Síntese, caracterização e estudos de precursores e de óxidos de molibdênio e de tungstênio

Pós-graduação em Química - IQ

Vidros óxidos contendo átomos pesados para aplicações em óptica não linear e fotônica na região do infravermelho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Hidroxicarbonato de gadolínio ativado com európio ou térbio trivalentes como precursor de óxidos, oxissulfetos e silicatos luminescentes

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

Modelagem computacional de óxidos da família das perovskitas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Aparato assistido por microondas para síntese hidrotérmica de óxidos nanoestruturados

A presente invenção refere-se a um aparato hidrotermal, assistido por microondas, para a síntese de áxidos metálicos nanoestruturados. O dito aparato é constituído por, no mínimo, um recipiente (1) para a reação, transparente às microondas e hermeticamente fechado por uma tampa metálica (3). O recipiente é inserido na cavidade de um forno elétrico de microondas doméstico (11) através de uma furação na parte superior de sua carcaça. O controle da temperatura da reação é feito por um conjunto de termopar (6), multiplicador de tensão (13) e controlador de temperatura (14), os quais determinam a quantidade de radiação emitida pela magnetron (12) do microondas.

Compósitos ppticamente transparentes baseados em celulose bacteriana e boehmita, siloxano e/ou sistema boehmita-siloxano

The present invention comprises composites with multifunctional characteristics, being capable of substituting glass, with significant advantages, with particular emphasis on flexibility, for a variety of applications such as, for example, display screens and others. Among other aspects, the product that constitutes the object of the invention is particularly characterized by rendering bacterial cellulose transparent, in addition to being flexible, biocompatible and able to replace glass in 100% of possible applications. Among other aspects, the development of the composites according to the present invention allows an effective increase in optical transmission, enabling an optical transmission of more than 90%, such transparency being necessary, equally, for the development of medical devices, for example.

Stephen Gray e a descoberta dos condutores e isolantes: tradução comentada de seus artigos sobre eletricidade e reprodução de seus principais experimentos

O livro expõe a trajetória de Stephen Gray (1666‑1736), cientista inglês que dedicou sua vida à Astronomia e à Física, especificamente na área da Eletricidade, e realizou uma série de experimentos que levaram a conclusões inéditas para a época. Sua principal descoberta foi perceber que existem dois tipos de substâncias com propriedades elétricas muito distintas, hoje conhecidas como condutores e isolantes. A obra mostra que Gray foi o primeiro cientista da história a atribuir aos metais e outros condutores a propriedade de atrair corpos leves colocados em suas proximidades, fenômeno que atualmente é conhecido como indução ou polarização elétrica. E também o pioneiro na criação de eletretos, substâncias que apresentam uma eletrização de longa duração, mostrando ainda como preservar temporalmente a eletrização dos corpos. Os autores apresentam uma breve biografia do cientista Stephen Gray, que apesar de sua importância permanece bastante desconhecido dos pesquisadores contemporâneos, principalmente brasileiros, uma vez que seus escritos e experimentos carecem de divulgação no país. Por conta dessa condição, a obra traz a tradução de seus dez artigos sobre eletricidade. Os experimentos de Gray são contextualizados, ilustrados com figuras didáticas e explicados com base nos conhecimentos atuais da Física. O livro mostra também como reproduzir os principais experimentos do cientista inglês com a utilização de materiais de baixo custo. De acordo com os autores, com o objetivo de motivar outros cientistas a se aprofundarem nessas pesquisas e a desenvolverem a obra de Gray de forma que seja utilizada no ensino, o livro busca “resgatar a memória desse grande pesquisador, que tinha um olhar afiado, era bastante preciso em suas explicações, criativo em suas ideias e muito claro em seus textos”

Comportamento dos óxidos de ferro da fração argila e do fósforo adsorvido, em diferentes sistemas de colheita de cana-de-açúcar

In agriculture, the search for higher crop yields based on sustainable soil management has led to a gradual pursuit of knowledge of the variables related to production systems. The identification of the causes of variability of these properties has become a part of strategic planning in the sugar and ethanol industry. This study investigated the spatial variability of iron oxides in the clay fraction and its relationship to soil physical and chemical properties in different sugarcane cultivation systems in the region of Ribeirão Preto, São Paulo State. Two 1-ha plots were outlined in areas with mechanical and manual harvesting systems. Soil samples were taken at 126 points from the 0.00-0.25 m layer in both areas. The mineralogical and chemical data were subjected to geostatistical analyses, to determine the spatial dependence, semivariograms and kriging maps of the properties. To analyze the correlation between the parameters cross-semivariograms were constructed. The spatial variability of chemical properties was greater in areas with mechanical harvesting than burnt harvesting (manual harvesting), whereas the range of the mineralogical properties was largest in the area of green-harvested sugarcane. The properties organic matter, mean crystal diameter goethite had a negatively spatial correlation, while clay was positive correlated with P sorption in the two sugarcane harvest systems.

