Dentro da classe Reptilia, a ordem Testudines possui algumas características exclusivas, tais como a fusão das costelas e da coluna vertebral e a perda dos músculos intercostais, inviabilizando a ventilação costal. Além disso, as posições naturais que os Testudines exibem podem influenciar a mecânica ventilatória. O presente estudo teve como objetivo testar a influência do posicionamento do corpo sobre a mecânica ventilatória através da complacência estática e dinâmica e analisar através da respirometria aberta o padrão ventilatório e o custo metabólico da ventilação através da exposição em normóxia, hipóxia e hipercarbia em Trachemys scripta e Chelonoidis carbonarius. Os volumes pulmonares, complacência estática e dinâmica em C. carbonarius foram inferiores aos de T. scripta e outras espécies de Testudines já estudadas. Verificou-se também influência das posições sobre a mecânica ventilatória nas duas espécies, sendo a posição de membros e cabeça retraídos na carapaça apresentando os menores valores (p<0,05). Hipóxia e hipercarbia estimularam o aumento da ventilação nas duas espécies estudadas (p<0,05), sendo observadas maiores alterações da frequência ventilatória e volume corrente em C. carbonarius. Os valores de custo metabólico da ventilação foram baixos devido à uma diminuição no consumo de oxigênio em hipóxia e hipercarbia, indicando depressão metabólica em ambas as espécies ou então o método para calcular esse custo não ser ideal. Ao relacionar os dados de consumo de oxigênio com os de ventilação, verificou-se a possibilidade de shunt cardíaco esquerdo-direito. Será necessário calcular o trabalho mecânico da ventilação a fim de entender melhor a mecânica ventilatória nas duas espécies e posteriormente relacionar os dados de ventilação e custo metabólico da ventilação com os de trabalho mecânico. / Within the class of Reptilia, the order Testudines possesses some exclusive features such as merged ribs and spine and loss of intercostal muscles, preventing costal ventilation. Furthermore, the natural positions exhibited by Testudines, should influence ventilatory mechanics. The aim of this study was to test the influence of different body positions on ventilatory mechanics by measuring static and dynamic compliance and by using open respirometry to analyze the ventilatory pattern and metabolic cost of ventilation in normoxic, hypoxic and hypercarbic exposures in Trachemys scripta e Chelonoidis carbonarius. C. carbonarius showed the lowest values of lung volumes, static and dynamic compliance when compared to T. scripta as well as to other Testudines´s species. Natural positions significantly influenced ventilatory mechanics in both species, with the lowest values found in animals with legs and head retracted into the shell (p<0.05). Hypoxia and hypercarbia stimulated ventilation in both species, with alterations in frequency and tidal volume being greater in C. carbonarius. Estimated metabolic cost of ventilation was low because of a decrease in oxygen uptake during hypoxia and hypercarbia, indicating metabolic depression in both species or that the method used may not be ideal to calculate the metabolic cost of breathing. Relating oxygen uptake data with ventilation data, it may be possible that left-right cardiac shunting occurred. It will be necessary to calculate the mechanic work of breathing to better understand the ventilatory mechanics in both species and relate ventilation data and metabolic cost of ventilation with mechanical work of breathing.

