Esta pesquisa trata de uma análise do trabalho de dez eletricistas que atuam em espaços confinados de redes subterrâneas de distribuição de energia, na Companhia Estadual de Energia Elétrica, Porto Alegre, RS. Foi identificada a demanda ergonômica dos eletricistas, com base em um método participativo (Análise Macroergonômica do Trabalho) de levantamento e avaliação dos dados, que gerou insumos para a melhoria das condições de trabalho e segurança e, conseqüente, promoção de prevenção de acidentes. A pesquisa revelou que os eletricistas consideram como aspectos mais positivos do trabalho os relacionamentos entre chefia, supervisores e colegas. Em contrapartida, apontam problemas críticos de diversas naturezas: biomecânico/posto, organização do trabalho, ambiental e relacionados à empresa. Também foram identificados níveis elevados de demandas físicas e mentais do trabalho, concluindo-se que o medo, evidenciado no discurso dos eletricistas, é referente ao trabalho com eletricidade e não ao trabalho em espaços confinados. Além disso, a pesquisa apontou cinco procedimentos, considerados como padrões mínimos, para a realização de trabalhos seguros em espaços confinados: reconhecimento, monitoramento da atmosfera, ventilação, treinamento e resgate.Apesar dos eletricistas não terem ciência da existência destes procedimentos, os mesmos foram citados, direta ou indiretamente nas entrevistas, como aspectos relevantes ao trabalho, sendo atribuído a maioria deles um baixo nível de satisfação. Com isso, conclui-se que a implantação de um programa de permissão de entrada em espaços confinados, além de promover a segurança neste ambientes tem relação direta com a satisfação dos trabalhadores. / The focus of this dissertation is the work analysis of ten electricians who act in confined space at underground power lines at the Estate Electricity Company in Porto Alegre, RS. It was identified the electricians’ ergonomic demand items. The research was carried out according to the participatory methods of survey and assessment of data, to improvement of safety and work conditions and, therefore, to prevent accidents. The research disclosed that the electricians have the relationship with their superiors, supervisors, and workmates as the most positive aspect of the job. On the other hand, they point out critical problems from different causes: biomechanical, task organization, environmental, and the ones related to the company. Overload regarding physical and mental work demand has been identified, proving that the fear, evident in the professionals’ speech is about the electricity, and not related to confined underground spaces. Besides, the research also displayed five procedures regarded as minimal standards to execute safe work in confined spaces: recognition, testing and monitoring atmosphere, ventilation, training and rescue. Despite the little knowledge electricians have on this criteria, some points of it were reported, some in an indirect way, during the interviews as relevant aspects to the work, being attributed to most of them a low level of satisfaction. Therefore, it comes to the conclusion that the implantation of a Permit-Requires Space Program, besides promoting accidents prevention in these spaces, has a direct relationship with the workers’ satisfaction.

Les matériaux poreux basés sur les polymères font l’objet de recherches nombreuses et variées depuis leur découvertes et jusqu’à aujourd’hui encore. Leurs propriétés uniques et remarquables, comme par exemple une fonctionnalisation aisée ou une large gamme de porosité accessibles, couplées à leur faible coût de production les rendent attrayant pour de nombreuses applications. Parmi elles, la catalyse supportée est en plein essor, spécialement depuis l’avènement des nanoparticules. Durant ce travail de thèse, nous avons développé différents matériaux polymères pouvant servir de support, se focalisant majoritairement sur trois types de matériaux : des matériaux polymères massiques, des matrices polymères poreuses en capillaire ainsi que des polystyrènes poreux provenant de la dégradation sélective de copolymères diblocs.Dans un premier temps, différentes stratégies ont été employées pour l’immobilisation et la génération de nanoparticules sur les matériaux massiques. L’un a consisté en la synthèse d’un monomère contenant un pont disulfure qui, après réduction, a permis la libération de groupement thiol permettant l’accrochage de nanoparticules d’or. La seconde a consisté à réduire de manière originale les nanoparticules en utilisant un gaz, l’hydrogène. Dans un seconde partie, la synthèse de différentes matrices polymères dans des capillaires a été réalisée. Tout d’abord, une