN (BaCe{sub 0.8}Nd{sub 0.2}O{sub 3-x}) and BCY (BaCe{sub 0.8}Y{sub 0.2}O{sub 3-x}) were prepared by GTI and tested in the new permeation unit. These membranes were fabricated by either uniaxial pressing or tape casting technique with thickness ranging from 0.2 mm to 0.7 mm. Hydrogen permeation data for the BCN perovskite membrane have been successfully obtained for temperatures between 800 and 950 C and pressures from 1 to 12 bar. The highest hydrogen flux was measured at 1.6 STPcc/min/cm{sup 2} at a hydrogen feed pressure of 12 bar and 950 C with a membrane thickness of 0.22 mm. A membrane gasification reactor model was developed to consider the H{sub 2} permeability of the membrane, the kinetics and the equilibriums of the gas phase reactions in the gasifier, the operating conditions and the configurations of the membrane reactor. The results show that the hydrogen production efficiency using the novel membrane gasification reactor concept can be increased by about 50% versus the conventional gasification process. This confirms the previous evaluation results from the thermodynamic equilibrium calculation. A rigorous model for hydrogen permeation through mixed proton-electron conducting ceramic membranes was also developed based on non-equilibrium thermodynamics. The hydrogen flux predicted from the modeling results are in line with the data from the experimental measurement. The simulation also shows that the presence of steam in the permeate side or the feed side of the membrane can have a small negative effect on the hydrogen flux, in the order of 10%.

Shain Doong; Estela Ong; Mike Atroshenko; Francis Lau; Mike Roberts

2004-10-26T23:59:59.000Z

360

Virtual PCR  

Science Conference Proceedings (OSTI)

The polymerase chain reaction (PCR) stands among the keystone technologies for analysis of biological sequence data. PCR is used to amplify DNA, to generate many copies from as little as a single template. This is essential, for example, in processing forensic DNA samples, pathogen detection in clinical or biothreat surveillance applications, and medical genotyping for diagnosis and treatment of disease. It is used in virtually every laboratory doing molecular, cellular, genetic, ecologic, forensic, or medical research. Despite its ubiquity, we lack the precise predictive capability that would enable detailed optimization of PCR reaction dynamics. In this LDRD, we proposed to develop Virtual PCR (VPCR) software, a computational method to model the kinetic, thermodynamic, and biological processes of PCR reactions. Given a successful completion, these tools will allow us to predict both the sequences and concentrations of all species that are amplified during PCR. The ability to answer the following questions will allow us both to optimize the PCR process and interpret the PCR results: What products are amplified when sequence mixtures are present, containing multiple, closely related targets and multiplexed primers, which may hybridize with sequence mismatches? What are the effects of time, temperature, and DNA concentrations on the concentrations of products? A better understanding of these issues will improve the design and interpretation of PCR reactions. The status of the VPCR project after 1.5 years of funding is consistent with the goals of the overall project which was scoped for 3 years of funding. At half way through the projected timeline of the project we have an early beta version of the VPCR code. We have begun investigating means to improve the robustness of the code, performed preliminary experiments to test the code and begun drafting manuscripts for publication. Although an experimental protocol for testing the code was developed, the preliminary experiments were tainted by contaminated products received from the manufacturer. Much knowledge has been gained in the development of the code thus far, but without final debugging, increasing its robustness and verifying it against experimental results, the papers which we have drafted to share our findings still require the final data necessary for publication. The following sections summarize our final progress on VPCR as it stands after 1.5 years of effort on an ambitious project scoped for a 3 year period. We have additional details of the methods than are provided here, but would like to have legal protection in place before releasing them. The result of this project, a suite of programs that predict PCR products as a function of reaction conditions and sequences, will be used to address outstanding questions in pathogen detection and forensics at LLNL. VPCR should enable scientists to optimize PCR protocols in terms of time, temperature, ion concentration, and primer sequences and concentrations, and to estimate products and error rates in advance of performing experiments. Our proposed capabilities are well ahead of all currently available technologies, which do not model non-equilibrium kinetics, polymerase extension, or predict multiple or undesired PCR products. We are currently seeking DHS funding to complete the project, at which time licensing opportunities will be explored, an updated patent application will be prepared, and a publication will be submitted. A provisional and a full patent application have already been filed (1).

