Cooling chemical composition

The presence of tubercles is usually obvious. Friable brown and orange nodular encrustations on mild steel and cast iron cooling water components are almost always tubercles (Figs. 3.12 through 3.14). The presence of a crust, shell, core, cavity, and corroded floor are definitive (Fig. 3.3). Careful analysis can provide considerable information concerning growth, chemical composition, and associated metal loss. 

In Bridgman growth [155], a boat or vessel filled with the melt is slowly cooled from one side, so that the crystal forms from that side. In Czochralski growth [156,157] a cylindrical crystal sits on the surface of the melt and is slowly pulled upward. In both cases the hydrodynamical flow of the melt is an important factor in the chemical composition and fine structure of the resulting crystal. 

For example, consider the chemical composition of a very old crystal of pitchblende, U308. We may presume that this crystal was formed at a time when chemical conditions for its formation were favorable. For example, it may have precipitated from molten rock during cooling. The resulting crystals tend to exclude impurities. Yet, careful analysis shows that every deposit of pitchblende contains a small amount of lead. This lead has accumulated in the crystal, beginning at the moment the pure crystal was formed, due to the radioactive decay of the uranium. 

The caramelization process can be conducted in open or closed vessels. The mixture obtained is cooled and filtered, and then the pH and specific gravity are adjusted by the addition of acids, alkalis, or water. The chemical composition and properties of caramel colors depend on reactants used and technical conditions such as time, temperature, moisture content, and pressure. During the caramelization... 

Sample for Chemical Composition Analysis is taken by catching a portion of the molten expl compn, from the approx center of the batch, and pouring into shallow A1 dish 4 inches in diam in order to obtn on cooling a wafer approx % inch thick... 

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