Films black

Exerowa and co-workers [201] suggest that surfactant association initiates black film formation the growth of a black film is discussed theoretically by de Gennes [202]. A characteristic of thin films important for foam stability, their permeability to gas, has been studied in some depth by Platikanov and co-workers [203, 204]. A review of the stability and permeability of amphiphile films is available [205]. 

Make an estimate of the hydrostatic pressure that might be present in the Plateau border formed by the meeting of three thin black films. Make the assumptions of your calculation clear. 

As a point of interest, it is possible to form very thin films or membranes in water, that is, to have the water-film-water system. Thus a solution of lipid can be stretched on an underwater wire frame and, on thinning, the film goes through a succession of interference colors and may end up as a black film of 60-90 A thickness [109]. The situation is reminiscent of soap films in air (see Section XIV-9) it also represents a potentially important modeling of biological membranes. A theoretical model has been discussed by Good [110]. 

Without intervention, this process would continue until all the Ag had been reduced, giving a completely black film. To prevent this, developing is stopped after an appropriate time, and the film is treated with an... 

New Substance Notification (NSN) regulations, 78 542 News vendor problem, 26 1026—1028 Newton Black films, 72 5 Newtonian behavior... 

Lead (I) suhoxide (Pb O) is the thin black film that forms naturally on a freshly cut piece of lead and that retards further oxidation. 

D. Exerowa, D. Kashiev, and D. Platrkanov Structural Properties of Soap Black Films Investigated by X-Ray Reflectivity. Adv. Colloid Interface Sci. 40, 201 (1992). 

P. Poulin, F. Nallet, B. Cabane, and J. Bibette Evidence for Newton Black Films Between Adhesive Emulsion Droplets. Phys. Rev. Lett. 77, 3248 (1996). 

As for cobalt (see earlier), an early study of the coloration of metals by immersion in boiling metal salt-thiosulphate solutions resulted in coloration of the metals [2]. Also as for cobalt, a single experiment by the author repeating (similar, not necessarily identical conditions) this experiment, only on glass, rather than on metals which might be colored by the thiosulphate alone, resulted in a black film on the glass. 

The Subozide of Silver—Ag, 0—was first obtained by Faraday, by exposing an ammoniacal solution of the protoxide to the action of air. It separates in the form of a black film. 

TARNISH. A reaction that occurs readily at room temperature between metallic silver and sulfur in any form. The well-known black film that appears on the silverware results from reaction between atmospheric sulfur dioxide and metallic silver, forming silver sulfide. It is easily removable with a cleaning compound and is not a true form of corrosion. Plating with a mixture of silver and indium will increase tarnish resistance. Gold will also tarnish in the presence of a high concentration of sulfur in the environment... 

When two emulsion drops or foam bubbles approach each other, they hydrodynamically interact which generally results in the formation of a dimple [10,11]. After the dimple moves out, a thick lamella with parallel interfaces forms. If the continuous phase (i.e., the film phase) contains only surface active components at relatively low concentrations (not more than a few times their critical micellar concentration), the thick lamella thins on continually (see Fig. 6, left side). During continuous thinning, the film generally reaches a critical thickness where it either ruptures or black spots appear in it and then, by the expansion of these black spots, it transforms into a very thin film, which is either a common black (10-30 nm) or a Newton black film (5-10 nm). The thickness of the common black film depends on the capillary pressure and salt concentration [8]. This film drainage mechanism has been studied by several researchers [8,10-12] and it has been found that the classical DLVO theory of dispersion stability [13,14] can be qualitatively applied to it by taking into account the electrostatic, van der Waals and steric interactions between the film interfaces [8]. 

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