Abstract: The apparatus provides a method of observing a water sample that is caused to flow rapidly past a beam of light of rectangular cross section. Attenuation of the beam by the sample is measured in a first detector that generates an output signal that has a basic, relatively slowly changing (e.g. half a second) component representative of the overall turbidity of the sample, and a series of short (e.g. 6 millisecond) pulses caused by individual, larger particles in the sample. The basic component is fed to a feedback circuit which so controls the light source as to maintain such component substantially constant. The intensity of the light source then provides a measure of the turbidity. A second detector counts the number of pulses above a certain threshold magnitude. In addition, this second detector can momentarily (during the occurrence of such a pulse) open a switch to prevent the feedback circuit from receiving the output signal of the first detector and hence avoid its reacting to the pulse.

Abstract: A converter for converting a series of digital input bits to an analog output employs a direct current comparator having a magnetic core and primary and secondary ratio windings coupled with the core. The primary winding is divided into two sections. A first group of the more significant input bits varies the number of turns of the first primary section which is traversed by a first direct current. A second group of less significant input bits varies the number of turns of the second primary section traversed by a second direct current. A direct current is also passed through the secondary winding, this secondary current being varied proportionally with the number of turns of the first primary section traversed by the first primary current. Modulation-detection windings arranged inside the core (which also acts as a magnetic shield) detect any net ampere-turns unbalance of the primary and secondary currents in the ratio windings.

Abstract: A flame deflecting device that comprises a fire resistant lamina and a protective casing mountable on a building exterior in rows above windows. Each device has a width greater than the window below. When mounted on a building, the device does not extend vertically by more than three feet (0.9 m). When activated on the occurrence of fire, the flame resistant lamina is released and extended substantially horizontally from the building exterior, thereby deflecting flames, smoke and hot gases escaping from below.

Abstract: The invention is concerned with a laser heterodyne interferometric method and system for measuring the displacement of a free surface of a material subjected to ultrasound. A laser beam having a predetermined intensity is generated and then divided into first and second beam portions having respective intensities representing minor and major fractions of the predetermined intensity, the first beam portion being angularly displaced relative to the second beam portion and being frequency shifted by a predetermined frequency. The second beam portion is passed through an optical lens off-center thereof to focalize the second beam portion onto the free surface of the material subjected to ultrasound, thereby scattering same. The scattered second beam portion is combined with the first beam portion to obtain an optical fringe signal which is converted into an electrical fringe signal comprising a central peak at the predetermined frequency and a sideband on either side of the central peak.

Abstract: The anemometer is for use in measuring two orthogonal velocity components of a fluid, such as air or water. When used to measure wind speed, the wind force acting on a sphere attached to a shaft tends to deflect the shaft from the neutral position. This deflection is measured by optical or electromagnetic sensors which control an electromagnetic actuator which generates a force opposing the wind force thereby returning the shaft to the neutral position. The actuator generates a force proportional to the square of the current applied to the actuator coils. Since the drag force is proportional to the fluid velocity squared (for one dimensional measurement), the wind speed measurement derived from the current applied to the electromagnet will be partly linearized. A microprocessoris used to compute the wind speed components or the wind speed and its direction from the electromagnet signals.

Abstract: A vehicle adapted for transporting and manipulating objects within a confined space, such as a tunnel. The vehicle comprises a pair of side frames interconnected by vertically adjustable front and rear interconnecting members that include horizontal portions onto which a boom is slideably and pivotally connected. Raising and lowering of one or two of the interconnecting members and lateral traversing of one or two of the connected boom portions provides for manipulation of an object or tool attached to the boom.

