Zuverlässigkeitsorientierte Bewertung von Bauwerken auf Grundlage der Bauwerksüberwachung

Reliability‐based system assessment of civil engineering structures based on structural health monitoring The safety and usability of transport infrastructure is of great importance for the entire society, because disturbances of traffic networks can have significant financial and environmental consequences. Especially in times when bad news about deteriorated structures and shortened public budgets are omnipresent, innovated solutions are in demand. Structural health monitoring (SHM) can help to assess the safety of deteriorated structures. With the help of suitable monitoring strategies the service life, which may elapse up to a renovation or a renewal without endangering the users, can be determined. So far however a regular monitoring of buildings – with few exceptions – did not become generally accepted yet, above all because it is time‐consuming and expensive. Owing to world‐wide research and development in this field however inspection and monitoring strategies can be optimized meanwhile in such a way becoming attractive for various applications. Innovative methods for structural health monitoring (SHM) are developed by the Collaborative Research Centre (CRC) 477 at the Braunschweig University of Technology. In project field A1 a framework for the probabilistic safety assessment of structures based on data from SHM is developed. This paper describes and explains the methodology of the framework and shows its application using a substitute structure of the CRC 477 as an example.     

Key processes of client participation in psychotherapy: Chronography and narration.

Six clients' participation in therapy was rated at the utterance level on 34 interactional categories. A primary and secondary sample consisted of one session randomly drawn from the early, middle, and last 3rd of each therapy. P-technique factor analysis of these chained samples of client speech reveals 4 key client factors (Continuing Objective Information Exchange, Performing Painful Self-Formulating Work, Negotiating the Therapeutic Relationship, and Depicting Nonsignificant Others, Client Occupation, and Leisure). Multivariate analyses reveal significant client by session interactions on all 4 factors. Chronographs of client factor scores were interpreted and linked to the verbatim texts, revealing clinically meaningful client episodes. It is concluded that P-technique can help to integrate quantification of therapy processes with their clinical interpretation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functionalized polyisobutenes by SH-en addition

Low molecular weight polyisobutenes can be transformed into macromonomers by means of SH-en addition, provided that the thiols contain an additional hydroxy group. The product structures formed by free-radical or electrophilic addition reactions can be determined on model compounds as well as on the polymers by ¹H- and ¹³C-NMR spectroscopy.     

Recrystallization of bacterial S-layers on flat polyelectrolyte surfaces and hollow polyelectrolyte capsules

Polyelectrolyte multilayer (PE) deposition and S-layer technology have been combined to make novel robust biomimetic surfaces and membranes. Isolated subunits of the bacterial cell surface layer from Bacillus sphaericus CCM2177 SbpA was self-assembled on PE multilayer supports, with the composition of the multilayer playing a crucial role in determining the structure of the resulting supported protein layers. Flat substrates were studied using atomic force microscopy and neutron reflectometry; protein on suitable PE combinations showed a crystalline structure with lattice constants equal to those found in vivo on bacterial surfaces. The mechanical stability of the S-layer is higher when recrystallized on PEs than directly on silicon supports. The recrystallization process was subsequently used to coat colloidal particles, permitting the determination of zeta potentials before and after coating. Hollow capsules could also be coated in the same way, as proven by various techniques. Our results suggest that electrostatic interactions via divalent cations are important for the assembly process. The results also demonstrate that the versatility of the PE multilayer membranes can be successfully combined with the well-defined surface chemistry and structure of 2D protein crystals.     

Fixed-Point Logics and Solitaire Games

The model-checking games associated with fixed-point logics are parity games, and it is currently not known whether the strategy problem for parity games can be solved in polynomial time. We study Solitaire-LFP, a fragment of least fixed-point logic, whose evaluation games are nested soltaire games. This means that on each strongly connected component of the game, only one player can make nontrivial moves. Winning sets of nested solitaire games can be computed efficiently. The model-checking problem for Solitaire-LFP is Pspace-complete in general and Ptime-complete for formulae of bounded width. On finite structures (but not on infinite ones), Solitaire-LFP is equivalent to transitive closure logic. We also consider the solitaire fragment of guarded fixed-point logics. Due to the restricted quantification pattern of these logics, the associated games are small and therefore admit more efficient model-checking algorithms.     

Phosphine from rocks: mechanically driven phosphate reduction?

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.     

Biological treatment of effluents from a coal tar refinery using immobilized biomass

An airlift-loop reactor with a fluidized bed was used for the microbiological removal of a complex mixture of aromatic substances originating from coal tar process waters. A specially adapted mixed microbial culture derived from several soil and sludge samples was immobilized on fluidized sand particles and retained in a reactor at high biomas concentrations of 3 to 16 g dry matter per liter, depending on the COD-load. In a two-stage pilot plant, those aromatic substances which passed through the first stage either unaltered or only partially oxidized were effectively eliminated by the immobilized biomass in the second stage. Whereas most of the waste water components such as phenols and quinoline were already degraded by a conventional activated sludge system in the first stage, the majority of nitrogen-containing aromatic bases could be sufficiently eliminated with specially adapted micro-organisms in the second stage. Although the COD-feed load was increased to 12 and 15 kg m^?3 d^?1 in the first and second stages, respectively, it was removed to the extent of 87% on the average with an overall residence time varying between 11.5 and 29 h.