matrice déjà connue de la littérature à base de N-acryloxysuccinimide a été utilisée, après modification via thiol-ène et substitution nucléophile par différentes amines, pour immobiliser des nanoparticules de cuivre ainsi que d’or, respectivement. D’autre part, une nouvelle matrice à partir de carbonate cyclique aura, elle, été utilisée après modification, pour l’immobilisation de nanoparticules de platine. Enfin à partir de copolymères diblocs possédant différentes jonctions entre chaque bloc (un pont disulfure ainsi qu’un acétal), différents polystyrènes poreux ont été obtenus. Les copolymères possédant une jonction acétal à lui été utilisé pour l’immobilisation de nanoparticules d’or, permettant la mise en place des réactions de réduction de nitro, d’homocouplage boronique ainsi que de la mise en cascade de ces deux réactions / Porous materials based on polymers have been the subject of intense and various researches since their discovery until now. Their unique and remarkable properties, like their easy functionalization or their large porosity range reachable for instance, coupled with their low production cost makes them attractive for numerous applications. Among them, supported catalysis is booming, especially since the rising of nanoparticles. During this Ph.D. contribution, we have developed different polymeric materials, which could be used as support, focusing mainly onto three types: bulky materials, porous polymeric matrixes into capillaries and porous polystyrene arising from the selective degradation of diblocks copolymers.Firstly, different strategies have been employed for the immobilization and the generation of nanoparticles onto bulk materials. On the one hand, the synthesis of a monomer, bearing a disulphide bridge which can, after a reduction step, free a thiol moiety allowing us to anchor gold nanoparticles. On the other hand, a new route to reduce nanoparticle has been employed using gaseous hydrogen. In another part, the syntheses of different polymeric matrixes into capillaries have been made. First, we used an already known matrix, based on N-acryloxysuccinimide -after modification step via thiol-ene reaction and nucleophilic substitution by amines- to anchor copper or gold nanoparticles, respectively. Also, a new matrix based on cyclic carbonates has been used, after modification, to immobilized platinum nanoparticles. Finally, starting from diblocks copolymers possessing different junctions between both blocks (disulphide bridge or acetal), porous polystyrenes have been obtained. The copolymers bearing an acetal have been implemented to immobilized gold nanoparticles, catalysing several reactions like nitro reduction, boronic homocoupling as well as the cascade reaction of both

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Brazilian agricultural sector constitutes itself as an important resource income for small producers all of whose manpower has been family character. The reduction of costs of the production process continues to make feasible the determining factor activity. For this it becomes necessary to verify the operational costs of production and analyze the factor which most impacts the costs of an enterprise of this nature. From this, it is necessary to think of a solution of working so as to integrate the production of energy and food. The objective of this study is to evaluate the economic viability of milk production in dairy cattle management systems pasture and confined in different scenarios related to animal feed, among which can highlight the determination of the integrated system of deployment of profitability of ethanol production and silage using sweet sorghum as raw material. In this study a quantitative approach was used. Realized the diagnosis of the dairy sector from the northwest region of the Rio Grande do Sul state (RS) through the withdrawals from analyzes performed by official bodies of the region (EMATER). The costs involved in the production of milk were provided obtained from the informal interviews in an intensive property that employs confined system and another system which uses intensive pasture. After assessing the costs held the integrated assessment of combustible ethanol production and silage for animal feed in a confined system. Diagnostic results of the show are positive and prospectus for growth. In relation to the production costs intensive pasture system presented a cost of R$ 0.72 per liter of milk produced, and the Intensive confined system has a cost of R$ 0.55 cents per liter. The economic analysis the two production systems are viable in the long run. About the integrated system, it is concluded it is a viable system and can