292 resultados para Retificadores de corrente eletrica
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The State of Paraíba is one of the most dynamic states of Brazil, strategically located in the northeast, is notable for the excellent potential for integration of different transportation modes forming the states of Rio Grande do Norte, Pernambuco and Alagoas. The dynamic that occurs with port activity causes changes in the space where it is installed. And the elements of this space are always more than suffering direct or indirect influences as the flow in the port is expanded. Therefore, this region became subject to the accidental spillage of oil, because it presents a heavy traffic of ships of various sizes that can run aground or collide with oil causing accidental events. The study of geomorphological and sedimentological compositions of seafloor becomes important as more is known about the relationships between these parameters and associated fauna, and can identify their preferred habitats. The database background, acoustically collected along the proposed study area, is a wealth of information, which were duly examined, cataloged and made available. Such information can serve as an important tool, providing a geomorphological survey of the sedimentary area studied, and come to subsidize, in a flexible, future decision making. With the study area Port of Cabedelo, Paraíba - Brazil, this research aimed to evaluate the influence of the tidal surface and background in modeling the seabed, including the acquisition of information about the location of submerged rocky bodies and the depth of these bodies may turn out to be natural traps for the trapping of oil in case of leaks, and obtain the relationship between types of bed and the hydrodynamic conditions present in the region. In this context, for this study were collected bathymetric data (depth) and physical oceanographic (height of water column, water temperature, intensity and direction of currents, waves and turbidity), meteorological (rainfall, air temperature, humidity, winds and barometric pressure) of the access channel to the Port of Cabedelo / PB and its basin evolution (where the cruise ships dock), and includes tools of remote sensing (Landsat 7 ETM +, 2001), so that images and the results are integrated into Geographic Information Systems and used in the elaboration of measures aimed at environmental protection areas under the influence of this scale facilities, serving as a grant to prepare a contingency plan in case of oil spills in the region. The main findings highlight the techniques of using hydroacoustic data acquisition together bathymetric surveys of high and low frequency. From there, five were prepared in bathymetric pattern of Directorate of Hydrography and Navigation - DHN, with the depth in meters, on a scale of 1:2500 (Channel and Basin Evolution of Access to Port of Cabedelo), where there is a large extent possible beachrocks that hinder the movement of vessels in the port area, which can cause collisions, running aground and leaking oil. From the scatter diagram of the vectors of currents, it can be seen as the tidal stream and undergoes a channeling effect caused by the bidirectional effect of the tide (ebb and flood) in the basin of the Port of Cabedelo evolution in NW-direction SE and the highest speed of the currents occurs at low tide. The characterization weather for the period from 28/02 to 04/07/2010 values was within the expected average for the region of study. The multidisciplinary integration of products (digital maps and remote sensing images), proved to be efficient for the characterization of underwater geomorphological study area, reaching the aim to discriminate and enhance submerged structures, previously not visible in the images
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Ionic liquids (ILs) are organic compounds liquid at room temperature, good electrical conductors, with the potential to form as a means for electrolyte on electrolysis of water, in which the electrodes would not be subjected to such extreme conditions demanding chemistry [1]. This paper describes the synthesis, characterization and study of the feasibility of ionic liquid ionic liquid 1-methyl-3(2,6-(S)-dimethyloct-2-ene)-imidazole tetrafluoroborate (MDI-BF4) as electrolyte to produce hydrogen through electrolysis of water. The MDI-BF4 synthesized was characterized by thermal methods of analysis (Thermogravimetric Analysis - TG and Differential Scanning Calorimetry - DSC), mid-infrared spectroscopy with Fourier transform by method of attenuated total reflectance (FTIR-ATR), nuclear magnetic resonance spectroscopy of hydrogen (NMR 1H) and cyclic voltammetry (CV). Where thermal methods were used to calculate the yield of the synthesis of MDI-BF4 which was 88.84%, characterized infrared spectroscopy functional groups of the compound and the binding B-F 1053 cm-1; the NMR 1H analyzed and compared with literature data defines the structure of MDI-BF4 and the current density achieved by MDI-BF4 in the voltammogram shows that the LI can conduct electrical current indicating that the MDI-BF4 is a good electrolyte, and that their behavior does not change with the increasing concentration of water