Previous membrane researches undertaken over the years to develop general deadend filtration models made use of an approach that combined all three classical fouling mechanisms, namely, pore blocking, pore constriction and cake filtration. More recently researchers have modified and adapted this modelling approach for a cross flow side-stream membrane bioreactor (MBR) system. Literature also reveals that there have been numerous recent experimental studies conducted on rotating membrane bioreactor (RMBR) systems. Some of these studies have resulted in the creation of RMBR models of the membrane fouling process as well. However, simulation and modelling of the fouling in RMBRs is still a nascent topic to date due to poor understanding and great complexity of the system hydrodynamics involved. Even when models are developed, they are either too complex to be useful at operational level, or not comprehensive enough to express all possible operational scenarios. In many cases they are simply too difficult to calibrate and thus ending up being more suited as research tools rather than for direct process control. As such, further research is required in this area. The research reported in this thesis consists of the development and validation of a RMBR system fouling model that incorporates all three classical fouling mechanisms. This thesis work is divided into two main sections. On top of a literature review that thoroughly describes the background theory and general information on MBRs along with their state of the art, the first section of the thesis also explains the specific methodologies used to accomplish all the main tasks carried out in this research work. The first step of these methodologies involves the setting-up of a rotating MBR system process based upon the FUV-185-A15R Flexidisks membrane module that was developed by Avanti Membrane Technology (USA). This system was used to collect the majority of the data used in this thesis. Since some of these data outputs were compared against non-rotating MBR systems, a similar setting-up process for a bespoke static square MBR system was carried out as well. Using synthetic wastewater in conjunction with activated sludge, mixed liquor suspended solids in both MBR system bioreactors were increased in levels over time to desired levels (i.e. by periodic excess sludge wasting). Trans-membrane pressure (TMP)-stepping fouling data was then acquired from operations of these membrane ultrafiltration processes. This data was obtained by measuring the flux decline or TMP increase. Following data collection, a dynamic fouling model for this RMBR system was then created in Matlab (using the Genetic Algorithm function). To do this, hydrodynamic regimes such as air scouring and rotating shear effects along with all the three classical fouling mechanisms were included in the mathematical fouling model that was created from first principles. For the purpose of comparison, a similar fouling model was created without incorporating the rotational effects for the static square MBR system. This included modelling of the hydrodynamics as well. Finally, both these models were validated and calibrated using the data that were collected from both laboratory-based MBR systems. The second phase of the thesis explores the numerous outputted results produced via model simulations which were then discussed and analysed in great detail. Results from this research indicate that the mathematical models give a decent portrayal and description of the fouling mechanisms occurring within a rotating MBR system. It was found that the rotational mechanisms in terms of fouling prevention accounted for only twelve percent of cake removal with the rest being accomplished through the air scouring mechanism. However, it was found that although the slowly rotating spindle induced a weak crossflow shear, it was still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded, which would lead to dramatic loss of flux. Furthermore, when compared against the static MBR system, the study concluded that a rotating MBR system could increase the flux throughput by a significant amount. In conclusion, RMBR systems appear to represent alternative viable solutions when compared against the traditional static MBR systems that currently dominate the industrial and municipal marketplace. In future, RMBR systems may become the systems of first choice once there is a better understanding of the rotational processes, and once research and design into this sector broadens. Future study areas should thus focus on: whether the forces acting on an activated sludge particle during rotation have a significant effect on the fouling or the shear hydrodynamic regimes; whether activated sludge and benchmark models could be created for rotating MBRs whilst including the shear effects and hydrodynamic regimes; whether model predictive control using these developed RMBR models would enhance efficiency gains within an operational plant; and, whether the real measured soluble microbial products (SMP) concentrations could be used to create an even better SMP predictive model that accurately explains fouling behaviour.

Stationary (static) shoulder friction stir welding (SSFSW) is a variant of conventional friction stir welding (FSW) that was originally invented to improve the quality of welds produced with titanium alloys. Its predominant advantage is a reduction of the severe through thickness temperature gradients seen in conventional FSW, when welding low thermal conductivity alloy. However, SSFSW has rarely been utilised as a method to weld aluminium alloys because it is generally thought that in conventional FSW the rotating shoulder plays an essential role in the heat generation and, due to the high thermal conductivity of aluminium alloys, a rotating shoulder is beneficial for the welding process. In the work presented, the advantages of SSFSW have been examined when welding a typical high strength aluminium alloy AA7050-T7651. The process window for each approach has first been determined, and the optimum welding conditions were systematically evaluated, using power-rotation rate curves. Direct comparison of the two processes was subsequently carried out under these optimum conditions. It has been demonstrated that SSFSW can dramatically improve the quality of a weld's surface finish. Under optimum conditions it has also been shown that SSFSW was able to weld with approximately a 30% lower heat input than FSW and the stationary shoulder led to a narrower heat affected zone (HAZ). As a result, the through thickness properties of SSFSW were much better and more homogeneous than that for FSW, in terms of grain sizes, hardness and cross-weld mechanical properties. Uniaxial tensile tests proved that the average tensile strength of SSFSW samples was around 500 MPa, which was about 100 MPa larger than that of the FSW sample. Also, it was shown that during tensile testing the deformation zones, which correspond to minima in the hardness distribution of SSFSW welds, were about half the size of those found in FSW welds under the same traverse speed. The mechanisms that give rise to these advantages have been investigated systematically, focusing on directly comparing the SSFSW and FSW processes, and are discussed aided by finite element modelling (FEM) of the heat distribution in welds produced by each process and microstructural investigations.

