Avec une croissance considérable dans le domaine de la technologie multimédia et de la forte disponibilité des logiciels de traitement d'image, il est désormais facile de manipuler les images numériques. En même temps, il est devenu possible de réaliser des contrefaçons très élaborées, en laissant très peu de traces. Cela présente un grave problème, en particulier, si l'authenticité de l'image numérique est exigée. L'authentification des images devrait se baser sur leurs contenus visuels et non pas sur leurs contenus binaires. Par conséquent, pour authentifier une image, il faut tolérer quelques manipulations acceptables que pourrait subir une image telles que la compression JPEG et l'ajout de bruit Gaussien. En effet, ces manipulations préservent l'aspect visuel de l'image. En même temps un système de hachage perceptuel doit être suffisamment fragile pour détecter les manipulations malveillantes qui modifient l'interprétation du contenu sémantique de l'image comme l'ajout de nouveaux objets, la suppression ou la modification majeure d'objets existants.Dans cette thèse, nous nous intéressons aux fonctions de hachage perceptuel pour l'authentification et le contrôle d'intégrité des images numériques. Dans ce but, nous présentons tous les aspects relatifs aux fonctions de hachage perceptuel. Puis, nous exposons les contraintes qu'un système de hachage perceptuel doit satisfaire pour répondre aux exigences souhaitées au niveau de la robustesse des signatures perceptuelles. Enfin, nous présentons une méthode permettant d'améliorer la robustesse et la sécurité d'un système dehachage perceptuel. / The widespread use of multimedia technology has made it relatively easy to manipulate and tamper visual data. In particular, digital image processing and image manipulation tools offer facilities to intentionally alter image content without leaving perceptual traces. This presents a serious problem, particularly if the authenticity of the digital image is required. The image authentication should be based on their visual content and not on their binary content. Therefore, to authenticate an image, some acceptable manipulations that could undergoes an image, such as JPEG compression and Gaussian noise addition, must tolerated. Indeed, these manipulations preserve the visual appearance of the image. At the same time a perceptual hashing system should be sufficiently sensitive to detect malicious manipulations that modify the interpretation of the semantic content of the imagesuch as adding new objects, deleting or major modification of existing objects.In this thesis, we focus on perceptual hash functions for authentication and integrityverification of digital images. For this purpose, we present all aspects of perceptual hashfunctions. Then, we discuss the constraints that perceptual hashing system must satisfy tomeet desired level of robustness of perceptual signatures. Finally, we present a method toimprove the robustness and security of a system of perceptual hashing.

La miniaturisation des circuits intégrés permet d'avoir une intégration plus élevée dans une même puce. Cela, conduit a des problèmes de qualité dans les signaux de communication et d’alimentation comme le phénomène de bruit de diaphonie entre les interconnections (Crosstalk) et de bruit dans le lignes d'alimentation (PSN, GB). Aussi problèmes de fiabilité peuvent éventuellement arriver a cause des variations dans les paramètres technologiques pendant le processus de fabrication. De ce fait, tout ces phénomènes ont un effet négatif sur le délai dans les circuits embarques (IC) et donnent lieu aux défauts sur le retard. Des échecs relie au délai dans les dispositifs semi conducteurs causes une augmentation de taux d'évasion de défaut, une perte de rendement et une diminution dans le taux de fiabilité. Techniques de Design-For-Test ont était développée a fin d'avoir une meilleur contrôlabilité et observabilité dans les nœuds internes du circuit pour détecter et localiser facilement l’emplacement des défauts. Cependant, ils ne sont pas toujours détectés par les modèles de défauts traditionnels.Cette thèse s’intéresse a l’analyse de ces phénomènes a fin de proposer de nouvelle méthodes de test du délai en considérant les phénomènes physiques pour faire face aux défauts provenant du processus de fabrication ou de problèmes physiques. Ces méthodes comprennent l'analyse de la variation du retard d'un chemin en présence du bruit de diaphonie, du bruit d'alimentation, et les variations de processus. Additionnellement, nous développons méthodes d'essai de retard sur un chemin pour identifier les motifs de test qui peuvent causer le pire des cas de retard sur un chemin cible. Les méthodes proposées peuvent être utilisées pour caractériser la vitesse de chemin et il contribue à résoudre le problème de «speed binning». En outre, ils peuvent être utilisés dans l'amélioration de l'approche classique ATPG de génération de «patterns» et elles sont indépendantes de la technologie. L'application de ces contributions peut apporter des améliorations considérables à la qualité de test IC en assurant une meilleure couverture des défauts