<p>The focus of this work is to develop and employ numerical methods that provide characterization of granular microstructures, dynamic fragmentation of brittle materials, and dynamic fracture of three-dimensional bodies.</p><p>We first propose the fabric tensor formalism to describe the structure and evolution of lithium-ion electrode microstructure during the calendaring process. Fabric tensors are directional measures of particulate assemblies based on inter-particle connectivity, relating to the structural and transport properties of the electrode. Applying this technique to X-ray computed tomography of cathode microstructure, we show that fabric tensors capture the evolution of the inter-particle contact distribution and are therefore good measures for the internal state of and electronic transport within the electrode. </p><p>We then shift focus to the development and analysis of fracture models within finite element simulations. A difficult problem to characterize in the realm of fracture modeling is that of fragmentation, wherein brittle materials subjected to a uniform tensile loading break apart into a large number of smaller pieces. We explore the effect of numerical precision in the results of dynamic fragmentation simulations using the cohesive element approach on a one-dimensional domain. By introducing random and non-random field variations, we discern that round-off error plays a significant role in establishing a mesh-convergent solution for uniform fragmentation problems. Further, by using differing magnitudes of randomized material properties and mesh discretizations, we find that employing randomness can improve convergence behavior and provide a computational savings.</p><p>The Thick Level-Set model is implemented to describe brittle media undergoing dynamic fragmentation as an alternative to the cohesive element approach. This non-local damage model features a level-set function that defines the extent and severity of degradation and uses a length scale to limit the damage gradient. In terms of energy dissipated by fracture and mean fragment size, we find that the proposed model reproduces the rate-dependent observations of analytical approaches, cohesive element simulations, and experimental studies.</p><p>Lastly, the Thick Level-Set model is implemented in three dimensions to describe the dynamic failure of brittle media, such as the active material particles in the battery cathode during manufacturing. The proposed model matches expected behavior from physical experiments, analytical approaches, and numerical models, and mesh convergence is established. We find that the use of an asymmetrical damage model to represent tensile damage is important to producing the expected results for brittle fracture problems.</p><p>The impact of this work is that designers of lithium-ion battery components can employ the numerical methods presented herein to analyze the evolving electrode microstructure during manufacturing, operational, and extraordinary loadings. This allows for enhanced designs and manufacturing methods that advance the state of battery technology. Further, these numerical tools have applicability in a broad range of fields, from geotechnical analysis to ice-sheet modeling to armor design to hydraulic fracturing.</p> / Dissertation

Lors de cette thèse, je me suis servis du modèle de la Galaxie de Besançon (BGM), modèle développé dans ce laboratoire depuis plusieurs années.Ce modèle, fortement utilisé par la communauté internationale (papier de référence Robin, Reylé et al, 2003, cité plus de 1250 fois), a été choisi comme modèle de référence dans la préparation de la mission spatiale de l’ESA Gaia.Ce modèle est un outil puissant pour étudier notre Galaxie car il permet de simuler statistiquement son contenu en étoiles. Ce contenu dépendant d'hypothèses émies sur la forme et l'histoire de la Voie Lactée.Ici, je me concentre sur une population de la Voie Lactée particulière, le disque épais (un ensemble d'étoiles vieilles qui représente environ 30% des étoiles de notre Voie Lactée).A l'aide du BGM, il est possible d’essayer de mieux comprendre sa forme et son histoire. La méthode utilisée pendant cette thèse est la comparaison d'observations avec les simulations du BGM et d'un ajustement des propriétés du disque épais à l'aide d’une méthode basée sur le principe des chaînes de Markov - Monte Carlo (MCMC). / During my Phd thesis, I have used the Besançon Galaxy's Model (BGM) developed in my laboratory for many years.This model is widely use by astrophysicist around the world (the reference article is Robin, Reylé et al, 2003 and is cited more than 1250 times) and have been chose to be the reference model to prepare ESA's space mission Gaia.The BGM allow us to study our Galaxy by simulating statistically her stellar content. This stellar content is depending of hypothesis for the shape and history of the Milky Way.Here, I focus on the Milky Way's thick disc (old stars representing about 30 % of the total stellar content of the Milky Way).Thanks to the BGM, we can try to understand the shape and history of the thick disc. During this thesis, I've compared observation and simulations made by the BGM and adjusted the thick disc properties by using a Markov chain of Monte Carlo (MCMC).

