Abstract: A method and an apparatus for correcting refraction delay errors on curved probes for all ranges using cordic rotation. The angle &phgr; from the normal of an element to the focus is determined as a function of the angle of cordic rotation. Then a delay error correction is indexed using this angle &phgr;. The angular correction method is efficient in that it uses the inherent property of cordic rotation to calculate the only range-dependent variable required for the correction. Thus the additional hardware required to calculate the corrections is minimal, as the remaining correction variables are vector and range independent.

Abstract: The escape of acoustic energy via an opening in a motor housing penetrated by a steering arm is reduced by installing a pair of acoustic seals. The seals have respective membranes which extend across respective portions of the opening in the housing. These membranes are flexible, self-supporting and substantially block the transmission therethrough of acoustic wave energy in the range of 1,000 to 3,000 hertz. The acoustic seals installed in the housing opening, in combination with a vibro-acoustic treatment applied on the inner surface of the motor housing, suppress noise produced by the motor.

Abstract: An aiming device which incorporates into its sight picture a corner shape for aligning with the target, and which aligns two components to form a meaningful shape or image. Meaningful is defined as a shape or image readily recognizable to the one aiming the device, such as a triangle, teardrop, arrowhead, spade shape (as seen in playing cards), rhombus, rectangle, square or any other shape that is easily recognized as a distinctive shape to the person aiming.

Abstract: The vibro-acoustic energy produced by an engine is reduced by shrouding the powerhead with a blanket of material that both damps vibrations and absorbs acoustic wave energy. This vibro-acoustic treatment is applied on the inner surface or surfaces of a motor housing of a propulsion system. The housing is treated by adhering a sheet of acoustic barrier material to the housing inner surface. The acoustic barrier material is designed to block transmission therethrough of a substantial portion of impinging acoustic wave energy in a range from at least 1,000 to 3,000 hertz. The layer of adhesive material has a thickness such that impinging acoustic wave energy in a range of 1,000 to 3,000 hertz is efficiently converted into heat energy. An open-cell foam core laminated to the sheet of acoustic barrier material absorbs the trapped, blocked, acoustic wave energy. The open-cell foam core has an average pore size that is optimized to absorb acoustic wave energy in a range of 1,000 to 3,000 hertz.

Abstract: An apparatus for reinforcing weakened portions of the top guide assembly in a boiling water reactor. The repair apparatus includes a cruciform lattice segment which reinforces the damaged or weakened region of the top guide beam lattice. This cruciform lattice segment is held in place atop the existing top guide with specially designed straps. The cruciform lattice segment and associated straps are arranged so that a beam segment of the cruciform lattice segment bridges the weakened region in the cracked top guide. Thus, the bridging beam segment transmits loads across the weakened region of the top guide. The straps are designed to avoid interference with removal and installation of the fuel assemblies and the control rod blade which is inserted between the fuel assemblies.

Abstract: A computerized imager is programmed with software that allows properly formatted image files (data objects) to be sent to multiple remotely located devices via a network. The imager is programmed with multiple configurable DICOM tasks, one task for each configured remote device. Each task is configured to format image files into DICOM objects acceptable to a particular remote device. Each DICOM object is constructed from image frame data and attribute data. Each DICOM task queries an Attribute Control Engine, which instructs that DICOM task concerning which attributes and what attribute values to include in the DICOM objects being constructed by that task. The Attribute Control Engine in turn reads the attribute information from an Attribute Control File. A respective Attribute Control file is provided for each configured remote device.

Abstract: A propulsion system for a boat has a powerhead or a motor with an exhaust port for exhaust gases. The exhaust gases are exhausted through the propeller hub via an exhaust housing. The exhaust housing is a walled enclosure having an inlet, an internal volume in flow communication with the inlet, and an outlet in flow communication with the internal volume. The exhaust housing further includes hollow structures for dividing a portion of the internal volume into a plurality of flow channels which extend in side-by-side relationship. The transverse dimensions of each flow channel is substantially less than the transverse dimensions of the walled enclosure. The result is that standing waves are shifted to a higher frequency range. The hollow dividing structures have internal volumes which communicate with space external to the exhaust housing via openings in the walled enclosure, which allow the admission of a cooling medium.

