Solid solutions testing method

Finally, it is not appropriate to derive thermodynamic properties of solid solutions from experimental distribution coefficients unless it can be shown independently that equilibrium has been established. One possible exception applies to trace substitution where the assumptions of stoichiometric saturation and unit activity for the predominant component allow close approximation of equilibrium behavior for the trace components (9). The method of Thorstenson and Plummer (10) based on the compositional dependence of the equilibrium constant, as used in this study, is well suited to testing equilibrium for all solid solution compositions. However, because equilibrium has not been found, the thermodynamic properties of the KCl-KBr solid solutions remain provisional until the observed compositional dependence of the equilibrium constant can be verified. One means of verification is the demonstration that recrystallization in the KCl-KBr-H20 system occurs at stoichiometric saturation. 

That portion of solids and aqueous solution in an emulsion that separates out on standing or is separated by centrifuging in a standardized test method. Basic sediment may contain emulsified oil as well. Also referred to as BS W, BSW , Bottom Settlings and Water, and Bottom Solids and Water. 

Water treatment A standard test method in which either the coagulant dosage is varied or the solution pH is varied for a given coagulant dosage, to optimize the coagulation of solids. Frequently termed jar test . 

The simplest strategy for determining the structure of a compound prepared on a single bead is encoding. This indirect method of structure determination can be used both with testing methods that involve bead bound ligands as well as with solution methods that use material removed from the solid support. 

The types of sedimentation encountered in process technology will be greatly affected not only by the obvious factors—particle size, liquid viscosity, solid and solution densities—but also by the characteristics of the particles within the slurry. These properties, as well as the process requirements, will help determine both the type of equipment which will achieve the desired ends most effectively and the testing methods to be used to select the equipment. 

The polynuclear aromatic content of waxes can be estimated by the ultraviolet absorbance (ASTM D-2008) of an extract of the sample. In this test method, the ultraviolet absorbance is determined by measuring the absorption spectrum of the undiluted liquid in a cell of known path length under specified conditions. The ultraviolet absorptivity is determined by measuring the absorbance, at specified wavelengths, of a solution of the liquid or solid at known concentration in a cell of known path length. 

Hydrophobic Index An empirical measure of the relative wetting preference of very small solid particles. In one test method, solid particles to be tested are placed in samples of water containing increasing concentrations of alcohol. The percentage alcohol solution at which the particles just begin to become hydrophilic and sink is taken as the hydrophobic index. See also Chapter 12. 

When any likely impurities in the system readily form solid solutions in the crystals, they may be very difficult to remove by conventional methods. Effects of such foreign molecules in the crystal lattice can profoundly modify barriers to molecular rotation, and can thereby enhance premelting. In favourable cases, this can be tested by the direct addition of the appropriate impurity, whose structure must be so close to that of the primary molecules that the foreign species can easily be accommodated in the crystals. Some experimental examples have been investigated by Ubbelohde, Oldham and Ubbelohde, and Thompson and Ubbelohde (cf. Reference 27). 

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