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Pore structure and surface properties of diatomite with mechanical grinding and its influence on humidity control

Hu Zhibo, Zheng Shuilin, Li Jinyu, Zhang Shuaiqian, Liu Min, Wang Zhicheng, Li Jiaxin, Sun Hongjuan

Physicochemical Problems of Mineral Processing

2022

Vol. 58, iss. 6

art. no. 153509

Mechanical grinding (MG) is an effective method to regulate the pore structure and surface properties of mineral material. Grinding diatomite samples were prepared by horizontal sander under different grinding time. The pore structure and surface properties of grinding samples were characterized systematically by the particle size analysis, low temperature nitrogen adsorption, MIP, fractal theory, XRD, SEM, TEM, FTIR and surface hydroxyl density analysis. The humidity control performance (HCP) of grinding diatomite was tested under different temperature and relative humidity. The relationship among pore structure, surface properties and HCP was analyzed. The results show that macroporous is more easily damaged by mechanical force than mesoporous, and the internal blind holes structure can be opened. The HCP of diatomite is positively correlated with the specific surface area, mesoporous volume, the inhomogeneity of macroporous structure and the number of hydroxyl groups, while negatively correlated with the proportion of macroporous volume.

Comprehensive importance analysis for repairable system components based on the GO method

Jiang Xiuhong, Wang Yuying, Li Jiaxin, Ye Linlin

Eksploatacja i Niezawodność

2022

Vol. 24, no. 4

785--794

In order to effectively improve the reliability level of the permanent magnet synchronous motor (PMSM) drive system of electric aircraft, a component importance analysis based on the GO method for the repairable systems is proposed. Firstly, the system reliability model GO diagram is established according to the hardware schematic diagram of the PMSM drive system. Secondly, the steady-state availability and failure importance of the components are calculated. In addition, the criteria importance through intercriteria correlation (CRITIC) is adopted to determine the objective weights of steady-state availability and failure importance. The combined weighting is employed to obtain the importance of key components. Meanwhile, a system redundancy design based on the importance of components is proposed to provide data support for the design of the system. Finally, the feasibility and effectiveness of the proposed method are evaluated by an example of an electric aircraft PMSM drive system. This method provides a supporting basis for the optimization design of the entire system.

Energy management strategy of dual planetary hybrid electric vehicle based on optimal transmission efficiency

Wang Shangxu, Li Jiaxin, Shi Dehua, Sun Xiaoqiang, Yao Yong

Journal of Theoretical and Applied Mechanics

2019

Vol. 57 nr 2

383--396

A power split hybrid electric vehicle with dual planetary gear sets is studied in this paper. Firstly, the power split and circulation phenomenon are further described by analyzing a speed and torque relationship between the engine, motors and the output shaft based on the lever analogy. The transmission efficiency and the electric power ratio are then obtained. The working modes of the hybrid electric vehicle (HEV) are divided according to the system operation mechanism. On this basis, the engine optimal operating line (OOL) control strategy and the mechanical point (MP) control strategy are designed. Furthermore, a fuzzy controller is designed to realize the optimal torque distribution of the engine and the motors in the MP control strategy. Simulation results demonstrate that the MP control strategy can guarantee a higher efficiency of the transmission system, which also shows good performance in improving fuel economy of the HEV by adjusting the engine operating point.