This diploma thesis deals with the structural design and production of a oscillating head for surface welding of a protective layer of Inconel® 625 superalloy on membrane walls. The design is preceded by a research for possible variants of the solution. Of the two designs, one was successfully manufactured and assembled, and incentives for future improvements were set. For easy optimization and testing of the device, an oscillating motion program was created in the LinMoT Talk 6.9 software. The production costs for the manufactured equipment were then calculated and the recommended selling price was determined, based on a general calculation formula. The result of the project is a functional device, a proposal for its control and a technical - economic evaluation of the production process.

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Denna rapport ämnar undersöka de vanligast förekommande typerna av teknologier för vågkraftverk (eng. Wave Energy Converter, WEC) teknologier för att jämföra de olika konceptens förmåga att absorbera vågenergi. Koncept som undersöks är punktabsorbatorer och oscillerande vattenkolumner. I denna rapport används de vanligt använda engelska översättningarna point absorber och oscillating water column (OWC). Beräkningar görs för de olika koncepten i liknande vågförhållanden för att kunna jämföra den energi som kan utvinnas. I rapporten sker beräkningar under optimala vågförhållanden. Vågorna antas vara linjära och vågkraftverken antas vara i fas med vågens svängningsrörelse. Den vågdata som använts är uppmätt utanför Belmullet i Irland. Beräkningar görs på vågor med en signifikant våghöjd på 1,25 m och en periodtid på 7,5 s. Det görs även beräkningar på den största uppmätta förekommande vågen. I huvudsak används effektberäkningar enligt en modell som Kjell Budal. Syftet är att grafiskt och numeriskt jämföra den teoretiska och faktiska maxeffekt som kan utvinnas ur respektive våg. Resultatet från undersökningen visar att den största bidragande faktorn till en hög energiutvinning beror på bojens volym. Volymen måste anpassas för de vågförhållanden som finns där bojen ska placeras.Vid beräkningar av en OWC med tvärsnittsarea på 19 m2 visar det sig att den effekt som kan utvinnas av en luftkammare med tillhörande turbin är ungefär 10 kW, 1/30 av de 300kW som kan utvinnas av en point absorber. En OWC består dock sällan utav en ensam luftkammare utan ofta i en array med ett flertal luftkammare med separata turbiner för att öka effekten. / This report intends to examine the most common types of wave energy converter technologies to compare the different concepts' ability to absorb wave energy. Concepts being investigated are point absorbers and oscillating water columns (OWC). Calculations are made for the different concepts in the same wave conditions to be able to compare the energy that can be extracted. In the report, calculations are made under optimal wave conditions. The waves are assumed to be linear and the wave energy converter is assumed to be in phase with the oscillating motion of the wave. The wave data used is measured outside Belmullet in Ireland. Calculations are made on waves with a significant wave height of 1.25 m and a period time of 7.5 s. Calculations are also made on the largest measured wave present. In essence, power calculations are used according to a model developed by Kjell Budal and with the help of this be able to graphically and numerically compare the theoretical and actual maximum power that can be extracted from each scale. The results from the survey show that the largest contributing factor to high energy recovery is due to the volume of the buoy. The volume must be adapted to the wave conditions that exist where the buoy is to be placed.When calculating an OWC with a cross sectional area of 19 m2, it turns out that the power that can be extracted from an air chamber with an associated turbine is approximately 10 kW, 1/30 of the 300 kW that can be extracted by one point absorber. However, an OWC rarely consists of a single air chamber but often in a construction with several air chambers with separate turbines to increase the power.

Thesis (MMus (Music))--University of Stellenbosch, 2009 / Violin vibrato is the action by which a violinist periodically changes the frequency of a sustained note by moving the finger on the string, rapidly backwards and forwards. If it is artistically applied, it adds life, character and warmth to an otherwise dull sounding note. Although it has been used since the sixteenth century, very little research has been done on the reason why humankind would experience such periodic fluctuations as an object of beauty in violin performance. In answering the question, this study explores a variety of angles of approach in order to understand the phenomenon in its full context. The history, development and geographical origin of the technique are firstly discussed in a diachronic fashion and provide the background for the subsequent synchronic research on the physical nature of violin sound and violin vibrato. The vibrato rates and widths of four virtuosi are measured and compared to highlight the differences and individuality which are argued to be a contributing factor to the perception of beauty of the technique. It is established in the final chapter that the brain is stimulated more by sounds with periodic changes than those that are presented in the steady-state which cast some light on why vibrato may be experienced as an appreciated addition to sound. The thesis aims to present a unique view on the possibilities of interdisciplinary research of the phenomenon of violin vibrato. It further aims to present the research findings in a concise, logical, and systematic manner that could be of interest to both musician and scientist.

