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The density, surface tension, and viscosity of liquid Zr76.0−xFe24.0Nbx (x = 6.6, 10.0, 15.0) alloys were measured by using the electrostatic levitation technique. The maximum undercooling achieved for these alloys was 151, 91, and 119 K, respectively. To evaluate the thermophysical properties in a wider temperature range, molecular dynamics simulations were performed by using the embedded atom method potential. Both measured and simulated results indicate that the liquid density increases linearly with decreasing temperature and also gradually rises with increasing Nb content. Additionally, the simulated and experimental results for surface tension and viscosity were analyzed. In all three alloys, surface tension increases linearly with decreasing temperature. The relationship between viscosity and temperature follows an Arrhenius-type equation, with both surface tension and viscosity increasing as the Nb content increases. The calculated results of density, surface tension, and viscosity are in good agreement with the experimental results. Furthermore, the specific heat, emissivity, and diffusion coefficient of liquid alloys were calculated. The specific heat for liquid Zr76.0−xFe24.0Nbx (x = 6.6, 10.0, 15.0) alloys is (36.47 ± 1.68), (35.20 ± 2.28), and (41.04 ± 3.73) J mol−1 K−1, respectively. Emissivity decreases linearly with temperature. The diffusion coefficient decreases, while the diffusion activation energy increases with a higher Nb content. [ABSTRACT FROM AUTHOR]

In experimental and theoretical studies of glass transition phenomena, one often finds a sharp crossover in dynamical properties at a temperature Tcr. A bifurcation of a relaxation spectrum is also observed at a temperature TB ≈ Tcr; both lie significantly above the glass transition temperature. In order to better understand these phenomena, we introduce a new model of glass-forming liquids, a binary mixture of prolate and oblate ellipsoids. This model system exhibits sharp thermodynamic and dynamic anomalies, such as the specific heat jump during heating and a sharp variation in the thermal expansion coefficient around a temperature identified as the glass transition temperature, Tg. The same temperature is obtained from the fit of the calculated relaxation times to the Vogel–Fulcher–Tammann (VFT) form. As the temperature is lowered, the calculated single peak rotational relaxation spectrum splits into two peaks at TB above the estimated Tg. Similar bifurcation is also observed in the distribution of short-to-intermediate time translational diffusion. Interrogation of the two peaks reveals a lower extent of dynamic heterogeneity in the population of the faster mode. We observe an unexpected appearance of a sharp peak in the product of rotational relaxation time τ2 and diffusion constant D at a temperature Tcr, close to TB, but above the glass transition temperature. Additionally, we coarse-grain the system into cubic boxes, each containing, on average, ∼62 particles, to study the average dynamical properties. Clear evidence of large-scale sudden changes in the diffusion coefficient and rotational correlation time signals first-order transitions between low and high-mobility domains. [ABSTRACT FROM AUTHOR]

We explore the phase behavior of a binary colloidal system under external spatially periodic modulation. We perform Monte Carlo simulations on a binary mixture of big and small repulsive Lennard-Jones particles with a diameter ratio of 2:1. We characterize structure by isotropic and anisotropic pair correlation functions, cluster size distribution, bond angle distribution, order parameter, and specific heat. We observe the demixing of the species in the absence of external modulation. However, the mixing of the species gets enhanced with increasing potential strength along with the alignment of the particles transverse to the modulation. The de-mixing order parameter shows discontinuity with increasing modulation strength, characterizing a first order phase transition. The peak in specific heat increases linearly with the size of the system. We also look into the dynamical behavior of the system via computing Mean Square Displacement (MSD) along both parallel and perpendicular directions to the modulation. We observe a decrease in the diffusion coefficient for both types of particles as we increase the strength of the modulation. [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]

For multi-layered 2D materials, although its c-axis has a much lower thermal conductivity than the a-axis, its phonon mean free path has been confirmed to be very long, e.g., in the order of 100s nm at room temperature for multi-layered graphene. An anisotropic specific heat concept has been proposed in the past to explain this very long mean free path. This work carries out detailed atomistic modeling to quantify the anisotropic specific heat concept and reports the discovery of anisotropic temperatures in multi-layered 2D materials under ultrafast surface heating. Extremely fast c-phonon energy transport is discovered, and the non-Fourier effect is observed for both a-phonons and c-phonons. The energy coupling factor between these two modes of phonons is determined to be in the order of 1016 W K−1 m−3, with the specific number depending on the structure location. The anisotropic temperature concept is also quantitatively confirmed based on the lattice Boltzmann method simulation. The anisotropic temperature concept does not violate the physics that temperature is a scalar; rather, it is developed to distinguish the temperatures of phonons that travel in different directions. This concept is universally applicable to other 2D materials to describe the heat conduction in the in-plane and out-of-plane directions that feature different interatomic bonds. [ABSTRACT FROM AUTHOR]

We study the geometrothermodynamics of black holes within the framework of the five-dimensional Einstein–Gauss–Bonnet (EGB) theory and its various extensions, including Einstein–Maxwell–Gauss–Bonnet (EMGB), the inclusion of a cosmological constant in EMGB and Einstein–Yang–Mills–Gauss–Bonnet (EYMGB). To expand the scope of our research, we utilize Tsallis entropy, an extended form of entropy that surpasses the traditional Boltzmann–Gibbs entropy. We first obtain the relations for the Hawking temperature, specific heat and scalar curvature in terms of Tsallis entropy and then show that incorporating Tsallis entropy into the description of black holes allows us to explore their thermodynamic characteristics beyond conventional limits, providing valuable insight into the stability of the black holes. We analyze that in the scenario of Tsallis entropy, the stability regions and phase transition points of specific heat coincide with the divergence points of scalar curvatures which confirm the consistency of the results. We also provide a comparative examination of our findings for the considered models of black holes. This comparative analysis deepened our understanding of the thermodynamic behavior exhibited by these diverse black holes within the extended EGB framework. [ABSTRACT FROM AUTHOR]

