955 resultados para aço avançado de alta resistência


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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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Pós-graduação em Ciências Odontológicas - FOAR

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Pós-graduação em Doenças Tropicais - FMB

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High-density polyethylene (HDPE) water-proof membranes are used as coatings in vinasse (leachate from sugar cane) storage tanks. The leachate is pumped into the tanks at temperatures of 80-90 °C. Due to these high temperatures and acidity of the waste, these membranes can be degraded, cracked and then loose the function for which they have been designed. This may cause contamination of the soil and groundwater. This study evaluated the effect of vinasse in HDPE membranes after 4 months of exposure in a controlled environment. An aggressive, alkaline pH liquid (sodium hydroxide) was also used. The objective was to evaluate the membrane resistance in contact with acidic and alkaline residues. Physical and mechanical tests, measurement of the carbon black content and thermo gravimetric analysis (TGA) were used to determine degradation of polymer membranes after chemical immersion. While sodium hydroxide resulted caused only minor changes in the physical properties, vinasse induced a thickness change of 7.8%. With immersion in vinasse, an average decrease in strength and deformability (yield) of 34% and 23.5% were measured, respectively. The stiffness increased by 7.8% (average) and the tear strength decreased by 2.7% (average).

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Pós-graduação em Ciência e Tecnologia Animal - FEIS

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Nowadays the regular practice of sports is known as a way to obtain a better quality of life. On the other hand, the media has been distorting this idea, determining the ideal body as the hypertrophy phenotype. It is well known that the genetic factor does not allow all individuals to have this body shape. Besides the fact that, the anxiety of these people in obtain quick results, as one of the globalization’s consequence, make use of anabolic steroid to achieve this goal. However the bodybuilding or the strength muscle gain, make anabolic steroids users abuse and in major cases the users do not know the side effects. In front of these considerations, the present study evaluated the effects of the treatment with anabolic steroids and/or high intensity physical training on the corporal developing, the reproductive organs, bone parameters (strength and bone deformation) and seminal parameters as well the social behavior (aggressiveness). In other to obtain the experimental group, male Wistar rats were used, with 75 days old. The groups were divided into: Vehicle Non-Training (NV), Anabolic Steroid-Non-Training (NA), Vehicle-Training (TV) and Anabolic Steroid-Training (TA). These rats received i.m. injections, twice a week, of anabolic steroid (5mg/kg per animal of nandrolona decanoate) or vehicle (the same volume of peanut oil per animal) and the group TV and TA were submitted to physical training three times per week, during eight weeks. The body mass, wet weight of reproductive organs, femur and semen of the different groups were measured. The aggressive test was also realized in two steps: the first, within 4 weeks of the treatment and the other step in the end of the treatment, in this period the animal was isolated. It was not observed alterations in body mass of the groups. Though it was observed a benefic effect on the maximum strength of the... (Complete abstract click electronic access below)

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Therebar of aluminum 1350 AA produced by CBA are used inthe manufacture of wires and cables for electric power transmission, which marketshows increasingly favorableto aluminum due to itslow densityand high electrical conductivity, but to ensure that this materialmeets all specifications of projectsfor electricity transmission, it must have homogeneity in the chemicaland mechanicalproperties.One of the points of improvement in the process of rod production isreducing the high variation of the limitof tensile strengthalong the coils, therefore, this work seeks a better understanding of the factors that significantly influence the mechanical properties of rebar, specifically assessing the influence oftemperatureat the output of the coils, which can cause a recovery effect on the material andif thereare relevantdifferences between the two modes of rebar production: auto and manual.Samples of six coils have been specifically produced forthis study, which weresubsequently subjected to different annealing temperatures for one hour and ten minutes, similar to what occurs in the output of the coil from the machine. The tensile tests showed that aluminum 1350 AA is significantly influenced by temperature, whose behavior was very similar to that presented in the literature. It was found that the phenomenon of recovery occurred more significantly at high temperatures. Through the optical electron microscope Zeiss, 18 surface maps were made with 100x magnification for each sample in different conditions and the images were analyzed using entropy and fractal dimension, aiming to relate the condition of surface hardening on mechanical property of the samples in that condition. The results showed that these methods can be applied, provided they do not have any kind of imperfection on the surface, once they can influence the results. The study concluded that a more efficient cooling is required in ... (Complete abstract click electronic access below)

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

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The success achieved by the use of composite resins in anterior teeth precipitately leads their use in posterior teeth. However, the indiscriminate application of these materials in cavities with several diverse sizes rapidly pointed out their lack of resistance to oclusal and proximal wear. OBJECTIVE: To evaluate the surface roughness of composite resin in relation to finishing and polishing technique. MATERIAL AND METHODS: Eight experimental groups (n = 15) were divided according to finishing and polishing technique: G1 – Z250TM composite resin without surface finishing and polishing; G2 – Z250TM composite resin plus surface finishing and polishing; G3 – P60TM composite resin without surface finishing and polishing; G4 – P60TM composite resin plus surface finishing and polishing; G5 – Prodigy CondensableTM composite resin without surface finishing and polishing; G6 – Prodigy CondensableTM composite resin plus surface finishing and polishing; G7 – SurefillTM composite resin without surface finishing and polishing; G8 – SurefillTM composite resin plus surface finishing and polishing. Three packable and one microhybrid (control group) composite resin was used. The surface roughness was measured using a profilometer at three points in each sample. The results were evaluated by ANOVA and Tukey test (p < 0.05). RESULTS: Prodigy CondensableTM composite resin showed the lowest surface roughness, while SurefillTM showed the highest surface roughness. Comparing the resins used, only between P60TM and SurefillTM there were no statistically significant differences (p > 0,05). CONCLUSION: Surface roughness was lower in all types of resin composites surfaces in contact with Mylar matrix strip than in areas submitted to finishing and polishing procedure.