Traditional Thermodynamics Research Articles

Modeling phase or chemical reaction equilibrium with an equation of state, an unrealistic modeling

The traditional chemical thermodynamics considered the chemical potential then fugacity of a component in a single-phase, open system is just the one of the component in a co-existing phase of an equilibrium, multi-component, multi-phase system or in an equilibrium, chemical reaction system and the fugacity can be calculated with the equation of state of the single-phase, open system. Therefore, the most common method to model phase or chemical reaction equilibrium is with an equation of state. Obviously, modeling phase or chemical reaction equilibrium with an equation of state requires to the single-phase, open system is equivalent to the co-existing phase or the equilibrium, chemical reaction system. However, there are significant differences in the thermodynamics properties between the single-phase, open system and the co-existing phase or the equilibrium, chemical reaction system. Therefore, the chemical potential then fugacity of a component in the single-phase, open system is impossible the one of the component in the co-existing phase or in the equilibrium, chemical reaction system. That is, the calculated fugacity of a component in a single-phase, open system with the equation of state of the single-phase, open system is impossibly the fugacity of the component in a co-existing phase of an equilibrium, multi-component, multi-phase system or in an equilibrium, chemical reaction system. Therefore, it is unrealistic to model phase or chemical reaction equilibrium with an equation of state. For this, we establish the chemical potential differential formula of a component in a co-existing phase and in an equilibrium, chemical reaction system to calculate phase or chemical reaction equilibrium. The calculated values of solubility in molar concentration within the framework of the present theory equals exactly the measured values of solubility in molar concentration by the experiments.

Black holes thermodynamics with CFT re-scaling

In this paper, we study the thermodynamic behavior of charged AdS black holes in a conformal holographic extended thermodynamic. Our setup is constructed using a new dictionary that relates AdS black hole quantities to the corresponding dual conformal fields theory (CFT) one, with the conformal factor being treated as a variable thermodynamic. In this thermodynamic study, we investigate the critical phenomena of charged AdS black holes and their relationship to the central charge value, C. Additionally, we examine the phase transitions and black holes stability using the free energy and the heat capacity, respectively. Furthermore, by examining the chemical potential, we establish a criteria that differentiate between quantum and classical black hole’s behaviors. Our setup highlights one of the key findings, namely traditional black hole thermodynamics acts as a boundary between quantum and classical regimes.

Revisit nonequilibrium thermodynamics based on thermomass theory and its applications in nanosystems

Abstract The development of non-Fourier heat conduction models is encouraged by the invalidity of Fourier’s law to explain heat conduction in ultrafast or ultrasmall systems. The production of negative entropy will result from the combination of traditional nonequlibrium thermodynamics and non-Fourier heat conduction models. To resolve this paradox, extended irreversible thermodynamics (EIT) introduces a new state variable. However, real dynamics variables like force and momentum are still missing from nonequilibrium thermodynamics and EIT’s generalized force and generalized flux. Heat has both mass and energy, according to thermomass theory and Einstein’s mass-energy relation. The generalized heat conduction model containing non-Fourier effects was established by thermomass gas model. The thermomass theory reshapes the concept of the generalized force and flux, temperature, and entropy production in nonequilibrium thermodynamics and revisits the assumption for the linear regression of the fluctuations in Onsager reciprocal relation. The generalized heat conduction model based on thermomass theory has been used to study thermal conductivity, thermoelectric effect, and thermal rectification effect in nanosystems.

A Self-Charging Concentration Cell: Theory

Batteries are a key resource in the quest for sustainable energy. Here, the theoretical basis is presented for a new type of electrochemical concentration cell that might contribute to this enterprise. The cell, which has been successfully demonstrated in the laboratory, incorporates a chemically asymmetric membrane to drive anisotropic diffusion between two solution chambers; the resulting concentration difference powers the cell. In this study, the membrane’s operation is validated via three theoretical approaches: (i) traditional equilibrium thermodynamics; (ii) balancing drift and diffusion current densities; and (iii) the time-independent diffusion equation. The physical criteria for its operation are developed and its dimensionless variables identified. The cell’s maximum instantaneous power density might exceed 107 W/m3. Its self-charging capability should confer multiple advantages over traditional concentration cells (as well as over some voltaics), including improved thermodynamic efficiency, economy, and compactness. Commonalities with other electrochemical systems (e.g., liquid chromatography, metal corrosion, and solid state diodes) are discussed, and a physical instantiation of the cell is reviewed. Recent numerical simulations corroborate its essential processes.