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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In this study, it has been investigated the influence of silver film deposition onto 100% polyester woven and non-woven, on the survival of Escherichia coli and Staphylococcus aureus in contact with these surfaces. The treatment was performedin a chamber containing the working gas at low pressure (~ 10-2 mbar). Some process parameters such as as voltage: 470 V; pressure: 10-2 mbar; current : 0.40 A and gas flow: 6 and 10 cm3/min were kept constant. For the treatments with purêargon plasma using a flow of 6 and 10 cm3/min, different treatment times were evaluated, such as, 10 , 20, 30, 40, 50 and 60 minutes. Contact angle (sessile drop), measurements were used to determine the surface tension of the treated fabrics and its influence on the bacteria grow as weel as the possibilities of a biofilm formation. The formation of a silver film, as well as the amount of this element was verified byEDX technique. The topography was observed through scanning electron microscopy (SEM) to determine the size of silver grains formed on the surfaces of the fabric and assess homogeneity of treatment. The X-ray diffraction (XRD) was used to analyze the structure of silver film deposition. The woven fabric treatments enabled the formation of silver particulate films with particle size larger than the non-woven fabrics. With respect to bacterial growth, all fabrics were shown to be bactericidal for Staphylococcus aureus (S. aureus), while for the Escherichia coli (E. coli), the best results were found for the non-woven fabric (TNT) treated with a flow of 10 cm3/min to both bacteria
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This work proposes a model to investigate the use of a cylindrical antenna used in the thermal method of recovering through electromagnetic radiation of high-viscosity oil. The antenna has a simple geometry, adapted dipole type, and it can be modelled by using Maxwell s equation. The wavelet transforms are used as basis functions and applied in conjunction with the method of moments to obtain the current distribution in the antenna. The electric field, power and temperature distribution are carefully calculated for the analysis of the antenna as electromagnetic heating. The energy performance is analyzed based on thermo-fluid dynamic simulations at field scale, and through the adaptation in the Steam Thermal and Advanced Processes Reservoir Simulator (STARS) by Computer Modelling Group (CMG). The model proposed and the numerical results obtained are stable and presented good agreement with the results reported in the specialized literature
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
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Currently, computational methods have been increasingly used to aid in the characterization of molecular biological systems, especially when they relevant to human health. Ibuprofen is a nonsteroidal antiinflammatory or broadband use in the clinic. Once in the bloodstream, most of ibuprofen is linked to human serum albumin, the major protein of blood plasma, decreasing its bioavailability and requiring larger doses to produce its antiinflamatory action. This study aimes to characterize, through the interaction energy, how is the binding of ibuprofen to albumin and to establish what are the main amino acids and molecular interactions involved in the process. For this purpouse, it was conducted an in silico study, by using quantum mechanical calculations based on Density Functional Theory (DFT), with Generalized Gradient approximation (GGA) to describe the effects of exchange and correlation. The interaction energy of each amino acid belonging to the binding site to the ligand was calculated the using the method of molecular fragmentation with conjugated caps (MFCC). Besides energy, we calculated the distances, types of molecular interactions and atomic groups involved. The theoretical models used were satisfactory and show a more accurate description when the dielectric constant ε = 40 was used. The findings corroborate the literature in which the Sudlow site I (I-FA3) is the primary binding site and the site I-FA6 as secondary site. However, it differs in identifying the most important amino acids, which by interaction energy, in order of decreasing energy, are: Arg410, Lys414, Ser 489, Leu453 and Tyr411 to the I-Site FA3 and Leu481, Ser480, Lys351, Val482 and Arg209 to the site I-FA6. The quantification of interaction energy and description of the most important amino acids opens new avenues for studies aiming at manipulating the structure of ibuprofen, in order to decrease its interaction with albumin, and consequently increase its distribution
