996 resultados para matérias estranhas
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O fluxante é uma escória sintética que influencia na qualidade superficial do aço e na estabilidade do processo de lingotamento contínuo. Este produto é aplicado diretamente sobre o aço líquido na região do molde de cobre refrigerado a água e atua diretamente no resfriamento primário do aço. O fluxante tem as propriedades físico-químicas adaptadas para cada tipo de aço e também para as condições de lingotamento. Na superfície do aço líquido, o fluxante funde e forma uma poça líquida, atuando como isolante térmico, protegendo o aço da reoxidação e absorvendo inclusões principalmente de Al2O3. A poça líquida escoa, lubrificando e controlando a transferência de calor na interface entre o molde e a pele de aço em solidificação. O problema de qualidade superficial do aço, quando relacionado ao fluxante, se resume a alarmes de colamento, trincas de quina, marcas de oscilação profundas e trincas longitudinais, sendo este último um problema particular do aço médio carbono. Neste trabalho, foram analisados diferentes fluxantes baseados inicialmente no fluxante comercial aplicado no lingotamento contínuo de placas de aço médio carbono. Todos os fluxantes foram desenvolvidos com composições químicas similares. O objetivo foi avaliar o impacto da substituição de fontes de matérias-primas em diferentes composições de modo a avaliar as propriedades físico-químicas com base no fluxante comercial de referência. Como resultado, de todas as propriedades físico-químicas, foi a temperatura de cristalização que sofreu a alteração mais significativa.
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Contiene: "Manifiesto que o doutor Joam Curvo Semmedo ... faz os amantes da saude & attentos às suas consciencias" (11 p.)
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Es la edición príncipe.
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Mode of access: Internet.
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Este trabalho investiga a cobertura de Ciência, Tecnologia e Inovação (CT&I) nos telejornais brasileiros de canal aberto, no horário nobre (das 19h15 às 22h), para verificar a função educativa da mídia na abordagem de assuntos de CT&I. O corpus desta pesquisa compõe-se de um recorte dos seguintes telejornais: Jornal da Band, Jornal Nacional, Jornal da Record, Jornal da Cultura e SBT Brasil. A proposta foi avaliar, comparativamente, as matérias jornalísticas que tratam especificamente de CT&I, em relação ao formato, à linguagem e aos conteúdos de cada um dos programas estudados. Este trabalho empregou a metodologia de Análise de Discurso de linha Francesa (AD). Esta pesquisa, de natureza qualitativa, também englobou um Estudo de Recepção sobre as reportagens selecionadas. O procedimento utilizado para isso foi o de Grupos Focais. Dessa forma, buscou-se analisar o processo de Comunicação que envolve as matérias telejornalísticas de CT&I das mensagens à recepção. Este estudo verificou que CT&I é um assunto presente nos telejornais brasileiros mesmo quando ocorrem fatos imprevisíveis (de outras editorias) que influenciam significativamente a cobertura dos noticiários televisivos. Constatou também que não há, entre os telejornais selecionados, um padrão de aprofundamento e contextualização dos assuntos CT&I, mas que a abordagem varia até dentro de uma única edição. As emissoras, mesmo reconhecendo a importância de CT&I, ainda oscilam entre uma abordagem contextualizada e a simples descrição do fato principal. A linguagem empregada pelos telejornais para o tratamento de assuntos de Ciência, Tecnologia e Inovação é, predominantemente, clara e simples. No entanto, foi possível verificar algumas nuances, com o uso de termos específicos da linguagem científica sem que a matéria oferecesse qualquer explicação sobre tais conceitos. A experiência dos Grupos Focais revelou que os telespectadores não são passivos em relação aos conteúdos científicos dos programas telejornalísticos. De modo geral, o público se interessa por CT&I e sabe avaliar qualitativamente as matérias. Analisar como as matérias sobre CT&I produzem sentidos e qual a contribuição que estas podem dar à Compreensão Pública da Ciência possibilitou reflexões relevantes sobre as limitações e os potenciais da televisão e das mensagens veiculadas, assim como o interesse e a visão crítica a respeito dos assuntos de CT&I.(AU)
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The article is based fundamentally on the authors' participation in the International Conference “I’ll See You Again in 25 Years: The return of Twin Peaks and generations of cult TV”, held on 21 and 22 May 2015, at the School of Arts and Media, at the University of Salford in England. Starting from there, it makes an irregular discussion of issues and working angles around the television series launched in 1990, a work by David Lynch and Mark Frost. Some issues gain particular attention: 1) the relations of the series to the album Outside (1995) by David Bowie; 2) the population of adult toys related to the series, as derivative products, driven by fans in their most playful exercises of affection and remembrance. Despite the article’s intentionally adopted tone of an “academic report”, it can evoke rich theoretical questions in a field of objects that are in a complex upgrade process and have to be subsequently treated according to more regular methodological procedures, seeking further theoretical and epistemological clarifications
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O presente relatório de projeto de tese aborda o estudo da temática da gestão de armazéns, bem como o estudo de ferramentas de melhoria contínua. Nele, é apresentado um caso de estudo realizado na Nestlé Portugal – Fábrica de Avanca. Numa fase introdutória e preparatória ao projeto, foi realizado um trabalho de pesquisa e compreensão de conhecimentos base para definir quais os objetivos a alcançar e pontos de melhoria. Esta base serviu de pilar de conhecimento para o desenvolvimento do caso de estudo. O caso de estudo consistiu em analisar o sistema de armazenagem, tendo-se para isso simulado o desempenho atual do armazém de modo a otimizar os espaços de armazenagem. Para além disso, avaliou-se o layout do armazém em função da rotatividade dos materiais com recurso à análise ABC e ao estudo de tempos. As oportunidades de melhoria ao nível dos processos de armazenagem refletem-se no sistema de armazenagem em que o ideal seria uma reestruturação ao nível do sistema de armazenagem (estantes com racks convencionais) e ao nível do layout do armazém (segundo a classificação ABC).
