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The low thermal conductivity, poor toughness, and non‐reprocessability of thermosetting epoxy resins severely restrict their applications and sustainable development in flexible electronics. Herein, liquid crystalline epoxy (LCE) and dynamic ester and disulfide bonds are introduced into the cured network of bisphenol A epoxy resin (E‐51) to construct highly thermally conductive flexible liquid crystalline epoxy resin (LCER) vitrimers. LCER vitrimers demonstrate adjustable mechanical properties by varying the ratio of LCE to E‐51, allowing it to transition from soft to strong. Typically, a 75 mol% LCE to 25 mol% E‐51 ratio results in an in‐plane thermal conductivity (λ) of 1.27 W m−1 K−1, over double that of pure E‐51 vitrimer (0.61 W m−1 K−1). The tensile strength and toughness increase 2.88 folds to 14.1 MPa and 2.45 folds to 20.1 MJ m−3, respectively. Besides, liquid crystalline phase transition and dynamic covalent bonds enable triple shape memory and three‐dimensional shape reconstruction. After four reprocessing cycles, λ and tensile strength remain at 94% and 72%, respectively. Integrating carbon nanotubes (CNTs) imparts photo‐thermal effect and enables “on” and “off” switch under near‐infrared light to LCER vitrimer. Furthermore, the CNTs/LCER vitrimer displays light‐induced actuation, self‐repairing, and self‐welding besides the closed‐loop recycling and rapid degradation performance. The combination of liquid crystalline epoxy and dynamic covalent bonds creates highly thermally conductive liquid crystalline epoxy resin (LCER) vitrimers with multi‐shape memory and closed‐loop recycling capabilities. The 0.5 wt% introduced carbon nanotubes enable LCER vitrimers with photothermal conversion and near‐infrared light‐induced actuation, providing insights for designing recyclable materials with special functions, such as soft actuators and intelligent wearable electronics.

We have developed a system for simultaneous measurement of the electrical conductivity and Seebeck coefficient for thermoelectric samples in the temperature region of 300 K to 1000 K. The system features flexibility in sample dimensions and easy sample exchange. To verify the accuracy of the setup we have referenced our system against the NIST standard reference material 3451 and other setups and can show good agreement. The developed system has been used in the search for a possible high-temperature Seebeck standard material. FeSi 2 emerges as a possible candidate, as this material combines properties typical of thermoelectric materials with large-scale fabrication, good spatial homogeneity, and thermal stability up to 1000 K.

In this paper, an advanced electrothermal simulation strategy is applied to a 3.3 kV silicon carbide MOSFET power module. The approach is based on a full circuital representation of the module, where use is made of the thermal equivalent of the Ohm’s law. The individual transistors are described with subcircuits, while the dynamic power-temperature feedback is accounted for through an equivalent thermal network enriched with controlled sources enabling nonlinear thermal effects. A synchronous step-up DC-DC converter and a single-phase inverter, both incorporating the aforementioned power module, are simulated. Good accuracy was ensured by considering electromagnetic effects due to parasitics, which were experimentally extracted in a preliminary stage. Low CPU times are needed, and no convergence issues are encountered in spite of the high switching frequencies. The impact of some key parameters is effortlessly quantified. The analysis witnesses the efficiency and versatility of the approach, and suggests its adoption for design, analysis, and synthesis of high-frequency power converters in wide-band-gap semiconductor technology.

The reported thermal conductivity (κ) of suspended graphene, 3000 to 5000 watts per meter per kelvin, exceeds that of diamond and graphite. Thus, graphene can be useful in solving heat dissipation problems such as those in nanoelectronics. However, contact with a substrate could affect the thermal transport properties of graphene. Here, we show experimentally that κ of monolayer graphene exfoliated on a silicon dioxide support is still as high as about 600 watts per meter per kelvin near room temperature, exceeding those of metals such as copper. It is lower than that of suspended graphene because of phonons leaking across the graphene-support interface and strong interface-scattering of flexural modes, which make a large contribution to κ in suspended graphene according to a theoretical calculation.

Silicon is investigated as a low-cost, Earth-abundant thermoelectric material for high-temperature applications up to 900 K. For the calculation of module design the Seebeck coefficient and the electrical as well as thermal properties of silicon in the high-temperature range are of great importance. In this study, we evaluate the thermoelectric properties of low-, medium-, and high-doped silicon from room temperature to 900 K. In so doing, the Seebeck coefficient, the electrical and thermal conductivities, as well as the resulting figure of merit ZT of silicon are determined.

