A weight optimization method for chemical safety evaluation indicators based on the bipartite graph and random walk

Du Junwei,Jing Guanghui,Hu Qiang 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4

In the chemical safety evaluation system, the optimization of indicator weights needs to take both experts’ evaluations and the feedback on accident influences into account. Thus, this paper proposes a comprehensive weighting method based on the association bipartite graph (ABG). The accident influences and correlation intensity between the accident and the evaluation indicators are calculated on the ABG. A random walk algorithm, which integrates the objective influences of the accidents and the subjective evaluations of experts, is designed to realize the weight optimization. Experiments prove the effectiveness of the proposed method from the perspectives of weight ranking and fitting degree.

High-Temperature Activation of Zeolite-Loaded Fiber Sorbents

Sujan, Achintya R.,Koh, Dong-Yeun,Zhu, Guanghui,Babu, Vinod P.,Stephenson, Neil,Rosinski, Andrew,Du, Hai,Luo, Yang,Koros, William J.,Lively, Ryan P. American Chemical Society 2018 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.57 No.34

<P>Here, we describe the formation of zeolite LiX fiber sorbents and postfabrication activation at temperatures of 350-400 °C for use in air separations. Two polymers were considered as the support matrices for the LiX zeolites: Torlon (polyamide-imide) and Matrimid (polyimide). Torlon-based fiber sorbents exhibit approximately 4% mass loss during the high-temperature (370 °C) activation required for zeolites, which is close to the glass transition temperature of these polymers. This mass loss is accompanied by the formation of pyrolytic side products that ultimately resulted in contamination of the LiX crystals and a 73% reduction in N<SUB>2</SUB> sorption capacity at ambient temperatures. In contrast, Matrimid was found to be suitable for fiber sorbent synthesis with only 10-15% reduction in N<SUB>2</SUB> sorption capacity observed upon the thermal activation. A LiX loading of 73% in monolithic fibers (i.e., no bore) by weight was achievable. Experimental breakthrough tests at 25 °C were conducted on an activated fiber module consisting of densely packed LiX-Matrimid fiber sorbents and operated over a range of adsorption pressures (1-3.5 bar) that are often used in an actual pressure swing adsorption (PSA) process for air separation.</P> [FIG OMISSION]</BR>

Research on Grey Predictive Control of PMSM Based on Reduced-order Luenberger Observer

Huang Xianghui,Guan Penglin,Pan Hongguang,Liu Shulin,Du Guanghui,Huang Xinyi,Wang Xueyan 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.5

To further improve the dynamic and anti-interference performance of permanent magnet synchronous motor (PMSM) control system, a dual closed loop model predictive control (MPC) strategy combining with grey prediction and reduced-order Luenberger observer is proposed in this paper for speed and current control. To be specifi c, fi rstly, the dual closed loop MPC strategy is introduced based on the mathematical model of PMSM, that is, the model predictive controller is used for the outer loop of speed, and the deadbeat predictive controller for the inner loop of current. Secondly, considering the grey prediction method can establish grey model and whiten the system grey quantity to some extent, it is used in the PMSM control system to improve the dynamic performance. Finally, to solve the problem that the motor is easy to be aff ected by disturbances, a reduced-order Luenberger observer is designed to combine with the model predictive controller to improve the system anti-interference performance. The simulation results show that the dual MPC strategy based on grey prediction makes the system more stable and dynamic response faster, while the dual MPC strategy combining with the grey prediction and the reduced-order Luenberger observer makes the system more resistant to load disturbance.

High Frequency Torque Pulsation Suppression Strategy for Dual Winding Permanent Magnet Synchronous Motor Sensorless Control Based on Dual High Frequency Square Wave Injection Method

Zhou Qixun,Ma Ping’an,Gong Hao,Wang Pei,Du Guanghui 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5

To address the problem of high frequency torque pulsation in the zero-low-speed permanent magnet synchronous motor (PMSM) sensorless control by the high frequency square wave injection method, a torque pulsation suppression strategy based on the dual high frequency square wave injection method for the dual-winding permanent magnet synchronous motor (DW-PMSM) sensorless control is proposed. A high-frequency mathematical model of the PMSM is established, and the analytical relationship between the torque pulsation and the injection signal is analyzed. For a surface mounted DW-PMSM with two windings differing in γ electrical angle, the general form of the square wave signal that should be injected into the second winding is derived based on the position relationship between the two windings when the first winding is injected with a high-frequency square wave, with the objective of minimizing the equivalent high-frequency torque generated. The rotor position estimation error contained in the high-frequency signals of the two windings is extracted, and the rotor position estimation accuracy is improved by tracking the rotor position using a luenberger observer with the goal of minimizing the error. Simulation and experimental results show that the method is able to reduce torque pulsation by more than 50% and improve rotor position estimation accuracy by more than 4 times.

