A influência do tamanho de grão ferrítico da peça na integridade superficial de peças erodidas

Pós-graduação em Engenharia Mecânica - FEIS

Estudo das propriedades de materiais supercondutores

Superconductivity was discovered by the dutch physicist Heike Kamerlingh Onnes (1853

Propriedades ópticas e elétricas de materiais híbridos de sílica/orgânico à base de GPTS:TEOS preparados pelo método sol-gel

Fabrication of optoelectronic devices requires the employment of at least one transparent electrode. Usually, commercially transparent electrodes have been made by deposition of indium tin oxide (ITO) films by RF-Sputtering technique. These commercial electrodes have sheet resistance of about 100 Ω/sq and optical transmittance of 77% at the wavelength of 550 nm. The poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate (PEDOT:PSS) is an alternative material to fabricate transparent electrodes due to its high conductivity (about 600 S/cm) and solubility in water. Soluble conductive materials exhibits advantages for processing of electrode layers, however there is a disadvantage during devices fabrication once materials with the same solvent of the electrode material cannot be coated one over the other. Alternatively, organic/Silica hybrid materials prepared by sol-gel process allow producing bulks and films with high chemical durability. In order to obtain transparent electrodes with high chemical durability, we introduced a blended material comprising the high UV-VIS transparency of organic/Silica sol-gel material and a high conductivity polymer PEDOT:PSS. The organic/Silica sol was obtained using two different molar concentrations (1:1 and 4:1), of tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTS). Amounts of PEDOT:PSS solutions were added to the sol material, resulting in different weight fractions of sol and polymer. G:T/P:P were deposit onto glass substrates by spray-coating. In order to perform electrical characterization of the blended material, gold electrodes were thermally evaporated onto the films. The electrical characterization was performed using a Keithley 2410 source/meter unity and the optical characterization, using a Cary50 UV-Vis spectrophotometer. The absorption coefficient and electric conductivity of the different compositions blends, as function of the PEDOT:PSS concentration, were...

Fabricação e caracterização elétrica de células solares a partir de filmes finos orgânicos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Inclusão das representações de gary e de skilling-umoto em modelos de linhas de transmissão trifásicas: Aplicação em simulações de transitórios eletromagnéticos em sistemas de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Meta-heurísticas para o problema de planejamento de expansão da rede de transmissão de energia elétrica considerando restrições de segurança

Pós-graduação em Engenharia Elétrica - FEIS

Propriedades elétricas de materiais híbridos de Sílica/orgânico à base de GPTS/TEOS preparados pelo método sol-gel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Medidas de condutividade A.C. e constante dielétrica na perovskita dupla Ca1.2 La0.8 FeIrO6

This work introduces the results from the performing of impedance spectroscopy on the transition metals oxide Ca1.2La0.8FeIrO6. It was sought to understand the behavior of one sample from its impedance spectra for different AC voltages and temperature values and if an applied external magnetic field at room temperature would cause some change on it. The results revealed that the Ca1.2La0.8FeIrO6 at high temperatures shows conductive and inductive behavior and that the resistance increases with frequency, phenomenon known as Kelvin effect. At 150 K, the spectrum real part no longer consists with the theoretical prediction of Kelvin effect, starting to be influenced by the utilized voltages, condition that inexists on theory. At low temperatures (10, 20, 30 K) it was observed resistive and capacitive behavior, being possible on these conditions, associate to the sample a paralel RC circuit in series with a contact resistance with a fitting from the ZSim software. This fitting allowed the obtaining of capacitance, DC resistance and contact resistance values. The application of a 700G magnetic field at room temperature didn't cause changes on the spectra

Análise do potencial do sensor OLI (Operational Land Imager) a bordo do Landsat-8 em estimar a concentração de sólidos totais em suspensão no reservatório de Barra Bonita

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Representação de linhas de transmissão trifásicas diretamente no domínio das fases por meio da matriz ABCD

Pós-graduação em Engenharia Elétrica - FEIS

Aplicação da fibra óptica em sistemas FTTX

The evolution in telecommunications with the extensive use of optical fiber following the technological expansion and data transmission demand becomes a necessity today. In this paper a literature review with technical concepts, feasibility of projects and applications in data collection with comparisons and highlights of the current situation of this advance is presented. The benefits of using optical fiber and the advantages of FTTH architecture are identified, as well as concrete and devised projects that make this theme reality and future prospects in the continuity of speed increase and allowed broadcasts growth

Aplicação das normas para adequação de subestação

The first approach in this work is the concept of the electric power transmission and distribution system, as well as the survey of the current condition of substations chosen to thus identify the importance of having a suitable design with respect to security due to the need to obtain the approval for the operation of the substation according to the standards valid in the country. Present the guidelines and present needs when designing improvements, thus ensuring the company for more safety and reliability. From the company's point of view is an opportunity to reduce the cost of maintenance, and the professional point of view is an opportunity that allows a comprehensive study of legal requirements for the operation of substations

Localizador de faltas por ondas viajantes em linhas de transmissão

It is important to ensure smoothly operation of a transmission line, sending energy to the consumption centers with minimal interruptions and safer. With this necessity, the fault location techniques have grown, in order to mitigate the impact of the fault and its correction can be more quickly and accurately. This paper presents a comparison between two different techniques of fault location, the fault location by impedance method, which uses the line parameters, the impedance per distance, voltage and current signals, and the other is the traveling wave method, which uses only a very fast analysis of time, synchronization and length between the line ends, do not using voltage and current values, but the temporal perception of the fault. Using travelling waves fault detection makes the previous knowledge of line parameters obsolete, which helps a lot network technicians and engineers with a quick and easy analysis. The methods are simulated in ATP Draw software, so both algorithms can be evaluated for their effectively and accuracy

Aplicação da fibra óptica em sistemas FTTX

The evolution in telecommunications with the extensive use of optical fiber following the technological expansion and data transmission demand becomes a necessity today. In this paper a literature review with technical concepts, feasibility of projects and applications in data collection with comparisons and highlights of the current situation of this advance is presented. The benefits of using optical fiber and the advantages of FTTH architecture are identified, as well as concrete and devised projects that make this theme reality and future prospects in the continuity of speed increase and allowed broadcasts growth

Aplicação das normas para adequação de subestação

The first approach in this work is the concept of the electric power transmission and distribution system, as well as the survey of the current condition of substations chosen to thus identify the importance of having a suitable design with respect to security due to the need to obtain the approval for the operation of the substation according to the standards valid in the country. Present the guidelines and present needs when designing improvements, thus ensuring the company for more safety and reliability. From the company's point of view is an opportunity to reduce the cost of maintenance, and the professional point of view is an opportunity that allows a comprehensive study of legal requirements for the operation of substations