Rugosity factor

Wenzel [68] considered rough surfaces and supposed that the true solid surface area could be related to the nominal area by a rugosity factor , r- ... 

Factors affecting the mix of active ingredients and excipients should be discussed. These should include particle size and shape, rugosity, charge, flow properties, and water content. Since the dose delivery for these products is dependent on air flow characteristics, an attempt should be made to establish an in vivo-in vitro correlation. 

Perimeter, Hausner shape factors, Martins diameter, Feret diameter, two dimensional sphericity, rugosity. 

This section will discuss some of the commonly used and cited shape factors in the pharmaceutical industry the shape factors discussed in this section are Wadelfs true sphericity and circularity, rugosity coefficient, correction factor, Dallavalle s shape factor, Heywood s shape factor, Schneiderhohn aspect ratio, one plane critical stability (OPCS), and Podczeck s two- and three-dimensional factor. There are also many other shape factors but they are beyond the scope of this chapter (11,14,26-31). 

SPHERICITY is the ratio of the surface area of a sphere having the same volume as the particle, to the actual particle surface area the reciprocal is known as the coefficient of rugosity or angularity. It can be shown that sphericity is also equal to the ratio of the surface-volume diameter to the equivalent volume diameter this makes sphericity a useful conversion factor between... 

Figure 2 shows a small portion of the interfacial region as a liquid (adhesive) is brought into contact with a solid substrate. Certain factors hinder bond formation, whereas others promote it. Barriers include (1) surface rugosity, (2) species adsorbed on the solid before bonding, (3) air entrapped in micropockets between the liquid and solid, (4) surface tension of the liquid and its bulk viscosity arising from cohesive forces among liquid molecules. Fac-... 

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