Materiais compostos de matriz metálica (CMM) vêm sendo estudados para diversas aplicações. Entretanto, pouco estudo é apresentado na sua confecção a partir de materiais reciclados. Este trabalho teve como objetivo a caracterização de um material composto de matriz metálica (CMM), utilizando material reciclado como matéria prima. Foram usados aparas de chapas de liga de alumínio 2024 descartados para a matriz e carbeto de silício (SiC) como reforço, sendo a produção realizada através do processo de fabricação com base na técnica de conformação por spray para possível aplicação em componentes automotivos. Foi realizado o tratamento térmico do material e a caracterização, determinando as propriedades de dureza, resistência mecânica, resistência ao desgaste, MEV e EDS. Foram ensaiadas amostras do material composto fundido e extrudado, bem como de ferro fundido de uma peça automotiva e da liga de alumínio 2024. Observou-se que o CMM ainda precisa de melhorias no processo de produção para obter propriedades de dureza e resistência que permitam que ele possa ser usado como um substituto para o ferro fundido, porém o mesmo apresentou melhores propriedades quando comparado com o material da matriz. / Metal matrix composites (MMC) have been studied for several applications. However, little study is presented in its manufacture from recycled materials. This study aimed to characterize a metal matrix composite (MMC), using recycled material as raw material. Were used aluminum alloy 2024 plates clippings discarded for the matrix and silicon carbide (SiC) as reinforcement, being the production accomplished through the manufacturing process based on the technique of spray forming for possible application in automotive components. The thermal treatment and the characterization of the materia was accomplished, determining the properties of hardness, mechanical strength, wear resistance, SEM and EDS. Were tested samples of the cast and extruded composite material, as well as cast iron of an automotive part and aluminum alloy 2024. It was observed that the MMC still needs improvements in the production process to obtain properties of hardness and strength that allows it to be used as a substitute forcast iron, but it presented better properties when compared with the matrix material.

L'objectif de cette thèse est d'élaborer un système de reconnaissance de mots manuscrits pouvant être appris et appliqué sur différents styles d'écriture. L'approche utilisée est une approche analytique: les mots sont découpés en sous-parties (caractères) à modéliser. Le découpage est effectué de manière implicite par l'utilisation de fenêtres glissantes qui permettent de transformer les images de mots en séquences. La méthode choisie pour apprendre les modèles de caractères utilise les modèles de Markov cachés (HMMs). Chaque caractère est représenté par un HMM de type Bakis, ce qui permet d'absorber les variations d'écriture entre scripteurs. Les mots sont reconstruits ensuite par concaténation des modèles qui les composent. Dans cette thèse, le choix est fait de chercher à améliorer la modélisation HMM de caractères en agissant au coeur même des modèles. A cette fin, une nouvelle approche est proposée, qui utilise l'aspect contextuel pour la modélisation : un caractère est modélisé en fonction de son contexte et son modèle est nommé trigraphe. La prise en compte de l'environnement d'un caractère pour sa modélisation implique cependant une multiplication des paramètres HMMs à apprendre sur un nombre souvent restreint de données d'observation. Une méthode originale de regroupement de paramètres est proposée dans ces travaux : le clustering d'états par position à l'aide d'arbres binaires de décision. Ce type de clustering, inédit dans les systèmes de reconnaissance de l'écriture, permet au système de réduire le nombre de paramètres tout en conservant l'un des principaux attraits des HMMs : l'utilisation d'un lexique de test indépendant de celui d'apprentissage.

Recent Advancements in Solid State Memories have resulted in packing several Giga Bytes (GB) of memory into tiny postage stamp size Memory Cards. Of late, Secure Digital (SD) cards have become a de-facto standard for all portable handheld devices. They have found growing presence in almost all embedded applications, where huge volumes of data need to be handled and stored. For the very same reason SD cards are being widely used in space applications also. Using these SD Cards in space applications requires robust radiation hardened SD cards and Highly Reliable Fault Tolerant File Systems to handle them. The present work is focused on developing a Highly Reliable Fault Tolerant SD card based FAT16 File System for space applications.

