Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
Search results
52 records were found.
Cosolvents have been used in remediation of source zones at sites contaminated with non-aqueous phase liquid (NAPL), because of their ability to increase the solubility of NAPL constituents. Upon depletion of NAPL mass from the treated zone, complete recovery of cosolvent is generally required considering the possible toxicity to the indigenous microbial communities from chemicals used as cosolvent. Since cosolvent flushing involves enhanced extraction of NAPL mass, additional above ground treatment of waste fluids is required. The laboratory research conducted in this thesis focused on ways to eliminate these two needs. First, a biofriendly cosolvent, ethyl lactate (EL), was found to be very efficient in recovering DNAPL mass in source zone. The residual amount of EL not only poses no harm to indigenous microbial population in a DNAPL...
Electron microscope analysis has shown that nanoscale phase separation occurs in the SnO2-doped preform and fibers after UV exposure. This phenomenon has been observed only in Sn-doped germanosilicate and phosphosilicate core glasses when the SnO2 concentration is high.
Sn-doped silicate fibers exhibit extremely high photosensitivity when exposed to 248 nm KrF excimer laser. Electron micrograph probing has shown that nanoscale phase separation occurs in fibers and fiber preforms after UV exposure. This phenomenon has been observed only in SnO codoped glasses are the first optical fibers to exhibit phase separation.
Research on fluorescence-based integrated optical immunoassay multisensing systems has gained growing interest in the last ten years because these sensors offer high sensitivity and good specificity, can simultaneously detect multiple analytes in a single measurement and are fast, robust and cost-effective [1-5]. Therefore they have the potential to replace conventional chromatographic techniques as the monitoring systems for the rapid assessment of pollution in water. These highly multiplexed analytical systems are also in demand in other fields such as clinical diagnostics and forensic science. This research work presents advances in multi-analyte integrated optical fluorescence-based sensors, their integration into a novel, reconfigurable, multi-bio-sensing system and their use in detecting organic pollutants in river water.
A fibre-pigtailed dual-sensitivity integrated optical Mach-Zehnder Interferometer sensor chip for liquid analytes is described. Thin overlays of Ta2O5 and reference structures have been integrated to enhance sensitivity and compensate for drift and attenuation.
A fibre-pigtailed dual-sensitivity integrated optical Mach-Zehnder Interferometer sensor chip for liquid analytes is described. Thin overlays of Ta2O5 and reference structures have been integrated to enhance sensitivity and compensate for drift and attenuation.
Near-Infrared (NIR) spectroscopy is a powerful tool for chemical analysis in applications ranging from biomedicine to analysis of food products and textiles [1]. However, molar absorptivities in this spectral region are usually weak, so that high-sensitivity measurement devices are required. Optical waveguides provide for highly sensitive attenuated total reflection (ATR) spectroscopy in a robust mass-producible format, and allow for ultra-small sample volume, due to the 100 nm scale extent of the evanescent field, and the potential for lab-on-chip integration.
Electrokinetic phenomena associated with fluid flow in micro-channels have been studied for different applications. For example, electro-osmotic flow pumps involve driving a fluid along a narrow channel by applying an electric field along the length of the channel. This process is reversible, thus it is possible to use for electric energy generation where driving an electrolyte fluid along a narrow channel by a pressure difference at both sides of the channel results in an electric potential along the length of the channel. Such electric potential can then be harnessed to drive an electric current through an external load. Theoretical conversion efficiencies of up to 12% have been estimated, and experiments have claimed 3% efficiency using flat 75 nm microfabricated channels on silicon.
