Abstract: A process and apparatus for monitoring the cleaning of a surface (1) by laser irradiation includes illuminating the surface (1) to be cleaned, being cleaned or having been cleaned by ultra-violet irradiation provided either by the cleaning laser or by a further source (5) sufficient to excite into fluorescence contaminants (10, 11) on the surface (1) which fluoresce under ultra-violet irradiation.

Abstract: A method of forming or treating an article or preform (10) and an article or preform made according to the method are provided. The method includes the step of providing around at least part of the article or preform (10) a generally tubular element (14) whose effective cross-section tends to reduce on extension, and applying an extension load to the tubular element (14) thereby to apply a compression load to the exterior of the article or preform to aid consolidation thereof.

Abstract: A novel architecture is described for applying a sum and threshold function to a weightless input string and a weightless threshold string. The sum and threshold function is carried out by distributing the input bits in random manner (12) between a number of sum and threshold devices (14), whose outputs are supplied to a second layer of one or more sum and threshold devices (16).

Abstract: A thermometer code converter for converting weightless binary tuples of 2 or higher dimensional arrays into a thermometer or aggregate code comprises a series of layers (16, 18) each made up of bit manipulation cells (10) which collectively cause set bits to be shifted towards a required bit position. The bit manipulation cells are made up of logic elements (12, 14) and the entire converter may be asynchronous. Also disclosed is a sum and threshold device which employs a thermometer code converter and a bit selector device.

Abstract: A method of manufacturing a stiffened composite structure comprising the steps of: forming the structure around a mandrel tool; using digital camera data to record the positions of desired pad locations on the structure; bonding pads to the structure at the desired locations; curing the pads and structure; forming stiffeners from composite materials including forming a plurality of tabs at points on the stiffener corresponding to the pads on the structure; using a laser theodolite connected to receive the stored information of the pad locations relative to a datum point on the stiffener to locate the stiffener tabs accurately on the pads; and bonding the stiffeners to the structure via the tabs and pads. Preferably, the location tabs and pads are machined off the final stiffened structure after autoclaving.

Abstract: Low-protrusion array antennas enable reception of satellite signals by airliners in flight. Prior systems using a beam normal to an array face required a 70° array tilt for reception from a satellite at 20° elevation (i.e., tilt angle is complementary angle (90°−&bgr;) of satellite angle (&bgr;) of elevation). Compared to that 70° array tilt for reception from a satellite at 20° elevation, disclosed antennas require an array tilt of only 25° (90°−&bgr;−&agr;=25°). This is accomplished by providing a beam at a fixed acute angle (&agr;) to the array face (e.g. 45 degrees). A side-by-side linear array 16 of slotted waveguide radiator columns 18 provides a pencil beam at a fixed acute angle of 45° to array aperture, for example. By action of tilting motor 42 to mechanically tilt the array of slotted waveguides over a range of ±25° from horizontal, the beam can be scanned from 20° elevation to 70° elevation.

Abstract: A single event effect hardening technique for removing glitches in digital logic circuits is disclosed. The noise immune latch circuit includes a first input, a second input, and an output. The noise immune latch circuit includes a first set of two cross-coupled transistors, a second set of two cross-coupled transistors, a first set of isolation transistors, and a second set of isolation transistors. The cross-coupling is accomplished by connecting a gate of each transistor to a drain of another transistor in a same set. The first and second sets of isolation transistors are respectively connected to the first and second sets of cross-coupled transistors such that two inversion paths are formed including the two sets of cross-coupled transistors and the two sets of isolation transistors. The noise immune latch circuit changes from one state to another state only upon having incoming input signals of identical polarity being applied contemporaneously at both the first input and the second input.

Abstract: A device for fixedly securing and releasing items located between counter members and against an abutting member, the device being capable of securing such items to or releasing such items from an end connector and actuating a wedgelock assembly through a single operation.

Abstract: Disclosed is an apparatus and method for inspecting or testing a sample using shearography techniques. A laser shearing interferometer includes: a source of coherent radiation, a line generator producing a line of coherent radiation from said source, a line scanner scans the line of coherent radiation over the sample, a shearing element generates two laterally displaced images of the sample, and phase stepper or ramper steps or ramps the phase of one of the two images. A video camera views images of the sample and provides corresponding video output signals. An image processor receives the video output signals and extracts therefrom the frame rate of the camera in substantially realtime. A signal generator provides the stepper and the line scanner, a signal substantially in phase with the frame rate of the camera, a decoder is used for phase extraction and a vacuum chamber contains the laser shearing interferometer and the sample under test.

Abstract: An electronic control apparatus comprising: a movable control member; a positional servo loop means including at least one motor means and being operable to maintain the position of said control member at any one of a plurality of positions in the range of movement thereof in accordance with a demand signal; force detection means for detecting a force applied to said control member and for providing to said servo loop means a demand signal which varies in accordance with the magnitude of said applied force.

Abstract: In an electric vehicle, the traction motor is driven from a battery by way of a controllable electric power switching arrangement. In normal operation of the switches of the switching arrangement, the power losses or heating of the switches depends upon the power being handled; during hard acceleration the power is high, and at constant speed on level ground the power is relatively small. Thus, the power “dissipated” by the switches varies with time. A cooling system transfers heat from the switching arrangement to ambient. During acceleration, the cooling system may not be able to limit the instantaneous temperature of the switches to the desired value. A phase-change heat “sink” coupled to the switches absorbs heat from the switches during hard acceleration, and returns the heat to the cooling system under more constant-speed conditions.

