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We present the results for energy landscapes of hexapeptides obtained using interfaces to the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) program. We have used basin-hopping global optimization and discrete path sampling to explore the landscapes of hexapeptide monomers, dimers, and oligomers containing 10, 100, and 200 monomers modeled using a residue-level coarse-grained potential, Mpipi, implemented in LAMMPS. We find that the dimers of peptides containing amino acid residues that are better at promoting phase separation, such as tyrosine and arginine, have melting peaks at higher temperature in their heat capacity compared to phenylalanine and lysine, respectively. This observation correlates with previous work on the same uncapped hexapeptide monomers modeled using atomistic potential. For oligomers, we compare the variation in monomer conformations with radial distance and observe trends for selected angles calculated for each monomer. The LAMMPS interfaces to the GMIN and OPTIM programs for landscape exploration offer new opportunities to investigate larger systems and provide access to the coarse-grained potentials implemented within LAMMPS. [ABSTRACT FROM AUTHOR]

In this study, we performed a numerical investigation of the thermophysical properties of liquid (U, Zr) mixtures, which are particularly relevant in the context of hypothetical nuclear accidents and the formation of in-vessel coriums. To do so, atomistic simulations leveraging classical molecular dynamics and an interatomic potential developed for solid (U, Zr) structures are performed. Our methodology is first validated by comparing the predictions of our model for the melting temperature and the structure factors to experimental, phase diagram, and ab initio data. We then use the approach to evaluate the temperature and composition dependence of four fundamental properties in the context of coriums: density, heat capacity, compressibility, and viscosity. Systematic comparisons to the existing experimental data are performed and discussed. In particular, the viscosity of liquid (U, Zr) mixtures is investigated by comparing diffusion calculations and the Stokes–Einstein formula as well as the results obtained with the Green–Kubo methodology, empirical predictions, and experimental data. Notably, the viscosity of the mixtures is predicted to be significantly higher than that of the single-element liquids, which is unexpected and could have crucial consequences on the early stages of the formation and flow of in-vessel corium. [ABSTRACT FROM AUTHOR]

Thermal properties of materials are essential to many applications of thermal electronic devices. Density functional theory (DFT) has shown capability in obtaining an accurate calculation. However, the expensive computational cost limits the application of the DFT method for high-throughput screening of materials. Recently, machine learning models, especially graph neural networks (GNNs), have demonstrated high accuracy in many material properties' prediction, such as bandgap and formation energy, but fail to accurately predict heat capacity(C V) due to the limitation in capturing crystallographic features. In our study, we have implemented the material informatics transformer (MatInFormer) framework, which has been pretrained on lattice reconstruction tasks. This approach has shown proficiency in capturing essential crystallographic features. By concatenating these features with human-designed descriptors, we achieved a mean absolute error of 4.893 and 4.505 J/(mol K) in our predictions. Our findings underscore the efficacy of the MatInFormer framework in leveraging crystallography, augmented with additional information processing capabilities. [ABSTRACT FROM AUTHOR]

We present a detailed study on the temperature-dependent THz spectra of the polycrystalline amino acids, L-serine and L-cysteine, for wavenumbers from 20 to 120 cm−1 and temperatures from 4 to 300 K. Even though the structure of these two amino acids is very similar, with a sulfur atom in the side chain of cysteine instead of an oxygen atom in serine, the excitation spectra are drastically different. Obviously, the vibrational dynamics strongly depend on the ability of cysteine to form sulfur–hydrogen bonds. In addition, cysteine undergoes an order–disorder type phase transition close to 80 K, documented by additional specific heat experiments, with accompanying anomalies in the THz results. On increasing temperatures, well-defined vibrational excitations exhibit significant shifts in the eigenfrequencies with concomitant line-broadening yielding partly overlapping modes. Interestingly, several modes completely lose all their dipolar strength and are unobservable under ambient conditions. Comparing the recent results to the published work utilizing THz, Raman, and neutron-scattering techniques, as well as with ab initio simulations, we aim at a consistent analysis of the results ascribing certain eigenfrequencies to distinct collective lattice modes. We document that THz spectra can be used to fine-tune the parameters of model calculations and as fingerprint properties of certain amino acids. In addition, we analyzed the low-temperature heat capacity of both the compounds and detected strong excess contributions compared to the canonical Debye behavior of crystalline solids, indicating soft excitations and a strongly enhanced phonon-density of states at low frequencies. [ABSTRACT FROM AUTHOR]

Numerical methods for analyzing diffusion phenomena involving strong discontinuities and complicated interfaces are of great scientific and technical importance. In this paper, we extend the existing step-balanced random walk, which overcomes the problem of detailed balance of a random walker in three-dimensional (3D), diffusion-tensor discontinuous systems, to particle density (ρ) discontinuous systems, and introduce volumetric heat capacity C and temperature T by considering ρ as heat density, i.e., ρ = C T , to apply it to thermal problems. Two types of thermophysical simulations are demonstrated: one is steady-state heat flow due to a temperature difference at the end surfaces on a two-phase slab model unit cell with periodic boundary conditions; the other is the time variation of temperature distribution due to heat diffusion from a point heat source in a repeated two-phase slab model with no periodic boundary conditions. We see the correct behavior of heat and temperature expected in 3D discontinuous systems composed of two phases with anisotropic thermal conductivity. The applicability to problems other than pure diffusion and the limitations of the method are also discussed. [ABSTRACT FROM AUTHOR]

