Abstract: A linear filament assembly for a halogen cycle incandescent lamp comprises a generally linear filament (usually a coil or coiled coil) supported at opposite ends by substantially rigid conductive leads, a rigid insulating rod, for example of quartz, extending generally parallel to the filament, and a plurality of supports extending between the rod and the filament, each support being fixedly secured to the rod, for example by having a coil part fitting over the rod and also being formed with a coil loosely exbracing the filament. The coils embracing the filament preferably include several closely spaced turns which loosely embrace part of the filament coil, without screwing into or engaging individual pitches of the latter.

Abstract: In a method of constructing a representation of the distribution of absorption in a planar region of a body interpolation is provided, between data signals representing absorption of radiation along parallel paths, to provide signals for an increased number of such paths as required for the processing used. The interpolation is performed by forming differences of second or higher order, subdividing the differences and then combining them by running additions.

Abstract: A radiographic apparatus contains at least one source and at least one detector bank mounted on respective concentric annular rings; the patient's body being disposed inside the smaller ring. The rings are rotated in opposite directions and at such respective angular velocities that the effect of a lateral sweep of the detectors and source across the body is achieved with purely rotational movements. Advantageously, one ring carries two sources disposed diametrically opposite one another and the other ring carries three banks of detectors distributed equi-angularly therearound.

Abstract: A method and apparatus for encoding or decoding data in accordance with a coding format, referred to herein as Y.phi. and which is based on the 3PM coding format. Data encoded in accordance with the Y.phi. format is generated by initially encoding, at a prearranged clocking frequency, binary data in accordance with 3PM format, applying such encoded data to one input terminal of an exclusive OR gate and applying clocking pulses, at the prearranged frequency to the other input terminal. Decoding is similarly achieved by passing the encoded data through an exclusive OR gate. Data encoded according to the Y.phi. format is particularly advantageous on account of the relatively high density of flux transitions which it generates, which may be desirable in certain circumstances particularly if both high and low rate data is to be encoded on the same magnetic tape.

Abstract: A bag holding arrangement for disc record sleeves comprising, a plate whose lower surface is profiled to conform substantially to one side of an open bag. The lower surface of the plate is provided with suction means so that in operation the upper side of the bag is held against the surface, the lower side of the bag being unsupported and allowed to hang naturally. A system incorporating the bag holding arrangement is also described.

Abstract: The antenna comprises an open-mouthed cylindrical cavity 1 defined by side 11 and bottom 12 walls. A conductive coating 5 on an insulative substrate 4 lies on the bottom wall 12. The coating 5 is spaced from the side wall 11 by an annular space 2. A coaxial line 7, 8 feeds microwave energy to the zone between the coating 5 and the wall 12. That zone acts as a radial transmission line which couples the coaxial line to the cavity.

Abstract: When correlating a reference representation with current representations the scales of which are changing, errors occur. In order to reduce the errors, a normal current representation is stored in a store (7), and a scaled current representation is stored in a store (8). Both representations are correlated in a correlator (11) with a normal reference representation stored in a store (9). The reference representation is updated by a control processor unit 5 when the correlation of it with the current representation reaches a peak. Instead of using two current representations a single current representation could be correlated with normal and scaled reference representations.

Abstract: The output of the circuit is connected to the grid of an X-ray tube (X) by a long cable having a large capacitance (C.sub.c). A 25 kHz variable amplitude drive circuit (1) applies a continuous DC regulating voltage to a first rail (RL2) via a first transformer (T1), rectifier (D1, D2) and a filter (F1). A 25 kHz fixed amplitude drive circuit (2) periodically generates a blanking voltage which is applied to a second rail (RL3) via a second transformer (2), rectifier (D3, D4) and a Zener diode (Z1). The first rail (RL2) is coupled to the second rail (RL3) via a clamping diode (D.sub.c) which is reversed biased by the blanking voltage, so that the regulating voltage is overriden. In order to quickly discharge the large capacitance (C.sub.c) to achieve a rapid transition from blanking voltage to regulating voltage, a discharge path is connected across the output, the path including a transistor (T1). A control circuit (3) comprises a capacitor (C2) which stores an actuating voltage (V.sub.

Abstract: An apparatus, for use in an electroplating arrangement, for establishing electrical contact with a metal or metalized cathode plate used in production of a disc record matrix. The apparatus includes an electrically conductive contact member and a clamping means for holding the contact member against a cathode plate supported by the apparatus. The contact member and clamping means are shaped so that electrical contact is established at the periphery only of the cathode plate.

Abstract: The demodulator is especially adapted for a data signal (F'c) that was recorded on tape in the form of a frequency modulated signal together with a reference signal (F'R) of frequency greater than the greatest frequency of the data signal, so that both signals are subject to the same proportional frequency errors. During each cycle of the data signal, a representation of the period of one cycle of the reference signal is measured and stored. Then at the end of each following cycle of the data signal, there is produced a pulse of area dependent on the representation. A filter (LPF) produces a signal representing the area of each pulse averaged over one cycle of the data signal.