Abstract: A multi node network communications protocol which provides high information throughput at high efficiency, while also maximizing low probability of detection and interception characteristics by optimizing use of transmitting power and other characteristics including but not limited to modulation method, FEC rate and spread spectrum processing gain. The network is optimized by dividing into sub-networks and optimizing the sub-networks to consider local conditions, thus optimizing the overall network to a level of efficiency not possible from a central control point. A protocol which periodically adapts to changing conditions and allows silent entry and exit of nodes as well as providing locations of all nodes within the network.

Abstract: A dual-radiator whip antenna to operate over a 30 to 450 MHz frequency band includes a high frequency dipole above a low frequency monopole. The outer conductor (30) of a coaxial line is configured to operate as a monopole. Above the upper terminus of the outer conductor, an extension (32a) of the inner conductor (32) is configured as the upper arm of a dipole. An upper length of the outer conductor also functions as the lower dipole arm. With a single antenna port (13), a diplexer and other feed elements separate signals into high and low frequency bands respectively coupled to the dipole and monopole radiators. Increased high frequency range results from positioning of the center of radiation of the dipole above the monopole.

Abstract: Synthesizer radiating systems provide efficient wideband operation with an antenna, such as a loop, which is small relative to operating wavelength. Energy dissipation is substantially reduced by cycling energy back and forth between a high-Q radiator and a storage capacitor. Wideband operation is achieved by actively controlling power switch devices. Dissipation is further reduced during high speed switching by use of sequential switching methods to avoid dissipation of energy capacitively stored in switch capacitances, including switch control circuit capacitance. Systems using multi-segment loop antennas are arranged to match antenna input impedance to switching circuit parameters. Personal transmit/receive systems mounted on a jacket or other clothing for field use are enabled.

Abstract: A baffle (1) for reducing hydraulic ram pressure in a liquid in a tank (5,9) in which it is located resulting from impact of a projectile on an external surface (6,10) of the tank, includes at least two outer walls (2) spaced apart to define therebetween at least one cavity (3) and a compressible gas or gaseous mixture at reduced, atmospheric or enhanced pressure contained in the cavity (3). The baffle outer walls (2) are sufficiently strong to withstand the pressure of the gas or gaseous material contained in the cavity (3) are sufficiently strong to resist the hydrostatic pressure of liquid in a tank (5,9), when the baffle (1) is located in the liquid in the tank (5,9), and are spaced apart by an amount sufficient to provide the cavity with a volume sufficient to allow a shock wave or waves in the liquid resulting from compression of the liquid by impact of a projectile on the tank external surface (6) to be reduced by expansion of the compressed liquid into the cavity volume.

Abstract: A battery equalization circuit for equalizing charge between at least first and second series-connected batteries, where each battery has a positive end and a negative end, with the positive end of the second battery coupled to the negative end of the first battery at a common node, and using: a switching circuit connectable to the positive end of the first battery at a positive node and the negative end of the second battery at a negative node; a transformer having first and second magnetically coupled windings, each with a first end defining a polarity of the winding and a second opposing end; and a transformer reset circuit coupled from the windings of the transformer to the positive and negative nodes. The switching circuit acts to simultaneously couple the first and second windings in parallel with the first and second batteries, respectively, in the same polarity such that a charge is transferred between the first and second batteries as a function of a charge imbalance therebetween.

Abstract: A system for canceling contaminating narrowband interference for a wideband DSSS receiver by weighting a channelized copy of the signal of interest in accordance with the result of a correlation between a narrowband copy of the channelized signal of interest centered around the center frequency of the contaminating narrowband interference and a narrowband copy of a wideband feedback signal centered around the center frequency of the contaminating narrowband interference.

Abstract: The fin 12 has an end plate 16 mounted at its upper end and the end plate covers the upper end of the rudder, so that the rudder 14 seals against the end plate at all rudder deflections. The fin and rudder lift curved slopes are increased by the effect of the end plate 16.

Abstract: A self-contained four-dipole element provides a 360 degree phase-progressive-omnidirectional (PPO) circularly polarized antenna pattern. Via a single signal port, a PPO excitation network incorporated into the element excites the four dipoles at phases differing by successive 90 degree increments. The four-dipole element is adapted for efficiently reproducible fabrication using printed circuit techniques. Antennas employing a stack of the elements provide a hemispherical antenna pattern with PPO circular polarization and a sharp cutoff below horizontal. For GPS reception in Differential GPS aircraft landing applications, a 21 element antenna provides multipath suppression and a unitary phase center enabling avoidance of signal phase discrepancies. More or fewer elements may be employed in other applications.

Abstract: An electric motor vehicle includes an electric motor driving a step-down differential, axles, and drive wheels. An operator control produces torque command signals, which are applied to a controller to command application of electric power to the motor in response to the torque commands, to achieve the desired torque. The low friction of the electric drive, in conjunction with the rotational compliance or imperfect stiffness of the axles, may result in low-frequency surges or jerky motion, especially at low speeds. A damping arrangement includes a differencing circuit coupled between the operator control and the controller, for taking the difference between the operator-commanded torque and a damping torque signal. The damping torque signal is produced by differentiating the electric motor speed to produce a motor-acceleration representative signal.