FIGURE 8.

Dependence of rolling velocity on chemical affinity. Rolling velocity, normalized to 50% of the hydrodynamic velocity (V_50%H) as a function of χ/β for several values of constant β (A) and constant χ (B). Upper and lower dashed lines indicate 0.01 V_H and 0.5 V_H, respectively. Chemical affinity does not determine a unique rolling velocity; for one value of χ/β, a range of rolling velocities exists. Conversely, rolling velocity does not require a unique chemical affinity; one value of rolling velocity can be achieved by many χ/β. At high chemical affinity, χ/β, rolling velocity is determined by β.