Washington Post: As weary visitors wait to enter the Shanghai Corporate Pavilion at Expo 2010, a sprinkler system using recycled rainwater and powered through a solar thermal system cools them off with periodic misting. Once they enter the exhibit at the world’s largest fair, tourists learn about high-speed trains and other energy-efficient inventions that have begun to proliferate in China. “Shanghai has developed so fast, its natural resources have disappeared,” reads one placard at the expo. …