Thermodynamic Entropy Research Articles

Entropy Generation-Based Analysis of Laminar Magneto-Convection in Different Cross-Section Channel Filled with Ferrofluid and Subjected to Partial and Full Magnetic Fields

Heat transfer and entropy generation of laminar flow of a ferrofluid in different cross-section channel subjected to partial and full magnetic field are investigated in this study. A constant heat flux condition was applied on the external surface. The conservation equations (mass, momentum, and energy) are solved numerically via the finite volume method with a second-order precision. The effects of fully or partially applying a magnetic field with different directions and intensities on thermodynamic features, heat transfer, and entropy generation have been investigated. Analyses were carried out in four different cross-section channels, namely triangular, rectangular, circular, and elliptical. Results indicate that the circular cross-section channel provides higher heat transfer rates and lower entropy generation than non-circular cross-section channels.

A Perspective on Lindblad’s Non-Equilibrium Entropy

In 1983 Göran Lindblad published a monograph on nonequilibrium thermodynamics. We here summarize the contents of this book, and provide a perspective on its relation to later developments in statistical physics and quantum physics. We high-light two aspects. The first is the idea that while all unitaries can be allowed in principle, different theories result from limiting which unitary evolutions are realized in the real world. The second is that Lindblad’s proposal for thermodynamic entropy (as opposed to information-theoretic entropy) foreshadows much more recent investigations into optimal quantum transport which is a current research focus in several fields.

Unitary paradox of cosmological perturbations

If we interpret the Bekenstein–Hawking entropy of the Hubble horizon as thermodynamic entropy, then the entanglement entropy of the superhorizon modes of curvature perturbation entangled with the subhorizon modes will exceed the Bekenstein–Hawking bound at some point; we call this the unitary paradox of cosmological perturbations by analogy with black hole. In order to avoid a fine-tuned problem, the paradox must occur during the inflationary era at the critical time [Formula: see text] (in Planck units), where [Formula: see text] is the first Hubble slow-roll parameter and [Formula: see text] is the Hubble rate during inflation. If we instead accept the fine-tuned problem, then the paradox will occur during the dark energy era at the critical time [Formula: see text], where [Formula: see text] is the Hubble rate dominated by dark energy, [Formula: see text] is the total number of e-folds of inflation and [Formula: see text] is a purification factor that takes the range [Formula: see text].

Permutation entropy of indexed ensembles: quantifying thermalization dynamics

We introduce ‘PI-Entropy’ (the Permutation entropy of an Indexed ensemble) to quantify mixing due to complex dynamics for an ensemble ρ of different initial states evolving under identical dynamics. We find that acts as an excellent proxy for the thermodynamic entropy but is much more computationally efficient. We study 1-D and 2D iterative maps and find that dynamics distinguish a variety of system time scales and track global loss of information as the ensemble relaxes to equilibrium. There is a universal S-shaped relaxation to equilibrium for generally chaotic systems, and this relaxation is characterized by a shuffling timescale that correlates with the system’s Lyapunov exponent. For the Chirikov Standard Map, a system with a mixed phase space where the chaos grows with nonlinear kick strength K, we find that for high K, behaves like the uniformly hyperbolic 2D Cat Map. For low K we see periodic behavior with a relaxation envelope resembling those of the chaotic regime, but with frequencies that depend on the size and location of the initial ensemble in the mixed phase space as well as K. We discuss how adapts to experimental work and its general utility in quantifying how complex systems change from a low entropy to a high entropy state.

Properties of Spherically Symmetric Black Holes in the Generalized Brans-Dicke Modified Gravitational Theory.

