O objetivo desta Dissertação foi analisar o efeito do tratamento térmico de alívio de tensões pós-soldagem sobre a microestrutura e comportamento mecânico de soldas produzidas com arame tubular rutílico AWS E-81T1 Ni1. Foi soldada uma junta com 60 mm de espessura, na posição vertical e progressão ascendente. Esta junta foi dividida em três partes, sendo uma mantida como soldada e as outras duas tratadas termicamente por 6 horas em diferentes temperaturas, 585 °C e 650 °C. Avaliou-se o efeito do tratamento térmico sobre as propriedades mecânicas por meio de ensaio de dureza, tração e impacto Charpy-V. A caracterização microestrutural foi realizada por microscopia óptica e microscopia eletrônica de varredura. As observações experimentais mostraram uma diminuição da tenacidade ao impacto no material tratado termicamente, com uma tendência para uma queda maior com o aumento da temperatura do tratamento térmico. Este comportamento pode ser atribuído principalmente à precipitação e crescimento de carbonetos. Não foi observada a presença de mecanismos de fratura intergranular. Provavelmente o metal de solda estudado não possuía nível de impurezas suficiente para a ativação deste mecanismo. / The objective of this Dissertation was to analyze the effect of postweld heat treatment on microstructure and mechanical behavior of welds obtained by flux cored wire AWS E-81T1 Ni1. It was welded a joint with 60 mm thickness, on vertical position and ascendant progress. This joint was divided in three parts, one maintained as welded and two others heat treated for 6 hours on different temperatures, 585 °C and 650 °C. The effect of the heat treatment on mechanical properties was evaluated by means of hardness, tensile and impact Charpy-V tests. The characterization of the microstructure was undertaken utilizing optical and scanning electron microscopy. The experimental results revealed a decrease of impact toughness in heat treated material, with a tendency to a low impact toughness for high heat treatment temperature. This behavior may principally be attributed to an increase precipitation and growth of carbides. No intergranular fracture mechanism was observed. Probably the level of impurities in the weld metal studied was not high enough to provoke such phenomena.

Este trabalho apresenta a aplicação da teoria de Controle Robusto H-infinito em modelo não linear de sistema de suspensão ativa com Atuador Tubular de Ímã Permanente (ATIP). Os principais objetivos na aplicação dos sistemas ativos de suspensão são a obtenção de melhores níveis de conforto do usuário e dirigibilidade do veículo em relação aos sistemas de suspensão passivo e semi-ativo, e a manutenção dos limites de deslocamento da suspensão. Inicialmente, são apresentados os modelos de suspensão ativa de um quarto de carro e carro completo, utilizados respectivamente como planta para o projeto dos controladores H-infinito e como modelo para as simulações dos sistemas de suspensão em malha fechada. Em seguida, o conjunto de controladores H-infinito e desenvolvido, baseado em especificações de projeto definidas, para posterior avaliação e comparação dos sistemas projetados. Verificações de robustez dos sistemas de suspensão ativos, utilizando-se da Análise-µ como ferramenta de avaliação, são feitas em conjunto com as análises de desempenho de cada sistema. A avaliação de desempenho dos sistemas é realizada tanto no domínio do tempo (avaliando-se angulações, velocidades, acelerações, defexões e energia do sistema) quanto no domínio da frequência (através da análise de densidade espectral de potência, ou Power Spectral Density (PSD), das acelerações verticais do veículo e do esforço de controle do atuador). A excitação do sistema é realizada por meio de distúrbios impostos às posições das rodas, dos tipos determinístico e estocástico, representativos de condições reais da aplicação de um veículo. O conjunto de controladores desenvolvido neste trabalho apresenta resultados satisfatórios para distúrbios de entrada do tipo determinísticos e estocásticos, com ganhos de desempenho dos sistemas de suspensão ativa em relação ao sistema passivo de referência de até 34; 92% para a métrica de avaliação do conforto do usuário, de 17; 23% para a métrica da manutenção da dirigibilidade, e de 43; 48% e 30; 10% para as métricas das acelerações dos ângulos de arfagem e de rolagem da carroceria, respectivamente. / This work presents the application of the H-infinity robust control theory into a non-linear model of active suspension system with a Tubular Permanent Magnet Actuator (TPMA). The main objectives in the application of the active suspension systems are the achievement of greater levels of comfort to the user and of road holding for the vehicle, when compared to the passive and semi-active suspension systems, besides the maintenance of suspension displacement limits. Initially are presented the active suspension models of a quarter-car and of a full-car, used respectively as a plant for the design of the H-infinity controllers and as a model for the simulations of the closed loop suspension systems. In the sequel, the controllers are developed, based on properly defined specifications, for further evaluation and