Diante da necessidade de melhorar a produção de culturas anuais em regiões que enfrentam adversidades hídricas, a utilização dos hidrogéis surgem como condicionadores de água no solo, atuando como reserva de água para a planta, e disponibilizando a mesma em momentos de estresse hídrico, melhorando o desenvolvimento e produtividade das plantas. Desta forma, o estudo foi dividido em três capítulos, no primeiro avaliou-se a eficiência da utilização do hidrogel na retenção e disponibilização de água para o desenvolvimento e produção da cultura do feijão Caupi quando submetido a estresse hídrico. Foram avaliados 4 polímeros e 5 concentrações na cultura do feijão caupi, em casa de vegetação. O segundo e terceiro capítulos foram realizados em campo, avaliando-se 2 polímeros e cinco concentrações para a cultura do feijão caupi e soja safra 2015/2016. Conclui-se que o uso de polímeros mostrou-se, para as condições avaliadas, como potencial alternativo para redução de perdas de produtividade resultantes da ação do estresse hídrico. / Facing of the need to improve the production of annual crops in regions undergo through water adversities, the use of hydrogels appears as water conditioner in the soil, acting as a water reserve for the plant, and making it available in times of water stress, on the first chapter. Thus, the study was divided in three chapters. In chapter one efficiency of hydrogel utilization on the retention and availability of water for the development and production of the Caupi bean culture when submitted to water stress was evaluated, thereby 4 polymers and 5 concentrations in cowpea, under greenhouse conditions were evalvated. The second and third chapters were conducted on the field, evaluating 2 polymers and five concentrations for 2015/2016 cowpea and soybean crops. It is concluded that the use of polymers was shown, for the evaluated conditions as an alternative potential to reduce productivity losses resulting from the action of water stress.

