Locking-free DGFEM for elasticity problems in polygons

The h-version of the discontinuous Galerkin finite element method(h-DGFEM) for nearly incompressible linear elasticity problemsin polygons is analysed. It is proved that the scheme is robust(locking-free) with respect to volume locking, even in the absenceof H²-regularity of the solution. Furthermore, it is shown thatan appropriate choice of the finite element meshes leads torobust and optimal algebraic convergence rates of the DGFEMeven if the exact solutions do not belong to H².     

Computer model of the formation of self-organizing systems

A model of a simple self-organizing system is investigated. Mechanisms that are important to a molecular-biological understanding of evolution are studied with the aid of the model.     

Natural products in combinatorial chemistry: an andrographolide-based library

The generation of a natural-product-based library starting from andrographolide is described. Utilizing andrographolide itself in parallel solution-phase synthesis leads to a 360-membered library. The initial transformation of the starting material via ozonolysis is followed by the conversion into a suitable template by introduction of a thiazole moiety. Subsequent decoration at two points of diversity yields the desired natural product derivatives. The selection of actually synthesized compounds is based on a virtually generated library and the assessment of its members with respect to physicochemical parameters, thus ensuring pharmacological relevance of the compounds.     

Locking-free adaptive discontinuous Galerkin FEM for linear elasticity problems

An adaptive discontinuous Galerkin finite element method for linear elasticity problems is presented. We develop an a posteriori error estimate and prove its robustness with respect to nearly incompressible materials (absence of volume locking). Furthermore, we present some numerical experiments which illustrate the performance of the scheme on adaptively refined meshes.

     

An hp-Adaptive FEM Procedure based on Continuous Sobolev Embeddings

Suitable continuous Sobolev embeddings are applied in order to derive smoothness estimators for adaptive hp-refinements in the context of hp-finite element methods. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Thermischer Abbau von Polysulfonen

Ohne ZusammenfassungMit 10 Abbildungen in 16 Einzeldarstellungen und 5 Schemata     

Adsorption and displacement of beta-2-microglobulin at solid/liquid interfaces

Adsorption of beta-2-microglobulin from aqueous solution onto unmodified and methylated silicon wafers and subsequent displacement of the small globular protein by fibrinogen were studied by spectroscopic ellipsometry, immunosorbent assays and atomic force microscopy. The results provide evidence that hydrophobicity of the substrate increases the maximum adsorbed amount of beta-2-microglobulin and the resistance of the adsorbed protein to displacement from the interface by competing species, respectively. Further, the dynamics of beta-2-microglobulin adsorption was found to induce significant differences in the degree of displacement achieved at given conditions. The observed variations in displacement behavior of adsorbed beta-2-microglobulin were interpreted based on information on the layer structure gained by atomic force microscopy. More compact and relatively smooth protein layers were formed on the hydrophobic surface corresponding to lower displacement by fibrinogen.     

The role of radicals in the Belousov-Zhabotinsky reaction

A new theory of the Belousov-Zhabotinsky (BZ) reaction, the Radicalator model, is presented. This model is based on a negative feedback loop involving a fast reaction between malonyl and bromine dioxide radicals. Experimental evidence for the validity of the model is given for BZ systems in 3 M and 1 M sulfuric acid solution.