795 resultados para Sistemas de potência multi-áreas


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This study presents the Environmental Sensibility Mapping to oil spillings on the Potengi estuary - RN and neighboring coastline through remote sensing data, collecting, treatment and integration of the geomorphologic, oceanographic (temperature, salinity, density, direction and intensity), meteorological (wind speed and direction) and high resolution seismic (bathymetry and sonography) data. The Potengi river estuary is located on the eastern coastline of the Rio Grande do Norte State, being inserted in the geological context for the coastal Pernambuco-Paraíba basin and spreading over 18 km; it shelters the Natal harbor zone and an oil terminal, centralizing, therefore, important oil transport operations that can cause accidental spillings. Under the oceanographic point of view, the Potengi estuary is characterized by the absence of any expressive thermic stratification, being classified as partially mixed, B type according to Pritchard (1955), and 2 type in conformity to the stratification-circulation diagram by Hansen & Rattray (1966). Two main wind systems are responsable for the formation of wave sets that occur in the area. The dynamic tide presents, in the Natal Harbor, mean amplitude in spring and quadrature tides, with around 2.8 and 2m, respectively. The mechanism of saline tide mixing was defined through the salinity which is the main parameter for the identification of this mechanism. Important variations of the salinity mean values (36.32 psu), temperature (28.11ºC) and density (22.96 kg/m3) in the estuarine waters presented features belonging to low latitude regions. The water temperature follows the air temperature variations, in the region, with expressive daily amplitudes. In this study, the identification of the estuarine bed morphology through bathymetric and sonographic analysis, had the purpose to evaluate the influence of the superficial and bottom currents for the bottom shaping. In this way, the use of the side scan sonar showed, to be very useful in the identification of the bottom morphology and its relationship with the predominant action of the tidal currents in the Potengi estuary. Besides, it showed how the sonograms can be a support to the comparison of the several patterns derived from the local hydrodynamic variations. The holocene sediments, which fill the estuarine channel, are predominantly sandy, varying from selected, sometimes silty. The sedimentation is controlled by the environmental hydrodynamic conditions, being recognized two important textural facies: Muddy Facies and Sandy Facies. The distribution of these textural facies apparently oscillates owing to the tidal cycle and flow intensity. Each one of the above mentioned data was integrated in a Geographic Information System (GIS), from which was produced the Environmental Sensibility Map to oil spillings with Coastal Sensibility Index (CSI) to the Potengi estuary. The integrated analysis of these data is essential to oil spilling contingency plans, in order to reduce the spilling environmental consequences and to make efficient the endeavours of contention and cleaning up/removal on the Natal Harbor. This study has the aim to collaborate for the increase of informations about the estuarine environment and contribute to a better management of the question: environment/polluting loads

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This study includes the results of the analysis of areas susceptible to degradation by remote sensing in semi-arid region, which is a matter of concern and affects the whole population and the catalyst of this process occurs by the deforestation of the savanna and improper practices by the use of soil. The objective of this research is to use biophysical parameters of the MODIS / Terra and images TM/Landsat-5 to determine areas susceptible to degradation in semi-arid Paraiba. The study area is located in the central interior of Paraíba, in the sub-basin of the River Taperoá, with average annual rainfall below 400 mm and average annual temperature of 28 ° C. To draw up the map of vegetation were used TM/Landsat-5 images, specifically, the composition 5R4G3B colored, commonly used for mapping land use. This map was produced by unsupervised classification by maximum likelihood. The legend corresponds to the following targets: savanna vegetation sparse and dense, riparian vegetation and exposed soil. The biophysical parameters used in the MODIS were emissivity, albedo and vegetation index for NDVI (NDVI). The GIS computer programs used were Modis Reprojections Tools and System Information Processing Georeferenced (SPRING), which was set up and worked the bank of information from sensors MODIS and TM and ArcGIS software for making maps more customizable. Initially, we evaluated the behavior of the vegetation emissivity by adapting equation Bastiaanssen on NDVI for spatialize emissivity and observe changes during the year 2006. The albedo was used to view your percentage of increase in the periods December 2003 and 2004. The image sensor of Landsat TM were used for the month of December 2005, according to the availability of images and in periods of low emissivity. For these applications were made in language programs for GIS Algebraic Space (LEGAL), which is a routine programming SPRING, which allows you to perform various types of algebras of spatial data and maps. For the detection of areas susceptible to environmental degradation took into account the behavior of the emissivity of the savanna that showed seasonal coinciding with the rainy season, reaching a maximum emissivity in the months April to July and in the remaining months of a low emissivity . With the images of the albedo of December 2003 and 2004, it was verified the percentage increase, which allowed the generation of two distinct classes: areas with increased variation percentage of 1 to 11.6% and the percentage change in areas with less than 1 % albedo. It was then possible to generate the map of susceptibility to environmental degradation, with the intersection of the class of exposed soil with varying percentage of the albedo, resulting in classes susceptibility to environmental degradation

