The solution of these equations in principle defines a three-dimensional and transient field of the relevant variables such as temperature or species. However, the application of these conservation principles to a large number of particles usually restricts the resolution to at most one representative dimension and time due to CPU time consumption. Experimental evidence at least in reaction engineering supports the assumption of one-dimensionality as pointed out by Man and Byeong, while the importance of a transient behaviour is stressed by Lee et al.