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To optimize the comprehensive performance of rare earth (RE) aluminates as thermal/environmental barrier coatings (T/EBCs), we engineered six kinds of novel high-entropy RE aluminate multiphase ceramics with the coexisting garnet and perovskite phases by regulating equivalent ionic radius of RE3+, and the relationship between the microstructure and thermal properties, as well as resistance to CMAS corrosion was investigated in-detail. The findings revealed that the garnet (5RE 0.2) 3 Al 5 O 12 content gradually decreased in multiphase ceramics with the increasing equivalent ionic radius of RE3+. The interaction between garnet and perovskite grains can decrease grain size, which in turn enhanced phonon scattering, thereby leading to the decrease in thermal conductivity. Moreover, the synergistic effect in the different dissolution rates of garnet and perovskite phases can form a dense garnet/apatite barrier layer at corrosion front, thereby contributing to CMAS corrosion resistance. These results provide a robust theoretical foundation for the advancement of next-generation T/EBCs. [ABSTRACT FROM AUTHOR]

Structural damage and shrinkage cracking were exhibited during the pyrolysis of ceramic aerogels prepared by the polymer-derived ceramics (PDCs) route. Herein, the shrinkage of the ceramic precursor during the pyrolysis was offset by utilizing curled molecular chains to store strain in advance. Microspheres composed of curled molecular chains were prepared using polysilazane (PSZ) as a precursor. The microspheres were linked into a three-dimensional skeleton and further fabricated into precursor ceramic microspheres aerogel (PSZ/MCMSA) with shrinkage resistance. The morphology, thermal insulation, and shrinkage resistance properties of the material were tested. The results indicated that PSZ/MCMSA exhibited outstanding thermal insulation and shrinkage resistance properties. The shrinkage of the precursor ceramic microspheres (PSZ/MCMS) was offset by the strain stored through the curled PSZ molecular chains in the PSZ/MCMS. In addition, the microsphere skeleton structural supporting and gas escape channels were formed during the sintering, and the shrinkage resistance of the precursor ceramic aerogel was further enhanced. [ABSTRACT FROM AUTHOR]

Ti 3 SiC 2 MAX phase ceramic has effectively enhanced the oxidation resistance of C/SiC composites. However, there is still a need for a numerical ablation model that can analyze the ablative behavior of 2D C/SiC composites. To address this, an efficient, phenomenological multi-scale ablation model, including the thermal property theoretical model, oxidation, decomposition, and sublimation ablation models, is established for revealing the effect of Ti 3 SiC 2 on the ablation resistance of the 2D C/SiC composite. The ablative behavior is evaluated using the continuous-wave laser with different laser power densities as the heat source and used as a basis for numerical model verification. The results show that the Ti 3 SiC 2 MAX phase ceramic can improve the ablation resistance of the 2D C/SiC composite under different laser power densities. The ablation roughness is reconstructed through the mesoscopic geometry structure and maximum/minimum ablation depth. The numerical model can analyze the effect of the mesoscopic geometry structure parameters on the ablation behavior. The model can provide a predicting method for the quantitative ablative calculation of 2D C/SiC and matrix-modified composites. • An efficient, phenomenological multi-scale ablation model is established. • The ablation resistance mechanism of Ti 3 SiC 2 MAX phase ceramic for the 2D C/SiC composite is revealing. • The mesoscale ablation roughness of 2D C/SiC composites is reconstruction. • The effect of mesoscopic geometry structure parameters on the ablation behavior is analyzed. [ABSTRACT FROM AUTHOR]

This study presents a detailed investigation into the structural, thermal, and radiation shielding properties of a new glass composition, labeled as (50-x)B 2 O 3 + 30TeO 2 + 10Bi 2 O 3 + 10CdO + x Tm 2 O 3 (where x = 0, 1, 2, 3, 4, 5 mol %). Various radiation shielding parameters such as mass attenuation coefficient, linear attenuation coefficient, half-value layer, mean free path, effective atomic number, and absorbed equivalent dose rates for neutrons were determined through experimental measurements. The study also employed theoretical calculations to assess the exposure buildup factor and effective removal cross-section for neutrons. Additionally, the SRIM program was utilized to investigate mass stopping power and projected range for proton and alpha particles. The structural characteristics of the glasses were analyzed using XRD and FT-IR, while thermal properties were examined through Differential Thermal Analysis (DTA). FTIR analysis revealed distinctive bands corresponding to Bi—O, B—O—B, and Te—O bonds. Glass transition temperatures (T g) increased with Tm 2 O 3 content, ranging from 422 °C to 444 °C. The radiation shielding properties of bismuth boro-tellurite glasses showed that a dose of 1.2025 μSv/h emitted from a fast neutron source was absorbed by 35.1574 % in pure glass and 40.0391 % in glass doped with 5 mol% Tm 2 O 3. Incorporating Tm 2 O 3 into the glass matrix significantly improved the shielding and thermal properties, thus enhancing their potential for advanced high-energy radiation absorption. This investigation contributes to a deeper understanding of how Tm 2 O 3 enhances the structural and thermal attributes of these glasses, positioning them as promising materials for radiation shielding applications. [ABSTRACT FROM AUTHOR]

Materials with a thermal expansion coefficient compatible with silicon carbide based ceramic matrix composites and low thermal conductivity at higher temperatures are crucial for developing environmental barrier coatings (EBCs) for aero-engines. Lately, high entropy silicate engineering has been a promising approach to develop optimized EBC materials. The solid solution reaction method was adopted for the fabrication of high entropy multicomponent (Dy 1/5 Er 1/5 Tm 1/5 Yb 1/5 Y 1/5) 2 SiO 5 or (5RE 1/5) 2 SiO 5 monosilicate. Scanning electron microscopy and X-ray diffraction show the homogenous distribution and a single-phase solution of (5RE 1/5) 2 SiO 5 monosilicate. Differential scanning calorimetry testing was done at 1450 °C which shows no exo/endothermic reaction has occurred. The value of the coefficient of thermal expansion (6 ppm/°C) up to temperature 1500 °C and low thermal conductivity values for (5RE 1/5) 2 SiO 5 monosilicate were observed (1.1–1.4 W/m°C) in the temperature range between 25 and 1500 °C. The water vapor corrosion resistance of (5RE 1/5) 2 SiO 5 monosilicate further confirms that the material is suitable for EBC applications due to the synergistic effect of different rare earth radii and stable crystal structure with a negligible weight loss value of 0.0005 mg/cm2 after 150 h corrosion time under 90 % H 2 O and 10 % O 2 at 1300 °C. The results of this work suggest that (5RE 1/5) 2 SiO 5 monosilicate can be used as a promising candidate for environmental barrier coatings. [ABSTRACT FROM AUTHOR]

To improve the oxidation and ablation resistance of SiC f /SiC composites, the as-synthesized ultrafine HfB 2 powder was used as the modification phase to fabricate SiC f /SiC-HfB 2 composites, and their oxidation and ablation behaviors were investigated. Compared with the unmodified SiC f /SiC composites, the oxidation resistance at 800–1500 °C and the ultra-high temperature ablation resistance of SiC f /SiC-HfB 2 composites were significantly improved. After oxidation, a compact compound glass scale consisting of HfO 2 , HfSiO 4 and Si-Hf-O glass was formed, providing the effective oxidation protection. A dual-phase oxide scale composed of HfO 2 skeleton and Si-Hf-O glass was formed after ablation, exhibiting the high viscosity, the significant oxygen-blocking effect and resistance to gas flow scouring. The improved oxidation and ablation resistance of SiC f /SiC-HfB 2 composites could be attributed to the effective protective role of oxygen-blocking scales formed during the oxidation and ablation processes. [ABSTRACT FROM AUTHOR]

