Mitochondria are central hubs of cellular bioenergetics, converting chemical free energy into ATP while inevitably releasing heat during respiration. Fluorescence-based thermometry has been interpreted to show intracellular "hot spots" more than 10 °C above the bulk physiological temperature, implying that mitochondria might operate far outside conventional thermal bounds. Such claims, however, appear inconsistent with basic biophysics: the small size of mitochondria, their aqueous and highly conductive environment, and their limited power output all argue against large steady-state temperature gradients. This discrepancy has prompted renewed scrutiny of both the physical limits of intracellular heat transfer and the biological interpretation of nanoscale thermal measurements. A key open question is whether nonequilibrium biochemical processes, such as respiration-driven proton pumping, could act as nanoscale heat pumps that maintain higher local temperatures than allowed by passive diffusion alone. Here, we develop a model-independent thermodynamic analysis based solely on the Second Law of Thermodynamics to bound the maximal temperature difference that any biochemically driven mechanism can sustain across the inner mitochondrial membrane and show that even under idealized conditions the achievable temperature rise is restricted to a small fraction of a degree, effectively closing this loophole.

Corrosion is a naturally occurring electrochemical degradation process that imposes severe economic and safety burdens on modern society by reducing the service life of metallic infrastructures in transportation, marine systems, electronics, and energy industries. From a fundamental standpoint, corrosion represents a spontaneous chemical reaction governed by thermodynamic feasibility and electrochemical kinetics, where the driving force is often explained through the Second Law of Thermodynamics and the relative stability of oxidation states in aqueous environments. Accordingly, standard reduction potentials provide an effective framework for predicting the tendency of metallic dissolution and cathodic reduction reactions under practical conditions. This review summarizes the fundamental principles of corrosion, including major corrosion forms such as uniform corrosion, galvanic corrosion, pitting, crevice corrosion, intergranular corrosion, and stress corrosion cracking. A critical discussion is presented on conventional corrosion mitigation strategies, including inhibitors, cathodic protection, alloying, surface passivation, and protective coatings. Particular emphasis is placed on graphene as an emerging corrosion-resistant material due to its high chemical stability, mechanical strength, and exceptional impermeability to aggressive species. The role of graphene as a diffusion barrier is analyzed in terms of defect density, interfacial adhesion, and microstructural integrity. Furthermore, recent progress in nickel–graphene composite coatings is reviewed, highlighting their improved barrier properties, grain refinement effects, enhanced polarization resistance, and suppression of localized corrosion processes. Finally, current challenges and future research directions are outlined, focusing on scalable fabrication, dispersion stability, long-term durability, and the development of multifunctional graphene-enabled anticorrosion coatings for industrial deployment.

As a member of modified theories of gravity, f(R) theories of gravity offer a compelling explanation for the observed phenomenon of the late-time cosmic acceleration, which is a puzzle that general relativity cannot solve. Moreover, it has been proved that the field equations of f(R) theories of gravity are equivalent to the first law of thermodynamics. This equivalence holds true even in the presence of matter-geometry coupling. As more and more f(R) gravitational models are proposed, it is crucial to investigate their physical validity. In this paper, three different f(R) gravitational models with arbitrary coupling between matter and geometry are investigated by the generalized second law of thermodynamics on cosmological scales with astronomical observational data. The results show that all the models considered in this work not only satisfy the generalized second law of thermodynamics but also account for the late-time cosmic acceleration. Moreover, the cosmic matter candidate in the models under consideration is radiation, ordinary matter, vacuum energy, quintessence-like fields or phantom-like fields.

The maximum efficiency of extracting work from thermal radiation energy has been intensely studied. However, a large part of the world's energy resources is actually used for heating rather than work production. Therefore, finding the most effective way of heating by using radiation energy is another problem of great practical interest, not often studied. Here, it is demonstrated that such a way involves heat extractors. A general broadband theory based on the first and second laws of thermodynamics and the model of deformed blackbody radiation is developed for radiation-driven heating systems. Particular cases are considered under the assumption of local thermal equilibrium. Application to solar radiation heating shows that the photothermal heating efficiency may be improved. During a winter clear sky day, solar radiation-driven heat extractors may provide, in the ideal case, several times more heat per unit collection surface area than traditional solar heating. When constructed with current technology, heat extractors with evacuated tube solar collectors oriented toward the Sun under low-concentrated radiation may provide between 106% and 118% more heat per unit collection surface area than traditional solar heating. For an improved (mature) heat extractor technology, this range of values increases to about 130% to 337%, depending on ambient temperature. This makes the problem of radiation heating efficiency important from a practical point of view.

We study liquid crystal models with bulk free energy from the point of view of the second law of thermodynamics. We formulate these models as objective internal variable models. Examples of application are given for the de Gennes free energy.

