Abstract: A passive acousto-optic modulator for the modulation of a light beam as a function of a variation in air pressure comprising a beam splitter arranged relative to the beam so as to produce a signal beam and reference beam, the beam splitter ideally comprising a flat interface located between two optically transparent mediums such as the end of an optic fiber located within air, the interface being arranged relative to the light modulator such that when the light beam travels through the interface, some of the light beam is able to pass through the interface to form the signal beam, the rest of the light beam being reflected back off the interface to form the reflected reference beam; a light modulator which modulates the signal beam, the light modulator comprising an approximately flat optically reflective surface capable of movement, the reflective surface being located in a position which, at rest is a predetermined distance from the beam splitter and is approximately parallel to and facing the beam splitter

Abstract: A damage sensor for detecting damage within a structure such as aircraft wings or fuselage, or a bridge. The sensor comprises a small piece of a triboluminescent material connected via light guiding fibres or layers to one or more detectors. The sensor may be embedded within the structure or mounted on its surface. Impact of objects on the structure causes a physical damage to the triboluminescent material. Such damage causes light emission which is detected and recorded for later observation. The intensity of emission may be measured to give an indication of amount of damage received by the structure. Several different triboluminescent materials may be arranged in different location within the structure so that location of damage may be detected by a single detector sensitive to the different wavelengths of light emitted by the several materials. Light from the triboluminescent material may be detected directly by the detectors.

Abstract: An electrolyte system suitable for a molten salt electrolyte high temperature battery is described consisting only of a first component which consists of one or more lithium halides and a second component which consists of one or more lithium compounds which are not lithium halides, and is preferably one or more of lithium sulphate, lithium sulphide, lithium metaborate and lithium oxide. A molten salt electrolyte high temperature battery is described incorporating the electrolyte (2), an anode, preferably of lithium or a lithium alloy (3), and a cathode, preferably of iron disulphide (1).

Abstract: A liquid crystal display apparatus includes a first glass substrate with signal electrodes arranged in a striped pattern, a second glass substrate with scanning electrodes arranged in a striped pattern, and a ferroelectric liquid crystal between the first and second glass substrates, the first and second glass substrates facing each other and being fastened so that the signal and scanning electrodes cross each other at right angles. Light blocking members functioning as a black matrix are formed on the first glass substrate so that each light blocking member is placed between adjacent signal electrodes, forms a substantially flat surface with the signal electrodes and is partly buried in the first glass substrate. Metal lines are also buried in the first glass substrate so as to be in contact with the signal electrodes. A similar light blocking member is buried between adjacent scanning electrodes and similar metal lines are arranged on the second glass substrate.

Abstract: The present invention provides novel peptides and vaccines containing them capable of inducing production of antibodies directed against Clostridium perfringens alpha-toxin (CPa) in animals to which they are administered and thereby providing prophylaxis against infection by Clostridium perfringens and/or the alpha-toxin itself. Particularly the present invention provides such a vaccine that is relatively safe and simple to produce. e.g. by genetic engineering means. Preferred peptides comprise theo amino acid sequence of Clostridium perfringens alpha-toxin from amino acid 247 to 370 but lack the epitopes necessary for phospholipase C and/or sphingomyelin hydrolysing activity found between amino acids 1 to 240 of that sequence. Further provided are antisera and antibodies raised to the peptides and vaccines of the present invention, and particularly monoclonal antibodies and hybridoma cell lines for their production.

Abstract: An electro-optic color device including a layer of polymer dispersed liquid crystal (7), with polarizers on either side (9,10), at least one being colored. By applying a voltage across the polymer dispersed liquid crystal cell (PDLC), the cell is switched from a scattering to a non-scattering state or vice-versa, and the color of the transmitted light is controlled. Applications include membrane switches.

Abstract: The invention concerns a surface stabilized ferroelectric liquid crystal (SSFLC) display devices. Displays are formed by cells containing a thin layer, e.g. 2 .mu.m thick, of smectic liquid crystal material. The cell walls are surface treated and carry e.g. row and column electrodes forming an x,y matrix of addressable display elements or pixels. These devices can show bistability and switch between their two stable state on application of a dc pulse of appropriate polarity, amplitude and width. In this invention the device is addressed by first preconditioning the liquid crystal material at each pixel by applying one of two different levels of ac bias, thereby changing the switching characteristics of the material, and second by a switching with application of a switching pulse. This results in pixels that have received the first of the ac bias levels switching whilst the other pixels do not switch. The two levels of ac bias may be applied e.g.

