879 resultados para Linear approximations
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The soybean is the crop most cultivated in Brazil, with great socioeconomic importance. In the agriculture year 2008/09 in Selviria County, Mato Grosso do Sul State, in the Brazilian Savannah, was analyzed the production components and the soybean yield cultivated in a Typic Acrustox on no-tillage. The main purpose objective was select among the production components number of pods per plant, number of grains per pod, number of grains per plant, mass of a thousand grains, mass of grains per plant and population of plants, which of the best linear and spatial correlation aiming explain the soybean yield variability. The irregular geostatistical grid was installed to collect of data, with 120 sampling points, in an area of 8.34 ha. The values of spatial dependence range to be utilized should be among 38.1 and 114.7 meters. The model of the adjusted semivariograma was predominantly the spherical. of the lineal and spatial point of view, the number of pods per plant and the mass of grains per plant they were correlated in a direct way with the soybean yield, demonstrating be the best components to esteem her.
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The rice is one of the main sources of the humanity's feeding. During the agricultural year 2009/2010, in Selviria County, Mato Grosso do Sul State, in the Brazilian Savannah, an experiment was installed with rice upland in a Dystropherric Red Latosol (Typic Acrustox) under no-tillage, irrigated by central pivot, with the purpose of selecting the best components production to explain the variability the irrigated rice yield upland. The geostatistical grid was installed, to collect the data, with 120 sampling points, in an area of 3.0 ha and and homogeneous slope of 0.055 m m(-1). The medium rice yield was of the 5980 kg ha(-1). For the simple lineal regressions, the number of spikelets grenades for panicle presented the best direct potential correlation with the yield rice, given for: PGO = 115,5.NEG(0,770). However, for the multiple lineal regressions, the equation equacao PGO = 2754,30-411,55.NEG-461,07. NEC+436,59. NET it was the one that better she came to esteem the yield rice. However, spatial, it was not possible to establish correlation between the yield rice and the components production, once none of those it presented spatial dependence in their data.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In this work, we use a nonlinear control based on Optimal Linear Control. We used as mathematical model a Duffing equation to model a supporting structure for an unbalanced rotating machine with limited power (non-ideal motor). Numerical simulations are performed for a set control parameter (depending on the voltage of the motor, that is, in the static and dynamic characteristic of the motor) The interaction of the non-ideal excitation with the structure may lead to the occurrence of interesting phenomena during the forward passage through the several resonance states of the system. Chaotic behavior is obtained for values of the parameters. Then, the proposed control strategy is applied in order to regulate the chaotic behavior, in order to obtain a periodic orbit and to decrease its amplitude. Both methodologies were used in complete agreement between them. The purpose of the paper is to give suggestions and recommendations to designers and engineers on how to drive this kind of system through resonance.
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This work identifies and analyzes literature about knowledge organization (KO), expressed in scientific journals communication of information science (IS). It performs an exploratory study on the Base de Dados Referencial de Artigos de Periodicos em Ciência da Informacio (BRAPCI, Reference Database of Journal Articles on Information Science) between the years 2000 and 2010. The descriptors relating to "knowledge organization" are used in order to recover and analyze the corresponding articles and to identify descriptors and concepts which integrate the semantic universe related to KO. Through the analysis of content, based on metrical studies, this article gathers and interprets data relating to documents and authors. Through this, it demonstrates the development of this field and its research fronts according to the observed characteristics, as well as noting the transformation indicative in the production of knowledge. The work describes the influences of the Spanish researchers on Brazilian literature in the fields of knowledge and information organization. As a result, it presents the most cited and productive authors, the theoretical currents which support them, and the most significant relationships of the Spanish-Brazilian authors network. Based on the constant key-words analysis in the cited articles, the co-existence of the French conception current and the incipient Spanish influence in Brazil is observed. Through this, it contributes to the comprehension of the thematic range relating to KO, stimulating both criticism and self-criticism, debate and knowledge creation, based on studies that have been developed and institutionalized in academic contexts in Spain and Brazil.