Fuzzy Approximation-Based Backstepping Control of Permanent Magnet Synchronous Motor

Zhang Yufeng,Yan Qi,Huang Nan,Wu Zihui,Gong Hao,Du Guanghui 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

A permanent magnet synchronous motor(PMSM) control system based on backstepping control can effectively improve the dynamic performance, and the design process is simple and easy to be implemented in engineering. However, factors such as changes in motor parameters due to environmental changes, wear and aging, and external load disturbances can adversely affect the control system, resulting in degraded control performance. To address this problem, this paper proposes a fuzzy approximation-based backstepping control method for PMSM. The method constructs a mathematical model containing the perturbation term of the PMSM body parameters and the load disturbance term. And the universal approximation property of the fuzzy logic system is used to approximate the disturbance terms in the model, based on which a backstepping controller satisfying the stability requirements is designed. Finally, the simulation and experiment are given, which compare with the traditional backstepping method. The results show that the proposed method can effectively suppress the adverse effects of motor parameter changes and load disturbances on the motor control system.

Active Speed Control of Belt Conveyor with Variable Speed Interval Based on Fuzzy Algorithm

Zhou Qixun,Gong Hao,Sun Wenhao,Yan Qi,Shi Keke,Du Guanghui 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Aiming at the problems of too fast adjustment frequency, unstable material flling rate and fuctuation of material fow at the boundary of speed interval caused by unreasonable setting of speed interval in traditional active speed control strategy based on hierarchical speed regulation. An active speed control strategy based on fuzzy algorithm is proposed for belt conveyor. The material flling rate of the belt is taken as input, and the double-layer fuzzy boundary is set according to the expected value of the material flling rate to adjust the speed of the belt conveyor. The adjustment time of diferent speed intervals is given according to the estimation-calculation-optimization method. The simulation results of the double belt conveyor system show that compared with the active speed control strategy based on hierarchical speed regulation, the active speed control strategy can not only stabilize the material flling rate of the downstream belt conveyor near the expected value and improve the stability of transportation, but also reduce the energy by about 20.69% per hour on average. The subsequent experimental results also verify the efectiveness of the proposed active speed control strategy, which can achieve more sustainable operation of the belt conveyor.

Dissecting the meteorological and genetic factors affecting rice grain quality in Northeast China

Chen Mojun,Li Zhao,Huang Jie,Yan Yongfeng,Wu Tao,Bian Mingdi,Zhou Jinsong,Wang Yongjun,Lyv Yanjie,Hu Guanghui,Jin Yong-Mei,Huang Kai,Guo Liping,Jiang Wenzhu,Du Xinglin 한국유전학회 2021 Genes & Genomics Vol.43 No.8

Background The Northeast Plain of China, which is an important region for the production of high grain quality rice in China. However, the grain quality of the rice produced varies across this region, even for the same cultivar. Objective In order to explore the meteorological factors that have the greatest infuence on quality and the transcriptional level diferences between diferent cultivars and diferent locations at grain flling stage. Methods We grew eight rice cultivars in three locations in Northeast China during two growing seasons (2017 and 2018). We recorded meteorological conditions, including air temperature, air temperature range, and photosynthetically active radiation (PAR) during the grain-flling stage of each cultivar, and analyzed the grain quality of those eight cultivars. Results Across all eight cultivars, meteorological factors had a stronger efect on eating quality than genotype, while genotype had a stronger efect on milling quality. Of the three environmental factors assessed, PAR was signifcantly correlated with the most grain quality traits. Using RNA-sequencing analysis, we identifed 573 environment-specifc DEGs (Diferentially Expressed Genes), and 119 genotype-specifc DEGs; 11 DEGs were responsive to genotype×environment interactions. These DEGs were involved in many key metabolic processes. Conclusion Our results indicated that interactions among environmental factors, especially PAR, afected rice quality in Northeast China. Further analyses of the DEGs identifed herein may provide useful information for future breeding programs aiming to develop high grain quality rice varieties suitable for cultivation across Northeast China.