Wetting additive effect

Since drying occurs simultaneously with wetting, the effect of diy-ing can substantially modify the expected impacd of a given process variable and this should not be overlooked. In addition, simultaneously drying often implies that the dynamics of wetting are far more important than the extent. 

Formations can be oil wet or water wet. The fluid filtrate depends on what is the continuous phase of the completion fluid. Thus the formation wettability can be reduced by wettability charge. This effect can be controlled either by proper fluid selection or by treatment with water wetting additives. 

Johnson et al. [27] report that polysulfone and poly(vinyl acetate) show enhanced low-temperature -loss transitions in proportion to the unclustered water. Clustered water in poly(vinyl acetate) has no effect on Tg, although shifts with increasing amount of unclustered water. Fuzek [3T] found that water absorbed by synthetic fibers and silk at room temperature and 65% RH substantially lowers Tq s, the effect being reflected in several different fiber properties. Wet soaking has an additional effect. 

The most common cause of sheet defects is bacterial/fungal material. This can be reduced by determining the source - from an additive make-up system, building up in the stock system or the wet-end. Effective treatment needs to be installed to minimise the problem. 

When the extent of carbonation is large, it may be necessary to remove a large amount of mechanically sound concrete. In order to avoid this expensive and undesirable operation, other methods have been developed that are aimed to reaUca-Hze the original concrete. An additional benefit of this method is that the thickness and/or density of the concrete cover is increased. This is beneficial in that it reduces wetting/drying effects at the steel. 

The most common acid solvent is inhibited muriatic acid. It is inhibited, as all acids solvents must be, to reduce chemical attack on metal surfaces to an acceptable level. Muriatic acid is cheap and effective. It forms reaction products that are generally water-soluble and so are removed in the used solvent. Sulfuric acid is seldom used because of its insoluble reaction products. Nitric acid cannot be prevented from attacking carbon steels or copper alloys. It has certain special applications where the substrate metal is stainless steel or aluminum. Of special interest for small-scale maintenance cleaning by plant personnel is sulfamic acid, mainly because it is a dry solid product that is safely to handle. It has acid properties only after it is dissolved in water. Solid inhibitors and wetting additives can be premixed into the packaged product. 

Method of Binder Incorporation. PVP can be incorporated in the granulation either by dry or by wet addition methods. The method of binder incorporation affects the granule s properties through its effect on binder dissolution and... 

Polymer Concentration. The effect of cellulosic polymer concentration on granule properties is dependent on their method of addition. In the wet addition method, increasing the concentration of HPC, different viscosity grades of HPMC and MC in lactose-cornstarch-microcrystalline cellulose systems increases the percentage of binder-rich oversize granules (61). The effect can be attributed to the increase in binder solution viscosity and heterogenous binder distribution. 

Solsperse 2400 (Zeneca) is a polymeric dispersant. Levelling and wetting additives improve the film appearance. Bentonite is added to prevent settling of the pigment. Fluorad FC-430 reduces cratering but can have a negative effect on recoatability. 

Thick insert (> 1/3 of the cavity thickness) or very thin plastic layer will cause a weak adhesion. This phenomenon can be explained so, that aluminum insert is effectively a heat sink that cools the melt and limits the penetration of melt to its microcavities. After a certain thickness value saturation penetration is reached and no additional effect can be obtained by decreasing the insert thickness. When the heat capacity of insert is low enough the viscosity of plastic does not decrease substantially and a good wetting of the microcavities is achieved. 

It was pointed out in Section XIII-4A that if the contact angle between a solid particle and two liquid phases is finite, a stable position for the particle is at the liquid-liquid interface. Coalescence is inhibited because it takes work to displace the particle from the interface. In addition, one can account for the type of emulsion that is formed, 0/W or W/O, simply in terms of the contact angle value. As illustrated in Fig. XIV-7, the bulk of the particle will lie in that liquid that most nearly wets it, and by what seems to be a correct application of the early oriented wedge" principle (see Ref. 48), this liquid should then constitute the outer phase. Furthermore, the action of surfactants should be predictable in terms of their effect on the contact angle. This was, indeed, found to be the case in a study by Schulman and Leja [49] on the stabilization of emulsions by barium sulfate. 

Humidification. For wiater operation, or for special process requirements, humidification maybe required (see Simultaneous HEAT and mass transfer). Humidification can be effected by an air washer which employs direct water sprays (see Evaporation). Regulation is maintained by cycling the water sprays or by temperature control of the air or water. Where a large humidification capacity is required, an ejector which direcdy mixes air and water in a no22le may be employed. Steam may be used to power the no22le. Live low pressure steam can also be released directly into the air stream. Capillary-type humidifiers employ wetted porous media to provide extended air and water contact. Pan-type humidifiers are employed where the required capacity is small. A water filled pan is located on one side of the air duct. The water is heated electrically or by steam. The use of steam, however, necessitates additional boiler feed water treatment and may add odors to the air stream. Direct use of steam for humidification also requires careful attention to indoor air quahty. 

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