comparison among the systems designed. Robustness verications of the active suspension systems, using the µ-Analysis as assessment tool, are performed together with the performance analysis of each system. The performance evaluation of the systems is performed both in the time domain (assessing angles, speeds, accelerations, dections and the energy of the system) and in the frequency domain (through the analysis of Power Spectral Density (PSD) of vertical accelerations of the vehicle and the control efort of the actuator). The excitation of the system is carried out by means of disturbances imposed to the vertical wheel\'s positions. Those disturbances are of deterministic and stochastic types, which are representatives of real working conditions of the vehicle. The set of controllers developed in this work presents satisfactory results for both deterministic and stochastic input disturbances, with performance gains of the active suspension systems in relation to the passive system of reference up to 34; 92%, 17; 23%, 43; 48% and 30; 10% respectively to the assessment metrics of user comfort, handling maintenance and acceleration of the pitch and roll angles of the chassis.

In this thesis work, a new distributed amplifier topology is discussed and applied to three different cases. The topology is based on dividing the frequency spectrum into channels and amplifying afterwards. The channelized and amplified signals are then combined at the output for broadband amplification. This topology is used in the design of a three channel 0.1-1 GHz amplifier with a gain of 14.5&plusmn / 0.6 dB. The design is fabricated, and then the measured and simulated results are compared. A second 0.1-1 GHz amplifier with 21&plusmn / 1 dB is designed in simulation environment with five channels. This five channel amplifier is fabricated and measured results are compared with the simulated ones. A 1-6 GHz three channel amplifier is also designed with a gain of 10.5&plusmn / 0.5 dB. Application of the proposed topology to three different designs shows promising results for future amplifier designs.

Water resources are increasingly precious, so wastewater reclaiming has become an important source of water nowadays. There are many types of industry including conventional and hi-tech ones in the selected industrial processing zone, where different process wastewaters are treated by a centralized wastewater treatment plant. The effluent is then discharged into the ocean (EDO). On the other hand, among several other industries backside grinding (BG) wastewater generated by the IC (integrated-circuit) packaging and testing industry is treated by their owned wastewater treatment plants and then discharged onto land (EDL). Normally, BG wastewater is huge in quantity and it contains microscale and nanoscale particles. The objectives of this research were two-fold: (1) to evaluate the feasibility of using two tubular ceramic membranes (microfiltration and ultrafiltration) coupled with the electrocoagulation/electrofiltration (EC/EF) process to effectively treat the effluent discharged into the ocean, effluent discharged onto land, and BG wastewater for the purpose of reclamation; and (2) to investigate the best time for backwashing of membranes through the analysis of components of membrane fouling using resistances in series model. The experimental results showed that the ultrafiltration (UF) membrane (i.e., tubular TiO2/Al2O3 composite membrane) outperformed the mictrofiltration (MF) membrane (i.e., tubular Al2O3 membrane) in terms of permeate quality. But, generally, the later yielded a greater membrane flux. In the case of BG wastewater by UF and EC/EF, the quality of permeate met the tap water standards in terms of water quality items analyzed. As for EDO and EDL further treated by UF and EC/EF, all the analyzed water quality items of permeate, except pH and total dissolved solids, met the tap water standards in Taiwan. Thus, more efforts have to be made to reclaim these two types of effluent. Finally, the components of membrane fouling were analyzed using resistances in series model for the tested water specimens. The results showed that generally the irreversible resistance component (Rirr) had a greater contribution to a better quality of permeate than that of the reversible resistance component (Rr). It was also found that the magnitude of Rirr of BG wastewater was greater than Rirr values of the other two effluents. This might explain why the quality of permeate of the former was better than the latter. The results further indicated that Rr increased more than Rirr as the operating time elapsed, resulting in a limited improvement of permeate quality even a longer treatment time was employed. To recover the membrane flux to its optimum, in this study the best time for backwashing of membrane was determined based on the time at which Rr was greater than Rirr. However, the flux recovery was found to be in the range of 60-77% as compared with the initial flux for a virgin membrane in treating new batch of water specimens. The fraction unable to recover by backwashing might be contributed by Rirr in the membrane pores. A further acid washing would resolve this problem.

