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1
Pekař, Miloslav. « Thermodynamics and foundations of mass-action kinetics ». Progress in Reaction Kinetics and Mechanism 30, no 1-2 (juin 2005) : 3–113. http://dx.doi.org/10.3184/007967405777874868.
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A critical overview is given of phenomenological thermodynamic approaches to reaction rate equations of the type based on the law of mass-action. The review covers treatments based on classical equilibrium and irreversible (linear) thermodynamics, extended irreversible, rational and continuum thermodynamics. Special attention is devoted to affinity, the applications of activities in chemical kinetics and the importance of chemical potential. The review shows that chemical kinetics survives as the touchstone of these various thermody-namic theories. The traditional mass-action law is neither demonstrated nor proved and very often is only introduced post hoc into the framework of a particular thermodynamic theory, except for the case of rational thermodynamics. Most published “thermodynamic'’ kinetic equations are too complicated to find application in practical kinetics and have merely theoretical value. Solely rational thermodynamics can provide, in the specific case of a fluid reacting mixture, tractable rate equations which directly propose a possible reaction mechanism consistent with mass conservation and thermodynamics. It further shows that affinity alone cannot determine the reaction rate and should be supplemented by a quantity provisionally called constitutive affinity. Future research should focus on reaction rates in non-isotropic or non-homogeneous mixtures, the applicability of traditional (equilibrium) expressions relating chemical potential to activity in non-equilibrium states, and on using activities and activity coefficients determined under equilibrium in non-equilibrium states.
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Michaelian, Karo. « Non-Equilibrium Thermodynamic Foundations of the Origin of Life ». Foundations 2, no 1 (21 mars 2022) : 308–37. http://dx.doi.org/10.3390/foundations2010022.
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There is little doubt that life’s origin followed from the known physical and chemical laws of Nature. The most general scientific framework incorporating the laws of Nature and applicable to most known processes to good approximation, is that of thermodynamics and its extensions to treat out-of-equilibrium phenomena. The event of the origin of life should therefore also be amenable to such an analysis. In this review paper, I describe the non-equilibrium thermodynamic foundations of the origin of life for the non-expert from the perspective of the “Thermodynamic Dissipation Theory for the Origin of Life” which is founded on Classical Irreversible Thermodynamic theory developed by Lars Onsager, Ilya Prigogine, and coworkers. A Glossary of Thermodynamic Terms can be found at the end of the article to aid the reader.
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Tangde, Vijay M., et Anil A. Bhalekar. « How Flexible Is the Concept of Local Thermodynamic Equilibrium ? » Entropy 25, no 1 (10 janvier 2023) : 145. http://dx.doi.org/10.3390/e25010145.
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It has been demonstrated by using generalized phenomenological irreversible thermodynamic theory (GPITT) that by replacing the conventional composition variables {xk} by the quantum level composition variables {x˜k,j} corresponding to the nonequilibrium population of the quantum states, the resultant description remains well within the local thermodynamic equilibrium (LTE) domain. The next attempt is to replace the quantum level composition variables by their respective macroscopic manifestations as variables. For example, these manifestations are, say, the observance of fluorescence and phosphorescence, existence of physical fluxes, and ability to register various spectra (microwave, IR, UV-VIS, ESR, NMR, etc.). This exercise results in a framework that resembles with the thermodynamics with internal variables (TIV), which too is obtained as a framework within the LTE domain. This TIV-type framework is easily transformed to an extended irreversible thermodynamics (EIT) type framework, which uses physical fluxes as additional variables. The GPITT in EIT version is also obtained well within the LTE domain. Thus, GPITT becomes a complete version of classical irreversible thermodynamics (CIT). It is demonstrated that LTE is much more flexible than what CIT impresses upon. This conclusion is based on the realization that the spatial uniformity for each tiny pocket (cell) of a spatially non-uniform system remains intact while developing GPITT and obviously in its other versions.
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Bryant, Samuel J., et Benjamin B. Machta. « Energy dissipation bounds for autonomous thermodynamic cycles ». Proceedings of the National Academy of Sciences 117, no 7 (4 février 2020) : 3478–83. http://dx.doi.org/10.1073/pnas.1915676117.
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How much free energy is irreversibly lost during a thermodynamic process? For deterministic protocols, lower bounds on energy dissipation arise from the thermodynamic friction associated with pushing a system out of equilibrium in finite time. Recent work has also bounded the cost of precisely moving a single degree of freedom. Using stochastic thermodynamics, we compute the total energy cost of an autonomously controlled system by considering both thermodynamic friction and the entropic cost of precisely directing a single control parameter. Our result suggests a challenge to the usual understanding of the adiabatic limit: Here, even infinitely slow protocols are energetically irreversible.
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Abourabia, A. M., et T. Z. Abdel Wahid. « The unsteady Boltzmann kinetic equation and non-equilibrium thermodynamics of an electron gas for the Rayleigh flow problem ». Canadian Journal of Physics 88, no 7 (juillet 2010) : 501–11. http://dx.doi.org/10.1139/p10-032.
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In the framework of irreversible thermodynamics, the characteristics of the Rayleigh flow problem of a rarified electron gas extracted from neutral atoms is examined and proved to obey the entropic behavior for gas systems. A model kinetic equation of the BGK (Bhatnager–Gross–Krook) type is solved, using the method of moments with a two-sided distribution function. Various macroscopic properties of the electron gas, such as the mean velocity, the shear stress, and the viscosity coefficient, together with the induced electric and magnetic fields, are investigated with respect to both distance and time. The distinction between the perturbed velocity distribution functions and the equilibrium velocity distribution function at different time values is illustrated. We restrict our study to the domain of irreversible thermodynamics processes with small deviation from the equilibrium state to estimate the entropy, entropy production, entropy flux, thermodynamic force, and kinetic coefficient and verify the celebrated Boltzmann H-theorem for non-equilibrium thermodynamic properties of the system. The ratios between the different contributions of the internal energy changes, based upon the total derivatives of the extensive parameters, are predicted via Gibbs’ equation for both diamagnetic and paramagnetic plasmas. The results are applied to a typical model of laboratory argon plasma.
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Ganghoffer, Jean-François, et Rachid Rahouadj. « Thermodynamic formulations of continuum growth of solid bodies ». Mathematics and Mechanics of Solids 22, no 5 (10 décembre 2015) : 1027–46. http://dx.doi.org/10.1177/1081286515616228.
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The thermodynamics of open systems exchanging mass, heat, energy, and entropy with their environment is examined as a convenient unifying framework to describe the evolution of growing solid bodies in the context of volumetric growth. Following the theory of non-equilibrium thermodynamics (NET) introduced by De Donder and followers from the Brussels School of Thermodynamics, the formulation of the NET of irreversible processes for multicomponent solid bodies is shortly reviewed. In the second part, extending the framework of NET to open thermodynamic systems, the balance laws for continuum solid bodies undergoing growth phenomena incorporating mass sources and mass fluxes are expressed, leading to a formulation of the second principle highlighting the duality between irreversible fluxes and conjugated driving forces. A connection between NET and the open system thermodynamic formulation for growing continuum solid bodies is obtained by interpreting the balance laws with source terms as contributions from an external reservoir of nutrients.
