Abstract: An apparatus for producing a collimating mark within an optical sighting device includes a light source to generate a beam of light for the mark, imaging optics, and a beam splitter. The beam splitter reflects one portion of the light from the light source into a sighting ray path and directs another portion of light on to a two-dimensional photosensor matrix. From the signals generated by the matrix, the actual position of the collimating mark is determined. A ballistics computer predetermines a set position. Control signals are generated based on an actual position/set position comparison to permit the continuous movement of the collimating mark such that it indicates the elevation and lead angles relative to the optical axis of the sighting device. The signals generated by the photosensor matrix are also used to control the contrast of the collimating mark with respect to its immediate surroundings.

Abstract: The part is subjected to action of an acid aqueous bath in order to cause the surface of the part to be porous over a thickness which is a fraction of the thickness of the zinc which it includes, and the part is caused to adsorb at least one sealing material.

Abstract: A toroidal or similar body (1) of a non-magnetic, insulating material, preferably glass fibre-reinforced plastic or ceramic is provided with at least three recesses for receiving in each case a corresponding one magnetoresistive sensor. The associated measuring directions of said sensors are orthogonal to one another. For producing a magnetic auxiliary field applied to the sensors, a coil is arranged on the body. for increasing the accuracy and reliability of the measured result, the body is provided with at least one further recess for receiving a further sensor. The measuring direction of the further sensor differs from that of other sensors and forms preferably the same angle with the other measuring directions. The body can be in multipart form and is in particular made from two identical parts.The apparatus can be used in electronic compasses and for north finding devices.

Abstract: Apparatus of all types for the separation of fluids which comprise at least one semi-permeable tubular membrane mounted on a porous support, the membrane being kept out of contact with adjacent parts of the apparatus by at least one thread-like element wound spirally around the membrane.

Abstract: Fluid fractionating membrane apparatus is described in which a jacket is provided with a fluid inlet and a fluid outlet for introducing and extracting a first fluid to and from the jacket, at least one core extending within said jacket. A number of continuous porous tubular membrane support elements, having at least one longitudinal channel connected to the exterior of the jacket, are wound uniformly either spirally or helically around the core and they are each provided with a membrane which covers the exterior surface thereof.

Abstract: A flexible semi-permeable tubular assembly is provided which consists essentially of a cord comprising a textile sheath which carries a semi-permeable membrane, said sheath being composed of yarns, the external surface of the sheath being compressed and flattened, the internal surface of the sheath defining an axial channel which communicates with the exterior. This assembly is particularly suitable for the concentration, separation and purification of fluids by reverse osmosis, ultra-filtration and gas permeation. The assembly combines good tensile strength with good porosity.

Abstract: Fluid fractionating apparatus comprising a jacket, two side plates forming with said jacket a closed chamber, at least one aperture formed in each side plate, a cap located at least partly in each aperture, each cap having a cavity communicating with the interior of the chamber and an orifice communicating via its aperture with the exterior of the chamber, a plurality of cylindrical elements extending substantially axially in said chamber and each comprising a textile sheath forming at least one channel, and a membrane covering the textile sheath and being joined thereto at each of its ends in a leakproof manner, the cylindrical elements having an external diameter of between 1 and 10 mm, the two ends of the cylindrical elements each being located in a fluidtight manner in the cavity of one of said caps, and means for feeding a fluid to and from the chamber. The cylindrical elements are grouped in bundles, the ends of the elements of a bundle being located in the cavity of a single cap.

Abstract: A selectively-permeable tubular element is provided which comprises an essentially tubular sheath of uniform textile material, the whole of which has been heated to a uniform temperature such that the sheath can subsequently be bent in an arc of radius of curvature not exceeding about 10 cm while retaining substantially circular cross-section, with a selectively permeable membrane applied to the sheath.