1000 resultados para Ondas de tensão
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The industry generally has sought materials with high mechanical resistance, low density, thermal stability and corrosion resistance. In the aerospace industry, for example, the use of aluminum alloys, such as Al 2024-T351 and Al 7075-T7351, have become essential. However, the use of these materials often do not resulted in a satisfactory performance of the component, since the presence of cracks can cause total rupture of the component, even with a tension below the yield stress of the material, unexpectedly. In this work, these aluminum alloys were analyzed and samples were modeled by the finite element method. Moreover, in the models were applied two different types of cracks, central and edge crack, a vertical force was applied to result in a tension 70% of the yield stress of the material analyzed. Through stress asymptotic distribution in the region near the crack tip were calculated the values of the stress intensity factors for each crack length, after the stress intensity factors characterized were compared graphically with the values of fracture toughness found in the available literature
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Ciência Animal - FMVA
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Pós-graduação em Engenharia Elétrica - FEIS
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The magazines destined to the adolescent public are many times searched as a resource of information about sexuality, body, relationships and adolescence. The Capricho magazine is a biweekly feminine magazine directed to teenagers. In this qualitative-descriptive study it was made the content analysis of the section about sex of 18 editions published in 2010 with the aim of identifying and discussing the predominant representations of sexuality. It was identified the predominance of negative representations, like relations between sexuality and fear, tension, shame and beauty imperatives. It can be detached that the feminine sexuality is not approached through its pleasant, positive and health aspects, but through negative representations that, instead of being discussed, are naturalized, put as normal and expected by the magazine’s discourse.
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The application of ultrasonic waves during the initial setting of the glass ionomer cements (GIC) has demonstrated increase of the cure speed, reduction of air bubbles and improves in some mechanical properties. The aim of this study was to evaluate the effect of the ultrasound on the microhardness and the superficial roughness in two GICs (FUJI IX GP (GC Corporation) and Ketac Molar EasyMix (3M ESPE)). Forty specimens were confectioned, twenty for evaluation of the superficial roughness and twenty for evaluation of the microhardness. Half of them received for thirty seconds the ultrasonic waves application. The readings of the roughness had been carried before and after the toothbrushing test. The twenty remaining specimens had been polished with abrasive sandpapers of decreasing granulations and submitted to the hardness test. The results, analyzed for the variance analysis (ANOVA) (p<0,05), had demonstrated increase of the hardness for all the groups with the application of ultrasonic waves, being bigger for the Ketac Molar EasyMix. The ultrasound application also caused significant reduction of the superficial roughness for the Ketac Molar EasyMix. After the toothbrushing test, this last property increased for all the materials. It could be concluded that the application of ultrasonic waves was effective in increasing the superficial hardness of the materials and that it improved the roughness of the Ketac Molar EasyMix before the toothbrushing test.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em História - FCHS
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em História - FCLAS
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Pós-graduação em Engenharia Elétrica - FEIS
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Pós-graduação em Engenharia Mecânica - FEIS
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Pós-graduação em Ciência dos Materiais - FEIS
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Pós-graduação em Odontologia Restauradora - ICT