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Öttinger, Hans Christian. « GENERIC Integrators : Structure Preserving Time Integration for Thermodynamic Systems ». Journal of Non-Equilibrium Thermodynamics 43, no 2 (25 avril 2018) : 89–100. http://dx.doi.org/10.1515/jnet-2017-0034.
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AbstractThermodynamically admissible evolution equations for non-equilibrium systems are known to possess a distinct mathematical structure. Within the GENERIC (general equation for the non-equilibrium reversible–irreversible coupling) framework of non-equilibrium thermodynamics, which is based on continuous time evolution, we investigate the possibility of preserving all the structural elements in time-discretized equations. Our approach, which follows Moser’s [1] construction of symplectic integrators for Hamiltonian systems, is illustrated for the damped harmonic oscillator. Alternative approaches are sketched.
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Dewey, T. Gregory. « Algorithmic Complexity and Thermodynamics of Fractal Growth Processes ». Fractals 05, no 04 (décembre 1997) : 697–706. http://dx.doi.org/10.1142/s0218348x97000565.
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A statistical mechanical formalism is developed using the computer information concepts of algorithmic complexity and Kolmogorov universal probability. This formalism provides a thermodynamic description of microstates of a system. For an isolated classical system, the algorithmic complexity is equal to the thermodynamic entropy. This approach does not rely on probabilistic ensemble concepts and can be applied to non-ergodic systems. An H-function is developed from the Kolmogorov universal probability that satisfies the properties of an entropy function. Using this approach, the thermodynamics of irreversible growth processes far from equilibrium can be investigated. Entropy functions for fractal growth processes far from equilibrium are developed from the algorithmic complexity and are seen to be similar to Flory-type equilibrium functions. This development does not require energy minimization procedures associated with equilibrium arguments. Using this approach, constraints can be put on the types of mean field models that will yield fractal structures. The algorithmic complexity of a system can also be used to explore the role of fluctuations and criticality in highly ordered systems.
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GAO, TIANFU, et JINCAN CHEN. « NON-EQUILIBRIUM THERMODYNAMIC ANALYSIS ON THE PERFORMANCE OF AN IRREVERSIBLE THERMALLY DRIVEN BROWNIAN MOTOR ». Modern Physics Letters B 24, no 03 (30 janvier 2010) : 325–33. http://dx.doi.org/10.1142/s0217984910022408.
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Based on the general model of thermally-driven Brownian motors, an equivalent cycle system is established and the Onsager coefficients and efficiency at the maximum power output of the system are analytically calculated from non-equilibrium thermodynamics. It is found that the Onsager reciprocity relation holds and the Onsager coefficients are affected by the main irreversibilities existing in practical systems. Only when the heat leak and the kinetic energy change of the particle in the system are negligible, can the determinant of the Onsager matrix vanish. It is also found that in the frame of non-equilibrium thermodynamics, the power output and efficiency of an irreversible Brownian motor can be expressed to be the same form as those of an irreversible Carnot heat engine, so the results obtained here are of general significance. Moreover, these results are used to analyze the performance characteristics of a class of thermally-driven Brownian motors so that some important conclusions in literature may be directly derived from the present paper.
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Mendoza, D. F., et S. Kjelstrup. « Modeling a non-equilibrium distillation stage using irreversible thermodynamics ». Chemical Engineering Science 66, no 12 (juin 2011) : 2713–22. http://dx.doi.org/10.1016/j.ces.2011.03.023.
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Michaelian, Karo. « The Dissipative Photochemical Origin of Life : UVC Abiogenesis of Adenine ». Entropy 23, no 2 (10 février 2021) : 217. http://dx.doi.org/10.3390/e23020217.
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The non-equilibrium thermodynamics and the photochemical reaction mechanisms are described which may have been involved in the dissipative structuring, proliferation and complexation of the fundamental molecules of life from simpler and more common precursors under the UVC photon flux prevalent at the Earth’s surface at the origin of life. Dissipative structuring of the fundamental molecules is evidenced by their strong and broad wavelength absorption bands in the UVC and rapid radiationless deexcitation. Proliferation arises from the auto- and cross-catalytic nature of the intermediate products. Inherent non-linearity gives rise to numerous stationary states permitting the system to evolve, on amplification of a fluctuation, towards concentration profiles providing generally greater photon dissipation through a thermodynamic selection of dissipative efficacy. An example is given of photochemical dissipative abiogenesis of adenine from the precursor HCN in water solvent within a fatty acid vesicle floating on a hot ocean surface and driven far from equilibrium by the incident UVC light. The kinetic equations for the photochemical reactions with diffusion are resolved under different environmental conditions and the results analyzed within the framework of non-linear Classical Irreversible Thermodynamic theory.
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Szücs, Mátyás, Róbert Kovács et Srboljub Simić. « Open Mathematical Aspects of Continuum Thermodynamics : Hyperbolicity, Boundaries and Nonlinearities ». Symmetry 12, no 9 (7 septembre 2020) : 1469. http://dx.doi.org/10.3390/sym12091469.
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Thermodynamics is continuously spreading in the engineering practice, which is especially true for non-equilibrium models in continuum problems. Although there are concepts and approaches beyond the classical knowledge, which are known for decades, their mathematical properties, and consequences of the generalizations are less-known and are still of high interest in current researches. Therefore, we found it essential to collect the most important and still open mathematical questions that are related to different continuum thermodynamic approaches. First, we start with the example of Classical Irreversible Thermodynamics (CIT) in order to provide the basis for the more general and complex frameworks, such as the Non-Equilibrium Thermodynamics with Internal Variables (NET-IV) and Rational Extended Thermodynamics (RET). Here, we aim to present that each approach has its specific problems, such as how the initial and boundary conditions can be formulated, how the coefficients in the partial differential equations are connected to each other, and how it affects the appearance of nonlinearities. We present these properties and comparing the approach of NET-IV and RET to each other from these points of view. In the present work, we restrict ourselves on non-relativistic models.
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Esen, Oğul, Miroslav Grmela et Michal Pavelka. « On the role of geometry in statistical mechanics and thermodynamics. II. Thermodynamic perspective ». Journal of Mathematical Physics 63, no 12 (1 décembre 2022) : 123305. http://dx.doi.org/10.1063/5.0099930.
