  Large-scale radial transport of solids appears to be a fundamental
consequence of protoplanetary disk evolution based on the presence of high
temperature minerals in comets and the outer regions of protoplanetary disks
around other stars. Further, inward transport of solids from the outer regions
of the solar nebula has been postulated to be the manner in which short-lived
radionuclides were introduced to the terrestrial planet region and the cause of
the variations in oxygen isotope ratios seen in primitive materials. Here, both
outward and inward transport of solids are investigated in the context of a
two-dimensional, viscously evolving protoplanetary disk. The dynamics of solids
are investigated to determine how they depend on particle size and the
particular stage of protoplanetary disk evolution, corresponding to different
rates of mass transport. It is found that the outward flows that arise around
the disk midplane of a protoplanetary disk aid in the outward transport of
solids up to the size of CAIs and can increase the crystallinity fraction of
silicate dust at 10 AU around a solar mass star to as much as $\sim$40% in the
case of rapidly evolving disks, decreasing as the accretion rate onto the star
slows. High velocity, inward flows along the disk surface aid in the rapid
transport of solids from the outer disk to the inner disk, particularly for
small dust. Despite the diffusion that occurs throughout the disk, the
large-scale, meridonal flows associated with mass transport prevent complete
homogenization of the disk, allowing compositional gradients to develop that
vary in intensity for a timescale of one million years.
