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In order to apply digital radiography to the spacecraft, an improvement of the resolution for the flat panel detector has been studied. A higher resolution has been obtained by the following methods: First, the resolution of the scintillator has been gained by improving the granular nature of crystal and cross talk. Secondly, the silicon wafer has been improved by suppressing the collection of the electric charge generated in portions other than the photodiode. The resolution of the improved flat panel detector using the X-ray test chart was found to be 8.7 Lp/mm as contrasted to 6.3 Lp/mm of the detector before improvement. The image quality level has been studied under different radiographic parameters (tube-voltage, distance between the focal spot and flat panel detector, accumulation time, etc.), and appropriate conditions have been examined for developing this detector. Examples of radiographic images are shown in comparison with the results of X-ray film.

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An attempt was made to scale up the microporous hydrophobic membrane bioreactor with special regard to the lipase-catalyzed glycerolysis of fat. The continuous glycerolysis of olive oil was carried out using Pseudomonas fluorescens lipase with single and multiple piled-up units of the flat micron porous polypropylene membrane Bioreactor developed by the authors. Membrane area ranged from 0.0726 m2 to 1.16 m2 (16-fold scale-up). Two operational modes of the multiple piled-up units, i.e., parallel flow and series flow, were compared. Despite different membrane areas and regardless of these different operational modes, the relationship between conversion and oil flow rate per sheet of membrane was the same and that between the relative content of monoglyceride, diglyceride and triglyceride in the product and the oil flow rate per sheet was also the same. The development of the bioreactor might be attained using the criterion based on (oil flow rate)/(total membrane area) as long as the same membrane and configuration are used.

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