Programa de Pós-Graduação em Engenharia Mecânica - PPGEM/UNICAMP
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/9629
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Item Acesso aberto (Open Access) Análise da resistência a corrosão do aço carbono revestido com Al55-Zn após deformação mecânica e tratamento térmico(Universidade Estadual de Campinas, 2001-01-12) BESERRA, Antonio Adelmo Freire; FREIRE, Célia Marina de Alvarenga; http://lattes.cnpq.br/6392994144210466Analysis of the corrosion resistance of the 55AI-Zn coating on carbon steel after mechanical deformation and heat treatment The atmospheric corrosion resistance of 55%Al-Zn alloy coating on average is twelve times that of an equal thickness of galvanized coating. However, it has been shown that microcracks were observed at all levels of strain under simple uniaxial tension. Our research has been focused on determining the degree of corrosion experienced by these coatings after deformation under simple tension or bending and how much the heat treatment at '200 DEGREES' or '360 DEGREES' for 16h can influence the corrosion resistance of the coating. The coated sheet samples were strained to 10% or 15% engineering strain while another group of samples was bent to bend angles of '90 DEGREES' or '180 DEGREES'. The corrosion resistance of the samples was evaluated trhough Tafel extrapolation and electrochemical impedance spectroscopy methods. As a result, it was observed that both the straining and the bending of the coating reduces its corrosion resistance. After the heat treatment at '360 DEGREES' the samples strained to 10% or 15% recover their corrosion resistance, but the specimens bended to '90 DEGREES' or '180 DEGREES' recuperate only partially the corrosion resistance after the heat treatments.Item Acesso aberto (Open Access) Estudo analítico experimental de um conjunto gaseificador(Universidade Estadual de Campinas, 1983) MORAES, Sinfrônio Brito; ISMAIL, Kamal Abdel Radi; http://lattes.cnpq.br/2741276950055207The research subject proposed in this study is based on an examination of the parameters significant for the process of ascendent and counter-current gasification. The gasifier which was utilized was a module proto type. The lower module has an extenal diameter of 50 cm and an internail diameter of 42 cm, owing to the refractory and to the double walls designed for the heating of the incoming air. The upper module with an external diameter of 55 cm and an internal diameter of 50,6 cm, is similarly made of double walls in view of the extraction of gas being localized at different The two modules are joined to each other in such a way as to enable a variation in the height of the charging of the gasifier, as well as in the height of the outgoing gas. The process of gasification used in the study was that of air gas or low-BTU gas. The study was divided into two geometries by varying be tween them, the relation of the height of the outgoing gas and the diameter of the gasifier. When gas was extracted by the upper perforation with a relation δ = 3,09 it is denominated upper geometry andwhen δ=214, lower geometry. Five experimento involving different escapes of air were made for each of the geometries. Temperatus were measured at three different points of the gasifier in order to ascertain the behavior of the reaction zones according to the temperatures. The flows of air, gas, gasified coal and steam contained in the air were measured so that the analyses were made in terms of dimensional parameters. The composition of the gas was analyses chromografically in all the experiments undertaken, so as to determine the calorific potential of the gas, the percent of energy in each component of the resultant mixed gas, and the calorific power of the gasifier. In relation to the composition of air gas, the gasification behaved as if it were a mixture of water gas, owing to local ambiental condition. The composition presented, on analysis, parts of hydrogen and methane, thus contributing to an increase in the heating power of the gas and consequently, an increase in the heating potential of the gasifier.