931 resultados para Electric insulators and insulation Polymers Testing
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Estudaram-se os efeitos do óxido nitroso (N2O) sobre a concentração alveolar mínima (CAM) do desfluorano. Trinta cães foram distribuídos em dois grupos: desfluorano (GD) e N2O e desfluorano (GDN). Os do GD receberam propofol (8,9±1,65mg/kg) para intubação orotraqueal e após, 11,5V% de desfluorano em 100% de O2. Após 30 minutos, os animais receberam estímulo elétrico e não havendo reação do animal, reduziu-se a concentração em 1,5V%. Repetiu-se o protocolo a cada 15 minutos, cessando-se os estímulos quando observada reação voluntária. Os GDN foram submetidos ao mesmo protocolo, substituindo-se o fluxo diluente por 30% O2 e 70% N2O. Mensuraram-se freqüências cardíaca (FC) e respiratória (FR), pressões arteriais sistólica, diastólica e média (PAS, PAD e PAM), concentração de dióxido de carbono ao final da expiração (ETCO2), saturação de oxihemoglobina (SpO2), temperatura corpórea (TC) e a CAM do desfluorano. Observou-se aumento da FC, ETCO2 e SpO2, e redução da FR e da TC concomitantemente à administração da maior dose de desfluorano, além de redução da CAM do desfluorano. As pressões arteriais diminuíram em M30 aumentando posteriormente. Concluiu-se que o N2O associado ao desfluorano reduz em 16% a CAM do anestésico volátil. Além disso, essa associação promoveu aumento da FC e depressão respiratória.
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A água subterrânea é um importante recurso ao abastecimento público, principalmente para comunidades periféricas em grandes cidades ou pequenos municípios, onde a instalação ou prolongamento de sistemas de distribuição são economicamente inviáveis. Estudos voltados à análise da vulnerabilidade de aquíferos são relevantes para subsídio a políticas públicas em saneamento básico e preservação ambiental. Este estudo contou com o cadastro de 23 poços rasos localizados no município de Caçapava do Sul (RS), onde foram realizadas medidas de resistividade elétrica e cargabilidade por meio de geofísica, e medidas diretas de condutividade hidráulica e sólidos totais dissolvidos. A análise estatística dos dados demonstrou diversos graus de correlação entre parâmetros, basicamente condicionados a fatores geológicos como porosidade, permeabilidade e sólidos totais dissolvidos.
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Objetivou-se no presente trabalho verificar a qualidade do café natural e despolpado durante a secagem em terreiro e secagem com ar aquecido a 40º e 60ºC. O trabalho foi realizado no Departamento de Engenharia e no Pólo de Tecnologia em Pós-Colheita do Café da Universidade Federal de Lavras (UFLA). A colheita do café, cultivar Topázio, foi seletiva. Parte do café foi despolpado e outra parte processado de forma natural. Uma parcela de cada tipo de café foi conduzida para a secagem em terreiro e outra parcela para secagem com temperaturas de 40ºC e 60ºC. Para avaliação da qualidade, foram feitos teste de condutividade elétrica e lixiviação de potássio; determinação de acidez titulável total; teste de acidez graxa; açúcares totais e redutores. Os resultados obtidos permitem concluir que: o tempo para secagem é afetado pelos diferentes tipos de secagem e processamentos; a condutividade elétrica, a lixiviação de potássio, a acidez titulável total e a acidez graxa aumentam com a elevação da temperatura de secagem, independente do tipo de processamento; os açúcares redutores e os açúcares totais diminuem com o aumento da tem peratura de secagem independente do tipo de processamento; a secagem com temperatura de 60ºC afetou negativamente a qualidade do café.
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Dry matter intake (DMI) of coast-cross grazing by crossbred Holstein-Zebu and Zebu lactating cows was calculated using in vitro dry matter digestibility from extrusa (four esophageal fistulated cows) and fecal output estimate with mordent chromium. Pasture was rotationally grazed with three days grazing period and 27 days testing period, adopting a stocking rate of 1.6 and 3.2 cows/ha, during the dry and rainy season respectively. Voluntary DMI was estimated from degradation characteristics using different equations. Predicted coast-cross DMI varied with models. The prediction of tropical forages dry matter intake from equations based in ruminal degradation parameters needs farther investigation before being employed in practice.
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The effect of electrical discharges without thermic effect and of energy field on Meloidogyne incognita Rara 1 larvae elimination in weir water was tested. on an average, 63,22% of larvae were killed by electrical discharges, in comparison with 53,12% of dead larvae in the control (water that received only ammonium sulphate) as an electrolyte. Water exposed to energy fields presented higher percentages of dead larvae (50,01% for electromagnetic field, 43,78% for variable electric field and 40,48% for static electric field) in comparison with control, represented by water without exposition to any energy field and without ammonium sulphate (34,27%).
