Abstract: A multichannel surface acoustic wave device is employed to respond to remote channel actuation signals to control the cable television program signals delivered to a subscriber premise.

Abstract: A rub detector for rotating machines such as turbines wherein a grounding arrangement for the turbine rotor is monitored to detect coincidence between a rotor potential discharge and resulting current flow through the grounding arrangement. In the absence of such coincidence, a rub is suspect. In another arrangement in which a grounding strap is utilized, the strap is elevated from ground by means of a diode arrangement and the rotor voltage is monitored and compared with a predetermined reference which may not be exceeded. If the reference potential is attained by the rotor, then the rotor is discharged such that during cyclical operation, a certain discharge waveform is produced, and which waveform is modified in the presence of a rub condition. Means are also provided for imparting a potential to the rotor during initial start-up conditions.

Abstract: A rub between the rotating and stationary parts of a turbine is detected by connecting the rotor to electrical ground and introducing electrical energy into the rotor-ground circuit. A rub between the rotating stationary part modifies the currents in the grounding circuit to an extent that the condition may be detected so as to provide a rub indication. In another embodiment the rotor discharge current in one or more grounding devices normally associated with a turbine is monitored to detect any abnormal condition.

Abstract: Apparatus for detecting bubbles in drilling mud so that appropriate corrective action may take place prior to a possible blowout. A low frequency acoustic field is transmitted through the drilling mud which causes the displacement of any bubbles rising through the mud. A high frequency acoustic doppler detection circuit then detects movement of the bubbles in accordance with their displacement by the low frequency field.

Abstract: A method for detecting and locating defective fuel elements in a liquid cooled nuclear reactor employing a sonic/ultrasonic dual test. In accordance with the invention acoustic transducers, sensitive to a broad range of frequencies ranging from the audio to ultrasonic range, are respectively coupled to the exposed top end plugs of the fuel elements of a nuclear reactor fuel assembly. The respective fuel assemblies are voided of coolant, raising the temperature of the individual elements to a point that will boil any liquid coolant present in a defective fuel tube. The audio output of each transducer is translated into a graphic display identifying the presence and location of defective fuel elements. At prescribed intervals passive acoustic monitoring is interrupted for a pulse-echo attenuation measurement of each element. The respective transducers are sequentially energized, communicating pulsed acoustic energy along the fuel element cladding.

Abstract: The concentration of uranium in a moving stream is determined by agglomerating background microbubbles out of the 6 to 10 micron size range, counting microbubbles in the stream which are about 6 to about 10 microns in size, exposing the stream to a radiation source to cause uranium fission fragments to produce microbubbles, countng microbubbles which are about 6 to about 10 microns in size, and subtracting one count from the other and multiplying by a calibration constant. The subtraction can be performed on an earlier first count so that both counts are made on the same volume. The radiation exposure can be automatically increased when the difference between the first and second counts is low.

Abstract: A method for altering the lateral dimension of the focal zone produced by an integral ultrasonic lens system. The method comprises the steps of removing a volume of lens material from the integral lens system so as to define two separate and distinct remainder volumes on each side of the removed volume. The remainder volumes are then laterally or rotationally displaced relative each other to alter the lateral dimension of the focal zone produced by the integral lens or to produce a discrete focal zone for each of the remaining lens volumes.

Abstract: A non-destructive acoustic method for measuring gas pressure in a hermetically sealed enclosure. In accordance with the method, an acoustic signal is generated and transmitted through the gas medium within the enclosure. The acoustic impedance mismatch between the enclosure and the gas medium is dependent upon the pressure of the gas and correspondingly affects the transmissivity of the acoustic signal. The signal is received after traversing a given travel path through the gas and converted into a corresponding electrical output calibrated against a standard to provide a direct measure of the pressure of the gas within the enclosure. In the preferred arrangement, the enclosure is acoustically damped to substantially dissipate acoustic energy traveling within the enclosure walls.

Abstract: A moisture indicating apparatus for indicating the presence of moisture in a vapor flow confined within a conduit. Sonic energy generated within the conduit is detected at predetermined locations along the conduit by non-intrusively mounted detection devices. The sonic energy is converted into an electrical signal and the magnitude of the electrical signal from each detection device and the time difference therebetween are compared to predetermined magnitude and time-difference standards. If the electrical signals indicate the presence of moisture, responsive action is initiated by a suitable control arrangement connected to the apparatus. In addition to indicating moisture presence, the quality of moisture with the vapor flow is detectable.