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Os últimos vinte anos caracterizaram-se pela proliferação de tecnologias que tornaram possível decifrar o genoma das espécies, localizar e identificar particularidades na sua seqüência, elucidar as suas funções dentro dos sistemas biológicos e, sobretudo, começar a entender os mecanismos que controlam as interações entre os genótipos e os estímulos ambientais, que são responsáveis pela diversidade fenotípica. Estes estudos sobre as bases moleculares da variabilidade fenotípica abriram uma nova abordagem científica, caracterizada pela multiplicidade das questões envolvidas, que resultou no surgimento de novas áreas de pesquisa, cujos conhecimentos estão sendo aplicados em diversos campos da biologia, inclusive na zootecnia. Tendo em vista o grande impacto que tais conhecimentos estão tendo sobre a compreensão dos fenômenos biológicos, parece ser oportuno fazer uma avaliação das potencialidades de aplicação das abordagens de Genômica Funcional em pesquisas de nutrição e alimentação de ruminantes. Nesse contexto, este artigo está focado na descrição das principais ferramentas genômicas disponíveis e na discussão sobre a viabilidade de se utilizar as informações por elas geradas em benefício da produção animal.

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A diversidade de espécies de vespas sociais associadas à vegetação de cerrado no Oeste da Bahia foi analisada neste estudo. Dentre as dezenove espécies de vespas sociais encontradas, Chartergus globiventris de Saussure, Chartergellus communis Richards e Metapolybia cingulata (Fabricius) são registradas pela primeira vez para o estado. O cerrado arbóreo, apesar de apresentar maior riqueza (S = 19) e maior diversidade de espécies (H' = 2,33), apresentou níveis de abundância (N = 87 ninhos) inferiores aos sistemas agrícolas (N = 107 ninhos; S = 8 espécies; H' = 1,84). A fisionomia de cerrado campo sujo apresentou a menor abundância de colônias de vespas sociais (N = 61) e valores intermediários de riqueza (S = 13) e diversidade (H' = 2,20).

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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O Pontal do Paranapanema, extremo oeste do Estado de São Paulo, é conhecido em todo o Brasil devido aos conflitos pela posse da terra, protagonizados pelo Movimento dos Trabalhadores Rurais Sem Terra (MST), que transformou significativamente a paisagem da região, onde atualmente se observam pequenas ilhas de assentamentos rurais imersos numa matriz de grandes pastagens. O Código Florestal prevê que esses assentamentos, assim como qualquer propriedade rural, deve manter 20% de sua área com cobertura vegetal arbórea. Essa área, conhecida como Reserva Florestal Legal, deve ser restaurada, caso não exista. Assim, esta pesquisa se desenvolveu no assentamento Santa Zélia, Município de Teodoro Sampaio, São Paulo, numa área de 15 ha de Reserva Legal. Seis famílias desse assentamento foram responsáveis pela restauração da área, através de módulos agroflorestais (Taungya) temporários. Dois indicadores foram utilizados para avaliação econômica da produção agrícola na área: Valor Presente Líquido (VLP) e Relação Benefício-Custo (RB/C). Os resultados indicaram valores positivos em todas as famílias analisadas, levando à conclusão de que sistemas agroflorestais podem ser adotados na recuperação de áreas de reserva legal em propriedades rurais. Sua maior ou menor viabilidade econômica irá depender de um manejo mais intenso na área para produção agrícola e de preços satisfatórios para venda no mercado.

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Man cultivates the soil for centuries, but the intensive business and use of the soils under Cerrado vegetation for agricultural production grew out of the seventies. The objective of this study was to evaluate soil physical characteristics as a function of sampling time and the soil uses in a Cerrado area in Uberlandia City - MG, Brazil. The managements were adopted: degraded pasture (M-1), conventional tillage (M-2), minimum tillage (M-3), tillage absence (M-4), no-tillage (NT) for three years (M-5); NT for nine years (M-6), NT for three years after Pinus (M-7), PD for one year after Pinus (M-8) and Pinus forest (M-9) with 25 years old. The evaluations were conducted in 2002/03 growing season, in two areas. The soils were: area 1, an Oxisol (Red Latosol - LV-1, M-1 through M-5) and area 2, two Oxisols (Red Latosol and Red-Yellow Latosol - LVA and LV-2, M-6 through M-9). The physical attributes studied changed depending of the soil class, sampling time and management systems, with emphasis on the area 2 soils, which, in general, better preserved its main physical attributes. Managements with intense tillage, such as the M-2, are the most soil physically degrade, presenting mostly negative changes to soil bulk density, total porosity, microporosity and macroporosity. Since the systems which promote less tillage, in short term, to preserve desirable physical attributes. The M-9 system had the lowest attributes range, compared to the others.

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This work presents an algorithm for the security control of electric power systems using control actions like generation reallocation, determined by sensitivity analysis (linearized model) and optimization by neural networks. The model is developed taking into account the dynamic network aspects. The preventive control methodology is developed by means of sensitivity analysis of the security margin related with the mechanical power of the system synchronous machines. The reallocation power in each machine is determined using neural networks. The neural network used in this work is of Hopfield type. These networks are dedicated electric circuits which simulate the constraint set and the objective function of an optimization problem. The advantage of using these networks is the higher speed in getting the solutions when compared to conventional optimization algorithms due to the great convergence rate of the process and the facility of the method parallelization. Then, the objectives are: formulate and investigate these networks implementations in determining. The generation reallocation in digital computers. Aiming to illustrate the proposed methodology an application considering a multi-machine system is presented.

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