Arctic Ocean monitoring with near-real-time data transfer is urgently needed. The harsh and remote conditions constraining year-round observation sites present significant logistical challenges and energy needs for sustained Arctic observations. The Arctic project group is attempting to design a mechanical structure to harvest energy from low-speed current in the Arctic Ocean. An Arctic energy harvesting system that consists of a transverse flux generator, boosted by a nozzle-diffuser-duct, and an American multiblade turbine that drives the generator, are designed in this study. The transverse flux generator is then optimized based on its design parameters and the optimization successfully improves the torque performance of the generator while maintaining the largest power output. The American turbine fits the extreme low-speed current condition (<0.2m/s) well and could support the rotation of the generator. Finally, the article compares the energy harvesting system is compared with the existing ones in the market and demonstrates its superior performance. / Master of Science / Arctic area has great potential and it is beneficial to monitor and do research in the Arctic area. The continuous energy could be a problem. The challenging and isolated conditions that limit the establishment of year-round observation stations pose significant logistical hurdles and energy requirements for continuous Arctic data collection. To address this, the Arctic project team is endeavoring to create a mechanical structure capable of harnessing energy from low-speed currents in the Arctic Ocean.

Fan system efficiency for modern aircraft engine design is increasing to the point that bypass duct geometry is becoming a significant contributor and could ultimately become a limiting factor. To investigate this, a number of methods are available to provide qualitative and quantitative analysis of the flow around the loss mechanisms present in the duct. Particle image velocimetry (PIV) is a strong candidate among experimental techniques to address this challenge. Its use has been documented in many other locations within the engine and it can provide high spatial resolution data over large fields of view. In this work it is shown that these characteristics allow the PIV user to reduce the spatial sampling error associated with sparsely spaced point measurements in a large measurement region with high order gradients and small spatial scale flow phenomena. A synthetic flow featuring such attributes was generated by computational fluid dynamics (CFD) and was sampled by a virtual PIV system and a virtual generic point measurement system. The PIV sampling technique estimated the average integrated velocity field about five times more accurately than the point measurement sampling due to the large errors that existed between each point measurement location. Despite its advantages, implementation of PIV can be a significant challenge, especially for internal measurement where optical access is limited. To reduce the time and cost associated with iterating through experiment designs, a software package was developed which incorporates basic optics principles and fundamental PIV relationships, and calculates experimental output parameters of interest such as camera field of view and the amount of scattered light which reaches the camera sensor. The program can be used to judge the likelihood of success of a proposed PIV experiment design by comparing the output parameters with those calculated from benchmark experiments. The primary experiment in this work focused on the Pratt and Whitney Canada JT15D-1 aft support strut wake structure in the bypass duct and was comprised of three parts: a simulated engine environment was created to provide a proof of concept of the PIV experiment design; the PIV experiment was repeated in the full scale engine at four fan speeds ranging from engine idle up to 80% of the maximum corrected fan speed; and, finally, a CFD simulation was performed with simplifying assumptions to provide insight and perspective into the formation of the wake structures observed in the PIV data. Both computational and experimental results illustrate a non-uniform wake structure downstream of the support strut and support the hypothesis that the junction of the strut and the engine core wall is creating a separate wake structure from that created by the strut main body. The PIV data also shows that the wake structure moves in the circumferential direction at higher fan speeds, possibly due to bulk swirl present in the engine or a pressure differential created by the support strut. The experiment highlights the advantages of using PIV, but also illustrates a number of the implementation challenges present, most notably, those associated with consistently providing a sufficient number of seeding particles in the measurement region. Also, the experiment is the first to the author's knowledge to document the use of PIV in a full scale turbofan engine bypass duct. / Master of Science

