Orientador: Inácio Maria Dal Fabbro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-22T14:06:58Z (GMT). No. of bitstreams: 1 Cardoso_KelenCristiane_M.pdf: 10447047 bytes, checksum: bd1de8c6f17c3f3f8e755c78ecee3801 (MD5) Previous issue date: 2013 / Resumo: A determinação de tensões e deformações é amplamente empregada na engenharia. Métodos clássicos de extensometria elétrica, extensometria mecânica e simulações por elementos finitos são úteis e permitem qualificar e quantificar a distribuição de carga em elementos de extrutura. Estudos fotoelásticos vêm ganhando cada vez mais espaço, pois facilitam a determinação e permitem a visualização da distribuição de tensões no espécimen em estudo de maneira rápida e confiável. As técnicas de moiré de sombra e projeção são os métodos mais comumente utilizados devido principalmente à simplicidade e rapidez de medição, tornando-os objeto de frequentes estudos em vários tipos de aplicações. A vantagem de se utilizar as técnicas de moiré está associada à simplicidade dos equipamentos necessários, simplicidade de aquisição e processamento de imagens, além de ser adequadas ao estudo de corpos de geometria simples ou complexa. A proposta deste trabalho se identifica em qualificar e quantificar as distribuições de deformação e tensão em uma mola membrana, como elemento de máquina de geometria complexa pela aplicação de técnica de moiré. Para este trabalho foi escolhido à mola membrana como elemento de máquina de geometria complexa, sendo um elemento de papel muito importante na montagem do conjunto de embreagem, pois o desalinhamento das linguetas pode resultar em trepidação ou vibração no pedal, gerando dificuldade de acionamento do mecanismo, podendo gerar também deformações dos componentes, e com isso desgaste prematuro do sistema em pauta. O deslocamento da mola membrana no acionamento da embreagem promove uma alteração na distribuição de tensão e deformação em seu perfil assim como nos componentes associados à mola, e o desalinhamento das linguetas faz com que essa distribuição não seja uniforme. A técnica de moiré de sombra pode auxiliar a simulação para determinar a deformação, a tensão bem como a distribuição de pressão sobre a superfície da mola membrana. A simulação computacional por elementos finitos e a técnica de extensometria com strain gauges, será utilizado como base de comparação entre os resultados obtidos por moiré de forma a proporcionar uma validação da técnica em estudo em elementos mecânicos de geometria não simples / Abstract: A diaphragm spring was chosen as a machine element of complex geometry, which integrates the clutch assembly. The tabs misalignment may result in vibrations transmitted to the clutch system, as well as difficulties in driving the pedal and can also generate components deformation and thus premature wearing of the whole clutch system. The displacement of the diaphragm spring during clutch driving promotes alterations on the stress and strain distribution on its profile as well as on the components associated to the spring, and tabs misalignment turns this distribution not uniform. The determination of stress and strain is widely used in engineering. Classical methods as electrical strain gage, mechanical gage and finite element simulations are useful to the qualification and quantification of load distribution in the specimens. Photoelastic techniques are gaining space, because it facilitates the stress and strain distribution determination, allowing clear visualization of the undergoing phenomena based on a quick and reliable experimentation. The shadow moiré and projection moiré techniques are the most commonly used methods primarily due to its measurement simplicity and quickness which supports frequent studies and proposed applications. The advantage of using moiré techniques is associated to the requirement of simple experimental setup for image acquisition and processing as well as its application to bodies of simple or complex geometry. The purpose of this study was to apply a moiré technique to obtain the stress and strain qualification and quantification on a spring membrane taken as a machine component of complex geometry. The shadow moiré technique can assist the simulation to determine the strain and stress distribution on diaphragm spring surface. The computer simulation by finite element technique and strain gauges, were used as the basis of comparison between the results obtained by the moiré method to validate the application of the proposed optical method to study of mechanical elements of complex geometry / Mestrado / Maquinas Agricolas / Mestra em Engenharia Agrícola

