206 resultados para Spectral method with domain decomposition
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The application of microwave radiation on the sample preparation has been expanding increasingly in areas involving decomposition by wet and dry roads, fusion, extraction, acceleration of chemical reactions, for example. Currently, the use of microwave ovens for analytical purposes are recognized for having excellent performance for organic and inorganic samples. In the international market there are several kinds of microwaves oven which adapt the varied purposes, however yet with elevated prices which incapacitate your use as routine equipment in laboratory. Thus, many researchers have been choosing for developing own projects of microwaves oven production or to use domestic oven for the laboratory, with or without adaptations. For the evaluation of the proposed method was used in the Kjeldahl methodology for determining total nitrogen in samples of crude protein, using a domestic microwave oven and a digester pot made up in TeflonTM and distillation by steam. Were made to adapt and characterization of a domestic microwave oven, the confeccion vessel digester and the metal support for the vessel. The accuracy of the proposed method was confirmed by comparison of two methods, the standard method for conventional heating and by the proposed method, with heating by microwave radiation through the calculated values of relative standard deviation analysis
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MgTiO3 (MTO) thin films were prepared by the polymeric precursor method with posterior spin-coating deposition. The films were deposited on Pt(111)/Ti/SiO2/Si(100) substrates and heat treated at 350 °C for 2 h and then heat treated at 400, 450, 500, 550, 600, 650 and 700 °C for 2 h. The degree of structural order−disorder, optical properties, and morphology of the MTO thin films were investigated by X-ray diffraction (XRD), micro-Raman spectroscopy (MR), ultraviolet− visible (UV−vis) absorption spectroscopy, photoluminescence (PL) measurements, and field-emission gun scanning electron microscopy (FEG-SEM) to investigate the morphology. XRD revealed that an increase in the annealing temperature resulted in a structural organization of MTO thin films. First-principles quantum mechanical calculations based on density functional theory (B3LYP level) were employed to study the electronic structure of ordered and disordered asymmetric models. The electronic properties were analyzed, and the relevance of the present theoretical and experimental results was discussed in the light of PL behavior. The presence of localized electronic levels and a charge gradient in the band gap due to a break in the symmetry are responsible for the PL in disordered MTO lattice.
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A shift of the photoluminescence (PL) emission was observed in ZnS prepared by microwave assisted solvothermal method with the increase of the time in microwave. In this work we reported a study of the optical behavior linking with the structural disorder according to XRD and FEG-TEM results. The reduction of intrinsic defects in the lattice is responsible for the decrease of electronic levels in the band gap changing the PL profile. This effect was confirmed by electronic structure calculations.
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Low crystalline PZT powder samples were successfully synthesized using polymeric precursor method and slow decomposition steps. The polymeric resin precursor was thermal treated in a muffle type oven varying the temperature from 250 °C to 700 °C and the time from 3 to 24 hours in order to investigate the order/disorder mechanism toward the amorphous powders. Powder samples with low crystalline phases were obtained at lower temperatures and long time of thermal treatment, demonstrating a kinetic dependence for organic removal and a thermodynamic barrier for crystallization processes. Through XRD and FTIR spectroscopy characterizations the long time thermal treated samples showed to be composed of the solid solution of metal oxides in absent of organic matter, originating broad XRD peaks profiles and no carbonaceous bands in FTIR spectra. A Photoluminescence characterization showed that the peak emission is higher for disordered and homogeneous phases, which only can be reached through the long time of thermal treatment.
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Pós-graduação em Química - IBILCE
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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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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This paper proposes a technique for solving the multiobjective environmental/economic dispatch problem using the weighted sum and ε-constraint strategies, which transform the problem into a set of single-objective problems. In the first strategy, the objective function is a weighted sum of the environmental and economic objective functions. The second strategy considers one of the objective functions: in this case, the environmental function, as a problem constraint, bounded above by a constant. A specific predictor-corrector primal-dual interior point method which uses the modified log barrier is proposed for solving the set of single-objective problems generated by such strategies. The purpose of the modified barrier approach is to solve the problem with relaxation of its original feasible region, enabling the method to be initialized with unfeasible points. The tests involving the proposed solution technique indicate i) the efficiency of the proposed method with respect to the initialization with unfeasible points, and ii) its ability to find a set of efficient solutions for the multiobjective environmental/economic dispatch problem.
