A texturização por microusinagem a laser é uma importante alternativa para que se consiga melhorar a ligação de aderência entre materiais compósitos e o titânio, aplicados em componentes estruturais na indústria aeronáutica. A execução de texturização em chapas de titânio deve-se ao fato de que a técnica de junção preferida para muitos materiais compósitos é a ligação adesiva. Neste trabalho foram realizadas texturizações em chapas de titânio utilizando laser com pulsos ultracurtos de largura temporal da ordem de femtossegundos. Tal processo resultou em mínima transferência de calor para o material, evitando assim deformação superficial da chapa de titânio bem como a formação de material ressolidificado na região ablacionada. Estes inconvenientes ocorreram na utilização do laser chaveado com pulsos de nanossegundos. Foram executadas três tipos de texturizações utilizando laser com pulsos de femtossegundos, com variações nas distâncias entre as linhas usinadas. Pela análise das superfícies obtidas, detectou-se que a molhabilidade aumenta quando há o aumento da distância entre as linhas da texturização. Avançando nas análises, pela perfilometria óptica das superfícies texturizadas observou-se que há sensível aumento do volume disponível para penetração do adesivo estrutural quando são diminuídas as distâncias entre as linhas texturizadas. Nos ensaios de tração realizados observou-se que há o aumento da resistência ao cisalhamento da junta adesiva com a diminuição da distância entre as linhas texturizadas. / The texturing laser micromachining is an important alternative to improve the bonding adhesion between composites and titanium, which are applied to structural components in the aerospace industry. The texturing running on titanium plates is due to the fact that the preferred joining technique for many composite materials is the adhesive bonding. In this work, titanium plates were texturized using laser ultrashort pulses temporal widths of femtoseconds. This process resulted in minimal heat transfer to the material, avoiding deformation of the titanium plate surface as well as the formation of resolidified material in the ablated region. These drawbacks have occurred with the use of nanoseconds pulses. Were performed three types of texturing using laser with femtosecond pulses, with variations in the distances between the machined lines. The analysis of the obtained surfaces found that the wettability increases when there is the increased distance between the texturing lines. Advancing in the analysis by optical profilometry of textured surfaces was observed that there is substantial increase in the volume available for penetration of structural adhesive when the distances between the textured lines are diminished. In tensile tests conducted it was observed that there is an increase in shear strength of the adhesive joint by reducing the distance between the textured lines.

A texturização por microusinagem a laser é uma importante alternativa para que se consiga melhorar a ligação de aderência entre materiais compósitos e o titânio, aplicados em componentes estruturais na indústria aeronáutica. A execução de texturização em chapas de titânio deve-se ao fato de que a técnica de junção preferida para muitos materiais compósitos é a ligação adesiva. Neste trabalho foram realizadas texturizações em chapas de titânio utilizando laser com pulsos ultracurtos de largura temporal da ordem de femtossegundos. Tal processo resultou em mínima transferência de calor para o material, evitando assim deformação superficial da chapa de titânio bem como a formação de material ressolidificado na região ablacionada. Estes inconvenientes ocorreram na utilização do laser chaveado com pulsos de nanossegundos. Foram executadas três tipos de texturizações utilizando laser com pulsos de femtossegundos, com variações nas distâncias entre as linhas usinadas. Pela análise das superfícies obtidas, detectou-se que a molhabilidade aumenta quando há o aumento da distância entre as linhas da texturização. Avançando nas análises, pela perfilometria óptica das superfícies texturizadas observou-se que há sensível aumento do volume disponível para penetração do adesivo estrutural quando são diminuídas as distâncias entre as linhas texturizadas. Nos ensaios de tração realizados observou-se que há o aumento da resistência ao cisalhamento da junta adesiva com a diminuição da distância entre as linhas texturizadas. / The texturing laser micromachining is an important alternative to improve the bonding adhesion between composites and titanium, which are applied to structural components in the aerospace industry. The texturing running on titanium plates is due to the fact that the preferred joining technique for many composite materials is the adhesive bonding. In this work, titanium plates were texturized using laser ultrashort pulses temporal widths of femtoseconds. This process resulted in minimal heat transfer to the material, avoiding deformation of the titanium plate surface as well as the formation of resolidified material in the ablated region. These drawbacks have occurred with the use of nanoseconds pulses. Were performed three types of texturing using laser with femtosecond pulses, with variations in the distances between the machined lines. The analysis of the obtained surfaces found that the wettability increases when there is the increased distance between the texturing lines. Advancing in the analysis by optical profilometry of textured surfaces was observed that there is substantial increase in the volume available for penetration of structural adhesive when the distances between the textured lines are diminished. In tensile tests conducted it was observed that there is an increase in shear strength of the adhesive joint by reducing the distance between the textured lines.

