894 resultados para Veiculos espaciais - Entrada na atmosfera


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O material apresenta a estrutura geral de um subsistema de Entrada/Saída, seus princípios do tratamento e complexidade. Destaca assuntos como: Hardware de E/S; Estrutura típica do barramento do PC; Comunicação entre CPU e controladoras; Endereços de algumas portas de I/O do PC; E/S programada – Polling; E/S por Interrupções; e Vetor de eventos do Intel Pentium. O material também trata do Acesso Direto à Memória e a operação de transferência por DMA; os dispositivos de Rede; as operações do subsistema de E/S (Escalonamento, Buferização, Caching, Spooling, Reserva de dispositivo); o tratamento de erros e as operações que podem estar sujeitas a falhas; e por fim, tratamento de requisições de E/S e o ciclo de vida de uma requisição de E/S.

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This dissertation is about the spatial configuration in Natal and processes in the Ponta Negra neighborhood today. Ponta Negra has undergone a number of critical social and spatial changes due to tourism development after the 1990s. It is of special interest to consider the intensification of real estate investment after 2000, when the new airport terminal, located in the neighboring municipality of Parnamirim, was in use. Ponta Negra is the place where most tourists go to, so attracting considerable public investments. New agents of transformation have produced change in the neighborhood as well. The present study aims at analysing the spatial processes in this part of the city. Here, the spatial configuration that resulted from extended real estate investments, both public and private, in recent years, is analysed in detail. The study identifies the multually differentiated, however internally homogenous areas. The concepts of production of space, contemporanean urban development and spatial dynamics are discussed. The research is based on document analysis and field work. Results were plotted to maps and tables. A detailed analysis of the spatial processes in the Ponta Negra neighborhood is undertaken as a conclusion, considering the contemporanean global scenario

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O objetivo deste trabalho foi avaliar cenários de níveis freáticos extremos, em bacia hidrográfica, por meio de métodos de análise espacial de dados geográficos. Avaliou-se a dinâmica espaço‑temporal dos recursos hídricos subterrâneos em área de afloramento do Sistema Aquífero Guarani. As alturas do lençol freático foram estimadas por meio do monitoramento de níveis em 23 piezômetros e da modelagem das séries temporais disponíveis de abril de 2004 a abril de 2011. Para a geração de cenários espaciais, foram utilizadas técnicas geoestatísticas que incorporaram informações auxiliares relativas a padrões geomorfológicos da bacia, por meio de modelo digital de terreno. Esse procedimento melhorou as estimativas, em razão da alta correlação entre altura do lençol e elevação, e agregou sentido físico às predições. Os cenários apresentaram diferenças quanto aos níveis considerados extremos - muito profundos ou muito superficiais - e podem subsidiar o planejamento, o uso eficiente da água e a gestão sustentável dos recursos hídricos na bacia.

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The aim of this work was to evaluate the quality of yellow melon inodorus Valenciano Amarelo (CAC) fresh cut submitted to two cut types and with application postharvest of calcium chloride. After preparation cubes and slices melon were immersed in solution with different calcium chloride (CaCl2) concentrations for two minutes, afterwards they were conditioned in trays of expanded polystyrene (EPS), covered by plastic film of low density polyethylene (PEBD), stored in cold camera to 5 degrees C +/- 1 and analyzed for 8 days. They were evaluated pH, firmness, tritable acidity (AT), soluble solids (SS) sugar reducer and ratio. The pH values varied from 5.27 to 5.68. The sugars reducers content and the ratio were superior in the slices compared to the cubes. The melon slices maintained larger firmness values compared to the cubes and in general there was reduction in the values of this parameter along the storage period for all treatments. Concentrations of 1.0 and 1.5% of CaCl2, result in larger values of firmness. The storage temperature and modified passive atmosphere they contributed to quality maintenance of MP melon. Concentrations of up to 1.0% of CaCl2 they could be recommended to maintain the melon quality MP melon yellow inodorus (CAC).

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The active modified atmosphere effect was evaluated in the quality of squash fresh-cut (MP).. The squash pieces were conditioned in plastic packings and submitted the gases application in the following concentrations: 0.03% CO2 and 21% O-2 (controls T1); 5% CO2 and 4% O-2 (T2); 6% CO2 and 4% O-2 (T3); 7% CO2 and 4% O-2 (T4); 8% CO2 and 4% O-2 (T5). In T6 it was made vacuum application in the packing. The packings containing the squash were stored in to the temperature of 10 degrees C and relative humidity of 75% for 12 days. The evaluated analyses were weigth loss, total acidity (AT), pH, soluble solids (SS), ratio, firmness, color, antioxidant activity for DPPH and carotenoids content. The weigth loss was gradual and low until the ninth day of storage. The values of AT increased along the experimental period being superior for T1 and T2. The increase of SS during the storage of the fresh-cut squash went smaller for T3 and T4. The brightness stayed during the storage being superior for T5, already the color components red and yellow decreased along the experimental period.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico

