Sonoluminescence In Water Research Articles

The effect of KZK pressure equation on the sonoluminescence in water and fat tissues

The effect of the produced light flashes from sonoluminescence (SL) on the fat tissue and water is studied. By using KZK equation as an essential equation for calculating the thermal source in bio-liquids, the effective bubble parameters in quasi-adiabatic model are calculated and compared in these systems. It is noticed that the temperature and the intensity for fat tissue are about 30% and 38% less than the ones for water respectively. These results are almost in good agreement with the only experimental measurement denoting less SL temperature in bio-liquids which present more suitable condition for using SL in such applications.

Effects of fluid viscosity on a moving sonoluminescing bubble

Based on the quasi-adiabatic model, the parameters of the bubble interior for a moving single bubble sonoluminescence in water, adiponitrile, and N-methylformamide are calculated for various fluid viscosities. By using a complete form of the hydrodynamic force, the bubble trajectory is calculated for a moving single bubble sonoluminescence (m-SBSL). It is found that as the fluid viscosity increases, the unique circular path changes to an ellipsoidal and then linear form and along this incrementally increase of viscosity the light intensity increases. By using the Bremsstrahlung model to describe the bubble radiation, gradual increase of the viscosity results in brighter emissions. It is found that in fluids with higher viscosity the light intensity decreases as time passes.

A unique circular path of moving single bubble sonoluminescence in water

Based on a quasi-adiabatic model, the parameters of the bubble interior for a moving single bubble sonoluminescence (m-SBSL) in water are calculated. By using a complete form of the hydrodynamic force, a unique circular path for the m-SBSL in water is obtained. The effect of the ambient pressure variation on the bubble trajectory is also investigated. It is concluded that as the ambient pressure increases, the bubble moves along a circular path with a larger radius and all bubble parameters, such as gas pressure, interior temperature and light intensity, increase. A comparison is made between the parameters of the moving bubble in water and those in N-methylformamide. With fluid viscosity increasing, the circular path changes into an elliptic form and the light intensity increases.

Data collapse of the spectra of water-based stable single-bubble sonoluminescence

In the early days of stable single-bubble sonoluminescence, it was strongly debated whether the emission was blackbody radiation or whether the bubble was transparent to its own radiation (volume emission). Presently, the volume emission picture is nearly universally accepted. We present new measurements of spectra with apparent color temperatures ranging from 6000 to 21 000 K. We show through data collapse that within experimental uncertainty, apart from a constant, the spectra of strongly driven stable single-bubble sonoluminescence in water can be written as the product between a universal function of wavelength and a functional form that only depends on wavelength and apparent temperature but has no reference to any other parameter specific to the experimental situation. This remarkable result does question our theoretical understanding of the state of the plasma in the interior of strongly driven stable sonoluminescent bubbles.

Comparison of Xe single bubble sonoluminescence in water and sulfuric acid

Using the equations of fluid mechanics with proper boundary conditions and taking account of the gas properties, we can numerically simulate the process of single bubble sonoluminescence, in which electron–neutral atom bremsstrahlung, electron—ion bremsstrahlung and recombination radiation, and the radiative attachment of electrons to atoms and molecules contribute to the light emission. The calculation can quantitatively or qualitatively interpret the experimental results. We find that the accumulated heat energy inside the compressed gas bubble is mostly consumed by the chemical reaction, therefore, the maximum degree of ionization inside Xe bubble in water is much lower than that in sulfuric acid, of which the vapour pressure is very low. In addition, in sulfuric acid much larger pa and R0 are allowed which makes the bubbles in it much brighter than that in water.

Sonoluminescence of terbium chloride in an H2O-D2O mixture

The effect of solvent deuteration on the multibubble sonoluminescence (SL) of an aqueous solution of terbium chloride was studied. The dependence of the intensity of the characteristic SL of the TbIII ion on the composition of an H2O-D2O mixture is similar to an analogous dependence of its photoluminescence (PL) but with a much smaller isotope effect. In pure D2O, the SL intensity increases by 4 times only compared to the SL in water, while the PL intensity increases by 10 times. The mechanism of inner-bubble excitation of lanthanide ions is considered. According to this mechanism, an additional “heterogeneous” channel of quenching of excited TbIII ions appears, which is absent for PL. The proposed model satisfactorily describes the experimental data on the effect of solvent deuteration on the SL intensity.

