Submitted by Dilene Paulo (dilene.fatima@ufcg.edu.br) on 2018-02-07T13:41:46Z No. of bitstreams: 1 VERA SOLANGE DE OLIVEIRA FARIAS – TESE PPGEP 2011.pdf: 7179434 bytes, checksum: 4a30c9a95f4a089e00fa550fbf1b42b8 (MD5) / Made available in DSpace on 2018-02-07T13:41:46Z (GMT). No. of bitstreams: 1 VERA SOLANGE DE OLIVEIRA FARIAS – TESE PPGEP 2011.pdf: 7179434 bytes, checksum: 4a30c9a95f4a089e00fa550fbf1b42b8 (MD5) Previous issue date: 2011-04-29 / CNPq / Este trabalho apresenta a solução numérica da equação de difusão tridimensional em regime transiente, para um domínio arbitrário. Para atingir os objetivos, a equação de difusão foi discretizada usando coordenadas generalizadas via método dos volumes finitos com uma formulação totalmente implícita, para condições de contorno de equilíbrio e convectiva. Para cada passo no tempo, o sistema de equações obtido para uma dada malha estruturada foi resolvido pelo método de Gauss-Seidel. O código computacional foi desenvolvido em FORTRAN, usando o estúdio CVF 6.6.0, na plataforma Windows Vista. A solução proposta foi validada usando soluções analíticas e numéricas da equação de difusão para várias geometrias, permitindo validar malhas ortogonais e não-ortogonais. A análise e comparação dos resultados mostraram que a solução proposta forneceu resultados coerentes para todos os casos investigados. O código computacional desenvolvido foi aplicado na simulação, a partir de dados experimentais da secagem de telhas cerâmicas para as seguintes condições experimentais: temperaturas de 55,6 °C, 69,7 °C, 82,7 °C e 98,6 °C e teor de umidade inicial variando de 0,2345 até 0,2405 (b.s.). A simulação tornou possível determinar o coeficiente de difusão efetivo em função da razão de umidade e da temperatura do ar de secagem e também o valor do coeficiente de transferência convectivo de massa correspondente para cada temperatura. / This work presents a three-dimensional numerical solution for the diffusion equation in transient state, in an arbitrary domain. The diffusion equation was discretized using the finite volume method with a fully implicit formulation and generalized coordinates, for the equilibrium and convective boundary condition. For each time step, the system of equations obtained for a given structured mesh was solved by the Gauss-Seidel method. A computational code in FORTRAN, using the CFV 6.6.0 Studio, in a Windows Vista platform was developed. The proposed solution was validated by analytical and numerical solutions of the diffusion equation for several geometries. The geometries tested enabled to validate both orthogonal and non-orthogonal meshes. The analysis and comparison of the results showed that the proposed solution provides correct results for all cases investigated. The developed computational code was applied in the simulation, using experimental data of the drying of ceramic roof tiles, for the following experimental conditions: temperature from 55.6; 69.7; 82.7; 72.8 and 98.7 °C, initial moisture content from 0.2345 up to 0.2405 (d.b.). The simulation makes it possible to determine an expression for the diffusion coefficient as a function of the moisture content and temperature of the drying air, and also the value of the convective mass transfer coefficient corresponding to each temperature.

Recently, 3D printing has been increasingly used to create physical models of the vocal tract with geometries obtained from magnetic resonance imaging. These printed models allow measuring the vocal tract transfer function, which is not reliably possible in vivo for the vocal tract of living humans. The transfer functions enable the detailed examination of the acoustic effects of specific articulatory strategies in speaking and singing, and the validation of acoustic plane-wave models for realistic vocal tract geometries in articulatory speech synthesis. To measure the acoustic transfer function of 3D-printed models, two techniques have been described: (1) excitation of the models with a broadband sound source at the glottis and measurement of the sound pressure radiated from the lips, and (2) excitation of the models with an external source in front of the lips and measurement of the sound pressure inside the models at the glottal end. The former method is more frequently used and more intuitive due to its similarity to speech production. However, the latter method avoids the intricate problem of constructing a suitable broadband glottal source and is therefore more effective. It has been shown to yield a transfer function similar, but not exactly equal to the volume velocity transfer function between the glottis and the lips, which is usually used to characterize vocal tract acoustics. Here, we revisit this method and show both, theoretically and experimentally, how it can be extended to yield the precise volume velocity transfer function of the vocal tract.

