Análise estrutural do suporte de pastilha de grafite para lubrificação de roda ferroviária

This study aims to structurally evaluate a support of graphite pastille for the lubrication of railway wheels. The proper lubrication of wheel flanges of the railway extends the life of this component, so it is very important that this occurs lubrication to reduce the costs involved in railway maintenance. To prepar the evaluation structural will be used to International Electrotechnical Comission standard (IEC 61373) establishing which load cases should be applied to this component. The applied loads on the support (accordance with IEC) are random accelerations and accelerations due to shocks, thus simulating the conditions that exist along the route of the train. The structural analyzes are performed by the finite element method, with the aid of the Cosmos software. Thus, it is possible to determine the stresses acting on the support, and so the allowable stresses compared with the standard proposed by the AISC. The stress in the structural analyzes are lower than allowable therefore considered for the configuration presented, unexpected structural problems

Construção de um equipamento de ensaio de desgaste micro abrasivo por esfera rotativa fixa para análise do desgaste em revestimento duro aplicado por soldagem

Pós-graduação em Engenharia Mecânica - FEIS

Desenvolvimento de revestimentos siloxano-PMMA reforçados por nanotubos de carbono, óxido de grafite e óxido de grafite reduzido para aplicações anticorrosivas

Pós-graduação em Química - IQ

Determinação de fósforo em biodiesel utilizando eletrodo quimicamente modificado com nanopartículas de ferro

Once petroleum is na exhaustible source of energy, alternative fuels are having more prominence. A much discussed option for replacing fossil fuels is the use of biofuels derived from oils or fats, especially biodiesel. The biodiesel preparation is through a reaction named transesterification, a reaction of triglycerides with a short chain alcohol with a catalyst, producing a mixture of fatty acid esters and glycerol. According to ANP (National Petroleum Agency) specifications, biodiesel can have contaminants due to the catalyst or oil used on its synthesis, such as phosphorus, wich can damage the catalytic converter and cause significant increase in the particles emission. This project aims to develop na alternative method using chemically modified electrodes with iron nanoparticles for determination of phosphorus in biodiesel. For the formation of the iron nanoparticles film on the surface of a glassy carbon electrode, was used a iron sulfate solution. The film was formed after 10 successive cycles, with a scanning speed of 50 mV s-1 and a potential range of -0,9 to -1,25 V. To reduce possible oxides on the surface and activate the electrode, it has been subjected to a cathodic polarization with a potential of -1,25 V for 15 minutes in a sodium hydroxide solution. In cyclic voltammograms obtained in the study of the speed of scanning, there is an increase in the intensity of the anodic and cathodic current peaks. The cathodic peak current varied linearly with the square root of scan rate, showing that the electrode is controlled by diffusion. After successive additions of phosphate there is a linear variation in the current peak in the concentration range of 1,0 x 10-7 a 1,0 x 10-6 mol L-1. To determine if the concentration of phosphorus in real sample, the method of adding standard was used by adding aliquots of phosphate ions in the solution containing soy biodiesel extracted with ....

Avaliação do método da quebra do grafite para estimação da sensibilidade de transdutores piezelétricos utilizados na técnica da Impedância Eletromecânica

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influência do veículo na remoção da pasta tri antibiótica do canal radicular

Pós-graduação em Ciência Odontólogica - FOA

Desenvolvimento de detector eletroquímico para cromatografia líquida de alta eficiência baseado em um eletrodo modificado com nanopartículas metálicas para determinação de ácidos carboxílicos em vinhaça de cana-de-açúcar

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Propriedades de pasta e concentração de amido resistente em duas variedades de féculas de raízes de mandioca em diferentes estágios de desenvolvimento

The objective of this work was to analyze the profiles of the concentrations of resistant starch and respective properties of paste of two cassava varieties with different development stages. For the evaluation of the profile of the concentration of resistant starch and paste properties, the starches of the cassava varieties were used IAC 576/70 and Fécula Branca, which were collected with different times of cultivation (10, 11, 12, 13, 14 and 15 months), and the use of these times were according the crop of cassava variety IAC 576/70. For the analysis of paste property the apparel was used RVA and for analysis of resistant starch the enzymatic method was used. The results showed for the paste properties happened significant differences among the two varieties of cassava starch, and in some months they there wasn't differences, and as the results of resistant starch happened differences among the starches the months of July and August, and as for the different development stages only the starch of Fécula Branca that happened significant differences.

