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A method is presented for determining the thermodynamic (equilibrium) solubility of a drug in coformer for the non-covalent derivative (NCD) systems i.e. eutectics/co-crystals. The method is based on a thermodynamic model to calculate the Gibbs energy change ∆G CC associated with forming a drug-coformer NCD system. This model includes contributions from heat capacity differences between the mixed and unmixed components, breaking up of the solid drug and coformer lattice structure, and drug ─ coformer mixing. Calculation of ∆G CC from thermal analysis data is demonstrated, and the equilibrium drug solubility in coformer is represented by minima of plots of ∆G CC versus the dissolved drug fraction (f 1 ). Eight (8) coformer molecules, namely, 1-hydroxy 2-naphthoic acid (1H-2NPH), 4-hydroxy benzoic acid (4-HBA), salicylic acid (SLC), 4-amino salicylic acid (4-ASA), 5-nitro isophthalic acid (5N-IPH), pyrazinamide (PZD), isonicotinamide (ISNCT), and picolinamide (PICO) were used for the formation of NCDs of a highly water insoluble drug febuxostat (FXT). The importance of heat capacity and interaction parameter in determining the solubility behavior of drug-coformer in the formed NCDs was discussed. Further, ∆G CC for FXT in selected NCDs were plotted as a function of composition and temperature to determine the thermodynamic stability over the range of room temperature to formulation melting. It was concluded that the thermodynamic model can reasonably predict the maximum stable drug loading in a multi-crystalline system at a particular temperature, and serve as a complementary screening tool in determining the best stoichiometric ratio of the drug and coformer in terms of solubility and thermodynamic stability., Competing Interests: Declarations Conflict of Interest There are no conflicts to declare., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

A bulk gadolinium (Gd) single crystal exhibits virtually zero remnant magnetization, a common trait among soft uniaxial ferromagnets. This characteristic is reflected in our magnetometry data showing virtually hysteresis free isothermal magnetization loops with large saturation magnetization. The absence of hysteresis allows to model the measured easy axis magnetization as a function of temperature and applied magnetic field, rather than a relation, which permits the application of Maxwell relations from equilibrium thermodynamics. Demagnetization effects broaden the isothermal first-order transition from negative to positive magnetization. By analyzing magnetization data within the coexistence regime, we deduce the isothermal entropy change and the field-induced heat capacity change. Comparing the numerically inferred heat capacity with relaxation calorimetric data confirms the applicability of the Maxwell relation. Analysis of the entropy in the mixed phase region suggests the presence of hitherto unresolved nanoscale magnetic structures in the demagnetized state of Gd. To support this prediction, Monte Carlo simulations of a 3D Ising model with dipolar interactions are performed. Analyzing the cluster size statistics and magnetization from the model provides strong qualitative support of our analytic approach., (Creative Commons Attribution license.)

Temperature dependent magnetic, electrical transport and thermal properties of polycrystalline orthorhombic CeFe 2 Al 8 intermetallic compound have been studied along with its isostructural La counterpart, LaFe 2 Al 8 . For the cerium compound, low field dc magnetization exhibits an antiferromagnetic like ordering ( T N ) ∼ 4 K. The main feature of the magnetic susceptibility plot is a broad hump spanning a large temperature range, indicating mixed valence of Ce in the compound, in good agreement with reported literature. However, contrary to the reported observations we find that the mixed valence state is very robust and was evident even up to very high magnetic fields (> 2 T). Further, in this work we report 3d core level photoemission spectra of cerium in CeFe 2 Al 8 , to understand the valence state of cerium ions in this system. Additionally, from resistivity measurements it is found that, CeFe 2 is metallic with no indication of any anomaly, till the lowest temperature of measurement. Specific heat measurements show very low value of heat capacity and electronic contribution. The isostructural La analogue, LaFe 8 is metallic with no indication of any anomaly, till the lowest temperature of measurement. Specific heat measurements show very low value of heat capacity and electronic contribution. The isostructural La analogue, LaFe 2 Al 8 compound shows broadness in susceptibility with maxima around 44 K which may be attributed to ordering of Fe moments. The comparison of Ce and La compounds brings out the role of Fe magnetic moments which may be responsible for competing with cerium moments and resulting in the dilution of long-range magnetic order, also contributing to magnetic frustration in CeFe 2 Al 8 ., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Differential Scanning Calorimetry (DSC) is a regular and powerful tool to measure the specific heat profile of various materials. Hydrogen bonds play a crucial role in stabilizing the three-dimensional structure of proteins. Naturally, information about the strength of hydrogen bonds is contained in the measured DSC profiles. Despite its obvious importance, there is no approach that would allow the extraction of such information from the heat capacity measurements. In order to connect the measured profile to microscopic properties of a polypeptide chain, a proper model is required to fit. Using recent advances in the Zimm-Bragg (ZB) theory of protein folding in water, we propose a new and efficient algorithm to process the DSC experimental data and to extract the H-bonding energy among other relevant constants. Thus, for the randomly picked set of 33 proteins, we have found a quite narrow distribution of hydrogen bonding energies from 1 to 8 kJ/mol with the average energy of intra-protein hydrogen bonds h¯=4.2±1.5 kJ/mol and the average energy of water-protein bonds as h ps ¯=3.8±1.5 kJ/mol. This is an important illustration of a tiny disbalance between the water-protein and intraprotein hydrogen bonds. Fitted values of the nucleation parameter σ belong to the range from 0.001 to 0.01, as expected. The reported method can be considered as complementary to the classical two-state approach and together with other parameters provides the protein-water and intraprotein H-bonding energies, not accessible within the two-state paradigm., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

A distance-related spectral descriptor is a graphical index with defining structure built on eigenvalues of chemical matrices relying on distances in graphs. This paper explores the predictive ability of both existing and new distance-related spectral descriptors for estimating thermodynamic characteristics of polycyclic hydrocarbons (PHs). As a standard choice, the entropy and heat capacity are selected to represent thermodynamic properties. Furthermore, 30 initial members of PHs are considered as test molecules for this study. Three new molecular matrices have been proposed and our research demonstrates that distance-spectral graphical indices built by these novel matrices surpass in efficiency relative to famous distance-spectral indices. First, a novel computational method is put forwarded to evaluate distance-spectral indices of molecular graphs. The proposed methodology is utilized to compute both pre-existing and novel distance-related spectral descriptors, with an aim to assess their predictive efficacy using experimental data pertaining to two selected thermodynamic properties. Subsequently, we identify the five most promising distance-related spectral descriptors, comprising the degree-distance and Harary energies, the recently introduced second geometric-arithmetic energy along with its associated Estrada invariant, and 2[Formula: see text] atom-bond connectivity (ABC) Estrada index. Notably, the 2[Formula: see text] ABC Estrada index and Harary energy demonstrate correlation coefficients exceeding 0.95, while certain conventional spectral indices including the distance energy as well as its associated Estrada index, display comparatively lower performance levels. Moreover, we illustrate the practical implications of our findings on specific classes of one-hexagonal nanocones and carbon polyhex nanotubes. These outcomes hold potential for enhancing the theoretical determination of certain thermodynamic attributes of these nanostructures, offering improved accuracy and minimal margin of error., (© 2024. Crown.)