Microstructures and thermoelectric properties of porous Ca 3 Co 4 O 9 ceramics were investigated, which were prepared by tert-butanol alcohol (TBA)-based freeze casting method. The honeycomb-like porous Ca 3 Co 4 O 9 ceramic presented an average pore diameter of 2.5 μm and the porosity of 65 %. The excellent low total thermal conductivity of 0.354 W (m K)−1 was obtained along the parallel channel direction, which was attributed to the oriented pores and isolated pores dispersed in ceramics matrix. The compositing thermal conductivity behavior of porous Ca 3 Co 4 O 9 ceramics was jointly regulated by the parallel and Maxwell-Eucken (ME-1) models. The ZT value reached 0.37 at 1073 K. This work provides an effective strategy to improve thermoelectric properties of oxides thermoelectric ceramics, which can complete the decoupling of electrical and thermal properties. [ABSTRACT FROM AUTHOR]

Y 2 O 3 ceramics are increasingly recognized for their excellent vacuum stability and high-temperature chemical stability in the field of functional materials research. However, their poor thermal shock resistance renders them susceptible to spalling and damage during use, thus restricting further applications. To address this issue, the low thermal expansion coefficients of Y 2 SiO 5 materials were leveraged. Through an in situ reaction between SiO 2 and Y 2 O 3 , a Y 2 SiO 5 phase was generated that induced a thermal expansion mismatch with Y 2 O 3 , thereby enhancing the thermal shock resistance of the ceramic. Using Y 2 O 3 fine powder as the primary material, silica sol and nano-SiO 2 were selected as reactive silicon sources to prepare Y 2 O 3 –Y 2 SiO 5 composite ceramics at 1750 °C. The impact of the different silicon sources and Y 2 SiO 5 phase content on the microstructure, mechanical, and thermal properties of the composite ceramics was studied. The results demonstrated that the in situ formation of Y 2 SiO 5 significantly improved the thermal shock resistance of the composite ceramic. Specifically, increasing the SiO 2 content led to a gradual rise in the volume fraction of Y 2 SiO 5 formed between Y 2 O 3 grains, thereby increasing the residual flexural strength and enhancing the hardness and elastic modulus. The low thermal expansion coefficient of Y 2 SiO 5 reduced the overall thermal expansion coefficient of the composite material, thereby improving the thermal shock resistance. Moreover, the thermal expansion coefficient mismatch between the Y 2 O 3 and Y 2 SiO 5 phases induced numerous microcracks within the material, providing thermal stress relief within the microcracks and markedly improving the resistance of the ceramic to thermal shock. [ABSTRACT FROM AUTHOR]

Bi 4 Ti 3- x (Mg 1/2 W 1/2) x O 12 (BTMW100 x) ceramics were synthesized using a direct reaction method combined with a two-step sintering technique. The study systematically investigated the effects of B-site equivalent substitution of (Mg 1/2 W 1/2)4+ on BTMW100 x ceramics. The experimental results indicate that an appropriate amount of (Mg 1/2 W 1/2)4+ doping effectively reduces grain thickness, enhances grain distribution uniformity, and decreases the concentration of oxygen vacancies. Consequently, these modifications lead to improved piezoelectric performance while maintaining a high Curie temperature. Notably, Bi 4 Ti 2.95 (Mg 1/2 W 1/2) 0.05 O 12 (BTMW5) ceramics exhibit excellent piezoelectric properties and thermal stability, with a piezoelectric coefficient of 23 pC/N and a Curie temperature of 683 °C. These findings suggest that BTMW5 ceramics are promising candidates for high-temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

In recent years, phosphors have been used in the field of temperature sensing, which has aroused great interest because of its advantages of quick response, high sensitivity and high accuracy. However, exploring optical thermometers with ultra-high sensitivity remains a challenge. In this work, we have designed and synthesized Sm3+ and Mn4+ co-doped La 3 Mg 2 NbO 9 phosphor for temperature sensing for the first time by utilizing the anomalous thermal quenching property of Sm3+ ions and the sensitive thermal quenching property of Mn4+ ions. Furthermore, the structure, elemental distribution, morphology and optical characteristics of La 3 Mg 2 NbO 9 :Sm3+,Mn4+ were studied in detail. Benefiting from the different responses of the Sm3+ and Mn4+ ions to temperature, the fluorescence intensity ratios of Sm3+ to Mn4+ in La 3 Mg 2 NbO 9 samples show excellent optical thermometry performance in the range of 303–463 K. The maximum absolute sensitivity (S a) and relative sensitivity (S r) values of La 3 Mg 2 NbO 9 :Sm3+,Mn4+ sample reach as high as 0.117 K-1 (@463 K) and 4.48 % K−1 (@303 K), respectively. Furthermore, the maximum of S a is 0.385 K−1 (@463 K) and the maximum of S r is 4.54 % K−1 (@303 K) based on the fluorescence lifetime temperature measurement method. The temperature cyclotron curve of the sample proves that the sample has excellent stability and repeatability in temperature measurement. These results demonstrate that the designed La 3 Mg 2 NbO 9 :Sm3+,Mn4+ phosphor is promising for the field of non-contact optical temperature thermometry. [ABSTRACT FROM AUTHOR]

In the present work, a thermographic procedure to evaluate in-plane thermal diffusivity and parallel finite element method were applied to a metal matrix composite layer. The observed coatings were realized with copper and graphene. Graphene application is more interesting in various fields, but this innovative technology shows various issues of application like the cluster formation that reduces mechanical and physic properties of coating. In this work, the application of graphene can be made with electrodeposition, and a matrix of copper was obtained with subsequent electrodeposition processes. This innovative methodology allows to avoid the issue of cluster formation and increases the amount of graphene in the final layer. In addition, the implementation of multi-coating increases thermal diffusivity by up to 65% obtaining results difficult to reach with a single layer of graphene. In addition, a FEA simulation was carried out to observe the compliance of the numerical method aimed at predicting the thermal properties of the obtained composite. [ABSTRACT FROM AUTHOR]

A coral-like network carbon aerogel was synthesized by introducing acid-modified carbon nanofibers (a-CNF) into phenolic (PR) aerogel through chemical grafting, followed by high-temperature carbonization. The bonding interaction between a-CNF and PR was analyzed by FT-IR spectroscopy. The microstructure of a-CNF/PR composite aerogel (a-CNF/PRA) was studied by SEM and pore structure analysis. The results showed that introducing 5 wt% of a-CNF was most favorable for forming a porous network of a-CNF/PRA. SEM photographs and pore structure analysis indicated that a-CNF/C composite aerogel (a-CNF/CA) developed a stable porous skeletal structure during carbonization. TEM images revealed that the complete porous skeleton consisted of a-CNF encapsulated by carbon layers. The carbonization shrinkage of a-CNF/CA was only 26.53% due to the presence of a-CNF as the skeleton support. Compared to carbon aerogel, a-CNF/CA exhibited lower density (0.072 g cm−3), thermal conductivity (0.0452 W m−1 K−1), and higher compressive strength (up to 3.26 MPa) up to 3.26 MPa than that of carbon aerogel (1.21 MPa). These findings confirmed the excellent mechanical and thermal insulation properties of a-CNF/CA. [ABSTRACT FROM AUTHOR]