In this thesis, a high precision motion and position control system has been developed and applied to a high voltage sphere gap control and measurement system. The system is able to support up to 3-axes position and motion control. The control system includes a microcontroller card, three DC servo motor driver cards and a data storage unit. To provide communication between computer and motion control system, the Universal Serial Bus (USB) port is used. The microcontroller card is equipped with an USB interface and a PIC (Peripheral Interface Controllers) microcontroller. This microcontroller controls the dedicated motion control processors (LM629), on servo motor driver cards and read/write operations of data storage unit, which consists of a Multi Media Card.

Materiais compósitos são projetados e fabricados para várias aplicações de alto desempenho, incluindo componentes para os segmentos automobilístico, aeroespacial, aeronáutico, naval, de defesa, de óleo e gás, energia eólica e até equipamentos esportivos. Porém, a união por soldagem de Compósitos de Matriz Metálica de Alumínio (Al-CMM) ainda é um grande obstáculo para a maior disseminação desta classe de materiais estruturais. As mudanças microestruturais decorrentes do ciclo de soldagem e/ou do tratamento térmico afetam sensivelmente as propriedades mecânicas e físico-químicas finais da junta e do metal base nas proximidades de mesma, daí a importância de se estudar a evolução microestrutural que prospera nestas etapas. O presente trabalho caracterizou a microestrutura do compósito liga-A356/SiCp soldado por laser de fibra de Itérbio, empregando-se nessa tarefa técnicas de microscopia óptica, radiografia e microscopia eletrônica de varredura, assim como difração de raios-X e de elétrons retroespalhados, ensaio instrumentado de dureza e microtomografia computadorizada. O foco das análises realizadas restringiu-se à geometria dos cordões de solda, à expulsão de SiC particulado da zona soldada, à volatilização de elementos químicos da poça de soldagem, à formação de precipitados fragilizantes de Al4SiC4 em formato de agulhas no cordão de solda e à determinação das regiões com concentração de poros, todos estes fenômenos tendo efeitos nocivos, em maior ou menor extensão, no desempenho global da junta do Al-CMM soldada a laser, notadamente em suas propriedades mecânicas e eletroquímicas. / Microstructural materials composites are designed and manufactured for various high performance applications, including components for different industries like automobile, aerospace, aeronautical, naval, defense, oil and gas, wind energy and even sports equipment. However, the junction by welding of Aluminum Metal Matrix Composite (Al-MMC) is still a major obstacle to the further spread of this class of structural materials. The microstructural changes resulting from the welding cycle and / or post-weld heat treatment significantly affect the final mechanical and physicochemical properties of the joint and the base metal near it, hence the importance of studying the microstructural evolution that thrives in these steps. This study aims to characterize the microstructure of the composite alloy-A356 / SiCp welding by Ytterbium fiber laser, using optical microscopy, X-ray, scanning electron microscopy, X-ray diffraction, electron backscatter diffraction, instrumented test hardness and computed microtomography. The focus of the analyzes was restricted to the geometry of the weld bead, the particulate SiC expulsion of the welded zone, volatilization of chemical elements from the welding zone, formation of precipitates embrittlement of Al4SiC4 in needle shape in the weld bead and determining the concentration of regions with pores, all these phenomena have harmful effects to a greater or lesser extent, the overall performance of the joining Al-CMM laser welded, mainly in their mechanical and electrochemical properties.

