Abstract: Disclosed is a method and apparatus for machining a workpiece (2). The method comprises: specifying a path along which a cutting tool (6) is to be moved during machining of the workpiece (2), the path comprising a plurality of segments (26); defining, for each segment (26), an entry point and an entry path (32) from a point remote from the workpiece (2) to that entry point; moving a first cutting tool (6) along the tool path from a first point to a second point and machining the workpiece (2); after the first cutting tool (6) has been moved to the second point, moving the first cutting tool (6) to a point remote from the workpiece (2); moving a second cutting tool (18) along the entry path (32) of the segment (26) that contains the second point, and then from the entry point to the second point.

Abstract: Disclosed is a method and apparatus for machining a workpiece (2). The method comprises specifying a path along which a cutting tool (6) is moved during machining the workpiece (2), the path comprising segments (26); defining, for each segment (26), an exit point on that segment (26); defining, for each segment (26), an exit path (38) from the exit point of that segment (26) to a point remote from the workpiece (2); performing a machining process including moving the cutting tool (6) along the tool path and machining the workpiece (2); and, during the machining process, when one or more criteria are satisfied: interrupting the machining process and, without machining the workpiece (2), moving the cutting tool (6) to the exit point of the current segment (26) and then along the exit path (38) of the current segment (26).

Abstract: A control system for an unmanned vehicle includes a control processing unit which receives input signals from one or more sensors and supplies output signals to one or more actuators. Processing modules are divided into a plurality of successively linked stages. In a first stage, multiple processing modules produce substantially equivalent payload data when operating correctly. Message cryptography units generate cryptographically signed messages containing the payload data. In a second stage, a voting cryptography unit receives and examines the cryptographically signed messages, and applies voting logic to derive a validated payload data for use by the respective processing module of the second stage.

Abstract: A method and apparatus are provided to store transaction records in a retrievable form and to enable subsequent search and retrieval of stored transaction records. Transaction records are captured and then grouped according to predetermined grouping criteria such that they may be indexed to a first level and then efficiently compressed for bulk storage. In the event that records need to be retrieved subsequently, the first level index may be used to select one or more groups of records satisfying first level search criteria and, following retrieval of the selected groups from storage and de-compression, a second level index may be created to enable a more detailed record-level search for matching records in the retrieved groups. Preferably, the same indexing technique is used for both the first and second level of indexing.

Abstract: A method for controlling a digital display device of a head or helmet-mounted display system and a head or helmet-mounted digital display system implementing the method are provided with the aim of controlling the display device in such a way as to reduce the effect of dynamic false contouring on the quality of a displayed image. According to the method, received image data defining brightness levels according to a scheme of light pulse modulation based upon binary-weighted pulse durations are converted into a data defining a sequence of pulses of binary and non-binary weighted duration in which the highest value weighting represents a pulse of a duration less than half the total duration of illumination required during an image refresh period to achieve a pixel at the highest brightness level. In a further embodiment, the weighting of highest value represents a pulse of duration less than one quarter of the duration required for highest pixel brightness.

Abstract: A method and system for calibrating a rotational accelerometer. The method includes attaching a rotational accelerometer to be tested to a plate fitted with and second linear accelerometers and vibrating the plate. Angular acceleration measurements from the rotational accelerometer and linear acceleration measurements from the first and second linear accelerometers are obtained during the vibrating. The linear acceleration measurements are converted into angular acceleration values, and data representing, or usable for, a comparison of the angular acceleration measurements from the rotational accelerometer and the converted angular acceleration values is generated.

Abstract: An optical selector arrangement (22), comprising: a first set of optical ports (30), having a first number of optical ports, the first number being greater than or equal to 2; a second set of optical ports (42), having a second number of optical ports, the second number being greater than the first number; the second set of optical ports being for communicating with the first set of optical ports, a selector interface (40) for the optical selector arrangement, the selector interface comprising the second set of optical ports (42), a part of the optical selector arrangement functioning as a selector (44), the selector being arranged to selectively optically couple the first set of optical ports (30) to a set of ports of the second set of optical ports (42) of the selector interface, the selector (44) being rotatable relative to the selector interface (40) to facilitate the selection by optically aligning the first set of optical ports (30) to the second set of optical ports (42) of the selector interface (40);

Abstract: There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.

Abstract: An electricity generation apparatus is disclosed. An exemplary apparatus includes a plasma container for containing a plasma sustained by radioactive decay. The plasma container has an inlet through which, in use of the apparatus, water can be introduced to the plasma container, and an outlet through which, in use of the apparatus, material can be expelled from the container. The exhausted material can include hydrogen and oxygen resulting from the dissociation of water molecules caused by interactions within the plasma. A separator can separate hydrogen from the material exhausted from the plasma container, which separator is coupled to the outlet, and a generator can generate electricity using the hydrogen as a fuel.

Abstract: The invention relates to Insensitive Munition (IM) energetic materials particularly IM propellant compositions, and yet further to nitrocellulose-free IM propellants. An energetic composition suitable for use as a propellant comprises the following components in the following relative proportions: component A; from 5% to 25% by weight of an IM energetic filler; component B: from 50% to 80% by weight of a highly energetic filler comprising at least one nitramine compound; component C of from 5% to 20% by weight of a binder; and component D of from 3% to 15% by weight of a plasticizer; the percentages by weight of components A, B, C and D together with minor additives, if any, adding to 100%.

