Nonlinear modeling of hysteretic systems with double hysteretic loops using position and acceleration information

This paper presents two new dynamic hysteresis models obtained from the Bouc–Wen model by incorporating position and acceleration information. On the one hand, the model employing position information is rate-independent and it is able to reproduce some kind of double hysteretic loops unable to be reproduced with the original Bouc–Wen model. On the other hand, the model employing acceleration information is insensitive to linear time-scale variations. Moreover, a classification of the BIBO-stable models has been derived for both position and acceleration cases. Double hysteretic loops have been experimentally reported in shape-memory alloys, reinforced concrete structures, wood structures and lightweight steel shear wall structures. The proposed hysteretic models represent a prominent use in the field of structural dynamics and earthquake engineering because they can capture the nonlinear dynamics of the materials and structures presented earlier when they are subjected to dynamic loads as earthquake excitations.     

Transient dynamic investigation of nonlinear 3D soil–structure interaction problems using an iterative coupling approach

A domain decomposition approach for the transient analysis of arbitrary three-dimensional soil–structure interaction problems is presented. The coupling of the subdomains is performed in an iterative manner. For this purpose, a sequential as well as a parallel interface relaxation algorithm have been developed, where the coupling iterations are performed very effectively together with the iterations which are required to solve the nonlinear FEM system of equations. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia inhibition.     

Deconfinement transition in three-dimensional compact U(1) gauge theories coupled to matter fields

It is shown that permanent confinement in three-dimensional compact U(1) gauge theory can be destroyed by matter fields in a deconfinement transition. This follows from a nontrivial infrared fixed point caused by matter, and an anomalous scaling dimension of the gauge field. This leads to a logarithmic interaction between the defects of the gauge fields, which form a gas of magnetic monopoles. For logarithmic interactions, the original electric charges are unconfined. The confined phase, which is permanent in the absence of matter fields, is reached at a critical electric charge, where the interaction between magnetic charges is screened by a pair-unbinding in a Kosterlitz-Thouless-like phase transition.     

Smaller and faster: the 20-residue Trp-cage protein folds in 4 micros

We have used laser temperature jump spectroscopy to measure the folding speed of the 20-residue Trp-cage, the smallest polypeptide known to exhibit truly cooperative folding behavior. The observed folding time (4 mus at room temperature) makes this not only the smallest foldable protein, but also the fastest, with a folding speed that exceeds contact-order predictions and approaches anticipated diffusional "speed limits" for protein folding.     

Als Beitrag zur qualitativen Unterscheidung von Netz- und Waschmitteln

Ohne Zusammenfassung     

Die Bestimmung von Propylen in ?thylen-Propylen-Copolymeren mit Hilfe der Infrarotspektroskopie

Ohne Zusammenfassung     

Die Verwendung von Benzoes?ure als Extinktionsstandard bei der IR-Spektroskopie in pharmazeutischen Analysen

Ohne Zusammenfassung