Abstract: A noninvasive pulsed fluorescence gas velocimeter that determines dynamic parameters of a gas flow from detection of fluorescent re-radiation of excited molecules of the gas. The present invention has higher altitude capability than devices that utilize particulate scattering. The velocimeter requires no probes and utilizes a laser or other light source that does not perturb the gas flow being measured.

Abstract: Laser Doppler anemometer with a wavelength-stabilized laser diode (1) whose beam after splitting (7) is so concentrated in a definite area (9) of a particle-containing flow of a fluid with the velocity (17) that in this area (9) an interference fringe pattern is produced, and with at least one semiconductor photodiode (13) on which the laser beams (10, 11) progressing from the area (9) are refocussed after elimination of scattered light fractions by a scattered light trap (diaphragm stop) (14), for the detection of the difference signal I between incident light intensity I.sub.o and scattered light intensity I.sub.scatter which the particles contained in the fluid emit into the whole solid angle 4.pi., where I=I.sub.o -I.sub.scatter. By detection of the laser beam of the intensity I which is modulated with the Doppler frequency after having passed through the point of measurement (9), the whole light intensity I.sub.scatter emitted by the particle into the solid angle 4.pi.

Abstract: A secure satellite over-the-air rekeying method and system are shown. This system provides a geometric filter for allowing message input to a satellite from ground stations having a particular predefined geographic location. Messages transmitted from an allowable ground site having a proper location are received and processed. Messages from improper geographic ground stations are discarded by the system. The messages include over-the-air rekeying information. The secure satellite over-the-air rekeying method includes ground station transmissions to the satellite to be rekeyed. The satellite receives these transmissions from the ground station system. The satellite determines whether the geometric position of the ground station corresponds to a predetermined allowable position. If the position is an allowable one, the satellite system processes the received information and rekeys the satellite.

Abstract: A method and device for inexpensively and efficiently controlling the distribution of pay-per-access information services is disclosed including varying scrambling methods and user exchangeable cards.

Abstract: In order to selectively jam M selected channels to selected subscribers in a CATV system, each of M different oscillating signals, each of which oscillating signals has a duration longer than the duration of the horizontal synchronization signal of the television channel it is to jam and a frequency higher than the carrier wave of the channel it is to jam, are in turn added to the television signal circuits of those subscribers who are not authorized to receive the particular channel being jammed by the jamming signal being added. The television set of the non-authorized subscriber picks up the higher frequency jamming signal as the valid horizontal synchronization signal and therefore ignores the valid horizontal synchronization signal, with the result that the channel in question is unviewable on the television set of the non-authorized subscriber.

Abstract: Apparatus and method for sonar or radar target tracking. Digital apparatus nd techniques are employed. A variable delay is used for beam steering.

Abstract: A time of flight velocimeter wherein a radiation source projects two parallel beams into an air mass. Each of the parallel beams converges into a waist portion. As an aerosol particle moves through the waist portion, part of the radiation of each of the beams is backscattered. This backscattered radiation is focused onto two detectors, one for each beam. Signals from the detectors, generated in response to the backscattered radiation, are processed to determine the velocity of the particle which has passed through the waist portion of the two beams.

Abstract: Apparatus operable in accordance with the method of the present invention for measuring the angle of incidence of a light beam or plane relative to level comprises a photodetector array for sensing the light and a level mirror preferably comprising a pool of mercury. Optics are provided for transmitting the light to the photodetector array in alignment with the angle of incidence of the light (aligned light) and also after the light has been reflected from the mercury pool (reflected light). A shutter is provided for separating aligned light from reflected light such that distinct signals representative of the two are generated by the photodetector array. The distinct signals are processed by up-counting and down-counting a counter circuit to determine the average centers of light spots representative of the aligned light and the reflected light and the distance between those average centers which is representative of the deviation of the light beam or plane from level.

Abstract: A system of double-pulse particle velocimetry, according to which small scattering particles are illuminated by two short pulses of laser light and then images are recorded photographically to produce a record from which the particle velocity can be determined by measuring the displacement of the particle images. Particle images is understood to mean both the non-overlapping individual particles and overlapping, coherently interfering images commonly referred to as "speckle". In order to resolve the directional ambiguity inherent in the system, artificial shifting is effected in the image field between exposures by an amount that is greater than any negative displacement occurring in the field, such shifting being performed here by means of an electro-optical device in place of the shifting previously produced by rotating mirrors and the like.

Abstract: An electrooptical sensor system directly measures the angle between two nearly parallel collimated laser beams. After focussing with a positive lens, the beams pass through a photoelastic modulator, a quarter wave retardation plate, and two polarizers. The beams then hit a lateral cell position sensor. Electrical signals from the lateral cell are processed with special electronics to yield a voltage which is proportional to the angular difference between the two beams. The sensor measures extremely small angles and operates at a high bandwidth. Its primary application is in the control of phased array optical telescopes.