Magnetocaloric properties of hexagonally structured Mn 5 − x Fe x Ge 3 (x = 0.15 , 0.3, and 0.5) alloys have been investigated using DC magnetization and heat capacity measurements. The maxima of entropy change, − Δ S m max ∼ 5.04 (5.57) J/kg K, along with an adiabatic temperature change of Δ T a d max ∼ 5.05 (7.25) K was observed for x = 0.15 (0.5) at an applied magnetic field H = 5 T. With the scaling analysis of − Δ S m , the rescaled curves collapse onto a single universal curve anticipated by the mean-field theory, revealing a second-order type of magnetic transition. Furthermore, − Δ S m max follows a power law of H n with n = 0.597 (3) , 0.591(3), and 0.586(3) for Mn 5 − x Fe x Ge 3 (x = 0.15 , 0.3, and 0.5) alloys, respectively. The refrigerant capacity (RC) is increased from 400 J/kg (for x = 0.15) to 420 J/kg (for x = 0.5) with Fe doping in Mn 5 Ge 3. Moreover, the coefficient of refrigerant performance (CRP) enhances with Fe doping from 0.06 (for x = 0.15) to 0.1 (for x = 0.5). Thus, high RC and reasonable CRP values for earth-abundant Mn-based Mn–Fe–Ge alloys promise the potential to replace the high-cost rare-earth (Gd) and heavy metal-based metallic magnetocaloric systems for use in environment-friendly magnetic refrigeration technology. [ABSTRACT FROM AUTHOR]

The exponential-6 (exp-6) potential is commonly used to model fluids at high densities. In this paper, I propose a new equation of state (EOS) in the form of an analytical expression for the excess Helmholtz free energy of an exp-6 fluid. The EOS is based on extensive Monte Carlo simulations and therefore combines the excellent accuracy of the simulations with the numerical efficiency of a polynomial expression. The mean relative error in compressibility factor and internal energy is 0.14% and 0.25% respectively, which is a significant improvement over statistical mechanical theories. The EOS was implemented into a thermochemical code in order to optimize gas parameters and evaluate its performance on pure gas data, shock compression and detonation properties. Predicted gas densities, heat capacities and speed of sound for pure gases were generally within experimental uncertainties at pressures up to 1 GPa and temperatures above 300 K. For polar molecules, a simple free energy correction was introduced which greatly improved accuracy at low temperature. Calculated shock Hugoniots showed excellent agreement with experimental values up to 150 GPa and 10 000 K, and the detonation performance was accurately predicted for a number of different types of explosives. [ABSTRACT FROM AUTHOR]

Contrary to the case of solids and gases, where Debye theory and kinetic theory offer a good description for most of the physical properties, a complete theoretical understanding of the vibrational and thermodynamic properties of liquids is still missing. Liquids exhibit a vibrational density of states (VDOS) which does not obey Debye law, and a heat capacity which decreases monotonically with temperature, rather than growing as in solids. Despite many attempts, a simple, complete and widely accepted theoretical framework able to formally derive the aforementioned properties has not been found yet. Here, we revisit one of the theoretical proposals, and in particular we re-analyze the properties of liquids within the soft-potential model, originally formulated for glasses. We confirm that, at least at a qualitative level, many characteristic properties of liquids can be rationalized within this model. We discuss the validity of several phenomenological expressions proposed in the literature for the density of unstable modes, and in particular for its temperature and frequency dependence. We discuss the role of negative curvature regions and unstable modes as fundamental ingredients to have a linear in frequency VDOS. Finally, we compute the heat capacity within the soft potential model for liquids and we show that it decreases with temperature, in agreement with experimental and simulation data. [ABSTRACT FROM AUTHOR]

In this paper, we apply a theoretical model for fluid state thermodynamics to investigate simulated water in supercooled conditions. This model, which we recently proposed and applied to sub- and super-critical fluid water [Zanetti-Polzi et al., J. Chem. Phys. 156(4), 44506 (2022)], is based on a combination of the moment-generating functions of the enthalpy and volume fluctuations as provided by two gamma distributions and provides the free energy of the system as well as other relevant thermodynamic quantities. The application we make here provides a thermodynamic description of supercooled water fully consistent with that expected by crossing the liquid–liquid Widom line, indicating the presence of two distinct liquid states. In particular, the present model accurately reproduces the Widom line temperatures estimated with other two-state models and well describes the heat capacity anomalies. Differently from previous models, according to our description, a cluster of molecules that extends beyond the first hydration shell is necessary to discriminate between the statistical fluctuation regimes typical of the two liquid states. [ABSTRACT FROM AUTHOR]

We report on efforts to improve the speed of low-G far-infrared transition-edged-sensed bolometers. We use a fabrication process that does not require any dry etch steps to reduce heat capacity on the suspended device and measure a reduction in the detector time constant. However, we also measure an increase in the temperature-normalized thermal conductance (G) and a corresponding increase in the noise-equivalent power (NEP). We employ a new near-IR photon-noise technique using a near-IR laser to calibrate the frequency-domain multiplexed AC system and compare the results to a well-understood DC circuit. We measure an NEP white noise level of 0.8 aW/rtHz with a 1/f knee below 0.1 Hz and a time constant of 3.2 ms. [ABSTRACT FROM AUTHOR]

G-quadruplexes are four-stranded DNA structures that have been found in the cell and are thought to act as elements of control in genomic events. The measurements of the thermodynamic stability, ΔG, of G-quadruplexes shed light on the molecular forces involved in the stabilization of these structures. In thermodynamic studies, the differential heat capacity, ΔCP, of the folded and unfolded states of a G-quadruplex is a fundamental property that describes the temperature dependences of the differential enthalpy, ΔH, entropy, ΔS, and free energy, ΔG. Despite its recognized importance, the ΔCP of G-quadruplex unfolding has not been measured directly. Here, we use differential scanning calorimetry to evaluate changes in heat capacity, ΔCP, accompanying the unfolding transitions of G-quadruplexes formed by modified DNA sequences from the promoter regions of the c-MYC, VEGF, and Bcl-2 oncogenes. The average value of ΔCP is 0.49 ± 0.12 kcal mol−1 K−1. Our analysis revealed that disregarding ΔCP leads to significant errors in extrapolated values of the differential enthalpy, ΔH, and entropy, ΔS, of the folded and unfolded DNA conformations. Although the compensation between ΔH and ΔS weakens the effect of ΔCP on the differential free energy, ΔG, neglecting ΔCP may still result in relative errors in ΔG extrapolated to room temperature as great as 140%. We emphasize the importance of proper consideration of the effect of ΔCP in conformational studies of guanine-rich DNA molecules. [ABSTRACT FROM AUTHOR]