The seismic response of steel monopole wind turbine towers is investigated and their risk is assessed in the Canadian seismic environment. This topic is of concern as wind turbines are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. An implicit finite element model of a 1.65MW tower was developed and validated. Incremental dynamic analysis was carried out to evaluate its behaviour under seismic excitation, to define several damage states, and to develop a framework for determining its probability of damage. This framework was implemented in two Canadian locations, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, as is the design spectrum. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under seismic loading for future considerations.

The seismic response of steel monopole wind turbine towers is investigated and their risk is assessed in the Canadian seismic environment. This topic is of concern as wind turbines are increasingly being installed in seismic areas and design codes do not clearly address this aspect of design. An implicit finite element model of a 1.65MW tower was developed and validated. Incremental dynamic analysis was carried out to evaluate its behaviour under seismic excitation, to define several damage states, and to develop a framework for determining its probability of damage. This framework was implemented in two Canadian locations, where the risk was found to be low for the seismic hazard level prescribed for buildings. However, the design of wind turbine towers is subject to change, as is the design spectrum. Thus, a methodology is outlined to thoroughly investigate the probability of reaching predetermined damage states under seismic loading for future considerations.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Pouco se sabe a respeito das consequências da operação de reparo nas propriedades mecânicas e metalúrgicas das juntas do aço ASTM A335 grau P91 soldadas por Arame Tubular. Neste trabalho foi realizado um estudo para analisar e caracterizar juntas de um tubo do aço P91 soldadas pelo processo Arame Tubular com proteção gasosa, antes e após situação de duplo reparo. Foram utilizadas técnicas de microscopia eletrônica de varredura (MEV), análise química semiquantitativa por EDS (Energy Dispersive Spectroscopy), microscopia óptica (MO), além da obtenção de medidas de microdureza Vickers e realização de ensaios de impacto e tração à temperatura ambiente. A macrografia revelou a existência de uma nova zona termicamente afetada formada no centro da junta reparada e a análise micrográfica mostrou que esta zona apresentou uma pequena tendência a formação de grãos menores do que na zona de fusão que sofreu reparo, além disso, a região tinha grãos colunares que não são característicos de uma zona termicamente afetada e quantidade de carbonetos menor comparativamente. Não houve variações significativas nos valores de tração e microdureza. Os ensaios de impacto revelaram baixos valores de energia absorvida na zona de fusão do 2 reparo, no entanto, todas as outras zonas avaliadas das juntas com e sem reparo apresentaram valores dentro das especificações. / Little is known about the consequences of the repair operation on the mechanical and metallurgical properties of ASTM A335 grade P91 steel joints welded by Flux-Cored Arc Welding (FCAW). In this work, a study was made to analyze and characterize joints of P91 steel tube, welded by FCAW with shielding gas, before and after double repair situation. Techniques of scanning electron microscopy (SEM), chemical analysis by semi-quantitative EDS (Energy Dispersive Spectroscopy) and optical microscopy (OM) were used, in addition, Vickers microhardness measurements, impact and tensile tests at room temperature, were carried out. The macrography revealed the existence of a new heat affected zone formed in the center of the repaired joint and the micrographic analysis showed that this zone has a tendency to formation of smaller grains compared to the repaired fusion zone, furthermore, the region has columnar grains which are not characteristics of a heat affected zone and comparatively lesser amounts of carbides. There were no significant variations in the tensile and hardness values. Impact tests showed low values of absorbed energy in the fusion zone of the second repair; however, all other evaluated zones, with and without repair, had values within specifications.

