outdoor experiments on a once-through single glazed solar air heater with perforated metal absorber plate were conducted to determine the practical effect of absorber plate porosity as well as suction air flow rate on the collector thermal efficiency and its total pressure drop. three aluminum absorber plates were made perforated by drilling circular holes with different diameter/pitch ratios i...

This brief announcement provides a high level overview of a parallel mark-split garbage collector. Our parallel design introduces and makes use of an efficient concurrency control mechanism based on a lock-free skip-list design for handling the list of free memory intervals. We have implemented the parallel mark-split garbage collector in OpenJDK HotSpot as a parallel and concurrent garbage col...

This paper reports the thermal performance of a new cylindrical solar collector based on an experimental investigation with this difference that instead of the collector tube with absorbent coating, coil into a spiral copper tube is placed in the center of the collector. The spiral shape of the tube, heat transfer without disruption or increase the heat transfer area, is increasing. In this cas...

This paper demonstrates the advantages of extending the scope of prototyping to the requirements capture phase of a project. Prototyping has long been used to elicit users’ responses to ready-formed designs (Boehm, 1988), but only recently has the use of concept demonstrators (Sanderson, 1997) and early throw-away prototypes (Smith et al., 1990) been suggested as a means to capture response to ...

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...

The solid beta-cyclodextrin (beta-CyD) complex of O-cinnamyl S-methyl dithiocarbonates (xanthate, 1a), upon heating at 45 degrees C, underwent asymmetric [3,31-sigmatropic rearrangement to give the optically S-(1-phenylallyl) S-methyl dithiocarbonate (2a) with 60% ee. Heating the beta-CyD complex of 2a at 120 degrees C caused extrusion of COS to give cinnamyl methyl sulfide (3a) in high yield. ...

1,4-Diols resulting from the double addition of ArCCLi (Ar = Ph, substituted phenyl, 2-thienyl) to ortho-C6H4(CHO)2 undergo cascades to tetracenes on simple admixture of LiHDMS, CS2 and MeI. Acene formation proceeds by [3,3]-sigmatropic rearrangement of xanthate anions followed by 6π electrocyclisations. The reactions are terminated by E2 or anionic Chugaev-type eliminations. Structural packing...

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...