Thermodynamic Properties Research Articles

Effects of global monopole on thermodynamic properties and Shannon entropy under a Mie-type potential

Effects of global monopole on thermodynamic properties and Shannon entropy under a Mie-type potential

Key phase diagram experiments and thermodynamic modeling of the ZnO‒B2O3, ZnO‒SiO2, and ZnO‒B2O3‒SiO2 systems

AbstractThermodynamic modeling of binary ZnO‒B2O3 and ZnO‒SiO2 systems and ternary ZnO‒B2O3‒SiO2 system were carried out based on the critical evaluation and optimization of all available phase diagram and thermodynamic property data using the CALculation of PHAse Diagram (CALPHAD) method. To resolve the inconsistency among the available phase diagram data in ternary ZnO‒B2O3‒SiO2 system, key phase diagram experiment was carried out using classical quenching method followed by electron probe micro‐analysis and X‐ray diffraction phase determination. The liquid oxide solution was described using the modified quasichemical model accounting for a short‐range ordering behavior in molten oxide solution. Thermodynamic models with optimized model parameters were used to predict the phase diagram and thermodynamic properties of the ternary systems.

Theoretical Study of Position-Dependent Mass Particle in Cosmic String Space-Time and External Magnetic Field

In this work, we discuss the case of a non-relativistic quantum particle in the cosmic string space-time under the influence of the presence of external magnetic and exponential potential. It’s shown with the help of the Laplace transform method the second-order differential equation of the Schrodinger equation is solvable where it is reduced to a first-order differential equation. We obtain the eigenfunction and the non-relativistic energy spectrum. In addition, these results may be useful in the future study of thermodynamic, optic, and magnetic properties of the atomic interaction of a system particle. Keywords: Schrodinger equation; Laplace transform method; Position dependent mass; External magnetic field; Cosmic string

Drastic enhancement of electronic correlations induced by hydrogen insertion in the cerium intermetallic compound CeFeSi.

We report a comparative study of two cerium-based intermetallic compounds: CeFeSi with an anti-PbFCl type structure, and CeFeSiH with a ZrCuSiAs type structure. The latter is obtained from CeFeSi through hydrogen insertion. Our results are based on X-rays, transport, thermodynamic and magnetic measurements. While the tetragonal structure with P4/nmm symmetry remains unchanged after hydrogen insertion, the thermodynamic, magnetic, and transport properties change drastically. On the one hand, CeFeSi behaves as a Pauli paramagnet with a small Sommerfeld coefficient, indicating the absence of 4f electron physics. On the other hand, our study shows that CeFeSiH exhibits strong magnetic fluctuations with a magnetic transition at 3.5 K, and coherent Kondo-lattice heavy-fermion features.

Thermodynamic properties of non-azeotropic refrigerant heat pumps under full operating conditions with non-phase-change heat sinks and heat soucres

ABSTRACT When using pure refrigerants in heat pump, a significant temperature mismatch arises between hot and cold fluids within the evaporator and condenser, adversely impacting the thermal efficiency of system. To mitigate this issue, we incorporated non-azeotropic refrigerant blends such as R1233zd(e)/R152a, 1224 yd(z)/R152a and 1234ze(z)/R152a into heat pumps devoid of phase-change heat sinks and sources. Through rigorous examination of the temperature glide characteristics of these refrigerants, we determined an optimal R152a composition of 0.3, resulting in COPs of 3.326, 3.36, and 3.605 for the respective heat pumps. Our analysis further delved into heat pump configurations, revealing that the COP of the regenerative configuration could be substantially elevated from 3.36 (in the simple configuration) to 3.79. Additionally, the maximum temperature observed in the two-stage compression configuration was significantly lower compared to the regenerative setup. A comprehensive thermodynamic assessment = across all operating conditions indicated that COP of all configurations decreases markedly as heat production diminishes below 50% of full load. Conversely, when heat production exceeds 50% of full load, the COP remains relatively stable across different heat production levels. Notably, the COP of the regenerative configuration closely approximates that of the two-stage configuration. Considering factors such as investment cost, system complexity and operational efficiency, the regenerative configuration stands out as the optimal choice across all operating conditions.

