Books published by Fraunhofer IRB Verlag

In this work, mathematical models for combined depth and cake filtration are developed. Their formulation is either based on a moving or free boundary description. For the free boundary model existence and uniqueness of the solution is shown. To study the influence of the model parameters, two different tools are introduced, namely model reduction and parameter identification. Model reduction is used to study the sensitivity of the parameters and to accelerate the solution procedure. Multiple ways to construct a projection basis are discussed and reviewed. For parameter identification, an optimization framework for the free boundary problem is derived. Therefore a gradient algorithm in combination with an adjoint formulation is used. The models are compared to several experimental data and different mathematical aspects of the problem are tested, too. The results show that it is possible to reproduce the experimental data. It is further shown that a nonlinear pressure drop, often arising in cake filtration, can be explained by the model without considering compression of the cake.

The scope of this work is to investigate and to develop advanced HIPIMS processes for deposition of oxides, utilizing industrial-scale equipment and technology. Two classes of oxide materials were studied: insulating (aluminum oxide) and conducting oxides (indium-tin oxide and aluminum-doped zinc oxide). The electrical properties of the oxides have a significant influence on the process design, as the issues and approaches for deposition of insulating materials are fairly different from conducting materials. Different types of reactive process control were also investigated, utilizing optical emission spectroscopy to control the oxygen flow and lambda probes to control the discharge power. A non-reactive process was also studied for indium-tin oxide.

Electrochemical processes to form the metallization of high efficient silicon solar cells are developed. Direct metal plating on silicon, aluminum and indium tin oxide is investigated. This book deals with Electrochemical processes.

The highly accurate performance evaluation of photovoltaic devices has never been more important given the progress in photovoltaics. In this thesis, a spectral responsivity measurement set-up based on ultrashort laser pulses is developed that provides substantial reductions of measurement uncertainties.

Investigates several methods for the design of a pitch control system, which actively reduces the fatigue loads on the tower of a wind turbine. This work demonstrates that it is possible to design collective pitch controllers that allow to reduce the fore-aft tower bending loads due to 3p harmonic excitation.