The general methodology of TAP data analysis, developed in a series of papers by Grigoriy (Gregory) Yablonsky 
is based on comparing an inert gas response which is controlled only by Knudsen diffusion 
with a reactive gas response which is controlled by diffusion as well as adsorption and chemical reactions on the catalyst sample.
TAP pulse-response experiments can be effectively modeled by a one-dimensional (1D) diffusion equation with uniquely simple combination of boundary conditions.