Mobility ratio experimental results

Relaxation times Tt and T2 have been determined as a function of temperature and surface coverage in various zeolites, particularly of the faujasite type. The early experiments have been troubled by the very strong dependence of relaxation rates on the concentration of paramagnetic impurities. In order for the relaxation values to be meaningful, such impurities expressed as Fe content must be below ca. 6 ppm. Figure 38 shows the variation of Tt and T2 for water adsorbed in a particularly pure sample of zeolite Na-X (248). The authors (248) account for the experimental results using a model of the intracrystalline fluid, which is about 30 times as viscous as bulk water at room temperature. It shows a broad distribution of molecular mobilities (the ratio T,/T2 at the minimum in Tt is much larger... 

If either the mobility ratio or the density ratio is unfavorable, instabilities can form at the injection boundary as the result of infinitesimal perturbations. But if the concentration is changed sufficiently slowly with time at the entrance to the system, the displacement can be stabilized, even if both the mobility ratio and the density ratio are unfavorable. At least for neutral density ratios, this was anticipated by the experimental observations of Slobod and Lestz (19) and of Kyle and Perrine (18). 

The catalyst was prepared by agglomerating the HZSM-5 zeolite (25 wt%) with bentonite (Exaloid, 30 wt%), using fused alumina (Martinswerk) as inert charge (45 wt%). The HZSM-5 zeolite was synthesized with a Si/Al ratio, Si/ A1= 24, following Mobil patents [10,11]. The properties of the HZSM-5 zeolite and of the catalyst are set out in Table 1. Prior to use, the catalyst was calcined at 843 K for 2 h (for the experimental results to be reproducible under reaction-regeneration cycles) [12]. 

Hence, the ratio of APg to AP is 0.2. The conclusion that it is about 5 times more difficult to mobilize entrapped fluid than to prevent entrapment is in fair agreement with the experimental results presented in Figure 11. With respect to interpretation of experimental results, it would seem reasonable to expect that the correct relationship for mobilization of residuals in sphere packs will lie somewhere between the sphere pack results, which, because of solution effects represent a lower limit, and the curve obtained for rocks of narrow pore size distribution. 

Bank size may be determined experimentally. Results of a mixing-zone study done in a 16-ft Berea sandstone core illustrate one approach. In this study, glycerine, biopolymer, and polyacrylamide solutions of various mobilities were displaced through the core by drive water. The length of the mixing zone was determined from effluent concentrations to be the volume between the 5 % and 95 % concentrations. Fig. 5.96 summarizes the results. The mixing-zone volume is a function of mobility ratio, as would be expected. For example, the mobility buffer must be 0.5 PV to prevent reduction... 

Relations (25) to (31) which were derived for the limiting situation Cp< Cs are limiting laws with respect to the salt-to-polymer concentration ratio. In practice they apply as long as experimental results are extrapolated to infinite polyelectrolyte dilution and the ionic strength is kept at finite values, w and 1/2 1 electrophoretic mobilities,... 

Figure 2, A, represents the experimental heat capacity data in the temperature range between 20° and 360° K. for H2 in Pd4H2—i.e., Pd4H2 minus the heat capacity of the palladium atoms in palladium black (7) and block palladium (5). In Figure 2, B, C, and D represent the similarly calculated experimental contributions for H2 in the other samples studied which had H/Pd ratios of 0.75, 0.25, and 0.125. Above 120° K. the results for palladium black are noticeably different from all of the others. This is apparently due to the fact that in palladium black, owing to the smallness of the particles, the lattice is somewhat more mobile. In Figure 3 all the experimental contributions of two hydrogen atoms to the heat capacity for alloys of compositions H/Pd = 0.75, 0.50, 0.25, and 0.125 are plotted between 35° and 85° K. (5). All the points lie on a single curve, within experimental error. Such a situation is difficult to conceive unless the hydrogens are similarly located with respect to each other in all samples.

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