Gardner, S N; Clague, D S; Vandersall, J A; Hon, G; Williams, P L

2006-02-23T23:59:59.000Z

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361

CHANDRA AND XMM-NEWTON STUDIES OF THE SUPERNOVA REMNANT G292.2-0.5 ASSOCIATED WITH THE PULSAR J1119-6127  

SciTech Connect

We present the first detailed imaging and spatially resolved spectroscopic study of the Galactic supernova remnant (SNR) G292.2-0.5, associated with the high-magnetic field radio pulsar (PSR) J1119-6127, using Chandra and XMM-Newton. The high-resolution X-ray images reveal a partially limb-brightened morphology in the west, with diffuse emission concentrated toward the interior of the remnant unlike the complete shell-like morphology observed at radio wavelengths. The spectra of most of the diffuse emission regions within the remnant are best described by a two-component thermal+non-thermal model. The thermal component is described by a plane-parallel, non-equilibrium ionization plasma model with a temperature kT ranging from 1.3{sup +0.3}{sub -0.2} keV in the western side of the remnant to 2.3{sup +2.9}{sub -0.5} keV in the east, a column density increasing from 1.0{sup +0.1}{sub -0.6} Multiplication-Sign 10{sup 22} cm{sup -2} in the west to 1.8{sup +0.2}{sub -0.4} Multiplication-Sign 10{sup 22} cm{sup -2} in the east, and a low ionization timescale ranging from (5.7{sup +0.8}{sub -0.7}) Multiplication-Sign 10{sup 9} cm{sup -3} s in the SNR interior to (3.6{sup +0.7}{sub -0.6}) Multiplication-Sign 10{sup 10} cm{sup -3} s in the western side-suggestive of expansion of a young remnant in a low-density medium. The spatial and spectral differences across the SNR are consistent with the presence of a dark cloud in the eastern part of the SNR, absorbing the soft X-ray emission, as also revealed by the optical image of that region. The spectra from some of the regions also show slightly enhanced metal abundances from Ne, Mg, and Si, hinting at the first evidence for ejecta heated by the reverse shock. Comparing our inferred metal abundances to core-collapse nucleosynthesis models yields, we estimate a high progenitor mass of {approx}30 M{sub Sun} suggesting a Type Ib/c supernova. We confirm the presence of non-thermal X-ray emission from regions close to the pulsar, with the emission characterized by a power-law model with a hard photon index similar to that seen in the compact pulsar wind nebula. We estimate an SNR age range between 4.2 kyr (free expansion phase) and 7.1 kyr (Sedov phase) at an assumed distance of 8.4 kpc, a factor of a few higher than the measured pulsar's age upper limit of 1.9 kyr.

Kumar, Harsha S.; Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Gonzalez, Marjorie E., E-mail: harsha@physics.umanitoba.ca, E-mail: samar@physics.umanitoba.ca, E-mail: gonzalez@phas.ubc.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

2012-08-01T23:59:59.000Z

362

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS  

SciTech Connect

We report on progress in three areas. In part one, the wetting effects of synthetic base oils are reported. Part two reports progress in understanding the effects of surfactants of known chemical structures, and part three integrates the results from surface and core tests that show the wetting effects of commercial surfactant products used in synthetic and traditional oil-based drilling fluids. An important difference between synthetic and traditional oil-based muds (SBM and OBM, respectively) is the elimination of aromatics from the base oil to meet environmental regulations. The base oils used include dearomatized mineral oils, linear alpha-olefins, internal olefins, and esters. We show in part one that all of these materials except the esters can, at sufficiently high concentrations, destabilize asphaltenes. The effects of asphaltenes on wetting are in part related to their stability. Although asphaltenes have some tendency to adsorb on solid surfaces from a good solvent, that tendency can be much increased near the onset of asphaltene instability. Tests in Berea sandstone cores demonstrate wetting alteration toward less water-wet conditions that occurs when a crude oil is displaced by paraffinic and olefinic SBM base oils, whereas exposure to the ester products has little effect on wetting properties of the cores. Microscopic observations with atomic forces microscopy (AFM) and macroscopic contact angle measurements have been used in part 2 to explore the effects on wetting of mica surfaces using oil-soluble polyethoxylated amine surfactants with varying hydrocarbon chain lengths and extent of ethoxylation. In the absence of water, only weak adsorption occurs. Much stronger, pH-dependent adsorption was observed when water was present. Varying hydrocarbon chain length had little or no effect on adsorption, whereas varying extent of ethoxylation had a much more significant impact, reducing contact angles at nearly all conditions tested. Preequilibration of aqueous and oleic phases appeared to have little influence over surfactant interactions with the mica surface; the solubility in water of all three structures appeared to be very limited. Commercial emulsifiers for both SBM and OBM formulations are blends of tall oil fatty acids and their polyaminated derivatives. In part three of this report, we integrate observations on smooth surfaces with those in Berea sandstone cores to show the effects of low concentrations of these products with and without the added complexity of adsorbed material from crude oils. Unlike the polyethoxylated amines studied in part two, there are significant non-equilibrium effects that can occur when water first contacts oil with dissolved surfactant. Very oil-wet conditions can be produced on first contact. Surfactant dissolved in oil had less effect on wetting alteration for one combination of crude oil and surfactant, although the generality of this observation can only be assessed by additional tests with crude oils of different composition. The wettability-altering effect of surfactants on both mica and Berea sandstone was most significant when they contacted surfaces after adsorption of crude oil components. Tests without crude oil might underestimate the extent of wetting change possible with these SBM and OBM emulsifiers.