increase the income of the small farmers. When analyzing the integrated production of ethanol and silage sweet sorghum and using the product in food, the profitability amounts to R$ 3.500,75 per hectare by employing confined system. / O setor agropecuário brasileiro constitui-se como importante fonte de renda para pequenos produtores cuja mão de obra é de cunho familiar. A redução dos custos do processo de produção continua sendo fator determinante para viabilizar a atividade. Para isso, faz-se necessário verificar os custos operacionais de produção e analisar o fator que mais impacta nos custos, de um empreendimento dessa natureza. A partir disso, é preciso pensar em uma solução de trabalhar de forma a integrar a produção de energia e alimento. Assim, o objetivo deste trabalho é avaliar a viabilidade econômica da produção de leite em sistemas de manejo do gado leiteiro pastoril e confinado, em diferentes cenários relacionados à alimentação animal, dentre os quais, se pode destacar a determinação da receita líquida de implantação de sistema integrado de produção de etanol e silagem, empregando sorgo sacarino como matéria-prima. Neste estudo foi utilizada uma abordagem quantitativa. Realizou-se o diagnóstico do setor leiteiro da região noroeste do Rio Grande do Sul (RS) através da análise de levantamentos realizados por órgãos oficiais da região (EMATER). Os custos envolvidos na produção de leite foram obtidos a partir de entrevista informal. Avaliou-se duas propriedades, uma que emprega o sistema intensivo em confinamento e outra que utiliza o sistema intensivo a pasto. Após a avaliação dos custos realizou-se a avaliação integrada de produção de etanol combustível e silagem para a alimentação animal em sistema confinado. Os resultados do diagnóstico apresentaram-se positivos e prospectos ao crescimento. Com relação aos custos de produção, o sistema intensivo a pasto apresentou custo de R$ 0,72 por litro de leite produzido, e o sistema Intensivo em confinamento R$ 0,55 centavos por litro. A análise econômica demonstra que os dois sistemas de produção são viáveis em longo prazo. Quanto ao sistema integrado, conclui-se que é um sistema viável e pode aumentar a renda do pequeno produtor rural. Ao analisar a produção integrada de etanol e ensilagem de sorgo sacarino e a utilização do mesmo na alimentação, a receita líquida chega a R$ 3.500,75 por hectare.

Doctor of Philosophy / Department of Civil Engineering / Asadollah Esmaeily / Over the past 30 years, FRP composites (carbon, glass, or aramid fibers) have arisen as a method of retrofitting existing reinforced concrete structures to bring them up to current code standards of confinement and ductility. The development of stress-strain models for FRP confined concrete began with the adaptation of steel confinement models then progressed to models specifically developed based on test results from FRP confined specimens. State of the art stress-strain models for FRP confined concrete models may now be validated against a wide variety of published experimental results. Recent publications show researchers branching out and looking at other aspects of FRP confined concrete behavior, including the impact of sustained service loads on long term and ultimate behavior. An experimental program which examines the effects of sustained service loading on the ultimate axial performance of FRP confined concrete is presented. The program's purpose is to determine whether or not a material model developed without the presence of a sustained load accurately predicts the ultimate stress-strain response of FRP confined concrete previously subjected to a sustained service load. Equipment and procedures were developed to model the critical events in a building life cycle: construction, sustained service loading, minor critical events, rehabilitation, and ultimate performance. Varying the order of these events produces a simulated life cycle allowing analysis of the impact of strain history on ultimate performance. The results of the experimental program indicate that the presence of a sustained service load changes the expected failure mode from FRP rupture to FRP de-lamination and the stress-strain response of a specimen is approximately 10% below published models when sustained service loads are included in the life cycle. A comprehensive modeling process is proposed for modeling significant events in a structure's life cycle. Impacts on earthquake engineering and reliability studies are addressed and future research suggested. This research shows that life cycle modeling can improve the design and rehabilitation of structures so that they meet safety requirements in future seismic events.

