The Mapping of Ultrasound Fields Topology

Several methods are used for the determination of the active zones in a vessel. These include optical (light diffraction), chemical, electrical, or mechanical (metal foil perforation), the measurement of local temperature increase (silicone-coated thermocouple), microdiffusion sensor, microvibration thermal sensor, microphones, or sonoluminescence.45 The principle of the latter consists of the oxidative degradation of luminol to aminophthalate under the action of the hydroxyl radical produced by water sonolysis. Aminophthalate is produced in an 

43 Suslick, K.S. Schubert, P.F. Goodale, J.W. IEEE Ultrasonics Symp. 1981, 612-616. 

A second example of luminescence mapping was effected in a flat-bottomed Inox cuvette filled with a luminol solution, with four transducers at its base (nominal frequency v = 25 kHz). Exposure times as long as 15 min are necessary, but the light emitted can be seen in the dark with the naked eye. 

47 Trabelsi, F. Ait-Lyazidi, H. Berlan, Fabre, P.L. Delmas, H. Wilhem, A.M. Ultrasonics Sonochemistry 1996, 3, S125-S130. 

A comparative study was published on the mapping of energy in a low-frequency and the equivalent high-frequency reactor (Fig. 13). The method used here is also chemiluminescence of luminol. 

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