De nos jours, la radiographie est l'examen de référence pour le suivi des pathologies de la colonne vertébrale. La radiographie bi-planaire permet de plus, par reconstruction 3D, d’évaluer la configuration spatiale de la colonne vertébrale. Cependant, les expositions radiographiques répétées entrainent une augmentation du risque de cancer. Une solution pour réduire les doses de radiation peut être de remplacer certains examens radiographiques par une mesure de la surface du dos. Cette mesure non-invasive permet, entre autre, d’obtenir un grand nombre de paramètres cliniques utiles pour le diagnostic et le suivi des pathologies. Cette mesure permet également d’estimer la configuration du rachis si l’on met en place une modélisation biomécanique adaptée. Le travail réalisé dans cette thèse consiste à développer et mettre en oeuvre une telle modélisation basée sur les informations personnalisées à la fois internes et externes. Le dispositif Biomod 3S (développé par la société AXS Ingénierie, Bordeaux) offre la possibilité d’une acquisition simultanée de radiographies et de surfaces du dos par franges de Moiré. Cette acquisition sur une quinzaine de sujets scoliotiques (des Hôpitaux Universitaires de Bordeaux) a notamment permis d’évaluer les relations entre plusieurs paramètres 3D internes (e.g., la rotation axiale des vertèbres) et de nombreux paramètres 3D externes (e.g., les gibbosités et flèches). Cette acquisition simultanée permet également de prédire la nouvelle configuration de la colonne vertébrale dans une seconde posture où seule la mesure de surface du dos est effectuée. Pour cela, la modélisation en multi-corps rigides articulés qui a été développée (sous Scilab) utilise (a) la géométrie personnalisée de la colonne vertébrale reconstruite dans la première posture et (b) des contraintes issues de la mesure de la surface du dos dans les deux postures (e.g., position de C7). Le modèle a pu être validé sur une dizaine de sujets sains dont la colonne vertébrale et la surface du dos ont été reconstruits en 3D dans différentes positions (debout, penché en avant) à l’aide d’un IRM positionnel. Le modèle a pu également être exploité sur quelques sujets pathologiques. Ce travail, qui a exploré et exploité de nombreuses informations 3D internes et externes, ouvre des perspectives pour le diagnostic et le suivi non-invasif des pathologies de la colonne vertébrale / Nowadays, radiography is the gold standard for the follow up of spinal pathologies. Furthermore, bi-planar radiography allows the assessment of vertebrae configuration, by 3D reconstruction. However, multiple radiographic examinations during childhood and adolescence increase the risk of breast cancer among women. To reduce radiation doses, some radiographic assessments could be replaced by the back surface evaluation. This kind of non-invasive procedure allows for acquisition of many clinical parameters useful for spinal pathologies diagnosis and follow-up. Moreover, with an appropriate biomechanical model, the back surface measurements could be used to estimate the spine configuration. The aim of this thesis is to develop and implement such a model based on personalized internal and external data. The Biomod 3S device has been developed by the company AXS MEDICAL SAS, Bordeaux, France. It offers the possibility of simultaneous acquisitions of X-rays and Moiré fringes to obtain 3D reconstructions of the spine and the back surface. Such acquisitions on fifteen scoliotic subjects have enabled us to assess several relationships between internal 3D parameters (for example axial rotation of vertebrae) and external 3D parameters (for example rib hump). The spine configuration and the back surface obtained during this acquisition will also be used as initial position to develop (with Scilab) the multi-body model. The other data used by the model are the back surface in a second position and constraints obtained from the surface in both positions (for example displacement of C7 vertebra). The model has been validated on nine healthy subjects, whose 3D spine and back surface were reconstructed in several positions (standing, leaning forward, sitting) from MRI acquisitions. Moreover, the model has been operated on a pathological subject. This work has explored and utilized many spine and back surface information and leads the way to non-invasive diagnosis and follow-up of spinal disease

One of the basic problems in computer vision is motion detection and analysis in a given scene. This work focuses on detecting small changes in the image by using the moiré phenomenon. The main goal of this thesis is to detect different types of dislocations with algorithms used in computer vision. In this work synthetically created pictures are analysed, which were created with the mathematical model of a pinhole camera.