In a recent paper, Mandelis et al. [J. Appl. Phys. 133, 055102 (2023)] describe a photothermal methodology and a new inversion technique which, when applied to a heterogeneous material, is claimed to allow a simultaneous reconstruction of the depth profiles of thermal conductivity and density (assuming that the specific heat is a known constant). In this Comment we recall that, for the thermophysical configuration considered, the thermal conductivity and volumetric heat capacity profiles cannot be identified simultaneously because they are fully correlated. The exposed problem exhibits unconditional non-identifiability leading to the non-uniqueness of the solution. The apparent success of the inversion tests does not preclude the fact that, for any (apparently) optimal solution, an infinite multiplicity of equally satisfactory pairs of conjugate profiles can be built. The simultaneous identification of the density and thermal conductivity profiles is here an unsolvable inverse problem. [ABSTRACT FROM AUTHOR]

Compositional tuning of magnetic properties to provide technologically useful results is in the forefront of research in complex oxides. Taking advantage of the highly sensitive nature of magnetism in 6H barium ruthenates (Ba3MRu2O9, M = transition metals or rare earth ions) to composition, we have carried out M-site dual doping by 50% each of Co and Mn. The high pressure and high temperature synthesized sample of 6H Ba3Co0.5Mn0.5Ru2O9 shows giant exchange bias (5.71 kOe at 5 K and 50 kOe cooling field) and huge coercivity (9.42 kOe at 5 K) at low temperature along with Griffiths phase like behavior in the 136 K < T < 260 K temperature range. The presence of ferromagnetic (FM) clusters in a non-collinear antiferromagnetic (AFM) background for temperature below 136 K is assumed. These FM clusters extend above 136 K to persist until 260 K, and the system finally reaches the paramagnetic (PM) state closer to room temperature. The exchange bias phenomena diminish above 20 K and this could be correlated with the peculiar nature of magnetic isotherms above and below this temperature. The transition at 136 K is regarded as AFM short-range ordering from ac and dc magnetization studies and heat capacity measurement. The presence of short-range interactions at temperatures until the PM region forms the basis of Griffiths phase like behavior in this sample. [ABSTRACT FROM AUTHOR]

This study introduces machine learning (ML) algorithms to predict hydrogen (H 2) thermodynamic properties for geological storage, focusing on its mixtures with natural gas, nitrogen (N 2), and carbon dioxide (CO 2). Employing 1167 data samples, this research utilizes multiple linear regression (MLR), random forest (RF), gradient boosting (GB), and decision tree (DT) models, enhanced by sensitivity analysis for feature engineering. GB model's superior accuracy and efficiency over conventional statistical linear regression methods. The finding reveals that the GB model achieves superior performance, with an R2 value of 0.9998 for thermal capacity and the lowest mean absolute error (MAE)/root mean square error (RMSE) across all H 2 properties—density (1.51%, 2.06 kg/m3), viscosity (0.000078%, 0.000117 cp), thermal conductivity (0.000427%, 0.000849 W/m.K), and thermal capacity (8.79%, 26.06 J/g.K). Moreover, this ML-based approach not only demonstrates remarkable accuracy and efficiency but also suggests the potential of smart paradigms to further enhance the safety and transportability of underground hydrogen storage projects. Ultimately, this work will help the reservoir simulation at field scale to be more robust and reliable. [Display omitted] • Machine learning employed in the prediction of hydrogen's thermodynamic properties. • Four advanced ML-based models constructed by variables such as pressure, temperature, and hydrogen fraction. • Gradient boosting algorithm comparatively showed the highest accuracies. • ML achieved the lowest MAE/RMSE values for viscosity 0.000078/0.000117. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the quantum corrected black hole’s thermodynamic properties in this paper. To assess the local and global thermodynamic stability, we compute a number of indicators such as the geometric mass, heat capacity, Hawking temperature, thermodynamic temperature, Gibbs free energy, and energy emission. The fundamental law of thermodynamics determines the temperature of the black hole. Our results ensure the overall thermal stability of the black hole solution. Our results for Gibbs free energy and heat capacity show the phase transition behavior of the black hole. [ABSTRACT FROM AUTHOR]

The development of wearable heat supply textiles in cold conditions utilizing the photothermal conversion effect is crucial for the advancement of wearable thermal management textiles that do not require any power supply connection or other external energy input. Here, a dual gelation strategy under gravity‐enhanced orientation is proposed to construct super‐strong bacterial cellulose (BC) aerogel fiber using BC as the matrix material and hydroxylated carbon nanotubes (HCNT) as the photothermal conversion material. Under the assistance of orientation property and dual network structure with soft–hard synergy, the silanized BC/HCNT (SBT) aerogel fiber has rich network, tensile strength up to 26.0 MPa, flexibilityand knittability. Thanks to the enhanced network backbone, after the introduction of the phase change material eicosane in SBT aerogel fiber (SBTE), the SBTE fiber achieves high enthalpy of 105 J g−1, low leakage, storage stabilityand super‐strong and tough mechanical properties of 23.9 MPa and 8.7 MJ m−3, while maintaining flexibility, knittabilityand hydrophobicity. The textile woven by SBTE fiber also exhibits a long‐lasting heat supply capacity at low temperatures and under real‐world conditions. Therefore, the finely designed SBTE fiber has the potential to be used in solar‐driven wearable heat supply textiles in cold weather. [ABSTRACT FROM AUTHOR]

