Abstract: In a fluid composition which is capable of exhibiting a substantial increase in apparent viscosity under the influence of an electric field and which is of the type wherein solid particles of a chemical substance are dispersed in an electrically non-conducting oleaginous vehicle, superior performance results when the chemical substance is a polymer containing acid groups, the polymer having a density not exceeding 1.8 and a specified minimum water absorbency.

Abstract: In a small satellite earth station a directional antenna is rocked about a single axis, corresponding to an oscillatory change in declination, but constant hour angle. The rocking is approximately sinusoidal and has a period of one sidereal day. In a preferred arrangement the antenna is mounted on a rocking axis pivot which is fixed at right angles to, and rotatable for adjustment about, a polar axis member. The polar axis member is set up parallel to the earth's axis and the pivot is rotated about the polar axis member to set the hour angle. The rocking of the antenna is achieved by a crank and tie-rod arrangement driven by a clock motor mounted on the polar axis member. The arrangement is particularly simple and will, when set up, track a synchronous satellite without needing frequent adjustment.

Abstract: A supercritical wing section having a large average leading edge radius of curvature, followed on the upper surface by a reduction in curvature and then a knee, or region of positively increased curvature, at between 3% and 13%, preferably 5% to 10%, chord the region of increased curvature being followed by a region of low curvature extending for 30% to 90% of the chord, whereby in use of the wing at low speeds the peak velocity and peak suction are contained, in use thereof at intermediate speeds local supersonic expansion is minimized, and in use thereof in supercritical conditions a region of high expansion, stabilized over the region of increased curvature, is created.

Abstract: An imaging system in which radiation from a scene is focussed onto a rotor to sweep the image across a detector whose output is used to drive a display such as a cathode ray tube; the rotor has one or more bundles of radiation transmitting fibres. The system may operate in the visible or infra red part of the electromagnetic spectrum.

Abstract: Novel liquid crystal materials are provided having the general formula ##STR1## where A is a 4-alkylphenyl group and B is a 2-(6-alkyl)naphthyl group, or vice versa, wherein the alkyl groups in A and B may be the same or different. These materials have a dielectric anisotropy sign change at moderate frequencies, i.e., in the range 1kHz to 50kHz and are thus useful for twisted nematic device cells of the frequency switching type.

Abstract: An inter-inner-and-outer-clothing overall garment comprising a layer of air permeable cloth treated with oleophobic compound to render a designated outer surface thereof liquid repellant and having activated charcoal approximate a designated inner surface thereof, the garment being the product of a manufacturing process in which only a small number of sizes of said garment are made, the garment having limb members long enough to cover the limbs of the longest limbed subject for that size of garment.

Abstract: An aerodynamic lift mechanism comprises a plurality of aerofoils mounted on two continuous toothed belts which are driven by toothed pulleys. A lever connects each aerofoil to a continuous member which substantially follows the contour of the belts but which is movable relative to the belts. Movement of the continuous member alters the angles of attack of the aerofoils.

Abstract: A flexible aerofoil has a series of members extending chordwise from a structure such as a main spar. The members are rotatably connected at points adjacent the pressure skin and are secured to the pressure skin. Rods, movable in a spanwise direction, act on the members at positions adjacent the suction skin to rotate the members relative to one another and therefore to alter the aerofoil camber.

Abstract: Novel liquid crystal materials which are trans-4-alkylcyclohexane-1-carboxylic acid esters are provided having the general formula: ##STR1## where R is a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms and X is selected from the groups: ##STR2## where A is a cyano group, a normal or branched chain alkyl group, which may also contain a chiral center, containing up to ten carbon atoms or an alkoxy group in which the alkyl group is as defined immediately above, and where Y is a halogen, preferably chlorine, or hydrogen.

Abstract: A microwave integrated circuit component comprises a dielectric substrate layer having an electrically conducting circuit on one face and an electrically conducting ground electrode on the other face. Two electrically conducting strips extend from the ground electrode round the edge of the substrate to lie alongside a part of the circuit. The circuit is contained within a box which carries at least one connector in its side walls for connecting the integrated circuit with external co-axial lines.

Abstract: A liquid crystal display comprises a liquid crystal material layer contained between transparent slides which carry electrodes arranged in lines and columns to form an x, y matrix with x, y intersections. The liquid crystal layer at the intersections are turned on line by line by a blanking voltage, turned off by application of a zero voltage, and held at a threshold voltage at other times. The voltages are applied from a three phase supply by applying one phase to x electrodes a second phase to the y electrodes to maintain a threshold voltage at x, y intersections, and applying the third phase to both x, y electrodes for turning an intersection off. Alternatively the voltages may be applied from a two different frequency waveform supply.

