continuous exposure to high-energy ultrasonic waves depolymerises macromolecules in solutions and produces a permanent reduction in viscosity. different factors affect the efficiency of this ultrasonic depolymerisation. in this work ultrasonic degradation of one commercially important hydrogel based on acrylic acid and acrylamide was carried out in aqueous solution at room temperature (25oc). a...

In order to obtain the high-performance composites with high density, the influence of additional ultrasonic vibration on the infiltration of molten aluminum alloy (ASTM A336.0) into nickel porous preform by low-pressure and pressureless casting was investigated. There was no effect of ultrasonic vibration on infiltration distance under pressureless casting because of presence of surface oxide ...

The effect of low power ultrasonic radiation on anaerobic biodegradability of sewage sludge was investigated. For this purpose, soluble substances and variation of microbial system of sewage sludge subjected to low power ultrasonic radiation were tested. The well known hydromechanical shear forces and heating effect of low frequency ultrasound plays a major role in the sludge pre treatment proc...

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...

An ultrasonic vibration has been superposed on the normal electrode movement to increase the flushing effect during a micro electro-discharge machining (EDM) process. A systematic study on the effects of ultrasonic vibration on the EDM performance for fabricating microholes in Nitinol has been completed. The introduction of ultrasonic vibration to the microEDM process has more than 60 times inc...

An experimental setup is designed to detect composite delamination damage based on ultrasonic infrared thermography. The ultrasonic infrared thermography system is composed by ultrasonic excitation system, infrared thermal imager and data acquisition system and two damaged composite plate specimens are produced in the experiment. The image processing methods including thresholding, filters, edg...

The earlier report that the frequency dependence of ultrasonic absorption of mammalian testis memicked a single relaxation process is explained as an effect of ultrasonic beam width upon the transient thermoelectric technique. More detailed measurements show that the frequency dependence of the ultrasonic absorption in testis is much the same as the attenuation in other soft tissues, viz., a pr...

In ultrasonic welding, high frequency vibrations are combined with pressure to join two materials together quickly and securely. Ultrasonic welding can join dissimilar metals in a split second, ultrasonic welding eases problematic assembly and this cost effective technique may be key to mass producing fuel efficient. In this work effect of various parameters on weld strength have been studied. ...

Using numerical simulations, we investigated the responses of the π-phase-shifted fiber Bragg gratings (πFBGs) impinged by pressure ultrasonic waves. The effect of the grating length, grating refractive index modification depth, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the πFBG ultrasonic sensor for ultrasonic waves of different wavelengths was analyze...