The effect of bulk solution temperature on the intensity and spectra of water sonoluminescence

Didenko, Yuri T.; Nastich, D. N.; Pugach, S. P.; Polovinka, Yu. A.; Kvochka, V. I.

doi:10.1016/0041-624x(94)90083-3

Cited by 60 publications

(32 citation statements)

References 14 publications

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“…11,13,[19][20][21][22][23][24][25] The condition is that of a spherical bubble in liquid water irradiated by ultrasound whose wavelength is over an order of magnitude longer than the bubble radius. Computer simulations are performed for various ambient radii of a bubble (R 0 ) and various amplitudes of ultrasound (p a ) for each frequency of ultrasound.…”

Section: Resultsmentioning

confidence: 99%

Influence of ultrasonic frequency on multibubble sonoluminescence

Yasui

2002

The Journal of the Acoustical Society of America

179

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Computer simulations of bubble oscillations are performed under conditions of multibubble sonoluminescence (MBSL) in water for various ultrasonic frequencies. The range of the ambient bubble radius for sonoluminescing bubbles narrows as the ultrasonic frequency increases; at 20 kHz it is 0.1-100 microm while at 1 MHz it is 0.1-3 microm. At 1 MHz, any sonoluminescing bubble disintegrates into a mass of smaller bubbles in a few or a few tens of acoustic cycles, while at 20 kHz and 140 kHz some sonoluminescing bubbles are shape stable. The mechanism of the light emission also depends on the ultrasonic frequency. As the ultrasonic frequency increases, the amount of water vapor trapped inside bubbles at the collapse decreases. As a result, MBSL originates mainly in plasma emissions at 1 MHz while it originates in chemiluminescence of OH radicals and plasma emissions at 20 kHz.

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Section: Resultsmentioning

confidence: 99%

Influence of ultrasonic frequency on multibubble sonoluminescence

Yasui

2002

The Journal of the Acoustical Society of America

179

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“…In this case sonoluminescence is due to either equilibrium thermal emission or deactivation of excited molecules that are produced in the CB by inelastic collisions of high energy species. 7 The electric theory explains sono luminescence by electric breakdown in a CB on compres sion or splitting. 1 Earlier, 6 we observed sonoluminescence of air satu rated aqueous sulfuric acid solutions.…”

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confidence: 99%

On the emitters of sulfuric acid sonoluminescence

2005

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A comparative study of the sonoluminescence spectra of water and argon saturated aque ous H 2 SO 4 solutions was carried out. At an H 2 SO 4 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 SO 2 molecules formed by sonolysis of H 2 SO 4 molecules. Another product of sonolysis of H 2 SO 4 , atomic oxygen, is assumed to be responsible for the luminescence at λ = 630 nm.The mechanism of ultrasonic cavitation in liquids has been studied for about a century. Meanwhile, the essence of high energy processes occurring in cavitation bubbles (CBs), which are responsible for sonoluminescence and sonochemical reactions, are still to be clarified. 1 Studies of sonoluminescence of aqueous solutions of various com pounds including inorganic acids in comparison with the corresponding data for water are expected to clarify the mechanism of sonoluminescence, to find ways of en hancement of sonoluminescence intensity, and to dis close fields of application of this phenomenon.The effect of ultrasonic cavitation on aqueous solu tions of inorganic acids has been studied. 2-6 In argon saturated H 2 SO 4 solutions (at acid concentrations exceed ing 9 mol L -1 ) the H 2 SO 4 molecules decompose into sul fur, SO 2 , and H 2 S. 2 It was assumed 3 that breakdown of H 2 SO 4 molecules is due to energy transfer from the ex cited species produced in CBs to the H 2 SO 4 molecules and HSO 4 -ions on the CB walls. In concentrated solu tions, the H 2 SO 4 molecules present within CBs can also evaporate and interact with electrons produced 2 in the gas phase on elecrical breakdown of CBs. No sonolumine scence of sulfuric acid has been studied by the authors of Ref. 2. Sonolysis of hydrochloric and phosphoric acids was also investigated 3,4 without studying sonolumine scence.A sonoluminescence study 5 of argon saturated aque ous nitric acid solutions revealed a selective quenching of the 310 nm band of • OH radicals in the sonoluminescence spectrum on an increase in the HNO 3 concentration in the range 0-0.9 mol L -1 and an increase in the intensity of an H 2 O* luminescence band near λ = 275 nm. Further increase in the HNO 3 concentration leads to a decrease in the intensity of sonoluminescence throughout the entire spectrum.Thus, only a few studies on sonoluminescence of aque ous solutions of inorganic acids are available. At the same time, information on sonoluminescence of aqueous solu tions of strong electrolytes could clarify a "dispute" be tween the thermal and electric theories of sonolumine scence. According to the former theory, quasi adiabatic compression of a CB leads to heating o...

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“…It is well known that sludge hydrolysis increases with the reaction temperature, and cavitation can also be achieved at lower acoustic power if the reaction temperature is high. On the other hand, the physical and chemical effects resulting from the collapse of cavitation bubbles under sonication are reduced due to the increase in vapor pressure associated with the liquid [22,[27][28][29]. Entezari and Kruus [30] noted that rate of KI oxidation decreases linearly with increasing temperature with 20 kHz ultrasound.…”

Section: Sequential Treatment Of Heat and Ultrasonic Cavitation For Smentioning

confidence: 96%

Characteristics of sludge hydrolysis by ultrasound and thermal pretreatment at low temperature

Kim¹,

Youn²

2011

Korean J. Chem. Eng.

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Ultrasonic treatment and thermal treatment at low temperature were employed together to analyze and compare the effect of temperature on ultrasonic sludge hydrolysis. Waste activated sludge was more susceptible to ultrasound than anaerobic sludge and primary sludge. In ultrasonic treatment of waste activated sludge for 1 hour, ∆SCOD/ (−∆VSS) ratio decreased from 2.40 to 0.44, indicating that high COD components were solubilized faster than the low COD components. Ultrasonic treatment increased the temperature significantly and the heat effect on sludge hydrolysis was not negligible. Primary sludge was more susceptible to heat than waste activated sludge. A sequential treatment of heat and ultrasound of primary sludge showed that hydrolysis efficiency was more affected by the ultrasonic power than the temperature and the time duration. In case of waste activated sludge, the overall hydrolysis efficiency increased with the temperature up to 50 o C, and it remained almost constant at higher temperature. From the results the contribution of shear force by cavitation bubbles decreased at higher temperature. The effects of shear and heat in ultrasonic sludge treatment need to be analyzed separately for the optimum sludge pretreatment.

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The effect of bulk solution temperature on the intensity and spectra of water sonoluminescence

Cited by 60 publications

References 14 publications

Influence of ultrasonic frequency on multibubble sonoluminescence

Influence of ultrasonic frequency on multibubble sonoluminescence

On the emitters of sulfuric acid sonoluminescence

Characteristics of sludge hydrolysis by ultrasound and thermal pretreatment at low temperature

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