Stationary shoulder friction stir welding (SSFSW) is a recently developed variant of conventional friction stir welding (FSW). Recent studies have shown that SSFSW can join high strength aluminum alloys with improved mechanical strength and reduced distortion as a result of a narrower and more uniform thermal profile. However, a lack of understanding on the residual stress development in the SSFSW process makes it difficult to assess the structural integrity and delays a widespread application of this technique to industry. This dissertation reports the first systematic investigation into the development of residual stress induced by the SSFSW process and comparison between SSFSW and FSW techniques. Welding residual stresses were experimentally assessed with both the contour method and neutron diffraction. The weld microstructure and hardness distributions were characterized and used to understand the formation of residual stresses during the welding process. The results have shown that for both FSW and SSFSW processes, the residual stresses distribute in the form of ‘M’ shaped profile while the magnitude and size of tensile residual stress zone were effectively reduced (by 25%) in the SSFSW process, even when input welding power was identical. Other improvements seen in the SSFSW process include a reduction in the heat affected zone width, an increase in the minimum hardness and a more uniform through-thickness microstructure and hardness. The dominating welding process parameter affecting the welding residual stress was travel speed as compared to rotation speed and tool downforce. With a 90 degree shaped shoulder, SSFSW has been shown to produce defect-free T-sections by dual fillet welds. For these components, an asymmetrical distribution of microstructure, hardness and residual stresses were found as a consequence of the thermal effects induced by second weld on the first weld. The material softening caused by the first weld provides the potential of utilizing a lower heat input on the subsequent pass so as to optimize the welding parameters.

Residual stresses are the stresses which are present within a component without any external load. They can be introduced through any number of manufacturing processes and in-service conditions, meaning that they are almost ubiquitous in engineering components. The characterisation of residual stress is an important field of research particularly in an engineering context since the effects of residual stress sum with the loads. As a result, the performance of a component can be greatly enhanced, or significantly reduced, by the presence of residual stress depending on the sign of the stress and the applied load. In this EngD thesis the focus has been on the development of residual stress through the manufacturing processes of aero-engine forgings, specifically the turbine disc. The forgings studied were sub-scale geometries of the disc, forged from the nickel-base superalloy RR1000. The overall aim of this work is to improve the understanding of the residual stress generation and relaxation through implementation of advanced experimental characterisation techniques, with a view to improving current stress predicting process modelling capabilities. With this in mind the work has focussed on the use of neutron diffraction and the contour method to characterise residual stress experimentally, while residual stress predictions have been made using finite element modelling. The findings of this research indicated that very large residual stresses were generated as a result of the quenching process, and that these stresses were then relaxed and redistributed by ageing heat treatments and material removal by machining. The results obtained through the two experimental techniques exhibited very strong agreement, indicated a robust experimental process. Comparisons to the finite element predictions highlighted some issues with the current model; in particular it was found that the simulation of quenching could be improved by better definition of the heat transfer at the surface. Furthermore, the level of stress relaxation during ageing was consistently over predicted in the model. This result is thought to be the result of an over-prediction of the level primary creep in the alloy. Subsequent studies will investigate this behaviour further using the newly developed in-situ heat treatment capabilities which have developed as part of this research.

