Large disk-shaped particle

Ferroelectric fluid phases have also been observed in simulations of disk-shaped particles with embedded dipole moments along the symmetry axis [ 147,148] (see Sect. 4) and in a dipolar hard sphere model carrying two parallel dipole moments displaced equally from the sphere centre [ 149]. In the latter model antiferroelectric arrangement of the particles is, however, equally preferred at sufficiently large separations (0.3a) of the two dipole moments. 

Particle shape is also important. Disk-shaped as well as cylindrical-shaped conductors have a high response because large induced current loops are formed. Small randomly shaped conductors, such as those present in cmshed slag, also respond favorably. Sphere-shaped particles generate small-current loops, however, and do not have a high response. Multiple-current loops occur in conductors that have irregular bends, producing counteractive forces that tend to nullify each other. 

When the solids and the density difference is small and the flow volume is large, disk nozzle centrifuges are often the best means to accomphsh the ptuification. The separation, which takes place within the rotor of a disk nozzle centrifuge, is effected by the G force, the rising rate of the Uquid (related to the feed flow) and the separation area provided by a set of conical, close-spaced disks as well as the process factors of fluid viscosity, particle size, shape, and density. In addition, the design of the equipment must allow for the quantity of solids to he handled, the flow characteristics of the slurry, and other practical engineering considerations. 

Spheroids are of special interest, since they represent the shape of such naturally occurring particles as large hailstones (C2, L2, R4) and water-worn gravel or pebbles. The shape is also described in a relatively simple coordinate system. A number of workers have therefore examined rigid spheroids. Disks are obtained in the limit for oblate spheroids as E 0. The sphere is a special case where E = I. Throughout the following discussion. Re is based on the equatorial diameter d = 2a (Fig. 4.2). 

What are the physical properties of the solid and liquid phases present The degree of difficulty in solid suspension depends on several properties of the fluid and solid particles discussed in Section 10-2. The properties of interest include the relative density of the solid and liquid phases, the viscosity of the liquid, the wetting characteristics of the solid, the shape of the solid particles, and the mass or volume ratio of solids to liquid. Large and dense solids are more difficult to suspend than small light ones spherical particles are also more difficult to suspend than thin flat disks. The impact of these properties on solid-liquid mixing mnst be studied and understood early in process research and development. 

Colloidal particles (or droplets) are not always spherical. They can have various shapes (e.g. spherical and rod- or disk-like), as shown in Figure 1.4. Proteinic and polymeric molecules are usually large... 

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