Les travaux de cette thèse concernent la simulation numérique de la propagation acoustique dans un fluide en écoulement, en régime périodique établi. Le modèle retenu est l'équation de Galbrun, qui modélise la propagation linéaire d'ondes en présence d'un écoulement de fluide parfait en évolution adiabatique et porte sur le déplacement lagrangien. L'analyse mathématique montre qu'une méthode d'éléments finis nodaux ne permet pas, en général, d'approcher la solution de l'équation, les résultats étant alors fortement pollués par des modes numériques "parasites". Dans la première partie de la thèse, nous proposons une méthode de régularisation de l'équation pour laquelle nous prouvons la convergence d'une approximation par éléments finis nodaux pour des problèmes de diffraction dans un conduit en présence d'écoulements subsoniques uniforme ou cisaillé. La deuxième partie du document est consacrée à la construction et l'étude de couches absorbantes parfaitement adaptées, dites PML, pour le rayonnement d'une source localisée en présence d'un écoulement uniforme et dans un conduit. Nous traitons successivement le cas d'une source irrotationnelle, qui conduit à un problème scalaire, et celui d'une source quelconque. Un principe d'absorption limite est établi dans le cas général et nous démontrons un résultat de convergence exponentielle de la méthode de PML en fonction de la longueur des couches. Des résultats numériques illustrant ces approches sont présentés.

Cette thèse a porté sur la réalisation et la caractérisation d'une source paramétrique guidée en GaAs/AlGaAs. Grâce à son design, basé sur la biréfringence de forme, celle-ci permet la génération paramétrique sur une gamme spectrale allant de 1.2 à 2.4 µm. Cette propriété optique et sa taille réduite font d'un tel dispositif un candidat pour la fabrication d'un oscillateur paramétrique optique intégré. Néanmoins, au cours de sa fabrication, les pertes optiques guidées augmentent de 0.1 à 0.5 cm-1 suite à l'oxydation sélective des couches riches en aluminium, les transformant en AlOx. A travers une étude par microscopie électronique en transmission, nous avons tout d'abord caractérisé les propriétés structurales et chimiques de l'AlOx et des interfaces GaAs/AlOx. Nous avons ainsi constaté une augmentation de la rugosité de ces interfaces et une modification locale des couches de GaAs induites par l'étape d'oxydation. Dans un second temps, nous avons caractérisé certaines propriétés optiques des guides d'ondes. Un calcul semi-analytique nous a permis d'établir la valeur des pertes de propagation, en bon accord avec les mesures expérimentales, induite par la rugosité des interfaces GaAs/AlOx. Nous avons ensuite établi les conditions d'oxydation optimales en mesurant systématiquement les pertes de propagation. Nous avons caractérisé les performances de notre source en effectuant la première mesure d'amplification paramétrique dans un guide d'ondes semi-conducteur. Le coefficient de gain paramétrique mesuré, compatible avec l'obtention de l'oscillation paramétrique, nous a amené à concevoir, fabriquer et caractériser différentes cavités résonnantes.

Ce manuscrit, divisé en cinq chapitres, présente les différents aspects de ce travail. Le premier<br />chapitre décrit le silicium poreux et sa réalisation, les différents paramètres de formation,<br />ses propriétés structurales. Les propriétés de luminescence des ces ions (Erbium et Ytterbium)<br />sont exposées par la suite. Enfin, un état de l'art est détaillé sur les amplificateurs optiques dopés<br />Erbium déjà réalisés à partir de silicium poreux ainsi qu'à partir d'autres matériaux.<br />Le deuxième chapitre présente les conditions expérimentales d'élaboration des guides plans et<br />canaux en silicium poreux et les conditions de dopage et/ou codopage ainsi que les traitements<br />thermiques. Les méthodes de mesures de l'indice de réfraction, la photoluminescence et la photoluminescence<br />résolue en temps sont présentées. Les observations en champ proche et les mesures<br />des pertes ainsi que les mesures de gain optique sont également exposées.<br />Dans le troisième chapitre, les profils de concentration des ions terres rares pour les guides plans<br />et canaux sont présentés et discutés. Dans ce chapitre, un accent particulier estmis sur la variation<br />de l'indice de réfraction en fonction des conditions d'anodisation de dopage et des traitements<br />thermiques.<br />Le quatrième chapitre est consacré à l'étude des guides dopés et codopés par photoluminescence<br />et photoluminescence résolue en temps pour montrer l'activation des ions Erbium ainsi<br />que la détermination de la durée de vie du niveau métastable 4I13/2. Ces résultats vont nous<br />permettre d'optimiser la meilleure concentration d'Ytterbium pour le codopage ainsi que d'expliquer<br />les mécanismes d'excitation des ions Erbium. La concentration des ions Erbium actifs<br />dans les guides sera déterminée.<br />Le dernier chapitre décrit les observations en champ proche et les mesures des pertes pour les<br />guides ainsi réalisés. Le gain on/off dans les guides, définie comme étant le rapport de l'intensité<br />lumineuse du sortie avec pompage à 980 nm sur la puissance du signal de sortie sans pompage, a<br />été mesuré et exploité pour les guides codopés avec différentes concentrations d'Ytterbium. Les<br />variations du gain en fonction de la longueur d'onde sont présentées.