Prediction of Molar Entropy of Gaseous Molecules for a New Pὃschl‐Teller Potential Model

ABSTRACTThe Pὃschl–Teller potential is a molecular potential energy function that has only been reported for bound state. This Pὃschl–Teller potential is a good representation of many molecules and has not been examined for any thermodynamic property irrespective of its fitness for molecular study. In this study, the molar entropy of four molecules (Pbr, BBr, CsCl, and CsO molecules) is calculated via the molar partition function. The predicted results are compared with the experimental data recorded in the National Institute of Standards and Technology (NIST) database. It is noted that the predicted values for the studied molecules perfectly agree with the experimental results with the following average absolute percentage deviation, PBr is 0.0158%, BBr is 0.0053%, CsCl is 0.0020%, and CsO is 0.0052%. The present model reproduces better results for CsCl and CsO molecules compared to the shifted Tietz–Wei potential and improved Tietz‐oscillator previously reported whose average absolute percentage deviation are 0.361% and 0.284% for CsCl and 0.272% and 0.228% for CsO, respectively.

Effects of conical singularity and Wu-Yang magnetic monopole on thermodynamic properties of harmonic oscillator interacting with potential

Abstract This paper investigates the thermodynamic properties of the harmonic oscillator system in a conical singularities background. Moreover, we incorporate a Wu-Yang magnetic monopole (WYMM) and inverse square potential into the quantum system and analyze the resulting effects. Using analytical methods, we derive the energy eigenvalues and study the thermodynamic properties, such as the partition function, Helmholtz free energy, Gibbs's free energy and specific heat capacity at finite temperature $T \neq 0$. Our findings demonstrate that these physical parameters are influenced by the topological parameter, strength of WYMM and potential parameters. These results provide valuable insights into the interplay between thermodynamic properties of a quantum mechanical problem and the gravitational effects.

Development of a Machine Learning Potential to Study the Structure and Thermodynamics of Nickel Nanoclusters.

Machine learning (ML) potentials such as the Gaussian approximation potential (GAP) have demonstrated impressive capabilities in mapping structure to properties across diverse systems. Here, we introduce a GAP model for low-dimensional Ni nanoclusters and demonstrate its flexibility and effectiveness in capturing the energetics, structural diversity, and thermodynamic properties of Ni nanoclusters across a broad size range. Through a systematic approach encompassing model development, validation, and application, we evaluate the model's efficacy in representing energetics and configurational features in low-dimensional regimes while also examining its extrapolative nature to vastly different spatiotemporal regimes. Our analysis and discussion shed light on the data quality required to effectively train such models. Trajectories from large-scale MD simulations using the GAP model analyzed with data-driven models like graph neural networks reveal intriguing insights into the size-dependent phase behavior and thermomechanical stability characteristics of porous Ni nanoparticles. Overall, our work underscores the potential of ML models, which coupled with data-driven approaches serve as versatile tools for studying low-dimensional systems and complex material dynamics.

Reverse design of molecule‐process‐process networks: A case study from HEN‐ORC system

AbstractThe integrated design of the heat exchanger network (HEN) and organic Rankine cycle (ORC) system with new working fluids is a complex optimization problem. It involves navigating a vast design space across working fluid molecules, ORC processes, and networks. In this article, a new two‐stage reverse strategy is developed. The optimal HEN‐ORC configurations and operating conditions, and the thermodynamic properties of the hypothetical working fluid are identified by an equation of state (EOS) free HEN‐ORC model in the first stage. With two developed group contribution‐artificial neural network thermodynamic property prediction models, working fluid molecules are screened out in the second stage from a database containing more than 430,000 hydrofluoroolefins (HFOs). The presented method is employed in two cases, where new working fluids are found. The total annual cost of Case 1 is 12%–22% lower than the literature, and the power output of Case 2 is 5%–8% higher than the literature.

An optimal transformation method for inferring ocean tracer sources and sinks

Abstract. The geography of changes in the fluxes of heat, carbon, freshwater and other tracers at the sea surface is highly uncertain and is critical to our understanding of climate change and its impacts. We present a state estimation framework wherein prior estimates of boundary fluxes can be adjusted to make them consistent with the evolving ocean state. In this framework, we define a discrete set of ocean water masses distinguished by their geographical, thermodynamic and chemical properties for specific time periods. Ocean circulation then moves these water masses in geographic space. In phase space, geographically adjacent water masses are able to mix together, representing a convergence, and air–sea property fluxes move the water masses over time. We define an optimisation problem whose solution is constrained by the physically permissible bounds of changes in ocean circulation, air–sea fluxes and mixing. As a proof-of-concept implementation, we use data from a historical numerical climate model simulation with a closed heat and salinity budget. An inverse model solution is found for the evolution of temperature and salinity that is consistent with “true” air–sea heat and freshwater fluxes which are introduced as model priors. When biases are introduced into the prior fluxes, the inverse model finds a solution closer to the true fluxes. This framework, which we call the optimal transformation method, represents a modular, relatively computationally cost-effective, open-source and transparent state estimation tool that complements existing approaches.

