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In this study, a technique to estimate the thermal properties of a suspended copper wire using the 3ω method was proposed and its operation was demonstrated. This approach used a digital multimeter with a large measurement buffer to implement a procedure in which an appropriate window function and a discrete Fourier transform (DFT) were applied. This significantly reduces the noise level to a few nV, especially in the lower-frequency regions (less than 1 Hz), even if a longer measurement time is required. The third-harmonic voltage signal containing the thermal properties information for the 3ω method was clearly observed with a high signal-to-noise (S/N) ratio, and the thermal conductivity and diffusivity were estimated from 60 K to 300 K from the current frequency dependence of the third-harmonic voltage. The thermal conductivities of the copper wire were determined to be 423.0 and 385.9 W/mK at 100 and 300 K, respectively. Specific heat was calculated from thermal conductivity and diffusivity, and the Debye temperature was estimated to be 346 K from the temperature dependence of the specific heat. These values were in good agreement with previous research. Measurement of thermal properties using a digital lock-in amplifier with identical configuration resulted in overestimation of thermal conductivity in entire temperature regions owing to a low S/N ratio throughout the analysis of the DFT. The technique based on DFT with a window function is therefore more reliable for detecting the third-harmonic voltage in the low-frequency region of less than 1 Hz because it obtains a high S/N ratio. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) can absorb, store, and release substantial latent heat within a specific temperature range during phase transition and have gained huge attention due to environmental concerns and energy crises. However, PCMs have a significant downside in energy storage due to their relatively lower thermal conductivity, leading to inadequate heat transfer (HT) performance. The foremost aim of the research is to synthesize an eco‐friendly coconut shell biochar (CSB) dispersed with organic A46 PCM in the temperature range of 44°C to 46°C to form a green nanocomposite. A two‐step approach is adopted to formulate the nanocomposites with different weight concentrations (0.2% and 0.8%) of green CSB particles. The developed nanocomposite's thermal conductivity and chemical stability were examined using a thermal properties analyzer and a Fourier transforms infrared spectrometer. The developed biochar composites have excellent thermal conductivity (0.39 W/m K) compared with base PCM (0.22 W/m K). Also, the developed nanocomposites were physically mixed together; there were no additional functional groups formed compared to pristine PCM, and the prepared materials were composite. Furthermore, a numerical analysis was performed using two‐dimensional energy modeling software to ascertain the HT rate of A46 composites. These thermally energized green nanocomposites show great promise for thermal energy storage and thermal management applications like battery thermal management, photovoltaic thermal systems, desalination systems, electronic cooling, building applications, and textiles. [ABSTRACT FROM AUTHOR]

In Iraq, certain rocks called porcelanite can be used to make lightweight concrete. The objective of this paper is to create lightweight self-compacting concrete (SCC) by utilizing 0.4 w/cm, coarse and fine porcelanite aggregate and adding nano silica to these mixtures. This study looks at a different way of doing things. Instead of using sand in concrete, they used varying amounts of fine porcelanite instead. We replaced 10%, 20%, 30%, 40%, and 50% of the sand with porcelanite to see how it would influence the concrete's thermal characteristics. Further examined the ratio of water to cement, using ratios of 0.4 and 0.5 by doing this, we wanted to see how both ratio of water to cement, and amount of porcelanite affected the thermal properties of the concrete. It was found that porcelanite makes self-compacting concrete harder to work with, and less able to conduct and spread heat. However, it does make the concrete hold more heat. When nano silica was used, it reduced workability of SCC. However, its effect on thermal properties was not of much significance. [ABSTRACT FROM AUTHOR]

Recent advances have shown the beneficial impact of adding nanoparticles to thermal oil. Diamond and boron nitride nanoparticles have superior thermal conductivity and excellent thermal and optical properties. In the current study, thermal conductivity, specific heat, and rheological behavior of diamond and boron nitride-based hybrid nanofluids in thermal oil are experimentally investigated for 0%, 0.2%, 0.4%, and 0.6% weight concentrations and a wide range of temperatures. The proportion between diamond and boron nitride utilized in the study is 1:1. A two-step method is applied to prepare stable hybrid nanofluids. The obtained data indicate that the hybrid nanofluids' thermal conductivity and specific heat enhance with increasing temperature and weight concentration. Almost 37.4% and 48.1% enhancement is observed in the thermal conductivity and specific heat, respectively, at 65 °C and 0.6% weight concentration. Thermal oil-based hybrid nanofluids display Newtonian behavior at low shear rates and an inverse relationship with temperature. Shear-thinning non-Newtonian behavior is observed at high shear rates and temperatures. A maximum increase in viscosity up to 22.0% is observed at 65 °C and 0.6% wt. concentration. The relative change indicates that all investigated properties have a significant impact, where the increasing trend of thermal conductivity and specific heat with increasing temperature and weight concentration of thermal oil-based hybrid nanofluids make them suitable for high-temperature heat transfer applications. [ABSTRACT FROM AUTHOR]

The application of nanotechnology in the field of Buildings and concrete Build is one of the main goals of this article because of the technology's role in enhances the properties of concrete and increasing the efficiency of building materials, as well as in preserving natural resources, reducing environmental pollutants, and increasing the attention that nanotechnology is currently receiving in various fields of science and engineering applications. By partially replacing cement with silica nanoparticles, the current research is focused on investigate the impact of silica nanoparticles (SiO2) on the concrete thermic properties, including specific heat capacity (SHC), thermic conductivity, and thermic diffusivity, in order to produce lightweight concrete with good thermal insulation capabilities. In order to replace a portion of the concrete's weight, nano-silica (NS) was added in percentages of 1%, 2%, and 3%. The results showed that the mixtures including nano-silica had lower thermic conductivity coefficient values, ranging from 0.5 to 0.92 W/m.°C. This indicates that the thermic insulation capacity of nano-concrete increased by 41.8 percent, 53.15 percent, and 65.57 percent, respectively. Furthermore, based on the data, Thermal conductivity coefficient's can be lowest value at a ratio of (3%). As a result, replacing concrete beyond this proportion will result in a reduction in its various qualities. Furthermore, a reduction in the specific thermic ability values was noted in contrast to traditional concrete. [ABSTRACT FROM AUTHOR]

The most important thermal and rheological properties of water-based CaCO3/SiO2 dual hybrid nanofluid (DHNF) at overall volumetric concentrations of the nanoparticles from 0.1 to 0.5 and different volume fractions at temperatures of 15–60 °C have been studied. Prepared DHNFs consisted using SDS and ultrasonic homogenizer. Stability analysis of the DHNFs performed by changing ultrasonication time and power. The optimum consistency conditions and volume fractions of the nanoparticles determined for the prepared DHNFs. Specific heat capacity, thermal conductivity and resistivity, usual viscosity and density of the DHNFs studied, experimentally, compared with preexisting models, and finally, theoretical models with 99% precisions suggested. Maximum augmentation in thermal conductivity attained to 21.8% for 80:20 corresponding volume ratio and 0.5 vol% total concentration. At these conditions, maximum reduction in heat capacity occurred as 1.08%, and the greatest reduction in thermal resistivity got about 22.2% at 60 °C. Usual viscosity and density increased as 36.9 and 1.2%, respectively. [ABSTRACT FROM AUTHOR]