The performance evaluation and parametric studies of an Inertance Tube Pulse Tube Refrigerator (IPTR) are performed for different length-to-diameter ratios, with the Computational Fluid Dynamics (CFD) package FLUENT. The integrated model consists of individual models of the components, namely, the compressor, compressor cooler, regenerator, cold heat exchanger, pulse tube, warm heat exchanger, inertance tube and the reservoir. The formulation consists of the governing equations expressing the conservation of mass, momentum and energy with axi-symmetry assumption and relations for the variable thermophysical properties of the working medium and the regenerator matrix, and friction factor and heat transfer coefficients in oscillatory flows. The local thermal non-equilibrium of the gas and the matrix is taken into account for the modeling of heat exchangers and the regenerator which are treated as porous zones. In addition, the wall thickness of the components is also accounted for. Dynamic meshing is used to model the compressor zone. The heat interaction between pulse tube wall and the oscillating gas, leading to surface heat pumping, is quantified. The axial heat conduction is found to reduce the overall performance. The thermal non-equilibrium results in a higher cold heat exchanger temperature due to inefficiencies. The dynamic characteristics of pulse tube are analyzed by introducing a time constant. The study is extended to other types of PTRs, namely, the Orifice type Pulse Tube Refrigerator (OPTR), Double Inlet type Pulse Tube Refrigerator (DIPTR) and a PTR with parallel combination of inertance tube and orifice (OIPTR). The focus of the second phase of analysis is the pulse tube region. The oscillatory flow and temperature fields in an open-ended pipe driven by a time-wise sinusoidally varying pressure at one end and subjected to an ambient-to-cryogenic temperature difference across the ends, is numerically studied both with and without the inclusion of buoyancy effects. Conjugate effects arising out of the interaction of oscillatory flow with heat conduction in the pipe wall are taken into account by considering a finite thickness wall with an insulated exterior surface. Parametric studies are conducted with frequencies in the range 5-15 Hz for an end-to-end temperature difference of 200 K. As the pressure amplitude increases, the temperature difference between the wall and the fluid decreases due to mixing at the cold end. The pressure amplitude and the frequency have negligible effect on the time averaged Nusselt number. The effect of buoyancy is studied for hot side up and cold side up configurations. It is found that the time averaged Nusselt number does not change significantly with orientation or Rayleigh number. Sharp changes in Nusselt number and velocity profiles and an increase in energy transfer through solid and gas were observed when natural convection comes into play with hot end placed down. Cooldown experiments are conducted on a preliminary experimental setup. Comparison of the numerical and experimental cooldown curves disclosed a number of areas where improvement is required, primarily the leakage past the piston and the design of the heat exchangers. The setup is being improved to bring out a second and improved version for attaining the lower cold heat exchanger temperature.

L’un des principaux objectifs de la physique des réacteurs nucléaires est de caractériser la répartition aléatoire de la population de neutrons au sein d’un réacteur. Les fluctuations de cette population sont liées à la nature stochastique des interactions des neutrons avec les noyaux fissiles du milieu : diffusion, capture stérile, ou encore émission de plusieurs neutrons lors de la fission d’un noyau. L’ensemble de ces mécanismes physiques confère une structure aléatoire branchante à la trajectoire des neutrons, alors modélisée par des marches aléatoires. Avec environs 10⁸ neutrons par centimètre cube dans un réacteur de type REP à pleine puissance en conditions stationnaires, les grandeurs physiques du système (flux, taux de réaction, énergie déposée) sont, en première approximation, bien représentées par leurs valeurs moyennes respectives. Ces observables physiques moyennes obéissent alors à l’équation de transport linéaire de Boltzmann. Au cours de ma thèse, je me suis penchée sur deux aspects du transport qui ne sont pas décrits par cette équation, et pour lesquels je me suis appuyée sur des outils issus de la théorie des marches aléatoires. Tout d’abord, grâce au formalisme de Feynman-Kac, j’ai étudié les fluctuations statistiques de la population de neutrons, et plus particulièrement le phénomène de « clustering neutronique », qui a été mis en évidence numériquement pour de faibles densités de neutrons (typiquement un réacteur au démarrage). Je me suis ensuite intéressée à différentes propriétés de la statistique d’occupation des neutrons effectuant un transport anormal (càd non-exponentiel). Ce type de transport permet de modéliser