TeO 2 single crystals have been widely used in military and civilian fields as an excellent acousto-optic (AO) material. However, due to its significant thermal expansion anisotropy and poor mechanical properties, there is a considerable risk of cracking, which hinders further applications in the AO field. Here we successfully grew a TeO 2 single crystal doped with 2 % Mn4+ ions (TeO 2 :0.02Mn4+). This single crystal demonstrates excellent characteristics, including lower acoustic attenuation (α) and larger refractive index values. In addition, it also possesses a higher AO figure of merit (M 2) of 832 × 10−15 s3/kg than TeO 2 single crystal (∼793 × 10−15 s3/kg). More importantly, the TeO 2 :0.02Mn4+ single crystal demonstrates low thermal expansion anisotropy within a temperature range of up to 450 °C, indicating a greater practical value. The high AO performance may be attributed to manganese ion doping. The doping of Mn increased the refractive indices by enhancing the electronic polarizability and achieved lower acoustic attenuation by improving mechanical properties. Combining the results of elastic modulus and Raman spectroscopy analysis, it is observed that manganese doping optimizes crystal structure disorder, thus improving the issue of thermal expansion anisotropy. These results indicate that this TeO 2 :0.02Mn4+ single crystal has significant potential in designing and manufacturing AO devices. [ABSTRACT FROM AUTHOR]

Induction heating of asphalt concrete has the characteristics of high crack repair efficiency and environmental sustainability. However, the uneven temperature distribution and local overheating obstruct its widespread application. Therefore, this paper conducted a pixel-level quantitative analysis of the temperature distribution characteristics and local overheating phenomenon on both the upper and side surfaces of asphalt concrete with different steel fiber (SF) contents after continuous heating. The temperature distribution was visualized by three-dimensional (3D) heat maps and violin maps. The uniformity of temperature was analyzed by the slope absolute value of the linear fitting results and the ratio of the interquartile range to the range. Results indicated that high SF content accelerated the heating rate of asphalt concrete but decreased the temperature uniformity. Localized overheating caused thermal expansion damage in asphalt mixtures, and the sample with 10% SF had both 304.2°C (maximum) and 79.7°C (minimum) upper surface temperatures at 60 s of heating, with local structural disintegration of the mixture. Higher heating uniformity and faster heating rates were achieved for samples with 6% SF content. The heating rate decreased with increasing heating time. The upper surface of the sample with 8% SF can be heated up the fastest (2.28°C/s). It is recommended that the maximum temperature of the upper surface be controlled during induction heating to avoid thermal damage. This proposal provides a reference for the practical application of induction heating technology. [ABSTRACT FROM AUTHOR]

The objective of this study is to synthesize hollow SiO2 nanospheres (HSNs), and to investigate the effect of varying divinylbenzene (DVB) amounts during synthesis on their morphology and pore structure. Additionally, it seeks to characterize the thermal conductivity of the synthesized HSNs and evaluate the impact of their incorporation on the thermal insulation properties of acrylic coatings. Single‐shell HSNs were synthesized using the Stöber method, which involved hydrolysis‐polycondensation of tetraethyl orthosilicate. The double‐shell HSNs were prepared using a stepwise wrapping synthesis method, with single‐shell HSNs as the core matrix and an appropriate amount of crosslinking agent added. The addition of DVB resulted in different morphologies, shell spacings, and specific surface areas for the double‐shell HSNs. The thermal conductivity of the double‐shell HSNs decreased significantly to as low as 0.0252 W·m1·K−1 with an increase in shell spacing. The shell spacing of double‐shell HSNs had doubled, resulting in a reduction of its thermal conductivity by approximately 18%. When the double‐shell HSN content reached 8%, the thermal conductivity decreased by 85% compared to that of the original acrylate coating. These results indicate that double‐shell HSNs can substantially decrease the thermal conductivity of the matrix material for thermal insulation applications. [ABSTRACT FROM AUTHOR]

Si3N4 ceramics with improved thermal conductivity and mechanical properties were prepared by carbothermal reduction and two‐step sintering. The addition of 2 wt% C led to the development of an intergranular phase YNSiO2 with reduced oxygen content. Notably, setting the pre‐sintering temperature at 1450°C promoted the formation of a rough bimodal morphology within the Si3N4 ceramics. Furthermore, an extended holding period at 1850°C resulted in additional grain growth and the elimination of intergranular phases. The Si3N4 specimens produced at 1450°C for 3 h followed by 1850°C for 8 h, incorporating 2 wt% C, exhibited a notable continuity between Si3N4 grains. The thickness of the grain boundary layer was only about 1 nm, and the N/O atomic ratio of the intergranular phase was measured to be 0.42. Consequently, the resulting thermal conductivity, flexural strength, and fracture toughness of Si3N4 specimens were found to be 101 W·m−1·K−1, 712 ± 29 MPa, and 7.7 ± 0.2 MPa·m1/2, respectively. Compared with samples without C additive and directly sintered at 1850°C for 8 h, the Si3N4 specimens produced in this work showed a significant increase of more than 50% in thermal conductivity and about 17% in fracture toughness. [ABSTRACT FROM AUTHOR]

The development and commercialization of aerospace vehicles have posed significant challenges to the performance requirements for the corresponding materials. To meet these challenges, ceramic matrix composites (CMCs) have been developed and are widely used in the aerospace industry. However, their stability under extreme environmental conditions still needs to be improved. In this review, some properties of zirconium carbide (ZrC), which are related to extreme environmental applications of CMC are discussed first. Then, the effect of ZrC on the properties of CMC is comprehensively reviewed. ZrC can be introduced into the matrix and coated on the surface to increase the ablation resistance. The protection mechanisms of ZrC addition to CMCs, and the improvement in ZrC ablation resistance are explained. In addition, some perspectives on future developments are given. [ABSTRACT FROM AUTHOR]

The increase in operating temperature contributes to improving the performance and fuel utilization efficiency of gas turbines. However, it also places thermal barrier coatings (TBCs) in a more demanding working environment, requiring higher sintering resistance and better mechanical properties. In the present study, HfO2 was introduced into the dual‐phase LaYbZr2O7 system as a doping oxide to form the LaYb(HfxZr1−x)2O7 system. The research concentrated on its phase composition, mechanical properties, and thermophysical properties. The results show that substituting Hf for Zr does not alter the dual‐phase structure of the system. The mutual inhibition between the two phases and the inherent material‐binding capability of Hf further reduce the grain size compared to pure LYZO. Additionally, the presence of Hf reduces the tendency of Frenkel defect formation and cation migration frequency, effectively inhibiting ion diffusion and thereby suppressing the densification and shrinkage trends of the material. The system retains relatively high hardness, fracture toughness, and low elastic modulus of the LYZO matrix, with a decrease in thermal conductivity and an increase in infrared reflectivity. These results suggest that Hf doping enhances the sintering resistance of LYZO material, making them promising for high‐temperature TBCs. Our study presents a viable approach to enhance the sintering resistance of LYZO, and this methodology can be extrapolated to other rare‐earth zirconates. [ABSTRACT FROM AUTHOR]

Er3+‐doped fluoride glass and fiber have been widely used in multiple fields such as mid‐infrared laser, visible laser, and amplifier. However, there is no unified conclusion on the thermal and optical properties with respect to varying concentrations of Er3+ doping. Furthermore, this is a paucity of systematic guidance on the preparation of Er3+‐doped fluoride glass and fiber. In this study, fluorozirconate fiberglass with Er3+ doping is systematically examined. Additionally, a preliminary explanation of the evolutionary behavior of glass devitrification, thermal properties, and fluorescence properties is provided. Energy transition models were built for 1.5 and 2.7 µm emissions in Er3+‐doped fluorozirconate at room temperature. Moreover, a suitable doping concentration is proposed based on the evolutionary behavior of thermal and optical properties. In this study, guidance on appropriate Er3+ doping concentration levels in fluorozirconate glass is provided and potential applications are explored. [ABSTRACT FROM AUTHOR]

