Abstract: A process for the removal of impurities from a thermoplastic polymer, comprising mixing with the polymer in a molten state a stripping agent comprising a solution of carbon dioxide in water, passing the mixture to a vessel held at a pressure and which is less than atmospheric pressure, allowing impurities to defuse out of the polymer into the volatilised stripping agent, and removing the volatilised stripping agent with the impurities from the mixture. The invention also relates to the stripping agent itself, which is a solution of carbon dioxide in water.

Abstract: A coupling network for electromagnetic pulsed testing arrangements includes three stacks of toroidal ferrite cores. Two of the stacks are of identical diameter, the third stack has a diameter approximately equal to the combined diameters of the first two stacks. A copper tube looped through the central aperture of the first two stacks forms a primary winding. An insulated wire looped twice through the first two apertures forms a secondary winding of a 1:2 step-up transformer. The winding is extended through the aperture of the third stack. The third stack is operable to permit the laying in of a cable connected to a device under test. The cable forms the secondary of an isolation transformer.