杏吧原创

Police in the US use firework-like stun grenades, known as 鈥渇lash-bangs鈥�, to disorient hostage-takers before rushing in to capture them. The canisters鈥攚hich are loaded with metal powder and solid oxidiser鈥攁re not high explosives, but they can injure someone if they go off next to the head. Now Sandia National Laboratories in New Mexico has developed a safer alternative. Pulling a grenade-like pin on the plastic canister ignites a couple of grams of a black powder propellant, producing hot gas that sprays fine aluminium dust through 16 holes in the canister to form a cloud 1.5 metres-across. The hot gas and a few hot particles ignite the dispersed aluminium dust, which produces a flash and a bang that are powerful enough to stun. The new device is safer than conventional ones because the energy is released over a larger volume, says Sandia. Police departments have already expressed interest in the idea.