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In this paper, a novel power sintering technique, named fast hot-pressing sintering (FHP), which is able to achieve an ultrahigh heating rate similar to the spark plasma sintering (SPS) technique, but at a much lower cost, was applied to prepare a series of Al/Si composites with different Si volume ratios (12 vol.% to 70 vol.%) to meet the requirements of advanced packaging materials for electronic devices. In contrast to SPS, the FHP oven possesses a safe and budget-friendly current power supply, rather than a complex and expensive pulse power supply, for its heating power. The optimized sintering parameters (temperature, pressure and holding time) of FHP for preparing Al/Si composites were investigated and determined as 470 °C, 300 MPa and 5 min, respectively. In order to characterize the potential of Al/Si composites as packaging materials, thermal conductivities and coefficients of thermal expansion were studied. The thermal conductivity of the Al-40Si composite sintered by the FHP method is higher than that of the conventional SPS method (139 to 107 W m−1 K−1). With the increase in Si, the thermal conductivities and coefficients of thermal expansion on both decreases. Furthermore, the thermal conductivities obey the Agari model, whereas the coefficient of thermal expansion and Si volume ratios obey additivity. The numeric modeling would help develop required packaging materials based on the thermal performances of the substrate materials, like Si or GaAs semiconductor devices. [ABSTRACT FROM AUTHOR]

Studies on the equation of state (EOS) for solids are highly valuable in the field of condensed matter physics and geophysics. The analyses of the equation of state under high compressions for solids are already performed. In the proposed study, we have considered the four different approaches (finite strain and interionic potential) to study P-V-T relationship for amorphous glasses. The theoretically obtained results are compared with available experimental data to compare and verify the best suitable equation of state for amorphous solids like glass, which can be used in the future to find the thermodynamic parameters of bulk metallic glass, which is also an amorphous solid in total. The results obtained from Shanker EOS and higher-order Shanker EOS are found to be more consistent with the experimental results. We calculate the Grüneisen parameter and thermal conductivity for the bulk metallic glasses (window and water white glasses) under high compressions. [ABSTRACT FROM AUTHOR]

This study investigated the suitability of Ijero-Ekiti quartz as a refractory raw material for industrial furnace applications. In order to ascertain its prospective applications, the thermal behaviour, mineralogical composition and chemical composition were determined. Ijero-Ekiti quartz was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric and Differential Thermal analysis (TGA and DTA). Its thermal conductivity with specific heat coefficient was determined. The outcome revealed that the quartz sample has a high purity of 94.3% SiO2, making it suitable as a refractory material. The XRD analysis revealed the presence of alphaquartz as the dominant crystal phase, which is desirable for refractory applications. The FTIR analysis indicated the absence of hydroxyl (-OH) groups. This indicates a low risk of failure and damage such as spalling, cracking and other forms of damage when produced into bricks. The TGA and DTA displayed significant mass losses and large endothermic bands, which were connected to the dehydroxylation of the quartz rock samples. Based on the demonstrated qualities, the quartz rock sample could be subjected to thermal processing. This study therefore established that Ijero-Ekiti quartz is a suitable raw material for refractory applications due to its high purity, alpha-quartz dominant crystal phase, absence of hydroxyl groups, and uniform morphology. [ABSTRACT FROM AUTHOR]

For low-temperature thermoelectric applications, a bulk-phase inorganic/organic composite is prepared by introducing a conducting polymer, which is recognized as a potential organic thermoelectric material, into a representative inorganic thermoelectric material (n-type Bi2Te3). A conducting polymer, PEDOT:PSS, was chosen to prepare the Bi2Te3/PEDOT:PSS composite, wherein an intimate interface was formed between Bi2Te3 and PEDOT:PSS. The work function difference between Bi2Te3 and PEDOT:PSS created an energy barrier at the interface, possibly facilitating selective charge carrier transport depending on the energy levels of the carrier (i.e., energy filtering effect), thereby contributing to an enhancement in the Seebeck coefficient. The composite exhibited a completely different bipolar conduction tendency from pristine Bi2Te3, inducing a significant variation in the temperature dependence of the Seebeck coefficient. Furthermore, the interface may affect the carrier and phonon scattering probabilities, resulting in a considerable reduction in thermal conductivity. The composite adjustment was intensively studied to regulate the electrical and thermal properties using the energy filtering effect along with the carrier and phonon scattering probabilities, resulting in a noticeably enhanced thermoelectric performance. The temperature dependence of the performance was effectively adjusted using the bipolar conduction tendency, thereby affording the Bi2Te3/PEDOT:PSS composite exhibiting consistently high ZT values over the wide temperature range of 25–275 °C. The thermoelectric performance of Bi2Te3/PEDOT:PSS was competitive with that of previously reported high-performance n-type Bi2Te3-based analogs. The Bi2Te3/PEDOT:PSS composite is a promising n-type candidate for diverse low-temperature thermoelectric applications as a p-type Bi2Te3 counterpart. [ABSTRACT FROM AUTHOR]

Developing alternative eco-friendly construction materials is an important factor in sustainable development. Besides, one of the main ways to achieve this goal is the use of earthen materials in construction. In this respect, this study aims to investigate the feasibility of using Alfa fibers (Stipa tenacissima L.) and brick waste in the production of compressed earth blocks (CEB). Hence, the effects of Alfa fibers on the mechanical and thermal performance of CEB containing brick waste are analyzed. Brick waste content was fixed at 20% after an optimization study based on plasticity requirements, while Alfa fibers content varied from 0 to 0.5% of the dry weight of the block. Plain (unreinforced) CEB and fiber-reinforced CEB were tested for physical properties (density and absorption), compressive strength, and thermal behavior (conductivity and diffusivity). The results showed that Alfa fibers lightened the CEB. Also, adding Alfa fibers with a concentration of 0.5% increases the capillary absorption and the compressive strength by 40% and 111.25%, respectively. In terms of thermal properties, it is observed that using Alfa fibers improves the insulation aspect of the composite. Specifically, the thermal conductivity reduced by 13%. In all, using Alfa fibers and waste brick materials in CEB could be a promising solution to produce sustainable material with improved mechanical and thermal properties, contributing to the circular economy. [ABSTRACT FROM AUTHOR]

High-performance polymer nanocomposites utilizing different-sized nanofillers had a lot of interest recently. Due to their distinct structural, and thermal characteristics. Multi-wall carbon nanotubes (MWCNT) and nanoclay (NC) have the most interest among the numerous types of reinforcing as filler elements for a polymer. The formation of hybrid from MWCNT and NC at various loadings (0.5%, 1%, and 2wt%) on the characteristics of epoxy polymer have been assessed in this work. The specimens have been created using solution blending procedures with the addition of solvent ethanol at a ratio of 1:1 for dispersed nanofillers, and then they have been re-mixed with epoxy. Tests like X-Ray diffraction (XRD), and thermal conductivity were used to identify properties of epoxy. According to the test results, the thermal conductivity rise as the filler content rises at 1wt%, then start to decrease after 1wt%. The sample with the hybrid filler loading of 1 wt% produced the best performance. Since hybrid epoxy exhibits the best result of the thermal conductivity 135% over MWNT and NC nanocomposites of 1 wt.% reached 0.3568 W/m.K in the increased thermal conductivity property. By examining the EP nanocomposites XRD pattern. The hybrid of epoxy nanocomposites exhibits all of the NC and MWCNT characteristic peaks. Since interactions between the filler and the epoxy cause a shift in the peak location of 1wt%. Due to the homogeneity of the nanofillers entire epoxy matrix, there may be changes in the intensity or location of the peaks at 1% for 2θ= 20.13°, which corresponds to an interlayer distance of d=0.461nm. [ABSTRACT FROM AUTHOR]

