309 resultados para remoção mecânica


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This work had with objective to characterize and evaluate the performance of the combined system, involving activated charcoal and ionic exchange resins in the removal of substances organic contaminating of the ethyl alcohol from the fermentation of the cassava starch. To testing was used ethyl alcohol PA 96 oGL, conductivity of 0.90 μS/cm at 25 oC, acidity of 60 mg/L and Barbet test of 43 minutes at 15 oC. The contaminated alcohol was composed of ethyl alcohol additive of higher alcohols, organic acids, ester, diol, aldehydes, ketone and ether. Contaminated alcohol was added 2% activated charcoal and after the adsorption isotherm in ionic exchange resins was tested. The adsorption with activated charcoal was performed in a Water Bath at 30 oC for one hour and a half and shaking. Already adsorption ionic exchange columns occurred at room temperature on columns of 93,4 cm in filling height and diameter of 2.29 cm, for flows of 180 mL/min and 90 mL/min. Samples were collected in the tests with charcoal and with each one of the resins and the following analyses were performed: conductivity, acidity and Barbet test. The medium values for conductivity, acidity and Barbet test after the adsorption in charcoal and cation and anion resins were respectively: conductivity was 240; 354 and 465 μS/cm to 25 oC; acidity of 1.081; 1.103 and 1.062 mg/L and the Barbet test was 21; 20 and 9 minutes to 15 oC. It was observed that the addition of 2% of activated charcoal and the permanence in the columns of adsorption was not sufficient to remove the organic substances contaminating of the ethyl alcohol.

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This article is inserted in a study aimed at the identification of the main barriers for the inclusion of visually-impaired students in Physics classes. It focuses on the understanding of the communication context which facilitates or hardens the effective participation of students with visual impairment in Mechanics activities. To do so, the research defines, from empirical - sensory and semantic structures, the language to be applied in the activities, as well as, the moment and the speech pattern in which the languages have been used. As a result, it identifies the rela tion between the uses of the interdependent audio-visual empirical lan guage structure in the non-interactive episodes of authority; the decrease in the use of this structure in interactive episodes; the creation of educa tional segregation environments within the classroom and the frequent use of the interdependent tactile-hearing empirical language structure in such environments.

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

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The iron and manganese ions are present in a high frequency in water source in Brazil. Despite of the frequency in which such problems occur, the way the problem is faced is still traditional, i.e. focusing on oxidative process instead of solid-liquid separation. The treatment can be very simple, in groundwater, or very complex, when metals are present together with organic matter in water. This article presents a review of principal works besides some important aspects about iron and manganese in natural water, occurrence, forms in natural water, organic complexes, oxidation and removal applying solid/liquid separation processes. Further, a new strategy for iron and manganese removal is presented. The information described does not exhaust the matter, so a large bibliography was cited at the end of the article.

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Modelos escritos através dos conceitos da Mecânica do Dano no Contínuo representam atualmente uma alternativa consistente para a simulação numérica do comportamento de estruturas constituídas por materiais quase frágeis, onde a perda de rigidez em função da fissuração crescente é o fator preponderante da resposta não-linear de seus elementos estruturais. No entanto, modelos de dano apresentam forte dependência de parâmetros internos usados para descrever os critérios e evolução das variáveis de dano, que devem ser calibrados adequadamente para uma resposta mecânica coerente da estrutura. Neste contexto, o artigo mostra um estudo sobre a calibração de parâmetros do modelo de dano de Mazars e sua aplicação na análise numérica de vigas e pórticos planos em concreto armado. O Método dos Mínimos Quadrados é adotado para resolver o problema, em conjunto com a técnica de Gauss-Newton. Em virtude da ausência de resultados experimentais para diversas classes de resistência do concreto, como referência para o processo de calibração, são adotados alguns modelos constitutivos teóricos tanto à tração quanto à compressão. Esse processo de calibração de parâmetros é incorporado a um modelo mecânico em elementos finitos para análise de barras em concreto armado, com a consideração conjunta dos mecanismos complementares de resistência ao cisalhamento, como efeito de pino, armadura transversal e engrenamento de agregados. Uma lei constitutiva exponencial para o decaimento da resistência à tração do concreto é proposta com o objetivo de simular o comportamento do tipo tension softening do material. Testes de simulação envolvendo o modelo proposto foram realizados, comparando-se com resultados experimentais e numéricos mostrando a boa precisão e capacidade de obtenção de cargas últimas em estruturas de barras em concreto armado.

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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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The present study had as objectives to verify the effect of rainfastness of different flutriafol formulations, in laboratory conditions, applied on soybean plants with and without the oil adjuvant in the spray solution, as well as to verify the influence of the oil on the droplet spectrum. The experiment considered ten spray solutions related to five treatments containing flutriafol (four formulations of flutriafol and a flutriafol mixture with tebuconazole), all applied with and without mineral oil. Particles size analysis were based on the determination of the droplet spectrum, medium volumetric diameter and the amount of droplets below 100 μm. All the solutions were sprayed with Teejet XR 11001 (fine droplets). Droplet spectrum was determined in a direct way by diffraction of laser (Malvern Mastersizer S®, version 2.15). Confidence interval at 90% degree was used to compare the mean data. The results showed that the addition of mineral oil in the solutions provided tendencies of larger medium volumetric diameter, smaller amount of droplets below than 100 µm and better uniformity of the droplet spectrum. All of the solutions with the addition of mineral oil presented larger adhesion and/or absorption of the fungicide on the plants in comparison with the solutions without oil. The increase of the time between the application and the rain, caused reduction of the fungicide removal, independently of the rain intensity. The increase of the amount of rain didn't change the relative behavior among the solutions; however, this larger amount of rain caused larger fungicide removal along the time. It was observed significant removal of flutriafol by the rain up to 48 hours after the spray application.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)