Abstract: A modular boat hull including bow and stern sections and at least one center section. Preferably these modular sections are rotomolded thermoplastic parts. These modular hull sections can be quickly assembled by coupling a center section to the bow section and then coupling the stern section to the center section. To increase the length of the hull, additional hull center sections can be added as desired. The modular hull sections are coupled by locking arrangements and then secured by installing a support member which bridges the joints between the gunwale sections of adjacent hull sections. Each modular hull section has a lattice for supporting a deck. The deck can be a single piece installed inside the assembled hull. Alternatively, the deck may be modular.

Abstract: A method and an apparatus for automatically initializing and adjusting the Doppler sample gate position and size settings based on actual vessel image data. A vessel segment search method employs an object search technique based solely on geometric and morphological information in a binarized vessel image obtained from either B-mode or color flow image data. The morphologically best or nearest vessel segment within a target search region in the two-dimensional image is found. The sample gate is placed at or near the center of the targeted vessel segment. The sample gate size is adjusted in relation to the vessel size. Then the best available steering angle that minimizes the Doppler angle is selected.

Abstract: Method and apparatus for automatically detecting and sizing cystic objects in ultrasound imaging. The cystic objects can be automatically detected by the steps of reading an image frame from memory; defining a search region within the image frame or a decimated version of the image frame; binarizing the pixel values within the search region based on a pixel value threshold that is adaptive to local pixel value statistics; morphological filtering the binarized pixel values to eliminate structures smaller than the speckle size; counting the number of continuous objects and keeping track of their area; and rejecting objects that are outside a predetermined size range. Each detected cystic object is automatically sized and graphical information representing the results of the automatic sizing process may be displayed.

Abstract: A method and an apparatus for adaptive wall (high-pass) filtering to remove low-frequency clutter in spectral Doppler I/Q data prior to FFT processing. The I/Q data is passed through a low-pass filter which rejects the flow frequency components above the clutter frequency range. The total power of the low-pass filter output is then computed. A system noise model is used to predict the mean system noise power in the low-pass filter output. The predicted mean noise power provides a noise threshold to gage how much clutter power is present in the current FFT packet. If no significant clutter is present, then wall filter selection logic will automatically select the lowest wall filter cutoff frequency stored in a filter coefficient LUT. If significant clutter power is present in the FFT packet, then the mean and variance of the clutter frequency over the FFT packet are estimated and then input into the filter selection logic, which selects the most suitable filter cutoff for the current clutter signal.

Abstract: A water jet apparatus for propelling a boat. The water jet apparatus has a mechanism for adjusting the size of the outlet of the exit nozzle. The size of the outlet is increased to provide initial thrust and decreased for high speed. A smaller opening is also desirable for low-speed maneuvering. A cone made of resilient material is mounted to the stator hub. A hydraulically driven piston causes the resilient cone to elongate. This changes the shape of the cone and the position of the cone in relation to the exit nozzle outlet. When the resilient cone is elongated, the area of the exit nozzle outlet is decreased.

Abstract: A marine vessel or watercraft in which the power plant or engine is cantilevered off of the inboard face of the transom by a mounting adapter. An inboard engine is attached to the mounting adapter. By this arrangement, the mounting adapter provides cantilevered support to the engine. The engine has at least one exhaust port for engine exhaust gases. The mounting adapter has an exhaust channel in flow communication with an exhaust port of the inboard engine. In addition, the transom has an opening in flow communication with the exhaust channel of the mounting adapter. Thus the passage in the mounting adapter provides a flow path for engine exhaust gases to pass through an opening in the hull. Optionally the exhaust channel in the mounting adapter includes a noise suppression device, e.g., a muffler.