Digital twin for zinc roaster furnace based on knowledge-guided variable-mass thermodynamics: Modeling and application

Roaster furnace is a large-scale equipment in zinc smelting process, which plays an significant role in safety production and enviromental protection. An accurate digital twin of roaster furnace can help to explore the influence of control parameters and serve as a test platform to verify the effectiveness of control strategies. However, the traditional thermodynamics cannot be used for dynamic modeling, and inability to measure key data greatly affects the accuracy of kinetic modeling. Therefore, this paper establishes a novel digital twin of zinc roaster furnace based on knowledge-guided variable-mass thermodynamics. First, based on the integration of mechanism analysis for mass balance and energy balance, a dynamic modeling method is proposed. Then, particle swarm optimization (PSO) algorithm is introduced to optimize the parameters of conversion rates guided by knowledge. Finally, by connecting the dynamic model with distributed control system (DCS) through OPC communication protocol, a digital twin of roaster furnace is constructed. Extensive experiments show that the simulation results of the digital twin roughly agree with the actual industrial data under steady and dynamic working conditions, and the application of the digital twin on the performance analysis of control parameters and testing of control strategies can provide guidance for the optimal control of roaster furnace.

Could Long-Term Stability Last Forever?

The subject of the present paper is to prove that the recently introduced conjecture of boundedness puts a ban over the view of stability as asymptotic property. This result comes in sharp contrast with the prescription of the traditional thermodynamics and statistical physics which consider the existence of equilibrium as asymptotic property of all systems. The difference commences from the use of infinitesimal calculus as the basic implement for modelling by the latter while the primary premise of the conjecture of boundedness is sustaining the energy/matter/information permanently bounded and finite. The latter property overrules the infinitesimal calculus as the major implement of modelling because, among all, it is proven that the traditional one suffers unsoluble difficulties.

Theoretical and experiments of mesoscopic statistical thermodynamics

Does thermodynamics still hold true for mecroscopic small systems with only limited degrees of freedom? Do concepts such as temperature, entropy, work done, heat transfer, isothermal processes, and the Carnot cycle remain valid? Does the thermodynamic theory for small systems need modifying or supplementing compared with traditional thermodynamics applicable to macroscopic systems? Taking a single-particle system for example, we investigate the applicability of thermodynamic concepts and laws in small systems. We have found that thermodynamic laws still hold true in small systems at an ensemble-averaged level. After considering the information erasure of the Maxwell's demon, the second law of thermodynamics is not violated. Additionally, 'small systems' bring some new features. Fluctuations in thermodynamic quantities become prominent. In any process far from equilibrium, the distribution functions of thermodynamic quantities satisfy certain rigorously established identities. These identities are known as fluctuation theorems. The second law of thermodynamics can be derived from them. Therefore, fluctuation theorems can be considered an upgradation to the second law of thermodynamics. They enable physicists to obtain equilibrium properties (e.g. free energy difference) by measuring physical quantities associated with non-equilibrium processes (e.g. work distributions). Furthermore, despite some distinct quantum features, the performance of quantum heat engine does not outperform that of classical heat engine. The introduction of motion equations into small system makes the relationship between thermodynamics and mechanics closer than before. Physicists can study energy dissipation in non-equilibrium process and optimize the power and efficiency of heat engine from the first principle. These findings enrich the content of thermodynamic theory and provide new ideas for establishing a general framework for non-equilibrium thermodynamics.

Atomistic characterization of the SiO2 high-density liquid/low-density liquid interface.

The equilibrium silica liquid-liquid interface between the high-density liquid (HDL) phase and the low-density liquid (LDL) phase is examined using molecular-dynamics simulation. The structure, thermodynamics, and dynamics within the interfacial region are characterized in detail and compared with previous studies on the liquid-liquid phase transition (LLPT) in bulk silica, as well as traditional crystal-melt interfaces. We find that the silica HDL-LDL interface exhibits a spatial fragile-to-strong transition across the interface. Calculations of dynamics properties reveal three types of dynamical heterogeneity hybridizing within the silica HDL-LDL interface. We also observe that as the interface is traversed from HDL to LDL, the Si/O coordination number ratio jumps to an unexpectedly large value, defining a thin region of the interface where HDL and LDL exhibit significant mixing. In addition, the LLPT phase coexistence is interpreted in the framework of the traditional thermodynamics of alloys and phase equilibria.