Electrostatic interaction has long been proposed to be an important factor for stabilizing protein. Charge-charge interaction may especially be important to the thermostability of protein, as having more surface electrostatic interactions is one of the common structural features found in thermophilic proteins when compared to their mesophilic homologues. In order to quantitatively investigate the electrostatic contribution to protein stability, two complementary approaches, namely the double mutant cycle approach and pKa shift approach, were carried out. / In the double mutant cycle approach, the coupling free energies of two salt bridges (E6/R92 and K46/E62) and one a long range ion pair (E90/R92) were estimated by using circular dichroism, to find out the thermodynamic parameters of the protein model Thermococcus celer L30e and its charge-to-neutral mutants. It was found that the coupling free energy was temperature independent and was about 3 kJ mol-1 per salt bridge. By using a novel analysis of double mutant cycle of DeltaC p, it was also found that the interaction of salt bridge plays an important role in the reduction of DeltaCp. The temperature independency of coupling free energy and the effect of reducing DeltaCp could explain the general observation very well that thermophilic proteins have highly up-shifted protein stability curves is due to its elevated electrostatic interactions when compared with their mesophilic homologs. / In the pKa shift approach, the native state pKa values of acidic residues were obtained by fitting the side chain carboxyl 13C chemical shifts to microscopic model or global fitting of titrational event (GloFTE), whereas the denatured state pKa values were obtained by conventional pH titration of terminal protected 5-residue glycine-based model peptide. It was found that the surface charge-charge interactions, either attractive or repulsive, were strong and complicated because of the high surface charge density of T. celer L30e. However, the fact that most of the acidic residues have significantly downshifted native state pK a values indicated the surface charge distribution of T. celer L30e is optimized for stabilizing the protein. In addition, we have shown that temperature has negligible effect on pKa values in both native state and denatured state, therefore temperature can only marginally amplify the stabilizing effect in linear manner. / To overcome the unwanted crystallization problem of wild-type T. celer L30e in the low ionic strength neutral pH NMR conditions, which were essential for the pKa shift approach, a quintuple Arg-to-Lys variant was designed to dramatically improve the crystalline solubility, while the surface charges, as well as the structural, thermodynamic, and electrostatic properties, were conserved. It has also shown that electrostatic interaction played a critical role in crystallization at low ionic strength conditions, and arginine residue was especially important in crystal packing because of its high ability of forming salt bridges and hydrogen bonds. / Wild-type T. celer L30e has also shown to have no observable residual structure in the guanidine HC1-induced denatured state, indicating that denatured state of T. celer L30e should not have large effect on the overall protein stability. / Chan, Chi Ho. / Adviser: Kam Bo Wong. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 202-218). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Resumo: Ciclodextrinas (CD) têm sido relatadas em inúmeros estudos por interagir com muitos fármacos para a formação de complexos de inclusão com o objetivo de aumentar a solubilidade, estabilidade e biodisponibilidade. No processo usual para obtenção de comprimidos contendo Beta-CD, as dispersões líquidas de fármaco/Beta-CD são submetidas a processos de secagem por liofilização, evaporação ou spray-drying e o material seco é incorporado a vários excipientes. O objetivo principal deste trabalho foi avaliar processos de obtenção de comprimidos de Beta-CD/paracetamol. O paracetamol foi utilizado como fármaco modelo por ser pouco solúvel em água. No primeiro processo, a dispersão líquida de Beta-CD/paracetamol foi incorporada ao amido de milho, celulose microcristalina ou lactose monoidratada e o material foi granulado e submetido à secagem em leito estático (estufa). No segundo processo, a dispersão líquida de Beta-CD/paracetamol foi incorporada ao amido de milho e o material submetido à secagem em leito fluidizado (leito de jorro). Os materiais obtidos em ambos os processos foram comprimidos. Comparando os três excipientes utilizados no primeiro processo, tanto o amido quanto celulose são os excipientes que possibilitariam a incorporação de quantidade maior de fármaco. Como resultados, os granulados obtidos a partir dos excipientes amido e celulose apresentaram boas características de escoamento e compressibilidade. O segundo processo, originou um material que apresentou boas características de compressibilidade e comprimidos que apresentaram as melhores características físicas durante o processo de compactação. Concluiu-se que ambos processos representam uma estratégia tecnologicamente viável para obtenção de comprimidos contendo Beta-CD. / Abstract: Cyclodextrins (CDs) have been reported in a number of studies in the pharmaceutical field since it interact with many drugs to form water soluble inclusion complexes, thus improving not only the solubility but also the stability and biovailability of various drugs. In order to obtain Beta-CD tablets, liquid dispersions of drug/ Beta-CD are usually submitted to different drying process, like spray drying, freeze-drying or slow evaporation and further added to several