Article Frontmatter was published on April 1, 2021 in the journal Journal of Non-Equilibrium Thermodynamics (volume 46, issue 2).

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Article Frontmatter was published on January 1, 2021 in the journal Journal of Non-Equilibrium Thermodynamics (volume 46, issue 1).

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

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

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

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

Abstract Transport coefficients (like diffusion and thermodiffusion) are the key parameters to be studied in non-equilibrium thermodynamics. For practical applications, it is important to predict them based on the thermodynamic parameters of a mixture under study: pressure, temperature, composition, and thermodynamic functions, like enthalpies or chemical potentials. The current study develops a thermodynamic

Abstract This study deals with the entropy generation in magnetized blood flow through a channel. The blood is modeled as a non-Newtonian fluid that circulates by a uniform peristaltic wave with slip at the boundaries. An inertia free flow is considered using an approximation of the long-wavelength peristaltic wave. The governing equations of the flow are formulated and numerically solved using computational

Abstract A mathematical model for mixed convection flow of a nanofluid along a vertical wavy surface has been studied. Numerical results reveal the effects of the volume fraction of nanoparticles, the axial distribution, the Richardson number, and the amplitude/wavelength ratio on the heat transfer of Al2O3-water nanofluid. By increasing the volume fraction of nanoparticles, the local Nusselt number

Abstract The effect of the temperature gradient on the Soret coefficient in n-pentane/n-decane (n-C5/n-C10) mixtures was investigated using non-equilibrium molecular dynamics (NEMD) with the heat exchange (eHEX) algorithm. n-Pentane/n-decane mixtures with three different compositions (0.25, 0.5, and 0.75 mole fractions, respectively) and the TraPPE-UA force field were used in computing the Soret coefficient

Journal Name: Journal of Non-Equilibrium Thermodynamics Volume: 45 Issue: 4 Pages: I-IV

Abstract In the kinetic rate laws of internal variables, it is usually assumed that the rates of internal variables depend on the conjugate forces of the internal variables and the state variables. The dependence on the conjugate force has been fully addressed around flow potential functions. The kinetic rate laws can be formulated with two potential functions, the free energy function and the flow

Abstract Phonon hydrodynamics uses the fields of the total energy and the heat flux as state variables. We extend it by promoting the microscopic internal energy field into the status of an extra independent state variable. The governing equations of both the phonon and the extended (two temperature) phonon hydrodynamics are formulated as particular realizations of the abstract GENERIC equation. Such

Abstract The question of frame-indifference of the thermomechanical models has to be addressed to deal correctly with the behavior of matter undergoing finite transformations. In this work, we propose to test a spacetime formalism to investigate the benefits of the covariance principle for application to covariant modeling and numerical simulations for finite transformations. Several models especially

Abstract Momentum and thermal transport through open-celled metallic foams filled in a channel of small height is studied in the present technical brief. Fully developed momentum and thermal layers via the Brinkman–Darcy model enable us to obtain closed-form solutions regarding the fluid velocity and temperature distributions of metal and fluid, all depending upon a factor related to the wall slip

Abstract We use the Shannon (information) entropy to define an “entropic” temperature for 1D nonequilibrium system with heat flux. In contrast to the kinetic temperature, which is related to the average kinetic energy, the nonequilibrium entropic temperature is related to the changes in entropy and serves as a criterion for thermalization. However, the direction and value of the heat flux is controlled

Abstract The aim of this paper is to analyze the behavior of oxytactic microorganisms and thermo-bioconvection nanofluid flow through a Riga plate with a Darcy–Brinkman–Forchheimer porous medium. The Riga plate is composed of electrodes and magnets that are placed on a plane. The fluid is electrically conducting, and the Lorentz force evolves exponentially along the vertical direction. The governing

Abstract The fundamental issue in the energetic performance of power plants, working both as traditional fuel engines and as combined-cycle turbines (gas-steam), lies in quantifying the internal irreversibilities which are associated with the working substance operating in cycles. The purpose of several irreversible energy converter models is to find objective thermodynamic functions that determine

Abstract Despite its idealizations, thermodynamics has proven its power as a predictive theory for practical applications. In particular, the Curzon–Ahlborn efficiency provides a benchmark for any real engine operating at maximal power. Here we further develop the analysis of endoreversible Otto engines. For a generic class of working mediums, whose internal energy is proportional to some power of

