This paper presented an overview on the dynamic analysis and control of the transmission tower-line system in the past forty years. The challenges and future developing trends in the dynamic analysis and mitigation of the transmission tower-line system under dynamic excitations are also put forward. It also reviews the analytical models and approaches of the transmission tower, transmission lines, and transmission tower-line systems, respectively, which contain the theoretical model, finite element (FE) model and the equivalent model; shows the advances in wind responses of the transmission tower-line system, which contains the dynamic effects under common wind loading, tornado, downburst, and typhoon; and discusses the dynamic responses under earthquake and ice loads, respectively. The vibration control of the transmission tower-line system is also reviewed, which includes the magnetorheological dampers, friction dampers, tuned mass dampers, and pounding tuned mass dampers.
SAPO-5 zeolite with a bimodal pore system was hydrothermally synthesized using di-n-butylamine as single template. The structural and catalytic properties of the hierarchical SAPO-5 were extensively characterized and compared to those of conventional SAPO-5 using triethylamine as template.
The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE) model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.
Sacrificial carbon coating over NiMo/Al2O3 catalyst effectively tailor the interaction between the active phase and support, which result in more easily reducible active components and enhanced HDS performance.
A simple and solvent-free solid-state method was used to prepare NiMo–Al2O3 hydrodesulfurization (HDS) catalysts using Ni(NO3)2·6H2O, (NH4)6Mo7O24·4H2O, and AlCl3·6H2O as the solid raw materials and polyethylene glycol (PEG) as an additive.
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