Molten salt-based nanofluid is a thermal storage and heat transfer medium for concentrated solar thermal power plants formed by adding nanoparticles to molten salt, which can enhance the thermal performance of molten salt. However, the nanoparticles tend to aggregate in nanofluids, causing changes in thermal properties. In this work, molecular dynamics simulations were used to study the effect of morphological characteristics of aggregates on the thermal conductivity and specific heat capacity of molten salt-based nanofluids. The results show that the aggregated nanoparticles cause a greater increase in thermal conductivity and specific heat capacity than dispersed nanoparticles. Additionally, the increase in fractal dimension leads to thermal conductivity reduction, while there is no clear correlation between the fractal dimension and specific heat capacity. New insights into the thermal properties of aggregated nanofluids are provided by analyzing the contribution of material components, heat flux fluctuation modes, and energy compositions. It is found that the thermal conductivity of aggregated nanofluids is mainly dominated by the base liquid and collision term. However, the specific heat is not related to the variation in the contribution of different energy compositions. Moreover, compared to the dispersed nanofluid, the increased specific heat capacity of aggregated nanofluids is attributed to the thicker semi-solid layer. This study provides guidance for the design and control of the thermal properties of molten salt-based nanofluids. [ABSTRACT FROM AUTHOR]

The thermodynamic and kinetic simulations based on the re-assessment of the thermodynamic and kinetic database of the Ni-Ti-Cu system were employed to predict the phenomena of mechanical alloying, spark plasma sintering and thermal properties of the intriguing Ni-Ti-Cu system. Thermodynamic calculations are presented for the stable and unstable phases of NiTiCu materials and support a correlation with the evolving microstructure during the technological process. Also, the thermal conductivity, the thermal diffusivity and the specific heat of spark plasma sintered and aged Cu-alloyed NiTi-based shape memory alloys (NiTiCu) with two compositions, Ni45Ti50Cu5 and Ni40Ti50Cu10, are evaluated and the influence of mechanical alloying and precipitates on thermal properties is discussed. Measurements of these thermal properties were carried out from 25 °C up to 175 °C using the laser flash method, as well as differential scanning calorimetry. The thermal hysteresis of the 20 mm diameter samples was between 8.8 and 24.5 °C. The observed T0 temperatures from DSC experimental transformation features are in reasonable accordance with the thermodynamic predictions. The determined k values are between 20.04 and 26.87 W/m K and in agreement with the literature results. Moreover, this paper can provide some suggestions for the preparation of NiTiCu shape memory alloys and their applications. [ABSTRACT FROM AUTHOR]

The current paper has the objective of exploring the thermophysical properties (TPPs) of single walled carbon nanotube (SWCNT) nanofluids (NFs) for heat transfer applications. The effect of dispersing the nanotubes in conventional heat transfer fluids (HTFs) has been investigated. Carbon nanotubes (CNTs) have exceptionally high thermal conductivities. Using the effective medium theory, density, specific heat, thermal conductivity, and viscosity has been evaluated as functions of volume fractions. The base fluids considered in this work are water, ethylene glycol, engine oil, and kerosene oil as these are the commonly used HTFs for industrial applications. Theoretical predictions from this study show an increase in density, thermal conductivity, and viscosity with volume fraction while there is a decrease in specific heat with volume fraction. The effect of the aspect ratio (AR) of CNTs on the thermal conductivity of NF is also investigated. For low volume fractions of SWCNT, the thermal conductivity has been found to increase with AR. Further, this study has been extended for a real‐world application of heat transfer using SWCNT. In this paper, a numerical investigation of heat transfer in a square enclosure with differentially heated vertical walls, filled with SWCNT‐water NF under natural convection is carried out. Due to low concentrations of SWCNT in water, single phase flow is assumed. Velocity and temperature distributions are obtained as solutions to the energy and Navier–Stoke's equations. A comparison of the temperature and velocity profile has been represented by simulating the system over a range of Rayleigh numbers. [ABSTRACT FROM AUTHOR]

Heat transport in two dimensions is fundamentally different from that in three dimensions. As a consequence, the thermal properties of 2D materials are of great interest, from both scientific and application points of view. However, few techniques are available for the accurate determination of these properties in ultrathin suspended membranes. Here, we present an optomechanical methodology for extracting the thermal expansion coefficient, specific heat, and thermal conductivity of ultrathin membranes made of 2H-TaS2, FePS3, polycrystalline silicon, MoS2, and WSe2. The obtained thermal properties are in good agreement with the values reported in the literature for the same materials. Our work provides an optomechanical method for determining the thermal properties of ultrathin suspended membranes, which are difficult to measure otherwise. It provides a route toward improving our understanding of heat transport in the 2D limit and facilitates engineering of 2D structures with a dedicated thermal performance. [ABSTRACT FROM AUTHOR]

Since the fusing process in electrophotography has a significant impact not only on printing quality but also on machine internal temperature and toner blocking on outlet tray, accurate paper temperature prediction for various types of papers is essential, especially in the production printing. To develop the thermophysical model of fusing process to predict the paper temperature after the fusing process, thermal properties such as thermal conductivity, specific heat, and thermal contact resistance of several types of papers are necessary. However, paper is composed of complex fiber, surface coating, filler, and moisture, making it difficult to measure thermophysical properties of paper accurately. This work developed a machine learning (ML) model that can predict the thermophysical properties of paper based on a conventionally used 1D thermal network model of the fusing process and experiment results. The thermophysical properties of each paper obtained by ML and the thermophysical properties obtained by the conventional method were input to the thermal network model to predict the paper temperature after the fusing process and compared with the measured paper temperatures of the experiment. The results showed that the paper temperature was predicted with higher accuracy by using thermophysical properties obtained by ML than that by the conventional method. Although the method for predicting paper temperature by using only ML had been proposed, it had the disadvantage of requiring a large number of training experiments. In contrast, this method trained under the conditions of one fusing temperature and two printing speeds, and was able to predict under five fusing temperatures and four printing speeds. [ABSTRACT FROM AUTHOR]