Nonequilibrium thermodynamics of electrochemical processes

<p indent="0mm">Electrochemical energy storage and conversion involve the transport and reaction of electrolytes in the porous electrodes and membranes. Understanding the microscopic and coupling mechanisms plays a crucial role in guiding the screening of electrolytes and electrode materials, as well as the design of the electrode-electrolyte interface. However, exploring the micro- or even nano-scale phenomena and the coupling effects of multi-physical fields through traditional electrochemical thermodynamics and kinetics theory and experimental techniques remains a challenge, which requires a novel modeling approach. In this review, based on non-equilibrium thermodynamics, a multi-physics-coupled modeling approach for electrochemical processes is proposed, and the feasibility and theoretical value of this approach are illustrated from three typical problems: mass transfer under electrical field, reaction and transport processes, and thermal effect.

Design and prediction method of dual working medium solar energy drying system

The design method of dual working medium solar energy drying system is proposed in this study. The operation control strategy of system is given. In order to obtain the drying chambers suitable air temperature controlling method and the expected operating environment of the system, the flat plate solar collector with dual-function hybrid dryer is regarded as a case. The influence of operation environment parameters on the performance of solar heating unit is analyzed by traditional thermodynamics, and five machine learning methods with python software are carried out to predict the thermal performance of solar heating unit. The effects of ambient temperature, solar radiation intensity and supply air flow of solar heating unit on the outlet air temperature and collecting efficiency are obtained. In addition, ambient relative humidity is found to be the most important effect factors for the outlet temperature of solar heating unit. Gradient Boosting Regression can be regarded as the best prediction performance with R2 of 0.98 and 0.94 on training data and testing data, respectively. This study also pointed out the direction for the application and development of the traditional thermodynamics and machine learning.

Thermodynamic carbon pump 2.0: Elucidating energy efficiency through the thermodynamic cycle

Excessive energy consumption has become a recurring obstacle for scaling up the development of CO2 capture. Thermodynamics can be applied to elucidate this issue through an in-depth analysis of the energy conversion mechanism. A better understanding of energy efficiency can be attained through a developed description of the thermodynamic carbon pump (TCP), which is presented as an updated version of the carbon pump reported in our previous study. Extending the scope of traditional thermodynamics also enables a novel application scenario of the thermodynamic cycle into specific industrial technologies. The TCP cycle is developed inspired by the development of the heat pump cycle, to evaluate the performance of the actual CO2 capture technology. As the coefficient of performance for CO2 capture (COPCO2) is defined, the upper bound of energy conversion efficiency in the specific technology can be illustrated. The ideal TCP cycle is depicted in the μ-n diagram first, which is extended into temperature-dependent three-dimensional (3D) coordinates. Considering the process of temperature swing adsorption (TSA) for CO2 capture as a case study, COPCO2 in the actual TSA cycle is obtained in the range of 1.81–2.21, which is half of that in the ideal cycle. Consequently, the normalized performance evaluation of the actual technology can be obtained.

Aero Engine Gas-Path Fault Diagnose Based on Multimodal Deep Neural Networks

Aeroengine, served by gas turbine, is a highly sophisticated system. It is a hard task to analyze the location and cause of gas-path faults by computational-fluid-dynamics software or thermodynamic functions. Thus, artificial intelligence technologies rather than traditional thermodynamics methods are widely used to tackle this problem. Among them, methods based on neural networks, such as CNN and BPNN, cannot only obtain high classification accuracy but also favorably adapt to aeroengine data of various specifications. CNN has superior ability to extract and learn the attributes hiding in properties, whereas BPNN can keep eyesight on fitting the real distribution of original sample data. Inspired by them, this paper proposes a multimodal method that integrates the classification ability of these two excellent models, so that complementary information can be identified to improve the accuracy of diagnosis results. Experiments on several UCR time series datasets and aeroengine fault datasets show that the proposed model has more promising and robust performance compared to the typical and the state-of-the-art methods.

Structural phase transition of the ion crystals embedded in an optical lattice

The structural phase transition (SPT) occurring in trapped-ion systems is a typical many-body physics, and the SPT induced by the thermal effect represents a special thermodynamic phenomenon between traditional thermodynamics and quantum thermodynamics. We explore this thermal-effect-induced SPT by embedding trapped $^{40}\mathrm{Ca}^{+}$ ion crystals in an optical lattice, in which the ion crystals are confined by a surface-electrode trap and laser-cooled down to a temperature of several millikelvins. The considered thermal effect, leading to a temperature variation of tens of microkelvins in the SPT, comes completely from the optical lattice, which is independent of the laser irradiation regarding cooling of the ion crystals. In comparison with previous work [J. Li et al., Phys. Rev. A 99, 063402 (2019)], the present investigation helps to further clarify the effect of thermal fluctuation and further explore the positive role of the fluctuation in thermodynamics at the atomic level, even for potentially practical applications.