Abstract This paper studies the impact of bulk viscosity on the feasibility of the cosmological bounce solutions in the framework of F ( R ) theory. In this perspective, the behavior of an isotropic homogeneous universe with a perfect matter configuration and new formulation of the bulk viscosity coefficient is explored. We select a specific mathematical form of the modified gravity model to see how it affects the dynamics of cosmic evolution. In addition, we analyze various cosmological parameters, exploring the presence of feasible cosmological bounce solutions. A physically acceptable bouncing scenario occurs when the energy density stays positive, pressure becomes negative, and the violation of null and strong energy conditions highlight the important role of bulk viscosity. We also study the cosmographic parameters and their paths in the $$r-s$$ r - s diagnostic framework. Finally, a thermodynamic investigation is carried out to test the generalized second law of thermodynamics and the overall stability of the cosmological model. The results show that F ( R ) gravity is a realistic and promising alternative to the standard cosmological model, giving deeper understanding of gravitational dynamics and the early evolution of cosmos.

The study is based on the first and second laws of thermodynamics to investigate and analyze the performance of spark ignition engines with varying injection durations of the gasoline and bioethanol fuel blend (E50). Experiments were conducted using standard parameters of engines, including an 11:1 compression ratio and 12 bTDC of ignition timing. The injection volume of the fuel blend was set at 100% to 200% (increment of 25%) of the injection volume of gasoline. The effect of the injection volume of E50 is evident in various performance indicators, including brake-specific fuel consumption (BSFC), thermal efficiency, and brake power, as observed in both energy and exergy analyses. The most important conclusion of this study is that the performance of the engine using E50 would be similar to gasoline (E0), both in energy and exergy analyses, when the injection volume of E50 increased by 25% compared to gasoline.

In this work, we investigate the compatibility with the second law of thermodynamics of certain evolution equations for heat flux which frequently appear in the literature when treating problems of extended thermodynamics, namely in dual-phase-lag (DPL) and in three-phase-lag (TPL) theories for a rigid thermal conductor. For each one of these two cases, we propose a concrete form for the free energy function, in which heat flux enters as an independent variable side by side with temperature, and a corresponding non-negative quadratic dissipation function. An important aspect of the present work is that all the introduced material tensors in the formulation of the free energy are kept to the simplest form possible, and can be calculated based on experimental data. The present results demonstrate that both DPL and TPL approximate models for the evolution equation of the heat flux considered here can be rendered thermodynamically admissible through a class of free energy functions to satisfy the Second Law, providing a flexible and consistent modeling of non-Fourier heat conduction. In any case, it is shown that temperature and heat flux are determined simultaneously from a set of coupled, nonlinear partial differential equations, and that obtaining an equation for temperature independently from heat flux could be achieved only in special cases and under some simplifying assumptions. Within this context, the heat conductivity is assumed a linear function of temperature, an essential feature from an experimental point of view. The used methodology, consisting of going from evolution equations for the heat flux to the construction of dissipation functions and free energies which satisfy the requirements of the second law, is, in our belief, a useful trend to treat more difficult cases for higher approximation theories, or for couplings with the other fields, i.e. dynamics, electromagnetism and other. In spite of slight resemblance with published work, the suggested concrete forms of the free energies and dissipation functions, as well as the governing nonlinear set of partial differential equations are not mentioned in the available literature to the authors knowledge. It turns out that the only requirement of consistency with the second law of thermodynamics for the treated cases is that the thermal relaxation times be non-negative, and that the thermal relaxation time related to thermal displacement in TPL satisfies a certain inequality. Any further requirements could be linked only to the stability of solutions of the arising governing partial differential equations. A one-dimensional application in a half-space solves the newly suggested nonlinear system of governing equations, giving a physical insight to the presented model, and pointing out at its adequacy for describing the propagation of thermal waves with finite speed.

Electrohydrodynamic (EHD) drying is a novel drying technology with extremely low energy consumption. To understand the reason for energy-efficient drying, energy and exergy flows in the thermodynamic system were studied. The thermodynamic study revealed that drying efficiency is dependent on the air temperature. Energy analysis was conducted using the First Law, while exergy was evaluated based on the Second Law of thermodynamics. The drying efficiency was characterized by energy and exergy consumption in Joules per gram of evaporated water. From exergy analysis and experiments, we concluded that water evaporation in EHD drying is primarily driven by scavenging of thermal energy from the ambient environment. A comparative analysis showed the advantages of EHD compared to other sustainable drying technologies based on renewable energy sources.