Journal Name: Journal of Non-Equilibrium Thermodynamics Volume: 45 Issue: 3 Pages: I-IV

Journal Name: Journal of Non-Equilibrium Thermodynamics Volume: 45 Issue: 2 Pages: I-IV

Abstract Thermodynamic performance analysis of microscopic Feynman’s engine has always been a hot topic, since it can reveal the operating mechanism of the system and give out the suggestions of performance improvement. The present work explores the optimal performance regions of the ratchet operating, respectively, as heat engine and refrigerator. The major purpose is to obtain the optimal performance

Abstract The main aim of this research work is to show the simultaneous effects of ferro-particles ( Fe 3 O 4 {\text{Fe}_{3}}{\text{O}_{4}}) and thermal radiation on the natural convection of non-Newtonian nanofluid flow between two vertical flat plates. The studied nanofluid is created by dispersing ferro-particles ( Fe 3 O 4 {\text{Fe}_{3}}{\text{O}_{4}}) in sodium alginate (SA), which is considered

Abstract This work proposes a structure synthesis and surface distribution algorithm in a heat exchange system for the case when all heat capacity rates and inlet temperatures of the hot streams are constant, while cold streams also have outlet temperatures set. The algorithm includes the possibility of changing the phase state of the contacting streams. The synthesis is based on minimization of dissipation

Abstract First, the special-relativistic Theory of Irreversible Processes for a multi-component fluid is formulated. It is based on (i) the balance equations of the particle number and the energy-momentum for the total system (i. e., the mixture of the components) as well as the sub-systems (i. e., the components) and (ii) the dissipation inequality and the Gibbs equation for the mixture. In order

Abstract Canonical statistical mechanics hinges on two quantities, i. e., state degeneracy and the Boltzmann factor, the latter of which usually dominates thermodynamic behaviors. A recently identified phenomenon (supradegeneracy) reverses this order of dominance and predicts effects for equilibrium that are normally associated with non-equilibrium, including population inversion and steady-state particle

Abstract In this study, the effect of magnetic field on an incompressible ferrofluid flow along a vertical wavy surface saturated in a porous medium is investigated. Ferrofluid is made by incorporating magnetic particles, in this case cobalt, at the nanoscale level into a base fluid. For the study of porous medium two well-known models, namely, Darcy and non-Darcy, are used. The mathematical model

Abstract The present mathematical simulation deals with the study of heat transfer characteristics of the shape of gold nanoparticles (Au-NPs) on blood flow past an exponentially stretching sheet using Sisko nanofluid taking into account the Biot number effect. Influences of non-linear thermal radiation and suction/injection are considered. The one-phase model is used to describe the Sisko nanofluid

Abstract In order to meet the current challenges in the fabrication of nanobiomaterials and enhancement of thermal extrusion systems, current theoretical continuation is targeted at the rheology of couple stress nanofluid by exploiting activation energy, porous media, thermal radiation, gyrotactic micro-organisms, and convective Nield boundary conditions. The heat and mass performances of nanofluid

Abstract In this work, the effect of temperature-dependent thermal conductivity ( k ( T )k(T)) and viscosity ( μ ( T )\mu (T)) variation on entropy generation in circular channels with an approach from macro- to micro-scale is numerically investigated. Thermally as well as hydrodynamically fully developed flow of water through the fixed length channels with constant total heat flow rate and total mass

Abstract A fugacity-based thermodynamic model for hydrate has been used to determine the equilibrium pressures of hydrate formation. This fugacity-based model uses the PRSV equation of state, which is used to represent the gas phases in the hydrate. The parameters of the model are fitted to the experimental data of binary guest hydrates. The present study is aimed at investigating binary mixtures of

Abstract Developing an effective model for non-equilibrium states is of great importance for a variety of problems related to chemical synthesis and combustion. Rate-Controlled Constrained-Equilibrium (RCCE), a model order reduction method that originated from the second law of thermodynamics, assumes that the non-equilibrium states of a system can be described by a sequence of constrained-equilibrium