Characterization and evaluation of a tray dryer with change of position: kinetics and thermodynamic properties of the process, preserving the nutraceutical properties in Golden Delicious apple slices.

The drying kinetics in apple slices between 45–55 °C was studied until reach a moisture ratio of 10±2%. 8 thin layer drying models were statistically fitted where the Midilli-Kucuk model presented the best performance, moreover its drying constant increased with the temperature, effective diffusivity was ranged from 68.16 E-10 – 2.28 E-08 m2 s-1, the Arrhenius factor and activation energy were 3.74 E-02 m2 s-1 and 28.11 kJ mol-1, the enthalpy decreased from 25.46–25.38 kJ mol-1, the entropy was ranged between (-0.2728 – -0.2730) kJ mol-1 K-1, and the Gibbs free energy increased from 112.25–114.98 kJ mol-1. The 45 °C treatment preserved the highest phenolic compounds (51.1±1.54 mg EAG 100 g-1), while the initial activity of elimination of radicals was 766.9±91.4 and 973.3±103.4 µg mg-1 according to the DPPH and ABTS methods, the antioxidant activity shows an inverse behavior to the drying temperature. This work will allow to establish the temperature, time, moisture ratio and energy to drying apple slices according to local weather or under controlled conditions.

Role of harmonic and anharmonic interactions in controlling the cooperativity of spin-crossover molecular crystals

We present a theoretical model of spin transitions in homogeneous spin-crossover (SCO) materials, based on the description of the interactions between SCO molecules by the Lennard-Jones potential in which the equilibrium distances depend on the spin states of the linked molecules. By expanding the potential to order 3 considering a homogeneous lattice spacing, we demonstrate that the present model is isomorphic with an Ising-like model combining infinite long-range “ferromagnetic-like” interactions, competing with short-range “antiferromagnetic-like” between nearest neighbors in the case of harmonic interactions. When an anharmonic contribution is included, the short-range interaction becomes dependent on the average high-spin fraction, and changes its sign along the spin transition. The thermodynamic properties of the model were first investigated analytically in mean field approximation for both harmonic and anharmonic cases, for which we clarify the conditions for obtaining gradual and first-order transitions. Moreover, we demonstrated that within this approximation, the strength of the antiferromagnetic-like interactions are insufficient to produce multistep transitions. In contrast, the resolution of the previous emerging Ising-like model by Monte Carlo simulations demonstrated the possibility of obtaining gradual, first-order and two-step transitions as a result of the antagonism between long- and short-range interactions. Overall, the obtained results demonstrate the suitability of the present theoretical model to describe cooperative SCO materials. The key message of our paper is that our model can be used to predict complex behavior of spin-crossover crystals. Published by the American Physical Society 2024

MARTINI Coarse-Grained Force Field for Thermoplastic Starch Nanocomposites.

Thermoplastic starch (TPS) is an excellent film-forming material, and the addition of fillers, such as tetramethylammonium-montmorillonite (TMA-MMT) clay, has significantly expanded its use in packaging applications. We first used an all-atom (AA) simulation to predict several macroscopic (Young's modulus, glass transition temperature, density) and microscopic (conformation along 1-4 and 1-6 glycosidic linkages, composite morphology) properties of TPS melt and TPS-TMA-MMT composite. The interplay of polymer-surface (weakly repulsive), plasticizer-surface (attractive), and polymer-plasticizer (weakly attractive) interactions leads to conformational and dynamics properties distinct from those in systems with either attractive or repulsive polymer-surface interactions. A subset of AA properties was used to parametrize the MARTINI-2 coarse-grained (CG) force field (FF) for the melt and composite systems. The missing bonded parameters of amylose and amylopectin and the bead types for 1-4 and 1-6 linked α-D glucose were determined using two-body excess entropy, density, and bond and angle distributions in the AA TPS melt. This new MARTINI-2 CG model was also compared with the MARTINI-3 model for the TPS melt. However, the requirement of a polarizable water model necessitates the use of MARTINI-2 FF for the composite system. This liquid-liquid partitioning-based FF shows freezing and compaction of polymer chains near the clay surface, further accentuated by lowering of dispersive interactions between pairs of high-covalent-coordination ring units of TPS polymers and the montmorillonite sheet. A rescaling of the effective dispersive component of TPS-MMT cross interactions was used to optimize the MARTINI-2 FF for the composite system with structural (chain size distribution), thermodynamic (chain conformational entropy and density), and dynamic (self-diffusion coefficient) properties obtained from long AA simulations forming the constraints for optimization. The obtained CG FF parameters provided excellent estimates for several other properties of the melt and composite systems not used in parameter estimation, thus establishing the robustness of the developed model.