This study, based on the analysis of existing experimental data, presents a third generation Calphad description of lithium, covering all temperature ranges, using nonlinear least squares in Matlab. We have expanded the SGTE database's description of lithium phases (face-centered cube, body-centered cube, liquid) down to 0 K with reasonable accuracy, taking into account the significant effort required to reconstruct the database for each element. During the evaluation process, it was determined that the low-temperature phase of lithium is fcc. The heat capacity of crystalline Li was accurately described using the extended Debye model. The third generation Calphad description of lithium utilized the two-state model and the extended Einstein model, leading to improved agreement with experimental data compared to previous assessments.

The Boson peak is a universal phenomenon in amorphous solids. It can be observed as an anomalous contribution to the low-temperature heat capacity over the Debye model. Amorphous phase-change materials (PCMs) such as Ge-Sb-Te are a family of poor glass formers with fast crystallization kinetics, being of interest for phase-change memory applications. So far, whether Boson peaks exist in PCMs is unknown and, if they do, their relevance to PCM properties is unclear. Here, we investigate the thermodynamic properties of the pseudo-binary compositions on the tie-line between Ge 15 Te 85 and Ge 15 Sb 85 from a few Kelvins to the liquidus temperatures. Our results demonstrate the evidence of the pronounced Boson peaks in heat capacity below 10 K in the amorphous phase of all compositions. By fitting the data using the Debye model combined with a modification of the Einstein model, we can extract the characteristic parameters of the Boson peaks and attribute their origin to the excess vibrational modes of dynamic defects in the amorphous solids. We find that these parameters correlate almost linearly with the Sb-content of the alloys, despite the nonmonotonic behaviors in glass forming abilities and thermal stabilities. In a broader context, we show that the correlations of the characteristic parameters of the Boson peaks with Tg and kinetic fragility, vary according to the type of bonding. Specifically, metallic glasses and conventional covalent glasses exhibit distinct patterns of dependence, whereas PCMs manifest characteristics that lie in between. A deeper understanding of the Boson peaks in PCMs holds the promise to enable predictions of material properties at higher temperatures based on features observed in low-temperature heat capacity., (Creative Commons Attribution license.)

Here a spin glass system with emergent planar ordered spin clusters is investigated. The mixed B-site pyrochlore Gd 2 ScNbO 7 has been synthesized and characterized through a variety of techniques, including x-ray diffraction, magnetic susceptibility, muon spin relaxation, heat capacity and neutron scattering. Despite a Curie-Weiss temperature of -3.93(3) K, indicating net antiferromagnetic interactions, no signs of long ranged magnetic ordering are found down to T = 0.3 K. Instead, a disordered magnetic state emerges with a small correlation length of 2.1(1) Å of single tetrahedra. A Reverse Monte Carlo analysis of the polarized neutron scattering data reveals short-range antiferromagnetic order with emergent XY spin ordering similar to the parent pyrochlore compounds. Muon spin relaxation, and AC susceptibility measurements confirm that the magnetization condenses into a glass, with 10 % of the potential entropy missing in the specific heat. This magnetic ground state is similar to what is observed in Gd 2 Sn 2 O 7 just above the ordering temperature, without the eventual long-range ordering at low temperature., (Creative Commons Attribution license.)

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C 4 (MIm) 2 ][NTf 2 ] 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 [C 4 (MIm) 2 ][NTf 2 ] 2 , the temperature of fusion T ° fus = (337.88 ± 0.01) K has been determined by the fractional melting experiments, the enthalpy of fusion Δ fus H ° = (52.79 ± 0.28) kJ mol -1 has been measured using the calorimetric method of continuous energy input, and the entropy of fusion Δ fus S has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity -1 mol -1 has also been evaluated. The standard thermodynamic functions of the studied dicationic ionic compound, namely, the heat capacity C p °( 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.

Hybrid layered double perovskites (HLDPs), representing the two-dimensional manifestation of halide double perovskites, have elicited considerable interest owing to their intricate chemical bonding hierarchy and structural diversity. This intensified interest stems from the diverse options available for selecting alternating octahedral coordinated trivalent [M(III)] and monovalent metal centers [M(I)], along with the distinctive nature of the cationic organic amine located between the layers. Here, we have synthesized three new compounds with general formula (R'/R'') 4/2 M(III)M(I)Cl 8 ; where R'=C 3 H 7 NH 3 (i.e. 3N) and R''=NH 3 C 4 H 8 NH 3 (i.e. 4N4); M(III)=In 3+ or Ru 3+ ; M(I)=Cu + by simple solution-based acid precipitation method. The structural analysis reveals that (4N4) 2 CuInCl 8 and (4N4) 2 CuRuCl 8 adopt the layered Dion Jacobson (DJ) structure, whereas (3N) 4 CuInCl 8 exhibits layered Ruddlesden Popper (RP) structure. The alternative octahedra within the inorganic layer display distortions and tilting. Three compounds show temperature-dependent structural phase transitions where changes in the staking of inorganic layer, extent of octahedral tilting and reorientation of organic spacers with temperature have been noticed. We have achieved ultralow lattice thermal conductivity (κ L ) in the HLDPs in the 2 to 300 K range, marking a distinctive feature within the realm of HLDP systems. The RP-HLDP compound, (3N) 4 CuInCl 8 , demonstrates anisotropy in κ L while measured parallel and perpendicular to layer stacking, showcasing ultralow κ L of 0.15 Wm -1 K -1 at room temperature, which is one of the lowest values obtained among Pb-free metal halide perovskite. The observed ultralow κ L in three new HLDPs is attributed to significant lattice anharmonicity arising from the chemical bonding heterogeneity and soft crystal structure, which resulted in low-energy localized optical phonon modes that suppress heat-carrying acoustic phonons., (© 2024 Wiley-VCH GmbH.)

The thermodynamic characteristics of a pair-interacting hole gas localized in a Ge/Si lens-shaped quantum dot are studied. The pair-interaction potential is modeled by the oscillator function, which depends on the distance between the particles. The analytical form of the spectra makes it possible to calculate the partition function in Boltzmann approximation. Based on the partition function mean and free energies, heat capacity and entropy of the interacting gas are calculated. Interaction between particles substantially changes the behavior of the thermodynamic properties in comparison with the non-interacting gas case. In particular, the gas undergoes a first-order phase transition driven by the height of the upper (or lower) section of QD, resulting in a changing symmetry of the lens-shaped QD., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hayk Sarkisyan reports financial support was provided by Russian-Armenian Slavonic University. Hayk Sarkisyan reports a relationship with Russian-Armenian Slavonic University that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Author(s).)