The crystallization thermal stability plays an essential role in affecting thermal stress of glass-ceramic sealant for long-term planar-type solid oxide fuel cells (SOFC) to prevent fuel leakage during operation. Due to the lack of systematic research on regulating the stable performance of glass-based sealant with the working time at operation temperature, herein, the effect of MgO on crystallization kinetics, phase stability, and thermal and mechanical properties of MgO–BaO–CaO–Al 2 O 3 –B 2 O 3 –SiO 2 (MBCABS) glass-ceramic has been firstly analyzed at heat-treatment of 750 °C with working time of 1∼1000h in this work. Subsequently, the relationship evolution of crystallization thermal stability-coefficient of thermal expansion (CTE) match-thermal stress was established by Finite Element Method (FEM). The main reasons for the decrease of CTE of MBCABS glass-ceramics with low-content MgO are the precipitation of hexagonal BaAl 2 Si 2 O 8 phase and the transformation of hexagonal BaAl 2 Si 2 O 8 to low-CTE monoclinic BaAl 2 Si 2 O 8 phase, bring about that the Von Mises thermal stress of sealant itself and interface having tripled at 1000h (more than 200 MPa) according to FEM simulation results. The thermal stable and high-CTE BaMgSiO 4 , Ba 8 Mg 16 Si 16 O 56 , and BaCa 2 Mg(SiO 4) 2 phases crystallized in MBCABS glass-ceramics with high-content MgO, therefore the maximum stress at all time parameters was below 100 MPa for 1∼1000h. This study was useful for identifying the optimal phase option and CTE matching of glass-based sealant for efficient and stable long-term operation of solid oxide fuel cells. [ABSTRACT FROM AUTHOR]

Cordierite-mullite composite ceramics were prepared by solid-state method using Panzhihua low-grade Ti-rich clay, talc, and alumina. Influences of cordierite/mullite ratio, sintering temperature, and the chemical composition of clay on the phase composition, microstructure, physical properties, and thermal properties were investigated in detail. The results showed that the impurity oxides inside the Ti-rich clay had a great ability of forming liquid. Above 1300 °C, the reaction between TiO 2 of the clay and Al 2 O 3 produced stable Al 2 TiO 5 , which was conducive to decreasing the coefficient of thermal expansion (CTE). At 1300–1350 °C, the secondary mullitization caused the volumetric expansion, decreasing the bending strength and increasing the CTE. The optimum ratio of cordierite to mullite ranged from 90:10 to 80:20, and the sample fired at 1400 °C exhibited the lowest water absorption and porosity (0.64 % and 1.56 %, respectively), optimal bulk density, and bending strength (2.59 g cm−3 and 87.79 MPa), as well as better CTE, thermal conductivity, and thermal storage density (2.91 × 10−6 °C−1, 4.11 W/(m⋅K) (30 °C), and 1181 kJ kg−1, respectively). Compared with the reported values of cordierite-based thermal storage ceramics prepared by using the high-grade clay or minerals, the obtained samples showed the advantages such as lower costs for raw materials, higher bending strength, higher thermal conductivity (1.63–2 times higher), low CTE, and high thermal storage density. This study demonstrated that the low-grade Ti/Fe-rich clay has excellent cost-effective potential for the preparation of thermal storage ceramics. [ABSTRACT FROM AUTHOR]

In the domain of personal thermal protection, there is a growing demand for lightweight and efficient ceramic thermal insulation materials. However, conventional ceramic membranes face challenges such as brittleness, structural collapse, and pulverization, hindering their practical application. To address this issue, aluminum hydroxide-enhanced silica-zirconia ceramic membranes (SZ@ANFMs) have been successfully fabricated using electrospinning followed by subsequent calcination processes, and their properties have been comprehensively evaluated. The results demonstrate that SZ@ANFMs exhibit outstanding high-temperature resistance under an alcohol lamp, along with an extremely low thermal conductivity (only 0.041 W/m·K), excellent tensile strength (2.3 MPa), and flexible characteristics. This makes them highly promising in the domain of personal thermal protection. The study builds upon existing research in lightweight and efficient thermal insulation materials, offering improvements and robust support for the further development of personal thermal protection technology. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical, thermal, and water absorption properties of high-density polyethylene (HDPE) composites filled with barley straw and varying amounts of waste rubber. The research aims to develop sustainable materials that repurpose agricultural and industrial waste while addressing resource scarcity and waste management challenges. Composites were prepared using a twin-rotor mixer and hydraulic press, with waste rubber content varying from 0 to 20 wt%. Mechanical properties were evaluated through tensile testing, thermal behavior was analyzed using TGA, DTG, and DSC, and long-term water absorption was measured. Results show that increasing waste rubber content from 0 to 20% led to a decrease in tensile strength (11.3 to 8.9 MPa) and tensile modulus (1760 to 790 MPa), while relative extension increased (2.4–5.9%). Thermal analysis revealed a slight reduction in onset degradation temperature (270 °C to 240 °C) and increased char residue (8–18%) with higher rubber content. Water absorption decreased significantly, from 12 to 13% to 6–7% after 600 h of immersion, as waste rubber content increased. These findings demonstrate that incorporating waste rubber into HDPE/barley straw composites results in materials with enhanced flexibility and water resistance at the cost of some strength and stiffness. In conclusion, the results of this study offer a clear pathway for the development of sustainable polymer composites that have broad potential applications across industries like construction, marine infrastructure, automotive, and packaging. By replacing traditional, resource-intensive materials with eco-friendly alternatives, these composites not only provide functional benefits but also support global efforts toward sustainable development and environmental conservation. [ABSTRACT FROM AUTHOR]

Plumes are considered to play an important role in the origin of the solar wind. However, an understanding of their thermodynamic evolution is not complete. Here, we perform a detailed study of a plume inside a coronal hole throughout its lifetime, using the observations from the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager. We find that the plume's formation is preceded by frequent occurrences of small-scale jets and jetlets at its base, leading to the gradual development of plume haze. The plume rapidly developed within the first 6 hr into its well-known morphology. Light curves from all extreme ultraviolet channels exhibit a similar profile, suggesting its multithermal nature and intensity modulation over its lifespan. Moreover, the photospheric magnetic field dynamics at the plume's base are highly correlated with its light curve in 171 Å. We calculate outflow velocities, observed prominently in the 171 Å passband and mildly in the 193 and 211 Å passbands, with median speeds lower in higher temperature bands but occasionally comparable to the respective sound speeds. When data are averaged over larger spatial scales, the plume appears isothermal along its length, with constant temperature throughout its lifetime. However, an analysis of the differential emission measure at full resolution reveals the presence of higher-temperature plasma, indicating internal temperature structures within the plume. These results provide new insights into the formation, dynamics, and thermal properties of coronal plumes, placing tighter constraints on models to understand their thermodynamic evolution and potential role in the solar wind. [ABSTRACT FROM AUTHOR]

This work created a fireproof sandwich structure in which the face sheets were made of expanded vermiculite and expanded perlite‐filled geopolymer composites and embedded basalt fiber mats and the core material was rock wool in designing the lightweight and cost‐effective fire‐resistant structure for steel bridges with excellent retardant and heat‐insulating performance. The effects of adding 5%, 10%, 15%, and 20% expanded vermiculite and expanded perlite to the geopolymer on mechanical properties and the thermal conductivity were investigated to obtain the optimized material mixtures for preparing the face‐sheets material of the sandwich panel. Then, the fireproof sandwich structures were fabricated and exposed to 800°C for 3 h to study the structural integrity, backfire side temperature, and mass loss ratio. The results indicated that adding 10 wt% expanded vermiculite and 10 wt% expanded perlite to the geopolymer achieved the retention of compressive strength of 66.5% after being exposed to 800°C, and the geopolymer mixtures showed a low thermal conductivity of 0.1942 W/(mK). The TOPSIS evaluation analysis reveals that the proposed fireproof sandwich panel had the highest integrated performance considering the structural weight, insulation properties, and cost. The findings of this work may provide some insights into fireproof and insulating applications in bridge engineering. [ABSTRACT FROM AUTHOR]

