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 transmission tomography is one of the measurement methods used for imaging of internal structure of various media. The method can be used in gaseous media, e.g. to identify the shape, size and location of objects, to determine the spatial distribution of temperature in a studied area (if here is a heterogeneous field of that quantity) and to determine concentration of components of s...

An experimental study was carried out to investigate the effect of local ultrasonic forcing on a turbulent boundary layer. The ultrasonic forcing system was constructed by adhering six ultrasonic transducers to a flat plate over which water was flowed. In this system, the ultrasonic waves projected into the water by the transducers caused cavitation, giving rise to an enormous number of tiny ai...

̶ The use of airborne ultrasonic transducers for wireless communication was demonstrated. The work used capacitive ultrasonic transducers to transmit coded binary signals through parallel air channels. On-Off Keying modulation was successfully implemented in the system. Within the limited bandwidth of the transducers, six channels were used at frequencies from 50 kHz to 110 kHz with a channel sp...

Significant improvement in the performance of capacitive microfabricated ultrasonic transducers is reported and the modifications which enable the progress are described. Air-coupled through-transmission of glass and steel at 2.3 MHz is demonstrated for the first time. Furthermore, a 20 pm step on a silicon wafer is detected with both amplitude and phase signals at 3 MHz. The same process used ...

Abstract In response to the continuous demand for industry progress and need low-cost alternative materials that have superior properties than present ones, a new coupling agent was used treat composites, which were as backing in ultrasonic array transducers. transducers, back-echo reverberation piezoelectric elements occurs, so are critical reducing these echoes. The Cu–Al–Zn-alloy treated wit...

This chapter is dedicated to ultrasonic piezoelectric ceramic power transducers. These elements are now the most popular source of high power ultrasound and is used in many industrial applications. High power ultrasonic waves are generally used in such industrial processes as welding, acceleration of chemical reactions, scavenging in gas medium, echo sounding and underwater communication (sonar...

Capacitive micromachined ultrasonic transducers ~CMUTs!, introduced about a decade ago, have been shown to be a good alternative to conventional piezoelectric transducers in various aspects, such as sensitivity, transduction efficiency, and bandwidth. In this paper, we discuss the principles of capacitive transducer operation that underlie these aspects. Many of the key features of capacitive u...