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The General Equation for Non-Equilibrium Reversible–Irreversible Coupling (GENERIC) provides the structure of mesoscopic multiscale dynamics that guarantees the emergence of equilibrium states. Similarly, a lift of the GENERIC structure to iterated cotangent bundles, called a rate GENERIC, guarantees the emergence of the vector fields that generate the approach to equilibrium. Moreover, the rate GENERIC structure also extends Onsager’s variational principle. The maximum entropy principle in the GENERIC structure becomes the Onsager variational principle in the rate GENERIC structure. In the absence of external forces, the rate entropy is a potential that is closely related to the entropy production. In the presence of external forces when the entropy does not exist, the rate entropy still exists. While the entropy at the conclusion of the GENERIC time evolution gives rise to equilibrium thermodynamics, the rate entropy at the conclusion of the rate GENERIC time evolution gives rise to rate thermodynamics. Both GENERIC and rate GENERIC structures are put into the geometrical framework in the first paper of this series. The rate GENERIC is also shown to be related to Grad’s hierarchy analysis of reductions of the Boltzmann equation. Chemical kinetics and kinetic theory provide illustrative examples. We introduce rate GENERIC extensions (and thus also Onsager-variational-principle formulations) of both chemical kinetics and the Boltzmann kinetic theory.
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Israelachvili, Jacob. « Differences between non-specific and bio-specific, and between equilibrium and non-equilibrium, interactions in biological systems ». Quarterly Reviews of Biophysics 38, no 4 (novembre 2005) : 331–37. http://dx.doi.org/10.1017/s0033583506004203.
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Biological interactions are ‘processes’ 331Intermolecular forces involved 332Synergy between different forces occurring at different locations 333Non-equilibrium, rate and time-dependent interactions 335Reversible and irreversible interactions 337The interaction forces between biological molecules and surfaces are much more complex than those between non-biological molecules or surfaces, such as colloidal particle surfaces. This complexity is due to a number of factors: (i) the simultaneous involvement of many different molecules and different non-covalent forces – van der Waals, electrostatic, solvation (hydration, hydrophobic), steric, entropic and ‘specific’, and (ii) the flexibility of biological macromolecules and fluidity of membranes. Biological interactions are better thought of as ‘processes’ that evolve in space and time and, under physiological conditions, involve a continuous input of energy. Such systems are, therefore, not at thermodynamic equilibrium, or even tending towards equilibrium. Recent surface forces apparatus (SFA) and atomic force microscopy (AFM) measurements on supported model membrane systems (protein-containing lipid bilayers) illustrate these effects. It is suggested that the major theoretical challenge is to establish manageable theories or models that can describe the spatial and time evolution of systems consisting of different molecules subject to certain starting conditions or energy inputs.
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Serdyukov, Sergey. « Macroscopic Entropy of Non-Equilibrium Systems and Postulates of Extended Thermodynamics : Application to Transport Phenomena and Chemical Reactions in Nanoparticles ». Entropy 20, no 10 (18 octobre 2018) : 802. http://dx.doi.org/10.3390/e20100802.
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In this work, we consider extended irreversible thermodynamics in assuming that the entropy density is a function of both common thermodynamic variables and their higher-order time derivatives. An expression for entropy production, and the linear phenomenological equations describing diffusion and chemical reactions, are found in the context of this approach. Solutions of the sets of linear equations with respect to fluxes and their higher-order time derivatives allow the coefficients of diffusion and reaction rate constants to be established as functions of size of the nanosystems in which these reactions occur. The Maxwell-Cattaneo and Jeffreys constitutive equations, as well as the higher-order constitutive equations, which describe the processes in reaction-diffusion systems, are obtained.
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Hütter, Markus, et Bob Svendsen. « Thermodynamic model formulation for viscoplastic solids as general equations for non-equilibrium reversible–irreversible coupling ». Continuum Mechanics and Thermodynamics 24, no 3 (17 janvier 2012) : 211–27. http://dx.doi.org/10.1007/s00161-011-0232-7.
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Bartelt, Perry, Othmar Buser et Martin Kern. « Dissipated work, stability and the internal flow structure of granular snow avalanches ». Journal of Glaciology 51, no 172 (2005) : 125–38. http://dx.doi.org/10.3189/172756505781829638.
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AbstractWe derive work dissipation functionals for granular snow avalanches flowing in simple shear. Our intent is to apply constructive theorems of non-equilibrium thermodynamics to the snow avalanche problem. Snow chute experiments show that a bi-layer system consisting of a non-yielded flow plug overriding a sheared fluidized layer can be used to model avalanche flow. We show that for this type of constitutive behaviour the dissipation functionals are minimum at steady state with respect to variations in internal velocity; however, the functionals must be constrained by subsidiary mass- continuity integrals before the equivalence of momentum balance and minimal work dissipation can be established. Constitutive models that do not satisfy this equivalence are henceforth excluded from our consideration. Fluctuations in plug and slip velocity depend on the roughness of the flow surface and viscosity of the granular system. We speculate that this property explains the transition from flowing avalanches to powder avalanches. Because the temperature can safely be assumed constant, we demonstrate within the context of non-equilibrium thermodynamics that granular snow avalanches are irreversible, dissipative systems, minimizing – in space – entropy production. Furthermore, entropy production is linear both near and far from steady-state non-equilibrium because of the mass-continuity constraint. Finally, we derive thermodynamic forces and conjugate fluxes as well as expressing the corresponding phenomenological Onsager coefficients in terms of the constitutive parameters.
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Zivieri, Roberto, et Nicola Pacini. « Entropy Density Acceleration and Minimum Dissipation Principle : Correlation with Heat and Matter Transfer in Glucose Catabolism ». Entropy 20, no 12 (5 décembre 2018) : 929. http://dx.doi.org/10.3390/e20120929.
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The heat and matter transfer during glucose catabolism in living systems and their relation with entropy production are a challenging subject of the classical thermodynamics applied to biology. In this respect, an analogy between mechanics and thermodynamics has been performed via the definition of the entropy density acceleration expressed by the time derivative of the rate of entropy density and related to heat and matter transfer in minimum living systems. Cells are regarded as open thermodynamic systems that exchange heat and matter resulting from irreversible processes with the intercellular environment. Prigogine’s minimum energy dissipation principle is reformulated using the notion of entropy density acceleration applied to glucose catabolism. It is shown that, for out-of-equilibrium states, the calculated entropy density acceleration for a single cell is finite and negative and approaches as a function of time a zero value at global thermodynamic equilibrium for heat and matter transfer independently of the cell type and the metabolic pathway. These results could be important for a deeper understanding of entropy generation and its correlation with heat transfer in cell biology with special regard to glucose catabolism representing the prototype of irreversible reactions and a crucial metabolic pathway in stem cells and cancer stem cells.
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Szücs, Mátyás, et Tamás Fülöp. « Kluitenberg–Verhás Rheology of Solids in the GENERIC Framework ». Journal of Non-Equilibrium Thermodynamics 44, no 3 (26 juillet 2019) : 247–59. http://dx.doi.org/10.1515/jnet-2018-0074.
