907 resultados para Link variables method


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This communication reports that FeWO 4 nanocrystals were successfully synthesized by the microwave-hydrothermal method at 443 K for 1 h. The structure and shape of these nanocrystals were characterized by X-ray diffraction, Rietveld refinement, and transmission electron microscopy. The experimental results and first principles calculations were combined to explain the electronic structure and magnetic properties. Experimental data were obtained by magnetization measurements for different applied magnetic fields. Theoretical calculations revealed that magnetic properties of FeWO 4 nanocrystals can be assigned to two magnetic orderings with parallel or antiparallel spins in adjacent chains. These factors are crucial to understanding of competition between ferro- and antiferromagnetic behavior. © 2012 Elsevier Inc.

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This work presents an alternative approach based on neural network method in order to estimate speed of induction motors, using the measurement of primary variables such as voltage and current. Induction motors are very common in many sectors of the industry and assume an important role in the national energy policy. The nowadays methodologies, which are used in diagnosis, condition monitoring and dimensioning of these motors, are based on measure of the speed variable. However, the direct measure of this variable compromises the system control and starting circuit of an electric machinery, reducing its robustness and increasing the implementation costs. Simulation results and experimental data are presented to validate the proposed approach. © 2003-2012 IEEE.

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Procymidone, a potentially carcinogenic and mutagenic pesticide, can contribute to environmental and human contamination when applied to apple crops. In this work, we propose a reliable and sensitive method to determine procymidone in Brazilian apples. The method involves differential pulse (DPV) and square-wave voltammetry (SWV) techniques on a glassy carbon electrode. In a supporting electrolyte solution of 0.5 mol L−1 NaOH, procymidone undergoes an irreversible one-electron oxidation at +1.42 V by cyclic voltammetric vs. Ag|AgCl, KCl 3 M reference electrode. The proposed DPV and SWV methods have a good linear response in the 8.00–20.0 mg L−1 range, with limits of detection (LOD) of 0.678 and 0.228 mg L−1, respectively, in the absence of the matrix. We obtained improved LOD (0.097 mg L−1) in the presence of apple matrix and the supporting electrolyte solution. We used three commercial apple samples to evaluate recovery, and we achieved recovery percentages ranging from 94.6 to 110 % for procymidone determinations. We also tested the proposed voltammetric method for reproducibility, repeatability, and potential interferents, and the results were satisfactory for electroanalytical purposes.

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Uma nova tendência em termos de ações para o desenvolvimento vem se configurando. Trata-se de ações que levam em conta o território e seus atores. Nesse âmbito, insere-se a metodologia de indução do Desenvolvimento Local Integrado e Sustentável (DLIS). Esse Programa de política pública se constitui uma estratégia participativa de indução do desenvolvimento, pela qual se mobilizam recursos das comunidades, que em parceria com o Estado (em seus três níveis) e o mercado, realizam diagnósticos, identificam potencialidades e vocações, elaboram planos integrados de desenvolvimento, na perspectiva de envolvimento dos sujeitos como proponentes e protagonistas da ação social em seus territórios. Com este trabalho, buscou-se compreender a multidimensionalidade do processo de DLIS, no estado de Roraima, procurando, ao mesmo tempo, o estabelecimento de um nexo causal entre as trajetórias sócio-econômicas (resultados) do DLIS e o capital social. A pesquisa se enquadrou na modalidade qualitativa. Adotou-se como estratégia metodológica o estudo de caso, envolvendo os municípios de Rorainópolis, Uiramutã, Baliza e Pacaraima. Três dimensões analítico-contextuais foram adotadas, quais sejam: conceitual, de implementação e de impacto. Na avaliação do capital social, as variáveis participação, confiança, cooperação e redes foram consideradas. Na interpretação dos dados, as seguintes abordagens foram utilizadas: análise contextual, análise descritiva, análise das diferenças de proporções e análise de correspondência. Os resultados da pesquisa revelaram que alguns conceitos e categorias adotados pelo Programa, embora relevantes, apresentam alguma ordem de problema. Dois municípios, Rorainópolis e Uiramutã, foram considerados municípios de bons resultados. Isso porque atenderam a um conjunto de questões que expressavam condições desejáveis para que o desenvolvimento local integrado e sustentável, em suas múltiplas dimensões, se efetivasse. Por seu turno, os municípios de Baliza e Pacaraima foram classificados como municípios de maus resultados. Os resultados do DLIS em Rorainópolis e Uiramutã estão associados ao capital social (relação positiva). A despeito da extensa literatura que trata da relevância desse tema, não se têm, ainda, instrumentos satisfatórios para medir capital social. Nesse contexto, entendese que estes resultados representam, de fato, uma aproximação.

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

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The concept of Functional Urban Regions (FURs), also called Metropolitan Regions (MRs), is not simple. It is clear, though, that they are not simply a combination of adjacent municipalities or areas. Different methods can be used for their definition. However, especially in developing countries, the application of some methods is not possible, due to the unavailability of detailed data. Alternative approaches have been developed based on spatial analysis methods and using variables extracted from available data. The objective of this study is to compare the results of two spatial analysis methods exploring two variables: population density and an indicator of transport infrastructure supply. The first method regards Exploratory Spatial Data Analyses tools, which define uniform regions based on specific variables. The second method used the same variables and the spatial analysis technique available in the computer program SKATER - Spatial 'K'luster Analysis by Tree Edge Removal. Assuming that those classifications of regions with similar characteristics can be used for identifying potential FURS, the results of all analyses were compared with one another and with the 'official' MR. A combined approach was also considered for comparison, but none of the results match the existing MR boundaries, what challenges the official definitions. (C) 2014 Elsevier Ltd. All rights reserved.

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

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Background: We aimed to establish values and parameters using multislice reconstruction in axial computerized tomography (CT) in order to quantify the erosion of the glenoid cavity in cases of shoulder instability. Methods: We studied two groups using CT. Group I had normal subjects and Group II had patients with shoulder instability. We measured values of the vertical segment, the superior horizontal, medial and inferior segments, and also calculated the ratio of the horizontal superior and inferior segments of the glenoid cavity in both normal subjects and those with shoulder instability. These variables were recorded during arthroscopy for cases with shoulder instability. Results: The mean values were 40.87 mm, 17.86 mm, 26.50 mm, 22.86 mm and 0.79 for vertical segment, the superior horizontal, medial and inferior segments, and the ratio between horizontal superior and inferior segments of the glenoid cavity respectively, in normal subjects. For subjects with unstable shoulders the mean values were 37.33 mm, 20.83 mm, 23.07 mm and 0.91 respectively. Arthroscopic measurements yielded an inferior segment value of 24.48 mm with a loss of 2.39 mm (17.57%). The ratio between the superior and inferior segments of the glenoid cavity was 0.79. This value can be used as a normative value for evaluating degree of erosion of the anterior border of the glenoid cavity. However, values found using CT should not be used on a comparative basis with values found during arthroscopy. Conclusions: Computerized tomographic measurements of the glenoid cavity yielded reliable values consistent with those in the literature.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)