“…dt = - (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21) dT T = T. + -dx, Nichols28 has adopted the attitude that the time for a pore to be swept away from a particular radius is some effective distance, Axeff' divided by its initial velocity. This quantity is essentially the .physical width of the transport -0/AT region boundary.…”