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Squeeze
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Relatório de Estágio para a obtenção do grau de Mestre em Ensino da Música
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Brazil is a great ceramic raw materials productor because of the its big number of clay deposits, in various areas of the ceramic industry. Although, the majority of the natural reservations are unknown or not studied yet, so there is no scientific technical dates that can guide their usage and industrial application, as well as the racional and optimazed way of usage by the industrial sector. The state of Maranhão has a gigant mineral wealth as esmectite, bentonite, kaolin, clays, feldspates, marine salt, iron and others, but produce only products with small agregated value compared to the porcelanato, one of the most expensives ceramic cover tiles, the reason for that is the low water absorption (lower than 0,5%), beside present amazing tecnicals features, like mechanical resistence. The main objective of the work is to do the characterization of four clays, with the finallity of find an application by the results and develop formulations to produce porcelanato using these raw materials from Timon-MA. For this were made the raw materials characterization using X ray fluorecence; X ray diffraction; Differencial thermal analysis; Dilatometric analysis and Tecnological properties, planing three formulations that were sinterized at six different temperatures: 1150, 1170, 1190, 1210, 1230 and 1250ºC for 7 minutes. After the sinteratization, the samples were submitted to tension resistance analysis. Were attained two formulations with the requested properties to produce porcelanato
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The ceramics industry in Piauí is nowadays with 55 industries where 11 are in Teresina which is the mainstream of the state, producing 55 million shingles; in which 10 % is of this production is wasted being sometimes thrown on the margins of rivers, roads and highways provoking an environmental degradation. The main goal of this work is to verify the potential of producing semi porous ceramic using grog of shingles, on the first part of this work bodies-of-proof were produced from a basic formula of an industry, doping it with 5 %, 10 %, 15 % and 20 % in mass and in the second part of this work some bodies-of-proof were produced from a formula where one raw material was substituted by 50 % of grog and another substituting it all by grog, bodies-of-proof made of a basic formula previously announced was used for experiment control.The grog and the raw materials were characterized by: particle size analysis , thermal differential analysis, X ray diffraction , X ray fluorescence, an thermal gravimetric analysis and rational analyses. The bodies-of-proof were sintetisized in an industrial oven obeying the normal cycle adopted by an industry, with peak temperatures of 1135 oC and a fast burning cycle of 25 minutes having as energetic fuel liquefied petroleum gas . The pieces that were obtained by this were submersed in rehearsed physics of: water absorption of, apparent specific mass, apparent porosity, lineal retraction, rupture tension to the flexural and dilatometry; mineralogical analysis for X ray diffraction; and microstructural for electronic microscope of sweeping. For all the formulas with addition of grog, superior priorities to the requested by the requirements for semi porous and for the formula to F2-2,5 superior priorities to standard formulas which justifies the incorporation of the shingles in mass for the semi porous ceramic
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Structural changes in waste for zeolites synthesis are subject of many studies carried out in the synthesis of molecular sieves. These materials are named molecular sieves because they have well defined pore sizes and they have the capacity of select molecules by its size. In this work, it was studied the synthesis processes of two types of molecular sieves: pillared acid clays using as starting material one natural montmorillonite clay and the synthesis of zeolites from a silico-aluminous residue. This residue is a byproduct of the extraction of lithium -spodumene. The preparation of pillared acid clays was performed in two steps: 1° acid treatment of clay samples (time and temperature studies) and 2°pilarization of them with Al13 (Keggin ion). The temperature and acid concentration affect the removal of cations in the structure and porosity of the material obtained. The analysis of X-ray diffraction (XRD) and infrared spectroscopy (IR), showed that increasing the severity of the acid treatment compromises the structural material. Also the pore size distribution is approximately uniform. Despite presenting a structural disorganization, the samples were pillared. As evidenced by XRD increasing the basal spacing, specific area and uniform porosity by adsorption of N2. Regarding the microporous molecular sieves were synthesized zeolites A and NaP1 from a silico-aluminous residue, a byproduct of extracting lithium. The temperature and time of agitation during the synthesis were the most important factors for obtaining zeolite A. The aging of the gel and the highest crystallization time promoted the formation of zeolite NaP1 using a Si / Al ratio = 3.2
