Abstract: A tranverse body is positioned underwater forward of the bow for reducing the surface wave caused by the bow and for increasing the fluid velocity at the forward surface of the bow. The body may be a cylinder, or a lifting body foil, the axis of which is generally parallel to the water surface, bow interface and may be supplied with winglets extending upwardly and inwardly at the edges thereof to form a body similar to a manta ray. The thickness of the body may vary transversely along it so as to counteract the transversely varying surface wave at the bow of the skimmer.

Abstract: A quadrifilar radio frequency antenna intended primarily for receiving signals from an earth orbiting satellite for navigation has four helical wire elements shaped and arranged so as to define a cylindrical envelope. The elements are co-extensive in the axial direction of the envelope and are mounted at their opposite ends in two printed circuit boards lying in spaced apart planes perpendicular to the axis with the end parts of the elements being soldered to conductor tracks on the boards, the tracks constituting impedance elements between the helical elements and between the helical elements and an axially located coaxial feeder. The conductor tracks are such that the effective length of one pair of helical elements and associated impedance elements is greater than that of the other pair and associated impedance elements.

Abstract: The collapsible amplifier stand comprises a pair of U-shaped portions preferably formed out of tubular steel, one of which fits within the other. They are joined at their leg portions by axles having a common axis. Straps are connected between the leg portions to limit the distance between the bight portions when the stand is opened. The bight portions have a pair of straps connected therebetween. The straps are much longer than the maximum distance permitted between the bight portions and thus form a sling for an amplifier to be supported in the sling between the bight portions. The distance between the bight portions and the axles is less than the distance between the ends of the legs and the axles so that the ends of the legs are spaced horizontally outward from the bight portions when the amplifier stand is in use.

Abstract: This invention concerns a method and apparatus of using the relatively thin holographic material of a transmission holographic optical element in such a manner whereby a narrow spectral bandwidth may be achieved. The interference fringe planes oriented through the depth of the material are interrogated by way of the edge of the holographic optical element whereby the holographic optical element is caused to respond, in use, in the manner of a relatively thick reflection holographic optical element of considerable effective thickness. The apparatus takes the form of a narrow bandwidth optical filter which is interrogated by a tightly focussed interrogating beam.

Abstract: Multiple internal reflection, MIR, probes or internal reflection elements, IRE, use the principal of frustrated total internal reflection, FTIR, (also known as attenuated total reflection, ATR,) in infrared spectroscopy, spectrometers, and spectrophotometers. The probes have at least three facets at one end thereof in the form of a regular pyramid preferably at an apex angle of 45.degree.. A modulated oscillating light source is located at one focus of a reflecting ellipsoidal optical element; the other focus is located at one of the facets. Detectors are similarly located with respect to each of the other facets at the focus of reflecting ellipsoidal element with other focus located at the associaed facet. One of the detectors is responsive to a reference wavelength of light, the other to a absorption wavelength of the component of the sample being analyzed.

Abstract: The instrumentation package is transportable to remote sites solely by a light helicopter. Accordingly, three skids are provided, each of which weighs less than 1,200 pounds. An instrument skid comprises a generally, horizontally disposed frame having jacks mounted on it for leveling. Instruments and control elements are also mounted to the frame, preconnected at the factory, and protected from weather. A separate battery skid is provided which is mounted on the instrument skid at the site. A solar array skid, the sloping roof of which comprises solar cells is separately transportable by helicopter to the site and is lowered onto and fastened to the instrument skid. The instrument skid preferably has a self-contained generator mounted thereon when it is transported to the site. An instrument and antenna mounting tower for telemetry, if desired, is broken down and carried within the solar array skid to the site and then mounted on the rear of the instrument skid and tied to the solar array skid.

Abstract: A packing machine for wrapping compressed insulation products in heat sealable plastic film, including a forming tube having product feed means to move or hold the product within it, a former to reconfigure a web of heat sealable plastic film into a longitudinally open tube around the forming tube, a heat welder to close the longitudinal opening and provide a continuous plastic tube, take-off conveyors which receive the plastic tube containing the product at a point downstream of the forming tube and displace the product a preset distance from the forming tube to create a pocket, means to close the plastic tube behind the displaced product and ahead of the next product which is fed into the forming tube as the product is displaced, and means to cut the plastic tube between the two closures so formed, characterised in that air is removed from the pocket before closure by applying vacuum, thereby reducing the time for closing the plastic tube.

