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O presente trabalho consiste em utilizar energia solar fotovoltaica integrada ao serviço auxiliar de uma subestação (88kV/13,8kV), o qual fornece alimentação aos equipamentos essenciais para proteção, supervisão e controle, e para os serviços básicos como iluminação, tomadas, sistema de climatização da casa de controle, motores do sistema de arrefecimento dos transformadores, desumidificação dos painéis de comando, bombas de água, dentre outros. A partir dos cálculos realizados, foi observado que o retorno dos investimentos financeiros dados para a instalação proposta se dá em menos de 7 anos – o que destaca a viabilidade econômica, social e, principalmente, sustentável do projeto.

Turbine and bushing bearing are the most critical components of high-speed machines. This article describes the design of a high-speed turbine supported by hydrodynamic bearings. The mathematical dimensioning and the FEM analysis are presented to validate the mechanical strength of the turbine and the bushing bearing models. Fatigue life and factor of safety were also determined. The simulations showed that the maximum Von Mises stress values obtained are associated to the centrifugal force generated by the system rotational movement. The results variation was mainly due to the properties of the materials proposed. For the turbine, 7075-T6 aluminum alloy and SAE 4340 steel obtained satisfactory behavior under a constant operating speed of 30,000 RPM. For the hydrodynamic bearing, the TM23 bronze alloy exhibited excellent results, without fracture, and low mechanical deformation. The models exhibited a great potential employment in several applications, such as biogas systems to generate electrical energy, and educational test bench for thermodynamic and tribological simulations.

Titanium dioxide ceramic coatings have been used as catalysts in green technologies for water treatment. However, without the presence of a dopant, its photocatalytic activity is limited to the ultraviolet radiation region. The photocatalytic activity and the structural characteristics of undoped and sulfur-doped TiO2 films grown at 400 °C by metallorganic chemical vapor deposition (MOCVD) were studied. The photocatalytic behavior of the films was evaluated by methyl orange dye degradation under visible light. The results suggested the substitution of Ti4+ cations by S6+ ions into TiO2 structure of the doped samples. SO42− groups were observed on the surface. S-TiO2 film exhibited good photocatalytic activity under visible light irradiation, and the luminous intensity strongly influences the photocatalytic behavior of the S-TiO2 films. The results supported the idea that the sulfur-doped TiO2 films grown by MOCVD may be promising catalysts for water treatment under sunlight or visible light bulbs.

The present study evaluated the main factors that influence the photocatalytic activity of titanium dioxide (TiO2) films grown by metalorganic chemical vapor deposition (MOCVD) at 400 and 500 °C, in different growth times. The photocatalytic behavior was analyzed by measuring the methyl orange dye degradation at different pH values. Structural and morphological characteristics, and the recyclability of the catalysts for several cycles were also investigated. Anatase phase was identified in all films. The higher photodegradation performances were obtained at acidic pH. The results demonstrated that the photocatalyst thickness is an important parameter in heterogenous photocatalysis. The best photocatalytic result occurred for the 395 nm-thick TiO2 film grown at 400 °C, which presented 65.3% of the dye degradation under UV light. The recyclability experiments demonstrated that the TiO2 films grown by MOCVD present a great stability after several photocatalytic cycles, which allows their practical application for water treatment with high efficiency.

This paper proposed to elaborate a navigation system for an autonomous mobile robot, able to deviate from obstacles, from the study and application of Fuzzy Logic. With the algorithm in operation, it was verified that the Fuzzy logic offers a smoother transition in the movements. In order to validate the efficiency of the navigation system created, simulations were performed with the robot according to the rules inserted in the Fuzzy controller, where the input values of the sensors and the output values in the PWM of the board were analyzed. The results obtained were consistent with the responses given by the simulation in MatLab, following the same trend of behavior. With the realization of this project, it was concluded that the Fuzzy methodology presents a solution to the problems of navigation in real environments, allowing to implement a controller for an autonomous robot that can deflect obstacles avoiding their collision. One of the problems encountered is the angle of actuation of the ultrasonic sensors. This type of sensor works with an angle of actuation of 15◦, which leaves the robot with a low vision area in the use of three sensors. As a result, there may be no reading on objects entering zones without detection, leading to a collision with these obstacles. The responses were satisfactory, following the same trend behavior of the simulations of the Fuzzy controller.

