The enthalpy of the reduction of UO2F2 with hydrogen was obtained from quantitative DTA measurements with a linear heating rate and under isothermal conditions, and the thermodynamic data on UO2F, formed as a stable intermediate in the reduction of UO2F2 to UO2, are also presented. The advantages of isothermal DTA in the reduction of U3O8 to UO2 could be demonstrated.
Authors:G. Schuster, G. Braun, K. Henkel, and G. Querner
The variations in the thermoanalytical curves for three differently produced powders of hydrous zirconia are discussed in connection with X-ray measurements and powdermetallurgical characterization. They were shown to characterize the ZrO2-H2O bonding and the thermal treatment for the calcination of hydrous zirconia. They allowed selection of the product with the most favourable microstructure for a high sinter activity, an explanation of the phase formation and phase transformations, and estimations of the energy content of the amorphous material and the thermal stability of the tetragonal phase. It was shown that thermal analysis is an appropriate method for the optimizing of ZrO2-powder production.
Authors:G. Braun, G. Boden, K. Henkel, and H. Rossbach
The direct nitridation of different silicon powders was investigated by thermogravimetry. The chemical composition of the final product, produced unter the optimum nitridation conditions, varied in the region between Si3N3.41 and Si3N3.93, depending on the basic material. The reasons for the incomplete nitridation ratio are discussed.
Authors:K. Yoshihara, M. Hiraga, G. Izawa, and T. Braun
An observation of signals of acoustic emission induced by tritium decay is reported. The equipment consisting of PZT detectors, preamplifiers, low-cut filters and computer evaluation was used in this study as a differential system. The result shows that the two types of clear signals of acoustic emission are induced by tritium decay. They seem to be related to some radiation effects due to tritium irradiation, and not to acoustic waves during tritium decay events.
Authors:Nicole Altvater-Mackensen, Gregor Balicki, Lucie Bestakowa, Bianca Bocatius, Johannes Braun, Lars Brehmer, Verena Brune, Kirstina Eigemeier, Füsun Erdem, Ralf Fritscher, Anne Jacobs, Bernd Klingsporn, Marcin Kosinski, Julia Kuntze, Ju-Ra Lee, Anna Osterhage, Martin Probost, Thorsten Risch, Tobias Schmitt, Wolfgang G. Stock, Anja Sturm, Katrin Weller, and Kerstin Werner
Summary We operationalize scientific output in a region by means of the number of articles (as in the SciSearch database) per year and technology output by means of the number of patent applications (as in the database of the European Patent Office) per priority year. All informetric analyses were done using the DIALOG online-system. The main research questions are the following: Which scientific and technological fields or topics are most influent within a region and which institutions or companies are mainly publishing articles or holding patents? Do the distributions of regional science and technology fields and of publishing institutions follow the well-known informetric function? Are there - as it is expected - only few fields and few institutions which dominate the region? Is there a connection between the economic power of a region and the regional publication and patent output? Examples studied in detail are seven German regions: Aachen, Düsseldorf, Hamburg, Köln (Cologne), Leipzig - Halle - Dessau, München (Munich), and Stuttgart. Three different indicators were used, science and technology attraction of a region (number of scientific articles and patents), science and technology intensity (articles and patents per 1,000 inhabitants), and science and technology density (articles and patents per 1 billion EURO gross value added). Top region concerning both attraction and intensity is Munich, concerning density it is Aachen.