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Abstract The internal variable methodology of non-equilibrium thermodynamics, with a symmetric tensorial internal variable, provides an important rheological model family for solids, the so-called Kluitenberg–Verhás model family [Cs. Asszonyi et al., Contin. Mech. Thermodyn. 27, 2015]. This model family is distinguished not only by theoretical aspects but also on experimental grounds (see [Cs. Asszonyi et al., Period. Polytech., Civ. Eng. 60, 2016] for plastics and [W. Lin et al., Rock Engineering in Difficult Ground Conditions (Soft Rock and Karst), Proceedings of Eurock’09, 2009; K. Matsuki, K. Takeuchi, Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 30, 1993; K. Matsuki, Int. J. Rock Mech. Min. Sci. 45, 2008] for rocks). In this article, we present and discuss how the internal variable formulation of the Kluitenberg–Verhás model family can be presented in the non-equilibrium thermodynamical framework GENERIC (General Equation for the Non-Equilibrium Reversible–Irreversible Coupling) [H. C. Öttinger, Beyond Equilibrium Thermodynamics, 2005; M. Grmela, J. Non-Newton. Fluid Mech. 165, 2010; M. Grmela, H. C. Öttinger, Phys. Rev. E 56, 1997; H. C. Öttinger, M. Grmela, Phys. Rev. E 56, 1997], for the benefit of both thermodynamical methodologies and promising practical applications.
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Glavatskiy, K. S. « Local equilibrium and the second law of thermodynamics for irreversible systems with thermodynamic inertia ». Journal of Chemical Physics 143, no 16 (28 octobre 2015) : 164101. http://dx.doi.org/10.1063/1.4933431.
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Giannetti, Niccolò, Seiichi Yamaguchi, Andrea Rocchetti et Kiyoshi Saito. « Thermodynamic Analysis of Irreversible Desiccant Systems ». Entropy 20, no 8 (9 août 2018) : 595. http://dx.doi.org/10.3390/e20080595.
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A new general thermodynamic mapping of desiccant systems’ performance is conducted to estimate the potentiality and determine the proper application field of the technology. This targets certain room conditions and given outdoor temperature and humidity prior to the selection of the specific desiccant material and technical details of the system configuration. This allows the choice of the operative state of the system to be independent from the limitations of the specific design and working fluid. An expression of the entropy balance suitable for describing the operability of a desiccant system at steady state is obtained by applying a control volume approach, defining sensible and latent effectiveness parameters, and assuming ideal gas behaviour of the air-vapour mixture. This formulation, together with mass and energy balances, is used to conduct a general screening of the system performance. The theoretical advantage and limitation of desiccant dehumidification air conditioning, maximum efficiency for given conditions constraints, least irreversible configuration for a given operative target, and characteristics of the system for a target efficiency can be obtained from this thermodynamic mapping. Once the thermo-physical properties and the thermodynamic equilibrium relationship of the liquid desiccant mixture or solid coating material are known, this method can be applied to a specific technical case to select the most appropriate working medium and guide the specific system design to achieve the target performance.
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Baur, H. « The Glass Transition Within the Thermodynamics of Irreversible Processes ». Zeitschrift für Naturforschung A 53, no 3-4 (1 avril 1998) : 157–70. http://dx.doi.org/10.1515/zna-1998-3-410.
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Abstract The glass transition caused by a finite cooling rate is a continuous non-linear dissipative process whose description requires a clear distinction between equilibrium and non-equilibrium quantities. The so-called Davies or Prigogine-Defay relations (in form of an equation as well as in form of an inequality) are not relevant in such a process. The determining quantities of the glass transition are -from a macroscopic phenomenological point of view -the fluidity of the melt and the partial free enthalpy of the microscopic vacancies in the melt. All of the characteristics of the dynamics of the glass transition are essentially due to these two quantities.
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Romenski, E., I. Peshkov, M. Dumbser et F. Fambri. « A new continuum model for general relativistic viscous heat-conducting media ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 378, no 2170 (30 mars 2020) : 20190175. http://dx.doi.org/10.1098/rsta.2019.0175.
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The lack of formulation of macroscopic equations for irreversible dynamics of viscous heat-conducting media compatible with the causality principle of Einstein’s special relativity and the Euler–Lagrange structure of general relativity is a long-lasting problem. In this paper, we propose a possible solution to this problem in the framework of SHTC equations. The approach does not rely on postulates of equilibrium irreversible thermodynamics but treats irreversible processes from the non-equilibrium point of view. Thus, each transfer process is characterized by a characteristic velocity of perturbation propagation in the non-equilibrium state, as well as by an intrinsic time/length scale of the dissipative dynamics. The resulting system of governing equations is formulated as a first-order system of hyperbolic equations with relaxation-type irreversible terms. Via a formal asymptotic analysis, we demonstrate that classical transport coefficients such as viscosity, heat conductivity, etc., are recovered in leading terms of our theory as effective transport coefficients. Some numerical examples are presented in order to demonstrate the viability of the approach. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.
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Abourabia, Aly M., et Rabab A. Shahein. « Shock pattern solutions for viscous-collisional plasma ion acoustic waves in view of the linear theory of the non-equilibrium thermodynamics ». Canadian Journal of Physics 89, no 6 (juin 2011) : 673–87. http://dx.doi.org/10.1139/p11-037.
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In the framework of irreversible thermodynamics, we study nonlinear ion-acoustic waves (IAWs) in viscous and collisional plasmas. Electrons, which form the background, are assumed to be nonthermal. On account of ion viscosity and ion-electron collisions, we investigate using ion fluid equations. We study the effects of the nonthermally distributed electrons β and the temperature ratio σ (= Ti/Te) on the stability, where the stability for Burger’s equation is analyzed by two methods: the phase portrait method and irreversible thermodynamics relations at different values of σ and β. We usa a reductive perturbation technique, where the nonlinear evolution of an IAW is governed by the driven Burger equation. This equation is solved exactly by using two methods: the tanh-function method and the Cole–Hopf transformation. Both methods produce shock wave solutions, their results compared, and good agreement exists in most predictions. The analytical calculations show that an IAW propagates as a shock wave with subsonic speed. The flow velocity, pressure, number density, electrostatic potential, and thermodynamic characteristics are estimated and illustrated as functions of time t and the distance x. It is found via the tanh-function method that the amplitudes of the sought-for functions of the system are suppressed and move towards an equilibrium state at the highest value of β. The tanh-function method reveals an advantage over the Cole–Hopf method in the viscous and collisional cases of IAWs, where it satisfies the stability conditions at the highest value of β with the chosen σ values when applied to evaluate the Onsager relation.
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garfinkle, Moishe. « The thermodynamic natural path in chemical reaction kinetics ». Discrete Dynamics in Nature and Society 4, no 2 (2000) : 145–64. http://dx.doi.org/10.1155/s1026022600000145.
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The Natural Path approach to chemical reaction kinetics was developed to bridge the considerable gap between the Mass Action mechanistic approach and the non-mechanistic irreversible thermodynamic approach. The Natural Path approach can correlate empirical kinetic data with a high degree precision, as least equal to that achievable by the Mass-Action rate equations, but without recourse mechanistic considerations. The reaction velocities arising from the particular rate equation chosen by kineticists to best represent the kinetic behavior of a chemical reaction are the natural outcome of the Natural Path approach. Moreover, by virtue of its thermodynamic roots, equilibrium thermodynamic functions can be extracted from reaction kinetic data with considerable accuracy. These results support the intrinsic validity of the Natural Path approach.