We present a general framework for deriving entropy production rates in active matter systems driven by non-Gaussian active fluctuations. Employing the probability-flow equivalence technique, we rigorously obtain an entropy production (EP) decomposition formula. We demonstrate that the EP, Δs_{tot}, satisfies a detailed fluctuation theorem, ρ_{R}(Σ)/ρ_{R}(-Σ)=e^{Σ}, which holds for the distribution ρ_{R}(Σ) defined as the probability of observing a value Σ of the quantity R≡Δs_{tot}-B_{act}, where B_{act} is a path-dependent random variable associated with active fluctuations. Moreover, an integral fluctuation theorem, ⟨e^{-R}⟩=1, and the generalized second law of thermodynamics, ⟨Δs_{tot}⟩≥⟨B_{act}⟩, follow directly. Our results hold under steady-state conditions and can be straightforwardly extended to arbitrary initial states. In the limiting case where active fluctuations vanish, these theorems reduce to the established results of stochastic thermodynamics. Building on this theoretical foundation, we introduce a deep-learning-based methodology for efficiently computing the EP, utilizing the Lévy score we propose. To illustrate the validity of our approach, we apply it to two representative systems: a Brownian particle in a periodic active bath and an active polymer composed of an active Brownian cross-linker interacting with passive Brownian beads. Our Letter provides a unified framework for analyzing EP in active matter and offers practical computational tools for investigating complex nonequilibrium behavior.

This is a transcript of the presentation given at the symposium celebrating Swapan Chattopadhyay’s retirement held via Zoom on April 30, 2021. Beginning with a demonstration of the Maxwell’s demon paradox, I show its similarity to Simon van der Meer’s stochastic cooling method and briefly follow the evolution of ideas for demon exorcism. I review Rolf Landauer’s principle governing the thermodynamics of information and its refinement by Charles Bennett widely used to vindicate the second law of thermodynamics. After that, I present the idea for a stochastic cooling of electrons and positrons without the amplifier and without the need to gather, process and act on the information about the system by the external observer. Finally, I show that quantum mechanics plays an essential role in this cooling process and thus keeps the Maxwell’s demon at bay. I was inspired to come up with this story by Swapan Chattopadhyay, who suggested the title for my presentation.

This article reconceptualizes entropy not as a metaphysical substance but as a structural constraint that shapes the formation, energetic cost, and durability of records. It links the coarse-grained—and typically irreversible—flow of time to questions of moral responsibility and divine justice. Drawing on the second law of thermodynamics, information theory, and contemporary cosmology, it advances an analogical and operational framework in which actions are accountable in an analogical sense insofar as they leave energetically costly traces that resist erasure. Within a Qur’ānic metaphysical horizon, concepts such as kitāb (Book), ṣaḥīfa (Record), and tawba (Repentance) function as structural counterparts to informational inscription and revision, without reducing theological meaning to physical process. In contrast to Kantian ethics, which grounds moral law in rational autonomy, the Qurʾān situates responsibility within the irreversible structure of time. Understood in this way, entropy is not a threat to coherence but a condition for accountability. By placing the Qurʾānic vision in dialog with modern science and theology, the article contributes to broader discussions on justice, agency, and the metaphysics of time within the science–religion discourse.

Based on micropolar theory, we develop a novel mathematical framework for modeling finite elastoplastic deformations. The proposed formulation accommodates both large strains and finite rotations while exploiting the ability of micropolar theory to represent underlying material microstructure. The balance equations are obtained from an invariance principle with respect to general observer transformations. Within the setting of material uniformity, the plastic evolution laws are expressed as first-order differential equations for a set of material transplants, subject to the formal restrictions dictated by micropolar material symmetries and the constraints of the second law of thermodynamics. In addition, we identify the micropolar Mandel stress tensors as the energetic driving forces governing the local rearrangement of material inhomogeneities.

ABSTRACT In this paper, we focus on numerical modeling of coupled processes of heat transfer and two‐phase flow in porous media, which play a crucial role in many fields, particularly in thermally enhanced oil recovery and geothermal production. We first introduce a thermodynamically consistent numerical modeling framework for non‐isothermal incompressible immiscible two‐phase flow in porous media, which integrates the energy conservation equation with the newly developed two‐phase flow equations. Applying the Gibbs fundamental relation, we rigorously derive an entropy equation, which demonstrates that the model obeys the second law of thermodynamics. To resolve numerical challenging aspects resulting from the inherent nonlinearity and strong coupling of the model, we apply subtle implicit and explicit mixed treatments and the energy factorization approach, in order to design a linearized and decoupled time marching scheme. The spatial discretization is constructed using the cell‐centered finite volume method with carefully designed treatments. In particular, the averaging and upwind strategies are applied for discretizing the energy conservation equation to enforce the local energy conservation and the entropy stability (i.e., the adherence to the second law of thermodynamics). Taking advantage of the discrete versions of the Gibbs relation and the specific mean and difference splitting rules, we derive a discrete counterpart of the second law of thermodynamics, which yields the entropy stability without any restriction on time step sizes. Numerical experiments are performed to demonstrate the features and capabilities of the proposed scheme.

