M. R. Soltani, M. Seddighi, and A. Bakhshalipour,
Volume 26, Issue 1 (7-2007)
Abstract
The blades of wind turbines are the most important parts in producing power output. In this study, a section of a 660 KW wind turbine blade will be installed in Iran in near future was tested in a wind tunnel. In addition to steady tests, various unsteady tests including the effects of reduced frequency, mean angle of attack, and amplitudes were carried out. The preliminary results show strong effects of reduced frequency on the aerodynamic coefficients of the airfoil. Moreover, increasing the reduced frequency delays dynamic stall angle of attack but increases lift and drag coefficients compared to the static results. Further, the values of the aerodynamic coefficients in the upstroke motion (increasing angle of attack) are different from their corresponding values in the downstroke (decreasing angle of attack). These differences create a hysteresis loop where its width and shape are strong functions of reduced frequency, mean angle of attack, and amplitudes.
H. Fallah-Arani, S. Baghshahi, A. Sedghi, F. Shahbaz Tehrani,
Volume 40, Issue 2 (9-2021)
Abstract
In this research, the influence of titanium dioxide nanoparticles on the structural and magnetic properties of high-temperature superconductor Bi1.6Pb0.4Sr2Ca2Cu3O10+θ (Bi-2223) from the Bi-based ceramic system (BSCCO) was studied. In order to investigate the synthesized samples, X-ray diffractometry and magnetic measurements were performed. Based on the magnetic measurements, the superconductivity transition temperature declined with the increase in the nanoparticles' content. The addition of nanoparticles affected on the hysteresis loop width. Accordingly, the compound containing 0.2 wt.% nanoparticles had the maximum magnetization, hysteresis loop width, and critical current density.