The end-member types of shallow magmatic intrusions comprise cone sheets and dykes. These propagate from their source magma chamber towards the Earth’s surface. The propagation of magma within the shallow part of the volcano plumbing system produces surface deformation and seismicity, signs of volcanic unrest. Studying surface displacement using GPS and InSAR, geodetic modelling, fitting modelled data to real displacements, and inversion is regularly used to understand the processes in the subsurface. There is no possibility in nature to validate the assumptions of these models. However, using analogue modelling, it is possible to reproduce cone sheets and dykes in a controlled environment and study the associated surface deformation. This thesis tests the hypothesis that the two end-member types of magmatic sheet intrusions produce specific patterns of surface deformation. The analogue model surface is documented using two different monitoring setups: moiré monitoring and photogrammetry. The moiré method (dataset 1) consists of 43 experiments, 19 of which were dykes, 22 were cone sheets, and 2 were classified as hybrids. Photo- grammetry (dataset 2) was applied in 8 experiments, 3 of which produced cone sheets and 5 dykes. Dataset 1 successfully identified surface deformation patterns specific to the two intrusion types. Cone sheets develop in a gradual linear fashion, while the dykes exhibit a two-phase behaviour. The first phase shows little deformation until about halfway through the experiment duration when rapid deformation starts to occur. The point of maximum uplift, in both intrusion types, indicates the area of eruption from an early stage. Dataset 2 primarily evaluated the benefits of using the photogrammetric method. It successfully resolved horizontal components of displacement making it possible to study brittle defor- mation. As Dataset 2 consists of a limited amount of experiments, the results cannot be considered conclusive. However, they indicate that characteristic patterns of brittle deformation exist for the two types. Future improvements in this field include studying effects of topography and anisotropy on the surface deformation of the analogue models. Improvements in temporal and spatial resolution in the monitoring methods used to study surface displacement in nature is needed to perform analyses, similar to the ones presented here, on real surface deformation. The misfit of the surface deformation seen in numerical models compared to analogue models indicate that sheet intrusion propagation is not yet fully understood. / När magma rör sig från magmakammare mot jordytan i den ytliga delen av det underjordiska system av magma som finns under vulkaner, bildas ytdeformation. Genom att studera ytdeformationen med hjälp av GPS och InSAR samt numerisk modellering försöker forskare förstå dessa underjordiska processer för att förutspå framtida utbrott. Dessvärre finns ingen möjlighet att undersöka huruvida dessa numeriska modeller faktiskt överensstämmer med naturen. I gamla utdöda vulkaner som eroderats ner kan man se vulkanens inre där det finns stelnade, magmafyllda sprickor, så kallade gångar. Tyvärr ger detta dock ingen inblick i hur gångarnas bildning återspeglades i ytan. Detta kan man undersöka med hjälp av analoga modeller där det är möjligt att skapa likartade intrusioner i en kontrollerad labb-miljö och studera den tillhörande ytdeformationen. Denna avhandling undersöker hypotesen att de två huvudsakliga typerna av ytliga magmatiska gångar skapar specifika identifierbara mönster av ytdeformation. Detta testas genom att dokumentera den analoga modellens yta alltjämt som intrusionerna bildas med hjälp av två olika övervaknings- metoder. Den första metoden lyckades identifiera mönster som är specifika för de två olika typerna. Den högsta punkten på den deformerade ytan kan användas för att förutspå den plats där framtida utbrott kommer att ske i båda typerna. Den andra metoden lyckades urskilja dem horisontella komponenterna av förskjutning som gör det möjligt att studera den spröda deformation som utvecklas på ytan. Resultaten tyder på att karakteristiska mönster av spröd deformation existerar för de två typerna. För att förbättra de analoga modellerna måste man undersöka hur en mer topografiskt varierad yta påverkar den bildade deformation samt en skorpa som inte är helt homogen. Vid jämförelse mellan numeriska modeller och analoga modeller sågs en stor skillnad som tyder på att vi ännu inte förstår hur magma rör sig genom jordskorpan. Framtida användning av analyserna presenterade i denna avhandling kräver en förbättring av upplösningen på systemen som används till vulkanövervakning i naturen.