Philosophiae Doctor - PhD / This thesis deals with some fundamental aspects of groundwater models. Deterministic mathematical models of groundwater are usually used to simulate flow and transport processes in aquifer systems by means of partial differential equations. Analytical solutions for the deterministic mathematical models of the Theis problem and the transient confined-unconfined flow in a confined aquifer are investigated in the thesis. The Theis equation is a most commonly applied solution for the deterministic mathematical model of the Theis problem. In the thesis, a most simplified similarity transformation method for derivation of the Theis equation is proposed by using the Boltzmann transform. To investigate the transient confined-unconfined flow towards a fully penetrating well in a confined aquifer, a new analytical solution for the deterministic mathematical models of interest is proposed in the thesis. The proposed analytical solution considers a change of hydraulic properties (transmissivity and storativity) during the confined-unconfined conversion. Based on the proposed analytical solution, a practical method to determine distance of the conversion interface from pumping well and diffusivity of the unconfined region is developed by using a constant rate test. Applicability of the proposed analytical solution is demonstrated by a comparison with previous solutions, namely the MP and the Chen models. The results show that the proposed analytical solution can be used to assess the effect of the change of diffusivity on the transient confined-unconfined flow. The MP model is only accepted if the transmissivity during the confined-unconfined conversion is constant. The Chen model, given as a special case of the proposed analytical solution, is limited to the analysis of the transient confined-unconfined flow with a fixed diffusivity. An important application of groundwater models is to estimate parameters, such as hydraulic properties and flow dynamics, of groundwater systems by assessing and analysing field data. For instance, the pumping and the hydrochemistry and environmental tracer tests are two effective ways to obtain such data. To evaluate hydraulic properties of aquifer systems by derivative interpretation of drawdown data from pumping tests, a new diagnostic analysis method is proposed based on a lg-lg drawdown derivative, dlgs/dlgt, and the differentiation algorithm namely Lagrange Interpolation Regression (LIR) in the thesis. Use of a combined plot of dlgs/dlgt and a semi-lg drawdown derivative (ds/dlgt) is made to identify various flow segments during variable discharge tests with infinite conditions, constant rate tests in bounded aquifers and tests involving double-porosity behaviours. These can be applied to further characterize pumped aquifers. Compared to traditional diagnostic analysis method using plot of ds/dlgt alone, the combined drawdown derivative plot possesses certain advantages identified as: (1) the plot of dlgs/dlgt is strikingly sensitive for use in unveiling differences between pumping and its following recovery periods in intermittent variable discharge tests; (2) storativity (S) of pumped aquifers can be evaluated by using the combined plot; and (3) quantitative assessments of double-porosity behaviours can also be achieved. Based on two case studies, advantages and disadvantages of uses of the LIR and other existing differentiation methods in calculations of numerical drawdown derivative are demonstrated in practice. The results suggest that the LIR is a preferred method for numerical differentiation of drawdown data as it can be used to effectively minimise noisy effects. The proposed derivative approach provides hydrologists with an additional tool for characterizing pumped aquifers. Use of hydrochemistry and environmental tracer tests to assess flow dynamics of groundwater systems is demonstrated via a case study in the dolomite aquifer of South Africa. An emphasis is on determining mean residence times (MRTs) of the dolomite aquifer by means of an appropriate box model with time series of 14C values of dissolved inorganic carbon (14C-DIC) and initial 14C activities of spring samples during 1970s and 2010s. To obtain the calibrated 14C MRTs, 13C values of dissolved inorganic carbon (δ13C-DIC) of the spring samples are applied to estimate mineral dissolution in the dolomite aquifer and calculate the initial 14C activities. The results indicate that the spring samples have about 50%-80% initial 14C activities. By using the appropriate box model, the calibrated 14C MRTs of the spring system are given within a range from ≤ 10 to 50 years. Additionally, the flow dynamics, including the recharge source and area, the effect of climate change on the temporal trend of the groundwater MRTs and the groundwater flow circulation, of the dolomitic spring system are also discussed for further possible management interventions in the dolomite aquifer.