excipients. In this work we evaluated different process for the preparation of Beta-CD/ acetaminophen tablets. Due to its low solubility, we have used acetaminophen as a drug model. In the first process, an aqueous Beta-CD/ acetaminophen dispersion were added to corn starch, microcrystalline cellulose or monohydrated lactose and the material was dried in a static bed. In the second process, an aqueous Beta-CD/acetaminophen dispersion were added to corn starch and further dried in a fluidized bed (spouted bed). As a result, in the first process the use of starch or cellulose led to mixtures with higher amount of drug with good flowability and compressibility, whereas the second process led to a mixture of good compressibility and to tablets that presented the best physical proprieties. In conclusion, both process represent viable technological approaches to obtain Beta-CD tablets. / Orientador: Maria Palmira Daflon Gremião / Coorientador: Ana Dóris de Castro / Banca: Leila Aparecida Chiavacci / Banca: Osvaldo de Freitas / Mestre

Os escorregamentos causados por precipitação intensa ocasionam grandes prejuízos a cada estação chuvosa no sudeste brasileiro. Essa dissertação estudou 2 amostras de solos da região serrana do Rio de Janeiro sob uma nova ótica de análise para escorregamentos. As amostras foram coletadas 4 meses após a ocorrência do megadesastre, onde chuvas com precipitação de 325mm em 48 horas causaram mais de 1500 mortes. Em relatos e vídeos obtidos de movimentos de massa que ocorreram nesse evento foi possível observar que o solo apresentou comportamento de um líquido denso e viscoso, escoando pelas encostas da cidade, ou seja, o solo, encharcado pelas chuvas intensas que ocorreram na região, sofreu liquefação. Esse material viscoso formado pela mistura de solo+água que foi caracterizado através da utilização da reologia. Para isso foram apresentados os conceitos da reologia e dos ensaios reométricos, e as possíveis aplicações para solos e na caracterização de corridas de lama. Foram utilizados três ensaios para caracterizar o solo no estado fluido, que foi o squeeze flow, o reômetro de torque com reometria planetária, e o reômetro de placas paralelas. O principal objetivo para utilização desses ensaios é a praticidade para realização dos ensaios, que tem como características: a rapidez na execução, a coleta de dados é realizada automaticamente, apresentam receptibilidade e a facilidade na execução. Com os resultados obtidos foi possível observar a mudança de comportamento do solo (de um material com comportamento elástico para um material como um fluxo de lama) com a elevação da umidade, para os dois ensaios. Os resultados demonstram que o valor do limite de liquidez calculado através do aparelho de Casagrande é confirmado com esses novos aparelhos, ii sendo que, para esses aparelhos é visível a mudança de comportamento que define o limite de liquidez. Através dos resultados também foi possível determinar que o solo em estado fluido tem seu comportamento regido pelo modelo de Herschel Bulkley. Para tornar os resultados obtidos aplicáveis foi apresentado um capítulo ligando os resultados obtidos da reometria com a possibilidade do solo sofrer liquefação, aliado com os resultados obtidos dos ensaios de caracterização geotécnica. Sendo realizadas análises de estabilidade com os resultados obtidos, correlacionando a inclinação do talude, o nível dágua e a ocorrência da liquefação. / Landslide caused by rainfalls cause major damage each rainy season in southeastern Brazil. This dissertation studied two soil samples from the mountainous region of Rio de Janeiro in a new light analysis for landslides. Samples were collected four months after the occurrence of disaster, when rainfall with intensity of 325mm in 48 hours caused more than 1,500 deaths. In reports and video obtained from mass movements that occurred at this event was observed that the soil responded as a dense liquid, viscous draining the citys landscape. The drenched soil, by heavy rains that occurred in the region, suffered liquefaction. This viscous material formed by mixture of soil and water that was characterized by the use of rheology. In this dissertation was presented the concepts of rheology and rheometric tests for application in soils and characterization of fluid movements. Tree different rheometric tests were performed to characterize the soil in the fluid state, which was the squeeze flow, torque rheometer with planetary geometry and parallel plate rheometer. The main objective of these tests is to use the convenience for the tests, that presents the follow characteristics: the speed of execution, data collection is performed automatically and the testes present repeatability apart from ease of application. With the results we observed the change of soil behavior (of a material with elastic properties for a material that presents the behavior as a mud flow) with increasing humidity for the tests. The results show that the value of the liquidity limit calculated by the Casagrande apparatus is confirmed with these new devices, furthermore with the use of these devices is visible the behavior change that defines the liquid limit. iv Was determined that the Herschel Bulkley model is the one that best represents the behavior of the soil in the fluid state. Was presented a chapter with an application of the results obtained by adding the results of the rheometer with the results of geotechnical characterization tests to determine the possibility of soil suffer liquefaction. To this aim, were performed stability analysis considering the results obtained, correlating the slope inclination, the water level and the occurrence of liquefaction.