Observation of fluorescence emissions from single-bubble sonoluminescence in water doped with quinine

Sonoluminescence is a phenomenon involving the transduction of sound into light. The detailed mechanism as well as the energy-focusing potentials are not yet fully explored and understood. So far only optical photons are observed, while emissions in the ultra-violet range are only inferred. By doping the fluorescent dye quinine into water with dilute sulphuric acid, the high energy photons can be converted into the optical photons with slower decay constants. These sonoluminescence and fluorescent emissions were observed in coincidence, and the emitted signals of the two modes can be differentiated by their respective timing profiles. Plans for using this technique as a diagnostic tool to quantitatively study ultra-violet and other high energy emissions in sonoluminescence are discussed.

On the emitters of sulfuric acid sonoluminescence

A comparative study of the sonoluminescence spectra of water and argon-saturated aqueous H2SO4 solutions was carried out. At an H2SO4 concentration of 18 mol L−1, the sulfuric acid sonoluminescence is fifty times more intense than water sonoluminescence. The sulfuric acid luminescence spectrum differs from the water sonoluminescence spectrum caused by the emission of excited water molecules and OH radicals from the gas phase of cavitation bubbles. The sulfuric acid sonoluminescence spectrum exhibits maxima at 330, 420, 500, and 630 nm. Emitters of sonoluminescence of sulfuric acid are the singlet (330–340 nm) and triplet (∼420 nm) excited SO2 molecules formed by sonolysis of H2SO4 molecules. Another product of sonolysis of H2SO4, atomic oxygen, is assumed to be responsible for the luminescence at λ = 630 nm.

Effect of Solutes on Single-Bubble Sonoluminescence in Water

Low concentrations of short chain aliphatic alcohols and organic acids and bases suppress single-bubble sonoluminescence (SBSL) in water. The degree of SL quenching increases with the length of the aliphatic end of the alcohol, and is related to the concentration of the alcohol at the bubble/water interface. The light is preferentially quenched in the shorter wavelength region of the spectrum. Radius−time measurements of the bubble are not dramatically affected by the low levels of alcohol used. Butyric acid and propylamine behave in the same manner, but only in their neutral forms, indicating that the SBSL suppression is due to processes occurring within the bubble.

Role of very-high-frequency excitation in single-bubble sonoluminescence

The fundamental and tenth harmonics were used to produce stable single-bubble sonoluminescence in water. By varying the phase difference between the harmonics, it was possible to enhance the sonoluminescence light emission by as much as a factor of 2.7 compared with single-frequency excitation. Absolute measurements of the bubble radius evolution were carried out using the two-detector technique. Unlike previous observations, these measurements and complementary fits of the Rayleigh-Plesset equation reveal that the maximum bubble radius does not change significantly with phase angle between the harmonics. Therefore, increased sonoluminescence intensity does not have to correlate with increases in maximum bubble radius prior to collapse. We believe that a more violent bubble collapse rate (driven by the very-high-frequency component) is responsible for the enhanced light emission under this type of mixed excitation. It was further found that the presence of the tenth-harmonic frequency component led to significant enhancements in the stability of the bubble undergoing sonoluminescence. This allowed the bubble to be driven at the fundamental frequency at 2.0 bars pressure amplitudes, which are significantly above often-reported thresholds of 1.4 bar itself, thereby leading to increased levels of light emission (by more than 250%).