Thermodynamics in Ecology-An Introductory Review.

How to predict the evolution of ecosystems is one of the numerous questions asked of ecologists by managers and politicians. To answer this we will need to give a scientific definition to concepts like sustainability, integrity, resilience and ecosystem health. This is not an easy task, as modern ecosystem theory exemplifies. Ecosystems show a high degree of complexity, based upon a high number of compartments, interactions and regulations. The last two decades have offered proposals for interpretation of ecosystems within a framework of thermodynamics. The entrance point of such an understanding of ecosystems was delivered more than 50 years ago through Schrödinger’s and Prigogine’s interpretations of living systems as “negentropy feeders” and “dissipative structures”, respectively. Combining these views from the far from equilibrium thermodynamics to traditional classical thermodynamics, and ecology is obviously not going to happen without problems. There seems little reason to doubt that far from equilibrium systems, such as organisms or ecosystems, also have to obey fundamental physical principles such as mass conservation, first and second law of thermodynamics. Both have been applied in ecology since the 1950s and lately the concepts of exergy and entropy have been introduced. Exergy has recently been proposed, from several directions, as a useful indicator of the state, structure and function of the ecosystem. The proposals take two main directions, one concerned with the exergy stored in the ecosystem, the other with the exergy degraded and entropy formation. The implementation of exergy in ecology has often been explained as a translation of the Darwinian principle of “survival of the fittest” into thermodynamics. The fittest ecosystem, being the one able to use and store fluxes of energy and materials in the most efficient manner. The major problem in the transfer to ecology is that thermodynamic properties can only be calculated and not measured. Most of the supportive evidence comes from aquatic ecosystems. Results show that natural and culturally induced changes in the ecosystems, are accompanied by a variations in exergy. In brief, ecological succession is followed by an increase of exergy. This paper aims to describe the state-of-the-art in implementation of thermodynamics into ecology. This includes a brief outline of the history and the derivation of the thermodynamic functions used today. Examples of applications and results achieved up to now are given, and the importance to management laid out. Some suggestions for essential future research agendas of issues that needs resolution are given.

Dynamics of the Berezinskii–Kosterlitz–Thouless transition in a photon fluid

In addition to enhancing confinement, restricting optical systems to two dimensions gives rise to new photonic states, modified transport and distinct nonlinear effects. Here we explore these properties in combination and experimentally demonstrate a Berezinskii–Kosterlitz–Thouless phase transition in a nonlinear photonic lattice. In this topological transition, vortices are created in pairs and then unbind, changing the dynamics from that of a photonic fluid to that of a plasma-like gas of free (topological) charges. We explicitly measure the number and correlation properties of free vortices, for both repulsive and attractive interactions (the photonic equivalent of ferromagnetic and antiferromagnetic conditions), and confirm the traditional thermodynamics of the Berezinskii–Kosterlitz–Thouless transition. We also suggest a purely fluid interpretation, in which vortices are nucleated by inhomogeneous flow and driven by seeded instability. The results are fundamental to optical hydrodynamics and can impact two-dimensional photonic devices if temperature and interactions are not controlled properly. A topological transition in a nonlinear photonic lattice results in new vortex dynamics and a change from photonic fluid behaviour to that of a plasma-like gas.

Thermotropic Two-Zone Model of Fuel Combustion in an Internal Combustion Engine

A thermotropic two-band model is proposed for the fuel combustion in an internal combustion engine. In the model, the nonequilibrium combustion process is represented by three interrelated equilibrium processes within a complex thermodynamic system. This provides a better approximation of the mean values and local values of the gas than in traditional thermodynamic approaches. Since this method is consistent with traditional thermodynamics and mathematically simple, it may be used for teaching purposes at universities.

Nonequilibrium phase transitions and pattern formation as consequences of second-order thermodynamic induction.

