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Performance of wind-excited 1000 kV substation gantry by aeroelastic model wind tunnel test
Feng Li,Yin Chen,Lianghao Zou,Jie Song,Shu-Guo Liang 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.33 No.4
This study aims to investigate the performance of wind-excited 1000 kV substation gantry via the aero-elastic model wind tunnel test. An aero-elastic model that can simulate the first four frequencies was designed and manufactured by the method of combining semi-rigid segments by V-shape springs. Making use of the aero-elastic model wind tunnel test, the structural displacement and acceleration responses of the model were investigated for different wind speed and wind direction cases. Results show that the method of combining semi-rigid segments by V-shape springs can simulate the key parameters such as geometric shape, mass, frequency and damping ratio well. Wind direction plays an important role in the mean displacement responses, and the worst wind direction is 15° deviating from the corresponding axis. The root mean square of acceleration responses is remarkable in both the along-wind and cross-wind directions. In the direction perpendicular to the span, the windinduced vibration of the middle tower mainly depends on the resonance component of the first mode. By contrast, the contributions of the first and higher modes are all important for the side towers’ wind-induced responses. Gust response factors (GRFs) were estimated by the inertial wind loading method and the gust loading factor method, respectively. The range of the GRFs determined by the two methods is close to each other, which can provide guidance for assessing the performance of similar substation gantries subjected to wind.
Zhang De,Luo Run,Yin Ye-bo,Zou Shu-liang 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.5
This paper presents a hybrid algorithm to solve the multi-objective path planning (MOPP) problem for mobile robots in a static nuclear accident environment. The proposed algorithm mimics a real nuclear accident site by modeling the environment with a two-layer cost grid map based on geometric modeling and Monte Carlo calculations. The proposed algorithm consists of two steps. The first step optimizes a path by the hybridization of improved ant colony optimization algorithm-modified A* (IACO-A*) that minimizes path length, cumulative radiation dose and energy consumption. The second module is the high radiation dose rate avoidance strategy integrated with the IACO-A* algorithm, which will work when the mobile robots sense the lethal radiation dose rate, avoiding radioactive sources with high dose levels. Simulations have been performed under environments of different complexity to evaluate the efficiency of the proposed algorithm, and the results show that IACO-A* has better path quality than ACO and IACO. In addition, a study comparing the proposed IACO-A* algorithm and recent path planning (PP) methods in three scenarios has been performed. The simulation results show that the proposed IACO-A* algorithm is obviously superior in terms of stability and minimization the total cost of MOPP
( Ouyang Ping ),( Sun Mao ),( He Xuewen ),( Wang Kaiyu ),( Yin Zhongqiong ),( Fu Hualin ),( Li Yinglun ),( Geng Yi ),( Shu Gang ),( He Changliang ),( Liang Xiaoxia ),( Lai Weiming ),( Li Lixia ),( Zou 한국미생물 · 생명공학회 2017 Journal of microbiology and biotechnology Vol.27 No.1
Staphylococcus aureus (S. aureus) is a common gram-positive bacterium that causes serious infections in humans and animals. With the continuous emergence of methicillin-resistant S. aureus (MRSA) strains, antibiotics have limited efficacy in treating MRSA infections. Accordingly, novel agents that act on new targets are desperately needed to combat these infections. S. aureus alpha-hemolysin plays an indispensable role in its pathogenicity. In this study, we demonstrate that sclareol, a fragrant chemical compound found in clary sage, can prominently decrease alpha-hemolysin secretion in S. aureus strain USA300 at sub-inhibitory concentrations. Hemolysis assays, western-blotting, and RT-PCR were used to detect the production of alpha-hemolysin in the culture supernatant. When USA300 was co-cultured with A549 epithelial cells, sclareol could protect the A549 cells at a final concentration of 8 μg/ml. The protective capability of sclareol against the USA300-mediated injury of A549 cells was further shown by cytotoxicity assays and live/dead analysis. In conclusion, sclareol was shown to inhibit the production of S. aureus alpha-hemolysin. Sclareol has potential for development as a new agent to treat S. aureus infections.