Abstract: A chemical protective hood is made of nylon/butyl cloth and assembled using t butt and tape method of construction with the joints thereof covered by nylon/butyl tape. The hood has a cap portion with a face piece opening in which is mounted a butyl/natural rubber face piece in sealed relationship with the cap portion. The face piece includes eye lens ports, a voicemitter port and a canister port to accommodate projecting portions of an underlying gas mask. The face plate is elastic and elastically seals with the projecting portions of the face mask. The collar portion extends down from the cap portion and includes an elastic band for slightly constricting the neck portion while a cape portion projects down from the neck portion and includes a pair of underarm straps having elastic portions for holding the cape portion in place. VELCRO piles are attached to the collar portion and cape portion for securing the cape portion up when it is desired to provide some ventilation under the hood.

Abstract: Improved passive and laser-conditioned magnetic field sensor of compact and integrated construction for enabling the detection of a magnetic field as well as an improved method of manufacture for assembling and selectively pretensioning a subassembly in order to provide an enhanced formation of the subassembly prior to use. The sensor is generally made up of a magnetic field sensing device, first and second fiber-optic elements, first and second couplers, a laser source and a combined detector and analysis means. The first and second couplers interconnect the first and second fiber-optic elements. The magnetic field sensing device is advantageously connected to one of the fiber-optic elements and is generally made up of a magneto-strictive material (MSM) of ribbon-like shape, a nonmagnetic substrate and a sensing element of optic fiber construction. This element is of predetermined and selective multistrand design between its ends and of generally serpentine shape.

Abstract: A high average power pockels cell is disclosed which reduces the effect of thermally induced strains in high average power laser technology. The pockels cell includes an elongated, substantially rectangular crystalline structure formed from a KDP-type material to eliminate shear strains. The X- and Y-axes are oriented substantially perpendicular to the edges of the crystal cross-section and to the C-axis direction of propagation to eliminate shear strains.

Abstract: A crossover for microwave electromagnetic radiation is constructed in a planar configuration for the transference of all of the power of a wave in a first transmission line to a wave in a second transmission line. The crossover is formed of two pairs of cross arms wherein, in each pair, the arms are spaced apart by an electrical length of ninety degrees along the first and the second transmission lines, and couple power of the waves between the first and second transmission lines with an introduction of a quarature phase relationship. The impedance presented to a wave of a cross arm is less than the corresponding impedance of the first and the second transmission lines by a factor of the square root of two to inhibit the generation of relections at junctions between a cross arm and the first or the second transmission line. Each junction provides for a diversion of one-half the power of the wave from the first or the second transmission line to a cross arm.

Abstract: A method and apparatus for increasing the angular aperture of an acousto-optic device employing an acoustic zone plate positioned on an acoustic input face of an acousto-optic device. The angular spread of acoustic energy within the acousto-optic device is increased over the angular spread obtainable with a single transducer of the same length; thus providing an increased angular aperture for the resultant acousto-optic device.

Abstract: Disclosed is a bearing device for crankshaft wherein the cross sectional configuration of a ball-rolling groove of the inner race is so formed as to permit the ball-rolling groove to have a radius of curvature greater than the radius of the rolling ball, thereby to provide a clearance between the rolling ball and the ball-rolling groove permitting the rolling ball to be moved from one side to the other side of a central vertical line of the ball received by the outer race.

Abstract: An automatic switching circuit controls operation of a light. The circuit includes a voice recognizer and a manual switch. The switching circuit turns the illuminator on instantly in response to an "ON" command input via the manual switch or via the voice recognizer. The switching circuit turns the illuminator off a predetermined period of time after detecting an "OFF" command input via said manual switch or via the voice recognizer.

Abstract: A box-like container having a bottom support and a tubular body features a slide gate on the tubular body to facilitate the selective removal of bulk pack materials such as metal powders and the like.

Abstract: Magnetic support structure for a rotatable machinery part is described which comprises a stationary support structure, an annular stator comprising an array of a plurality of electromagnets or one or more electrically conductive or superconductive elements supported by the support structure about an axis, rim structure attached to the periphery of the rotatable part for rotation therewith about the axis radially inwardly of and proximate to the electromagnets, the rim structure including electrically conductive non-ferromagnetic material for magnetic interaction with the stator, and a source of power for selectively energizing the stator.

Abstract: An improved method and system for a depleted uranium calorimeter detector used in high energy physics experiments. In a depleted uranium calorimeter detector, the energy of a particle entering the calorimeter detector is determined and the output response of the calorimeter detector is compensated so that the ratio of the integrated response of the calorimeter detector from a lepton to the integrated response of the calorimeter detector from a hadron of the same energy as the lepton is approximately equal to 1. In the present invention, the energy of a particle entering the calorimeter detector is determined as a function of time and the hadron content of the response of the calorimeter detector is inferred based upon the time structure of the energy pulse measured by the calorimeter detector. The energy measurement can be corrected based on the inference of the hadron content whereby the resolution of the calorimeter can be improved.