Modificação da superfície de óxidos de ferro por dextrana derivatizada para aplicações em liberação de fármaco

Pós-graduação em Química - IQ

Estudo da aplicabilidade do sistema pultrudado de fenólica/fibras de carbono em cabos condutores

Pós-graduação em Engenharia Mecânica - FEG

Verificação da eficiência da metodologia Seis Sigma na redução da divergência de estoque em uma indústria de condutores de fluídos

This work was developed in order to reduce the discrepancy found between the stock data of an item in the system and the amount found physically in stock in the company presented on this study case. Therefore, this paper makes a study on system of information that can assist in the collection, control and manipulation of data regarding the company's stock. It is very important to do the inventory management, so we can control the level of this sub-product to meet sales orders and production. In the study discussed below, we used the Six Sigma methodology to identify points that had flaws in the process and thus improve their work where the results show grater process control and provide a reliable database to the point where no further problems of lack of components in stock

Análise da eficiência do cobre, alumínio e PVC como condutores hidráulicos em aquecedores solares

One of society concerns are preserving the environment and the growing energy demand. These two issues are in conflict since most of the energy used today in some way harms the environment. Then is essential to develop and implement ways to clean and renewable energy. In this way, solar energy stands out as a source of clean energy, renewable, abundant and acessible. Solar energy can be harnessed by photovoltaic cells or by solar collectors. The aim of this article is analysethe yield of the solar heather assembled with hydraulic conductive and plastic bottles using three different materials for hydraulic conductors, in order to compare these efficiences and analyze material which has the best cost-benefit in this type of application. The materials analyzed in this study were copper, aluminum and PVC. For this analysis were assembled three alike solar heaters using each one of these materials, and were done several series of measurements of the temperature water output to each heat with flow between 10 and 30 liters per hour. With these data we can analyze the yield and the performance of copper, aluminum and PVC in this application. So we can conclude that aluminum has a higher efficiency, followed by PVC, and the copper had the lowest efficiency. This behavior kept for all values of flow rates examined

Avaliação de sistemas de pultrudados com diferentes tipos de matrizes para aplicação em cabos condutores

In the last decades it has been observed a substantial developing of the electrical energy demand in the societies all over the World. In consequence the electrical energy distribution companies are increasing the quantity of electrical energy through the electrical energy conductor cables, which had grown the sag in the towers of energy transmission. Furthermore, the construction of more transmission towers brings a lot of troubles due environmental protection laws. In this way, looking forward to increase the quantity of electrical energy transmitted through electrical cables conductors, reduce the need of constructing new transmission towers and the sag in them, we suggest in this work the replace of the traditional core of the conductors cables commonly used, made of steel, by a core made by a composite material, which one is made by carbon fibers pultruded with polymeric resins as matrix. In a order to evaluate if the resins more commonly used in structural composites can be applied as matrix to make possible to use the composite material as a core, we made carbon fibers systems pultruded with epoxy, phenolic and polyester resins as matrix and a mechanic and physic-chemistry characterization was done on the systems by Tensile and Poisson tests, differential sprobe calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transformed infrared spectroscopy (FTIR), following their correspondents standards

Desenvolvimento de filmes finos de Bi3NbO7 pelo método dos precursores poliméricos em diferentes eletrodos óxidos

Technology always advances and thus the device miniaturization and improved performance, besides multifunctionality, they become extremely necessary. A wave of research on the area tends to grow in number and importance in today's market, it is necessary to search for new materials, new applicability of the existing ones and new processes for increasingly cheaper costs. Dielectric materials are considered a key element in this sector being the main electrical properties its high dielectric constant and low dielectric loss. The Polymeric Precursor Method appears as a good alternative because is a low cost, simple process with controlled stoichiometry. In this method, two steps were performed. In a first step, the precursor solution was decomposed into powders and in a second step the precursor solution was converted in thin films. In this work, was used the polymeric precursor methods to get thin films where they were heat treated and characterized by XRD, SEM and AFM. We have obtained Bi3NbO7 thin films with good homogeneity and uniform distribution of grains were noted. We observed that the best condition to obtain the tetragonal phase is annealing the film at high temperatures for a longer soaking time and with excess of bismuth. Several oxides electrodes were evaluated aiming to obtain textured dielectric thin films

A influência da temperatura nas impedâncias de sequência de condutores utilizados na rede primária de distribuição

Distribution networks are formed by long lines that carry electricity substations to homes and industries. These lines have associated impedance and depending on operating conditions of the network these impedances may vary. This paper provides a detailed analysis of the effects observed in studies of voltage drop, short circuit and electrical losses, when considered the drivers sequence impedances used in primary distribution network at different temperatures. Therefore, it is initially presented a calculation methodology and details the factors that influence the final values. The methodology presented tackles in a practical way the main factors that directly or indirectly influence the values of the impedances as an emblematic example and will be properly dealt with throughout the paper is the effect of temperature on the values of the sequence impedances. More specifically is dealt with the case of XLPE cables protected, by having a higher maximum operating temperature than the operating temperature of the network. The effects observed in the power flow generated when considering the impedance values at both temperatures were analyzed. The impedance drivers tend to increase with increasing temperature. Thus the impedance of the conductor XLPE protected will tend to be greater for the maximum operating temperature for which the operating temperature of the network, resulting in greater voltage drop and higher electrical losses