Increasing the absorption ability of electromagnetic waves by using the graphite and silicon carbide (SiC) crucible coated with a thin layer of yttrium oxide (Y2O3) was obtained in the experimental process of expanding the recycled residual glass for cellular glassceramic making without affecting the physical, thermal, mechanical, and microstructural features compared to products made by known conventional or unconventional techniques. The heating rate reached very high values (between 25.5-31.5 °C/min) compared to the known techniques without affecting the microstructural homogeneity of specimens. The features of material that give it excellent thermal insulation properties for possible using as a building material (density between 0.23-0.33 g·cm-3, heat conductivity between 0.036-0.049 W·m-1·K-1, porosity between 84.3-89.1 %, compressive strength between 1.28-1.52 MPa, and water absorption under 1.6 vol. %) have not changed compared to the products usually manufactured in the world by conventional methods. [ABSTRACT FROM AUTHOR]

All buildings, regardless of their function, should exhibit appropriate durability and aesthetics while avoiding a negative impact on the environment. The selection of building materials is increasingly crucial in this regard. Each material possesses distinct strength, technical, or production parameters. However, with regulations becoming more stringent concerning the maximum energy consumption of buildings, it is imperative to scrutinize their thermal properties and the associated thermal conductivity coefficient (?). The article conducts an analysis of available technologies for constructing external partitions in single-family housing and their influence on energy losses within the building. Popular building materials, such as cellular concrete, ceramic hollow bricks, prefabricated expanded clay concrete walls, and a wooden frame structure, were examined. [ABSTRACT FROM AUTHOR]

In this study, the effects of ball milling (BM) technique and carbon nanotube (CNT) content on the thermal and mechanical properties of hybrid reinforced composites were investigated. The composites were prepared using glass fiber (GF), novolac resin (No), and CNTs with different wt% (1, 2, and, 4). Various milling times were used to optimize the entanglement/agglomeration of CNTs in the polymer matrix and subsequently enhance the final thermal and mechanical properties. Through precise investigations, it was found that the nanocomposite with 2 wt% CNT reinforcement, subjected to 2 h of BM, exhibited remarkable enhancements in key properties. The tensile strength was significantly improved to 45.6 MPa, while the elastic modulus reached 3.419 GPa. Hardness was measured at 96 HRM, and thermal conductivity was enhanced to 0.463 W/mK. Moreover, this sample demonstrated a weight loss that was 43.65% lower compared to the sample reinforced with 1 wt% CNT and subjected to 1 h of BM. Overall, this study highlights the importance of optimizing the milling time and CNT content in the preparation of polymer nanocomposites, and it provides valuable insights for the development of advanced materials with superior performance in various applications. [ABSTRACT FROM AUTHOR]

Measurement of thermal properties of thin films is challenging. In particular, thermal characterization is very difficult in semi-transparent samples. Here, we use two photothermal methods to obtain information about the thermal diffusivity as well as thermal conductivity of azoheteroarene functionalized polymer thin layers. The photothermal beam deflection (PBD) method is employed to gather data directly on thermal conductivity and thermal diffusivity, while the thermal lens (TL) method is employed to measure the effective thermal diffusivity. Consequently, the thermal diffusivity of the layers is indirectly estimated from the effective thermal diffusivity using a well-established theoretical relationship. Despite the utilization of distinct methods, our study reveals a remarkable consistency in the highly accurate results obtained from both approaches. This remarkable agreement reaffirms the reliability and mutual compatibility of the employed methods, highlighting their shared ability to provide accurate and congruent outcomes. [ABSTRACT FROM AUTHOR]

At ultra-high temperatures, resilient, durable, stable material choices are limited. While Carbon/Carbon (C/C) composites (carbon fibers and carbon matrix phases) are currently the materials of choice, zirconium carbide (ZrC) provides an option in hypersonic environments and specifically in wing leading edge (WLE) applications. ZrC also offers an ultra-high melting point (3825 K), robust mechanical properties, better thermal conductivity, and potentially better chemical stability and oxidation resistance than C/C composites. In this review, we discuss the mechanisms behind ZrC mechanical, thermal, and chemical properties and evaluate: (a) mechanical properties: flexure strength, fracture toughness, and elastic modulus; (b) thermal properties: coefficient of thermal expansion (CTE), thermal conductivity, and melting temperature; (c) chemical properties: thermodynamic stability and reaction kinetics of oxidation. For WLE applications, ZrC physical properties require further improvements. We note that materials or processing solutions to increase its relative density through sintering aids can have deleterious effects on oxidation resistance. Therefore, improvements of key ZrC properties for WLE applications must not compromise other functional properties. We suggest that C/C-ZrC composites offer an engineering solution to reduce density (weight) for aerospace applications, improve fracture toughness and the mechanical response, while addressing chemical stability and stoichiometric concerns. Recommendations for future work are also given. [ABSTRACT FROM AUTHOR]

Complex thermoelectric materials composed of multiple phases with order/disorder mixing feature have drawn intense attention due to their high performance. However, some physical mechanisms relevant to thermoelectric properties including the relationship between carrier mobility and disorder extent in these materials are still elusive. Here, a phase‐dependent mobility edge in (Cu2Sn1‐yS3)0.85(CuGaS2)0.15 solid solutions is demonstrated. By control over the mobility edge in these solid solutions by increasing the ratio of tetragonal phase with less disorder, a weakened localization of electronic states and promoted carrier mobility are realized. Combined with reduced lattice thermal conductivity, a record high zT value of 1.22 is attained at 823 K for (Cu2Sn0.92S3)0.85(CuGaS2)0.15 with the lowered mobility edge. The findings shed light on a new route to tuning the electrical and thermal transport properties for complex thermoelectric materials with multiple phases. [ABSTRACT FROM AUTHOR]

The precise control of molten steel temperature in tundish is a key factor to ensure the quality of the cast billets, so it is important to develop permanent lining castables for tundish with low thermal conductivity and bulk density. In this work, the hydrophobic modification of pearlescent sand was carried out with hydrogen silicone oil, and 3% of modified pearlescent sand was added to mullite‐bauxite castable to realize its low thermal conductivity and light weight. It is found that modified pearlescent sand still has good hydrophobicity at 350°C, the addition of modified pearlescent sand effectively increases the apparent porosity and reduces the bulk density of the castable. At 1500°C, the bulk density of modified pearlescent sand‐castable is 25.54% less than that of conventional castable. Compared with conventional castable, the mechanical properties and thermal shock resistance of modified pearlescent sand castable are worse, but they are sufficient to meet the use conditions of tundish permanent lining castable. At 600–1000°C, the thermal conductivity of the modified pearlescent sand castable is about 30% lower than that of the conventional castable, which proves that the addition of modified pearlescent sand can significantly improve the thermal insulation performance of mullite‐bauxite castable. [ABSTRACT FROM AUTHOR]

