Nauman defined in his review paper [1] that “the segregation number is… a ratio of characteristic times; a characteristic time for micromixing divided by a characteristic time for macromixing:” Nseg= τmicro/τmacroand has also selected as “a logical characteristic time for the macro-mixing is the mean residence time t.” The final result of his derivation for a spherical droplet is Nseg= 0.55r2/π2Dtfor a continuously stirred tank reactor (CSTR), where D is the diffusion coefficient and micromixing results from molecular diffusion between droplets (of packets or eddies) and the bulk of reactor fluid, and r is the radius of these droplets or eddies. It is supposed that an agitator dispersed the fluid down to the characteristic radius of r.