245 resultados para Portabilidade numérica

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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One of needs of modern agriculture is the prediction of spatial variability of soil properties at more detailed scales for sustainable management and optimization of management practices. The mathematical model associated with knowledge of variability of soil attributes and mapping of relief forms has helped in agricultural planning. In this regard the aim of this study was to characterize the spatial variability of physical and chemical properties of Oxisols and Ultisols using numerical classification and the digital elevation model. Two distinct landforms: convex for the Oxisol (158 ha) and linear for the Ultisol (172 ha). 53 samples from the Oxisol and 57 samples from the Ultisol were taken. Multivariate analysis of clusters of attributes studied from their euclidean distances was performed. This analysis by dendograms along with digital elevation models for different soils characterized was more homogeneous in Ultisol groups, and less homogeneous for the Oxisol in convex landform. These quantitative methods showed that the landforms conditioned the spatial pattern of soil attributes.

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A Center for Weather Forecast and Climatic Studies of National Institute for Space Research (CPTEC/INPE) has provided to the Brazilian Geodetic community, since 2004, an alternative to correct the GNSS observables from the tropospheric refraction. Numerical Weather Prediction (NWP) Model is used to generate Zenital Tropospheric Delay (ZTD). For the version 1, it was developed a model with horizontal resolution of 100 km, which was updated with Eta model, with resolution of 20 km. This paper provides the most significative details of the current version, as well an evaluation of its quality, using for such ZTD estimates from GPS data collect at RBMC. Comparing to the old version, considerable improvement could be observed from the new model, mainly in Brasilia and Curitiba, reaching up to 55% improvement. When all stations were used in the quality control, almost null bias and RMS of about 4 to 5 cm could be observed.

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Este trabalho abordou o resfriamento rápido com ar forçado de morango via simulação numérica. Para tanto, foi empregado o modelo matemático que descreve o processo de transferência de calor, com base na lei de Fourier, escrito em coordenadas esféricas e simplificado para descrever o processo unidimensional. A resolução da equação expressa pelo modelo matemático deu-se por meio da implementação de um algoritmo, fundamentado no esquema explícito do método numérico das diferenças finitas, executado no ambiente de computação científica MATLAB 6.1. A validação do modelo matemático foi realizada a partir da comparação de dados teóricos com dados obtidos num experimento, no qual morangos foram resfriados com ar forçado. Os resultados mostraram que esse tipo de investigação para a determinação do coeficiente de transferência de calor por convecção é promissora como ferramenta no suporte à decisão do uso ou desenvolvimento de equipamentos na área de resfriamento rápido de frutos esféricos com ar forçado.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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O presente estudo investigou aspectos da representação numérica (processamento numérico e cálculo) e memória operacional de crianças com transtornos de aprendizagem. Participaram 30 crianças de idade entre 9 e 10 anos, ambos os gêneros, divididas em dois grupos: sem dificuldade em aritmética (SDA; N=11) e com dificuldade em aritmética (CDA; N=19), avaliadas pela ZAREKI-R, Matrizes Coloridas de Raven, o Blocos de Corsi e o BCPR. Crianças CDA exibiram escores levemente mais baixos que as SDA quanto ao nível intelectual e nos Blocos de Corsi. Na ZAREKI-R apresentaram prejuízo nos subtestes ditado de números, cálculo mental, problemas aritméticos e total. Crianças CDA apresentaram déficits específicos em memória operacional visuoespacial e comprometimento em processamento numérico e cálculo, compatível com discalculia do desenvolvimento.

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Classical shell-and-tube heat exchangers are usually equipped with segmental baffles. These baffles serve two basic functions: (a) they provide tube supports, thereby preventing or reducing mechanical problems, such as sagging or vibration; (b) they direct the fluid flow over the tubes so as to introduce a cross-flow component, thereby increasing the heat transfer. Segmented baffles have several sources of performance loss, some due to various leakage flows and others caused by stagnation zones. A new concept of longitudinal flow heat exchanger - based on placing twisted tapes along the tube bundle subchannels - was developed to mitigate drawbacks of other types of tubular heat exchangers. In this paper, a numerical model has been implemented in order to simulate the thermal-hydraulic feature of tubular heat exchangers equipped either with segmental baffles or with subchannel twisted tapes. The tube bundle has been described by means of an equivalent porous medium type model, allowing a macroscopic description of the shell-side flow. The basic equations - continuity, momentum and energy - have been solved by using the finite volume method. Typical numerical results have been compared with experimental data, reaching a very good agreement. A comparative analysis of different types of heat exchangers has been carried out, revealing the satisfactory thermal-hydraulic efficiency level of the twisted tapes heat exchangers.

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The aim of this present work was to compare planialtimetric charts obtained from different risings using two different theodolite types, a total station, and a precision level, used as control. Using a total station, an area was marked with clear variations of relief, following a grid, with a distance of 20 meters among stakes. After that, the stakes were read by the total station and two theodolites of different precisions. The geometric leveling was done by a precision level. The data were input in the DataGeosis software and the numerical modelling of the land was made with mesh of maximum rigidity, generating planialtimetric representation for each rising. It was verified, through comparison of the four representations that little variations occur in relation to the control. The closest representation of the control was the planialtimetry based on the data from the total station, in which the representations obtained from the theodolites were identical among themselves. It was concluded that in the process of obtaining detailed planialtimetry of small areas, submitted to the grid, it was not necessary to use composed geometric leveling, reducing work to the exclusive use of a total station or conventional theodolite.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Engenharia Mecânica - FEIS

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)