First‐principles calculations are employed to explore the elastic anisotropy and thermal properties of Mg–Ti–O compounds (MgTiO3, MgTi2O5, and Mg2TiO4). The structure parameters used in this work are in good agreement with other theoretical and experimental results. The mechanical stability and ductile nature are demonstrated. The elastic anisotropy is characterized by different anisotropy indexes, three‐dimensional (3D) surface constructions, and two‐dimensional (2D) projections of Young's modulus. Besides, the sound velocities, Debye temperature, and minimum thermal conductivity are also investigated from the elastic modulus. The obtained results can provide references for future experimental investigations and engineering applications of these Mg–Ti–O compounds. [ABSTRACT FROM AUTHOR]

• Molecular dynamics method was implemented. • Nano refrigerants include Freon-134a and Freon-407a as base fluids and Cu as nanoparticles. • The density, velocity, and temperature profiles are investigated. • Freon-407a base fluid shows a better thermal performance. • Nano-refrigerant with Freon-407a base fluid has more heat flux (1028 W/m2). Nano-refrigerants, which are the suspensions of nano-sized particles in a base fluid, were applied in many devices and systems to enhance thermal conductivity and improve heat transfer performance. This work studied the thermal and atomic behavior of two kinds of nano-refrigerants located inside an aluminum nanochannel for 5 ns. The molecular dynamics (simulation method simulated Nano-refrigerants, including R-134a and R-407A as base fluids and copper as nanoparticles. The density, velocity, and temperature profiles were studied to investigate the atomic behavior of the simulated sample. The thermal behavior of structures was studied by examining the phase transition rate, phase change time, thermal conductivity, and heat flux. The results show that R-407A base fluid showed better thermal behavior. The results show that in Cu/R-407A, the phase-changed particle reached 31% in 5 ns, and phase change time was estimated to be 3.91 ns. In contrast, in Cu/R-134a, the samples' phase changed particle and phase change time reached 26% and 4.06 ns. Moreover, the study of heat flux shows that nano-refrigerant with R-407A base fluid had more HF (1028 W/m2) than R-134a (654 W/m2). The results show that the thermal conductivity of R-407A and R-134a nano-refrigerant converged to 0.0975 and 0.0098 W/mK, respectively. [ABSTRACT FROM AUTHOR]

Polymers with high thermal conductivity (TC) and dielectric constant (ε) but low dielectric loss show enormously potential applications in electrical power systems. To enhance the ε and TC while significantly suppressing the loss of β‐silicon carbide whisker (β‐SiCw)/polyvinylidene fluoride (PVDF), in this study, SiO2 shells with different morphologies were constructed on the superficies of β‐SiCw via a facile oxidation method in air atmosphere. The SiO2 shell' morphology on the TC and dielectric performances of the β‐SiCw@SiO2/PVDF are systematically explored as a function of the frequency and filler loading. The β‐SiCw@SiO2/PVDF demonstrate astonishingly restricted loss and meliorative TC when compared to the β‐SiCw/PVDF because the SiO2 shell not only suppresses the β‐SiCw from direct contact with one another and impedes the long‐distance charges migration thereby resulting in rather low loss and leakage conductivity, but also restrains the thermal interfacial resistance via increased interfacial compatibility and interactions. The concurrent enhancement effect in the ε and TC but low loss of the composites is more evident in the crystalline SiO2 interlayer with a high TC compared with amorphous one. These results provide insight into the exploration of composite nanodielectrics with large TC and ε but low loss for applications in electrical power systems. Highlights: Core@shell structured β‐SiCw@SiO2/PVDF were obtained by a facile oxidation.The great reduction in both loss and conductivity is attributed to the SiO2 shell.Crystalline SiO2 shell can improve the composites' thermal conductivity.The SiO2 shell prevents long‐range carrier migration. [ABSTRACT FROM AUTHOR]

A new melt mixing and in‐situ exfoliation method based on the synergy of multi‐source pulsating flow and phase transition (MSPFPT) was reported. The corresponding device was also developed, and the structure and mixing process of the mixer were introduced in detail. High‐density polyethylene (HDPE)/expanded graphite (EG) composites were prepared via this new mixer, and microstructure and thermal properties of the composites were comprehensively investigated. Morphological analyses demonstrate that MSPFPT method promotes the efficient exfoliation and uniform dispersion of EG. The well‐exfoliated EG layers form more thermal conductive paths in the composites prepared by MSPFPT, increasing thermal conductivity from 0.47 of pure HDPE to 1.16 W/(m·K) with 9 wt.% EG. The crystallinity degree of HDPE is increased by 11.1%. The increment of crystallinity reduces phonon scattering, which further confirms that MSPFPT method can significantly improve the thermal performance. The research provides a practical strategy for fabricating high‐performance composites filled with layered fillers. [ABSTRACT FROM AUTHOR]

Terbium aluminum garnet (Tb3Al5O12, TAG) ceramics have become a promising magneto‐optical material owing to the outstanding comprehensive performance, including the magneto‐optical, thermal, and mechanical properties. Fine‐grained TAG ceramics with high optical quality and mechanical properties have attracted much attention. In this study, TAG ceramics with fine grains and high optical quality are fabricated successfully by a two‐step sintering method from co‐precipitated nano‐powders. After pre‐sintered at 1525°C in vacuum and hot isostatic pressed at 1600°C, the in‐line transmittance of TAG ceramics reaches 81.8% at 1064 nm, and the average grain size is 7.1 μm. The Verdet constant of TAG ceramics is −179.6 ± 4.8 rad T−1 m−1 at 633 nm and −52.1 ± 1.9 rad T−1 m−1 at 1064 nm, higher than that of commercial Tb3Ga5O12 crystals. The thermal conductivity of TAG ceramics is determined from 25 to 450°C, and the result is 5.12 W m−1 K−1 at 25°C and 3.61 W m−1 K−1 at 450°C. A comparison of mechanical properties between large‐ and fine‐grained TAG ceramics fabricated under different conditions is conducted. The fine‐grained TAG ceramics possess a bending strength of 226.3 ± 16.4 MPa, which is 9.7% higher than that of the large‐grained ceramics. These results indicate that reducing the grain size on the premise of high optical quality helps improve the comprehensive performance of TAG ceramics. [ABSTRACT FROM AUTHOR]

The 3ω method is a well-established thermal technique used to measure the thermal conductivity of materials and the thermal resistance of interfaces. It has significant advantages over other steady state and transient thermal techniques in its ability to provide spatially resolved thermal property measurements over a wide range of thermal conductivity. Despite its advantages, it has been restricted to lab-scale use because of the difficulty involved in sample preparation and sensor fabrication and is limited to non-metallic substrates. High-throughput 3ω measurements with reusable sensors have not been realized yet. In this work, we demonstrate a method of applying reusable 3ω sensors fabricated on flexible polyimide films to measure bulk and spatially resolved thermal properties. We establish the limits of thermal conductivity measurement with the method to be 1 to 200 W/mK, and within the measurement limit, we verify the method by comparing the measured thermal conductivities of standard samples with established values. From the 3ω measurements, we also determine the thermal resistance of an interlayer of thermal grease as a function of pressure and compare it against the resistance calculated from direct thickness measurements to demonstrate the ability of this method to provide spatially resolved subsurface information. The technique presented is general and applicable to both metallic and non-metallic substrates, providing a method for high-throughput 3ω measurements with reusable sensors and without considerable sample preparation. [ABSTRACT FROM AUTHOR]