Abstract: A three dimensional imaging system operating in accordance with the known active triangulation method employs a laser beam that is projected onto an area of a surface the profile of which is to be examined. A beam reflected from such area is received in a position sensitive detector. With synchronised scanning of the projected and detected beams by a system of mirrors, the detected position in the detector remains unchanged when the surface under examination is a flat reference plane, changing only as a measure of the degree of deviation of each examined area from such reference plane in a direction Z. The system is characterised by this basic scanning being carried out in such a way that the beams are scanned in a direction X lying in the beam plane, i.e. the plane defined by the beams, and by a further simultaneous and synchronous scanning that takes place in a direction Y. The directions X, Y and Z are all mutually perpendicular.

Abstract: A differential thermal wattmeter of the type disclosed in U.S. Pat. No. 4,045,734 is modified to remove undesirable in-phase a.c. ripple at the fundamental frequency in the feedback path. This result is achieved by a closed loop system in which the in-phase signal in the feedback path is detected and driven to zero by injecting sufficient signal in opposite polarity into the feedback path to cancel the ripple. The advantages are reduction of error and the ability to use standard, low cost components.

Abstract: Hard to simulate, readily distinguishable from counterfeits, optical interference authenticating devices are provided by depositing two coatings on a substrate, each coating comprising at least one optical interference layer, the material of each layer being selected so that the two coatings together and separately have different spectral reflectance and spectral transmittance characteristics at different angles of incidence of light thereon. The substrate may be, for example, a polyester film and a first one of the coatings is sufficiently radiation absorbing of, say, infrared radiation that at least one portion of that coating can be removed by an infrared laser beam through, for example, a mask to provide a readily distinguishable pattern on the substrate.

Abstract: Two terminal negative admittance networks are disclosed. The preferred networks include a pair of opposite type transistors or a field-effect transistor combined with a bipolar transistor of the opposite type. These networks operate over a very wide frequency range and also can function with a very small operating current.

Abstract: The antenna feed includes a waveguide radiator with a conductive flange positioned about the waveguide near its radiating end. The flange includes one or more corrugations which each have tapered walls and which is truncated at its root and crest by a flat or curved plane. The corrugations thus may have a trapezoidal cross-section or a curved root and crest cross-section. The curvature may be sinusoidal.

Abstract: There is disclosed a new process for the conversion of the organic components of sludge, particularly sewage sludge, to produce useful, storable, energy-containing oil products, apparatus for carrying out the process and a control process for optimization of the process temperature. The sludge preferably is mechanically dewatered to about 20-25% solids by weight and thermally dried to about 90% solids by weight. The resultant material is comminuted and heated in the apparatus of the invention to at least 250.degree. C. in a heating zone in the absence of oxygen to generate a gaseous atmophere containing volatiles; this atmosphere is then removed, scrubbed of H.sub.2 S and NH.sub.3 if required, and passed preferably in countercurrent flow in a heated reaction zone in intimate contact with the "devolatilized" sludge solids from the heating zone, again in the absence of oxygen, at a temperature of at least 280.degree. C., resulting in catalyzed vapor phase oil-producing reactions.

Abstract: A heat exchanger for exchanging heat between incoming cold fresh air and outgoing warm exhaust air. The heat exchanger is constructed of a number of relatively long flexible plastic tubes supported within a flexible plastic outer housing. The inner tubes are supported in spaced-apart relationship within the outer housing. A manifold on each end of the tubes in sealing engagement with the inner tubes and with the housing so that air can be forced through the inner tubes in one direction and through the housing in the other direction. The diameters of the inner tubes and outer housing being large enough so that blockage by ice or frost is minimized.

Abstract: A direct reading detector/dosimeter for neutrons and other high LET radiation is described, comprising a selected, substantially transparent, elastic solid medium uniformly impregnated with droplets of an immiscible detector liquid. The detector liquid-in-solid is appropriately confined and rendered stable for storage by adding a layer of excess detector liquid and sealing in a container. On opening the container and removing the excess detector liquid, the detector liquid droplets become superheated and the detector/dosimeter is activated. Neutrons and other high LET radiation will trigger the vaporization of the superheated droplets and the selected elastic, solid medium will trap the products of vaporization and retain a visual record thereof over an extended time. The number of vaporization events can be counted to give a measure of the radiation dose.

