Vergleich von Nachweisverfahren für Stutzen in Zylinderschalen unter Innendruck und äußeren Lasten

Various methods for the verification of nozzles in cylindrical shells are described and the results of an example are compared. The example is carried out according to DIN EN 13445‐3, Sect. 16.5, in which the maximum permissible loads from internal pressure, axial force as well as moments in the longitudinal and circumferential direction are calculated. The results are compared with finite element computations performed with a 3D shell model, both with linear‐elastic material behavior and as limit‐load analyzes with ideal‐elastic ideal‐plastic material behavior.     

Desaktivierungsverhalten von Arenen und Heteroarenen. XXXI [11]. Ein Modell für die reversible Photodimerisierung von Anthracen und 9-Methylanthracen

Deactivation Behaviour of Arenes and Heteroarenes. XXXI. A Model of the Reversible Photodimerization of Anthracene and 9-Methylanthracene Starting from the Woodward-Hoffmann state diagram of the reversible photodimerization of anthracene and 9-methyl-anthracene the potential correlation diagram is shown due to an excimer formation. This qualitative diagram is fixed by ten values of the state potential, which are determined directly or indirectly, respectively, by variation of the influence of environment. The mechanism and the kinetics of the photoreaction are discussed on the basis of the given potential correlation diagram and for the reversible photodimerization a common pericyclic transition state is assumed. The photochemical dimerization is a pure diabatic reaction. The photochemical decomposition of the dimer occurs mainly diabatic, and the quantum yield of the adiabatic excimer formation is only about the twentieth part of those of the diabatic reaction.     

Logistikzentren für die Kunststoffindustrie

Logistics Centers for the Plastics Industry The capacity of reactors and extruders for the production of polymers is growing steadily. New catalysts and reactor modifications allow significant improvement of the performance of existing plants. At the same time the proportion of plastics that is sent in bulk to processors, rather than packed in sacks directly to the customer, is increasing globally. The various delivery demands and the storage of pellets define a series of possibilities for the design of logistic centers. An optimal design can only be achieved through close collaboration and agreement with specialized companies so that the needs and procedures of the operation can be fulfilled. Good design and planning can lead to a reduction of the operating costs or an increase of the dispatch capacity per employee of up to 30 %.