This research paper presents the results and analysis obtained via the evaluation of calcium nitrate as an effective stabilizer to alter the thermal properties as well as improve the compressive strength of frost-susceptible soil. Two silty sand soils with 15% and 25% fines content that are categorized as high to very high frost-susceptible soil were considered and treated with varying dosages of calcium nitrate contents (1.5%, 3.0%, 4.5%, 10%, 15%, and 20% of soil weight). The thermal properties, including thermal hysteresis, thermal conductivity, specific heat capacity, freezing point depression, and phase changes (freezing and thawing point) were determined for the untreated and treated soil samples. It was observed that the treated samples' thermal properties were significantly altered with respect to untreated soils. The effects of fines content on the thermal properties were evaluated using a stabilizer–silt content ratio. The threshold calcium nitrate dosage content was established, and a new correlation was established to evaluate the freezing point and thawing point. The unconfined compressive strength (UCS) tests performed on the treated soils depicted a significant increase in compressive strength compared to the untreated soil. Further analysis showed that fines content has a significant role to play on the compressive strength of treated silty sand. A qualitative analysis performed on images from a scanning electron microscope (SEM) showed that increasing the calcium nitrate dosage reduced the pore size and improved the cementation between the sand and silt grains. [ABSTRACT FROM AUTHOR]

Due to its mechanical, rheological, and chemical properties, high-density polyethylene (HDPE) is commonly used as a material for producing the pipes for transport of various media. Low thermal conductivity (0.4 W/mK) narrows down the usage of HDPE in the heat exchanger systems. The main goal of the work is to reduce the vertical depth of the HDPE pipe buried in the borehole by increasing the thermal conductivity of the material. This property can be improved by adding certain additives to the pure HDPE matrix. Composites made of HDPE with metallic and non-metallic additives show increased thermal conductivity several times compared to the thermal conductivity of pure HDPE. Those additives affect the mechanical properties too, by enhancing or degrading them. In this research, the thermal conductivity and tensile properties of composite made of HDPE matrix and two types of additives, expanded graphite (EG) and boron nitride (BN), were tested. Micro-sized particles of EG and two different sizes of BN particles, micro and nano, were used to produce composite. The objective behind utilizing composite materials featuring dual additives is twofold: firstly, to enhance thermal properties, and secondly, to improve mechanical properties when compared with the pure HDPE. As anticipated, the thermal conductivity of the composites exhibited an eightfold rise in comparison to the pure HDPE. The tensile modulus experienced augmentation across all variations of additive ratios within the composites, albeit with a marginal reduction in tensile strength. This implies that the composite retains a value similar to pure HDPE in terms of tensile strength. Apart from the enhancement observed in all the aforementioned properties, the most significant downside of these composites pertains to their strain at yield, which experienced a reduction, declining from the initial 8.5% found in pure HDPE to a range spanning from 6.6% to 1.8%, dependent upon the specific additive ratios and the size of the BN particles. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents may develop a pivotal role in future technologies considering sustainability and safety as pivotal aspects for chemistry developments. The possible application of these fluids for heat transfer operations is of great relevance for which the knowledge of thermal properties such as thermal conductivity is required as well as inferring structure–property relationships which allow reverse design of the fluids according to the technological requirements. Considering the technological relevance of this property, the available literature on the thermal conductivity for deep eutectic solvents is critically discussed showing strengths and weaknesses. The analysis of the state-of-the-art shows the future needs in this research field considering the application of these solvents for thermal-related technologies. The review indicates the scarcity of reliable experimental data and the need of predictive methods, which could be used for process design and solvent screening purposes. Likewise, considering the relevance of developing predictive methods for in silico design of these fluids according to industrial needs, the available predictive theoretical approaches are analysed showing their reliability as well as future needs. Finally, considering the need of developing suitable and reliable structure–property relationship, the molecular level basis of thermal conductivity in deep eutectic solvents is discussed, showing the role of hydrogen bonding and the effects rising from the involved hydrogen bond donors and acceptors as well as the eutectic compositions. This work reports the first literature review and analysis on thermal conductivity for deep eutectic solvents considering an experimental and theoretical approach as well as providing support for the molecular basis of this technologically relevant property, thus contributing to the development of environmentally friendly materials for thermal-related technologies. [ABSTRACT FROM AUTHOR]

Thermal properties such as thermal conductivity, heat capacity, and thermal diffusivity and physical properties such as calorific value, density, and kinematic viscosity of liquid fuels play a significant role in the combustion process. These properties vary with the chemical structures and the fatty acid profiles of biodiesels. Making correlations for various properties with respect to fatty acid profile helps to analyze the combustion process. Most of the reported works generated correlations using data taken from the literature, and the correlations based on the fatty acid profile for thermal properties of biodiesel are unavailable. As coconut oil, sunflower oil, and palm oil have entirely different fatty acid profiles, in this study, biodiesels produced from these three waste cooking oils and their three hybrids (each in a 1:1 ratio) were used for biodiesel production, followed by correlation formulation. Higher thermal conductivity (0.2211 W mK−1) and thermal diffusivity (0.2459 mm2 s−1) and lower heat capacity (0.8993 MJ m−3 K−1), density (862.8 kg m−3), kinematic viscosity (2.71 cSt), and calorific value (36.73 cSt) were observed for coconut-based biodiesels compared with other biodiesels. The addition of coconut content to hybrid biodiesel enhanced thermal conductivity and thermal diffusivity and reduced heat capacity, density, and kinematic viscosity. From the experimental data of thermal conductivity, heat capacity, thermal diffusivity, density, kinematic viscosity, and calorific value, empirical correlations were proposed with the fatty acid profile. Good agreement was obtained between experimental and calculated values. [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]

Novel bulk SiOC/spodumene composites have been developed by spark plasma sintering (SPS) at relatively low temperature (1200–1400 °C). Spodumene is a cheap and natural available lithium aluminosilicate mineral which acts as meltable/active filler. At 1300–1400 °C, the Al migrates toward the glassy matrix producing a Si-Al-O network and the crystallization of α-cristobalite. The C free phase also experiences a deep transformation. The epitaxial growth of few-layered graphene over SiC particles occurs at 1400 °C. An increase in the phonon transport is observed (36%, 1.28 – 2.14 Wm−1K−1) associated to the reduction of the interface resistance between the partially crystallized SiO 2 matrix and the SiC nano-wires/graphene-like carbon conductive phase. The electrical conductivity increases (1.14 ×10−2 – 8.1 Sm−1) due to the densification reached and an increasing ordering degree of the tortuous C free phase with a high quality of interconnection and crystallization. Raman parameters are determinant to understand the thermal and electrical response. • Spodumene was used for the first time to rise k and σ of SiOC/spodumene composites. • Raman parameters and densification are crucial to understand phonon/electron response. • The epitaxial growth of few-layered graphene over SiC particles occurs at 1400 ºC. • k boosts by the reduction of the interface resistance between SiO 2 /SiC nano-wires/C. • rises by densification and increasing ordering degree of the tortuous C free phase. [ABSTRACT FROM AUTHOR]

