Abstract: A process of collecting and manipulating data to measure the gap between structural components of a piece of equipment or a system is disclosed and claimed. The technique uses ultrasonic zero degree longitudinal waveforms to measure the gap. The technique subtracts the average of two adjacent waveforms from the waveform being processed to remove data from reflections from the components to reveal the reflections generated by the gap.

Abstract: A method validating a particulate monitoring device includes generating a final gas stream having a particulate material concentration that corresponds to a target particulate material concentration, using the particulate monitoring device to measure the particulate material concentration in the final gas stream, and evaluating an accuracy of the particulate monitoring device based on a comparison of the particulate concentration in the final gas stream that was measured by the particulate monitoring device with the target particulate material concentration.

Abstract: A self cleaning system for a swim spa and a hot tub including a container for holding water having a weight bearing floor and sides. A basin may be positioned in the floor of the container and is integral with the container. A perforated cover may be set into the basin. A suctioning means can be positioned in the basin under the perforated cover to allow for the suctioning of water and debris through the perforated cover.

Abstract: Methods and systems for producing a change in a medium. A first method and system (1) place in a vicinity of the medium at least one upconverter including a gas for plasma ignition, with the upconverter being configured, upon exposure to initiation energy, to generate light for emission into the medium, and (2) apply the initiation energy from an energy source including the first wavelength ?1 to the medium, wherein the emitted light directly or indirectly produces the change in the medium. A second method and system (1) place in a vicinity of the medium an agent receptive to microwave radiation or radiofrequency radiation, and (2) apply as an initiation energy the microwave radiation or radiofrequency radiation by which the agent directly or indirectly generates emitted light in the infrared, visible, or ultraviolet range to produce at least one of physical and biological changes in the medium.

Abstract: A self cleaning system for a swim spa and a hot tub including a container for holding water having a weight bearing floor and sides. A basin may be positioned in the floor of the container and is integral with the container. A perforated cover may be set into the basin. A suctioning means can be positioned in the basin under the perforated cover to allow for the suctioning of water and debris through the perforated cover.

Abstract: A method of estimating the volume flow in a vessel utilizing ultrasound techniques including the steps of imaging the vessel utilizing an ultrasonic transducer array so as to produce fluid velocity information for the vessel, the plane formed by the beams emitted by the transducers having a direction which is offset from an axis of the vessel such that the beam plane forms an elliptical section within the vessel, and utilizing the velocity information for points within the vessel and the elliptical section to calculate a mean velocity for the fluid flow through the elliptical section. The improvement of the volume flow estimation is achieved by utilizing average velocity information and Doppler signal power, and mean velocity calculation based on a weighted summation of the velocity values a multiple measurement points with weighting factors determined by the Doppler signal power at the measurement points.

Abstract: The disclosure describes a multi-stage phase comparator and a phase-locked loop incorporating such a comparator. The comparator measures a phase difference between a reference signal and an output signal using a periodic clock. The comparator is a two stage comparator comprising a fine and coarse comparator. The coarse comparator measures the number of full clock periods between a transition of the reference signal and the output signal. The fine comparator comprises a delay line generator that generates a plurality of delayed clocks. The delayed clocks are used to over sample the reference signal to determine a fine phase difference representing a remaining fraction of the clock period, between transitions of the reference and output signals. A phase locked loop using the multi-stage comparator allows for more accurate phase locking.

Abstract: An apparatus for determining both the axial and angular positions of a defect in a tube wall. The apparatus includes a probe head positioned at the end of an elongated probe carrier having an imbedded orientation indicator. In the preferred embodiment, an encoder measures the angular orientation of the probe head when facing the defect relative to the angular orientation of the carrier and a photodetector and reflective strip measure the angular orientation of the carrier relative to a known orientation. A data processor uses this data to calculate the angular orientation of the probe head and the location of the tube defect.