The thermodynamics of secondary p53 binding sites on MDM2 and MDMX were evaluated using p53 peptides containing residues 16-29, 17-35, and 1-73. All the peptides had large, negative heat capacity (ΔC p ), consistent with the burial of p53 residues F19, W23, and L26 in the primary binding sites of MDM2 and MDMX. MDMX has a higher affinity and more negative ΔC p than MDM2 for p53 17-35 , which is due to MDMX stabilization and not additional interactions with the secondary binding site. ΔC p measurements show binding to the secondary site is inhibited by the disordered tails of MDM2 for WT p53 but not a more helical mutant where proline 27 is changed to alanine. This result is supported by all-atom molecular dynamics simulations showing that p53 residues 30-35 turn away from the disordered tails of MDM2 in P27A 17-35 and make direct contact with this region in p53 17-35 . Molecular dynamics simulations also suggest that an intramolecular methionine-aromatic motif found in both MDM2 and MDMX structurally adapts to support multiple p53 binding modes with the secondary site. ΔC p measurements also show that tighter binding of the P27A mutant to MDM2 and MDMX is due to increased helicity, which reduces the energetic penalty associated with coupled folding and binding. Our results will facilitate the design of selective p53 inhibitors for MDM2 and MDMX., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Protein stability is a critical aspect of molecular biology and biochemistry, hinges on an intricate balance of thermodynamic and structural factors. Determining protein stability is crucial for understanding and manipulating biological machineries, as it directly correlated with the protein function. Thus, this study delves into the intricacies of protein stability, highlighting its dependence on various factors, including thermodynamics, thermal conditions, and structural properties. Moreover, a notable focus is placed on the free energy change of unfolding (ΔG unfolding ), change in heat capacity (ΔCp) with protein structural transition, melting temperature (Tm) and number of disulfide bonds, which are critical parameters in understanding protein stability. In this study, a machine learning (ML) predictive model was developed to estimate these four parameters using the primary sequence of the protein. The shortfall of available tools for protein stability prediction based on multiple parameters propelled the completion of this study. Convolutional Neural Network (CNN) with multiple layers was adopted to develop a more reliable ML model. Individual predictive models were prepared for each property, and all the prepared models showed results with high accuracy. The R 2 (coefficient of determination) of these models were 0.79, 0.78, 0.92 and 0.92, respectively, for ΔG, ΔCp, Tm and disulfide bonds. A case study on stability analysis of two homologous proteins was presented to validate the results predicted through the developed model. The case study included in silico analysis of protein stability using molecular docking and molecular dynamic simulations. This validation study assured the accuracy of each model in predicting the stability associated properties. The alignment of physics-based principles with ML models has provided an opportunity to develop a fast machine learning solution to replace the computationally demanding physics-based calculations used to determine protein stability. Furthermore, this work provided valuable insights into the impact of mutation on protein stability, which has implications for the field of protein engineering. The source codes are available at https://github.com/Growdeatechnology., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest regarding the publication of this manuscript., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study employs ab initio calculations based on density functional theory (DFT) to investigate the structural properties, 1 H-NMR spectra, and vibrational spectra of methane sulfonic acid (MSA) at low degree of hydration. The findings reveal that energetically stable structures are formed by small clusters consisting of one or two MSA molecules (m = 1 and 2) and one or two water molecules in (MSA) m ·(H 2 O) n (m = 1-2 and n = 1-5).These stable structures arise from the formation of strong cyclic hydrogen bonds between the proton of the hydroxyl (OH) group in MSA and the water molecules. However, clusters containing three or more water molecules (n > 2) exhibit proton transfer from MSA to water, resulting in the formation of ion-pairs composed of CH 3 SO 3 - and H 3 O + species. The measured 1 H-NMR spectra demonstrate the presence of hydrogen-bonded interactions between MSA and water, with a single MSA molecule interacting with water molecules. This interaction model accurately represents the hydrogen bonding network, as supported by the agreement between the experimental and calculated NMR chemical shift results., (© 2024. The Author(s).)

1,3,5-Tris-(α-naphthyl)benzene is an organic non-electrolyte with notable stability of an amorphous phase. Its glassy and supercooled liquid states were previously studied by spectroscopic and calorimetric methods. Despite the continuing interest in its amorphous state and, particularly, vapor-deposited glasses, the thermodynamic parameters of the vaporization of 1,3,5-tris-(α-naphthyl)benzene have not been obtained yet. Likewise, the reliable evaluation of the thermodynamic parameters of fusion below the melting point, required to establish the thermodynamic state of its glass, is still an unsolved problem. In this work, the heat capacities of crystalline and liquid phases, the temperature dependence of the saturated vapor pressures, fusion and vaporization enthalpies were determined using differential and fast scanning calorimetry and were verified using the estimates based on solution calorimetry. The structural features of 1,3,5-tris-(α-naphthyl)benzene are discussed based on the computations performed and the data on the molecular refractivity. The consistency between the values obtained by independent techniques was demonstrated.

In the selection and design of ionic liquids (ILs) for various applications, including heat transfer fluids, thermal energy storage materials, fuel cells, and solvents for chemical processes, heat capacity is a key thermodynamic property. While several attempts have been made to develop predictive models for the estimation of the heat capacity of ILs in their liquid phase, none so far have been reported for the ILs' solid crystal phase. This is particularly important for applications where ILs will be used for thermal energy storage in the solid phase. For the first time, a model has been developed and used for the prediction of crystal phase heat capacity based on extending and modifying a previously developed hybrid group contribution model (GCM) for liquid phase heat capacity. A comprehensive database of over 5000 data points with 71 unique crystal phase ILs, comprising 42 different cations and 23 different anions, was used for parameterization and testing. This hybrid model takes into account the effect of the anion core, cation core, and subgroups within cations and anions, in addition to the derived indirect parameters that reflect the effects of branching and distribution around the core of the IL. According to the results, the developed GCM can reliably predict the crystal phase heat capacity with a mean absolute percentage error of 6.78%. This study aims to fill this current gap in the literature and to enable the design of ILs for thermal energy storage and other solid phase applications.

An extensive thermodynamic study of N -methylformamide (CAS RN: 123-39-7) and N , N -dimethylformamide (CAS RN: 68-12-2), is presented in this work. The liquid heat capacities of N -methylformamide were measured by Tian-Calvet calorimetry in the temperature interval (250-300) K. The vapor pressures for N -methylformamide and N , N -dimethylformamide were measured using static method in the temperature range 238 K to 308 K. The ideal-gas thermodynamic properties were calculated using a combination of the density functional theory (DFT) and statistical thermodynamics. A consistent thermodynamic description was developed using the method of simultaneous correlation, where the experimental and selected literature data for vapor pressures, vaporization enthalpies, and liquid phase heat capacities and the calculated ideal-gas heat capacities were treated together to ensure overall thermodynamic consistency of the results. The resulting vapor pressure equation is valid from the triple point to the normal boiling point temperature.

This study reports the synthesis of type-I Ba 8 CuNi 2.5 Ga 10 Si 33.5 clathrate as a single crystal by the flux method and physical properties investigations such as structural, chemical, magnetic, and thermal properties. Structural refinements indicate Ba atoms are situated at 2a and 6d positions with mixed occupancy across framework sites. Raman spectroscopy assessed host-guest interactions, while the compound's morphology and composition were investigated by the scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses. Magnetic properties revealed ferromagnetic interactions characterized by a positive Weiss constant and weak ferromagnetic hysteresis. The compound's metallic nature is evidenced by increased resistivity with temperature. The Sommerfeld coefficient, estimated at 12.59 mJ mol -1  K -2 from heat capacity data, alongside a pronounced peak around 15 K in the C p /T 3 vs T plot, suggests an Einstein contribution in heat capacity., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

In this investigation, we set out first to characterize the thermodynamics of Mg(AlH 4 ) 2 and secondly to use the determined data to reevaluate and update existing estimation procedures for heat capacity functions, enthalpies of formation and absolute entropies of alanates. Within this study, we report the heat capacity function of Mg(AlH 4 ) 2 in the temperature range from 2 K to 370 K and its enthalpy of formation and absolute entropy at 298.15 K, being - 70 . 6 ± 3 . 6 ${ - 70.6 \pm 3.6}$  kJ mol -1 and 133.06 J (K mol) -1 , respectively. Using these values, we updated and expanded methods for the estimation of thermodynamic data of alanates., (© 2023 The Authors. ChemPhysChem published by Wiley-VCH GmbH.)