Due to the high viscosity and low fluidity of viscous crude oil, how to effectively recover spilled crude oil is still a major global challenge. Although solar thermal absorbers have made significant progress in accelerating oil recovery, its practical application is largely restricted by the variability of solar radiation intensity, which is influenced by external environmental factors. To address this issue, this study created a new composite fiber that not only possesses solar energy conversion and storage capabilities but also facilitates crude oil removal. PF@PAN@PEG was obtained by coaxial electrospinning processing, with PEG within PAN fibers, and a coating layer was applied to the fiber surface to impart oleophilicity and hydrophobicity. PF@PAN@PEG exhibited a high latent heat value (77.12 J/g), high porosity, and excellent photothermal conversion and oil storage capabilities, significantly reducing the viscosity of crude oil. PF@PAN@PEG can adsorb approximately 11.65 g/g of crude oil under sunlight irradiation. Notably, due to the encapsulation of PEG, PF@PAN@PEG can continuously maintain the crude oil at a phase change temperature by releasing latent heat under specific conditions, effectively reducing its viscosity with no PEG leakage at all. When solar light intensity varied, the crude oil collection efficiency increased by 21.99% compared to when no phase change material was added. This research offers a potential approach for the effective use of clean energy and the collection of viscous crude oil spill pollution. [ABSTRACT FROM AUTHOR]

The time period around the Noachian–Hesperian boundary, 3.7 billionyears ago, was an epoch when great geodynamical and environmental changes occurred on Mars. Currently available remote sensing data are crucial for understanding the Martian heat loss pattern and its global thermal state in this transitional period. We here derive surface heat flows in specific locations based on the estimations of the depth of five large thrust faults in order to constrain both surface and mantle heat flows. Then, we use heat-producing element (HPE) abundances mapped from orbital measurements by the Gamma-Ray Spectrometer (GRS) onboard the Mars Odyssey 2001 spacecraft and geographical crustal thickness variations to produce a global model for the surface heat flow. The heat loss contribution of large mantle plumes beneath the Tharsis and Elysium magmatic provinces is also considered in our final model. We thus obtain a map of the heat flow variation across the Martian surface at the Noachian–Hesperian boundary. Our model also predicts an average heat flow between 32 and 50 mW m − 2 , which implies that the heat loss of Mars at that time was lower than the total radioactive heat production of the planet, which has profound implications for the thermal history of Mars. [ABSTRACT FROM AUTHOR]

The rare-earth oxyborate crystal RCa4O(BO3)3 (RCOB, R: rare-earth elements) is an inorganic photoelectric multifunctional material, which has important applications in the field of high-temperature piezoelectricity. In this work, a EuCa4O(BO3)3 (EuCOB) crystal with a diameter of 25 mm was successfully grown by the Bridgman method. The thermal conductivity, thermal diffusivity and specific heat of the EuCOB crystal at high temperature were measured. The dielectric coefficient, electromechanical coupling coefficient, elastic coefficient and piezoelectric coefficient of the EuCOB crystal at high temperature were measured by the resonance–antiresonance method. In particular, the shear piezoelectric coefficient d26 of the EuCOB crystal is 7.01 pC N−1 at room temperature and 6.22 pC N−1 at 800 °C, with a small variation of 11.4%. The electrical resistivities of the EuCOB crystal along the X, Y and Z directions at 800 °C are 5.8 × 107 Ω cm, 3.1 × 107 Ω cm and 2.9 × 107 Ω cm, respectively. The large piezoelectric coefficient and high electrical resistivity indicate the potential application of the EuCOB crystal in a high-temperature piezoelectric field. [ABSTRACT FROM AUTHOR]

We present thermodynamic properties for liquid uranium obtained from classical molecular dynamics (MD) simulations and the first-principles theory. The coexisting phases method incorporated within MD modeling defines the melting temperature of uranium in good agreement with the experiment. The calculated melting enthalpy is in agreement with the experimental range. Classical MD simulations show that ionic contribution to the total specific heat of uranium does not depend on temperature. The density of states at the Fermi level, which is a crucial parameter in the determination of the electronic contribution to the total specific heat of liquid uranium, is calculated by ab initio all electron density functional theory (DFT) formalism applied to the atomic configurations generated by classical MD. The calculated specific heat of liquid uranium is compared with the previously calculated specific heat of solid γ-uranium at high temperatures. The liquid uranium cannot be supercooled below Tsc ≈ 800 K or approximately about 645 K below the calculated melting point, although, the self-diffusion coefficient approaches zero at TD ≈ 700 K. Uranium metal can be supercooled about 1.5 times more than it can be overheated. The features of the temperature hysteresis are discussed. [ABSTRACT FROM AUTHOR]

