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By analyzing the relationship among the heat penetration depth, measurement frequency and detector characteristic parameters, a simple and practical $3\omega$ slope comparative method has been proposed. The corresponding measurement system for measuring the thermal properties of fluids and powder materials was established and verified using several specimens with known thermophysical parameters, such as alcohol, distilled water, and air. Compared to the two-dimensional model, the data processing of the method is relatively simple and quick. Due to the elimination of errors introduced by the detector parameter measurement, the measurement accuracy of the method is higher than the conventional one-dimensional model. By using an appropriate frequency range, the new method is time saving and convenient for measuring the thermal conductivity of fluids and powders with low thermal conductivity. Based on the analysis, the effective thermal conductivity of nano-SiO₂ powder is accurately determined.

The area of metallurgy has witnessed many advancements in the development of novel electrically conductive materials that shows exceptional mechanical as well as thermal properties. Nonetheless, traditional machining techniques encounter difficulties while machining hard materials. In order to address this limitation, electrical discharge machining (EDM) has emerged as a widely utilised method for machining of intricate geometries and the hard materials. EDM is a category of thermo-electric process that employs rapid recurring sparks between the electrode and work material, eroding the material without direct contact. As there is no contact between the electrode and work material, the issues related to machining defects such as mechanical stresses, clattering, and vibration eliminates. However, EDM have some limitations like poor surface finish and low volumetric material removal. To overcome these kind of limitations, the introduction of metallic powder into the dielectric fluid has been explored in powder-mixed electric discharge machining (PMEDM). This introduction of powder during the process leads to enhance the conductive strength of the fluid and increases the spark gap distance between the electrode and counter material. The inclusion of powder has a significant impact on the performance of the EDM process. Hence, this review aims to facilitate researchers in comprehending the concept of PMEDM and to examine the process parameters required to achieve improved levels of quality.

The water adsorption property of materials is a great factor to the mechanical property and durability of civil engineering structure. Therefore, the adsorption behavior of six materials including haydite, mineral powder, coal ash, multi-wall carbon nanotubes, diatomite and bottom ash powder was investigated by dynamic vapor sorption (DVS) apparatus. The sorption isotherm curves and sorption kinetic were analyzed and the conclusion is as follows. The adsorption isotherm curves for all these materials except carbon nanotubes is Type II isotherm curves, whereas the curve for carbon nanotubes is Type I isotherm curve. The change of geometry and existence of metastability may lead to adsorption hysteresis. The order of water adsorption ability of the six materials is: bottom ash powder > diatomite > carbon nanotubes > coal ash > mineral powder > haydite. Water vapor sorption process of carbon nanotubes, diatomite and bottom ash powder can be described by an exponential kinetic model. In addition, the method of dynamic vapor sorption test can provide a reference for other civil engineering materials.