Composição química e propriedades de pasta de farinhas de mandioca

This work aimed to analyze the chemical composition and paste properties of cassava flours, from several producers and classifications, marked in different Brazilian cities. Flours were characterized to moisture, ash, fibers, protein, lipids, total sugars and starch. The paste properties were analyzed in RVA. The results showed significant differences to chemical components in cassava flours. The moisture ranged from 4.39 to 10.26, starch (82.19 to 88.90%), ash (0.48 to 1.07%), fiber (3.23 to 6.41%), protein (1.15 to 2.13%), total sugar (0.05 to 0.56%) and lipids (0.40 to 1.24). These differences can be due the variations of raw material and process. The paste properties of flours were different, with viscosity peak ranged from 73.33 to 387.08 RVU, breakdown (2.42 to 248.83RVU, final viscosity (154.92 to 275.5 RVU) and retrogradation tendency (50.75 to 132.5 RVU), showing the influence of kind of processing on flour viscosity.

Propriedades de pasta e térmicas de misturas instantâneas de farinha de soja, fécula e farelo de mandioca

The application of extrusion technology in the food industry has enabled the development of new commercial products of fast preparation, and maintaining the nutritional characteristics after the process. During this process there are changes in raw material due to the action of temperature, humidity and mechanical friction resulting in a modified product which can be used in various industrial applications. This work aimed to evaluate the effect of the composition of the raw material and operating conditions of the extrusion process on the properties of paste and thermal properties in the development of a functional instant flour of cassava and soybean. The results showed significant effects of all operating parameters on the rheological properties studied. The extruded flours showed no residual gelatinization enthalpy, suggesting that the starch in the samples was gelatinized. The experimental conditions of the smallest percentages of cassava residue (10%) and high soybean flour (25%) mixed with cassava starch, extrusion temperature of 75ºC and low screw speed (170rpm) leads to obtain instant flour with desirable characteristics.

Determination of Tetracycline in Environmental Water Samples at a Graphite-Polyurethane Composite Electrode

A bare graphite-polyurethane composite was evaluated in the tetracycline (TC) determination in natural water samples. Using differential pulse voltammetry (DPV), a linear response was observed in the range of 4.00-40.0 mu mol L-1 with limit of detection of 2.80 mu mol L-1, without the need of surface renewing between successive runs. During the tetracycline determination in water samples, recoveries between 92.6 and 100% were found. The results for TC determination in water samples after a pre-concentration stage agreed with spiked value at a 95% confidence level according to student t-test.

Fresh Pasta Production Enriched with Spirulina platensis Biomass

The aim of this work was to study the enrichment of Spirulina platensis in wheat flour to prepare fresh pasta to evaluate the green color and nutritional enrichment in addition to functional properties due to the presence of the bioactive compounds in the cyanobacterium. The pastas were evaluated for the centesimal composition, microbiological contamination, sensorial acceptance and technological characteristics such as cooking time, water absorption, volume displacement and loss of solids. The superior protein contents and the satisfactory technological and sensorial attributes compared with the control with no cyanobacterium showed the usefulness of incorporating S. platensis biomass in the fresh pastas. The microbiological quality was in compliance with the legislation in force. The sensorial quality was considered satisfactory ("liked very much") and purchase intention high ("probably would buy").

Avaliação clínica e radiográfica do extravasamento da pasta de hidróxido de cálcio em dentes com lesões periapicais

It has been evaluated clinically and radiographically the effect of the extrusion of calcium hydroxide paste in teeth with periapical lesions. Twenty-five patients with teeth showing pulp necrosis and periapical lesions were submitted to endodontic treatment. Dressing calcium hydroxide paste, iodoform and propylene glycol were used. Clinically, the symptoms were evaluated after treatment and, radiographically, the reabsorption of extravasated paste and repair process of the periapical lesion. Only three patients had symptoms severe in the first 24 hours, the paste was completely reabsorbed within 15 days and no interference in the repair process.

Oxidação eletroquímica do herbicida tebutiuron utilizando eletrodo do tipo DSA

Tebuthiuron (TBH) is a herbicide widely used in different cultures and known for its toxic effects. Electrochemical methods are promising for removing pollutants such as pesticides. This study showed the degradation of TBH using a DSA® anode operated at current densities of 50 to 200 mA cm-2. Removal presented pseudo-first order kinetics while high-pressure liquid chromatography (UV detection) showed two peaks, ascribed to degradation intermediates. The maximum percentage of total organic carbon removed was 12.9%. Ion chromatography revealed that higher concentrations of nitrate and nitrite ions formed with increasing current density.