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The separation methods are reduced applications as a result of the operational costs, the low output and the long time to separate the uids. But, these treatment methods are important because of the need for extraction of unwanted contaminants in the oil production. The water and the concentration of oil in water should be minimal (around 40 to 20 ppm) in order to take it to the sea. Because of the need of primary treatment, the objective of this project is to study and implement algorithms for identification of polynomial NARX (Nonlinear Auto-Regressive with Exogenous Input) models in closed loop, implement a structural identification, and compare strategies using PI control and updated on-line NARX predictive models on a combination of three-phase separator in series with three hydro cyclones batteries. The main goal of this project is to: obtain an optimized process of phase separation that will regulate the system, even in the presence of oil gushes; Show that it is possible to get optimized tunings for controllers analyzing the mesh as a whole, and evaluate and compare the strategies of PI and predictive control applied to the process. To accomplish these goals a simulator was used to represent the three phase separator and hydro cyclones. Algorithms were developed for system identification (NARX) using RLS(Recursive Least Square), along with methods for structure models detection. Predictive Control Algorithms were also implemented with NARX model updated on-line, and optimization algorithms using PSO (Particle Swarm Optimization). This project ends with a comparison of results obtained from the use of PI and predictive controllers (both with optimal state through the algorithm of cloud particles) in the simulated system. Thus, concluding that the performed optimizations make the system less sensitive to external perturbations and when optimized, the two controllers show similar results with the assessment of predictive control somewhat less sensitive to disturbances
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Placa e espaçador de polímero derivado do óleo de mamona (PDOM) (Ricinus communis) foram avaliados clínica, radiográfica e histologicamente na tração linear, fixação e fusão vertebral cervical em 20 cães adultos, sem raça definida, pesando entre 17 e 22kg. Foram sacrificados quatro animais aos 10, 30, 60, 90 e 120 dias de pós-operatório. Após exposição da coluna cervical, por acesso ventral, o disco intervertebral de C4-C5 foi fenestrado e a abordagem ao canal medular foi feita por meio de fenda óssea. Um espaçador de PDOM foi colocado preenchendo o defeito ósseo. Os corpos vertebrais C4-C5 foram fixados com placa do mesmo material, utilizando-se dois parafusos corticais em cada corpo vertebral. Apenas um animal apresentou déficit neurológico no pós-operatório imediato. Radiograficamente as vértebras mostravam-se normais e alinhadas, sem colapso do espaço intervertebral, porém não houve neoformação óssea entre as vértebras. Ao exame mielográfico, não houve compressão da medula espinhal. Os implantes foram efetivos em manter a tração linear e fixação das vértebras cervicais e não ocorreu a fusão vertebral.
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Objective: The purpose of this study was to compare the dental movement that occurs during the processing of maxillary complete dentures with 3 different base thicknesses, using 2 investment methods, and microwave polymerization.Methods: A sample of 42 denture models was randomly divided into 6 groups (n = 7), with base thicknesses of 1.25, 2.50, and 3.75 mm and gypsum or silicone flask investment. Points were demarcated on the distal surface of the second molars and on the back of the gypsum cast at the alveolar ridge level to allow linear and angular measurement using AutoCAD software. The data were subjected to analysis of variance with double factor, Tukey test and Fisher (post hoc).Results: Angular analysis of the varying methods and their interactions generated a statistical difference (P = 0.023) when the magnitudes of molar inclination were compared. Tooth movement was greater for thin-based prostheses, 1.25 mm (-0.234), versus thick 3.75 mm (0.2395), with antagonistic behavior. Prosthesis investment with silicone (0.053) showed greater vertical change compared with the gypsum investment (0.032). There was a difference between the point of analysis, demonstrating that the changes were not symmetric.Conclusions: All groups evaluated showed change in the position of artificial teeth after processing. The complete denture with a thin base (1.25 mm) and silicone investment showed the worst results, whereas intermediate thickness (2.50 mm) was demonstrated to be ideal for the denture base.
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Objectives: This study evaluated the effect of disinfection by immersion in sodium perborate (50 degrees C/10 min) or microwave irradiation (650 W/6 min) on the linear dimensional change (LDC) of four reline resins (Kooliner-K, New Truliner-N, Tokuso Rebase Fast-T, Ufi Gel Hard-U) and one heat-polymerizing denture base resin (Lucitone 550-L). Methods: Specimens (50.0 mm diameter, 0.5 mm thickness) were made using a split mold with reference points, and divided into two controls and four test groups (u = 8). The distances between the points were measured on the mold (baseline readings), and compared to those obtained from the specimens after: polymerization or immersion in water (37 degrees C) for 7 days (controls); 2 or 7 cycles of disinfection by immersion or microwave irradiation. Results: the two-way ANOVA and Tukey's test (alpha = 0.05) showed that microwave disinfection significantly increased the mean LDC of materials L (-1.43%), N (-1.27%) and K (-1.06%). Material N also exhibited a significant increase in LDC after two cycles of chemical disinfection (-0.73%). For U (-0.47%) and T (-0.21%) materials, no significant changes in LDC were found. Conclusions: Microwave disinfection increases the shrinkage of materials L, N, and K. The dimensional stability of resins U and T was not affected by the disinfection methods evaluated. (c) 2006 Wiley Periodicals, Inc.