(PhysOrg.com) -- Many scientists currently think at least 5 percent of humanity's carbon footprint comes from the concrete industry, both from energy use and the carbon dioxide (CO2) byproduct from the production of cement, ...
Environment
May 18, 2009
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Most of the time, we use the stairs in buildings—especially in high-rise structures—only as a back-up for faster elevators and escalators, but during a fire or other emergency, stairs become our primary passage to survival. ...
Other
Mar 25, 2009
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