Corrected from single-component measurements

The corrected diffusivities (Dqa, Dob) can be derived from single component measurements but the mutual diffusivity (Dab) is not amenable to direct measurement. Krishna has suggested using the Vignes correlation [32] as an estimation method ... 

SIM experiments for binary N2-O2 mixtures on Li,RE-LSX zeolite were performed in conjunction with single-component investigations. Mixture measurements are exemplified by isosteres for a sorption-phase composition of 80 % N2 and 20 % O2 as shown in Figure 24, over the entire concentration ranges for zeoUtic intracrystalline void volume up to filling secondary pore volumes of the beads, as also observed from isosteres. In those representations, each Une of symbols is one isostere measured at the respective sorption-phase concentration. As the latter concentration approaches saturation, the orresponding isostere approaches the sublimation curve of either the single component or the binary mixture. The coincidence between isostere and sublimation curve beyond saturation capacity proves that isosteric measurements were correct and thermodynamically consistent. 

First, the hypothesis that the residuals Tmj represent a sample of the universe of the experimental errors can be tested via different methods in order to single out the presence of systematic errors deriving from the inadequacy of the mathematical model. In particular, it is possible to test whether, for any measured component m, the mean of the residuals Tmj (for j = 1,..., IVd) is significantly different from zero (which is the expected value) and whether, for any measured component, the corrected residual variance s m is significantly different from the universe variance er2, which can be computed by resorting to repeated measurements, as shown by (3.8). 

Imperfections in pulses also may be corrected by using composite pulses instead of single pulses. The 180° pulse that inverts longitudinal magnetization for the measurement of T or other purposes may be replaced by the series 90, 180°, 90°, which results in the same net 180° pulse angle, but reduces the error from as much as 20% to as little as 1%. As Figure 5-27 shows, the 180° pulse compensates for whatever imperfection existed in the 90° pulse. (Normally, 180° is taken as double the optimized 90° pulse, so errors in one are present in the other). The three components of the WALTZ-16 method (90°, 180°, 270°) also constitute a composite pulse for 180°. 

---