Surface topography, mechanical effect

Surface topography can affect the local wind patterns one example is the onshore and offshore breeze, and another example is the heat island over large urban areas. Another manmade effect is the generation of mechanical turbulence caused by the nonuniform height of buildings in a city. We will discuss this effect in more depth later on. 

The mechanical effect of surface topography also exerts an influence on the interphase. The anodized oxides are the best examples of this feature. The oxides may be formed by a porous network 60 nm thick composed of pores close packed of 20 nm in diameter. The epoxy can penetrate into this structure to the bottom of the pores (Fig. 9). The effect is of a mechanical interlocking of the epoxy with the oxide which... 

Thin solid films of polymeric materials used in various microelectronic applications are usually commercially produced the spin coating deposition (SCD) process. This paper reports on a comprehensive theoretical study of the fundamental physical mechanisms of polymer thin film formation onto substrates by the SCD process. A mathematical model was used to predict the film thickness and film thickness uniformity as well as the effects of rheological properties, solvent evaporation, substrate surface topography and planarization phenomena. A theoretical expression is shown to provide a universal dimensionless correlation of dry film thickness data in terms of initial viscosity, angular speed, initial volume dispensed, time and two solvent evaporation parameters. 

Wang C, Sherman P, Chandra A. A stochastic model for the effects of pad surface topography evolution on material removal rate decay in chemical mechanical planarization (CMP). IEEE Trans Semicond Manuf 2005 I8(4) 695-708. 

The mechanical interlocking is a topography-based effect and the surface prepa-ration/treatment is an important factor in effectiveness of mechanical interlocking. When the composite and its interface are strained, the shapes of certain surface irregularities may increase the local stress concentrations. Wood is one of the porous materials which have tortuous pore networks. Mechanical interlocking is improved by permeating the adhesive/matrix into these networks [82]. 

Furthermore, neither PGA nor PLA possess intrinsic bioactivity. Cellular responses to implants of these polymers are mediated mostly by surface adsorbed proteins, surface topography, and local acidity. Crystallinity seems to be another parameter affecting cell adhesion on PLA/PGA polymers. The effects are believed to be a result of differences in protein conformation stemming from variations in binding to amorphous versus crystalline polymer surfaces. The chirality of crystalline regions may also play a role in controlling cellular response, but the detailed mechanisms of these effects are not fully understood. 

An objective comparison of the abrasion resistance of superhydrophobic surfaces has been hampered by the lack of a single, standardized test method. Likewise, no single measure has been used for characterizing the effect of wear. Moreover, all these different approaches induce very diverse surface topography modifications but at the same time all of them are referred as mechanical durability tests. This is very confusing for someone who wants to evaluate how durable is one surface compared to the other. Generally, abrasion resistance is most directly and commonly measured using linear shear abrasion. In this form, shear stress arises from the force vector component parallel to the cross section of the material. The most common approach, based on the number of published papers, for the evaluation of the mechanical durability of liquid repellent surfaces is... 

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