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Power Density Analysis and Multi-Objective Optimization for an Irreversible Dual Cycle J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-04-29 Yanlin Ge, Shuangshuang Shi, Lingen Chen, Difeng Zhang, Huijun Feng
Considering the various irreversibility conditions caused by heat transfer and working processes in a dual cycle, the power density performance is optimized by applying finite-time thermodynamics theory, and multi-objective optimization is performed by using NSGA-II. The effects of cut-off ratio, maximum cycle temperature ratio, and various losses by heat transfer and working processes on the relationships
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Thermodynamical Foundations of Closed Discrete Non-Equilibrium Systems J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-04-04 Wolfgang Muschik
Some tools of Non-Equilibrium Thermodynamics of closed discrete systems are considered: the non-equilibrium state space, the non-equilibrium entropy as a state function and its connection with the entropy production, Clausius’ inequality, equilibrium and accompanying processes. Why can the thermostatic temperature be used successfully in thermal engineering even in cases of non-equilibrium?
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Internal Variables as a Tool for Extending Navier-Stokes Equations J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-04-04 Arkadi Berezovski
The formalism of the internal variable theory is applied to extend Navier-Stokes equations. The internal variable theory provides a thermodynamically consistent derivation of constitutive relations and equations of motion without a priori specifying the nature of internal variables. Both single and dual internal variables cases are thoroughly examined. The similarities and differences of the approaches
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Nonlinear Thermal Transport with Inertia in Thin Wires: Thermal Fronts and Steady States J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-03-31 Michele Sciacca, David Jou
In a series of papers we have obtained results for nonlinear heat transport when thin wires exchange heat non-linearly with the surroundings, with particular attention to propagating solitons. Here we obtain and discuss new results related to the propagation of nonlinear heat fronts and some conceptual aspects referring to the application of the second principle of thermodynamics to some nonlinear
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Thermotics As an Alternative Nonequilibrium Thermodynamic Approach Suitable for Real Thermoanalytical Measurements: A Short Review J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-03-31 Jaroslav Šesták, Robert Černý
The general concept of temperature is thermodynamically defined in equilibrium somehow predictable even for non-equilibrium; however, it presents some still controversial aspects, as has been shown in a number of studies and reviews that have been published so far. Equilibrium concepts are often extrapolated to apply in micro-localized equilibrium and then appended to non-equilibrium in its entirety
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Thermal Shear Waves Induced in Mesoscopic Liquids at Low Frequency Mechanical Deformation J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-03-31 Eni Kume, Laurence Noirez
We show that a confined viscous liquid emits a dynamic thermal response upon applying a low frequency (∼1 Hz) shear excitation. Hot and cold thermal waves are observed in situ at atmospheric pressure and room temperature, in a viscous liquid (polypropylene glycol) at various thicknesses ranging from 100 µm up to 340 µm, upon applying a mechanical oscillatory shear strain. The observed thermal effects
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A Thermodynamical Description of Third Grade Fluid Mixtures J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-03-29 Matteo Gorgone, Patrizia Rogolino
A complete thermodynamical analysis for a non-reacting binary mixture exhibiting the features of a third grade fluid is analyzed. The constitutive functions are allowed to depend on the mass density of the mixture and the concentration of one of the constituents, together with their first and second order gradients, on the specific internal energy of the mixture with its first order gradient, and on
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Pattern Formation in Thermal Convective Systems: Spatio-Temporal Thermal Statistics, Emergent Flux, and Local Equilibrium J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-03-23 Atanu Chatterjee, Takahiko Ban, Atsushi Onizuka, Germano Iannacchione
We discuss spatio-temporal pattern formation in two separate thermal convective systems. In the first system, hydrothermal waves (HTW) are modeled numerically in an annular channel. A temperature difference is imposed across the channel, which induces a surface tension gradient on the free surface of the fluid, leading to a surface flow towards the cold side. The flow pattern is axially symmetric along
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Variational Approach to Fluid-Structure Interaction via GENERIC J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-10 Dirk Peschka, Andrea Zafferi, Luca Heltai, Marita Thomas
We present a framework to systematically derive variational formulations for fluid-structure interaction problems based on thermodynamical driving functionals and geometric structures in different coordinate systems by suitable transformations within this formulation. Our approach provides a promising basis to construct structure-preserving discretization strategies.
