Abstract: Electric arc monitoring is effected by exploiting the discovery that electric arcs are fractal phenomena in that all essential information that signifies “arc” is contained in each fractal subset. These fractal subsets are logarithmically distributed over the arc spectrum. Monitoring of arcs is most advantageously effected on a fractal subset (16) of low logarithmic order where the amplitude is higher pursuant to the 1/f characteristic of electric arcs, where cross-induction among neighboring circuit is lower, and where travel between the arc (12) and the arc signature pickup (23) is longer than at the high frequencies customary for electric arc detection. Fractal subset transformation (17) reduces the danger of false alarms. Arc signature portions may be processed in out of phase paths (242, 342) or treated as modulated carriers (42) for monitoring.

Abstract: Methods and apparatus for destroying snails avoid a cleanup problem by causing live snails to cannibalize snail carcasses. To this end, snail carcasses are provided in a trap which is made accessible to live snails for consumption of the snail carcasses. The trap preferably is of a collapsible type or is otherwise provided with first volume permitting entry of live snails into the trap, and is reducible to a second volume insufficient to accommodate live snails, whereby such live snails are crushed. Further live snails are then permitted to cannibalize the crushed snails by restoring the trap to its first volume for entry of the further live snails into the trap. The first volume may be reduced to the second volume against a bias, which is employed to restore the trap to its first volume. Operation of these methods and apparatus may be tied in with a sprinkler system or other apparatus for providing a pressurized medium from time to time.