Jill S. Buckley; Norman R. Morrow

2004-05-01T23:59:59.000Z

363

Oxygen Transport Membranes  

SciTech Connect

The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the small polaron conduction mechanism. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to develop strategies to detect and characterize vacancy creation, dopant segregations and defect association in the oxygen conducting membrane material. The pO{sub 2} and temperature dependence of the conductivity, non-stoichiometry and thermal-expansion behavior of compositions with increasing complexity of substitution on the perovskite A and B sites were studied. Studies with the perovskite structure show anomalous behavior at low oxygen partial pressures (<10{sup -5} atm). The anomalies are due to non-equilibrium effects and can be avoided by using very strict criteria for the attainment of equilibrium. The slowness of the oxygen equilibration kinetics arises from two different mechanisms. In the first, a two phase region occurs between an oxygen vacancy ordered phase such as brownmillerite SrFeO{sub 2.5} and perovskite SrFeO{sub 3-x}. The slow kinetics is associated with crossing the two phase region. The width of the miscibility gap decreases with increasing temperature and consequently the effect is less pronounced at higher temperature. The preferred kinetic pathway to reduction of perovskite ferrites when the vacancy concentration corresponds to the formation of significant concentrations of Fe{sup 2+} is via the formation of a Ruddlesden-Popper (RP) phases as clearly observed in the case of La{sub 0.5}Sr{sub 0.5}FeO{sub 3-x} where LaSrFeO{sub 4} is found together with Fe. In more complex compositions, such as LSFTO, iron or iron rich phases are observed locally with no evidence for the presence of discrete RP phase. Fracture strength of tubular perovskite membranes was determined in air and in reducing atmospheric conditions. The strength of the membrane decreased with temperature and severity of reducing conditions although the strength distribution (Weibull parameter, m) was relatively unaltered. Surface and volume dominated the fracture origins and the overall fracture was purely transgranular. The dual phas

S. Bandopadhyay

2008-08-30T23:59:59.000Z

364

Phase 1 Final Technical Report - MgB2 Synthesis for High Field Performance  

Science Conference Proceedings (OSTI)

Accelerator Technology Corp. (ATC) has successfully completed its Phase 1 effort to devel-op rf plasma torch synthesis of MgB2 superconducting powder. The overall objective is to de-velop a way to introduce homogeneous alloying of C and SiC impurities into phase-pure MgB2. Several groups have attained remarkable benefits from such alloying in raising the upper critical field Hc2 from ~14 T to ~30 T (bulk) and ~50 T (thin films). But no one has succeeded in pro-ducing that benefit homogeneously, so that current transport in a practical powder-in-tube (PIT) conductor is largely the same as without the alloying. ATC has conceived the possibility of attaining such homogeneity by passing aerosol suspen-sions of reactant powders through an rf plasma torch, with each reactant transported on a stream-line that heats it to an optimum temperature for the synthesis reaction. This procedure would uniquely access non-equilibrium kinetics for the synthesis reaction, and would provide the possi-bility to separately control the temperature and stoichiometry of each reactant as it enters the mixing region where synthesis occurs. It also facilitates the introduction of seed particles (e.g. nanoscale SiC) to dramatically enhance the rate of the synthesis reaction compared to gas-phase synthesis in rf plasma reported by Canfield and others. During the Phase 1 effort ATC commissioned its 60 kW 5 MHz rf source for a manufactur-ing-scale rf plasma torch. This effort required repair of numerous elements, integration of cooling and input circuits, and tuning of the load characteristics. The effort was successful, and the source has now been tested to ~full power. Also in the Phase 1 effort we encountered a subsidiary but very important problem: the world is running out of the only present supply of phase-pure amorphous boron. The starting boron powder must be in the amorphous phase in order for the synthesis reaction to produce phase-pure MgB2. Even small contamination with crystalline boron results in the formation of parasitic phases such as MgB4, MgB7, etc. Such parasitic phases are a primary element of the connectivity problem, in which even though a sample powder may contain grains of high-quality MgB2, adjacent grains are surrounded by intergrowths of parasitic phases so that current trans-port is badly degraded. The best results to date have been obtained using boron powder produced long ago for a rocket propellant development project. The synthesis process was complex and is now largely lost, and the manufacturing equipment has long since been scrapped. The last batch of the powder has been used during recent years to support MgB2 R&D at several labs, but supplies are dwindling. ATC has identified a first application of its plasma torch to synthesize phase-pure amorphous boron flake using a rapid-quench splat technique. Inexpensive technical-grade boron would be purified of contaminants, then dispersed as an aerosol in inert gas and passed through the plasma torch to melt it into a spray. The spray would be splat-condensed on a rotating drum to form pure amorphous flake. The process would begin with technical-grade boron powder, having good stoichiometric purity, nanoscale particles, but significant contamination of MgO and crystalline boron. We used wet chemistry to remove B2O3 completely and reduced the MgO impurity, and analyzed the particle size distribution using a Coulter counter and the phase composition using X-ray diffrac-tion (XRD). The next step will be to build an rf plasma torch with a recirculating single-component aerosol feed and the cooled splat drum and collector, and undertake process devel-opment for amorphous boron powder. This revised goal has two benefits. First, it is an easier technology than our ultimate goal of a multi-component laminar flow torch. We have been counseled by those experienced in plasma torch technology that our ultimate goal will require a torch that should be feasible but has never been attempted. It may require an extended period of R&D for both the torch itself and the gas dynamics in the rea

Mohit Bhatia; Peter McIntyre

2009-11-02T23:59:59.000Z