A frequency-swept ultrasonic beam was focused into a biological tissue sample to modulate the laser light passing through the ultrasonic beam inside the tissue. Parallel detection of the speckle field formed by the transmitted laser light was implemented with the source-synchronous-illumination lock-in technique to improve the signal-to-noise ratio. The ultrasound-modulated laser light reflects...

in biological wastewater treatment large quantities of sludge are produced. this sludge is highly putrescible.for disposal and safe usage should be stabilized. the anaerobic digestion is a standard technique for stabilization. due to the rate imiting step of sludge hydrolysis, anaerobic degradation is a slow process with high digestion time. due to high retention time and sludge dewatering prob...

The laser damage precursors in subsurface of fused silica (e.g. photosensitive impurities, scratches and redeposited silica compounds) were mitigated by mineral acid leaching and HF etching with multi-frequency ultrasonic agitation, respectively. The comparison of scratches morphology after static etching and high-frequency ultrasonic agitation etching was devoted in our case. And comparison of...

in this paper, a new non-contact ultrasonic abrasive finishing mechanism is designed and fabricated. this mechanism combines the function of ultrasonic vibrations and the magnetic abrasive finishing (maf) process. a permanent magnet which is mounted on a horn has been used as the processing tool. this polishing tool is vibrated at an ultrasonic frequency with piezo-electric actuators. ultrasoni...

Ultrasonics complex vibrations with twoor three-dimensional vibration locus are effective for various applications. Various high-frequency and complex-vibration systems have been proposed and studied. The applications include ultrasonic direct welding of LSI, semiconductor chips without adhesive or solder, ultrasonic seam welding of thin metal plates, ultrasonic welding of thick metal specimens...

Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have issues pertinent to this frequency range been fully discussed in the literature. An increasing number of...

non-destructive ultrasonic testing is one of the methods utilized to evaluate quality of agricultural produce. transducers used in this method are made for basically industrial applications. since ultrasonic attenuation of waves in agricultural produce is very high, industrial transducers cannot be used in agriculture and needs to be modified. this is done with horns that concentrate energy on ...

Ultrasonic transducers play a significant role in generating and receiving the acoustic waves in ultrasonic flowmeters. Depending on the required accuracy, the ultrasonic transducers can be installed either in one pair or more in an ultrasonic flowmeter. The main part of an ultrasonic transducer is its piezoceramic element. In this work, four piezoceramic elements with different diameter to thi...

INTRODUCTION Automation of ultrasonic testing procedures is a kind of non-destructive testing procedures, which is involves the use of both longitudinal and transverse high-frequency sound waves for the exploration and/or mapping of both surface and sub-surface defect or irregularities. Of course the material thickness or the material loss (corrosions/ erosions) can also be observed by the conc...