Abstract: A process of production of a monolithic article from a web of fibres of oriented polypropylene polymer, comprising the steps of subjecting the web to elevated temperature and pressure sufficient to melt a proportion of the polymer and compact it, and then cooling the compacted web, wherein an accelerated rate of cooling is employed down to 100° C. The process is of particular benefit when the weight average molecular weight (Mw) of the fibres is 250,000 or below. The resultant articles have good stiffness and strength, yet with reasonable ductility. Similar articles cooled slowly are brittle.

Abstract: A process for the production of a polymeric article comprises the steps of: (a) forming a ply having successive layers, namely (ii) a first layer made up of strands of an oriented polymeric material; (ii) a second layer of a polymeric material; (iii) a third layer made up of strands of an oriented polymeric material, wherein the second layer has a lower peak melting temperature than that of the first and third layers; (b) subjecting the ply to conditions of time, temperature and pressure sufficient to melt a proportion of the first layer, to melt the second layer entirely, and to melt a proportion of the third layer; and to compact the ply; and (c) cooling the compacted ply. The resultant articles have good mechanical properties yet may be made at lower compaction temperatures than articles not employing the second layer, leading to a more controllable manufacturing process.

Abstract: A polyolefin plaque is made by hot compaction of an assembly of fibres of the oriented polymer. It has been found to be beneficial to subject the fibres to a prior crosslinking process. Hot compaction is then less temperature-sensitive and produces plaques with excellent hot strength properties. Preferably the fibres have been subjected to prior stages of irradiation and annealing, both in a non-oxidising environment, for example acetylene.

Abstract: A composite material comprising an inorganic filler material and a oriented fibrous polymeric material characterised in that the fibrous material has areas of adjacent fibres fused together to form a network or continuous matrix while retaining oriented fibrous structure in the composite.

Abstract: A process for production of a monolithic article from a web of fibres of oriented polypropylene homopolymer or copolymer having a weight average molecular weight (Mw) of at least 250,000 includes the steps of subjecting the web to elevated temperature and pressure sufficient to melt a proportion of the polymer and compact it, and thereby yielding an oriented phase and a matrix phase, and effecting a heat treatment selected from (i) subjecting the compacted web to a retarded rate of cooling down to a lower temperature at or below the temperature a which the recrystallisation of the matrix is complete; and (ii) annealing the compacted web at an annealing temperature within 15° C. of the temperature at which the matrix phase is completely melted. The resultant articles have good stiffness and strength, and acceptable ductility, yet corresponding articles made with polypropylene of lower Mw are brittle.

Abstract: A stair chair is provided and includes a seat 30, a backrest 34, a foot rest 32, upper handles 84 and lower handles 82. Three wheels 62 are mounted at each side of the chair. The wheels are pivotal about their own axis and also a common axis. Rotation about the common axis can be braked or locked. The chair can be lowered downstairs with a person pulling on the upper handle 84 and another person pushing on the lower handles 82 in order to slow movement of the chair down the stairs.

Abstract: A stair chair is provided and includes a seat 30, a backrest 34, a foot rest 32, upper handles 84 and lower handles 82. Three wheels 62 are mounted at each side of the chair. The wheels are pivotal about their own axis and also a common axis. Rotation about the common axis can be braked or locked. The chair can be lowered downstairs with a person pulling on the upper handle 84 and another person pushing on the lower handles 82 in order to slow movement of the chair down the stairs.

Abstract: A stair chair is provided and includes a seat 30, a backrest 34, a foot rest 32, upper handles 84 and lower handles 82. Three wheels 62 are mounted at each side of the chair. The wheels are pivotal about their own axis and also a common axis. Rotation about the common axis can be braked or locked. The chair can be lowered downstairs with a person pulling on the upper handle 84 and another person pushing on the lower handles 82 in order to slow movement of the chair down the stairs.

Abstract: A stair chair is provided and includes a seat 30, a backrest 34, a foot rest 32, upper handles 84 and lower handles 82. Three wheels 62 are mounted at each side of the chair. The wheels are pivotal about their own axis and also a common axis. Rotation about the common axis can be braked or locked. The chair can be lowered downstairs with a person pulling on the upper handle 84 and another person pushing on the lower handles 82 in order to slow movement of the chair down the stairs.

Abstract: A trolley 10 can be moved between a raised position and a lowered position. The trolley is usually in the lowered position when it is put into an ambulance. A magnet 252 is secured to one connecting leg of the trolley and a counter 258 is connected to the top frame 16 of the trolley. When the trolley is moved to a lower position the magnet 252 comes in close proximity to the counter 258 and a count is recorded. The recorded count gives an indication of the number of times that the trolley has been raised and lowered.

Abstract: In a synthetic aperture radar system, information concerning the radar reflectivity of a point on the ground is placed in an image at an azimuthal (cross-range) position which corresponds to the position of zero Doppler frequency shift of the received signal, under the assumption that the antenna has followed a straight line trajectory. In practice, the antenna trajectory will undergo small deviations about this straight line path which are not taken into account in the azimuth processing and which, consequently, cause incorrect azimuthal positioning in the image of the information concerning a point target on the ground.The invention uses the value of the slope of the frequency modulation of the received signal, calculated by means of an autofocus procedure, to determine the intercept of this frequency modulation at successive azimuth positions.