Ratio and Dilutability

If a non-solvent is added dropwise to a cellulose nitrate solution, the cellulose nitrate eventually separates as a precipitate or gel. The volumetric ratio of non-solvent to solvent that is still tolerated in the solution is termed the dilution ratio. The dilution ratio is an empirical, dimensionless quantity that provides information on the solvency of a solvent or solvent mixture. In order to determine the dilution ratio toluene or butanol is used as diluent (non-solvent). 

Mixtures of two solvents frequently have a higher dilution ratio than the pure components ether-alcohol and toluene ethanol mixtures are better solvents for cellulose nitrate than any of the pure solvents ethyl acetate and butyl acetate are 

As expected, the dilution ratio falls with rising cellulose nitrate concentration in the solution (Table 8). 

The dilution ratio reveals some similarities between the solvency of different solvents. However, most measurements are restricted to cellulose nitrate, and extrapolation of the results to other binders seldom provides correct results. Furthermore the dilution ratios, unlike solubility parameters, are unable to explain several phenomena (e.g., the enhancement of the solvency of a solvent produced on adding a non-solvent). 

The apparent or theoretical dilutability denotes the dilution ratio that just results in a saturated solution. The true or practical dilutability predicts that this solution to which diluent has been added can still be applied satisfactorily, for example in the paint sector clear varnish films can form from these solutions after drying. 

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The ground composite pigment was then incorporated into an epoxy primer at various pigment volume concentrations (PVQ. The primer was prepared by mixing epon 828 and epikure 3175inal 1.2 ratio and diluting it with methyl isobutyl ketone. The composite pigment was then added and more methyl isobutyl ketone was added... 

Because tetrahydrofurfuryl alcohol is virtuaHy colorless, it is used in lacquer formulations for aH colors as weU as water-white clear products. More speciftcaHy, tetrahydrofurfuryl alcohol is a wetting dispersant for most pigments. It has a high boiling point, high toluene dilution ratio, and good miscibility with oils, eg, linseed and soya, and is an exceUent solvent for a wide range of resins. 

As a general rule, however, textile fibers do not wet out readily, are difficult to disperse, and tend to tangle with one another. Consequendy, large amounts of water are necessary to keep the fibers suspended. Further, if the slurry is not handled propedy, the fibers tangle and cause poor sheet formation. Two approaches to resolving these difficulties are increasing slurry—dilution ratio and controlling fiber orientation. 

Table 4. Blush Resistance and Dilution Ratio of Common Industrial Solvents ...

Extraction. Traditionally tea leaf is extracted with hot water either in columns or ketdes (88,89), although continuous Hquid soHd-type extractors have also been employed. To maintain a relatively low water-to-leaf ratio and achieve full extraction (35—45%), a countercurrent system is commonly used. The volatile aroma components are vacuum-stripped from the extract (90) or steam-distilled from the leaf before extraction (91). The diluted aroma (volatile constituents) is typically concentrated by distillation and retained for davoring products. Technology has been developed to employ enzymatic treatments prior to extraction to increase the yield of soHds (92) and induce cold water solubiUty (93,94). 

This anomalous pH behavior results from the presence of polyborates, which dissociate into B(OH)2 and B(OH) as the solutions are diluted. Below pH of about 9 the solution pH increases on dilution the inverse is tme above pH 9. This is probably because of the combined effects of a shift in the equihbrium concentration of polymeric and monomeric species and their relative acidities. At a Na20 B202 mol ratio equal to 0.41 at pH 8.91, or K20 B202 mol ratio equal to 0.405 at pH 9 the pH is independent of concentration. This ratio and the pH associated with it have been termed the isohydric point of borate solutions (62). 

Feed Composition. Feed composition has a substantial effect on the economics of a distillation. Distillations tend to become uneconomical as the feed becomes dilute. There are two types of dilute feed cases, one in which the valuable recovered component is a low boiler and the second when it is a high boiler. When the recovered component is the low boiler, the absolute distillate rate is low but the reflux ratio and the number of plates is high. An example is the recovery of methanol from a dilute solution in water. When the valuable recovered component is a high boiler, the distillate rate, the reflux relative to the high boiler, and the number of plates all are high. An example for this case is the recovery of acetic acid from a dilute solution in water. For the general case of dilute feeds, alternative recovery methods are usually more economical than distillation. 

Although the RSF contains matrix-dependent quantities, their variations are damped to some extent by virtue of taking ratios, and in practice the RSF is assumed constant for low concentrations of A (e. g. <1 atom%). It can be evaluated from measurements on a well-characterized set of standards containing A in known dilute concentrations. The accuracy of the method, however, is not as high as in laser-SNMS and XPS. 

Grignard reagent and dilution factors determine the ratio of the... 

Figure 4.36. Cross validation between two HPLCs A stock solution containing two compounds in a fixed ratio was diluted to three different concentrations (1 10 20) and injected using both the 10 and the 20 /xl loop on both instruments. The steps observed at Amount = 100 (gray ellipses) can be explained with effective loop volumes of 9.3 and 20 pi (model 1) and 14.3 and 20 pi (model 2) instead of nominally 10 and 20 pi. This is irrelevant as both a sample and the calibration solution will be run using the same equipment configuration. The curved portion of the model 2 calibration function was fitted using Y = A /x this demonstrates the nonlinearity of the response at these high concentrations. The angle between the full and the dotted line indicates the bias that would obtain if a one-point calibration scheme were used.

Typical re-entrant piston-bowl design for a small, high-speed direct-injection Cl engine. (From Kook, S., Bae, C., Miles, P.C., Choi, D., Bergin, M., and Reitz, R.D., The Effect of Swirl Ratio and Fuel Injection Parameters on CO emission and Fuel Conversion Efficiency for High-Dilution, Low-Temperature Combustion in an Automotive Diesel Engine, SAE, 2006-01-019 2006. With permission.)... 

Table 1 lists MORE studies to date and Figures 2 and 3 present data from different areas of ridge. The first study of U-series disequilibria in MORE was the pioneering work of Condomines et al. (1981) (Fig. 2A). These workers analyzed samples having a relatively wide range in composition (Mg 72 to 57) from the FAMOUS region of the Mid-Atlantic Ridge (MAR 37°N) by combined alpha spectrometry (for U and Th isotopic ratios) and mass spectrometry (isotope dilution measurements for U and Th... 

The fresh fruit was ground in a meat chopper, and the juice was pressed out and diluted with tap water at ratios of 1 to 7.5, 1 to 15, and 1 to 30. The processed baby food was also diluted with tap water at the same ratios as the ground fresh fruit. 

Table 2 shows every measured value necessary to calculate the average molweight of silicates in various solutions. It also permits to follow the step by step calculation as detailed in our previous papers [8,9], It was found that, in contrast to the common belief, every dilute alkaline silicate dissociates only partly at the concentrations studied. The AMW, expressed as number of [Si04] tetrahedra per silicate ion in the last column of this table, clearly depends on the type of A+ ions, the A/Si ratios, and the concentration. In general AMW decreases with increasing dilution as one can expect and it is lower in the high A/Si ratio silicates (Kasil 1624 and Star) than in the other silicates at comparable concentrations. 

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