Solid forces

Table 5.8b Isotope independent gas, liquid and solid force fields for water. Units are mdyn/A for stretches and mdyn — A/rad2 for bends (Van Hook, W. A. J. Phys.Chem 72, 1234 (1968)) ...

Species Type of Solid Forces within Solid Melting Point... 

Since membrane-cell evaporators do not produce solids, forced-circulation evaporators are used less frequently. Rising-film and falling-film types appear in a number of plants. The rising-film evaporator depends on natural circulation of caustic from the bottom to the top of the tubes. Falling-film evaporators, as shown in Section 9.3.S.2, depend on pumps to lift caustic to the distribution system at the top. These units generally have better heat-transfer coefficients and less tendency to foul. Recirculated units in particular allow good control of flow to maintain a proper film on the tubes. This also permits the designer to provide more turndown capability. Liquid velocities are lower... 

The simplest and most common method of determining the surface tension of a liquid is the capillary tube rise method. If a glass capillary tube is immersed in a liquid such as water, the liquid in the capillary tube will rise above the outside level of the liquid. This is due to the greater liquid-solid force than the liquid-liquid intermolecular forces, and the liquid tends to wet as much of the solid... 

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