Abstract: A system for closely controlling the standoff distance of a nozzle in a remotely controlled fluid jet abrasive cutting system. The system comprises a head assembly having a support section and a nozzle body. Control means move the head assembly along a desired cutting path relative to the workpiece. A nozzle is mounted in the nozzle body and oriented to dispense cutting fluid along an axis directed against the workpiece. The nozzle body and the support section are interconnected by means which function to bias the nozzle body relative to the mounting section in a direction along the cutting axis of the nozzle. The nozzle body is provided with a standoff member which is adapted to ride on a portion of the workpiece and which projects beyond the nozzle tip by a distance sufficient to hold the nozzle off of the workpiece by the desired standoff distance.

Abstract: A process for the production of reinforced refractory composite structures which may be of high density and shaped in desired three dimensional configurations. The shaped composite structures are produced by forming a suspension of particulate materials including a colloidal refractory power, colloidal sintering aid, and refractory reinforcement whiskers in a carrier liquid. The colloidal suspension is conformed to a desired configuration and brought into contact with a semipermeable membrane. A pressure is imposed on the suspension in the desired configuration to expel liquid from the suspension through the membrane to arrive at a green composite having a density of at least 40% of theoretical density. After drying, the green composite is then sintered under conditions to form an intergranular liquid phase in the composite providing further densification. A specific composite is a silicon carbide reinforced silicon nitride composite.

Abstract: A temperature sensitive data storage element is disclosed, suitable for application in an erasable optical read/write data storage system. The data storage element includes an optical tuning film and a film of thermochromic phase change material which will change from a first phase to a second phase at temperatures in excess of an upper temperature and back to the first phase at temperatures below a lower temperature. In one application, a thermally controlled support member may be employed to temporarily lower the temperature on the storage element to a point below the lower temperature, thereby initializing the element. In one embodiment, the storage element is a planar, suitably circular disk. In use, the storage element is adapted to be initialized by a modulated laser beam which may be focused on the storage element to temporarily heat particular portions of the element to a temperature in excess of the upper temperature, causing a phase change.

Abstract: A radiographic image is formed of a workpiece irradiated by neutron or X-ray energy. A radiophosphorescent screen is positioned adjacent the workpiece to form a scintillation pattern. The radiation may consist of thermal neutrons radiation from which gamma radiation has been substantially removed. The image is stored upon the semi-conductor target of a television camera.

Abstract: In a method of installing a septum (18) at a desired depth within a section of honeycomb core (12) for use in a sound attenuation panels, the septum is sandwiched between two layers (20, 24) of support material having a melting temperature intermediate between the fusing and curing temperatures of the septum material. The honeycomb core (12) is pressed into supporting materials and septum to segment and position the septum (18) therein, after which the resultant assembly is heated sufficiently to allow the septum to fuse and adhere to the honeycomb core. The resultant assembly is then heated sufficiently to melt the support material and allow it to be drained away, leaving the segmented septum (18) in place within the honeycomb core.

Abstract: A pressure sensitive film display is disclosed having a piezoelectric substrate and a thin film of pressure sensitive phase change material disposed thereon. A film of pressure sensitive material such as samarium sulfide is deposited on a piezoelectric substrate and exhibits a marked increase in reflectance at a region thereof subjected to a pressure in excess of a selected threshold pressure. Three interdigital surface acoustic wave transducers are provided along three edges of the display and are utilized to produce selective surface acoustic wave pulses in the surface of the film. Each surface acoustic wave pulse generates an area of pressure such that an external pressure greater than the selected threshold pressure is generated only at each point where three surface acoustic wave pulses intersect.

Abstract: A random access memory device is disclosed which utilizes phase change materials. The memory device includes two overlapping films of a phase change material which exhibits an optically discernible phase change at any portion thereof which is subjected to a selected external stimulus and which exhibits a hysteresis effect such that any such portion is substantially unchanged after the external stimulus is removed. Various phase change materials are disclosed which respond to changes in pressure, temperature or electric field intensities to vary the transmission characteristics of a selected portion of a film of such material from substantially opaque to translucent. One of the two overlapping films is then utilized to record digital data by changing the phase of the material at selected portions thereof.

Abstract: Disclosed is a method of making carbon/carbon composites by pyrolytic conversion of a carbonizable liquid in a pre-formed graphite body to form an amorphous carbon reinforcing matrix. Graphite fabric saturated with a carbonizable liquid is formed into the shape of the desired end product body and placed in a flexible bag. The bag is evacuated to compress the formed body and the bagged body subjected to external pressure and heated. When the carbonizable liquid is heated to the curing temperature, the external pressure is reduced, causing volatile materials in the liquid to expand and form an interconnected pore structure. The formed body is thereafter heated to a temperature in excess of the curing temperature to further remove volatile materials therefrom. The cured rigid body is then transferred to a pyrolyzing furnace and rapidly heated in an inert gaseous environment directly to about 1500.degree. F. to pyrolyze the carbonizable material and form an amorphous carbon matrix.

Abstract: A dynamic infrared scene projector for presenting cinematic, two-dimensional, spatially distributed scene data to an infrared sensor is provided comprising programmable, thermoptic infrared modulators which exploit thermally-induced changes in the infrared optical properties of a thin film of vanadium dioxide. Because of a hysteresis in the vanadium dioxide material, a stored scene can be created in the modulators by scanning a focused modulated visible or near-infrared laser beam across the thin film while it is thermally biased in the hysteresis loop. The scene is projected into the sensor by placing the modulators between an infrared source/condenser system and a system of projection optics. Dynamic scene projection is accomplished by an erase/rebias system and an optical framing switch to yield a flicker-free output. Erasing of the optical modulator is accomplished by momentarily cooling the VO.sub.2 film to a temperature below the hysteretic loop.

