U.S. Air Force Staff Sgt. Dustin Volpi, 354th Logistics Readiness Squadron fuels distribution supervisor, tests liquid oxygen for purity March 20, 2012, Eielson Air Force Base, Alaska. Quality liquid oxygen is used to provide oxygen to pilots and aircrews at altitudes above 10,000 feet.
U.S. Air Force photo/Staff Sgt. Jim Araos
<a rel="nofollow" class="external free" href="http://www.eielson.af.mil/News/ArticleDisplay/tabid/1819/Article/382562/cryogenics-keeps-it-cool-in-the-ice.aspx">http://www.eielson.af.mil/News/ArticleDisplay/tabid/1819/Article/382562/cryogenics-keeps-it-cool-in-the-ice.aspx</a>