Submitted by William Justo Figueiro (williamjf) on 2015-07-03T14:07:55Z No. of bitstreams: 1 35.pdf: 3528795 bytes, checksum: 41798f18331f2ad126b036c9527cb986 (MD5) / Made available in DSpace on 2015-07-03T14:07:55Z (GMT). No. of bitstreams: 1 35.pdf: 3528795 bytes, checksum: 41798f18331f2ad126b036c9527cb986 (MD5) Previous issue date: 2012-06-22 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / As atividades de produção, manutenção e operação do ambiente construído estão relacionadas com, aproximadamente, metade das exigências de extração e produção de materiais naturais, bem como similar parcela dos resíduos gerados pela sociedade. A construção civil está vivenciando a alteração de alguns paradigmas, com a inclusão dos requisitos de desempenho no processo de projeto, sendo um dos elementos importantes, o conforto acústico. As soluções convencionais têm custos elevados. O objetivo do trabalho é investigar o potencial de absorção acústica de compósitos de argamassa com substituição parcial da areia por alguns resíduos: da agroindústria (casca de arroz), da indústria de calçados (contraforte de calçados) e da construção (compensado resinado). Foram investigados vários teores de resíduos (0%, 5%, 10%, 25% e 50%). A medição da absorção acústica foi efetuada através de tubo de impedância, com amostras de Ø100mm. Os resultados demonstraram que os compósitos com adição de resíduos apresentaram coeficientes de absorção acústica superiores aos corpos de prova de referência, aumentando a capacidade isolante desses compósitos. A casca de arroz se destacou entre os resíduos, seguida do compensado resinado e do contraforte. Visto que não há custos significativos para incorporação destes resíduos, pode-se concluir que os objetivos foram atingidos e que este estudo contribui para a melhoria do conforto acústico e para a redução do impacto dos resíduos no meio ambiente. / Production the activities of, maintenance and operation of the built environment are related to approximately half of the requirements for extraction and production of materials as well as similar proportion of raw waste generated by society. The construction industry is changes experiencing some paradigms, with the inclusion of performance requirements in the design process. One of them is the acoustical comfort. The objective of this study is to investigate the potential of acoustic insulation composites of mortar with replacement of sand for a few residues: agro-industry (rice husk), shoe industry (shoes’ foothills) and construction (forms of plywood). It was investigated some residues taxes (0%, 5%, 10%, 25%, 50%). The measurement of the acoustic absorption was carried out through the method using an impedance tube with sample size of Ø100mm. The results show that the compounds with the addition of wastes have higher sound absorption coefficients than the test was the best references, increasing the absorption capacity of these compounds. The rice husk was the best among the residuals, followed by the plywood waste and by of shoes’ foothills. Since there is no cost for incorporation of these residues, it can be concluded that the objectives have been achieved and that this study has contributed to improving the acoustic comfort and for the reduction of the impact of residues on the environment.

Carbon nano tubes (CNT’s) are promising candidates for several sensor applications such as optical sensors, strain gauges or flow sensors. For certain sensor structures liquid CNT dispersions are required. These are important not only for the realization of CNT-films for sensors like strain gauges but also for technological processes such as dielectrophoresis. CNT-films are realized by deposing the dispersion on a carrier material followed by a drying process. The dispersion properties depend on several parameters like CNT concentration, surfactant concentration, sonication time, centrifugation time, storing time and other parameters. Methods for characterization of dispersions are up to now limited to UV/VIS spectroscopy. This is generally limited to low CNT concentrations. This paper discusses the possibility to use impedance spectroscopy as characterization method for the stability of the dispersions. The impedance of the dispersion was measured using a conductivity measurement cell with platinum electrodes. The behavior of characteristic points of the impedance spectrum was investigated for three identically prepared samples during 7 days of storing time. The systematic trend observed is definitively larger than the variance between different samples. With increasing time after preparation the CNT fallout will increase and the amount of deposable CNT’s will decrease. The decreasing imaginary part indicates an easier diffusion of surfactant molecules because they are not longer attached to CNT’s.