The continuous updating and iteration of electronic devices brings about a significant accumulation of heat. It is urgent to enhance the thermal properties of polymer‐based composites to alleviate the heat dissipation problem in the microelectronics industry. In this paper, the hot drawing process was introduced to increase the crystallinity of ultra‐high molecular weight polyethylene (UHMWPE) fiber and improve its thermal conductivity. The ultra‐high molecular weight polyethylene fiber/epoxy resin (UHMWPE fiber/Epoxy) composites with high thermal conductivity were prepared by compositing UHMWPE fiber with epoxy resin under vacuum conditions. Due to the good crystallinity of the UHMWPE fiber (86%), an efficient thermal conduction path is provided for phonons in the axial direction along the fibers. The results show that the thermal conductivity of the composites reaches a maximum of 3.51 W/mK (in‐plane), which is 17.47 times higher than that of the epoxy resin (0.19 W/mK). The thermography pictures indicate that the composites have better heat transfer capacity with an increase in the draw ratio (λ). In addition, the composites also have the characteristics of low density and low electrical conductivity. These researches will provide a new idea for the preparation of all‐polymer composites with high thermal properties. Highlights: A hot drawing process was introduced to increase the crystallinity of UHMWPE fiber for improving thermal conductivity.High crystallinity facilitates the reduction of phonon scattering and the transmission of thermal energy by phonons.The obtained polymer composites exhibit an ultra‐high in‐plane thermal conductivity. [ABSTRACT FROM AUTHOR]

The avian vampire fly is an invasive species on the Galapagos Islands, where its hematophagous larvae utilize nestling birds as hosts. It poses a serious threat to populations and species of Darwin finches and other avian species. Prior studies suggest that the avian vampire fly larvae develop more rapidly in nests of small tree finches compared to sympatric green warbler finch nests. Here we investigate factors that may differentially influence larval growth in the two host species, including nest microclimate and nestling diet. We collected nest base temperature and humidity data as proxies for nest microclimate. As indicators of dietary composition and quality, we measured stable isotope δ13C and δ15N composition of nestling blood, used the C:N ratios as an indicator of relative protein content, and assessed the amino acid composition of the blood. The hematophagous larvae living off nestling blood were analyzed for the same parameters except amino acid composition. The effect of nest base humidity on nest base temperature significantly depended on bird species: at low humidity levels nest base temperature was higher in the small tree finch, and declined in both species as nest base humidity increased, which suggests higher stable heat capacity of small tree finch nests. The effect of age group based on the predicted onset of thermoregulation was marginally significant. Nest base temperatures were significantly higher in small tree finch nests during the predicted female brooding period before fully effective thermoregulation. Stable isotope δ13C levels were significantly higher in the blood of small tree finch nestlings compared to warbler finch nestlings, suggesting a difference in nestling food composition and source, while. δ15N levels were similar. The C:N ratios and amino acid composition of nestling blood were not significantly different between the two species, suggesting similar dietary quality. Thus, the faster development of larvae in small tree finch nests may be due to higher nest base temperatures during the early nestling phase rather than host blood quality parameters. [ABSTRACT FROM AUTHOR]

The article discusses the induction coil setup and fabrication process for self-folding structures. The induction heating system is crucial for the self-folding process and its parameters are determined by the coil's inductance, electrical capacity, and current supplied. The fabrication process involves several steps, including cutting the copper sheet, applying silicone tape, and folding the PVC film. The article also discusses the modeling of PVC film shrinkage and induction heating. Overall, the article provides detailed information on the technical aspects of self-folding structures. [Extracted from the article]

The solvothermal reaction of FeCl2 ⋅ 4H2O and H4TBC[4] in a basic dmf/EtOH solution affords an [FeIII18] Keplerate conforming to a stellated cuboctahedron. Magnetic and heat capacity measurements reveal spin frustration effects arising from the high symmetry. A crossover between inverse and direct magnetocaloric effects is observed at ~10 K for applied‐field changes lower than 3 T. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of FeCl2 ⋅ 4H2O and H4TBC[4] in a basic dmf/EtOH solution affords an [FeIII18] Keplerate conforming to a stellated cuboctahedron. Magnetic and heat capacity measurements reveal spin frustration effects arising from the high symmetry. A crossover between inverse and direct magnetocaloric effects is observed at ~10 K for applied‐field changes lower than 3 T. [ABSTRACT FROM AUTHOR]

This study solves the radial Schrödinger wave equation (RSWE) with the improved Rosen–Morse (IRM) potential constrained by an electromagnetic field. Energy eigenvalues are derived using the parametric Nikiforov–Uvarov method and Pekeris approximation. The internal partition function, isobaric molar heat capacity formula, and magnetization model are then deduced from the equation governing pure vibrational energy states. These analytical models are applied to several pure substances, specifically Br2 (X 1Σg+), BrF (X 1Σ+), ICl (X 1Σg+), and P2 (X 1Σg+) molecules. Numerical approximations of the energy eigenvalues for these molecules closely match their exact values. The isobaric molar heat capacity expression yields mean percentage absolute deviations of 1.6585%, 0.9162%, 1.2193%, and 0.7232% when compared against experimental data for Br2 (X 1Σg+), BrF (X 1Σ+), ICl (X 1Σg+), and P2 (X 1Σg+), respectively. These results align well with other heat capacity models in existing literature. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of FeCl2 ⋅ 4H2O and H4TBC[4] in a basic dmf/EtOH solution affords an [FeIII18] Keplerate conforming to a stellated cuboctahedron. Magnetic and heat capacity measurements reveal spin frustration effects arising from the high symmetry. A crossover between inverse and direct magnetocaloric effects is observed at ~10 K for applied‐field changes lower than 3 T. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of FeCl2 ⋅ 4H2O and H4TBC[4] in a basic dmf/EtOH solution affords an [FeIII18] Keplerate conforming to a stellated cuboctahedron. Magnetic and heat capacity measurements reveal spin frustration effects arising from the high symmetry. A crossover between inverse and direct magnetocaloric effects is observed at ~10 K for applied‐field changes lower than 3 T. [ABSTRACT FROM AUTHOR]