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O presente estudo teve como objetivo analisar o crescimento de machos e fêmeas do ermitão Clibanarius vittatus (Bosc, 1802), da região de São Vicente, São Paulo, Brasil. Foram realizadas coletas mensais de maio/2001 a abril/2003, na Praia dos Pescadores em São Vicente. Os 2.501 animais capturados foram identificados, determinados quanto ao sexo e mensurados quanto ao seu comprimento de escudo cefalotorácico (CEC). Para o estudo sazonal do crescimento, a população foi dividida em classes de tamanho de 5mm de (CEC), e analisada pelo método de Bertalanffy, com o auxílio do software Fisat II. Foram obtidos 703 indivíduos machos e 1.798 fêmeas, com média de tamanho de 8.94±1.80 e 6.61±1.13mm, respectivamente. Constatou-se um padrão de crescimento sazonal, com machos atingindo um tamanho assintótico (14.92mm) superior ao das fêmeas (13.85mm), além de iniciarem o processo de crescimento aproximadamente cinco meses antes destas. Desta forma, é provável que este seja um padrão que auxilia na diminuição da disputa intra-específica por conchas, uma vez que os machos atingiram maior tamanho e estariam disponibilizando conchas menores para as fêmeas.
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Field experiments carried out with Cyperus rotundus L. at low (58-246), medium (318773), and high (675-1198 shoots/m(2)) densities showed sugarcane yield reductions of 13.5, 29.3, and 45.2%, respectively in relation to the control. In the second field experiment, the integration of a mechanic method with two sequences of plowing and disking operations in the dry season, and complementary applications of trifloxysulfuron-sodium + ametrine and sulfentrazone (rainy season) was studied. Average of the chain connected to original shoot showed 92, 95, and 65% of reduction with trifloxysulfuron-sodium + ametrine and surfactant, at the application stages early, preflowering, and full flowering, respectively.
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Dypsis decaryi (Jum.) Beentje & J. Dransf. is an important palm with ornamental commercial value. Although it reproduces sexually, there are no data available as far as what are the factors that affect this species seed germination. The purpose of this work is to study the potential effects of temperature and substrate in Dypsis decaryi seed germination. The research framework is based on randomization, using a 6 X 2 factorial schema (six different temperatures, 25 degrees C, 30 degrees C, 35 degrees C, 20-30 degrees C, 25-35 degrees C and room temperature, combined with two types of substratum, sand and vermiculite) with 5 repetitions of 20 seeds. The researcher made daily records on the number of germinated seeds, and the criteria used was protusion of the germination plug. After 35 days data become stable. The Index of Germination Speed (IVG) and germination percentage were then calculated (data were converted to sen). The averages for these two indexes were compared using the Scott-Knott method with a probability of 5%. The data show that the higher percentages of germination were obtained with a sand substratum at temperatures of 25 degrees C (86%), 25-35 degrees C (92%) and lab room temperature (93%), and with a vermiculite substratum, at temperatures of 25 degrees C (76%), 30 degrees C (83%), 20-30 degrees C (87%), 25-35 degrees C (80%) and room temperature (91%). The seeds germinated sooner in the lab environment, for both substrates. The percentage of germination at 35 degrees C was markedly lower, both on sand (21%) and vermiculite (38%). In this case, the seeds took longer to germinate and germination was not uniform.
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A Clorose Variegada dos Citros (CVC), causada pela bactéria Xylella fastidiosa, é uma séria ameaça à citricultura brasileira, constituindo-se, atualmente, numa das principais doenças dos citros no Brasil. O objetivo desse trabalho foi avaliar cultivares de citros introduzidas quanto à suscetibilidade ou resistência à CVC, em condições de campo. O trabalho foi conduzido em Bebedouro-SP. Os materiais genéticos estudados foram cultivares de tangerinas e híbridos (tangores e tangelos) introduzidas de bancos de germoplasma da Itália, Portugal, Espanha e Córsega. O trabalho foi constituído por 56 parcelas, com três plantas das quais uma foi inoculada, empregando-se o método de encostia, utilizando-se de mudas previamente infectadas como fontes da bactéria. Foram avaliados os sintomas da doença mediante observação visual através de notas e teste de PCR, específico para Xylella fastidiosa. Os materiais genéticos que se apresentaram positivos ao PCR, mas não apresentaram sintomas, e os que foram negativos ao PCR, possuem um potencial de utilização em programas de melhoramento genético visando à resistência e/ou à tolerância à doença.