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Abdel Wahid, Taha Zakaraia. « On the irreversible thermodynamic of a gas influenced by a thermal radiation force generated from a heated rigid flat plate ». Advances in Mechanical Engineering 12, no 10 (octobre 2020) : 168781402096504. http://dx.doi.org/10.1177/1687814020965043.
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In the present paper, the effect of the nonlinear thermal radiation (TR) on the neutral gas mixture in the unsteady state is investigated for the first time. The unsteady BGK technique of the Boltzmann kinetic equation (BKE) for a non-homogenous neutral gas (NHNG) is solved. The solution of the unsteady case makes the problem more general than the stationary case. For this purpose, the moments’ method, together with the traveling wave method, is applied. The temperature and concentration are calculated for each gas component and mixture for the first time. Furthermore, the study is held for aboard range of temperatures ratio parameter and a wide range of the molar fraction. The non-equilibrium distribution function (NEDF) is calculated for each gas component and the gas mixture. The significant non-equilibrium irreversible thermodynamic characteristics the entire system is acquired analytically. That technic allows us to investigate our model consistency with Boltzmann’s H-theorem, Le Chatelier’s principle, and thermodynamics laws. Moreover, the ratios among the further participation of the internal energy change (IEC) are evaluated via the Gibbs formula of total energy. The final results are utilized to the argon-helium NHNG at different magnitudes of radiation force (RF) strength and molar fraction parameters. 3D-graphics are presented to predict the behavior of the calculated variables, and the obtained results are theoretically discussed. The significance of this study is due to its vast applications in numerous fields, such as satellites, commercial, and various industrial applications.
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Pekař, Miloslav. « Thermodynamic framework for design of reaction rate equations and schemes ». Collection of Czechoslovak Chemical Communications 74, no 9 (2009) : 1375–401. http://dx.doi.org/10.1135/cccc2009010.
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It has been shown previously that rational thermodynamics provides general foundations of mass-action kinetic law from the principles of continuum, irreversible thermodynamics. Practical outcomes of this phenomenological theory are analyzed and compared with traditional kinetic approaches on the example of N2O decomposition. It is revealed that classical rate equations are only simplified forms of a polynomial approximation to a general rate function proved by the continuum thermodynamics. It is also shown that various special considerations that have been introduced formerly as additional hypothesis to satisfactorily describe experimental data are naturally included in the thermodynamic approach. The method, in addition, makes it possible to obtain more general mass-action-type rate equations that give better description of experimental data than the traditional ones. The method even reverses the classical kinetic paradigm – reaction scheme directly follows from the rate equation. Data fitting by this method also indicates connections to distinctions between processes at the molecular level and their representation by some macroscopic reaction network. The role of dependent and independent reactions in reaction kinetics and reaction schemes is clarified. A selected example demonstrates that this thermodynamic methodology may improve our design and understanding of thermodynamically and mathematically necessary and sufficient reaction schemes. The phenomenological theory thus sheds new, “thermodynamic” light on what has been and is done by generations of kineticists and gives new hints how to do it in a way consistent with non-equilibrium thermodynamics.
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Dai, Guang Ze, Lanying Yu, Jian Ke et Qing Qing Ni. « Analysis to Stress Relaxation Phenomena of Viscoelastic Materials by Means of Irreversible Thermodynamics (Ⅰ) ». Key Engineering Materials 297-300 (novembre 2005) : 365–70. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.365.
Texte intégralRésumé :
Through defining a piece of viscoelastic medium as a thermodynamic system described by the generalized coordinates in the stress relaxation process, the evolution equation is derived by making use of the 1st law of thermodynamics, the 2nd law of thermodynamics and the Onsager’s principle. Based on the general solutions of the evolution, the constitutive expressions of uniaxial stress relaxation are obtained for both ideal viscoelastic solid materials and ideal viscoelastic fluid one respectively, in terms of the situation whether the coordinates participating in the entropy production are in stable or neutrally stable equilibrium state. As the result, whether the stress relaxes to a constant or zero depends on whether the free energy in viscoelastic medium is left or not.
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Fialová, Simona, et František Pochylý. « Constitutive Equations for Magnetic Active Liquids ». Symmetry 13, no 10 (11 octobre 2021) : 1910. http://dx.doi.org/10.3390/sym13101910.
Texte intégralRésumé :
This article is focused on the derivation of constitutive equations for magnetic liquids. The results can be used for both ferromagnetic and magnetorheological fluids after the introduced simplifications. The formulation of constitutive equations is based on two approaches. The intuitive approach is based on experimental experience of non-Newtonian fluids, which exhibit a generally non-linear dependence of mechanical stress on shear rate; this is consistent with experimental experience with magnetic liquids. In these general equations, it is necessary to determine the viscosity of a liquid as a function of magnetic induction; however, these equations only apply to the symmetric stress tensor and can only be used for an incompressible fluid. As a result of this limitation, in the next part of the work, this approach is extended by the asymmetry of the stress tensor, depending on the angular velocity tensor. All constitutive equations are formulated in Cartesian coordinates in 3D space. The second approach to determining constitutive equations is more general: it takes the basis of non-equilibrium thermodynamics and is based on the physical approach, using the definition of density of the entropy production. The production of entropy is expressed by irreversible thermodynamic flows, which are caused by the effect of generalized thermodynamic forces after disturbance of the thermodynamic equilibrium. The dependence between fluxes and forces determines the constitutive equations between stress tensors, depending on the strain rate tensor and the magnetization vector, which depends on the intensity of the magnetic field. Their interdependencies are described in this article on the basis of the Curie principle and on the Onsager conditions of symmetry.
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Zakharov, A. Yu, et M. A. Zakharov. « Microscopic dynamic mechanism of equilibration in crystals : one-dimensional model ». Journal of Physics : Conference Series 2052, no 1 (1 novembre 2021) : 012053. http://dx.doi.org/10.1088/1742-6596/2052/1/012053.
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Abstract The dynamics of free vibrations of a chain of atoms is investigated taking into account the retardation of interactions. It is shown that all oscillations of the circuit are damped. The dynamics of forced vibrations of this chain of atoms is investigated. It is shown that, regardless of the initial conditions, the system passes into a stationary state of dynamic equilibrium with an external field, which depends both on the properties of the system and on the parameters of the external field. A non-statistical dynamic mechanism of the process of irreversible establishment of the state of thermodynamic equilibrium in both many-body and few-body systems is proposed.
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Sears, Matthew R., et Wayne M. Saslow. « Irreversible thermodynamics of transport across interfaces ». Canadian Journal of Physics 89, no 10 (octobre 2011) : 1041–50. http://dx.doi.org/10.1139/p11-093.