This work presents the design and analysis of two Litz wire transformers for a 500 kHz, 18 kW input­parallel output­series partial power processing converter (IPOS PPP). Because the two power paths in the IPOS PPP operate as “dc transformers” (DCX), both transformers are designed with the goal of leakage inductance minimization in order to reduce gain variation around the resonant frequency. The selected winding topology with the lowest leakage inductance results in an impedance mismatch among parallel secondaries used in the majority power path transformer, resulting in poor current sharing. In order to balance the goals of leakage inductance minimization and even current sharing, a new winding technique called “intra­leaving” is presented which reduces current sharing error from 50%, to 5%. A design rule for “intra­leaving” is also established which extends the winding method to different winding configurations and higher numbers of parallel winding. A novel cooling duct designed with computational fluid dynamics is used for transformer thermal management. The cooling duct uses two 30 mm 7.7 CFM fans to cool the transformer winding and achieves a small height of 43 mm and only 6.8 W power consumption. Using the cooling duct, 106 °C peak winding temperature and 76 °C peak core temperature is achieved at 15 kW load, an ∼ 8% reduction compared to using a conventional 120 mm fan 41 CFM fan. The two transformers with the cooling system achieve 635 W/in3 power density, 1U height compliance, and 99.4% peak efficiency. / M.S. / As society moves towards the electric grid of the future, there have been increased calls for the research and development of resonant power converters due to their high efficiency, high power density, and low electromagnetic interference. The high frequency transformer is one of the main components of the resonant converter system as it contributes substantially to the converters volume, power loss, and thermal management risks. This work seeks to address the trade­offs between leakage inductance minimization and transformer current sharing and proposes a winding method called “intra­leaving” which achieves both. Using “intra­leaving” current sharing error was reduced from 50%, to 5%. Operating transformers at high frequency reduces their volume in accordance with Faraday’s law but also increases thermal risks due to decreased core surface area, higher winding fill factor, and higher loss per unit volume. A novel cooling duct designed using computational fluid dynamics is presented using two 30 mm 7.7 CFM fans and achieves a small height of 43 mm and only 6.8 W power consumption. Using the cooling duct, 106 °C peak winding temperature and 76 °C peak core temperature is achieved at 15 kW load, an ∼ 8% reduction compared to using a conventional 120 mm fan 41 CFM fan. The transformers with the cooling system designed in this work achieve 635 W/in³ power density, 1U height compliance, and 99.4% peak efficiency.

Gas turbines for military applications, when operating in harsh environments like deserts often encounter unexpected operation faults. Such performance deterioration of the gas turbine decreases the mission readiness of the Air Force and simultaneously increases the maintenance costs. Some of the major factors responsible for the reduced performance are ingestion of debris during take off and landing, distorted intake flows during low altitude maneuvers, and hot gas ingestion during artillery firing. The focus of this thesis is to study ingestion of debris; specifically sand. The region of interest being the internal cooling ribbed duct of the turbine blade. The presence of serpentine passages and strong localized cross flow components makes this region prone to deposition, erosion, and corrosion (DEC) by sand particles. A Lagrangian particle tracking technique was implemented in a generalized coordinate multi-block Navier-Stokes solver in a distributed parallel framework. The developed algorithm was validated by comparing the computed particle statistics for 28 microns lycopodium, 50 microns glass, and 70 microns copper with available data [2] for a turbulent channel flow at Ret=180. Computations were