et en aidant à augmenter le rendement de fabrication au cours de la vitesse du «binning» dans les puces IC. L’évolution en continue de la technologie en échelle nanométrique / Advancing nanometer technology scaling enables higher integration on a single chip with minimal feature size. As a consequence, the effects of signal and power integrity issues such as crosstalk noise between interconnects, power supply noise and ground bounce in the supply networks significantly increases. Also, reliability issues are eventually introduced by variations in the manufacturing process. These issues will negatively impact the timing characteristics in an integrated circuit (IC), as they give rise to delay defects. Delay-related parametric failures increase the defect escape rate, yield loss and diminish reliability rate. Hence, design-for-test techniques are employed to have a better controllability and observability on the internal nodes to easily detect and locate the faults. However, they are not always detected by the traditional fault models. In our work, we target these challenges and propose novel physical design-aware path delay test methods to deal with delay faults coming from manufacturing defects or physical design issues. They include the investigation of path delay variations in the presence of crosstalk noise, power supply noise, ground bounce and process variations. Based on this, we develop technology independent test methods for identifying the test patterns that may cause a worst-case delay on a target path. Then, we develop a dedicated test pattern generation method for path delay testing in the presence of crosstalk noise, power supply noise and ground noise. The proposed methods can be used to characterize the path speed and it helps to address the speed binning problem. Also, they can be employed in improving the classical ATPG approach of pattern generation. The application of these contributions can bring tremendous improvements to the IC test quality by ensuring better defect coverage and for an increased manufacturing yield during speed binning of IC chips.

O presente estudo tem como objetivo analisar os efeitos do uso da marca pelo titular ou por terceiros sob a ótica da integridade. O uso da marca traz consequências negativas ao próprio signo no que tange à sua integridade material, causando o desgaste da sua distinção entre marcas de concorrentes, o que faz diminuir a distância distintiva entre os sinais de uma mesma atividade econômica ou afins. Além disso, o uso da marca também pode causar a perda completa de sua unicidade, corpo distintivo da marca, chegando, às vezes, à vulgarização da mesma, tornando-se res communis omnium. Do outro lado, a integridade material da marca pode passar por processos positivos que fortalecem o seu corpo distintivo. O uso da marca com sucesso faz aumentar sua fama perante o mercado e consumidores, diferenciando-a das demais e sendo alçada ao posto de marca famosa. A fama através do uso impulsiona marcas ordinárias ao status de marcas notoriamente conhecidas ou marcas de alto renome. Ambas representam degraus superiores de integridade material em relação às marcas que são ordinariamente protegidas dentro de suas atividades comerciais. Além disso, apesar do direito de uso exclusivo oferecido às marcas registradas, tal direito não é absoluto. Ou seja, mesmo ocorrendo usos desautorizados de marcas de terceiros que ocasionem alterações na integridade material das mesmas, há usos considerados permitidos pela legislação e jurisprudência. Dessa forma, pretende-se demonstrar que o uso da marca é o fio condutor desses fenômenos. / This paper aims to analyze the effects of the use of the trademark by the owner or by third parties from the perspective of the integrity. The use of the trademark brings negative consequences to the sign itself with respect to its material integrity, causing lack of its distinctiveness among competing marks, which slims the distinctive distance between the signs of the same or related economic field. Furthermore, the use of the trademark can also cause the complete loss of its uniqueness, distinctive body of the mark, reaching sometimes the vulgarization of the same, becoming res communis omnium. On the other hand, the material integrity of the mark can undergo positive processes that enhance its distinctive body. The successful use of the mark increases its fame before the market and consumers, differentiating it from others and being raised to a level of a famous mark. The fame through use elevates the ordinary marks to the status of well-known marks or trademarks of high repute. Both represent upper rungs of material integrity towards marks that are ordinarily protected within their fields of activities. Moreover, despite the right of exclusive use offered to registered marks, such right is not absolute. That is, even occurring unauthorized uses of trademarks by third parties which cause changes in the material integrity of the same, there are uses considered permitted by law and jurisprudence. Thus, this paper intends to demonstrate that the use of the mark is the common thread of these phenomena.