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The present work, based on the methodological principles of the Comprehensive Discourse Analysis, aimed, through the speech of twelve newly arrived students at the Pedagogy course of the Federal University of Rio Grande do Norte, to understand the moment students start university. It also aimed to analyze the relationship between the schools they were coming from and university entrance as well as the relationship between university and their new students. In the first part of the work, which focused on school knowledge, a comprehensive listening of the speeches of the students led primarily to a distinction, established by the students, between public and private schools, a distinction especially based on the view of superiority of private schools against public ones. The abovementioned interpretation is found in the discussion of the structural duality of Brazilian education which, historically, offers different pedagogical appliances among students of more priviledged social classes and those who come from lower levels of society. The overcome of this duality, aspired by the Brazilian Constitution of 1988, was stopped by the advent of a new economic model neoliberalism, which reinforced the differences between public and private when it prioritized the market on the economic, political and social relations, including educational projects. Impoverishment of public institutions and pauperization of the work of professors affected also the relationship between teachers and studens at the current institution. This is how the teacher becomes the greatest villain at the public management system. All of these references concerning differences in the quality of teaching at public and private schools, expressed by the students interviewed, however, were centered in the preparation for the entrance exam, called vestibular, thus showing a view that the relationship between the student and the school he came from is of a propedeutic kind and even so, reduced to a preparation for an entrance exam. In the second part of the work, which analyzed the relationship between newly arrived students and their university, it was noticed that the latter represents a whole new world. This world is seen as the change at the student´s social statute for now he is grown, takes more responsibilities and is socially respected. This change of attitude established by society and the discovery of a new world which requires more independence from the students, creates in them feelings of pride and fear and they feel insecure when it comes to making decision in the campus because now their decisions deliver a greater load of responsibility. This is when students understand they need to develop autonomy, which is seen, in this work, as the capacity to make conscious decisions. Nevertheless students expressed an understanding of autonomy as something that comes as a gift for those who enter university and not as a process that is constructed from social experiences. For these students, the need to be autonomous refers to the relationships with their teachers and the search for information. This search, however, is also related, according to interviews, to public school financial cuts, which penalize university, and to the lack of employers

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This thesis describes design methodologies for frequency selective surfaces (FSSs) composed of periodic arrays of pre-fractals metallic patches on single-layer dielectrics (FR4, RT/duroid). Shapes presented by Sierpinski island and T fractal geometries are exploited to the simple design of efficient band-stop spatial filters with applications in the range of microwaves. Initial results are discussed in terms of the electromagnetic effect resulting from the variation of parameters such as, fractal iteration number (or fractal level), fractal iteration factor, and periodicity of FSS, depending on the used pre-fractal element (Sierpinski island or T fractal). The transmission properties of these proposed periodic arrays are investigated through simulations performed by Ansoft DesignerTM and Ansoft HFSSTM commercial softwares that run full-wave methods. To validate the employed methodology, FSS prototypes are selected for fabrication and measurement. The obtained results point to interesting features for FSS spatial filters: compactness, with high values of frequency compression factor; as well as stable frequency responses at oblique incidence of plane waves. This thesis also approaches, as it main focus, the application of an alternative electromagnetic (EM) optimization technique for analysis and synthesis of FSSs with fractal motifs. In application examples of this technique, Vicsek and Sierpinski pre-fractal elements are used in the optimal design of FSS structures. Based on computational intelligence tools, the proposed technique overcomes the high computational cost associated to the full-wave parametric analyzes. To this end, fast and accurate multilayer perceptron (MLP) neural network models are developed using different parameters as design input variables. These neural network models aim to calculate the cost function in the iterations of population-based search algorithms. Continuous genetic algorithm (GA), particle swarm optimization (PSO), and bees algorithm (BA) are used for FSSs optimization with specific resonant frequency and bandwidth. The performance of these algorithms is compared in terms of computational cost and numerical convergence. Consistent results can be verified by the excellent agreement obtained between simulations and measurements related to FSS prototypes built with a given fractal iteration

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O objetivo deste trabalho foi avaliar o efeito da irradiação gama associada à atmosfera modificada passiva na qualidade pós-colheita de goiabas 'Pedro Sato', verificando suas características físico-químicas. Foram utilizadas goiabas provenientes da região de Vista Alegre do Alto-SP,Brasil. Após a colheita, as goiabas foram imediatamente transportadas ao Laboratório de Frutas e Hortaliças, pertencente ao Departamento de Gestão e Tecnologia Agroindustrial, da Faculdade de Ciências Agronômicas - UNESP - Câmpus de Botucatu-SP, onde foram armazenadas a 10ºC e 90-95%UR, em câmara frigorífica, por 28 dias. Os tratamentos foram: controle 1 (sem embalagem e sem irradiação); controle 2 (embalagem de poliestireno (PS) + polietileno de baixa densidade (PEBD) e sem irradiação); tratamento 1 (PS+PEBD e 0,2kGy); tratamento 2 (PS+PEBD e 0,6kGy), e tratamento 3 (PS+PEBD e 1,0kGy). As análises realizadas foram: firmeza, sólidos solúveis (SS), acidez titulável (AT) e índice de maturação. Foi utilizado o delineamento inteiramente casualizado, com esquema fatorial 5 x 5 (tratamento x tempo). Concluiu-se que as altas doses de irradiação promoveram efeito negativo nas características físico-químicas da goiaba 'Pedro Sato', e que apenas a menor dose utilizada (0,2kGy) associada à atmosfera modificada conservou frutos com maior qualidade e aceitabilidade, indicado por maiores índice de maturação e teor de sólidos solúveis obtidos.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)