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Hybrid solar and electric lighting (HYSEL) systems constitute the latest generation of lighting systems for advanced life support, exhibiting continued potential for reducing the significant electrical power demand of current bioregenerative life support systems (BLSS). Two experimental HYSEL systems were developed: one employing xenon-metal halide (XMH) lamps and the other adopting light-emitting diodes (LEDs) as the electric-lighting components, and both using a mirror-based, fiberoptic-based solar collection system. The results showed that both the XMH and LED HYSEL systems effected reduced effective plant growing volume, indicating potential for a compact plant hardware design. The apparent electrical conversion efficiency of the LED HYSEL system exceeded that of the XMH HYSEL system by five-fold. Both the XMH and LED HYSEL systems provided reasonably acceptable spectral quality and lighting uniformity.

For the prediction of pumping loss in the engine crankcase at the early stage of engine design, a similarity law of the pumping loss on parallel cylinders with the phase difference of 180 degrees has been derived from the sum of the power loss due to the drag force of airflow through the cylinder bulkhead holes and the inertia force of fluid. It has been found that the mean effective pressure in the crankcase is in proportion to the square of the mean flow velocity at the bulkhead holes. Then, in order to validate the similarity law, by using a prototype engine with inline four cylinders, the pumping loss was estimated by subtracting the frictional loss with special pistons that had air holes, from the power loss in which the area of the bulkhead holes and engine speed were changed. The experimental results of the pumping loss were normalized by the similarity law. As a consequence, it has been shown that the pumping loss obeys the law.