Abstract: A design of plastics packaged glass optical fibre in which the plastics packaging consists of a urethane acrylate primary coating, a silicone rubber secondary coating and a nylon tertiary coating, the three coatings coacting to provide a pair of substantially decoupled mechanical filters.

Abstract: A system for facilitating leveling of a screed as the screed is being drawn across freshly-poured concrete. The system includes a stationary signal transmitter which is separate from the screed and which generates a planar leveling signal. Mounted on the screed are a pair of leveling signal sensors, each of the sensors being equipped for generating an indication of the level of the screed after receipt of the leveling signal. The sensor are adjustably situated on the screed for proper adjustment and orientation toward the transmitter.

Abstract: A cassette for an inked ribbon has a ribbon storage region, in which the ribbon is stored in tightly packed random folds, between two parallel walls spaced apart by a distance slightly in excess of the width of the ribbon. The storage region is bounded by ridges projecting from one or both walls to retain the ribbon within the storage region. This has the advantage compared with side walls for the storage region of lower frictional constraint on the ribbon thereby allowing the ribbon to be more tightly packed in the storage region.

Abstract: A conferencing module, for conferencing two PCM words uses threshold detectors (7, 8) to assess whether the word represent signals above a preset threshold, plus a comparator (1) to determine the larger signal. One or other is switched by an electronic switch (5) to the output by control logic (4) as follows:(i) if only one PCM word is above the threshold it is switched to the output and the switch setting stored in a memory (6),(ii) if both PCM words are above the threshold, and one is larger than the other, that one is switched to the output and the switch setting noted in the memory,(iii) if neither PCM word is above the threshold, the switch is left as it is, and that fact noted in the memory,(iv) if both PCM words exceed the threshold, and are of equal size, the switch is left as it is, and that fail noted in the memory.

Abstract: To provide an adequate dc supply to the electronics of a telephone, when on hook or off hook, there is a transistor (T2) with its emitter-collector path in one line wire, and a storage capacitor (Cpsu) across the input to the telephones's circuits. This capacitor is charged up and maintains dc supply when the line voltage (at A) falls below a preset level. The base of this transistor is connected via another transistor (T1) to the other line wire. The speech output (V.sub.IN) is connected via an operational amplifier (A) to the base of the second transistor (T2). Hence the dc supply and the speech output are in parallel.

Abstract: The evolution of particulate material from the inner surface of a tubular zirconia susceptor while fibre is drawn from preform is inhibited by providing that surface with a glassy finish by laser-beam fusion.

Abstract: A recirculating filter system for purifying heated liquids, primarily cooking oils or lard, has a sealed filter canister having therein a cotton fiber filter and an upper lid and baffle chamber assembly. An inlet orifice at the bottom of the canister is fed by a pressurized line containing impure oil. An outlet at the top of the canister carries the filtered oil from the baffle chamber to a return line back to the cooking vessel. The cotton fiber filter is contained below the lid and baffle chamber assembly by a retainer pad means forming a second stage to the filtering.

Abstract: A decoder is described for a self-clocking code, e.g. a bi-frequency Manchester code. Transitions are detected in the encoded data and are clocked into a shift register by a clock having a frequency equal to a multiple of the data bit rate. A logic network is connected to the shift register so as to detect combinations of transitions representing encoded data bits "0" and "1". The logic network includes OR gate funnels which detect the transitions in a range of possible positions in the shift register, so as to allow for jitter in the input data signal. The circuit allows encoded data to be correctly decoded in the presence of jitter without the necessity for using a phase-locked loop.

Abstract: A tamper evidencing covering for containers, comprising a hollow container cover and a frangible ring shaped to fit about the cover. The cover includes an external annular retention recess for accommodating the frangible ring, and an annular internal locking bead for affixing the cover to a container. The bead may be segmented, or one or more vertical slots may be provided in the retention recess to relieve the gripping strength of the cover when on a container.

Abstract: The spacing retainer contains spacer elements comprising a multiple number of interconnected angle elements and locking elements. The locking elements are lockingly connected with a first structural steel fabric by means of locking parts at their free ends. A second structural steel fabric is held at a spacing from the first structural steel fabric by means of the series-arranged and side-by-side arranged spacer elements. The spacer elements comprise struts for their reinforcement.

Abstract: An adaptive filter may be realized by weighting the outputs from a tapped delay line. This, however, allows nulls to corrupt a wanted signal spectral region. A fixed (non-adaptive) filter (2) coupled between the signal input and an input of means (3) for summing the weighted outputs serves to allow nulls only to be formed in the skirt region of the fixed filter response thus preserving a wanted signal.

