Applications of Ultrasound-Based Detection Techniques

Because ultrasound (US) can penetrate optically opaque materials, provides high-quality information about bulk properties at low cost in a rapid, non-invasive manner, and enables on-line measurements, detection techniques based on this form of energy have something to offer scientists and engineers at large and warrants consideration by anyone concerned with automated analyses and measurements. 

Ultrasound-based deteotion techniques and their ensuing methods are being increasingly developed outside the traditional physical and electronic engineering environments of the earliest implementation. A wide range of disciplines currently use these techniques and have helped develop them further. Because each discipline has developed US-detection techniques as tools to an end rather than as ends in themselves, developments often have not been oommunioated beyond a small circle. 

Clarifying some oonoepts of US-based detection techniques may help increase the appeal of the applioations discussed below. Thus, these techniques require no cavitation as the power levels of US-based instruments are up to millions of times iowerthan those of US baths and probes. For example, US velocity measurements are usuaiiy made at very low power levels, so the analysed material is normally left intact. In addition, the use of low US power levels (e.g. below ca. 10 kW/m in water at room temperature) results in elastic displacements ( .e. strain and stress are linearly related). 

For some reason, there is the widespread belief that US velocity, on which many measurements are based, depends mainly on the density of the material through which US propagates. One connected misconception is that US velocity in a mixture of materials will be some average of the velocities of the mixture components. 

Some types of measurements are given different names (e.g. pulse-echo measurements are also known as pitch and catch , pulse-echo time of flight or acoustic time of flight measurements). 

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Medical applications of ultrasound-based detection techniques... 

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