Texte intégralRésumé :
With spintronics applications in mind, we use irreversible thermodynamics to derive the rates of entropy production and heating near an interface when heat current, electric current, and spin current cross it. Associated with these currents are apparent discontinuities in temperature (ΔT), electrochemical potential (Δ[Formula: see text]), and spin-dependent “magnetoelectrochemical potential” (Δ[Formula: see text]). This work applies to magnetic semiconductors and insulators as well as metals, because of the inclusion of the chemical potential, μ, which is usually neglected in works on interfacial thermodynamic transport. We also discuss the (nonobvious) distinction between entropy production and heat production. Heat current and electric current are conserved, but spin current is not, so it necessitates a somewhat different treatment. At low temperatures or for large differences in material properties, the surface heating rate dominates the bulk heating rate near the surface. We also consider the case where bulk spin currents occur in equilibrium. Although a surface spin current (in A/m2) should yield about the same rate of heating as an equal surface electric current, production of such a spin current requires a relatively large “magnetization potential” difference across the interface.
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Vogel, Kristina, Thorsten Greinert, Monique Reichard, Christoph Held, Hauke Harms et Thomas Maskow. « Thermodynamics and Kinetics of Glycolytic Reactions. Part II : Influence of Cytosolic Conditions on Thermodynamic State Variables and Kinetic Parameters ». International Journal of Molecular Sciences 21, no 21 (25 octobre 2020) : 7921. http://dx.doi.org/10.3390/ijms21217921.
Texte intégralRésumé :
For systems biology, it is important to describe the kinetic and thermodynamic properties of enzyme-catalyzed reactions and reaction cascades quantitatively under conditions prevailing in the cytoplasm. While in part I kinetic models based on irreversible thermodynamics were tested, here in part II, the influence of the presumably most important cytosolic factors was investigated using two glycolytic reactions (i.e., the phosphoglucose isomerase reaction (PGI) with a uni-uni-mechanism and the enolase reaction with an uni-bi-mechanism) as examples. Crowding by macromolecules was simulated using polyethylene glycol (PEG) and bovine serum albumin (BSA). The reactions were monitored calorimetrically and the equilibrium concentrations were evaluated using the equation of state ePC-SAFT. The pH and the crowding agents had the greatest influence on the reaction enthalpy change. Two kinetic models based on irreversible thermodynamics (i.e., single parameter flux-force and two-parameter Noor model) were applied to investigate the influence of cytosolic conditions. The flux-force model describes the influence of cytosolic conditions on reaction kinetics best. Concentrations of magnesium ions and crowding agents had the greatest influence, while temperature and pH-value had a medium influence on the kinetic parameters. With this contribution, we show that the interplay of thermodynamic modeling and calorimetric process monitoring allows a fast and reliable quantification of the influence of cytosolic conditions on kinetic and thermodynamic parameters.
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Suhartono, Eko, Djaka Sasmita et RHA Sahirul Alim. « The Multielectrodes Oscillation System Studied by Irreversible Thermodynamics ». Indonesian Journal of Chemistry 1, no 1 (1 juin 2010) : 30–34. http://dx.doi.org/10.22146/ijc.21958.
Texte intégralRésumé :
Oscillation process that occurs in a system may be formed from non linear dynamic phenomena that far from equilibrium. Mechanism of oscillation in a chemical reaction system such as Belousov-Zhabotinski (B-Z) reaction is quite complex. For that reason, in order the irreversible thermodynamics that far from equilibrium can be more easily understood, the generation of oscillation in a system is tried to be investigated in this study. In this case, the author attempts to come up at the oscillation process coming from the potential difference between the couple of Pb and PbO2 electrodes which are parallel arranged to from eight channels in the solution of sulfuric acid with certain concentrations. The measurements of potential difference from PbllPbO2 electrode, i.e., from the eight channels all together, were done by the use of an interface connected to a computer and it worked with time interval of one second for the time duration of 5 hours. The data were then automatically recorded. Non periodic waves which were resulted from all channels have wave forms which are triangular and square. Oscillation process occurred in each channel of a couple of PbIIPbO2 electrodes can be compared with the process of spreading of action potentials that occur in nerve cells.
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Ghnatios, Chady, Iciar Alfaro, David González, Francisco Chinesta et Elias Cueto. « Data-Driven GENERIC Modeling of Poroviscoelastic Materials ». Entropy 21, no 12 (28 novembre 2019) : 1165. http://dx.doi.org/10.3390/e21121165.
Texte intégralRésumé :
Biphasic soft materials are challenging to model by nature. Ongoing efforts are targeting their effective modeling and simulation. This work uses experimental atomic force nanoindentation of thick hydrogels to identify the indentation forces are a function of the indentation depth. Later on, the atomic force microscopy results are used in a GENERIC general equation for non-equilibrium reversible–irreversible coupling (GENERIC) formalism to identify the best model conserving basic thermodynamic laws. The data-driven GENERIC analysis identifies the material behavior with high fidelity for both data fitting and prediction.
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Tsirlin, Anatolii, et Sergey Amelkin. « Dissipation and Conditions of Equilibrium for an Open Microeconomic System ». Open Systems & ; Information Dynamics 08, no 02 (juin 2001) : 157–68. http://dx.doi.org/10.1023/a:1011958701019.
Texte intégralRésumé :
An analogy between microeconomic and irreversible thermodynamic systems is shown. The concepts of economic irreversibility, dissipation of capital are introduced and conditions of minimal dissipation are obtained. Problems of optimal control of prices in the processes of resources exchange are solved and the extremal principle for the determination of stationary state of an open microeconomic system is formulated.
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Abourabia, Aly Maher, et Taha Zakaraia Abdel Wahid. « Kinetic and thermodynamic treatments of a neutral binary gas mixture affected by a nonlinear thermal radiation field ». Canadian Journal of Physics 90, no 2 (février 2012) : 137–49. http://dx.doi.org/10.1139/p11-151.
Texte intégralRésumé :
In the present study, the kinetic and the irreversible thermodynamic properties of a binary gas mixture, under the influence of a thermal radiation field, are presented from the molecular viewpoint. In a frame comoving with the fluid, the Bhatnagar–Gross–Krook model of the kinetic equation is analytically applied, using the Liu–Lees model. We apply the moment method to follow the behavior of the macroscopic properties of the binary gas mixture, such as the temperature and the concentration. The distinction and comparisons between the perturbed and equilibrium distribution functions are illustrated for each gas mixture component. From the viewpoint of the linear theory of irreversible thermodynamics we obtain the entropy, entropy flux, entropy production, thermodynamic forces, and kinetic coefficients. We verify the second law of thermodynamics and celebrated Onsager’s reciprocity relation for the system. The ratios between the different contributions of the internal energy changes, based upon the total derivatives of the extensive parameters, are estimated via Gibbs’ formula. The results are applied to the argon–neon binary gas mixture, for various values of both the molar fraction parameters and radiation field intensity. Graphics illustrating the calculated variables are drawn to predict their behavior and the results are discussed.
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Hütter, Markus, et Bob Svendsen. « On the Formulation of Continuum Thermodynamic Models for Solids as General Equations for Non-equilibrium Reversible-Irreversible Coupling ». Journal of Elasticity 104, no 1-2 (19 février 2011) : 357–68. http://dx.doi.org/10.1007/s10659-011-9327-4.