Fluid structure interactions in the presence of a free surface includes complex phenomena, such as slamming, air entrainment, transient loads, complex free surface profiles and turbulence. Hence, an appropriate and efficient numerical method is required to deal with these type of problems (efficient both in problem setup and numerical solution). Eulerian mesh-based methods can be used to solve different types of problems, however they have difficulties in problems involving moving boundaries and discontinuities (e.g. fluid structure interactions in the presence of a free surface). Smoothed Particle Hydrodynamics (SPH) is a mesh-less Lagrangian particle method, ideal for solving problems with large deformation and fragmentation such as complex free surface flows. The SPH method was originally invented to study astrophysical applications and requires modifications in order to be applied for hydrodynamic applications. Applying solid boundary conditions for hydrodynamic applications in SPH is a key difference to the original SPH developed for astrophysics. There are several methods available in literature to apply solid boundaries in SPH. In this research, an accurate solid boundary condition is used to calculate the pressure at the boundary particles based on the surrounding fluid particles. The two main methods to calculate the pressure in the SPH method are the weakly compressible SPH (WCSPH) and the incompressible SPH (ISPH) approaches. The WCSPH uses the equation of state while ISPH solves Poisson's equation to determine the pressure. In this dissertation, an explicit incompressible SPH (ISPH) method is used to study nonlinear free surface applications. In the explicit ISPH method, Poisson's equation is explicitly solved to calculate the pressure within a projection based algorithm. This method does not require solving a set of algebraic equations for pressure at each time step unlike the implicit method. Here, an accurate boundary condition along with an accurate source term for Poisson's equation is used within the explicit method. Also, the sub-particle turbulent calculation is applied to the explicit ISPH method (which handles large-scale turbulent structures implicitly) in order to calculate the flow field quantities and consequently forces on the device more accurately. The SPH method is typically computationally more expensive than Eulerian-based CFD methods. Therefore, parallelization methods are required to improve the performance of the method, especially for 3D simulations. In this dissertation, two novel parallel schemes are developed based on Open Multi Processing (OpenMP) and Message Passing Interface (MPI) standards. The explicit ISPH approach is an advantage for parallel computing but our proposed method could also be applied to the WCSPH or implicit ISPH. The proposed SPH model is used to simulate and analyze several nonlinear free surface problems. First, the proposed explicit ISPH method is used to simulate a transient wave overtopping on a horizontal deck. Second, a wave impacting on a scaled oscillating wave surge converter (OWSC) is simulated and studied. Third, the performance and accuracy of the code is tested for a dam-break impacting on tall and short structures. Forth, the hydrodynamic loads from the spar of a scaled self-reacting point absorber wave energy converter (WEC) design is studied. Finally, a comprehensive set of landslide generated waves are modeled and analyzed and a new technique is proposed to calculate the motion of a slide on an inclined ramp implicitly without using a prescribed motion. / Graduate

Any periodic signal can be decomposed into a sum of oscillating functions. Traditionally, cosine and sine segments have been used to represent a single period of the periodic signal (Fourier Series). In more general cases, each of these functions can be represented by a set of spectral parameters such as its amplitude, frequency, phase, and the variability of its instantaneous spectral components. The accuracy of these parameters depends on several processing variables such as resolution, noise level, and bias of the algorithm used. This thesis presents some background of existing frequency estimation techniques and proposes a new technique for estimating the instantaneous frequency of signals using short sinusoid-like basis functions. Furthermore, it also shows that the proposed algorithm can be implemented in a popular embedded DSPmicroprocessor for practical use. This algorithm can also be implemented using more complex features on more resourceful processing processors in order to improve estimation accuracy

