A THz generating, low temperature grown semi-Insulating Gallium Arsenide photo conductive semiconductor switch was analyzed for optimum pulse amplitude for high power applications. The switching ...voltage which controls the substrate conditions for the given geometry was determined by monitoring the conditions in the trap-filled substrate region of the switch during the charging state. Trap occupancy, current flow lines, and the electric field were the major parameters monitored. The switch was illuminated for 350 fs with a 0.78 μm beam, and a power density of 50 Mw/cm 2 . Results show that the switch produces a central frequency of 1.75 Terahertz, with a pulse amplitude of approximately 0.22 A at an optimum bias voltage of 1100 Volts. The FWHM of the generated pulse 0.4 ps, and the rise time is 0.275 ps.
The use of composite materials has increased significantly, especially in the manufacture of wind turbine blades. Therefore the mechanical behaviors of these materials have to be evaluated. In this ...work four composite materials were investigated (Carbon fiber, Kevlar49 fiber, E-glass fibers and S-glass fibers). A developed model under Ansys Composite Prepost (ACP) has been used to assess the mechanical strength and stiffness of the composite blade to determine the optimal configuration. In this context, parametric studies were carried out, in order to evaluate the fiber orientation and material properties effect on the mechanical behavior of multilayered blade. The results show that the configurations (Carbon fiber, ±35), (Kevlar49 fiber, ±35) and (Kevlar49 fiber, ±45) are the most efficient configurations in terms of resistance to mechanical stress. Besides, the orientation configuration 90/0 support more than the other suggested configurations to flexural displacement with approximately 34.14 mm for the Carbon ±55 configuration.
