Thermodynamic Relations Research Articles

Exact time-dependent thermodynamic relations for a Brownian particle moving in a ratchet potential coupled with quadratically decreasing temperature

Exact time-dependent thermodynamic relations for a Brownian particle moving in a ratchet potential coupled with quadratically decreasing temperature

Numerical simulation of phase transition with the hyperbolic Godunov-Peshkov-Romenski model

In this paper, a thermodynamically consistent numerical solution of the interfacial Riemann problem for the first-order hyperbolic continuum model of Godunov, Peshkov and Romenski (GPR model) is presented. In the presence of phase transition, interfacial physics are governed by molecular interaction on a microscopic scale, beyond the scope of the macroscopic continuum model in the bulk phases. The developed approximate two-phase Riemann solvers tackle this multi-scale problem, by incorporating a local thermodynamic model to predict the interfacial entropy production. Using phenomenological relations of non-equilibrium thermodynamics, interfacial mass and heat fluxes are derived from the entropy production and provide closure at the phase boundary. We employ the proposed Riemann solvers in an efficient sharp interface level-set Ghost-Fluid framework to provide coupling conditions at phase interfaces under phase transition. As a single-phase benchmark, a Rayleigh-Bénard convection is studied to compare the hyperbolic thermal relaxation formulation of the GPR model against the hyperbolic-parabolic Euler-Fourier system. The novel interfacial Riemann solvers are validated against molecular dynamics simulations of evaporating shock tubes with the Lennard-Jones shifted and truncated potential. On a macroscopic scale, evaporating shock tubes are computed for the material n-Dodecane and compared against Euler-Fourier results. Finally, the efficiency and robustness of the scheme is demonstrated with shock-droplet interaction simulations that involve both phase transfer and surface tension, while featuring severe interface deformations.

A Hollow Hemispherical Mixed Matrix Lithium Adsorbent with High Interfacial Interaction for Lithium Recovery from Brine

Mixed matrix lithium adsorbents have attracted much interest for lithium recovery from brine. However, the absence of an interfacial interaction between the inorganic lithium-ion sieves (LISs) and the organic polymer matrix resulted in the poor structural stability and attenuated lithium adsorption efficiency. Here, a novel hollow hemispherical mixed matrix lithium adsorbent (H-LIS) with high interfacial compatibility was constructed based on mussel-bioinspired surface chemistry using a solvent evaporation induced phase transition method. The effects of types of functional modifiers, LIS loading amount, adsorption temperature and pH on their structural stability and lithium adsorption performance were systematically investigated. The optimized H-LIS adsorbent with the LIS loading amount of 50 wt.% possessed the structural merit that the LIS functionally modified by dopamine exposed on both the inner and outer surfaces of the hollow hemispheres. At the best adsorption pH of 12.0, it showed a comparable lithium adsorption capacity of 25.68 mg·g−1 to the powdery LIS within 4 h, favorable adsorption selectivity of Mg/Li and good reusability that could maintain over 90% of lithium adsorption capacity after the LiCl adsorption—0.25 M HCl pickling-DI water cleaning cycling processes for three times. The interfacial interaction mechanism of H-LIS for lithium adsorption was innovatively explored via advanced microcalorimetry technology. It suggested the nature of the Li+ adsorption process was exothermic and dopamine modification could reduce the activation energy for lithium adsorption from 15.68 kJ·mol−1 to 13.83 kJ·mol−1 and trigger a faster response to Li+ by strengthening the Li+-H+ exchange rate, which established the thermodynamic relationship between the structure and Li+ adsorption performance of H-LIS. This work will provide a technical support for the structural regulation of functional materials for lithium extraction from brine.

Thermodynamics-consistent graph neural networks.