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Optimizing the Piston Paths of Stirling Cycle Cryocoolers J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-08 Raphael Paul, Karl Heinz Hoffmann
The ideal Stirling cycle provides a clear control strategy for the piston paths of ideal representations of Stirling cycle machines. For non-equilibrium Stirling cycle machines however, piston paths aiming to emulate the ideal cycle’s four strokes will not necessarily yield best performance. In this contribution, we ask the question: What are the COP-optimal piston paths for specific non-equilibrium
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Effect of Cross-Sectional Geometry on Hydrothermal Behavior of Microchannel Heat Sink J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-08 Faraz Ahmad, Fawad Ahmed, Husan Ali, Zabdur Rehman, Muhammad Suleman, Izaz Raouf
The aim of this paper is to numerically analyze the hydrothermal behavior of different cross-sectional geometries of microchannel heat sinks (MCHSs) and conduct a comparative analysis of traditional and non-traditional designs using ANSYS Fluent. It is expected that the proposed design discussed in this paper will improve the performance of MCHSs by maximizing the cooling capability and minimizing
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Sources of Finite Speed Temperature Propagation J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-08 Paolo Maria Mariano, Marco Spadini
The relation between heat flux and temperature gradient has been considered as a constitutive structure or as a balance law in different approaches. Both views may allow a description of heat conduction characterized by finite speed propagation of temperature disturbances. Such a result, which overcomes Fourier’s drawback of infinite speed propagation, can be obtained also by considering insufficient
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Non-Linear Stability and Non-Equilibrium Thermodynamics—There and Back Again J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-07 Mark Dostalík, Vít Průša
We discuss the role of thermodynamics in non-linear stability analysis of spatially distributed dissipative systems governed by non-linear partial differential equations. We document profound interplay between various concepts in thermodynamics on one side and non-linear stability analysis on the other side, and subsequently we summarize and comment on various results regarding the non-linear stability
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A Robust Physics-Based Calculation of Evolving Gas–Liquid Interfaces J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-04 Lukáš Šatura, Mária Minichová, Michal Pavelka, Juraj Kosek, Alexandr Zubov
Density gradient theory describes the evolution of diffuse interfaces in both mixtures and pure substances by minimization of the total free energy, which consists of a non-convex bulk part and an interfacial part. Minimization of the bulk free energy causes phase separation while building up the interfacial free energy (proportional to the square of gradients of the species’ densities) and it results
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Non-Linear Heat Transport Effects in Systems with Defects J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-02-02 David Jou, Liliana Restuccia
In this paper we explore several aspects of the influence of fixed and of mobile defects on the thermal conductivity of materials. In particular, we investigate the effects of the temperature and defect concentration dependence of the conductivity on phononic diodes and transistors and on the non-linear thermal conductivity dependent on the heat flux in thermal superlattices.
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Frontmatter J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01
Article Frontmatter was published on January 1, 2022 in the journal Journal of Non-Equilibrium Thermodynamics (volume 47, issue 1).
