Abstract: A modular fuel assembly has a plurality of axially stacked subassemblies. The stacked subassemblies includes upper and lower subassemblies which incorporate top and bottom nozzles, and a plurality of intermediate subassemblies disposed between the upper and lower subassemblies. Each subassembly includes a plurality of elongated guide thimble segments, a plurality of fuel rod segments and a pair of support grids mounted to the guide thimble segments and supporting the fuel rod segments. The guide thimble segments of the upper and lower subassemblies are releasably mounted to the respective top and bottom nozzles thereof.

Abstract: An active acoustic attenuation system for attenuating tonal blade pass noise in a multi-bladed fan uses a sinusoidal rotational speed signal produced by an accelerometer mounted on the fan as the reference signal for a filtered-X LMS (least mean squarae) adaptive filter controlling a canceling sound generating speaker. The sinusoidal signal is clipped by a zero crossing detector to produce a rectangular wave signal having harmonics which include the fundamental and harmonics of the tonal noise to be eliminated. When the system is used with axial flow fans having a central hub, the speaker is mounted facing the fan and coaxial with the hub. When the fan has a straight discharge conduit, the speaker is no larger in diameter than the fan hub to preclude restricting flow; however, there is no restriction on the size of a speaker facing the fan when it is mounted in the rear wall of a discharge chamber having a lateral discharge opening.

Abstract: A method for determining the concentration of a plurality of combustible gases in a gas stream comprises providing an electrochemical cell apparatus that includes an electrochemical cell in which a cavity is formed having a diffusion limiting port forming the entrance to the cavity. The cell has a process side in flow communication with a portion of the gas stream flowing into the cavity through the port, and a reference side in flow communication with a reference gas. The process side and the reference side of the electrochemical cell are separated by an electrolyte. The potential difference across the cell is adjusted to create a steady state electrical current flow.

Abstract: A circuit breaker with a thermal trip has a calibration opening in the electrically insulating housing through which a tool may be inserted and rotated to distort a support plate on which a bimetal is mounted to calibrate the thermal trip after the circuit breaker has been fully assembled and enclosed within the insulating housing. A tamper indicating seal in the form of a destructible film secured over the calibration opening by an adhesive having an adhesive strength exceeding the tensile strength of the destructible film provides a visual indication of any subsequent attempts to tamper with the calibration setting.

Abstract: In a computer-based motor drive, a microcomputer is responsive to a plurality of input signals drived from the motor AC lines whenever contacts, or pushbuttons, commanding specific control operations to be performed, are closed. In such case, opto-couplers convert such AC voltage into a square pulse train which conveys a succession of digital high and low levels. A reference signal is derived, through an opto-coupler form the AC line, which in its high and low logic form is delayed in relation to the input signal trains. By sampling the input signal upon the occurrence fo a falling edge of the reference signal, then at least after the delay existing between the signals, the validity of the input signal is tested by comparing the two successive samples, thereby insuring a true command addressed to the microcomputer.

Abstract: A pulsed laser arc welding method and apparatus whereby a pulsed input laser beam is generated by a laser pulse generator to cause an ionized plasma cloud to be generated at a worksite. A power supply supplies energy to an arc welding device, which is stored in a capacitor therein. This energy is drawn out of the storage capacitor once the ionized plasma cloud is sufficiently conductive. Control circuitry is provided to control the pulse repetition frequency of the laser pulse generator and to control the energy dissipation from the storage capacitor in the arc welding device.

Abstract: A method for loosening and removing sludge and debris from the vessel of a heat exchanger, such as the secondary side of a nuclear steam generator, is disclosed herein. The method generally comprises the steps of providing a sufficient volume of a liquid, such as water, into the steam generator so that the lower portion which includes the tubesheet is submerged, and then generating a succession of pressure pulses within the water from one or more pressure pulse generators wherein each pressure pulse creates shock waves that exert momentary forces throughout the submerged portion of the generator of a magnitude sufficient to loosen the sludge and debris, but safely below the yield and fatigue limits of the heat exchanger tubes and other components within the generator. The pressure pulses commence as soon as a sufficient amount of water is introduced into the steam generator to submerge the tubesheet, and continue all the way through the draining of the steam generator.

Abstract: A snap action operating mechanism for electrical switches and the like includes a hollow cylindrical housing closed at the ends. A rod extends through one end and is slidable within the housing, while the opposite end of the housing is connected to the switch to be operated. A trip bar projects radially outward in diametrically opposed directions from the rod through longitudinal slots in the housing. A pair of compression springs are disposed within the housing, one on each side of the trip bar. Latch units, each comprising a pair of pivoted latch members, alternately engage opposite ends of the housing to restrain movement of the housing in that direction. Thus, initial longitudinal movement of the rod in the direction of the engaged latch unit results in compression of one of the springs until the trip bar engages a camming surfaces on the engaged latch members, and rotates them clear of the housing. The housing is then accelerated rapidly by the energy stored in the compressed spring.

Abstract: A system and method for controlling the operation of a steam condenser in a power plant which includes a steam turbine, the condense having: a steam flow path including a steam inlet connected to receive turbine exhaust steam from the turbine steam outlet, a condensate outlet and a heat exchange region located between the steam inlet and the condensate outlet; a cooling water flow path having an inlet and an outlet and heat exchange elements for conducting cooling water through the heat exchange region, and a non-condensible product removal path having an inlet communicating with the heat exchange region and an outlet located outside of the heat exchange region.