The many problems faced by the theory of general relativity (GR) have always motivated us to explore the modified theory of GR. Considering the importance of studying the black hole (BH) entropy and its correction in gravity physics, we study the correction of thermodynamic entropy for a kind of spherically symmetric black hole under the generalized Brans-Dicke (GBD) theory of modified gravity. We derive and calculate the entropy and heat capacity. It is found that when the value of event horizon radius r+ is small, the effect of the entropy-correction term on the entropy is very obvious, while for larger values r+, the contribution of the correction term on entropy can be almost ignored. In addition, we can observe that as the radius of the event horizon increases, the heat capacity of BH in GBD theory will change from a negative value to a positive value, indicating that there is a phase transition in black holes. Given that studying the structure of geodesic lines is important for exploring the physical characteristics of a strong gravitational field, we also investigate the stability of particles' circular orbits in static spherically symmetric BHs within the framework of GBD theory. Concretely, we analyze the dependence of the innermost stable circular orbit on model parameters. In addition, the geodesic deviation equation is also applied to investigate the stable circular orbit of particles in GBD theory. The conditions for the stability of the BH solution and the limited range of radial coordinates required to achieve stable circular orbit motion are given. Finally, we show the locations of stable circular orbits, and obtain the angular velocity, specific energy, and angular momentum of the particles which move in circular orbits.

Exploring the shear viscosity in four-dimensional planar black holes beyond general relativity

The well known shear viscosity to entropy density ratio ($\eta /s$) cannot be computed when the black hole space-time has zero thermodynamic entropy. This is the case, for example, when General Relativity in four dimensions is complemented with Critical Gravity, or in particular scenarios within the Four-dimensional-scalar-Gauss-Bonnet theories. Recently, it has been shown that the zero entropy situation can be overcome in these examples by introducing suitable matter fields. With this at hand, in this paper we analyze each case and the impact of these extra sources in the ratio, in terms of their new parameters. We find that, while the $\eta /s$ ratio remains constant and insensitive in the former, this is not the case for the latter. To perform the calculations, we construct a Noether charge using a space-like Killing vector. The accuracy of the aforementioned findings is supported by the Kubo formalism.

A comparative study of experimental and advanced modelling analysis for adsorption of Cd (II) from aqueous solution by Melia azedarach L. charcoal powder

The present study deals with the preparation and characterization of Melia azedarach L. twigs charcoal powder (MAT-CP) followed by batch and column adsorption experiments to appraise its Cd(II) removal efficiency from aqueous solution. The characterization of charcoal was done using XRD, FTIR, FESEM, EDX and BET analysis. Batch adsorption study was conducted with varied variables including adsorbent dose, contact time, temperature, pH and agitation speed. Resultant data was suitably fitted in Langmuir isotherm model exhibiting a maximum 196.078 mg/g adsorption capacity. Kinetic studies revealed that the adsorption followed Pseudo-second order kinetic while thermodynamic analysis (enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°)) revealed the interaction to be thermodynamically favorable and endothermic. Regeneration of adsorbent was also done and the reactivated MAT-CP was repeatedly used as adsorbent. In fixed-bed column investigation, variables such as flow rate, initial metal concentration and column bed height were varied to obtain breakthrough curves (BTCs). The column adsorption was optimally obtained at 2.5 mL/min flow rate, 25 mg/L of Cd(II) concentration and 5 cm bed height. Column adsorption modeling reflected higher R2 and adsorption capacity using Thomas and Nelson-Yoon models. The present study advocates the MAT-CP as an efficient adsorbent for Cd(II) removal from aqueous solution.

Thermal geometries and the Joule–Thomson expansion of modified charged and slowly rotating black holes

Thermodynamics of charged and slowly rotating black holes in 4D Gauss–Bonnet gravity has attracted a great deal of attention due to its intrinsic complications and rich phase structures. In this paper, we revisit the thermodynamics of charged and slowly rotating black holes and provide the correct thermodynamic volume and entropy. Thermodynamic geometries are a powerful tool to study the microstructure of black holes. Based on the Hessian matrix of the black hole mass, we introduce thermodynamic geometric methods and give its scalar curvature (Ruppeiner and Weinhold). Furthermore, we investigate the Joule–Thomson expansion of slowly rotating black hole in 4D Gauss–Bonnet gravity in this research study. Interestingly, we explicitly state that the expression of the Joule–Thomson coefficient is obtained from the basic formulas of enthalpy and temperature. Then, we obtain the isenthalpic curve in the T − P graph and demonstrate the cooling–heating region by the inversion curve. The inversion temperature and inversion curves are obtained, and we investigate the similarities and differences between van der Waals fluids and charged fluids.