Abstract: A lighting unit for a glide path lighting system comprises a light source, a lens, and a colored interference filter part way across the light path between the light source and the lens, arranged so as to produce a light beam having a white part, a colored part and a transition region. The filter is inclined at an angle of approximately 6.degree. to a plane normal to the optical axis of the unit.

Abstract: An electrically conducting cermet comprises a sintered compact of refractory oxide granules such as alumina granules having diameters of from 50 to 800 microns and a conductive network extending through the cermet and provided by a layer of one or more of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel surrounding the individual oxide granules and constituting a volume fraction of 0.04 to 0.2 of the total cermet, wherein particles of one or more of said metals are dispersed within the oxide granules in a volume fraction of 0.01 to 0.15 of the granules, which granules also contain 0.01 to 0.25 percent by weight of magnesium oxide.

Abstract: An ammonia sensitive element which comprises a body of copper phthalocyanine whose electrical resistance varies with the concentration of ammonia gas to which it is exposed. The body of copper phthalocyanine may be supported on a substrate bearing interlaced electrodes.

Abstract: In order to monitor the clearance between turbine blades and the casing of a turbine engine millimetric microwave radiation of wavelength .lambda. is propagated along a waveguide and through an aperture to a turbine blade. The aperture is small in relation to the area of the blade facing the aperture, and the aperture has a spacing of .lambda./4 or less from the blade. A balanced mixer compares the phase of the wave reflected from the blade with a reference pulse to provide a measure of the clearance.Circuits may be provided for monitoring the spacings between blades, and to indicate blades which are damaged.

Abstract: A clutch arrangement for a spool mechanism. The arrangement comprises two clutches, namely an over-running clutch and a constant torque clutch whose respective driven members are connected to the spool bearing and whose driving members are capable of being connected to a drive means. The over-running clutch transmits to the bearing a torque which is substantially greater than the torque applied by the constant torque clutch.

Abstract: In known NMR imaging apparatuses it has been the practice to arrange the G.sub.R field gradient, which rotates in the plane of the examined slice, with a zero crossing substantially in the center of the slice and to demodulate at the Larmor frequency at the zero crossing. It is now proposed to demodulate the detected resonance signals at a frequency which, in the presence of the field gradient, is for a part of the plane lying outside the body slice. This may be by arranging the zero-crossing to be outside the slice. In that case it is preferable that the zero-crossing of G.sub.R lies on a straight line (27) maintained tangential to a circle (28) lying outside the body (23) about an axis (24) through the slice. Control may then be by precalculated coil currents or by precalculating fields at probe positions and adjusting the coil currents to give the expected fields.Alternatively the zero-crossing may be maintained at the center and demodulation may be at a different frequency.

Abstract: Sealing materials for making heat-resistant seals in electrical discharge devices comprise a rare earth oxide, such as lanthanum oxide, and boric oxide, preferably together with minor amounts of phosphorus pentoxide, aluminium oxide and magnesium oxide. Preferred compositions comprise 55 to 95% lanthanum or other oxide, 5 to 45% boric oxide and 0 to 5% phosphorus pentoxide, 0 to 5% aluminium oxide and 0 to 5% magnesium oxide. The compositions can be made by mixing the oxides, or appropriate salts, calcining the mixture at up to 1200.degree. C. and crushing it to a powder. They may be used as frits in a slurry or formed into pressed elements such as discs or washers. Sealing can be accomplished by heating the surfaces to be joined, together with the interposed sealing composition, to a temperature between 1100.degree. and 1650.degree. C.

Abstract: An electron beam tube assembly has a pattern of conductors 20 at least partially provided by being deposited on a major surface of a face plate 16, of the tube 13, the conductors to extend from within the tube 13, at least to an edge 18 of the face plate spaced from the remainder of the tube, and at the edge providing a plurality of exposed, spaced apart ends 22, comprising electrodes, the opposite end of each conductor being coupled by resistive material 28 deposited on the tube to a conductive coating 26 also on the tube, the coating being maintained at a high positive potential with respect to the cathode, in response to the information signals, supplied to the electron beam deflection means 41 and/or to the electron beam modulation means 42, electrical discharges occur to mark an associated sheet 30 of material sensitive to electrical discharges each such electrical discharge being when the electron beam impinges on a conductor.

Abstract: A technique for ensuring the rapid correction of both amplitude and offset errors in the deflectional movement of an electron beam along an X-ray emissive target is disclosed. The movement is monitored at at least two positions during a sweep and differences, between the two movements and a desired movement, at these positions are combined in unequal proportions to produce a corrective servo signal.

Abstract: A CT scanner is described in which the data acquisition components, i.e. the radiation source and detectors, are mounted in an apertured housing which can be deployed generally vertically, for the examination of recumbent patients, or generally horizontally, for the examination of patients seated, or standing, with their torsos upright.