performed for a particle-laden turbulent flow through a stationary ribbed square duct (rib pitch / rib height = 10, rib height / hydraulic diameter = 0.1) using an Eulerian-Lagrangian framework. Particle sizes of 10, 50, and 100 microns with response times (normalized by friction velocity and hydraulic diameter) of 0.06875, 1.71875, and 6.875 respectively are considered. The calculations are performed for a nominal bulk Reynolds number of 20,000 under fully developed conditions. The carrier phase was solved using Large Eddy Simulation (LES) with Dynamic Smagorinsky Model [1]. Due to low volume fraction of the particles, one-way fluid-particle coupling was assumed. It is found that at any given instant in time about 40% of the total number of 10 micron particles are concentrated in the vicinity (within 0.05 Dh) of the duct surfaces, compared to 26% of the 50 and 100 micron particles. The 10 micron particles are more sensitive to the flow features and are prone to preferential concentration more so than the larger particles. At the side walls of the duct, the 10 micron particles exhibit a high potential to erode the region in the vicinity of the rib due to secondary flow impingement. The larger particles are more prone to eroding the area between the ribs and towards the center of the duct. At the ribbed walls, while the 10 micron particles exhibit a fairly uniform propensity for erosion, the 100 micron particles show a much higher tendency to erode the surface in the vicinity of the reattachment region. The rib face facing the flow is by far the most susceptible to erosion and deposition for all particle sizes. While the top of the rib does not exhibit a large propensity to be eroded, the back of the rib is as susceptible as the other duct surfaces because of particles which are entrained into the recirculation zone behind the rib. / Master of Science

Introdução: A radioiodoterapia (RIT) constitui tratamento consagrado para carcinomas diferenciados de tireoide, sendo amplamente utilizada em todo o mundo, tendo-se em vista a incidência crescente desse tipo de neoplasia maligna. Embora efeitos adversos graves sejam infrequentes, são descritas complicações como xerostomia, sialoadenite e disfagia. O acometimento de olhos e anexos é pouco discutido, sendo relatadas xeroftalmia, ceratoconjuntivite e obstrução de vias lacrimais (OVL), notadamente após altas doses cumulativas do radiofármaco. A incidência de OVL e a eventual relação com outros sintomas oculares ou extraoculares não são bem estabelecidas. Neste estudo, buscamos determinar a frequência de obstrução de vias lacrimais (OVL) em pacientes submetidos à RIT, a existência de fatores preditores de OVL e a relação entre alterações de superfície ocular, xerostomia e alterações da mucosa nasal. Métodos: Foram avaliados pacientes com diagnóstico de carcinoma diferenciado de tireoide submetidos à RIT (Grupo 1) e não submetidos à RIT (Grupo 2) no período pré-operatório, pós-operatório e no 2º, 4º, 6º e 12º mês pós-cirurgia ou pós-RIT. Os pacientes foram submetidos a avaliações da superfície ocular e do filme lacrimal, sondagem e irrigação de vias lacrimais, quantificação da produção salivar e endoscopia nasal. As avaliações subjetivas de sintomas oculares, nasais e de xerostomia foram realizadas, respectivamente, por meio dos questionários OSDI, NOSE e Xerostomia Inventory. Resultados: O Grupo 1 (n=44, 88 olhos) apresentou 3 pacientes (04 olhos) com OVL, o que corresponde à incidência de 4,55% (4 eventos em 88 olhos) ou 6,8% (3 casos em 44 pacientes). O Grupo 2 (n=43, 86 olhos) não apresentou nenhum caso de OVL, fato que impossibilitou o cálculo da razão de chances (odds ratio). A avaliação objetiva da superfície ocular não apresentou diferenças significantes entre os grupos. Por outro lado, a avaliação endoscópica nasal revelou maior palidez de mucosa no Grupo 1 no 2º mês (OR: 3,61; IC 95%: 1,44-9,09; p < 0,01), 4º mês (OR: 4,00; IC 95%: 1,48-10,79; p < 0,01) e 12º mês de seguimento pós-RIT (OR: 3,24; IC 95%: 1,14-9,22; p=0,03), com piora do escore de aparência endoscópica quanto a edema, a pólipos e à secreção no 6º mês de seguimento pós-RIT, em comparação à avaliação pré-operatória (p < 0,01). Os resultados do questionário OSDI demonstraram piora do escore no Grupo 1 no 2º mês (p < 0,01), 4º mês (p < 0,01), 6º mês (p < 0,01) e 12º mês (p < 0,01) de seguimento pós-RIT em comparação à avaliação inicial pré-operatória. A avaliação pelo questionário NOSE demonstrou piora dos sintomas nasais no Grupo 1 no 2º mês (p=0,02) e no 4º mês de seguimento pós-RIT (p < 0,01), em comparação aos sintomas