1000 resultados para Membranas suporte


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Cu(II), Cd(II), Mn(II) AND Ni(II). Cellulose acetate polymeric membranes had been prepared by a procedure of two steps, combining the method of phase inversion and the technique of hydrolysis-deposition. The first step was the preparation of the membrane, and together was organomodified with tetraethylortosilicate and 3-aminopropyltrietoxysilane. Parameters that exert influence in the complexation of the metallic ion, as pH, time of complexation, metal concentration, had been studied in laboratory using tests of metal removal. The membranes had presented resistance mechanics and reactivity to cations, being able to be an alternative for the removal, daily pay-concentration or in the study of the lability of metals complexed.

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This study aims to structurally evaluate a support of graphite pastille for the lubrication of railway wheels. The proper lubrication of wheel flanges of the railway extends the life of this component, so it is very important that this occurs lubrication to reduce the costs involved in railway maintenance. To prepar the evaluation structural will be used to International Electrotechnical Comission standard (IEC 61373) establishing which load cases should be applied to this component. The applied loads on the support (accordance with IEC) are random accelerations and accelerations due to shocks, thus simulating the conditions that exist along the route of the train. The structural analyzes are performed by the finite element method, with the aid of the Cosmos software. Thus, it is possible to determine the stresses acting on the support, and so the allowable stresses compared with the standard proposed by the AISC. The stress in the structural analyzes are lower than allowable therefore considered for the configuration presented, unexpected structural problems

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Pós-graduação em Química - IQ

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Pós-graduação em Televisão Digital: Informação e Conhecimento - FAAC

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This paper aims to discuss the Internet as a space conducive to the development of in-depth reports. The traditional media, often tied to economic and political issues, do not address issues related to collective and social satisfactorily. The emergence of alternative media is important and necessary for the development of investigative journalism, not tied to particular interests. The collective funding or crowdfunding is a financial alternative for the development of journalistic content and the Agência Pública de Reportagem e Jornalismo Investigativo figures as a medium that uses this feature, among others. The analysis of reports produced by the agent allows you to identify aspects of analytical and investigative construction this vast medium that is the Internet

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência dos Materiais - FEIS

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The objective of this work was to determine the load support capacity (LSC) of an Oxisol and, through compressibility models, relate it to wheel-soil interactions under management systems with one and three sugarcane crop cycles, with mechanized harvest. LSC evaluations were carried out on undisturbed soil samples, collected at planting row and bed, in four layers: 0.00-0.10, 0.10-0.20, 0.20-0.30, and 0.300.40 m. The contact area between wheels and soil was determined in order to estimate the contact pressure by agricultural machinery on the soil. Pre-consolidation pressures were used to determine LSC. The system with three cycles showed higher LSC than the system with only one cycle. The load support capacity of the soil evaluated in the range of friability is greater than the contact pressures applied to the soil by the wheels of the studied agricultural machines.

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In order to estimate the nutritional rehabilitation (NR) during admission of malnourished children with persistent diarrhea (PD) receiving standardized nutritional support (NS), we prospectively evaluated the weight, height, head circumference and arm measurements (AM) of 20 children, 19 below 1 year, admitted to the ward with weigh/age -2.89 to -5.21 standard deviation. Four infants comprised the death group (DG) and 16 survived (SG). The SG was separated, according to initial weight behavior, into weight gain (WG) or weight loss (WL). Compared to SG at admission, DG only had lower AM and more metabolic-infectious alterations (p<05). The survivors presented NR but this was evident for WL only when considering the minimum weight. DG received less calories than SG and weight loss during the pre-death period was higher than for WL (p<05). It was concluded that very altered AM, severe metabolic-infectious insults, low caloric input and high weight loss velocity are associated to bad prognosis; severely malnourished infants with PD began NR during hospitalization while receiving adequate NS, but minimum weight must be considered for this evaluation; AM must be obtained at admission, due to its prognostic value, and adequate NS as well as anthropometric follow-up during the hospital stay are essential.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Introduction: In dentistry, alveolar bone resorption is a limiting factor in the well being of individuals directly interfering in the stomatognathic system, causing problems in the context of overall health. Aiming to promote biological methods that can stimulate bone regeneration, several biomimetic strategies have been developed by the use of diverse materials possible to the bone matrix, culminating in the development of techniques that promote such repair. Objective: This work is a comparative study of the performance of films made with latex as occlusive membrane for Guided Bone Regeneration (GBR) procedure in three preparations: Latex preserved in ammonia, produced by Latex rubber clones IAN873 and PR255 polymerized immediately after collection and without use ammonia as a preservative. Methods: Sixty Wistar rats were randomly divided into 4 groups of 15 animals in which bone defects of critical size (8mm diameter) were made surgically in the skull. Group A was treated by GBR through the membrane latex preserved with ammonia, Group B received the membrane made of latex from IAN873, Group C, the membrane clone PR255 and group D was not treated by GBR. After a period of 7, 15 and 50 days, 5 animals from each group were euthanized, and specimens containing bone defect collected for microscopic examination (descriptive histology and histomorphometry). Results: The results showed that after 50 days there was bone formation in higher proportions in group D (p <0.05, ANOVA followed by Tukey), suggesting that further experiments should be conducted to conclude about the presence of ammonia and the influence of kind of rubber. Conclusion: GOR is a procedure proven effective in the treatment of bone defects. Therefore, further experiments should be conducted to reach a conclusion regarding the presence of ammonia in the latex composition for the manufacture of membranes, as well as the difference induced by the species of rubber.