Highlights The self‐healing process in PCL (polycaprolactone)/epoxy blends is studied in order to optimize the healing process and understand its underlying mechanism. For this purpose, PCL/epoxy blends are prepared with and without multiwall carbon nanotubes (MWCNTs) addition. Three different self‐healing heat‐inducement techniques are used (an oven, Joule effect, and infrared (IR) lamp) as a function of healing time (2, 5, 10, and 15 min) and PCL concentration (5, 10, and 15 wt%). The results obtained demonstrate that the addition of MWCNTs to the polymer matrix in PCL/epoxy blends accelerates the self‐healing process, attributed to an improved heat diffusion in MWCNTs/PCL/epoxy blends. The best self‐healing results were obtained with the highest self‐healing time and concentration of PCL, caused by the higher probability of the crack formation over a PCL reservoir. The most efficient techniques to induce the self‐healing process in PCL/epoxy blends with and without MWCNTs are the conventional oven and the Joule Effect, respectively, being faster the latter method, as it induces a homogeneous internal heating of the material. Moreover, Joule effect can be controlled remotely, while IR radiation is a noncontact technique, which can be applied in situ. The three heating methods are evaluated considering these factors alongside their energy efficiency, establishing a method to choose a specific heating source for similar systems. PCL/epoxy blends reinforced with MWCNTs have been manufactured. Variable heating sources have been analyzed. The influence of the heating source on the self‐healing is studied. Joule constitutes the faster heating for MWCNTs/PCL/epoxy system. [ABSTRACT FROM AUTHOR]

Ultrasonic testing is a popular non-destructive method for characterising engineering materials and detecting their properties. Diverse quantities of sulphur are incorporated into an uncured rubber compound, which is subsequently cured under specific pressure and heat conditions to attain the desired properties in the final product. The present work represents a quantitative estimation of sulphur content for cured NBR (Nitrile Butadiene Rubber) samples by an ultrasonic approach. The experiments have been conducted using cured NBR samples with varying sulphur content, ranging from 0% to 1.34%. Ultrasonic pulse behaviour at different temperatures (30°C to 160°C) has been observed using an ultrasonic setup which has been developed in-house. A-scan data is obtained at a sampling rate of 80 MHz using an 18 mm diameter broadband transducer with a 1 MHz central frequency. The ultrasonic longitudinal velocity (ULV) of rubber is determined from A-scan data using time-of-flight, and sulphur content has a significant impact on the ULV. At a temperature of 160°C, the ultrasonic longitudinal velocity (ULV) is measured at 1262 m/s for a sample with 0.62% sulphur content, and at 1321 m/s for a sample with 1.34% sulphur content. [ABSTRACT FROM AUTHOR]

The development of new materials showing the magneto-caloric effect (MCE) requires fast and reliable characterization methods. For this purpose, a phenomenological model developed by M. A. Hamad has proven to be a useful tool to predict the magnetocaloric properties (the isothermal magnetic entropy change, Δ S M , the magnetization-related change of the specific heat, Δ C P , H , and the relative cooling power, RCP) via calculation from magnetization measurements as a function of temperature, M(T). However, fitting the M(T) data is difficult for broad, smoothed-out transition curves which are often observed for material systems such as core-shell nanoparticles, nanowires, nanowire fabrics or nanoparticle hybrid materials. Thus, in this contribution we present a different approach enabling proper fitting of such magnetization data via the use of an asymmetric Boltzmann sigmoid function, which provides a clear physical background and enables to properly describe the broad and smoothed out transitions of nanomaterials. As examples for our procedure, we present fits to M(T) curves of polycrystalline, bulk La 0.67 Ba 0.33 MnO 3 as well as La 1 - x Sr x MnO 3 ( x = 0.2, 0.3, 0.4) and La 0.7 Ca 0.3 MnO 3 nanostructured materials from various authors. [ABSTRACT FROM AUTHOR]

This study investigates the temperature-dependent elastic, mechanical, thermal, and acoustic features of alkaline earth semiconductors calcium monochalcogenides CaX (X = S, Se, Te). First of all, the second- and third-order elastic constants have been calculated in the temperature range 0–500 K using the Born-potential model. The evaluated SOECs values were utilized to compute the mechanical constants at 0 K and 300 K. Selected materials in the present investigation have been found mechanically stable and brittle, in nature. The elastic anisotropy of the mechanical moduli has been presented using the 3D surface. SOECs have also been employed to perceive the acoustical wave velocities for longitudinal and shear modes of propagation and Debye mean velocities along <100>, <110>, and <111> directions. SOECs and TOECs were used to calculate the acoustic Grüneisen parameters. Further, the Debye characteristic temperature, thermal conductivity, specific heat, and energy density were computed for CaX. Finally, the direction-dependent ultrasonic attenuation due to phonon–phonon interaction and thermelastic relaxation process has been computed for CaX at room temperature. The results obtained have been validated with existing results that are accessible for the chosen materials. [ABSTRACT FROM AUTHOR]

This study proposes a modification to the two-stage cascade vapor compression refrigeration system by adding internal heat exchangers that function as subcoolers and desuperheater. The influence of each internal heat exchanger proposed on the exergy destruction rate, exergy efficiency, compressor power consumption, ECOP, and COP of the system was investigated. Additionally, various refrigerant combinations were considered as working fluids to evaluate which combination is the most suitable for the proposed system. Mathematical models based on the principles of thermodynamics were established in Engineering Equation Solver (EES), a software used for energy and exergy analysis. The results reveal that the addition of specific internal heat exchangers causes either an increase or decrease in overall system performance, depending on the type of refrigerant combination used. Consequently, there exists an optimal system configuration for each refrigerant combination. Compared with the conventional two-stage cascade refrigeration system, the optimal system configurations in the present study exhibited higher overall system performance. A maximum increase in exergy efficiency, ECOP, and COP of 7.31 %, 9.8 %, and 7.3 %, respectively, can be observed with the refrigerant combination R450A/R404A. Additionally, the results of the exergy analysis identify that the HTC compressor, condenser, LTC compressor, and cascade condenser are the primary contributors to the exergy destruction rate within the system. [ABSTRACT FROM AUTHOR]

