Abstract: To detect leaks from pipelines carrying fluids, especially oil, light is transmitted through a fibre-optic held in proximity with the pipeline. The fibre-optic is surrounded by a medium of which the refractive index is altered by the influence of the leaked fluid. In a preferred embodiment the medium is a silicone rubber (4) of which the refractive index is normally lower than that of a quartz fibre optic (3), but of which the index increases to that of the quartz or above when oil (7) soaks into it through a permeable cladding (1) and elastomeric protective layer (2), thus rendering the fibre optic non-internally--reflective so that light (6) is absorbed. Control means linked to a light receiver detect that change and the position of the leak is located to within the length of the optic. In another embodiment the medium is a liquid which is expelled from around the optic by the action of leaked fluid.

Abstract: Apparatus and method for testing unvulcanized rubber or rubber-like materials can work at high shear rates (e.g. 100 sec.sup.-1) as a result of applying and maintaining pressure on the test sample as it is being sheared by a rotor in a test chamber. The rotor is smooth-faced. Both conditions simulate more accurately the forces acting on such materials in such operations as extrusion.The test material is transferred into the test chamber through transfer ports from a transfer chamber by a pressure member which continues to exert pressure on material in the transfer chamber, which may be a next test sample.Specific operating steps of the rotor at varying speeds and directions to assess various useful parameters of the test material (including not only viscosity but also elasticity) are described, together with a mathematical model for rationalizing the behavior of the material under these test conditions.

Abstract: A fabric having an elastomer coat on each face of a woven layer and having resistance to water attack along the woven layer is formed by heating and stretching the yarn, the thread or the fabric of the woven layer, for example to achieve 20 to 30% elongation, so as to reduce or eliminate interfilamentary spaces and subsequently coating the woven layer. The fabric is of particular value for gas-cushion vehicles intended for travel over water.

Abstract: A safety wheel rim for use with pneumatic tires has a removable band which is securable so as to obstruct the mouth of the well used to receive the beads of a tire when fitting the tire onto the rim. The band can thus be locked against radial expansion regardless of the position of the tire beads so that the beads cannot accidentally enter the well in the event of deflation of the tire while travelling. The well may be offset from the median plane of the rim and also spaced from the bead-retaining flanges. Examples of the securing means for the band shown are an inflation valve stem which is screw-threaded through the outer of overlapping ends of the band and which cannot be inflated unless the band is secured, and screws arranged to tighten the band circumferentially.