Les couches de graphene épitaxiées sur la face carbone du carbure de silicium sont tournées les unes par rapport aux autres. Cette rotation préserve la structure de bande linéaire du graphene mono-couche et permet un transport balistique des porteurs de charge. Parmi les propriétés intéressantes développées dans le chapitre 2, la possibilité de former de pleines couches de graphene sur le substrat isolant qu'est le SiC est un avantage majeur de cette technique comparé aux autres méthodes de croissance du graphene (exfoliation et épitaxie en phase vapeur sur métaux). Les grandes surfaces produites permettent aux expérimentateurs de faire facilement des mesures STM car la localisation de la partie utile de l’échantillon n'est pas un problème dans ce cas.Dans ce travail de thèse, j'ai réalisé la croissance de graphene sur la face carbone du SiC dans le but d'étudier la supraconductivité induite dans le graphene par la proximité d'un supraconducteur. Cette supraconductivité induite dont le principe expliqué dans le chapitre 3 se développe d'autant plus loin de l'interface que le matériau non supraconducteur possède un grand libre parcours moyen. D'où notre choix du graphene. Dans le chapitre 3 je présente aussi les efforts que j'ai mené pour fabriquer des jonctions graphene/supraconducteur par une technique de lithographie propre : la lithographie par microsphères. Cette méthode utilise des micro-sphères de silice comme masque dur durant le dépôt par évaporation d'un matériaux supraconducteur tel le vanadium. Malgré la propreté de cette méthode telle qu'avérée par les images STM des échantillons, nous n'avons pas réussi à induire la supraconductivité dans le graphene. Suite à ce résultat négatif, nous avons développé une seconde approche décrite dans le chapitre 4. Un matériau supraconducteur réfractaire, le niobium, est cette fois-ci déposé sur le substrat avant la croissance du graphene. A l'issue de la croissance, nous avons eu la surprise de constater que la température critique du matériaux supraconducteur s'était élevée de 7 à 12 K. Cela s'explique par la carburation du Niobium lors du recuit. Par ailleurs, nous avons bien démontré que des couches graphitiques sont aussi crues sur le NbC permettant ainsi de réaliser des jonctions. Néanmoins, nous n'avons à nouveau pas réussi à observer de supraconductivité induite dans le graphene.Outre les propriétés intéressantes pour l'étude de la supraconductivité induite, les couches de graphene en rotation constituent en elle même un sujet d'étude intéressant. En effet, la densité d'état de ce système présente des singularités de van Hove dont la position en énergie dépend de l'angle de rotation. Ce système ouvre donc la porte à l'étude de la physique associée à ces singularités (supraconductivité, magnétisme) à des énergies accessibles par dopage électrostatique. De plus, une localisation des fonctions d'onde électroniques a été prédite pour les faibles angles de rotation et cette localisation a été confirmée par des résultats expérimentaux préliminaires. Cependant, il manquait une étude systématique des propriétés électriques des systèmes à faible angle de rotation. Les mesures que j'ai réalisé dans ce régime sont présentées dans la dernière partie de ce mémoire. Ces mesures de spectroscopie sont comparées à un modèle de liaison fortes. Le modèle sans désordre et en présence de désordre ne permettent pas de décrire correctement les expériences menées pour des angles inférieurs à 2°. Mon travail souligne qu'une physique riche existe aux faibles angles de rotation et qu'il reste encore beaucoup de travail à faire pour la comprendre. / Epitaxial graphene on carbon-terminated face (C-face) of SiC substrates consists of graphene layers rotated from each other. This rotation of layers grants this material single-layer like properties, such as a linear dispersion band structure and a ballistic transport. As discussed in chapter 2, the full-wafer size and the insulating SiC substrate are two of many advantages of graphene films grown on SiC compared to those prepared differently (exfoliation method and chemical vapour deposition method). These two advantages allow experimentalists to perform scanning tunneling microscopic (STM) experiments and to study graphene properties easily.In this PhD work, we grew graphene on C-face of SiC substrates to investigate the induced superconducting proximity effect in ballistic regime. The physics of this phenomenon is explained in chapter 3 as the formation of time-reversed pairs of electrons and holes. Concerning the superconducting materials, we relied on vanadium and niobium carbide to induce the proximity effect. These two approaches are discussed in detail in chapter 3 (for V) and chapter 4 (for NbC). STM characterizations performed on fabricated samples show a superconducting gap in V and a part of the NbC surface, but no induced gap in graphene. Several possible reasons, like a poor interface between superconductors and graphene, the unability of the STM to reach the true graphene-superconductor interface, and the degradation of the surface of NbC, were suggested and discussed. However, our high-quality epitaxial NbC films meet the requirements for hot-electron bolometers.Besides their single-layer like properties, the rotation of layers also leads to tunable van Hove singularities and the localization of states, which are thoroughly discussed in chapter 5 and 6. Once one of these singularities stays at the Fermi level, graphene is predicted to gain intrinsic superconductivity and magnetic properties. This condition can be achieved by reducing the rotation angle towards zero, as these singularities converge to the Dirac point or the Fermi level for undoped graphene. In addition to the intrinsic superconductivity, the localization of states also appears for layers rotated with a small angle, as observed in several STM experiments. Experimentally, we found regions in rotated layers, which appear as periodic Moiré patterns in our STM images. The rotation angles were estimated from the Fast Fourier Transform of the recorded STM images. Comparing our experimental results with tight-binding calculations for disorder-free layers rotated with the same angles leads to a qualitatively good agreement for the positions of van Hove peaks. However, the appearance of new peaks in proximity to the Dirac point for layers rotated with θ=1.5º and a spatial evolution of of spectroscopic features for the small rotation angles cannot be explained by the calculations for disorder-free layers. In order to explain these two phenomena, we considered the influence of disorder. This indeed improved the agreement between theoretical and experimental results. But, since no electronic disorder could be evidenced from our STM images, other explanations, like strain, need to be considered too.