<p>Implement a high-level model of computationally intensive part of 3D graphics pipe-line. Increasing popularity of handheld devices along with developments in hardware technology, 3D graphics on mobile devices is fast becoming a reality. Graphics processing is essentially complex and computationally demanding. In order to achieve scene realism and perception of motion, identifying and accelerating bottle necks is crucial. This thesis is about Open-GL graphics pipe-line in general. Software which implements computationally intensive part of graphics pipe-line is built. In essence a rasterization unit that gets triangles with 2D screen, texture co-ordinates and color. Triangles go through scan conversion, texturing and a set of other per-fragment operations before getting displayed on screen.</p>

Photovoltaic (PV) cells with a three dimensional (3D) morphology are an exciting new research thrust with promise to create cheaper, more efficient solar cells by allowing for a "bottom up" approach to texturing thin film solar cells. This work introduces a new type of 3D PV device based on carbon nanotube (CNT) arrays. These arrays are paired with the thin film heterojunction, CdTe/CdS, to form a complete 3D carbon nanotube PV device (3DCNTPV). A complete theory for the power increase at off-normal angles of solar flux is developed for these cells. Marriage of a complicated 3D structure with production methods traditionally used for planar CdTe solar cell is challenging. This work examines the problems associated with processing these types of cells and systematically alters production methods of the semiconductor layers and electrodes to increase the short circuit current, eliminate parasitic shunts, and increase the open circuit voltage.

The use of fractal-based methods in imaging was first popularized with fractal image compression in the early 1990s. In this application, one seeks to approximate a given target image by the fixed point of a contractive operator called the fractal transform. Typically, one uses Local Iterated Function Systems with Grey-Level Maps (LIFSM), where the involved functions map a parent (domain) block in an image to a smaller child (range) block and the grey-level maps adjust the shading of the shrunken block. The fractal transform is defined by the collection of optimal parent-child pairings and parameters defining the grey-level maps. Iteration of the fractal transform on any initial image produces an approximation of the fixed point and, hence, an approximation of the target image. Since the parameters defining the LIFSM take less space to store than the target image does, image compression is achieved.This thesis extends the theoretical and practical frameworks of fractal imaging to one involving a particular type of multifunction that captures the idea that there are typically many near-optimal parent-child pairings. Using this extended machinery, we treat three application areas. After discussing established edge detection methods, we present a fractal-based approach to edge detection with results that compare favourably to the Sobel edge detector. Next, we discuss two methods of information hiding: first, we explore compositions of fractal transforms and cycles of images and apply these concepts to image-hiding; second, we propose and demonstrate an algorithm that allows us to securely embed with redundancy a binary string within an image. Finally, we discuss some theory of certain random fractal transforms with potential applications to texturing. / The Natural Sciences and Engineering Research Council and the University of Guelph helped to provide financial support for this research.