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Theoretical Analysis of Activation Energy Effect on Prandtl–Eyring Nanoliquid Flow Subject to Melting Condition J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Ikram Ullah, Rashid Ali, Hamid Nawab, Abdussatar, Iftikhar Uddin, Taseer Muhammad, Ilyas Khan, Kottakkaran Sooppy Nisar
This study models the convective flow of Prandtl–Eyring nanomaterials driven by a stretched surface. The model incorporates the significant aspects of activation energy, Joule heating and chemical reaction. The thermal impulses of particles with melting condition is addressed. The system of equations is an ordinary differential equation (ODE) system and is tackled numerically by utilizing the Lobatto
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Internal Structure and Heat Conduction in Rigid Solids: A Two-Temperature Approach J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Ruth Estephania Gonzalez-Narvaez, Mariano López de Haro, Federico Vázquez
A non-Fourier thermal transport regime characterizes the heat conduction in solids with internal structure. Several thermodynamic theories attempt to explain the separation from the Fourier regime in such kind of systems. Here we develop a two-temperature model to describe the non-Fourier regime from the principles of non-equilibrium thermodynamics. The basic assumption is the existence of two well-separated
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A Case Study of Non-Fourier Heat Conduction Using Internal Variables and GENERIC J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Mátyás Szücs, Michal Pavelka, Róbert Kovács, Tamás Fülöp, Péter Ván, Miroslav Grmela
Applying simultaneously the methodology of non-equilibrium thermodynamics with internal variables (NET-IV) and the framework of General Equation for the Non-Equilibrium Reversible–Irreversible Coupling (GENERIC), we demonstrate that, in heat conduction theories, entropy current multipliers can be interpreted as relaxed state variables. Fourier’s law and its various extensions—the Maxwell–Cattaneo–Vernotte
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Significance of Entropy Generation and the Coriolis Force on the Three-Dimensional Non-Darcy Flow of Ethylene-Glycol Conveying Carbon Nanotubes (SWCNTs and MWCNTs) J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Ikram Ullah, Tasawar Hayat, Arsalan Aziz, Ahmed Alsaedi
Nanofluids based on CNTs/ethylene glycol have a potential role in contributing to industrial applications like heat exchangers, domestic refrigerator, electronics cooling, etc. The aim and novelty of the present research is to communicate the significance of the Coriolis force and Darcy-Forchheimer stretched flow of ethylene glycol (EG) conveying carbon nanotubes (CNTs) in a rotating frame. Furthermore
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Maximum Work Rate Extractable from Energy Fluxes J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Viorel Badescu
A general formalism is developed to evaluate the amount of work extractable from energy fluxes. It covers nonequilibrium cases when the concept of exergy is not relevant. The rate of work deficiency, which has been previously introduced as the total loss of exergy, is defined here as the total loss of work, which would have resulted if all the work were lost to the environment. New performance indicators
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Spectral Properties of Dissipation J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Peter Ván, Róbert Kovács, Federico Vázquez
The novel concept of spectral diffusivity is introduced to analyze the dissipative properties of continua. The dissipative components of a linear system of evolution equations are separated into noninteracting parts. This separation is similar to mode analysis in wave propagation. The new modal quantities characterize dissipation and are best interpreted as effective diffusivities, or, in case of the
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Over-Equilibrium as a Result of Conservatively-Perturbed Equilibrium (Acyclic and Cyclic Mechanisms) J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Vitaliy R. Trishch, Yuriy O. Beznosyk, Denis Constales, Gregory S. Yablonsky
The effect of over-equilibrium, i. e., the effect at which the concentration of some substance is higher than the corresponding equilibrium value, is demonstrated for two types of ideal chemical reactors, continuously stirred tank reactor (CSTR) and plug-flow reactor (PFR), respectively, under conditions of conservatively perturbed-equilibrium (CPE). Two types of complex chemical mechanisms are analyzed
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Transient, Sub-Continuum, Heat Conduction in Irregular Geometries J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2022-01-01 Saad Bin Mansoor, Bekir S. Yilbas
Phonon transfer in irregular shapes is important for assessing the influence of shape effect on thermal transport characteristics of low-scale films. It becomes critical for evaluating the contribution of the scattering phonons to the phonon intensity distribution inside the film. Hence, the sub-continuum ballistic-diffusive model is incorporated to formulate the phonon transport in an irregular geometry
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The Role of Internal Irreversibilities in the Performance and Stability of Power Plant Models Working at Maximum ϵ-Ecological Function J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-20 Gabriel Valencia-Ortega, Sergio Levario-Medina, Marco Antonio Barranco-Jiménez
The proposal of models that account for the irreversibilities within the core engine has been the topic of interest to quantify the useful energy available during its conversion. In this work, we analyze the energetic optimization and stability (local and global) of three power plants, nuclear, combined-cycle, and simple-cycle ones, by means of the Curzon–Ahlborn heat engine model which considers a
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Size Effects and Beyond-Fourier Heat Conduction in Room-Temperature Experiments J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-16 Anna Fehér, Norbert Lukács, László Somlai, Tamás Fodor, Mátyás Szücs, Tamás Fülöp, Peter Ván, Róbert Kovács
It is a long-lasting task to understand heat conduction phenomena beyond Fourier. Besides the low-temperature experiments on extremely pure crystals, it has turned out recently that heterogeneous materials with macro-scale size can also show thermal effects that cannot be modeled by the Fourier equation. This is called over-diffusive propagation, different from low-temperature observations, and is
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The Maximum Power Cycle Operating Between a Heat Source and Heat Sink with Finite Heat Capacities J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-07 Osama M. Ibrahim, Raed I. Bourisli
This study aims to identify the thermodynamic cycle that produces the maximum possible power output from a heat source and sink with finite heat capacities. Earlier efforts used sequential Carnot cycles governed by heat transfer rate equations to determine the maximum power cycle. In this paper, a hypothesis is proposed where the heat capacities of the heat addition and rejection processes of the proposed
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Frontmatter J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01
Article Frontmatter was published on July 1, 2021 in the journal Journal of Non-Equilibrium Thermodynamics (volume 46, issue 3).
