Effects and Mechanisms

Acoustic Cavitation at the Water−Glass Interface

“…According to the literature, ultrasound-assisted erosion of surfaces is generally attributed to two principal effects: microjets and shock-waves. 2,[12][13][14]16,47 However, our results show that microjet impingements do not appear as a valuable factor explaining the erosion of glass surfaces. Indeed, microjets are inrushes of liquid that hit the surface with a velocity estimated to be about several hundred meters per second.…”

“…In addition, the collapse of the surrounding bubbles leads to the emission of shock waves supposed to reach a pressure of several GPa with a starting shock velocity of ∼4000 m s -1 . [10][11][12][13][14] These particular events, generally responsible for the occurrence of microdamages on sonicated surfaces, go with other effects (e.g., microstreamings and microturbulences) that will act together at the interface in different ways such as erosion, fusion, fragmentation, inclusion, etc. 1,5,[15][16][17][18] Among these broad effects, ultrasound-assisted cavitation erosion is a topic that attracted the attention of many scientists in view of the development of useful applications (cleaning, soldering, dentistry, extraction...).…”

Activating Drugs with Sound: Mechanisms Behind Sonodynamic Therapy and the Role of Nanomedicine

“…Sonoluminescence, first observed in 1934 by Frenzel et al, describes the phenomenon through which the energy released from the rapid collapse of a bubble during acoustic cavitation instigates a very brief emission of light. While generally associated with inertial cavitation due to the rapid release of energy resulting from bubble implosion, two studies have reportedly observed sonoluminescence at acoustic pressures and amplitudes attributed to stable cavitation. , Given the lack of extreme energy output in stable cavitation, theoretical models have suggested that the gaseous phase within the bubble can attain T max similar to inertial cavitation to generate photons and thereby sonoluminescence via stable cavitation . Although minimal study has gone into analyzing the possibilities of such an event, the generation of sonoluminescence under conditions of stable cavitation would promisingly allow for more control over sonosensitizer activation and greater ultrasound/sonosensitizer synergy in the absence of confounding effects from inertial cavitation.…”

Sonocrystallization of Fats

“…In addition, the detection of events created from bubble excitation during sonication can be quantified using cavitation erosion and sonochemistry techniques, while acoustic techniques (low intensity, high frequency ultrasound) can be used to detect both oscillating (or excited) and non-oscillating bubbles. Acoustic techniques have the advantage that they can be used with opaque materials and that they can be used to detect bubbles that oscillate at small amplitudes (Leighton 1994). Martini et al (2012) has recently studied the formation and life cycle of bubbles generated during sonication in an edible lipid (soybean oil) using low intensity ultrasound.…”