Correlation between Sonoluminescence, Sonochemistry and Cavitation Noise Spectra

Influence of Surface Active Solute on Ultrasonic Waveform Distortion in Liquid Containing Air Bubbles

“…It is found from Figure a that the waveform is subject to distortion at high power (9.7 W), and the trend is similar for SDS and water. This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes . The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure and the spectral components seen in Figure c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above.…”

“…This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes. 24 The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure 5 and the spectral components seen in Figure 7c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above. It is seen in Figure 6 that the detected power for 1 mM SDS + 0.1 M NaCl is almost the same as that for 1 mM SDS except at the highest power setting.…”

Influence of Surface Active Solute on Ultrasonic Waveform Distortion in Liquid Containing Air Bubbles

“…It is found from Figure a that the waveform is subject to distortion at high power (9.7 W), and the trend is similar for SDS and water. This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes . The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure and the spectral components seen in Figure c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above.…”

“…This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes. 24 The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure 5 and the spectral components seen in Figure 7c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above. It is seen in Figure 6 that the detected power for 1 mM SDS + 0.1 M NaCl is almost the same as that for 1 mM SDS except at the highest power setting.…”

Acoustic Emission Spectra from 515 kHz Cavitation in Aqueous Solutions Containing Surface-Active Solutes

“…The maximum intensity of the peak is relatively insensitive to SDS concentration. Similar changes inacoustic emission were observed by Segebarth et al, who interpreted their spectra as a narrowing of the second harmonic peak as well as a reduction in the signal at the harmonic frequency. In this work, the harmonic peaks are much narrower (∼200−300 Hz, compared with 7−14 kHz from the data of Segebarth et al), reflecting perhaps the different types of hydrophone used for the measurements.…”

Multibubble Sonoluminescence in Ethylene Glycol/Water Mixtures

“…The resultant effects of the surfactants on MBSL shown in Figures to are similar to those seen previously when these types of surfactants were added to water. , The rise in MBSL with the addition of the ionic surfactants SDS and CPBr to the mixed solvent seen in Figure is consistent with these charged surfactants adsorbing to active bubbles, thereby creating an electrical double layer, and then through interbubble electrostatic interactions retarding bubble–bubble coalescence and reducing the density of bubble clouds. Both situations will have the effect of increasing the population of active bubbles and therefore also the MBSL signal.…”

“…It can be seen that in water and below 50% (v/v) mixtures, following the initial rise in the signal intensity, there is a decline in the SL signal at SDS concentrations above about 2 mM. This has been previously noted and is attributed to the change in the electrostatic interactions between charged bubbles as the ionic strength of the solution is raised. − This will be discussed in greater detail later. In neat ethylene glycol the SL intensity increases with added surfactant, reaching a maximum at around 10–20 mM, and then remains approximately constant at concentrations above that amount.…”

Influence of Surface Active Solute on Ultrasonic Waveform Distortion in Liquid Containing Air Bubbles

“…It is found from Figure a that the waveform is subject to distortion at high power (9.7 W), and the trend is similar for SDS and water. This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes . The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure and the spectral components seen in Figure c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above.…”

“…This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes. 24 The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure 5 and the spectral components seen in Figure 7c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above. It is seen in Figure 6 that the detected power for 1 mM SDS + 0.1 M NaCl is almost the same as that for 1 mM SDS except at the highest power setting.…”

Acoustic Emission Spectra from 515 kHz Cavitation in Aqueous Solutions Containing Surface-Active Solutes

“…The maximum intensity of the peak is relatively insensitive to SDS concentration. Similar changes inacoustic emission were observed by Segebarth et al, who interpreted their spectra as a narrowing of the second harmonic peak as well as a reduction in the signal at the harmonic frequency. In this work, the harmonic peaks are much narrower (∼200−300 Hz, compared with 7−14 kHz from the data of Segebarth et al), reflecting perhaps the different types of hydrophone used for the measurements.…”

Multibubble Sonoluminescence in Ethylene Glycol/Water Mixtures

“…The resultant effects of the surfactants on MBSL shown in Figures to are similar to those seen previously when these types of surfactants were added to water. , The rise in MBSL with the addition of the ionic surfactants SDS and CPBr to the mixed solvent seen in Figure is consistent with these charged surfactants adsorbing to active bubbles, thereby creating an electrical double layer, and then through interbubble electrostatic interactions retarding bubble–bubble coalescence and reducing the density of bubble clouds. Both situations will have the effect of increasing the population of active bubbles and therefore also the MBSL signal.…”

“…It can be seen that in water and below 50% (v/v) mixtures, following the initial rise in the signal intensity, there is a decline in the SL signal at SDS concentrations above about 2 mM. This has been previously noted and is attributed to the change in the electrostatic interactions between charged bubbles as the ionic strength of the solution is raised. − This will be discussed in greater detail later. In neat ethylene glycol the SL intensity increases with added surfactant, reaching a maximum at around 10–20 mM, and then remains approximately constant at concentrations above that amount.…”

Influence of Surface Active Solute on Ultrasonic Waveform Distortion in Liquid Containing Air Bubbles

“…It is found from Figure a that the waveform is subject to distortion at high power (9.7 W), and the trend is similar for SDS and water. This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes . The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure and the spectral components seen in Figure c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above.…”

“…This is consistent with literature reports of higher cavitation noise in 1 mM SDS solutions in the presence of electrolytes. 24 The results for SL in 1 mM SDS + 0.1 M NaCl shown in Figure 5 and the spectral components seen in Figure 7c indicate that there is an intermediate region of applied power from the threshold for noise (1.5 W) to that for SL (8.5 W), which is similar to at the case for 10 mM SDS described above. It is seen in Figure 6 that the detected power for 1 mM SDS + 0.1 M NaCl is almost the same as that for 1 mM SDS except at the highest power setting.…”

Acoustic Emission Spectra from 515 kHz Cavitation in Aqueous Solutions Containing Surface-Active Solutes

“…The maximum intensity of the peak is relatively insensitive to SDS concentration. Similar changes inacoustic emission were observed by Segebarth et al, who interpreted their spectra as a narrowing of the second harmonic peak as well as a reduction in the signal at the harmonic frequency. In this work, the harmonic peaks are much narrower (∼200−300 Hz, compared with 7−14 kHz from the data of Segebarth et al), reflecting perhaps the different types of hydrophone used for the measurements.…”

Multibubble Sonoluminescence in Ethylene Glycol/Water Mixtures

“…The resultant effects of the surfactants on MBSL shown in Figures to are similar to those seen previously when these types of surfactants were added to water. , The rise in MBSL with the addition of the ionic surfactants SDS and CPBr to the mixed solvent seen in Figure is consistent with these charged surfactants adsorbing to active bubbles, thereby creating an electrical double layer, and then through interbubble electrostatic interactions retarding bubble–bubble coalescence and reducing the density of bubble clouds. Both situations will have the effect of increasing the population of active bubbles and therefore also the MBSL signal.…”

“…It can be seen that in water and below 50% (v/v) mixtures, following the initial rise in the signal intensity, there is a decline in the SL signal at SDS concentrations above about 2 mM. This has been previously noted and is attributed to the change in the electrostatic interactions between charged bubbles as the ionic strength of the solution is raised. − This will be discussed in greater detail later. In neat ethylene glycol the SL intensity increases with added surfactant, reaching a maximum at around 10–20 mM, and then remains approximately constant at concentrations above that amount.…”