Mesoporous solids play an important role as gas adsorbents, cat-

alysts, or porous barriers in a wide range of applications relating

to chemical, biomedical, or environmental engineering; the intelli-

gent design of which presupposes fundamental understanding of

the physical principles and mechanisms underlying the gas adsorp-

tion and permeability properties of the said solids in relation to

their structure. This in turn requires astute idealized modeling,

which aims at identifying and correlating the essential features of both physics and structure (in contradistinction to simulation, which

seeks to reproduce reality in all its complexity).