Abstract: A sensor system in an interferometric arrangement has a sensor arm and a reference arm. The reference arm is in a stable environment and the sensor arm is arranged to be subject to variations in strain and/or temperature. Radiation from a broadband source propagates through the arrangement and a broadband interferogram is generated as an air gap is scanned. The interferogram is recorded on an oscilloscope and analyzed using signal processing software on a computer. From the analysis the changes in group delay and optical dispersion of the light in the sensor arm due to strain and temperature changes is measured, and values for the strain and/or temperature changes calculated. A narrowband light source may be used for accurate calibration of path length differences during scanning. The strain and temperature on the sensor arm may be calibrated or tested using clamps and a thermal enclosure.

Abstract: A cathode ray tube comprising a cathode (K) for emitting a beam of electrons; a grid (G) for controlling the intensity of the beam; three or more anodes (A1, A3, A4); a control for varying the potential of at least one of the anodes (A3) for focusing the beam to form a spot on a screen; and an additional, dynamic focus electrode (A2) maintained generally at a potential close to the cathode/grid potential. Suitable structure may be included for applying to said dynamic focus electrode a high frequency signal to provide a rapid focus control. Said dynamic focus electrode may comprise a plurality of circumferentially disposed segments and including applying a separate high voltage to each segment thus allowing the possibility of creating a quadruple action in conjunction with at least one adjacent electrode, said segments covered with a deposited high-resistance conducting film to prevent charging effects.

Abstract: A signal routing device (10) incorporates a multimode beamsplitter waveguide (20) connected by a set of parallel relay waveguides (22) to a multimode recombiner waveguide (24). Each relay waveguide (22) contains a respective electro-optic phase shifter (36). Sets of input and output waveguides (18, 28) are connected to the beamsplitter and recombiner waveguides (20, 24) respectively. The input and output waveguides (18, 28) are periodically spaced at off-center positions across the respective multimode waveguide transverse cross-section associated therewith. Radiation in any one of the input waveguides (18) is distributed between the relay waveguides (22) by virtue of modal dispersion in the beamsplitter waveguide (20). The phase shifters (36) apply a set of phase shifts to the distributed radiation. Modal dispersion in the recombiner waveguide (24) results in the phase shifted radiation providing a non-zero input to one or more of the output waveguides (28).

Abstract: A gravity operated shell feed apparatus for a turret-mounted gun comprises two stacks of downwardly sloping magazine racks, from the lower ends of which shell may be singly released to roll into an appropriately positioned collection tray which is then angularly deflected in a vertical plane so as to transfer the shell to a ramming tray for delivery to a ramming position at the gun, the whole sequence being manually controlled by means of a single operating lever.The apparatus is designed for a fixed loading position thereby avoiding the necessity of sweeping the feed apparatus at high speed through a large volume of turret space, and using instead the elevating gear of the gun to sweep the balanced elevating mass through a smaller turret volume at a proportionately lower speed, in a region less hazardous to the gun crew.

Abstract: Tellurium and selenium alkyls are purified by thermal dissociation of the adduct of the compound with a Group IB or IIB metal.

Abstract: A method, device, and material for providing a fast switching liquid crystal display employs the ferro electric effect of chiral smectic liquid crystal material. To provide a uniform appearance the liquid crystal material is arranged to have a long cholesteric pitch at a temperature close to a smectic/cholesteric phase transistion temperature. This long cholesteric pitch allows liquid crystal molecules to cool from the cholesteric to smectic phase with a uniform alignment. The smectic material is contained in a cell between walls (2, 3) bearing electrodes (5, 6) and surface treated to provide homogeneous alignment of liquid crystal material (7).

Abstract: A drain valve for a vessel having a bilge (4) which is elevated above external water level when the vessel is floating in unladen condition. The valve comprises a drain cylinder (1) located in a drain port (2) and attached at its upper end to the bilge; the cylinder axially containing a spindle bearing (14) in which is slideably located a spindle (20) of a buoyant closure member (32) engageable with the lower end of the cylinder. Opening and closing of the valve is controlled by the pressure differential existing between external and internal water levels.

