Abstract: The present invention provides a fiber optic coupling apparatus for coupling light from a high power light source into a fiber optic while preventing thermal damage to the fiber optic at the fiber-to-light source coupling. The light source comprises a housing having a fiber input structure with inner surfaces defining a through-hole for receiving the fiber optic. The fiber input structure has outer surfaces which define a substantially conical profile of the structure that extends within the housing such that an axis of symmetry of the fiber input structure is substantially coincident with the light input to the fiber optic. The fiber input structure is further made from a high heat conductivity material and has a reflective coating on an input end face for reflecting light that is outside the acceptance angle of the fiber optic, but incident upon the fiber input structure.

Abstract: The present invention provides a fiber optic connector having a shielding apparatus for protecting the exposed end of a fiber optic. The shielding apparatus of the connector generally comprises a cylindrical housing, a collet, and a protective sleeve. The cylindrical housing comprises first and second ends and a through-hole for reception of a fiber optic having a fiber optic end protruding from the first end of the cylindrical housing. The collet comprises a tubular body with first and second ends and a through-hole passing between the ends for movable reception of the cylindrical housing, with the second end of the tubular body being split to form a plurality of prongs arranged coaxially with the through-hole of the collet.

Abstract: An electromagnetic radiation source, such as an arc lamp, is located at a point displaced from the optical axis of a concave toroidal reflecting surface. The concave primary reflector focuses the radiation from the source at an off-axis image point that is displaced from the optical axis. The use of a toroidal reflecting surface enhances the collection efficiency into a small target, such as an optical fiber, relative to a spherical reflecting surface by substantially reducing aberrations caused by the off-axis geometry. A second concave reflector is placed opposite to the first reflector to enhance further the total flux collected by a small target.

Abstract: The present invention provides a compact surgical headlamp capable of dynamic adjustment of the resulting field of illumination, comprising at least a single core fiber optic delivery light guide, an adjustable light projection system, and a mounting mechanism for movably supporting the headlamp proximate to the surgeon's eyes. A receiving block is also provided for supporting the structure of the projection system and for coupling the delivery fiber thereto. The projection system comprises a cylindrical housing mount adapted with a centrally disposed cylindrical cavity for receiving the ferruled, output end of the delivery fiber and for allowing the light output therefrom to initially diverge within the cavity of the housing mount.

Abstract: HOBr solution for biocidal treatment is produced by electrolysis of mixed chloride/bromide solution. The chloride: bromide molar ratio is greater than 4:1. The molar ratio and rate and period of electrolysis can be selected so as to result in high yield of HOBr, preferably over 90% of theory, and little or no residual HOCl. The process can suitably be carried out by recirculating the mixed halide electrolyte through an electrolytic cell for a time appropriate to achieve the desired result, and then discharging the solution to a receiving system.

Abstract: An off-axis optical system for collecting and condensing electromagnetic radiation utilizes an ellipsoidal reflector or a portion thereof configured so that the effects of magnification and optical aberrations (caused by the off-axis arrangement and an aspherical source envelope) are minimized. This is accomplished by the utilization of a specially designed ellipsoidal reflector having primary and secondary focal points along the major axis of the reflector or an effective reflecting portion thereof defined as that portion which is both illuminated by the source and subtended by the acceptance cone of the target.

Abstract: An analyzer for detecting explosives has at least one source and a plurality of gamma ray detectors. An article to be analyzed is moved adjacent the source and detectors and is subjected to neutrons which generate gamma rays in any nitrogen in the article. The gamma rays are detected and analyzed to determine the nitrogen concentration within the article. In order to achieve an area of uniform detection there are a plurality of detectors equidistant both from each source and from the article to be analyzed. In order to avoid a decrease in sensitivity away from the sources and detectors, there may be a second opposing array of sources and detectors on the opposite side of the articles. For greatest uniformity of detection, a source in one array opposes a detector in the other array and vice versa. Transmission of radiation from the analyzer is kept at safe levels by enclosing the analyzer within shielding which includes shield members extending from a trolley or other transport mechanisms.

Abstract: An apparatus for investigating a sample with ultrasound has a probe head formed by a casing, a transducer element of piezoelectric plastics material, and a source for applying a high frequency pulse to the sample. The source is preferably one end of an optical fibre, which fibre extends to a laser remote from the probe head. The transducer element is connected to the sample by an acoustic coupling medium, e.g. water. Thus, the probe head can be moved relative to the sample, and a compact, but efficient, structure is achieved.

Abstract: A hollow glass waveguide such as an optical fibre comprises a glass cladding containing in excess of 90 mole % germanium dioxide, the balance of the cladding being made up of modifying oxides such as network modifiers and intermediate modifiers. The use of high concentrations of germanium dioxide results in the waveguide having good optical properties in the 9-11 .mu.m wavelength range e.g. low transmission losses. The incorporation of small quantities of modifying oxides produces improved physical properties e.g. better fibre drawing capability and reduced tendency to devitrification. A particularly preferred cladding contains 94 mole % GeO.sub.2, 3 mole % Na.sub.2 O and 3 mole % Al.sub.2 O.sub.3.