This work investigates the physical–thermal properties of nanofluids made from graphene powder, propylene glycol, and water. Propylene glycol and water were mixed in the following ratios to make nanofluids: 100:0, 75:25, and 50:50. Graphene was added at 0.25 and 0.5% of the mixture's volume to the three base fluids. Nanofluids' viscosity, density, thermal conductivity, and specific heat are studied. After mixing with graphene nanopowder, critical fluids increased in density and thermal conductivity. Essential fluids showed these advantages. When the temperature was elevated, viscosity and specific heat decreased. Despite constant temperatures, this was the case. Increasing graphene concentration increases thermal conductivity by 10–16%. The viscosity of nanofluids with graphene nanopowder is less affected by temperature. As temperature rises, nanofluid density falls. Temperature and density are inversely related; thus, this makes sense. Adding graphene to propylene glycol at different concentrations increased its specific heat by 8–14%, depending on the concentration. [ABSTRACT FROM AUTHOR]

5at.% Yb:Lu2O3 transparent ceramics were fabricated successfully by vacuum sintering along with hot isostatic pressing posttreatment from the nanopowders. The influences of calcination temperature on morphology and microstructures of powders and ceramics were studied systematically. The optimal ceramic sample from the nanopowder calcined at 1050°C shows uniform and dense microstructure with the in‐line transmittance of 81.5% at 1100 nm. The results of the thermal measurements, that is, thermal conductivity and specific heat, were related to the changes occurring in the microstructure of the ceramics studied. It was shown on this basis that appropriate control of the technological process of sintering ceramics makes it possible to obtain laser ceramics with very good thermal properties as well as maintaining their high optical quality. Concerning the laser performance, the highest‐optical quality 5at.% Yb:Lu2O3 sample was pumped in quasi‐continuous wave conditions measuring a maximum output power of 2.59 W with a corresponding slope efficiency of 32.4%. [ABSTRACT FROM AUTHOR]

Aerogels, due to their unique features like lightweight, ultra-low thermal conductivity, and design variations, have gotten a lot of interest in thermal insulation, photocatalysis, and protective areas. Besides their superior thermal properties, aerogel thermal insulation and photocatalyst materials also possess many inherent flaws, such as handling issues, high manufacturing costs, and low strength as well as toughness. The most persuasive and successful ways to improve photocatalytic and thermal insulating qualities while lowering costs are composition optimization and microstructure reconstruction. Their high surface area and porosity make them ideal for enhancing the efficiency and capacity of these devices. Research may lead to more efficient and longer-lasting energy storage solutions. This review describes the characteristics, microstructural reconstruction, design variation, and properties of all aerogel fabrication techniques and provides a comprehensive overview of scientific achievements linked to them. The effectiveness of raw material compositions, properties, and mechanical parameters are also discussed. The major goal of this review is to highlight the aerogel-based materials and design variations and to explore the most potential development trends for photocatalysis and thermal applications. The industrial as well as technical applications of silica aerogels are also highlighted. This review highlights futuristic applications of aerogel-based textile materials to alleviate the CO2 burden on our atmosphere, either by providing next-level thermal insulation or by employing them in CO2 mitigating technologies such as CO2 capture. [ABSTRACT FROM AUTHOR]

It is well known that thermal conductivity measurement is a challenging task, due to the weaknesses of the traditional methods, such as the high cost, complex data analysis, and limitations of sample size. Nowadays, the requirement of quality of life and tightening energy efficiency regulations of buildings promote the demand for new construction materials. However, limited by the size and inhomogeneous structure, the thermal conductivity measurement of wall samples becomes a demanding topic. Additionally, we find the thermal parameter values of the samples measured in the laboratory are different from those obtained by theoretical computation. In this paper, a novel signal-transmissive wall is designed to provide the problem solving of signal connectivity in 5G. We further propose a new thermal conductivity predictor based on the Harmony Search (HS) algorithm to estimate the thermal properties of laboratory-made wall samples. The advantages of our approach over the conventional methods are simplicity and robustness, which can be generalized to a wide range of solid samples in the laboratory measurement. [ABSTRACT FROM AUTHOR]

Temperature-dependent thermal and spectroscopic properties of Nd:YVO4 crystal at temperatures ranging from 77 to 300 K are presented. Thermal properties including specific heat, thermal expansion coefficient, and thermal conductivity are investigated. The spectroscopic parameters, such as absorption, fluorescence, lifetime are also studied. The calculated absorption and emission cross-sections together with relevant thermal properties provide important information for designing cryogenically cooled near infrared laser. Furthermore, we experimentally explore continuous wave (CW) laser performances under various cryogenic temperatures. A maximum output power of 2.13 W is obtained at an incident pump power of 3.7 W at 150 K, corresponding to an optical-to-optical conversion efficiency of 57.6%. [ABSTRACT FROM AUTHOR]

Engineering properties of wild banana seeds at different moisture content (8.66%, 12%, 16%, 20%, and 24% db) were investigated. Physical dimensions, seed surface area (SA), seed volume (SV), and thousand seed mass (M1000) increased linearly with increase inmoisture content. While porosity decreased linearly from 42.33% to 38.89%, bulk density (ρb) and true density (ρt) increased from 513.59 to 564.72 and 890.56–924.09 kg m−3, respectively. The angle of repose increased linearly from 29.84 to 36.48 with moisture content. The increased moisture content also caused an increase in static coefficient of friction for surfaces made of stainless steel, glass, and plywood. The thermal conductivity (λ) and volumetric specific heat (ρcp) were found to increase linearly from.17 to.20 Wm−1 K−1, and.58 to.99 MJ m−3 K−1, and thermal diffusivity (α) decreased from.31 to.19 (×10−6 m2 s−1) with a increase in moisture content. Practical applications: The research aimed to study the engineering properties of wild banana seeds as a function of moisture content as they are necessary to design equipment for handling, aeration, storage, and processing. Moreover, it helps in predicting flow and handling behavior during processing, including hopper flow, and conveying through feeders and other handling equipment. Furthermore, thermal properties are helpful in engineering, process design and modeling the thermal behavior of food products during storage, processing, and transportation. [ABSTRACT FROM AUTHOR]

Compressed stabilized earth block is a local building material, which has incontestable ecological advantages, in addition to a good and approved mechanical resistance. The purpose of this article is to provide the missing information in the literature regarding the dependence on moisture of the thermal properties of CSEB, and to analyze the hydric behavior of this material. Measurements show that an effective thermal conductivity and diffusivity increases with increasing moisture content. A linear relationship, between thermal conductivity and moisture content is obtained. Theoretical analysis allows also to deduce specific heat and thermal effusivity. Thermal inertia is quantified by phase shift and thermal damping. The effect of moisture on all the thermal properties is established. Experimental characterization of CSEB behavior during capillary water absorption and convective drying is investigated as well. Experiments are performed under natural and forced convection on several blocks. CSEB presents interesting thermal characteristics. Results show that the moisture effect is very important and cannot be neglected during the calculation of the envelope thermal behavior or the building's energy consumption. [ABSTRACT FROM AUTHOR]