Observational entropy, coarse-grained states, and the Petz recovery map: information-theoretic properties and bounds

Observational entropy provides a general notion of quantum entropy that appropriately interpolates between Boltzmann’s and Gibbs’ entropies, and has recently been argued to provide a useful measure of out-of-equilibrium thermodynamic entropy. Here we study the mathematical properties of observational entropy from an information-theoretic viewpoint, making use of recently strengthened forms of the monotonicity property of quantum relative entropy. We present new bounds on observational entropy applying in general, as well as bounds and identities related to sequential and post-processed measurements. A central role in this work is played by what we call the ‘coarse-grained’ state, which emerges from the measurement’s statistics by Bayesian retrodiction, without presuming any knowledge about the ‘true’ underlying state being measured. The degree of distinguishability between such a coarse-grained state and the true (but generally unobservable) one is shown to provide upper and lower bounds on the difference between observational and von Neumann entropies.

Rhizosphere engineering for sustainable crop production: entropy-based insights.

There is a growing interest in exploring interactions at root-soil interface in natural and agricultural ecosystems, but an entropy-based understanding of these dynamic rhizosphere processes is lacking. We have developed a new conceptual model of rhizosphere regulation by localized nutrient supply using thermodynamic entropy. Increased nutrient-use efficiency is achieved by rhizosphere management based on self-organization and minimized entropy via equilibrium attractors comprising (i) optimized root strategies for nutrient acquisition and (ii) improved information exchange related to root-soil-microbe interactions. The cascading effects through different hierarchical levels amplify the underlying processes in plant-soil system. We propose a strategy for manipulating rhizosphere dynamics and improving nutrient-use efficiency by localized nutrient supply with minimization of entropy to underpin sustainable food/feed/fiber production.

Lindbladian route towards thermalization of a Luttinger liquid

We study the nonequilibrium dynamics of a Luttinger liquid after a simultaneous quantum quench of the interaction and dissipative quench to the environment within the realm of the Lindblad equation. When the couplings to the environment satisfy detailed balance, the system is destined to thermalize, which we follow using bosonization. The thermodynamic entropy of the system, which also encodes information about the entanglement with the environment, either exhibits a maximum and minimum or grows monotonically before reaching its thermal value in a universal fashion. The single-particle density matrix reveals interesting features in the spatiotemporal ``phase diagram,'' including thermal, prethermal, and dissipation enhanced sudden quench Luttinger liquid behavior, as well as dissipation, enhanced Fermi liquid response.

Modeling fatigue life and hydrogen embrittlement of bcc steel with unified mechanics theory

The fatigue life estimation of metals operating in hydrogen-rich environments such as hydrogen pipelines, hydrogen-burning internal combustion engines, etc. is important. Studies in the past 40 years have shown that the diffusion of hydrogen into steel and other metals causes various chemical reactions, hydrogen-material interactions, and microstructural changes. That leads to hydrogen embrittlement (HE) and other types of hydrogen damage mechanisms including hydrogen environmentally assisted cracking (HEAC). Hydrogen embrittlement mechanisms, such as hydrogen-enhanced localized plasticity (HELP) and hydrogen-enhanced decohesion (HEDE) can have synergetic effects in steel depending on the hydrogen concentration level. At concentrations above and below the critical hydrogen concentration, HEDE and HELP dominate the embrittlement process, respectively. Different HE mechanisms result in distinctly different fracture modes, both ductile and fully brittle. The ultrasonic vibration fatigue life of bcc steel with a ferrite-pearlite microstructure pre-charged with hydrogen at different concentrations is studied. Modeling is based on the unified mechanics theory (UMT), which does not need any empirical dissipation/degradation potential function or an empirical void evolution function. However, the UMT does require analytical derivation of the thermodynamic fundamental equation of the material, which is used to calculate the thermodynamic state index (TSI) of the material. The UMT is ab-initio unification of the second law of thermodynamics and the universal laws of motion of Newton [1]. Dissipation/degradation evolution is governed by Boltzmann's second law of thermodynamics entropy formulation. The original contribution of this paper is the derivation of the thermodynamic fundamental equation of pre-hydrogen embrittled bcc steel subjected to ultrasonic very high cycle fatigue and the numerical simulations of fatigue life estimation using the proposed novel model. The synergetic interaction of hydrogen embrittlement mechanisms in steel and other metallic materials, i.e., HELP and HEDE at different hydrogen concentrations (HELP + HEDE model) is also studied, reviewed, and applied. The synergetic effects between ultrasonic vibration fatigue life and synergistically active hydrogen embrittlement mechanisms in low carbon bcc steel (S355J2+N, equivalent to ASTM A656), according to the HELP + HEDE model for HE, is modeled for the first time using UMT and also thoroughly discussed.