Orientadores: Inacio Maria Dal Fabbro, Celina de almeida / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-18T14:46:35Z (GMT). No. of bitstreams: 1 Silva_MarcosValerioGebrada_M.pdf: 5359194 bytes, checksum: e831ae3ea9b56a4d77ebb1a53f2352da (MD5) Previous issue date: 2011 / Resumo: A medição de sólidos tridimensionais tem recebido uma grande atenção da comunidade científica, devido à sua ampla gama de aplicações. Como por exemplo, no controle de qualidade industrial, na medição do corpo humano para aplicações de ergonomia, e muitas outras áreas. Porém existem diversos métodos e técnicas para se obter tais medições, este trabalho demonstra a técnica de moiré que é uma técnica sem contato e não destrutiva, com um rápido processo de digitalização cujos fenômenos de Franjas de Moiré são o resultado da subtração da projeção de grades sobre um certo objeto com relação as grades projetadas em um plano referencial. Possui medição precisa comparável com a de outros sistemas. Demonstra também a exatidão das técnicas de moiré, sendo dado maior enfoque na técnica de moiré de projeção com deslocamento de fase, e pela utilização de dois tipos de grades a de Ronchi e senoidal, onde são observados os possíveis erros das diversas técnicas de moiré e por outros métodos metrológicos. Neste trabalho foi comprovado o melhor desempenho dos tipos e variação da frequência de grades incluindo vários exemplos práticos da sua aplicação em sólidos regulares e irregulares (frutos), comparação com outras técnicas em vários problemas em engenharia agrícola e determinação volumétrica de sólidos regulares e irregulares. Emprego de "softwares" gratuitos o qual também foi uma preocupação para disseminação da técnica, tais como ImageJ, RisingSun Moiré, SCILAB/SIP e rotinas / Abstract: Measurement of three-dimensional solids has received great attention from the scientific community due to its wide range of applications. As examples in can be mentioned industrial quality control, human body measurement applied to ergonomics and many other areas. The pertinent literature discloses several methods and techniques to carry three dimensional measurements. Moiré technique is a group of non-contact and non-destructive methods based on the more phenomena which fringes are the result of the subtraction of the grid projected onto the surface under study and the grid projected onto a reference plane. Moiré methods are yield accurate measurements if compared to other measuring systems. This work was foccused on the projection moiré technique with phase shift, and the use of two types of grids named Ronchi and sinusoidal one. Metrological errors of various techniques as compared with the moiré method have been determined as well. This work demonstrated the best performance of grid frequency variation through several practical applied to regular and irregular solids (fruits). Body dimensions were compared with convention techniques as water immersion and calypper. The application of free software such as ImageJ, RisingSun Moire, Scilab / SIP and routines was considered very useful to reach the final results / Mestrado / Maquinas Agricolas / Mestre em Engenharia Agrícola

Dans le cas des matrices polymères à fibres, les efforts sont transférées de la matrice aux renforts par une zone tridimensionnelle appelée interphase. Ses propriétés résultent des interactions physico-chimiques des composants. Deux difficultés SE PRODUISENT : tout d'abord, la nécessité d'étudier l'interphase une fois que le composite est fabriqué et en second lieu, sa taille qui varie d'un nanomètre à quelques micromètres. Cette étude a pour but de mettre au point un protocole de caractérisation des propriétés mécaniques d'une interphase d'un microcomposite. Les champs de déformations, obtenus par dérivation numérique des champs de déplacements expérimentaux, sont traités par une approche inverse, telle que la méthode des champs virtuels, pour permettre l'identification des rigidités du matériau composant l'interphase. Deux techniques expérimentales ont été mises en place pour mesurer le champ de déplacement dans l'interphase pendant un essai de traction : une adaptation du moiré interférométrique (résolution spatiale micrométrique) et la corrélation d'images numériques avec un microscope à grande distance frontale (analyse subpixel). Une comparaison est faite entre ces deux techniques pour cette étude. Le champ des déformations est analysé par la méthode des champs virtuels afin de déterminer les paramètres régissant la loi du comportement de l'interphase.