O Tocantins que antes adotava a silvicultura como uma alternativa, atualmente já se encontra em crescente avanço sendo considerado como uma das maiores fontes de renda do estado. Diante disso alguns fatores como as alterações das condições edafoclimáticas podem prejudicar o crescimento e o desenvolvimento de alguns vegetais. O crescimento das plantas está associado a vários fatores fisiológicos e bioquímicos, que são controlados e influenciados pela particularidade genética de cada espécie e pelas condições ambientais. Visando investigar os mecanismos adaptativos da espécie de Acacia mangium Willd. principalmente aqueles relacionados à baixa disponibilidade hídrica, o presente trabalho tem como objetivo avaliar as respostas fisiológicas, bioquímicas e a tolerância da espécie Acacia mangium Willd. expostas à deficiência hídrica e a reidratação. Dois experimentos foram instalados. Os experimentos foram conduzidos em ambiente protegido na Estação Experimental da Universidade Federal do Tocantins, Campus de Gurupi-TO. Utilizaram-se mudas com 180 dias de idade, as quais foram transferidas para vasos de polietileno com capacidade de 5,5 litros. O delineamento estatístico utilizado nos dois experimentos foi inteiramente casualizado (DIC), representado por quatro tratamentos hídricos (100; 60; 40 e 30% da capacidade de campo) com 12 repetições. O primeiro experimento as plantas foram mantidas sob déficit hídrico durante os 25 dias de experimento. O segundo experimento as plantas foram reidratadas após um curto período de estresse hídrico de 6 dias, elevando todos os níveis de agua para 100% da capacidade de campo, sendo avaliadas durante os 25 dias de experimento. Durante o período experimental, foram realizadas avaliações em relação às trocas gasosas, potencial hídrico foliar, teor relativo de água, atividade de enzimas antioxidantes, prolina, e massas secas das folhas, caule, raiz e total. O estresse hídrico em condições de 40 e 30% da capacidade de campo por vinte e cinco dias influenciou a regulação das relações hídricas das mudas de Acacia mangium Willd., reduzindo o potencial hídrico foliar, condutância estomática, transpiração, eficiência da carboxilação (A/CI) e eficiência do uso da água (EUA) para garantir o funcionamento dos processos bioquímicos e metabólicos. A exposição das mudas nas condições de 60% da capacidade de campo não afetou negativamente a assimilação líquida (A), visto que não houve grande variação comparada à testemunha com 100% da capacidade de campo. A Acacia mangium Willd. é moderadamente tolerante a baixos níveis de água no solo. Na produção de matéria seca em mudas de Acacia mangium Willd. a variável mais sensível à deficiência hídrica foi à massa seca das folhas e do caule. O tratamento com maior déficit hídrico com 30% da capacidade de campo apresentou o acúmulo maior do teor de prolina. É uma especie que em condições de seis dias sob estresse hídrico, ainda é capaz de recuperar o desempenho fisiológico, caracterizando a sua plasticidade fisiológica e bioquímica na fase de muda. Para a espécie de Acacia mangium Willd., a catalase foi a principal enzima em combater o estresse oxidativo quando submetida a déficit hídrico. / Tocantins, which once adopted forestry as an alternative, is already in the process of being announced as one of the state's largest sources of income. Faced with this, factors such as the conditions of edaphoclimatic conditions may hinder the growth and development of some plants. Plant growth is associated with several physiological and biochemical factors, which are controlled and influenced by genetic specificity of each species and environmental issues. Aiming to investigate the adaptive mechanisms of the Acacia mangium Willd species. The main sources related to availability, as well as the evaluation of the physiological, biochemical and tolerance of the species Acacia mangium Willd. exposed to water deficiency and rehydration. Two experiments were installed. The experiments were conducted in a protected environment at the Experimental Station of the Federal University of Tocantins, Campus of Gurupi-TO. Seedlings with 180 days of age were used, as were transferred to 5.5 liter polyethylene vessels. The statistical design used in the two experiments was completely randomized (DIC), represented by four water treatments (100, 60, 40 and 30% of field capacity) with 12 replications. The first experiment as plants were kept under water deficit during the 25 days of experiment. The second experiment as plants were rehydrated after a short period of water stress of 6 days, raising all water levels to 100% of the field capacity, being evaluated during the 25 days of experiment. During the experimental period, a specialized journal on gas exchanges, potential water leaflet, water content, activity of antioxidant enzymes, proline and dry leaf, stem, root and total masses was carried out. Water stress at 40 and 30% field capacity for 25 days influenced the water relations of Acacia mangium Willd., Reducing leaf water potential, stomatal conductance, transpiration, carboxylation efficiency (A / CI) and energy efficiency (US) to ensure the functioning of biochemical and metabolic processes. Exposure of the seedlings at 60% field capacity did not negatively affect the net assimilation (A), since there was not much variation compared to the control with 100% field capacity. The Acacia mangium Willd. is moderately tolerant to low levels of non-soil water. On the production of dry matter in seedlings of Acacia mangium Willd. a variable more sensitive to water deficit for the dry mass of the leaves and the stem. The treatment with higher water deficit with 30% of the field capacity presented the highest accumulation of the proline content. It is a species under conditions of six days under water stress, it is still able to recover the physiological performance, characterizing its physiological and biochemical plasticity in the molting phase. For a species of Acacia mangium Willd., A catalase for a major enzyme in combating oxidative stress when submitted to water deficit.