Quantum entanglement and the thermal hadron

This paper tests how effectively the bound states of strongly-interacting gauge theories are amenable to an emergent description as a thermal ensemble. This description can be derived from a conjectured minimum free-energy principle, with the entanglement entropy of two-parton subsystems playing the role of thermodynamic entropy. This allows us to calculate the ground-state hadron spectrum and wave function over a wide range of parton masses without solving the Schr\"odinger equation. We carry out this analysis for certain illustrative models in ($1+1$) dimensions and discuss prospects for higher dimensions.

Optimization of the performance of M-Cycle indirect evaporative cooling via thermodynamic approach

ABSTRACT For the further energy conservation, the study on the optimizing the M-Cycle indirect evaporative cooling (MIEC) performance is meaningful. With the aim of the optimization, a model of a general MIEC system was established, the thermodynamic entropy production optimization method was used to fully reflect the energy quality and irreversibility. The inlet parameters, supply air ratio, dew point temperature efficiency, unit-cooling capacity and Entropy Production Number were used to analyze and improve the cooling and thermodynamic performance of the general MIEC. A total of 6750 air treatment processes have been studied with the self-programmed FORTRA. It is concluded that when the inlet temperature is high, with the increase in inlet relative humidity, the unit-cooling capacity of the system greatly improves while the Entropy Production Number increases relatively small. When the ambient humidity variation range is large, the irreversible loss of the system can be reduced by coordinating the supply air ratio and dew point temperature efficiency of the MIEC system. Ultimately, the results of this study will provide theoretical reference for the design and operation of the practical engineering of the MIEC.

Living Plants Ecosystem Sensing: A Quantum Bridge between Thermodynamics and Bioelectricity.

The in situ measurement of the bioelectric potential in xilematic and floematic superior plants reveals valuable insights into the biological activity of these organisms, including their responses to lunar and solar cycles and collective behaviour. This paper reports on the "Cyberforest Experiment" conducted in the open-air Paneveggio forest in Valle di Fiemme, Trento, Italy, where spruce (i.e., Picea abies) is cultivated. Our analysis of the bioelectric potentials reveals a strong correlation between higher-order complexity measurements and thermodynamic entropy and suggests that bioelectrical signals can reflect the metabolic activity of plants. Additionally, temporal correlations of bioelectric signals from different trees may be precisely synchronized or may lag behind. These correlations are further explored through the lens of quantum field theory, suggesting that the forest can be viewed as a collective array of in-phase elements whose correlation is naturally tuned depending on the environmental conditions. These results provide compelling evidence for the potential of living plant ecosystems as environmental sensors.

(Invited) Golden jubilee of solitons in optical fibers: For young scientists who love creative works

A memoir related to the discovery of optical soliton is presented with an intention of stimulating motivation of young scientists for creative works. Soliton is clearly a more desirable pulse for stable transmission of information in optical fiber medium. However, I would like to emphasize additional capability of a soliton pulse as information carrier without increasing thermodynamical entropy and invite the reader’s attention to possible relation to information processing in biological systems.

