Senior Airman Jesse Silva adjusts the knobs on a Hammonds Additive Injector July 16, 2013, in Southwest Asia. Silva does this to regulate how much additive is injected into the squadron's first delivery of commercial Jet A1. Silva is a 386th Expeditionary Logistics Readiness Squadron bulk storage attendant. (U.S. Air Force photo/Master Sgt. Christopher A. Campbell)