The rising cost in video game content creation, both in terms of man hours and in terms of monetary dollars, restricts the ability of video game developers to create unique, entertaining content. Motivated by how this cost is a direct result of "next-generation graphics", I am motivated to ask: what would a next-generation content creation tool look like? I investigate the problem by constructing several such tools. In particular, I construct a mesh quilting algorithm for random level generation, a rapid level construction toolkit based on the concept of an architectural blueprint but supporting features such as complex silhouette geometry and roof geometry, and a tool for rapidly painting world textures. I also introduce a new system for accessing barycentric coordinate data from within the fragment shader, which can be used in support of real-time 3D image quilting, more accurate normal interpolation, and texture rendering from within the world painting tool. Some history of video game content creation is discussed, and a roadmap is charted for future development. / Graduate

My thesis involves studying the nature of chimera through history and how certain aspects of chimeras represent specific features of dualities in human nature. The research was reflected in a series of sketches, where one sketch was finalized into a fully realized 3D model. To aid in this goal, I created a system that will randomly generate chimera based on different characteristics. This system was created using Max 5, and was programmed to place images with alphas on top of each other to create unique chimeras. The variables within this system are derived from the research on chimeras depicted in art and mythology throughout history, and will be used as an inspirational tool to help generate unique combinations of chimeras that may not otherwise have been imagined.

Dans cette thèse, nous présentons un système complet permettant de sauvegarder un processus destructif tel qu'une dissection anatomique. Nous proposons une méthode depuis l'acquisition 3D des données jusqu'à la visualisation interactive et immersive, dans le but de créer une vérité terrain. L'acquisition 3D regroupe l'acquisition de la géométrie par scanner laser (maillage) ainsi que de l'information de couleur par le biais d'un appareil photo haute résolution (texture). Ce processus d'acquisition et répété au cours de la dissection du spécimen. Les différentes acquisitions du spécimen sont représentées par des surfaces 3D texturées. Elles sont ensuite recalées entre elles. Un expert anatomiste peut alors explorer ces différentes étapes de dissections modélisées dans une visualisation immersive en utilisant du matériel d'interaction (bras haptique). Un outil d'étiquetage permet une segmentation manuelle précise de régions d'intérêt visibles sur chacune des surfaces 3D. Un objet tridimensionnel peut ensuite être reconstruit et proposé à l'utilisateur sur la base des zones d'intérêt étiquetées. Le but étant de créer des vérité terrains afin de confronter des résultats issus de modalités d'acquisition volumiques (IRM). Nous montrons l'application de la méthode à la reconstruction de faisceaux de fibres blanches humaine dans le but de valider des résultats de tractographie. / In this thesis, we present a system to keep track of a destructive process such as a medical specimen dissection, from data acquisition to interactive and immersive visualization, in order to build ground truth models. Acquisition is a two-step process, first involving a 3D laser scanner to get a 3D surface, and then a high resolution camera for capturing the texture. This acquisition process is repeated at each step of the dissection, depending on the expected accuracy and the specific objects to be studied. Thanks to fiducial markers, surfaces are registered on each others. Experts can then explore data using interaction hardware in an immersive 3D visualization. An interactive labeling tool is provided to the anatomist, in order to identify regions of interest on each acquired surface. 3D objects can then be reconstructed according to the selected surfaces. We aim to produce ground truths which for instance can be used to validate data acquired with MRI. The system is applied to the specific case of white fibers reconstruction in the human brain.

Le polyéthylène à ultra-haut poids moléculaire (PE-UHPM) est un matériau utilisé comme composant d’appui dans les prothèses articulaires, dont la durabilité dépend des propriétés chimiques et mécaniques de ce polymère. Une des principales étapes de la production de composants en PE-UHPM pour les prothèses est la réticulation par irradiation qui améliore considérablement la résistance à l'usure, mais dans le même temps, réduit drastiquement la stabilité chimique, la résistance à la traction et la résistance à la fracture du PE-UHPM. La texturation, définit comme un procédé induisant la formation d'un réseau de molécules alignées,pourrait être un traitement alternatif à la réticulation, car elle peut augmenter la résistance à la traction et la résistance à la fracture d'un polymère sans altérer ses propriétés chimiques. Cependant,peu d'informations sont connues sur l'effet de l'orientation initiale des chaînes sur le glissement et le comportement à l’usure du PE-UHPM texturé. Dans cette thèse, l'effet de l'état d'orientation des chaînes sur le comportement au glissement et à l'usure du PE-UHPM est étudié, ainsi que les mécanismes sous-jacents. / Ultra-high molecular weight polyethylene (UHMWPE) is a material widely used as bearing material in joint prostheses whose durability depends on its chemical and mechanical properties. One of the main steps in the production of UHMWPE parts for prostheses is an irradiation-induced cross-linking that considerably improves wear resistance, but at the same time lowers drastically the chemical stability, tensile strength, and toughness of UHMWPE.Texturing like e.g. the formation of a stretched molecular network, could be an alternative treatmentto cross-linking, since it can increase strength and toughness of a polymer without altering itschemical properties. However, little information is yet available about the effect of chain orientationon the sliding and wear behaviour of textured UHMWPE. In this PhD thesis, the effect of the chainorientation state on the sliding and wear behaviour of UHMWPE is investigated as well as the underlying mechanisms.