Aços de alta resistência e baixa liga (HSLA) tem sido amplamente empregados na indústria nos últimos anos, em especial na indústria automotiva, com a finalidade de reduzir peso dos produtos sem prejudicar características importantes como a resistência. O aço LNE 380 vem sendo aplicado na fabricação de peças mais robustas e que passam por processos de dobra. Dessa forma, esse estudo tem como objetivo principal determinar as deformações máximas causadas pelas tensões de tração em chapas do aço de alta resistência e baixa liga NBR 6656 LNE 380 submetidas ao processo de dobramento. Chapas de 6,35mm de espessura foram inicialmente analisadas por meio de ensaios de tração para verificar as propriedades mecânicas do aço. Os ensaios de tração apresentaram uma tensão de escoamento de 469±8MPa e tensão máxima de resistência de 539±3MPa. O ensaio de dobramento semiguiado foi utilizado para detectar o nível de deformação na região externa das chapas, ocasionado pelos esforços de tração durante o processo, bem como seu retorno elástico. No ensaio de dobramento utilizaram-se três raios de punçãovariando o deslocamento do mesmo para se obter diferentes raios de dobra. As máximas deformações relativa e verdadeira foram medidas na região externa da dobra, e posteriormente comparadas com resultados teóricos a fim de validar equações indicadas na bibliografia. Os valores teóricos variaram conforme o raio do punção, diferente do observado nos ensaios, onde a deformação permaneceu a mesma para todos os três raios utilizados. A maior deformação, calculada e medida, refere-se ao ensaio realizado com o menor raio de punção, assim como o maior Fator de Retorno Elástico. Verificou-se que no ensaio de dobramento, para o aço LNE 380, nas condições pré-definidas, a variação do raio do punção não interferiu de forma significativa nos resultados, uma vez que, as deformações e retorno elástico medido obteram valores próximos para diferentes raios. / High Strength Low Alloy (HSLA) steels have been widely used in the industry in the last years, especially in the automotive industry, in order to reduce weight products without impairing important characteristics such as strenght. The LNE 380 steel has been applied in the manufacture of more robust parts and that go through bending process. Therefore, this study has as main objective to determine the maximum deformation caused by the tensile stresses in sheets of High Strength Low Alloy steel NBR 6656 LNE 380 submitted to bending process. Sheets of 6,35mm thick were initially analyzed by tensile tests to verify the mechanical properties of the steel. The tensile tests showed a yield stress of 469±8 and maximum tensile strength of 539±3. The semi-guided bending test was used to detect the level of deformation in the external fibers of the sheets, caused by tensile stresses during the process, as well as their springback. Three punch radii were used in the bending test varying their displacement to achieve different bending radii. The maximum relative and true deformations were measured in the outer region of the bend, and subsequently compared with theoretical results in order to validate equations used in the bibliography. The theoretical values varied according to the punch radius that was different from those observed in the tests, where the deformation remained the same for all three radii used. The largest deformation calculated and measured refers to the test performed with the smallest punch radius, as well as the largest springback fator. It was observed that in the bending process, for the LNE 380 steel, under the pre-defined conditions, the variation of the punch radius did not interfein the results significally, since the values of deformation and springback measured were similar for different radii.

Over the past few decades, fluorescence microscopy has proven to become the most widely used imaging technique in the field of life sciences. Unfortunately, all classical optical microscopy techniques have one thing in common: their resolution is limited by the diffraction. Thankfully, due to the very strong interest, development of fluorescent microscopy techniques is very intense, with novel solutions surfacing repeatedly. The major breakthrough came with the appearance of super-resolution microscopy techniques, enabling imaging well below the diffraction barrier and opening the new era of nanoscopy. Among the fluorescent super-resolution techniques, Stimulated Emission Depletion (STED) microscopy has been particularly interesting, as it is a purely optical technique which does not require post image processing. STED microscopy has proven to resolve structures down to the molecular resolution. However, super-resolution microscopy is not a cure to all the problems and it also has its limits. What has shown to be particularly challenging, was the super-resolution imaging of thick samples. With increased thickness of biological structures, the aberrations increase and signal-to-noise (SNR) decreases. This becomes even more evident in the super-resolution imaging, as the nanoscopic techniques are especially sensitive to aberrations and low SNR. The aim of this work is to propose and develop a 3D STED microscope that can successfully image thick biological samples with nanoscopic resolution. In order to achieve that, adaptive optics (AO) has been employed for correcting the aberrations, using the indirect wavefront sensing approach. This thesis presents a custom built 3D STED microscope with the AO correction and the resulting images of thick samples with resolution beyond diffraction barrier. The developed STED microscope achieved the resolution of 60nm in lateral and 160nm in axial direction. What is more, it enabled super-resolution imaging of thick, aberrating samples. HeLa, RPE-1 cells and dopaminergic neuron differentiated from human IPS cells were imaged using the microscope. The results shown in this thesis present 3D STED imaging of thick biological samples and, what is particularly worth to highlight, 3D STED imaging at the 80μm depth, where the excitation and depletion beams have to propagate through the thick layer of tissue. 3D STED images at such depth has not been reported up to date.