The fabrication of high-entropy ceramics has recently expanded the pool of ultra-high temperature ceramics (UHTCs). To properly assess the suitability of these new types of ceramics for advanced aerospace applications, it is of vital interest to extend the characterizations beyond ambient conditions. Here, we have studied the thermal and ablation properties of a high-entropy diboride (HEB): (Hf 0.2 Zr 0.2 Ti 0.2 Ta 0.2 Nb 0.2)B 2. The thermal conductivity of the HEB increases as a function of temperature and becomes comparable to that of other UHTCs at high temperatures. The electron dominated thermal conductivity of HEB is also nearly isotropic along different crystallographic orientations. The temperature-dependent volumetric heat capacity of HEB is measured and found to remain in agreement with that of ZrB 2. Additionally, both material systems possess nearly the same ablation resistance. The multitudes of characterizations performed in this study establishes the suitability of HEB for high thermal load applications in extreme environments. [ABSTRACT FROM AUTHOR]

In this work, we study thermoelectric properties of GeTei-based alloys, doped with bismuth, with partial substitution of lead for germanium: Ge0.86Pb0.1Bi0.04Te. The aim of the study is to explore the possibility of increasing the thermoelectric efficiency of a compound by combining optimal doping and isovalent substitution to improve the electronic properties with a simultaneous decrease of the lattice thermal conductivity. We studied alloy samples prepared in two different research laboratories using similar, but not completely identical procedures. It is shown that the electronic (thermoelectric power and electrical conductivity) properties of the samples of the two groups are in good agreement with each other. The properties of alloys depend on the thermal history of the samples due to the presence at temperatures of 600–800 K of a phase transition from a low-temperature rhombohedral to a high-temperature cubic structural modification and missibility gap in GeTe–PbTe quasibinary system below 870 K. The thermoelectric figure of merit of alloys reaches a maximum value of 1.5 at a temperature of about 750 K. [ABSTRACT FROM AUTHOR]

This work aims to estimate temperature-dependent thermal conductivity and heat capacity given measurements of temperature and heat flux at the boundaries. This estimation problem has many engineering and industrial applications, such as those for the building sector and chemical reactors. Two approaches are proposed to address this problem. The first method uses an integral approach and a polynomial approximation of the temperature profile. The second method uses a numerical solver for the nonlinear heat equation and an optimization algorithm. The performance of the two methods is compared using synthetic data generated with different boundary conditions and configurations. The results demonstrate that the integral approach works in limited scenarios, whereas the numerical approach is effective in estimating temperature-dependent thermal properties. The second method is also extended to account for noisy measurements and a comprehensive uncertainty quantification framework is developed. [ABSTRACT FROM AUTHOR]

The thermal insulation properties of building walls are critical to the overall energy efficiency and comfort of a building. One important factor that can affect these properties is the type of bricks used in construction. Bricks can vary in their geometry and thermal coefficient, which can impact their ability to transfer heat through the wall. The geometry of a brick can affect its thermal properties by altering the amount of air trapped within it and the surface area available for heat transfer. Hollow bricks or those with complex geometries may have lower thermal conductivity than regular solid bricks due to the air pockets trapped within them. Conversely, larger surface areas on the exterior of the brick can increase heat transfer. The thermal coefficient of clay, a common material used in brick production, is another important factor. Clay has relatively low thermal conductivity, meaning it is a poor conductor of heat. However, the quality of the clay, as well as the firing temperature and duration used in brick production, can impact its thermal coefficient. Higher firing temperatures and longer firing times can result in a more compact and dense clay brick, which can improve its thermal properties. In summary, the thermal insulation properties of building walls can be significantly affected by the type of bricks used in their construction. It is important to consider the geometry and thermal coefficient of the bricks when designing a building to achieve the desired level of thermal insulation. By selecting bricks with appropriate properties, designers can help to improve the energy efficiency and comfort of the building while reducing its environmental impact. [ABSTRACT FROM AUTHOR]

The aim of this work is to investigate the possibility of recycling Walnut Shell wastes (WS) as fine aggregates in lightweight self-compacting mortar (SCM). In the experimental procedure, the natural sand was partially replaced by the WS waste at various replacement ratios (0; 10; 20; 30 and 40%). The thermal conductivity and some physic-mechanical properties of the SCM containing WS were studied and compared with control SCM (CSCM). The test results showed that, depending on the amount of WS aggregate, unit weight and thermal conductivity of concrete were reduced and the capillary water absorption was increased with the use of WS aggregates and for all the lightweight SCMs considered. Moreover, reductions in mechanical properties of concretes have been obtained with decreasing concrete unit weights. In addition, substitution ratio of 30% was found to be the optimum volume ratio of WS for getting lightweight structural SCM with appropriate fresh and hardened properties. [ABSTRACT FROM AUTHOR]

High temperature in deep mines has become the main concern to limit the production capacity of mines. To mitigate the adverse impact of the underground high-temperature environment on mine production, an orthogonal test was used to design an experimental scheme, i.e., the contents of tailings, glass beads, and ordinary Portland cement PC32.5 (PC) were set as the main horizontal factors to prepare thermal insulation material samples with different combination ratios. Compressive strength and thermal conductivity were investigated, as well as the microstructure. Based on the response surface method (RSM), the interaction between the horizontal factors was explored and analyzed using Design Expert 12 software, and thus non-linear fitting equations were established with the volume fractions of the main horizontal factors as independent variables and compressive strength and thermal conductivity as dependent variables in the analysis parameters of thermal insulation materials. The results showed that errors between the fitted calculated values of compressive strength and thermal conductivity and the experimental results were only 0.42% and 1.2%, respectively, indicating that the process parameters obtained with the optimum fitting ratio under the established fitting equation are highly reliable and have excellent compressive strength and thermal insulation properties. The optimized results obtained by combining the orthogonal method and the RSM show accurate prediction and applicability in the field of thermal insulation materials in mines. [ABSTRACT FROM AUTHOR]

Bulk crystals of β-Ga2O3 were successfully grown by the edge-defined film-fed growth method. The crystalline quality of the obtained crystals was analyzed by the method of x-ray diffractometry. The full width at half maximum of the rocking curve was about 72 arcsec. The optical bandgap was determined by analyzing the optical transmission spectra and amounted to 4.7 eV. The hot disk method was used to obtain the thermal conductivity of the sample along the [001] direction in the temperature range from 30 to 120 °C. The maximum value of thermal conductivity obtained at 30 °C was 9.25 W/(m K). [ABSTRACT FROM AUTHOR]