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Hodson, Stuart, et Richard Earlam. « Relationship of Salt Disparity and Its Consequence for Swelling in Biological Gels ». Applied Mechanics Reviews 48, no 10 (1 octobre 1995) : 681–83. http://dx.doi.org/10.1115/1.3005048.
Texte intégralRésumé :
New irreversible thermodynamic relationships are derived which explain why biological tissues tend to swell. In the course of their derivation, fresh concepts arize. In particular, the relationship of salt disparity is described which forbids diffusible salt generated chemical and osmotic potentials to be simultaneously at equilibrium in the presence of ionized macromolecules. This relationship is developed to generate a new intrinsic thermodynamic property which is termed gel pressure and which drives fluid flows.
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Öttinger, Hans Christian, Henning Struchtrup et Manuel Torrilhon. « Formulation of moment equations for rarefied gases within two frameworks of non-equilibrium thermodynamics : RET and GENERIC ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 378, no 2170 (30 mars 2020) : 20190174. http://dx.doi.org/10.1098/rsta.2019.0174.
Texte intégralRésumé :
In this work, we make a further step in bringing together different approaches to non-equilibrium thermodynamics. The structure of the moment hierarchy derived from the Boltzmann equation is at the heart of rational extended thermodynamics (RET, developed by Ingo Müller and Tommaso Ruggeri). Whereas the full moment hierarchy has the structure expressed in the general equation for the nonequilibrium reversible–irreversible coup- ling (GENERIC), the Poisson bracket structure of reversible dynamics postulated in that approach is a major obstacle for truncating moment hierarchies, which seems to work only in exceptional cases (most importantly, for the five moments associated with conservation laws). The practical importance of truncated moment hierarchies in rarefied gas dynamics and microfluidics motivates us to develop a new strategy for establishing the full GENERIC structure of truncated moment equations, based on non-entropy-producing irreversible processes associated with Casimir symmetry. Detailed results are given for the special case of 10 moments. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.
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Peng, Liangrong, et Liu Hong. « Recent Advances in Conservation–Dissipation Formalism for Irreversible Processes ». Entropy 23, no 11 (31 octobre 2021) : 1447. http://dx.doi.org/10.3390/e23111447.
Texte intégralRésumé :
The main purpose of this review is to summarize the recent advances of the Conservation–Dissipation Formalism (CDF), a new way for constructing both thermodynamically compatible and mathematically stable and well-posed models for irreversible processes. The contents include but are not restricted to the CDF’s physical motivations, mathematical foundations, formulations of several classical models in mathematical physics from master equations and Fokker–Planck equations to Boltzmann equations and quasi-linear Maxwell equations, as well as novel applications in the fields of non-Fourier heat conduction, non-Newtonian viscoelastic fluids, wave propagation/transportation in geophysics and neural science, soft matter physics, etc. Connections with other popular theories in the field of non-equilibrium thermodynamics are examined too.
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Zou, Chen-Juan, Yue Li, Jia-Kun Xu, Jia-Bin You, Ching Eng Png et Wan-Li Yang. « Geometrical Bounds on Irreversibility in Squeezed Thermal Bath ». Entropy 25, no 1 (9 janvier 2023) : 128. http://dx.doi.org/10.3390/e25010128.
Texte intégralRésumé :
Irreversible entropy production (IEP) plays an important role in quantum thermodynamic processes. Here, we investigate the geometrical bounds of IEP in nonequilibrium thermodynamics by exemplifying a system coupled to a squeezed thermal bath subject to dissipation and dephasing, respectively. We find that the geometrical bounds of the IEP always shift in a contrary way under dissipation and dephasing, where the lower and upper bounds turning to be tighter occur in the situation of dephasing and dissipation, respectively. However, either under dissipation or under dephasing, we may reduce both the critical time of the IEP itself and the critical time of the bounds for reaching an equilibrium by harvesting the benefits of squeezing effects in which the values of the IEP, quantifying the degree of thermodynamic irreversibility, also become smaller. Therefore, due to the nonequilibrium nature of the squeezed thermal bath, the system–bath interaction energy has a prominent impact on the IEP, leading to tightness of its bounds. Our results are not contradictory with the second law of thermodynamics by involving squeezing of the bath as an available resource, which can improve the performance of quantum thermodynamic devices.
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Khantuleva, Tatiana A., et Yurii I. Meshcheryakov. « Shock-Induced Mesoparticles and Turbulence Occurrence ». Particles 5, no 3 (16 septembre 2022) : 407–26. http://dx.doi.org/10.3390/particles5030032.
Texte intégralRésumé :
The development of a new approach to describe turbulent motions in condensed matter on the basis of nonlocal modeling of highly non-equilibrium processes in open systems is performed in parallel with an experiment studying the mesostructure of dynamically deformed solids. The shock-induced mesostructure formation inside the propagating waveform registered in real time allows the transient stages of non-equilibrium processes to be qualitatively and quantitatively revealed. A new nonlocal approach, developed on the basis of the nonlocal and retarded transport equations obtained within the non-equilibrium statistical physics, is used to describe the occurrence of turbulence. Within the approach, the reason for the transition to turbulence is that the non-equilibrium spatiotemporal correlation function generates the dynamic structures in the form of finite-size clusters on the mesoscale, with almost identical values of macroscopic densities moving as almost solid particles that can interact and rotate. The fragmentation of spatiotemporal correlations upon impact forms the mesoparticles that move at different speeds and transfer mass, momentum and energy-like wave packets. The movements recorded simultaneously at two scale levels indicate the energy exchange between them. Its description required a redefinition of the concept of energy far from local thermodynamic equilibrium. The experimental results show that the irreversible part of the dynamic mesostructure remains frozen into material as a new defect.
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Vogl, Thomas, Claudia Jatzke, Hans-Jürgen Hinz, Jörg Benz et Robert Huber. « Thermodynamic Stability of Annexin V E17G : Equilibrium Parameters from an Irreversible Unfolding Reaction†,‡ ». Biochemistry 36, no 7 (février 1997) : 1657–68. http://dx.doi.org/10.1021/bi962163z.
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Kaganovich, Boris M., Maxim S. Zarodnyuk et Sergey V. Yakshin. « Construction of trajectories of irreversible processes on the basis of equilibrium thermodynamic propositions ». Journal of Thermal Analysis and Calorimetry 133, no 2 (18 juin 2018) : 1225–32. http://dx.doi.org/10.1007/s10973-018-7368-7.
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Gaspard, Pierre. « Kinetics and thermodynamics of living copolymerization processes ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 374, no 2080 (13 novembre 2016) : 20160147. http://dx.doi.org/10.1098/rsta.2016.0147.
Texte intégralRésumé :
Theoretical advances are reported on the kinetics and thermodynamics of free and template-directed living copolymerizations. Until recently, the kinetic theory of these processes had only been established in the fully irreversible regime, in which the attachment rates are only considered. However, the entropy production is infinite in this regime and the approach to thermodynamic equilibrium cannot be investigated. For this purpose, the detachment rates should also be included. Inspite of this complication, the kinetics can be exactly solved in the regimes of steady growth and depolymerization. In this way, analytical expressions are obtained for the mean growth velocity, the statistical properties of the copolymer sequences, as well as the thermodynamic entropy production. The results apply to DNA replication, transcription and translation, allowing us to understand important aspects of molecular evolution. This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’.
