232 resultados para POLYCARBONATE


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The present paper examines building integrated solar collectors with absorbers of polymeric materials. Efficiency measurements of façade-integrated collectors with non-selective black and spectrally selective coloured absorbers are carried out. The performance of the polymeric absorber was compared with solar glass and polycarbonate twin-wall sheets as collector cover. Simulations demonstrate a high solar fraction for a solar combisystem with façade collectors for a well-insulated house in a Nordic climate. Two examples of house concepts with façade collectors are presented which address a new type of customer than the solar enthusiasts with special interest in renewable energy

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Tangara da Serra is located on southwestern Mato Grosso and is found to be on the route of pollutants dispersion originated in the Legal Amazon s deforestation area. This region has also a wide area of sugarcane culture, setting this site quite exposed to atmospheric pollutants. The objective of this work was to evaluate the genotoxicity of three different concentrations of organic particulate matter which was collected from August through December / 2008 in Tangara da Serra, using micronucleus test in Tradescantia pallida (Trad-MCN). The levels of particulate matter less than 10μm (MP10) and black carbon (BC) collected on the Teflon and polycarbonate filters were determined as well. Also, the alkanes and polycyclic aromatic hydrocarbons (PAHs) were identified and quantified on the samples from the burning period by gas chromatography detector with flame ionization detection (GC-FID). The results from the analyzing of alkanes indicate an antropic influence. Among the PAHs, the retene was the one found on the higher quantity and it is an indicator of biomass burning. The compounds indene(1,2,3-cd)pyrene and benzo(k)fluoranthene were identified on the samples and are considered to be potentially mutagenic and carcinogenic. By using Trad-MCN, it was observed a significant increase on the micronucleus frequency during the burning period, and this fact can be related to the mutagenic PAHs which were found on such extracts. When the period of less burnings is analyzed and compared to the negative control group, it was noted that there was no significant difference on the micronuclei rate. On the other hand, when the higher burning period is analyzed, statistically significant differences were evident. This study showed that the Trad-MCN was sensible and efficient on evaluating the genotoxicity potencial of organic matter from biomass burning, and also, emphasizes the importance of performing a chemical composition analysis in order to achieve a complete diagnosis on environmental risk control

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It was studied a system for heating water to be used to obtain water for bathing at home, the absorbing surface of the collector is formed by one plate of polycarbonate. The polycarbonate plate has 6 mm thick, 1.050 mm wide and 1.500 mm long with an area equal to 1,575 m². The plate was attached by its edges parallel to PVC tubes of 32 mm. The system worked under the thermo-siphon and was tested for two configurations: plate absorber with and without isolation of EPS of 30 mm thick on the bottom surface in order to minimize heat losses from the bottom. The tank's thermal heating system is alternative and low cost, since it was constructed from a polyethylene reservoir for water storage, with a volume of 200 liters. Will present data on the thermal efficiency, heat loss, water temperature of thermal reservoir at the end of the process simulation and baths. Will be demonstrated the feasibility of thermal, economic and material pickup proposed for the intended purpose.

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

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Liposomes of soya phosphatidylcholine, cholesterol, and stearylamine (molar ratio 6/3/1) and 0.1% alpha-tocopherol were prepared by the extrusion of multilamellar vesicles through 0.2-mu m polycarbonate membrane. Liposomes were characterized by electron transmission microscopy, and the mean structure diameter was 278 nm. The encapsulation efficiency obtained was 12.73%. The topical anti-inflammatory effect was evaluated in vivo by the cotton pellet granuloma method. We analyzed free piroxicam at 4 mg/kg, piroxicam encapsulated in liposomes added to 1.5% hydroxyethylcellulose (HEC) gel at 1.6 mg/kg, and piroxicam encapsulated in liposomes added to HEC gel at 4 mg/kg; the inhibition of inflammation obtained was 21.1%, 32.8%, and 47.4%, respectively. These results showed that the encapsulation of piroxicam produced an increase of topical anti-inflammatory effect, suggesting that the inhibition of inflammation can be obtained with lower drug concentrations.

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

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

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Different procedures for obtaining a needle biosensor for the determination of glucose to be inserted subcutaneously in vivo, have been compared. Platinum wires with a diameter of 75 mum, teflon-coated were inserted in hypodermic needles and fixed with a two-component epoxy resin. Using a dip-coating procedure, several layers were deposited on electrodes. The first coating was cellulose acetate, the second was immobilized glucose oxidase (GOD) mixed with bovine serum albumin (BSA) and glutaraldheyde, the third coating was a polyurethane coating obtained with commercially available products. A large number of electrodes have been tried and statistically evaluated but they seem to be affected by poor reproducibility evidenced by a large spreading in successive calibration curves. Then, the polyurethane coating has been replaced by a thin polycarbonate membrane salinized and fixed on the tip of the needle. Reproducible results were achieved and first results of in vivo measurements on rabbits are reported.

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Pós-graduação em Artes - IA

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Pós-graduação em Física - FEG

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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AIM: To evaluate the staining of esthetic orthodontic brackets by plaque disclosing solutions. METHODS: Two types of brackets manufactured by GAC/DENTSPLY(r) were evaluated: ceramic (n=30) and polycarbonate (n=30). The brackets were divided into 6 groups. Two control groups (n=6) were immersed in absolute ethanol: GI - ceramic brackets and GII - polycarbonate brackets. Four experimental groups (n=12) were immersed in different plaque disclosing solutions: GIII (ceramic brackets) and GIV (polycarbonate brackets) were immersed in Replak(r); GV (ceramic brackets) and GVI (polycarbonate brackets) were immersed in Replasul "S"(r). Relative quantitative analysis of the influence of plaque disclosing tablets on bracket staining was performed using reflectance spectrophotometry of stain deposition. Exploratory analysis of the data was performed using Analysis of Variance (ANOVA) in a 2x2 factorial setup (bracket x immersion) with additional treatments (controls). RESULTS: The results demonstrated that the ceramic brackets presented the highest amount of staining when Replasul "S"(r) was used (pd"0.05). However, when Replak(r) was used, no statistically significant difference was found in comparison with the control group (p>0.05). For polycarbonate brackets, staining was detected for both disclosing solutions (p>0.05). CONCLUSIONS: The disclosing solutions caused stain formation on polycarbonate brackets and, under the tested conditions, use of Replak(r) on ceramic brackets did not cause staining.