Utilização da função desirability na otimização do processo de usinagem da superliga NIMONIC 80A

In the current economic scenario, it is important to the incessant search for improvements in production quality and also in reducing costs. The great competition and technological innovation makes customers stay more and more demanding and seek multiple sources of improvement in production. The work aimed to use the general desirability to optimize a process involving multiple answers in machining experiment. The process of cylindrical turning is one of the most common processes of metal cutting machining and involves several factors, in which will be analysed the best combination of the input factors in machining process, with variable response to surface roughness (Ra) and cutting length (Lc) that vary important answers to measure process efficiency and product quality. The method is a case study, since it involves a study of a tool well addressed in the literature. Data analysis was used in the process of doctoral thesis of Ricardo Penteado on the theme using metaheuristicas combined with different methods of bonding for the optimization of a turning process of multiple responses, then used the desirability and analysis tool. Joint optimization by desirability, the method proposed the following combination of input variables, variable cutting speed at 90 m/min ( -1 level), the breakthrough in 0, 12 mm/revol. ( -1 level), the machining depth should be in 1.6 mm (level 1), gum used must be the TP2500 ( -1 level), in abundant fluid (level 1) and laminated material (level 1) to the maximization of the cutting length (Lc) and minimization of roughness (Ra)

Algumas técnicas de construção de alguns poliedros e suas aplicações no ensino

Pós-graduação em Matemática em Rede Nacional - IBILCE

Nanopartículas de Pd suportadas em compósitos óxido-carbono: influência das interações metal-suporte na oxidação de etanol em meio básico

Fuel cells powered directly with ethanol (Direct Ethanol Fuel Cell-DEFC) are very attractive for the possibility of using a renewable fuel in the generation of clean energy. However, it is still necessary to deepen the understanding of catalytic processes and their dependence on the catalytic properties. This work proposes to study the catalytic activity of ethanol oxidation in an alkaline medium of Pd nanoparticles supported in carbon oxide hybrids using various transition metal oxides (MoO3, TiO2, WO3 and ZrO2). The materials prepared were characterized by techniques such as X-ray diffraction, transmission electron microscopy (TEM) and X-ray dispersive spectroscopy (EDX) to verify the structure, the distribution of particles in the supports and the presence of Pd on particles oxide. Experiments of X-rays absorption spectroscopy were carried out using soft X-rays (SXS) to evaluate the changes in the electronic properties of the Pd particles caused by interactions with different oxides. Measurements of cyclic voltammetry and potential sweeps of adsorbed CO oxidation allowed evaluating general aspects of the catalysts' electrochemical behavior and determining the electrochemically active area thereof. The catalytic performances of ethanol oxidation in alkaline medium were evaluated by electrochemical techniques (potential scan and chronoamperometry), and showed an improvement in activity with the addition of oxides in material containing only carbon, which was most pronounced for the catalyst containing TiO2. This improvement was predominantly associated with the electronic effects caused by the interaction of Pd on the support, causing a vacancy in the 4d band of Pd which, in turn, produces variations in adsorption energies of the species...

Dissolução redutiva de minério de ferro por Acidithiobacillus ferrooxidans para a recuperação de metais de interesse econômico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da cinetica bacteriana na biolixiviação de calcopirita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)