pré-operatórios. A avaliação da xerostomia demonstrou piora dos sintomas no Grupo 1 em relação à avaliação pré-operatória e no 2º mês (p < 0,01), 4º mês (p < 0,01), 6º mês (p < 0,01) e 12º mês (p=0,01) de seguimento pós-RIT, bem como diminuição objetiva da produção salivar até o 12º mês pós-RIT (p < 0,01). Conclusões: Embora em pequeno número, o presente estudo demonstrou aparecimento de casos de obstrução lacrimal, mesmo que assintomáticas, nos primeiros 12 meses após-RIT. Não foi possível estabelecer relação da OVL com eventuais fatores preditores. Entretanto, demonstrou-se piora subjetiva da xerostomia, da xeroftalmia, dos sintomas nasais e significativa alteração da mucosa nasal nos pacientes do Grupo 1 / Introduction: Radioiodine therapy (RIT) is an established treatment for differentiated thyroid carcinomas and is widely used throughout the world, given the increasing incidence of this malignancy. Although serious adverse effects are infrequent, complications such as dry mouth, sialadenitis and dysphagia have been described. The involvement of the eyes and adnexa is not commonly discussed, despite dry eye, keratoconjunctivitis and lacrimal system obstruction (LSO) being reported, especially after high cumulative doses of this radiopharmaceutical. The incidence of LSO and any relationship with other ocular or extraocular symptoms are not well established. The study objectives were to determine the frequency of lacrimal system obstruction (LSO) in patients undergoing RIT, the existence of predictive factors of LSO and the relationship between ocular surface changes, xerostomia and changes in nasal mucosa. Patients and Methods: Patients with differentiated thyroid carcinoma undergoing (Group 1) and not undergoing (Group 2) RIT were evaluated in the preoperative and postoperative periods and 2, 4, 6 and 12 months post-surgery or post-RIT. Patients underwent ocular surface and tear film evaluation, lacrimal system probing and irrigation, quantification of salivary production and nasal endoscopy. The subjective evaluations of ocular symptoms, nasal symptons and xerostomia were done, respectively, through the OSDI, NOSE and Xerostomia Inventory questionnaires. Results: Group 1 (n = 44, 88 Eyes) had 3 patients (4 eyes) with LSO, corresponding to an incidence of 4.55% (4 events in 88 eyes) or 6.8% (3 cases in 44 patients). Group 2 (n = 43.86 eyes) did not present any cases of LSO, that makes it impossible to calculate the odds ratio. Objective assessment of ocular surface did not show significant differences between groups. On the other hand, nasal endoscopy revealed larger mucosa pallor in Group 1 in the 2nd month (OR: 3.61; 95% CI: 1.44 to 9.09; p < 0.01), 4th month (OR: 4.00; 95% CI: 1.48 to 10.79; p < 0.01) and 12th month after RIT (OR: 3.24; 95% CI: 1.14 to 9.22; p = 0.03), with worsening of the endoscopic appearance score in the 6th month after RIT, compared to the preoperative evaluation (p < 0.01). The results of the questionnaires showed worsening OSDI score in Group 1 at 2nd month (p < 0.01), 4th month (p < 0.01) and 6 months (p <0.01) and 12 months (p < 0, 01) post RIT as compared to the preoperative baseline. The evaluation by the NOSE questionnaire showed worsening of nasal symptoms in Group 1 in the 2nd month (p=0.02) and 4th month (p < 0.01) after RIT, compared to preoperative data. The evaluation of xerostomia showed worsening of symptoms in Group 1 compared to preoperative assessment at 2nd month (p < 0.01), 4th month (p < 0.01), 6th month (p < 0.01) and 12 months (p = 0.01) after RIT. Objective decreased saliva production was observed until the 12th month after RIT (p < 0.01). Conclusions: Although in small number, the present study demonstrated the emergence of cases of lacrimal obstruction, even if asymptomatic, in the first 12 months after RIT. It was not possible to establish a relationship between LSO and predictive factors. However, it was demonstrated subjective worsening of xerostomia, xerophthalmia and nasal symptoms. There was also significant decrease in salivar production and nasal mucosa changes in patients of Group 1

