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. the deployment options of Blackboard Learn to include public cloud, and improvements to Blackboard's mobile app. , Blackboard serves approximately 17,000 schools and organizations. It holds the highest share of the education market with 75 percent of colleges and universities and more than half of K-12 districts in the US using its products and services. , Blackboard had acquired MyEdu, Perceptis, and CardSmith, and Requestec under Bhatt's leadership. The acquisitions reflected Bhatt's new acquisition strategy of making investments that serve students and will lead to innovations in Blackboard's core teaching and learning products. Blackboard has used the acquisition of other