We propose excess Gibbs free energy graph neural networks (GE-GNNs) for predicting composition-dependent activity coefficients of binary mixtures. The GE-GNN architecture ensures thermodynamic consistency by predicting the molar excess Gibbs free energy and using thermodynamic relations to obtain activity coefficients. As these are differential, automatic differentiation is applied to learn the activity coefficients in an end-to-end manner. Since the architecture is based on fundamental thermodynamics, we do not require additional loss terms to learn thermodynamic consistency. As the output is a fundamental property, we neither impose thermodynamic modeling limitations and assumptions. We demonstrate high accuracy and thermodynamic consistency of the activity coefficient predictions.

Elastic properties and thermodynamic anomalies of supersolids

We study a supersolid in the context of a Gross-Pitaevskii theory with a nonlocal effective potential. We employ a homogenization technique which allows us to calculate the elastic moduli, supersolid fraction, and other state variables of the system. Our methodology is verified against numerical simulations of elastic deformations. We can also verify that the long-wavelength Goldstone modes that emerge from this technique agree with Bogoliubov theory. We find a thermodynamic anomaly that the supersolid does not obey the thermodynamic relation ∂P/∂V|N=−n(∂P/∂N|V), which we claim is a feature unique to supersolids. Published by the American Physical Society 2024

Thermodynamic inference of correlations in nonequilibrium collective dynamics

The theory of stochastic thermodynamics has revealed many useful fluctuation relations, with the thermodynamic uncertainty relation (TUR) being a theorem of major interest. When many nonequilibrium currents interact with each other, a naive application of the TUR to an individual current can result in an apparent violation of the TUR bound. Here, we explore how such an apparent violation can be used to put a lower bound on the strength of correlations C as well as the number N of interacting currents in collective dynamics. This lower bound is a combined bound on C(N−1) if only one current is measured, or a bound on N if two currents are measured. Our proposed protocol allows for the inference of hidden correlations in experiment, for example when a team of molecular motors pulls on the same cargo but only one or a subset of them is fluorescently tagged. By solving analytically and numerically several models of many-body nonequilibrium dynamics, we ascertain under which conditions this strategy can be applied and the inferred bound on correlations becomes tight. Published by the American Physical Society 2024

A staggered Lagrangian magnetohydrodynamics method based on subcell Riemann solver

This paper uses a general formalism to derive staggered Lagrangian method for 2D compressible magnetohydrodynamics (MHD) flows. A subcell method is introduced to discretize the MHD system and some Riemann problems over subcells are solved at the cell center and grid node respectively. In these solvers, only the fast-waves in all jumping relations are considered and thus the solution structure is simple. The discrete conservations of mass, momentum and energy are preserved naturally in the proposed numerical method. In order to meet the thermodynamic Gibbs relation in isentropic flows, an adaptive Riemann solver is implemented at the cell center, in which a criterion is proposed to reduce overheating errors in the rarefying problems and maintains the excellent shock-capturing ability simultaneously. It is worth to be noticed that the divergence-free condition is naturally satisfied in the Lagrangian method. Various numerical tests are presented to demonstrate the accuracy and robustness of the algorithm.

Predictive potentialities of the Quasi-Random Lattice model for electrolyte solutions, discussion and improvement strategies

This article focuses on the predictive potentialities of the Quasi-Random Lattice (QRL) model, developed for describing the activity behaviour of electrolytic solutions, and elaborates strategies for their improvement.First, the study critically discusses the computational-experimental procedure (previously published) for determining the QRL parameterization, whose convergence within few iterations is counterbalanced by known experimental issues concerning, in particular, the mean activity coefficient. An alternative procedure is proposed, that makes use of osmotic data at medium-high concentrations, so as to make QRL more interesting from a practical point of view.Second, the study explores the applicability of the model beyond the concentration ranges earlier considered. To this purpose, the solution density is evaluated in detail. Its thermodynamic relationship with the mean activity coefficient yields a parametric Abel Equation of the Second Kind valid in the medium-high range of concentrations. A further density equation is formulated, useful in the low-medium range, based on a classical power-series combined with appropriate analytical constraints to improve estimation and prediction methods.QRL theory, methods and procedures are applied to binary aqueous solutions at 25°C.

