Sketch of the disk and processes used in our calculations. Three shades of gray show the regions clear of dust, with optically thin dust, and with optically thick dust. The beginning of the optically thick disk at R_in is defined as the disk rim. White dots mark the zone dominated by big grains, L_∗ is the stellar luminosity, L_acc is the accretion luminosity, VH the viscous heating, TD the turbulent diffusion, G the gravity, C the centrifugal force, DS the dust settling due to the gas drag force, PG the gas pressure gradient, RP the radiation pressure, and VP is the gas velocity profile.