During the transportation of hydrogen-blended natural gas (HBNG) through the natural gas pipeline network, the accuracy of the physical property model for real gas greatly influences the reliability of aerodynamic performance of compressor systems and the hydrothermal characteristics of pipeline networks. In this study, the adaptability of various equations of state (EOS) in predicting physical property parameters including compressibility factor, enthalpy difference, entropy difference, specific heat capacity, specific heat ratio and viscosity of natural gas (NG) and HBNG is evaluated based on the experimental data and NIST REFPROP firstly. The properties calculated using NIST REFPROP are compared with those from the EOSs, such as cubic EOSs (Redlich–Kwong EOS (RK), Soave–Redlich–Kwong EOS (SRK), Peng–Robinson EOS (PR)) and Soave-Benedict-Webb-Rubin (BWRS) EOS. After confirming the reliability of NIST REFPROP as the calculation benchmark, the accuracy of the four EOSs in calculating the physical properties of HBNG is assessed within the temperature range of 250∼350 K, pressure range of 1∼25 MPa, and hydrogen doping ratio of 0%–30%. Besides, the mixing rules of different equations of state (EOSs) are compared based on the NIST REFPROP calculation results. The results indicate that, except for specific heat capacity calculation, the mixing rule has little influence on the prediction accuracy of cubic EOS models, and the maximum calculation error between different mixing rules of the same EOS model does not exceed 0.5%. Under specific conditions, the traditional mixing rule exhibits better prediction accuracy and can be prioritized due to its simplicity. Furthermore, the pressure has a significant impact on the accuracy of EOS models, with the prediction accuracy decreasing as the pressure increased. The influence of temperature on the prediction accuracy is less significant than that of pressure. Generally, lower temperatures exhibit lower prediction accuracy, while higher temperatures show higher prediction accuracy. Among the cubic EOS models, the RK equation performs better than the SRK and PR EOS models. While the cubic EOSs show minimal differences in predicting specific heat ratio with an average relative error below 1%, the RK EOS shows significant advantages in predicting other physical parameters. The simple structure of RK EOS meets the calculation requirements for HBNG engineering. The comprehensive comparisons reveal that, the BWRS EOS has higher accuracy in predicting various physical properties parameters, with the maximum average relative error not exceeding 5% for each physical property parameter, and its stability is also better compared to the cubic EOSs. The further analysis shows that, the calculation of viscosity is influenced not only by the EOS but also by the viscosity model. When calculating viscosity using the LU-Model, the PR EOS provides the most accurate results. In contrast, when utilizing the LGE-Model or LBC-Model, the BWRS EOS demonstrates superior accuracy compared to other EOSs. • Mixing rules slightly effect state equations' accuracy across different x-H2, besides heat capacity calculations. • Unlike other parameters, the viscosity calculation depends on both the viscosity model and the equations. • Apart from viscosity calculations, Redlich-Kwong equation performs the best among the cubic state equations. • The Benedict-Webb-Rubin-Starling equation is more accurate than the cubic state equations overall. • The impact of pressure on equations' accuracy for hydrogen-blended natural gas is more obvious than that of temperature. [ABSTRACT FROM AUTHOR]

Inspired by the natural thermal charring capacity of lacquer tree bark, a novel halogen-free, bio-based and two-component synergistic flame retardant system has been constructed by introducing transition metal (Fe3+)-modified tannic acid (TA) as char source and ammonium polyphosphate (APP) as acid source, which was employed for overcoming the severe flammability problem for silicone rubber (SR). By systematically investigating the effect of APP/TA@Fe system on the flame retardancy of SR composites, it has been found that when 40 mass% APP and TA@Fe in a ratio of 3:1 are added, the limited oxygen index (LOI) and vertical combustion tests of SR composites can reach 30% and UL-94 V-0 rating with a rapid self-extinguishing capacity. Through the comprehensive analysis of the residues of SR composites after complete burning, a gas/condensed flame retardant mechanism is primarily proposed in detail. Among these, the ammonia and water vapor released by the decomposition of APP and TA@Fe during combustion can dilute the combustible gases and tannic acid will act via the free radicals scavenging ability. Besides, the continuous, intumescent and dense charring residues from the thermal interaction between APP and TA will exert a prominent role in restricting the heat/mass exchange process and inhibiting the SR matrix from further flame attacking. Surprisingly, the mechanical strength of SR system is attained even if the combination of APP and TA@Fe is blended. Consequently, this article has developed a bionic, eco-friendly and effective approach to settle the flammability problem of SR and broaden their applications in the fields of construction and decoration materials. [ABSTRACT FROM AUTHOR]

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C4(MIm)2][NTf2]2) has been studied over the temperature range from 6 to 350 K by adiabatic calorimetry. In the above temperature interval, this compound has been found to form crystal, liquid, and supercooled liquid. For [C4(MIm)2][NTf2]2, the temperature of fusion T°fus = (337.88 ± 0.01) K has been determined by the fractional melting experiments, the enthalpy of fusion ΔfusH° = (52.79 ± 0.28) kJ mol−1 has been measured using the calorimetric method of continuous energy input, and the entropy of fusion ΔfusS° = (156.2 ± 1.7) J K−1 mol−1 has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity Cp°(T), the enthalpy [H°(T) − H°(0)], the entropy S°(T) and the Gibbs free energy [G°(T) − H°(0)] have been calculated on the basis of the experimental data for the temperature range up to 350 K. The results have been discussed and compared with those available in the literature and in the NIST Ionic Liquids Database (ILThermo) for monocationic ionic compounds. [ABSTRACT FROM AUTHOR]