Traces of Quantum Gravity Effects at Late-time Cosmological Dynamics via Distance Measures

Inspired by the entropy–area relation of black hole thermodynamics, we study the thermodynamics of the cosmological apparent horizon in a spatially flat Friedmann–Robertson–Walker universe in the framework of an extended uncertainty principle (EUP). The adopted EUP naturally admits a minimal measurable momentum (equivalently a maximal measurable length), as an infrared cutoff in the theory. We derive the modified Friedmann equations in this setup and explore some predictions of these equations for the late-time universe via distance measures. We show that in this framework it is possible to realize the late-time cosmic speedup and transition to the phantom phase of the equation-of-state parameter of the effective cosmic fluid without recourse to any dark energy component or modified gravity. Inspection of various distance measures in this framework shows that an EUP with a negative deformation parameter suffices for the interpretation of the late-time asymptotically de Sitter universe with standard nonrelativistic matter.

Network analysis for the steady-state thermodynamic uncertainty relation

Network analysis for the steady-state thermodynamic uncertainty relation

Analysis of flow boiling incipience models in computational fluid dynamics

Recent advances in the computational fluid dynamics and heat transfer (CFD/HT) modeling of flow boiling have enabled a more detailed analysis and understanding of thermal management in relatively complex microsystems. Most advanced modeling approaches allow the transient analysis of two-phase flow and phase-change processes, providing the capability to post-process in detail the temperature, phase and pressure distributions in microscale applications with the use of moderate computational resources. Although these models have significantly evolved in recent years, there are still several idealizations and assumptions that have yet to be improved or better justified, the boiling incipience treatment being a commonly questioned topic. In the present investigation, a boiling incipience model is incorporated into an existing CFD/HT model for the analysis of flow boiling mechanisms, where the superheat temperature is derived from fundamental thermodynamic relations and compared to the original CFD/HT model that does not account for such effects. Results are compared using a non-trivial case of a silicon micro-cooling layer with variable density of pin fins that has been demonstrated to be an efficient thermal control device in high-power applications. The dielectric fluid HFE-7200 is used as the coolant in flow boiling conditions. The two-phase flow regimes and heat transfer results for both models are compared.

Tradeoff relations in open quantum dynamics via Robertson, Maccone–Pati, and Robertson–Schrödinger uncertainty relations

Abstract The Heisenberg uncertainty relation, together with Robertson’s generalisation, serves as a fundamental concept in quantum mechanics, showing that noncommutative pairs of observables cannot be measured precisely. In this study, we explore the Robertson-type uncertainty relations to demonstrate their effectiveness in establishing a series of thermodynamic uncertainty relations and quantum speed limits in open quantum dynamics. The derivation utilises a scaled continuous matrix product state representation that maps the time evolution of the quantum continuous measurement to the time evolution of the system and field. Specifically, we consider the Maccone–Pati uncertainty relation, a refinement of the Robertson uncertainty relation, to derive thermodynamic uncertainty relations and quantum speed limits. These newly derived relations, which use a state orthogonal to the initial state, yield bounds that are tighter than previously known bounds. Moreover, we consider the Robertson–Schrödinger uncertainty, which extends the Robertson uncertainty relation. Our findings not only reinforce the significance of the Robertson-type uncertainty relations, but also expand its applicability in identifying uncertainty relations in open quantum dynamics.

Thermodynamic relation of accelerating black holes in anti-de Sitter spacetime

We consider accelerating black holes in four-dimensional anti-de Sitter spacetime and investigate the extremality relations by examining perturbative corrections to both the entropy of black holes and their extremality bounds. It is shown that the so-called Goon and Penco (univeral) relation is also valid for accelerating black holes. Furthermore, it is found that an appropriate matching condition is necessary between the perturbation parameter of the relation with the perturbative correction to such black holes, and the parameter with information about the conical deficits on the north and south poles with the cosmic string tensions in order to satisfy the extremality relations. This result indicates that the extremality (univeral) relation of a class of accelerating black holes holds exhibit behavior similar to the Weak Gravity Conjecture.