A number of experimental and theoretical studies, performed in the field of technical flow duct acoustics are presented in this thesis. The acoustical methods treated are implemented on turbocharged IC-engines and engine gas exchange system components. A new method based on the well-known two-load technique has been developed. The method was applied to characterise the source data of various piston-engines with non-linear behaviour including a 6 cylinder turbo-charged truck diesel engine. The source characterisation results were compared to the results obtained using the linear two-load technique. It was demonstrated that the new non-linear multi-load technique gives improved results when the source is slightly non-linear. The use of active one-port models has been tested to characterize an air terminal device (ATD) as a source of flow generated noise. In order to predict the noise generation at different operating points of the device a scaling law was derived and verified. In the experimentally derived scaling law a flow speed dependence of 3 was found for the narrow band spectra, corresponding to a dipole-like behavior of the source in the plane wave range. The proposed technique was validated successfully and the results indicated a good prediction of in-duct sound generation by the air terminal device. Sound reflection from hot flow duct openings has been investigated experimentally. The reflection coefficient was measured for flow temperatures up to 500 ºC and jet velocities up to 108m/s. The results have been compared with famous Munt’s theory. It was concluded that at low Mach number and Helmholz number cases the results agree well with the Munt’s model. This was the first experimental validation of the theory for hot flow conditions. Experimental procedures to determine the sound transmission through automotive turbo-charger compressors were developed and described in detail. An overview of a unique turbocharger testing facility established at KTH CICERO in Stockholm is given. The facility can be used to measure acoustic two-port data for turbo-compressors. Results from measurements on a passenger car turbo-compressor are presented and the influence of operating conditions on the sound transmission is discussed. Current wave action models developed in CMT for computation of the gas exchange processes in I.C. engines have been implemented to determine the acoustic wave transmission through the turbo- compressor. The models are validated with the experimental data and the results are presented for different operating conditions of a Volvo passenger car turbo-compressor. / QC 20100809

Introdução: A radioiodoterapia (RIT) constitui tratamento consagrado para carcinomas diferenciados de tireoide, sendo amplamente utilizada em todo o mundo, tendo-se em vista a incidência crescente desse tipo de neoplasia maligna. Embora efeitos adversos graves sejam infrequentes, são descritas complicações como xerostomia, sialoadenite e disfagia. O acometimento de olhos e anexos é pouco discutido, sendo relatadas xeroftalmia, ceratoconjuntivite e obstrução de vias lacrimais (OVL), notadamente após altas doses cumulativas do radiofármaco. A incidência de OVL e a eventual relação com outros sintomas oculares ou extraoculares não são bem estabelecidas. Neste estudo, buscamos determinar a frequência de obstrução de vias lacrimais (OVL) em pacientes submetidos à RIT, a existência de fatores preditores de OVL e a relação entre alterações de superfície ocular, xerostomia e alterações da mucosa nasal. Métodos: Foram avaliados pacientes com diagnóstico de carcinoma diferenciado de tireoide submetidos à RIT (Grupo 1) e não submetidos à RIT (Grupo 2) no período pré-operatório, pós-operatório e no 2º, 4º, 6º e 12º mês pós-cirurgia ou pós-RIT. Os pacientes foram submetidos a avaliações da superfície ocular e do filme lacrimal, sondagem e irrigação de vias lacrimais, quantificação da produção salivar e endoscopia nasal. As avaliações subjetivas de sintomas oculares, nasais e de xerostomia foram realizadas, respectivamente, por meio dos questionários OSDI, NOSE e Xerostomia Inventory. Resultados: O Grupo 1 (n=44, 88 olhos) apresentou 3 pacientes (04 olhos) com OVL, o que corresponde à incidência de 4,55% (4 eventos em 88 olhos) ou 6,8% (3 casos em 44 pacientes). O Grupo 2 (n=43, 86 olhos) não apresentou nenhum caso de OVL, fato que impossibilitou o cálculo da razão de chances (odds ratio). A avaliação objetiva da superfície ocular não apresentou diferenças significantes entre os grupos. Por outro lado, a avaliação endoscópica nasal revelou maior palidez de mucosa no Grupo 1 no 2º mês (OR: 3,61; IC 95%: 1,44-9,09; p < 0,01), 4º mês (OR: 4,00; IC 95%: 1,48-10,79; p < 0,01) e 12º mês de seguimento pós-RIT (OR: 3,24; IC 95%: 1,14-9,22; p=0,03), com piora do escore de aparência endoscópica quanto a edema, a pólipos e à secreção no 6º mês de seguimento pós-RIT, em comparação à avaliação pré-operatória (p < 0,01). Os resultados do questionário OSDI demonstraram piora do escore no Grupo 1 no 2º mês (p < 0,01), 4º mês (p < 0,01), 6º mês (p < 0,01) e 12º mês (p < 0,01) de seguimento