Abstract: An insect repellent composition for against mosquitoes or other insects that attack man and or warm-blooded animals contains up to 5% by weight of a local anaesthetic selected from the group comprising alkyl p-aminobenzoate (I), arylamide of 2-aminoacetic acid (II), 2-aminoalkyl aryl ether (III), 2-aminoalkyl p-aminobensoate (IV) and mixtures thereof. Particularly preferred is lidocaine and a mixture of lidocaine and prilocaine.

Abstract: A method of making a pressure relief valve includes embedding a pair of opposed plates within a pair of valve lips, forming holes in the lips, inserting springs into the holes into engagement with the plates, and tensioning the springs to constantly urge the lips toward each other.

Abstract: An exhaust system for a gas turbine has a main axial duct which feeds a heat exchanger to make use of the residual heat in the exhaust gases. The heat exchanger may in some circumstances be overloaded so a branch duct is taken from the main duct conventionally by means of a T-junction with a flap valve closing off either the main (axial) outlet or the branch outlet. The branch duct is then taken to an exhaust stack. Turbulence at the T-junction causes poor flow upstream of the junction and corresponding poor turbine performance. The invention provides a junction in which the main axial duct (1) passes smoothly through a bypass chamber (15) which surrounds the axial duct (1). Slots (17) in the axial duct within the chamber (15) permit passage of the exhaust gases to the bypass duct (19). Rotating blade valves (13 and 23) in the two duct outlets control the relative flow of exhaust to heat exchanger and exhaust stack.

Abstract: In a method of forming a matrix addressable display comprising a group of switchable cells, such as liquid crystal cells, having electrodes on each of two parallel plates and thin-film drive transistors disposed on one of the plates, gate resistors are provided by elongate doped polysilicon regions connecting the gate electrodes to address lines. The gate resistors prevent short-circuiting of the address lines in the event of a gate short-circuit occurring in any of the transistors.

Abstract: A mobile decorative part of a Christmas tree ornament is orbited around a stationary decorative part by an electrical motor locked onto the stationary decorative part.

Abstract: An asynchronous transfer mode switching arrangement includes a serial to parallel converter arranged to receive input packets of data, which include routing information, in serial form and convert the packets of data to parallel form. A first random access memory is provided in which each packet of data is entered at an addressed location into the memory, and the address is entered in a respective first-in first-out output queue at the tail. The address at the head of the queue is accessed and the packet of data is read from the first random access memory into a parallel to serial converter and the packet of data is serially delivered to the associated output. The first random access memory and the output queues are controlled by a memory management arrangement to which is connected a broadcast channel routine second random access memory.

Abstract: A tube for interconnecting combustors (11, 12) in a gas turbine combustion system for ignition purposes. The tube comprises three elements: two outer tube sections (15, 17) connected to respective combustors (11, 12) and an inner tube section (16) coupling the two outer sections (15, 17). The ends (20) of the inner tube section (16) protrude somewhat into the outer sections so that air inlet through holes (19) in the outer sections in the vicinity of the two couplings produces cooling air flow (14) adjacent the inner surface of the tube in opposite directions. The bi-directional nature of the air flow (14) substantially prevents any mechanism by which hot combustion gases (10) are carried between the two combustors by the cooling air, thus providing effective tube cooling and prolonging the life of the tube.

Abstract: A method of treating an infection in an individual, by administering an effective dose of bilobalide or of a pharmacologically acceptable derivative thereof. Activity against infection with Pneumocystis carinii has major utility in treating AIDS-associated infections. Bilobalide may be administered systemically or topically in accordance with the invention. For systemic use, oral and parenteral routes of administration may be used.

Abstract: A unit for detecting a moving person or object by means of doppler frequency shift. The unit comprises a microwave circuit board (1) accommodating an oscillator and a mixer, and an antenna board (2) carrying transmit (8) and receive (9) patch arrays. In the assembled unit the two boards (1,2) are disposed adjacent one another. Coupling between the microwave circuit and the antenna arrays is achieved by two slots (6,11) resonant at the oscillator fundamental frequency and formed in a ground plane (5) on the microwave board (1). Feed striplines (7,10,12) on the two boards (1,2) lie orthogonal to the slots (6,11) and are terminated in T-sections (15,14). The stripline/slot arrangement suppresses emission at the oscillator second harmonic frequency. The antenna board (2) has no electrical connection to the microwave circuit, enabling the radiated beam shape to be changed by simply replacing the antenna board with one having a different patch array pattern.

Abstract: A section of a printed circuit board itself is used as an armature for an electrical switch. The armature section of the board is formed by a cutout, and is movable from an initial state to a final state, and is returnable by its inherent resilience to the initial state.

Abstract: A clamp mechanism (19) for clamping the edge (17) of a printed circuit board (11) between the side walls (91a, 91b) of a slot in a wall (93) of an enclosure for housing the board in parallel spaced relationship with other boards. The mechanism (19) comprises an elongated element (21) of resilient material having corrugations (23) whose crests are at regularly spaced positions along its length. An actuator (25) coupled with the elongated element for relative longitudinal motion therewith is provided with riser elements (31b) spaced like the corrugations and positioned so as to move on such relative motion into engagement with the crests to effect the required clamping action. The riser elements (31b) are in the form of rollers (31b) to minimize functional resistance to operation. A spigot arrangement (89, 95) on a lever 75 for operates the mechanism which provides positive locking of the board (11) when clamped.

Abstract: A twin-pocket package provides a cushioned support for articles to be protected from impacts encountered during shipping and handling. Each pocket is formed between a resilient film and a foldable panel. The pockets have mouths that simultaneously expand or contract upon movement of the panel.

Abstract: Liquid crystal polymers, which may be used for optical information storage, either alone or in mixture with other liquid crystals, are of the general formula ##STR1## wherein the mesogenic grouping M has a general structure ##STR2## wherein the rings P and Q are selected from phenyl, trans-cyclohexyl, pyridyl, pyrimidinyl, dioxanyl, and bicyclo (2.2.2) octyl. The rings P and/or Q may carry lateral substituents, preferably Me or F. The general structure of Formula (I) may represent a homopolymer or a copolymer.

Abstract: The invention concerns apparatus for monitoring optical fibers by detecting variations in the polarization of light being transmitted through the fibers. In one embodiment the optical fibre carries non-coherent light and the incoming light is split by a passive splitter (2) connected to a polarization beam splitter (5). Variations in the output of this polarization beam splitter are detected, amplified and filtered so that they can be compared with a preset reference voltage. A counter (12) is used to detect variations. Another embodiment relates to the detection of polarization variations in coherent systems.

Abstract: A display method and apparatus in which a two-dimensional display constituting a perspective view of a three-dimensional surface consists of an array of discrete points appearing to model the surface. An aircraft pilot is provided with a display of ground terrain ahead of his aircraft using stored data representing the terrain.