Abstract: An oil and gas well shaped charge perforator capable of providing an exothermic reaction after detonation is provided, comprising a housing, a high explosive, and a reactive liner where the high explosive is positioned between the reactive liner and the housing. The reactive liner is produced from a composition which is capable of sustaining an exothermic reaction during the formation of the cutting jet. The composition may be selected from any known formulation which is suitable for use in an oil and gas well perforator, typically the composition will comprise at least one metal and at least one non-metal, wherein the non-metal is selected from a metal oxide, or any non-metal from Group III or Group IV or at least two metals such as to form an intermetallic reaction. Typically at least one of the metals in the invention may be selected from Al, Ce, Li, Mg, Mo, Ni, Nb, Pb, Pd, Ta, Ti, Zn or Zr.

Abstract: A long range laser illuminator is disclosed that is suitable for providing illumination for camera systems at ranges up to approximately 20 km. The illuminator incorporates a diverger that allows for a compact, low F-number optical arrangement that improves eye safety by reducing the power density across a primary optical element, such as a spherical or parabolic mirror. The diverger may be located at an end of an optical fibre feed, or between a pair of optical fibres. The diverger may incorporate a diffuser, such as a “top hat” diffuser. The optical fibre feeds may be highly multi mode, to provide for a more even illumination. The illuminator incorporates means for altering a focus of the output light beam, to allow an illuminated spot size to be altered. The illuminator is particularly suitable for use at night, where it may be used alongside a camera system.

Abstract: Methods and apparatus for use in quantum key distribution (QKD) are described. A quantum QKD signal is generated at a source and transmitted through a fibre optic network to an endpoint, a key being agreed with communication over a classical QKD channel. The classical QKD channel contains additional information relevant to a network over which keys are distributed, and may be processed at nodes intermediate between the source and the endpoint.

Abstract: A photocell which operates at multiple wavelengths for efficient power generation from broadband incident radiation. According to a preferred embodiment, the photocell is a multi-layer device that includes a first outer layer, a middle layer and an inner layer disposed on a substrate. All three layers are formed from II-VI semiconductor layers. The device is arranged such that the outer layer has a high band gap, the middle layer has a band gap which is less than half the band gap of the outer layer and the inner layer has a band gap which is less than half that of the substrate. Thus, there is a step change in band gap between various layers.

Abstract: A method and system for locating objects in a region having a high degree of multipath susceptibility comprises a plurality of transducers, each being a transmit or receive antenna, and being arranged about the region in known locations, to form a bistatic or multistatic radar, with some embodiments being MIMO systems. Signals transmitted by the transmit antenna(s) are received at each receive antenna and processed to form a set of channel impulse responses, or power delay profiles, representative of the region at a given time. A second set is formed at a different time, and the difference between the two sets is calculated, the difference containing information on movement within the region. The difference may be processed to localize the moving object(s) by graphical means, e.g.

Abstract: A vehicle arresting device comprises a net intended to be laid flat on the ground in the path of an oncoming vehicle to be arrested. Two rows of barbed spikes are attached to the net along its leading edge. When a vehicle runs over the device the spikes lodge in its front tires and the net is caused to wrap around the front wheels, eventually being pulled tight under the vehicle so that the tension in the net prevents further rotation of the wheels and the vehicle is brought to a stop. The net is manufactured such that in its deployed condition it has sufficient lateral stretch to allow it to become fully wrapped around the front wheels before the tension builds up to a level at which there might otherwise be a risk of the spikes being pulled from the tires.

Abstract: This invention relates to the fibre optic distributed acoustic sensing to detect P and S waves in a solid medium. Distributed acoustic sensing can be achieved using an unmodified fibre optic by launching optical pulses into the fibre and detecting radiation which is Rayleigh backscattered there from. By analysing the returns in analysis bins, acoustic disturbances can be detected in a plurality of discrete longitudinal sections of the fibre. The present invention extends such fibre distributed acoustic sensing to detection of S and P waves.

Abstract: A signal generation system suitable for use in a radar system comprises a local oscillator (LO) and an intermediate frequency (IF) oscillator, wherein the IF oscillator is a Direct Digital Synthesizer (DDS), and the LO is a free running oscillator not itself locked to another oscillator but which acts as a clock reference for the DDS and is the highest frequency oscillator in the system. The LO may also act as a reference for a receive chain digitizer. The invention exploits phase noise advantages of a free running oscillator at some distance from the carrier whilst maintaining coherency with other system components. The system typically finds application in FMCW radars.

Abstract: This application relates to methods and apparatus for monitoring hydraulic fracturing during oil/gas well formation. A fibre optic cable (102) deployed down a well bore (106), which may be the well bore in which fracturing is performed, is interrogated to provide a distributed acoustic sensor. Data is sampled from at least one longitudinal sensing portion of the fibre and processed to provide at least fracturing characteristic. The fracturing characteristic may comprise the characteristics of high frequency transients indicative of fracturing events (606). The intensity, frequency, duration and signal evolution of the transients may be monitored to provide the fracturing characteristic. Additionally or alternatively the fracturing characteristic may comprise the longer term acoustic noise generated by fracture fluid flow to the fracture sites. The intensity and frequency of the noise may be analysed to determine the fracturing characteristic. The method allows real-time control of the fracturing process.

