Steel bars identification in reinforced concrete structures by using ANN and magnetic fields

This work proposes a methodology for non destructive testing (NDT) of reinforced concrete structures, using superficial magnetic fields and artificial neural networks, in order to identify the size and position of steel bars, embedded into the concrete. For the purposes of this paper, magnetic induction curves were obtained by using a finite element program. Perceptron Multilayered (PML) ANNs, with Levemberg-Marquardt training algorithm were used. The results presented very good agreement with the expect ones, encouraging the development of real systems based upon the proposed methodology.

Modelo estocástico de programação matemática de alocação de medidores de tensão em alimentadores radiais de distribuição de energia elétrica para localização de faltas e monitoramento do perfil de tensão

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de um sistema de medição de baixo custo para a monitoração de alimentadores aéreos de distribuição de energia elétrica da classe 15 KV

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização de modelos de falhas e observadores de estado em estruturas reticuladas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Proposta de Algoritmos Inteligentes para Localizar Faltas e Monitorar a Qualidade da Energia em Redes de Distribuição de Energia Elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Localização de faltas em alimentadores de distribuição de energia elétrica usando medições esparsas de tensões

Pós-graduação em Engenharia Elétrica - FEIS

Desenvolvimento de um sistema de proteção e metodologia para localização de faltas em sistemas de distribuição

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Proposta de um algoritmo eficiente para a localização de faltas por relé diferencial numérico para proteção de linhas de transmissão com compensação série controlada por tiristores (TCSC)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

Structural FRF acquisition via electric impedance measurement applied to damage location

Continuing development of new materials makes systems lighter and stronger permitting more complex systems to provide more functionality and flexibility that demands a more effective evaluation of their structural health. Smart material technology has become an area of increasing interest in this field. The combination of smart materials and artificial neural networks can be used as an excellent tool for pattern recognition, turning their application adequate for monitoring and fault classification of equipment and structures. In order to identify the fault, the neural network must be trained using a set of solutions to its corresponding forward Variational problem. After the training process, the net can successfully solve the inverse variational problem in the context of monitoring and fault detection because of their pattern recognition and interpolation capabilities. The use of structural frequency response function is a fundamental portion of structural dynamic analysis, and it can be extracted from measured electric impedance through the electromechanical interaction of a piezoceramic and a structure. In this paper we use the FRF obtained by a mathematical model (FEM) in order to generate the training data for the neural networks, and the identification of damage can be done by measuring electric impedance, since suitable data normalization correlates FRF and electrical impedance.

Design of a state observer using decay rate LMI constraints for fault detection in mechanical systems

Nowadays, one of the most important concerns for many companies is to maintain the operation of their systems without sudden equipment break down. Because of this, new techniques for fault detection and location in mechanical systems subject to dynamic loads have been developed. This paper studies of the influence of the decay rate in the design of state observers using LMI for fault detection in mechanical systems. This influence is analyzed by the performance index proposed by Huh and Stein for the condition of a state observer. An example is presented to illustrate the methodology discussed.

Preferential location of prilocaine and etidocaine in phospholipid bilayers: A molecular dynamics study

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

Preferential location of lidocaine and etidocaine in lecithin bilayers as determined by EPR, fluorescence and H-2 NMR

We have examined the effect of the uncharged species of lidocaine (LDC) and etidocaine (EDC) on the acyl chain moiety of egg phosphatidylcholine liposomes. Changes in membrane organization caused by both anesthetics were detected through the use of EPR spin labels (5, 7 and 12 doxyl stearic acid methyl ester) or fluorescence probes (4, 6, 10, 16 pyrene-fatty acids). The disturbance caused by the LA was greater when the probes were inserted in more external positions of the acyl chain and decreased towards the hydrophobic core of the membrane. The results indicate a preferential insertion of LDC at the polar interface of the bilayer and in the first half of the acyl chain, for EDC. Additionally, 2 H NMR spectra of multilamellar liposomes composed by acyl chain-perdeutero DMPC and EPC (1:4 mol%) allowed the determination of the segmental order (S-mol) and dynamics (T-1) of the acyl chain region. In accordance to the fluorescence and EPR results, changes in molecular orientation and dynamics are more prominent if the LA preferential location is more superficial, as for LDC while EDC seems to organize the acyl chain region between carbons 2-8, which is indicative of its positioning. We propose that the preferential location of LDC and EDC inside the bilayers creates a "transient site", which is related to the anesthetic potency since it could modulate the access of these molecules to their binding site(s) in the voltage-gated sodium channel. (C) 2007 Elsevier B.V. All rights reserved.

Effects of the season of the year, truck type and location on truck on skin bruises and meat quality in pigs

The purpose of this study was to evaluate the effect of the season of the year (summer vs winter), type of truck (A: single decker vs B : double-decker) and pig location on the truck (front, middle, rear) on the incidence of skin bruising and pork quality variation. For this purpose, 2660 gilts of an average weight of 126.7 (+/- 6.6) kg originating from 19 different farms were used. No interaction between season of the year, type of truck and location on truck was observed. A higher number of bruises on the body at unloading and slaughter (P < 0.0001) and a higher number of bruises on the carcass (P < 0.01) were observed in winter. At unloading a higher number of bruises on the body and on the carcass after slaughter was observed in pigs transported on Truck A (P=0.004 and P=0.05). A higher, although not significant, number of bruises was found on the body of pigs transported in the rear compartment of both trucks. Higher paleness value was found in the longissimus and semimembranosus muscles in summer (P=0.0001) than in winter. Cold and heat stress have a negative influence on skin bruises and meat quality, respectively. Poor vehicle design increases the incidence of bruised carcasses without detracting from pork quality regardless of the climate conditions tested and location of the animal it] the truck. (c) 2006 Elsevier B.V. All rights reserved.