Este trabalho foi desenvolvido no programa de Mestrado Interinstitucional - MINTER - entre a UTFPR e o IFAM, com financiamento da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES - através do projeto ACAM 1379/2006 e da Superintendência da Zona Franca de Manaus - SUFRAMA - através do convênio 084/2005. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES- através do projeto ACAM 1379/2006 e da Superintendência da Zona Franca de Manaus - SUFRAMA - através do convênio 084/2005. / Esta pesquisa tem por finalidade analisar a influência de parâmetros do processo de soldagem com arame tubular com proteção gasosa (Gás Shielded Flux Cored Arc Welding - FCAW-G) nas características da solda do aço ASTM A-36. Parâmetros como tensão do arco (V), velocidade de alimentação do arame (Valim) e distância bico de contato-peça (DBCP) foram variados a fim de detectar suas influências sobre a largura, a penetração, o reforço do cordão e a dureza do metal de solda. Além disso, foi determinada a influência desses parâmetros na taxa de deposição do material de adição, sendo ensaiadas, as soldas, quanto às resistências à tração e ao impacto (ensaio Charpy criogênico) para determinar a qualidade recomendada por norma. As medições geométricas dos cordões de solda foram realizadas em macrografias obtidas da seção transversal da solda, por meio de microscópio óptico, bem como as análises da microestrutura. As medições de dureza foram realizadas com durômetro na seção transversal dos cordões. A taxa de deposição, em kg/h, foi determinada pela pesagem dos corpos-de-prova antes e depois da deposição da solda. Verificou-se que, de forma geral, a morfologia do cordão (largura, penetração e reforço) foi grandemente influenciada pela velocidade de alimentação do arame, seguida pela tensão de soldagem e pela distância bico de contato-peça. Da mesma maneira, a taxa de deposição foi influenciada diretamente pela velocidade de alimentação, pela tensão e pela DBCP: a primeira, com um acréscimo significativo (24,08%); a tensão de forma não muito intensa (4,17%). Desta maneira é possível afirmar, com base nos valores dos parâmetros utilizados neste trabalho, que a maior taxa de deposição (4,32 Kg/h), a melhor morfologia do cordão de solda e dureza adequada foram obtidas com Valim de 12,5 m/min, tensão de 34 V e DBCP de 16 mm. / This research aims to analyze the influence of the parameters of Gas Shielded Flux Cored Arc Welding (FCAW-G) on the characteristics of welding steel ASTM A-36. Parameters such as arc voltage (V), feed speed of the wire (Valim) and stickout (distance nozzle contact piece - DBCP) were varied to detect their influence on the width, penetration, reinforcement of the cord, and the hardness of metal weld. Furthermore, it was determined the influence of these parameters on deposition rate of filler metal and the welds were tested for resistance to tensile and impact strength (Charpy test) to determine the quality of the recommended standard. The geometric measurements of weld were carried out in macrographs by the obtained from the cross section of the weld, through an optical microscope as well as the analysis of the microstructure. The hardness measurements were carried out with durometer in cross section of the fillets. The deposition rate in kg/h was determined by weighing the specimen before and after the deposition of solder. It was found that in general the morphology of the cord (width, penetration and reinforcement) was greatly influenced directly by the feed speed of the wire, followed by welding voltage, and stickout. Similarly, the deposition rate was directly influenced by the feed speed, voltage and DBCP, the first with a significant increase (24, 08%), and the tension witch a not so intensive effect (4, 17%). Thus it can be said based on the values of the parameters used in this study that the highest rate of deposition (4,32 kg/h), the better morphology of the weld cord and appropriate hardness was obtained with Valim of 12.5 m/min, voltage 34 V and 16 mm DBCP .