Far infrared radiation (FIR) within the wavelength range of 4–14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding. [ABSTRACT FROM AUTHOR]

A high‐entropy rare‐earth disilicate (Er0.25Y0.25Ho0.25Yb0.25)2Si2O7 (hereinafter referred to as (EYHY)2Si2O7) ceramic was synthesized by a heat treatment process combined with spark plasma sintering. According to the experimental results, (EYHY)2Si2O7 presents good phase stability and low thermal conductivity ([1.48–2.35] W∙m−1∙K−1) from room temperature to 1200°C. Its coefficient of thermal expansion is (3.89–5.32) × 10−6 K−1 from 200 to 1400°C, similar to SiC‐based materials ([4.5–5.5] × 10−6 K−1). Due to the multiple doping effects, (EYHY)2Si2O7 exhibits outstanding corrosion resistance performance in water‐vapor corrosion tests. Its weight loss is 1.79 mg/cm2 after corrosion at 1600°C for 30 h in the presence of 50% H2O‐50% O2, which is lower than the corresponding four single components Re2Si2O7 (Er2Si2O7, Y2Si2O7, Ho2Si2O7, and Yb2Si2O7) under the same conditions. Therefore, high‐entropy (EYHY)2Si2O7 ceramics are regarded as potential environmental barrier coatings materials for SiC ceramic matrix composites. [ABSTRACT FROM AUTHOR]

The present research article demonstrates the dispersion of boehmite (BHM) nanoparticles into sericin (SER) from silk industry waste with polyvinyl alcohol (PVA) to enhance the optical, mechanical, thermal and electrical characteristics of PVA/SER blend nanocomposites prepared by a simple green synthesis. Techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV visible spectroscopy, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out for the characterization of the prepared composites. XRD revealed the increased crystallinity of the polymer blend by the reinforcement of BHM. The existence of intermolecular interactions in the blend composite was confirmed by FTIR and UV spectroscopy. The optical bandgap energy of the biopolymer blend decreases with the inclusion of BHM. The SEM and HR-TEM confirmed the homogeneous dispersion of BHM in the blend at 5 wt% loading. The glass transition temperature and thermal stability of the blend nanocomposites were significantly improved by the inclusion of BHM was deduced from DSC and TGA. The dielectric constant and AC conductivity were remarkably increased with the reinforcement of nanoparticles. The activation energy obtained from AC conductivity decreased with temperature. The mechanical properties of the blend nanocomposites (hardness, tensile strength and Young's modulus) were greatly increased in presence of BHM. The 5 wt% sample has the highest tensile strength, Young's modulus, dielectric constant, AC conductivity and optical properties, allowing it to be used to make optoelectronic devices with better charge-storing capacity and flexible-type electrochemical gadgets. [ABSTRACT FROM AUTHOR]

In this study, composite phase change materials (CPCMs) comprising hexadecylamine (HDA) (C 16 H 35 N), disodium hydrogen phosphate dodecahydrate (DHPD) (Na 2 HPO 4 ·12H 2 O), and expanded graphite (EG) were prepared using the demulsification method. These CPCMs exhibit high latent heat and stable thermal properties. This approach effectively mitigates the issues of substantial supercooling and poor thermal conductivity commonly associated with DHPD and HDA. Additionally, the inclusion of EG imparts superior morphological stability to the CPCMs. The HDA/DHPD/EG CPCMs demonstrated robust thermal and morphological stability at temperatures below 100 °C. Their latent heat reached up to 221 J/g and remained stable at this value even after 50 cold-heat cycles, thereby indicating excellent cycling stability. When EG was incorporated at 2 wt%, the thermal conductivity of the HDA/DHPD/EG CPCMs increased to 0.751 W/(m·K), indicating that the three-dimensional network structure of EG facilitates heat conduction and offers exceptional photothermal conversion capabilities, with a photothermal conversion efficiency of up to 97.1 %. The aforementioned results highlight the promising potential of the prepared CPCMs for applications in low-temperature waste heat recovery. [ABSTRACT FROM AUTHOR]

One of the challenges facing our current and future generations is the effective management of energy and its acquisition through more sustainable means. One solution is using materials capable of generating energy from temperature differences. Construction materials could be the answer, as they are already integrated into structures and have good thermoelectric properties. Geopolymers, emerge as a promising candidate due to their enhanced sustainability compared to alternative materials. Our research explored the use of geopolymers for electricity generation from heat. To minimize the usage of kaolin, we incorporated 50 % of two mining residues obtained from old mines located in Portugal. This approach optimizes the utilization of mineral resources and mitigates the environmental impact. Various methods were used to characterize this material, such as X-ray diffraction, simple compressive strength tests and evaluation of thermoelectric properties, such as the Seebeck coefficient and figure of merit. The geopolymers tested exhibit semiconductor characteristics, demonstrating poor heat conduction due to their low thermal conductivity. Regarding thermoelectric properties, these materials display N-type behavior, with a Seebeck Coefficient between −643 μV/°C and −2760 μV/°C. These findings underscore the advantages of utilizing this sustainable material for the widespread implementation of energy management in buildings on a large scale. [ABSTRACT FROM AUTHOR]

BiCuSeO, an oxide thermoelectric material with a superlattice structure, presents the advantages of affordability, low toxicity, and environmental friendliness. However, its intrinsic low electrical conductivity has impeded its possible applications. To address this challenge, we put tiny PbZr 0.52 Ti 0.48 O 3 (PZT) with varying weight percentages (x = 0, 5, 7, 9, 11) into BiCuSeO (BCSO) to fabricate thermoelectric nanocomposites. Through the spark plasma sintering process, PZT particles underwent in-situ decomposition, generating nano-sized second phases such as PbO 2 , TiO 2 , and PbZrO 3 , which are homogenously distributed within BCSO matrix (validated by XRD and TEM). The introduced PbO 2 , TiO 2 , and PbZrO 3 second phases served a dual purpose: inhibiting the grain growth of BCSO and introducing additional nano-grain boundaries. This resulted in more effective phonon scattering sites, thereby reducing lattice thermal conductivity. Simultaneously, the Pb element derived from PZT decomposition was doped into the Bi site of the BCSO matrix, causing a reduction in the band gap of BCSO from 0.49 eV to 0.388 eV and a significant increase in carrier concentration. Consequently, this doping enhanced the electrical conductivity of BCSO-based composites, with the composite with 11 wt% PZT additive amount exhibiting a remarkable 318-fold increase, reaching 550 S/cm compared to pristine BCSO. Notably, the composite with 7 wt% PZT additive amount achieved an exceptionally low lattice thermal conductivity of 0.333 W m−1 K−1 at 823 K. Through the synergistic optimization of electrical and thermal transport properties, the BCSO-based composite with 7 wt% PZT additive amount obtained a ZT value of ∼0.9 at 873 K, representing a 2.45-fold increase compared to pristine BiCuSeO. This straightforward method presents a cost-effective and scalable approach to enhance the thermoelectric performance of various materials, opening new avenues for potential commercial applications. [ABSTRACT FROM AUTHOR]

