Abstract: Apparatus and methods for detecting the presence of an airborne chemical or biological analyte utilise:a substantially gas- and liquid-impermeable container; means for introducing a substantially analyte-free collection liquid into said container; means for rapidly sampling ambient air and transferring said analyte therefrom into said collection liquid, said sampling means comprising an air intake means and and an air venting means; and-means for removing from said container an analyte-enriched collection liquid; wherein said volume of air passes through a substantially horizontal air inlet and upwardly through a substantially vertical collector electrode tube with means for applying an electric field between said tube and a co-axial spiked wire- or rod-shaped discharge electrode.

Abstract: Apparatus and methods for detecting the presence of an airborne chemical or biological analyte utilize: a substantially gas- and liquid-impermeable container; means for introducing a substantially analyte-free collection liquid into said container; means for rapidly sampling ambient air and transferring said analyte therefrom into said collection liquid, said sampling means comprising an air intake means and and an air venting means; and means for removing from said container an analyte-enriched collection liquid; wherein said volume of air passes through a substantially horizontal air inlet and downward through a substantially vertical collector electrode tube with means for applying an electric field between said tube and a co-axial spiked wire- or rod-shaped discharge electrode.

Abstract: A system for selectively obtaining information from a plurality of remotely located data indicating devices includes an interrogate source and a plurality of transponders each associated with a different one of the data indicating devices. The interrogate source transmits an interrogate signal for effecting the readout of a selected indicating device, the interrogate signal being a high frequency carrier amplitude modulated with a pair of low frequency signals to represent an eight bit sync code word, a four bit command word and a twenty-eight bit identification code word for addressing a selected transponder.

Abstract: An optical encoder for indicating revolutions of a shaft includes two phototransistors positioned to be energized concurrently by light from a light source, a barrier rotated by the shaft to shade the photosensors from the light source during a portion of each revolution, and a signal processing circuit which responds to outputs of the photosensors when both are illuminated to provide an unambiguous indication at the end of each revolution of the shaft. The signal processing circuit includes a latch circuit which is set in response to one photosensor, providing an output while the other photosensor is providing its output. The latch circuit is reset when the outputs from both photosensors terminate.

Abstract: A system for providing remote readout of a plurality of groups of data indicating devices including a control unit for each group of data indicating devices for receiving interrogate data signals transmitted over a communication line or RF signal link from an interrogate unit at a central location to the locations of the control units, and for transmitting the interrogate data to transponders associated with the indicating devices over existing electrical power lines to which the control unit and transponders are connected via existing electrical outlets. The transponders are responsive to the interrogate data to generate reply data representing the reading of an associated indicating device for transmission over the electrical power line to the control unit which effects the transmission of the reply data to the central location.