pós-RIT em comparação à avaliação inicial pré-operatória. A avaliação pelo questionário NOSE demonstrou piora dos sintomas nasais no Grupo 1 no 2º mês (p=0,02) e no 4º mês de seguimento pós-RIT (p < 0,01), em comparação aos sintomas pré-operatórios. A avaliação da xerostomia demonstrou piora dos sintomas no Grupo 1 em relação à avaliação pré-operatória e no 2º mês (p < 0,01), 4º mês (p < 0,01), 6º mês (p < 0,01) e 12º mês (p=0,01) de seguimento pós-RIT, bem como diminuição objetiva da produção salivar até o 12º mês pós-RIT (p < 0,01). Conclusões: Embora em pequeno número, o presente estudo demonstrou aparecimento de casos de obstrução lacrimal, mesmo que assintomáticas, nos primeiros 12 meses após-RIT. Não foi possível estabelecer relação da OVL com eventuais fatores preditores. Entretanto, demonstrou-se piora subjetiva da xerostomia, da xeroftalmia, dos sintomas nasais e significativa alteração da mucosa nasal nos pacientes do Grupo 1 / Introduction: Radioiodine therapy (RIT) is an established treatment for differentiated thyroid carcinomas and is widely used throughout the world, given the increasing incidence of this malignancy. Although serious adverse effects are infrequent, complications such as dry mouth, sialadenitis and dysphagia have been described. The involvement of the eyes and adnexa is not commonly discussed, despite dry eye, keratoconjunctivitis and lacrimal system obstruction (LSO) being reported, especially after high cumulative doses of this radiopharmaceutical. The incidence of LSO and any relationship with other ocular or extraocular symptoms are not well established. The study objectives were to determine the frequency of lacrimal system obstruction (LSO) in patients undergoing RIT, the existence of predictive factors of LSO and the relationship between ocular surface changes, xerostomia and changes in nasal mucosa. Patients and Methods: Patients with differentiated thyroid carcinoma undergoing (Group 1) and not undergoing (Group 2) RIT were evaluated in the preoperative and postoperative periods and 2, 4, 6 and 12 months post-surgery or post-RIT. Patients underwent ocular surface and tear film evaluation, lacrimal system probing and irrigation, quantification of salivary production and nasal endoscopy. The subjective evaluations of ocular symptoms, nasal symptons and xerostomia were done, respectively, through the OSDI, NOSE and Xerostomia Inventory questionnaires. Results: Group 1 (n = 44, 88 Eyes) had 3 patients (4 eyes) with LSO, corresponding to an incidence of 4.55% (4 events in 88 eyes) or 6.8% (3 cases in 44 patients). Group 2 (n = 43.86 eyes) did not present any cases of LSO, that makes it impossible to calculate the odds ratio. Objective assessment of ocular surface did not show significant differences between groups. On the other hand, nasal endoscopy revealed larger mucosa pallor in Group 1 in the 2nd month (OR: 3.61; 95% CI: 1.44 to 9.09; p < 0.01), 4th month (OR: 4.00; 95% CI: 1.48 to 10.79; p < 0.01) and 12th month after RIT (OR: 3.24; 95% CI: 1.14 to 9.22; p = 0.03), with worsening of the endoscopic appearance score in the 6th month after RIT, compared to the preoperative evaluation (p < 0.01). The results of the questionnaires showed worsening OSDI score in Group 1 at 2nd month (p < 0.01), 4th month (p < 0.01) and 6 months (p <0.01) and 12 months (p < 0, 01) post RIT as compared to the preoperative baseline. The evaluation by the NOSE questionnaire showed worsening of nasal symptoms in Group 1 in the 2nd month (p=0.02) and 4th month (p < 0.01) after RIT, compared to preoperative data. The evaluation of xerostomia showed worsening of symptoms in Group 1 compared to preoperative assessment at 2nd month (p < 0.01), 4th month (p < 0.01), 6th month (p < 0.01) and 12 months (p = 0.01) after RIT. Objective decreased saliva production was observed until the 12th month after RIT (p < 0.01). Conclusions: Although in small number, the present study demonstrated the emergence of cases of lacrimal obstruction, even if asymptomatic, in the first 12 months after RIT. It was not possible to establish a relationship between LSO and predictive factors. However, it was demonstrated subjective worsening of xerostomia, xerophthalmia and nasal symptoms. There was also significant decrease in salivar production and nasal mucosa changes in patients of Group 1

