School of Chemistry - Research Publications
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ItemThe use of ultrasonic cleaning for ultrafiltration membranes in the dairy industryMuthukumaran, S ; Yang, K ; Seuren, A ; Kentish, S ; Ashokkumar, M ; Stevens, GW ; Grieser, F (ELSEVIER SCIENCE BV, 2004-10-01)
ItemDetermination of the size distribution of sonoluminescence bubbles in a pulsed acoustic fieldLee, J ; Ashokkumar, M ; Kentish, S ; Grieser, F (AMER CHEMICAL SOC, 2005-12-07)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.
ItemSonochemical synthesis of graphene oxide supported Pt-Pd alloy nanocrystals as efficient electrocatalysts for methanol oxidationNeppolian, B ; Saez, V ; Gonzalez-Garcia, J ; Grieser, F ; Gomez, R ; Ashokkumar, M (SPRINGER, 2014-11-01)
ItemHydrodynamic boundary conditions and dynamic forces between bubbles and surfacesManor, O ; Vakarelski, IU ; Tang, X ; O'Shea, SJ ; Stevens, GW ; Grieser, F ; Dagastine, RR ; Chan, DYC (AMER PHYSICAL SOC, 2008-07-11)Dynamic forces between a 50 microm radius bubble driven towards and from a mica plate using an atomic force microscope in electrolyte and in surfactant exhibit different hydrodynamic boundary conditions at the bubble surface. In added surfactant, the forces are consistent with the no-slip boundary condition at the mica and bubble surfaces. With no surfactant, a new boundary condition that accounts for the transport of trace surface impurities explains variations of dynamic forces at different speeds and provides a direct connection between dynamic forces and surface transport effects at the air-water interface.
ItemThe mechanism of sonochemical degradation of a cationic surfactant in aqueous solutionSingla, R ; Grieser, F ; Ashokkumar, M (ELSEVIER, 2011-03-01)The sonochemical degradation of the cationic surfactant, laurylpyridinium chloride (LPC), in water was studied at concentrations of 0.1-0.6 mM, all below its critical micelle concentration (15 mM). It has been found that the initial step in the degradation of LPC occurs primarily by a pyrolysis pathway. Chemical analysis of sonicated solutions by gas chromatography, electrospray mass spectrometry, and high performance liquid chromatography reveals that a broad range of decomposition products, hydrocarbon gases and water-soluble species, are produced. Propionamide and acetamide were identified as two of the degradation intermediates and probably formed as the result of the opening of the pyridinium ring following OH radical addition. Most of the LPC is eventually converted into carboxylic acids. The complete mineralization of these carboxylic acids by sonolysis is however a comparatively slow process due to the hydrophilic nature of these low molecular weight products.