Materiais compostos de matriz metálica (CMM) vêm sendo estudados para diversas aplicações. Entretanto, pouco estudo é apresentado na sua confecção a partir de materiais reciclados. Este trabalho teve como objetivo a caracterização de um material composto de matriz metálica (CMM), utilizando material reciclado como matéria prima. Foram usados aparas de chapas de liga de alumínio 2024 descartados para a matriz e carbeto de silício (SiC) como reforço, sendo a produção realizada através do processo de fabricação com base na técnica de conformação por spray para possível aplicação em componentes automotivos. Foi realizado o tratamento térmico do material e a caracterização, determinando as propriedades de dureza, resistência mecânica, resistência ao desgaste, MEV e EDS. Foram ensaiadas amostras do material composto fundido e extrudado, bem como de ferro fundido de uma peça automotiva e da liga de alumínio 2024. Observou-se que o CMM ainda precisa de melhorias no processo de produção para obter propriedades de dureza e resistência que permitam que ele possa ser usado como um substituto para o ferro fundido, porém o mesmo apresentou melhores propriedades quando comparado com o material da matriz. / Metal matrix composites (MMC) have been studied for several applications. However, little study is presented in its manufacture from recycled materials. This study aimed to characterize a metal matrix composite (MMC), using recycled material as raw material. Were used aluminum alloy 2024 plates clippings discarded for the matrix and silicon carbide (SiC) as reinforcement, being the production accomplished through the manufacturing process based on the technique of spray forming for possible application in automotive components. The thermal treatment and the characterization of the materia was accomplished, determining the properties of hardness, mechanical strength, wear resistance, SEM and EDS. Were tested samples of the cast and extruded composite material, as well as cast iron of an automotive part and aluminum alloy 2024. It was observed that the MMC still needs improvements in the production process to obtain properties of hardness and strength that allows it to be used as a substitute forcast iron, but it presented better properties when compared with the matrix material.

L’imagerie par résonance magnétique fonctionnelle (IRMf) est un outil de choix pour cartographier d’une manière non invasive l’activité du cortex, donnant ainsi un accès à l’organisation fonctionnelle cérébrale. Cette organisation des aires cérébrales en réseaux complexes reste encore un vaste sujet d’étude, autant dans le domaine de la recherche fondamentale, pour mieux comprendre le développement et le fonctionnement du cerveau, que dans le domaine clinique, à des fins diagnostiques par exemple. Les réseaux cérébraux dits de repos, chez un sujet donné, peuvent être observés lors d’études IRMf lorsqu’aucune tâche motrice ou cognitive n’est imposée au sujet imagé. La première partie de cette thèse a permis le développement d’une méthode automatique d’identification de ces réseaux. Réalisée à l’échelle du sujet, cette méthode permet de sélectionner tous les réseaux spécifiques au sujet ce qui s’avère nécessaire dans un cadre diagnostique où l’individu prime. Au delà de la détection et de l’identification de ces réseaux, l’étude de leurs modes d’interaction dans l’espace et dans le temps et plus généralement l’analyse de la dynamique de la connectivité fonctionnelle (DCF) fait l’objet d’un intérêt grandissant. Cette analyse nécessite le développement de méthodes innovantes de traitement du signal et de l’image qui, pour l’heure, sont encore de nature exploratoire. La deuxième partie de cette thèse présente donc de nouvelles approches pour caractériser la DCF en utilisant le cadre probabiliste de modèles de Markov cachés multidimensionnels. Les mécanismes conversationnels entre réseaux cérébraux peuvent ainsi être identifiés et caractérisés à l’échelle de la seconde. Deux applications, au niveau du sujet puis du groupe, ont permis de mettre en avant les modifications des propriétés dynamiques des interactions entre réseaux sous certaines conditions ou pathologies. / The functional magnetic resonance imaging (fMRI) is a perfect tool for mapping in a non- invasive manner the activity of the cortex, giving access to the functional organization of the brain. This organization of brain areas into complex networks remains a large topic of study, both from a fundamental research perspective, to better understand the development and function of the brain, and from a clinical perspective, for diagnostic purposes for instance. The resting-state networks in a given subject can be observed in fMRI studies where no motor or cognitive tasks are imposed to the subject. The first part of this thesis focused on the development of an automatic identification method of these networks. Performed at the subject level, this method selects all the resting-state networks proper to the subject. Beyond the detection and identification of these networks, the study of interactions between these networks in space and time, and more generally the analysis of the dynamic functional connectivity (DFC), is the subject of growing interest. This analysis requires the development of innovative methods of signal or image processing that, for now, are still exploratory. The second part of this thesis thus presents new approaches to characterize the DFC using the probabilistic framework of multidimensional hidden Markov models. Conversational mechanisms between brain networks can be identified and characterized at the resolution of the second. Two applications, first on a single subject then on a group, helped to highlight the changes of dynamic properties of interaction between networks under certain conditions or diseases.