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Time-Independent Plasticity Formulated by Inelastic Differential of Free Energy Function J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Qiang Yang, Chaoyi Li, Yaoru Liu
The authors presented a time-independent plasticity approach, where a typical plastic-loading process is viewed as an infinitesimal state change of two neighboring equilibrium states, and the yield and consistency conditions are formulated based on the conjugate forces of the internal variables. In this paper, a stability condition is proposed, and the yield, consistency, and stability conditions are
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A Three-Dimensional Simulation Analysis of Fluid Flow and Heat Transfer in Microchannel Heat Sinks with Different Structures J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Jienan Shen, Xiuxiu Li, Yongsheng Zhu, Boya Zhang, Hang Guo, Baolin Liu, Hong Chen
Numerical studies have been performed to analyze the fluid flow and heat transfer characteristics of nine microchannel heat sinks (MCHS) with different shapes and different arrangements of the ribs and cavities on the sidewalls, using three common shapes (square, triangle, and circular) of ribs or cavities as the basic structure in this work. The boundary conditions, governing equations, friction factor
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Hydrothermal Investigation of the Performance of Microchannel Heat Sink with Ribs Employed on Side Walls J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Faraz Ahmad, Taqi Ahmad Cheema, Amjid Khan, Muhammad Mohib-Ur-Rehman, Hasan Yildizhan
In the present study, conjugate heat transfer and fluid flow performance of microchannel heat sink has been investigated using dimensionless parameters. Novel ribs of four different types are introduced on the side walls of channel, which include trapezoidal ribs, rectangular ribs, hydrofoil ribs, and elliptical ribs. The performance evaluation has been conducted by comparing friction factor ( f )
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Modeling and Performance Optimization of Double-Resonance Electronic Cooling Device with Three Electron Reservoirs J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Zemin Ding, Susu Qiu, Lingen Chen, Wenhua Wang
In this paper, a new model of the three-electron reservoir energy selective electronic cooling device applying double-resonance energy filters is proposed by using finite time thermodynamics. The analytical formulas of the main performance parameters for the double-resonance three-electron reservoir cooling device are derived. The optimal cooling load and coefficient of performance of the cooling device
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Self-Driven Reverse Thermal Engines Under Monotonous and Oscillatory Optimal Operation J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Viorel Badescu
The complex time-dependent heat and electromagnetic energy transfer in a new type of reverse thermal engine is analyzed. The reverse thermal engine consists of a cold body, a Peltier element and an electric circuit containing an inductor with controllable inductance. This system allows cooling a body below the ambient temperature. The inductor acts as an accumulator of magnetic energy, receiving electrical
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Estimating Entropy Generation Rate for Ballistic-Diffusive Phonon Transport Using Effective Thermal Conductivity J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-07-01 Saad Bin Mansoor, Bekir S. Yilbas
The entropy generation rate in a low dimensional film is formulated incorporating the heat flux and effective thermal conductivity of the film material. In the analysis, the mathematical formulation employed is kept the same as that used in the diffusive regime. However, the entropy generation rate is corrected by replacing the bulk thermal conductivity with an effective thermal conductivity evaluated
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Continuum Modeling Perspectives of Non-Fourier Heat Conduction in Biological Systems J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-06-18 Ákos Sudár, Gergely Futaki, Róbert Kovács
The thermal modeling of biological systems is increasingly important in the development of more advanced and more precise techniques such as ultrasound surgery. One of the primary barriers is the complexity of biological materials: the geometrical, structural, and material properties vary in a wide range. In the present paper, we focus on the continuum modeling of heterogeneous materials of biological
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On the Physical Background of Nerve Pulse Propagation: Heat and Energy J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-05-18 Tanel Peets, Kert Tamm, Jüri Engelbrecht
Recent studies have revealed the complex structure of nerve signals in axons. Besides the electrical signal, mechanical and thermal effects are also detected in many experimental studies. In this paper, the mathematical models of heat generation are analysed within the framework of a general model derived earlier by the authors. The main mechanisms of heat generation are seemingly Joule heating and
