Reports

All over the world, research and development programs concentrate on new propulsion systems for passenger cars with PEM-Fuel Cell (Proton Exchange Membrane) systems, hydrogen production unit on-board, and electric motor. The objectives of this thesis are the investigation of the dynamic methanol-reformer behavior and simulation calculations of the fuel-cell powered propulsion system [...]

The understanding of the behaviour of charged marcromolecules, or polyelectrolytes, is still very poor. Nevertheless, polyelectrolytes are of great technical and scientific interest; e.g [...]

Two recently completed conceptual design studies for high power spallation sources (ESS in Europe (1) and NSNS in the United States (2)) identified several topics where R&D work is necessary in order to further optimize the design with respect to performance, availability and costs of the facilities. In the target/reflector/moderator area, materials issues were given high priority since they determine the lifetime of most of the target components [...]

Methods for the direct analysis of nonconducting materials have become more and more important in recent years. These requirements are mainly the result of the development of materials for new or improved technical applications [...]

The fabrication process of a light emitting diode (LED)-array with porous silicon (PS) was investigated. The fundamental idea was to control the electroluminescence (EL) of a continuous PS-layer locally by an array ofvertical metal-semiconductor-feld-effect-transistors (MESFETs) based on single crystalline Si/CoSi$_{2}$/Si(100)-heterostructures [...]

Hydrogen-powered low-temperature fuel cells (PEFC) are the energy conversion units in vehicles with methanol as energy carrier and apowertrain consisting of the following main units: Methanol reformer (Hrproduction) including catalytic converter, gas treatment, PEFC with peripheral units, electric motor with electric controllers and gearbox. The process engineering analysis is based on a simulation model (PROfil, SIMSCI) and describes the energy and water management as a function of different assumptions as well as operating and ambient conditions for net electricity generation in a PEFC-powered powertrain [...]

The influence of Si and Ti additions on the oxidation behaviour of Ni-20Cr-IOAl-Y protective cladding aUoys has been investigated. The Si and Ti contents in the model alloys were varied systematicall and the influence on the early oxidation stages as well as on the long-term oxidation was determined in the temperature range 950°C - 1100°C in Ar-20%O2 [...]

High temperature proton conductors are candidate materials for solid electrolytes in different applications like sensors or fuel cells. Non-stoichiometric compounds likeBaCa$_{0.393}$Nb$_{0.607}$O$_{3-8}$ or BaCe$_{0.9}$Y$_{0.1}$O$_{3-8}$ show considerable water uptake and subsequent proton conductivity after exposure to wet atmospheres. [...]

This work deals with the electromagnetic interaction in relativistic heavy ion and proton-proton collisions. The underlying theory is based on the equivalent photonapproximation (EPA). [...]

Several passive safety systems for a new innovative boiling water reactor (BWR) are investigated experimentally and analytically within the framework of the European research programme "European BWR R&D Cluster for Innovative Passive Safety Systems". One of these passive safety systems is the building condenser (BC) which is foreseen for the passive decay heat removal from the containment of the new SWR 1000 reactor designed by Siemens AG [...]