De nos jours, la radiographie est l'examen de référence pour le suivi des pathologies de la colonne vertébrale. La radiographie bi-planaire permet de plus, par reconstruction 3D, d'évaluer la configuration spatiale de la colonne vertébrale. Cependant, les expositions radiographiques répétées entrainent une augmentation du risque de cancer. Une solution pour réduire les doses de radiation peut être de remplacer certains examens radiographiques par une mesure de la surface du dos. Cette mesure non-invasive permet, entre autre, d'obtenir un grand nombre de paramètres cliniques utiles pour le diagnostic et le suivi des pathologies. Cette mesure permet également d'estimer la configuration du rachis si l'on met en place une modélisation biomécanique adaptée. Le travail réalisé dans cette thèse consiste à développer et mettre en oeuvre une telle modélisation basée sur les informations personnalisées à la fois internes et externes. Le dispositif Biomod 3S (développé par la société AXS Ingénierie, Bordeaux) offre la possibilité d'une acquisition simultanée de radiographies et de surfaces du dos par franges de Moiré. Cette acquisition sur une quinzaine de sujets scoliotiques (des Hôpitaux Universitaires de Bordeaux) a notamment permis d'évaluer les relations entre plusieurs paramètres 3D internes (e.g., la rotation axiale des vertèbres) et de nombreux paramètres 3D externes (e.g., les gibbosités et flèches). Cette acquisition simultanée permet également de prédire la nouvelle configuration de la colonne vertébrale dans une seconde posture où seule la mesure de surface du dos est effectuée. Pour cela, la modélisation en multi-corps rigides articulés qui a été développée (sous Scilab) utilise (a) la géométrie personnalisée de la colonne vertébrale reconstruite dans la première posture et (b) des contraintes issues de la mesure de la surface du dos dans les deux postures (e.g., position de C7). Le modèle a pu être validé sur une dizaine de sujets sains dont la colonne vertébrale et la surface du dos ont été reconstruits en 3D dans différentes positions (debout, penché en avant) à l'aide d'un IRM positionnel. Le modèle a pu également être exploité sur quelques sujets pathologiques. Ce travail, qui a exploré et exploité de nombreuses informations 3D internes et externes, ouvre des perspectives pour le diagnostic et le suivi non-invasif des pathologies de la colonne vertébrale

Orientador: Inacio Maria Dal Fabbro / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T07:26:08Z (GMT). No. of bitstreams: 1 Lino_AntonioCarlosLoureiro_D.pdf: 9389634 bytes, checksum: bc9ff1785fef02812b4b909de86bd347 (MD5) Previous issue date: 2008 / Resumo: A reconstituição do contorno topográfico com geometria simétrica ou assimétrica é uma necessidade fundamental para a ciência e para o desenvolvimento tecnológico. A aplicação do levantamento da topografia dos objetos é refletida em vários campos da ciência como biologia, ortopedia, próteses e órteses humanas, diagnósticos médicos, predição de resultados cirúrgicos, medicina veterinária, controle de qualidade e inspeção industrial, engenharia reversa, modelagem matemática, mecânica dos sólidos, composites, projetos estruturais, elementos de máquinas, robótica e visão de máquina. Este trabalho devota especial atenção a problemas de Engenharia Agrícola tais como definição dos contornos topográficos de animais e produtos vegetais, projetos de elementos de máquinas agrícolas, arquitetura de plantas, interações maquina-solo e maquina-planta, contato pneu-solo, seleção e classificação de produtos agrícolas, determinação de propriedades mecânicas de solo e vegetais, estudos sobre práticas de preparo do solo projetos de embalagens para produtos agrícolas e outros. Entre os métodos perfilométricos mostrados na literatura as técnicas de moiré são consideradas as mais rápidas, de baixo custo, de fácil aplicação e exeqüíveis. A técnica denominada moiré de projeção com deslocamento de fase, devido aos constantes desenvolvimentos, é a que tem aplicabilidade quando comparada às outras técnicas de moiré do gênero. Este trabalho inclui vários exemplos práticos da sua aplicação em vários problemas em Engenharia Agrícola. Determinação da topografia de objetos