Propylene glycol-based MWCNT (multi-walled carbon nanotubes) nanofluids were prepared in the framework of a two-step method and by using a suitable PVP (polyvinyl pyrrolidone) dispersant. The BBD (Box-Behnken design) model was exploited to analyze 17 sets of experiments and examine the sensitivity of the absorbance to three parameters, namely the concentration of MWCNT, the SN ratio (mass ratio of carbon nanotubes to surfactants) and the sonication time. The results have revealed that, while the SN ratio and concentration of MWCNT have a strong effect on the absorbance, the influence of the sonication time is less important. The statistical method of analysis of variance (ANOVA) was further used to determine the F- and p-values of the model. Five experiments were run to validate this approach. Since sample 2 was found to display the greatest absorbance, it was selected for stability monitoring as well as thermal conductivity and viscosity measurements. This sample has been found to be stable; the viscosity decreased with increasing temperature; the addition of MWCNT nanoparticles was more effective in improving the thermal conductivity of propylene glycol than other methods in the literature. Moreover, the MWCNT nanofluid based on propylene glycol exhibited higher thermal conductivity at low temperatures. [ABSTRACT FROM AUTHOR]

Nitrile rubber is a widely used rubber, so its basic mechanical properties are very important. In order to improve the mechanical properties of nitrile butadiene rubber (NBR), Mg‐Al hydrotalcite was introduced into NBR by mechanical blending and hot pressing, and the mechanical properties of the composites were studied. The results show that, compared with NBR, the maximum MH‐ML of 2%LDH/NBR composites reaches 1.795 N·m, and an is improved by 8.7%. The T90 of NBR and 2%LDH/NBR composites insignificant changed. In terms of mechanical performance, the optimal performance is achieved when two parts of layered double hydroxide (LDH) are added. Compared with the original NBR, the tensile elongation at break, tear strength, and 100% modulus stress increased by 11.6%, 7.1%, and 29.1%, respectively. The addition of LDH also has a certain influence on the thermal conductivity of the composites. Compared with the original NBR, the peak thermal conductivity of NBR with two parts of LDH increased by 2.4 mW. Under the condition of low filling, the mechanical properties such as elongation at break and tear strength of LDH/NBR composites have been improved, which provides a reference for the development of mechanical properties research of NBR. [ABSTRACT FROM AUTHOR]

Copper (Cu) and tungsten (W) possess exceptional electrical and thermal conductivity properties, making them suitable candidates for applications such as interconnects and thermal conductivity enhancements. Solution-based additive manufacturing (SBAM) offers unique advantages, including patterning capabilities, cost-effectiveness, and scalability among the various methods for manufacturing Cu and W-based films and structures. In particular, SBAM material jetting techniques, such as inkjet printing (IJP), direct ink writing (DIW), and aerosol jet printing (AJP), present a promising approach for design freedom, low material wastes, and versatility as either stand-alone printers or integrated with powder bed-based metal additive manufacturing (MAM). Thus, this review summarizes recent advancements in solution-processed Cu and W, focusing on IJP, DIW, and AJP techniques. The discussion encompasses general aspects, current status, challenges, and recent research highlights. Furthermore, this paper addresses integrating material jetting techniques with powder bed-based MAM to fabricate functional alloys and multi-material structures. Finally, the factors influencing large-scale fabrication and potential prospects in this area are explored. [ABSTRACT FROM AUTHOR]

The environment-friendly components coupled with the ability to mimic the simplicity and originality of nature necessitate advanced sustainable materials with structural capabilities for energy-efficient applications. The use of feedstock deriving from plant-based, renewable organic material to produce nanofibril that embodies enhanced insulating properties and high mechanical strength constitutes an efficient development strategy. Herein, a free-standing, hierarchical superinsulation membrane by leveraging the principle of the bottom-up method is reported. The electrospun cellulose nanofibrils/aerogel-based core layer provides exceptional thermal properties with its thermal conductivity of 10.2mWm-1K-1. The lightweight, flexible, and durable paper-like membrane features a tensile strength of 11.3 MPa and a bending rigidity in the order of 4.6 cNmm-1. The hydrophobic superinsulation membrane material also exhibits a Δ T of ≈25 °C under continuous sunlight illumination and allows thermal runaway mitigation of rechargeable lithium-ion batteries. All the aforementioned properties position this hybrid superinsulation membrane as a promising material for energy-saving thermal management applications. [ABSTRACT FROM AUTHOR]

Durian is Malaysia's most popular seasonal fruit, but less than half of the durian fruit is consumed as food. Durian is a type of fruit with a high percentage of waste, which becomes an environmental problem when discarded into the landfill site. Therefore, it is important to utilise durian waste as a potential natural fibre-based composite reinforcement. Durian skin residue is recognised as one of the potential lignocellulosic materials to replace wood in the insulation board industry. The present study aims to develop a low-cost insulation board using durian skin residues as reinforcing materials. Single-layer mats were manually formed, followed by hot pressing using polymeric methane diphenyl diisocyanate (PMDI) resin. The effect of different percentages of PMDI resin (0, 6, 8 and 10%) on the board's physical, mechanical, morphological, and thermal properties was investigated. It was found that 6% PMDI resin is the optimised resin amount to produce PMDI/durian skin fibre composite, and the board with 6% PMDI has the maximum static bending due to enhanced cross-linking by the fibre. In terms of thermal stability and conductivity, the incorporation of 6% of PMDI is considered the best formulation based on the value achieved. The overall results indicated that this study addresses a low-cost innovation for commercial insulation boards as it utilises durian waste and a low dosage of PMDI for implementation in the building and construction industry. [ABSTRACT FROM AUTHOR]

Policymakers regularly implement stricter building energy-efficiency codes towards curtailing building energy use. Inevitably, super-insulating materials such as Vacuum Insulation Panels (VIPs) are essential to satisfy such codes. VIPs have been applied to buildings for over two decades now, with many lessons learned. Generally, the thermal conductivity values of VIPs often reported in the literature are the center-of-panel thermal conductivity (λcop) and effective thermal conductivity (λeff), factoring thermal bridges. However, there are other indexes, such as λ90/90 (declared value in the 90% percentile with a confidence of 90%) and λcop,90/90,aged (factoring aging), that increase consistently and reliably in the declared thermal conductivity value for VIPs. These indexes are scarcely computed and hardly reported. The main aim of this study was to examine the different declared thermal conductivity values of VIP-based guidelines, such as draft ISO DIS 16478, and evaluate their implications on annual building energy consumption. The main study constitutes four parts: (1) experimental evaluation of the thermal properties of pristine and aged VIP samples, (2) computation of thermal conductivity indexes, (3) numerical investigation of thermal conductivity indexes based on a reference building, and (4) related building energy implications. The mean λcop for 10 VIP samples was 0.0042 W/(mK) and increased to 0.0073 W/(mK) for  λ 90 / 90 , bridge, aged. Results show a significant bearing on building energy performance of as much as 2.1 GJ. [ABSTRACT FROM AUTHOR]

