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Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach

We consider nonequilibrium (NEQ) states such as supercooled liquids and glasses that are described with the use of internal variables. We classify the latter by the state-dependent hierarchy of relaxation times to assess their relevance for irreversible contributions. Given an observation time [Form...

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Autor principal: Gujrati, Purushottam D.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512666/
https://www.ncbi.nlm.nih.gov/pubmed/33265240
http://dx.doi.org/10.3390/e20030149
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author Gujrati, Purushottam D.
author_facet Gujrati, Purushottam D.
author_sort Gujrati, Purushottam D.
collection PubMed
description We consider nonequilibrium (NEQ) states such as supercooled liquids and glasses that are described with the use of internal variables. We classify the latter by the state-dependent hierarchy of relaxation times to assess their relevance for irreversible contributions. Given an observation time [Formula: see text] , we determine the window of relaxation times that divide the internal variables into active and inactive groups, the former playing a central role in the NEQ thermodynamics. Using this thermodynamics, we determine (i) a bound on the NEQ entropy and on the residual entropy and (ii) the nature of the isothermal relaxation of the entropy and the enthalpy in accordance with the second law. A theory that violates the second law such as the entropy loss view is shown to be internally inconsistent if we require it to be consistent with experiments. The inactive internal variables still play an indirect role in determining the temperature [Formula: see text] and the pressure [Formula: see text] of the system, which deviate from their external values.
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spelling pubmed-75126662020-11-09 Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach Gujrati, Purushottam D. Entropy (Basel) Article We consider nonequilibrium (NEQ) states such as supercooled liquids and glasses that are described with the use of internal variables. We classify the latter by the state-dependent hierarchy of relaxation times to assess their relevance for irreversible contributions. Given an observation time [Formula: see text] , we determine the window of relaxation times that divide the internal variables into active and inactive groups, the former playing a central role in the NEQ thermodynamics. Using this thermodynamics, we determine (i) a bound on the NEQ entropy and on the residual entropy and (ii) the nature of the isothermal relaxation of the entropy and the enthalpy in accordance with the second law. A theory that violates the second law such as the entropy loss view is shown to be internally inconsistent if we require it to be consistent with experiments. The inactive internal variables still play an indirect role in determining the temperature [Formula: see text] and the pressure [Formula: see text] of the system, which deviate from their external values. MDPI 2018-02-26 /pmc/articles/PMC7512666/ /pubmed/33265240 http://dx.doi.org/10.3390/e20030149 Text en © 2018 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Gujrati, Purushottam D.
Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title_full Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title_fullStr Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title_full_unstemmed Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title_short Hierarchy of Relaxation Times and Residual Entropy: A Nonequilibrium Approach
title_sort hierarchy of relaxation times and residual entropy: a nonequilibrium approach
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7512666/
https://www.ncbi.nlm.nih.gov/pubmed/33265240
http://dx.doi.org/10.3390/e20030149
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