Cette thèse s’intéresse à la fabrication de pièces composites par le procédé Resin Transfert Molding (ou RTM), appliquée à des tubes de protection thermiques. Plus particulièrement, cette thèse vise à démontrer la faisabilité d’utiliser ce procédé pour la fabrication cette pièce complexe. La phase d’imprégnation de préformes sèches est plus particulièrement étudiée. Après mise en oeuvre, cette pièce peut présenter des défauts tels que de la porosité ou des déplacements de plis constituant la préforme. L’objectif de cette thèse est donc de comprendre l’origine de ces défauts et de minimiser voire de d’empêcher leur apparition. Pour cela, une démarche expérimentale a été mise en place. Celle ci comprend la réalisation d’un pilote de laboratoire permettant d’appliquer différentes conditions d’imprégnation aux préformes considérées. La perméabilité des renforts considérés a aussi été évaluée à différentes échelles grâce à l’utilisation de moyen dédiés à l’échelle macroscopique (banc de perméabilité planaire et transverse), et grâce à l’utilisation d’un code de calcul se basant sur des images de tomographie synchrotron à l’échelle microscopique. Enfin, une analyse de la qualité des prototypes réalisés a été menée en suivant des procédures mises en place lors de ce projet et les résultats analysés et mis en relation avec les conditions de mise en oeuvre. Cette approche expérimentale est couplée aux simulations numériques de la phase d’imprégnation que nous avons aussi mise en oeuvre au cours de cette thèse. Par l’utilisation combinée de la simulation numérique et des essais expérimentaux, nous avons défini des critères estimant le risque d’apparition des défauts. Ces critères ont montré leur efficacité sur les solutions innovantes que nous avons proposées puisque répondant aux exigences du cahier des charges industriel. / This work concerns the manufacturing of composite parts using the Resin Transfer Molding (RTM) process. A major goal of this study is to test the feasibility of using this process to manufacture a thick tubular part with a complex shape. This study concerns the different stages of the process with an important focus on the injection step of dry preforms. The goal of this thesis is to understand the generation of manufacturing defect (mainly porosity and preform deformation) that possibly takes place during the injection step to avoid them. An experimental procedure is proposed. An experimental setup was developed to study the influence of the different process parameters on the quality of the composite parts. The determination of the longitudinal and through the thickness permeabilities was conducted experimentally on sheared and un-sheared samples. An alternative technique to estimate the permeability is presented based on simulation software using X-ray tomography images at the microscale. At last, a quality control procedure was developed and applied to the tubes manufactured within this project. This experimental work was compared to numerical simulations of the injection stage. Using both numerical simulations and experiments, criteria on process and material parameters to predict the quality of the tailored parts are presented. Those criteria are successfully compared to experimental data and were applied to design innovative injection solutions that meet industrial specifications.

Introdução: Em torno de 30 a 50% dos pacientes críticos desenvolvem insuficiência renal aguda (IRA), sendo que sua progressão leva à necessidade de terapia renal substitutiva (TRS). Dentre os sobreviventes, em torno de 15 a 23% possuem a necessidade de diálise após alta. A ocorrência da insuficiência renal aguda tem sido associada à futura progressão para doença renal crônica. É possível que marcadores tubulares estejam alterados após a recuperação da IRA, antecipando o desenvolvimento de doença renal crônica. Objetivos: Comparar a β2 Microglobulina, as enzimas urinárias N-acetil- β-D-glucosaminidase, lactato desidrogenase e fosfatase alcalina, as frações de excreção de magnésio, fósforo, potássio e ácido úrico e o gradiente transtubular de potássio, bem como a presença de microalbuminúria e proteinúria entre pacientes normais sem qualquer história prévia de dano ou qualquer tipo de disfunção renal, com pacientes sobreviventes de IRA severa com necessidade de hemodiálise que recuperaram função renal de forma a avaliar se existem diferenças entre os 2 grupos. Métodos: Foram incluídos pacientes que apresentaram insuficiência renal