Zum elastisch-plastischen Behälter mit nichtlinearer Verfestigung

Zusammenfassung Gegenstand der Untersuchung ist der elastisch-plastische Kugel-und Zylinderbeh?lter mit nichtlinearer Verfestigung unter Innendruck. Für vier spezielle Verfestigungsgesetze lassen sich die in der Beh?lterwand auftretenden Spannungen, Verschiebungen und plastischen Dehnungen in geschlossener Form ermitteln. Die Behandlung des Zylinderbeh?lters gründet sich auf die Trescasche Flie?bedingung und die zugeordnete Flie?regel. Die vorliegende Forschungsarbeit wurde im Studienjahr 1987/88 w?hrend der GastprofessurU. Gamers am Department of Mechanical Engineering der Middle East Technical University durchgeführt.     

Structure optimization of neural networks with the A*-algorithm

A method for the construction of optimal structures for feedforward neural networks is introduced. On the basis of a construction of a graph of network structures and an evaluation value which is assigned to each of them, an heuristic search algorithm can be installed on this graph. The application of the A*-algorithm ensures, in theory, both the optimality of the solution and the optimality of the search. For several examples, a comparison between the new strategy and the well-known cascade-correlation procedure is carried out with respect to the performance of the resulting structures.     

Kinetik und Reaktionstechnik der anaeroben Abwasserreinigung

Kinetics and reaction engineering of anaerobic sewage treatment. In numerous papers the reaction rate of acetic acid metabolism by methanogenic bacteria, which is frequently suspected as the slowest step in anaerobic digestion, is described by Monod kinetics using total acetic acid concentration as the substrate for catabolism. However, in some papers the authors try to include the influence of pH by using only the un-ionized acetic acid as the substrate in a Haldane-kinetic term taking substrate inhibition into account. From this viewpoint, some conclusions regarding reaction engineering aspects of anaerobic waste water treatment are drawn and simple models for the conventional and for the contact process are discussed. The advantage of using support materials for anaerobic bacteria is shown. The space loading can be increased in a two step cascade of fixed bed reactors with external loops for water recycling, with the system being filled with synthetic foam particles as support.     

Situations, attributions, and the evaluation of reactions.

The present studies deal with the integration of theoretical models and empirical work on the antecedents of causal attributions with conceptions about attributional consequences. A central, although thus far neglected, postulate of attribution is addressed: the assumption that realistic attributions lead (or, more specifically, are perceived as leading) to functional behaviors and emotions. First, definitions of veridicality and functionality are discussed within an attributional framework. Second, three simulation studies that investigate whether realistic attributions are perceived as leading to functional reactions were conducted. Results indicated that stimulus persons who are described as exhibiting behaviors that are guided by unrealistic attributions are judged to be less likely to attain long-range success in both achievement and social situations and are thought of as being less contented and less likeable than persons who show reactions that are tied to realistic attributions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Efficacy of nutritional supplements used by athletes

Findings on the efficacy of nutritional supplements used by athletes are reviewed. Many athletes have turned away from anabolic steroids and toward nutritional supplements in the hope of gaining a competitive edge without threatening their health. Athletes may require slightly more protein than sedentary people do to maintain positive nitrogen balance, but it is dubious whether extra dietary protein will help someone to achieve athletic goals. Purified amino acids have become a popular if expensive form of protein supplementation; there is no scientific evidence, however, to support their use. Excessive protein supplementation can lead to dehydration, gout, liver and kidney damage, calcium loss, and gastrointestinal effects. Supplementation with vitamins and minerals in excess of recommended daily allowances appears to have no effect on muscle mass or athletic performance. Other substances touted as having ergogenic properties are carnitine, cobamamide, growth hormone releasers, octacosanol, and ginseng; again, there is no reliable scientific evidence to support claims that products containing these compounds have ergogenic potential, and heavy supplementation may lead to adverse effects. Nutritional supplements are promoted through unsubstantiated claims by magazine advertisements, health food stores, coaches, and other sources. The FDA considers nutritional supplements to be foodstuffs, not drugs, and therefore has not required that they be proved safe and effective. Dosage guidelines are inadequate, and quality control is poor. The FDA has begun to revise regulations governing labeling and health claims for these products. There is little if any evidence that nutritional supplements have ergogenic effects in athletes consuming a balanced diet, and some products have the potential for harm.