Wave frequency, ultrasound parameter

The parameters that best characterize an ultrasonic field are the wave frequency and the ultrasonic energy applied, with the latter being expressed as power, intensity, or acoustic pressure. The frequency does not represent a critical point because the variation of the applied frequency is usually less than 5-10% of the nominal frequency provided by the manufacturer. In contrast, the actual applied acoustic energy could be very different from the electrical consumption, and its direct measurement is difficult. In the literature, it is possible to identify a wide variety of methods for that purpose, but the results provided may be difficult to compare one with another. The majority of these methods are based on the measurement of physical or chemical changes produced by ultrasound, and a classification was proposed by Berlan and Mason (1996) ... 

We are now in a position to discuss the effects of low frequency (< 400 kHz) high intensity (> 3 W cm ) ultrasonic waves on macromolecules (polymers) and examine how the parameters such as frequency, intensity, hydrostatic pressure etc affect both the polymerisation and also the depolymerisation processes. We will also consider in this chapter the use of ultrasound in polymer processing. 

Ultrasound is used to obtain information about the properties of a material by measuring the interaction between a high frequency sound wave and the material through which it propagates. This interaction depends on the frequency and nature of the ultrasonic wave, as well as the composition and microstructure of the material. The parameters most commonly measured in an ultrasonic experiment are the velocity at which the wave travels and the extent by which it is attenuated. To understand how these parameters are related to the properties of foods it is useful to consider the propagation of ultrasonic waves in materials in general. 

Ultrasound is a sound wave possessing frequencies above 20 kHz. These waves are characterized by two main parameters frequency and amplitude. 

Abstract Contribution of the Jahn-Teller system to the elastic moduli and ultrasonic wave attenuation of the diluted crystals is discussed in the frames of phenomenological approach and on the basis of quantum-mechanical theory. Both, resonant and relaxation processes are considered. The procedure of distinguishing the nature of the anomalies (either resonant or relaxation) in the elastic moduli and attenuation of ultrasound as well as generalized method for reconstruction of the relaxation time temperature dependence are described in detail. Particular attention is paid to the physical parameters of the Jahn-Teller complex that could be determined using the ultrasonic technique, namely, the potential barrier, the type of the vibronic modes and their frequency, the tunnelling splitting, the deformation potential and the energy of inevitable strain. The experimental results obtained in some zinc-blende crystals doped with 3d ions are presented. 

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