O objetivo deste trabalho foi avaliar a adição de diferentes níveis de levedura (Saccharomyces cerevisiae) inativa e desidratada às rações, associados ao plasma sangüíneo e ao ácido glutâmico, sobre o desempenho e morfologia intestinal de leitões na fase inicial. Para tanto, foram realizados dois experimentos, cada um com três tratamentos de quatro repetição com 22 animais em fase de creche (21 à 59 dias), totalizando 264 leitões por experimento. Os animais foram distribuídos em delineamento em blocos casualizados nos dois experimentos. Ambos foram divididos em quatro fases experimentais correspondentes as trocas das dietas: pré - inicial 1(21-28), pré - inicial 2 (29-35), pré - inicial 3 (36-42). O experimento 1 teve os seguintes tratamentos: Ração Pré Inicial 1 - A - 5% de levedura inativa, 4% de plasma, 1% de ácido glutâmico; B - 3% de levedura inativa, 2% de levedura hidrolisada, 4% de plasma e 1% de ácido glutâmico; C - 3% de levedura inativa, 2% de levedura hidrolisada, 4% de plasma. Ração Pré Inicial 2 - A - 4% de levedura inativa, 3% de plasma, 0,8% de ácido glutâmico; B - 3% de levedura inativa, 1% de levedura hidrolisada, 3% de plasma e 0,8% de ácido glutâmico; C - 3% de levedura inativa, 1% de levedura hidrolisada, 3% de plasma. Ração Pré Inicial 3 - A - 2% de levedura inativa, 1,5% de plasma, 0,6% de ácido glutâmico; B - 2% de levedura, 0,5% de levedura hidrolisada, 1,5% de plasma e 0,6% de ácido glutâmico; C - 2% de levedura, 0,5% de levedura hidrolisada, 1,5% de plasma. E o experimento 2 teve os seguintes tratamentos: Ração Pré Inicial 1 - A - 5% de levedura inativa, 3% de plasma; B - 5% de levedura inativa, 3% de plasma e 1% de ácido glutâmico; C - 3% de levedura inativa, 2% de levedura hidrolisada, 3% de plasma e 1% de ácido glutâmico. Ração Pré Inicial 2 - A - 4% de levedura inativa, 2% de plasma; B - 4% de levedura inativa, 2% de plasma, 0,8% de ácido glutâmico; C - 3% de levedura inativa, 1% de levedura hidrolisada, 2% de plasma e 0,8% de ácido glutâmico. Ração Pré Inicial 3 - A - 2% de levedura inativa, 1,0% de plasma; B - 2% de levedura inativa, 1,0% de plasma, 0,6% de ácido glutâmico; C - 2% de levedura, 0,5% de levedura hidrolisada, 1,0% de plasma e 0,6% de ácido glutâmico. A levedura hidrolisada demonstrou aspectos positivos para sua utilização em dieta de leiões nas fases críticas pós desmama podendo promover melhora no desempenho zootécnico e na morfologia intestinal dos animais. / The objective of this study was to evaluate the addition of different levels of hidrolysed and inactive yeast (Saccharomyces cerevisiae) in feed, with spray dried blood plasma and glutamic acid on performance and intestinal morphology of weaned piglets. Two experiments were conducted, each with three treatmens, four replicates with 22 animals in the nursery phase (21 to 59 days of age), totaling 264 pigs per experiment. The piglets were distributed in randomized block design in both experiments. The experiments were divided in four phases corresponding experimental diets: pre - starter 1 (21-28), pre - starter 2 (29-35), pre - starter 3 (36-42). Experiment 1 had the following treatments: Pre starter 1 - A - 5% of inactive yeast, 4% plasma, 1% glutamic acid; B - 3% of inactive yeast, 2% hydrolyzed yeast, 4% plasma and 1% glutamic acid; C - 3% inactive yeast, 2% hydrolyzed yeast, 4% of plasma. Pre starter 2 - A - 4% inactive yeast, 3% plasma, 0.8% glutamic acid; B - 3 % inactive yeast, 1% hydrolyzate yeast, 3% plasma, 0.8% glutamic acid; C - 