monire taghvaei; nasim nayebpashaee
Abstract
RTV silicone rubber offers excellent high and low temperature resistance as well as UV and weathering resistance and has a bright future in the aerospace and electronics industries. On the other hand, the thermal decomposition behavior of polymeric materials significantly affects their aging process ...
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RTV silicone rubber offers excellent high and low temperature resistance as well as UV and weathering resistance and has a bright future in the aerospace and electronics industries. On the other hand, the thermal decomposition behavior of polymeric materials significantly affects their aging process and there are many studies on improving the specifications of nanocomposites by adding different types of nanoparticles. In this work, silicone rubber RTV nanocomposites with low content of modified nano-ZnO particles and pure RTV were compared in terms of their degradation behavior by heat and electrical stress. The coatings were prepared and the products were subjected to various experimental tests, including thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) analysis. The TGA results of the study suggest that the residual weight of the aged samples is higher than that of the unaged samples. The FTIR analysis results show that the aging performance of Nano-RTV is better than that of RTV, which is concluded from the smaller absorption area of the functional groups of Si-CH3 and Si-O-Si. The numeric value of Critical flashover voltage in Nano-RTV coating was higher compared to the RTV coating as a result of the enhanced electrical insulation characteristics. This can confirm the improvement of thermal aging of Nano RTV compared to pure RTV and may prove useful to estimate the expected lifetime of the coatings, which is valuable for estimating the reliability of porcelain insulators
monire taghvaei; mohammad javad nasiri
Abstract
With the growth of wind power energy’s importance throughout the world, losses caused by lightning strike to off-shore wind turbines are taken into consideration more than ever due to massive costs of installation and maintenance of the wind turbines. In this study, a new method for analyzing overcurrent ...
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With the growth of wind power energy’s importance throughout the world, losses caused by lightning strike to off-shore wind turbines are taken into consideration more than ever due to massive costs of installation and maintenance of the wind turbines. In this study, a new method for analyzing overcurrent created by a lightning strike to the turbines body and the distribution of magnetic and electrical fields around the wind turbine’s tower is presented for two different cases of the tower with one leg, and the other case tower with three legs, using FEKO and MATLAB software. In the major part of the simulation, which is done by the comprehensive electromagnetic simulator software for analyzing magnetic and electrical fields of 3D structures called FEKO, various environmental conditions are applied and the outputs are compared on different diagrams including current, electrical fields, and magnetic fields in various environmental conditions. The results of simulations indicate that with the decrease of ground’s resistivity, the peak of magnetic and electrical fields will decrease too which can be achieved by different methods and as a result of that, the losses caused by lightning strike to the turbine decreases