Development of thermodynamic induction up to second order gives a dynamical bifurcation for thermodynamic variables and allows for the prediction and detailed explanation of nonequilibrium phase transitions with associated spontaneous symmetry breaking. By taking into account nonequilibrium fluctuations, long-range order is analyzed for possible pattern formation. Consolidation of results up to second order produces thermodynamic potentials that are maximized by stationary states of the system of interest. These potentials differ from the traditional thermodynamic potentials. In particular a generalized entropy is formulated for the system of interest which becomes the traditional entropy when thermodynamic equilibrium is restored. This generalized entropy is maximized by stationary states under nonequilibrium conditions where the standard entropy for the system of interest is not maximized. These nonequilibrium concepts are incorporated into traditional thermodynamics, such as a revised thermodynamic identity and a revised canonical distribution. Detailed analysis shows that the second law of thermodynamics is never violated even during any pattern formation, thus solving the entropic-coupling problem. Examples discussed include pattern formation during phase front propagation under nonequilibrium conditions and the formation of Turing patterns. The predictions of second-order thermodynamic induction are consistent with both observational data in the literature as well as the modeling of this data.

A PC-SAFT model for hydrocarbons I: Mapping aromatic π-π interactions onto a dipolar free energy

Aromaticity is an important property of many petroleum derived streams. Traditional thermodynamics tools (e.g., cubic equations of state) do not provide any special treatment to these aromatic hydrocarbons. A feature which discriminates aromatics from paraffins is that aromatic rings exhibit anisotropic π-π interactions. Accounting for this key difference between aromatic and non-aromatic hydrocarbons in an equation of state will allow for a level of predictability which is not possible with our current tools. By mapping the anisotropy of π-π attractions onto a dipolar free energy, we develop a simple and powerful treatment of aromatic hydrocarbons within the PC-SAFT equation state. We demonstrate that this approach provides a substantial increase in performance over the standard non-polar treatment of aromatic molecules. The methodology developed is used to develop a generalized hydrocarbon model in instalment II of this series.

A hybrid multicomponent model for the vaporisation simulation of gasoline drop

A Hybrid multicomponent drop vaporisation model inspired by both the continuous thermodynamics and discrete component approaches is developed to improve the simulation of drop vaporisation process of petroleum fuels. Using the hybrid model, the petroleum fuel is assumed to be the mixture of several hydrocarbon species groups, and the composition of each group is described by an individual gamma distribution about the molecular weight. Compared to a traditional continuous thermodynamics model based on a single gamma distribution, the hybrid model is first proved to be more adequate in the description of petroleum fuel composition. For each hydrocarbon species group, the normal boiling point is assumed to be linearly correlated with the molecular weight, and improved prediction of normal boiling point is obtained compared to a traditional model. On this basis, improved prediction of gasoline distillation curve is also achieved. The hybrid model is finally used to simulate the vaporisation of a single gasoline drop, and a more complex variation of liquid-phase composition is observed during the vaporisation process. The distribution of species composition in each group moves in the direction of increasing molecular weight, and a significant change in the overall molar proportion of the species groups in the liquid drop is also observed during the vaporisation.

Quantum Thermodynamics at Strong Coupling: Operator Thermodynamic Functions and Relations.

Identifying or constructing a fine-grained microscopic theory that will emerge under specific conditions to a known macroscopic theory is always a formidable challenge. Thermodynamics is perhaps one of the most powerful theories and best understood examples of emergence in physical sciences, which can be used for understanding the characteristics and mechanisms of emergent processes, both in terms of emergent structures and the emergent laws governing the effective or collective variables. Viewing quantum mechanics as an emergent theory requires a better understanding of all this. In this work we aim at a very modest goal, not quantum mechanics as thermodynamics, not yet, but the thermodynamics of quantum systems, or quantum thermodynamics. We will show why even with this minimal demand, there are many new issues which need be addressed and new rules formulated. The thermodynamics of small quantum many-body systems strongly coupled to a heat bath at low temperatures with non-Markovian behavior contains elements, such as quantum coherence, correlations, entanglement and fluctuations, that are not well recognized in traditional thermodynamics, built on large systems vanishingly weakly coupled to a non-dynamical reservoir. For quantum thermodynamics at strong coupling, one needs to reexamine the meaning of the thermodynamic functions, the viability of the thermodynamic relations and the validity of the thermodynamic laws anew. After a brief motivation, this paper starts with a short overview of the quantum formulation based on Gelin & Thoss and Seifert. We then provide a quantum formulation of Jarzynski’s two representations. We show how to construct the operator thermodynamic potentials, the expectation values of which provide the familiar thermodynamic variables. Constructing the operator thermodynamic functions and verifying or modifying their relations is a necessary first step in the establishment of a viable thermodynamics theory for quantum systems. We mention noteworthy subtleties for quantum thermodynamics at strong coupling, such as in issues related to energy and entropy, and possible ambiguities of their operator forms. We end by indicating some fruitful pathways for further developments.