In this study, superconducting electromagnetic acoustic transducer (EMAT) is developed to transmit strong ultrasound, which is expected as an experimental tool for mechanism study of nonlinear ultrasound. For the purpose, EMAT experiment is carried out using uniform and strong filed generated by a superconducting magnet, and surface displacement of specimen is measured by a laser Doppler vibrometer. As the result, the linear relationship between the surface displacement and magnetic flux density was co...
英字タイトル:
Development of superconducting electromagnetic acoustic transducer system and quantitative evaluation of ultrasound transmission by numerical analysis

Electromagnetic acoustic transducer (EMAT) provides non-contacting measurements and is often applied to monitoring in high temperature environment. Electromagnetic acoustic resonance method (EMAR) is transmits an ultrasonic burst wave, and the driving frequency of bust wave is swept. Then signal amplitude of each frequency is computed by the superheterodyne processing at the interval. Pulse-EMAR method is transmits an ultrasonic pulse wave propagating, but the pulse wave is not swept. Then echo waves recei...
英字タイトル:
Influence of bottom shape in the pipe wall thinning inspection using an electromagnetic acoustic resonance method

The degradation of 1-nozzle type Jet Pump (JP) efficiency by crud deposition has been recognized in some BWRs. In order to remove crud, we must clean each o r all of JP inner surface. The increase in cleaning surface area induces the increase in outage period and cost, therefore, in the previous study we looked for the most effective cleaning portion at inner surface for efficiency recovery. In this study, for the 5-nozzle type JP, we evaluated the effect of crud portion on decrease in efficiency of 5-noz...
英字タイトル:
Studies on Recovering Method of 5-nozzle type Jet Pump Efficiency