Abstract: A pesticidal or herbicidal composition in particulate form which comprises composite particles. Each of said particles contains a core of an inert substance having a pesticidal herbicide associated therewith and a coating of an electrically resistive material around the core. The particles may also include a second pesticidal material adhering to the electrically resistive coating. The particles carry an electrostatic charge.

Abstract: A method of preparing a porous metal comprises reducing a mixture comprising (I) a source of metal; (II) a solvent such as water; and (III) a structure-directing agent such as octaethylene glycol monododecyl ether to form a liquid crystalline phase in the mixture. The reduction of the mixture having a liquid crystalline phase, for example using zinc metal as reducing agent, provides a porous film having a substantially regular structure and substantially uniform pore size.

Abstract: A method of killing flying insects which method comprises spraying into the air in which insects are flying liquid droplets of an insecticidal composition, a unipolar charge being imparted to the said liquid droplets by double layer charging and charge separation during spraying, the unipolar charge being at a level such that the said droplets have a charge to mass ratio of at least +/−1×10−4 C/kg.

Abstract: Tin-doped photosensitive optical glass is disclosed, together with applications of the glass in fabricating waveguides and waveguide devices such as Bragg gratings.

Abstract: Multiple-cavity fiber optic lasers are fabricated with high-gain fibers in low-loss, high-finesse fiber ferrule resonance cavity configurations supported in low-loss ferrule alignment fixtures developed for use in FFP filters. These lasers incorporate rare-earth doped, sensitized glass fiber as the active medium within FFP cavities. FFP lasers of this invention include those exhibiting single-frequency and/or single-polarization mode operation with wide mode separation. Lasers provided include those with short cavity lengths, where the longest of the cavities of can be less than or equal to about 10 mm in length. These FFP laser sources are fixed-frequency or discretely-tunable. Multiple-cavity configurations in which at least one of the cavities formed contains active fiber are readily formed in fiber ferrule assemblies. FFP lasers can be end-pumped using single- or double-pass pumping configuration or pump resonance cavity configurations.

Abstract: A method of generating an adsorbent product for use in magnetic separation of contaminants from an influent liquid comprises the steps of: (i) mixing at least one micro-organism with the liquid in a chemostat vessel; (ii) magnetically separating a magnetic fraction of liquid from the vessel from a non-magnetic fraction (iii) returning the magnetic fraction to the vessel; and (iv) collecting precipitated material from the vessel for use as the adsorbent product. In an embodiment, a solution comprising heavy metals is fed to a chemostat containing sulphur-generating micro-organisms, iron, sulphates and a nutrient compound together with N.sub.2. Liquid is drawn off to a high gradient magnetic separator where the non-magnetic fraction containing decontaminated liquid is separated off; the slurry is removed for use as an adsorbent. Sulphide generating micro-organisms are listed. Dy and Er salts or complexes can be added, as can other specified micro-organisms.

Abstract: A method for high grade magnetic separation using a matrix having one or more magnetizable matrix elements, wherein each element comprises a pair of poles aligned substantially parallel to a direction of flow of a slurry fluid containing particles to be separated, whereby a rear fluid vortex attributable to the upstream pole extends substantially to meet a front fluid vortex attributable to the downstream pole.

Abstract: Pest control wherein at least part of a pest is exposed to particles which carry an electrostatic charge, preferably of opposite polarity to that of the surface of the pest, and which may be sticky or tacky and comprise a wax, for example, a plant wax, such as, Carnauba wax, or an inorganic material, such as, talc. A pesticide, such as, a chemical or microbial insecticide, or a behavior modifying chemical may be associated with the particles which may also be dispensed in and/or dispersed via a liquid or gaseous carrier, possibly from a pressurized gas or aerosol dispenser at whose nozzle the particles are charged electrostatically by friction. In a preferred embodiment, a trap with a lure (45, 53) has a surface (34), preferably sloping, coated with the particles for destabilizing pests and a trapping zone (41, 43) into which destabilized pests fall from the particle-coated surface (34) and are retained for subsequent disposal.

Abstract: An insect trap device comprising a housing, the housing having an interior which is in communication with the atmosphere outside the device, the housing containing:(i) an insect attractant source;(ii) means for generating an ion wind to facilitate dispersal of the insect attractant source into the atmosphere outside the housing; and(iii) insect retaining means.

Abstract: Passive, self-adjusting and tracking optical wavelength filters are described. The filters are absorptive and can be of either transmissive or reflective type. The filters comprise an unpumped doped optical waveguide configured so that signals of different wavelength are spatially decoupled to some extent. The self-adjustment of the filter centre wavelength is achieved by the combined effects of the power-dependent saturable absorption, provided by an appropriate dopant, and partial longitudinal hole burning provided by the spatial decoupling of the different wavelengths. External cavity lasers using this type of filter in the external cavity are also described. This external cavity configuration can provide stable single frequency operation of, for example, a semiconductor laser. By using a saturable absorber for the external cavity (e.g. an erbium doped fibre), longitudinal mode-hopping can be suppressed, ensuring single frequency operation.