Au cours des vingt dernières années, les facettes céramiques sont devenues une solution esthétique très répandue en raison de leur conception de préparation peu invasive, de leurs propriétés biocompatibles, de leur similitude avec la couleur naturelle des dents, ainsi que de leur translucidité et de leur résistance mécanique aux forces occlusales et à l’usure [1]. La définition des facettes dentaires est celle de « coquilles » très minces, faites sur mesure de matériaux de la couleur de la dent, conçues pour recouvrir la face avant ou la face supérieure des dents afin d' en améliorer l'esthétique et/ou corriger des problèmes occlusaux. Elles sont collées aux dents et pourront en modifier la couleur la forme, et le volume [2].Elles trouvent ainsi de multiples indications à différents endroits sur les arcades dentaires sur les faces vestibulaires des dents antérieures ou plus récemment pour restaurer les surfaces occlusales corriger une occlusion déficiente [3, 4].Ces restaurations modernes se sont développées avec l'arrivée de nouveaux matériaux de reconstructions et de collages, ainsi que de nouveaux modes de conception et fabrication répondant à des exigences de simplicité, de rapidité et de précision.Pour préparer la dent à recevoir une facette, l'oscillation d’inserts ultrasonores a été proposée pour améliorer la finition des lignes marginales et optimiser l’état de surface [5].Pour leur fabrication, outre les méthodes prothétiques classiques, la CFAO (conception assistée par ordinateur - fabrication assistée par ordinateur) au développement exponentiel [6, 7 permet de réaliser une prothèse restauratrice en une seule visite en clinique avec la précision que permettent l’optique (empreintes) et la robotique (fabrication de la facette) ;[8-14]. D’autre part l’apparition de nouvelles céramiques a permis d'améliorer leur esthétique et d'augmenter leur durabilité, qu'elle soit antérieure ou occlusale.Notre première étude portait sur de nouveaux outils permettant d'optimiser la procédure de préparation des facettes. L'utilisation ou non d‘inserts oscillants sur la qualité de l'état de surface de la dent traitées pour une telle préparation. Cette question importante et récurrente, [15] pose le problème de la qualité de l'état de surface destiné à recevoir par collage une pellicule de céramique de faible épaisseur. La pérennité de ce type de prothèse dépend essentiellement du collage avec les tissus dentinaires préparés [16, 17]. La littérature, atteste d’une meilleure qualité de collage entre des surfaces dentaires rugueuses et les matériaux de restauration [18-22]. Toutefois, une question se pose concernant la qualité de cette rugosité lorsque / The first chapter of the thesis relieved the dentists from thinking a lot about the produced roughness regardless to the preparation tool. The roughness is a critical factor to the stability, to the retention, and eventually to the success of the ceramic veneers especially for the esthetic anterior veneers. This will speed up the procedure of achieving a fast treatment for the patients with the CAD-CAM systems. For the upcoming steps, an investigation is recommended to estimate the amount of the inquired roughness to achieve the minimum necessary adhesion value for the retention of the ceramic veneers, and vice versa, another investigation to evaluate the capability of the preparation tools in transferring the same roughness from the preparation tool grains to the target surface (dentin or enamel).152The second study had filled the gap of how to evaluate the IOS systems regardless to the recent common criteria, and the thesis created a novel measure (noise) to be used. The study asks the dentists to pay attention to other criteria to consider when buying an IOS system regardless to the criteria that already exists and had been directed by the producing companies. The thesis states that the noise increases when the direction of the IOS is changed. More attention should be paid at the transitional lines between the scanned surfaces while designing the digital model. An enhancement is demanded to compensate for (or if possible, to eliminate) this noise.