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-10-01T11:08:04Z No. of bitstreams: 2 Dissertação - Adriane Barbosa Gomide - 2013.pdf: 1351297 bytes, checksum: 7345fc7d8a1ef694167b6aba1bf83c01 (MD5) license_rdf: 23748 bytes, checksum: b92763cfc0af52c7c868455edfaf3266 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-10-01T15:23:32Z (GMT) No. of bitstreams: 2 Dissertação - Adriane Barbosa Gomide - 2013.pdf: 1351297 bytes, checksum: 7345fc7d8a1ef694167b6aba1bf83c01 (MD5) license_rdf: 23748 bytes, checksum: b92763cfc0af52c7c868455edfaf3266 (MD5) / Made available in DSpace on 2014-10-01T15:23:32Z (GMT). No. of bitstreams: 2 Dissertação - Adriane Barbosa Gomide - 2013.pdf: 1351297 bytes, checksum: 7345fc7d8a1ef694167b6aba1bf83c01 (MD5) license_rdf: 23748 bytes, checksum: b92763cfc0af52c7c868455edfaf3266 (MD5) Previous issue date: 2013-09-27 / Introduction: The usual physiological and biomechanical changes during aging lead to the appearance of pain in different places, in addition to musculoskeletal disorders and to increased instability in posture maintenance, which increases the risk of falling off. Objectives: the aim of this study was to evaluate the efficiency of the proprioceptives insoles in tonic postural equilibrium and reprogramming postural of the elderly. Methods: In this work, were evaluated 19 elderly, one evaluation was done before use proprioceptives insoles and one revaluation was done 3 months after the begin of the use of the insoles. It was traced, initially, the antropometric and sociodemographic profile of elderly and a Visual Analogic Scale was applied to evaluate the pain before and after the use. Thereafter, were submitted an evaluation to the posturology in the sagittal, frontal and horizontal plan for the best option of the insoles for each volunteer. Then, all elderly performed three trials in which they maintained a quasi-static posture lasting 60 s in each trial, both with open and closed eyes. Were analyzed arrows of sagittal plan variables – envelope occipital arrow (OCC), cervical arrow (CA), lumbar arrow (LA) and gluteo plan (PG) – and stabilometric variables – 80% power frequency (F80), root mean square (RMS), and mean velocity (MV), both for the anteroposterior (AP) and mediolateral (ML) displacements of the pressure center (COP), and the COP area. Results: The pain evaluated by EVA had a significant improvement, although as the evaluations performed in the sagittal plane for the variables OCC, CA and PG. There wasn’t found significant difference before and after the use of the insoles in condition of OA. By the way, in condition of OF, a significant improvement was observed in the variables RMS ML and MV ML. In comparison between OA and OF before of the use of proprioceptive insoles, it was observed significant differences in the following variables: F80, AP; RMS AP; MV AP; and COP area, however, after use of insoles the difference was significant only F80ML and MV ML. Conclusion: The use of proprioceptive insoles had significant influence in the improvement of the pain frame and static posture, mainly in the sagittal plane. When the visual information was withdrawn after the use of the insole, there wasn’t difference in several significant variables. This could suggest that the use of insoles promoted an improvement of the results in tonic postural balance of elderly. / Introdução: As alterações fisiológicas e biomecânicas comuns durante o envelhecimento levam ao surgimento de algum quadro álgico, além de desordens posturais e instabilidade da manutenção da postura ereta quasiestática, isso pode aumentar risco de quedas. Objetivo: Avaliar a eficiência das palmilhas proprioceptivas no equilíbrio tônicopostural e na reprogramação da postura dos idosos. Metodologia: Neste estudo foram avaliadas 19 idosas, sendo feita uma avaliação antes do uso das palmilhas proprioceptivas e uma reavaliação após 3 meses de uso das palmilhas. Inicialmente, foi traçado o perfil antropométrico e sociodemográfico das idosas, sendo aplicada