Ein Stoffdaten-Informationssystem für die Chemische Technik

A physical property data bank for chemical engineering . DETHERM , a data bank for physical property data of chemical compounds and mixtures as required by chemical engineers is described, which allows the retrieval of literature data, the algebraic manipulation of retrieved data, data calculations and estimations, data analysis, and connection with data processing systems. In the data bank both numerical and non-numerical data are stored, data and substances being labeled by ?tags”? which characterize the kind of stored data and substances.     

Integrated Circuits for Broad-Band Communications Systems

Integrated circuits for broad-band communication systems which enable broad-band communication between subscribers require LSI's with a performance concerning speed, complexity, and power dissipation which cannot be fully met by present semiconductor technologies. The requirements for coders and decoders, line transmission circuits, and broad-band switching network elements depend upon the system concept chosen. For one chosen system concept, these requirements are derived. By using a representative model for the development of the demand, characteristic curves for the demand of subscriber-line circuits and for central unit elements are resulting. From these curves the optimum semiconductor technologies, complexities, and design strategies are derived. It can be assumed that the results are rather independent of variations of system concept and introduction models.     

Investigations of gas-particle-lance flows at high velocity for the injection of solid in melting baths

For the injection of gas and solid into molten masses using lances the situation at the lance outlet is a boundary condition for the mixing in the melting bath and therefore an important parameter for the energy and mass exchanges which take place there. In the scope of the main research programme of the Deutsche Forschungsgemeinschaft named “Mischung mit Energie-und Stoffumsatz in schmelzmetallurgischen Systemen”, a mathematical model is to be developed at the Institut für Energieverfahrenstechnik der Technischen Universität Clausthal, which should make it possible to calculate the situation at the outlet of a lance operating with gas and solid, using operational and geometrical parameters (pressure at lance intake, amount of solid, length and diameter of lance) which can be freely chosen.     

Mechanical damage to Gram-negative bacteria by surface plating with the Drigalski-spatula technique

Colony counting by spreading bacterial suspensions on plating media by various techniques is of general concern. Comparative studies between hand plating (Drigalski-spatula technique) for different time intervals and spiral plating resulted in significant differences in colony counts. Lower counts of Gram-negative bacteria were obtained by using hand plating for more than 10 s, compared with short time hand plating (5 s) or spiral plating. Colony counting of Gram-positive bacteria showed no differences between both techniques. Further characterisation of Escherichia coli cells spread with the Drigalski-spatula technique by electron microscopy revealed a large number of damaged cells compared to control samples. The data clearly shows that the mechanical forces during hand plating are sufficient to damage E. coli cells.