Wetting temperature

In order to demonstrate that the systems in question exhibit nonzero wetting temperature, we have displayed the results of calculations for one of the systems (with =1 at T = 0.7). Fig. 12 testifies that only a thin (monolayer) film develops even at densities extremely close to the bulk coexistence density (p/,(T — 0.7) — 0.001 664). In Fig. 13(a) we show the density profiles obtained at temperature 0.9 evaluated for = 7. Part (b) of this figure presents the fraction of nonassociated particles, x( )- We... 

Numerical solution of Eq. (51) was carried out for a nonlocal effective Hamiltonian as well as for the approximated local Hamiltonian obtained by applying a gradient expansion. It was demonstrated that the nonlocal effective Hamiltonian represents quite well the lateral variation of the film density distribution. The results obtained showed also that the film behavior on the inhomogeneous substrate depends crucially on the temperature regime. Note that the film exhibits different wetting temperatures on both parts of the surface. For chemical potential below the bulk coexistence value the film thickness on both parts of the surface tends to appropriate assymptotic values at x cx) and obeys the power law x. Such a behavior of the film thickness is a consequence of van der Waals tails. The above result is valid when both parts of the surface exhibit either continuous (critical) or first-order wetting. 

When the temperature lies in between the wetting temperatures of both substrates, then one substrate is wet and the film thickness on that part diverges when the distance from the boundary between different substrates increases. This divergence is found to be represented by a power law x for... 

In the semicontinuous pad roll process, after impregnation with the pad liquor, the material is batched up and stored in an air-free steam chamber (dry and wet temperature ca. 98°C) where it is rotated slowly for about 1 h. By this procedure, the dye is almost completely fixed. Excellent penetration is obtained. 

Transmission Electron Microscopy 1 glass point temperature 2.2.1 pre-wetting critical point 3.1 reference temperature 2.2.3,3.1.2.3,3.1.2.5 wetting temperature 3.1 ... 

This standard considers the stability of plastics when they are exposed outdoors. The relative durability of plastics in outdoor use can be very different depending on the location of the exposure because of the differences in UV radiation, wetness, temperature, pollutants (acid rains, for example), and many other factors. Hence, exposure in several locations with different climates that represent a broad range of anticipated service conditions are recommended by this ASTM. Still, because of year-to-year climatological variations, resnlts of exposure in 1 year cannot be used to predict the absolute rate at which a material degrades. Therefore, several years of repeated exposure to get an average test result for a given location is recommended. 

Figure 10-5. Effect of concentration on critical wetting temperature for oleophobic films on platinum. (a) n-Octadecyl compounds in cetane. (b) n-Eiscosyl and n-octadecyl acids and alcohols in cetane. (c) n-Octadecyl acid and alcohol in cetane and in dicyclohexyl. Data by Bigelow, Glass and Zisman [181.

The wetting temperature is determined as the lowest binder temperature used when spreading the chippings on the plate, which results in 90% of the chippings being stained by the binder. 

More information about the test and the way to determine wetting temperature and fragility temperature is given in CEN EN 12697-3. 

Below a still lower temperature, the critical wetting temperature, only a thin adsorbed film exists for b < b° because the gradient energy is so high that development of thicker films is energetically unfavorable. For densities above a finite contact angle exists where liquid and vapor phases meet the surface. Thus... 

Fusion point is the temperature at which, in a specified set of conditions, particles of polyvinyl chloride (PVC) resin are first made transparent, gelled, or dissolved by a plasticizer. The other relevant terms are clear point, solid gel transition temperature , and apparent wetting temperature. The fusion point provides a numerical indication of the compatibility of the plasticizer with the PVC resin. 

Atmospheric—Atmospheric corrosion is responsible for a large fraction of the total corrosion in the world. Factors that affect the atmospheric corrosion of materials in a marine environment are the time of wetness, temperature, material, atmospheric contaminants and pollutants, solar radiation, composition of the corrosion products, wind velocity, and biological species [fO]. Atmospheric corrosion of a passive alloy tends to be localized. For electrochemical processes related to corrosion to occur, an electrolyte must be present to allow current to pass via diffusion and electrochemical migration of cations and anions. Seawater is a very conductive electrolyte. The severity of corrosion in an atmospheric environment is related to the time of wetness during which electrochemical processes and corrosion take place. There is also a direct relationship between atmospheric salt content and measured corrosion rates [/O]. 

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