InI single crystals are a promising room temperature detector material for X-rays and γ-rays. To improve crystal growth of the material by simulations, knowledge of thermophysical properties is essential, and since InI is orthorhombic, the anisotropy has to be taken into account. The temperature-dependent thermophysical properties have been measured for InI, including the anisotropic thermal expansion, specific heat, and the thermal diffusivity in the b direction. The anisotropic thermal expansion coefficients, determined by X-ray diffraction, were α11 = 1.03 × 10–5 K−1, α22 = 3.77 × 10–5 K−1, and α33 = 6.26 × 10–5 K−1. The specific heat, measured by DSC, was 0.226 J·g−1·K−1 at 335 K, with a temperature dependence of 9.582 × 10–5 J·g−1·K−2. In the course of the X-ray diffraction and DSC measurements, it could also be shown that supposed phase changes, reported in older literature, are actually not phase changes but oxidation effects. The thermal diffusivity in the b direction, measured by the Xenon Flash method, was 0.288 × 10–6 m2·s−1 at RT, decreasing to 0.253 × 10–6 m2·s−1 at 450 K. In addition, the volume increase upon melting and the thermal expansion of the melt have been determined. [ABSTRACT FROM AUTHOR]

The absorption of heat by rocks is accompanied by an increase in the kinetic energy of molecules and atoms and is recorded by a change in rock temperature. The thermal properties of rocks characterize the ability to transfer and absorb heat and change their size when the temperature rises. The main thermal properties of rocks are thermal conductivity, heat capacity, linear thermal expansion, and thermal volumetric expansion. In this paper, the influence of temperature effects on the thermal properties of reservoirs – the coefficient of temperature conductivity, specific heat capacity, and thermal conductivity is studied using the samples of oilsaturated reservoirs from the good number 19Bp of the Upper Uplift of Sotnikovsky deposit. The dependence of the thermal properties of the core material on temperature was revealed using a number of laboratory experiments. The results of these studies contribute to improving the reliability of data on the relationship of thermal properties with other physical properties of oilsaturated reservoirs and can be used to improve the efficiency of the development of fields of superviscous oil. [ABSTRACT FROM AUTHOR]

Thermal properties of pulverized coal govern the heat transfer and greatly influence the coal dust explosion and spontaneous combustion processes. This study measures the thermal properties of five coal samples at six distinct particle sizes using an advanced thermal property analyzer. The thermo-physical properties of coal dust positively correlated with the particle size. Thermal conductivity, diffusivity, and specific heat capacity increased with the ash percentage, bulk density, and specific gravity of coal dust. In contrast, they negatively correlated with the fixed carbon and volatile content of coal. Empirical relations between the thermo-physical properties were developed. The thermal conductivity, diffusivity, and specific heat capacity of coal dusts varied in the range of 0.091–0.147 W/mK, 0.125–0.164 mm2/s, and 0.715–0.945 MJ/m3K, respectively. With increase in particle size from < 38 to 500–1000 µm, thermal conductivity, thermal diffusivity, and specific heat capacity increased in the range of 25.60–32.89%, 9.76–22.11%, and 9.57–20.80%, respectively, for different coal samples. [ABSTRACT FROM AUTHOR]

A Nd3+-doped Ca3Nb(Al0.5Ga0.5)3Si2O14 (Nd:CNAGS) crystal with dimensions 50 × 80 × 16 mm³ was grown for the first time using the Czochralski (Cz) method as a potential material for ultrafast laser application and elastic optical modulators. The thermal expansion coefficients in different directions show a small difference, which means that the crystal expands more uniformly and could reduce the internal stress concentration when the temperature changes. The specific heat of Nd:CNAGS in the temperature range of 25-300 °C was in the range of 0.632-0.988 J g-1 K-1. The thermal conductivity of the crystal is anisotropic, and the thermal conductivity in the z direction increases with the increase of temperature and is obviously greater than that in the x direction. The optical properties of the crystal, including absorption, transmission, and fluorescence spectra, have been systematically analyzed; the strongest absorption peak with a full width at half-maximum (FWHM) of 19 nm is centered at 805 nm wavelength, and the broad emission band with a peak at 1066 nm has an FWHM of 16 nm. The experimental line strength, the calculated spectral line intensities, the spontaneous radiation probability, the fluorescence branching ratio, and the radiation lifetime are obtained using the Judd-Ofelt (J-O) theory. A 1.06 μm continuous-wave (CW) laser output was realized using the Nd:CNAGS crystal. The maximum output power at 1.06 μm wavelength is 1.54 W at an incident pump power of 12.87 W under an output coupler of 5% along the x-axis direction, corresponding to an optical-to-optical conversion efficiency of 11.97% and a slope efficiency η of 12.28%. [ABSTRACT FROM AUTHOR]

In this work, the results of investigations of polyurethane materials were presented. Innovative materials based on polyurethane-polyisocyanurate (PUR/PIR) foam were obtained. Different types of additives (flame retardants, aerogels – additives that decrease thermal conductivity) are used in the composition of PUR/PIR foam. Foams are a type of composite composed of two phases: continuous (polyurethane polymers) and dispersed (composed of gases). All samples have been tested for thermal parameters: thermal conductivity, specific heat, and thermal diffusivity. Then they have been compared with each other and with a reference sample (RS) without additives. Based on the research, it was shown that innovative insulation materials were characterized by thermal conductivity λ in the range of 0.0254–0.0294 W/(m · K). The thermal properties of foams depending on the type and chemical composition of the material. Depending on the used substrates, their molar ratio, type, synthesis conditions, modifying agents and catalysts, a different polyurethane material is obtained. [ABSTRACT FROM AUTHOR]

The study of thermal properties such as conductivity and specific heat of biomaterials is very important as most biological processes, in which biological tissues, cells, and molecules are involved are dependent on body temperature. The main source of body heat is the chemical metabolism of food. Various mechanisms are being adopted by different types of animals to maintain body temperature, such as reducing blood flow through the capillaries nearest the skin surface, body hair can be fluffed up to increase insulation, heat production by shivering, etc. The hard and soft tissues, such as the flesh and bone of animals, play a very important role in keeping the required body temperature. The thermal conductivity and specific heat of the femur, rib, and scapula of two different environment animal ox, the wetland and camel desert dry land are investigated in normal and decalcified conditions. Modified Lee’s apparatus has been used to determine the thermal conductivity, while Renault’s apparatus which is based on the principle of the method of mixtures has been employed for determining the specific heat of samples that were pelletized. A difference in conductivities and specific heat of various bones in both animals was observed due to varied calcium phosphate. The decalcified bone samples of ox and camel show higher thermal conductivity compared to normal bones, while a decrease in specific heat was observed in decalcified bones. The specific heat is affected by the variations in the molecular structure due to changes in temperature. The paper suggests that these techniques are simple, elegant, and inexpensive besides being accurate. [ABSTRACT FROM AUTHOR]

