Calcium sulfate an unusual property: when mixed with water at normal (ambient) temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice: This reaction is exothermic and is responsible for the ease with which gypsum can be cast into various shapes including sheets (for drywall), sticks (for blackboard chalk), and molds (to immobilize broken bones, or for metal casting). Mixed with polymers, it has been used as a bone repair cement. Small amounts of calcined gypsum are added to earth to create strong structures directly from cast earth, an
Blackboard Inc. to the non-profit IMS Global Learning Consortium developing a prototype for online learning and thinking through online learning standardization. Chasen and Pittinsky started Blackboard after leaving KPMG Consulting where they both had worked as part of the company's higher education practice. In 1998, after Cane met Chasen at a conference on adaptive learning, Gilfus and Cane decided to merge CourseInfo LLC. with Chasen and Pittinky's Blackboard LLC. company in order to raise money and scale the business. The combined company became a corporation known as Blackboard Inc. They renamed the CourseInfo platform built by the Cornell team to Blackboard's CourseInfo;