Thermophysical properties encompassing specific heat, thermal conductivity, thermal diffusivity and thermal expansion and their temperature dependence is most sought after during selection of materials for various engineering applications. In this review a broad perspective on the thermal transport in metals and alloys, thermal energy carriers and factors affecting their mean free path is presented. Following the discussion on thermal transport, various techniques available for measuring thermal diffusivity, their principle of detection, merits and demerits are deliberated with an emphasis on laser flash analyzer. Theory of laser flash analysis, possible causes for deviation in the theoretical assumptions that affect the accuracy of measured diffusivity and ways and means of improving the same is dwelt upon. Finally, few typical case studies on thermal diffusivity measurements covering broad spectrum of materials differing in chemistry, degree of deformation, and heat treatment conditions are presented to demonstrate the sensitivity of thermal diffusivity to microstructural changes in materials. [ABSTRACT FROM AUTHOR]

In this, we report the temperature-dependent magnetization [M(T)] in two distinct magnetic fields of 0.5 T and 5 T for Ni47Mn40−xSixIn3 (x = 1, 2, and 3) alloys. Using a phenomenological model and Maxwell's thermodynamic relation, the values of the magnetic entropy change and specific heat capacity are calculated, and their values are also compared. The maximum magnetic entropy change and specific heat capacity peak values for different magnetic fields are both steadily reduced for the samples with x = 1 to 3 samples, which is followed by an increase in relative cooling power value. In comparison to 0.5 T magnetic field, the samples investigate the highest values of magnetic entropy change (3.32, 2.81, 2.01 J kg−1 K−1) and specific heat capacity (32.37, 14, 4.32 J kg−1 K−1) with a magnetic field of 5 T. According to this finding, the sample is more responsible for the magnetic field than chemical pressure. [ABSTRACT FROM AUTHOR]

The growth, ion concentrations, powder X‐ray diffraction, thermal properties, and optical spectroscopy of Nd3⁺‐doped Ca₃(BO₃)₂ single crystals are investigated. The Nd3+‐doped Ca₃(BO₃)₂ single crystals with 1.97 at.% Nd3⁺ are successfully grown using the Czochralski (Cz) technique. To address the chemical valence imbalance between Nd3⁺ and Ca2⁺ in the Ca₃(BO₃)₂ crystals, the Na⁺ ions are introduced. The concentrations of Nd3⁺ and Na⁺ ions in the as‐grown crystals are measured using inductively coupled plasma atomic emission spectroscopy (ICP‐AES), yielding concentrations of 1.97 at% (N0 = 1.55 × 1020 cm−3), 1.94 at% (N0 = 1.52 × 1020 cm−3), respectively. The thermal behavior of the Nd3⁺‐doped Ca3(BO3)2 crystals, including thermal expansion coefficients, specific heat, and thermogravimetric and differential thermal analysis (TG‐DTA), is systematically investigated. At room temperature, the polarized absorption spectra, polarized fluorescence spectra, and fluorescence decay lifetimes are measured. Spectral parameters, including polarized absorption and stimulated emission cross‐sections, intensity parameters, transition probabilities, radiative lifetime, and branching ratios are determined using the Judd‐Ofelt (J‐O) theory. The results indicate that Nd3+‐doped Ca3(BO3)2 crystals are promising materials for near‐infrared lasers, offering advantages such as rapid growth, large size, high specific heat, strong emission, and environmental stability. [ABSTRACT FROM AUTHOR]

Syntactic foams are lightweight porous composites obtained by the addition of hollow glass microspheres (HGMs) to a polymer matrix. This work experimentally and numerically investigates the thermal behavior of epoxy‐based syntactic foams with enhanced multifunctionality produced by incorporating microencapsulated phase change materials (PCMs) as functional fillers, providing thermal energy storage and temperature stabilization due to its large latent heat of melting. Foams are fabricated using varying ratios of HGMs (0–40 vol%) and PCM (0–40 vol%) to achieve tuned densities and thermal properties with a total filler content of up to 40 vol%. A one‐dimensional numerical heat transfer model based on the enthalpy method is presented to simulate the thermal behavior of these materials. The model accurately incorporates the specific heat and thermal conductivity of the foam components, as well as the latent heat absorption during PCM melting (up to 68 J/g). The model is experimentally validated by demonstrating good agreement with the measurements of transient temperature profiles during heating tests on the foam samples. The validated tool is then leveraged to model the thermal response of the foams under a sinusoidally varying heat source, similar to the possible real applicative scenarios. These results can help optimize foam compositions balancing energy storage density, heat transfer properties, and structural support for lightweight energy storage systems. Potential applications include high‐efficiency thermal management in battery packs, electronic cooling, solar energy storage, and sustainable temperature‐controlled buildings. Highlights: Foams with 0–40 vol% PCM and 0–40 vol% HGM show up to 68 J/g latent heat.1D numerical model accurately captures thermal conductivity and PCM phase change.Validated model simulates thermal response under sinusoidal heat, optimizing foam composition.Foams act as thermal reservoirs, maintaining up to 5°C lower surface temperatures than epoxy. [ABSTRACT FROM AUTHOR]

We study an exotic Kondo effect in a system consisting of two one-dimensional XX Heisenberg ferromagnetic spin-1/2 chains (denoted by α = u , d for up and down chains) coupled to a quantum dot consisting of two localized spin-1/2 magnets. Using the Jordan–Wigner transformation on the Heisenberg Hamiltonian of the two chains, this system can be expressed in terms of non-interacting spinless fermionic quasiparticles. As a result, the Hamiltonian of the whole system is expressed as an Anderson model for spin-1/2 fermions interacting with a spin-1/2 impurity. Thus, we study the scattering of fermionic quasiparticles (propagating along spin chains) by a pair of localized magnetic impurities. At low temperature, the localized spin-1/2 magnets are shielded by the chain "spins" via the Kondo effect. We calculate the Kondo temperature T K and derive the temperature dependence of the entropy, the specific heat and the "magnetic susceptibility" of the dot for T ≫ T K. Our results can be generalized to the case of antiferromagnetic XX chains. [ABSTRACT FROM AUTHOR]