Thermodynamic Entropy Balances in Perfect Mixing Apparatuses

Thermodynamic Entropy Balances in Perfect Mixing Apparatuses

러시아어 물리적 행위 동사 그룹의 의미적 교차성

In the study of the thematic verb groups, in particular, the study of the physical action verb has a extremely important meaning. This verb represents a semantic group that essentially conveys the meaning of the verb for action, i.e. aggressive action. By analyzing the semantic structure of physical action verbs, we find meaningful intersections between the verb subgroups, the creative verb group and the destructive verb group. The semantic intersection of creation verbs and destruction verbs can be easily explained from a linguistic point of view. The action designated by the physical action verb involves a change of object. The creation verb and destruction verb have the same semantic structure, but only differ in the interest of the speaker. In creative verbs, the object of the action(=Result) appears to have a higher communicative rank than the material(=Patient). On the other hand, Patient, the object of the physical action in the destructive verb, would rank lower in communication than Result. The semantic correlation between creation and destruction is naturally explained through the entropy of thermodynamics. In a world where energy is constant, an equilibrium is maintained among the three energies of the original object, the physical action, and the object that changes due to the action. Also, just as the meaning of creation and destruction is distinguished according to the speaker's intention and purpose, in thermodynamics, the act of creation and destruction is distinguished according to the direction toward maximum entropy: Is the entropy of the changed object the result of adding negative entropy to the energy of the original object? Or is it the result of applying negative entropy to the world surrounding the object? In addition, the fact that entropy performs a natural function of bringing the universe into a state of dynamic equilibrium suggests that it is the verb of destruction what takes the lead intersecting the meanings of creation and destruction.

Electrospun NiPd Nanoparticles Supported on Polymer Membrane Nanofibers as an Efficient Catalyst for NaBH4 Dehydrogenation.

Sodium borohydride (SBH) hydrolysis in the presence of cheap and efficient catalysts has been proposed as a safe and efficient method for generating clean hydrogen energy for use in portable applications. In this work, we synthesized bimetallic NiPd nanoparticles (NPs) supported on poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers (PVDF-HFP NFs) via the electrospinning approach and reported an in-situ reduction procedure of the NPs being prepared by alloying Ni and Pd with varying Pd percentages. The physicochemical characterization provided evidence for the development of a NiPd@PVDF-HFP NFs membrane. The bimetallic hybrid NF membranes exhibited higher H2 production as compared to Ni@PVDF-HFP and Pd@PVDF-HFP counterparts. This may be due to the synergistic effect of binary components. The bimetallic Ni1-xPdx(x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3)@PVDF-HFP nanofiber membranes exhibit composition-dependent catalysis, in which Ni75Pd25@PVDF-HFP NF membranes demonstrate the best catalytic activity. The full H2 generation volumes (118 mL) were obtained at a temperature of 298 K and times 16, 22, 34 and 42 min for 250, 200, 150, and 100 mg dosages of Ni75Pd25@PVDF-HFP, respectively, in the presence of 1 mmol SBH. Hydrolysis utilizing Ni75Pd25@PVDF-HFP was shown to be first order with respect to Ni75Pd25@PVDF-HFP amount and zero order with respect to the [NaBH4] in a kinetics study. The reaction time of H2 production was reduced as the reaction temperature increased, with 118 mL of H2 being produced in 14, 20, 32 and 42 min at 328, 318, 308 and 298 K, respectively. The values of the three thermodynamic parameters, activation energy, enthalpy, and entropy, were determined toward being 31.43 kJ mol-1, 28.82 kJ mol-1, and 0.057 kJ mol-1 K-1, respectively. It is simple to separate and reuse the synthesized membrane, which facilitates their implementation in H2 energy systems.

An improved method for fatigue life prediction of metal materials based on thermodynamic entropy

To determine the relationship between thermodynamic entropy generation rate and cumulative entropy and fatigue performance of metal components during fatigue. The surface temperatures of the specimens under different loading amplitudes and frequencies were recorded by infrared thermography. The effect of internal friction is not considered. Then the entropy generation rate and cumulative entropy are calculated, and the relationship between fatigue life and entropy is constructed. The calculation results show that under the same loading frequency, the entropy generation rate is proportional to the loading amplitude, the fatigue cycle is relatively low, and the cumulative entropy is inversely proportional to the loading amplitude. The cumulative entropy is only related to the loading amplitude, but not the loading frequency. A fatigue life prediction model based on the thermodynamic entropy of metals is established, which can be used for the real-time assessment of fatigue damage of metal components.