The aim of the work reported in this thesis is to establish a generic approach for the study of the propagation of higher-order modes in ducts of circular cross section when a simple aperture device is installed in the duct. Additionally to describe the effects of the simple aperture device on the whole in duct acoustic field, especially in the frequency range after the first higher-order mode cuts on. The approach, which is based on approximating each higher-order mode as an uncoupled mode, requires an accurate and effective decomposition of the in duct field in the higher frequency range. In the theoretical work for the propagation of the higher-order modes in circular ducts, one established model to describe the open end of the duct is considered. Another model to describe the sound source (both plane wave source and point source) and the boundaries between the aperture device and the main duct is proposed. Combining the two models together, a revised model to describe the whole acoustic system is obtained and used to carry out the in duct field decomposition in the higher frequency range. From this the amplitudes of various higher-order modes are obtained. Experimental investigations have also been carried out to determine the applicability of this model. The experimental work can be divided into two groups: reference measurements for the inputs to the models and direct measurements of the sound fields. The reference measurements are used to obtain the strength of the sound source. The direct measurements are used to compare with the results obtained from the theoretical calculations. Through the comparison, the errors and the applicability of the theoretical model are established. It is shown that this approach to the problem may be used in the normalized wave number region up to k * R -< 7 , which is nearly four times the plane wave region and includes sixteen propagating higher-order modes. By determining the amplitudes of the higher-order modes, the whole in-duct acoustic field is fully decomposed into individual model contributions and can be reconstructed in detail. In order to get a complete and coordinate-independent description of the effects of installing different simple aperture devices, the power radiated out of the open end of - i - the duct is calculated in the fonn of different single modes. Additionally the insertion losses for different aperture device situations are also obtained. Then through the comparison of the powers and the insertion losses, it is possible to find an effective and direct way to express the effects of installing different simple aperture devices in a duct.

Dans cette thèse, des méthodes de caractérisation acoustique passive et active de systèmes acoustiques à deux ports sont présentées, basées sur une décomposition d’ondes planes en entrée et sortie. Cette décomposition est réalisée par la méthode du beamforming. Ces méthodes mises en place et validées sur des géométries simples, sont ensuite employées pour caractériser l’étage compresseur d’un turbocompresseur de suralimentation automobile. La caractérisation acoustique active se fait par la mesure de la puissance et de l’intensité acoustique dans les conduits du compresseur, ceci pour des points de fonctionnement spécifiques, des cartographies compresseur complètes sont également élaborées. Les essais ont été menés sur banc turbo, banc moteur et sur véhicule complet. La caractérisation acoustique passive est abordée par le calcul de matrices du compresseur (matrice de transfert, matrice d’impédance et matrice de diffusion). Le calcul de la perte par transmission acoustique est déduit de ces matrices. Des essais ont été réalisés et comparés à des simulations éléments finis 3D sur un turbocompresseur statique comme sur un turbocompresseur opérationnel. / In this thesis, methodologies to perform the acoustic passive and active characterization of two port systems are presented. These methods are based on plane wave decomposition made at the inlet and at the outlet of the system. This decomposition is made according beamforming technique. Once these methods were validated on simple geometries, they were then applied to the compressor stage of an automotive turbocharger. The active acoustic characterization is made by the measurement of the acoustic power and acoustic intensity in the compressor ducts on given working points, but also on complete compressor maps. This was performed on turbocharger benches, engine benches and a complete vehicle. The passive acoustic characterization is made by the calculation of characteristic matrices (transfer matrix, impedance matrix and scattering matrix). These matrices are then used to compute the acoustic transmission loss. Experiments were performed on a static turbocharger and compared to 3D finite elements simulations, as well as experiments on an operating turbocharger.