Throughout the ages makeup has been used to hide blemishes, blur imperfections and provide an oil free look of the skin. In the past few years, more attention has been given to face powders ingredients as some of them may be associated with health risks as well as impact the environment. Therefore, there is a need for new safe cosmetic ingredients with improved performance.  It has previously been shown that Upsalite®, a mesoporous magnesium carbonate with an extraordinary high surface area and narrow pore size distribution, has great potential to replace other powder ingredients used as fillers and absorbers in powder cosmetics. In this work functional and physical attributes of Upsalite in powder cosmetics have been further investigated to generate comparative data for claim support. Oil uptake, speed and interaction were investigated and compared with other powders. In addition, a method to quantify transparency and blurring effect of Upsalite compared to other materials has been developed and applied.  It was shown that Upsalite has exceptional absorption capacity of oil and is able to absorb oil much quicker than silica and other cosmetic powders. Preferential interaction with polar compared to non-polar oils was found and the dual interaction of Upsalite with oil and moisture was further substantiated. Transparency studies of Upsalite revealed that Upsalite is more transparent on a glass substrate but was found opaquer on skin than talc and mica. This is explained by that its measured refractive index of 1.62 is slightly higher leading to a somewhat improved coverage. The blurring effect study showed that Upsalite has a blurring index in the range of the best existing cosmetic powders, improving blurring index of mica, talc and BN-12 by up to 60% and can replace silica and microplastics such as Nylon-12. Upsalite was found to visually blur imperfections without looking white.

The dissertation thesis deals with the determination of uncertainty of strain measurement and the stress using resistance strain gages. You can find two methods to define the uncertainty in the thesis, GUF and MMC, and both are applied for measurements carried out with resistance strain gages. Definition of the measurement uncertainty was set for the strain measured by uniaxial and biaxial strain gages. The uncertainty of the stress was defined for linear strain gages, T Rosettes and Rosettes. There were universal mathematic-technical models defined to measure strain and stress, these models can be used either for standard and special measurements i.e. high-temperature, or for measurements in radiation field. Each part of the strain uncertainty and stress is analyzed from the point of view of a size of uncertainty and a form of probability of the function that strain and stress can adopt. The maximum focus was dedicated to the mistakes influencing measured strain like strain gage properties, installation and operating influences, external influences, time effects and the influence of the measured object. There are two mistakes influencing the stress described and analyzed in the thesis, the mistake of the Young’s modulus of elasticity and the mistake of the Poisson’s ratio. The thesis is conceived as a complex of information related to the measurement uncertainties using the resistance strain gages and methods of defining the measurement uncertainty in a way that the experimenter can apply the gained info and methods in the required measurements. The final chapters give representative examples to define measurement uncertainties for uniaxial and biaxial stress applying GUF and MMC method. The thesis also includes the experiment that compares measured values of strain, stress and measurement uncertainties, using several different types of strain gages at different temperatures, with theoretical calculation of strain and with stress. The experiment was carried out using the displacement sensor that works on an elementary principle of bending load.

This thesis deals with a design of speedometer for sportsmen, which is able to display current speed and to record a trip. The proposed parts are small enough. That's why sportsman won't be bothered much. The GPS is used for measurement of speed and to determine position. A strip, which consists of LED diodes, is used for speed displaying. The strip is situated in a sportsman's glasses. A trip is recorded to a MultiMediaCard. The FAT file system is used on the memory card.