A propriedade volume do fio texturizado é importante por questões estéticas e funcionais. O volume do fio pode garantir que um produto tenha bom desempenho mecânico tanto na produção dos artigos (como na tecelagem, malharia e acabamento) quanto para as aplicações finais dos produtos (produtos com alto fator de cobertura, com elasticidade, isolamento térmico etc.). A texturização por falsa torção fixada é um importante processo industrial que possui dentre os principais objetivos o aumento de volume. A etapa de fixação consiste em um tratamento térmico do fio ao final do processo, por meio da passagem do fio texturizado em um forno, conhecido como forno de fixação ou segundo forno. No presente estudo foi analisada a interação entre as variáveis temperatura do forno de fixação e sobrealimentação do fio dentro do forno de fixação. A propriedade volume dos fios texturizados é comumente tratada nas literaturas como encrespamento, termo que será utilizado no presente trabalho. Para a análise do volume do fio definiu-se três propriedades mecânicas: contração do encrespamento, módulo do encrespamento e estabilidade do encrespamento. Com a utilização da ferramenta estatística planejamento do desenvolvimento definiu-se que o estudo seria realizado com dois fatores (temperatura do forno e sobre alimentação do fio); dois diferentes níveis (mínimo e máximo para cada fator) e um ponto central. Para cada proposta de teste foram feitas 10 replicações e 50 ensaios foram realizados. Com as amostras dos fios texturizados foram realizados os ensaios para a determinação das propriedades: contração, módulo e estabilidade do encrespamento; com o equipamento Texturmat da Textechno. Com os dados, realizou-se a análise fatorial para a determinação da importância deles e a regressão linear, para a compreensão do comportamento desses dados em função dos ensaios realizados. As análises possibilitaram observar que a etapa de fixação é muito importante nas propriedades de volume do fio, sendo que a sobrealimentação do fio dentro do forno de fiação apresentou-se como a variável mais relevante para a definição desse parâmetro. / Crimp properties are important by functional and aesthetics issues. The crimp of a yarn can provide a good mechanical performance in the production (weaving, knitting and finishing) and also a good result in the final application (products with high covering factor, elasticity, thermal insulation etc). The False Twist texturing is an important industrial process that has the objective of apply bulk on the yarn. The heat setting stage consists of a thermal treatment on the yarn at the end of the process, by the passage of yarn thru a heater that is known as heat setting heater or second heater only. At this paper was analyzed the interaction between second heater temperature and yarn overfeed inside second heater. For crimp analysis were considered three mechanical properties: crimp contraction, crimp module and crimp stability. Using the statistical tool, Design of Experiments, it was defined that would be used two factors (second heater temperature and yarn overfeed inside second heater); two different levels (minimum and maximum for each factor) and a center point. For each test proposal were realized 10 replications, resulting on 50 trials. With Texturmat, from Textechno, tests were realized on the samples (textured yarn) to verify the crimp properties (contraction, modulus and stability). A factor analysis was realized with data from Texturmat to verify the importance of each factor. A linear regression for each property was calculated to better understand the data in terms of the tests. In general it was possible to see the importance of heating set stage on crimp properties of textured yarns and the yarn overfeed inside second heater is the most important variable to define this parameter.