Introdução: O sucesso da cateterização da via biliar é de importância para o diagnóstico e terapêutica nas afecções biliopancreáticas nos procedimentos de colangiopancreatografia retrógrada endoscópica (CPRE) e está associado a complicações graves e mortalidade. O objetivo do estudo foi comparar o sucesso, perfil laboratorial e as complicações da técnica de fistulotomia papilar direta com o acesso cateter e fio-guia. Métodos: No período de julho de 2010 a maio de 2017 foram selecionados e randomizados para CPRE em dois grupos: cateterização com cateter e fioguia (Grupo I) e a fistulotomia papilar (Grupo II). As curvas de amilase, lipase e proteína C reativa (T0, 12 e 24 horas) e as complicações (pancreatite, sangramento e perfuração) foram avaliadas após CPRE. Resultados: Foram incluídos 102 pacientes (66 do sexo feminino e 36 do masculino, com idade média de 59,11±18,7 anos) e divididos em 51 pacientes para Grupo I e 51 no Grupo II. Os sucessos das cateterizações dos Grupos I e II foram de 76,47% e 100%, respectivamente (p=0,0002). Doze pacientes (23,53%) do Grupo I foram considerados pacientes de cateterização difícil e submetidos à fistulotomia papilar com sucesso no acesso biliar. Foram observadas 13,7% (2 perfurações e 5 pancreatites leves) e 2 % (1 paciente com perfuração e pancreatite) complicações nos Grupos I e II, respectivamente (p=0,062). Conclusão: A fistulotomia papilar demonstrou maior eficácia na cateterização da via biliar e com menor índice de amilasemia e lipasemia em comparação a cateterização com papilótomo e fio guia. As complicações foram semelhantes entre as duas técnicas / Background: The success of biliary tract cannulation is important for the diagnosis and treatment of biliopancreatic diseases in endoscopic retrograde cholangiopancreatography (ERCP) procedures. ERCP is associated with severe complications and mortality. The aim of the study was to compare the success, laboratory profile and complications of the direct papillary fistulotomy technique with standard catheter and guidewire access. Methods: In the period from July 2010 to May 2017, two groups were selected and randomized for ERCP: cannulation with catheter and guidewire (Group I) and papillary fistulotomy (Group II). The curves of amylase, lipase and C-reactive protein (T0, 12 and 24 hours) and complications (pancreatitis, bleeding and perforation) were evaluated after ERCP. Results: A total of 102 patients (66 females and 36 males, mean age 59.11 ± 18.7 years) were divided into 51 patients for Group I and 51 for Group II. The success of cannulation was 76.47% and 100%, in Groups I and II, respectively (p = 0.0002). Twelve patients (23.53%) of Group I were considered to have difficult cannulation and were submitted to fistulotomy with successful biliary access. There were 13.73% (2 perforations and 5 mild pancreatitis) and 2% (1 patient with perforation and pancreatitis) complications in Groups I and II, respectively (p=0,062). Conclusion: Papillary fistulotomy demonstrated greater efficacy in the bile duct cannulation and presented lower serum amylase and lipase compared with standard catheter and guidewire cannulation. Complications were similar in the two techniques