Abstract: Messages are transmitted on pairs of frequencies that are orthogonal, that is the frequencies have no least common denominator (are prime to each other). A message is transmitted on the first of the pair of frequencies and, simultaneously, its complement is transmitted on the second of said pair of frequencies. The message is then retransmitted on another pair of orthogonal frequencies. In the second transmission, the message is remapped, such that, adjacent bits in the first transmission are not adjacent in the second transmission and the same bit in the first transmission and the second transmission are not spaced 1/120th of a second apart. Information is collected on the data error rates at each receiver. This information is periodically transmitted to a central frequency controller which collects this error information and determines the error rates on the frequencies being used. A hill-climbing technique is used to choose pairs of frequencies having the lowest current data error rates.

Abstract: An imaging device for processing an optical image in the visible and/or infra-red wavelength bands. An optical image receiving area is divided into four segments and each segment is associated with an optical sensing means in the form of a semiconductor chip comprising a plurality of pixels. Each segment also includes a reflection means for reflecting the particular optical image to the associated optical sensing means. The reflecting means preferably takes the form of a reflecting surface within a cube comprising two prisms. The reflecting surface may be fully reflecting dichroic or holographic. A further optical sensing means in the form of a semiconductor chip is employed to the rear of the image receiving areas and is positioned to sense for small separate segments of the four guarter segments in the center of the overall optical image. All the separate received optical images are processed electronically to produce a composite image.

Abstract: The multi-pass, multi-reflection (MIR) cell used for spectrographic analysis, in a spectrophotometer, for example, is a right circular cylinder having flat end plates perpendicular to its axis. The interior of the cylinder is appropriately coated to reflect the radiation employed and small transparent windows are provided on axis at each end plate. Appropriate input and output tubing is provided. The cell is not much longer than it is in diameter and may have a diameter greater than its length, thus it is either drum or disk-shaped in contrast to the long light pipes of the prior art. The cell is preferably illuminated by a cone of radiation, such as that employed in multiple internal reflection instruments, for liquid analysis employing frustrated total internal reflection in circular rod. A spectrophotometer employing the cell is disclosed.

Abstract: This invention is concerned with a thermal imaging optical system finding utility as an individual weapon sight. The system comprises an infra-red objective lens including a chopper blade together with front and back elements with an adjustable element therebetween. Infra-red radiation is received by the objective lens which also incorporates an internal substantially collimated plane polarized visible light source which illuminates a liquid crystal. The path of the infra-red and visible light which is directed to the liquid crystal cell, is repeatedly interrupted by the chopper blade. Changes in the liquid crystal cell due to the infra-red radiation transmitted by the objective lens are caused to modulate the plane polarized visible light transmitted through the liquid crystal cell to generate a visible image. This image passes through a relay inverting system and is detected by a visible light detector and viewed through an eyepiece.

Abstract: A tooth cleaning tablet, which tablet is such that when it is chewed in a person's mouth it forms a paste and so enables the person to effect a tooth cleaning operation as though using toothpaste.

Abstract: High phosphorus polyphosphides, namely MP.sub.x, where M is an alkali metal (Li, Na, K, Rb, and Cs) or metals mimicking the bonding behavior of an alkali metal, and x=7 to 15 or very much greater than 15 (new forms of phosphorus) are useful semiconductors in their crystalline, polycrystalline and amorphous forms (boules and films). MP.sub.15 appears to have the best properties and KP.sub.15 is the easier to synthesize. P may include other pnictides as well as other trivalent atomic species. Resistance lowering may be accomplished by doping with Ni, Fe, Cr, and other metals having occupied d or f outer electronic levels; or by incorporation of As and other pnictides. Top contacts forming junction devices doped with Ni and employing Ni as a back contact comprise Cu, Al, Mg, Ni, Au, Ag, and Ti. Photovoltaic, photoresistive, and photoluminescent devices are also disclosed. All semiconductor applications appear feasible.