TiO2 films were sulfur-doped through an alternative route based on the decomposition of H2 S at low temperatures. MOCVD technique was used to grown the films on borosilicate glass substrates at 400 °C. The doping was carried out at 50, 100 and 150 °C under a mixture of H 2-2%v.H2S. SO42− groups were observed in the surface revealing the substitution of Ti4+ by S6+ . Superficial roughness and wettability were also modified by the formation of these sulfate groups on the surface. Photocatalytic experiments of methyl-orange dye decolorization under visible light indicated that the 8 at.% S-TiO 2 film exhibited the highest photocatalytic activity, with 72.1% of dye decolorization. The results suggest that the exposition of TiO2 films to the mixture H2-H2S at low temperatures is an efficient method of doping. These films allow the decolorization of the dye under visible light irradiation, which enable its practical use under sunlight or even indoor.

Turbine and bushing bearing are the most critical components of high-speed machines. This paper describes the design of a high-speed turbine supported by hydrodynamic bearings. The mathematical dimensioning and the FEM analysis are presented to validate the mechanical strength of the turbine and the bushing bearing models. Fatigue life and factor of safety are also determined. The simulations show that the maximum von Mises stress values obtained are associated with the centrifugal force generated by the system rotational movement. The results variation is mainly due to the properties of the materials proposed. For the turbine, 7075-T6 aluminum alloy and SAE 4340 steel obtained satisfactory behavior under a constant operating speed of 30,000 RPM. For the hydrodynamic bearing, the TM23 bronze alloy exhibited excellent results, without fracture, and low mechanical deformation. The models exhibited a great potential employment in several applications, such as biogas systems to generate electrical energy, and educational test bench for thermodynamic and tribological simulations.

In the present study a real-time capacitive sensor based on a capacitance step method is designed, developed and applied on measuring the liquid level by immersion. The capacitive sensor consists of two electrodes from copper plated phenolite plates separated by a gap distance and mounted inside a non-conductive storage tank. Water is used as the dielectric material. The analyzed sensor behavior with liquid level variation is semi-linear and obtained in function of the output voltage variation by using proper signal conditioning circuit. For converting the voltage variation into level variation, a parallel R–C circuit is used instead of conventional bridge circuit. Under suitable parameter settings it provided good reading accuracy. The experimental results demonstrate the high efficiency of the proposed model, which confirm the satisfactory performance of the capacitive sensor for liquid level measurement. The sensor presents an excellent ease of construction and installation, linked to the good measurements precision and high autonomy of system operation. The behavior experiments under different salt concentrations show that the water chemical composition does not interfere on the sensor operation. The proposed model exhibits a promising employment in several applications, such as control equipment for irrigation, biomedical area—in the interaction between antibody–antigen or protein-DNA, aerospace and pharmaceutical industry, gas sensors, and automation solutions.

The surface chemistry and recyclability of sulfur-doped titanium dioxide (TiO2) films was evaluated. The photocatalysts were grown by metalorganic chemical vapor deposition (MOCVD) at 400 °C. The films were sulfur-doped at 50 °C by using hydrogen sulfide (H2S) as sulfur source. The photocatalytic behavior of the films was measure by monitoring the methyl orange dye decolorization under visible light for several cycles. The films are formed only for the anatase crystalline phase. The results demonstrated that no structural modifications or significant differences in the morphology of the films occurred after their use. The sulfur-doped TiO2 films presented good photocatalytic activity, with an efficiency of 72.1% under visible light in its first use. The durability experiments suggest that even with the dye impregnation on the catalyst surface, the photocatalytic activity of the S-doped TiO2 films remained around 70% in the first 3 cycles, which allows their practical application for water treatment and purification under sunlight.

Filmes finos de dióxido de titânio vêm sendo utilizados em diversas aplicações tecnológicas, desde revestimentos autolimpantes e bactericidas, até células solares e fotocatalisadores. O TiO2 apresenta polimorfismo em três fases cristalinas: anatase, broquita e rutilo, cada uma com propriedades físicas e químicas específicas. O presente trabalho apresenta o resultado do somatório de experiências desenvolvidas pelo grupo de pesquisa do Laboratório de Filmes Finos e Nanoestruturas do IPEN (Brasil), analisando por meio dos respectivos estudos a influência da temperatura de deposição e substrato sobre a morfologia dos filmes obtidos. Os filmes de TiO2 foram crescidos através da técnica de deposição química de organometálicos em fase vapor (MOCVD), sobre substratos de borossilicato, a 400 e 500°C, e substratos Si(100) nas temperaturas de 400, 500, 600 e 700°C. Observando-se os espectros de difração de raios-X dos filmes, foi verificado que a 400 e 500°C há a presença apenas da fase anatase, enquanto que a 600°C pode-se identificar as fases anatase e rutilo. O filme crescido a 700°C apresentou, além de anatase e rutilo, a fase broquita. Foi observadoque a velocidade de crescimento dos filmes aumenta com a temperatura até 500°C e, a partir disso diminui, aspecto característico da curva do processo, que indica haver uma mudança de mecanismo de crescimento