Design and demonstration of a switching engine for a binary true-time-delay device that uses a white cell

Optical true-time-delay devices based on the White cell can be divided into two general types: polynomial cells, in which the number of delays that can be obtained is related to the number of times m that a beam bounces in the cell raised to some power, and exponential cells, in which the number of delays is proportional to some number raised to the power of m. In exponential cells, the topic to be addressed, the spatial light modulator switches between a delay element and a null path on each bounce. We describe an improved design of this switching engine, which contains a liquid-crystal switch and a White cell. We examine astigmatism and corrections for it and present a specific design.     

Studies on collector-cum-storage type solar water heaters under arid zone conditions of india

Conventional natural circulation type solar water heaters are very costly. Though manufactured in India, they are beyond the reach of the common man. To reduce the cost, a collector-cum-storage type solar water heater has been developed and its detailed study has been carried out and reported. The heater can provide 100 1 of hot water at a temperature of 55–60°C in the evening which can be retained at 40–45°C until the next morning. The efficiency of the heater varies from 57.4 to 66.0 per cent depending on design parameters.