Abstract: A heat exchanger assembly (201) comprises: a hot fluid flow channel (210); a cold fluid flow channel (220); and a heat exchanger (230) disposed between the channels. The heat exchanger comprises a heat sink (240) and a thermoelectric device (250). In some embodiments the fluid flow channels (210, 220) may be arranged to provide a cross-flow of the hot and cold fluids.

Abstract: A fabric antenna for telecommunications is disclosed. The fabric antenna comprises a host yarn, which is substantially electrically non-conducting, and an antenna yarn, which is substantially electrically conducting. The host yarn and antenna yarn are knitted together to form a host fabric comprising an antenna grid. The antenna grid comprises a plurality of intersecting antenna tracks formed of antenna yarn. The tracks are separated by regions of the host fabric and are electrically coupled together at the regions where the tracks intersect.

Abstract: A machine is on a first side of a plate (20) and a rod (50) passes along or through the plate (20). The plate (20) is susceptible to vibrations arising from operation of the machine. An active vibration suppressor (60) is mounted on the rod (50), and a controller is configured to control the active vibration suppressor (60) to suppress vibrations of the plate (20).

Abstract: A method for forming a joint between a fiber reinforced composite component and a metallic component and a joint are provided. The metallic component and the composite component each define a joint surface for mating with the joint surface of the other to join the two components together and the composite component defines a free surface opposed to the joint surface thereof. The joint surface of the metallic component defines an array of pins extending therefrom with each pin defining a pin head at an end distal from the joint surface. The method includes the steps of pressing together the joint surfaces of the two components whereby to cause the array of pins to penetrate through the fiber reinforcing material, and modifying the effective cross sectional shape of the pin heads whereby to increase the constraint applied to the composite component against peeling of the composite component from the joint surface of the metallic component.

Abstract: A cartridge casing comprising a casing tube formed substantially of metal with a closed end and an open end. The casing tube bounds at least part of a head cap entered into the open end of the tube. The head cap is fixed relative to the tube. An end wall defines the closed end opposite the head cap end of the cartridge. The end wall comprises a weakened region.

Abstract: Disclosed is a method for delivering a load on-board an aircraft to a target. The method comprises: acquiring a position of the target; acquiring parameter values relating to aircraft maneuverability; acquiring load properties; acquiring parameter values relating to environmental conditions; using the acquired information, determining a position and a velocity value; performing, by the aircraft, the procedure; and, at a point in the procedure that the aircraft has the determined position and its travelling at a velocity equal to the determined velocity value, releasing the load. The determined position and velocity value are such that, were the aircraft to release the load while having the determined position and velocity, the load would travel to be within a predetermined distance of the target. The procedure is such that the aircraft would have the determined position and velocity at some time-step.

Abstract: An aircraft fuselage (4) comprising: an aircraft door or access panel (2) comprising a receiving element (14); and locking apparatus for securing the aircraft door/panel (2) in an opening of aircraft fuselage (4), the locking apparatus comprising: a shaft (8); a mounting member (10) for mounting the shaft (8) to the fuselage (4); securing means (12) fixedly mounted to the shaft (8) and arranged such that rotation of the shaft (8) about its longitudinal axis moves the securing means (12) from being not coupled to a receiving element (14) to being coupled to a receiving element (14) or vice versa; a locking member (52) for coupling to the shaft (8) such that rotation of the shaft (8) causes movement of the locking member (52); and fixing means for fixedly attaching the locking member (52) to the aircraft fuselage (4) thereby preventing rotation of the shaft (8).

Abstract: A robust, durable, easy to use, reusable shipping container is disclosed that is capable of protecting contents from surrounding high temperatures up to 1000 degrees Fahrenheit for a minimum of at least three and a half hours. The container includes an inner chamber surrounded by an outer chamber. A phase change liquid (PCL) is sequestered in a porous support matrix contained in the inner chamber, while the outer chamber is filled with high temperature insulation, forming an outer barrier layer that is designed to reduce heat flux into the inner chamber.

Abstract: A method of producing an assembly tool (60) for assembling an assembly (6), the method comprising: providing at least a portion of a jig frame (62); fixing support plates (65) to the jig frame (62); machining the one or more support plates (65) such that a surface of each of the support plates (65) lies in a common plane (130); positioning the jig frame (62) such that the machined surfaces of the support plates (65) contact with a supporting surface (138); fixing pickup device mounting plates (140a, 140b) to the jig frame (62); machining, with respect to the supporting surface (138), the pickup device mounting plates (140a, 140b) such that a surface of each mounting plate (140a, 40b) has a respective predetermined position and orientation with respect to the supporting surface (138); and fixing, to the machined surfaces of the mounting plates (140a, 140b), a respective pickup device (66-72).

Abstract: A driver circuit for an LED display for switching a light-emitting diode (LED) between a non-luminous state and a luminous state for producing light for a display, the driver circuit comprising an LED, a drive current controller (10) arranged to selectively open and close a drive current flow path (8) through the LED (2) thereby selectively to switch the LED between a non-luminous state and a luminous state, a charge injector unit (13) for inputting charge into the LED to store said charge within the LED via the junction capacitance (3) thereof, a control unit (12) arranged to control the charge injector unit to input said charge into the LED concurrently with the opening of the drive current flow path.