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: Polymeric monoliths having high stiffness and strength can be produced by heating an assembly of polymer fibres under a contact pressure to a temperature at which a proportion of the fibre is selectively melted and then compressing the assembly. Preferably at least 5% of the polymer is melted so that on compression the molten materials fills the voids within the assembly. The use of polyolefin fibres especially melt spun polyethylene fibres is preferred. The products are useful e.g. as orthodontic brackets, bone prostheses and in body armour.

Abstract: Polymeric monoliths having high stiffness and strength can be produced by heating an assembly of polymer fibres under a contact pressure to a temperature at which a proportion of the fibre is selectively melted and then compressing the assembly. Preferably at least 5% of the polymer is melted so that on compression the molten materials fills the voids within the assembly. The use of polyolefin fibres especially melt spun polyethylene fibres is preferred. The products are useful e.g. as orthodontic brackets, bone prostheses and in body armour.

Abstract: Process for the production of a homogenous polymeric monolith wherein an assembly of oriented thermoplastic polymer fibres is maintained under a contact pressure sufficient to ensure intimate contact at an elevated temperature high enough to melt a proportion of the polymer. The assembly is subsequently compressed at a compaction pressure higher than the contact pressure while still being maintained at the elevated temperature. The resulting polymeric products are useful, for example as orthodontic brackets, bone prostheses and in body armor.

Abstract: An apparatus to produce a low oxygen containing gas in which exhaust gases from an engine are cooled by passing them through a manifold cooler. Harmful gases are removed by passing the exhaust gases through a catalytic converter for removal of NOX. Air in injected and the exhaust gas passed through a further catalytic converter for removal of CO. The exhaust gases are then cooled by passing them through an air to gas heat exchanger, and a series of water-cooled heat exchangers which are water-cooled and the resulting condensate removed by condensate drain. The water coolant is supplied by a closed circuit radiator system. The exhaust gases are then passed through a condensate screen and two filter beds for removal of moisture which may be regenerated by passing warm air derived from the air to gas heat exchanger through them when not in use. The operation of the system may be regulated by a fuel management system which includes an oxygen sensor.