Shallow geothermal energy (SGE) is a widely prevalent geological resource underground, and its utilization offer significant energy conservation and emission reduction benefits, contributing to the achievement of carbon neutrality goals. Assessing the development potential of regional SGE can ensure sustainable development of these resources and prevent adverse effects induced by overexploitation. Jiangsu Province, a developed region in the eastern coastal area of China, has a strong demand for cooling and heating in urban buildings. The primary form of utilizing SGE in this area is through vertical ground source heat pumps (VGSHP). Based on the analysis of the impact of regional geological conditions on the development of SGE, this study specifically evaluated the suitability of developing SGE through VGSHP. After excluding areas unsuitable for development, the heat exchange capacity, heating or cooling area per unit area, and energy conservation and emission reduction benefits of VGSHP were calculated. The results indicate that the area suitable and moderately suitable for developing SGE through VGSHP in Jiangsu Province amounts to 76,453 km2. The total heat exchange capacity for summer is 1.21 × 109 kW, which can provide cooling for an area of 1.21 × 1010 m2. The total heat exchange capacity for winter is 8.70 × 108 kW, which can provide heating for an area of 1.09 × 1010 m2. The annual available resource amount is 2.68 × 1012 kWh, equivalent to 3.30 × 108 tons of standard coal, and a CO2 reduction of 7.86 × 108 tons. [ABSTRACT FROM AUTHOR]

The exceptional properties of high-grade graphene make it an ideal candidate for thermal dissipation and heat exchange in energy applications and nanofluid development. Here, we present a comprehensive study of few-layer graphene (FLG) nanofluids prepared in an industrial context. FLG nanofluids were synthesized through an ultrasound-assisted mechanical exfoliation process of graphite in water with a green solvent. This method produces FLG of high structural quality and stable nanofluids, as demonstrated by electron microscope, dynamic light scattering and ζeta potential analyses. Thermal conductivity measurements of FLG-based nanofluids were conducted in the temperature range of 283.15 K to 313.15 K, with FLG concentrations ranging from 0.005 to 0.200% in wt. The thermal conductivity of FLG nanofluids is up to 20% higher than water. The modeling of nanofluid thermal conductivity reveals that this enhancement is supported by the influence of the thermal resistance at the FLG interface, and the content, average dimensions and flatness of FLG sheets; this latter varying with the FLG concentration in the nanofluid. Additionally, the density and heat capacity of FLG suspensions were measured and compared with theoretical models, and the rheological behavior of FLG nanofluids was evaluated. This behavior is mainly Newtonian, with a weak 5% viscosity increase. [ABSTRACT FROM AUTHOR]

We explore the thermal properties of a system including a single-mode cavity interacting with a two-level atom at temperature T under the effect of the Stark shift. Thus, the partition function and then the thermal density matrix of the atom-field system will be needed. Using the generators of the s u (1 , 1) algebra, we first compute the total excitation number which commutes with the Hamiltonian of the system. Considering the total excitation number, the Hamiltonian is represented by a block diagonal matrix. We solve exactly our model and calculate the energy eigenvalues and corresponding eigenstates. We analyze the fidelity as numerical criterion of the closeness of the thermal atom-cavity system at two temperatures. The effect of the Stark shift coefficients on the fidelity can be studied. Moreover, we will examine the thermodynamical properties of the thermal atom-field system using the Helmholtz free energy, entropy, internal energy and heat capacity. The dependence of the temperature and Stark shift parameters on the thermodynamical properties will be discussed. [ABSTRACT FROM AUTHOR]

We calculate the phase diagrams and predict the temperature dependence of the thermodynamic quantities at high pressures for the solid – liquid and solid – solid transitions in n-paraffins. This calculation is performed by fitting the phase line equations as obtainedfrom the Landau model to the experimental data from the literature. On thebasis of the Landau model, phase diagram of the solid – solid transition ispredicted at 0.1 MPa for the binary mixtures of n-tridecane + (n-hexane and cyclohexane).For the calculation of the heat capacity the extended mean field is employedfor the n-paraffins studied here. We find that our calculated phase diagrams explain the observed behaviour of the liquid – solid transitions at high pressures in those binary mixtures. Our phase diagrams predicted at 0.1 MPa and our predictions for the thermodynamic quantities can be compared with the experiments for those binary mixtures. [ABSTRACT FROM AUTHOR]

• Screening non-fluorinated refrigerants with low GWP and reduced flammability. • Performance criterion characterizing heating capacity for low-charge heat pumps. • The most attractive refrigerants were identified through decision-making techniques. • DME-CO 2 mixtures resulted in improvements in efficiency and levelized cost of heat. • Further investigations were recommended on mixtures with DME, Propylene and CO 2. The study investigated the characteristics of different natural refrigerants and their mixtures in a residential heat pump with low refrigerant charge. Three main evaluation criteria were utilized for comparing different mixtures: Coefficient of Performance (COP), Volumetric Heating Capacity (VHC), and a newly proposed indicator, the heating capacity at charge limit. Propane was used as a reference refrigerant. It was found that some mixtures significantly improved both COP and the heating capacity at charge limit while maintaining similar volumetric heating capacity and operating conditions. Alternative multi-criteria decision-making techniques were adopted to rank the best refrigerant mixtures. Mixtures rich in Dimethyl Ether (DME), such as DME-CO 2 [0.96-0.04] and DME-Propylene [0.75-0.25] were found consistently among the best options. Those were followed by Propylene-rich mixtures such as Propylene-CO 2 , Propylene-Isobutane and Propylene-Butane. The levelized cost of heat (LCOH) could be improved by up to 12 %. To accelerate the transition to natural refrigerants, without compromises on efficiency and costs, further research and certification activities on non-fluorinated refrigerants based on Dimethyl Ether (R-E170), CO 2 (R-744) and Propylene (R-1270) are recommended. [ABSTRACT FROM AUTHOR]

