Pressured-Induced Reversal between Thermal Contraction and Expansion in Ferroelectric PbTiO_3 - 18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT) PostDeadline