Degree of roughness

Fig. 9. Number of cracks per mm vs percent strain in an alurnina—alurninum composite for different degrees of roughness where (0) represents the pohshed substrate (B), steep sided pits, 10 /cm and (A), gendy sloping pits, 10 /cm. ...

For opaque materials, the reflectance p is the complement of the absorptance. The directional distribution of the reflected radiation depends on the material, its degree of roughness or grain size, and, if a metal, its state of oxidation. Polished surfaces of homogeneous materials reflect speciilarly. In contrast, the intensity of the radiation reflected from a perfectly diffuse, or Lambert, surface is independent of direction. The directional distribution of reflectance of many oxidized metals, refractoiy materials, and natural products approximates that of a perfectly diffuse reflector. A better model, adequate for many calculational purposes, is achieved by assuming that the total reflectance p is the sum of diffuse and specular components p i and p. ... 

Type of Pipe Degree of Roughness Velocity ft/min Roughness Factor (Use as multiplier)... 

The corrosion process is modified by the physical state of the surface. Grinding and polishing processes, in particular, leave the structure in a more open state and with a degree of roughness and residual stress all can contribute to accelerated corrosion. 

In this work, lacnnarity analysis of TEM images of a previously synthesized hybrid organosilica material incorporating a biphenyl moiety was carried out. The results obtained snch as degree of connectedness of holes in sample material were correlated to the visnally observed degree of roughness of the materiaTs surface. 

Princen [57, 64, 82] and others [84] also noted the presence of wall-slip in rheological experiments on HIPEs and foams. However, instead of attempting to eliminate this phenomenon, Princen [64] employed it to examine the flow properties of the boundary layer between the bulk emulsion and the container walls, and demonstrated the existence of a wall-slip yield stress, below that of the bulk emulsion. This was attributed to roughness of the viscometer walls. Princen and Kiss [57], and others [85], have also showed that wall-slip could be eliminated, up to a certain finite stress value, by roughening the walls of the viscometer. Alternatively [82, 86], it was demonstrated that wall-slip can be corrected for and effectively removed from calculations. Thus, viscometers with smooth walls can be used. This is preferable, as the degree of roughness required to completely eradicate wall-slip is difficult to determine. 

Visually, all test sections appear to be performing satisfactorily. We evaluated the surface riding characteristics by use of the Mays Ride Meter which indicated that the various sections possess essentially the same degree of roughness. 

The degree of roughness or irregularity, i, is conventionally measured by dividing the actual true or contour area, Aj, of the surface by its projected area or outside geometric area, Ag ... 

The flow curves characterizing the extrusion of highly entangled polymer melts in conventional dies (metal, with any reasonable degree of roughness and having no special prior treatment) thus show that such flows are governed by ... 

Surfaces of materials possess different degrees of roughness depending on the way they are produced. When two solid surfaces are pressed together with a force acting normal to them, they make contact at the tips of the asperities in the two surfaces. In the case of soft metals and polymers, because of yielding, these points of contact form adhesive junctions. The minimum force required to slide one surface over the other is the force of friction F) and is given by (37)... 

A large body of literature is available on estimating friction loss for laminar and turbulent flow of Newtonian and non-Newtonian fluids in smooth pipes. For laminar flow past solid boundaries, surface roughness has no effect (at least for certain degrees of roughness) on the friction pressure drop of either Newtonian or non-Newtonian fluids. In turbulent flow, however, die nature... 

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