Ultrasonic, effect

The transducers are typically mounted on an outside wall of the cleaning tank, but may also be mounted on the inside of the tank below the solution level in a sealed container. Alkaline cleaning solutions are typically at the same concentration and temperature as for a normal immersion cleaner, but the time required to clean may be less because of the ultrasonic effect. Like electrocleaning, ultrasonic cleaning produces an extremely clean surface. The main drawback is the relatively high cost. 

Atobe, M., Sasahira, M. and Nonaka, T., 2000, Ultrasonic effects on Electro-organic Processes part 42. Product selectivity control in reductive homo and cross couplng of acrylonitrile . Paper presented on the 197" meeting of the Electrochemical Society May 2000, Toronto Camab Abstract no. 108. 

Asami R, Atobe M, Fuchigami T (2006) Ultrasonic effects on electroorganic processes. Part 27. Electroreduction of acrylonitrile at suspended lead particle-electrode. Ultrason Sonochem 13 19-23, and the series... 

According to Ando et al. (2000), the sonolytic acetoxylation of styrene by lead tetraacetate follows the ion-radical mechanism. Lead tetraacetate was not subject to the sonication influence. The ultrasonic effect facilitates electron transfer from styrene (the nonmetallic donor) to lead tetraacetate. 

Moreover, in the divided cell the exo.endo ratio of bromosilanes was 91 9 in the anode compartment bnt only 52 48 in the cathode compartment. Thus, the nature of the ultrasonic effect was explained assuming that beside the electrochemical silylation at the cathode, a parallel silylation process occurs at a magnesium anode, namely the silylation by 70 of an intermediate Grignard reagent produced from dibromide 69. It appears as a rare example of the anodic reduction However, the increase in the current density dnring electrolysis cansed a decrease in the apparent current efficiency. This observation indicates a chemical natnre of the anodic process. Of course, the ultrasonic irradiation facihtates the formation of the organomagnesium intermediate at the sacrificial anode and the anthors reported a similar ultrasonic effect for the nonelectrochemical but purely sonochemical... 

In the second part of this review we make an attempt to systematize the results of investigations into ultrasonic effects upon molten polymers carried out recently, and to prognosticate potential spheres of application for phenomena revealed therein. Note that this sphere has not been reviewed yet in literature, the occurrence of original publications is very low and the field of research is relatively narrow. 

Karelin YuM, Mazurenko YuS, Peshkovsky SL (1973) Device for ultrasonic effect upon flow of molten polymers. In Polymer equipment and processing of plastic masses, Tehnika, Kiev, P 31... 

Ultrasonic Effects on Flow through Porous Media... 

Gaunaurd, G. C. and Uberall, H., "Resonance Effects and Ultrasonic Effective Properties of Particulate Composites,"... 

ULTRASONIC EFFECT ON THE MORPHOLOGY AND ACTIVITY OF METAL NANOPARTICLES... 

Ultrasonic effect on the catalytic efficiency of platinum nanoparticles in poly vinylpyrroUdone or ethyleneglycol solutions... 

Ultrasonic manipulation of particles in suspension lies at the heart of SINNMR. The incoherent motion necessary for line-narrowing is thought to be generated from a number of ultrasonic effects. 

The origin of ultrasonic effect upon carboxylate electrooxidation is not straightforward to establish in view of the complex mechanism of the reaction with different kinetic regimes, the loss of carbon dioxide, and also the role of adsorption... 

Salimi, A., Banks, C.E., and Compton, R.G. (2003). Ultrasonic effects on the electroreduction of oxygen at a glassy carbon anthraquinone-modified electrode. The Koutecky-Levich equation applied to insonated electrocatalytic reactions. Phys. Chem. Chem. Phys., 5, 3988-93. 

Aerosol can be separated by size using devices such as cyclones, classical impactors, virtual impactors, and filters before detection. These same components can also be used for aerosol concentration and collection as described below. Other methods involving electrostatic and ultrasonic effects are being investigated for aerosol concentration and separation, but these methods are less developed and are not available for near-term deployment. 

The number of industrial acoustic heads is now rather limited in comparison with the availability of forming tools working without the ultrasonic affect, despite the significant enhancement of performance. The existing construction allows application of the ultrasonic effect to the production of film, sheets and tube structures, whereas the demand for high-quality profile items is increasing for other sections. 

Sonochemical enhancement of reaction rates is caused by a phenomenon called cavitation. Therefore, we largely confine the treatment in this chapter to the chemical and reaction engineering (scale-up) aspects of cavitation and its associated effects (see Shah et al., 1999, for a detailed treatment). An alternative means of achieving the same result is by mimicking the ultrasonic effect by inducing hydrodynamic cavitation. Because of the practical importance of this technique, we conclude the chapter by outlining its main features. 

It can be shown that cavitation probably does not occur at the equilibrium bubble size at atmospheric pressure. However, the bubble can be driven to cavitation by reducing the pressure. Conversely, higher pressures require greater ultrasonic energy to induce cavitation. This leads to a larger intensity of cavita-tional collapse and therefore to a considerably enhanced ultrasonic effect, as demonstrated in the oxidation of indane to indane-l-one using potassium permanganate (Cum et al., 1988). 

In addition to the important factors previously considered which influence sono-chemical reactions, a few others need to be considered as well. Among these are surface tension, viscosity, and solubility. The viscosity of a liquid increases as the pressure is increased or the temperature is decreased. Solvents with higher viscosity require higher amplitudes (or power) for cavitation to occur. In other words, cavitation becomes difficult to induce in high viscosity liquids. This is a situation that enhances the ultrasonic effect, and hence higher viscosities should normally lead to greater rate enhancements. 

In each of these categories, four broad types of the ultrasonic effect on organic... 

Chlorine, hydrogen, and oxygen evolution at a sonicated Pt electrode Cyclic voltammetry 38 kHz cleaning bath Gas evolution is enhanced under sonication due to removal of adsorbed species oxygen evolution shows little ultrasonic effect 63... 

A. (2013) Supramolecular glucose oxidase-SWNT conjugates formed by ultrasonication effect of tube length, functionalization and processing time. / Nanobiotechnol., 11, 1-12. 

The effect of ultrasound on this solvolysis reaction increases as the reaction temperature is lowered. Thus the sonochemical effect increases from 1.7 at 25°C to 20 at 10°C. This inverse relationship between temperature and ultrasonic effect is a common observation in sonochemistry. In simple terms the more vapour which enters the cavitation bubble the more of a cushion it will provide against violent collapse. Hence any reduction in... 

Atobe M, Sasahita M, Nonaka T (2000) Ultrason Sonochem, Ultrasonic Effects on Electroorganic Processes. Part 17. Product Selectivity Control in Cathodic Reduction of Acrylonitrile 7 103-107... 

Since ionic liquids have generally much higher viscosity, mass transport is quite slow as described before. This is a disadvantage for electrosynthesis in ionic liquids. However, it was found that electroreduction of N-methylphthalimide was promoted under ultrasonication resulting higher conversion and current efficiency as shown in Scheme 2 [13]. This is as due to facilitated mass transport of the substrate xmder ultrasonication. Similar but more pronounced ultrasonication effect was observed in electrochemical difluorination of ethyl a-(phenylthio)acetate in ionic liquid EtsN-SHF to provide the corresponding a,a-difluoro products [14]. 

Such a mass transfer promotion by ultrasonication provides an increase in the current efficiency for a variety of electrosyntheses. For example, Atobe et al. reported that a significant ultrasonic effect on the current... 

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