Dans ce travail de thèse, une méthode de pénalisation en volume pour la simulation d'écoulements magnétohydrodynamiques (MHD) en domaines confinés est présentée. Les équations incompressibles de la MHD résistives sont résolues par le truchement d'un solveur pseudo-spectral parallèlisé. La pénalisation en volume est une méthode de frontières immergées, caractérisée par une grande flexibilité dans le choix de la géométrie de l'écoulement. Dans le cas présent, elle permet d'utiliser des conditions aux limites non-périodiques dans un schéma pseudo-spectral Fourier. La méthode numérique est validée et sa convergence est quantifiée pour des écoulements hydrodynamiques et MHD, en deux et trois dimensions, en comparant les résultats numériques à ceux de la littérature et à des solutions analytiques. Dans un second temps, la génération spontanée de moment cinétique et magnétique est étudiée pour des écoulements MHD confinés 2D et 3D. L'influence du nombre de Reynolds et du rapport des énergies cinétique/magnétique est explorée, ainsi que les différences induites par les conditions aux limites. Le fait que l'axisymétrie des frontières résulte en un terme de pression non-nul est primordial pour engendrer de grandes valeurs du moment cinétique. L'exclusivité de cette auto-organisation aux écoulements 2D est étudiée en considérant la MHD 3D en présence d'un fort champ magnétique axial. La suite est consacrée à la simulation d'un fluide conducteur dans un cylindre avec un forçage magnétique axial et poloidal. En faisant varier l'amplitude du forçage poloidal, différents états dynamiques sont atteints. Enfin, l'effet du nombre de Prandtl sur le seuil des instabilitées est étudié. / A volume penalization method for the simulation of magnetohydrodynamic (MHD) flows in confined domains is presented. Incompressible resistive MHD equations are solved in 3D by means of a parallelized pseudo-spectral solver. The volume penalization technique is an immersed boundary method, characterized by a high flexibility in the choice of the geometry of the considered flow. In the present case, it allows the use of conditions different from periodic boundaries in a Fourier pseudo-spectral scheme. The numerical method is validated and its convergence is assessed for two- and three-dimensional hydrodynamical and MHD flows by comparing the numerical results with those of the literature or analytical solutions. Then, the spontaneous generation of kinetic and magnetic angular momentum is studied for confined 2D and 3D MHD flows. The influence of the Reynolds number and of the ratio of kinetic/magnetic energies is explored, as well as the differences induced by the boundary conditions. The fact that axisymmetric borders introduce a non-zero pressure term in the evolution equation of the angular momentum is essential to generate large values of the angular momentum. It is investigated whether this self-organization is exclusively observed in 2D flows by considering 3D MHD in the presence of a strong axial magnetic field. The last part is devoted to the simulation of a conducting fluid in a periodic cylinder with imposed axial and poloidal magnetic forcing, implying a resulting magnetic field. By varying the amplitude of the poloidal forcing, different dynamical states can be achieved. The effect of the Prandtl number on the threshold of the instabilities is then studied.

The aim of the project is to explore 3D localisation of a sensor “pill”, contained in an enclosed vessel, using multiple acoustic transducers mounted on the pill‟s surface. The thesis suggests strategies for placement, excitation and synchronisation of the transmitters on the pill and receivers on the vessel wall to deliver 3D localisation. Motivation for the project has emerged from the desire to develop wireless sensor networks to monitor the internals of industrial processes. A major challenge relates to the ability to accurately determine the location of the pill within the vessel, in the presence of multipath reflections. The main challenges relate to the determination of suitable transmission methodologies and synchronisation strategies to allow accurate localisation. The pill has to be a finite size in order to contain the required sensor hardware and transducers must be mounted on the surface of the pill such that signals are able to propagate directly to receivers on the vessel wall. This presents challenges in optimising the transmitter and receiver layout to maximise signal strength and also to determine how the separation of multiple transmitters on the pill impacts localisation accuracy. Time-Difference-of-Arrival (TDOA) has been investigated as a localisation technique, with simulations revealing that the separation of transmitters on the pill influences the accuracy. By modifying the standard TDOA equations with offset knowledge it has been demonstrated, in simulation, that this error can be reduced and by uniquely coding transmitters it is possible to resolve rotation of the pill in the vessel allowing further reduction in localisation error. Simulations have investigated how the location of receivers on the vessel wall influences the localisation error when the TDOA values are compromised by noise. It has been demonstrated that by mounting receivers at the extremities of the vessel the localisation error of the pill can be reduced. Work has also been undertaken to characterise both the vessel reflection properties and also the transmitter beam profile to allow a suitable transmitter layout on the pill to be determined. Simulations, supported by experimental results, have shown that a curved vessel surface can focus the reflected signals and therefore compromise peak detection signal methodologies. As a result amplitude thresholding is suggested for detecting received signals. The research is substantiated with a simple demonstrator that suggests, for both Time-of-Flight (TOF) and Time-Difference-of-Arrival techniques, that the location of the pill can be determined with an accuracy of ± 5 cm throughout a 250 litre vessel. This is the first time that underwater localisation in a confined space using multiple transmitters on the surface of a sensor “pill” has been reported.