Integrated structural and functional analysis of Ba1-xSrxTiO3-Bi0.5Na0.5TiO3 ceramics: Insights into energy storage and electrocaloric performance

This paper reports an extensive investigation on the structural, dielectric, ferroelectric and pyroelectric properties of 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 (x = 0.0, 0.5, 0.6, 0.7) ceramics synthesized via conventional solid-state reaction (SSR) technique. X-ray diffraction data confirms the presence of pure perovskite phase. The variation of lattice parameters with strontium concentration in 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 ceramics were evaluated using the Rietveld refinement of the XRD data. The variation of dielectric permittivity with temperature (ε' ∼ T) shows the diffused phase transition and all the parameters related to the relaxor ferroelectrics (relaxation coefficient, activation energy and freezing temperature) were evaluated. The energy storage properties of the as-prepared ceramics were evaluated using the room temperature PE loop. Amongst the as-prepared ceramics, the composition with x = 0.5 possesses the highest energy storage density of 0.46 J/cm3 with an efficiency of 90 %. The temperature dependent P-E loops were used to study the electrocaloric effect (ECE). The ECE calculations were performed using in-direct method based on Maxwell's thermodynamic relations. A maximum adiabatic temperature change of 0.32 K is achieved at 268 K under a small applied electric field of 25 kV/cm for the ceramic with Sr content x = 0.5. Additionally, electrocaloric responsivity ξmax = 0.13 K mm/kV was also found for the studied ceramics. The above results show that the ceramic 0.7Ba1-xSrxTiO3 – 0.3Bi0.5Na0.5TiO3 with the composition x = 0.5 is a viable lead-free option for application in solid state refrigeration.

Dyeing kinetics and thermodynamics of mono-chlorotriazine reactive dye in recycled wastewater

Purpose This study aims to elucidate the dyeing kinetics and thermodynamic relationships of CI Reactive Red 24 (RR24) on cotton fabrics, achieve the recycling of inorganic salts and water resources and obtain comprehensive data on color parameters, fastness and other characteristics of fabrics dyed with the recycled dyeing residual wastewater. Design/methodology/approach The dyeing wastewater obtained through advanced oxidation technology was used as a medium for dyeing cotton fabrics with RR24. The absorbance value of the dyeing residue served as an evaluation index, and the relevant kinetic and thermodynamic parameters were calculated based on this absorbance. The color parameters and fastness of the fabric samples were measured to compare the performance of different dyeing media. Findings Dyeing cotton with RR24 in both media follows pseudo-second-order kinetics. When dyeing with wastewater media, the dye adsorption in the first 45 min increased by 0.082–1.29 g/kg compared with conventional dyeing. Furthermore, the half-dyeing time was shortened by 4.19–11.99 min and the equilibrium adsorption amount was reduced by 0.277–0.302 g/kg. The adsorption of RR24 on cotton fabrics conformed to the Freundlich model. Fabrics dyed using recycled wastewater exhibit a deeper color, with reduced red light and enhanced blue light, resulting in an overall deeper apparent color. Originality/value These dyeing kinetics and thermodynamic properties are beneficial for comprehending and interpreting the dyeing performance and behavior of reactive dyes in dyeing wastewater. They lay a theoretical foundation for the treatment and recycling of dyeing wastewater.

Modeling Study of Enhanced Coal Seam Gas Extraction via N2 Injection Under Thermal-Hydraulic-Mechanical Interactions.