Abstract: A novel torque converter is disclosed which utilizes streamwise vorticity as well as a mean flow within the passageways of the machine to transfer energy efficiency over an extended utility ratio. This is accomplished with novel blade structures utilizing salient edges disposed in part along the mean flow path. Pairs of counter rotating vortices are produced by the impeller blades. The direction of rotation of these vortices is reversed by the turbine blades, efficiently transferring torque from the impeller to the turbine. At speed ratio zero the directions of rotation of the vortices leaving the turbine are again reversed by the stator to impart torque to the stator. This continues until the design speed ratio is achieved. Thereafter, the vortices are guided by the stator passages to the impeller. Below the design speed ratio, the impeller guides the vortices through it to the turbine where their flow is reversed. Above the design speed, the vortices from the stator are reversed by the impeller.

Abstract: The flat undersurface of the turntable is supported on three idler casters. The disc is driven on the periphery by a gear motor which has a drive wheel attached. The direction of rotation of the turntable can be reversed by changing the direction of the motor electrically and by moving the position of the motor so that it tends to drive into the disc as it turns thereby increasing the wheel pressure and friction as the load increases. A spring biases the drive wheel towards this position so that when the power is turned off the motor and gear train acts as a brake. A pair of guide wheels act with the drive wheel to center the turntable. The motor speed is controlled by changing the resistance of a potentiometer on a variable speed motor controller. The potentiometer is converted from a circular motion to a linear motion by a capstan and cable arrangement. A slide moves, when pulled by the stock. The slide pulls a cable that is wrapped around a capstan which is attached to the speed control potentiometer.

Abstract: A two-part optical fibre adapter means suitable for coupling optical signals in electronic shelf assemblies incorporating plug-in circuit boards for high density racked optical systems. One part of the adapter means is mounted in an aperture in a support member and has a thread which is provided for attachment of an optical-fibre connector. The other part incorporates a light-emitting diode and is resiliently mounted by means of a helical spring in an aperture in a further support member. The other part which takes the form of a spigot slidably locates in a bore of the one part and cooperates with a pin of the optical fibre connector which is attached to the one part. A plurality of the optical-fibre adapter means are mounted on an equipment shelf back-plane and a printed circuit board. Use of adapter means of this type eliminates the requirement for inter-link cables between the back-plane and the p.c.b. which have been required hitherto in such equipment-shelf assemblies.

Abstract: An interferometer is provided for producing an interference pattern from light such as laser light which travels along first and second optical paths and at the end of each such path there is a respective fixed mirror for directing light to a common optical path. Means are provided to vary the optical path length of light in the or each first or second optical path to produce an interference pattern in the common optical path, which means comprises a pair of parallel-plane optical flats in accordance with one embodiment of the invention, which are each rotated in an oscillating manner to produce a linearly varying optical path length during rotation. According to another aspect of the invention first detector means are provided for detecting a reference part of the interference pattern produced to derive therefrom a reference signal, and second detector means are provided for receiving the interference pattern to thereby derive signals indicative of successive parts of the interference pattern.

Abstract: Effluent process gases, particularly those employed in the production and processing of solid state electronic components, are cracked to form products having a condensed phase, which may be separated from the flowing process gas. A plasma trap comprises a high frequency coil for producing a plasma therein. The walls of the trap may be cooled and the trap may employ a removable wall on which the cracked product collects. Particular gases that may be treated are arsine, phosphine, disilane, silane, germane, organometallics and gases containing beryllium and boron.

Abstract: The article, typically for use in man-made satellites, has high emissivity and low reflectance in the thermal infra-red wavebands between 6 and 30 microns, and also in the visible wavebands. The article is employed either to cover individual solar-cells, thereby protecting the cells from ionizing radiation and micro-meteoroids, and to protect the adhesive bonding the article to the solar cell from u-v light, or as a thermal control mirror to prevent heat build-up. The article has good emissivity in the thermal waveband regions, so the cell can be maintained at a relatively low temperature.

Abstract: An optical substantially afocal beam expander has a negative lens element spaced from a positive lens element. The lens elements are of different materials with respective coefficients of refractive index change with respect to temperature such that the effect of a temperature change on one element is at least partially compensated by the effect of the temperature change on the other element. The beam expander is therefore substantially athermalised with respect to afocality.