The chalcogenides of p-block elements constitute a significant category of materials with substantial potential for advancing the field of electronic and optoelectronic devices. This is attributed to their exceptional characteristics, including elevated carrier mobility and the ability to fine-tune band gaps through solid solution formation. These compounds exhibit diverse structures, encompassing both three-dimensional and two-dimensional configurations, the latter exemplified by the compound In 2 Se 3 . Sesqui-chalcogenides were synthesized through the direct reaction of highly pure elements within a quartz ampoule. Their single-phase composition was confirmed using X-ray diffraction, and the morphology and chemical composition were characterized using scanning electron microscopy. The compositions of all six materials were also confirmed using X-ray photoelectron spectroscopy and Raman spectroscopy. This investigation delves into the thermodynamic properties of indium and gallium sesqui-chalcogenides. It involves low-temperature heat capacity measurements to evaluate standard entropies and Tian-Calvet calorimetry to elucidate the temperature dependence of heat capacity beyond the reference temperature of 298.15 K, as well as the enthalpy of formation assessed from DFT calculations.

Coupled hindered rotor model is crucial for exploring the rotational dynamics of complex molecules under different external environments. When coupled hindered rotor molecules are subjected to the combined action of static electric and laser fields, their rotational dynamics get significantly modified, leading to interesting physics. In this study, we solve the time-independent Schrödinger equation for the coupled pair of rotors in the combined action of static electric and laser fields using the nine-point finite difference method and obtain rotational energy spectra and eigenvectors. We then use the partition function approach to understand thermal behaviour by studying thermal properties like heat capacity and entropy. We also explore the impact of temperature, coupling strength, and external fields strength parameters on these properties. The orientation of the coupled rotor is strongly dependent on the coupling strength between the coupled rotors as well as the hindrance. We analyse this directional parameter under a broad range of barrier height, coupling strength, and external fields strength parameters. Our analysis may provide insight into the rich and interesting physics, which may pave the way for future experimental and theoretical studies in this area., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Estimating the total thermal capacity for phase change material (PCM) as heat storage material is extremely important to set the proper operational parameter of the latent storage tank (LST) unit. However, estimating the total thermal capacity for solid-liquid PCM is relatively complex due to temperature-dependent properties for each phase. Thus, predicting the state of charge (SoC) indicator for the LST unit is technically complex. The common approach is taken by estimating the heat of fusion during the melting process and monitoring the working fluid temperature, which makes the SoC estimation less accurate. The present project proposes a reliable method with an affordable apparatus to estimate the total thermal capacity simultaneously based on the temperature of low-temperature PCM. Moreover, sensible heating during phase transition is also estimated precisely based on the energy balance at a given temperature. The developed apparatus employs widely available components at an affordable cost which is possible for further customization. Validation and characterization are done comprehensibly by comparing the measurement from differential scanning calorimetry and previous studies. The results indicate a suitable estimation for estimating the solid-liquid heat capacity, including partial heat capacity and latent heat of fusion., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Author(s).)

In the present study, single crystals and polycrystalline material of K 4 CaSi 6 O 15 were prepared from solid-state reactions between stoichiometric mixtures of the corresponding oxides/carbonates. Heat capacity ( C p ) measurements above room temperature using a differential scanning calorimeter indicated that two thermal effects occurred at approximately T 1  = 462 K and T 2  = 667 K, indicating the presence of structural phase transitions. The standard third-law entropy of K 4 CaSi 6 O 15 was determined from low-temperature C p 's measured by relaxation calorimetry using a Physical Properties Measurement System and amounts to S °(298K) = 524.3 ± 3.7 J·mol -1 ·K -1 . For the 1 st transition, the enthalpy change Δ H tr1  = 1.48 kJ·mol and the entropy change Δ S tr1  = 3.25 J·mol -1 ·K -1 , whereas Δ H tr2  = 3.33 kJ·mol -1 and Δ S tr2  = 5.23 J·mol -1 ·K -1 were determined for the 2 nd transition. The compound was further characterized by in-situ single-crystal X-ray diffraction between ambient temperature and 1063 K. At 773 K, the high-temperature phase stable above T 2 has the following basic crystallographic data: monoclinic symmetry, space group P 2 1 / c , a  = 6.9469(4) Å, b  = 9.2340(5) Å, c  = 12.2954(6) Å, β = 93.639(3)°, V  = 787.13(7) Å 3 , Z  = 2. It belongs to the group of interrupted framework silicates and is based on tertiary (Q 3 -type) [SiO 4 ]-tetrahedra. Together with the octahedrally coordinated Ca-cations, a three-dimensional mixed polyhedral network structure is formed, in which the remaining K-ions provide charge balance by occupying voids within the net. The intermediate temperature modification stable between T 1 and T 2 shows a (3+2)-dimensional incommensurately modulated structure that is characterized by the following q-vectors: q 1  = (0.057, 0.172, 0.379), q 2  = (-0.057, 0.172, -0.379). The crystal structures of the high- and the previously studied ambient temperature polymorph (space group Pc ) are topologically equivalent and show a group-subgroup relationship. The index of the low- in the high-symmetry group is six and involves both, losses in translation as well as point group symmetry. The distortion is based on shifts of the different atom species and tilts of the 4- and 6-fold coordination polyhedra. Actually, for some of the oxygen atoms, the displacements exceed 0.5 Å. A more detailed analysis of the distortions relating to both structures has been performed using mode analysis, which revealed that the primary distortion mode transforms according to the Λ 1 irreducible representation of P 2 1 / c . However, other modes with smaller distortion amplitudes are also involved., (© 2023 The Authors. Journal of the American Ceramic Society published by Wiley Periodicals LLC on behalf of American Ceramic Society.)

In this work, we present a comprehensive study of the thermodynamic properties of 3-and 4-ethoxyacetanilides. The heat capacities in crystalline, liquid, and supercooled liquid states from 80 to 475 K were obtained using adiabatic, differential scanning (DSC), and fast scanning (FSC) calorimetries. The fusion enthalpies at T m were combined from DSC measurement results and the literature data. The fusion enthalpies at 298.15 K were evaluated in two independent ways: adjusted according to Kirchhoff's law of thermochemistry, and using Hess' law. For the latter approach, the enthalpies of the solution in DMF in crystalline and supercooled liquid states were derived. The values obtained by the two methods are consistent with each other. The standard thermodynamic functions (entropy, enthalpy, and Gibbs energy) between 80 and 470 K were calculated.

