Cryogenic
Staff Sgt. William Veal, 455th Expeditionary Logistics Readiness Squadron cryogenic technician, samples liquid nitrogen at Bagram Airfield, Afghanistan, May 20, 2011. Cryogenics supplies liquid oxygen and nitrogen which service the F-16 Strike Eagles. Sergeant Veal is deployed from Yokota Air Force Base, Japan and is a native of Warner Robins, Ga. (U.S. Air Force photo by Senior Airman Sheila deVera)