Abstract: A linear random block copolymer comprising segments of polyethylene oxide and a relatively more hydrophobic polymer, e.g. polypropylene oxide connected by hydrophobic segments containing urethane and urea groups formed from the reaction of a di-isocyanate and a diamine, wherein the diamine comprises less than 2% by weight of the total weight of the reactants used in the preparation of the copolymer.

Abstract: A linear random block copolymer comprising segments of polyethylene oxide and a relatively more hydrophobic polymer, e.g. polypropylene oxide connected by hydrophobic segments containing urethane and urea groups formed from the reaction of a di-isocyanate and a diamine, wherein the diamine comprises less than 2% by weight of the total weight of the reactants used in the preparation of the copolymer.

Abstract: Apparatus for cultivating plants comprises a vessel (15) for receiving a plant cultivating medium (10), the vessel wall having a number of apertures (30) which are substantially covered over by a water-permeable polymer (35) which controls introduction of aqueous media (25) into the vessel (15). The vessel (15) and polymer (35) sit in a reservoir (20) for the aqueous media (25). The polymer (35) may be water-swellable and may be a hydrogel and preferably is in the form of a film, membrane, layer or sheet having a thickness in the range 0.001 mm to 5.0 mm. The polymer (35) supports transport of the aqueous media (25) through the thickness of the polymer (35) by diffusion so that entry of aqueous media (25) into the vessel (15) by hydraulic or capillary flow is prevented. The diffusion rate is self-controlled by the plant species.

Abstract: A detection system for use in detecting the presence of a non-aqueous organic measurand is provided. The system comprises a fiber-optic probe assembly incorporating an optical fiber which is susceptible to micro bending anywhere along its length, and a body of material contained within a rigid containment structure, wherein said body comprises a material selected from the group consisting of a rubber, plastic and semi-crystalline/rubbery polymeric material which is subject to a volumetric change capable of inducing a microbend in said optical fiber in the presence of said non-aqueous organic measurand and wherein the body of material is a substantially continuous coating which has a thickness prior to contact with the non-aqueous measurand of less than 7.

Abstract: A detection system for use in detecting the presence of a non-aqueous organic measurand is provided. The system comprises a fibre-optic probe assembly incorporating an optical fibre which is susceptible to micro bending anywhere along its length, and a body of material contained within a rigid containment structure, wherein said body comprises a material selected from the group consisting of a rubber, plastic and semi-crystalline/rubbery polymeric material which is subject to a volumetric change capable of inducing a microbend in said optical fibre in the presence of said non-aqueous organic measurand and wherein the body of material is a substantially continuous coating which has a thickness prior to contact with the non-aqueous measurand of less than 7.

Abstract: A measurand is detected by a sensor element forming part of a transducer unit which is filled to an optical fiber or fiber capable such that the fiber is bent or curved to an abnormal level which introduces a measurable loss in the transmission characteristics of the fiber. The transducer unit has three spaced clamp members arranged to be clamped along the length of the fiber. The sensor element is fitted between clamp members and the fiber is guided over a bar located between clamp members.

Abstract: A system for detecting the presence of a target measurand, such as water or specified chemicals which are carried in an aqueous solution, and which includes a fibre-optic probe assembly which incorporates an optical fibre, a thin film of a water swellable hydrogel, and a rigid containment structure. The hydrogel is in contact with the optical fibre such that a volumetric change in the hydrogel causes a microbend of the optical fiber. The microbend is detected by a sensor assembly which is coupled to the probe assembly.