Abstract: An improved brew chamber with filter spacer and support frame for use in an electric coffeemaker. The support frame being resiliently engagable within said brew chamber to be spaced from the chamber bottom whereby filter paper may be received within said brew chamber for receipt therein of a load of fresh ground coffee. During receipt of hot brewing water the filter paper is spaced above the bottom of the brew chamber and is prevented from sagging and clogging the brew chamber so that extracted coffee freely flows through said filter paper and outwardly of the brew chamber through an outlet orifice. The brew chamber and support frame are made of stainless steel and are resiliently engagable whereby used coffee grounds and filter paper may be discarded therefrom without accidental disengagement of the support frame.

Abstract: A data transmission system is described, comprising a plurality of processing nodes (10-13). At any given time, one of the nodes acts as a star coupler, for broadcasting messages to all the other nodes. This node uses a plurality of counters (361-363) to keep track of the amount of available space in the receive buffers (351) of the other nodes. Whenever a message is broadcast, all the counters are decremented. Conversely, whenever an acknowledgement signal is received, indicating that one of the other nodes has removed a message from its buffer, the corresponding counter is incremented. If any of the counters indicates that a buffer is full or nearly full, broadcasting is suspended. If any of the nodes develops a fault, preventing it from removing messages from its buffer, it transmits a constant stream of acknowledgement signals, thereby preventing the corresponding counter from indicating "full" and hence allowing the system to continue running.

Abstract: A surgical tool, for use in hip replacement operations comprises a substantially linear stem which in use seats within a preformed femur cavity. A fixed arm extends medially from an upper portion of the stem and terminates in support for a rotatable cutter. One end of the cutter is received in a seating on the stem below the fixed arm. Ancilliary equipment includes a depth locating tool, so correctly positioning the hip implant in relation to the retained femur neck.

Abstract: A single mode fiber expanded beam termination is formed by fusion splicing an undoped (pure) silica rod to a single mode fiber. The length of the rod controls the expanded beam diameter, and forms a lens on the free end of the undoped silica rod to collimate an output beam.

Abstract: An oil burner of the air atomizing or vaporizing pot type has means to supply oil and combustion air to a combustion chamber adjacent a fluid chamber which receives heat therefrom. Heated fluid is removed from and cooler fluid supplied to the fluid chamber. Control means operate to vary the supply of air and oil dependent on the temperature of the heated fluid leaving the fluid chamber or on the temperature difference between the heated fluid and the cooler fluid.

Abstract: A dual wavelength reflectometer for single mode fibre is provided with separate lasers (5, 6) with emission wavelengths at 1300 and 1550 nm whose outputs are combined using a single mode optical fibre wavelength multiplexer (7) of tapered coupler format. The combined output is fed to a single mode optical fibre beam splitter (9), also of tapered coupler format, which is constructed to act as a 3 dB splitter for both wavelengths. This beam splitter directs light from the lasers into the fibre under test (10) and back-scattered light from the test fibre n to a photodetector (11).

Abstract: A microprogrammed processor in which instructions have alternative fast and slow microprogram sequences. The fast sequences are designed for speed, and can detect exception conditions but do not resolve them. The slow sequences perform all the necessary tests to resolve these conditions. When a fast sequence detects an exception, that sequence is abandoned, and the corresponding slow sequence is run.

Abstract: In an inside tube vapor phase deposition process for the production of doped silica glass by an oxidation reaction for optical fibre manufacture, in particular fluorine doped silica, the oxidation reaction is prevented from occurring until the reactant material, for example silicon tetrachloride and a fluorinating reagent, has been heated to a temperature above that required for the oxidation reaction. This preheating of the reactant material results in the oxidation reaction producing compositions of glasses which are not allowed from thermodynamic considerations at the lower temperature usually employed for the oxidation reaction, for example silica more highly doped with fluorine than hitherto achieved.

Abstract: Apparatus for slicing tobacco bales for conditioning in which the bales are moved from a conveyor (2) onto an adjacent lift device (16) by a first pusher (6), and are then sliced by a slicing blade (20) which is moved horizontally into engagement with the top of the bale and slices the bale while the lift device is dropped slightly to assist in cleaving the bale. The lift is then actuated to raise the bale ready for the next slicing operation, after the previous slice has been ejected by a second pusher (22).