The propagation of low intensity ultrasound in a curing resin, acting as a high frequency oscillatory excitation, has been recently proposed as an ultrasonic dynamic mechanical analysis (UDMA) for cure monitoring. The technique measures sound velocity and attenuation, which are very sensitive to changes in the viscoelastic characteristics of the curing resin, since the velocity is related to th...

Bulk and Rayleigh (or surface wave) velocities of ultrasonic waves in chromium coatings on steel were measured and an experimental correlation was found between the surface velocity and the hardness. Since qualitative coating evaluation is commonly made using hardnesses as a guideline, the possibility is herewith presented of using the so und velocities of surface ultrasonic waves for this purp...

A technique known as Time Delay Spectrometry (TDS), which has been used at JPL for ultrasonic tissue characterization, has promise for similar application in materials characterization as well. This technique differs from the approaches based on pulse-echo techniques which are used by other workers. Time Delay Spectrometry operates in the frequency domain directly. The transducer is excited by ...

The conventional ultrasonic imaging techniques including the holographic one give a high resolution in angle, but a relatively poor resolution in range, because the resolution in range is obtained only by use of selective focus or parallax useful only with a small focal ratio. This paper presents the principle and some experimental results of new ultrasonic imaging techniques that use a linear ...

Response surface methodology (RSM) based on Box-Behnken design (BBD) was employed to investigate the effect of ultrasonic treatment on beta-carotene production by Blakeslea trispora. The optimized strategy involved exposing three-day-old mycelial cultures to ultrasonic treatment at a fixed frequency of 20 kHz, power of 491 W, treatment time of 3 min, working time of 3 s, and rest time of 5.8 s,...

If it were possible to perform ultrasonic inspections while observing the propagation of ultrasonic waves as dynamic images, the identification of defect echoes would become easier, and inspection, quicker. Furthermore, fewer defects would be overlooked or improperly identified, leading to higher-reliability inspections. For visualizing ultrasonic propagation, we have developed a generation las...

BACKGROUND Ultrasonic dissection devices have been designed for use in open surgery but it is not certain how they compare with standard surgical techniques. METHODS This was a multicentre randomized controlled trial comparing ultrasonic dissection with the traditional surgical technique for haemostasis and dissection during left hemicolectomy and total gastrectomy. The primary endpoint was d...

Ultrasonic testing data is usually visualised in form of Cand D-images. For simple inspection tasks of flat samples, these representation methods are an effective means for identifying and evaluating defects. However, for complex inspection tasks, e.g. testing of large curved composite structures, it is often difficult to relate the findings to the tested structure. Therefore it is important to...