le transport dans des matériaux fortement hétérogènes et désordonnés, tel que les réacteurs à lit de boulets. L’un des aspects novateurs de ce travail est la prise en compte de la présence de bords. En effet, bien que les systèmes réels soient de taille finie, la plupart des résultats théoriques pré-existants sur ces thématiques ont été obtenus sur des systèmes de taille infinie. / One of the key goals of nuclear reactor physics is to determine the distribution of the neutron population within a reactor core. This population indeed fluctuates due to the stochastic nature of the interactions of the neutrons with the nuclei of the surrounding medium: scattering, emission of neutrons from fission events and capture by nuclear absorption. Due to these physical mechanisms, the stochastic process performed by neutrons is a branching random walk. For most applications, the neutron population considered is very large, and all physical observables related to its behaviour, such as the heat production due to fissions, are well characterised by their average values. Generally, these mean quantities are governed by the classical neutron transport equation, called linear Boltzmann equation. During my PhD, using tools from branching random walks and anomalous diffusion, I have tackled two aspects of neutron transport that cannot be approached by the linear Boltzmann equation. First, thanks to the Feynman-Kac backward formalism, I have characterised the phenomenon of “neutron clustering” that has been highlighted for low-density configuration of neutrons and results from strong fluctuations in space and time of the neutron population. Then, I focused on several properties of anomalous (non-exponential) transport, that can model neutron transport in strongly heterogeneous and disordered media, such as pebble-bed reactors. One of the novel aspects of this work is that problems are treated in the presence of boundaries. Indeed, even though real systems are finite (confined geometries), most of previously existing results were obtained for infinite systems.

Recently, 3D printing has been increasingly used to create physical models of the vocal tract with geometries obtained from magnetic resonance imaging. These printed models allow measuring the vocal tract transfer function, which is not reliably possible in vivo for the vocal tract of living humans. The transfer functions enable the detailed examination of the acoustic effects of specific articulatory strategies in speaking and singing, and the validation of acoustic plane-wave models for realistic vocal tract geometries in articulatory speech synthesis. To measure the acoustic transfer function of 3D-printed models, two techniques have been described: (1) excitation of the models with a broadband sound source at the glottis and measurement of the sound pressure radiated from the lips, and (2) excitation of the models with an external source in front of the lips and measurement of the sound pressure inside the models at the glottal end. The former method is more frequently used and more intuitive due to its similarity to speech production. However, the latter method avoids the intricate problem of constructing a suitable broadband glottal source and is therefore more effective. It has been shown to yield a transfer function similar, but not exactly equal to the volume velocity transfer function between the glottis and the lips, which is usually used to characterize vocal tract acoustics. Here, we revisit this method and show both, theoretically and experimentally, how it can be extended to yield the precise volume velocity transfer function of the vocal tract.

Avec 80 millions de personnes déracinées à travers le monde, les espaces de refuge sont en train d’émerger comme les transformations urbaines les plus visibles des temps modernes. Ces espaces, dont la fonction première est d’abriter temporairement, servent souvent d’habitat pour les réfugiés pendant des décennies. Cependant, les États hôtes, majoritairement des pays en développement, persistent à accueillir les réfugiés selon des politiques à court-terme. Cet écart génère plusieurs tensions mais se manifeste explicitement dans la conception temporaire des espaces de refuge. Sur le plan théorique, alors que les migrations sont largement documentées, des connaissances limitées existent sur la reproduction de chez-soi. Les théories qui portent sur les espaces de refuge se concentrent surtout sur des enjeux géopolitiques et anthropologiques, négligeant l’espace en soi. Pauvres en nuances, elles classent ces espaces selon des conceptualisations dichotomiques souvent déconnectées du vécu des réfugiés. Cette recherche propose une nouvelle lecture des espaces de refuge à travers les lentilles du pouvoir, de la culture et de l’espace. Elle étudie l’appropriation de ces espaces en se basant sur l’exploration des pratiques sociales, économiques et politiques des réfugiés, de leurs interventions sur l’espace et du lien qu’ils développent avec leurs nouveaux