The worldwide preferred method for rail joining is welding; flash butt welding (FBW) and thermite welding (TW) are the two main welding methods used for joining continuous welded rail (CWR) tracks. However, the welds still represent a discontinuity in the track structure due to variations in microstructure, mechanical properties and residual stress levels with respect to the parent rail. These variations can play significant roles in increasing the risk of weld failure under service conditions. In order to better understand how FBW parameters affect these variations, the two main parameters; number of preheating cycles and upsetting forces were varied in three 56E1 rail welds, welded by a stationary FBW machine. Besides, these variations were systematically compared with those that occur in a standard thermite 60E2 rail weld. The thermite weld showed a heat affected zone (HAZ) extent much greater than those measured in the flash butt welds. The flash butt rail weld with a greater upsetting force (Standard Crushed) showed a HAZ extent larger than those in the other two welds (Standard Uncrushed and Narrow-HAZ Crushed), while the weld with fewer preheating cycles (Narrow-HAZ Crushed) showed a smaller extent of the HAZ.All welds showed pearlite colonies with proeutectoid ferrite at the prior austenite grain boundaries in the weld centre, and in the thermite weld zone. The rest zones across the welds exhibited almost fully pearlitic microstructures, but the pearlite at nearly the visible HAZ extents was partially spheroidised. The partially spheroidization zone had the minimum hardness across each of the thermite and flash butt welds. The Narrow-HAZ Crushed weld showed hardness in the weld centre, on average, higher than that of the parent metal. Moreover, the averaged hardness levels in this weld were significantly higher than those in the other two welds. However, these levels in the Standard Crushed weld were slightly lower than those in the Standard Uncrushed weld. Although the visible HAZ extent coincided with the point of minimum hardness, the residual stresses arising from the welds seem to extend much further. Contour Method and laboratory X-ray diffraction techniques were used together to measure the residual stress components across the thermite and flash butt rail welds. The longitudinal residual stress distribution showed tension in the web region along with compression in the head and foot regions of the rail welds. The vertical stress distribution across the flash butt welds was generally similar, and the maximum tensile stress values were comparable to those in the longitudinal direction. While the maximum values of the longitudinal tensile stress increased with decreasing the HAZ widths, these values in the vertical direction were significantly unaffected. However, the longitudinal and vertical tensile residual stresses typically promote the vertical straight-break and horizontal split web failure modes respectively.

O Sexteto - Seis prelúdios e um enigma de Francisco Mignone foi selecionado como tema por ser uma obra pouco conhecida e que merece ser resgatada. Uma edição digitalizada foi realizada com o intuito de facilitar sua difusão. A obra está em linguagem atonal, mas faz uso também do cromatismo e de algumas incursões modais. As novas linguagens surgidas desde o começo do século XX requerem outras premissas do intérprete. O contorno de superfície será investigado utilizando a Teoria do Contorno de Michael Friedmann, com o intuito de produzir inteligibilidade na linha, bem como a possibilidade de inter-relacionar o material estudado, algo fundamental na estruturação de uma performance. O intérprete deve usar seu conhecimento e técnicas analíticas adequadas que permitam buscar elementos potencialmente significativos, com a finalidade de construir uma performance, assim como os aspectos inerentes da análise tradicional que contribuem para edificar uma performance expressiva e alicerçada nos elementos estruturais da obra. Os diálogos entre análise e performance contribuíram sobremaneira para o entendimento do processo. A adoção de uma nova ferramenta, como a Teoria do Contorno, ajudou-me como intérprete a identificar na estrutura eventos que pareciam desconexos. Alguns parâmetros não são identificáveis sem a teoria, com isso ela passa a representar uma ferramenta prática para o intérprete. A análise criteriosa e seletiva voltada para a performance e a investigação da biografia e das influências de escrita proporcionaram um entendimento abrangente da obra. / The Sextet - Seis prelúdios e um enigma [six preludes and a enigma] by Francisco Mignone was selected as theme because it is a work that is not well known and deserves to be rescued. A digitalized version was realized in order to diffuse it. The work is in atonal language, but also uses chromaticism, and sometimes modal language. The new vocabulary that emerged since the beginning of the 20th century requires specific premises of the interpreter. The surface contour will be investigated using Michael Friedmann\'s Contour Theory in order to produce melodic intelligibility as well as the ability to interrelate the studied material, which is fundamental in structuring a performance. Interpreters must use their knowledge and appropriate analytical techniques that allow for searching potentially significant elements for the purpose of constructing a performance, as well as aspects of traditional analysis which contribute to building a meaningful and grounded performance in respect to the structural elements of the work. The dialogues between analysis and performance contributed greatly to the understanding of the process. The adoption of a new tool such as Contour Theory helped me as an interpreter to identify events that seemed unrelated in the structure. Some parameters are not identifiable without the theory; theory represents a practical tool for the interpreter. A careful and selective analysis focused on performance and the research of biography and writing influences provided a comprehensive understanding of the work