Investigating how the thermal transport properties of iron change under extremely high pressure and temperature conditions, such as those found in the Earth's core, is a major experimental challenge. Over the past decade, there has been a great deal of discussion and debate surrounding the thermal conductivity of the iron-based Earth's core and its thermal evolution. One reason for this may be the variability in the experimentally obtained thermal conductivity of iron at high pressures and temperatures. In this study, we present the experimental results of measuring the thermal conductivity of hexagonal-closed-pack (hcp) iron over a wide pressure-temperature range up to 176 GPa and 2900 K using the pulsed light heating thermoreflectance technique in a laser-heated diamond anvil cell. Our findings indicate that the temperature derivative of the thermal conductivity of hcp iron undergoes a change from negative to positive above 74 GPa, potentially making hcp iron highly conductive at conditions similar to those observed in the Earth's core. This observation represents a notable example of a phenomenon where pressure appears to influence the sign of the temperature derivative of the thermal conductivity of an isostructural metal. [ABSTRACT FROM AUTHOR]

This work presents the exploration of a promising thermal environmental barrier coating material by engineering the compositions of (Ho1/4Er1/4Dy1/4X1/4)2Si2O7 high‐entropy rare‐earth disilicates (HERED‐X, X = Gd, Tm, Yb, Lu, Sc, Y). Among all the samples, the as‐fabricated HERED‐Gd samples possess the best CMAS corrosion resistance with a corrosion rate of 8.2 ± 0.14 µm h−1 at 1673 K, which is attributed to the synergistic effects of high chemical reactivity of HERED‐Gd and good stability of the formed apatite in CMAS melt. Moreover, they demonstrate a matched coefficient of thermal expansion (4.6 × 10−6 K−1) with SiCf/SiC composites (4.5–5.5 × 10−6 K−1) and a low thermal conductivity (1.89 W m−1 K−1 at room temperature). [ABSTRACT FROM AUTHOR]

Banana fruits are rich in starch, and unripe banana flour is considered a beneficial ingredient in the food industry because it has high levels of resistant starch, which significantly aids in promoting gut health and regulating blood sugar and lipid levels. However, the associations between banana cultivars with various genotypes cultivated globally and their resistant starch properties remain unclear. Herein, we investigated resistant starches from 16 banana cultivars covering three genome groups (ABB, AAB, and AAA) in order to reveal the differences and similarities among these cultivars. The results showed that there was a genotype-specific pattern in banana resistant starch (BRS) degradation. The AAA genome BRS exhibited a high degree of resistant starch degradation. The genotypes of the banana cultivars also impacted the granular morphology of the resistant starch. The ABB and AAB genome BRS were more conducive to forming resistant starch. The BRS samples from the three genome groups displayed either B-type or C-type structures. Even within the same genome group, the BRS samples exhibited differences in thermal and pasting properties. These findings reveal the impact of genotypes on BRS content and characteristics, providing a basis for future breeding and resistant starch utilization. [ABSTRACT FROM AUTHOR]

This work investigates the application of poly(3,4‐ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) with polyethylene oxide (PEO) in lithium batteries (LIBs). This composite film comprising PEDOT:PSS and PEO was 3D printed onto a carbon nanofiber (CNF) substrate to serve as a layer between the polypropylene (PP) separator and the lithium anode in LIBs. The resulting CNF‐PEDOT:PSS‐PEO film exhibited superior mechanical and thermal properties compared to conventional PP separators. Mechanical tests revealed a high Young's modulus and puncture strength for the composite film. Thermal stability tests indicated that the CNF‐PEDOT:PSS‐PEO film remained stable at higher temperatures compared to the commercial PP separator, and combustion tests confirmed its superior fire‐resistance properties. In terms of conductivity, the composite film maintained comparable ionic conductivity to the commercial PP separator. Electrochemical tests demonstrated that LIBs incorporating the CNF‐PEDOT:PSS‐PEO film exhibited slight improvement in cycling performance, with a 7.9 % increase in long‐term cycling capacity compared to LIBs using only the commercial PP separator. These findings indicate that the developed CNF‐PEDOT:PSS‐PEO composite film holds promise to improve safety, while maintaining the electrochemical performance of LIBs by reducing dendrite formation and enhancing thermal stability. [ABSTRACT FROM AUTHOR]

Whey protein hydrolysates, derived from enzymatic hydrolysis of whey protein isolates or concentrates, offer enhanced bioavailability and solubility compared to intact whey protein. In this study, whey protein hydrolysates (WPHs) having different hydrolysis degrees (5%, 10%, and 15%) were produced and muffin cakes were enriched with the addition of WPHs. In general, the addition of WPHs showed a significant effect on oil and protein content while the emulsion activity was improved with the increased hydrolysis degree (HD). The degree of hydrolysis increment resulted in a significant increase in both antioxidant power and antiradical activity of the WPHs. Ferric‐reducing antioxidant power and ABTS radical scavenging activity ranged between 18.83–87.27 mg TE/100 g and 211.8–5063.1 mg TE/100 g, respectively. The highest FRAP and ABTS values were recorded for the 15% HD while the lowest was for the native whey protein isolate (WPI). The induction periods giving a clear information for the oxidative stability were 1593 min for the control muffins, and it was 1654 for the muffin added with WPI. Rheological data revealed that all cake batter samples including WPHs showed viscoelastic behavior. WPHs could be efficiently used in muffin formulation to increase the biofunctional effects of the final products. [ABSTRACT FROM AUTHOR]

In recent years, the implementation of CO2 capture systems has increased. To reduce the costs and the footprint of the processes, different industrial wastes are successfully proposed for CO2 capture, such as gypsum from desulfurization units. This gypsum undergoes an aqueous carbonation process for CO2 capture, producing an added-value solid material that can be valorized. In this work, panels have been manufactured with a replacement of (5 and 20%) commercial gypsum and all the compositions kept the water/solid ratio constant (0.45). The density, surface hardness, resistance to compression, bending, and fire resistance of 2 cm thick panels have been determined. The addition of the waste after the CO2 capture diminishes the density and mechanical strength. However, it fulfills the requirements of the different European regulations and diminishes 56% of the thermal conductivity when 20%wt of waste is used. Although the CO2 waste is decomposed endothermically at 650 °C, the fire resistance decreases by 18% when 20%wt. is added, which allows us to establish that these wastes can be used in fire-resistant panels. An environmental life cycle assessment was conducted by analyzing a recycling case in Spain. The results indicate that the material with CO2 capture waste offers no environmental advantage over gypsum unless the production plant is located within 200 km of the waste source, with transportation being the key factor. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive review of the advancements in the use of Date Palm Fiber (DPF) reinforced composites, highlighting their mechanical, thermal, and morphological properties and the enhancements achieved through various modification techniques. Date palm fibers, a sustainable and biodegradable resource, have garnered significant interest due to their potential in reducing environmental impact across several key industries, including building and construction, automotive, and packaging. The review discusses the effects of hybrid approaches and physical and chemical treatments on the mechanical properties of DPF composites, demonstrating improvements in tensile strength, elasticity, and flexural strength through optimized fiber‐matrix bonding and reduced moisture absorption. Thermal behavior analyses through Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), and thermal conductivity underscore the composites' suitability for applications requiring high thermal stability and conductivity for insulation applications. Morphological studies reveal that surface‐treated fibers integrate more effectively with various polymeric matrices, leading to enhanced composite performance. The practical applications of DPF composites are explored, emphasizing their role in promoting sustainable manufacturing practices. Challenges such as scalability, cost‐efficiency, and performance consistency are addressed, alongside future perspectives that suggest a promising direction for further research and technological development in the field of natural fiber composites. This review aims to solidify the foundation for ongoing advancements and increase the adoption of DPF composites in commercial applications. [ABSTRACT FROM AUTHOR]