Monolithic Al 2 O 3 and Al 2 O 3 -graphene-SiC hybrid composites were prepared by spark plasma sintering (SPS) under vacuum atmosphere. The results show that the hybrid composites were almost completely dense (>97%). SiC content has a significant effect on the microstructure of the composites. With the increase of SiC content, the average grain size of alumina decreased gradually. The addition of SiC to alumina changed fracture mode from inter-granular fracture to mixed fracture mode of inter-granular fracture and trans -granular fracture. The Al 2 O 3 -0.4 wt%graphene-5 wt% SiC hybrid composite has the highest bending strength and hardness, which were 57% and 19.22% higher than those of the monolithic alumina, respectively. The room temperature (RT) thermal conductivity of the monolithic Al 2 O 3 (25.5 W/m·K) was the highest. The thermal conductivity and thermal diffusivity coefficient of the composites decreased with the increase in temperature, while the specific heat of monolithic alumina and composites increased with the increase in temperature and additives. These properties were related to the microstructure of materials and the possible transport mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Thermal transport properties of graphene nanoribbons (GNRs) are investigated using phonon transport studies. Ribbons of varying widths are considered to investigate the transition of key thermal properties with width. The lattice structure of the ribbons is fully resolved, and phonon transport is modeled by accounting for all three-phonon scattering processes using a solution of the linearized Boltzmann transport equation. A 3× reduction in intrinsic thermal conductivity is observed compared to bulk graphene arising from increased strength of three-phonon scattering due to the additional nondegenerate phonon modes that appear due to the finite edges of confined nanoribbons. Strong dependence of thermal conductivity on ribbon width is also observed. The underlying mechanisms for thermal conductivity reduction and width dependence are presented by analyzing frequency- and polarization-resolved phonon transport. The additional scattering pathways present in 1D GNRs lead to a significant reduction in the thermal conductivity of otherwise highly conducting flexural phonons in bulk graphene. In contrast, confinement-induced changes to the density of states, specific heat or group velocity, and the subsequent impact on lattice thermal conductivity are found to be relatively small. [ABSTRACT FROM AUTHOR]

Photothermal deflection (PTD) has been frequently utilized to measure the thermal properties of thin solid films on a substrate. In the models commonly used to interpret PTD data, the substrate is assumed to be an ideal thermal insulator. This assumption poses important restrictions on the reliability of these thermal measurements and limits the possibility to use PTD for also measuring the specific heat of the samples. Simultaneous knowledge of specific heat and thermal diffusivity is necessary to determine the thermal conductivity of thin solid films. In this work, we calculated the phase and amplitude of the PTD signal at the two opposites sides (film-side and substrate-side) of a thin-film substrate system. We find that, on both sides, the phases of the PTD signal primarily depend on the thermal diffusivity of the thin film, while the amplitudes primarily depend on the specific heat. By using the phases and amplitudes at the two sides, we show that the accuracy of thermal conductivity measurements by PTD can be dramatically improved. We validate our theoretical model by measuring, in a scanning PTD apparatus, the thermal properties of gold thin films, which are in excellent agreement with, and improve on, existing data from the literature. [ABSTRACT FROM AUTHOR]

The thermal properties of methane hydrate (MH)‐bearing sediments are necessary for developing gas production technologies (e.g., gas production rate prediction). The direct thermal property measurement of a general MH reservoir is difficult because it demands an advanced coring and measuring technology. Therefore, a good thermal property value estimation model for a system containing sediment grains, water, MH, and gas is necessary. In 2018, the pressure core samples were recovered from the AT‐CW1 and AT‐CW2 wells in Nankai Trough of Japan. Using a single‐sided transient plane source method, we measure herein the thermal property values of those core samples and estimate their thermal conductivity by improving existing models. The measured thermal conductivity (λ), specific heat (ρCp), and thermal diffusivity (α) of the MH‐bearing sediments before and after MH dissociation are obtained. The de Vries model agrees well with the measured thermal conductivity values before and after the MH dissociation. For the random distribution (geometric mean) model, the difference between the estimation values and the data after the MH dissociation increases as the gas saturation Sg′ increases. In the worst case, the distribution model shows an 87.6% error, while the de Vries model yields 5.2% of the same. We propose and use an estimation method of the thermal property values in an MH reservoir, which requires classical thermophysical models and well log data. The in‐situ thermal property values can be estimated when the log data are highly accurate. Plain Language Summary: In recent years, several countries and organizations have conducted research projects on gas production from methane hydrate (MH) sediments under the ocean floor. One of the key technologies of these projects is the gas production simulator that requires physical parameter determination and models for accurate prediction. The required physical parameters remain scarce because MH dissociates under atmospheric pressure and normal temperature conditions. In this study, we measure the thermal property values of MH‐bearing sediment cores recovered from the Nankai Trough area in Japan. Various prospective models for estimating the thermal conductivity of MH‐bearing sediments have been developed, but a universally applicable unified model has not yet been created. We test classical estimation models for thermal conductivity and show that the de Vries model agrees well with the measured values of MH‐bearing sediment before and after MH dissociation. The random distribution model agrees well before dissociation, but does not agree after it. In the worst case, the random distribution model shows an 87.6% error. We propose and test an estimation method of the thermal property values obtained from an MH reservoir. The results will help in improving gas production technologies for MH deposit recovery. Key Points: The thermal property values of 29 core samples retrieved from a gas hydrate reservoir were measuredThe thermal property values before and after methane hydrate (MH) dissociation can be estimated using a classical modelWe proposed and used an estimation method for thermal property values in a MH reservoir [ABSTRACT FROM AUTHOR]

The 1045 steel is extensively heat treated because its mechanical properties can be easily improved by thermal processes. Reliable knowledge of the relationship between microscopic structure and thermal properties is essential for the thermal design of parts and tools. This paper reports on coupling microstructural aspects with the effects of tempering temperature on the temperature-dependent thermal properties of 1045 steel. Thermal conductivity (k) and specific heat (cp) were simultaneously estimated using inverse heat conduction analysis. The thermal characterization technique handled a simple and low-cost experimental setup, based on transient one-dimensional heat transfer on samples subjected to different heat-treatment conditions. The results, which were discussed in connection with the resulting microstructures, demonstrated that all quenching and tempering (Q&T) conditions led to lower values of both thermal properties throughout the temperature domain. The tempering temperature was found to impact k more substantially. The robustness of the results was ascertained by recovering the applied heat flux based on linear regression equations for k and cp and temperature measurements. Accuracy analysis indicated that the inverse approach provides estimates with an uncertainty close to 4%. [ABSTRACT FROM AUTHOR]

