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Dissertation
Sustainable diets: Studies on German consumers’ intention-behavior gap
(2020-01)
Globally our practiced food systems are causing great harm to our environment including contributions to biodiversity loss, soil degradation, water pollution, and climate change, as well as to human health. Sustainable diets are crucial for solving those global diet-related problems because they are credited with a key role in the transformation of our currently practiced food systems into more sustainable ones. Increasing the practice of sustainable diets can be a starting point for initiating the needed change. ...
Dissertation
Challenges to ecosystem services of sustainable agriculture in West Africa
(2020)
Food security is still sub-optimal in many parts of West Africa calling for more efficient agricultural practices in mitigating food insecurity. Some of the problems faced in West African agricultural systems are bottlenecks in ruminant livestock supply, inefficiency in commercial poultry production, and loss of arthropod diversity. These issues require proper integration of farming systems, demand the closing of nutrient cycles, need diversi cation of production, and require enhancement of ecosystem services. To ...
Dissertation
Entwicklung einer Robotik-Lösung zur Schneckenbekämpfung in der Landwirtschaft
(2020)
Schnecken sind bedeutende Schädlinge in der Landwirtschaft. Die Ausbringung von Schneckenkorn zur Schneckenbekämpfung als Verfahren nach dem Stand der Technik hat jedoch erhebliche Nachteile. Der Erfolg ist abhängig von der vorherrschenden Witterung und damit unsicher, zudem schadet es auch Nützlingen. Eine Robotik-Lösung zu Schneckenbekämpfung arbeitet wetterunabhängig und ist in der Lage, zwischen Schädlingen und Nützlingen zu unterscheiden.
Durch einen Feldversuch konnte gezeigt werden, dass Überfahrten eines ...
Dissertation
Development of Energy use Profiles, Reduction Concepts, and Implementation of Renewable Energies in the Central Ugandan Pineapple Processing Chains
(2020-02)
Pineapples, like all fruits, are highly perishable and require either immediate consumption or preservation. To make them more stable and add value, four major processing methods are being employed in Uganda, i.e. drying, munaanansi (local drink), wine, and juice making. Energy is one of the main inputs required to achieve any of the processing methods. The aim of this research was to develop energy use profiles, gain insights into energy use reduction options, and to evaluate the applicability of renewable energies ...
Dissertation
Optical Amplification in Disordered Waveguiding Systems
(2020)
Bei dem Phänomen der verstärkten Emission in ungeordneten Systemen handelt es sich um ein wiederentdecktes und über die letzten Jahrzehnte stark debattiertes Themengebiet in der Literatur. Diese Dissertation soll hierzu zwei experimentelle Ansätze bieten, wobei beide in der Lage sind, bei optischer Anregung entweder Random Lasing oder Verstärkte Spontane Emission zu zeigen.
In dieser Arbeit wird thermisch induzierte Faltenbildung (Wrinklebildung) als neuer Ansatz zur Herstellung von Streuzentren in wellenleitenden ...
Dissertation
Die koordinationschemische Ambivalenz zweier mesoionischer Triazoliumaminide
(2020-05)
Die vorliegende Arbeit beleuchtet die Koordinationschemie zweier Mesoionen, die in Abhängigkeit vom angebotenen Zentralatom als N-heterocyclische Carben- (NHC-) oder Amido-Liganden fungieren. Durch Tautomerisierung der Triazoliumaminid-Form zum korrespondierenden Amino-NHC ermöglichen das seit über einem Jahrhundert bekannte analytische Reagenz »Nitron« (1) sowie dessen in dieser Arbeit entwickeltes Alkyl-Homolog 1-tert-Butyl-4-methyl-1,2,4-triazol-4-ium-3-tert-butylaminid (2) einen bequemen Zugang zur Chemie der ...
Dissertation
Fabrication and characterization of diamond nanopillars, waveguides and AFM tips with incorporated color centers
(2020-06)
Diamond is a unique material with outstanding properties and the perfect host for different crystal defects in its lattice, so-called color centers, which provide exceptional spin properties, rendering them a promising platform for the development of novel devices and components in quantum information technologies (QIT) and quantum sensing applications. To overcome diamond's high internal reflection due to its high refractive index, color centers need to be incorporated in photonic diamond structures, leading to ...
Dissertation
Molecular-Frame Angular Distributions of Electrons Emitted by Photoionization and Interatomic Coulombic Decay
(2020)
The continuous refinement of the experimental and theoretical methods to study the electron angular emission distributions, and particularly in a molecule frame of reference, have contributed to a keen understanding of the structure of molecules and have provided deeper insight into fundamental physical phenomena.
Revealing many details of the ionization dynamics, the molecular-frame angular distributions (MFADs) of emitted electrons have been an appealing research topic for the last two decades. Owing to the ...
Dissertation
Energy landscapes and dynamics of magnetic nanostructures: disorder, structure, and magnetic field effects
(2020)
The static and dynamic magnetic properties of two-dimensional ensembles of dipole-coupled magnetic nanoparticles (NPs) are investigated from a theoretical perspective. Particular emphasis is put on the correlations between the geometrical arrangements of the NPs, their inherent structural disorder, and the cooperative magnetic dynamics of the nanostructures as a whole. To this aim a significant number of representative two-dimensional NP ensembles with different structural geometries and degrees of disorder are ...
Dissertation
Explicit Description Of Isogeny And Isomorphism Classes Of Drinfeld Modules Of Higher Rank Over Finite Fields
(2020)
When jumping from the number fields theory to the function fields theory, one cannot miss the deep analogy between rank 1 Drinfeld modules and the group of root of unity and the analogy between rank 2 Drinfeld modules and elliptic curves. But so far, there is no known structure in number fields theory that is analogous to the Drinfeld modules of higher rank r ≥ 3. In this thesis we investigate the classes of those Drinfeld modules of higher rank r ≥ 3 defined over a finite field L. We describe explicitly the Weil ...