Thermal and electrical properties were investigated for five nominally phase‐pure high entropy carbide ceramics. The compositions (Hf0.2Nb0.2Ta0.2Ti0.2Zr0.2)C, (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C, (Hf0.2Mo0.2Ta0.2Ti0.2Zr0.2)C, (Hf0.2Ta0.2Ti0.2W0.2Zr0.2)C, and (Hf0.2Mo0.2Ti0.2W0.2Zr0.2)C were synthesized by carbothermal reduction of oxides. The thermal diffusivity and heat capacity were measured from room temperature to 1800°C. The room temperature thermal conductivity ranged from 5.1 W/mK for (Hf0.2Mo0.2Ti0.2W0.2Zr0.2)C to 9.0 W/mK for (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C. The thermal conductivity increased over the temperature range with maximum conductivities of 19.6 W/mK measured for (Hf0.2Mo0.2Ta0.2Ti0.2Zr0.2)C to 29.7 W/mK for (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C at 1800°C. The electron contribution to thermal conductivity calculated from measured electrical resistivity varied from 41% to 52% of the total thermal conductivity. The tungsten and molybdenum containing compositions had higher phonon contributions while the niobium and chromium containing compositions had nearly equal electron and phonon contributions to thermal conductivity. [ABSTRACT FROM AUTHOR]

This article discusses the thermodynamics of temperature-gated ion channels, specifically focusing on thermoTRPs (transient receptor potential channels). The authors analyze the temperature sensitivity of these channels and propose different thermodynamic models to explain their temperature gating behavior. They suggest that the assumption of a constant, temperature-independent heat capacity difference (ΔCp) might not be accurate and explore the implications of temperature-dependent ΔCp on the temperature activation curves of thermoTRPs. The authors also discuss the possibility of unfolding as a mechanism in thermoTRP temperature gating and propose further simulations and analysis to better understand the thermodynamics of these channels. [Extracted from the article]

Bose–Einstein and Fermi–Dirac statistics for finite systems have been developed using a simple generic entropy definition. The exact entropy derivatives (properties) were obtained with posterior bosons and fermions adjustment for finite systems. The usual thermodynamic limits are also considered for comparison. Some applications to two-level systems were considered to obtain energy, heat capacity, chemical potential, magnetization, and susceptibility for fermion finite systems. Energy and magnetization reach a minimum, and their derivatives, such as heat capacity, chemical potential, and susceptibility, become zero at a non-null temperature, a characteristic of finite systems. This non-null temperature is given by the inverse of the harmonic series as a function of the system size. The exact limit for low temperatures regarding finite systems was carefully considered to show the remarkable difference between finite and infinite (thermodynamic limit) systems. [ABSTRACT FROM AUTHOR]

Metallic glasses are amorphous metals that are supercooled to a frozen, glassy state and lack long-range order, in contrast to conventional metal structures. The lack of a well-ordered structure largely contributes to the unique properties exhibited by these materials. However, their synthesis and processability are defined and thereby constrained by a plethora of thermal and mechanical parameters. Therefore, their broader utilization in the scientific field and particularly in the related industry is somewhat hindered by the limitations related to preparing them in higher amounts. This may be overcome by changing the approach of metal glass formation to a bottom-up approach by utilizing solid-state plasma techniques, such as spark plasma ablation. Another important aspect of amorphous metals, inherently related to their non-equilibrium metastable nature, is the necessity to understand their thermal transformations, which requires unconventional thermal analysis methods. Therefore, this minute review aims to highlight the most important conceptual parameters behind configuring and performing conventional and advanced thermal analysis techniques. The importance of calorimetry methods (differential and fast scanning calorimetry) for the determination of key thermal properties (critical cooling rate, glass-forming ability, heat capacity, relaxation, and rejuvenation) is underscored. Moreover, the contributions of thermomechanical analysis and in situ temperature-dependent structural analysis are also mentioned. Namely, all of the mentioned temperature-dependent mechanical and structural analyses may give rise to the discovery of new glass systems with low critical cooling rates. [ABSTRACT FROM AUTHOR]

Erbium-substituted bismuth oxide with a composition of Bi1.6Er0.4O3 was synthesized by the solid-phase reaction method. The compound is shown to have a cubic structure, space group Fm3m. The standard enthalpy of formation of Bi1.6Er0.4O3 was determined from the measured enthalpies of dissolution of Bi2O3, ErCl3, and Bi1.6Er0.4O3 in a 2 M HCl solution: ΔfH0(Bi1.6Er0.4O3(s)) = −819.0 ± 6.4 kJ/mol. The lattice enthalpy for the compound was calculated using the Born–Haber cycle: ΔlatH0(Bi1.6Er0.4O3(s)) = −13 227 kJ/mol. [ABSTRACT FROM AUTHOR]

The heat capacity of zinc tungstate was determined by relaxation calorimetry in the range of ~2.6–40 K. The heat capacity was extrapolated to zero temperature, and the characteristic Debye temperature at zero temperature was determined. The experimental heat capacities presented in the literature were estimated. The values of thermodynamic functions in the range 0–301 K were refined. [ABSTRACT FROM AUTHOR]

The heat capacity of palladium bis-hexafluoroacetylacetonate (Pd(C5HF6O2)2; CAS no. 64916-48-9) is measured adiabatically in the range of 6.088–307.596 K. The obtained data are used to calculate thermodynamic functions (entropy, increment of enthalpy, reduced Gibbs energy) in the range of 0–310 K. The functional behavior of the heat capacity exhibits an anomaly in the range of 145–285 K. The anomaly has a maximum at a temperature of T ≈ 225 K, indicating a second-order phase transition in this range of temperatures. Anomalous contributions to entropy and enthalpy are calculated. [ABSTRACT FROM AUTHOR]