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Learning Thermodynamically Stable and Galilean Invariant Partial Differential Equations for Non-Equilibrium Flows J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-05-17 Juntao Huang, Zhiting Ma, Yizhou Zhou, Wen-An Yong
In this work, we develop a method for learning interpretable, thermodynamically stable and Galilean invariant partial differential equations (PDEs) based on the conservation-dissipation formalism of irreversible thermodynamics. As governing equations for non-equilibrium flows in one dimension, the learned PDEs are parameterized by fully connected neural networks and satisfy the conservation-dissipation
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Non-Equilibrium Molecular Dynamics Study of the Influence of Branching on the Soret Coefficient of Binary Mixtures of Heptane Isomers J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-05-12 Xiaoyu Chen, Ruquan Liang, Lichun Wu, Gan Cui
Equimolar mixtures composed of isomers were firstly used to investigate the molecular branching effect on thermal diffusion behavior, which was not disturbed by factors of molecular mass and composition in this work. Eight heptane isomers, including n-heptane, 2-methylhexane, 3-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane and 3-ethylpentane, were
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Frontmatter J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01
Article Frontmatter was published on April 1, 2021 in the journal Journal of Non-Equilibrium Thermodynamics (volume 46, issue 2).
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Modeling of Separation in a Binary Mixture with Negative Soret Effect in a Cylindrical Thermogravitational Column J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Sofia V. Kozlova, Ilya I. Ryzhkov, M. Mounir Bou-Ali
A numerical simulation of convective instability of a binary fluid with negative Soret effect in a cylindrical thermogravitational column is performed. The general problem statement, including equations of motion and heat/mass transfer with boundary conditions, are written in cylindrical coordinates. This is implemented in order to take into account the impact of the column geometry on the separation
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Thermodynamic Characterization of Red Blood Cell Suspension and Band 3 Protein Oxy-Deoxygenating Functionality: Comparative Study J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Francesco Farsaci, Ester Tellone, Annamaria Russo, Antonio Galtieri, Silvana Ficarra
The importance of studying storage alterations in erythrocytes is highlighted by the need to understand changes that could potentially serve to optimize the storage system. With this aim, the non-equilibrium thermodynamic theory with internal variables was introduced, and perturbing the erythrocyte samples with a harmonic electric field some functions of the theory have been determined varying in the
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Non-Equilibrium Thermodynamic Analysis of Flash Evaporation Process in Vacuum Ice Making J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Lingeng Zou, Xuelai Zhang
Traditional equilibrium thermodynamics can only solve a few equilibrium processes composed of continuous stable equilibrium states. However, the vacuum flash evaporation process is a typical unsteady process. The study of non-equilibrium thermodynamics of the two-phase flow model is helpful to improve our understanding of the basic law of the flash evaporation process. Based on the theory of non-equilibrium
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Performance Optimization for a Multielement Thermoelectric Refrigerator with Linear Phenomenological Heat Transfer Law J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Lingen Chen, Fankai Meng, Yanlin Ge, Huijun Feng
A model of a multielement thermoelectric refrigerator with another linear heat transfer law, the linear phenomenological heat transfer law Q∝Δ(1/T)Q\propto \Delta (1/T), is established. The refrigerating capacity and coefficient of performance (COP) are analyzed and optimized. The junction temperature solution equations are derived. The optimum electrical currents and thermal conductance allocation
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Effect of Copper Electrode Geometry on Electrofreezing of the Phase-Change Material CaCl2·6H2O J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Ahmad Swandi, Annisa Rahman, Risky Afandi Putri, Radhiah Anggraini, Daniel Kurnia, Surjamanto Wonorahardjo, Inge Magdalena Sutjahja
The development of effective active thermal energy storage systems requires an understanding of how electrode geometry affects the electrofreezing process. This study aimed to observe the nucleation behavior of an inorganic phase-change material, CaCl 2 ·6H 2 O, using a DC electric field and various copper electrode geometries. The effects of both the electrode diameter (d=0.5d=0.5 and 0.7 mm) and
