Es wird die Twistorgleichung auf Lorentz-Spin-Mannigfaltigkeiten untersucht. Bekanntermaßen existieren Lösungen der Twistorgleichung auf den pp-Mannigfaltigkeiten, den Lorentz-Einstein-Sasaki Mannigfaltigkeiten und den Fefferman-Räumen. Es wird gezeigt, dass in den kleinen Dimensionen 3,4 und 5 Twistor-Spinoren ohne 'Singularitäten' nur für diese genannten Lorentz-Geometrien vorkommen. Von besonderem Interesse sind Lösungen der Twistorgleichung mit Nullstellen. Es wird die Gestalt der Nullstellenmenge von konformen Vektorfeldern und Twistor-Spinoren beschrieben. Weiterhin wird die Twistorgleichung im Kontext der konformen Cartan-Geometrie formuliert. Als Anwendung werden konform-flache semi-Riemannsche Spin-Mannigfaltigkeiten mit Twistor-Spinoren unter Zuhilfenahme der Holonomiedarstellung der ersten Fundamentalgruppe charakterisiert. Abschließend wird eine Anwendung des Twistorraumes einer Lorentz-4-Mannigfaltigkeit in der Flächentheorie diskutiert. Dabei zeigen wir eine Korrespondenz zwischen holomorphen Kurven im Twistorraum und raumartig immergierten Flächen mit lichtartigem mittlerem Krümmungsvektor. Beispielhaft werden solche Flächen in den Lorentzschen Raumformen der Dimension 4 konstruiert. / The twistor equation on Lorentzian spin manifolds is investigated. Known solutions of the twistor equation exist on the pp-manifolds, the Lorentz-Einstein-Sasaki manifolds and the Fefferman spaces. It is shown that in the low dimensions 3,4 and 5 twistor spinors without 'singularities' appear only for these mentioned Lorentzian spin geometries. Solutions of the twistor equation with zeros are of particular interest. The shape of the zero set of conformal vector fields and twistor spinors is described. Moreover, the twistor equation is formulated in the context of conformal Cartan geometry. As an application the conformally flat semi-Riemannian spin spaces with twistor spinors are characterized by the holonomy representation of the first fundamental group. Finally, we discuss an application of the twistor space of a Lorentzian 4-manifold in surface theory. Thereby, we prove a correspondence between holomorphic curves in the twistor space and spacelike immersed surfaces with lightlike mean curvature vector. Exemplary, such surfaces are constructed in the Lorentzian space forms of dimension 4.

Optical properties of Tl4In3GaSe8, Tl4InGa3Se8, Tl4In3GaS8, Tl2InGaS4 and Tl4InGa3S8 chain and layered crystals were studied by means of photoluminescence (PL) and transmission-reflection experiments. Several emission bands were observed in the PL spectra within the 475-800 nm wavelength region. The results of the temperature- and excitation intensity-dependent PL measurements in 15-300 K and 0.13&times / 10-3-110.34 W cm-2 ranges, respectively, suggested that the observed bands were originated from the recombination of electrons with the holes by realization of donor-acceptor or free-to-bound type transitions. Transmission-reflection measurements in the wavelength range of 400-1100 nm revealed the values of indirect and direct band gap energies of the crystals studied. By the temperature-dependent transmission measurements in 10-300 K range, the rates of change of the indirect band gap of the samples with temperature were found to be negative. The oscillator and dispersion energies, and zero-frequency refractive indices were determined by the analysis of the refractive index dispersion data using the Wemple&ndash / DiDomenico single-effective-oscillator model. Furthermore, the structural parameters of all crystals were defined by the analysis of X-ray powder diffraction data. The determination of the compositional parameters of the studied crystals was done by energy dispersive spectral analysis experiments.

In order to improve the efficiency of various optical surfaces, optical coatings are used. Optical coating is a process of depositing a thin layer of a material on an optical component such as mirror or lens to change reflectance or transmittance. There are two main types of coatings namely / reflective and antireflective (AR) Coatings. Reflective and antireflective coatings have long been developed for a variety of applications in all aspects of use / for optical and electro-optical systems in telecommunications, medicine, military products and space applications. In this thesis, the main properties of reflective and antireflective coatings, the thin film deposition techniques, suitable coating materials for space applications, space environment effects on coating materials and coating design examples which are developed using MATLAB for space applications will be discussed.

No description available.

No description available.

In this article we establish a bridge between dynamical systems, including topological and measurable dynamical systems as well as continuous skew product flows and nonautonomous dynamical systems; and coalgebras in categories having all finite products. We introduce a straightforward unifying definition of abstract dynamical system on finite product categories. Furthermore, we prove that such systems are in a unique correspondence with monadic algebras whose signature functor takes products with the time space. We substantiate that the categories of topological spaces, metrisable and uniformisable spaces have exponential objects w.r.t. locally compact Hausdorff, σ-compact or arbitrary time spaces as exponents, respectively. Exploiting the adjunction between taking products and exponential objects, we demonstrate a one-to-one correspondence between monadic algebras (given by dynamical systems) for the left-adjoint functor and comonadic coalgebras for the other. This, finally, provides a new, alternative perspective on dynamical systems.

The aim of this thesis is to introduce a general framework for what is informally referred to as finite-time dynamics. Within this framework, we study hyperbolicity of reference trajectories, existence of invariant manifolds as well as normal hyperbolicity of invariant manifolds called Lagrangian Coherent Structures. We focus on a simple derivation of analytical results. At the same time, our approach together with the analytical results has strong impact on the numerical implementation by providing calculable expressions for known functions and continuity results that ensure robust computation. The main results of the thesis are robustness of finite-time hyperbolicity in a very general setting, finite-time analogues to classical linearization theorems, an approach to the computation of so-called growth rates and the generalization of the variational approach to Lagrangian Coherent Structures.