N2 injection into coal seams can effectively enhance the gas flow capacity in the late stage of pumping, thereby improving the recovery rate and recovery efficiency of low coalbed methane (CBM). To reveal the thermodynamic flow coupling relationship between the reservoir and the gas phase and its transportation mechanism in the process of thermal N2 injection, a mathematical coupling model of N2 injection that considers the deformation of the coal seam, fluid transportation, and temperature change was established. The influence of the seepage heat transfer effect of the coal seam under the effect of N2 injection on the CH4 extraction rate was investigated using this model. Results indicate that the action mechanism of N2 injection in coal seams includes increasing seepage, promoting flow, and displacing gases. A higher initial coal seam temperature results in a smaller thermal expansion and deformation of the coal skeleton during thermal N2 injection and less pronounced coal permeability increase. A larger initial coal seam permeability results in more favorable N2 diffusion, which strengthens the flow-promoting effect on CH4. The effect of gas injection pressure on CH4 recovery is greater than that of the gas injection temperature: High pressure promotes N2 seepage, carries CH4 flow, and increases the CH4 diffusion effect, whereas higher temperature promotes the desorption of adsorbed gas in the coal seam and improves the recovery rate.

Synchronization-induced violation of thermodynamic uncertainty relations

Synchronization-induced violation of thermodynamic uncertainty relations

Hesperetin–4,4′-bipyridine cocrystal: Polymorphism, crystal structures, and thermodynamic relationship

The investigation of cocrystal polymorphism remains relatively limited compared to that of single-component crystals. This study focuses on the cocrystallization of hesperetin (HES), a typical flavonoid substance, with 4,4′-bipyridine (BPY), resulting in the formation of two distinct 1:1 cocrystal phases. Single crystal X-ray diffraction analysis reveals that the O—H···N hydrogen interaction serves as the hetero-synthon of the cocrystals, driving the formation of featured 1D molecular chains in both structures. The presence of rotatable C—C bonds in both HES and BPY introduces the possibility of the molecular conformational variations, contributing to differing molecular stacking arrangements between the two structures. Thermal analysis, solvent-mediated polymorphic transformation, and theoretical calculations confirm a monotropic relationship between the two cocrystals.

Modeling Pseudo-Capacitance as Parallel Electrochemical Reactions

Pseudo-capacitors are attractive electrochemical energy storage devices for their superior rate performance over conventional batteries, and higher energy storage capacity over traditional capacitors. Despite the importance of these types of devices, their hybrid physics makes it difficult to simulate their performance; as such, a general and well-established physics-based mathematical model does not exist. Using MnO2 as a model pseudo-capacitive electrode, this work describes the electrochemical performance of the MnO2 electrode as two parallel redox reactions with independent exchange-current densities and thermodynamic relationships. One of the reactions mimics the fast time-constant of the near-surface reaction (typical in a pseudo-capacitor), while the second reaction has a larger time-constant, characteristic of insertion reactions. Both redox reactions could be parameterized through Butler-Volmer kinetics, and the time-constant of each reaction was controlled by its exchange current density, , and the sensitivity of the thermodynamic potential to the charge passed, . Because of this model’s simplicity and reliance on well-established mathematical descriptions of electrochemical kinetics and mass-transfer, it may have utility in modeling pseudo-capacitors in general, not just MnO2. In addition, the mathematical descriptions of the physics can be directly implemented with porous electrode theory, which is more amenable to mathematical device and component optimization.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by the LLNL-LDRD program under project 23-SI-002.

Effective estimation of entropy production with lacking data

Observing stochastic trajectories with rare transitions between states, practically undetectable on time scales accessible to experiments, makes it impossible to directly quantify the entropy production and thus infer whether and how far systems are from equilibrium. To solve this issue for Markovian jump dynamics, we show a lower bound that outperforms any other estimation of entropy production (including Bayesian approaches) in regimes lacking data due to the strong irreversibility of state transitions. Moreover, in the limit of complete irreversibility, our effective version of the thermodynamic uncertainty relation sets a lower bound to entropy production that depends only on nondissipative aspects of the dynamics. Such an approach is also valuable when dealing with jump dynamics with a deterministic limit, such as irreversible chemical reactions.