The improvement in reverse recovery of power NPN bipolar transistor (BJT) through incorporation of ‘‘universal contact’’ in the base is studied in detail. It is shown that use of universal contact allows redistribution of base current in saturation from collector region where recombination lifetime is high to extrinsic base region where effective recombination lifetime is low. The reverse recov...

A solar absorption icemaker was designed. It is an intermittent system and uses Calcium Chloride and Ammonia as absorbent and refrigerant respectively. The single glazed collector/absorber/generator unit uses a plane glass sheet as the outer cover. Overall collector plate exposed area is 1.0m. A thermodynamic simulation of the icemaker has been performed in order to investigate the effect that ...

A system is being tested for recovery of rf power by conversion to DC pulsed power. The system consists of a cyclotron autoresonance accelerator (CARA) [1,2], and a single stage depressed collector (Fig. 1). A 50 kV, 5 A electron beam is injected into CARA, and up to 1 MW of S-band rf power is absorbed by the beam with efficiency exceeding 95%. The beam then passes to a single stage depressed c...

in this study, the possibility of producing coal with less than 11% ash from tailings of flotation process was investigated. the effect of six flotation parameters: collector type, collector consumption, frother type, frother consumption, pulp density and mixing rate were studied on a sample from a tailing dam. a software based experimental design approach (dx7) was applied to determine and mod...

The possibility of using flat plate collector in northern parts of Iran specially city of Rasht has been investigated in this paper. According to the high humidity in the northern parts of this country, diffuse radiation plays a more important role than direct radiation. This fact can change the results of delivered solar energy and the best tilt angle of the collector compared to the sunny cen...

The garbage collector presented in this paper makes use of two well known compaction garbage collection algorithms with very diierent performance characteristics: Cheney's two-space copying collector and Jonker's sliding compaction collector. We propose a scheme which allows either collector to be used. The run-time memory requirements of the program being executed are used to determine the mos...

Transport of colloidal particles in porous media is governed by the rate at which the colloids strike and stick to collector surfaces. Classic filtration theory has considered the influence of system hydrodynamics on determining the rate at which colloids strike collector surfaces, but has neglected the influence of hydrodynamic forces in the calculation of the collision efficiency. Computation...

For a solar thermal system, increasing the heat transfer area can increase the output temperature of the system. However, this approach leads to a bigger and bulkier collector. It will then increase the cost and energy needed to manufacture the solar collector. This study is carried out to estimate the potential to design a smaller solar collector that can produce the same desired output temper...

Overview Pretenuring is a technique for reducing copying costs in garbage collectors. When pretenuring, the allocator places long-lived objects into regions that the garbage collector will rarely, if ever, collect. We extend previous work on profiling-driven pretenuring as follows. (1) We develop a collector-neutral approach to obtaining object lifetime profile information. We show that our col...

this paper proposes an efficient network architecture to improve energy consumption in wireless sensor networks (wsn). the proposed architecture uses a mobile data collector to a partitioned network. the mobile data collector moves to center of each logical partition after each decision period. the mobile data collector must declare its new location by packet broadcasting to all sensor nodes. h...