Temperature of Multibubble Sonoluminescence in Water

Sonoluminescence (SL) spectra were collected from water doped with several organic liquids at low concentrations. Most of the organic substances studied show emission from C2 and an overall decrease in the intensity relative to SL from pure water. This decrease is due to the consumption by the organic substrates of hydroxyl radicals and other incipient emitting species produced during sonolysis. Small concentrations of carbon disulfide do not lead to emission from C2 but do cause an increase in SL intensity across the spectral window, most likely due to its own fluorescence. Carbon tetrachloride does not change the intensity of water sonoluminescence but does exhibit C2 emission. This indicates that the dissociation of carbon tetrachloride inside the cavitation bubble is independent of the products of water sonolysis. Benzene shows the strongest C2 emission and was studied in the greatest detail. The emission of excited-state C 2 arising from the sonication of benzene/water mixtures at 20 kHz was used to determine an effective emission temperature during cavitation in water. Interband analysis of the two C2 bands observed during irradiation of water/benzene mixtures at 278 K under Ar indicates an emission temperature of 4300 ( 200 K. High-intensity ultrasonic vibrations in liquids are accompanied by cavitation: the formation of vapor/gas filled bubbles that pulsate in a highly nonlinear manner. The energy stored during the growth of the bubble in the rarefaction phase of the acoustic field is released when the bubble violently collapses in the positive phase of the acoustic field. This is manifested as acoustic noise, shock waves, chemical reactions, and the emission of light (sonoluminescence, SL). 1 This violent collapse is predicted to generate a hot spot of thousands of Kelvin within the bubble, 1-5 but there have to date been only a limited number of experimental measurements of the temperature of this hot spot. 6-11 Although the sonoluminescence of water has been studied for more than 50 years, 12,13 reliable measurements of the effective temperature during aqueous cavitation remain unresolved. Given the importance of aqueous cavitation to numerous issues (sonography and bioeffects of ultrasound, sonochemical remediation of aqueous pollutants, synthetic applications of sonochemistry, etc. 14 ), we decided to apply our previous spectroscopic analysis of sonoluminescence from nonaqueous liquids to aqueous solutions doped with small amounts of hydrocarbons. MBSL (multibubble sonoluminescence, light emission from cavitation clouds) spectra from dilute mixtures of organic liquids in water were collected. We have analyzed the emission from excited states of C2 and find that cavitation in benzene/water solutions at 20 kHz has an effective emission temperature of 4300 ( 200 K. Sonoluminescence from water was discovered in the early 1930s when Marinesco and Trillat 12 found that a photographic plate could be fogged in the presence of a cavitation field, and both Frenzel and Schultes 13 and Zimakov 13 subsequently observed this emission using the unaided eye. Subsequent

Effect of a magnetic field on sonoluminescence.

The effect of a magnetic field on single-bubble sonoluminescence in water reported experimentally by Young, Schmiedel, and Kang [Phys. Rev. Lett. 77, 4816 (1996)] is studied theoretically. It is suggested that bubble dynamics is affected by the magnetic field because moving water molecules of the liquid suffer torque due to the Lorentz force acting on their electrical dipole moment, which results in the transformation of some of the kinetic energy into heat. It is shown that the magnetic field acts as if the ambient pressure of the liquid were increased. It is suggested that the effect increases as the amount of the liquid water increases. It is predicted that nonpolar liquid such as dodecane exhibits no effect of the magnetic field.

Single-bubble sonoluminescence in water during transitions from hypergravity to low gravity on NASA’s KC-135 aircraft and laser-beam extinction methods for studying bubble dynamics

The sound field which drives SBSL also provides the radiation force which counteracts the average buoyancy of the bubble. One consequence is that the location of the bubble should be altered by the effective acceleration of gravity ge. Variations in ge may alter the physical processes giving rise to luminescence. This group’s previous experiments have confirmed that SBSL is not automatically quenched in the reduced and enhanced ge conditions in an aircraft undergoing parabolic flight trajectories [D. B. Thiessen et al., in Proc. of the 4th Microgravity Fluid Phys. Conf. (NASA, 1998), pp. 379–383]. The new experiments were carried out with the SBSL chamber in contact with a constant-pressure gas-filled chamber. During intervals of negligible drift in the SBSL intensity, there can be a rapid intensity rise (with a relaxation time of about 5 s) of about 4% as ge is decreased from 1.8 to near 0 g, but the increase is not seen in all data sets. In related work, diagnostics based on monitoring laser-beam extinction with a photocell [J. S. Stroud and P. L. Marston, J. Acoust. Soc. Am. 94, 2788–2792 (1993)] is applied to SBSL bubbles in the laboratory. [Work supported by NASA.]