environnements de vie. Elle révèle également l’influence des approches adoptées par la communauté internationale, les gouvernements d’accueil, les organismes humanitaires et les communautés hôtes. L’étude est qualitative exploratoire et adopte la méthode de l’étude de cas multiples. Cette approche permet d’acquérir une compréhension approfondie des perceptions des réfugiés des contextes sociopolitiques et économiques qui caractérisent leur vécu d’une part et de leurs représentations de l’espace d’autre part. Trois typologies d’habitat — deux habitations urbaines, deux campements informels et deux camps organisés — sont étudiées afin d’évaluer l’importance du type de l’espace par rapport à son appropriation. L’étude adopte l’ethnographie comme approche méthodologique complémentaire, dévoilant l’évolution des conditions de vie des réfugiés et la transformation de leurs espaces. Le cas à l’étude est celui des réfugiés syriens au Liban. Submergé par le nombre de réfugiés sur son territoire, le plus grand par nombre d’habitants au monde, le Liban exclut les réfugiés syriens des systèmes institutionnels, économiques et urbains dans le but de réduire leur accès au territoire, de limiter la durée de leur séjour et de prévenir la consolidation matérielle et immatérielle de leurs espaces. Toutefois, huit ans après, les stratégies adoptées par le gouvernement libanais se sont avérées infructueuses : le nombre des réfugiés syriens accueillis est sensiblement le même et leurs espaces se sont pour la plupart ghettoïsés. La thèse propose cinq résultats principaux : 1) l’enjeux central dans l’appropriation des espaces de refuge est un ensemble de géométries de pouvoirs politique, économique et social ; 2) la gouvernance faible de l’État d’accueil fragmente les systèmes traditionnels et permet l’émergence de structures de pouvoir informelles qui contrôlent les réfugiés et leurs espaces ; 3) l’exclusion des réfugiés exacerbe leur vulnérabilité et l’organise au profit de parties prenantes locales influentes. Elle réduit leurs chances d’émigrer et mène souvent à la ghettoïsation de leurs espaces ; 4) la typologie des espaces n’est pas centrale par rapport à leur appropriation ; 5) l’enracinement de l’identité dans le lieu d’origine est une idée basée sur des considérations politiques anti-migratoires. Les espaces de refuges évoluent, selon les opportunités et les défis dans le milieu d’accueil, suivant un continuum entre non-lieux temporaires et lieux de vie socioculturels. En transcendant leur marginalisation et leur homogénéisation, cette recherche dévoile la réalité intime des espaces de refuge. Elle montre que souvent, ils deviennent des chez-soi, lieux de vie quotidiens qui abritent des individus qui forment des groupes sociaux culturellement distincts et économiquement hiérarchisés. D’un point de vue théorique, elle montre que l’accueil des réfugiés est souvent basé sur l’hostipitalité, une hospitalité hostile qui vulnérabilise les réfugiés et facilite leur exploitation. Elle révèle que l’appropriation des espaces de refuge augmente proportionnellement avec l’inclusion institutionnelle et l’autonomisation socioéconomique des réfugiés, concourant à la reproductibilité rhizomique de leur identité individuelle et collective. D'un point de vue pratique, cette recherche démontre que, sous prétexte de raccourcir la durée de l’accueil des réfugiés, les politiques d’accueil sont en réalité adoptées dans l’intérêt économique et politique d’acteurs étatiques et privés. Dans le but d’atteindre une meilleure justice spatiale, elle recommande aux gouvernements d’accueil un changement de paradigme à travers l’adoption de stratégies plus inclusives à l’égard des réfugiés menant à leur autogestion et leur développement et d’approches adaptées à l’usage et à la durée de leurs espaces. / With 80 million people uprooted around the world, refuge spaces are coming to be the most visible urban transformations of modern times. These spaces, whose primary function is to shelter, often accommodate refugees for decades. Yet, host states, mostly developing countries, continue to host refugees without adopting comprehensive, long-term strategies for their integration, causing acute political, socio-economic, and humanitarian problems. The lack of a long-term solution is explicitly revealed by the conceptions of refugee spaces, often designed as temporary solutions. From a theoretical perspective, while social scientists and geographers have widely documented the geopolitical and anthropological aspects of forced migrations, they have neglected the concept of space appropriation and the production of place identity in refugee spaces. Indeed, their classification of space/place is often based on dichotomous conceptualizations and differs from refugees’ real-life experience. This research examines refugee spaces through the lenses of power, culture, and space. It provides new evidence on the appropriation of these spaces through refugees’ social, economic, and political practices, their