Microwave energy is based on creating heat in the structure by creating vibrations in the moisture in the product used. In drying processes, drying kinetics, energy consumption, quality, and so on features are evaluated based on the temperature equivalent of the heat created by the heat source in the product. For this reason, the temperature value formed in the product in microwave drying processes is important. In this study, the effects of microwave drying powers (180, 540, 720, and 900 W) on the surface temperature profile, drying kinetics, thermophysical properties, and color values of peach slices were investigated. For drying processes performed at 180, 540, 720, and 900 W microwave powers, the surface temperatures of peach slices were 34.5–83.40, 49.60–89.60, 55.90–94.06, and 68.20–145.20°C, respectively. Effective diffusion values varied between 1.01 × 10−7 and 2.12 × 10−7, and the activation energy value was measured as 20.73 kJ/mol. Specific heat values varied between 871.62 and 838.21 J/kg K, density values varied between 839.41 and 697.93 kg/m3, thermal diffusivity values varied between 5.69 × 10−7 and 2.344 × 10−7 m2/s and thermal conductance values ranged between 0.44 and 0.08 W/m K. As compared to the fresh fruits, the best color values of dried material were achieved at 720 W microwave power. It is recommended to determine the microwave drying power value well and to determine the drying kinetic properties of each agricultural product specifically for the product. [ABSTRACT FROM AUTHOR]

The study aims to fill the gap in the existing literature by investigating the effects of various tool materials, including copper, tungsten carbide, and brass, on performance parameters in electric discharge machining (EDM) simulations. The authors developed a modified gaussian heat flux equation that incorporates the electrical resistivity of both the tool and workpiece, based on prior experimental investigations. The authors further developed a finite element model that incorporates the modified Gaussian heat flux equation, spark radius, and fraction of heat transferred to workpiece as a function of pulse on time and pulse current, latent heat, specific heat values, and thermal conductivity properties. The outcomes of the simulation indicated that the Cu tool exhibited the minimum MRR and SR values when subjected to a current of 9 amps and a duty cycle of 0.4, as well as a current of 12 amps and a duty cycle of 0.6. The results also indicate that the brass tool displayed marginally elevated MRR and SR, whereas the Tungsten carbide tool exhibited the highest MRR and SR. The simulation results for all three tool materials showed similar trends, consistent with prior research. Also, an increase in gap voltage, pulse current and duty cycle was observed to correspond with increased MRR and SR. Authors also observed that as electrode material electrical conductivity increased, so did workpiece material residual stresses. These results assist with the choice of tool materials for EDM processes, allowing for finer control over performance parameters and greater machining efficiency. [ABSTRACT FROM AUTHOR]

Based on the bond energy model, we investigate the particle size and shape effects on the melting temperature, Debye temperature, and specific heat at constant pressure of Ni nanoparticles with carbon impurity. We have derived analytical expressions for these thermodynamic quantities as functions of the size and shape of nanoparticles. Numerical calculations have been implemented for nickel nanoparticles with carbon impurity up to 20 nm of size. Our theoretical melting temperatures are compared with molecular dynamics simulations showing the good agreement. Our research indicates that the Debye temperature and melting temperature of nickel nanoparticles increase rapidly while the specific heat decreases significantly for particle diameters smaller than 5 nm. At larger sizes, these thermodynamic quantities gradually approach saturation values of bulk material. This indicates that surface area plays an important role in the thermodynamic properties of nickel nanoparticles. And carbon substitution leads to a reduction in the values of the studied thermodynamic quantities. [ABSTRACT FROM AUTHOR]

This research investigates the complex statistical behavior of fermion-antifermion pairs within a (2+1)-dimensional magnetized Bonnor-Melvin background affected by non-zero cosmological conditions. The Bonnor-Melvin magnetic universe model, known for its cylindrical symmetry, preserves the invariance of quantum field dynamics under Lorentz boosts along the z -axis. This framework facilitates the examination of (2+1)-dimensional scenarios, where the corresponding spacetime background is identified as the Bonnor-Melvin magnetic 2+1+0-brane solution within the realm of gravity coupled with nonlinear electrodynamics. Initially, the precise energy spectra of these pairs are summarized using an analytical solution derived from the fully covariant two-body Dirac equation. Subsequently, the statistical properties inherent in these pair formations are investigated. These findings may illuminate the interplay among magnetic fields, spacetime geometry, and the cosmological constant, thereby enhancing our comprehension of the fundamental behaviors of fermions amidst intricate cosmological conditions. It is anticipated that this investigation could offer new insights into the statistical attributes of fermion-antifermion systems. All thermal characteristics, including free energy, total energy, entropy, and specific heat, have been computed. The impact of diverse factors, such as magnetic fields, spacetime geometry, and the cosmological constant, on these characteristics has been scrutinized. [ABSTRACT FROM AUTHOR]

