A considerable amount of large scale heat pumps working mainly with Rl2 but also partially with Rll4 has been installed in Germany in the past. -As considerable investments have been made, a conversion from Rl2 to Rl34a seems to be an important task. Due to this reason a research project has been started at the University of Hannover to evaluate the possibility of such a conversion. To achieve ...

To study the effect of glycerin fatty acid ester (Poem TR-FB) concentrations on the dissolution rate of acetaminophen (APAP), the dissolution and disintegration behaviors of APAP tablets formulated using various lubricants were examined. The change over time in the available surface area of APAP (S(t)), which is in direct contact with solvent, was also analyzed using these dissolution data. In ...

A precision spin stand was used to study the effects of pitch static angle and roll static angle on lubricant transfer between a disk and a slider in a hard disk drive. The lubricant distribution on the slider was determined by timeof-flight secondary ion mass spectrometry, while the lubricant distribution on the disks was obtained using optical surface analysis. Lubricant transfer from the dis...

Perfluoropolyethers ~PFPE! are used extensively to lubricate hard disks for high density information storage. Some PFPE lubricants have been shown to be vulnerable to dissociative electron attachment as well as electron bombardment. Triboelectric charges generated during sliding contact may generate quasi-free electrons capable of degrading the lubricant. We describe measurements of triboelectr...

for button mushrooms packaging, the packaging films with high permeability to oxygen and carbon dioxide are required. permeability of plastic films such as pvc lead to loss of weight (and thus economic value) and textural changes are undesirable for button mushroom. so packaging film of polyolefins (pd 941 and pd 961) can be used. also the new film, hydrophilic materials such as films made from...

penicillin g acylase from e. coli ta1 was immobilized by cross-linked enzyme aggregates (clea), a new method for immobilization. this biocatalyst and commercial immobilized penicillin g acylase (pga-450) were used to study the effect of ph, temperature and substrate concentration on the synthesis of ampicillin from phenyl glycine methyl ester (pgme) and 6-aminopenicillanic acid (6-apa). compare...