This study investigates the pressure-dependent thermal and mechanical properties of solid bromine through density functional theory (DFT) calculations used in conjunction with the quasi-harmonic approximation (QHA). At ambient pressure, bromine crystallizes as a molecular crystal of Cmca symmetry. Previous studies have indicated that upon compression, this polymorph should undergo a bandgap closure at 80 GPa followed by a phase transition to a nonmolecular phase at 90 GPa. By employing QHA, we model the lattice vibrations and calculate the free energy, thermal expansion, and specific heat capacities of solid molecular bromine over a temperature range from 0 to 1000 K and pressures up to 90 GPa. Furthermore, mechanical properties such as bulk modulus and elastic constants are also analyzed. The results reveal the significant impact that pressure has on the thermal properties, mechanical stability, and dynamical stability of a molecular crystal. These findings contribute to a deeper understanding of such systems under extreme conditions, potentially guiding future experimental and theoretical investigations. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis, characterization, and application of four ionic liquids (ILs), three of which are being reported for the first time, with unique thermal properties and diverse anion-cation combinations, specifically in the context of epoxy resin polymerization. 1-3-Didodecylimidazolium dicyanamide (dDDIM DCA), 1-3-Didodecylimidazolium docusate (dDDIM DOSS), 1-ethyl-3-methylimidazolium dicyanamide (EMIM DCA), and 1-ethyl-3-methylimidazolium docusate (EMIM DOSS) were used to prepare six different mixtures with the same cation and with varying concentrations of DCA components, which is the main factor of an efficient polymerization, while the other component is intended to modify the properties of the cured resin. Mixtures based on EMIM cation demonstrated increased enthalpy and lower onset polymerization temperatures, indicating more efficient curing processes. The hardness of cured epoxy resins can be adjusted by altering the curing temperature and IL composition, with EMIM DCA and EMIM DOSS mixtures displaying high Shore A hardness, suitable for durable surface applications. In contrast, mixtures with higher dDDIM DCA proportions offered a balance between rigidity and flexibility, ideal for applications requiring both mechanical strength and elasticity. [ABSTRACT FROM AUTHOR]

Hybrid carbon nanotube (CNT) sheets were fabricated by mixing CNTs with silver nanowires (AgNWs) and MXene to study their electromagnetic-interference (EMI)-shielding properties. CNT/AgNW and CNT/MXene hybrid sheets were produced by ultrasonic homogenization and vacuum filtration, resulting in free-standing CNT sheets. Three different weight ratios of AgNW and MXene were added to the CNT dispersions to produce hybrid CNT sheets. Microstructure characterization was performed using scanning electron microscopy, and the Wiedemann–Franz law was used to characterize transport properties. The resulting hybrid sheets exhibited improved electrical conductivity, thermal conductivity, and EMI-shielding effectiveness compared to pristine CNT sheets. X-band EMI-shielding effectiveness improved by over 200%, while electrical conductivity improved by more than 1500% in the hybrid sheets due to a higher charge-carrier density and synergistic effects between nanomaterials. The addition of AgNW to CNT sheets resulted in a large improvement in electrical conductivity and EMI shielding; however, this may also result in increased weight and sample thickness. Similarly, the addition of MXene to CNT sheets may result in an increase in weight due to the presence of the denser MXene flakes. [ABSTRACT FROM AUTHOR]

This article explores the important, and yet often overlooked, solid-state structures of selected bioaromatic compounds commonly found in lignin hydrogenolysis oil, a renewable bio-oil that holds great promise to substitute fossil-based aromatic molecules in a wide range of chemical and material industrial applications. At first, single-crystal X-ray diffraction (SCXRD) was applied to the lignin model compounds, dihydroconiferyl alcohol, propyl guaiacol, and eugenol dimers, in order to elucidate the fundamental molecular interactions present in such small lignin-derived polyols. Then, considering the potential use of these lignin-derived molecules as building blocks for polymer applications, structural analysis was also performed for two chemically modified model compounds, i.e., the methylene-bridging propyl-guaiacol dimer and propyl guaiacol and eugenol glycidyl ethers, which can be used as precursors in phenolic and epoxy resins, respectively, thus providing additional information on how the molecular packing is altered following chemical modifications. In addition to the expected H-bonding interactions, other interactions such as π–π stacking and C–H∙∙∙π were observed. This resulted in unexpected trends in the tendencies towards the crystallization of lignin compounds. This was further explored with the aid of DSC analysis and CLP intermolecular energy calculations, where the relationship between the major interactions observed in all the SCXRD solid-state structures and their physico-chemical properties were evaluated alongside other non-crystallizable lignin model compounds. Beyond lignin model compounds, our findings could also provide important insights into the solid-state structure and the molecular organization of more complex lignin fragments, paving the way to the more efficient design of lignin-based materials with improved properties for industrial applications or improving downstream processing of lignin oils in biorefining processes, such as in enhancing the separation and isolation of specific bioaromatic compounds). [ABSTRACT FROM AUTHOR]

Optically transparent polyimide (PI) films with good atomic oxygen (AO) resistance have been paid extensive attention as thermal controls, optical substrates for solar cells or other components for low Earth orbit (LEO) space applications. However, for common PI films, it is usually quite difficult to achieve both high optical transparency and AO resistance and maintain the intrinsic thermal stability of the PI films at the same time. In the current work, we aimed to achieve the target by using the copolymerization methodology using the fluorinated dianhydride 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride (6FCDA), the fluorinated diamine 2,2-bis [4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) and the polyhedral oligomeric silsesquioxane (POSS)-containing diamine N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) as the starting materials. The fluoro-containing monomers were used to endow the PI films with good optical and thermal properties, while the silicon-containing monomer was used to improve the AO resistance of the afforded PI films. Thus, the 6FCDA-based PI copolymers, including 6FCPI-1, 6FCPI-2 and 6FCPI-3, were prepared using a two-step chemical imidization procedure, respectively. For comparison, the analogous PIs, including 6FPI-1, 6FPI-2 and 6FPI-3, were correspondingly developed according to the same procedure except that 6FCDA was replaced by 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Two referenced PI homopolymers were prepared from BDAF and 6FDA (PI-ref1) and 6FCDA (PI-ref2), respectively. The experimental results indicated that a good balance among thermal stability, optical transparency, and AO resistance was achieved by the 6FCDA-PI films. For example, the 6FCDA-PI films exhibited good thermal stability with glass transition temperatures (Tg) up to 297.3 °C, good optical transparency with an optical transmittance at a wavelength of 450 nm (T450) higher than 62% and good AO resistance with the erosion yield (Ey) as low as 1.7 × 10−25 cm3/atom at an AO irradiation fluence of 5.0 × 1020 atoms/cm2. The developed 6FCDA-PI films might find various applications in aerospace as solar sails, thermal control blankets, optical components and other functional materials. [ABSTRACT FROM AUTHOR]

Thermoplastic polyimides (TPIs) are promising lightweight materials for replacing metal components in aerospace, rocketry, and automotive industries. Key TPI attributes include low density, thermal stability, mechanical strength, inherent flame retardancy, and intrinsic fluorescence under UV light. The application of advanced manufacturing techniques, especially 3D printing, could significantly broaden the use of TPIs; however, challenges in melt-processing this class of polymer represent a barrier. This study explored the processability, 3D-printing and hence mechanical, and fluorescence properties of TPI coupons, demonstrating their suitability for advanced 3D-printing applications. Moreover, the study successfully 3D-printed a functional impeller for an overhead stirrer, effectively replacing its metallic counterpart. Defects were shown to be readily detectable under UV light. A thorough analysis of TPI processing examining its rheological, morphological, and thermal properties is presented. Extruded TPI filaments were 3D-printed into test coupons with different infill geometries to examine the effect of tool path on mechanical performance. The fluorescence properties of the 3D-printed TPI coupons were evaluated to highlight their potential to produce intricately shaped thermally stable, fluorescence-based sensors. [ABSTRACT FROM AUTHOR]

