Abstract: An information storage disc, a method of disc manufacture, and a scheme for improved disc surveillance are provided. Generally, the present invention utilizes the geometry and conductivity of a disc's information storage medium to establish an electrically resonant circuit in the disc body. The electrically resonant circuit may be used to detect, locate, and/or monitor the disc. In accordance with 37 CFR 1.72(b), the purpose of this abstract is to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract will not be used for interpreting the scope of the claims.

Abstract: An explosion simulator generates bang, smoke and flash cues. Pressurized gas is released into a shock tube to generate a shock wave and, thereby produce the bang cue. The pressurized gas is released from a gas reservoir into the shock tube through a diaphragm which is broken by a firing pin in response to a control circuit. A smoke powder packet containing a smoke powder is positioned in the shock tube. The pressurized gas travelling in the shock tube bursts the smoke powder packet and the smoke powder is dispersed to produce a smoke cue, or cloud. A flashtube generates the flash cue to illuminate the smoke cloud. An audio/visual explosion simulation system is also disclosed for generating multiple bang, smoke and flash cues from a single shock tube. Immediately prior to generating a bang cue, a gas supply fills a gas reservoir with pressurized gas. A reusable valve opens to release the pressurized gas from the reservoir into the shock tube and closes to seal the reservoir for refilling by the gas supply.

Abstract: A water pump protector which includes electrical circuitry through which an electric motor is energized. The electric motor operates a water pump. The circuitry senses the phase angle between the voltage and the current applied to the electric motor. When the phase angle indicates that the motor is operating without a load, the circuitry deenergizes the electric motor. Thus, the water pump is protected against damage which may occur when the water pump is operated without pumping water.