Also, in Rand's epistemology, it's not the sensations that are being conceptually united by the process of reason, one does not experience sensations in most normal circumstances (ie., unless you have diminished mental capacity, are in a sensory deprivation experiment, etc.) The process of integrating sensations into perception is physiological, not rational (as in Kant), one experiences a united perceptual field, rather than sensations. The process of reason proceeds, under this theory, by abstracting from the field of perception, and then integrating the units conceptually as you described.