Abstract: The present invention provides an ultraviolet radiation system which generates UVC radiation with maximal radiation output and little or no degradation in radiation output during operation of the lamps. The system provides UVC radiation at a wavelength of 253.7 nm, which is effective to kill or deactivate pathogens on surfaces irradiated by the emitted UVC radiation and is simultaneously effective to decontaminate air which passes uniformly over the entire length of the UVC lamps. Uniformly flowing air cools the lamps to maximize the conversion efficiency of power input to the lamps to UVC radiation from the lamps, and at the same time decontaminates the flowing air such that air in the room is also decontaminated.

Abstract: A process, apparatus and material composition for forming a coherent refractory mass on a surface wherein one or more non-combustible materials are mixed with one or more metallic combustible powders and an oxidizer, igniting the mixture in a combustion chamber so that the combustible metallic particles react in an exothermic manner with the oxidizer and release sufficient heat to form a coherent mass of material under the action of the heat of combustion, and projecting this mass against the surface so that the mass adheres durably to the surface.

Abstract: A system for forming and applying a coherent refractory mass on the surface of a road wherein one or more non-combustible materials are mixed with one or more metallic combustible powders and an oxidizer, igniting the mixture so that the combustible metallic particles react in an exothermic manner with the oxidizer and release sufficient heat to form a coherent mass under the action of the heat of combustion and projecting this mass against the surface of the road so that the mass adheres durably to the surface of the road.

Abstract: A process and apparatus for forming a coherent refractory mass on the surface of a road wherein one or more non-combustible materials are mixed with one or more metallic combustible powders and an oxidizer, igniting the mixture so that the combustible metallic particles react in an exothermic manner with the oxidizer and release sufficient heat to form a coherent mass under the action of the heat of combustion and projecting this mass against the surface of the road so that the mass adheres durably to the surface of the road.

Abstract: Apparatus for use in a hearing aid wherein a first microphone is connected to the hearing aid case and exposed to free air and a second microphone is connected to the hearing aid case and sealed from free air. The audio inputs from the two microphones are applied to a subtractive circuit so as to cancel any audio signals transmitted through the case of the hearing aid while passing audio signals received by the microphone exposed to free air. In another aspect of the invention, a hearing aid of the behind-the-ear (BTE) type couples sound from the hearing aid loudspeaker through a hollow tube to an inner portion of the ear. A second hollow tube is coupled between a third microphone on the hearing aid case and an outer portion of the ear. Some sound emanating from the tube disposed in the inner ear, exits the ear and is picked up by the second tube and directed to the third microphone. The signal from the third microphone is nulled out by the electronic circuitry of the hearing aid.

Abstract: A process and apparatus for forming a coherent refractory mass on the surface of a road wherein one or more non-combustible materials are mixed with one or more metallic combustible powders and an oxidizer, igniting the mixture so that the combustible metallic particles react in an exothermic manner with the oxidizer and release sufficient heat to form a coherent mass under the action of the heat of combustion and projecting this mass against the surface of the road so that the mass adheres durably to the surface of the road.

Abstract: Apparatus for use in a hearing aid wherein a first microphone is connected to the hearing aid case and exposed to free air and a second microphone is connected to the hearing aid case and sealed from free air. The audio inputs from the two microphones are applied to a subtractive circuit so as to cancel any audio signals transmitted through the case of the hearing aid while passing audio signals received by the microphone exposed to free air.

Abstract: Apparatus for use in a hearing aid wherein a first microphone is connected to the hearing aid case and exposed to free air and a second microphone is connected to the hearing aid case and sealed from free air. The audio inputs from the two microphones are applied to a subtractive circuit so as to cancel any audio signals transmitted through the case of the hearing aid while passing audio signals received by the microphone exposed to free air.

Abstract: A beat frequency interference rejection circuit operative in an electronic security system to inhibit the provision of an alarm indication for the duration of beat interference caused by an interfering transmitter. A high pass filter is employed having a cut-off frequency which substantially blocks all frequency components produced by a resonant tag circuit while passing frequency components caused by the beat processing. The high pass filter signal is processed to produce an inhibit signal to inhibit alarm production in the presence and for the duration of the beat interference.

Abstract: A planar resonant tag circuit especially useful in electronic security systems wherein the value of a circuit component can be electrically and selectively altered by one or more fusible links integrally formed with the planar circuit. At least one fusible link is formed in bridging relationship with one or more turns of a planar inductor and which can be selectively fused by application of an energizing field to activate the resonant circuit or to alter the resonant characteristics of the circuit.

Abstract: An electronic security system adapted for use in a controlled area such as a retail store and employing a multi-frequency resonant tag circuit having distinct frequencies for detection and discrimination. An electromagnetic field is provided within the controlled area at a frequency which is swept through a range including the detection frequency of the resonant tag circuit. In the presence of a tag circuit within the controlled area, pulses are detected by a receiver which includes noise rejection circuitry for discriminating true signals from noise. The noise rejection circuitry is sensitive to expected signals and operative to discriminate true signals from noise on the basis of several different criteria, resulting in substantially reduced false alarm actuation.

Abstract: Real time signal detection circuitry suitable for detection of a resonant tag such as in an electronic security system. True received signals are detected in the presence of high background noise by application of the received signal to a series of pulse height and width threshold detectors which are enabled in a desired sequence. Detection of a series of pulse components comprising an expected signal waveform, having predetermined height and width and occurring in a desired sequence and time relationship provides an alarm indication. A plurality of parallel filters may receive the input signal to produce different waveform configurations for parallel coincidence processing. The circuitry of the invention provides extremely sharp signal discrimination without the use of video delay lines such as used in cross-correlation systems and enables non-repetitive signals to be detected in real time with great accuracy.

Abstract: For use in an electronic security system wherein a resonant tag circuit is sensed to denote an alarm condition, an antenna system which senses the presence of a resonant tag circuit and, upon such sensing, can automatically activate a deactivation field for destruction of the resonant properties of the tag circuit at its sensing frequency and provide an output indication that tag deactivation has been achieved. The antenna system includes a high Q resonant loop antenna for providing a deactivation field, and a coplanar sensing loop antenna isolated from the sensing circuitry during operation of the deactivation antenna.