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Piauí state is a major producer of traditional red ceramic burning as bricks, tiles and ceramic tiles, with its main production center located in the city of Teresina. The state has large reserves of raw materials that can be used in the ceramic coating as clays, quartz, talc and carbonates. However, in the preparation of ceramic bodies using only a mixture of clays with different characteristics. The study aims to evaluate the effect of adding two types of carbonates in the ceramic semiporous mass coating produced in Piauí and then to verify the potential use of these carbonates as supplementary raw material product manufactured or the feasibility of obtaining a ceramic plate that meets the specifications for the porous coating. For this, were characterized the ceramic Piauí coating mass, a calcitic carbonate and a dolomitic, were made in the levels of 2, 4, 8, 16, and 32%. The masses were formed by pressing and burneds in two environments: a laboratory furnace (1080°C, 1120°C, 1140°C, and 1160°C) and an industrial furnace (1140°C). Then, following tests of linear shrinkage water absorption, apparent porosity, bulk density and flexural strength. Furthermore, the fired specimens were tested for their macrostructure and microstructure. The results showed the possibility of using the carbonate in ceramic mass flooring produced in Piauí, as added in small proportions improved dimensional stability and increased mechanical strength of ceramics pieces. It also proved itself possible to produce porous coating when added in higher levels
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The dielectric porcelain is usually obtained by mixing various raw materials proportions and is used in the production of electronic equipment for various applications, from capacitors of high and low Power to insulators for low, medium, high and extra high voltage, which are used in distribution lines and transmission of electricity.This work was directed to the s tudy of technological properties of technic porcelain, made from raw materials extracted from pegmatites found in the regions of Seridó and the Alto Oeste of Rio Grande do Norte, which are made of kaolin, quartz and feldspar, abundant and high quality in these regions. The technic ceramics were obtained by mixing in appropriate levels, kaolin, feldspar, quartz and clay, the last item from a pottery in the city of Sao Gonçalo do Amarante, Rio Grande do Norte. During the development the following characterizations correlated to raw materials were made: laser particle sizing, x-ray diffraction, DTA and TG. The compositions studied were formed by uniaxial pressing at a pressure of 50 MPa and sintered at temperatures ranging from 1150 to 1350ºC and levels (times) of sintering between 30, 60, 90 and 120 minutes. The characterization of the samples were taken from the analysis of weight loss, linear shrinkage, porosity, stoneware curve, bulk density, flexural strength of three points, SEM and X-ray diffraction, TMA, Dielectric and cross Resistivity. The studied materials can be employed in producing the objects used in electrical engineering such as: insulators for low, medium and high-voltage electrical systems, command devices, bushing insulation for transformers, power capacitors, spark plugs, receptacles for fluorescent and incandescent light bulbs and others
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In the search for products that act as corrosion inhibitors and do not cause environmental, impact the use of plant extracts as corrosion inhibitors is becoming a promising alternative. In this work the efficiency of polar extracts (ethanol extracts) obtained from the plants Anacardium occidentale Linn (AO) and Phyllantus amarus Schum. & Thonn (PA) as corrosion inhibitors were evaluated in different concentrations. For that AO and PA extracts were solubilized in the microemulsion systems (SME) containing saponified coconut oil as surfactant (SME -OCS and SME-OCS-1) in saline (NaCl 3,5 %) solution, which was also used as electrolyte. Both SME-OCS and SME-OCS-1 were characterized by surface tension and viscosity methods showing a Newtonian fluid behavior. The SME-OCS and SME-OCS-1 systems satisfactorily solubilized the polar extracts AO and PA with measurements carried out by ultraviolet spectroscopy. The measurements of corrosion inhibition efficiencies were performed by the electrochemical linear polarization resistance (LPR) technique as well as weight loss, on the surface of AISI 1020 carbon steel. The maximum corrosion inhibition efficiencies were determined by extrapolation of Tafel plots, showing the following values: 95,6 % for the system SME-OCS-AO, 98,9 % for the system SME-OCS-AO-1 and 93,4 % for the system SME-OCS-PA