Ultrasonic Wave Velocity
Mostrando 13-21 de 21 artigos, teses e dissertações.
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13. Ultrasonic study of structural instabilities in nickel induced by magnetic fields
The ultrasonic phase velocity was measured on a high purity nickel single crystal with a bias magnetic field in cooling and heating runs over the interval of temperatures from approximately 100 to 325 K. An evident anomaly of the phase velocity was observed in both branches of the temperature cycle. The temperature of the anomaly in the heating run was alway
Materials Research. Publicado em: 2008-03
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14. Influence of the specimen size on destructive methods of parallel compression grain and on the test non-destructive using ultra sonic waves / Influencia da dimensão do corpo-de-prova no ensaio destrutuvo de compressão paralela as fibras e no ensaio não-destrutivo utilizando ultra-som
é praticamente toda exportada em sua forma in natura sem que a ela seja agregado valor de beneficiamento. Um dos problemas enfrentados pela indústria moveleira é o fato da madeira não ser submetida à classificação, dificultando a elaboração de projetos e a certificação da qualidade do móvel confeccionado a partir deste material. Nesse contexto as
Publicado em: 2006
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15. Moisture content effect on ultrasonic velocity in Goupia glabra
This paper discusses the application of ultrasound waves on a Brazilian hardwood, Goupia glabra, to evaluate the sensitivity of the ultrasonic technique to the moisture content in wood. The velocity of ultrasonic wave is sensitive to the material's quality-determining factors; hence, this technique is an important industrial tool to improve the quality contr
Materials Research. Publicado em: 2005-03
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16. Variations in ultrasonic wave velocity with moisture content / Velocidade de propagação de ondas de ultra-som na madeira para diferentes condições de umidade
A madeira, sendo um material higroscópico, tem suas propriedades mecânicas e elásticas afetadas por condições ambientais. Sendo assim, a relação de dependência de propriedades da madeira com a variação do teor de umidade tem merecido, há muito tempo, a atenção de pesquisadores de todo o mundo. Um dos grandes avanços obtidos nos últimos anos na
Publicado em: 2005
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17. Anemometer Based on the Method of Time of Transit: Comparative study of architectures, evaluation of uncertainties and implementation. / Anemômetro Baseado no Método de Tempo de Trânsito: Estudo comparativo de arquiteturas, avaliação de incertezas e implementação.
Anemometers are instruments, simply, for measuring the velocity of fluids and, in some cases, its direction. Particularly, the measurement of the air velocity extends to applications like: windmills, wind tunnels, electricity generation from Aeolian energy and meteorology. Among the most used methods for the wind velocity determination, the method based on t
Publicado em: 2004
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18. Assessment of bony tissue by ultrasound for osteoporosis diagnosis. / Caracterização de tecido ósseo por ultra-som para o diagnóstico de osteoporose.
Ultrasonic assessment of bone for managing osteoporosis has been investigated as an alternative to radition-based bone densitometry technology. In contrast with the ionizing electromagnetic radiation of such clinical bone densitometric technique, ultrasound is a mechanical wave and thus interacts with bone in a fundamentally distinct manner. Ultrasound is vi
Publicado em: 1996
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19. Diagnosis and evaluation of mitral valve disease using transseptal Doppler ultrasound catheterization.
In 33 patients with confirmed mitral valve disease, the mitral valve flow velocity traces were recorded by means of a directional Doppler ultrasonic velocimeter using the transseptal route, and correlated with the clinical and haemodynamic data. In all cases, characteristic anomalies of the mitral flow velocity patterns were noted and could be related to the
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20. Fractal ladder models and power law wave equations
The ultrasonic attenuation coefficient in mammalian tissue is approximated by a frequency-dependent power law for frequencies less than 100 MHz. To describe this power law behavior in soft tissue, a hierarchical fractal network model is proposed. The viscoelastic and self-similar properties of tissue are captured by a constitutive equation based on a lumped
Acoustical Society of America.
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21. Continuous-wave versus range-gated pulsed Doppler power frequency spectrum analysis in the detection of carotid arterial occlusive disease.
Two types of ultrasonic Doppler velocity metering devices currently used in the detection of extracranial carotid artery disease, the continuous-wave (CW) and the range-gated pulsed (RP) Doppler systems, were compared in the present study. Power frequency spectrum analysis (PFSA) was performed on 130 carotid arterial bifurcations with a CW Doppler and 81 car