Spectra of single-bubble sonoluminescence in water and glycerin-water mixtures

A single gas bubble, acoustically levitated in a standing-wave field and oscillating under the action of that field, can emit pulses of blue-white light with duration less than 50 ps. Measurements of the spectrum of this picosecond sonoluminescence with a scanning monochrometer are reported for air bubbles levitated in water and in glycerin-water mixtures. While the spectrum has been reported previously by others for air bubbles in water, the spectrum for air bubbles in water-glycerin mixtures has not. Expected emission lines from glycerin were conspicuously absent, suggesting a different mechanism for light production in single-bubble sonoluminescence. Other conclusions are the spectrum for air bubbles in water is consistent with that previously reported, the radiated energy decreases as the glycerin concentration increases, and the peak of the spectrum appears to shift to longer wavelengths for the water-glycerin mixtures. \textcopyright{} 1996 The American Physical Society.

Cavitation threshold dependence on the rate of the transducer voltage variation

The cavitation thresholds of subharmonic emission and of sonoluminescence in water have been measured in a focused ultrasound beam by two different methods: (1) by increasing the transducer voltage at different rates; (2) by keeping a chosen constant transducer voltage and waiting for the appearance of the subharmonic or of the sonoluminescence. The thresholds increase with increasing the rate of voltage increase. The waiting time diminishes with the increase of the chosen threshold voltage.

Sonochemistry and sonoluminescence: effects of external pressure

The oxidation of iodide by 1-MHz continuous ultrasound and the sonoluminescence in water created by pulsed ultrasound were investigated in the pressure range from 0.7 to 3 bar. At low intensities, the chemical yield and the luminescence intensity decrease with increasing pressure. At higher intensities the yields increase moderately with increasing pressure. There is a critical intensity above which a steep decrease in the chemical and luminescence yields occurs. This critical intensity is strongly shifted to higher values with increasing pressure

Sonoluminescence in water and agar gels during irradiation with 0.75 mhz continuous-wave ultrasound

Free radicals, detected as light emissions (sonoluminescence), can be produced in both simple aqueous systems and agar gels by irradiation with 0.75 MHz continuous-wave (CW) ultrasound using acoustic pressures as low as 200 KPa. Although the acoustic pressures necessary for free radical formation in tap water gels (200 KPa), are considerably higher than those required for the formation of macroscopic visible bubbles (26 KPa), the sonoluminescence threshold (0.5 W/cm −2 SATA equivalent) falls at the lower end of the intensity range (0.5–3 W/cm −2) commonly used by ultrasonic physiotherapy equipment. In respect of the overall features of cavitation processes, agar gels appear to be suitable simple systems in which to model cavitation in vivo. However, cavitation processes leading to sonoluminescence are themselves complex as illustrated by the findings that small changes in ionic composition or pH have a significant effect on both the acoustic pressure threshold and the extent of sonoluminescence above this threshold.

Spatial, Temporal and Spectral Observations of Sonoluminescence by Means of Image Intensification

Sonoluminescence (SL) is a weak light emission occurring when certain liquids are cavitated by acoustical waves. There is at present no single theory that can accommodate all of the experimental observations of this luminescence. Dark adapted eyes, photographic films, and photomultipliers have been used to observe the phenomenon when various transducers and liquids have been used, but little or no spatial information has been available. Long exposures on conventional film have yielded some evidence for standing wave patterns and some information on spectral distributions. The purpose of this paper is to provide a brief history of observations of the phenomenon and the hypotheses put forth to explain it, and to describe some initial experimental results obtained using image intensification to determine the spatial, temporal and spectral characteristics associated with sonoluminescence in water.

Laser sonoluminescence in water under increased hydrostatic pressure

Laser sonoluminescence in water under increased hydrostatic pressure

Light emission from cavitating water

Light has been detected from the vaporous cavitation induced in flowing tap water by a fall in pressure as it passed through the constriction of a Venturi tube. The intensity of this light was several orders of magnitude less than that of the corresponding `sonoluminescence', the light emitted from vaporous cavitation induced in engassed liquids by an intense ultrasonic field. The light could be enhanced by the addition of a small quantity of carbon disulphide; sonoluminescence in water is also enhanced by the addition of this liquid. The intensity of the cavitation and of the light was also enhanced by increasing the proportion of air in the tap water, but if too much air was introduced the cavitation and light emission ceased.