Particles blade-shaped

The dispersion blade in Fig. 18-49 was developed to provide higher compressive shear than the standard sigma blade. The blade shape forces material against the trough surface. The compressive action is especially good for dispersing fine particles in a viscous material. Rubbery materials have a tendency to ride the blades, and a dispersion blade is frequently used to keep the material in the mixing zone. 

As Langmuir s paper will be considered separately and the paper by Bergmann c.s. runs on somewhat different lines (explanation of the formation of Schiller layers in sols of blade-shaped particles), we shall here summarize only briefly the way in which the force equation is involved inr Derjaguin s theory of stability. A drawback of this Work is that the double layer repulsion i only considered in the linear approximation (v fe kT), excluding all possibility... 

Figure 13.3 Scanning electron micrograph showing the microstructure of a glass-ceramic material. The long, acicular, blade-shape particles yield a material with unusual strength and toughness. 40,000X.

In the foregoing subsection it has been tacitly assmned that the particles are regular in shape (spherical, cubical or the like). In fact of course, they are often more irregular, and especially if their dimensions are much larger in one or two directions than in the other, the rod-shaped or blade-shaped particles give rise to interesting phenomena. 

In most cases hydrophobic sols are NEWTONian liquids with a viscosity only slightly deviating from that of the dispersion medium. In the flocculated state more or less clear indications of non-NEWTONian behaviour, especially the presence of a yield value, may be detected. This is most evident for sols containing blade-shaped or rodshaped particles like iron oxide or vanadium pentoxide. When these sols are not too dilute and electrolyte is added to them in quantities insufficient to obtain flocculationp gel formation is often observed. The who.le mass becomes solid, probably becauste by partial flocculation the particles of the sol form a loose network, in the meshes of which the intermiccllar liquid is retained. 

Heller and Bernal and Fankdchen have pointed out the possibility of explaining gel-formation in sols with rod-shaped or blade-shaped particles by assuming a local orientation and fixation of particles by long range forces, the whole system being solidified by a network of chains of particles thus held more or less rigidly near to each other. Fig. (27). 

Again in accordance with our picture is the ease of repepti2 ation of cven very small day particles (equivalent diameter 20 m x) because these are in reality blade-shaped and therefore may experience a comparatively large hydrodynamic force and a small attraction. 

Another advantage of the radial reacrion turbine is that it can be designed to accept condensation in any amount without efficiency deterioration or erosion. This is possible because there are two forces acring on suspended fog particles, the deceleration force and the centrifugal force, and these two forces can be balanced against each other to prevent the droplets from impinging on specially shaped blades. The process is expl ned as follows ... 

To use turboexpanders for condensing streams, the rotor blades must be shaped so that their walls are parallel at every point to the vector resultant of the forces acting on suspended fog droplets (or dust particles). The suspended fog particles are thus unable to drift toward the walls. Walls would otherwise present a point of collection, interfering with performance and eroding the blades. Hundreds of turboexpanders are in successful operation involving condensing liquids. 

Gels of various particle sizes can be made by varying the stirring rate, the shape of the stir blades used, the concentration of the suspending agents, and, to a lesser degree, the ratio of the continuous water phase to the discontinuous organic phase. 

Blade Long, thin, and flat particle, which can also be referred to as being lath-shaped. 

Suspensions or dispersions of particles in a liquid medium are ubiquitous. Blood, paint, ink, and cement are examples that hint at the diversity and technological importance of suspensions. Suspensions include drilling muds, foodstuffs, pharmaceuticals, ointments and cremes, and abrasive cleansers and are precursors of many manufactured goods, such as composites and ceramics. Control of the structure and flow properties of such suspensions is often vital to the commercial success of the product or of its manufacture. For example, in consumer products, such as toothpaste, the rheology of the suspension can often determine consumer satisfaction. In ceramic processing, dense suspensions are sometimes molded (Lange 1989) and then dried and sintered or fired into optical components, porcelin insulators, turbine blades, fuel cells, and bricks (Rice 1990 Simon 1993). Crucial to the success of the processing is the ability to transform a liquid, moldable suspension into a solid-like one that retains its shape when removed from the mold. These examples could be multiplied many times over. 

Detasheet can easily be cut to shape using a fixed blade knife or type metal die. on a tion-metallic anvil. Cutting with ordinary scissors is not rec-commended because any situation subjecting small particles of e l to a grinding or shearing action should be avoided. Detasheet has been designated by the ICC as Class A Explosive and the rules and regulations for transpoitation of explosives ( CFR 71-90) apply... 

Variations of the simple disc shape include (1) an outer reroll ring which allows granules to be simultaneously coated or densified without further growth, (2) multistepped sidewalls, and (3) a pan in the form of a truncated cone (Capes, Particle Size Enlargement, Elsevier, 1980). Discs in the form of deep pans running close to horizontal with internal blades and choppers are also available, as a hybrid disc-mixer system. 

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