Abstract: A plasma is induced in a transmissive medium, and causes a chirp to be impressed on an optical pulse. The chirped pulse when passed through a dispersing means is then compressed. Applications of this pulse compression technique include the generation of short pulses of infrared at high power levels. Picosecond pulses of 10 micron energy are generated by switching a 2 picosecond portion from the output of a multi-atmosphere laser oscillator, and amplifying the portion in a CO.sub.2 gain module operated at gain saturation to cause a plasma front to propagate with the portion being amplified. A blue chirp of the pulse results. The pulse is passed through a dispersive medium, and a substantial decrease in pulse width and increase in energy density occurs during successive passes of the pulse through the gain module. Pulses as short as 500 femtoseconds have been produced at power densities of the order of 10.sup.12 watts/cm.sup.2. A TE/CO.sub.

Abstract: Two new compounds which are attractive to male fall cankerworm moths, Alsophila pometaria, in the field, are described. They are (Z,Z,Z,E)-3,6,9,11-nonadecatetraene and (Z,Z,Z,Z)-3,6,9,11-nonadecatetraene. These compounds, separately and together, and these two compounds together with a third, [(Z,Z,Z)3,6,9-nonadecatriene], act as attractants to male fall cankerworm moths and can be used to monitor, confuse or attempt to control, populations of the moths.

Abstract: Apparatus for dispersing particulate material in a liquid, for example, particulate coal and agglomerating oil in water, comprising an upwardly extending, cylindrical container for the flow of the coal, oil and water upwardly therethrough passed a lower, flat blade type turbine rotor, an intermediate knife blade type turbine rotor and an upper pitched blade type turbine rotor. An annular shaped portion is around the intermediate rotor and houses the intermediate rotor in a cylindrical duct, longitudinally extending baffles extend upwardly along the container inner surface and are spaced therefrom. The lower rotor causes radially outward flow of the coal-water-oil mixture, the intermediate rotor causes fine break down and homogenization of the coal-water-oil mixture, while the pitched blade type turbine rotor causes reverse flow of the homogenized coal-water-oil mixture producing seed agglomerates of carbonaceous coal particles and oil leaving any ash particles dispersed in the water.

Abstract: Laser pulse generation techniques are disclosed in which two competing non-linear processes, e.g. stimulated Brillouin scattering and laser-induced breakdown are employed in combination to generate a short laser pulse. Narrow linewidth UV radiation amplified to the millijoule level in a XeCl discharge module has been used to generate pulses of less than 200 picoseconds in duration.

Abstract: Eddy current probes which are used to internally or externally inspect cylindrical components for localized defects have a main coil arrangement that induces and senses eddy current in the components. In accordance with the present invention, the probe further includes an element associated with the main coil arrangement to generate a detected defect signal distinct from a detected noise signal. The element can include one or more further coils mounted coaxially with the main coil arrangement so as to be between the main coil arrangement and the component to be inspected. The element may alternately be a cylindrical conductive sleeve mounted coaxially with the main coil arrangement so as to partially shield the coil arrangement from the component to be inspected. An electrical phase shifting network may be connected to the one or more further coils to enhance the distinction between the signals.

Abstract: A method which determines at least one property of a material by measuring the ultrasonic absorption in this material. In carrying out this method, the material is subjected to an ultrasonic wave having an intensity varying in time. Such a method can be performed by measuring a temperature modulation, produced by absorption of the ultrasonic wave in a probed region of the material, at a surface area corresponding to this probed region, by measuring the ultrasonic power over the probed region, and by calculating the ultrasonic absorption in this probed region from the measured surface temperature modulation and the measured ultrasonic power for the purpose of determining at least one property of the material. Of course, the calculated ultrasonic absorption is representative of this material property.