Os centros operacionais e de pesquisa em previsão numérica do tempo geralmente trabalham com uma grande quantidade de dados complexos multivariados, tendo que interpretá-los num curto espaço de tempo. Técnicas de visualização científica podem ser utilizadas para ajudar a entender o comportamento atmosférico. Este trabalho descreve a arquitetura e as facilidades apresentadas pelo sistema VisualMet, que foi implementado com base em um estudo das tarefas desenvolvidas pelos meteorologistas responsáveis pelo 8º Distrito de Meteorologia, em Porto Alegre. Este centro coleta dados meteorológicos três vezes ao dia, de 32 estações locais, e recebe dados similares do Instituto Nacional de Meteorologia, localizado em Brasília, e do National Meteorological Center, localizado nos Estados Unidos. Tais dados são resultados de observações de variáveis tais como temperatura, pressão, velocidade do vento e tipos de nuvens. As tarefas dos meteorologistas e as classes de dados foram observadas e analisadas para definir as características do sistema. A arquitetura e a implementação do VisualMet seguem, respectivamente, uma abordagem orientada a ferramentas e o paradigma de programação orientada a objetos. Dados obtidos das estações meteorológicas são instancias de uma classe chamada "Entidade". Três outras classes de objetos representando ferramentas que suportam as tarefas dos meteorologistas foram modeladas. Os objetos no sistema são apresentados ao usuário através de duas janelas, "Base de Entidades" e " Base de Ferramentas". A implementação da "Base de Ferramentas" inclui ferramentas de mapeamento (para produzir mapas de contorno, mapas de ícones e gráficos), ferramentas de armazenamento (para guardar e recuperar imagens geradas pelo sistema) e uma ferramenta de consulta (para ler valores de variáveis de estações selecionadas). E dada especial atenção a ferramenta de mapa de contorno, onde foi utilizado o método Multiquádrico para interpolação de dados. O trabalho apresenta ainda um estudo sobre métodos de interpolação de dados esparsos, antes de descrever detalhadamente os resultados obtidos com a ferramenta de mapa de contorno. Estes resultados (imagens) são discutidos e comparados com mapas gerados manualmente por meteorologistas do 8º Distrito de Meteorologia. Possíveis extensões do presente trabalho são também abordadas. / The weather forecast centers deal with a great volume of complex multivariate data, which usually have to be understood within short time. Scientific visualization techniques can be used to support both daily forecasting and meteorological research. This work reports the architecture and facilities of a system, named VisualMet, that was implemented based on a case study of the tasks accomplished by the meteorologists responsible for the 8th Meteorological District, in the South of Brazil. This center collects meteorological data three times a day from 32 local stations and receives similar data from both the National Institute of Meteorology, located in Brasilia, and National Meteorological Center, located in the United States of America. Such data result from observation of variables like temperature, pressure, wind velocity, and type of clouds. The tasks of meteorologists and the classes of application data were observed to define system requirements. The architecture and implementation of Visual- Met follow the tool-oriented approach and object-oriented paradigm, respectively. Data taken from meteorological stations are instances of a class named Entity. Three other classes of tools which support the meteorologists' tasks are modeled. Objects in the system are presented to the user through two windows, "Entities Base" and "Tools Base". Current implementation of the "Tools Base" contains mapping tools (to produce contour maps, icons maps and graphs), recording tools (to save and load images generated by the system) and a query tool (to read variables values of selected stations). The results of applying the multiquadric method to interpolate data for the construction of contour maps are also discussed. Before describing the results obtained with the multiquadric method, this work also presents a study on interpolation methods for scattered data. The results (images) obtained with the contour map tool are discussed and compared with the maps drawn by the meteorologists of the 8th Meteorological District. Possible extensions to this work are also presented.

We present a method for extracting contours from digital images, using techniques from computational geometry. Our approach is different from traditional pixel-based methods in image processing. Instead of working directly with pixels, we extract a set of oriented feature points from the input digital images, then apply classical geometric techniques, such as clustering, linking, and simplification, to find contours among these points. Experiments on synthetic and natural images show that our method can effectively extract contours, even from images with considerable noise; moreover, the extracted contours have a very compact representation.

This paper deals with generalization fo Gershgorin's theorem. This theorem is investigated and generalized in terms of contour integrals, directed graphs, convex analysis, and clock matrices. These results are shown to apply to some specified matrices such as stable and stochastic matrices and some examples will show the relationship of eigenvalue inclusion regions among them.

