Radetzky: a new, large grazing incidence interferometer for large plane surface testing

2008 ◽  
Author(s):  
Emilio Molinari ◽  
Paolo Spanò ◽  
Giorgio Toso ◽  
Daniela Tresoldi ◽  
Roberto Biasi ◽  
...  
Keyword(s):  
Plane Surface ◽  
Grazing Incidence ◽  
Large Plane ◽  
Surface Testing

A Normal Flat Plate Close to a Large Plane Surface

1982 ◽  
Vol 33 (1) ◽  
pp. 90-104 ◽  
Author(s):  
K.W. Everitt
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Layer Thickness ◽  
Vortex Shedding ◽  
Boundary Layer Thickness ◽  
Plane Surface ◽  
Surface Boundary ◽  
Plate Height ◽  
Surface Boundary Layer ◽  
Large Plane

SummaryThe flow around a normal flat plate close to a large plane surface has been investigated for a range of boundary-layer thickness on the plane surface of 0.72 to 2.53 times the plate height, h. As the gap between the plate and the plane surface is reduced below about 0.55h vortex shedding from the plate is inhibited by the presence of the plane surface. Boundary layer thickness has little effect on the gap at which this occurs, but does affect the strength and frequency of vortex shedding at greater gaps. As the gap between the plate lower edge and the plane surface is decreased towards the critical value of 0.55h, both vortex strength and Strouhal number are more significantly affected when the approaching boundary layer is thin. It is not clear whether this is a result of shear or increased turbulent intensity.

scholarly journals The adsorption of iodine by potassium iodide

1933 ◽  
Vol 141 (843) ◽  
pp. 217-232 ◽  
Keyword(s):  
Experimental Work ◽  
Low Temperatures ◽  
Small Area ◽  
Capillary Condensation ◽  
Plane Surface ◽  
Previous Treatment ◽  
Monomolecular Layer ◽  
Apparent Area ◽  
Adsorption Of Gases ◽  
Large Plane

Opinion has been divided for some years as to whether the adsorption of a vapour on a solid surface is confined to a monomolecular layer until the vapour pressure reaches the saturation value, or whether multimolecular layers are formed. Experimental work has generally failed to provide an unequivocal answer to this point, often because the true area of the surface of the adsorbent could not be estimated. It is now recognized that the true area of a surface may be many times the apparent area, and the ratio of these will depend on the previous treatment of the surface. The position has been complicated further by the difficulty of determining the amount of adsorption on a small area of a plane surface when the adsorption is so small as to be undetectable without sensitive apparatus; consequently, the bulk of the experimental work has been carried out on finely divided adsorbents, of large surface. This breaking up of the adsorbent, whether accomplished by chemical or mechanical means, is bound to have an unpredictable effect on the ratio of the true to apparent area of the surface, as distinct from the purely geometrical multiplication. The use of porous or finely divided adsorbents may also introduce the additional complication of capillary condensation of vapours in the spaces between the particles. It is clear, as was first emphasized by Langmuir in 1918, that the investigation of adsorption on plane surfaces, using more delicate technique, is the first step towards a solution of the problem. Langmuir measured the adsorption of gases on large plane surfaces of mica, glass and platinum at low temperatures and pressures. He showed that the adsorption reached a maximum, which corresponded to slightly less than one complete monomolecular layer, and that the extent of adsorption was related to the pressure by an equation of the form x = abp /1 + ap where a and b are constants involving the condensation coefficient, the time of life of adsorbed molecules in the surface, and the number of “ adsorbing centres.”

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