Böcker utgivna av Cuvillier

Der deutsche Strommarkt unterliegt durch den zunehmenden Anteil der Stromerzeugung aus Erneuerbaren Energien einem fundamentalen Wandel. Von zentraler Bedeutung ist der Merit-Order-Effekt, der die Verdrängung konventioneller Stromerzeugung und damit einhergehende Preisminderungseffekte beschreibt. In der vorliegenden Arbeit werden in diesem Zusammenhang grundlegende Preiszusammenhänge des Großhandelsmarktes unter Berücksichtigung der Stromerzeugung aus Wind und Photovoltaik analysiert. Dies erfolgt zum einen über Paneldaten-Modelle, zum anderen werden über Zeitreihenmodelle Kurzfristprognosen erstellt. Dabei werden die folgenden Kernfragen der Arbeit thematisiert: Was ist der aktuelle Stand der wissenschaftlichen Forschung im Bereich Zeitreihenanalyse auf Großhandelsmärkten für Strom? Welche Zeitreihenmodelle weisen die beste Prognosequalität auf? Und: Welche Preiseffekte hat die Stromerzeugung aus Erneuerbaren Energien? Die Beantwortung erfolgt über umfangreiche Literaturanalysen und empirische Studien.

In recent years, Silicon Photomultipliers (SiPMs) developed into mature photon detectors which are chosen in a wide field of applications. However, the dark count rate (DCR) of SiPMs sets strong limitations to such detector systems. This quantity describes the rate at which pulses are generated in the absence of light (dark pulses) and deteriorate the photon counting performance of SiPMs.In the course of the presented research, two innovative characterization methods were developed for the identification and evaluation of the physical effects which underlie the generation of dark pulses in SiPMs.The first method is based on the temperature dependence of the DCR. It allows for the extraction of different contributions to the dark count rate, which (a) depend on the applied voltage, (b) depend on the applied overvoltage and © are quasi-independent of the electric field. The second method is based on the detection and mapping of the light intensity which is emitted by the effect of hot carrier luminescence during the avalanche breakdowns of SiPM micro-cells. This method enables a sub-micro-cell, 2D spatially resolved measurement of the dark count rate within the plane of the active area. In particular, the individual contributions of implantation and radiation induced defects to the DCR were evaluated via this method.The acquired knowledge was used to successfully suppress the dark count rate of KETEK SiPMs down to a level of 40 kHz/mm².

BeschreibungGases have to be specifically mixed with a continuous liquid phase to perform a reaction with high yield and selectivity. The time scales of mixing are determined by the transport processes in the boundary layer close to the phase boundary and by bubble swarm turbulence. For clarification of the local mass transfer in bubbly flows, an experimental setup is developed and successfully used to investigate single rectilinear (spherical), helical (ellipsoid) and irregular rising bubbles with and without chemical reaction. Therefore, the time resolved scanning laser induced fluorescence technique is further developed and applied for the first time to bubbly flows to allow new insights in the mass transfer processes.

As digitalization has caused major changes within various traditional industries, firms are forced to explore new technological paths and access knowledge beyond their boundaries. This dissertation focuses on knowledge provided by startups. Besides introducing search approaches and successful search strategies to identify startups, this work also provides insights into how corporations may become attractive partners for startups. In addition, the quality of startup ideas is compared with ideas originating from established suppliers. Finally, this dissertation examines the implications of engaging with startups

The natural behavior of pigs is adapted to very complex environments and is characterized by a high proportion of exploratory behaviour. In modern, intensive husbandry systems, the behaviour pigs would show in natural environments cannot be expressed to the degree that is necessary for the animals to maintain a positive emotional state. Health and behaviour problems arise in intensive pig husbandry, leading to stress and negative emotional states in the animals. This animal welfare problem fuels growing concerns of the public. As negative emotional states, such as stress, are more intensely expressed and potentially life threatening, they are easier to study. The expression of positive emotion, even though it is expressed more subtle, is no less important. This study was therefore conducted with the objective to identify, elicit and measure behavioural and physiological indicators of positive emotion in pigs. With the ability to facilitate a positive emotional state, the welfare of pigs kept in intensive livestock production systems can be greatly improved.

Thermal barrier coatings (TBCs) are ceramic coating systems developed to reduce the heat transfer from a hot medium to the coated parts. This technology can be used in automotive exhaust systems to reduce the heat transfer from the exhaust gases to the metal pipes. As a result, catalytic converters can reach the ideal temperature for the conversion of gases more quickly, reducing emissions. In order to be effective, coatings must be applied to the inside of pipes. However, conventional techniques for the preparation of ceramic coatings are not suitable for the deposition of coatings inside of long pipes with small diameter, or are too expensive. In this work, a TBC system was developed using the polymer-derived ceramics (PDC) technique. In this method, ceramic coatings are obtained by the thermal conversion of preceramic polymers into ceramics, after deposition of the coatings by simple lacquer techniques. Fillers are used to tailor the microstructure and the properties of the coatings. This book contains a review of the literature on PDC coatings, the procedures for the preparation of the TBCs, as well as their properties.

In the present work, both in silico and in vivo methods for flux analysis in plants were successfully developed and applied for enhanced understanding of plant physiology. Taken together, the in silico metabolic simulations provide detailed molecular insights into plant functioning, particularly by linking in vivo with in silico data. The knowledge gained from such a systems-biological approach, together with the proposed high potential of plants as biotechnological production platforms, especially for compounds requiring much redox power, will help to establish plants as biotechnological factories.For the first time, the in vivo metabolism of an agriculturally relevant crop, O. sativa, was investigated, through non-stationary 13C-metabolic flux analysis. This allowed elucidation of the in vivo intracellular carbon partitioning in rice plants and of the plants' necessity for futile cycling of resources, thus, contributing significantly to our current knowledge on plant metabolism. In addition, the effect of imazapyr, an industrially relevant herbicide, on rice metabolism was inspected using the newly established workflow. This first real-life case-study provides a valuable proof-of-principle and enabled a deeper understanding of the immediate metabolic effects of the treatment. This method can now be adopted to other crops, cell lines and stress inducers, such as abiotic stresses, herbicides and fungicides, and therefore, has great potential in green biotechnology.