3% inactive yeast, 1% hydrolyzate yeast, 3% of plasma. Pre starter 3 - 2% inactive yeast, 1.5% plasma, 0.6% glutamic acid; B - 2% inactive yeast, 0.5% hydrolyzate yeast, 1.5% and plasma 0 6% glutamic acid; C - 2% inactive yeast, 0.5% hydrolyzate yeast, 1.5% plasma. And the experiment 2 had the following treatments: Pre starter 1 - A - 5% inactive yeast, 3% plasma; B - 5% inactive yeast, 3% plasma and 1% glutamic acid; C - 3% inactive yeast , 2% hydrolyzate yeast, 3% plasma and 1% glutamic acid. Pre starter 2 - A - 4% inactive yeast, 2% plasma; B - 4% inactive yeast, 2% plasma, 0.8% glutamic acid; C - 3% inactive yeast, 1% hydrolyzate yeast, 2 % plasma and 0.8% of glutamic acid. Pre starter 3 - A - 2% inactive yeast, 1.0% plasma; B - 2% inactive yeast, 1.0% plasma, 0.6% glutamic acid; C - 2% inactive yeast, 0, 5% hydrolyzate yeast 1.0% of plasma and 0.6% glutamic acid. Yeast hydrolyzate showed positive aspects to their use in diet after weaning can promote improvement in performance and intestinal morphology of animals.

Les travaux présentés dans cette thèse s'inscrivent dans le cadre du projet européen ACCENT sur la maitrise de l'intégrité de surface par la surveillance lors de l'usinage des pièces critiques aéronautiques. Des études antérieures ont montrées que des anomalies générées lors de l'usinage peuvent induire un abattement sur la tenue en fatigue des pièces. Dans ce contexte, l'objectif de ces travaux est de modéliser la relation entre l'intégrité de surface et les signaux enregistrés lors du perçage de l'Udimet®720. A partir d'une démarche expérimentale basée sur le Couple-Outil-Matière et les plans d'expériences, une caractérisation de l'usure de l'outil, de l'intégrité de surface et des signaux enregistrés a été effectuées en fonction des conditions d‘usinage et du contexte de l'opération (lubrifiant, dureté matière). Cette caractérisation à permis d'établir des corrélations entre les caractéristiques de l'intégrité de surface et celles des signaux. Ces corrélations ont été modélisées par des méthodes directes et statistiques, afin de mettre en avant la pertinence des capteurs de puissance, d'efforts et d'accélération par rapport aux anomalies d'usinage. Ainsi les capteurs permettent la prédiction de la couche de matière affectée par l'opération quelque soit le contexte d'usinage. / The works presented in this thesis join within the framework of the European project ACCENT on surface integrity control by process monitoring during the manufacturing of aeronautical critical parts.Previous studies showed that anomalies generated during the manufacturing process can reduce the fatigue lifecycle. In this context, the objective of this work is to model the relation between the surface integrity and the signals recorded during the drilling of Udimet®720. From an experimental approach based on Couple-Tool-Material and design of experiments, a characterization of tool wear, surface integrity and recorded signals was made according to the cutting conditions and manufacturing disturbances (lubricant, material hardness).This characterization establishes correlations between the characteristics of surface integrity and those of signals. These correlations were modeled by direct and statistical methods, to advance the relevance of sensors (power, efforts and acceleration) with regard to manufacturing disturbances. So the sensors allow the prediction of the thermo-mechanically affected layer generated by the operation in most of manufacturing conditions.

