Abstract: The present invention discloses a process for determining which material within a vicinity of an electrically conducting material is causing corrosion of the electrically conducting material. The process includes providing a piece of electrically conducting material, a piece of potentially corrosive material that is present in the vicinity of the electrically conducting material, an electrical resistance measuring device and a testing chamber. Thereafter, the piece of electrically conducting material and the piece of potentially corrosive material are placed within the testing chamber and the electrical resisting measuring device monitors the electrical resistance of the piece of electrically conducting material as a function of time.

Abstract: The present invention discloses a process for determining which material within a vicinity of an electrically conducting material is causing corrosion of the electrically conducting material. The process includes providing a piece of electrically conducting material, a piece of potentially corrosive material that is present in the vicinity of the electrically conducting material, an electrical resistance measuring device and a testing chamber. Thereafter, the piece of electrically conducting material and the piece of potentially corrosive material are placed within the testing chamber and the electrical resisting measuring device monitors the electrical resistance of the piece of electrically conducting material as a function of time.

Abstract: A thermal imager system comprises a scanning system 1 for scanning a required scene 2 and an anamorphic optical system 3 for focusing the scanned scene onto a Sprite detector 4, the optical anamorphic system comprises a pair of optical prisms 17, 19 disposed between a collimating element 15 and a focusing element 21, one or both of the prisms 17, 19 being pivotally mounted whereby the anamorphic ratio and hence the focal length of said optical system 3 may be changed. (FIG. 1).

Abstract: A scanning thermal imager includes means to compensate for a degree of undesirable asymmetry introduced by an element such as a spherical lens operating in an off axis manner. The means can advantageously include an optical element mounted in the optical path with at least one main face at an angle other than normal to the path and arranged to introduce a desired degree of compensating asymmetry.

Abstract: A thermal imager employs an intermediate field stop (8) which is preferably placed at an intermediate image plane (P) in front of a cryogenically cooled detector (1) mounted on a substrate (2). Radiation gathered by a telescope is directed onto the detector through an aperture (9) in the field stop. The field stop limits the rays which are emitted by the detector and substrate and which are subsequently retro-reflected back to the detector (called narcissus rays).

Abstract: Catadioptric optical systems are generally arranged to view a fixed large field of view. Apparatus for steering a field of view includes a pair of Risley prisms, which are disc shaped prisms having a generally shallow wedge like side cross-section, arranged in the path of the incoming radiation. The prisms are rotatable with respect to each other and to the optical axis of the system so as to steer the field of view.By utilizing such steering in a dual waveband system then a system having two fields of view and two magnifications may be achieved in which an image over a smaller field of view but of high magnification may be steered within a larger image of large field of view but low magnification.

Abstract: A thermal imager including a cryogenically cooled detector element array and a scanning element has an optical system with a field of view limited by a field stop (2). A retroreflective region (6) is provided on part of the field stop to act as a temperature reference by allowing the detector array to "look at" itself. A second, different temperature reference (5) is provided on another part of the field stop and the two references are used to equalize and adjust the output characteristics of the elements in the detector array.

Abstract: An artificial bait of the type of a hollow, transparent body having a front, blunt portion, wherein the front or head portion of the bait is of a color distinct from that of the rest of the bait. The main body color of the bait is provided by a sheet-like insert in the body extending from the rear end to a point spaced from the end wall of the head portion. The front end wall is preferably concave and is provided with a paint layer, preferably applied to the exterior. Since both the front wall and the rest of the body is moulded from a transparent plastics material, the color of the paint applied to the front wall is also displayed at the side wall of the body. Accordingly, the color of the front portion, preferably red, is visible not only in front view but also at virtually any angle of viewing of the bait, except the exact rear view.

Abstract: A flasher of the type of an elongated, double-bent plate-like member is produced from two generally identical transparent plastic plates having reinforcements at their edges and interlocking each other to enhance dimensional stability of bends at the front and rear ends. Sandwiched between the plates is a light reflexive sheet which is fully protected from water when the flasher is completed.