Ce travail de recherche a pour but d'apporter des éléments théoriques ainsi que pratiques au débat sur le causes et conséquences de la politisation des deux hauts tribunaux en Colombie, à fin d'enrichir la discussion. Concrètement, cette thèse doctorale analyse la manière dont les hauts juges sont élus et les conséquences les plus visibles de ces processus de sélection. A partir d'une analyse quantitative et qualitative, cette étude explore la façon dont l'autonomie de juges est conditionnée par le processus qu'ils suivent pour être élus. Pour conclure, cette thèse se penche aussi sur l'état actuel du bilan entre l'indépendance des juges et leur responsabilité vis-à-vis de leur fonction. / This researching work intends to provide theoretical and practical elements to enrich the debate about the causes and consequences of the politicization of two high tribunals in Colombia. In fact, this doctoral project analyses the way the election of the high judges is carried out and the respective consequences of these selection processes. Throughout a quantitative and qualitative analysis, we explore the way the autonomy of the judges is conditioned by their election process. Finally, the current state of the assessment between independence and responsibility of the judges is also tackled.

L’armature verte urbaine rassemble tous les éléments de végétation contribuant à répondre aux défis majeurs associés à l’Anthropocène, comme l’adaptation au changement climatique, la préservation de la biodiversité, l’infiltration des eaux pluviales ou l’amélioration de la santé des populations. La cartographie précise des espaces végétalisés urbains fait aujourd’hui défaut bien que les données spatiales issues de capteurs aéroportés soient disponibles depuis de nombreuses années. De ce fait, il est aujourd’hui difficile d’évaluer la fonctionnalité des armatures vertes. Pour répondre à ce besoin d’évaluation, il s’est agi, dans le cadre d’étude de la Métropole de Lyon, de cartographier le territoire à un mètre de résolution spatiale entre 1984 et 2015 en utilisant une procédure orientée objet, et de rendre ces cartographies disponibles sur une plateforme web dédiée. Il en ressort que les surfaces végétalisées de la métropole sont comparables à celles d’autres agglomérations de même rang, mais que l’accès de la population à cette végétation est très inégalement réparti. Par exemple, seuls 11 % des habitants disposent d’un espace vert de plus de 2ha à moins de 5 minutes de chez eux. Souvent sous-estimés dans les politiques urbaines, les jardins des particuliers représentent deux fois la surface des espaces verts publics, et devraient faire l’objet des mêmes questionnements, quant à leur valeur pour la mitigation climatique ou pour la biodiversité. L’évaluation de l’armature urbaine ne s’arrête pas à sa cartographie, mais doit conduire à l’exploration de sa perception à différentes échelles spatiales, pour différents acteurs (habitants, professionnels et autres organismes vivants) et selon plusieurs mesures de bien-être physique, mental et culturel. / The urban green infrastructure brings together all the elements of vegetation that contribute to meeting the major challenges associated with the Anthropocene, such as adapting to climate change, preserving biodiversity, infiltrating rainwater or improving the health of populations. The precise mapping of urban green spaces is today lacking although spatial data from airborne sensors have been available for many years. As a result, it is now difficult to assess the functionality of greeninfrastructures. To meet this need for evaluation, the territory of the urban area of Lyon was mapped at one meter resolution between 1984 and 2015 using an object-oriented procedure. All maps generated were made available on a dedicated web platform. The results show that the green areas of the urban area of Lyon are comparable to those of other agglomerations of the same rank, but that the population’s access to this vegetation is very unevenly distributed. For example, only 11% of the inhabitants can find a green space of more than 2ha closer than a 5 minutes’ walk from home. Often underestimated in urban policies, private gardens make up twice the surface of public green spaces, and should be the subject of the same questions about their value for climate mitigation or the conservation of biodiversity. The evaluation of urban green infrastructures only starts with theirmapping, and should lead to the exploration of its perception at different spatial scales, for different actors (inhabitants, professionals and other living organisms) and according to several measures of physical, mental and cultural well-being.

Im nationalsozialistischem Regime wurde die Arbeitsverwaltung (Reichsarbeitsministerium, Reichsanstalt) zur so genannten Arbeitseinsatzverwaltung ausgebaut. Wesentliches Merkmal dieser Arbeitseinsatzverwaltung war die Schaffung von Sonderbehörden und -instanzen (Reichstreuhänder der Arbeit, Deutsche Arbeitsfront, Vierjahresplanbehörde, Generalbevollmächtigter für den Arbeitseinsatz), die den Arbeitseinsatz effektiver planen, organisieren und leiten sollten. Die Arbeitseinsatzverwaltung war nicht nur verantwortlich für die zunehmende Entrechtung deutscher Arbeitnehmer auf dem Arbeitsmarkt, sondern auch für den millionenfachen Arbeitseinsatz von Fremdarbeiter(innen) und Kriegsgefangenen. Dabei erstreckten sich die Funktionen auf alle Lebens- und Arbeitsbereiche der Fremdarbeiter(innen) (Anwerbung, Deportation, Transport, Lagerunterbringung, Gesundheitsfürsorge, Lohn- und Urlaubsregelungen, Bordellbaracken, Ahndung von arbeitsrechtlichen Vergehen) und auf die Vermittlung von kriegsgefangenen Zwangsarbeitern. Der aufgeblähte Verwaltungskörper der Arbeitseinsatzverwaltung mit zu vielen Kompetenzträgern war indes nicht in der Lage, den eklatanten Arbeitskräftemangel in der deutschen Kriegswirtschaft zu beheben.