Made available in DSpace on 2015-07-15T13:31:39Z (GMT). No. of bitstreams: 1 Dissertacao Vilara Mendes.pdf: 2710775 bytes, checksum: 512ad33d9a304b5c92eef7518ed26eba (MD5) Previous issue date: 2007-01-16 / This study has as investigation object of the integrity of the care in the process of work of the Teams of Health of Family (ESF) in the Jequi? city. It has the objectives to understand the senses and meanings of the integrity of the care in health in the process of work of the respective teams; to analyze the devices that guide the integral care to health (bond, reception,responsibility and resolution) and to identify the implications of the integrity of the care to the health in the process of the workers' of health work. It is a qualitative research, in an approximate perspective of the dialectic; method; it was used as technique s collection the semi-structured interview, the systematic observation and the analysis of official documents.The method of analysis approached to the hermeneutics-dialectics. The people of the study were twenty workers of health and seven users of the teams of health of the family. The results showed that the practices of health developed in some teams of health of the family seem contradictory to the integral service, still sustained in the doctor-centered model, mainly oriented for the hard technologies light-hard. However it is possible to notice some sensibility of guiding the work process for a perspective to the light technologies (relational practices),trying to develop their practices starting from an enlarged vision of the individual as bearer of foreseen needs and unexpected. The public litics of municipal health are a limit to be overcome in the sense of reaching the profile change in the ganization structure of the attention to the health. Was ended, therefore that for materialization of the integrity of the care in the Municipal district of Jequi?, the development of competences is demanded in the work process in health as well as a politics of articulate formation to the practice for construction of collective projects ntegrated to the care in health, in that workers and managers of health and users are co-responsible for the production of a knowledge - to do, aiming at to give positive answers to the needs and the user's demands - family in a humanized way. / Este Estudo tem como objeto de investiga??o a Integralidade do cuidado no processo de trabalho das Equipes de Sa?de da fam?lia no munic?pio de Jequi?-BA, tendo como objetivos compreender os sentidos e significados da Integralidade do cuidado em sa?de no processo de trabalho das respectivas equipes; analisar os dispositivos que orientam o cuidado integral a sa?de (v?nculo, acolhimento, responsabiliza??o e resolubilidade) e identificar as implica??es da integralidade do cuidado ? sa?de no decorres do processo de trabalho dos trabalhadores de sa?de. Trata-se de uma pesquisa qualitativa, em uma perspectiva aproximada do m?todo dial?tico, onde foi utilizado como t?cnica de coleta de dados ? entrevista semi-estruturada, a observa??o sistem?tica e an?lise de documentos oficiais. O m?todo de an?lise dos dados foi ? hermen?utica-dial?tica. Os sujeitos do estudo foram vinte trabalhadores de sa?de e sete usu?rios das equipes de sa?de da fam?lia. Os resultados mostraram que as pr?ticas de sa?de desenvolvidas em algumas equipes de sa?de da fam?lia se apresentam contradit?rias ao que se prop?e o atendimento integral, encontrando-se ainda sustentada no modelo m?dico, principalmente orientado pelas tecnologias duras e leve-duras. Todavia ? poss?vel perceber alguma sensibiliza??o no sentido de orientar o processo de trabalho para uma perspectiva voltada para as tecnologias leves (pr?ticas relacionais) procurando desenvolver as suas pr?ticas a partir de uma vis?o ampliada do individuo como portador de necessidades previstas e imprevis?veis. As Pol?ticas p?blicas de sa?de municipal ? um limite a ser uperado no sentido de alcan?ar a mudan?a de perfil na estrutura de organiza??o da aten??o a sa?de. Conclui-se, portanto que para concretiza??o da integralidade do cuidado no Munic?pio de Jequi?, exige-se o desenvolvimento de compet?ncias no processo de trabalho em sa?de assim como uma pol?tica de forma??o articulada ? pr?tica para constru??o de projetos coletivos integrados ao cuidado em sa?de, em que trabalhadores e gestores de sa?de e usu?rios sejam co-respons?veis pela produ??o de um saber fazer objetivando dar respostas positivas ?s necessidades e demandas do usu?rio fam?lia de forma humanizada.