interventions on space, and their perceptions of their new living environment. It also examines the impact of the strategies adopted by the international community, host governments, humanitarian organizations, and local communities. The research method is qualitative and exploratory; it is based on a multiple case study design. This methodological approach provides an in-depth understanding of refugees' perceptions on the socio-political environment undergirding displacement and on their representations of space. Three space typologies — urban dwellings, informal settlements, and organized camps — are studied with the purpose of assessing the relevance of the space-type in relation to its appropriation. The study uses ethnography as a complementary methodological approach, shedding light on the evolution of refugees’ living conditions over time and the transformation of their spaces from a cultural standpoint. It specifically focuses on Syrian refugees in Lebanon, a country which hosts the largest number of refugees per capita in the world. Overwhelmed by the number of refugees hosted, Lebanon excludes Syrian refugees from formal legal, economic, and urban systems, limiting their access to the territory, reducing the duration of their stay, and preventing the tangible and intangible consolidation of their living spaces. Yet, eight years later, the strategies adopted by the Lebanese government have proven unsuccessful: the number of Syrian refugees is roughly the same as at the beginning of the conflict and most of their spaces have been ghettoized. Results show that: 1) complex geometries of political, economic, and social powers determine the appropriation of refugee spaces; 2) weak state authority fragments traditional governance systems which leads to the emergence of informal power structures that control refugees and their spaces; 3) refugees’ exclusion exacerbates their vulnerability, while benefitting local stakeholders, subsequently reducing their chances of emigration and leading to the ghettoization of their living spaces; 4) the typology of spaces is not a major variable in relation to their appropriation; 5) the rooting of identity in the place of origin is an idea based on anti-migration political viewpoints; refugee spaces can evolve along a continuum between temporary non-places and socio-cultural places of life depending on the opportunities and challenges in the host context. Transcending the stigmatization, marginalization, and homogenization of refugee spaces, this research reveals the intimate reality of these spaces. It shows that they often become places of everyday life for refugees who form culturally dissimilar and economically hierarchical social groups. From a theoretical point of view, this research shows that hosting policies are often based on hostipitality, or a hostile form of hospitality which exacerbate refugees’ vulnerability and facilitates their exploitation. It shows that refugees’ appropriation and control of their living spaces increase proportionally with their legal inclusion and their socio-economic empowerment by the host state, inciting the rhizomic reproducibility of their individual and collective identity in their new habitat. From a practical point of view, the research shows that hosting policies adopted on the pretext of shortening the duration of refugees’ settlement are in fact in the interest of state and private actors. With the purpose of achieving spatial justice, the study recommends a change of paradigm in refugee policies with approaches that are more inclusive towards refugees leading to their self-management and their development, and adapted to the use and duration of their living spaces.

Šimon Knoška The spherically symmetric spacetimes represent one of the most important classes of solutions in general relativity. Therefore, it is very natural to study them also in the context of modified theories of gravity. We directly continue in the previous works in quadratic gravity, where the generalised solutions with the constant Ricci scalar were found in the form of power series expansion in the conformal coordinates. In this work, we have found an alternative expression of this solution in the Robinson-Trautman-like coordinates analogously in the form of power series expansion around the horizon. Al- though the prescribed recurrent power series solution is more complicated than that in the conformal-to-Kundt coordinates, it posses numerous advantages. Namely, the trans- formation to the Schwarzschild-like coordinates is considerable simple and the physical interpretation of the coordinates is more evident. These properties are demonstrated in the preliminary investigation of the geodesic motion of the test particles near the black hole with analysis of the effect of the so-called Bach parameter. In particular, we have observed that the Bach parameter together with the positive cosmological constant Λ > 0 has a significant impact on the global structure of the spacetime.