The CLC-ec1 chloride/proton antiporter is a membrane-embedded homodimer with subunits that can dissociate and associate, but the thermodynamic driving forces favor the assembled dimer at biological densities. Yet, the physical reasons for this stability are confounding as dimerization occurs via the burial of hydrophobic interfaces away from the lipid solvent. For binding of nonpolar surfaces in aqueous solution, the driving force is often attributed to the hydrophobic effect, but this should not apply in the membrane since there is very little water. To investigate this further, we quantified the thermodynamic changes associated with CLC dimerization in membranes by carrying out a van 't Hoff analysis of the temperature dependency of the free energy of dimerization, Δ G° . To ensure that the reaction reached equilibrium at different temperatures, we utilized a Förster resonance energy transfer assay to report on relaxation kinetics of subunit exchange as a function of temperature. Equilibration times were then applied to measure CLC-ec1 dimerization isotherms at different temperatures using the single-molecule subunit-capture photobleaching analysis approach. The results demonstrate that the dimerization free energy of CLC in Escherichia coli -like membranes exhibits a nonlinear temperature dependency corresponding to a large, negative change in heat capacity, a signature of solvent ordering effects such as the hydrophobic effect. Consolidating this with our previous molecular analyses suggests that the nonbilayer defect required to solvate the monomeric state is one source of the observed change in heat capacity and indicates the existence of a generalizable driving force for protein association in membranes.

Three mononuclear compounds formulated as {M[(2-1H-tetrazol-5-yl)pyridine] 2 (H 2 O) 2 } (M = Fe II ( 1 ), Co II ( 2 ), Cu II ( 3 )) were reported and synthesized. Their space group is monoclinic, P 2 1 /c, revealed by single-crystal X-ray diffraction. Antiferromagnetic interactions exist in Compounds 1 , 2 and 3 , as evidenced by magnetic and low-temperature heat capacity measurements. In addition, their thermodynamic functions were determined by a relaxation calorimeter, indicating that Compound 1 exhibits a Schottky anomaly in low-temperature heat capacity. This work can provide an important fundamental basis for the research of the thermophysical properties of molecular-based magnetic materials.

This paper studies the dependence of the specific heat capacity (C p ) of activated carbon obtained by the activation of coke fines on temperature (T, K) and the dependence of electrical resistance ( R , Om) on temperature (T, K). In the course of the work, it was found that in the temperature range of 298.15-448 K on the curve of dependence C p - f (T) at 323 K there is a jump in heat capacity, associated with a phase transition of the second kind. Measurements of the temperature dependence of electrical resistance on temperature were also carried out, which showed that activated carbon in the temperature range of 293-343 K exhibits metallic conductivity, turning into a semiconductor in the temperature range of 343-463 K. The calculation of the band gap showed that the resulting activated carbon is a semiconductor with a moderately narrow band gap. The satisfactory agreement of the phase transition temperatures on the curves of the temperature dependences of the heat capacity on temperature (323 K) and on the curves of the dependences of electrical resistance and the relative permittivity on temperature (343 K) indicates the nature of this phase transition, i.e., at a temperature of 323 K, the change in heat capacity is associated with the transition from semiconductor conductivity to metallic.

The characterization of protein stability is essential for understanding the functions of proteins. Hydroxysteroid dehydrogenase is involved in the biosynthesis of steroid hormones and the detoxification of xenobiotic carbonyl compounds. However, the stability of hydroxysteroid dehydrogenases has not yet been characterized in detail. Here, we determined the changes in Gibbs free energy, enthalpy, entropy, and heat capacity of unfolding for 3α-hydroxysteroid dehydrogenase/carbonyl reductase (3α-HSD/CR) by varying the pH and urea concentration through differential scanning fluorimetry and presented pH-dependent protein stability as a function of temperature. 3α-HSD/CR shows the maximum stability of 30.79 kJ mol -1 at 26.4°C, pH 7.6 and decreases to 7.74 kJ mol -1 at 25.7°C, pH 4.5. The change of heat capacity of 30.25 ± 1.38 kJ mol -1  K -1 is obtained from the enthalpy of denaturation as a function of melting temperature at varied pH. Two proton uptakes are linked to protein unfolding from residues with differential pK a of 4.0 and 6.5 in the native and denatured states, respectively. The large positive heat capacity change indicated that hydrophobic interactions played an important role in the folding of 3α-HSD/CR. These studies reveal the mechanism of protein unfolding in HSD and provide a convenient method to extract thermodynamic parameters for characterizing protein stability using differential scanning fluorimetry., (© 2023 The Protein Society.)

As a follow-up to our effort to establish reliable thermodynamic data for amino acids, the heat capacity and phase behavior are reported for N -acetyl glycine amide (CAS RN: 2620-63-5), N -acetyl-L-alanine amide (CAS RN: 15962-47-7), N -acetyl-L-valine amide (CAS RN: 37933-88-3), N -acetyl-L-isoleucine amide (CAS RN: 56711-06-9), and N -acetyl-L-leucine amide (CAS RN: 28529-34-2). Prior to heat capacity measurement, thermogravimetric analysis and X-ray powder diffraction were performed to determine decomposition temperatures and initial crystal structures, respectively. The crystal heat capacities of the five N -acetyl amino acid amides were measured by Tian-Calvet calorimetry in the temperature interval (266-350 K), by power compensation DSC in the temperature interval (216-471 K), and by relaxation (heat-pulse) calorimetry in the temperature interval (2-268 K). As a result, reference heat capacities and thermodynamic functions for the crystalline phase from 0 K up to 470 K were developed.

Titanium-manganites of LaLi 2 TiMnO 6 and LaNa 2 TiMnO 6 were synthesized by the methods of ceramic technology from the oxides of lanthanum, titanium (IV), manganese (III), and the carbonates of lithium and sodium. The types of their syngony and the parameters of their gratings were determined radiographically. The isobaric heat capacities of titanium-manganites were measured with experimental calorimetry in the range of 298.15-673 K. It was found that on the dependence curve of heat capacity versus temperature of C° p ~f(T), for LaLi 2 TiMnO 6 at 348 K and 598 K, and LaNa 2 TiMnO 6 at 348 K, there are abnormal jumps in heat capacity, probably related to phase transitions of the second kind. Taking into account the temperatures of the phase transitions, the equations of the temperature dependence of the heat capacity of titanium-manganites were derived. Their standard entropies were calculated by the ion increments method. Temperature dependences of the thermodynamic functions of S°(T), H°(T)-H°(298.15), and Φ xx (T) were calculated using the experimental data on heat capacities and the calculated values of the standard entropies. The standard heat capacities of the studied compounds were calculated by the independent methods of ion increments and Debye, the values of which were in satisfactory agreement with the experimental data. The standard enthalpy of the formation of LaLi 2 TiMnO 6 and LaNa 2 TiMnO 6 was calculated according to the methodology developed by the authors. The conducted electrophysical studies determined the nature of the second-order phase transition and the semiconductor features of their conductivity. Thus, all the above-mentioned data on the experimental and calculated studies of the temperature dependence of heat capacity, the thermodynamic functions to determine a standard enthalpy of formation of LaLi 2 TiMnO 6 and LaNa 2 TiMnO 6 , and the investigation of their electrical properties are absolutely new, and they have no analogues.