a Escala Visual Analógico (EVA) para avaliar a dor antes e após o uso, por conseguinte, foram submetidas a uma avaliação da postura, sendo avaliadas nos planos sagital, frontal e horizontal para melhor escolha da palmilha para cada participante. Em seguida, foram submetidas à tarefa de manutenção da postura ereta quasi-estática, em três ensaios distintos, cada um com a duração de 60s, tanto com olhos abertos (OA) quanto com olhos fechados (OF). Foram analisadas as variáveis das flechas formadas no plano sagital – flecha occipital (OCC), flecha cervical (FC), flecha lombar (FL) e plano glúteo (PG) – e estabilométricas – frequência de 80% (F80), valor quadrático médio (RMS, do inglês Root Mean Square) e velocidade média (VM), tanto para deslocamentos do centro de pressão (COP) nas direções ântero-posterior (AP) quanto médio-lateral (ML), e área do COP. Resultados: As dores avaliadas pela EVA tiveram uma melhora significativa, assim como a avaliação realizada no plano sagital para as variáveis OCC, FC e PG. Não foi encontrada diferença significativa antes e após o uso das palmilhas na condição de OA. Já na condição de OF, foi observado melhora significativa das variáveis RMS ML e VM ML. Na comparação entre OA e OF antes do uso das palmilhas proprioceptivas, foram observadas diferenças significativas para as seguintes variáveis estabilométricas: F80 AP; RMS AP; VM AP; e Área do COP, no entanto, após o uso das palmilhas ocorreu diferença significativa apenas F80ML e VM ML. Conclusão: O uso da palmilha proprioceptiva teve influência significativa na melhora do quadro álgico e na postura estática, principalmente no plano sagital. Ao retirarmos a informação visual após o uso da palmilha, não houve diferença significativa em diversas variáveis, pode-se sugerir que o uso das palmilhas promoveu melhora dos resultados no equilíbrio tônico postural das idosas.

Este trabalho trata da retificação trifásica com elevado fator de potência. São mostradas algumas soluções encontradas na literatura. Dentre elas, optou-se pela utilização de um conversor trifásico autocomutado do tipo fonte de tensão (VSC), operando em modulação em largura de pulso (PWM). Apresenta-se a modelagem do conversor, que é utilizado para o projeto dos controladores responsáveis pelo rastreamento das correntes da rede CA e pela regulação da tensão CC. O projeto do controlador das correntes CA, baseado na estratégia de dead-beat, é mostrado de forma simples e intuitiva e é discutida a estabilidade deste controlador. O projeto do controlador PI utilizado para a regulação da tensão CC é baseado no modelo linearizado do conversor. É utilizado um algoritmo simples e eficiente para o bloco PLL, baseado na estratégia “dead-beat”. O comportamento do sistema completo é verificado teoricamente, por simulações numéricas e resultados experimentais, confirmando o excelente desempenho das estratégias de controle e do método de projeto propostos. São discutidos ainda os efeitos da variação nos parâmetros no desempenho e na estabilidade do sistema. / This study investigates three-phase rectifiers with high power factor. Some existing solutions in the literature are presented. One of them, the three-phase voltage source converter (VSC) rectifier with pulse width modulation (PWM) is chosen to be used. Converter modeling is presented and used to design a mains current tracking controller and a DC voltage regulator. AC current controlling based on the deadbeat strategy is presented in a simple and intuitive way, and the stability of this controller is discussed. The DC side PI controller is designed based on the linearized model of the converter. A simple and efficient PLL block algorithm, based on the deadbeat strategy is presented. The behavior of the complete system is verified theoretically, by numerical simulation and experimental results, confirming the excellent performance of the proposed control strategy and method of design. The effects of parameter mismatch on system performance and stability are also discussed.