Abstract: A curable thermosetting prepolymerized imide resin composition is prepared by chemically reacting, at a temperature below 150.degree. C., a liquid mixture of a carboxy-terminated polybutadiene/acrylonitrile (CTBN) and a co-reactant containing at least one N,N'-bisimide of an unsaturated carboxylic acid of general formula (I) ##STR1## where B represents a divalent radical containing a carbon-carbon double bond and A represents a divalent radical having at least two carbon atoms, at least one monoimide, and at least one organic hydrazide, to yield a curable thermosetting prepolymerized imide resin composition containing copolymerized CTBN and co-reactant. A resin composition prepared by this method may be cured at a temperature between 100.degree. C. and 350.degree. C. to yield a fully cross-linked polymimide matrix containing a dispersion of phase-separated solid particles of copolymerized CTBN and co-reagent, said matrix having a lap shear strength at 20.degree. C.

Abstract: A halide based process for the removal of surface oxidation and corrosion contamination from metallic articles especially cracked superalloy turbine components, which utilizes a pulsed pressure cycle. Preferably the cycle is established by alternate evacuation and replenishment. A cycle operating at 150 torr or less and utilizing CHF.sub.3 hydrogen and inert gas as atmosphere is described. The evacuation phase of each cycle should preferably reach 20 torr or less. The process is also applicable to etching for detection of near-surface flaws.

Abstract: In a control system monitor signals are received from points in the controlled system. The signals are band limited by filters respectively to provide matched band limited signals for correlation by comparison logic to provide failure flag output. The invention is based on the realization that signals in different parts of the system should correlate if suitably conditioned, and that the result of the correlation is indicative of performance.

Abstract: Compounds of the formulaR.sup.1 --Q.sup.1 --(CH.sub.2).sub.m --(COO).sub.n --(CH.sub.2).sub.p --Q.sup.2 --R.sup.2whereinR.sup.1 and R.sup.2 are each independently alkyl or alkoxy each of 1-12 C atoms, F, Cl, Br, CN or --Q.sup.3 --R.sup.3, or one of R.sup.1 and R.sup.2 can also be H;Q.sup.1, Q.sup.2 and Q.sup.3 are each independently 1,4-phenylene, 1,4-cyclohexylene, 1,4-bicyclo(2,2,2)-octylene or 1,3-dioxane-2,5-diyl, each of which is unsubstituted or substituted by 1-4 fluorine, chlorine or bromine atoms;R.sup.3 is alkyl or alkoxy each of 1-8 C atoms, H, F, Cl, Br or CN;m is 1, 2, 3, 4, 5 or 6; n is 0 or 1; and p is 0, 1, 2, 3, 4 or 5; the sum of (m+p) being 2, 4 or 6 and the sum of (m+n+p) being at least 3;but with the proviso that Q.sup.3 is unsubstituted 1,4-phenylene or 1,4-phenylene substituted by a fluorine, chlorine or bromine atom, only when n=1 or (m+p)=6 or at least one of R.sup.1 or R.sup.3 is F, Cl or Br or none of R.sup.1 to R.sup.3 is CN or two of the radicals R.sup.1 to R.sup.

Abstract: A six-port reflectometer includes first, second and third forward directional couplers to transmit power from a source for reflection at a measurement port. The couplers also divert incident and reflected wave samples for subsequent measurements. A fourth forward directional coupler receives samples of incident and reflected waves from the second coupler, the reflected waves being received directly and the incident waves via a waveguide appropriate to equalize wave path lengths. The first coupler is connected to a matched load and the third coupler to a short circuit. The first coupler may be a 6 dB device and the second, third and fourth couplers 3 dB devices. Power detectors are connected to the first, third and fourth couplers. The reflectometer has the band-width of its components.

Abstract: A method of producing an adduct of an organometallic compound M.sup.1 (R.sup.1).sub.x, where M.sup.1 is a Group II or Group III metallic element and R.sup.1).sub.x represents a plurality of organic radicals, which may be the same or different, x being an integer equal to the valency of M.sup.1, comprises electrolysing, using a sacrificial anode of the metal M.sup.1, a solution containing components A, B and C as follows:A: a magnesium compound MgR.sub.2.sup.1 ;B: a readily ionizable support electrolyte providing relatively large anions and cations;C: a polar aprotic liquid which is a solvent for both components A and B; the metal M.sup.1 being selected from the group consisting of: indium, gallium, cadmium.