Sensoriamento óptico quase-distribuído aplicado ao monitoramento de trocadores de calor de usinas hidrelétricas

This work aims to develop optical sensors for temperature monitoring in hydroelectric power plant heat exchangers. The proposed sensors are based on the Fiber Bragg Gratings technology. First of all, a prototype with three sensors inscribed in a same fiber was developed. This fiber was then fixed to a conventional Pt100 sensor rod and inserted in a thermowell. The ensemble was then calibrated in a workbench, presenting a maximum combined uncertainty of 2,06 °C. The sensor was installed in one of the heat exchangers of the Salto Osório’s hydroelectric power plant. This power plant is situated in the Iguaçu river, at the Paraná state. Despite the satisfactory results, the sensor was improved to a second version. In this, fifteen optical Bragg sensors were inscribed in a same fiber. The fixation with a conventional sensor was no longer necessary, because the first version results comproved the efficiency and response time in comparison to a conventional sensor. For this reason, it was decided to position the fiber inside a stainless steel rod, due to his low thermal expansion coefficient and high corrosion immunity. The utilization of fifteen fiber Bragg gratings aims to improve the sensor spatial resolution. Therefore, measurements every ten centimeters with respect to the heat exchanger’s height are possible. This provides the generation of a thermal map of the heat exchanger’s surface, which can be used for determination of possible points of obstruction in the hydraulic circuit of the heat exchanger. The heat exchanger’s obstruction in hydroelectric power plants usually occur by bio-fouling, and has direct influence in the generator’s cooling system efficiency. The obtained results have demonstrated the feasibility in application of the optical sensors technology in hydroelectric power plants.

Tiras cômicas online: mediação e interações na linguagem das tiras

The study aims to analyze comic strips on the internet, from three different artists: Carlos Ruas, creator of "Um Sábado Qualquer", André Farias, of "Vida de Suporte," and William Leite, author of "Willtirando". The discussion covers the relationship between comics and technology by analyzing the comic strip and the construction of its meaning. The qualitative reflection is aggregated by quantitative data, through which the work shows possible outcomes for the language of the online comic strips, such as the expansion in the format; increased hybridization with various types of images; and the approach phenomenon between the spheres author/reader in digital format. Productions of a most unusual kind also were discussed: the digital comic strips, that incorporate animated effects on its narrative. At the end of the study, we present an online comic strip prototype from the most popular formats used by the authors, in order to reiterate the nature of the comic strips: a brief narrative whose outcome is unexpected and results in humor.