Purpose: Can luxury fashion brands use websites and web-shops and still keep a sense of drama and exclusivity around their brand and at the same time avoid brand dilution?Background: The e-commerce opened up for new possibilities for the luxury fashion brands but due to the dotcom crash around the year of 2000 did many of them become reluctant to the Internet as a selling channel. LVMH was one of the first in this genre to start up a web- shop. It name was eluxury (eluxury.com), and sold products from LVMH’s brands like Louis Vuitton, Dior and Donna Karan. It started off in the US market and then spread to France and the United Kingdom. This inspired other brands like Gucci and Armani to also invest in e-commerce. Even though the success of these web-shops is there still an ongoing debate about whether or not luxury brands should adopt e-commerce. The major concern is the dilution of features like exclusivity and prestige of the brands, if they are present in this channel.Method: To meet the purpose a qualitative research approach was chosen. The qualitative data was collected through eight in-depth interviews with luxury fashion interested Swedish females. The answers from the interviews generated a picture of their online shopping habits, and the likes and dislikes of the websites and web-shops of Louis Vuitton, Burberry, Dior and Gucci. In addition it showed what makes a web-shop exclusive and well designed from a consumer/visitor point of view.Conclusion: The result of this research showed that it is good for luxury fashion brands to have distribution online because it makes the products a lot easier to get hold of for the consumers. Although there were several criteria that was needed to be fulfilled in order to design and create a well functioning and good web-shop. It was evident from the result of the study that the Internet can really be a good distribution channel, with only a little risk of brand dilution depending on how the web-shop is designed. To summarize, we say that a good website and web-shop meeting the criteria of the consumers can really create a stronger brand image and online sales, although a luxury fashion brand should also have good physical stores, a web-shop can in many ways really be a very suitable complement for marketing and distribution. / Program: Magisterutbildning i fashion management med inriktning modemarknadsföring

Då konkurrensen mellan företag inom kläd- och modebranschen är hög erbjuder mångaföretag kundklubbar och lojalitetsprogram till sina kunder. Kundklubbar ska vara ett sättför företag att differentiera sig, men blir det en differentiering när de flesta företagerbjuder sina kunder liknande kundklubbar och lojalitetsprogram?För att differentiera sig har företag inom branschen utvidgat sina kundklubbar ochlojalitetsprogram, men med åtgärder som de flesta företag kan använda inom branschen,vilket gör att differentieringen uteblir. Den svenska matvarukedjan ICA har tagitkundklubben till en ny nivå och erbjuder sina kunder ”mina varor”. Utifrån kunderstidigare köp får de sedan erbjudanden som är personliga. Varje erbjudande blir unikt.Frågan är om det finns ett intresse hos konsumenter inom kläd- och modebranschen förett anpassat erbjudande, för att göra kundklubbars erbjudanden mer unika. För att det skagenomföras behöver företag registrera kunders köpvanor och beteenden. Kan erbjudandetdå utgöra ett hot mot kunders integritet?Syftet med uppsatsen är att undersöka vad kunder inom kläd- och modebranschen anserom dagens kundklubbar och hur de ställer sig till att införa personanpassade erbjudanden,likt ICA:s, i kläd- och modebranschen. Målet är att undersöka om kunden har ett intresseför en ny form av kundklubb i kläd- och modebranschen.Frågeställningarna som ska undersökas är:Huvudfråga:Hur ser kunden på personanpassade erbjudanden i kläd- och modebranschen?Underfrågor:Hur ser kunden på de erbjudanden som kundklubbar erbjuder idag?Hur påverkas kunder av det faktum att företag måste registrera deras köpvanor för attkunna erbjuda personliga erbjudanden?För att besvara frågeställningarna har en fallstudie utförts med hjälp av en fokusgruppsamt fem personliga intervjuer. Undersökningen har visat att konsumenter inom kläd- ochmodebranschen relaterar kundklubbar med erbjudanden för att få dig som kund att handlamer, vilket konsumenterna i vissa fall också gör. Det visade sig också att konsumenterinom branschen inte tror att det skulle vara lika lätt att anpassa personliga erbjudanden påkläder och mode som det är på dagligvaror. Dessutom är dagens konsumenter vana vidatt företag registrerar deras köp och tycker att det är acceptabelt så länge företag intesamlar för personlig information i marknadsföringssyfte.