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Modeling of Irreversible Two-Stage Combined Thermal Brownian Refrigerators and Their Optimal Performance J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Congzheng Qi, Zemin Ding, Lingen Chen, Yanlin Ge, Huijun Feng
This paper establishes a model of an irreversible two-stage combined thermal Brownian refrigerator with an intermediate heat reservoir by combining finite time thermodynamics with non-equilibrium thermodynamics. The model is composed of two irreversible thermal Brownian refrigerators working in series. The combined thermal Brownian refrigerator works among three constant temperature heat reservoirs
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Entropy Optimization in Nonlinear Mixed Convective Flow of Nanomaterials Through Porous Space J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Tasawar Hayat, Ikram Ullah, Ahmad Alsaedi, Shaher Momani
Our intention in this article is to investigate entropy optimization in nonlinear mixed convective unsteady magnetohydrodynamic flow of nanomaterials in porous space. An exponentially stretched sheet creates the liquid flow. Nanomaterial is considered electrically conducting. The concentration and energy expressions comprise viscous dissipation, Joule heating, thermophoresis and Brownian motion aspects
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Thermal Stress Development in Low Dimensional Silicon Film: An Analytical Approach J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-04-01 Bekir Sami Yilbas, R. S. M. Alassar, Ahmad Y. Al-Dweik
Thermal excitation of the low dimensional silicon film is introduced and an analytical approach is adopted for the solution of the transport equation. In the analysis, the phonon radiative transport equation is converted into an integral form of the Fredholm equation of the second kind. The analytical approach is extended to include the formulation of thermal stresses for the following cases: (i) stress-free
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Experimental study and kinetics modeling of gas hydrate formation of methane–ethane mixture J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-02-28 Parisa Naeiji, Farshad Varaminian
. In this study, gas hydrate formation kinetics of methane and ethane binary mixtures has been studied and data of mixed methane–ethane hydrate formation at 0.1, 0.2, 0.3, 0.5, 0.68, 0.8, and 0.9 mole fractions of methane and at a temperature of 277.15 K and an initial pressure of approximately 3.6 MPa were collected. The thermodynamic natural path was used for modeling the hydrate formation rate in
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The Ideal Gas in Slow Time J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Christopher Essex, Bjarne Andresen
Abstract We continue our exploration of thermodynamics at long observational timescales, “slow time,” by including turbulent dynamics leading to a condition of fluctuating local equilibrium. Averaging these fluctuations in wind speed and temperature results in a velocity distribution with heavy tails which, however, are necessarily truncated at some large molecular speed preserving all moments of the
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Polydisperse Colloids Two-Moment Diffusion Model Through Irreversible Thermodynamics Considerations J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Mohamed Bouzghaia, Ferhat Souidi, Zakaria Larbi
Abstract This study deals with the problem of diffusion for polydisperse colloids. The resolution of this complex problem usually requires computationally expensive numerical models. By considering the number of colloidal particles and their mass as independent variables, the equations of state for a dilute polydisperse colloid are derived on a statistical mechanics basis. Irreversible thermodynamics
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Open-Circuit Voltage Comes from Non-Equilibrium Thermodynamics J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Diego del Olmo, Michal Pavelka, Juraj Kosek
Abstract Originally derived by Walther Nernst more than a century ago, the Nernst equation for the open-circuit voltage is a cornerstone in the analysis of electrochemical systems. Unfortunately, the assumptions behind its derivation are often overlooked in the literature, leading to incorrect forms of the equation when applied to complex systems (for example, those with ion-exchange membranes or involving
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A Framework of Nonequilibrium Statistical Mechanics. II. Coarse-Graining J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Alberto Montefusco, Mark A. Peletier, Hans Christian Öttinger
Abstract For a given thermodynamic system, and a given choice of coarse-grained state variables, the knowledge of a force-flux constitutive law is the basis for any nonequilibrium modeling. In the first paper of this series we established how, by a generalization of the classical fluctuation-dissipation theorem (FDT), the structure of a constitutive law is directly related to the distribution of the