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O baço, como maior órgão linfóide do corpo humano, desempenha funções imunológicas relevantes, tais como depuração de bactérias da corrente sangüínea, produção de anticorpos e interação com a função hepática. A esplenectomia tem sido evitada sempre que possível, mas quando realizada pode provocar uma série de efeitos indesejáveis. O radiofármaco 99mTc-fitato é usado no diagnóstico de doenças, especialmente no fígado, através de exames de imagem, na dependência de sua biodistribuição. Algumas drogas e intervenções cirúrgicas podem interferir na biodistribuição de radiofármacos e inexistem na literatura dados sobre efeitos da esplenectomia no metabolismo do 99mTc-fitato. O objetivo do trabalho foi avaliar se a esplenectomia interfere na biodistribuição hepática do 99mTc-fitato e na função do fígado em ratos Wistar. Sob anestesia e técnica asséptica, os animais do grupo SP (n=6) foram esplenectomizados. No grupo C (controle; n=6) os animais não foram operados. Após 15 dias de observação, foi injetado de 0,1ml de 99mTc-fitato via plexo orbital (0,66MBq) em todos os animais. Após 30 minutos, foram retiradas amostras hepáticas para determinação do percentual de radioatividade/grama (% ATI/g), usando-se contador gama Wizard Perkin-Elmer. Realizou-se dosagem sérica de ALT, AST e LDH, e leucometria. Estatística pelo teste t, com significância de p>0,05. Observou-se diferença significativa (p=0,034) comparando-se o %ATI/g no fígado dos ratos esplenectomizados (0,990,2) com os controles (0,400,2). ALT, AST e LDH tiveram dosagens significativamente menores e houve leucocitose nos esplenectomizados (p=0,01), comparando-se com os controles. Concluiu-se que, em ratos, a esplenectomia provavelmente provocou alteração na captação de 99mTc-fitato pelo fígado, coincidindo com alterações na função hepática. A realização deste estudo teve caráter multidisciplinar, envolvendo pesquisadores de diversas áreas como Medicina Nuclear, Cirurgia, Análises Clínicas e Estatística. Este aspecto preencheu os requisitos da multidisciplinaridade do Programa de Pós-graduação em Ciências da Saúde
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The neoliberalism proclaims the crisis of the State in front of globalization , but, approaching two books taken as basic on this theoretical chain - The road to serfdom, of Friedrich Hayek, and Capitalism and Freedom, of Milton Friedman - to analyze this supposed dualism, the conclusion into which we arrive is another one. Remembering liberal tradition and quickly, later, analyzing critically the workmanships, can be perceived that others are the conflicts really gifts in the current capitalist reality - market versus State et capitalism versus democracy - and, from the understanding on the reading made and the theoretical trajectory of its authors, we may see as the neoliberalism locates itself in relation to these conflicts, which polar regions of these antagonisms privileges, what represents the State for itself, and what it intends as much more global philosophy than economic/politics thinking only
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In the first half of the twentieth century different groups of intellectuals were engaged in the pursuit of an ideal of Brazility. Thereon, two currents are perceived. The first was marked by a nostalgic bias about the past, being formulated by intellectuals from the region that was turning as Northeast. This group of intellectuals emphasized values and traditions of the agrarian aristocracy of the region that was losing visibility in the political and economic Brazil scene. Already the other current has a more modern and industrial feature, was formed by intellectuals from the Southeast that in detriment of the first, was rising. This group, on the other hand, was intended to give a new face to Brazil and break with the "roots" of our delay that in their view were linked to our agrarian past. This resulted in different perceptions and interpretations of our historical past, and the construction of different profiles to the Brazilian. Accordingly, our work seeks to understand how was produced the writing that silenced the mixed ancestry of Auta de Souza (1876-1901) considering the position that she should occupy in the intellectuals projects who were in charge of forming a memory for our state. Auta as a relevant historical character in this project of potiguares intellectuals, she was raised to the condition of a model woman and elected in the pantheon of the most beloved poets of Rio Grande do Norte, however, to occupy such prestigious position she had her racial ancestry concealed in the writings that these same intellectuals had written about her, what is still spreaded in memory and rituals places of religious and civic features
