969 resultados para BULK VISCOSITY


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In this work we solved the time dependent Ginzburg-Landau equations to simulate homogeneous superconducting samples with square geometry for several lateral sizes. As a result of such simulations we notice that in the Meissner state, when the vortices do not penetrate the superconductor, the response of small samples are not coincident with that expected for the bulk ones, i.e., 4. πM=. -. H. Thus, we focused our analyzes on the way which the M(. H) curves approximate from the characteristic curve of bulk superconductors. With such study, we built a diagram of the size of the sample as a function of the temperature which indicates a threshold line between macroscopic and bulk behaviors. © 2013 Elsevier B.V.

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In this work, thermoplastic starch (TPS)-clay bionanocomposites were obtained by an innovative methodology using a combination of methodologies commonly used in the composites and nanocomposites preparations. The main objectives or novelties were to confirm efficiency of the processing methodology by field emission gun scanning electron microscopy and investigate the effect of clay content on the spectroscopic, bulk and surface hydrophilic/hydrophobic properties of these bionanocomposites. Raman and FTIR spectroscopies confirmed the changes in the spectroscopic properties of the TPS bionanocomposites with the addition of the clay materials. Water absorption and contact angle measurements were also used to analyze the effect of the clay content on the hydrophilic properties of the TPS bionanocomposites. The results also showed that the addition of the cloisite-Na+ clay increased the bulk and surface hydrophobicities of the TPS matrix, which may increase its industrial application, particularly in manufacturing of food containers. © 2013 Elsevier B.V.

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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The aim of the current review was to investigate the implications of the surface and bulk properties of abutment implants and their degradation in relation to periodontal health. The success of dental implants is no longer a challenge for dentistry. The scientific literature presents several types of implants that are specific for each case. However, in cases of prosthetics components, such as abutments, further research is needed to improve the materials used to avoid bacterial adhesion and enhance contact with epithelial cells. The implanted surfaces of the abutments are composed of chemical elements that may degrade under different temperatures or be damaged by the forces applied onto them. This study showed that the resulting release of such chemical elements could cause inflammation in the periodontal tissue. At the same time, the surface characteristics can be altered, thus favoring biofilm development and further increasing the inflammation. Finally, if not treated, this inflammation can cause the loss of the implant.

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Objectives: To determine the marginal adaptation of bulk-fill composites in class II MO cavities.Methods: Standardized class II MO cavities with bevelled enamel margins were prepared in 40 extracted human molars. The teeth were randomly assigned to one of the five experimental groups (n = 8). The teeth were restored with two horizontal increments of composite (4 mm and 2 mm thickness). The experimental groups were (1st/2nd increment): Gr. A - Venus Bulk-Fill/Venus Diamond; Gr. B - Tetric EvoCeram BulkFill/Tetric EvoCeram; Gr. C - Surefil SDR/Ceram-X; Gr. D - SonicFill; Gr. E - Ceram-X/Ceram-X (control). After finishing procedures, impressions were made using a polyvinyl siloxane and epoxy resin replicas were obtained. Thermo-mechanical stressing was carried out 24 h after the restorative procedure. All specimens were submitted to 240,000 occlusal loading and simultaneous 600 thermal cycles in water at 5 degrees C and 50 degrees C. After loading, a new set of epoxy resin replicas was obtained. Scanning electron microscopy was carried out at 200x magnification. Results for the marginal adaptation were expressed as percentages of continuity relative to the exposed interface and analyzed by ANOVA and Duncan post hoc test (p < 0.05).Results: In enamel, no significant differences were detected before and after thermo-mechanical loading between groups. In dentine, the worst results were observed in Gr. A.Conclusion: By applying simple layering techniques, bulk-fill materials do not allow better marginal adaptation than a standard composite. Clinical significance: A new class of resin-base composite (bulk-fill) was recently launched on the market. The bulk-fill composites exhibited adequate marginal adaptation and similar to the results of the standard composite. (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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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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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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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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BACKGROUND Density and viscosity are properties that exert great influence on the body of wines. The present work aimed to evaluate the influence of the alcoholic content, dry extract, and reducing sugar content on density and viscosity of commercial dry red wines at different temperatures. The rheological assays were carried out on a controlled stress rheometer, using concentric cylinder geometry at seven temperatures (2, 8, 14, 16, 18, 20 and 26 degrees C).RESULTSWine viscosity decreased with increasing temperature and density was directly related to the wine alcohol content, whereas viscosity was closely linked to the dry extract. Reducing sugars did not influence viscosity or density. Wines produced from Italian grapes were presented as full-bodied with higher values for density and viscosity, which was linked to the higher alcohol content and dry extract, respectively.CONCLUSIONThe results highlighted the major effects of certain physicochemical properties on the physical properties of wines, which in turn is important for guiding sensory assessments. (c) 2014 Society of Chemical Industry