In cold, moisture-rich winter environments, window fogging represents a substantial safety hazard for drivers. Electric vehicles often incorporate heat pump systems to address challenges such as dehumidification and heating specific to cold weather. Therefore, it is essential to evaluate the dehumidification and heating efficiency of these systems through focused research. This study presents a dual-evaporator heat pump system designed specifically for electric vehicles, equipped with two distinct modes for dehumidification and heating. The research examines how factors such as inlet air volume and the degree of opening of the electronic expansion valve affect the system's dehumidification and heating performance. Experimental analyses were conducted to explore the system's response under various conditions of inlet air humidity and compressor speed in both modes. Results suggest that increasing inlet air volume improves dehumidification effectiveness but may reduce heating performance. Likewise, a wider opening of the electronic expansion valve enhances heating but could decrease dehumidification efficiency. Importantly, the study indicates that when the relative humidity of the inlet air exceeds 70 %, a single evaporator mode is more effective for dehumidification. However, when the relative humidity is below 70 %, the dual evaporator mode is more advantageous, showing better heating performance. [ABSTRACT FROM AUTHOR]

Common ordinary fluids including water, glycol, and oils are extensively employed in solar thermal applications. However, because of their poor thermal performance and limited thermal conductivity, these fluids limit heat transfer. Hybrid nanofluids have proven themselves as a new and highly useful alternative because of their enhanced thermophysical characteristics in solar thermal applications. Recently, the focus in studies on hybrid nanofluids have increased as a continuation of the study of mono nanofluids. An extensive analysis of hybrid nanofluids research is presented in this review. This review focuses on the methods by which hybrid nanofluids is prepared as well as techniques to improve stability. Numerous studies have examined how hybrid nanoparticles affect thermophysical characteristics as density, viscosity, specific heat, and thermal conductivity. In this review, hybrid nanofluids were investigated as operating fluid in flat plate solar collector by a thorough examination of numerous theoretical, computational, and experimental research. The main objective of HNF application is to increase thermal efficiency. Ultimately, issues and limitations were covered, and suggestions for further research were provided. The results of the studies showed that water is the most suitable base liquid for use compared to other types of base liquids. As for nanoparticles, MWCNT and h-BN when mixed with metal oxides such as TiO2 and Al2O3 are the most suitable for use. [ABSTRACT FROM AUTHOR]

The high-speed steel Z80WCV 18-04-01 is highly valued in intensive machining for its exceptional characteristics such as high hardness and heat resistance. Composed of carbon, chromium, tungsten, and vanadium, this steel is particularly suitable for manufacturing cutting tools such as lathe tools, milling cutters, drills, and taps. The cumulative tempering process plays a crucial role in enhancing these properties, directly influencing the performance and durability of turning tools. This research aims to evaluate the effects of different tempering treatments on Z80WCV 18-04-01 high-speed steel turning tools, focusing on hardness, toughness, and microstructural changes, tempering involves heating the steel to a specific temperature below its critical point and then cooling it, which modifies its internal structure to achieve desired mechanical properties. By varying the tempering temperature and duration, researchers can tailor the steel's hardness and toughness to optimize performance in cutting applications. Understanding these changes is essential for developing tools that can withstand the demanding conditions of industrial machining processes, the microstructural analysis will provide insights into how the steel's grain size, carbide distribution, and phase composition evolve with different tempering treatments. [ABSTRACT FROM AUTHOR]

This research delved into the energetic properties of catalysts synthesized from residual sludge from the textile, galvanic, and tannery industries. The experimental process consisted of an initial heat treatment to activate their catalytic properties and a thermal analysis employing differential scanning calorimetry (DSC). This technique permitted the investigation of the materials' thermal behavior as a function of temperature, ranging from 142 to 550 °C, effectively controlling the heating rates and pressure conditions. The data gathered were the input for constructing specific heat models through polynomial regression employing the least squares method. These models were subsequently used to estimate variations in the enthalpy and entropy for both the sludge and catalysts through integration. Third-degree polynomials primarily characterized the specific heat models that accurately represented the samples' thermal behavior, considering variations in their physicochemical properties that influenced it. The catalysts derived from residual sludge from the textile industry exhibited the models with the most robust statistical fit. Concurrently, the catalysts from the galvanic industry displayed noteworthy similarities with the bibliographic data across various temperature points. The mathematical models determined the specific heat (Cp) as a function of temperature, which, in turn, was used to estimate the enthalpy and entropy variations in the sludge and catalysts under study. The highest enthalpy value corresponded to the sludge and catalyst obtained from the tannery industry, with a Cp of 5.60 J/g-K at 603 K and 2.45 J/g-K at 445.6 K. Finally, the third-degree polynomials showed the best mathematical models since (1) they considered the variations in the physicochemical properties that intervened in the behavior of Cp as a function of temperature; (2) they presented a better statistical fit; and (3) they showed consistency with the existing information in the literature for the textile industry and the galvanic industries. [ABSTRACT FROM AUTHOR]

In the present article, the creation of a 3D glassy state by gradient thermal history distributed in a monolithic Zr50Cu40Al10 metallic glass using the proposed thermal gradient treatment is discussed. In this thermal method, a rod sample is annealed while sandwiched between BeCu25 jigs and cooled down by tilting contact against a liquid nitrogen‐cooled Cu mesh. This allows one side of the edge of the rod sample to cool down rapidly from the supercooled liquid region and introduce a temperature/cooling rate difference in 3D in a single process. Specific heat measurement, indentation test and evaluation of incubation time for crystallization reveal creation of 3D gradients throughout the whole sample. In the present study, a new technique of creating a 3D heterogeneity of glassy state to the desired distribution by gradient thermal history in metallic glasses will be promoted, and the development of functionally graded monolithic bulk metallic glasses will be encouraged in near future. [ABSTRACT FROM AUTHOR]

