Power Electronics have proved itself as an encompassing field for power generation and 1IlaI1ag4:me Traditionally conversion of ac to de vo~es has been dominated by phase controlled or diode rectifiers. The ideal character of the input current draWnby these rectifiers creates number of problems like increase in .. power, high input current harmonics and low input power factor, lower rectifier e...

Two basic designs have been developed for waveguide hybrids, or 3-dB couplers, capable of handling hundreds of megawatts at X-band. Coupling is provided by one or two connecting waveguides with h-plane junctions and matching elements. In the former case, the connecting waveguide supports two modes. Small apertures and field-enhancing ebends are avoided to reduce the risk of rf breakdown. The h-...

This paper uses detailed weekly data on sales of hardcover fiction books to evaluate the impact of the New York Times bestseller list on sales. In order to circumvent the obvious problem of simultaneity of sales and bestseller status, the analysis exploits time lags and accidental omissions in the construction of the list. The estimates suggest that appearing on the bestseller list results in a...

this paper presents a novel control approach used in shunt active power filter based on variable structure control combined with random pwm technique (rvsc) that provides robust, fast, and more favorable performance for active power filter. this control strategy is compared with two other strategies to show the effectiveness of the introduced methods; pulse width modulated proportional-integral...