Explosive hydrogen burning during type I X-ray bursts

Explosive hydrogen burning in type I X-ray bursts (XRBs) comprise charged particle reactions creating isotopes with masses up to A~100. Since charged particle reactions in a stellar environment are very temperature sensitive, we use a realistic time-dependent general relativistic and self-consistent model of type I x-ray bursts to provide accurate values of the burst temperatures and densities. This allows a detailed and accurate time-dependent identification of the reaction flow from the surface layers through the convective region and the ignition region to the neutron star ocean. Using this, we determine the relative importance of specific nuclear reactions in the X-ray burst.Comment: 53 pages, 24 figures, submitted to Astrophys.

Kurt Mothes - 70 Jahre

kein Abstract vorhandenno abstract availabl

Design of State Plane Trajectory Control for a Soft Switching AC-Link DC-DC Converter

The objective of this work is to present the controller operation and mathematical analysis of the AC-link dc-dc converter, a parallel resonant converter, for which state plane trajectory control (SPTC) is proposed. The contribution is an autonomous control technique achieving the benefits of bidirectional power flow, soft switching, and converter switching at its natural resonant frequency as opposed to conventional forced control operations. The switching sequence is implemented using an autonomous state machine triggered by the voltage and current state variables of the resonant LC tank, transitioning between modes of operation strategically to achieve said benefits. By using state plane analysis techniques, the dynamics of the resonant tank can be seen visually, and the trajectories can serve as information to control the converter. All results were simulated in MATLAB/Simulink utilizing the PLECS blockset. In addition, an electrical characteristic study was performed in ANSYS Simplorer on the electrical components to measure the efficiency and thermal response of the semiconductor devices

De Natura arte et remediis

Originaal Greifswaldi Ülikooli raamatukogus, avaldatud valdaja loa

Zu den Blättern der Chronik von Riga : am Schlusse des 1806ten Jahres

http://www.ester.ee/record=b4009308*es

De empyemate ut sequela pleuritidis : dissertatio inauguralis medica

http://tartu.ester.ee/record=b1921580~S1*es

Spent Yeast from Brewing Processes: A Biodiverse Starting Material for Yeast Extract Production

Spent yeast from beer manufacturing is a cost-effective and nutrient-rich starting material for the production of yeast extracts. In this study, it is shown how physiologically important ingredients in a yeast extract are influenced by the composition of the spent yeast from the brewing process. In pilot fermentations, the time of cropping (primary fermentation, lagering) of the spent yeast and the original gravity (12 ˚P, 16 ˚P, 20 ˚P) of the fermentation medium was varied, and four alternative non-Saccharomyces yeast strains were compared with two commercial Saccharomyces yeast strains. In addition, spent yeast was contaminated with the beer spoiler Lactobacillus brevis. The general nutrient composition (total protein, fat, ash) was investigated as well as the proteinogenic amino acid spectrum, the various folate vitamers (5-CH3-H4folate, 5-CHO-H4folate, 10-CHO-PteGlu, H4folate, PteGlu) and the biological activity (reduction, antioxidative potential) of a mechanically (ultrasonic sonotrode) and an autolytically produced yeast extract. All the investigated ingredients from the yeast extract were influenced by the composition of the spent yeast from the brewing process. The biodiversity of the spent yeast from the brewing process therefore directly affects the content of physiologically valuable ingredients of a yeast extract and should be taken into consideration in industrial manufacturing processes