This experimental study aimed to characterize the thermal properties of ex vivo porcine and bovine kidney tissues in steady-state heat transfer conditions in a wider thermal interval (23.2–92.8 °C) compared to previous investigations limited to 45 °C. Thermal properties, namely thermal conductivity (k) and thermal diffusivity (α), were measured in a temperature-controlled environment using a dual-needle probe connected to a commercial thermal property analyzer, using the transient hot-wire technique. The estimation of measurement uncertainty was performed along with the assessment of regression models describing the trend of measured quantities as a function of temperature to be used in simulations involving heat transfer in kidney tissue. A direct comparison of the thermal properties of the same tissue from two different species, i.e., porcine and bovine kidney tissues, with the same experimental transient hot-wire technique, was conducted to provide indications on the possible inter-species variabilities of k and α at different selected temperatures. Exponential fitting curves were selected to interpolate the measured values for both porcine and bovine kidney tissues, for both k and α. The results show that the k and α values of the tissues remained rather constant from room temperature up to the onset of water evaporation, and a more marked increase was observed afterward. Indeed, at the highest investigated temperatures, i.e., 90.0–92.8 °C, the average k values were subject to 1.2- and 1.3-fold increases, compared to their nominal values at room temperature, in porcine and bovine kidney tissue, respectively. Moreover, at 90.0–92.8 °C, 1.4- and 1.2-fold increases in the average values of α, compared to baseline values, were observed for porcine and bovine kidney tissue, respectively. No statistically significant differences were found between the thermal properties of porcine and bovine kidney tissues at the same selected tissue temperatures despite their anatomical and structural differences. The provided quantitative values and best-fit regression models can be used to enhance the accuracy of the prediction capability of numerical models of thermal therapies. Furthermore, this study may provide insights into the refinement of protocols for the realization of tissue-mimicking phantoms and the choice of tissue models for bioheat transfer studies in experimental laboratories. [ABSTRACT FROM AUTHOR]

In this study, a carbon nanotube‐glass bubble/polyamide 6 (CNT‐GB/PA6) multiscale hybrid composite was manufactured. Through a coagulation process including CNT and GB, a segregated network was formed to produce a composite structure with tunable thermal conductivity. Within the segregated network structure, a complex phenomenon of decrease and increase in thermal conductivity owing to the interaction by CNT and GB, and an equation to predict thermal conductivity through the contents of GB and CNT was formulated. A model to predict the thermal conductivity using the RSM analysis was presented, and the contents of GB and CNT were adjusted according to the required thermal conductivity. It was confirmed through the LFA thermal conductivity measurement that the thermal conductivity increased with GB and CNT contents. Moreover, when 30% of GB was added to the 5 wt% CNT composite, the thermal conductivity increased by about 17%. However, in the experiment to confirm the effect of GB alone, it was confirmed that the thermal conductivity decreased as the GB content increased. Thus, the size of the structural path, which was controlled by the GB content through which electrons pass, played an important role in this study. The results of this study can be used in astronautic fields that require insulation to save energy and in construction engineering where thermal insulation and heat emission are important. [ABSTRACT FROM AUTHOR]

Mullite/glass/nano aluminum nitride (AlN) filler (1–10 wt% AlN) composites were successfully fabricated for the low‐temperature co‐fired ceramics applications that require densification temperatures lower than 950°C, high thermal conductivity to dissipate heat and thermal expansion coefficient matched to Si for reliability, and low dielectric constant for high signal transmission speed. Densification temperatures were ≤825°C for all composites due to the viscous sintering of the glass matrix. X‐ray diffraction proved that AlN neither chemically reacted with other phases nor decomposed with temperature. The number of closed pores increased with the AlN content, which limited the property improvement expected. A dense mullite/glass/AlN (10 wt%) composite had a thermal expansion coefficient of 4.44 ppm/°C between 25 and 300°C, thermal conductivity of 1.76 W/m.K at 25°C, dielectric constant (loss) of 6.42 (0.0017) at 5 MHz, flexural strength of 88 MPa and elastic modulus of 82 GPa, that are comparable to the commercial low temperature co‐fired ceramics products. [ABSTRACT FROM AUTHOR]

An improved method to simultaneously determine the heat capacity, thermal diffusivity, and thermal conductivity of a small-sized material is described. In this method, the heat of a square wave with a superimposed constant component is applied to one side of a plate-shaped sample using a thin-film heater, which is thermally linked to a heat reservoir. The response temperature is measured by a thermometer attached to the heater. In contrast to a previously reported method, the amplitude of the temperature oscillation detected by the thermometer is enhanced by the internal thermal relaxation in the improved method. This feature is advantageous for determining thermal properties with low-heat modulation. We theoretically analyzed the proposed method using a one-dimensional model and demonstrated the method on synthetic quartz (SiO2) and poly(methyl methacrylate) plates in the temperature range of 80–300 K. The thermal properties obtained for both samples using the proposed method were consistent with values reported in the literature. The deviations from the data for the specific heat capacity, thermal diffusivity, and thermal conductivity were estimated to be ∼1%, 2%, and 2%, respectively. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a promising material for thermoelectric power generation. The characterization of thermal transport properties is essential to understanding their applications in thermoelectric devices. The existence of stacking faults, which originate from the "wrong" stacking sequences of Si–C bilayers, is a general feature of SiC. However, the effects of stacking faults on the thermal properties of SiC are not well understood. In this study, we evaluated the accuracy of Tersoff, MEAM, and GW potentials in describing the thermal transport of SiC. Additionally, the thermal conductivity of 3C/4H-SiC nanowires was investigated using non-equilibrium molecular dynamics simulations (NEMD). Our results show that thermal conductivity exhibits an increase and then saturation as the total lengths of the 3C/4H-SiC nanowires vary from 23.9 nm to 95.6 nm, showing the size effect of molecular dynamics simulations of the thermal conductivity. There is a minimum thermal conductivity, as a function of uniform period length, of the 3C/4H-SiC nanowires. However, the thermal conductivities of nanowires weakly depend on the gradient period lengths and the ratio of 3C/4H. Additionally, the thermal conductivity of 3C/4H-SiC nanowires decreases continuously from compressive strain to tensile strain. The reduction in thermal conductivity suggests that 3C/4H-SiC nanowires have potential applications in advanced thermoelectric devices. Our study provides insights into the thermal transport properties of SiC nanowires and can guide the development of SiC-based thermoelectric materials. [ABSTRACT FROM AUTHOR]

The configuration of a continuous and oriented thermal pathway is essential for efficient heat dissipation in the oriented direction. Three-dimensional (3D) conductive filler structures provide a suitable approach for constructing continuous thermal pathways in polymer-based composites. The aluminum nitride/reduced graphene oxide/poly(dimethylsiloxane) (AlN/rGO/PDMS) composite material is made with a 3D foam structure and focuses on reducing GO and forming foam via polyvinyl alcohol (PVA). We analyze the successful fabrication of hybrid fillers and composites using various methods. The fabricated composite with a 3D network filler foam achieves a through-plane thermal conductivity of 1.43 W/mK and achieves 752% higher thermal conductivity compared to pure PDMS, which is superior to composites without 3D foam. The continuous 3D filler structure via freeze-drying and annealing processes provides efficient thermal dissipation in the through-plane direction pathway, which is critical for enhancing thermal conductivity. Therefore, this work produces a polymer composite material with improved thermal conductivity through various processes. [ABSTRACT FROM AUTHOR]