Amyloid formation is a hallmark of various neurodegenerative disorders. In this contribution, energy landscapes are explored for various hexapeptides that are known to form amyloids. Heat capacity (CV) analysis at low temperature for these hexapeptides reveals that the low energy structures contributing to the first heat capacity feature above a threshold temperature exhibit a variety of backbone conformations for amyloid-forming monomers. The corresponding control sequences do not exhibit such structural polymorphism, as diagnosed via end-to-end distance and a dihedral angle defined for the monomer. A similar heat capacity analysis for dimer conformations obtained using basin-hopping global optimisation shows clear features in end-to-end distance versus dihedral correlation plots, where amyloid-forming sequences exhibit a preference for larger end-to-end distances and larger positive dihedrals. These results hold true for sequences taken from tau, amylin, insulin A chain, a de novo designed peptide, and various control sequences. While there is a little overall correlation between the aggregation propensity and the temperature at which the low-temperature CV feature occurs, further analysis suggests that the amyloid-forming sequences exhibit the key CV feature at a lower temperature compared to control sequences derived from the same protein.

Temperature influences dynamics and state-equilibrium distributions in all molecular processes, and only a relatively narrow range of temperatures is compatible with life-organisms must avoid temperature extremes that can cause physical damage or metabolic disruption. Animals evolved a set of sensory ion channels, many of them in the family of transient receptor potential cation channels that detect biologically relevant changes in temperature with remarkable sensitivity. Depending on the specific ion channel, heating or cooling elicits conformational changes in the channel to enable the flow of cations into sensory neurons, giving rise to electrical signaling and sensory perception. The molecular mechanisms responsible for the heightened temperature-sensitivity in these ion channels, as well as the molecular adaptations that make each channel specifically heat- or cold-activated, are largely unknown. It has been hypothesized that a heat capacity difference (ΔC p ) between two conformational states of these biological thermosensors can drive their temperature-sensitivity, but no experimental measurements of ΔC p have been achieved for these channel proteins. Contrary to the general assumption that the ΔC p is constant, measurements from soluble proteins indicate that the ΔC p is likely to be a function of temperature. By investigating the theoretical consequences for a linearly temperature-dependent ΔC p on the open-closed equilibrium of an ion channel, we uncover a range of possible channel behaviors that are consistent with experimental measurements of channel activity and that extend beyond what had been generally assumed to be possible for a simple two-state model, challenging long-held assumptions about ion channel gating models at equilibrium.

In this paper, the Kubo-Greenwood formula based on the tight-binding model is used to investigate the effects of the bias voltage and magnetic field on the electrical conductivity and heat capacity of the trilayer BP and BN with energy-stable stacking structures. The results show that electronic and thermal properties of the selected structures can be significantly modified by external fields. The position and intensity of DOS peaks and the band gap of selected structures are affected by the external fields. When external fields increases above critical value, the band gap decreases to zero and semiconductor-metallic transition occurs. The results show that the thermal properties of the BP and BN structures are zero in TZ temperature region and increase by temperature above TZ. The increasing rate for thermal properties depends on the stacking configuration and changes with the bias voltage and magnetic field. In the presence of the stronger field, the TZ region decreases below 100 K. Compared to the BP structures, the BN types with larger band gap has smaller electrical conductivity which can be increased in order to 3L-BP by applying the stronger magnetic field or bias voltage. These results are interesting for the future development of nanoelectronic devices., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The temperature dependence of the partial heat capacity of the native protein structure in an aqueous solution has been analyzed. It is shown that the strictly linear temperature dependence is due to the contributions of the vibrational and conformational components, which indicates volume consistensy and the absence of conformational transitions up to the main two-state transition. The two-level structural and functional organization of the protein three-dimensional structure are considered in relation to the energy and conformational entropy properties in accordance with the principles of the organization of the protein macromolecule.Communicated by Ramaswamy H. Sarma.

The characterization of cytisine (CYT) and its blends with poly(lactic acid) was performed using thermal analysis, elemental analysis, infrared spectroscopy, and powder X-ray diffractometry. The heat capacities, total enthalpy, and phase transitions of CYT were established from 1.8 to 448.15 K (-271.35 - 175 °C) by advanced thermal analysis. Data were obtained using a Quantum Design Physical Property Measurement System (PPMS) and a differential scanning calorimetry (DSC). The low-temperature heat capacity of the crystalline CYT in the range of 1.8 to 300 K (-271.35 - 26.86 °C) was measured by PPMS and fitted to a theoretical model in the low temperature region below 11 K (-262.15 °C), to orthogonal polynomials in the middle range 5 K < T < 60 K (-268.15 °C < t < -213.15 °C) and to the Debye and Einstein functions in the high range of temperature above 60 K (-213.15 °C). The liquid heat capacity was calculated based on the approximated linear regression data above the molten state of the experimental heat capacity of CYT obtained by the standard DSC measurements, and it was expressed as C p liquid = 0.0838T + 346.78 J·K -1 . The calculated heat capacity in the solid state was extended to a higher temperature and was used, together with liquid heat capacity, as the reference baselines for the advanced thermal analysis of CYT. The PPMS and DSC/TMDSC methods are complementary methods for thermal analysis of cytisine. The PPMS method allowed determination of the equilibrium heat capacity in the solid state, which together with the equilibrium heat capacity in the liquid state allowed to analyze of the experimental apparent heat capacity of cytisine obtained based on DSC. The melting temperature and the total heat of fusion of crystalline material were established as 431.8 K (158.65 °C) and 26.5 kJ·mol -1 . The calculated heat capacity in the solid state was extended to a higher temperature and was used, together with liquid heat capacity, as the reference baselines for the advanced thermal analysis of CYT. The PPMS and DSC/TMDSC methods are complementary methods for thermal analysis of cytisine. The PPMS method allowed determination of the equilibrium heat capacity in the solid state, which together with the equilibrium heat capacity in the liquid state allowed to analyze of the experimental apparent heat capacity of cytisine obtained based on DSC. The melting temperature and the total heat of fusion of crystalline material were established as 431.8 K (158.65 °C) and 26.5 kJ·mol -1 , respectively. The solid and liquid heat capacities and transition parameters of CYT were applied to calculate total enthalpies for fully amorphous and crystalline states. Analyses of DSC and X-ray confirmed the presence of the solid-solid transition linking with not so far described a polymorphism phenomenon of CYT. Based on the thermogravimetric analysis the temperature of degradation of CYT was determined as 460.5 K (187.35 °C). Also, a preliminary thermal analysis of the blends of cytisine and poly(lactic acid) as a new candidate for drug delivery system was presented., (Copyright © 2023 University of Rzeszow. Published by Elsevier B.V. All rights reserved.)

Thermodynamics of liquid water in terms of a non-standard approach-the ion-molecular model-is considered. Water is represented as a dense gas of neutral H 2 O molecules and single charged H 3 O + and OH - ions. The molecules and ions perform thermal collisional motion and interconvert due to ion exchange. The energy-rich process-vibrations of an ion in a hydration shell of molecular dipoles-well known to spectroscopists with its dielectric response at 180 cm -1 (5 THz), is suggested to be key for water dynamics. Taking into account this ion-molecular oscillator, we compose an equation of state of liquid water to obtain analytical expressions for the isochores and heat capacity.