Abstract: A bi-directional communication and control system includes a common network line over which messages are transmitted in a specific message format and a plurality of hardware based digital IC's which are coupled to the common network line and are arranged to receive messages from and transmit messages to the network line in the specific format is taught. Specifically, a multipurpose two-way communication device is taught which is connected to one of the digital ICs, the device being operable in a master mode in which the device interfaces an external controller to the network line through the connected digital IC so that the external controller can act as the master controller for the plurality of digital ICs coupled to the common network line.

Abstract: Apparatus for lifting and applying torque to an object is disclosed. The apparatus comprises a releasable spring counterbalance which resiliently connects a drive for engaging applying torque to the object to a means for lifting an object, such as a crane. Preferably, a body portion connects the drive and a means for supporting the object. A spring counterbalance reduces the force due to the weight of the object which bears upon the threads when the object is lifted into a position to be torqued. After the threads are initially engaged, the counterbalance is removed and torque applied to the drive means. Torque is transferred through the body portion to the object. Thus, problems associated with the handling of large parts and initially engaging threaded connections are substantially reduced, since the initial engagement takes place under conditions of reduced force.

Abstract: The present invention is a component monitoring system which includes all sensor and plant component monitoring at distributed plant locations close to the sensors which are the source of the signals to be analyzed. Minimally preconditioned analog sensor signals are multiplexed and further conditioned by a sensor signal preprocessor that adjusts the gain and filters the sensor signals before being applied to an analog-to-digital converter controlled by a data acquisition computer. The analog sensor signals are converted into digital samples and stored in a data memory of a digital signal processor using a direct memory access technique. The data acquisition computer also controls the selection of sensors, gain, etc., based on commands from a controller. The digital signal processor, once sufficient sensor data has been collected, performs appropriate processing using known digital signal processing techniques.

Abstract: A thin film electroluminescent edge emitter assembly includes a substrate layer having a configuration to define at least one lateral edge surface and at least one integrated circuit formed therein. The integrated circuit has an input for receiving logic signals, and has an excitation voltage input and a plurality of output leads. The output leads form control electrodes each having an end portion terminating at the substrate lateral edge surface. The integrated circuit is operable to provide an excitation voltage to selected control electrodes in response to preselected logic signals provided to the integrated circuit at the logic signal input. A laminar arrangement formed from a first dielectric layer, a second dielectric layer, a phosphor layer interposed between the first and second dielectric layers and a common electrode layer is disposed on the end portions of the control electrodes.

Abstract: A plasma torch electrode has a copper outer shell on an inner portion of which is provided a more durable composition of a silver alloy by pressing or casting to achieve longer lifetime under arcing conditions in air or oxygen while minimizing the cost of materials and fabrication.

Abstract: Fastener comprises a flat head nut having a specially designed shape and includes a complimentary bolt, for use in a cryogenic environment. Opposed heads of the nut and bolt each have an underside connecting the heads to neck and body portions, respectively, which are of a conical shape and which fit into correspondingly tapered openings of two support members of a superconducting magnetic storage device. The shape of the fastener permits a predetermined contact pressure to be maintained for the support structure as the superconducting magnet is cooled to cryogenic temperatures. The fastener produces a rigid structure to eliminate frictional heating of the magnet. A specially designed tool is provided for torquing the nut and/or the bolt. At least the nut includes three tapered slots in its head portion, and tool having three correspondingly tapered fingers. In this manner, the nut can be sufficiently held, and yet the head of the nut remains flush with the surface of the support member.

Abstract: A clip-connected terminal conductor uses a terminal lug for tightening together with a screw the line cable and the conductor end. A channel is provided in the lug for inserting therein, and guided by lateral wall of the channel, a spring-like member having centrally a boss which engages the aperture of the conductor end. The spring-like member has opposite ledges for clipping with the front and the rear edge of the base of the lug and channel.

Abstract: A transmit pulse delay processor for simulating delayed radar reflections from a target and a method for simulating delayed radar reflections. The pulse delay process utilizes a counter, an adder, a FIFO and a comparator. The pulse delay processor maintains input pulse width and features a programmable delay. The depth selected for the FIFO determines the number of transmit pulses that can be simultaneously delayed. The frequency of the resolution clock clocking the counter and the number of bits in the counter can be selected both to accommodate the length of delay required and to achieve better output pulse accuracy. The pulse delay processor has various applications, but is particularly useful in radar simulation where multiple input pulses must be simultaneously delayed.

Abstract: An AC-to-AC converter operating as a current-source between an AC input line and an AC output line connected to a load, for instance an AC motor, includes three groups of bilateral switches controlled selectively within each group so as to generate a quasi square-wave current in each output phase while establishing a DC voltage between two of the output phases at a time, the third phase being idle, the magnitude of the output voltage being controlled in relation to the firing angle of the switches and the frequency being established by controlling the duration of each square-wave alternance. The duration of such alternances is set to 120 degrees of the output wave, followed and preceded by a 60 degree zero-current period.

Abstract: A frequency division multiplex guardband communication system is provided which increases the communication capability of conventional FDM systems with negligible effect on overall system performance. The additional capacity is achieved through the use of guardbands which lie between the information bands of the FDM. To avoid interfering with recovery of the FDM information, the amount of new signal energy added to the individual guardbands is well below the guardband noise level.

Abstract: A method for the fabrication of a heat transfer member for use with electronic or microwave systems is described. The thermal heat transfer member is a generally planar composite member in which elongated high thermal conductivity fibers are disposed within a matrix material. The method involves molding epoxy matrix material along with conductive graphite fibers and filler material in predetermined geometries. The molded member is then formed in a manner such that the fiber ends are cleanly exposed at the surface of the member in predetermined locations. Metal caps may be formed over the fiber ends to improve heat transfer. Heat is transferred into the member, along the commonly directed fibers, then out of the member at a heat output surface.