La combustion sans flamme est un régime de combustion massivement dilué associant forte efficacité énergétique et très faibles émissions polluantes dans les fours industriels. La composition du combustible et la température des parois de la chambre de combustion sont deux paramètres très influents de ce régime. Dans de précédents travaux menés au CORIA, l’étude du régime de combustion sans flamme des mélanges méthane-hydrogène à 18% d’excès d’air a mené à des résultats originaux et prometteurs. D’autre part, la haute température des parois s’est avérée un élément primordial pour la stabilisation de la combustion sans flamme. Dans le cadre du projet CANOE en collaboration avec GDF SUEZ et l’ADEME, cette thèse a pour objectif, d’une part de compléter l’étude de l’extension de ce régime à des mélanges méthane-hydrogène pour des conditions opératoires plus proches des conditions classiques de fonctionnement de brûleurs (10% d’excès d’air), et d’autre part, d'étudier les problèmes de stabilité de la combustion sans flamme en environnement à basse température pour envisager son application à des configurations de type chaudière industrielle.Sur le four pilote à hautes températures de parois du CORIA, l’ajout de l’hydrogène dans le combustible a permis de garder le régime de combustion sans flamme pour toutes les proportions méthane - hydrogène avec très peu d’émissions polluantes. Une augmentation de l’excès d’air est toutefois nécessaire pour certaines conditions opératoires. Les expériences réalisées avec abaissement progressif de la température des parois ont permis d’étudier l’influence de celle-ci sur le développement de la combustion sans flamme, et d’atteindre les limites de stabilité de ce régime. Des résultats similaires sont obtenus sur une installation semi-industrielle de GDF SUEZ. L’ajout d’hydrogène rend la combustion sans flamme moins sensible à l’abaissement de la température de parois. Une étude analytique de jets turbulents confinés a été développée pour représenter l'interaction entre les jets de réactifs et leur environnement dans la chambre de combustion permettant d'atteindre le régime de combustion sans flamme par entraînement, dilution et préchauffage. Ce modèle nous a permis d’établir une étude systématique permettant de mettre en valeur l’effet de chaque paramètre sur le développement des jets dans l’enceinte, et ainsi servir de moyen de pré-dimensionnement de brûleur à combustion sans flamme. L'apport de chaleur nécessaire à la stabilisation à basse température a ainsi été estimé. Sur cette base, un brûleur adapté aux configurations à parois froides a été dimensionné et fabriqué. L’applicabilité de la combustion sans flamme avec ce brûleur dans une chambre de combustion à parois froides, spécialement conçue et fabriquée dans cet objectif au cours de cette thèse, a été étudiée. Un régime de combustion diluée à basses températures a pu être stabilisé, mais le fort taux d'imbrûlés produits en sortie reste à réduire. / Mild flameless combustion is a massively diluted combustion regime associating high energy efficiency and very low pollutant emissions from industrial furnaces. The fuel composition and walls temperature are two very influential parameters of this combustion regime. In previous works realized at CORIA, flameless combustion of methane - hydrogen mixtures at 18% of excess air has shown very promising results. In another hand, high walls temperature is an essential element for flameless combustion stabilization. Within the framework of the project CANOE in collaboration with GDF SUEZ and ADEME, the objective of this PhD thesis is to complete the study of flameless combustion for methane-hydrogen mixtures in operating conditions similar to classical operating conditions of burners (10% of excess air), and in another hand, to study the stability limits of this combustion regime in low temperature environment like in industrial boiler.Experiments realized on the CORIA high temperature pilot facility, have proved that hydrogen addition in the fuel keep flameless combustion regime stable for all methane - hydrogen proportions, with very ultra-low pollutant emissions. An increase of excess air is however necessary for some operating conditions.Experiments realized with wall temperature progressive decrease allowed to study the influence of this parameter on flameless combustion, and to reach its stability limits. Similar results are obtained on the semi-industrial facility of GDF SUEZ. With hydrogen addition, flameless combustion is less sensitive to wall temperature decrease. An analytical representation of confined turbulent jets has been then developed to represent interaction between the reactant jets and their environment in the combustion chamber allowing reaching fameless combustion regime by entrainment, dilution and preheating. The effect of each parameter on the development of the jets can be then studied, which can be used as convenient tool of flameless combustion burners design. The heat quantity necessary for the low wall temperature stabilization has been quantified. On this base, a burner adapted to the configurations with cold walls has been designed. The applicability of the flameless combustion with this burner has been studied in a combustion chamber with low wall temperature specially designed for this purpose during this thesis. A mild diluted combustion regime has been achieved, but the high levels of unburnt gases have to be reduced.