LaNb 0.8 M 0.2 O 4-δ (where M=As, Sb, V, and Ta) oxides with pentavalent elements of different ionic sizes were synthesized by a solid-state reaction method. The vibrational properties of these oxides have been investigated. These studies revealed that the substituent element influences both Debye temperature value as well as the Raman active vibrational modes. Additionally, the low-temperature vibrational properties of LaNb 0.8 Sb 0.2 O 4-δ have been determined to show the phase transition occurrence at 260 K which is lower than previously reported., (© 2022 Wiley-VCH GmbH.)

In an effort to establish reliable thermodynamic data for amino acids, heat capacity and phase behavior are reported for L-cysteine (CAS RN: 52-90-4), L-serine (CAS RN: 56-45-1), L-threonine (CAS RN: 72-19-5), L-lysine (CAS RN: 56-87-1), and L-methionine (CAS RN: 63-68-3). Prior to heat capacity measurements, initial crystal structures were identified by X-ray powder diffraction, followed by a thorough investigation of the polymorphic behavior using differential scanning calorimetry in the temperature range from 183 K to the decomposition temperature determined by thermogravimetric analysis. Crystal heat capacities of all five amino acids were measured by Tian-Calvet calorimetry in the temperature interval (262-358) K and by power compensation DSC in the temperature interval from 215 K to over 420 K. Experimental values of this work were compared and combined with the literature data obtained with adiabatic calorimetry. Low-temperature heat capacities of L-threonine and L-lysine, for which no or limited literature data was available, were measured using the relaxation (heat pulse) calorimetry. As a result, reference heat capacities and thermodynamic functions for the crystalline phase from near 0 K to over 420 K were developed.

The thermal properties, including the heat capacity, thermal conductivity, effusivity, diffusivity, and phonon density of states of silicon-based nanomaterials are analyzed using a molecular dynamics calculation. These quantities are calculated in more detail for bulk silicon, porous silicon, and a silicon aerocrystal (aerogel), including the passivation of the porous internal surfaces with hydrogen, hydroxide, and oxygen ions. It is found that the heat capacity of these materials increases monotonically by up to 30% with an increase in the area of the porous inner surface and upon its passivation with these ions. This phenomenon is explained by a shift of the phonon density of states of the materials under study to the low-frequency region. In addition, it is shown that the thermal conductivity of the investigated materials depends on the degree of their porosity and can be changed significantly upon the passivation of their inner surface with different ions. It is demonstrated that, in the various simulated types of porous silicon, the thermal conductivity changes by 1-2 orders of magnitude compared with the value for bulk silicon. At the same time, it is found that the nature of the passivation of the internal nanosilicon surfaces affects the thermal conductivity. For example, the passivation of the surfaces with hydrogen does not significantly change this parameter, whereas a passivation with oxygen ions reduces it by a factor of two on average, and passivation with hydroxyl ions increases the thermal conductivity by a factor of 2-3. Similar trends are observed for the thermal effusivities and diffusivities of all the types of nanoporous silicon under passivation, but, in that case, the changes are weaker (by a factor of 1.5-2). The ways of tuning the thermal properties of the new nanostructured materials are outlined, which is important for their application.

The ZrSiS-type materials have gained intensive attentions. The magnetic version of the ZrSiS-type materials, Ln SbTe ( Ln = Lanthanide), offers great opportunities to explore new quantum states owing to the interplay between magnetism and electronic band topology. Here, we report the growth and characterization of the non-magnetic LaSbSe of this material family. We found the metallic transport, low magnetoresistance and non-compensated charge carriers with relatively low carrier density in LaSbSe. The specific heat measurement has revealed distinct Sommerfeld coefficient and Debye temperature in comparison to LaSbTe. Such addition of a new Ln SbSe selenide compound could provide the alternative material choices in addition to Ln SbTe telluride materials., Competing Interests: Conflicts of Interest: The authors declare no conflict of interest.

This study correlated biomass heat capacity (Cp) with the chemistry (sulfur and ash content), crystallinity index, and temperature of various samples. A five-parameter linear correlation predicted 576 biomass Cp samples from four different origins with the absolute average relative deviation (AARD%) of ~1.1%. The proportional reduction in error (REE) approved that ash and sulfur contents only enlarge the correlation and have little effect on the accuracy. Furthermore, the REE showed that the temperature effect on biomass heat capacity was stronger than on the crystallinity index. Consequently, a new three-parameter correlation utilizing crystallinity index and temperature was developed. This model was more straightforward than the five-parameter correlation and provided better predictions (AARD = 0.98%). The proposed three-parameter correlation predicted the heat capacity of four different biomass classes with residual errors between -0.02 to 0.02 J/g∙K. The literature related biomass Cp to temperature using quadratic and linear correlations, and ignored the effect of the chemistry of the samples. These quadratic and linear correlations predicted the biomass Cp of the available database with an AARD of 39.19% and 1.29%, respectively. Our proposed model was the first work incorporating sample chemistry in biomass Cp estimation.

Thermal energy storage offers numerous benefits by reducing energy consumption and promoting the use of renewable energy sources. Thermal energy storage materials have been investigated for many decades with the aim of improving the overall efficiency of energy systems. However, finding solid materials that meet the requirement of high heat capacity has been a grand challenge for material scientists. Herewith, by training various machine learning models on 3377 high-quality data from full density functional theory (DFT) calculations, we efficiently search for potential materials with high heat capacity. We build four traditional machine learning models and two graph neural network models. Cross-comparison of the prediction performance and model accuracy was conducted among different models. The deeperGATGNN model exhibits high prediction accuracy and is used for predicting the heat capacity of 32,026 structures screened from the open quantum material database. We gain deep insight into the correlation between heat capacity and structure descriptors such as space group, prototype, lattice volume, atomic weight, etc. Twenty-two structures were predicted to possess high heat capacity, and the results were further validated with DFT calculations. We also identified one special structure, namely, MnIn 2 Se 4 , with space group no. 227 ( Fd 3̅ m ), that exhibits extremely high heat capacity, even higher than that of the Dulong-Petit limit at room temperature. This study paves the way for accelerating the discovery of novel thermal energy storage materials by combining machine learning with minimal DFT inquiry.

The paper is concerned with the study of structural disorder as well as the emergence and causes of heat capacity hysteresis in multiwall carbon nanotubes. The investigation methods are X-ray diffraction analysis, Raman spectroscopy, transmission electron microscopy, and calorimetric tests: thermogravimetric analysis, differential scanning calorimetry, and the thermal relaxation method for heat capacity hysteresis. Multiwall carbon nanotubes are shown to be composed of one or several types of zigzag-armchair domains. The domain structure of nanotube samples is responsible for the generation of uniaxial elastic microstrains and viscoelastic bending strains at domain interfaces. The thermomechanical behavior of interfaces is the chief cause of temperature hysteresis of heat capacity. The number of hystereses corresponds to the number of domain types in the structure, and values of hysteresis are determined by the crystallite size, thermal conductivity, and normal temperature distribution of strain. The found mechanism of heat capacity hysteresis can be helpful in preventing jumps in thermal properties and managing thermal memory in multiwall carbon nanotubes.

