For the traditional single-side planetary abrasive lapping process particle trajectories passing over the target surface are found to be periodically superposed due to the rational rotation speed ratio of the lapping plate to workpiece that could affect the material removal uniformity and hence its surface quality. This paper reports on a novel driving system design with combination of the tapered roller and contact roller to realize the irrational rotation speed ratio of the lapping plate to workpiece in the single-side planetary abrasive lapping process for the improvement of surface quality. Both of the numerical and experimental investigations have been conducted to evaluate the abrasive lapping performance of the novel driving system. It has been found from the numerical simulation that particle trajectories would theoretically cover the whole target surface if the lapping time is long enough due to their non-periodic characteristics, which can guarantee the uniformity of material removal from the surface of workpiece with relatively high surface quality. The encouraging experimental results underline the potential of the novel driving system design in the application of the single-side planetary abrasive lapping for the improvement of the surface quality in terms of surface roughness and material removal uniformity.

Studying the cutting temperature is critical for unlocking the secrets of sawblade wear, lifespan, and the metallurgical alterations beneath the surface. This paper describes an investigation into the temperature of 45 steel during dry sawing, using a cemented carbide circular saw blade under various cutting conditions. A temperature acquisition system was developed, enabling the determination of the average temperature of the arc zone in the workpiece and the temperature of the sawtooth tip via a semi-automated thermocouple measurement and an embedded dynamic artificial thermocouple method, respectively. Results obtained from these two methods indicate a positive correlation between the sawing temperature and the saw blade speed and feed rate, with an optimal combination of cutting process parameters identified for maintaining stability within reasonable ranges. Finite element simulations reveal a cyclical fluctuation in temperature along the workpiece surface and sawtooth, with a gradual decrease after an increase in the intermittent step, and confirm the relationship between the sawing temperature and the saw blade and feed rates observed experimentally. Overall, this study presents valuable insights into the temperature changes occurring during the sawing process, with important implications for improving productivity and maintaining stability in industrial applications.

Gun barrels are subjected to time-varying high-intensity heat flux under multiple firing, which may damage the material and limit the overall performance of the gun. In order to monitor the thermal state of a gun barrel, an inverse method coupling the finite difference method with the sequential function specification method was developed to estimate the unknown time-varying heat flux imposed on the inner wall of a gun barrel. A two-layer hollow cylindrical tube was assumed with the convection heat transfer boundary condition on the outer wall of the tube. A direct heat transfer model was developed, and was used to estimate the temporal distribution of boundary heat flux in approximately real time based on the measured transient temperature at some positions on the outer wall of the gun barrel. Numerical tests were performed to verify the effectiveness and reliability of this method by investigating the influence of temperature measurement noises and future time step selection. The results show that the proposed method has high precision and efficiency in extracting the time-varying heat flux under one-shot and three-shot firing conditions. When there is a measurement noise, this method has good anti-illness characteristics and can achieve better results by appropriately selecting the value of a future time step.

—In order to provide fast, accurate, and low cost shock sensitivity calibration of acceleration sensors, a pneumatically operated piston shock calibrator based on ISO 16063-22 is designed. comparative calibration method is used to calibrate the shock sensitivity of tested sensor within a shock peak amplitude of 25 to 2000 g and a pulse duration of 0.1 to 3 ms. The pneumatically operated piston shock calibrator includes modules of mechanical shock, shock signal generation, and measurement control based on the NI data acquisition card and LabVIEW control program. Numerical analysis and calculation of the pneumatic ejection process by MATLAB is performed to analyze the influence factors and levels of the impact velocity. Moreover, experiments on key performance indexes and test data processing are carried out. The repeatability of shock peak amplitude and pulse duration are better than 1.24 and 2.19%, respectively, which reaches the level of the commercially available calibrator of the same type. Meanwhile, the calibrated uncertainty is 2.56% (k = 2), which meets the ISO 16063-22 requirement with the accuracy of less than 5%.

Low-temperature radiant heating systems utilizing heating cables face challenges including low heat dissipation efficiency and high energy consumption, hindering widespread application. Graphene coatings, characterized by high thermal conductivity and far-infrared radiation properties, offer a novel approach to enhance cable heat dissipation efficiency. This study systematically investigates the effects of coating position, thickness, and ambient temperature on cable heat dissipation using numerical simulations and experiments. A three-dimensional heat transfer model of the heating cable was established using Fluent software (2022R1). The radiation heat transfer equation was solved using the Discrete Ordinates (DO) model, and the coating position and thickness parameters were optimized. The reliability of the simulation results was validated using a temperature-rise experimental platform. The results indicate that graphene coatings significantly improve the heat dissipation performance of cables. Under optimal parameters (coating thickness: 100 μm, coating position: aluminum fin surface, initial temperature: 5 °C), the heat flux increased by approximately 26%, aluminum fin surface temperature decreased to 41.5 °C, and experimental temperature-rise efficiency improved by nearly 50%. The discrepancy between simulated and experimental results was within 8.5%. However, when coating thickness exceeded 100 μm, interfacial thermal resistance increased, reducing heat dissipation efficiency. Additionally, higher ambient temperatures suppressed heat dissipation. These findings provide a theoretical basis for optimizing the energy efficiency of low-temperature radiant heating systems.