Surface consolidation

During consolidation of plaster and rendering, problems arising may be the same as that of surface consolidation. However, to see these changes beneath the paint layer in the early stages may be much more difficult. Modem... 

Figure 9 SEM of microorganisms growing beneath Klucel surface consolidation, Salzhemmendorf Germany...

More investigations are necessary to formulate flexible polyester resins that produce a nontacky surface after air irradiation. Flexibility is important in order to reduce the radial and tangential shrinkages. No air inhibition is important in obtaining a good surface consolidation. 

Surface consolidation, where little strain is placed on the object, other than handling, may provide ample stabilization. These conditions might best be managed by the use of reversible surface resins such as the acryloids or not dewaxed shellac resins in reduced concentrations of ethanol. 

Sludge in drainage surface Consolidation of sludge in surface ... 

Both reinforcements provide a random orientation, the mat resulting in more fibres parallel to the mould surface. Consolidation is easier with the mat, but care is required with complex surfaces to ensure that rovings as well as resin are present. 

In a similar manner, calcium chloride is effective in surface consolidation, base stabilization, and compaction during road construction. For the latter use, it is added as either liquid or flake to the aggregate as it is being laid down, or to plant... 

Sand production from loosely consolidated formations may lead to erosion of tubulars and valves and sand-fill in of both the sump of the A/ell and surface separators. In addition, sand may bridge off in the tubing, severely restricting flow. The presence of sand production may be monitored by in-line detectors. If the quantities of sand produced become unacceptable then downhole sand exclusion should be considered (Section 9.7). 

What is observed is that there are significant changes in specific surface, but that they are relatively modest and cannot account for large changes in reaction rates in shocked powders. The observed behavior can be characterized into typical behaviors as summarized in Fig. 7.1. If comminution is the dominant behavior, the specific surface area will be observed to increase. Such a behavior is called Type a. If consolidation is the dominant behavior, specific surface area will be observed to decrease. Such a behavior is called Type b. In the most typical case, the specific surface increases at low pres-... 

Fig. 7.1. Observed specific surfaces for shock-modified powders show four typical behaviors indicative of (a) comminution, (b) consolidation bonding, (c) comminution followed by bonding, and (d) comminution after phase transformation [85L01].

Spray molding is the modification of the hand-lay process where the resin and glass fiber are deposited simultaneously on the molding tool. The fibers are mixed with the resin at the spray head before being deposited on the mold surface. Subsequent consolidation of the laminate is achieved by rolling in a similar manner to the hand-lay process. This method is suitable for large components. Here the capital cost is higher and the process is very operator sensitive. 

The uniformity of film thickness is dependent upon temperature and pressure. The nucleation rate rises with pressure, such that at pressures above atmospheric the high rate of nucleation can lead to comparatively uniform oxide films, while increase in temperature reduces the density of oxide nuclei, and results in non-uniformity. Subsequently, lateral growth of nuclei over the surface is faster than the rate of thickening until uniform coverage is attained, when the consolidated film grows as a continuous layer ... 

Sprayed coatings have structures in which fine pores thread tortuous paths through the deposit, and it is necessary to apply a coating thickness of about 350 ftm if all these paths are to be closed. Scratch-brushing of the deposit, however, makes it possible to consolidate the surface and to achieve adequate continuity in thinner deposits, e.g. 200 m. 

The attack of most glasses in water and acid is diffusion controlled and the thickness of the porous layer formed on the glass surface consequently depends on the square root of the time. There is ample evidence that the diffusion of alkali ions and basic oxides is thermally activated, suggesting that diffusion occurs either through small pores or through a compact body. The reacted zone is porous and can be further modified by attack and dissolution, if alkali is still present, or by further polymerisation. Consolidation of the structure generally requires thermal treatment. 

Spray-up Popular system with reinforced plastic production. An air spray gun includes a roller cutter that chops usually glass fiber rovings to a controlled short length before being blown in a random pattern (manually or automatically) onto a surface of the mold simultaneously the gun sprays catalyzed TS polyester plastic. The chopped fibers are plastic coated as they exit the gun s nozzle. The resulting, rather fluffy, RP mass is consolidated with serrated rollers to squeeze out air and reduce or eliminate voids. A closed mold... 

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