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Exergy-Based Ecological Optimization of an Irreversible Quantum Carnot Heat Pump with Spin-1/2 Systems J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Xiaowei Liu, Lingen Chen, Yanlin Ge, Huijun Feng, Feng Wu, Giulio Lorenzini
Abstract Based on an irreversible quantum Carnot heat pump model in which spin-1/2 systems are used as working substance, an exergy-based ecological function and some other important parameters of the model heat pump are derived. Numerical examples are provided to investigate its ecological performance characteristics. The influences of various irreversibility factors on the ecological performance
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A Framework of Nonequilibrium Statistical Mechanics. I. Role and Types of Fluctuations J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Hans Christian Öttinger, Mark A. Peletier, Alberto Montefusco
Abstract Understanding the fluctuations by which phenomenological evolution equations with thermodynamic structure can be enhanced is the key to a general framework of nonequilibrium statistical mechanics. These fluctuations provide an idealized representation of microscopic details. We consider fluctuation-enhanced equations associated with Markov processes and elaborate the general recipes for evaluating
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Natural Convection Around a Locally Heated Circular Cylinder Placed in a Rectangular Enclosure J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-26 Nepal Chandra Roy, Md. Anwar Hossain, Rama Subba Reddy Gorla, Sadia Siddiqa
Abstract Natural convective flow and heat transfer around a locally heated circular cylinder kept in a rectangular enclosure are investigated. At first, a problem valid for a rectangular domain is formulated and then an analytical coordinate transformation is introduced to map the rectangular domain to the physical domain considered here. Based on the coordinate transformation, a set of governing equations
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Frontmatter J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2021-01-01
Article Frontmatter was published on January 1, 2021 in the journal Journal of Non-Equilibrium Thermodynamics (volume 46, issue 1).
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Membrane Transport in Concentration Polarization Conditions: Evaluation of S-Entropy Production for Ternary Non-Electrolyte Solutions J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2020-10-25 Andrzej Ślęzak, Sławomir Grzegorczyn, Kornelia M. Batko, Wiesław Pilis, Robert Biczak
Abstract A model of the S-entropy production in a system with a membrane which separates non-electrolyte aqueous solutions was presented. The differences between fluxes in non-homogeneous and homogeneous conditions for volume and solute fluxes, respectively, are non-linear functions of the glucose osmotic pressure difference (OPD) in ranges dependent on the initial ethanol OPD. A decrease of ethanol
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Three-Dimensional Ballistic-Diffusive Heat Transport in Silicon: Transient Response and Thermal Conductivity J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2020-10-25 Saad Bin Mansoor, Bekir S. Yilbas
Abstract Phonons are the main contributors to thermal energy transfer in thin films. The size dependence of the thermal transport characteristics alters the film properties such as thermal conductivity. Hence, in the present study, three-dimensional, transient phonon transport in dielectric material is studied through the Equation of Phonon Radiative Transport (EPRT) to assess the size dependence of
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Circular Microchannel Heat Sink Optimization Using Entropy Generation Minimization Method J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2020-10-25 Krishan Kumar, Rajan Kumar, Rabinder Singh Bharj
Abstract The performance of the microchannel heat sink (MCHS) in electronic applications needs to be optimized corresponding to the number of channels (N). In this study optimization of the number of channels corresponding to the diameter of the microchannel ( D N {D_{N}}) using an entropy generation minimization approach is achieved for the MCHS used in electronic applications. The numerical study
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Application of Irreversible Thermodynamics to Diffusion in Solids with Internal Surfaces J. Non Equilib. Thermodyn. (IF 3.328) Pub Date : 2020-10-25 Anna G. Knyazeva
Abstract Two types of additional variables were included in the set of state variables and were used for a thermodynamic description of diffusion in an ordinary thermodynamic system. Vacancies are included in the mass balance. Internal surfaces are massless but are characterized by some energy, which is included in the energy balance of the thermodynamic system. Fluxes of components, vacancies, and