This paper proposes a change in the traditional epistemological paradigm and a look at classical thermodynamics from the point of view of control theory, with the aim of discovering energy state variables. The paper proposes a transition from “causality” to “purposefulness” in nature, which is called port-Hamiltonian thermodynamics. It is unclear whether classical thermodynamics can be incorporated into the formalism of port-Hamiltonian field theory, and it is likely that thermodynamics will need to be expanded or even completely reformulated. The main goal is to satisfy the First and Second Laws of Thermodynamics a priori.

A bstract In this work, we attempt to construct bit thread configurations for various backgrounds using expressions from the covariant phase space formalism. We find that when the Ryu-Takayanagi surface is same as the horizon, such expressions are sufficient. In other cases, it differs by gradient of a harmonic function. We explore its relation to Wald and differential entropy, and re-express the first law of entanglement entropy in terms of bit threads. Inclusion of quantum effects imposes some constraints on the bulk entanglement via the dominant energy condition. We also apply our method to ascertain a bit thread configuration in a certain dynamical spacetime.

In this paper, we obtain logarithmic corrections to the black hole entropy. Motivated by our recent proposal concerning the nature of the degrees of freedom leading to the black hole entropy in terms of a Bose–Einstein (BEC) condensate of gravitons, we study how to introduce logarithmic corrections. In fact, we show that after modifying the internal energy by means of simple by physically sound arguments dictated by ordinary quantum mechanics and possible noncommutative effects at Planckian scales, a logarithmic term does appear in the Bekenstein–Hawking entropy law. We also obtain that the entropy [Formula: see text] of a ball of Planckian areal radius is [Formula: see text], i.e. [Formula: see text]. Our approach shows that the possibility that the interior of a black hole is composed with a BEC of gravitons is a viable physically motivated possibility.

Modeling and numerical simulation of coupled poromechanical problems with multicomponent compressible flow are of particular importance in many fields including shale and natural gas engineering, carbon dioxide sequestration and geotechnical engineering. In this paper, using the second law of thermodynamics, we rigorously derive a thermodynamically consistent model for multicomponent compressible flow in deformable porous media coupled with poroelasticity. The model herein takes molar densities as the primary unknowns rather than pressure and molar fractions as well as introduces fluid and solid free energies, so that it naturally follows an energy dissipation law. Additionally, the Maxwell-Stefan model of multicomponent diffusion is generalized as a multicomponent fluid-solid coupling model accounting for the solid deformation, which not only satisfies Onsager’s reciprocal principle but also yields a thermodynamically consistent poro-visco-elastic equation. For numerical simulation, we propose a novel energy stable and mass conservative numerical scheme for the model. We first design the semi discrete time scheme using the stabilized energy factorization approach to deal with the multicomponent Helmholtz free energy as well as subtle semi-implicit treatments for the coupling between multicomponent fluids and solids. A nontrivial treatment is the use of the discrete Gibbs Duhem equation substituting for the pressure gradient contributed by the multicomponent fluids in the solid mechanical balance equation, which establishes the thermodynamically consistent relation between fluids and solids at the discrete level. Based on the cell-centered finite volume method on staggered grids, the fully discrete scheme is constructed using the upwind strategy for both molar densities and porosity. The scheme is proved to preserve the discrete energy dissipation law and Onsager’s reciprocal principle as well as to conserve the mass of fluid components and solids. Numerical experiments are performed to confirm our theories, especially to demonstrate the good performance of the proposed scheme in energy stability and mass conservation as expected from our theoretical analysis.

Abstract Data are used from distinct sources like Dark Energy Survey five‐year supernovae data (DES 5YR), patterns in galaxy distributions (BAO), and the rate at which the universe is expanding over time (OHD) to study the so‐called Myrzakulov gravity (MG‐I). This theory is a modified version of gravity that utilizes a special kind of connection to describe how space and time behave, including some additional features not found in Einstein's theory of general relativity. In this model, pressureless matter is considered to discuss the physical features of the model, which include a thermodynamic analysis. The model is interpreted to be in good agreement with the recent observational datasets. The model presents a continuous transition from a decelerating to an accelerating state at the low redshift. Additionally, the model is consistent with at the early as well as final stages of the evolution of the Universe for joint datasets. The model exhibits Quintessence‐like behavior in redshift and converges to at the late times as for all observations. The development of the total entropy, Hawking temperature, and the viability of the second law of thermodynamics are explored in the model according to the recent observational dataset.

Neo-Gibbsian statistical energetics with applications to nonequilibrium cells.