Abstract: A water jet apparatus having a single drive shaft rotatably supported by a pair of bearings installed in an inlet housing. The impeller is securely mounted on a splined end of the drive shaft which extends out of the inlet housing in the aft direction. The drive shaft is not supported by the stator housing, thereby eliminating the need to install bearing inside the stator housing during assembly. Oil seals are arranged between the drive shaft and an inlet housing projection which extends into a cavity formed in the front end of the impeller.

Abstract: A method and an apparatus for imaging blood motion by displaying an enhanced image of the fluctuating speckle pattern. A continuous stream of data frames, each the result of one scan, is available for processing. For each position in the scan plane, a respective time sequence of signal samples is available for processing. The first step in the blood motion image processing is high-pass filtering of this signal. Following the high-pass filter, a speckle signal is formed, e.g., by calculating the squared magnitude (i.e., power) of the high-pass-filtered signal (I/Q or RF). The resulting speckle signal can then undergo a nonlinear amplitude transformation to form a blood motion imaging signal for display.

Abstract: A piezoelectrically active conformal filler material is incorporated in a 1-3, 3-3 or 2-2 piezocomposite structure. The piezoelectrically active conformal filler material has a 0-3 structure and is made of fine piezoelectric ceramic particles surrounded by a conformal polymer matrix. Using such piezocomposite material, the reception and transmission sensitivity (efficiency) of a piezoelectric layer can be improved without any increase in the acoustic impedance of the final piezoelectric layer. The resulting piezocomposite material can be used to fabricate ultrasonic transducer arrays.

Abstract: A water jet apparatus with counter-rotating impellers for propelling a boat. The impellers are coupled by an assembly comprising an impeller shaft secured to a first impeller and a gear train coupling the impeller shaft to a second impeller for counter-rotation. Preferably the gear train comprises one beveled gear secured to the impeller shaft, another beveled gear secured to the second impeller, and a beveled pinion meshed with the first and second beveled gears. The counter-rotating impellers can be driven by a drive shaft coupled to the first impeller for boats having an inboard motor or by a drive shaft coupled to the pinion for boats having an outboard motor.

Abstract: A pump jet having a perforated wear liner inside the rotor housing for altering the spectrum of noise produced by the pump jet. The perforated wear liner is inserted in a circumferential recess formed on the inner surface of the rotor housing and surrounds the rotor tip region. The throughholes or perforations are preferably constant in size and regularly spaced. The perforated wear liner acts as a Helmholtz resonator liner which alters the spectrum of noise emitted from the pump jet during operation. Proper selection of the size, number and spacing of the holes permits the designer to control the specific noise spectrum range that is emitted from the front and rear lobes of the pump jet, thereby altering the hydrodynamic noise field.

Abstract: A boat or other water craft having an inboard engine, an outboard pump jet apparatus and a transom plate on which the pump jet apparatus is pivotably mounted. The boat hull bottom has a water tunnel formed therein, the transom plate has a tube portion in flow communication with the water tunnel, and the pump jet apparatus has an inlet which, in the operating position of the pump jet, is in flow communication with the tube portion of the transom plate. The pump jet apparatus is selectively pivotable between an operating position and a service position. In the service position the pump jet inlet is accessible to a boat occupant to clear debris from the pump jet inlet.

Abstract: A method and an apparatus for wall filtering the receive signal in each receive channel of an ultrasound imaging system prior to analog-to-digital conversion. Large-amplitude echoes corresponding to stationary or very slow-moving tissue are removed before they saturate the inputs to the analog-to-digital converters (ADCs) in the receive channels. By first removing the wall signal, the gain of the TIC amplifier in the receive channel can be increased without saturating the (ADC). This additional amplification will increase the small flow signals, mapping them into higher bits of the ADC, thereby allowing more sensitive detection of weak blood flow in the human body.