Lubricating Oils

Abstract

The scope of this discussion has been limited to those types of service wherein considerable quantities of lubricants are used, such as in the lubrication of industrial machine bearings, automotive internal combustion engines, and turbines. The primary object of lubrication is to provide between bearing surfaces a film of a type that will permit the conversion and the use of power without large friction losses and without serious harm to the lubricated surfaces. In the case of factory machines, shafting, motors and other housed-in equipment, where the temperature of the bearing does not fluctuate excessively, this is relatively easy since it is merely necessary to provide sufficient inactive fluid of proper viscosity to support the load. In other types of service, the conditions are far more severe. For instance, in some passenger car engines in extreme cases the lubricant must function properly over a temperature range of 350 deg. Fahr. In addition to that, it must not deteriorate too rapidly at higher temperatures nor leave an excess of residue when burned. In the following paragraphs viscosity will be discussed first, since it is the primary factor in practically all cases. It will be followed by a discussion of the limitations that must be imposed on the lubricant in special cases where the conditions of service are severe.

A Case for Molecular Recognition in Nuclear Separations: Sulfate Separation from Nuclear Wastes

“…It may be appreciated that the possibilities for crystallization of an insoluble sulfate salt largely depend on the composition of the electrolyte and the particular means for creating the insolubility condition, such as evaporation, temperature change, or addition of metal ions or other precipitating agents. Simple evaporation of Hanford LAW salt solutions has, in fact, been proposed based on expected crystallization of Na 6 (SO 4 ) 2 CO 3 (burkeite) . This fractional-crystallization approach has definite appeal in not adding more mass to the waste and potentially has the ability to bring down sulfate levels to well below the sulfate solubility limit of borosilicate glass.…”

“…This fractional-crystallization approach has definite appeal in not adding more mass to the waste and potentially has the ability to bring down sulfate levels to well below the sulfate solubility limit of borosilicate glass. Depending on the waste composition, NaNO 3 and Na 2 CO 3 ·H 2 O crystallize also, , and it has turned out that fractional crystallization by evaporation has been of greater interest recently in terms of a bulk sodium removal from medium Curie waste streams. − Such a strategy concentrates radionuclides in the liquid supernatant phase, and redissolving the solid salts yields a LAW stream. When considered only as a sulfate removal process, though, evaporation is considered to be not sufficiently selective or efficient. , Nevertheless, it may be expected that burkeite crystallization would be selective from high-sulfate waste compositions, where it would be the first phase to crystallize, especially taking advantage of its retrograde solubility (i.e., decreases with increasing temperature, in contrast to that of NaNO 3 ). , …”