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Mondal, Shrabani, Jonah S. Greenberg et Jason R. Green. « Dynamic scaling of stochastic thermodynamic observables for chemical reactions at and away from equilibrium ». Journal of Chemical Physics 157, no 19 (21 novembre 2022) : 194105. http://dx.doi.org/10.1063/5.0106714.
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Physical kinetic roughening processes are well-known to exhibit universal scaling of observables that fluctuate in space and time. Are there analogous dynamic scaling laws that are unique to the chemical reaction mechanisms available synthetically and occurring naturally? Here, we formulate an approach to the dynamic scaling of stochastic fluctuations in thermodynamic observables at and away from equilibrium. Both analytical expressions and numerical simulations confirm our dynamic scaling ansatz with associated scaling exponents, function, and law. A survey of common chemical mechanisms reveals classes that organize according to the molecularity of the reactions involved, the nature of the reaction vessel and external reservoirs, (non)equilibrium conditions, and the extent of autocatalysis in the reaction network. Varying experimental parameters, such as temperature, can cause coupled reactions capable of chemical feedback to transition between these classes. While path observables, such as the dynamical activity, have scaling exponents that are time-independent, the variance in the entropy production and flow can have time-dependent scaling exponents and self-averaging properties as a result of temporal correlations that emerge during thermodynamically irreversible processes. Altogether, these results establish dynamic universality classes in the nonequilibrium fluctuations of thermodynamic observables for well-mixed chemical reactions.
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Essig, A., et S. R. Caplan. « Water movement : does thermodynamic interpretation distort reality ? » American Journal of Physiology-Cell Physiology 256, no 3 (1 mars 1989) : C694—C698. http://dx.doi.org/10.1152/ajpcell.1989.256.3.c694.
Texte intégralRésumé :
In a recent theoretical analysis of water flow, Finkelstein (Water Movement Through Lipid Bilayers, Pores, and Plasma Membranes: Theory and Reality, 1987) has attacked the contributions of irreversible thermodynamics, stating that "the thermodynamic treatment of uphill water flow completely distorts reality." Instead he presents a mechanistic formulation. For a porous membrane, water flow is attributed to convection generated by a favorable hydrostatic pressure gradient within pores, even when in the presence of permeant solutes water moves against its chemical potential gradient; water flow may "drag", solute, to an extent determined by the solute partition coefficient, but the possibility that solute flow may drag water is excluded. We argue that this formulation violates the second law of thermodynamics. Water cannot move against its chemical potential gradient because of the influence of only part of the chemical potential gradient. Furthermore, the proposed mechanism requires that at one of the membrane-solution interfaces water must move against both its concentration gradient and the hydrostatic pressure gradient. Also considered by Finkelstein is the nature of the reflection coefficient sigma, a kinetic variable, which he concludes can be evaluated (in a porous membrane) by measurement of the (equilibrium) solute partition coefficient. We claim that in general it is not possible to evaluate a kinetic variable from measurements of equilibrium parameters alone. A valid kinetic analysis must incorporate the contribution of all coupled flows.
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Bustamante, Carlos. « Unfolding single RNA molecules : bridging the gap between equilibrium and non-equilibrium statistical thermodynamics ». Quarterly Reviews of Biophysics 38, no 4 (novembre 2005) : 291–301. http://dx.doi.org/10.1017/s0033583506004239.
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During the last 15 years, scientists have developed methods that permit the direct mechanical manipulation of individual molecules. Using this approach, they have begun to investigate the effect of force and torque in chemical and biochemical reactions. These studies span from the study of the mechanical properties of macromolecules, to the characterization of molecular motors, to the mechanical unfolding of individual proteins and RNA. Here I present a review of some of our most recent results using mechanical force to unfold individual molecules of RNA. These studies make it possible to follow in real time the trajectory of each molecule as it unfolds and characterize the various intermediates of the reaction. Moreover, if the process takes place reversibly it is possible to extract both kinetic and thermodynamic information from these experiments at the same time that we characterize the forces that maintain the three-dimensional structure of the molecule in solution. These studies bring us closer to the biological unfolding processes in the cell as they simulate in vitro, the mechanical unfolding of RNAs carried out in the cell by helicases. If the unfolding process occurs irreversibly, I show here that single-molecule experiments can still provide equilibrium, thermodynamic information from non-equilibrium data by using recently discovered fluctuation theorems. Such theorems represent a bridge between equilibrium and non-equilibrium statistical mechanics. In fact, first derived in 1997, the first experimental demonstration of the validity of fluctuation theorems was obtained by unfolding mechanically a single molecule of RNA. It is perhaps a sign of the times that important physical results are these days used to extract information about biological systems and that biological systems are being used to test and confirm fundamental new laws in physics.
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Jou, David. « Relationships between rational extended thermodynamics and extended irreversible thermodynamics ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 378, no 2170 (30 mars 2020) : 20190172. http://dx.doi.org/10.1098/rsta.2019.0172.
Texte intégralRésumé :
We consider a few conceptual questions on extended thermodynamics, with the aim to contribute to a higher contact between rational extended thermodynamics and extended irreversible thermodynamics. Both theories take a number of fluxes as independent variables, but they differ in the formalism being used to deal with the exploitation of the second principle (rational thermodynamics in the first one and classical irreversible thermodynamics in the second one). Rational extended thermodynamics is more restricted in the range of systems to be analysed, but it is able to obtain a wider number of restrictions and deeper specifications from the second law. By contrast, extended irreversible thermodynamics is more phenomenological, its mathematical formalism is more elementary, but it may deal with a wider diversity of systems although with less detail. Further comparison and dialogue between both branches of extended thermodynamics would be useful for a fuller deployment and deepening of extended thermodynamics. Besides these two approaches, one should also consider the Hamiltonian approach, formalisms with internal variables, and more microscopic approaches, based on kinetic theory or on non-equilibrium ensemble formalisms. This article is part of the theme issue ‘Fundamental aspects of nonequilibrium thermodynamics’.
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Chakraborty, Uday. « Reversible and Irreversible Potentials and an Inaccuracy in Popular Models in the Fuel Cell Literature ». Energies 11, no 7 (15 juillet 2018) : 1851. http://dx.doi.org/10.3390/en11071851.
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Modeling is an integral part of fuel cell design and development. This paper identifies a long-standing inaccuracy in the fuel cell modeling literature. Specifically, it discusses an inexact insertion, in popular models, of cell/stack current into Nernst’s equation in the derivation of output (load) voltage. The origin of the inaccuracy is traced to the nature of reversible and irreversible potentials (equilibrium and non-equilibrium states) in the cell. The significance of the inaccuracy is explained in the context of the electrochemistry and thermodynamics of the fuel cell.