Sistema de destilação solar com pré-aquecimento em concentrador cilindro parabólico

Due to the increasing need to promote the use of resources that support the environment and the clean industry, the science has developed in the area of natural resource use as well as enhanced use of the renewable energy sources. Considering also the great need for clean water and wide availability of salt or brackish water, added to the great solar energy potential in northeastern of the Brazil, it was developed a solar distiller whose main difference is its system of pre-solar heating also. From experimental adjustments, the system was developed by the use of a cylindrical solar concentrator coupled to a conventional distiller. The system is designed such that attempt to facilitate the process termination trap to ensure constant movement of the fluid mass and thus enable higher temperatures to the system and thus fetch a higher amount of distillate collected. In a stage of the experiment were used a forced circulation to try to further increase the amount of energy exchange system. To develop the study were set up four settings for comparison in which one was only distiller simple as basic parameter, the second proposed configuration were with the coupling of the concentration triggered manually every 30 minutes to monitor the sun, the third configuration occurred with automatic triggering of a timer, and the fourth configuration was also used a pumping system that tried to improve the circulation of the fluid. With the comparative analysis of the results showed a gain in the amount of distillate system, especially in the forced model

Síntese hidrotérmica assistida por micro-ondas de tiO2, e aplicação em nanocompósito

In recent decades have seen a sharp growth in the study area of nanoscience and nanotechnology and is included in this area, the study of nanocomposites with self-cleaning properties. Since titanium dioxide (TiO2) has high photocatalytic activity and also antimicrobial, self-cleaning surfaces in your application has been explored. In this study a comparison was made between two synthesis routes to obtain TiO2 nanoparticles by hydrothermal method assisted by microwave. And after analysis of XRD and SEM was considered the best material for use in nanocomposites. It was deposited nanocomposite film of poly (dimethyl siloxane) (PDMS) with 0.5, 1, 1.5 and 2% by weight of nanoparticles of titanium dioxide (TiO2) by the spraying method. The nanocomposite was diluted with hexane and the suspension was deposited onto glass substrate, followed by curing in an oven with forced air circulation. The photocatalytic activity of the nanocomposite impregnated with methylene blue was evaluated by UV- vis spectroscopy from the intensity variation of absorption main peak at 660nm with time of exposure to the UV chamber. Changes in the contact angle and microhardness were analyzed before and after UV aging test. The effect of ultraviolet radiation on the chemical structure of the PDMS matrix was evaluated by spectrophotometry Fourier transform infrared (FTIR).The results indicated that the addition of TiO2 nanoparticles in the coating PDMS gave high photocatalytic activity in the decomposition of methylene blue, an important characteristic for the development of self-cleaning coatings