RESUMO
ABSTRACT For combustion engines to perform well, it is necessary that the fuel used be of high quality. Fuel quality can be analyzed through different physicochemical properties. This study presents comparisons between the values presented in literature, legislation and those obtained through experimental tests of different biodiesel samples. Biodiesel is a promising alternative of renewable energy obtained from raw material. The properties observed in this study are: Viscosity, density, cloud point, pour point and calorific value. The data explored by this work aims to bring solidification to the methodologies and equipment necessary for a better characterization of biodiesel.
Assuntos
Óleos de Plantas , Biocombustíveis , Energia Renovável , Gás NaturalRESUMO
We induce nanometer-scale surface deformation by exploiting momentum conservation of the interaction between laser light and dielectric liquids. The effect of radiation force at the air-liquid interface is quantitatively assessed for fluids with different density, viscosity and surface tension. The imparted pressure on the liquids by continuous or pulsed laser light excitation is fully described by the Helmholtz electromagnetic force density.
RESUMO
Strong light absorption and high levels of singlet oxygen production indicate erythrosin B as a viable candidate as a photosensitizer in photodynamic therapy or photodynamic inactivation of microorganisms. Under light irradiation, erythrosin B undergoes a photobleaching process that can decrease the production of singlet oxygen. In this paper, we use thermal lens spectroscopy to investigate photobleaching in micellar solutions of erythrosin ester derivatives: methyl, butyl, and decyl esters in low concentrations of non-ionic micellar aqueous solutions. Using a previously developed thermal lens model, it was possible to determine the photobleaching rate and fluorescence quantum efficiency for dye-micelle solutions. The results suggest that photobleaching is related to the intensity of the dye-micelle interaction and demonstrate that the thermal lens technique can be used as a sensitive tool for quantitative measurement of photochemical properties in very diluted solutions.