Mixing earliness/lateness

Arrington C A, Morse M D and Doverstal M 1995 Spectroscopy of mixed early-late transition metal diatomics ScNi, YPd, and ZrCo J. Chem. Rhys. 102 1895... 

A variety of acetylide complexes have been reported with mixed early-late transition metal or mid-late transition metal complexes. The synthetic procedures either... 

PF can be used to illustrate extremes described by early mixing and late (or no) mixing. In BMF, mixing of fluid elements of all ages takes place early -at the point of entry. In PF, mixing takes place late -in fact, not at all (in the axial direction). We may then use a combination of two vessels in series, one with BMF and one with... 

Since CSTRs and PFRs represent the extremes of mixing, the best order wUl depend on whether it is better to mix when the reactant concentrations are high or when they are low. Stated differently, is it better to mix early in the reaction (when the conversion is low) or to mix late in the reaction (when the conversion is high) The answer depends on the rate equation. 

These generalizations apply to a situation where the amount ofmixing is fixed, and the only question is whether to mix early or late in the reaction. The generalizations do not mean that mixing is beneficial. Obviously, based only on the total volume required, mixing is undesirable in all three of these cases. We would use a PFR in all three situations, if that were allowable. 

Reclaim Rubber. The process of reclaiming mbber by chemical digestion has been in use since the late 1800s. Early processes involved the treatment of the mbber cord mix with acid. Acids attack cotton, rayon, and nylon. The acid treatment was used to remove the reinforcing components. 

This occurs when the nocturnal inversion is dissipated by heat from the morning sun. The lapse layer usually starts at the ground and works its way upward (less rapidly in winter than in summer). Fumigation may also occur in sea-breeze circulations during late morning or early afternoon. The shaded zone of strong concentration is that portion of the plume which has not yet been mixed downward. 

How early or late mixing of material oeeurs in the system. 

As cooling occurs in the late fall and early winter, the thermal stratification breaks down, permitting mixing of the deep and surface layers. This allows the surface layers to be replenished with P. During the winter months, biological productivity in a temperate lake is limited by the availability of light rather than nutrients. 

The forms of actual tracer response curves may be used to formulate models of the actual mixing processes in the reactor. One has, however, to be careful since the tracer response curve does not give a unique solution. It does, for example, not allow one to distinguish between early and late mixing, which may be important when used in the estimation of conversion in a particular reactor-reaction system. 

---