Abstract Non-equilibrium thermodynamics provides a general framework for the description of mass and thermal diffusion, thereby including also cross-thermal and material diffusion effects, which are generally modeled through the Onsager coupling terms within the constitutive equations relating heat and mass flux to the gradients of temperature and chemical potential. These so-called Soret and Dufour

Abstract One of the recognized differences between normal and cancer cells is in their metabolic profile. Tumor cells tend to produce energy through glycolysis rather than the much more efficient oxidative phosphorylation pathway, which healthy cells generally prefer. This phenomenon is identified as the Warburg effect. Although several functional explanations have been proposed for the Warburg effect

Abstract The Stochastic Novikov engine is an endoreversible model for heat engines where the heat supply takes place at a fluctuating temperature. These fluctuations can be observed for example at solar thermal power plants. While recently the influence of the temperature fluctuations on the engine’s performance has been studied for Newtonian heat transport, the relation between the used heat transport

Abstract Thermal energy transfer in combined thin films consisting of silicon and diamond is considered. The combined films are thermally disturbed by a temperature oscillation at the silicon left edge and the influence of pulse length of temperature oscillation on energy transport characteristics is investigated. A nano-size gap with varying length is adopted at the films interface. The Boltzmann

Abstract The current work presents a concept that deals with the production of entropy generated by non-equilibrium processes in consequence of mass and energy transfer. The often used concept of endoreversible thermodynamics is based on the non-realistic conjecture that the entire entropy production is realized at the system boundary. In this contribution, an open system in a thermodynamically non-equilibrium

Abstract The main purpose of this numerical investigation is to estimate energetically the thermo-magnetohydrodynamic (MHD) irreversibility arising in Stokes’ second problem by successfully applying the first and second thermodynamic laws to the unsteady MHD free convection flow of an electrically conducting dissipative fluid. This fluid flow is assumed to originate periodically in time over a vertical

Abstract A novel realistic Work Criteria Function (WCF) approach has been used to analyze the ideal air-standard Diesel cycle. The WCF formulation gives rise to a new performance criterion which is termed as efficient power density (EPD). Thermodynamic analysis under maximum efficient power density (MEPD) conditions has been performed and compared with other available performance criteria using variable

Abstract The present work models MHD three-dimensional flow in a rotating channel. The energy expression is characterized by heat generation/absorption and radiation effects. Homogeneous-heterogeneous features are also accounted for. The obtained non-dimensional systems are numerically computed via the NDSolve based Shooting technique. Graphs are plotted to visualize the impact of various influential

Abstract Measurements of Thomson (later Lord Kelvin) coefficients are made in an evacuated region on a silver sample with a novel transducer in temperature intervals T A ± 20 K{T_{A}}\pm 20\hspace{0.1667em}\text{K}, where the T A {T_{A}} are very carefully controlled ambient temperatures. This is the first systematic examination of Thomson coefficients in these temperature intervals. The Thomson coefficients

Abstract Entropy fluctuations with time occur in finite-sized time-evolving dissipative systems. There is a need to comprehend the role of these fluctuations on the fluctuations-averaged entropy generation rate, over a large enough observation time interval. In this non-equilibrium thermodynamic investigation, the Fluctuation Theorem (FT) and Principle of Least Action are re-visited to articulate their

Abstract Through altering the ambient environment of the iron conductor with respect to the copper conductor of an iron-copper thermocouple, the output emf of the thermocouple was reduced by a factor of almost two. This reduction was apparently a result of a Benedicks emf. Such a Benedicks emf was produced here in a continuous iron conductor. The Benedicks emf produced was about half the expected Seebeck

Last year, 63 participants from 18 countries gathered for the 8th edition of the International Workshop on Non-Equilibrium Thermodynamics IWNET (see http://www.nonequilibrium-thermodynamics.org for more details), which was organized by Markus Hütter (Eindhoven University of Technology) and Leonard Sagis (Wageningen University and Research) and was held in Sint-Michielsgestel, close to the city of ‘s

Abstract In this work, a novel hybrid model was developed in order to study the membrane-based liquid separation process. The membrane system was a continuous hollow-fiber membrane module for contacting two aqueous and organic phases for reactive extraction of benzoic acid (BA) from aqueous solution. Two simulation approaches were utilized in order to build a robust hybrid model. The hybrid model is