Comparison of the Compaction Characterisitics of Selected Food Powders by Vibration, Tapping and Mechanical Compression

The compaction characteristics of selected powders in tapping could be described by either Sone's model or by a single term exponential equation. The Hausner ratio, i.e., the ratio between tapped and loose density, calculated by using these models was found to be a sensitive and useful indictor of the compaction mechanism in different types of tapping tests. The latter, especially where particle attrition was evident, could produce distinctly different compaction patterns. No correlation was found between these powders, Hausner's ratio, and their compressibility in mechanical compaction.     

Runoff and infiltration characteristics of pavement structures--review of an extensive monitoring program.

The stormwater runoff and infiltration performance of permeable pavements has been systematically evaluated within an intensive monitoring program. The primary objective of the investigation was to generate a broad database, which enables the development of an advanced simulation module for urban drainage modelling. Over 160 field and lab scale experiments have been completed and analyzed for surface runoff and infiltration characteristics. The test series include several pavement types under various boundary conditions such as diverse precipitation impacts, varying surface slope and layer construction as well as different stages of surface clogging and several base and subgrade layer characteristics. The results represent a reliable and comprehensive database that allows profound conclusions and substantial recommendations.     

Degradation of retinyl acetate in simple solvent systems

The degradation of vitamin A acetate was studied by u.v. spectrophotometry in three solvent systems: absolute ethanol, ethanol: water (95:5) and hexanes. Three potential degradative factors were investigated: exposure to light, presence of air and temperature. In all systems studied, exposure to light was the major factor. In the ethanol systems, the rate constants calculated for the degradation in the presence or in the absence of oxygen are not significantly different. Analysis of the data by first order kinetic models yielded the best fit in all cases. The activation energy for the degradation reaction in absolute ethanol was found to be 56 ± 8 kJ/mol. The presence of water in ethanol did accelerate the reaction, but the dependence of the rate on the water content is not a simple one.     

APPLICATION OF SITE-SPECIFIC NATURAL ISOTOPE FRACTIONATION (SNIF-NMR) OF HYDROGEN TO THE CHARACTERIZATION OF EUROPEAN BEERS

More than one hundred samples of European beers have been investigated by the new SNIF-NMR method which is based on 2H NMR at the natural abundance level and enables site-specific natural isotope fractionation factors in ethanol to be determined. The relative (R) and absolute (D/H)_i, parameters are shown to be characteristic of the country where the beers are brewed and the observed variations are explained in terms of cereal composition, water resource, and manufacturing processing (fermentation, yeast, temperature cycle). These new parameters find analytical and mechanistic applications in the identification of a beer and in the investigation of a fermentation process.     

Determination of synthetic growth promoters in bile

To monitor the use of synthetic growth promoting hormones in red meat animals requires a sensitive and rapid method of analysis. This paper describes the development of such a method for these agents in bile, based on a high pressure liquid chromatographic purification procedure with detection and estimation by radioimmunoassay.