“…Modiÿcations to the operation can include using two or more cyclones in parallel or in series (Grane, Barbaris, & Behrouzi, 1992;Smith, Cushing, & Wilson, 1982;Smith & Wilson, 1979), and electrifying the cyclone to set up a radial potential gradient, which would augment the collecting force (Cheng & Wang, 1999;Dietz, 1982;Gradon, Luckner, Podgorski, & Werterjuk, 1998;Lim, Lee, & Kuhlman, 2001;Plucinski, Gradon, & Nowicki, 1989). Dietz (1982) enhanced the cyclone separator using an electrical force, and Plucinski et al (1989) and Gradon et al (1998) applied high voltages to the vortex ÿnder to form the electric ÿeld.…”