Influence of Surface Roughness

Another example of models that use the approximation of real surface profiles by spherical asperities is that of Rumpf [866], where the adhesion between a sphere with radius Rp and a rough surface with asperities of radius due to van der Waals interaction is given as 

A different approach to the characterization of surface roughness uses fractals. The basic idea was introduced by Archard [869] even before the term fractals was coined. Majumdar and Bhushan [870] noticed that surfaces often exhibit roughness on different length scales and could best be described as self-affine. Corresponding theories that hnk the fiactal dimension of the surface with the dependence of true contact area on applied load have been developed recently by the groups of Persson 

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Endoh, M., Influence of Surface Roughness of Mild Steel Substrate on Adhesive Strength of Zinc Sprayed Coatings . Proc. 8th Int. Thermal Spray. Conf., American Welding Society, pp. 492-502 (1976)... 

Experiments were conducted with air through micro-channel A = 319 (friction factor. The relative surface roughness was low k /H = 0.001) and Kn < 0.001, thus the experiments were effectively isolated from the influence of surface roughness and rarefaction. The local friction factor is plotted versus Ma in Fig. 2.25 for air. The experimental A increases about 8% above the theoretical A as Ma increases to 0.35. 

Fig. 2.26 Influence of surface roughness on friction factor. Reprinted from Turner et al. (2004) with permission...

The influence of surface roughness, surface diffusion of metal atoms, and exchange current density of the Cd(II)/Cd... 

A useful discussion of incompressible fluid flow in pipes and the influence of surface roughness and friction factors on pumping is found in Perry s Chemical Engineer s Handbook (49). 

With respect to the preparation of die surface, a measurement of a surface property is obviously only as good as the preparation of the surface on which the measurement is made. Ideally one would desire to have a surface which was atomically flat on a crystallographically perfect and chemically pure crystal. After reliable information had been obtained chi such ideal surfaces, it would then be necessary to determine the influence of surface roughness, of impurities, and of crystal imperfections of various kinds on the oxidation process. Most of the measurements to be described in this paper, however, have been made on surfaces which were prepared by the best methods available at this time. A convenient method of determining the important faces of a metal for detailed study involves the initial use of the specimen in the form of a sphere exposing all possible crystal faces such methods have been previously described, it should be emphasized that much additional work... 

Daikhin, L. Urbakh, M., Influence of surface roughness on the quartz crystal microbalance response in a solution new configuration for qcm studies, Faraday Discuss. 1997,107, 27-38. 

Influence of Surface Roughness on Maximally Expected Strength... 

Figure 66(a) describes the influence of surface roughness, represented by r (abscissa), on the attraction force A for different adhesion mechanisms. 

S. Anderson and E. Salas-Russo, The influence of surface roughness and oil viscosity on the transition in mixed lubricated sliding steel contacts, Wear, 174, 71-79, 1994. 

Fig. 10.6 Model sketches depicting the influence of surface roughness on the approach of particles to each other (left) and wetting (liquid bridge formation, right). The crosshatched area is the actual...

M. Quirynen, C.M.L. Bollen, The influence of surface roughness and surface-free energy on supra- and subgingival plaque formation in man. A review of the literature, J. Clin. Periodontol. 22 (1995) 1-14. 

K. Range, F. Feuillebois Influence of surface roughness on liquid drop impact, J. Colloid Interface Sci., 203,16-30 (1998). 

Kabeya H, Kannokor AK, Kamata Y. Influence of surface roughness of woven geotextiles on interfacial Motional behaviom-evaluation through model experiments. Textile Research J 1993 63 604-10. 

As has been pointed out several times, the surface of paper is far from being a smooth ideal surface. This has great consequences on the wetting behaviour that is observed. For random rough surfaces, the influence of surface roughness can be described by using Wenzel s equation ... 

Lundgren, A. K., Lundgren, D., Wennerberg, A., Hammerle, C. H., and Nyman, S. (1999), Influence of surface roughness of barrier walls on guided bone augmentation Experimental study in rabbits, Clin. Implant Dent. Relat. Res. l(l) 41-8. 

Tanaka M, Komagata M, Tsukada M, Kamiya H. Fractal analysis of the influence of surface roughness of toner particles on their flow properties and adhesion behavior. Powder Technol 2008 186 1-8. 

Apparently N. A. Fuks [2] is correct in that the quantity r in Eq. (1.39) must not be considered the particle radius, but rather the radius of those sub-microscopic projections through which actual contact occurs between the particle and surface. Hence, in Chapter V we will be examining the influence of surface roughness and radius of curvature of the contacting bodies on the magnitude of adhesion. 

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