565 resultados para propriedades físicoquímicas
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Este trabalho teve por objetivo desenvolver hidrogéis do ácido acrílico e correlacionar as propriedades bioadesivas e a liberação in vitro empregando metronidazol. Para tanto, inicialmente foram preparadas dispersões dos polímeros Carbopol 974 ® e Policarbofil ® nas concentrações de 0,5%, 1,0% e 1,5%, que foram submetidas a testes para avaliação das propriedades bioadesivas, mecânicas e reológicas. As amostras com maior concentração de polímeros (Carbopol 974 ® 1,5%, e Policarbofil ® 1,0% e 1,5%,) foram as que apresentaram melhores resultados nos testes de bioadesão, e portanto selecionadas para prosseguimento dos estudos, que envolveu a incorporação de metronidazol (MTZ) na concentração de 0,5% para estudo de liberação in vitro por 12 horas. O experimento foi realizado por meio do sistema automático com célula de difusão vertical de Franz e solução tampão fosfato pH 7,4 como solução receptora. A temperatura utilizada foi 32,5 o C. Os resultados demonstraram que o tipo e a concentração do polímero influenciou diretamente na liberação do fármaco. Os melhores resultados em termos de controle de liberação foram apresentados pelo polímero Policarbofil ® na concentração de 1,5%
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Geophysics studies in areas impacted by petroleum derivatives describe abnormalities of both low and high electrical resistivity (the opposite of electrical conductivity), confirmed as contaminant phase by chemical analysis: this contradiction can be explained by degrading processes that naturally occur and create sub products that can change the environment conductivity. Monitoring the variation of the parameters mentioned serves as a comparative basis to the variation in geoelectrical parameters, which identified the correlation between the same contaminant parameters and the difference between their behavior studied apart, as well as its relations with the biodegradation process. The results are applied to the fuel distribution and storage sectors, leading to the diagnosis and monitoring of possible groundwater contamination scenarios, and the knowledge of the area exposure time to the contaminant, besides the better remediation alternative and impacts control. Among some conclusions, the most significant are the decrease in conductivity over time, so as the increase in Eh value in the gasoline contaminated tank, as well as the decrease in the pH value in the second tank with ethanol, which can be attributed to its degradation. Comparing the variations in both tanks, it is evident that Eh, pH and electrical conductivity do not behave temporally in a similar way, although some correlations between Eh and pH can be related.
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Pós-graduação em Odontologia - FOAR
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Many types of food contain ingredients or bioactive compounds that provide health benefits. The collagen is a fibrous protein found in the connective tissue of the body, and it plays a part in the tissues resistance and elasticity. Due to their functional characteristics, this protein has been added into foods in order to achieve therapeutic effects. This paper aimed at showing how the collagen formation occurs, and the beneficial effects of this compound in the organism as well as its characteristics, properties and applications in food.
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This study presents a literature review which shows the nutritional, medicinal and antioxidant importance of mushrooms. In this research, the main antioxidant compounds of mushrooms, such as phenolic acids, flavonoids and tocopherols, as well as their mechanisms of action were described. The main in vitro methods used for evaluation of the antioxidant activity of these compounds were approached. The influences from the solvent polarity and the kind of extraction in the acquisition of the antioxidant compounds were also discussed. It was possible to conclude that mushrooms are a source of carbohydrates, proteins and minerals, thus presenting nutritional properties. The functional and medicinal properties are attributed to glucans, besides being excellent sources of natural antioxidants. Regarding the extraction process, it was noticed that the solvent polarity used in the extraction process is determinant in the obtainment of antioxidant compounds.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Seeking to meet the requirements: relatively low cost of materials and wide applicability in the automotive industry. The best option was the steel Dual Phase (DP), because that is lighter, have high formability, meet the cost requirements and applicability, steel Dual Phase (DP) came to meet these requirements with its two-phase microstructure, ferrite and martensite microstructure who claim to respect and mechanical properties. In this context, the aim of this study was to correlate the microstructure revealed in metallography to the mechanical properties observed in hardness and tensile tests. The microstructure is revealed by etching in 2% nital and then captured images of the sample were processed in ImageJ software to aid in determining the volume fraction of the phases present. Therefore, the mechanical properties were evaluated with respect to volume fraction of the steel layers and analyzed DP 600 together with the mechanical properties obtained by Rockwell hardness test and tensile test. With the values of the mechanical properties calculated and tested, it was possible to describe the method of metallography, as the attack phase and counts, so that it can use this relationship tested/calculated property as a qualitative analytical tool. The method used for the correlation between the microstructure and mechanical properties confirmed the importance of the phases present in the Dual Phase steel to obtain the desired mechanical properties in the application of the steel
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This graduation work done study of polyamide 6.6/composite carbon fibres, since its processing, characterization of the main properties. Besides the influence of temperature, UV radiation, salt spray and moisture on the mechanical and viscoelastic behavior. To achieve this goal, the first composite was processed from the heat compression molding using known variables of the process and using the empirical method to find the best value for other parameters. The method processing molding was chosen because it common in composites processing in order to evaluate the influence of crystallinity of the properties that influence the mechanical and viscoelastic behavior laminates. From the obtained laminate specimens were evaluated in weathering, such as: in hygrothermal chamber, UV, salt spray and thermal shock. In another step, the effect produced by these constraints were evaluated by optical microscopy, ultrasound, dynamic mechanical analysis and vibration tests. This project was conducted at the Department of Technology and Materials of UNESP in Guaratingueta, where all the equipment and techniques for the implementation of this project met available. After the tests proved the applicability of the composite polyamide 6.6/carbon fibers in aeronautical applications with resistance the main climatic influences
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Pós-graduação em Ciência dos Materiais - FEIS
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Pós-graduação em Ciência Florestal - FCA
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Pós-graduação em Medicina Veterinária - FMVZ
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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This work aims to study the Dual-Phase 600 and 780 steels, which are part of technology development project materials for the automotive industry. It is worth underscoring the antagonistic properties as the Dual-Phase steel assemble, high mechanical strength and elongation due its microstructure, ferrite and martensite. These properties are obtained by a intercritical heat treatment which facilitates the formation of a hardness metastable microstructure shaped plates of low carbon steels. The applicability of Dual Phase steel in the structure of vehicles is huge and its production is already on a commercial scale, so the study and development of this material implies lower cost in automobile manufacturing processes. The dual phase steels DP600 and DP780 underwent tensile, hardness and metallographic analysis to evaluate and comparing its properties. The results indicate that the DP780 steel has higher strength and hardness than the DP600 steel and its microstructure consists of martensite higher fraction which accounts for the higher resistance and hardness. However, the DP600 has higher conformability to DP780 steel