Para proporcionar menores prazos e custos, o projeto de ampliação da sede da Petrobras, na cidade de Salvador, estado da Bahia, contemplou estacas barretes de grandes dimensões para grandes capacidades de carga. Porém, para atingir as cargas escolhidas, foi necessário embutir as estacas no topo rochoso. Portanto, foram projetadas estacas barretes embutidas em rocha, escavadas com hidrofresa. Esta pesquisa apresenta o estudo de duas provas de carga estáticas executadas em uma mesma estaca barrete teste embutida em rocha, a fim de proporcionar um melhor entendimento de seu comportamento, assim como os principais fatores que influenciam resistência e deformabilidade. Em março de 2012, foram realizadas duas provas de carga estáticas na mesma estaca barrete teste embutida em rocha. Os ensaios foram executados a partir das metodologias normativas NBR 12131 (2006) e NBR 6122 (2010), com carregamentos lento e rápido, respectivamente e subsequentemente. No primeiro ensaio (lento), aplicou-se a carga máxima de 12 MN, enquanto que no segundo (rápido), aplicou-se a carga máxima de 14 MN. Os dados obtidos nos ensaios, de acordo com a bibliografia utilizada, são pioneiros no Brasil, por se tratar da primeira estaca barrete embutida em rocha com utilização de hidrofresa, submetida à prova de carga de desempenho. A estaca foi instrumentada em profundidade, o que propiciou a avaliação da distribuição de carga nas camadas atravessadas. Foram realizadas comparações entre resultados obtidos da instrumentação e do topo, por meio do repique elástico. Além da avaliação e interpretação dos dados obtidos nos ensaios de provas de carga estáticas, esta pesquisa apresenta previsões de comportamento, com diferentes conceitos, para estacas embutidas em rocha, sem reação de ponta, com intuito de comparar seus resultados com os obtidos nos ensaios. Em conjunto com as previsões, foram apresentados métodos para estimativa de adesão lateral na interface da estaca com o maciço rochoso. / To use high loads on foundations of the Petobras Headquarters, the designers chose the barrette pile with great dimensions and a few units compared with others types, to shorten the deadline and optimize costs. However, to reach these assumptions, it was necessary make the piles deeper than the soil strata, and, therefore, made a rock socket design. This research presents two static load tests study and analysis in the same barrette test pile, to forecast behavior and find resistance and strain influences. In March, 2012, two static load tests were made in the same barrette test pile located in Salvador Bahia, in Petrobras headquarters. The first essay was made according to a slow maintained test with 12 MN maximum compressive loads. The second essay was made immediately after, according to a quick load test and 14 MN maximum compressive loads. The data obtained from both tests, far as is known, were the first results on rock socket barrette pile in Brazil, using hydromill for the excavations in rock. The pile had depth instrumentation with expansible strain gages and an expanded polystyrene block below the cage, to make the tip useless. Beyond the data assessment and interpretation from static load tests, this research presents forecasting methods to only shear resistance rock socket piles, with the aim of comparison. Lastly but not least, side resistance empirical methods between pile and rock interface were presented.

<p>Cilj ovog rada je ispitivanje uticaja procesnih<br />parametara (transmembranski pritisak, protok i<br />koncentracija suspenzije) na vrednost fluksa<br />permeata, sa i bez prisustva statičkog me&scaron;ača,<br />tokom procesa mikrofiltracije suspenzija<br />p&scaron;eničnog skroba na keramičkim membranama<br />različitih veličina pora (200 nm i 500 nm).<br />Mikrofiltracija je izvođena u uslovima<br />recirkulacije i koncentrisanja napojne suspenzije.<br />Za modelovanje zavisnosti procesa mikrofiltracije<br />suspenzija skroba od procesnih parametara<br />primenjen je postupak odzivne povr&scaron;ine.<br />Ispitivanjem mikrofiltracije suspenzija p&scaron;eničnog<br />skroba na membranama sa različitim srednjim<br />prečnikom pora (200 i 500 nm) uočeno je da sa<br />povećanjem veličine pora vrednost fluksa<br />permeata opada.<br />U posmatranom eksperimentalnom opsegu<br />procesnih parametara postignuto je relativno<br />povećanje stacionarnog fluksa od 25% do 50% u<br />uslovima recirkulacije napojne suspenzije, dok je<br />u uslovima koncentrisanja napojne suspenzije<br />relativno povećanje srednjeg fluksa iznosilo od<br />20% do 80%. Porast fluksa do kojeg dolazi<br />postavljanjem statičkog me&scaron;ača u kanal membrane</p><p>uslovljen je uspostavljanjem turbulentnih uslova<br />proticanja i karakterističnog kretanja fluida duž<br />kanala membrane, koja je posledica<br />karakterističnog povezivanja helikoidnih<br />elemenata Kenics statičkog me&scaron;ača.