The Associated Press reports that logistical issues have delayed the introduction of directed-energy weapons on the battlefied. Such issues recently led the Pentagon to delay Project Sheriff, a plan to outfit American military vehicles with a microwave-energy blaster that makes targets feel as if their skin is on fire. The directed-energy component in the project is the Active Denial System, developed by Air Force researchers and built by Raytheon Co. It produces a millimeter-wavelength burst of energy that penetrates 1/64 of an inch into a person's skin, agitating water molecules to produce heat.