Este trabalho apresenta a calibração e o desenvolvimento de um tanque de reaeração, equipamento que gera turbulência com intensidade controlável por meio de grade oscilante. Foram realizadas adequações ao projeto inicial de construção do tanque, idealizado por ROMA, onde se buscou o equilíbrio e as limitações de funcionamento para que, em futuros trabalhos, o tanque possa ser utilizado sob condições adequadas sem a presença de \"ruídos\" que venham a interferir nos resultados. A calibração do tanque foi realizada levantando-se o coeficiente de reaeração \'K IND.2\' para dois tipos de grades, 256 malhas/\'M POT.2\' e 1024 malhas/\'M POT.2\' constituídas por barras de seção medindo 10 x 10 mm, em diversas freqüências de oscilações sob condições controladas de temperatura e umidade relativa do ar. Com auxílio de um medidor eletroquímico de oxigênio dissolvido e de um contador de rotação, pôde-se acompanhar a reoxigenação da água e avaliar a freqüência de oscilação das grades. A desaeração da massa de água, necessária para a calibração do tanque, foi promovida por Stripping provocado por cavitação forçada à temperatura ambiente com injeção de nitrogênio. A taxa de reaeração \'K IND.2\' foi calculada por medidas da variação do oxigênio dissolvido em função do tempo provocada por agitação mecânica para determinada freqüência de oscilação da grade. Os resultados obtidos forneceram as curvas de reaeração em função da freqüência de oscilação e do tipo de grade utilizada em cada ensaio que, através do uso de planilha eletrônica, determinaram-se os valores de concentração de saturação (Cs) e coeficiente de reoxigenação (\'K IND.2\') com o uso de regressão não linear. / This work presents a reaeration tank development and its calibration, equipment that generates controlled intensity turbulence produced by oscillating grid. An adaptation on the original design idealized by Roma was made improving the equilibrium of the oscillating grid mechanism and defining the limits of functionality of the device. These are important aspects for future research on experimental turbulence generation since that the use of equipment free of undesirable disturbing noise are of fundamental importance. Tank calibration was obtained through the evaluation of the reaeration coefficient \'K IND.2\' using two types of oscillating grids, 256 and 1024 meshes/\'M POT.2\', constructed with 10 x 10 \'MM POT.2\' square section bars. Experimental runs were conducted under controlled conditions of air temperature and humidity, for several oscillating frequencies for each grid. The necessary water mass desaeration was obtained by ambient temperature stripping, induced by forced cavitation and nitrogen injection. Reaeration coefficients were calculated from data obtained from dissolved oxygen concentration measurements as function of time for each grid size and oscillating frequency combination. As results, reaeration curves with reaeration coefficients as function of oscillating frequency and grid type are presented.

O estudo e observação de Sistemas Químicos Oscilantes vêm se destacando como importante campo de pesquisa da ciência química contemporânea. Tais sistemas têm como comportamento notório principal a variação periódica da concentração de um intermediário de reação química. Sua compreensão vem estimulando debates que transcendem o escopo químico e estabelecem relações com outras disciplinas científicas, e mais marcadamente, o estudo de sistemas complexos em geral. O ensino de sistemas químicos oscilantes, em específico, e de sistemas complexos, em geral, se apresenta na atualidade como desafio necessário e estimulante. Neste trabalho optou-se por tentar contribuir neste esforço, utilizando-se da noção de obstáculos epistemológicos inicialmente estabelecida pelo filósofo francês Gastón Bachelard. O conceito de obstáculos epistemológicos apresentou-se nas últimas décadas como importante ferramenta na abordagem das relações de ensino-aprendizagem de conceitos das ciências contemporâneas. Existem diferentes tipos de obstáculos epistemológicos, entre eles: experiência primeira, conhecimento geral, obstáculo verbal, conhecimento unitário e pragmático e obstáculo animista. Neste trabalho surge a proposta de utilizar a noção de obstáculo epistemológico voltada ao ensino de conceitos da complexidade pertinentes aos Sistemas Químicos Oscilantes. Foram analisadas as presenças de obstáculos epistemológicos em textos didáticos de ensino de sistemas químicos oscilantes. Os textos didáticos escolhidos foram artigos científicos da área de ensino de química voltados ao ensino de sistemas químicos oscilantes, livros didáticos usados em cursos de graduação e livros de divulgação científica. Foram analisados os conteúdos integrais de sete artigos científicos da área de ensino de química voltados ao tema reações químicas oscilantes. Foram também analisadas as seções referentes a reações químicas oscilantes de quatro livros didáticos utilizados em cursos de graduação da USP devotadas ao ensino de sistemas caóticos. Foram também analisadas as seções referentes a reações químicas oscilantes de quatro livros de divulgação científica que abordaram o tema sistemas químicos oscilantes. Foram encontrados grande número de obstáculos da experiência primeira e obstáculos animistas em livros didáticos e um grande número de obstáculos verbais em livros de divulgação científica. Todos os tipos de obstáculos epistemológicos listados foram identificados ao menos uma vez em algum dos textos. Demonstrou-se a viabilidade de aplicação do conceito de obstáculos epistemológicos em textos didáticos de ensino de sistemas químicos oscilantes. / The study and