A GaNbO4 single crystal (ϕ = 24 mm) was successfully grown for the first time by the Czochralski (CZ) method, and the thermal and optical properties were systematically studied. The structure parameters were calculated and belong to the monoclinic C2/m space group. The half-peak width of the rocking curve is 26.63 arcsec, indicating that the crystal is of relatively high quality. The specific heat, thermal diffusion coefficient, and thermal conductivity were measured systematically. The thermal expansion coefficients of the GaNbO4 crystal in different directions were obtained and it is proved that the GaNbO4 crystal has negative thermal expansion along the crystallographic b-axis. The orientation relationship between the thermal expansion ellipsoid axis and the crystallographic axis is determined. The UV-vis diffuse reflectance spectra and the transmittance spectra of the GaNbO4 crystal were measured, and the band gap and the orientation relationship between the optical axis and crystallographic axis were confirmed. The chemical composition was analyzed using X-ray photoelectron spectroscopy (XPS). [ABSTRACT FROM AUTHOR]

Ionanofluids (INF) are combinations of ionic liquid (IL) and nanoparticles (NP) with superior thermophysical properties. In the present study, measurement of thermophysical profile of IL, 1-ethyl-3-methylimidazolium chloride ([EMiM]Cl) in which Al2O3 NPs are dispersed were undertaken in the temperature range of 303.15–333.15 K. INFs were prepared by dispersing Al2O3 NPs in different mass concentrations of 0.5, 1.0, 2.5, 5.0, and 10%. The results showed that specific heat and thermal conductivity increase with both concentration and temperature. In contrast, the viscosity and density increase with concentration and decrease with temperature rise. The maximum INF thermal conductivity and viscosity enhancements were 21.9% and 77.6% for a mass concentration of 10% compared to IL at 333.15 K and 303.15 K. Electrical conductivity decreases with NP addition and increases linearly with an increment in temperature. Based on the measured results, a correlation for the specific heat, thermal conductivity, and viscosity of INF was proposed. Further, the heat transfer performance of studied INF is theoretically estimated based on the experimental thermophysical properties. Finally, for high-temperature applications methylimidazolium chloride-based INFs can be used as an efficient candidate as primary heat transfer fluid. [ABSTRACT FROM AUTHOR]

The main aim of the current article is to describe an uni-dimensional moving boundary problem with conduction and convection effect when thermal conductivity and specific heat varying linearly with temperature and time. The Mathematical model has nonlinearity due to presence of variable thermal conductivity and specific heat. A Legendre wavelet residual approach is introduced to get the solution of the problem with high accuracy. The surface heat flux is taken as an exponent function of time while latent heat is presented as an exponent function of position. Galerkin technique is used to obtain the numerical solution in case of constant physical properties while collocation technique is used for variable thermal physical properties. When it is considered that thermal physical properties are constant then obtained numerical solution was compared with exact solution and found in good acceptance. The effect of convection and variable thermal conductivity with time and temperature on the location of the moving layer thickness is analyzed. Further the effect of Peclet number and other physical parameters on the location of moving layer thickness are discussed in detail. [ABSTRACT FROM AUTHOR]

Due to a lack of geotechnical and geothermal studies on Jordanian limestone, this paper aims to provide the thermal properties, including thermal conductivity, thermal diffusivity, and specific heat, using the Hot Disk Transient Plane Source (TPS) 2200 method. It also aims to provide a set of mathematical models through which the thermal properties can be indirectly predicted from the rocks' physical and engineering properties. One hundred cylindrical rock specimens with a height of 20 cm and a diameter of 10 cm were extracted and prepared. The results showed that the thermal conductivity values ranged between (1.931–3.468) (W/(m × k)), thermal diffusivity (1.032–1.81) (mm2/s), and specific heat (1.57–2.563) ((MJ)/(m3 × K)). The results also suggest a direct relationship between conductivity and diffusivity and an inverse relationship between conductivity and specific heat. On the other hand, the results indicate the direct relationship between the conductivity and diffusivity, and the inverse relationship between the specific heat and density, hardness, sound velocity, and rock strength; the opposite happens when the rock's porosity is considered. Simple regression, multivariate regression, and the backpropagation–artificial neural network (BP–ANN) approach were utilized to predict the thermal properties of limestone. Results indicated that the ANN model provided superior prediction performance compared to other models. [ABSTRACT FROM AUTHOR]

The temperature dependence of thermal conductivity and specific heat for detonated nanodiamond ceramics is investigated on specially designed experimental setups, implementing the uniaxial stationary heat flow method and the thermal relaxation method, respectively. Additionally, complementary studies with a commercial setup (Physical Property Measurement System from Quantum Design operating either in Thermal Transport or Heat Capacity Option) were performed. Two types of samples are under consideration. Both ceramics were sintered at high pressures (6–7 GPa) for 11–25 s but at different sintering temperatures, namely 1000 °C and 1600 °C. The effect of changing the sintering conditions on thermal transport is examined. In thermal conductivity κ(T), it provides an improvement up to a factor of 3 of heat flow at room temperature. The temperature dependence of κ(T) exhibits a typical polycrystalline character due to hindered thermal transport stemming from the microstructure of ceramic material but with values around 1–2 W/mK. At the lowest temperatures, the thermal conductivity is very low and increases only slightly faster than linear with temperature, proving the significant contribution of the scattering due to multiple grain boundaries. The specific heat data did not show a substantial difference between detonated nanodiamond ceramics obtained at different temperatures unlike for κ(T) results. For both samples, an unexpected upturn at the lowest temperatures is observed—most likely reminiscent of a low-T Schottky anomaly. A linear contribution to the specific heat is also present, with a value one order of magnitude higher than in canonical glasses. The determined Debye temperature is 482 (±6) K. The results are supported by phonon mean free path calculations. [ABSTRACT FROM AUTHOR]

The use of insulation materials is crucial for minimizing thermal losses in various industries like automotive, building, solar, and aerospace. Plexiglass and Expanded Polystyrene (EPS) foam are popular choices due to their effective temperature regulation, lightweight nature, and cost-effectiveness. Accurate measurement of their thermal properties is vital for achieving conservation goals. While the parallel hot wire technique provides valuable insights, accurately determining heat source strength (H W) poses a challenge, impacting measurement accuracy. To address this, the modified Conjugate Gradient Method (CGM) is employed for simultaneous estimation of thermal conductivity (λ), specific heat (c) and H W of Plexiglass and EPS foam. The direct problem result has been validated with published experimental work that shows deviations less than 2 %. The study investigates the impact of sensor positioning relative to the hot-wire (r m) and introduces artificial Gaussian error with standard deviations (θ) of 0.01 °C, 0.02 °C and 0.1 °C. At θ = 0.1 °C the percentage relative errors in the estimation of λ , c and H W with r m = 5 mm for Plexiglass are 5 %, 1.442 %, and 4.651 % respectively. For EPS foam the corresponding errors are 2.44 %, 1.26 %, and 1.74 %. The modified CGM emerges as a reliable algorithm for the measurement of thermal properties of insulation materials. • Modified CGM for estimating thermal properties of energy conservation materials. • Simultaneous estimation: heat source strength, thermal conductivity and specific heat. • The method is validated with less than 2 % deviation from published experimental work. • Evaluates sensor positioning and artificial Gaussian error impacts on method accuracy. [ABSTRACT FROM AUTHOR]