Nowadays, the demand for food packaging that maintains the safety and quality of products has become one of the leading challenges. It can be solved by developing functional materials based on biodegradable polymers, such as poly(lactic acid) (PLA). In order to develop PLA-based functional materials with antibacterial activity, silver nanoparticles (AgNPs) were introduced. In the present study, AgNPs stabilized by a copolymer of ethylene and maleic acid were used. Under the joint action of shear deformations and high temperature, the biocomposites of PLA with poly(ethylene glycol) and AgNPs were produced. Their mechanical and thermal characteristics, water absorption, and structure were investigated using modern methods (DSC, FTIR, Raman spectroscopy, SEM). The effect of AgNP concentration on the characteristics of PLA-based biocomposites was detected. Based on the results of antibacterial activity tests (against Gram-positive and Gram-negative bacteria, along with yeast) it is assumed that these systems have potential as materials for extending the storage of food products. At the same time, PLA–PEG biocomposites with AgNPs possess biodegradability. [ABSTRACT FROM AUTHOR]

The influence of Si content (0.1–0.8 wt.%) on the development of precipitation microstructures and the resultant mechanical and creep properties during thermal exposure, up to 1000 h at 300 °C, in Al–Cu 224 cast alloys, was systematically investigated. The room and elevated temperature yield strength (YS) increased with increasing Si content under the T7 condition, which was attributed to the fact that the Si promoted the precipitation of fine θ′. However, Si increased the coarsening of θ′ during thermal exposure at 300 °C, and the alloys with low Si exhibited a higher YS and creep resistance at elevated temperatures than high Si alloys. The mechanical strength and creep resistance were mainly controlled by the precipitation strengthening of the predominant θ′ phase. Because of the high mechanical strength and creep resistance of the 0.1Si alloy during long-term thermal exposure, the Si level in Al–Cu alloys should be maintained at a low level of 0.1 wt.% for high-temperature applications. The strengthening mechanisms were quantitatively analyzed, based on the characteristics of the precipitate. The predicted YS values under different exposure conditions agreed well with the experimentally measured values. [ABSTRACT FROM AUTHOR]

This study uses an extrusion process to formulate blends based on recycled high-density and high-molecular-weight polyethylene (recHDPE, recHMWPE) for the manufacture of rainwater drainage pipes. The main objective of this project is to investigate the effects of incorporating graphene on the mechanical, thermal, and stress-cracking resistance properties of the recycled HDPE and HMWPE blends. Also, it aims to demonstrate that the addition of graphene may enable the use of different recycled polymers without compromising their properties. The effects of adding two amounts of graphene (0.5 and 1%) to recycled blends on the tensile and flexion properties, stress crack resistance (SCR) (using a notched crack ligament stress (NCLS) test), thermal behavior (using a differential scanning calorimeter (DSC) and a rheological plastometer) were investigated. The experimental results showed a significative enhancement when adding graphene in the SCR, some tensile properties (elongation at break and tensile strength), and flexural modulus. However, physical characterization showed that the samples containing 0.5% graphene exhibited lower crystallinity compared to the reference and, for the blend with 1% graphene, the fluidity also decreased for the blend filled with the graphene compared to the reference blend without any filler. [ABSTRACT FROM AUTHOR]

This article emphasizes the significance of understanding the actual thermal properties of thermal insulation materials, which are crucial for avoiding errors in building design and estimating heat losses within the energy balance. The aim of this study was to analyse the thermal parameters of selected thermal insulation materials, particularly in the context of their stability after a period of storage under specific conditions. The materials chosen for this study include commonly used construction insulations such as polystyrene and mineral wool, as well as modern options like rigid foam composites. Experimental studies were conducted, including the determination of the thermal conductivity coefficient λ, as well as numerical analyses and analytical calculations of heat flow through a double-layer external wall with a window. The numerical analyses were performed using the TRISCO software version 12.0w, based on the finite element method (FEM). A macrostructural analysis of the investigated materials was also performed. The findings indicated that improper storage conditions adversely affect the thermal properties of insulation materials. Specifically, storing materials outdoors led to a deterioration in insulating properties, with an average reduction of about 4% for the standard materials and as much as 19% for the tested composite material. Insufficient understanding of the true thermal properties of insulation materials can result in incorrect insulation layer thickness, degrading the fundamental thermal parameters of external walls. This, in turn, increases heat loss through major building surfaces, raises heating costs, and indirectly contributes to greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

In this study five different complexes of Cu(II) were synthesized for the purpose of environmentally notorious mercury sensing and preliminary biological screening. Pyridine‐2,6‐dicarboxylic acid (also known as dipicolinic acid, and abbreviated as H2DPA), 3‐phenyl pyrazole (3‐ppz), 4‐iodo‐1H‐pyrazole (4‐ipz), 4‐nitropyrazole (4‐npz), 4‐bromopyrazole (4‐bpz), and 4‐chloropyrazole (4‐cpz) were chosen as potential ligands. The synthesized complexes labelled as 1–5, namely [Cu(DPA)(3‐ppz)], [Cu(DPA)(4‐ipz)], [Cu(DPA)(4‐npz)], [Cu(DPA)(4‐bpz)], [Cu(DPA)(4‐cpz)], were proposed based on spectroscopic data (FTIR, TGA, and UV‐visible spectroscopy). These complexes feature C=O functionalities that are not involved in coordination and may be used for further applications. The isolated complexes were utilized for detecting Hg(II) ions in water samples. Various concentrations of Hg(II) ions were prepared for detection purposes, and changes in absorption concerning complexes 1–5 were determined using UV‐Visible spectroscopy. It was found that complexes 3 and 4 exhibit efficient sensing abilities towards Hg(II) ions. The antibacterial activities of complexes 1–5 were assessed against S. typhi and E. coli. The complexes 1 and 3 displayed good antibacterial activities against S. typhi (13.67, and 13.56 mm, respectively) while complexes 1, 2 and 4 were found to be efficient against E. coli (11.6, 12.66, 11.31 mm, respectively). The absorption maxima of 2,2‐diphenyl‐1‐picryhydrazyl (DPPH) at 517 nm, considerably shifted upon addition of complexes 1–5. The results reveal that the complexes possess potential free radical scavenging abilities. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The aim of the study was to investigate the effect of potassium-based emulsifying salts (ES; 2% wt/wt concentration) with different phosphate chain lengths (dipotassium hydrogenphosphate [K 2 HPO 4 ; DKP], tetrapotassium diphosphate [K 4 P 2 O 7 ; KTPP], pentapotassium triphosphate [K 5 P 3 O 10 ; TKPP]) on the physicochemical, viscoelastic, textural, tribological, thermal, and sensory properties of processed cheese (PC; 40% wt/wt DM, 50% wt/wt fat in DM) during a 60d storage period (6°C ± 2°C). On the whole, the hardness of all PC samples increased with the increasing chain length of ES (DKP < TKPP < KTPP) and the prolonging storage period. Moreover, the hardness results were in accordance with those of the rheological analysis. All PC samples exhibited a more elastic character (G′ > G″; tan δ < 1). The type of potassium-based ES affected the binding of water into the structure of the PC. Furthermore, the study confirmed that the manufactured PC received optimal sensory scores, without any excessive bitterness. It could be concluded that the type of applied ES and storage length affected the functional properties of PC. Finally, the information provided in this study could serve as a tool for the dairy industry to help appropriately select potassium-based ES for PC manufacture with desired properties. [ABSTRACT FROM AUTHOR]