In this study, we analyze the mass spectra of meson systems within an N -dimensional space using the Killingbeck potential combined with an inversely quadratic potential. We employ the Nikiforov–Uvarov method along with the Pekeris approximation scheme to account for the centrifugal barrier. This approach enables us to compute numerical energy eigenvalues, normalized eigenfunctions, and mass spectra for both heavy and heavy–light meson systems. We explore various scenarios of the potential and find that the resulting energy eigenvalues are consistent with those obtained through previous analytical methods and experimental data. Additionally, we compute the thermodynamic properties of quarkonium particles, including mean energy, specific heat, free energy, and entropy. Furthermore, we investigate the effects of temperature and the dimensional number on meson masses and thermodynamic properties, providing valuable insights into the behavior of meson systems under different conditions. [ABSTRACT FROM AUTHOR]

This article presents mechanical and thermal characterisation of unidirectional glass/epoxy (GE) and GE composites with graphene nanoplatelets (Gp-GE) fabricated using the hand lay-up method followed by compression moulding. The content of graphene nanoplatelets varied is 0.1, 0.3, 0.5 and 0.7 wt%. The obtained material properties are required to analyse the response of cylindrical shells under thermo-mechanical loads such as internal pressure and thermal loading in the thickness direction. The cylindrical shell models consist of multilayers of continuous fibre composites with varying Gp content in each layer. Tensile tests are performed to measure the longitudinal (E1), transverse (E2) and shear modulus (G12), as well as the modulus with 45° fibre orientation. The effective moduli of the Gp-GE composites are predicted using modified Halpin-Tsai and the Rule of Mixtures (RoM) and compared with the experimental data. The through-the-thickness thermal conductivity ($k$ k) and specific heat (${C_p})$ C p) are measured using Light Flash Apparatus (LFA). The increments in E1, E2 and G12 are 24%, 143.9% and 13.8%, respectively, and the properties $k$ k and ${C_p}$ C p improved by 11.7% and 13.4%, respectively, as compared to GE composites. Finally, empirical relations are established for different moduli, $k$ k , and ${C_p}$ C p as a function of Gp content. [ABSTRACT FROM AUTHOR]

One of the barriers to the rapid transition of societies toward a more sustainable future is a scarcity of field experts. Members of scientific and professional communities believe that this obstacle could be overcome by supplementing the decisions of non-experts with artificial intelligence. To examine this opportunity, this study examines the viability of GPT-3.5 as an expert adviser in the energy management of kindergartens. Thus, field experts investigated the deductive and inductive reasoning potential of GPT-LLM (Large Language Model). The first task was conducted on a sample of kindergartens in the Western Balkans. The LLM was instructed to provide the buildings' specific heat consumption (SHC) by relatively detailed building descriptions and building occupancy. The second task involved kindergartens in various European locations, and the LLM was tasked with estimating energy savings using limited data about the renovation process. The study found deductive reasoning to be insufficient for estimating SHC from the building envelope details, with average accuracy below the least predictive model (R2 = 0.56; MAPE = 48%). Including the factor of occupancy, the SHC estimates were relatively accurate, wherein the first deductive test proved precise (MAPE = 27%), but it was less so in the opposite case (MAPE = 67%). In terms of inductive reasoning, the LLM assumptions were relatively consistent with practice. [ABSTRACT FROM AUTHOR]

The high-entropy alloy (HEA) has recently attracted significant interest due to its novel alloy design concept and exceptional mechanical properties, which may exhibit either a single or multi-phase structure. Specifically, refractory high-entropy alloys (RHEA) composed of titanium, niobium, and nickel-based HEA demonstrate remarkable mechanical properties at elevated temperatures. Additive manufacturing (AM), specifically Direct Energy Deposition (DED), is efficient in fabricating high-entropy alloys (HEA) owing to its fast-cooling rates, which promote uniform microstructures and reduce defects. This study involved the fabrication of the Ti33Nb28Cr11V11Ni17 (Ti-Nb-Cr-V-Ni) RHEA utilizing DED. Additionally, the post-processing of the fabricated alloy is conducted using conventional machining (CM) and laser-assisted machining (LAM). The results indicate thermal conductivity and specific heat increased, whereas tensile strength reduced with rising temperature. Significant softening was observed above 800 °C, resulting in a considerable decrease in tensile strength. Furthermore, the LAM caused material softening and reduced the cutting force by 60.0% relative to CM. Furthermore, the chemical composition of Ti-Nb-Cr-V-Ni remained unaffected even after post-processing with CM and LAM. The research indicates that post-processing with LAM is essential for developing resilient RHEA for practical use. [ABSTRACT FROM AUTHOR]

The macrokinetic characteristics of combustion of the quaternary Ti-Zr-B-C mixture as well as the mechanism and stages of phase formation for the synthesis products were investigated. The mechanical and thermophysical properties of the hot-pressed boride/carbide ceramics with eutectic composition (Ti,Zr)B 2 -43%at.(Zr,Ti)C were measured. Preliminary mechanical alloying (MA) of the (Zr + Ti) mixture was shown to yield Ti/Zr granules having a laminar structure and consisting of alternating layers of titanium, zirconium, and (Zr,Ti) ss solid solution. The method used to prepare reaction mixtures and the initial temperature T 0 increased within the range of 20–370 °C have virtually no effect on combustion temperature, which is 2260–2400 °C, while higher T 0 increases the combustion rate by a factor of 1.5–2. The use of MA Ti/Zr granules reduces the combustion rate as well as the specific heat release amount and the heat release rate. Time-resolved X-ray diffraction data showed that binary carbides (Zr 1-x Ti x)C and diborides (Ti 1-y Zr y)B 2 of variable stoichiometry are formed in the combustion wave of the Ti-Zr-B-C reaction mixtures within less than 0.25 s. The carbide and diboride phases are formed simultaneously; the use of MA Ti/Zr granules in the reaction mixtures reduces the content of solid solutions of variable stoichiometry among the reaction products. The ceramics fabricated using a combination of combustion synthesis and hot pressing have a dense and homogeneous structure that consist of bonded grains of the diboride (Ti 0.80 Zr 0.20)B 2 and carbide (Zr 0.83 Ti 0.17)C phases having the following properties: density, 5.3 g/cm3; hardness, 22.9 GPa; fracture toughness, 4.7 MPa m0.5; heat capacity, 0.52 J/(g·K); thermal diffusivity, 11.67 mm2/s; and thermal conductivity, 33.28 W/(m·K). [ABSTRACT FROM AUTHOR]