Within this work we have been interested in the frame approach to analysis of the field equations in the context of theories of gravity, in particular, the Einstein General Relativ- ity and Quadratic theory of gravity. As the starting point we have summarised the least action principle formulation of the General Relativity and introduced the Quadratic grav- ity extending the classic Einstein-Hilbert action by adding quadratic curvature terms. The Quadratic gravity field equation have been rewritten into the form separating the Ricci tensor contribution. As a next step we have reviewed the Newman-Penrose formal- ism on a purely geometrical level and discussed employing the field equations constraints. While in the case of General Relativity it is quite trivial, in the Quadratic gravity it be- comes much more involved, however, the General Relativity procedure can be followed even here. As an illustration, we have formulated the constraints on the gravitational field in the cases of the spherically symmetric spacetimes and so-called pp-waves both in the GR as well as Quadratic gravity. 1

Das Institut für Tragwerksentwurf (ITE) und das Institut für Baustof e, Massivbau und Brandschutz (iBMB) der TU Braunschweig bearbeiteten in der ersten Förderperiode des SPP 1542 „Leicht Bauen mit Beton“ gemeinsam das Teilprojekt „Entwicklung neuartiger Verbindungen für geometrisch komplexe Flächen- und Stabwerkselemente aus UHPC“. Schwerpunkt waren umfangreiche Untersuchungen zu geometrisch komplexen und hochpräzise hergestellte trocken gefügten Stoßverbindungen für dünnwandige UHPC-Bauteile zur Übertragung von Druck-, Biege- und Scherkräften. Zur Verbesserung der Zugtragfähigkeit und des Nachbruchverhaltens wurde im Forschungsprojekt stahlfaserverstärkter ultrahochfester Beton (UHPFRC) verwendet. Die einzelnen Arbeitspakete waren entsprechend der Expertisen der beiden Institute aufgeteilt. Während sich das ITE insbesondere mit der Entwicklung der Bauteil- und Fugengeometrien sowie dem Schalungsbaus befasste, lagen Planung und Umsetzung der experimentellen und numerischen Material- und Bauteiluntersuchungen in der Verantwortung des iBMB. [Aus. Einleitung) / The Institute of Structural Design (ITE) and the Institute of Building Materials, Concrete Structures and Fire Safety (iBMB) of the Technical University of Braunschweig worked together in the f rst funding period of the SPP 1542 “Concrete Light” on the subproject “Development of novel jointing systems for complex beam surface and spatial elements made of UHPFRC”. The focus was on extensive investigations of geometrically complex and high-precision dry-jointed connections for thin-walled UHPC components for the transmission of compressive, bending and shear forces. Steel f bre reinforced ultra-high performance concrete (UHPFRC) was used in the research project to improve the tensile strength and post fracture behaviour. The individual work packages were divided according to the expertise of the two institutes. While the ITE was particularly concerned with the development of the component and joint geometries as well as the formwork construction, the iBMB was responsible for the planning and implementation of the experimental and numerical material and element analyses. [Off: Introduction]

Die Mitwirkung bei dem Sonderforschungsbereich 1333 (SFB 1333) eröffnete die exklusive Gelegenheit, eingehende Kenntnisse über Theorie und Praxis der Röntgenabsorptions-spektroskopie (XAS) zu erwerben. Diese Expertise fand im Rahmen eigenständig geleiteter Kooperationsprojekte auf dem Gebiet der Rh- und Ru-Koordinationschemie vielseitige Anwendung: Neben der Untersuchung Lösungsmittel-bedingter Ligandensubstitutionen zählten auch mechanistische Studien homogen-katalysierter Transformationen sowie die spektroskopische Evaluierung verschiedener Immobilisierungsstrategien zu dem Anwendungs-Portfolio der XAS-Analyse. Für die Forschungsgruppe Plietker erwies sich XAS als ein geeignetes Instrument, um die Entwicklung des Konzepts der molekularen heterogenen Katalyse in definierten, dirigierenden Geometrien zu unterstützen. Das flexible Anwendungsspektrum dieser Spektroskopie-Methode gestattete, das positive Resultat der Immobilisierung eines Ru-basierten H2-Autotransfer¬katalysators auf spektroskopischem Niveau zu verifizieren. Eingehende XANES- und EXAFS-Analysen untermauerten dabei, dass dessen Fixierung innerhalb des Porensystems eines SBA-15-Materials lediglich mit einer marginalen strukturellen oder elektronischen Beeinflussung des Ru-Zentralatoms einherging. Außerdem ließen sich die chemischen Auswirkungen einer variierenden Distanz zwischen immobilisiertem Ru-Komplex und Porenwand auf das Zentralatom analysieren sowie die katalytisch aktive