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O objetivo do trabalho é propor um estudo sobre a relação do Programa Nacional de Crédito Fundiário - PNCF, no estado do Rio Grande do Norte, e sua concentração fundiária. Ou seja, se o PNCF está sendo direcionado, para as microrregiões que apresentam maior índice de concentração, de acordo com o índice de Gini, e se as áreas adquiridas através do crédito fundiário estão emergindo nestas microrregiões. Para isto, o estudo levantou a hipótese de que o PNCF no estado do Rio Grande do Norte não está sendo conduzida, de modo a reduzir a concentração fundiária, dentre as microrregiões do estado. Ou seja, não existe correlação entre o índice de Gini, da concentração fundiária, e as áreas adquiridas através do programa. Além disso, o trabalho buscou realizar uma discussão da literatura sobre os programas de reforma agrária assistida pelo mercado. Apresentando os autores que são exaltadores do modelo e das suas potencialidades, atrelando as causas dos problemas levantados como sendo de ordem técnica e operacional, onde os principais autores desta linha são: Van Zyl, Kirsten & Binswanger, (1996), Deininger & Binswanger, (1999). Têm-se também a apresentação da posição dos autores adeptos as políticas fundiárias pautadas na dinâmica e liberação dos mercados de terras, mas que visam contribuir com estudos que permitam uma redução para o custo elevado e a sua incapacidade de abarcar a esfera social, em decorrência do pagamento á vista e a preço de mercado aos donos das terras, são eles: De Janvry & Sadoulet (2002), Gordillo (2002), Banerjee (1999), Jaramillo (1998) e Burki & Perry (1997). Todavia, apresentou-se a corrente de autores que ressalta a natureza socialmente agressiva da Reforma Agrária Assistida pelo Mercado (RAAM), sendo os seus principais contribuidores: El-Ghonemy (2001); Barros, Schwartzman & Sauer (2003); Borras Jr. (2006, 2003 e 2003a); Garoz et al. (2005); Sauer & Pereira (2006); Pereira (2005, 2006 e 2010); Sauer (2010); Lahiff, Borras Jr. & Kay (2007). Em sequência, o trabalho apresentou a transição e características dos programas de acesso à terra, no Brasil, a partir da década de 1990, bem como, alguns indicadores do PNCF, no Brasil e o estado do Rio Grande do Norte. Apresentou-se também os indicadores da concentração fundiária, no Brasil e no estado. Através dos dados do Censo Agropecuário de 2006 foi possível calcular o índice de Gini da distribuição fundiária nas microrregiões no estado do Rio Grande do Norte. Com os dados fornecidos pela Secretaria de Estado de Assuntos Fundiários e de Apoio à Reforma Agrária - SEARA mostrou-se a distribuição das linhas de crédito do PNCF e as áreas adquiridas, entre os anos de 2006 e 2012. Por fim, o valor do coeficiente de correlação simples (r) igual a (0,2865), que com base no teste bilateral da distribuição de t de Student chegou-se no resultado para T calculado no valor de (1,2333), que ao ser comparado com o valor de T crítico igual a (2,898), com 17 graus de liberdade, a um nível de significância de 1%, pode aceitar a hipótese de partida, ou seja, que o PNCF não estava sendo direcionado para diminuir a concentração fundiária no estado
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On analyse une expérience de l enseignement de philosophie dans l enseignement secondaire par la littérature. La scène d intervention a été l Institut Fédéral d Éducation, Science et Technologie du Rio Grande do Norte (IFRN), dans l année 2008. L étude à caractère qualitatif a adopté un modèle de recherche participant, dans laquelle le chercheur a intervenu dans son propre contexte de classe. On a utilisé l investigation d un ouvrage existentialiste de Jean-Paul Sartre, le roman La Nausée, comme contribution méthodologique pour l enseignement de philosophie. On a adopté le recours de la littérature avec contenu philosophique à partir de la proposition apportée para les Paramètres Curriculaires Nationaux pour l Enseignement Secondaire (PCNEM) : celle qu on ne doit ni avoir la prétention de former de philosophes professionnels ni banaliser la philosophie auprès des élèves. En partant du principe que l existentialisme a été un courant philosophique qui a utilisé la littérature entant qu expression d idées philosophiques, on a envisagé le potentiel pédagogique du voisinage communicant entre la philosophie et la littérature que lie l expérience littéraire avec les textes qui montrent aussi la discussion philosophique. L idée force a été celle de traiter concepts philosophiques a partir de la littérature comme invitation à la réflexion, en analysant l élément ludique dans la littérature comme jeu de la pensée. La pensée considérée comme action ludique arriverait parmi l idéal d en chercher de meilleures manières à comprendre la réalité en étant cet idéal esthétique assumé dans l effort d imprimer sens au chaos des expériences. Les situations pédagogiques en classe comptent fréquemment avec moment de dialogue a propos des problèmes