Abstract: A frequency monitoring system comprises a plurality of circuit cards. Each circuit card, such as a primary multiplexer card and a backup or redundant multiplexer card, has an oscillator that provides a reference clock signal. On each circuit card, a respective frequency compare element is configured to receive a clock signal to be measured and to provide a frequency error signal indicating a frequency error of the clock signal relative to an average frequency of a plurality of reference clock signals. Accordingly, the frequency measurements for the circuit cards are based on the same reference frequency (e.g., the average frequency of the reference clock signals from the oscillators).

Abstract: A communication system for propagating time division multiplexing (TDM) fault notifications has a first interworking function (IWF) of a packet network and a second IWF of the packet network. The second IWF detects a TDM fault of a TDM network and transmits continuity check messages (CCMs) to the first IWF. Further, the second IWF controls the CCMs in response to a detection of the TDM fault such that a TDM fault notification is propagated from the second IWF to the first IWF based on the CCMs, and the first IWF propagates the TDM fault notification to a second TDM node via a TDM signal.

Abstract: A power amplifier provides relatively stable quiescent current while maintaining relatively high signal gains and peak to quiescent current ratios. The power amplifier has an input stage and a current mirror stage and incorporates a control transistor between these stages. The control transistor transitions to the triode mode for small inputs and offset voltages thereby reducing the amplifier circuit's gain. However, the control transistor transitions from the triode region to saturation as the input signal becomes larger thereby allowing the amplifier circuit to maintain a relatively high gain for large inputs. Accordingly, better quiescent current characteristics can be obtained without significantly sacrificing performance.

Abstract: A local positioning system uses at least one node to track a location of a mobile tag. The system measures flight times of signals communicated between the node and the tag to determine values indicative of the range of the tag from the node. If desired, the values may be filtered in an effort to increase the accuracy of the range estimation. As an example, a Kalman filtering algorithm may be used. Multiple antennas are used at both the node and the tag to provide more accurate range estimates and to determine when the tag is entering a dead zone where signals are blocked or attenuated by obstacles.

Abstract: A system for monitoring batteries comprises a current control element coupled in parallel to a diode and across a battery. The current control element measures current on the cathode end of the diode. Once the voltage potential reaches a threshold, the current control element routes the current from the cathode end of the diode to the anode end of the diode thereby reducing the voltage potential across the battery terminal. Accordingly, a battery sensing element is prevented from falsely sensing a presence of an operable battery due to leakage current of the diode.

Abstract: A system for achieving bubble stability within a cavitation chamber is provided. The system includes an impeller assembly, the impeller assembly having at least one impeller located within the cavitation chamber. A motor, coupled to the impeller by a drive shaft, rotates the impeller thereby causing bubbles within the cavitation chamber to move toward the impeller's axis of rotation. As a consequence, the bubbles become more stable. Preferably the axis of rotation of the impeller is positioned in a substantially horizontal plane, thus allowing the rotating impeller to counteract the tendency of the bubbles to drift upward and to accumulate on the upper, inner surfaces of the cavitation chamber. The impeller can be rotated continuously throughout the cavitation process or stopped prior to cavitating the bubbles within the cavitation chamber.

Abstract: An eyewear retention device is disclosed that includes a length of resilient cord, such as cabling having a smooth plastic outer sheath, and terminating at each end in a tapered, rubberized retention tubing, and including retention end grommets molded against the ends of the cabling to prevent the slipping off of the retention tubing from the cabling. The combination of the resilient cord and the retention tubing produces a tensioned arc such that in addition to retaining eyeglasses to the vestment of a user when not in use, the retention device forms a suspended arc over the wear's upper torso such that the device does not contact the wear's upper torso or their vestment when donned over a wear's eyes.

Abstract: A method of operating a cavitation system in which the cavitation chamber is separated into at least three distinct chamber volumes by, for example, first fabricating and then installing a pair of gas-tight and liquid-tight seals into the cavitation chamber, is provided. Each chamber volume seal is fabricated from a rigid reflector and a flexible member. During chamber operation, only one of the three volumes contains cavitation fluid, the other two chamber volumes remaining devoid of cavitation fluid. By controlling the pressure within the two unfilled chamber volumes, the rigid reflectors can be used as a means of increasing the static pressure within the fluid-filled chamber volume.

Abstract: An acoustic driver assembly for use with any of a variety of cavitation chamber configurations, including spherical and cylindrical chambers as well as chambers that include at least one flat coupling surface. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass. The end surface of the head mass is shaped to limit the contact area between the head mass of the driver assembly and the cavitation chamber to which the driver is attached, the contact area being limited to a centrally located contact region. The area of contact is controlled by limiting its size and/or shaping its surface.