Spezies des recyclierten Ru-Komplexes mit hoher Wahrscheinlichkeit identifizieren. In der parallelen Untersuchung einer bis dato nur oberflächlich erforschten Kategorie kationischer Fe-Diazo-Komplexe erwies sich XAS zudem als Schlüsselmethode für die Veranschaulichung des Elektronendichte-abhängigen Equilibriums zwischen trigonal-bipyramidalem und oktaedrischem Bindungsisomer. Ferner wurden bei dieser Untersuchung deutliche Hinweise auf die Empfindlichkeit dieser Gleichgewichtslage gegenüber einer fortwährenden Exposition mit harter Röntgenstrahlung sowie der CLICK-Chemie-basierten Immobilisierung in mesoporösem Trägermaterial offensichtlich. Neben der Analyse homogener und immobilisierter Übergangsmetall-Komplexe wurde das Spektrum der in der Forschungsgruppe Plietker bisher einzig in Mikrowellen-Reaktoren praktizierten C H-Aminierungen um die bei Raumtemperatur stattfindende, TBA[Fe]-katalysierte Sultambildung erweitert. Deren Anwendungsbreite ließ sich durch die Erarbeitung eines synthetischen Zugangs zu verschiedenen o-monofunktionalisierten, aber auch asymmetrisch 2,6-difunktioanlisierten Arylsulfonylaziden, über das bisher in der Literatur bekannte Maß ausdehnen. Neben präparativen Untersuchungen, als Teil der für diese Insertionsreaktion durchgeführten Mechanismusstudie, erfolgten im Rahmen eines Forschungsaufenthaltes an der University of Rochester erste Mössbauer-Analysen des postulierten TBA[Fe]-Nitren-Intermediats. Darüber hinaus erwies sich der bereits in der homogenen H2-Autotransferkatalyse etablierte Ru(NNNN)-Komplex ebenfalls als ein wirkungsvoller Katalysator für die intramolekulare C H Aminierung aromatischer Sulfonylazide. Der Einsatz seines immobilisierten Analogons erlaubte schlussendlich die Kombination der Fachgruppen-intern bisher ausnahmslos homogen-katalysierten C-H-Aminierung mit dem neuartigen Konzept der molekularen heterogenen Reaktionsführung in definierten, dirigierenden Geometrien. / Participating in the Collaborative Research Center 1333 (CRC 1333) offered the exclusive opportunity to accumulate detailed knowledge in theory and application of X-ray Absorption Spectroscopy (XAS). This expertise was afterwards used in independently managed cooperation projects focusing on solvent-based ligand substitutions, mechanistic studies of homogeneously catalyzed transformations as well as the spectroscopic evaluation of different immobilization strategies. Within the Plietker research group, XAS became an adequate tool to support the development of the concept of molecular heterogeneous catalysis in confined geometries. XAS was applied to verify the successful immobilization of the Ru(NNNN)-based H2-autotransfer catalyst spectroscopically. XANES- and EXAFS analysis thereby proved the attachment of this complex in SBA-15 support with only small electronic and steric influence on the Ru-center. Furthermore, XAS provided valuable information about possible structural consequences for the ligand sphere caused by different distances between immobilized complex and pore wall as well as probably disclosed the catalytic active species that is immobilized in recycled solid support. In a parallel exploration of a so far only rudimentarily investigated category of cationic Fe-diazo complexes, XAS turned out to be the key method for visualizing the electron density dependent equilibrium between their trigonal-bipyramidal and octahedral coordination mode. In addition, this study also gathered information about the sensitivity of the underlying isomerization reaction to continuous exposition to hard X-rays as well as to the CLICK-chemistry based immobilization in mesoporous material. Beyond the analysis of these homogeneous and immobilized transition metal-complexes, the portfolio of the in the Plietker group so far only microwave-based C-H-amination reactions was expanded by a room temperature TBA[Fe]-catalyzed sultame formation. In order to increase its substrate scope, a new synthetic strategy for asymmetric 2,6-disubstituted arenesulfonyl azides was created guaranteeing the introduction of various carbon-based substituents. Next to preparative experiments as part of mechanistical studies for this insertion reaction, MÖSSBAUER analysis of the postulated TBA[Fe]-nitrene intermediate was performed during a research stay at the University of Rochester. Additionally, the homogeneous Ru(NNNN)-complex applied in H2-autotransfer reactions proved to efficiently catalyze the intramolecular C-H-amination of aromatic sulfonyl azides as well. The usage of its immobilized analogue finally culminated in the fusion of the group-intern only homogeneously catalyzed C-H-amination reactions with the novel concept of molecular heterogeneous catalysis in confined geometries.