Über die statistische Unabhängigkeit der asymptotischen Verteilungsfunktionen inkommensurabler Partialschwingungen

Ohne Zusammenfassung     

Über den Konvergenzbegriff der mathematischen Statistik

Ohne Zusammenfassung     

Zur Lösung von Differentialsystemen mit unendlich vielen Veränderlichen

Ohne Zusammenfassung     

Zur Theorie der beschränkten Bilinearformen

Ohne Zusammenfassung     

Diophantische Approximationen und Hermitesche Matrizen

Ohne Zusammenfassung     

Effect of boundary layer losses on 2D detonation cellular structures

We evaluate the effect of boundary layer losses on two-dimensional H2/O2/Ar cellular detonations obtained in narrow channels. The experiments provide the details of the cellular structure and the detonation speed deficits from the ideal CJ speed. We model the effect of the boundary layer losses by incorporating the flow divergence in the third dimension due to the negative boundary layer displacement thickness, modeled using Mirels’ theory. The cellular structures obtained numerically with the resulting quasi-2D formulation of the reactive Euler equations with two-step chain-branching chemistry are found in excellent agreement with experiment, both in terms of cell dynamics and velocity deficits, provided the boundary layer constant of Mirels is modified by a factor of 2. A significant increase in the cell size is found with increasing velocity deficit. This is found to be very well captured by the induction zone increase in slower detonations due to the lower temperatures in the induction zone.     

Assessments on energy and efficiency calibration of an alpha spectrometry system using standard sources

Studies and evaluations of the main parameters of a high resolution multi-chamber alpha spectrometer and its full calibration using standard sources of ²⁴¹Am, ²³³U and ²⁴⁴Cm are presented for the validation of the complex method of characterization of an alpha spectrometer dedicated for alpha radioactive concentration measurements of various environmental samples. The resolution and efficiency were determined at all possible source-detector distances for all eight solid state ORTEC ULTRA-AS detectors. In addition, the solid angles associated to different measurement geometries and the repeatability of the results were assessed. A detailed inter-comparison of the results was performed drawing important conclusions regarding the quality of the alpha detector response to the alpha radiation of the standard sources used in measurements.