Avaliação da resistência à corrosão da liga Ti-30Ta submetida a diferentes taxas de deformação visando aplicações biomédicas

This study aims to evaluate the corrosion resistance of Ti-30Ta alloy when subjected to different strain rates. Samples of the alloy Ti-30Ta were obtained from the melting of pure elements in the arc furnace in inert atmosphere (argon gas). Then, the samples were subjected to a thermal treatment and to cold worked to obtain bars. After forging, the samples were machined in accordance with ASTME9-09 standard for carried out compression tests. To microstructural characterization, samples were sectioned longitudinal and transversally and embedded in resin. After, the wet sanding and polishing were performed, followed by a chemical attack, in order to study the microstructure under an optical microscope. Microhardness was measured on the samples that were subjected to microstructural characterization by using microhardness tester. Phases were evaluated by x-rays diffraction. Corrosion tests were carried out to evaluate the influence of deformation on the corrosion resistance. Results show that microstructure was not influenced by deformation

Livros didáticos e concepções de professores: a história da Ciência no ensino de Equilíbrio Químico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resistência de genótipos de palma de óleo (Elaeis guineensis Jacq.) ao ataque de Opsiphanes invirae Hübner, 1808 (lepidoptera: nymphalidae) no Estado do Pará

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Estudo químico dos escapos de Paepalanthus geniculatus Kunth

Eriocaulaceae species are popularly known as sempre-vivas. This family comprising approximately 1.200 species divided into 10 genera, with high endemic levels. Paepalanthus genus has high incidence in the Espinhaço Range region and the report of biological activities. Despite the large number of previous studies with Eriocaulaceae species, Paepalanthus geniculatus has no studies about their scapes, which demonstrates the need for new research to identify their chemical and biological composition. The aim of this work was to study the chemical composition of P. geniculatus ethanolic extract seeking the isolation and identification of metabolites and evaluate the radical scavenging activity of the extract and isolated substances. P. geniculatus were collected in Serra do Cipó-MG in 2013 (Voucher: SANO 3193) and the scapes were dried, crushed and the powder was percolated with ethanol. With the etanolic extract it is carried out a fractionation by gel permeation chromatography, yielding fractions analyzed by TLC assay. The fraction J89 (45,6 mg) was purified by semipreparative HPLC-PDA, resulting in the isolation of substance S1. The fractionation was also performed by medium pressure liquid chromatography, yielding fractions analyzed by TLC assay. The fraction number 4 (92,6 mg) were purified by semipreparative HPLC-PDA resulting in the isolation of substances S2 and S3. The substances S1 and S3 were analyzed by mono and twodimensional NMR, resulting in the identification of 3,4-dihydroxybenzoic acid (protocatechuic acid) and the flavonoid 6-hydroxyquercetin-7-O-β-Dglucopyranoside. The substance S2 were identified by comparison with standards, were it was possible to determine the presence of the flavonoid 6-hydroxy-7- methoxyquercetin-3-O-β-D-glucopyranoside. The evaluation of radical scavenging activity for the extract and the isolated substances using DPPH, showed consistent activity to S1...

Estudo e análise de sistemas de refrigeração industrial integrados a plantas de processo químico

This work approaches the analysis of industrial refrigeration systems applied to a chemical processing industry that, in this case, consists of refrigeration machines, cooling tower system, cold water system and brine system. In this study it is highlighted the function and characteristics of different systems, including the main components, the most important features, their functionality and best practices. The motivation for this work is the fact that refrigeration systems are essential in many industrial processes, presenting a high energy consumption that is related to a significant parcel of production costs. It has aimed to understand the case studied in order to evaluate the energy efficiency of systems and to compare with Carnot efficiency and best available technologies. The assessment aims to identify irregularities, find opportunities and propose solutions that increases the performance of equipment and the overall system efficiency. Therefore, the studies intend to reduce the operation costs and generate gains for the company

Modelagem auto-regressiva na previsão de demanda dos produtos de uma empresa do setor químico

Considering the high competitiveness in the industrial chemical sector, demand forecast is a relevant factor for decision-making. There is a need for tools capable of assisting in the analysis and definition of the forecast. In that sense, the objective is to generate the chemical industry forecast using an advanced forecasting model and thus verify the accuracy of the method. Because it is time series with seasonality, the model of seasonal autoregressive integrated moving average - SARIMA generated reliable forecasts and acceding to the problem analyzed, thus enabling, through validation with real data improvements in the management and decision making of supply chain

Programação por metas e análise envoltória de dados na avaliação de unidades de produção global: uma aplicação em uma empresa do segmento químico

Considering the high competitivity in the market, the application of quantitative methods can assist in analyzing the efficiency of production facilities of areas of export and import processes of the chemical industry sector. In this sense, this work aims to apply the model GPDEA-BCC optimization in order to develop an analysis of the production units of this chemical industry. So, were chosen variables relevant to the process and elaborated a final comparison between the results obtained by the optimization tool and performance indexes provided by the company. These results indicated that some production units should be monitored more carefully because some of them had a low efficiency when analyzed with multi criteria