The heat transfer of the mold during the casting process has been calculated by considering the mold as a uniform isotropic material. Since the mold was not a uniform isotropic material, the calculation was performed with approximate values, and in particular, estimated values were used when considering compaction and binder addition amount. In this study, calculation of the thermal properties of the sand mold was developed. An algorithm for calculating thermal conductivity and specific heat based on a thermal resistance model in the case of mono-dispersed was developed and applied to sand molds with various size distributions. The thermal properties of sand were calculated for artificial sand, and relatively close values were obtained compared to the experimental values. [ABSTRACT FROM AUTHOR]

3D printing in the construction sector is a promising, sustainable approach with the potential to build energy-efficient buildings. However, there is a lack of studies on the thermal properties of 3D-printed structures, which are fundamental to their energy efficiency. This study investigates the impact of printing parameters on thermal conductivity and defect development in 3D-printed concrete structures. Heat flow meter, scanning electron microscope and infrared imaging techniques were employed to assess the thermal properties and microstructure of 3D-printed samples. The results demonstrate that printing parameters significantly influence the porosity, void formation, and microstructural characteristics of 3D-printed concrete, ultimately affecting thermal properties. An increase in extrusion rate leads to higher thermal conductivity, whereas an increase in speed and standoff distance reduces thermal conductivity. Excessive spacing between printed lines can induce voids and gaps, contributing to lower thermal conductivity, while minimal spacing can promote higher porosity and larger pores. Infrared imaging revealed nonuniform thermal distribution in 3D-printed structures caused by the layered structure and voids in interlayer gaps. This study provides valuable insights for designing and constructing energy-efficient 3D-printed buildings, contributing to the development of sustainable building practices and the advancement of additive manufacturing in construction. [Display omitted] • The printing process significantly affects the thermal properties of 3D-printed concrete structures. • Increase in printing speed, nozzle standoff distance decreases thermal conductivity. • An increase in extrusion rate increases thermal conductivity. • Thermal defects can be caused by the printing process. • 3D printed structures have nonuniform heat transfer with specific pattern. [ABSTRACT FROM AUTHOR]

• Influence of natural convection on the experimental characterization of liquid thermal conductivity of octadecane. • Inverse method based on heat flux measurements to characterize the thermal conductivity and specific heat capacity of the PCM at liquid state. • A comparison of the Nusselt numbers estimated from combining the numerical and experimental results with the known correlations for the different experimental conditions was carried out. This paper numerically makes use of the inverse method coupled with experimenal results obtained through the fluxmetric method in the Laboratoire de Génie Civil et géo-Environnement (LGCgE) to determine the specific heat, thermal conductivity and thermal expansion coefficient of liquid n -octadecane in an enclosure accounting for natural convection present in the experimental system. The impact of ommiting the presence of natural convection for the thermophysical propertie determination is studied and shows very little effect on the specific heat value but a large error (by a factor of two in this study) on the thermal conductivity value. The correct properties identified when accounting for natural convection (ρ = 2150 J/kg‧K; k = 0.16 W/m‧K; β = 9.38 × 10−4 K−1) are consistent with the literature. Additional direct numerical work was done to determine the impact of using the different thermal conductivity values, comparing numerical to additional expermental restuls where natural convection was stronger. The thermal conductivity value played a minial role when simulating the behavior of the systems rightly accounting for natural convection. Combining the numerical and experimental resutls allowed the calculation of encolsure specific Nusselt numbers for the various experimental conditions used and a comparison to known correlations. It was determine that the Nusselt number obtained in the liquid n -octadecane were larger by 10 to 48%. [ABSTRACT FROM AUTHOR]

Chloride molten salt is a promising thermal storage material owing to its high thermal storage density, but the low thermal properties need to improved. Accordingly, a new LiCl/SiC with a SiC mass fraction of 1.0 wt% based-molten salt phase change material (PCM) was proposed to recycle the LiCl contained in the lithium-ion batteries, and the calculation and improvement method of thermal properties including thermal conductivity, specific heat capacity, melting enthalpy and viscosity etc., were developed and investigated using molecular dynamics (MD) simulations. The microstructure characteristics of LiCl/SiC molten salt were also investigated. The microscopic transformation of the structure was observed, and the results show that the self-diffusion coefficient of the system can be decreased by 4.57% with the addition of SiC nanoparticles. The thermal conductivity of the system can be increased by an average of 2.43%, and the shear viscosity can be increased by 5.4%. Besides, the melting enthalpy was decreased by 8.85%, but the specific heat capacity only strengthened by 0.8% average in the studied temperature range. It is expected be helpful for the thermal performance enhancement of recycled molten salt. • Recycling lithium chloride from waste lithium-ion batteries as PCM for thermal energy storage was proposed • Microstructure of LiCl/SiC based composite PCM with 1.0 wt% fraction of nano SiC particle was established. • MD simulations were conducted to investigated the thermal performance. [ABSTRACT FROM AUTHOR]

When heat energy is transferred to concrete through energy conversion by an electric heating system, the overall thermal performance of the early-age concrete is affected by the local high temperature of the concrete. This, in turn, affects the accuracy of the prediction and calculation of concrete deformation. Concrete thermal physical parameter models considering the mutual influence of heat and humidity were established to clarify the influence of an electric heat tracing system on the heat transfer performance of concrete at an early age, based on the concepts of equivalent age and hydration degree. Additionally, the COMSOL numerical simulation software was used for realizing the numerical solution of concrete heat transfer. The research indicates that the degree of hydration is affected by the heating provided by the electric heat tracing system. When curing for 40 h, the degree of hydration approaches 0.82 and remains unchanged, which indicates that the hydration of cement was almost complete in less than 2 days. The specific heat value of concrete in the early stage was significantly affected by electric heat tracing. This value of concrete at a high initial temperature was larger than that at a low temperature, while the specific heat of each point in the later stage tended to be the same. The thermal conductivity was significantly affected by the local electrical heating. The higher the temperature was, the lower the thermal conductivity was, which remained stable for two days under the influence of temperature. The key contribution of this research is to provide a coupling model for concrete curing. The findings from the study also provide industry practitioners with a comprehensive guide regarding the specific applications of the electric heating system in early-age concrete curing. [ABSTRACT FROM AUTHOR]