Neste trabalho, estudou-se a integridade superficial durante o torneamento de um ferro fundido nodular com carbonetos, considerando a heterogeneidade microestrutural (fração volumétrica, tamanho e morfologia de grafita e dos carbonetos) e os efeitos dos parâmetros de corte (avanço, velocidade de corte e profundidade de corte), baseados num planejamento fatorial fracionário 24-1. Este texto apresenta, numa primeira parte, uma revisão baseada em referências bibliográficas clássicas da engenharia de superfícies, na tentativa de definir os conceitos que compõem a integridade da superfície. Posteriormente, descrevem-se os resultados de ensaios preliminares, realizados com a finalidade avaliar os níveis do processo e os efeitos desses parâmetros na integridade da superfície. Finalmente, realizaram-se os ensaios de usinagem em corpos-de-prova de ferro fundido nodular com carboneto, nos diâmetros de 80 mm e 140mm. Durante os ensaios de torneamento empregaram-se duas velocidades de corte (60 m/min e 180 m/min), dois avanços (0,1 mm/rev e 0,3 mm/rev) e duas profundidades de corte (0,2 mm e 0,3 mm). Após os ensaios de usinagem, foram realizadas: a avaliação das propriedades do material usinado (dureza e microestrutura), a análise de topografia da superfície usinada mediante avaliação da rugosidade, e a avaliação da influência dos parâmetros de usinagem na rugosidade. Encontrou-se uma dependência estatisticamente significativa da variação nas propriedades mecânicas dos corpos-de-prova em função da microestrutura, e mostraram-se os efeitos dessas variações em termos da integridade da superfície usinada. / In this work, the surface integrity of a ductile cast iron with carbides was studied during turning operations, considering the microstructural heterogeneity (volume fraction, size and morphology of the graphite and carbides) and the effect of the machining parameters (feed, cutting speed and depth of cut), based on a fractional factorial design 24-1. This work presents, initially, a literature review based on classic works on surface engineering, as an attempt to define the main concepts of surface integrity. Later, the results of preliminary test are described, which were conducted in order to define the process levels and the effects of these levels on the surface integrity. Finally, turning tests were conducted on specimens of ductile iron with carbides, at diameters of 80 and 140 mm. Two cutting speeds (60 m/min and 180 m/min), two feeds (0,1 mm/rev and 0,3 mm/rev) and two depths of cut (0,2 mm and 0,3 mm) were selected during the tests. Machined specimens were analyzed in terms of the properties of the machined material (hardness and microstructure) and of the roughness of the machined surface. The effect of the machining parameters on the roughness was also studied. A statistically significant dependence was observed for the properties of the machined specimens as a function of the microstructure and the effect of these properties on the surface integrity is presented.

Advances in dynamic fracture modelling have become more frequent due to increases in computer speed, meaning that its application to industrial problems has become viable. From this, the author has reviewed current literature in terms of graphite material properties, structural dynamics, fracture mechanics and modelling methodologies to be able to address operational issues related to the ageing of Advanced Gas-cooled Reactor (AGR) cores. In particular, the experimentally observed Prompt Secondary Cracking (PSC) of graphite moderator bricks which has yet to be observed within operational reactors, with the objective of supporting their plant life extension. A method known as eXtended Finite Element Method with Cohesive Zones (XCZM) was developed within Code_Aster open-source FEM software. This enabled the incorporation of velocity toughening, irradiation-induced material degradation effects and multiple 3D dynamic crack initiations, propagations and arrests into a single model, which covers the major known attributes of the PSC mechanism. Whilst developing XCZM, several publications were produced. This started with first demonstrating XCZM's ability to model the PSC mechanism in 2D and consequently that methane holes have a noticeable effect on crack propagation speeds. Following on from this, XCZM was benchmarked in 2D against literature experiments and available model data which consequently highlighted that velocity toughening was an integral feature in producing energetically correct fracture speeds. Leading on from this, XCZM was taken into 3D and demonstrated that it produced experimentally observed bifurcation angle from a literature example. This meant that when a 3D graphite brick was modelled that the crack profile was equivalent to an accepted quasi-static profile. As a consequence of this validation, the XCZM approach was able to model PSC and give insight into features that could not be investigated previously including: finer-scale heterogeneous effects on a dynamic crack profile, comparison between Primary and Secondary crack profiles and also, 3D crack interaction with a methane hole, including insight into possible crack arrest. XCZM was shown to improve upon previous 2D models of experiments that showed the plausibility of PSC; this was achieved by eliminating the need for user intervention and also incorporation of irradiation damage effects through User-defined Material properties (UMAT). Finally, while applying XCZM to a full-scale 3D graphite brick including reactor effects, it was shown that PSC is likely to occur under LEFM assumptions and that the Secondary crack initiates before the Primary crack arrests axially meaning that modal analysis would not be able to fully model PSC.