Orbifold branes in string theory and their applications to cosmology.

This dissertation contains two distinct compactification schemes of 10-dimensional string theory, as well as some of the implications of one of these schemes for string cosmology. The first half of this work begins with a brief overview of cosmology and goes through constructing and then analyzing the first model, inspired by the work of Santos and Wang. The second part consists of an attempt to construct similar models using the the popular warped conifold compactification scheme, as well as an appendix with a variant of the first model and its derivation. The work concludes with the observation that the latter attempt does not admit solutions of the same form, and that the variant model in the appendix is degenerate to previously studied KK-type models.