Capillarity wettability

In the United States, a number of physical tests are performed on silicon carbide using standard AGA-approved methods, including particle size (sieve) analysis, bulk density, capillarity (wettability), friability, and sedimentation. Specifications for particle size depend on the use for example, coated abrasive requirements (134) are different from the requirements for general industrial abrasives. In Europe and Japan, requirements are again set by ISO and JSA, respectively. Standards for industrial grain are approximately the same as in the United States, but sizing standards are different for both coated... 

The next two chapters are concerned with wetting and capillarity. Wetting phenomena are still poorly understood contact angles, for example, are simply an empirical parameter to quantify wettability. Chapter 6 reviews the use of scanning polarization force... 

In methods where flow is not confined by a column (such as paper and thin-layer chromatography), flow is usually driven by capillarity—the tendency of a liquid to flow into vacant capillaries having a wettable surface. Flow by capillarity will be discussed in Section 4.7. 

Solid-liquid Wettability Sol, gel, colloidal suspension, solid emulsion, wetting, spreading, surface tension, friction, lubrication, diffusion, pervaporation, capillarity, electrochemistry, galvanic effects, corrosion, cleaning, filtration, ion electromigration, optical properties, charge transfer, nucleation and growth... 

To describe wettability in a porous reservoir rock requires inclusion of both the fluid surface interaction and curvature of pore walls. Both are responsible for the capillary rise seen in porous media. The fundamental equation of capillarity is given by the equation of Young and Laplace [2]... 

Effect of wettability. Our attention to the effect of curvature on the saturation pressure was directed to a bubble or, equivalently, when the liquid wets the solid surface. This is often true in hydrocarbon reservoirs in which gas is the nonwetting phase and oil is the wetting phase. However, in some other systems, gas may be the wetting phase and oil (or the liquid) may be the nonwetting phase. Even in rocks, liquid mercury is the nonwetting phase and air is the wetting phase. In such cases, the Young-Laplace equation of capillarity for a tube should be written as... 

Several aspects must be taken into account concerning rehydration (Bimbenet ef al., 2002). For powders, the dispersion in water depends on the size (agglomeration favors the dispersion), the composition (surface wettability i.e., composition in fat and non-soluble components), or the sinkability linked with structure (porosity, capillarity), leading to formation of lumps or precipitates. 

The phenomena of capillary penetration of liquids into pore spaces filled with a fluid are related to the rise of liquids in capillary tubes where the flow is driven by interfacial pressure differences, as described by the Laplace equation of capillarity (equation (7.1)). The magnitude of the pressure difference across each liquid-fluid interface (meniscus) depends on the local curvature which is determined by the local wetting properties and pore geometry. In a cylindrical capillary, where the capillary wall is completely wettable by the liquid, the liquid-vapour interface can be assumed to be a hemisphere and = R2 = r r << a, cf. equation (7.48) below), where r is the capillary radius. Then, equation (7.1) becomes particularly simple and reduces to the following ... 

As discussed above, increases in wettability have been one of the primary and well-recognized surface effects obtained on textiles with plasma systems which utilize oxygen, air, and ammonia plasmas. Other recognized benefits are enhancements in surface desizing and capillarity of natural textile fibers such as wool and cotton. Particular to the hydrophobic properties of wool fiber surfaces, we have summarized that these can be transitioned to hydrophilic to obtain a reduced felting effect. However, if there is interest in moving toward an inverse effect, hydrophobic properties, as observed on cotton fabrics, can be also induced with prescriptions of type and proportions of gas chemistries used in the plasma reaction [33]. 

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