Abstract: An optical routing device is described that comprises a semiconductor substrate (52) having at least one optical input (4), a plurality of optical outputs (6,8) and an array of MEMS moveable reflective elements (58;102). The array of moveable reflective elements (58;102) are configurable such that light can be selectively routed from any one optical input (4) to any one of two or more of said plurality of optical outputs (6,8). Light selectively routed from any one optical input to any one of two or more of said plurality of optical outputs (6,8) is guided within a hollow core waveguide (54). In one embodiment, a cross-connect optical matrix switch is described.

Abstract: A multistage flextensional transducer includes at least one inner elongate driver member within and mechanically coupled to an inner shell that is nested within an outer shell; the inner shell comprising a pair of contact portions abutting the driver member and a pair of transmission portions on opposite sides of the inner shell between the contact portions; the outer shell being arranged so that the transmission portions act as bridging driver members between the said inner and outer shells, flexure of the outer shell being driven, on actuation of the transducer, by movement of the bridging driver members. The transducer may act as a push or pull actuator or sensor, may magnify displacement and may employ smart materials as driver members. Also cylindrical modules containing thin flextensional actuators may provide axial displacement in a downhole environment and may move a device axially along a downhole pipe or close a valve opening or inch along the pipe.

Abstract: An apparatus is provided for compensating for the effect of a moving door on a nearby ferromagnetic object detector. The ferromagnetic object detector is of a type to produce a main sensor signal indicative of the presence of a ferromagnetic object in the vicinity of the ferromagnetic object detector. Furthermore, the door is arranged relative to the ferromagnetic object detector such that movement of the door is liable to introduce an undesirable interference signal into the main sensor signal. The apparatus comprises an input (3) for receiving the main sensor signal and a door sensor signal that is responsive to an opening angle of the door. The apparatus also comprises an interference signal estimator (4) for estimating a door-related interference signal in dependence upon the door sensor signal and a model of interference for the door.

Abstract: This invention relates to a pattern recognition correlator in which a serial input data signal is converted into a parallel data signal for correlation with one or more reference data signals. The invention relates to use of a demultiplexer in such a correlation apparatus to reduce the data update rate for the subsequent components. The invention also relates to the use of a series of latch circuits to provide serial to parallel conversion of the input data signal in the electrical domain.

Abstract: A hydrogen generator includes a plurality of fuel sticks each of which includes a hydrogen release compound configured to generate hydrogen by a chemical reaction, a pressure-resistant container configured to store therein the plurality of fuel sticks, and a controller configured to carry out control in such a manner that hydrogen is generated selectively from the plurality of fuel sticks.

Abstract: Improved preconcentrators, particularly MEMs scale preconcentrators which possess a coating comprising polymers of intrinsic microporosity (PIMs). There is further provided devices comprising the preconcentrator, and methods of preparation and use. There is particular benefit directed to the use of a MEMs scale heater coated with the PIMs for use in hand-held or field portable chemical detection devices. The polymer of intrinsic microporosity comprises a polymer, with a monomer repeat unit of Formula I wherein A is one or more optionally substituted aryl, heterocyclic, cycloalkyl or bicycloalkyl rings, ? is greater than 5, preferably 5 to 10000, and X may be selected from CH, CH2, O, S, N or NH.

Abstract: Methods and apparatus for downhole monitoring are provided by interrogating an unmodified optic fibre (102) arranged along the path of a well bore (106) to provide a distributed acoustic sensor and sampling data gathered from a plurality of contiguous sensing portions of the fibre. The sampled data is processed to determine one or more well bore parameters. The well bore parameters may comprise a well condition profile, and may be obtained in response to an acoustic stimulus.

Abstract: Methods of providing duplex free-space optical, communication comprising receiving a time-shift keying (TSK) encoded signal and selectively re-modulating—and optionally retro-reflecting —received TSK pulses so as to transmit an on-off keying (OOK) signal wherein modulation is achieved by operating a micro-opto-electronic mechanical system (MOEMS) device having a oscillation period, the difference in timing between logic 1 and logic 0 pulses of the TSK encoded signal being such that each pulse arrives at a time within a single MOEMS device oscillation period chosen to ensure high or low transmissivity through the MOEMS device independent of incident TSK encoded signal pulse value (0 or 1).

Abstract: A high pressure pump for use in the injection of liquid chemicals into subsea oil or gas wells, and intended to be positioned in the subsea environment adjacent to the wellhead, comprises a piezoelectric actuator (19) for reciprocating a plunger (22) which acts to compress and expand the effective volume of a pumping chamber (29) having a valved inlet (15) connected to a source of the liquid and a valved outlet (16) to lead the liquid to the well. The device has a minimum of moving parts and in particular avoids the need for any rotating parts and attendant high performance bearings and seals.

Abstract: This application describes methods and apparatus for downhole monitoring in real-time. The method involves interrogating an unmodified optic fibre (102) arranged along the path of a well bore (106) to provide a distributed acoustic sensor and sampling data gathered from a plurality of sensing portions of the fibre. The sampled data is then processed to provide a real-time indication of the acoustic signals detected by the sensing portions of the fibre. The real-time indication provides information to an operator or controller of the downwell process with real-time feedback data regarding what is happening during the down-well process which allows the identification of any problems and adjustment of the process parameters.