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Pyroelectric sensors work as a thermal transducer converting the non-quantified thermal flux into the output measurable quantity of electrical charge, voltage or current. Ferroelectric ceramics and ferroelectric polymers have been extensively used as thermal detectors. More recently the research in the field of pyroelectricity has been concentrated on discovering materials with higher figures of merit (FOM), which means better sensing materials. Composite materials obtained with ferroelectric ceramics embedded in polymer host have received great attention because of their formability, mechanical resistance and the possibility to change their dielectric property varying the volume fraction of ceramic particles. In this work composite films made of modified lead titanate (PZ34) and poly(ether-ether-ketone) (PEEK) were characterized and used as sensing element to measure X-ray intensity in the ortovoltage range (120 - 300 kVp). The sensor response varies from 2.70 V to 0.80 V in the energy fluency range of 6.30 to 37.20 W/m(2). Furthermore the absorbed energy was analyzed as a function of the ionizing energy. The results indicate that the PZ34/PEEK composite with 60/40 vol.% can be useful to monitor X-ray radiation therapy.
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The solar events that occurred at the end of October 2003 gave rise to very strong geomagnetic disturbances that peaked twice with Dst values reaching -345 nT around 0000 UT on 30 October and -400 nT around 2300 UT, on the same day. Disturbances in several ionospheric parameters were observed over Brazil. This work will focus on the ionospheric response to the initial westward prompt penetration electric field and on the strong intensification of the equatorial ionization anomaly that occurred because of the electric field polarity reversal that followed in the early morning hours of 29 October. The F layer peak height over the equator first decreased under the strong prompt penetration westward electric field, which was followed by significant height increase under eastward electric field. We have used Sheffield University Plasmasphere Ionosphere Model (SUPIM) with an intensified westward disturbed electric field in the presunrise hours, presumably due to prompt penetration from the magnetosphere, in order to study the effect of such a field in the ionosphere. The simulation results showed that prompt penetration of magnetospheric electric fields of westward polarity to the nightside equatorial region seems to be the most probable cause of the initial F layer height decreases. The intensification of the equatorial ionization anomaly and the unusual enhancement on F layer peak density, which was not modeled by the SUPIM, are explained as caused by the strong eastward electric field that followed the initial phase in combination with a highly variable disturbed meridional/transequatorial wind system as inferred from the F2 layer peak height variations. The highly dynamic wind pattern, with a short-term response (2-4 hours), is compatible with the predictions of some previous theoretical model calculations reported in the literature.
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Newborn Holstein-Friesian and Nelore cattle and Murrah buffalo blood samples were collected for hemograma and serum constituents testing. Results indicated that: 1. buffalo red blood cell (RBC) counts were lower than RBC counts for cattle during the first 30 days after birth; 2. buffalo leukocytes, neutrophil and lymphocyte counts increased in older animals; 3. The highest fibrinogen levels occurred in older calves; 4. buffalo glucose levels were lower than Nelore cattle and decreased in the older calves; 5. buffalo iron, urea, and aspartate aminotransferase levels were higher than in cattle with the highest concentration at the time of birth; 6. cattle bilirubin and alanine aminotranferase levels were higher than buffalo with the highest value at the time of birth; 7. alkaline phosphatase and gammaglutamyltransferase activities were lower in the older calves; 8. buffalo magnesium levels were higher than cattle with lower concentrations at the time of birth..
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A method for studying the technical and economic feasibility of absorption refrigeration systems in compact cogenerators is presented. The system studied consists of an internal combustion engine, an electric generator and a heat exchanger to recover residual heat from the refrigeration water and exhaust gases. As an application, a computer program simulates the cogeneration system in a building which already has 75 kW of installed electric power. The maximum electric and refrigeration demands are 45 kW and 76 kW respectively. This study simulates the system performance, utilizing diesel oil, sugar cane alcohol and natural gas as possible fuels. (C) 1997 Elsevier B.V. Ltd.
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An application of the linear machine one-dimensional analysis method to the modeling of a conventional asynchronous induction motor, considered as a particular case of linear and sectorial machines, is described. A mathematical model for the calculation of the propulsive force developed by this motor, taking into account the transversal edge effect, is derived from the application of the one-dimensional theory and presented in this paper. As an application example, an induction motor is analyzed by means of the one-dimensional theory.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)