The temperature dependence of the heat capacity of the sixth generation carbosilane dendrimer with terminal trimethylsilylsiloxane groups was determined by high-precision adiabatic vacuum calorimetry in the temperature range 6–318 K and differential scanning calorimetry in the range 300–600 K. Anomalous changes in the heat capacity were discovered in the range T = 179–200 K due to devitrification of the dendrimer and in the range 380–450 K due to the nanoscale effect characteristic of dendrimers of high generations. The thermal stability of the compound was studied by thermogravimetric analysis, and the temperature of the start of thermal destruction was found to be 600 K. The experimental data obtained were used to calculate the standard thermodynamic functions of the dendrimer for the range from T → 0 to 600 K for various physical states, as well as the standard entropy of its formation in the devitrified state at T = 298.15 K. [ABSTRACT FROM AUTHOR]

The heat capacity of copper bis-dipivaloylmethanate complex (Cu(C11H19O2)2 or Cu(dpm)2; CAS no. 14040-05-2) in the 5.440–313.271 K range of temperatures is measured via adiabatic calorimetry. The functional behavior of the heat capacity in the studied range of temperatures does not exhibit any anomaly that could be attributed to phase transitions. The heat capacity data are used to calculate entropy, enthalpy increment, and reduced Gibbs energy in the 0–310 K range of temperatures. Based on this analysis, a universal description of heat capacity is proposed for metal dipivaloylmethanates in a wide range of temperatures. The description can be used to calculate the thermodynamic characteristics of objects from this isoligand group of metal beta-diketonates that have yet to be studied. [ABSTRACT FROM AUTHOR]

The temperature dependence of the heat capacity of betamethasone valerate in the range from 5.5 to 346 K was measured for the first time by precise vacuum adiabatic calorimetry. The thermodynamic functions of betamethasone valerate, namely, heat capacity, enthalpy H°(T) – H°(0), entropy S°(T) – S°(0), and Gibbs function G°(T) – H°(0) were determined for the temperature range from T → 0 to 350 K based on the experimental data. The thermal expansion coefficients were determined by low temperature powder X-ray diffractometry. [ABSTRACT FROM AUTHOR]

The temperature dependence of the heat capacity of Y2Ti2O7 and Eu2Ti2O7 with a pyrochlore structure in the temperature range of 7–1800 K has been studied. The existence of a small shallow anomaly of the heat capacity of europium titanate in the range of 10–60 K was confirmed. The thermodynamic properties (entropy, enthalpy change, and reduced Gibbs energy) were calculated. Based on the results of calculation of the Gibbs energy of formation of the titanates from oxides it was concluded that both titanates are thermodynamically stable in the high temperature region. [ABSTRACT FROM AUTHOR]

A novel galvanic-polishing-assisted near net shape forming was proposed to improve the heat dissipation capacity of the liquid-cooled plates. The coarsest upper surface roughness of channels was reduced from 74 to 37 μm. The coolant flow rate and heat dissipation capacity of the liquid-cooled plates with the polished channels were increased by 35.2 and 51.0 pct compared with those of untreated liquid-cooled plates, respectively. [ABSTRACT FROM AUTHOR]

This study emphasizes the comparative investigation of the thermal capacity of parabolic solar trough collectors with spherical-shaped balls and two types of elliptical inserts (longitudinal orientation). Hybrid nanofluid is the heat-carrying liquid obtained by mixing CuO and Al2O3 nanoparticles in distilled water. Analytical investigations are conducted for 1% vol. concentration of hybrid nanoparticles in distilled water for varying proportions. Computational analysis is chosen to obtain thermal as well as flow trends in the tube receiver. The outcomes disclosed that 13.3%, 10.02%, and 16% improvements are noted for thermal efficiency, Nusselt number, and thermal performance index with elliptical inserts of minor diameter 12 mm in the receiver, respectively, than spherical ball inserts. The highest pump work of 35 W is associated with spherical inserts at 0.033 kg/s. [ABSTRACT FROM AUTHOR]

More and more studies indicate that the effects of quantum size and energy level statistics play a crucial role in the thermodynamic properties of ultrasmall metallic grains. This paper aims to investigate how they affect the specific heat of ultrasmall metallic grains in magnetic field. As the particle size decreases, fluctuation effects and the impact of energy level separation are becoming more and more important. The method of static path approximation (SPA) is adopted to handle the fluctuation effect. Random matrix theory (RMT) is adopted due to its successful description of the energy level of metal nanoparticles. The normalized specific heat of several typical temperatures and electron spins were taken in the calculation, and the results were analyzed. It was found that spin and the spin-orbit coupling affect the specific heat very obviously, and the suppressed high spin weakens the contribution of electrons to the heat capacity. [ABSTRACT FROM AUTHOR]

Pin fin arrays, which have a high heat transfer capacity and minimal pressure loss, are currently being used as the primary cooling technique for the turbine trailing edge cooling channel used in modern gas turbines. To enhance the heat transmission efficiency of the channel, this study proposes the use of a circular-shaped pin and a teardrop pin, through both experimental and numerical investigations. The numerical simulations conducted in the Reynolds number range of 10,000 to 80,000 are used to investigate and compare the flow and heat transfer parameters of a wedge channel which has three rows of staggered circular-shaped and teardrop-shaped pin fins with a diameter of 12 mm. The experiment showed that teardrop pin fns with staggered arrangement has different effect on flow pattern and heat transfer characteristics. Heat transfer is increased by 10.45% when compared to the circular pin fins and the pressure drop of teardrop pin fins is reduced by 54.6%.Therefore thermal performance factor exhibits a 25.4% increase when compared to circular fins. [ABSTRACT FROM AUTHOR]