a$.$ Is there any evidence that stirring rate impacts grain size?

From the analysis I can tell that there is no evidence that supports that the stirring rate affects the grain size of the products.

b$.$ What should the process engineers recommend concerning the choice of stirring rate and fumace for this pariculargrain refiner if small grain size is desirable?

Given the wide range, I think they would argue that there wouldn't be any difference because of halteringthe stirringpace.