<br />Kako u uslovima recirkulacije napojne sme&scaron;e,<br />tako i u uslovima koncentrisanja, vrednost<br />relativne specifične potro&scaron;nje energije zavisi skoro<br />isključivo od vrednosti protoka napojne sme&scaron;e. Sa<br />povećanjem protoka specifična potro&scaron;nja energije<br />u prisustvu statičkog me&scaron;ača naglo raste i<br />relativno povećanje protoka nije dovoljno da bi<br />kompenzovalo gubitak hidrauličke snage. U<br />opsegu protoka od 80 do 100 L/h su obezbeđene<br />pozitivne vrednosti relativne promene specifične<br />potro&scaron;nje energije, te je upotreba statičkog me&scaron;ača<br />opravdana sa ekonomskog aspekta.<br />Optimizacija eksperimentalnih uslova urađena je<br />postupkom istovremene maksimizacije fluksa<br />permeata u sistemima sa statičkim me&scaron;ačem i<br />relativne promene specifične potro&scaron;nje energije.<br />Optimalni uslovi izvođenja procesa mikrofiltracije<br />suspenzija p&scaron;eničnog skroba u uslovima<br />recirkulacije napojne suspenzije ukazuju da je<br />proces potrebno izvoditi pri maksimalnoj<br />vrednosti transmembranskog pritiska od 0,9 bara,<br />protocima od 85 do 100 L/h i koncentraciji od 5<br />do 6 g/L.<br />Optimalni uslovi izvođenja procesa mikrofiltracije<br />suspenzija p&scaron;eničnog skroba u uslovima<br />koncentrisanja napojne suspenzije ukazuju da je<br />proces potrebno izvoditi pri vrednosti<br />transmembranskog pritiska od 0,85 do 0,9 bara,<br />protocima od 85 do 100 L/h i koncentraciji od 5<br />do 7 g/L.<br />Pored ispitivanja na laboratorijskoj<br />aparaturi, cilj ovog rada je bio i ispitivanje uticaja<br />procesnih parametara na proces mikrofiltracije<br />suspenzija skroba u poluindustrijskim uslovima<br />(na jednokanalnoj i vi&scaron;ekanalnoj membrani<br />srednjeg prečnika pora 200 nm), odnosno &scaron;ireg<br />opseg vrednosti transmembranskog pritiska i<br />protoka suspenzije na pomenute odzive u<br />uslovima koncentrisanja napojne suspenzije.</p> / <p> The aim of this study was to investigate the effect of<br /> process parameters (transmembrane pressure, flow<br /> rate and suspension concentration) on the permeate<br /> flux in the system with and without the presence of<br /> static mixer. Microfiltration of wheat starch<br /> suspensions was performed in recirculation and<br /> concentration mode using ceramic membranes with<br /> different pore size (200 nm and 500 nm). Response<br /> surface methodology was applied for modeling<br /> cross-flow microfiltration of starch suspensions.<br /> During investigation of starch suspension<br /> microfiltration process on membranes with different<br /> pore size diameter (200 and 500 nm) it was<br /> observed that with increasing pore size the permeate<br /> flux declined.<br /> In the experimental range of process parameters,<br /> flux increase had values between 25% and 50% in<br /> recirculation mode, while in concentration mode<br /> this improvement was in range between 20% and 80%. The increase in flux that occurs by placing a</p> <p> static mixer in the membrane channel was caused<br /> by the establishment of turbulent flow conditions<br /> and the characteristic flow of fluid along the<br /> membrane channel, which is a consequence of the<br /> characteristic geometry of Kenics static mixer.<br /> Both in recirculation and concentration mode, the<br /> reduction of specific energy consumption depends<br /> almost exclusively on the value of the suspension<br /> flow rate. Specific energy consumption increased<br /> rapidly with increasing flow rate in the presence of<br /> static mixers and flux improvement is not high<br /> enough to compensate the loss of hydraulic<br /> dissipated power. The flow rate in the range from<br /> 80 to 100 L/h provided positive values of the<br /> reduction of specific energy consumption and the<br /> use of static mixers was justified from the<br /> economical point of view.<br /> Optimization of experimental conditions was done<br /> by a procedure of simultaneous maximization of<br /> permeate flux in systems with static mixers and<br /> reduction of specific energy consumption. Optimal<br /> conditions of the wheat starch suspension<br /> microfiltration in recirculation mode indicate that<br /> the process should be conducted at the maximum<br /> value of transmembrane pressure of 0.9 bar, flow<br /> rates from 85 to 100 L/h and concentration of 5 to 6<br /> g/L.<br /> Optimal conditions of the wheat starch suspension<br /> microfiltration in concentration mode indicate that<br /> the process should be conducted when the value of<br /> transmembrane pressure from 0.85 to 0.9 bar, flow<br /> rates from 85 to 100 L/h and concentration of 5 to 7<br /> g/L.<br /> Apart from investigations in laboratory conditions,<br /> the aim of this study was to examine the influence<br /> of process parameters on the starch suspensions<br /> microfiltration in the pilot plant (one channel and<br /> multichannel membrane with pore diameter 200<br /> nm) and wider range of transmembrane pressure<br /> and suspension flow rate on the mentioned<br /> responses in concentration mode.</p>