Computer techniques towards the automatic characterization of graphite particles in metallographic images of industrial materials

The automatic characterization of particles in metallographic images has been paramount, mainly because of the importance of quantifying such microstructures in order to assess the mechanical properties of materials common used in industry. This automated characterization may avoid problems related with fatigue and possible measurement errors. In this paper, computer techniques are used and assessed towards the accomplishment of this crucial industrial goal in an efficient and robust manner. Hence, the use of the most actively pursued machine learning classification techniques. In particularity, Support Vector Machine, Bayesian and Optimum-Path Forest based classifiers, and also the Otsu's method, which is commonly used in computer imaging to binarize automatically simply images and used here to demonstrated the need for more complex methods, are evaluated in the characterization of graphite particles in metallographic images. The statistical based analysis performed confirmed that these computer techniques are efficient solutions to accomplish the aimed characterization. Additionally, the Optimum-Path Forest based classifier demonstrated an overall superior performance, both in terms of accuracy and speed. © 2012 Elsevier Ltd. All rights reserved.

Efeito da escória de siderurgia na nutrição e desenvolvimento inicial de eucalipto

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Efeito do tratamento térmico nas propriedades mecânicas e resistência ao desgaste de um ferro fundido branco multicomponente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da velocidade de deslizamento no desgaste do par tribológico ferro fundido cinzento (MC 12 e MC 13) - ferro fundido cinzento centrifugado

Pós-graduação em Engenharia Mecânica - FEG

O relevo e o sistema de afastamento e tratamento de esgoto da cidade de Marília-SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de variáveis dinâmicas na fundição centrifugada de cilindros de laminação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização de materiais utilizados na fabricação de cilindros de laminação submetidos ao desgaste abrasivo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

O método GPR aplicado à localização de tubulações utilizadas no abastecimento de água na região urbana do município de Belém - Pará

Este trabalho consistiu em avaliar a viabilidade do método GPR (Ground Penetrating Radar) na localização de tubulações de aço, cimento-amianto, PVC e ferro fundido, de diversos diâmetros, utilizadas pela Companhia de Saneamento do Pará (COSANPA), no abastecimento de água à população da região urbana do município de Belém-Pará. Para o alcance deste objetivo foram realizados 14 perfis em 6 locais, distintos da área urbana de Belém, com o intuito de identificar 13 alvos, utilizando-se antenas de 200 MHz e 400 MHz, geralmente usadas neste tipo de levantamento. Os radargramas obtidos com o GPR permitiram identificar quase todos os alvos pesquisados. Apenas 3 dos 13 alvos, não foram plenamente identificados, ficando de fora, apenas os alvos de PVC, de pequena bitola (50 mm e 75 mm). Após o estudo concluímos que o método GPR é muito eficaz neste tipo de aplicação e que sua utilização tem grande valia na localização das redes de abastecimento de água. O que deve facilitar enormemente as obras de expansão da rede, assim como a sua manutenção.

Desenvolvimento de pastilhas cerâmicas à bases de Si3N4 para aplicações tribológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência dos elementos de liga nos parâmetros de processo de fundição de ferros fundidos especiais

Pós-graduação em Engenharia Mecânica - FEG

Estudo e modelagem 3D de um cabeçote para um motor monocilíndrico, 400cc, 4 T

The cylinder head contains the combustion chamber for the air-fuel mixture and the intake and exhaust valves, the valve guide and the valve seat. The cylinder head also is a support for the camshaft and valve rocker. The holes where the spark plugs are connected are designed to fit the better place in the combustion chamber. The cylinder heads often are manufactured using materials such as aluminum and cast iron. The cooling fins located in the outside of the cylinder head are designed for a good heat transfer and therefore their dimensions and positioning are important. This work aims the calculation for a cylinder head to be installed in a 400 cc displacement, gasoline powered, four stroke, single cylinder engine. According to the displacement it will be analyzed the combustion chamber, the intake and exhaust valves, as well as the camshaft and rocker arms. This also a work to help to accomplish the design of a single cylinder engine, where the alternatives parts, cylinder block and crankcase are all already machined and assembled in this campus

Efeito do Estrôncio (Sr) no tratamento de modificação do eutético da liga Al-1%Si

This study aimed to analyze the cooling curves, micro and macrograph alloy Al-1 %Si without the addition of strontium modifier and with the addition of the same. One of the ways of improving mechanical properties of alloy Al -Si is through the modification process. For the experiments two billets of the alloy Al-1%Si cast iron mold in a billet with addition of 0.02% strontium by weight, and the other billet without the addition of modifier were fused. In the solidification process of billet temperature was monitored and recorded every second for later plotting in Origin 8 program and analyzes the cooling curves obtained. The billets were cut and passed by grinding and polishing to perform the macrograph and micrographs. The results concerning the macrograph indicated that billet without the addition of Strontium particle size obtained was more refined than the billet where the strontium modifier was added. Regarding the micrograph, photos stemmed from the optical microscope didn´t show the expected modification effect by the addition of Strontium. This suggests that the low amount of silicon (1 %) present in the alloy used in this study interfered in the change process, because according to the literature review, Strontium 0.022 % by weight is sufficient to fully modify an alloy with 7% Silicon. The results from the cooling curve showed that both the eutectic temperature and the solidification time remained unchanged with the addition of strontium

Avaliação da usinabilidade de cilindros para laminação de tiras a quente

Pós-graduação em Engenharia Mecânica - FEG

Projeto e usinagem do cabeçote para um motor 4 tempos, a gasolina, monocilíndrico de 400 cc e refrigerado a ar

Pós-graduação em Engenharia Mecânica - FEG

Estudo da utilização de ferramentas a base de nitreto de silício (Si3N4) e alumina (Al2O3) na usinagem do ferro fundido vermicular

Machining is one of the most commonly manufacturing processes used in the modern world, consuming millions of dollars annually. Because of this, it is crucial for the automotive industry to reduce costs on their heat-resistant alloy machining processes, such as compacted graphite iron (CGI), which has shown an increasing trend of its application in diesel engine blocks, brakes disks, among other applications, due to its superior mechanical properties to gray cast iron. Despite this advantage, its use is still limited due to its difficulty of machining, moreover, cutting tools are displayed as the main factor in increasing the machining cost. Seeking an alternative to a better machinability of CGI, this paper aims to study two types of ceramic tools developed in Brazil, and benchmark their performance by dry turning. For this, were used CGI class 450 and two tools: ceramic of silicon nitride (Si3N4) and alumina-based (Al2O3), with a cutting speed (Vc) of 300, 400 and 500 m / min; feed (f) of 0.2 mm / rev and depth of cut (ap) of 0.5 mm, using three replicates and starting with new cutting edges. The results showed that the Al2O3 tool had the best performance in Vc of 500 m / min, while the Si3N4 tool had the best results in Vc of 300 m / min. This can be explained by the tool of Si3N4 based include soft intergranular phase, called amorphous, while alumina has higher abrasion resistance due to its high refractoriness. The results make it clear that the tools have significant potential for machining of compacted graphite iron, being necessary a strict control of the cutting parameters used