First principles investigations on structural, electronic, optical, and thermodynamical properties of bulk and surfaces of In2CO

This study reports first-principles investigations of the structural, electronic, thermal, and optical properties of a novel material In2CO in bulk phase and slab models in (001), (100), (101), and (011) orientations to develop a fundamental understanding of its characteristics. The material appeared structurally as well as dynamically stable in the orthorhombic phase. The thermal properties demonstrated that the material's heat capacity is more temperature-sensitive than entropy and enthalpy. The electronic band structure analysis revealed that the orthorhombic phase material is a semiconductor with a narrow indirect band gap. The electronic structures modeled using the spin-orbit coupling yielded the metallic phase of the slabs except for (001) orientation. The electromagnetic absorption characteristics of the compound are also investigated to explore the material's potential in optoelectronic applications. The direction-dependent study of optical characteristics revealed that the (001) slab of the material can be an efficient infrared detector. The survey findings provide instrumental outcomes in utilizing In2CO in electronic and optoelectronic applications.

Dielectric and electrical properties of liquid crystals doped with ferroelectric nanoparticles

ABSTRACT The present work examines the impact of incorporating ferroelectric Ba0.85Sr0.15TiO3 nanoparticles (NPs) on the thermodynamic, dielectric, electrical, ionic, and electro-optical properties of 4-cyano-4’-octylbiphenyl (8CB) as Liquid Crystal (LC). The introduction of ferroelectric NPs results in a notable elevation of the nematic-isotropic phase transition temperature, which is consistent with theoretical models. Impedance spectroscopy was employed to investigate bulk and interfacial phenomena, revealing a low-frequency relaxation mode attributed to space charge polarisation. In comparison to the pure LC, the dielectric anisotropy and the DC conductivity were found to be increased in the doped samples. Furthermore, the reduction in the concentration of ions on the surface, their diffusion constant, and their mobility, coupled with a decrease in the threshold voltage, simultaneously indicate the trapping of ions by the ferroelectric NPs. The screening effect renders dispersed ferroelectric NPs an optimal solution for addressing the issue of ionic contamination and eliminating its deleterious effects.

Combustion and thermodynamics properties of erythritol tetranitrate-based energetic films composed by electrospinning nano fibers

ABSTRACT High energy composite films made from high explosives has important applications in pyrotechnics. In this study, electrostatic spraying was used to prepare energy-containing films based on 1,2,3,4-butanetetrol tetranitrate (ETN). The results show that all energy containing films are made of nanofibres. They have excellent hydrophobicity and combustion properties. In particular, monolayer films in which ETN is the main energy containing substance. Once ignited, the trace monolayer film generates a maximum pressure of 0.85 MPa and an adiabatic flame temperature of 2,855 °C. For single and double layer films, the heat of combustion can reach 9899 J/g and 11975 J/g respectively. The level of combustion heat can also be controlled by adjustment of the ETN content. The results of the thermo-properties performance evaluation show that by optimizing the nanostructure, the ETN-based energy-containing fiber membranes can meet the requirements of advanced pyrotechnic products. In particular, there is great potential in the metastable intermixed composites (MICs) field.

Investigation of the Optoelectronic, γ‐Attenuation, and Thermodynamic Properties of Novel MnGa2P3H4NO14 for Energy Applications: A DFT Study

ABSTRACTTransparent conducting oxides (TCOs) from the semiconductor family have garnered considerable interest due to the growing popularity of optoelectronic and thermodynamical applications. Our present study has presented findings on the electronic, optical, and thermodynamic characteristics of spinel oxide MnGa2P3H4NO14; using density functional theory (DFT), we utilized first‐principles calculations carried out with the Wien 2 k software package. The calculations were performed using the generalized‐gradient‐approximation plus Hubbard potential U (GGA+U) method for the doped materials. The band structure calculation reveals that the parent compound exhibits a semiconducting nature and a direct band gap of 2.9 and 1.7 eV for spin‐up and down channels, respectively. The stability of the material is assessed by evaluating its formation energies, which reveal that spinel oxide exhibits the highest stability. The thermodynamic properties are determined using the quasiharmonic Debye model, implemented in the GIBBS 2 code. Furthermore, the quasiharmonic Debye model examines the pressure and temperature dependence of all parameters related to the investigated spinel oxides. In order to evaluate the effectiveness of the radiation shielding, we computed the mass attenuation coefficient for the XCOM program that was investigated from the sample. In addition, linear attenuation, half‐value layer, and mean free path values have been evaluated. A thorough investigation into the dielectric function's optical characteristics was conducted. It has been found that the dielectric function exhibits a wide range of energy transparency. The discovery of UV‐absorbing materials with extremely narrow band gaps suggests their potential use in optoelectronic and solar cell applications. These results provide solid proof and motivation for seeking cutting‐edge optoelectronic materials and technology.

