No abstract

Diante da crescente evolução tecnológica, distúrbios das mais diversas classes e ordens acometem os sistemas de distribuição de energia elétrica. Dentre todos os distúrbios o que mais se destaca são as distorções harmônicas, devido à crescente inserção de cargas não lineares que se agregam aos sistemas elétricos de potência. Por sua vez, esses distúrbios provocam alterações na forma de onda fundamental das correntes e tensões ocasionando enormes prejuízos financeiros. Neste cenário, o ideal seria monitorar as tensões harmônicas em cada ponto do sistema por meio de medidores de qualidade da energia elétrica, contudo este procedimento ainda é inviável financeiramente. Assim, a proposta deste trabalho é analisar o desempenho de um estimador de estado harmônico que leve em consideração situações reais de monitoramento e que seja capaz de estimar os valores de tensão em todas as barras de sistemas de distribuição e, portanto, as distorções harmônicas presentes em todo um sistema teste de 34 barras do IEEE.

No abstract

Due to its high economic impact, when a new technology is handed over from manufacturer to customer, the contractually fixed guarantees and specifications have to be proven. Besides guarantees concerning environmental tasks, such as flue gas emissions, the availability and performance data of the new technology are the key issue. Field performance usually lacks very accurate measuring equipments and stable measurement conditions, as in many manufacturer testing laboratories. In this work a methodology was developed to evaluate performance and emissions under field conditions, together with a critical analysis of the resulting uncertainty of the main parameters, which are representative of the system performance, which was also detailed. In order to overcome field measurement difficulties, a methodology was used to measure combustion air flow rate from emission and gas flow rate measurements. The evaluation procedure was demonstrated by testing a microturbine based cogeneration system, which comprises a microturbine, a heat recovery system, and a steel storage hot water tank, providing electrical energy to Pontifical Catholic University of Rio de Janeiro grid and thermal energy for heating domestic water in cogeneration to its gymnasium showers. Data were acquired at carefully chosen stable test periods in which the gas microturbine was setup to produce electrical energy at nominal power outputs of 100, 75, 50 and 25% of maximum load. In addition, this paper presents an economical analysis for the system, which operates during peak hours (17:30 to 20:30) from Monday to Friday.

In this paper, we introduce simple procedures not only to enhance the polarized photoluminescence (PL) of poly(9,9-di-noctylfluorenyl-2,7-diyl) (PFO) films but also to vary the relative concentrations of PFO αand β-phases. Enhanced molecular ordering was obtained by creating surface grooves on quartz substrates onto which PFO films were deposited and treated at temperatures within the PFO nematic phase. More specifically, the molecular order parameter increased from ca. 0.10 for films on quartz substrates to 0.57 when PFO was deposited on grooves generated by sliding a heated polytetrafluoroethylene (PTFE) bar on the substrate, and the films were treated at 180, 230, and 250 °C. Furthermore, higher ordering was reached with PFO adsorbed via self-assembly than by dip coating. Upon combining polarized absorption, PL, and emission ellipsometry, we could confirm the macroscopic alignment and the change from αto β-phase in PFO films. The approach presented here serves to control polarized emission, which is relevant for applications such as optical displays, flat panels, optical storage, and optoelectronic devices, and to identify the structural properties of photoluminescent polymers.