Abstract: A cord, thread or filament is treated by applying to it a dilute solution of a polysiloxane prepolymer which is then cured, such that either (a) the outer envelope of the cord, thread or filament is enrobed, or (b) in the case of a cord or thread, the filaments thereof are substantially individually encapsulated by, a coating of cured polysiloxane polymer. The treated cords, threads and filaments have inter alia improved abrasion and fray resistance, water repellance and slip qualities.

Abstract: A piezoelectric transducer of piezoelectric plastic material comprises a body and activated transducer film formed integrally. Electrodes are formed on opposite sides of the film, and a backing material supports the film on one side. The transducer may be formed by molding, applying the electrodes and activating the film by means of a corona discharge.

Abstract: The ends of bristles of a brush, e.g. a toothbrush, are treated with a polysiloxane prepolymer which is then cured. The treated bristles are smooth and round-ended.

Abstract: An improved spatial filtering system includes a plurality of tracker modules for isolating selected signals from an array of signal data values collected from a signal environment by a plurality of receiver elements and stored in a residual signal storage element. Each tracker module includes a generating module for generating, from the array of signal data values, estimated contributions of a selected signal at each of the plurality of receiver elements. Each tracker module also includes an output signal estimation module, connected to the generating module, for determining, based on the estimated contributions, an output signal that is representative of the selected signal.

Abstract: A gas sensor has a layer of a semiconductor organic polymer, such as polypyrrole which is exposed to a gas to be detected. An alternating electric signal of varying frequency is applied to the sensor by an analyser, which detects the change in impedance characteristics of the sensor. The characteristics obtained are compared by microcomputer with reference characterisitcs stored in a memory. The resulting difference spectra depend on the gas in contact with the sensor and so the gas can be detected.

Abstract: A prepolymer composition for forming a scratch-resistant coating, comprising an acidic, aqueous solution of a polysiloxane prepolymer having non-coreactive side groups and co-reactive side groups other than hydrolysable groups, the composition being curable by evaporation of solvent and a decrease in acidity causing the co-reactive groups to react together to cross-link the polymer. Suitable co-reactive side groups are amino, epoxy and thiol. Suitable non-coreactive side groups are alkyl and gamma methacryloxy propyl. Acidity is suitably achieved by using a volatilisable organic acid such as acetic acid, so that it evaporates with the solvents to decrease the acidity.

Abstract: An analysis method and system for analyzing coal or other material causes the material to be bombarded with neutrons from a source, and this generates gamma rays from the material which are detected by a detector. The detector has scintillators which generate light when a gamma ray is detected, the light being detected by photomultipliers. Each gamma ray generates two other gamma rays, which may both be wholly absorbed in one or the other scintillator, or one absorbed in one scintillator and one in the other. By analyzing these events, the spectrum of gamma rays may be obtained, giving the composition of the material. One preferred detector has an array of scintillators and coincident gamma ray detection events in three adjacent scintillators detected by detecting if a primary scintillator detector event is coincident with detection events in the other two scintillators.

Abstract: A conversion apparatus for quantizing an initial set of weights for a weighted sum signal processing system having one or more conversion arrays. Each conversion array stores a plurality of values to be converted, quantizes the values that are to be converted to produce a set of discrete values and a set of error values, and replaces the stored values with the set of discrete values. Each conversion array combines the set of error values with a set of transformation weights to form one or more transformed error sets. The conversion apparatus further includes a transfer device for successively combining the one or more transformed error sets most recently formed with the contents of a successive conversion array. The transfer device monitors the successively produced sets of error values and halts the successive conversions and combinations when a predetermined condition is satisifed. The invention also features methods of quantizing initial sets of weight.

Abstract: A high-speed, limited-shift signal processor for quantized weighting of an input signal, which receives the input signal and delays is to provide a plurality of delay outputs and selects a number of the delay outputs to be modified by limited shifting of their place values. The limited-shift signal processor generates at least one weighted value from each delay output, including shifting the digit positions of each selected delay output to shift its place value, and sums each of the place-value-shifted delay outputs to obtain a weighted sum signal of the input signal.

Abstract: A conversion apparatus for quantizing a set of weights for a weighted sum signal processing system, including a predetermined number of conversion arrays operable in succession and a transfer and monitor circuit. Each conversion array stores a plurality of values to be converted, quantizes the values to be converted to produce a set of discrete values and a set of error values and replaces the contents of the means for storing with the set of discrete values. Each conversion array also combines the set of error values with a set of interpolator weights to form a transformed error set. The transfer and monitor circuit successively combines the transformed error set most recently formed with the contents of a successive conversion array, monitors the successively produced sets of error values, and halts the successive conversions and combinations when a predetermined condition is satisfied. The invention also features a method of quantizing such a set of weights.

Abstract: A hollow optical fibre waveguide for low loss transmission at mid infra-red wavelengths, and particularly in the region of the CO.sub.2 laser wavelength of 10.6 microns, is made of a germanium dioxide based glass, preferably comprising not less than 80 wt. % GeO.sub.2 and not more than 20 wt. % PbO, and has at least the inner surface of the hollow glass fibre devitrified and/or provided with a thin germanium lining. This change at the inner surface of the hollow fibre reduces transmission loss at the wavelengths of interest, and is effected by heat treatment at a temperature of at least 400.degree. C., simultaneously with exposure of the inner surface to a reducing atmosphere if a thin germanium layer is required at the inner surface.