Avaliação anatômica e tomografica das estruturas abdominais do Alouatta guariba clamitans (Bugio-Ruivo – Cabrera,1940)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo da resistência à corrosão de ligas Ni-Cr-Mo-Ta E Ni-Cr-Mo-W em solução NaF 0,08 mol/L, pH 4,7 para aplicações odontológicas

A large number of metal alloys are used in Dentistry for the manufacture of fixed and removable dentures. In the oral cavity, these structures are exposed to a chemically aggressive medium, like saliva and mechanical efforts, like mastication. In addition, acidic solutions containing fluoride ions are also frequently used in dental treatments to prevent dental plates and decays development. In this context, it was considered important to investigate the influence that a fourth element could exert when added to the ternary alloy Ni-Cr-Mo, largely used in Brazil. Therefore, electrochemical tests were done to evaluate the resistance to corrosion of quaternary alloy 65Ni-25Cr-5Mo-5Ta and 65Ni-25Cr-5Mo-5W in NaF solution 0,08mol / L, pH = 4.7. For greater understanding the microstructure and morphology of alloys were studied, through metallographic analysis, using optics microscopy and electron microscopy scanning. For the electrochemical tests were applied techniques traditionally used in corrosion researches, such as: potential measures in open circuit (OCP) and cyclic polarization (CP). It was found that both quaternary alloys showed very similar results. Comparing these quaternary alloys with the ternary 65Ni-25Cr-10Mo, it was found that the quaternary alloys exhibit greater resistance to corrosion, in other words, less passivation current density than the ternary alloy, showing that it is advantageous to add a fourth element in the alloy

Utilização de trocadores de calor de placas em espiral em processos da indústria siderúrgica

Stricter environmental policies are shown necessary to ensure an effective pollutant emission control. It is expected for the present year of 2015, that Brazil will assume, at the 21th United Nation's Climate Change Conference (COP21), implementation of commitment to a low carbon economy. This positioning affects the industrial environment, so that is deemed necessary to search for new technologies, less aggressive to the environment, so the adequacies to the new emission policies do not cause a negative effect on production. Almost all of the processes performed in the steel industry demand burning fuel and, therefore, flue gases are sent to the atmosphere. In this present work is discussed the utilization of heat exchangers so, by recovering part of the available heat from the flue gases of certain industrial process, the combustion air is preheated. The combustion air preheat results in less energy requirement, i.e., less need of fuel consumption and, in addition, minor amount of pollutants to be emitted. Due to better fitting to the process, it is studied the utilization of spiral plate heat exchangers. The heat exchanger dimensioning is made by an iterative method implemented in the software Microsoft Excel. Subsequently are analyzed the gains in terms of process's thermal efficiency improvement and the percentage of fuel saving. The latter implies in reduction of the same percentage of greenhouse gases emission