Electrostatic assist

The development of the novel Davy-McKee combined mixer—settler (CMS) has been described (121). It consists of a single vessel (Fig. 13d) in which three 2ones coexist under operating conditions. A detailed description of units used for uranium recovery has been reported (122), and the units have also been studied at the laboratory scale (123). AppHcation of the Davy combined mixer electrostatically assisted settler (CMAS) to copper stripping from an organic solvent extraction solution has been reported (124). 

Rotary atomisation produces the most uniform atomisation of any of the aforementioned techniques, and produces the smallest maximum particle sise. It is almost always used with electrostatics and at lower rotational speeds the electrostatics assist the atomisation. At higher rotational speeds the atomisation is principally mechanical in nature and does not depend on the electrical properties of the coating material. If the viscosity of a coating material is sufficiendy low that it can be deUvered to a rotary atomiser, the material can generally be atomised. The prime mover is usually an ak-driven turbine and, provided that the turbine has the requked power to accelerate the material to the angular velocity, Hquid-dow rates of up to 1000 cm /min can be atomised using an 8-cm diameter beU. 

Hsu CS and Hwang BH. Microstructure and properties of the La06Sr04Co02Fe08O3 cathodes prepared by electrostatic-assisted ultrasonic spray pyrolysis method. J. Electrochem. Soc. 2006 153 A1478-A1483. 

Schreiber, G. andFersht, A.R. (1994) Rapid, electrostatically assisted association of proteins, J. Mol. Biol. 238, 415-436. 

This paper gives an outline of one of the most successful applications of electrostatic techniques in an existing production process, namely, the electrostatic assist process for ink transfer in gravure printing. 

The electrostatic assist process was developed to overcome a specific print defect which had plagued printers and paper makers for years, namely, skipped dots. 

Figure I. Comparison of a section of a catalog page with electrostatic assist on (left), and electrostatic assist off (right).

Elektrostatisch unterstiitztes Mischen feinkomiger Partikel (Electrostatically assisted mixing of finely dispersed particles)... 

Intramolecular general acid catalysis concerted with intramolecular nucleophilic (or electrostatic) assistance... 

G. Arena, A. Casnati, A. Contino, F. G. GuUno, D. Sciotto, R. Ungaro, Entropic origin of the sulfonate groups electrostatic assistance in the complexation of quaternary ammonium cations by water soluble cahx[4]arenes, J. Chem. Soc., Perkin Trans. 2, 2000, 419-423. 

In purely electrostatic spraying, the paint is atomized solely by electrostatic forces. In electrostatically assisted spraying, atomization takes place by the methods described in Section 8.3.1, with simultaneous or subsequent electrical charging. 

Electrostatically assisted atomization methods are more versatile than purely electrostatic methods because atomization takes place mechanically. The electric field serves only to charge the paint material and to transport the charged droplets to the workpiece. The following systems are used ... 

Electrostatically assisted compressed air, airless, and aiimix atomization... 

Electrostatically assisted atomization guns (charging by means of needle-shaped electrodes arranged directly in or on the paint nozzle, voltage 50-100 kV). 

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