The incorporation of conductive nanoparticles into thermal energy storage media is one of the strategies to increase their thermal conductivity. This work unravels the impact of the addition of CuO nanoparticles on the thermal properties of solar salt, a high-temperature thermal energy storage material. The resultant CuO enhanced solar salt (CuOeSS) exhibited a maximum thermal conductivity improvement of 14.4 % at 40 °C when the concentration of CuO nanoparticles was 1 wt%. The prevalence of CuO nanoparticles as isolated aggregates resulted in a moderate thermal conductivity enhancement. The CuO nanoparticles greatly influenced α-KNO3 to β-KNO3 transition and reduced the expected positive influence on thermal conductivity at temperatures above 120 °C. The solid-phase specific heat was enhanced by 22.7 % for 2 wt% CuOeSS. Our results demonstrate the interplay between the different roles played by CuO nanoparticles, namely the thermal conductivity enhancement at lower temperatures and influencing the α-KNO3 to β-KNO3 transition at higher temperatures. The CuOeSS with 0.5 wt% CuO, which showed enhancement in both thermal conductivity and energy storage capacity, is a suitable energy storage material for applications in the temperature range of 100–245 °C. [ABSTRACT FROM AUTHOR]

A series of new Li 2 SiO 3 +4 wt% Al 2 O 3 -xK 2 O–B 2 O 3 –SiO 2 (x = 1–4 wt%) LTCC materials were prepared by standard traditional solid-state method and their bulk density, microstructure and crystalline phase composition were shown in detail. The sintering behavior, heat conduction and thermal expansion of the samples were all thoroughly studied. And their microwave dielectric properties were also demonstrated. The bulk density of the samples was enhanced with the addition of 3 wt% KBS glass, and the sintering temperature was reduced from 1020 °C to 900 °C. Meanwhile, the thermal diffusivity of the samples was determined using the LFA447 laser flash apparatus and the specific heat was calculated, according to the results of thermal diffusivity and specific heat, all samples possessed high thermal conductivity ranging from 5.5 ± 0.02 W/mK to 8.6 ± 0.08 W/mK. Furthermore, the attractive flexural strength and average coefficient of thermal expansion reach to 270 MPa and 15.7 × 10−6/K (at 100 °C), respectively. The reduction of the sintering temperature is attributed to the addition of KBS glass which reduces the crystallization activation energy of the samples. Besides, increasing bulk density can substantially reduce pores in the grain boundary, which has great effects on phonon scattering, improving the thermal conductivity. [ABSTRACT FROM AUTHOR]

This article aims to improve nanofiller dispersion in epoxy resins by using an electrostatic disperser (ED), as well as reduce costs by using a combination of microfillers and nanofillers. The ED method aids in homogenized mixing of nanofillers in epoxy resin, due to its jet elongation and shearing effect on a polymer mix. In this article, two concentrations (7.5 wt% and 5 wt%) of nanosilica are used with resin, and the rheological properties of hybrid composites are tested before and after the addition of 50 wt% microsilica. It is observed that the electrostatic dispersion method aids in the network formation of nanosilica, unlike the high shear (HS) method, wherein clusters of nanosilica are formed. Hence, the ED method aids in reducing the viscosity values with the addition of microsilica, which is helpful in the product molding process. A plausible mechanism of filler dispersion is explained for ED and HS methods. The morphological analysis showed that the composites are brittle due to the high silica content, and that the silica fillers are dispersed well within the epoxy matrix. The flexural strength lies in the same range for both composites prepared using ED and HS methods. Thermal conductivity depends both on nanosilica and epoxy matrix dispersion, while heat deflection temperature, thermal diffusivity and specific heat depend on the dispersion method. [ABSTRACT FROM AUTHOR]

To estimate the thermal properties of plumbene under different temperatures, a plumbene sheet is developed by multi-scale modeling. Plumbene sheets of variable sample sizes are also investigated to obtain a broader view of thermal properties of the material for useful application in several engineering fields. Melting point, specific heat at constant volume and pressure, heat of fusion and the coefficient of linear and surface expansion within a temperature range of 318–398 K are also determined. Present applied techniques will guide experimental approaches for designing of plumbene sheets with specific thermophysical properties for targeted applications. [ABSTRACT FROM AUTHOR]

We dried the orange slices massed 100 ± 0.10 g from the initial moisture content of 6.97 ± 0.02 kg water kgDM−1 to the final moisture ones of 0.12 ± 0.01 kg water kgDM−1 using two different drying methods defined as convective drying at 50, 75, 100, and 125 °C along with microwave drying at eight output power between 90 and 1000 W. In the study, we measured the drying methods' energy consumption and observed that the microwave drying method's energy consumption was very low at high and low powers. Also, we modeled the results using twenty-one different thin-layer drying equations and obtained results closest to experimental data with the modified Henderson and Pabis equation for all powers in microwave drying and all temperatures in convective drying. We calculated both effective moisture diffusivities and activation energy using the drying data. Some thermal properties such as specific heat, thermal conductivity, thermal diffusivity, and thermal effusivity were calculated and recorded to be decreasing in all thermal properties with drying. Also, we measured the color parameters known as L, a, b, C, α°, and ΔE, browning index (BI), whitening index (WI), and vitamin C (ascorbic acid) in the study. We concluded that the most suitable drying method is microwave drying at medium powers of 350 and 500 W by considering both drying and quality parameters. [ABSTRACT FROM AUTHOR]

Energy sustainability represents an important research topic for aiding decreasing energy dependence and slowing down climate changes. In this context, solutions using thermal energy storage through rock start to emerge, due to its natural benefits, when compared to more polluting alternatives. To understand whether a rock material can be considered a good thermal energy storage material for such solutions, it is necessary to evaluate the physical, chemical and thermal properties of such materials. Therefore, it becomes essential to understand how heat propagates in the rock and how voids influence the thermal properties. To achieve these goals, hematite ore from Moncorvo, Northeastern Portugal was used, in particular, to study the effect of grain size on thermal properties for three different sized lots. Chemical and physical changes between heated and unheated lots were detected using X-ray diffraction and particle size, as well as X-ray fluorescence analysis. Regarding thermal properties, a hot wire method approach was used with seven thermocouples. Additionally, a thermal inversion model to simulate the heat exchanges was also proposed, allowing changing the properties of the constituents, to fit the theoretical and experimental temperature curve. Furthermore, the model reveals how heat propagates inside the reservoir filled with hematite ore. [ABSTRACT FROM AUTHOR]

The acoustic coupling constant D, is related to the change in elastic modulus caused by strain: HT ht Graph (16)Where HT ht and HT ht are square average and average square Grüneisen parameters, respectively. [Extracted from the article]