simétricos, determinação de injurias mecânicas e modelos com coordenadas 3D, são igualmente apresentados. Aplicação de software" tais como ImageJ, Rising Sun Moiré, SCILAB/SIP, Excell e rotinas são apresentadas e igualmente discutidas. As conclusões mostram a exeqüibilidade do método proposto na ciência da Engenharia Agrícola. / Abstract: Shape definition of bodies exhibiting symmetric, non symmetric or irregular geometry is of fundamental necessity for science and technology developments. Applications of objects shape survey is reflected on several science fields as biology, human prosthesis and orthesis, medical diagnosis, prediction of surgical results, orthopedics, veterinary medicine, industrial quality control, reverse engineering, mathematical modeling, solid mechanics, composites, structural design and inspection, machine elements, static and dynamic problems, machine vision and robotics. This research work devotes special attention to agricultural engineering problems as the shape definition of animal as well as vegetable agricultural products, design of farm machinery elements, plant architecture, plant and soil - machine mechanical interactions, soil - tire contact area determination, products selection and sorting, soil and vegetable mechanical properties determination, soil tillage and agricultural practices studies, product packing design and so forth. Amongst the shape survey methods exhibited by the pertinent literature, the moiré methods are here considered feasible, of low cost, of easy application and speedy. Projection moiré with phase shifting technique has been selected to be considered a developed procedure when compared with remaining moiré methods, presenting also recent developments. This research work includes a variety of practical examples on several agricultural engineering subjects. Shape determination of symmetric bodies, determination of mechanical injuries proportions on agricultural products and three dimensional coordinates model are presented as well. Employed softwares included ImageJ, RisingSun Moiré, SCILAB/SIP, Excell and routines. The conclusions refer to the feasibility of the proposed method to the agricultural engineering science. / Doutorado / Maquinas Agricolas / Doutor em Engenharia Agrícola

The characterization of the material’s deformation is nowadays common in transmission electron microscopy. The ability to resolve the crystalline lattice enables the strain to be linked with the deformation of the crystal unit cells. Imaging the crystal unit cells imposes the sampling scheme to oversample the resolved crystal periodicities and, thus, limits the field of view (FOV) of the micrograph. Therefore, alternative methods were developed (electron diffraction and holography) to overcome the FOV limitation. The method presented in this thesis is part of the large FOV challenge. Its principle is based on the coherent interference of the sampling grid with the crystalline lattices of the material in scanning transmission electron microscopy (STEM). The interference results to a set of Moiré fringes embedding the structural properties of the material such as a strain field. The STEM Moiré hologram (SMH) formation can be elegantly described using the concept of Moiré sampling in STEM imaging. The STEM Moiré fringes reveals to be undersampling artefacts commonly known as aliasing artefacts. The SMH is, therefore, violating the sampling theorem and is not a proper representation of the crystal unit cells. However, an oversampled representation can be recovered from the SMH using a set of prior knowledge. The SMH becomes suitable to characterize the 2D strain field giving birth to a new dedicated method, called STEM Moiré GPA (SMG), that is using the Geometric Phase Analysis method on the SMH directly. After detailing the theory of SMG, the technique is validated experimentally by comparing it to other strain characterization methods and to Finite Element Method simulations. The characteristics of SMG (resolution, precision and accuracy) and its limits are then detailed. Finally, the SMG method is applied on semiconductor devices to highlight the typical capabilities of the technique. / Thesis / Doctor of Philosophy (PhD)