Local wetting

Fig. 7. SE images of a red sandstone (Wilstenzeller Buntsandstein) impregnated with potassium siliconate for comparison with the stone specimens from Pig. 6 diat ate treated with the more suitable silicones SMK. a Partly very thick silicone layer with poor local wetting (see white arrows) and homogeneously distributed precipitate of K2CO3. b Non-intact silicone coat on altered feldspar with fracture edge (see white arrows) white K2CO3 crystallites are heterogeneously distributed.

Local wetting and coming back to the problem location later can sometimes overcome these problems. 

Shredders are usually jacketed to permit cooling or heating as required. Mechanical action and the heat involved will cause depolymerization, which affects subsequent aging requirements. It is important to avoid excessive drying, carbonation, or localized wetting from condensation of the crumb within the shredder. Carbonation, due to reaction of CO2 from air with the alkali on the crumb, forms sodium carbonate, which blocks access of CS2 to the... 

Yamamura K, Mitani T (2008) Etching characteristics of local wet etching of silicon in HF/HNO3 mixtures. Surf Interface Anal 40 1011-1013... 

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 ... 

The wetting efficiency f is quite easily described by assuming a complete local wetting when the liquid flow through the pore is different from zero. 

Light-localized, wet processing of semiconductors which is not photoelectrochemical in nature is also known. Localized surface heating can reduce the overpotential for electroplating (2) or accelerate etching, for example. In addition, reactive intermediates can be produced by photolysis of electrolyte species (e.g., Brg), which then go on to react chemicaiiy with the semiconductor surface (3). These nonphotoelectro-chemicai approaches will not be dealt with further in this chapter. 

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