Abstract: An optical device comprises an optical fiber directional coupler having at least a first optical fiber optionally coupled at a coupling region to a second optical fiber such that light can propagate in the coupling region in at least two possible electromagnetic transmission modes; and means for transferring energy between the modes by a spatially periodic perturbation of at least a part of coupling region.

Abstract: A method of attracting insects selected from the group consisting of houseflies, mosquitoes and wasps to a particular location, which method comprises placing at the said location a lure containing an effective attractant composition which comprises at least one compound which is a substituted benzenederivative having one or more short side chains, the said compound being volatile at room temperature and having a molecular weight in the range of from 115 to 155.

Abstract: An optical fiber has a cladding glass layer surrounding a glass core, in which a region (preferably annular) of the optical fiber partially overlapping the cladding and/or the core is formed of photosensitive glass.

Abstract: A beam shaping device for a laser device is provided. The laser device has a beam with a first beam quality factor M.sub.x.sup.2 in a first direction, and a second beam quality factor M.sub.y.sup.2 in an orthogonal direction. The beam shaping device includes at least one reflecting surface diverting at least a first part of the beam in order to reconfigure at least one of the first and second beam qualities M.sub.x.sup.2 and M.sub.y.sup.2.

Abstract: A process for the preparation of electrostatically charged particles of a high resistivity material which process comprises incorporating a unipolar charge into the material at a temperature at or above the glass transition temperature thereof or above the melting point thereof, the said unipolar charge being incorporated into the bulk of the material and the charged material being subsequently comminuted, or the said charge being incorporated into the material while forming particles thereof.

Abstract: An optical fibre distributed feedback laser comprises an amplifying optical fibre (50) operable to provide optical gain at a lasing wavelength, in which a diffraction grating (30) is disposed on at least a portion of the amplifying optical fibre to provide distributed optical feedback for sustaining lasing action at the lasing wavelength.

Abstract: An optical amplifier for amplifying signals of different wavelengths throughout a spectral window modifies the amplification of each signal such that the output levels of the signals are more equal than the input levels thereof when the input levels differ by more than a predetermined amount. In one embodiment this is achieved by providing a dichroic reflector at one end of an amplifying fibre so that standing wave patterns are set up in the amplifying fibre by interference of the forward and reflected signal lights, at the different wavelengths, the signal at each wavelength preferentially decreasing its own gain with increasing signal level.

Abstract: Two beams of laser light are directed onto the surface of a rotary shaft at points (12a, 12b) spaced longitudinally along the shaft from one another. Light backscattered by the optically rough surface of the shaft is detected by means of detectors (18a, 18b) which produce output signals related to the detected intensity. Signal-processing means (20a, 20b) associated with each beam include memory means for storing a reference waveform. The signal-processing means (20a, 20b) provide a signal indicative of the phase of the detected intensity relative to a reference waveform stored in the memory means. A comparator (22) compares the output signals from the signal-processing means (20a, 20b) to provide an indication of torque transmitted through the shaft (12). Alternatively, a single beam and detector may be used to give an indication of angular position of the shaft.

Abstract: A device for separating magnetic materials from non-magnetic materials in a sample using an applied magnetic field includes an inverted upstream funnel containing a plurality of longitudinally spaced, non-magnetisable flow-smoothing surfaces extending transversely across the width of the funnel, a coaxial filter chamber coupled to the output end of the upstream funnel having mounted therein an ordered wire array of magnetisable wires and a coaxial downstream funnel containing a plurality of longitudinally spaced, non-magnetisable flow-smoothing surfaces extending transversely across the width of the downstream funnel. The device may be used to separate magnetically labelled materials from samples such as biological samples.

Abstract: Compact, fixed-wavelength and tunable fiber optic lasers combine a sub-millimeter length of high-gain rare-earth-doped, sensitized glass fiber within a fiber Fabry-Perot (FFP) cavity. Tunable, single-frequency fiber lasers at 1535 nm employing high-gain erbium:ytterbium phosphate glass fiber are specifically provided. Single-frequency and/or single-polarization mode erbium:ytterbium glass fiber lasers, having cavity lengths less than about 200 .mu.m with continuous wavelength tuning range over several nanometers are provided. Amplified single-frequency lasers incorporating fiber rare-earth ion optical amplifiers are also provided. Single-frequency lasing employing sub-millimeter lengths of rare-earth doped sensitized fiber in a 3 mirror laser design is also demonstrated.