Roughness, and wetting

In conclusion, our investigations of rough stainless steel surfaces revealed that the surface roughness clearly influences the oleophilicity. This means there is a correlation between the roughness and wetting properties. 

Adhesion mechanisms in biology are diverse, and robust enough to function on rough and wet surfaces. However, bio-adhesion must be easily releasable when related to animal movement. 

The above inequality implies that the surface roughness enhances wetting whenever A/( 1) > 0 and is quite consistent with the experimentally determined Wenzel law [203]... 

It is roughly estimated that there are more than 1,200,000 water bodies in eastern North America that are currently affected by acid deposition. A subset of these lakes has been sampled since early 1980s in order to monitor the changes in lake water chemistry induced by the declining sulfur dioxide emissions and wet sulfate deposition... 

Roughness factor (r), 22 111 Roughness indexes, 15 203 Roughness ratio (=), 22 115 Roughness, surface wetting and, 22 110-113... 

V is cross-sectional mean velocity, v is kinematic viscosity, e is wall roughness, and D is pipC di IUCtel 4Rh. Rh is hydraulic radius, A/P, where A is cross-sectional area and P is wetted perimeter (Moody,... 

Oxidation behavior of the TiSi2 on silicon is the final concern.22 A good deal of surface and interfacial roughness was observed on the films that had been put down on silicon and wet oxidized for one hour at 800°C. The oxide layer was about 1800 A thick. Further study of the quality of the oxide layer will be necessary before this film can be considered for device applications. 

For this application, a rough and well-defined surface morphology is necessary. It is achieved by post-deposition wet-chemical etching (see [113] and Chaps. 6 and 8). The film thickness to be deposited is in the order of 1,000 nm and about 300 nm of layer thickness is removed by the wet-chemical etching procedure. 

At present, many authors I20-I26 follow another concept From the plot of pj p [M /t) versus the surface tension of the liquids, the geometric factor K is calculated for those liquids that should wet the solid completely. By inserting this K value and [t]/p- ] M2/t for these liquids into Eq. (13). their contact angles 0 are calculated and used for the interpretation of the solid-vapor surface tension of the porous material. This procedure is dubious, because it can be expected that the contact angles, calculated from the Washburn equation, are affected by roughness and porosity. If we apply this procedure to the PTFE powder for hexadecane, a contact tingle 0 = 88 would be obtained. However, it is well known that the contact angle of hexadecane on a flat and smooth... 

The determination of the channel dimensions was carried out using scanning electron microscopy. The hydraulic diameter was calculated with the total flow area and wet perimeter measured from electron microscope images in order to take into account the effect of the first and last channels which are rounded. Roughness measurements were also carried-out. 

The interface boundary inside the chaimel is shown on figures 4 and 5 as a function of the liquid Reynolds number. At large liquid flow rate the considerable part of the liquid flows in the corners and the film is thinned both on the long and short sides of the channel. This enhances the heat transfer in comparison with uniform film. At small liquid Reynolds numbers the minimum film thickness becomes the same as the wall roughness and film rupture occurs leading to stable rivulet flow. Dry areas exist on the wall, which are not wetted by liquid. This reduces the heat transfer. The... 

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