The impedance-based structural health monitoring method has become a promising and attractive tool for damage identification is considered nondestructive evaluation technique. However, conventional studies have mainly focused on but not so much statistical modeling approaches in order to determine threshold the decision making of detection system. In this study, technique used problem considering temperature variation effects. For aim, three aluminum 2024-T3 plates were instrumented with...

The electromechanical impedance (EMI) method has been regarded as a promising tool for structural health monitoring (SHM) in real time. Usually, massive, high-cost, single-channel analyzers are used to process the time domain data, aiming at obtaining complex, frequency-dependent, EMI functions, from which features related presence, position, and extent of damage can be extracted. However, large structures, it is desirable deploy an array piezoelectric transducers over area monitored...

Impedance-based structural health monitoring technique is performed by measuring the variation of electromechanical impedance structure caused presence damage. The signals are collected from patches piezoelectric material bonded on surface (or embedded). Through these piezoceramic sensor-actuators, impedance, which directly related to mechanical structure, obtained. Based signals, damage can be detected. A particular metric used quantify Distinguishing groups a universe containing different...

Abstract The impedance-based structural health monitoring technique uses measured signatures changes to identify incipient damages in structures. purpose is perform a correlation of these with the physical phenomena. However, since electromechanical coupling exists, some environmental influences such as temperature may lead false decision regarding condition structure. As result, innovative machine learning tools have been extensively investigated avoid errors prognosis and, this sense,...

6Study developed at Hospital Procardiaco, Rio de Janeiro, RJ, Brazil. 1. Professor Faculdade Medicina Teresopolis, Sub- coordinator for Post-Graduation Institutode Pos-Graduacao Medica Carlos Chagas, Master in Radiology (Magnetic Resonance Imaging Angiography) by Universidade Federal do Janeiro. 2. Coordinatorfor Service of and Diagnostic Procardiaco. 3. Doctor, Adjunct d o 4. MD, Radiologists atService – 5. Cardiologist 6. Professor, Private D ocent Sao Paulo, Advisorfor Mailing Address:...

The electromechanical impedance method has been seen as a promising tool for structural health monitoring regarding different types of structures and purposes. Most importantly, this can be used in real-time applications. Frequently, massive, high-cost, single-channel analyzers are to process the time domain data, aiming at obtaining complex, frequency-dependent functions therefore infer about presence, position extent an existing damage. However, large structures, it is desirable deploy...

Visual examination, ultrasonic tests, and dye penetrant inspection are some examples of nondestructive techniques widely used for crack detection in rotors. These methods have proved to be costly, since satisfactory results rely on detailed periodic inspections. Significant research effort has been directed recent years online monitoring techniques, that is, based vibration signals measured during rotor operation. However, most them able only detect deep cracks. The uniqueness this article...

Energy efficiency is a major concern in wireless sensor networks (WSNs) and as such power control policies play an essential component maximizing network's lifetime. Optimal provide the correct trade-off balancing packet transmission reliability within operational environment with expanded energy based on transceiver characteristics. In this paper, extension of model previously developed for Chipcon CC2420, IEEE802.15.4trade device, presented. The approach provides extended taking into...

This paper proposes a high-power-factor half-bridge doubler boost converter without commutation losses, which provides high output voltages, i.e., from 600 to 900 V. The voltages across the semiconductor devices are low and approximately equal voltage, as doubled reduced high-frequency ripple can be achieved. A detailed mathematical analysis concerning its operation is presented, simulation experimental results describe performance.

A common problem in aircraft maintenance is the development and detection of fatigue cracks structural components with localized high-stress concentration. Traditional non-destructive testing methods are effective inspecting through an offline manner; however, real-time implementation these not common. In this contribution, a procedure to monitor propagating aluminum beams undergoing dynamic cyclic loading presented. High-frequency impedance measurements were performed from lead zirconate...

The essence of structural health monitoring (SHM) is to develop systems based on nondestructive inspection (NDI) technologies for continuous monitoring, and detection damages. A new architecture a remote SHM system Electromechanical Impedance (EMI) measures described in the present contribution. proposed environment employed automatically monitor integrity aircrafts composed by sensor networks, signal conditioning system, data acquisition hardware processing system. obtained results allow...

Malolactic fermentation is a biological deacidification process of wine, characterized by the transformation l‐malic acid to l‐lactic and CO2. Oenococcus oeni able perform malolactic survive under wine harsh conditions, representing great interest for industry. The aim this work was evaluate effect high pressure on metabolism O. growing in culture media, regarding fermentation, sugars bacterial growth. A stress 50 MPa during 8 h did not result significant modifications metabolism. In...

The paper proposes a current controlled inverter operating in zero voltage switching (ZVS) mode for an induction machine drive. Operation with no stress the DC link bus is achieved. Together soft operation, fixed frequency bang-bang control technique also implemented to allow accurate shaping of sinusoidal currents feed motor. As result, ripple free torque profile steady state operation With it possible operate conventional IGBTs at 40 kHz. A detailed analysis circuit presented. feasibility...

Breast cancer is a public health problem and has the highest incidence mortality in female population worldwide. Early detection of breast essential for reducing morbidity associated with this disease. Some methods detecting tumors include ultrasonography, magnetic resonance imaging, positron emission tomography, tomosynthesis, mammography, which are recommended as screening techniques. Each method its advantages disadvantages, such discomfort to patient during examination, possible...

A visão, o sentido predileto do ser humano, e sua grande capacidade de captar, processar interpretar grandes quantidades dados natureza visual tem sido, ao longo dos anos, um estímulo para desenvolvimento técnicas dispositivos tecnológicos que a reproduzam num sistema computacional. Nos processos soldagem, visão pode fornecer na inspeção qualidade da junta soldada, no monitoramento parâmetros, correção trajetórias até, por fim, estudo fenômenos envolvidos processo. Porém, radiação luminosa...