existentiels affrontés par le protagoniste du roman, Antoine Roquentin, considérés comme questions philosophiques et débattues par l investigation dialogique tout suite après la lecture des parties du livre. Dans ce sens, on a cherché à suivre les marches de la méthode socratique dans lequel questionner e questionner à soi même soient les moles propulseurs de la réflexion philosophique. L investigation dialogique a été étendue pendant cinq rencontres de quatre-vingt-dix minutes interprétés par une analyse discursive qui a essayé d établir des rapports entre le discours de l enseignant et des élèves avec le discours de la tradition philosophique. Cette recherche a aussi envisagé à produire une réflexion sur la pratique de l auteur lui-même de l étude. Celui-ci peut-être soit l objectif le plus largement atteint : prendre conscience de l importance de la formation d un enseignant réflexif qui associe dans sa praxis le savoir faire avec la critique honnête de sa propre capacité professionnel
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A modeling of criterias and alternatives is through and applied a questionnaire based on method AHP to proprietors of gas stations. The considered alternatives had been the maintenance of the current state with electric energy of the deliverer and the generation in small scale based on the natural gas. The used criteria had been Cost of the Investment, Final Cost of the Energy, Operational cost, Ambient Benefits, Risk and Variation of Costs. The study it was carried through in the city of Natal, RN in ranks that make use of the natural as for resale, where the generation alternative on the basis of the available gas is present. The main results evidence in a dimension the viability of use of method AHP with questionnaire by means of validation of the judgments with analysis of variance beyond proper the normal mechanisms of analysis of consistency to the method. The main results of the analysis help to show that in this in case that the profile of models of criteria and judgments of the actors is similar, with the final evidence of that it has a dominance of the maintenance of the energy of the deliverer. The main criterion to influence this decision was the risk
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In this thesis, it is developed the robustness and stability analysis of a variable structure model reference adaptive controller considering the presence of disturbances and unmodeled dynamics. The controller is applied to uncertain, monovariable, linear time-invariant plants with relative degree one, and its development is based on the indirect adaptive control. In the direct approach, well known in the literature, the switching laws are designed for the controller parameters. In the indirect one, they are designed for the plant parameters and, thus, the selection of the relays upper bounds becomes more intuitive, whereas they are related to physical parameters, which present uncertainties that can be known easier, such as resistances, capacitances, inertia moments and friction coefficients. Two versions for the controller algorithm with the stability analysis are presented. The global asymptotic stability with respect to a compact set is guaranteed for both cases. Simulation results under adverse operation conditions in order to verify the theoretical results and to show the performance and robustness of the proposed controller are showed. Moreover, for practical purposes, some simplifications on the original algorithm are developed
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In order to guarantee database consistency, a database system should synchronize operations of concurrent transactions. The database component responsible for such synchronization is the scheduler. A scheduler synchronizes operations belonging to different transactions by means of concurrency control protocols. Concurrency control protocols may present different behaviors: in general, a scheduler behavior can be classified as aggressive or conservative. This paper presents the Intelligent Transaction Scheduler (ITS), which has the ability to synchronize the execution of concurrent transactions in an adaptive manner. This scheduler adapts its behavior (aggressive or conservative), according to the characteristics of the computing environment in which it is inserted, using an expert system based on fuzzy logic. The ITS can implement different correctness criteria, such as conventional (syntactic) serializability and semantic serializability. In order to evaluate the performance of the ITS in relation to others schedulers with exclusively aggressive or conservative behavior, it was applied in a dynamic environment, such as a Mobile Database Community (MDBC). An MDBC simulator was developed and many sets of tests were run. The experimentation results, presented herein, prove the efficiency of the ITS in synchronizing transactions in a dynamic environment