Abstract The main objective of this thesis was to research the integration of novel materials and fabrication processes into Low Temperature Co-fired Ceramic (LTCC) technology; enabling fabrication of Radio Frequency (RF) and microwave components with advanced performance. The research focuses on two specific integration cases, which divide the thesis into two sections: the integration of tunable dielectric structures and the integration of air filled waveguides. The first section of the thesis describes the development and characterization of low sintering temperature Barium Strontium Titanate (BST) thick film paste. Sintering temperature of BST is decreased from approximately 1350 °C down to 900 °C by lithium doping and pre-reaction of the doped composition. This allows the co-sintering of the developed BST paste with commercial LTCC materials. Additionally two integration techniques to embed tunable components in an LTCC substrate using the developed BST paste are also presented and the electrical performance of the components is evaluated. The highest measured tunability value was 44% with a bias field of 5.7 V/µm. The permittivity of the films varied between 790 and 190, and the loss tangent varied between 0.004 and 0.005, all measured unbiased at 10 kHz. The developed LTCC compatible BST paste and the presented integration techniques for tunable components have not been previously published. In the second section of the thesis, a fabrication method for the LTCC integrated air-filled rectangular waveguides with solid metallic walls is presented. The fabrication method is described in detail and implemented in a set of waveguides used for characterization. A total loss of 0.1–0.2 dB/mm was measured over a frequency band of 140–200 GHz. The electrical performance of the waveguides is evaluated and their use demonstrated in an integrated LTCC antenna operating at 160 GHz.

Origami has been investigated and demonstrated for engineering applications in recent years. Many techniques for accommodating the thickness of most engineering materials have been developed. In this work, tables comparing performance and manufacturing characteristics are presented. These tables can serve as useful design tools for engineers when selecting an appropriate thickness-accommodation technique for their application. The use of bent sheet metal for panels in thick-origami mechanisms shows promise as a panel design approach that mitigates several trade-offs between performance and manufacturing characteristics. A process is described and demonstrated that can be employed to use sheet metal in designs of origami-adapted mechanisms that utilize specific thickness-accommodation techniques. Data structures based on origami can be useful in the automation of thick-origami mechanism design. The use of such data structures is explained and shown in the context of a program that will automatically create the 3D CAD models and assembly of a thick-origami mechanism using the tapered panels technique based on the input origami crease pattern. Manufacturability in the design of origami-adapted mechanisms is discussed through presenting and examining three examples of origami-adapted mechanisms. As the manufacturability of origami-adapted products is addressed and improved, their robustness will also improve, thereby enabling greater use of origami-adapted design.

Includes bibliographical references (leaves 150-161). Documents the historical distribution and subsequent decline of bush stone-curlews in South Australia, determines their current distribution and status on Kangaroo Island, their home range sizes and movements, the characteristics of foraging habitat, day roost areas and nest sites and the availability of habitat, the diet and food resources, and potential threats to the population. As a result of the findings of this survey, bush stone-curlews have been downgraded from endangered to vulnerable in South Australia.

<p>Like the rest of the society modern health care has to deal with the ever increasing information flow. Imaging modalities such as CT, MRI, US, SPECT and PET just keep producing more and more data. Especially CT and MRI and their 3D image stacks cause problems in terms of how to effectively handle these data sets. Usually a PACS is used to manage the information flow. Since a PACS often is implemented with a server-client setup, the management of these large data sets requires an efficient representation of medical image stacks that minimizes the amount of data transmitted between server and client and that efficiently supports the workflow of a practitioner.</p><p>In this thesis an efficient wavelet representation for large medical image stacks is proposed for the use in a PACS. The representation supports features such as lossless viewing, random access, ROI-viewing, scalable resolution, thick slab viewing and progressive transmission. All of these features are believed to be essential to form an efficient tool for navigation and reconstruction of an image stack.</p><p>The proposed wavelet representation has also been implemented and found to be better in terms of memory allocation and amount of data transmitted between server and client when compared to prior solutions. Performance tests of the implementation has also shown the proposed wavelet representation to have a good computational performance.</p>