In this study, we explore various essential aspects of a noncommutative theory that incorporates space deformation. Through the Extended Gravitational Decoupling (EGD) approach within the Strong Energy Condition (SEC), we investigate the gravitational decoupling method to obtain static black hole solutions that satisfy Einstein's field equations with a vacuum tensor. The analysis concentrates on the thermodynamics of the static solution, examining and deriving expressions for various thermodynamic quantities. This investigation explores how temperature, free energy, and specific heat depend on the horizon radius, considering different values for both hairy and noncommutative parameters. The study suggests that thermodynamically, smaller hairy black holes exhibit greater stability compared to larger ones. It also reveals a nontrivial relationship between the horizon radius, temperature range, and specific values of the hairy parameters for static hairy black holes when considered in thermodynamic equilibrium with their Hawking radiation. The discussion extends to the implications of the first law of black hole thermodynamics in the context of the noncommutative hairy case. [ABSTRACT FROM AUTHOR]

The search for spin-reorientation (SR) phase transitions, a spontaneous rotation of ordered magnetic moments, in ferrimagnetic (FiM) materials, which carry a net magnetization, is of fundamental and practical interest for applications in the field of spintronics. In this work, we have investigated Mn self-doped (Er 0.7 Mn 0.3)MnO 3 solid solution with GdFeO 3 -type Pnma perovskite structure by combining specific heat, magnetic susceptibility and neutron powder diffraction measurements. We provide experimental evidence for FiM order below T C = 104 K, and a spontaneous SR transition at T SR = 11 K. A FiM structure appears in all (R 1-x Mn x)MnO 3 compounds with R = Dy–Lu for x ≥ 0.2. But in this structural family, R = Er is the only material with a SR transition. FiM order in (Er 0.7 Mn 0.3)MnO 3 appears with ferromagnetic (FM) ordering of Mn3+ and Mn4+ cations at the B site along the a -direction, which are antiferromagnetically (AFM) coupled with Er3+ and Mn2+ cations at the A site. At T SR , ordered Er3+ change direction from the magnetically harder a -axis to the magnetically easy b -axis and induce a change of the whole FiM structure, including the direction of all Mn spins from the irreducible representation m GM3+ to m GM4+. We calculated the crystal-field (CF) anisotropy for Ho3+ in (Ho 0.8 Mn 0.2)MnO 3 and Er3+ in (Er 0.7 Mn 0.3)MnO 3 , based on the point charge model; the results revealed large magnetic anisotropies. For the FiM structure of (Ho 0.8 Mn 0.2)MnO 3 , the magnetically easy a -axis of Ho3+ keeps the high-temperature magnetic directions along the a -axis and gives rise to a pronounced magnetization reversal effect at low temperature because of a significant rise of Ho3+ ordered moments. On the other hand, for the FiM structure of (Er 0.7 Mn 0.3)MnO 3 , the magnetically easy b -axis of Er3+ gives rise to a SR phase transition at T SR , which does not lead to magnetization reversal even though Er3+ ordered moments rise significantly at low temperatures. [ABSTRACT FROM AUTHOR]

A large uniaxial negative thermal expansion (NTE) along the c-axis has recently been observed in the transition metal (Tr) zirconides TrZr2 with a tetragonal CuAl2-type structure. A recent study on FeZr₂ [M. Xu et al., Nat. Commun. 14, 4439 (2023)] suggests that optical phonons play a critical role in inducing the NTE along the c-axis. In this study, we investigate the thermophysical properties of TrZr₂ compounds (Tr = Fe and Co1− xNix(x = 0, 0.2, 0.4, 0.6, 0.8, 1)) using specific heat measurements, sound velocity data, and theoretical phonon calculations to achieve our aim of clarifying the contribution of optical phonons to the uniaxial NTE along the c-axis observed in both FeZr₂ and CoZr₂. We found that FeZr2 shows a lattice-specific heat peak structure at 8.90 meV, which corresponds to optical phonon energy with a high population of negative Grüneisen parameter along the c-axis in the phonon dispersion curves in FeZr2. In an examination of a chemical substitution effect on the Co1− xNixZr2, we found that the lattice-specific heat peak structure disappeared for x ≥ 0.4 and the oscillator intensity decreased. Phonon calculations revealed the existence of low-energy optical phonon branches at the Γ point for CoZr2 and FeZr2 with uniaxial NTE along the c-axis. However, the low-energy phonon branches were not found in NiZr2 with uniaxial positive thermal expansion along the c-axis. The increase in phonon density of states near the above optical phonon energy in CoZr2 and FeZr2 is consistent with the lattice-specific heat analyses, and we propose that low-energy optical phonons are essential for the exhibiting of uniaxial NTE along the c-axis in TrZr2. [ABSTRACT FROM AUTHOR]