Abstract: An acoustic driver assembly for use with any of a variety of cavitation chamber configurations, including spherical and cylindrical chambers as well as chambers that include at least one flat coupling surface, is provided. The acoustic driver assembly includes at least one transducer, a head mass and a tail mass. The end surface of the head mass is shaped so that only a ring of contact is made between the outer perimeter of the head mass of the driver assembly and the cavitation chamber to which the driver is attached. The area of the contact ring is controlled by shaping its surface.

Abstract: A method for initiating cavitation within the fluid within a cavitation chamber is provided. In the cavitation preparatory steps, a hydraulically actuated piston is fully retracted and then the cavitation chamber is isolated. The hydraulic piston is then fully extended after which the chamber is partially opened until a predetermined pressure is obtained. After the chamber is once again isolated, cavities are formed and imploded by retracting and then extending the cavitation piston. At least one impeller, located within the cavitation chamber, is rotated in order to stabilize the cavities.

Abstract: A method for initiating cavitation within the fluid within a cavitation chamber is provided. In the cavitation preparatory steps, a hydraulically actuated piston is fully retracted and then the cavitation chamber is isolated. The hydraulic piston is then fully extended after which the chamber is partially opened until a predetermined cavitation piston position is obtained. After the chamber is once again isolated, cavities are formed and imploded by retracting and then extending the cavitation piston. At least one impeller, located within the cavitation chamber, is rotated in order to stabilize the cavities.

Abstract: A method of assembling a port assembly in a cavitation chamber, typically a spherical chamber, is provided. The method is comprised of the steps of boring a port in a cavitation chamber wall, positioning a cone-shaped member within a corresponding cone-shaped surface of a mounting ring, positioning the mounting ring within the port, and locking the mounting ring within the port with a retaining ring. The largest diameter of the cone-shaped member corresponds to the cavitation chamber internal surface. The member can be a window, gas feed-thru, liquid feed-thru, mechanical feed-thru, sensor, sensor coupler, transducer coupler or plug. The member can be secured within the mounting ring with an adhesive. The retaining ring can be coupled to the cavitation chamber external surface with one or more bolts. The port in the cavitation chamber is preferably cone-shaped with the largest diameter of the port corresponding to the cavitation chamber external surface.

Abstract: A method for forming and imploding cavities within a cavitation chamber is provided. The method uses a cavitation piston, coupled to a hydraulically actuated piston, to form the desired cavities during piston retraction and then implode the cavities during piston extension. The cavitation fluid is degassed prior to hydraulically driving cavitation within the chamber. Degassing can be performed within the cavitation chamber or within a separate degassing chamber. In one aspect, a coupling sleeve is interposed between the hydraulic driver and the cavitation chamber. Preferably the coupling sleeve is evacuated. In another aspect, a cavitation fluid circulatory system is coupled to the cavitation chamber. In-line valves on the chamber inlets allow the chamber to be isolated, when desired, from the circulatory system.

Abstract: A method of degassing cavitation fluid using a closed-loop cavitation fluid circulatory system is provided. The procedure is comprised of multiple stages. During the first stage, the cavitation fluid contained within the reservoir is degassed using an attached vacuum system. During the second stage, the cavitation fluid is pumped into the cavitation chamber and cavitated. As a result of the cavitation process, gases dissolved within the cavitation fluid are released. The circulatory system provides a means of pumping the gases from the chamber and the vacuum system provides a means of periodically eliminating the gases from the system. A third stage, although not required, can be used to further eliminate gases dissolved within the cavitation fluid. During the third stage cavities are formed within the cavitation fluid within the chamber using any of a variety of means such as neutron bombardment, laser vaporization or localized heating.

Abstract: A method for forming and imploding stabilized cavities within a cavitation chamber is provided. A hydraulically actuated piston is withdrawn to form the desired cavities and then extended to implode the cavities. At least one impeller is rotated in order to stabilize the cavities, the impeller being located within the cavitation chamber and magnetically coupled to an external drive system.

Abstract: A method for initiating cavitation within the fluid within a cavitation chamber is provided. In the cavitation preparatory steps, a hydraulically actuated piston is fully retracted and then the cavitation chamber is isolated. The hydraulic piston is then fully extended after which the chamber is partially opened until a predetermined cavitation piston position is obtained. After the chamber is once again isolated, cavities are formed and imploded by retracting and then extending the cavitation piston. At least one impeller, located within the cavitation chamber, is rotated in order to stabilize the cavities.