The thermodynamic properties for bcc-Fe were predicted by combination of the first-principles calculations, the quasiharmonic approximation, the CALPHAD method and the Weiss molecular field theory. The hybrid method considers the effects of the lattice vibration, electron, intrinsic magnetism and external magnetic fields on the thermodynamic properties at finite temperature. Combined with experimental data, the calculated heat capacity without external magnetic fields was used to verify the validity of the hybrid method. Close to the Fermi level the high electronic density of states leads to a significant electronic contribution to free energy. Near the Curie temperature lattice vibrations dominant the Gibbs free energy. The order of the other three excitation contributions to Gibbs free energy from high to low is: intrinsic magnetism > electron > external magnetic fields. The investigation suggests that all the excitation contributions to Gibbs free energy are not negligible which provides a correct direction for tuning the thermodynamic properties for Fe-based alloy., (© 2022 IOP Publishing Ltd.)

For this work, europium monosulfide (EuS) powders were prepared by sulfurizing Eu 2 O 3 powder with CS 2 gas. The synthesized EuS powders were sintered by SPS at temperatures in the 800-1600 °C range for 0.33-1 h at 50 MPa under vacuum conditions. The influences of Yb doping and sintering conditions on the magnetocaloric and mechanical properties of EuS were investigated systematically. An increase in sintering temperature caused the rise of lattice parameters of EuS, whereas Yb doping caused them to drop. SEM showed that the grain size of the EuS increased with sintering temperatures in the 1000-1400 °C range. Higher sintering temperatures can enlarge the magnetizability and saturation magnetization of EuS compact. On the contrary, Yb doping can weaken the magnetizability and saturation magnetization of EuS compact. All sintered polycrystalline EuS compacts had weaker thermomagnetic irreversibility and lower magnetic anisotropy.

Pavement surface temperature is of great significance to pavement performance and pavement design, as well as the development of cool pavements. The variation of a pavement surface temperature is complicated as it is jointly affected by various factors, including air temperature, solar irradiance, wind speed, and pavement texture. This study overviews the internal and external factors that affect the pavement surface temperature in the field. It is found that air temperature is the main external climatic factor affecting the pavement surface temperature during the course of a day. Although solar radiation dictates the thermal partition at the pavement surface, it mainly influences daytime pavement temperature but vanishes at night. Pavements in calm weather can be 3-10 °C hotter than those in windy weather, depending on the time of the day and the season. Other external factors such as passing vehicles also influence the pavement surface temperature at a degree 1-3 °C. Also, the shading effect of urban trees can affect pavement surface temperature and urban microclimate. Internal factors that vary pavement surface temperature include albedo, thermal conductivity, heat capacity, and emissivity. Among them, albedo controls the pavement surface temperature while other factors play a secondary role. The results of this review provide a scope of research for developing sustainable and advanced solutions for future municipal pavement construction and urban heat island (UHI) mitigation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Materials showing synergy of magnetic and dielectric transitions are promising candidates for future molecular devices. The challenge is how to realize synergy between spin and dielectric transitions with responses to external stimuli. Herein, we design a 2D spin crossover (SCO) complex, [Fe II (dpa)][(pzTp)Fe III (CN) 3 ] 2 (1) (dpa=1,2-bis(4-pyridyl)ethyne and pzTp=tetrakis(pyrazolyl)borate). The local structural changes about the Fe II ion were propagated to the whole crystal through the rigid bridging ligands (dpa), leading to elastic interactions to realize the abrupt SCO and rotational movements of polar apical pyrazolyl rings in the [(pzTp)Fe III (CN) 3 ] - units. Dielectric measurements confirmed a substantial dielectric change (Δϵ'=2.3) upon the spin transition. This work provides a rational strategy to couple the spin transition and rotation of polar components, which is crucial for the synergetic switch of magnetism and dielectricity., (© 2022 Wiley-VCH GmbH.)

Although the thermal conductivity of molten salt mixtures is of interest for many potential technological applications, precise values are often hard to obtain. In this study, the thermal diffusivity of FliNaK was studied in a molten state using the laser flash method and found to be very slightly dependent on temperature. The heat capacity of FliNaK was measured using the DSC method. There was a minor difference between our results and data from the literature. From calculations based on thermal diffusivity, density and heat capacity values, thermal conductivity was shown to decrease with temperature.

The thermal behaviour of crystalline and amorphous carvedilol (CAR) phases was studied by advanced thermal analysis using Quantum Design Physical Property Measurement System and Differential Scanning Calorimetry. Theoretical functions describing crystalline carvedilol heat capacity at low temperatures and the Debye-Einstein function for high temperatures were obtained. Based on the experimental heat capacity values, solid and liquid baselines were established, and the state functions (H, S, G) for solid and liquid states were calculated. A comprehensive characterization of melting and glass transition processes was obtained. CAR is easily amorphizable by cooling the liquid. The residual entropy, which quantifies the extent of frozen-in disorder in the amorphous solid, for glassy CAR was estimated as 51 J·mol -1 ·K -1 . The Kauzmann temperature (T K ) was estimated based on enthalpy and entropy. Molecular motions in the amorphous phase were also studied. The activation energy for structural relaxation (E a = 539 kJ·mol -1 ) and fragility parameter (m = 91) were obtained from the non-isothermal physical ageing. The isothermal physical ageing kinetics of amorphous CAR was studied by applying Kohlrausch-Williams-Watts (KWW) model. The mean molecular relaxation time constant (τ KWW = 117 min) and relaxation constant (β KWW = 0.33) were obtained. CAR was classified as a fragile glass-former. Furthermore, τ KWW constant for samples aged at 303.15 K is very low, thus, the physical ageing will occur during the short- and long-term storage of amorphous CAR, potentially changing its physicochemical properties during the ageing process. However, the results of molecular mobility studies (high molecular motions) show that the relationship between molecular motions in a glassy solid and its tendency to crystallization does not seem to follow an expected pattern, i.e., no crystallization occurred by thermal treatment of glassy, supercooled liquid and liquid phases of CAR as one would expect. Modern calorimetry and quantitative thermal analysis provided the fundamental kinetic and thermodynamic information about the crystalline and amorphous states of CAR., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Surprisingly, magnetoquantum oscillations (MQOs) characteristic of a metal with a Fermi surface have been observed in measurements of the topological Kondo insulator SmB 6 . As these MQO have only been observed in measurements of magnetic torque (dHvA) and not in measurements of magnetoresistance (SdH), a debate has arisen as to whether the MQO are an extrinsic effect arising from rare-earth impurities, defects, and/or aluminum inclusions or an intrinsic effect revealing the existence of charge-neutral excitations. We report here the first observation of MQO in the low-temperature specific heat of SmB 6 . The observed frequencies and their angular dependence for these flux-grown samples are consistent with previous results based on magnetic torque for SmB 6 but the inferred effective masses are significantly larger than previously reported. Such oscillations can only be observed if the MQO are of bulk thermodynamic origin; the measured magnetic-field dependent oscillation amplitude and effective mass allow us to rule out suggestions of an extrinsic, aluminum inclusion-based origin for the MQO., (© 2022 IOP Publishing Ltd.)