Abstract: Silver and mercury 5-nitrotetrazole salts are prepared by forming an acid solution of a complex of cupric 5-nitrotetrazole with an aliphatic chelating amine and adding to the acid solution a solution of a soluble silver or mercury salt. The silver or mercury 5-nitrotetrazole salt is precipitated and filtered off. The cupric 5-nitrotetrazole amine complex may first be decomposed by reacting with a mixture of nitric acid and a nitrite and the silver or mercury salt solution then added to precipitate the corresponding 5-nitrotetrazole salt. The silver and mercury nitrotetrazole salts are useful as explosives.

Abstract: It has been found that twisted nematic liquid display devices can have a patchy appearance as a result of two problems concerned with degeneracy of the orientation of the molecules in the "on" and "off" states respectively. In the present invention these two problems are solved together by using as the liquid crystal material a naturally optically active material having a molecular helical pitch not less than twice the spacing between the substrates of the device cell, and(1) by treating and later arranging the surfaces of the substrates so that the molecules in the cell liquid crystal layer all lie generally obliquely to the plane of the substrates in the "off" state, or(2) by treating and later arranging the surfaces of the substrates so that the liquid crystal molecules adjacent to one substrate lie in the plane of the substrate but the molecules adjacent to the other substrate lie oblique to that substrate whereby the molecules in the interior of the layer lie slightly oblique to both substrates.

Abstract: In a process for the production of the explosive material 2,2',4,4',6,6'-hexanitrostilbene in which 2,4,6-trinitrotoluene is reacted with an alkali or alkaline earth metal hypochlorite in a solution to precipitate the product, the yield is improved by adding to the mixture, subsequent to commencement of the reaction, a nitrogeneous base. The nitrogeneous base is particularly one having a pKa of 9.25 to 11.25 and an organic amine is especially preferred. The base is added at least 0.5 minute after starting the reaction, and the mixture is stood thereafter for a period which is preferably about 2 hours.

Abstract: An assembly of single-component motion sensors consists of four equinumerous groups of sensors. All the sensors in any one group have their measurement axes parallel and the directions of the measurement axes of the four groups are parallel to the diagonals of a rectangular parallelepiped. The edges of the imaginary parallelepiped are parallel to the coordinate axes relative to which it is desired to measure the components of motion. With two sensors per group the assembly can still give results after any two sensors have failed. It is shown how two non-simultaneous failures, and, in some cases, two simultaneous failures, can be located.

Abstract: A craft, especially an inflatable dinghy, having a manually operable baler ystem comprising a flexible tube passing through the floor of the craft, a funnel mouth to the free end of the tube, and a non-return valve disposed to prevent water entering the craft by the tube, the tube being long enough to permit the funnel to be raised above the normal outside water level when the craft is floating loaded.

Abstract: Liquid crystal compounds are disclosed having the formula ##STR1## where p is an integer having a value from 0 to 5 inclusive. These materials are optically active and cholesterogenic and may be used in an electro-optical display device either on their own or in admixture with nematogenic materials having a formula ##STR2## where i has a value from 0 to 5 inclusive and j is 0 or 1. These last mentioned mixtures may be thermochromic and employed in a temperature sensing device.

Abstract: A helicopter rotor blade is constructed at least in part of composite material of the type in which fibres (such as glass or carbon fibres) are embedded in a matrix. The stiffness in the flapping plane, the lagging plane, or both are modified at one or more positions along the blade to provide advantageous resonance frequencies. Modification of the stiffness is achieved by diverting a substantial number of fibres inwardly towards the relevant spanwise neutral bending plane.

Abstract: A supercritical aerofoil having a large leading edge radius of curvature, a radius of curvature over substantially the whole upper surface appreciably higher than the mean radius over the front half of the lower surface, a concave surface to the rear half of the lower surface, and a thickness/chord ratio of 10- 14%.

Abstract: A field-effect transistor (FET) for use at microwave frequencies has electrodes which act as transmission lines. Gate electrodes can comprise a narrow operative part between the source and drain electrodes which provides gating action, and a gate supply part which lies outside the source and drain electrodes and is connected to the operative part by a plurality of connections distributed along its length. In one form the device can be used as an amplifier and as such is capable of providing higher power handling capacity than conventional FETs, since the device can be extended in size and phase differences between various parts of the device compensate for one another. Other forms and applications are disclosed as a modulator and as a convoluter.