observation of Oscillating Chemical Systems have been highlighted as an important research field of chemical science contemporary. Such systems are notorious behavior as the main periodic variation of the concentration of an intermediate chemical reaction. Your understanding is stimulating debates that transcend the scope of chemical and establish relationships with other scientific disciplines, and most notably, the study of complex systems in general. The teaching of chemical oscillating systems, in particular, and complex systems in general, is presented nowadays as necessary and stimulating challenge. In this work it was decided to try to contribute in this effort, using the notion of epistemological obstacles initially established by the philosopher Gaston Bachelard. The concept of epistemological obstacle presented itself in recent decades as an important tool in addressing the relationships of teaching and learning of contemporary science concepts. There are different kinds of epistemological obstacles, among them: first experience, geral knowledge, verbal obstacle, pragmatic and unitary knowledge and animist obstacle . This work comes propose to use the notion of epistemological obstacle to teach the complexity of concepts relevant to oscillating chemical system .We analyzed the presence of epistemological obstacles in textbooks that have teaching oscillating chemical systems. The selected texts were scientific articles in the area of chemical education aimed at teaching oscillating chemical systems, books used in undergraduate and some popular science books. We analyzed the entire contents of seven papers in the area of chemical education geared to the theme oscillating chemical reactions. We also analyzed the sections pertaining to oscillating chemical reactions of four textbooks used in undergraduate courses devoted to teaching the chaotic systems at USP . We also analyzed the sections pertaining to oscillating chemical reactions of four popular science books that addressed the issue of oscillating chemical systems. We found many first experiences and animists obstacles in textbooks and a large number of verbal obstacles in popular science books. All kinds of epistemological obstacles identified were listed at least once at some of the texts. The results confirm the feasibility of applying the concept of epistemological obstacles in textbooks teaching oscillating chemical systems.

Este trabalho representa o início de uma série de pesquisas que visam o estudo da turbulência e de sua relação com processos de mistura e trocas gasosas entre ar e água, através de experimentos com grades oscilantes. Seu objetivo foi o projeto e a construção de um tanque de grade oscilante, equipamento que gera turbulência com intensidade controlável. Após a construção do tanque, experimentos para medições de velocidade turbulenta foram feitos, com uso de uma técnica de velocimetria a laser. Uma grade de 9x9 barras foi usada na agitação do fluido, com uma amplitude de oscilação de 3 cm, para 4 diferentes freqüências de oscilação. Adquiriu-se 9600 imagens do movimento do fluido, em 6 regiões do tanque, para a obtenção dos campos de velocidade turbulenta, calculados através do software Visiflow e de um programa computacional desenvolvido neste trabalho. Os gráficos criados a partir dos campos possibilitaram a observação do decaimento espacial da turbulência e da região de sua produção. Os campos médios de velocidade mostraram-se bem inferiores aos campos instantâneos, indicando a existência de baixo escoamento médio do fluido. As condições de isotropia e a homogeneidade espacial da turbulência são mais aproximadas à medida que se afasta da grade. A intensidade turbulenta produzida é diretamente relacionada com a freqüência de oscilação. O número de imagens para a obtenção de uma média representativa da velocidade turbulenta neste equipamento parece ser dependente da freqüência de oscilação da grade. Isto aponta para a necessidade de estabelecer corretamente as condições para os cálculos estatísticos em escoamentos turbulentos / This work presents the project and construction of a tank with an oscillating grid, equipment which provides for the experimental studies of turbulence and its relation to mixing processes and gas transfer across fluid interface. Experiments were carried out with the use of digital particle image velocimetry technique, to investigate the properties of the produced turbulence. A grid made of 9x9 square bars was used to stir the water, with a stroke of 3 cm and 4 different oscillation frequencies. A number of 9600 images were acquired, in 6 regions of the tank, for the generation of the turbulent velocity fields through the software Visiflow and a computational program developed in this work. The results showed that the current equipment, with a new concept for the grid oscillation system, can be conveniently useful for studies in this research field. Average velocity fields appeared to be considerably smaller than the instantaneous velocity fields, which leads to the existence of nearly-stationary turbulence in the water volume. Nearly-isotropic turbulence and spatial homogeneity were approximate as the measurements distanced from the grid. The turbulent intensity was directly dependent on the oscillation frequency. The spatial decay of the turbulence and the region near the grid where it is produced could also be observed. The number of images necessary for the calculus of reliable root-mean-square turbulent velocities seems to be dependent on the oscillation frequency of the grid. It results in the necessity of establishing correct statistical analysis of turbulent flows