Mit der vorliegenden Arbeit wurde ein Beitrag zur Klärung des Querkrafttragverhaltens von Wandscheiben im Mauerwerksbau geleistet. Die Untersuchungen umfassten hierbei analytische, numerische und versuchstechnische Betrachtungen. Als Grundlage für die Untersuchungen wurden FE-Elemente und FE Materialroutinen, die auf die Materialspezifik des Mauerwerks abgestimmt sind, entwickelt und in das Programmsystem ANSYS implementiert. Als wesentliche Eingangsgrößen sowohl für die analytischen als auch die numerischen Berechnungen werden diverse Materialparameter benötigt. Neben den üblichen Materialversuchen sind weiterführende Betrachtungen zu den „Kleinversuchen“ angestellt worden. Für einige Materialparameter waren numerische Rückrechnungen, wie z.B. für die Keilspaltversuche, erforderlich. Für ein breites Spektrum an Materialien, angefangen beim Ziegel über Mörtel bis zum Lehm, konnten wesentliche Werte ermittelt werden. Die vorhandenen analytischen Modelle der Schubfestigkeit wurden im Rahmen der vorgelegten Arbeit weiterentwickelt. Nach der Herleitung neuer Gleichungen galt es, diese für die Anwendung zu vereinfachen. Es sind auch numerische Modelle erläutert, die einen minimierten Wandausschnitt darstellen und mit denen eine direkte Berechnung der Schubfestigkeit möglich ist. Neben der Schubfestigkeit des Mauerwerks haben auch die Wandgeometrie und die Einbindung der Wand in das Gebäude Einfluss auf die maßgebende Querkrafttragfähigkeit. Zu deren Berücksichtigung werden wiederum Ingenieurmodelle benötigt, deren Komponenten hier eingehender betrachtet wurden. Als Grundlage dienten weitere Versuche basierend auf dem Modell der Aussteifungswand im Gebäude. Sowohl aus den analytisch gewonnenen Gleichungen als auch aus den an den Versuchen kalibrierten Gleichungen sind Lösungen für die Normung entwickelt worden. Diese beinhalten neben Gleichungen für das genaue Verfahren auch stark vereinfachte Bemessungslösungen mit tabellarisch aufbereiteten Mindestquerschnitten für die Aussteifungswände.

In this work, an in-depth analysis of crystalline characteristics has been performed for a unique set of strictly monodisperse poly-ε-caprolactone (PCL) oligomers. The molecules have different sets of end groups with various degrees of bulkiness and hydrogen bonding potential, affecting their aptitude to pack in ordered crystal structures. The oligomers also have different numbers of repeating units (n = 2-64), affecting the degree to which end groups influence overall molecular characteristics. The presence of bulky end groups leads to an innate confinement effect on crystallisation which in turn makes it possible to utilize the set of PCL oligomers to study confined space crystallisation. Confined space crystallisation is explored as a route to gain further understanding about the early metastable phases in crystal formation.   The monodisperse nature of the samples made it possible to collect very precise small-angle and wide-angle X-ray scattering data (SAXS and WAXS) as well as calorimetric data. Computer modeling studies were performed to support experimental findings. It was shown that end groups strongly affected crystallisation features for the shorter oligomers (n ≤ 8) but to a lesser extend for the longer oligomers (n ≥ 16). The presence of a bulky end group at one end of an oligomer could inhibit the formation of hydrogen bonds on the other end. Short oligomers (n = 8) with OH-end groups exhibited novel packing characteristics. At one isothermal crystallisation temperature the molecules exhibited not only lamellar ordering but also an additional, likely rectangular or slanted, ordering. The sample was packed in a unique structure with molecular chains lying parallel but not aligned head to head with each other. At a higher crystallisation temperature the molecules packed in a double layered structure and at an even higher temperature in a typical non-folded but tilted single-molecular layer pattern.   Unit cell determination was performed for a short oligomer with two bulky end groups, showing the existence of a tetragonal unit cell with different dimensions than the orthorhombic unit cells previously reported for linear PCL without end groups. To gain greater insight into the earliest stages of molecular packing, in situ WAXS measurements were performed using a synchrotron radiation beam and measuring data each 12 s whilst very slowly going from melt to isothermal crystallisation. It was shown that the crystal unit cell was distorted during the first minutes of slow crystallisation, which might either represent a metastable phase or else a highly distorted orthorhombic phase. / QC 20101105