Pulse Echo Technique
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Ultrasound method applied to characterize healthy femoral diaphysis of Wistar rats in vivo
A simple experimental protocol applying a quantitative ultrasound (QUS) pulse-echo technique was used to measure the acoustic parameters of healthy femoral diaphyses of Wistar rats in vivo. Five quantitative parameters [apparent integrated backscatter (AIB), frequency slope of apparent backscatter (FSAB), time slope of apparent backscatter (TSAB), integrated
Braz J Med Biol Res. Publicado em: 04/04/2014
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2. Análise do teor e da qualidade dos lipídeos presentes em sementes de oleaginosas por rmn de baixo campo
To choose among the variety of oleaginous plants for biodiesel production, the oil content of several matrices was determined through different low-field ¹H nuclear magnetic resonance (NMR) experiments with varied pulse sequences, namely single-pulse, spin-echo, CPMG, and CWFP. The experiments that involved the first three sequences showed high correlation
Quím. Nova. Publicado em: 2014
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3. Reconhecimento de PadrÃes AtravÃs de AnÃlises EstatÃsticas e Fractais Aplicadas a Dados de Ensaios NÃo-Destrutivos / Pattern Recognition by Statistical Fluctuation and Fractal Analyses Applied to Nondestructive Testing Data
In this work a procedure is studied for pattern classification related to different types of data, namely: (1) signals obtained from ultrasonic testing ( pulse-echo technique) and magnetic signals obtained from BarkhÃusen noise in samples of ferritic-pearlitic carbon steel tubes which, due to temperature effects, have shown microstructural changes as conseq
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/12/2011
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4. Ultrasonic inspection of AA6013 laser welded joints
Interest in laser beam welding for aerospace applications is continuously growing, mainly for aluminum alloys. The joints quality is usually assessed by non-destructive inspection (NDI). In this work, bead on plate laser welds on 1.6 mm thick AA6013 alloy sheets, using a 2 kW Yb-fiber laser were obtained and inspected by pulse/echo ultrasonic phased-array te
Materials Research. Publicado em: 26/08/2011
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5. Desenvolvimento de tecnicas de ultra-som para medida de espessura de filme de liquido em escoamentos gas-liquido e liquido-liquido / Development of ultrasonic techniques for measurements of liquid film thickness in gas-liquid and liquid-liquid flows
Um dos problemas cruciais no atual cenário da indústria nacional de petróleo é a medição das vazões de óleo, gás e água produzidos por cada poço. Este problema se agrava no contexto da produção de óleos pesados sob condições offshore em águas profundas, dadas as condições adversas desse ambiente, alta viscosidade do óleo, formação de em
Publicado em: 2006
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6. The use of artificial neural network in the classification of pulse-echo and TOFD ultra-sonic signals
The present work evaluates the application of artificial neural networks for pattern recognition of ultrasonic signals using pulse-echo and TOFD (Time of Flight Diffraction) techniques in weld beads. In this study pattern classifiers are implemented by artificial neural network of backpropagation type using MATLAB®. The ultrasonic signals acquired from puls
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2005-12
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7. AplicaÃÃo dos mÃtodos de pulso-eco e resonÃncia acÃstica para caracterizaÃÃo nÃo destrutiva de propriedades elÃsticas e microestruturais de vidros especiais e aÃo ferrÃtico degradado por fluÃncia
The elastic properties, homogeneity, attenuation of the propagation of ultrasonic waves and associated structure with some types of special glass were analyzed with the pulse-echo method. A total of seven samples of glass containing neodymium, lead, zirconium and niobium, as additives were analyzed. As a result, elastic constants such as coefficient of Poiss
Publicado em: 2005
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8. DifusÃo e transporte na presenÃa de macromolÃculas. Imagens e espectroscopia por RMN
The electronic Overhauser effect was employed to enhance nuclear magnetic resonance images obtained in a magnetic eld of only 16 mT. Despite the weak magnetic eld, the technique can reveal, in some systems, various aspects of ionic transport and kinetics apparently not observed in conventional high-eld magnetic resonance imaging. We employed Overhauser imagi
Publicado em: 2004
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9. Deuterium nuclear magnetic resonance investigation of the effects of proteins and polypeptides on hydrocarbon chain order in model membrane systems
Deuterium Fourier-transform nuclear magnetic resonance spectra have been obtained of 1-myristoyl 2-(14,14,14-trideutero)myristoyl phosphatidylcholine bilayers at 34.1 MHz by using the quadrupole echo pulse technique. Thereby, we have investigated the effects upon the deuterated dimyristoyl phosphatidylcholine bilayers of the following proteins and polypeptid
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10. Protein dynamics and the immunological evolution of molecular recognition
While it is accepted that protein flexibility plays a role in protein folding, catalysis, and molecular recognition, few techniques are capable of the rigorous measurement of protein motions required to quantify flexibility. Three-pulse photon echo shift spectroscopy can be used to measure the time scale of protein motions, and we have used this technique, a
National Academy of Sciences.