Comparative analysis for reactive energy measurement methodologies, under non-sinusoidal conditions in three-phase four-wire circuits

This paper presents some methodologies for reactive energy measurement, considering three modern power theories that are suitable for three-phase four-wire non-sinusoidal and unbalanced circuits. The theories were applied in some profiles collected in electrical distribution systems which have real characteristics for voltages and currents measured by commercial reactive energy meters. The experimental results are presented in order to analyze the accuracy of the methodologies, considering the standard IEEE 1459-2010 as a reference. Finally, for additional comparisons, the theories will be confronted with the modern Yokogawa WT3000 energy meter and three samples of a commercial energy meter through an experimental setup. © 2011 IEEE.

Nonlinear dynamics of a flexible portal frame under support excitation

This paper presents a nonlinear dynamic analysis of a flexible portal frame subjected to support excitation, which is provided by an electro-dynamical shaker. The problem is reduced to a mathematical model of four degrees of freedom and the equations of motion are derived via Lagrangian formulation. The main goal of this study is to investigate the dynamic interactions between a flexible portal frame and a non-ideal support excitation. The numerical analysis shows a complex behavior of the system, which can be observed by phase spaces, Poincaŕ sections and bifurcation diagrams. © 2012 American Institute of Physics.

Eigenvalue analyses for non-transposed three-phase transmission line considering non-implicit ground wires

This paper presents a method for analyzing electromagnetic transients using real transformation matrices in three-phase systems considering the presence of ground wires. So, for the Z and Y matrices that represent the transmission line, the characteristics of ground wires are not implied in the values related to the phases. A first approach uses a real transformation matrix for the entire frequency range considered in this case. This transformation matrix is an approximation to the exact transformation matrix. For those elements related to the phases of the considered system, the transformation matrix is composed of the elements of Clarke's matrix. In part related to the ground wires, the elements of the transformation matrix must establish a relationship with the elements of the phases considering the establishment of a single homopolar reference in the mode domain. In the case of three-phase lines with the presence of two ground wires, it is unable to get the full diagonalization of the matrices Z and Y in the mode domain. This leads to the second proposal for the composition of real transformation matrix: obtain such transformation matrix from the multiplication of two real and constant matrices. In this case, the inclusion of a second matrix had the objective to minimize errors from the first proposal for the composition of the transformation matrix mentioned. © 2012 IEEE.

Decoupled reference generator for shunt active filters using the conservative power theory

Based on the framework of the Conservative Power Theory (CPT), this paper proposes some compensation strategies for shunt current compensators. CPT current decompositions result in several current-related terms associated with specific load characteristics, such as power consumption, energy storage, unbalances and load nonlinearities. These current components are decoupled (orthogonal) from each other and are used here to define different compensation strategies, which can be selective in minimizing particular effects of disturbing loads. Compensation strategies for single- and three-phase four-wire circuits are also considered. Simulated and experimental results are described to validate the possibilities and performance of the proposed strategies. © 2013 Brazilian Society for Automatics - SBA.

Acute phase protein profile in agoutis (Dasyprocta azarae; Lichtenstein, 1823) in captivity, determined by sodium dodecyl sulfate polyacrilamyde gel electrophoresis

The acute phase response refers to a nonspecific and complex systemic reaction of the organism that occurs shortly after any tissue injury. The acute phase response is considered a part of the innate host defense system, which is responsible for the survival of the host during the critical early stages of attack, and in evolutionary terms, it precedes the acquired immune response. The purpose of this study was to determine serum protein concentrations, including the acute phase protein profile in agoutis (Dasyprocta azarae) in captivity, by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Blood samples from 11 adult healthy animals (nine females and two males) were obtained. The serum proteinogram had 21 proteins with molecular weights ranging from 15 to 240 kD. The acute phase proteins identified were: ceruloplasmin, transferrin, albumin, haptoglobin, α-1-acid glycoprotein, and hemoglobin. IgA, IgG heavy and light chains, and nonnominal identified proteins of 240, 210, 140, 98, 78, 48, 35, 31, 23, and 15 kD were also identified. The determination of the acute phase protein concentrations is a useful method for the early detection of subclinical disease or changes in the healthy animal, with predictive information on the development of disease in the future. It is possible to standardize the reference values of the serum protein profile of agoutis, which can be used for diagnosis and prognosis, treatment and clinical follow-up of nutritional disorders, and immune-mediated inflammatory diseases that may affect these animals. © 2012 Springer-Verlag London Limited.

Interferometria óptica aplicada à medição de amplitudes de vibração nanométricas em piezoatuadores flextensionais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento e implementação de um sintetizador de frequência CMOS utilizando sistema digital

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Some comments on the nonlinear dynamics of a portal frame under base excitation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Writing saturated holograms in LiNbO3 crystals through phase control and double diffraction

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

Lead-free BaBi4Ti4O15 ceramics: Effect of synthesis methods on phase formation and electrical properties

The processing of ferroelectric BaBi4Ti4O15 (BBT) ceramics from powders prepared by conventional solid state reaction (SSR) and mechanochemical activation (MA) has been investigated. It was shown that MA synthesis reduces the synthesis temperature of BBT powders, leading to smaller particles with reduced anisotropy and consequently to smaller grain size of ceramics. Dielectric properties were investigated in a wide range of temperatures (20-800 degrees C) and frequencies (1.21 kHz to 1 MHz). The relative dielectric permittivity at Curie temperature was higher for solid state obtained ceramics than for the mechanically treated ones. The conductivity of sintered samples was studied, suggesting decreasing of conductivity of BBT-MA in comparison with BBT-SS ceramics. The influence of the grain and the grain boundaries contribution to the dielectric behavior in both ceramics was analyzed through impedance spectroscopy. A well-defined ferroelectric hysteresis loop was obtained for both samples. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Projeto de controladores robustos para acionamento de um motor de indução trifásico

Pós-graduação em Engenharia Elétrica - FEIS