Deciphering the Evolution of Thermodynamic Properties and their Connection to the Global Kinematics of High-Speed Coronal Mass Ejections Using FRIS Model

Abstract Most earlier studies have been limited to estimating the kinematic evolution of coronal mass ejections (CMEs), and only limited efforts have been made to investigate their thermodynamic evolution. We focus on the interplay of the thermal properties of CMEs with their observed global kinematics. We implement the Flux rope Internal State (FRIS) model to estimate variations in the polytropic index, heating rate per unit mass, temperature, pressure, and various internal forces. The model incorporates inputs of 3D kinematics obtained from the Graduated Cylindrical Shell (GCS) model. In our study, we chose nine fast-speed CMEs from 2010 to 2012. Our investigation elucidates that the selected fast-speed CMEs show a heat-release phase at the beginning, followed by a heat-absorption phase with a near-isothermal state in their later propagation phase. The thermal state transition, from heat release to heat absorption, occurs at around 3(±0.3) to 7(±0.7) R⊙ for different CMEs. We found that the CMEs with higher expansion speeds experience a less pronounced sharp temperature decrease before gaining a near-isothermal state. The differential emission measurement (DEM) analysis findings, using multi-wavelength observation from SDO/AIA, also show a heat release state of CMEs at lower coronal heights. We also find the dominant internal forces influencing CME radial expansion at varying distances from the Sun. Our study shows the need to characterize the internal thermodynamic properties of CMEs better in both observational and modeling studies, offering insights for refining assumptions of a constant value of the polytropic index during the evolution of CMEs.

A Machine Learning Free Energy Functional for the 1D Reference Interaction Site Model: Towards Prediction of Solvation Free Energy for All Solvent Systems

Understanding the interactions between solutes and solvents is vital in many areas of the chemical sciences. Solvation free energy (SFE) is an important thermodynamic property in characterising molecular solvation and so accurate prediction of this property is sought after. The One-Dimensional Reference Interaction Site Model (RISM) is a well-established method for modelling solvation, but it is known to yield large errors in the calculation of SFE. In this work, we show that a single machine learning free energy functional for RISM can accurately model solvation thermodynamics in multiple solvents. A convolutional neural network is trained on solvation free energy density functions calculated by RISM for small organic molecules in approximately 100 different solvent systems. We achieve an average RMSE of 1.41 kcal/mol and an R2 of 0.89 across all solvent systems. We also compare the performance for the most and least commonly represented solvents and show that higher accuracy is generally seen with higher volumes of data, with RMSE values of 0.69–1.29 kcal/mol and R2 values of 0.78–0.97 for solvents with more than 50 data points. We have shown that machine learning can greatly improve solvation free energy predictions in RISM, while demonstrating that the methodology is generalisable across solvent systems. This represents a significant step towards a universal machine learning SFE functional for RISM.

Biothermodynamics of Hemoglobin and Red Blood Cells: Analysis of Structure and Evolution of Hemoglobin and Red Blood Cells, Based on Molecular and Empirical Formulas, Biosynthesis Reactions, and Thermodynamic Properties of Formation and Biosynthesis.

Hemoglobin and red blood cells (erythrocytes) have been studied extensively from the perspective of life and biomedical sciences. However, no analysis of hemoglobin and red blood cells from the perspective of chemical thermodynamics has been reported in the literature. Such an analysis would provide an insight into their structure and turnover from the aspect of biothermodynamics and bioenergetics. In this paper, a biothermodynamic analysis was made of hemoglobin and red blood cells. Molecular formulas, empirical formulas, biosynthesis reactions, and thermodynamic properties of formation and biosynthesis were determined for the alpha chain, beta chain, heme B, hemoglobin and red blood cells. Empirical formulas and thermodynamic properties of hemoglobin were compared to those of other biological macromolecules, which include proteins and nucleic acids. Moreover, the energetic requirements of biosynthesis of hemoglobin and red blood cells were analyzed. Based on this, a discussion was made of the specific structure of red blood cells (i.e. no nuclei nor organelles) and its role as an evolutionary adaptation for more energetically efficient biosynthesis needed for the turnover of red blood cells.