Practical Saturation

The ultimate condition will be at the initial water temperature B. Practical saturation efficiencies (the ratio AC/AB) will be about 50-80% for air washers having a single bank of sprays and 80-95% for double spray banks (see Figure 24.8). 

A sample of water-dried powder was exposed to an atmosphere practically saturated with water vapor. Portions were removed each day one part was fired in the gun, and another part was analyzed for total volatile matter (TV) and for volatile matter driven off by an hour s heating at 100° (external moisture, EM). 

There appears really to be no method by which true external moisture may be determined, that is, no method by which only the surface moisture is removed in such fashion that the residual solvent in the powder is found to be the same both before and after the powder has been allowed to take up moisture. Samples of powder were taken and residual solvent was determined by the several methods indicated in the next table. The samples were exposed 2 weeks to an atmosphere practically saturated with water vapor, and residual solvent was again determined as before. The surprising result was secured in every case, as indicated, that the amount of residual solvent was less after the powder had been exposed to the moist atmosphere than it was before it had been exposed. Yet the powder had taken up large quantities of moisture during the exposure. It is clear that the exposure to the moist atmosphere had made the volatile matter of the interior of the grains more accessible to desiccating influ-... 

This can be prepared simply by stirring a cold, practically saturated aqueous solution of mercury (II) chloride into a cold, practically saturated aqueous solution of thiourea until the white precipitate (of the di-derivative) almost entirely redissolves. Large, colorless crystals separate out when the solution is filtered and allowed to evaporate at ordinary temperature, say, in a vacuum desiccator. The crystals may be dissolved in hot water, whereupon little decomposition takes place, and square microscopic platelets crystallize out of the filtered solution on cooling. The dried crystals sinter at about 174° and begin to decompose at about 179°. The yield is only moderately good. Anal. Calcd. for HgCl2-3CSN2H4 N, 16.80. Found N, 16.76, 16.89. 

Van t Hoff5 gives two rules, which, although applying in theory only to the solution of a substance in one already practically saturated, usually hold for ordinary solution. The rules are as follow ... 

Ammonia TS, Stronger (15.2 A in NH3) (Ammonium Hydroxide Stronger Ammonia Water) Use ACS reagent-grade Ammonium Hydroxide, which is a practically saturated solution of ammonia in water, containing between 28% and 30% of NH3. 

These curves are practically saturation curves, their intercept with the voltage axis lying very close to the origin and being nearly independent of the frequency of alternation. Their ordinates are, however, but half of thoSe for the corresponding saturation curves. This is to be expected since the time during which the electrometer deflection was measured... 

Few reactions of CIO2 with hydrocarbons have been reported except under conditions very far removed from water treatment practice. Saturated alkanes and alkyl side chains appear almost inert in its presence except where unusually stable radicals may result (benzylic hydrocarbons, e. g.). In these cases, typical products of autooxidation (see Chapter 4) have been isolated, probably by attack of O2 on intermediate free radicals formed by electron transfer (Ozawa and Kwan, 1984 Rav-Acha and Choshen, 1987 Merenyi et al., 1988) or (less likely) hydrogen atom abstraction (Chen et al., 1982). A few polycyclic hydrocarbons have been shown to be partially converted to chlorinated derivatives and quinones by CIO2 (Thielemann, 1972a Taymaz et al., 1979). 

In order to perform a simple competition study it is necessary to first determine the minimal concentration of competitor needed to saturate its own transport. To calculate intracellular concentrations of microinjected macromolecules we have taken the accessible volume of the nucleus to be 40 nl and the cytosol to be 500 nl (Gurdon and Wickens, 1983). In practice, saturation concentrations are operationally defined as the minimal unlabeled substrate concentration necessary to reduce significantly the rate of labeled tracer substrate transport. If too high a concentration of unlabeled competitor is used, then nonspecific inhibitory effects on tracer substrate transport can be expected. 

The results presented in Figures 10 and 11 show the NO2 absorbed by water as a function of time for various SSR and gas phase NO2 concentrations. The results are normalized to the saturation concentration at the temperature of the droplet when sampled. For the tests at both 100 and 300 ppm NO2 in the gas phase, the droplets were practically saturated with NO2 within 5 seconds of exposure. 

After studying hundreds of concentrated cooling waters, Puckorius and Brooke [36] proposed a new index, the practical saturation index (PSI),... 

In the immersion zone (IZ) as well, the water is practically saturated with oxygen. In addition to fouling, solute contaminants, suspended solids and water currents are additional factors to be reckoned with here. 

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