The temperature increase induced by radioactive waste decay generates the thermal pressurisation around the excavation damage zone (EDZ), and the excess pore pressure could induce fracture re-opening and propagation. Shear strain localisation in band mode leading to the onset of micro-/macro-cracks can be always evidenced before the fracturing process from the lab experiments using advanced experimental devices. Hence, the thermal effects on the rock behaviour around the EDZ could be modelled with the consideration of development of shear bands. A coupled local 2nd gradient model with regularisation technique is implemented, considering the thermo-hydro-mechanical (THM) couplings in order to well reproduce the shear bands. Furthermore, the thermo-poro-elasticity framework is summarized to validate the implemented model. The discrepancy of thermal dilation coefficient between solid and fluid phases is proved to be the significant parameter leading to the excess pore pressure. Finally, an application of a heating test based on Eurad Hitec benchmark exercise with a drift supported by a liner is studied. The strain localisation induced by thermal effects is properly reproduced. The plasticity and shear bands evolutions are highlighted during the heating, and the shear bands are preferential to develop in the minor horizontal principal stress direction. Different shear band patterns are obtained with changing gap values between the drift wall and the liner. A smaller gap between the wall and the liner can limit the development of shear bands.HighlightsThe formulation of a coupled local 2nd gradient model considering the thermo-hydro-mechanical (THM) couplings.Validation of the model with comparison with analytical solution of thermo-elastic problem.The prediction of strain localisation pattern induced by thermal effects around a large scale drift.The analysis of the gap distance (between the drift wall and the liner) on the strain localisation process under the thermal loading.

Recent advances in thermoelectric technologies have made exhaust-based thermoelectric generators (TEGs) promising to recover waste heat. The thermal performance of the heat exchanger in exhaust-based TEGs is studied in this work. In terms of interface temperature and thermal uniformity, the thermal characteristics of heat exchangers with different internal structures, lengths, and materials are discussed. Following computational fluid dynamics simulations, infrared experiments are carried out on a high-performance production engine with a dynamometer. Simulation and experimental results show that a plate-shaped heat exchanger made of brass with fishbone-shaped internal structure and length of 600 mm achieves a relatively ideal thermal performance, which is practically helpful to enhance the thermal performance of the TEG.

As consumers increasingly prefer “all-natural” and healthy foods, there has been increasing demand for non-toxic, residual-free, and environmentally friendly food processing techniques. Researchers and developers have shown increasing interest in innovative electrical processing techniques for the treatment of foods. Among electrotechnologies, induced electric fields (IEF) demonstrates the potential advantages to food processing. It combined with thermal effect and non-thermal effect has been explored for sterilization, modification, and extraction of agro-food materials. It is a sister electrotechnology of ohmic heating, which does not require the use of electrodes. Despite valuable contributions to the literature, there still lack of knowledge regarding the application of IEF treatment to food products. It has proven effective in inactivating microorganisms and enzymes in foods, changing biomacromolecule contents, extracting active constituents, and enhancing chemical reactions. This paper provides an overview of current application of IEFs in the treatment of foods. Issues relevant to electric field processing (e.g., basic principles, formulas) are also examined as they affect IEF techniques. Future perspectives and challenges related to technological application of IEFs are outlined in an effort to fill research gaps. IEF processing is projected to become a key technology in the food industry.

Bulk multifilled n - and p -type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT  = 0.76 for p -type La 0.8 Ba 0.01 Ga 0.1 Ti 0.1 Fe 3 CoSb 12 and ZT  = 1.0 for n -type La 0.3 Ca 0.1 Al 0.1 Ga 0.1 In 0.2 Co 3.75 Fe 0.25 Sb 12 skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La 0.8 Ba 0.01 Ga 0.1 Ti 0.1 Fe 3 CoSb 12 sample. The thermal stability of the La 0.8 Ba 0.01 Ga 0.1 Ti 0.1 Fe 3 CoSb 12 skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C.

The absence of safe and efficient hydrogen storage technologies is the major bottleneck for widespread applications of hydrogen energy. Reactive hydride composites with high gravimetric and volumetric hydrogen densities are ideal hydrogen storage materials. However, their traditional dehydrogenation processes normally involving electric‐thermal‐chemical energy conversion require high operating temperatures and substantial energy inputs to heat the reactor and oven. In this study, using LiBH4−2LiNH2 as a model system, that rapid dehydrogenation via a photo‐thermal‐chemical and/or photo‐chemical energy conversion initiated by direct light irradiation is demonstrated and can be fulfilled in the presence of a catalyst and a photothermal agent. The experimental results revealed that the non‐thermal effect of UV light plays a critical role in reducing the desorption temperature and enhancing the dehydrogenation kinetics. The collective photothermal and non‐thermal effects drove over 8.0 wt.% hydrogen desorption from LiBH4−2LiNH2 within 5 min, which is ≈60 times faster than the thermal dehydrogenation process at the same temperature. The N−H bond in the [NH2]− ion group is significantly weakened by the non‐thermal effect of UV light, leading to a 60‐fold increase in dehydrogenation rate at the same temperature. As a result, over 8.0 wt.% H2 is released within 5 min.