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Submission + - The vortex gun - coming soon to a protest near you?->

An anonymous reader writes: From the article: Vortex technology has been used in everything from rocket-powered fire extinguishers to Nerf guns, but neither of those things are capable of giving the beat-down to hapless protesters. By giving spinning vortices an electric charge, though, pepper spray can be sent over 150 feet at between 60 and 90 mph.

A vortex gun uses a pressure wave and a carefully designed barrel to fire donut-shaped rings of air that can hold themselves together over long distances. The military (starting with the German military during World War II) has been running experiments with using vortex canons to knock things over, but it's not a particularly efficient or effective way to go. What the gas rings can be used for is transporting other gasses (like pepper spray or tear gas or pesticide) long distances with a decent amount of accuracy, holding their cargo inside the calm center spinning vortex

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Comment Re:Sort of Hawking Radiation (Score 1) 165

heisenberg: uncertainty in energy times uncertainty in time has a lower bound. what is the energy of the phonons? given the small time that heisenberg allows the virtual phonon pairs to exist, how far can the phonons travel? without actually working out the numbers, my seat of the pants guess is that the number of virtual phonon pairs for which one member crosses the acoustic event horizon will be vanishingly small.

Promising costs nothing, it's the delivering that kills you.