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The effect that surface-active solutes, such as aliphatic alcohols and sodium dodecyl sulfate (SDS), have on the extent of bubble coalescence in liquids under different sonication conditions has been investigated by measuring the volume change of the solution following a period of sonication. In general, the adsorption of surface-active solutes onto the(More)
A solution of gold chloride was reduced using ultrasound irradiation to prepare metallic gold nanoparticles under conditions of microgravity and normal gravity at sea level. Particle size distributions were measured using TEM analysis. A mean particle diameter of 10 nm was obtained in microgravity while a mean diameter of 80 nm was obtained in the(More)
A simple method is described for determining the size of sonoluminescence bubbles generated by acoustic cavitation. The change in the intensity of sonoluminescence, from 4 ms pulses of 515 kHz ultrasound, as a function of the "off" time between acoustic pulses, is the basis of the method. The bubble size determined in water was in the range of 2.8-3.7 mum.
The emission from electronically excited sodium atoms (Na*) from aqueous solutions containing NaCl or sodium dodecylsulfate under ultrasonic irradiation is studied. Evidence is presented that strongly suggests Na* emission arises from a population of bubbles that are sonochemically active but not producing sonoluminescence (SL). Results indicate that the(More)
Acoustic cavitation is the fundamental process responsible for the initiation of most of the sonochemical reactions in liquids. Acoustic cavitation originates from the interaction between sound waves and bubbles. In an acoustic field, bubbles can undergo growth by rectified diffusion, bubble-bubble coalescence, bubble dissolution or bubble collapse leading(More)
High-intensity ultrasound induces emulsification and cross-linking of protein molecules in aqueous medium. The stability and the functionality of the resultant protein-coated microbubbles are crucial in many of their applications. For example, the stability of drug-loaded microbubbles should be sufficiently long enough, in vivo, so that they can be ruptured(More)
The effect of 20 kHz ultrasound on the viability of Cryptosporidium oocysts was investigated. More than 90% of the dispersed Cryptosporidium oocysts could be deactivated in about 1.5 min of continuous sonication. In order to apply this technique to large quantities of contaminated water, quantitative filtration and redispersion of Cryptosporidium oocysts(More)
Acoustic bubble-size distributions have been determined using a pulsed ultrasound method at different ultrasound powers and frequencies. It was observed that the mean bubble size increased with increasing acoustic power and decreased with increasing ultrasound frequency. It was also recognized that the mean size of bubbles emitting sonoluminescence was(More)
Ibuprofen (IBP) is a widely used analgesic and anti-inflammatory drug and has been found as a pollutant in aqueous environments. The sonolytic, photocatalytic and sonophotocatalytic degradations of IBP in the presence of homogeneous (Fe(3+)) and heterogeneous photocatalysts (TiO(2)) were studied. When compared with sonolysis and photocatalysis, a higher(More)
High-speed photographic observations of cavitation occurring under a low-frequency (21 kHz) sonotrode tip in the presence of an additional, high-frequency (355 kHz) ultrasound source have been made in water and in dilute aqueous solute solutions. Acoustic emission spectra were measured to support the visual observations. It was seen that a nucleating effect(More)