aguda com necessidade de hemodiálise internados no centro de terapia intensiva (CTI) do Hospital de Clínicas de Porto Alegre e que receberam alta nos períodos de 2007 a 2010, sem apresentar as seguintes co-morbidades: insuficiência renal crônica, hepatopatia crônica, pacientes HIV positivo, transplantados, doença vascular severa, diabetes com complicações crônicas e rim único funcionante e que apresentavam função renal normal definida por taxa de filtração glomerular > 60 mL/min/1.73m2 calculada pela equação CKD-EPI. Os mesmos foram comparados com voluntários sadios pareados por sexo e idade (+/- 4 anos). Para avaliação das frações de excreção e do gradiente transtubular de potássio foram feitas análises excluindo o uso de medicamentos diuréticos, inibidores da ECA e bloqueadores dos receptores de angiotensina. Resultados: A fração de excreção de magnésio encontrou-se aumentada no grupo com IRA prévia seguida por um menor gradiente transtubular de potássio bem como lactato desidrogenase elevada. O grupo com IRA prévia apresentou proteinúria e microalbuminúria e embora sem significância estatística (P=0,052) uma maior fração de excreção de fósforo. Conclusão: Mesmo com taxa de filtração glomerular normal comparável, os sujeitos do grupo com ira prévia apresentaram sugestivas alterações em nível tubular refletidas por maior fração de excreção de magnésio, elevada lactato desidrogenase e um menor gradiente transtubular de potássio, microalbuminúria e proteinúria que refletem um possível dano renal. Estes achados levam à hipótese de que sujeitos com prévia IRA severa com necessidade de terapia de renal substitutiva, apresentam uma possível sequela relativa à IRA prévia ou uma predisposição para insuficiência renal crônica. / Background: About 30 to 50% of the critically ill patients develop acute renal failure (ARF) and the progression leads to the need of renal replacement therapy. Between the survivors 15 to 23% has the need of dialysis after discharge. The severity of the ARF is a robust predictor for the development of a future chronic kidney disease. The occurrence of acute renal failure has been associated with future progression of chronic kidney disease. Objective: Compare β2-microglobulin, the urinary enzymes N-acetyl-β- D-glucosaminidase, lactate dehydrogenase, alkaline phosphatase fractional excretion of magnesium, phosphorous, potassium and uric acid transtubular potassium gradient, including the presence of microalbuminuria and proteinuria between subjects with normal renal function without any previous history of acute renal injury or any kind of renal dysfunction with survivors of severe ARF with the needed of hemodialysis that recovered renal function in order to evaluate if there are differences between the 2 groups. Methods: It was enrolled patients that presented acute renal failure with the need of hemodialysis hospitalized on intensive care unit (ICU) and discharged on the period of 2007 to 2010 at Hospital de Clínicas de Porto Alegre, without the following co-morbidities chronic renal failure, chronic hepatopathy, positive HIV, transplants, severe vascular disease, diabetes with chronic complications and single functioning kidney that presented normal renal function defined as glomerular filtration rate (GFR) > 60 mL/min/1.73m2 calculated by CKD EPI formula The subjects were compared with healthy volunteers and paired by sex and age (+/- 4 years). To evaluate fractional excretions and transtubular potassium gradient, analyses were made excluding subjects that were taken diuretic medication, ACE inhibitors and angiotensin block receptors. Results: The fractional excretion of magnesium was finding increased on the previous ARF group followed by a lower transtubular potassium gradient and elevated lactate dehydrogenase. The previous ARF group showed proteinuria and microalbuminuria and although without statistical significance (p=0.052) an elevated phosphorous excretion. Conclusion: Although normal glomerular filtration rate, the subjects with previous ARF, showed suggested tubular alterations reflected by a higher fractional excretion of magnesium, elevated lactate dehydrogenase and a lower transtubular potassium gradient, microalbuminuria and proteinuria that reflects a possible renal damage. Those findings lead to the hypothesis that subjects with previous severe ARF with the need of renal replacement therapy present a possible sequel related to previous ARF or a predisposition to chronic kidney disease.