<p>Products are displayed in a shelf to market and sell to the public. It creates an interest and attracts people towards it. Likewise, any country or city can showcase itself by using Web over the internet which will attract the tourists from around the world. This example can be used for the city of Hyderabad. Hyderabad has truly become an international city and there are many multinational companies establishing themselves. It is rapidly becoming a hot spot for tourists from around the world because of its exotic locations and facilities provided by the government. The city has been famous for historical monuments and culture, but in the recent years it has developed into a world class IT destination for many multinational IT companies and due to this it has attained world recognition on the global scenario. The time is to reap the benefits of this image and promote the city’s tourist sector by globally marketing the tourist attractions, facilities and services in an innovative and better way so that tourists from around the world visit the city and thereby contribute to the country’s economy with the foreign currency.</p><p>This research deals with developing a Web-based GIS application that can promote the city’s tourist activities and also provide the users with an innovative way to access the spatial content of the city. GIS content forms the core component of this application as it provides the users with the spatial information about the place that is very close to reality. It supports the human tendency of “What you see is what you believe” by displaying the spatial information on the map. The application has been developed with the latest mapping server technology provided by Environmental Science Research Institute’s ArcIMS 9.1. This server software provides simple and easy methods to launch a Web-based GIS application over the Internet.</p>

<p>The aim with this archive guide is to give a guide to Karl-Anders Wollter’s film collection at Grängesberg Film archive. Karl-Anders Wollter worked between 1962–1993 for the State Department and mainly outside Sweden. The film collection consists of 67 films regarding his work, holidays and family life. In his work as a diplomat Wollter visited a lot of different places around the world, but he also travelled and made some trips with hisfamily. The collection also consists of footage from state visits, installations, negotiations in conflicts and inter-national conferences with politicians. Altogether the film collection gives not only a good view of how the life as a diplomat might be, but also of the development of the society and footage over villages and minor villages both in Sweden and other countries. This archive guide could thus serve as a guide both to those who are interested in the life as a diplomat, politic – and civic life and for those who are interested in cities and minor village’s devel-opment over time. This archive guide can also serve as a guide for those who are looking for film footage for various documentaries.</p>

<p>Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. The unit cell of the active reflect-array consists of an amplifying active reflect-antenna designed using a novel dual polarized microstrip-T coupled patch antenna. Two modelling approaches are proposed for the active reflect-antenna and the modelling methods are compared with the experiments.</p><p>A computationally efficient analysis of an H-slot in the ground plane of a microstripline is carried out using a transmission line model. To improve the accuracy in the resonant region of the H-slot and retaining the computational efficiency, an artificial neural network is combined with an efficient spectral domain method. An efficient analysis tool for a silicon micromachined H-slot coupled antenna is developed by combining the transmission line models of the H-slot and an aperture coupled antenna. The experimental results are compared with the theory showing good agreement.</p><p>The analysis and design of a microwave amplifier based on non-resonant slot matching is carried out. It is seen that the designed slot matched amplifier has decreased layout size, improved gain and noise figure characteristics compared to a stub matched amplifier. An efficient method for the analysis of non-resonant slots is compared with other approaches showing good agreement. This points to the fact that non-resonant slot matched circuits can be designed with the same speed and efficiency as we design the traditional stub based matching circuits.</p><p>To address the problem of bandwidth and performance of reflect-arrays we propose a dielectric resonator antenna with slotline stubs. As a preliminary step we design a dielectric resonator antenna with slotline feed and the experimental results are compared with those of a commercial CAD tool. Design and analysis of 3D interconnects based on non-radiative dielectric waveguides is carried out. At millimeterwave, these interconnects are useful for hybrid and multilayer integration techniques.</p>

Thesis (Ph.D. (English))--North-West University, Potchefstroom Campus, 2007.

Thesis (Ph.D. (Social Work))--North-West University, Potchefstroom Campus, 2009.

The purpose of this study is to create a performer's guide for three separate pieces written by David Sampson. The first piece, Breakaway, is written for two trumpets and electronic accompaniment. The second piece is entitled Passage, and is written for muted flugelhorn and viola. The final piece for examination is the Sonata for trumpet entitled Triptych, a commission from the International Trumpet Guild in 1991. Although the number of compositions for trumpet has increased in the twentieth and twenty-first centuries, guides for the performer regarding pieces with unique instrumentation and internationally commissioned works extremely limited. Included in this study is an examination of the specific challenges found in Breakaway, Passage, and Triptych, with detailed consideration regarding the methods with which to execute the unique performance elements of each composition. In addition, the information found in this study will expand the number of twentieth and twenty-first century trumpet works that have been investigated in a formal research capacity.

Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. The unit cell of the active reflect-array consists of an amplifying active reflect-antenna designed using a novel dual polarized microstrip-T coupled patch antenna. Two modelling approaches are proposed for the active reflect-antenna and the modelling methods are compared with the experiments. A computationally efficient analysis of an H-slot in the ground plane of a microstripline is carried out using a transmission line model. To improve the accuracy in the resonant region of the H-slot and retaining the computational efficiency, an artificial neural network is combined with an efficient spectral domain method. An efficient analysis tool for a silicon micromachined H-slot coupled antenna is developed by combining the transmission line models of the H-slot and an aperture coupled antenna. The experimental results are compared with the theory showing good agreement. The analysis and design of a microwave amplifier based on non-resonant slot matching is carried out. It is seen that the designed slot matched amplifier has decreased layout size, improved gain and noise figure characteristics compared to a stub matched amplifier. An efficient method for the analysis of non-resonant slots is compared with other approaches showing good agreement. This points to the fact that non-resonant slot matched circuits can be designed with the same speed and efficiency as we design the traditional stub based matching circuits. To address the problem of bandwidth and performance of reflect-arrays we propose a dielectric resonator antenna with slotline stubs. As a preliminary step we design a dielectric resonator antenna with slotline feed and the experimental results are compared with those of a commercial CAD tool. Design and analysis of 3D interconnects based on non-radiative dielectric waveguides is carried out. At millimeterwave, these interconnects are useful for hybrid and multilayer integration techniques.