In this study, specimens were prepared from Japanese cedar (Cryptomeria japonica) with different thicknesses to determine the best hot-pressing conditions for wood compression layered structural materials (WCLS) through densification at various temperatures and compressing time conditions. However, residual stress-releasing after densification recovery can cause dimensional instability. To address this issue, the drying set method was combined with the compression-set recovery test to determine the best setting time. As a result, the bending strength and modulus of rupture (MOR) of WCLS increased by 9.98 ± 9.71 to 20.87 ± 13.09% and the modulus of elasticity (MOE) increased by 9.87 ± 11.92 to 22.40 ± 17.97%. The volumetric swelling coefficient (S), water absorption percent (WAP), and equivalent moisture content (EMC) decreased as the drying time increased. The anti-swelling efficiency (ASE) and moisture excluding efficiency (MEE) were found to be the highest at a drying time of 12 h, with values ranging from 13.20 ± 15.11 to 36.46 ± 6.83% and 15.18 ± 1.11 to 19.58 ± 8.31%, respectively. The drying method was found to be effective in increasing dimensional stability. The glass transition temperature (Tg) moved to a lower temperature as the compression-set increased, which was due to plasticization of wood caused by high temperature and pressure. The cell walls of WCLS presented viscous buckling, which provided effective dimensional stability. The thermal conductivity of Japanese cedar and each compression-set WCLS were 0.1863 ± 0.0071, 0.1520 ± 0.0147, 0.1817 ± 0.0106, and 0.1423 ± 0.0137 W/mK, respectively. The thermal conductivity of each WCLS increased with an increase in compression-set, but decreased by 10.67 to 22.52% compared to Japanese cedar. The total electricity energy consumption of each WCLS after 24 h of testing decreased with a trend of 30.50 ± 0.84, 29.83 ± 0.42, 29.57 ± 0.51, and 29.4 ± 0.36 kWH. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs), which can absorb and release large amounts of latent heat during phase change, have been extensively studied for heat storage and thermal management. However, technical bottlenecks regarding low thermal conductivity and leakage have hindered practical applications of PCMs. In this paper, a simple, economical, and scalable absorption polymerization technique is proposed to prepare the polymethyl methacrylate/propyl palmitate/expanded graphite (MPCM/EG) phase change composites by constructing the microencapsulated phase change materials (polymethyl methacrylate/propyl palmitate, MPCM) with core-shell structures in the three-dimensional (3D) EG networks, taking propyl palmitate as the PCM core, polymethyl methacrylate (PMMA) as the shell, and long-chain "worm-like" EG as the thermally conductive networks. This technique proved to be a more appropriate combinatorial pathway than direct absorption of MPCM via EG. The MPCM/EG composites with high thermal conductivity, high enthalpy, excellent thermal stability, low leakage, and good thermal cycle reliability were prepared. The results showed that the MPCM-80/EG-10 composite demonstrated a high thermal conductivity of 3.38 W/(m·K), a phase change enthalpy up to 152.0 J/g, an encapsulation ratio of 90.3%, outstanding thermal stability performance, and long-term thermal cycle reliability when the EG loading is 10% and propyl palmitate is 80%. This research offers an easy and efficient approach for designing and fabricating phase change composites with promising applications in diverse energy-saving fields, such as renewable energy collection, building energy conservation, and microelectronic devices thermal protection. [ABSTRACT FROM AUTHOR]

The structural, electronic, thermal and lattice thermal transport properties of the three hypothetical quaternary Heusler alloys FeRuTiX (X=Si, Ge, Sn) were investigated with the aid of first‐principles calculations. All compounds were found to be semiconducting with a small indirect band gap. Flat bands near the conduction band edge and degenerate multi‐bands near the valance band edge suggest that these systems should exhibit both large Seebeck coefficients and good electrical conductivity. The analysis of the calculated vibrational spectra showed that the three compounds are thermodynamically stable. The computed lattice thermal conductivity indicates that among the three compounds that of FeRuTiSn is rather low at high temperature. Indeed, a low lattice thermal conductivity (∼3.5 Wm−1 K−1 at 1000 K) together with a small electronic band gap (0.51 eV) with an appropriate electronic structure (disperse and flat bands) render FeRuTiSn a promising candidate as a high‐temperature thermoelectric material. [ABSTRACT FROM AUTHOR]

In recent years, the integration of Nanoclay (NC) into concrete has garnered significant global attention due to its potential added benefits and importance in the construction industry. However, the existing literature lacks sufficient experimental validation and empirical analysis pertaining to several unexplored key properties, such as thermal resistance, conductivity, diffusivity, and fire resistance. This study aims to address these knowledge gaps and contribute to the current body of literature by providing a comprehensive review of the advantageous effects of NC incorporation on the aforementioned properties of concrete. A thorough examination of available data was conducted, focusing on the mechanical and thermal characteristics of concrete after the inclusion of NC in the mix design. The findings of this critical review indicate that the incorporation of NC into concrete can reduce building energy consumption and enhance thermal insulation properties. Moreover, the integration of NC in concrete was found to improve various thermal features, including thermal stability, fire resistance, thermal performance, thermal behavior, resistance to thermal cracking, and resistance to thermal degradation. In addition, the inclusion of NC in concrete was observed to decrease thermal conductivity, thereby facilitating effective thermal insulation and resulting in lower energy consumption during heating and cooling periods. Simultaneously, the integration of NC was found to bolster the compressive, flexural, and tensile mechanical properties of concrete. Furthermore, the incorporation of NC into concrete materials has the potential to mitigate negative environmental impacts, such as pollution and poor air quality. This comprehensive review provides valuable insights into the benefits of NC integration in concrete, paving the way for further research and innovative applications in the construction industry. [ABSTRACT FROM AUTHOR]

Silicon nanowires are key anode materials for the fast-paced Li-ion battery technology. However, the thermal properties of lithiated silicon nanowires have not been clarified, particularly with classical interatomic potentials. In this study, we employ a second nearest neighbor modified embedded atom (2NN MEAM) interatomic potential and a non-equilibrium molecular dynamics approach to obtain the thermal conductivity of LiSi (1:1) alloy nanowires. The effects of nanowire length, cross-sectional width, and system temperature are illustrated. The thermal conductivities were in the range of 1.5–3.0 W/(m K) in all the cases showing a suppressed heat transfer in the material. The present study is helpful for thermal management and safety considerations in the anode design of Si nanowires in Li-ion batteries. [ABSTRACT FROM AUTHOR]

S-Graphene, a new allotrope of graphene with two Dirac cones and zero bandgap, exhibits unique and interesting electronic properties due to the robustness of its Dirac cones. This study uses the full tight-binding model to explore the electronic and thermal properties of S-graphene under the influence of external magnetic fields and doping. Linear response theory and Green's function approach based on Kubo formula are employed to investigate the temperature-dependent behavior of electrical and thermal conductivity and Lorenz number. The results indicated that, based on robustness effects, the S-graphene shows different and diverse thermoelectric properties that increase its efficiency significantly. External magnetic fields split the valence and conduction sub-bands of S-graphene and increase its band edges through the Zeeman effect. Increasing the temperature excites charge carriers to the conduction bands, leading to an increase in thermal properties S-graphene with different types. The finding results indicated that in addition to robustness effects, the thermoelectric properties of S-graphene are strongly influenced with the external magnetic field and chemical potential parameters. These parameters increase the thermoelectric properties of S-graphene due to band structure modifications and increasing the density of charge carriers. The findings demonstrate the potential of S-graphene for use in electronic and magnetic devices, opening up new possibilities for further research and development in this field. [ABSTRACT FROM AUTHOR]