Charles Ives is commonly referred to as the "Father of American Music." The implication is one that Ives himself would agree with, that he wrote purely American ideas from his own environment without reference to other styles or methods, in particular the widespread European tradition. Some composers, like Aaron Copland and Roger Sessions, created an American sonority by incorporating the concepts of musical construction they studied at the Paris Conservatoire. Ives, conversely, received no instruction in Europe, but the techniques so prevalent in the music of the French art song are found in certain songs written by Ives. Though he claimed no European influence, however, he used the late nineteenth century French song style in some of his songs, and he also borrowed tunes from the French composers. This study identifies significant trademarks of eighteenth century French song and the stylistic traits associated with a variety of prominent composers of the time. Ives's childhood musical influences, his church position, and his studies at Yale University will establish a relationship between Ives and the French musical ideas. The primary source for his songs is his collection entitled 114 Songs. Ives gathered his songs and put them into one collection which included Four French Songs. Through the analysis of several songs, including the four French songs written by Ives and three comparisons of songs by Ives with songs by French composers, it becomes evident that Ives was influenced, to a certain extent, by French music and used many techniques of the style.

Encoding the shape of objects within the visual environment is one of the important roles of the visual system. This thesis investigates the proposition that human sensitivity to a broad range of closed-contour shapes is underpinned by multiple shape channels (Loffler, Wilson, & Wilkinson, 2003). Radial frequency (RF) contours are a novel type of stimulus that can be used to represent simple and complex shapes; they are created by sinusoidally modulating the radius of a circle, where the number of cycles of modulation defines the RF number (Wilkinson, Wilson, & Habak, 1998). This thesis uses RF contours to enhance our understanding of the visual processes which support shape perception. The first part of the thesis combines low and high RF components, which Loffler et al. have suggested are detected by separate global and local processes respectively, onto a single contour and shows that, even when combined, the components are detected independently at threshold. The second part of the thesis combines low RF components from across the range where global processing has been demonstrated (up to approximately RF10) onto a single contour in order to test for interactions between them. The resulting data reveal that multiple narrow-band contour shape channels are required to account for performance, and also indicate that these shape channels have inhibitory connections between them. The third part of the thesis examines the local characteristics which are used to represent shape information within these channels. The results show that both the breadth (polar angle subtended) of individual curvature features, and their relative angular positions (in relation to object centre) are important for representing RF shapes; however, processing is IV not tuned for object size, or for modulation amplitude. In addition, we show that luminance and contrast cues are effectively combined at the level where these patterns are detected, indicating a single later processing stage is adequate to explain performance for these pattern characteristics. Overall the findings show that narrow-band shape channels are a useful way to explain sensitivity to a broad range of closed-contour shapes. Modifications to the current RF detection model (Poirier & Wilson, 2006) are required to incorporate inhibitory connections between shape channels and also, to accommodate the effective integration of luminance and contrast cues.

Se situant à l'interface de la prosodie et du discours, notre recherche a pour objet de déterminer le domaine de variabilité phonétique et la valeur discursive d'un contour intonatif du français : l'intonation d'implication, au moyen de l'observation écologique de l'usage qu'en font les locuteurs dans un corpus fermé de débat radiophonique. A partir de l'identification auditive des occurrences de l'intonation d'implication du corpus en fonction de la description qu'en donne Delattre (1966) nous proposons une analyse qualitative et quantitative de la variabilité de réalisation phonétique de ce contour. Nous montrons que, contre toute attente, ces réalisations sont très souvent confondues avec celles du contour montant continuatif et que l'alignement du pic de fréquence fondamentale sur le noyau syllabique de la dernière syllabe du contour (à gauche pour l'implication, à droite pour le continuatif) est déterminant pour leur différenciation. Nous montrons également que l'intonation d'implication est souvent confondue avec un autre contour montant-descendant dont le pic de fréquence est aligné avec la syllabe pénultième. Une analyse discursive approfondie, menée grâce au modèle proposé par l'Ecole de Genève (Roulet et al., 2001) nous permet de mettre en évidence l'usage spécifique, interactif et argumentatif, que font de ce contour les participants au débat radiophonique. La synthèse de nos analyses prosodique et discursive nous permet de proposer une interprétation compositionnelle de la valeur pragmatique de l'intonation d'implication.