Abstract: In an optical radar system a coherent signal is transmitted at a variable position and the return signal, that is, the reflected portion of the coherent signal is received and coherently detected. The transmitter utilizes a scanning laser having an electron beam that impinges upon a variable reflectance mirror that terminates one end of an optical cavity. An oscillating mode is generated within the resonant cavity when the electron beam locally heats the surface of the variable reflectance mirror to create a pixel that reflects light in a diffracted pattern. The receiver utilizes a stable single mode laser to illuminate a variable reflectance surface. A receiver electron beam generates a plurality of receiver pixels at various positions. The diffracted light from each pixel generates a plurality of variable angle local oscillator beams that are summed with the return signal at a beamsplitter. The output of the beamsplitter is applied to the surface of a detector array.

Abstract: An optical processing system for processing infrared information prior to detection. In one embodiment, optical information from an infrared scene is focused by optics (10) onto a thermoptic modulator (12) which contains an optical structure (16) disposed on the faceplace of a cathode ray tube. The modulator is normally nonreflective of infrared energy from the scene incident thereon. Reflecting spots (22) written on the modulator by an electron beam reflect a portion of the scene to a detector (52) which generates a signal representative of the radiance of the scene element sampled. A series of first and second reflecting spots of different size are written at selected coordinates on the modulator. The respective signals generated by the detector for each spot of the pair are subtracted to provide a spatial band pass filtered signal for each sampling coordinate on the modulator.

Abstract: An actuator (10) for effecting relative pivotal movement between two structures (12, 14) includes a bent beam member (18) having a first portion (20) rotatably secured to one structure and a second portion (22) supported for rotation and eccentric revolution by a housing (42) grounded to the other structure. Index gears (64, 66) assure eccentric revolution of the beam member (18) in an opposite direction in response to rotation of the bent beam member to produce relative pivotal movement between the structures (12, 14). In the first two embodiments, the actuators (10, 120) incorporate internal hydraulic or electric drive arrangements. In other embodiments, the actuators (150, 172, 250, 270) employ various planetary type gear arrangements to achieve even greater mechanical advantage. In the last embodiment, both portions (304, 306) of the bent beam member (302) of the actuator (300) are driven and supported for eccentric revolution.

Abstract: In an optical radar system a coherent signal is transmitted at a variable position and the return signal, that is, the reflected portion of the coherent signal is received and coherently detected. The transmitter utilizes a scanning laser having an electron beam that impinges upon a variable reflectance mirror that terminates one end of an optical cavity. An oscillating mode is generated within the resonant cavity when the electron beam locally heats the surface of the variable reflectance mirror to create a pixel that reflects light in a diffracted pattern. The receiver utilizes a stable single mode laser to illuminate a variable reflectance surface. A receiver electron beam generates a plurality of receiver pixels at various positions. The diffracted light from each pixel generates a plurality of variable angle local oscillator beams that are summed with the return signal at a beamsplitter. The output of the beamsplitter is applied to the surface of a detector array.

Abstract: A method and apparatus for generating a plurality of secondary directional modes within the resonant cavity of a scanning laser oscillator. A first directional mode is generated by directing an electron beam on a variable reflectance end reflector to create a variable position pixel. A pattern of fixed reflectance material is positioned on the surface of the variable reflectance end reflector to generate the secondary directional modes within the resonant cavity. The oscillation threshold for the secondary directional modes is higher than the first directional mode, thereby allowing the first directional mode to have priority over the second directional modes. The second directional modes occupy the regions of the active laser medium of the resonant cavity not occupied by the first directional mode thereby suppressing the gain of the laser medium therein.

Abstract: A circuit for controlling the position of a driven member is disclosed which includes a control circuit for controlling the application of electrical power to a motor and a circuit element operable for generating position error signals corresponding to the position of the load which may in one embodiment constitute a rotor element of the motor. A comparator section is provided for comparing the position error signals with position reference signals and for generating control signals to effect rotation of the load in a desired direction. In one embodiment, the error signal is generated by a feedback loop including a potentiometer having a movable element coupled to the load or motor rotor, wherein the voltage magnitude of the error signal is varied in accordance with the rotational position of the load or rotor element. In a preferred embodiment, the comparator section includes first and second comparators respectively responsive to position deviations of the rotor in first and second rotational directions.

Abstract: Composite protective coatings for protecting carbonaceous substrates from degrading in oxygen containing environments are provided. The composite protective coatings include a first coating layer applied to the surface of the substrate. The first coating layer is a silicon carbide type coating. The second coating layer is applied to the surface of a first coating layer and is a sputter deposited phase stabilized zirconium oxide having a columnar microstructure. Carbonaceous substrates having the composite protective coatings are able to withstand temperatures of about 4100.degree. F. in oxygen containing environments.

Abstract: A septum (18) is installed at a desired depth within a section of honeycomb core (12) for use in a sound attenuation panels, the septum is sandwiched between two layers (20, 24) of support material having a melting temperature intermediate between the fusing and curing temperatures of the septum material. The honeycomb core (12) is pressed into supporting materials and septum to segment and position the septum (18) therein, after which the resultant assembly is heated sufficiently to allow the septum to fuse and adhere to the honeycomb core. The resultant assembly is then heated sufficiently to melt the support material and allow it to be drained away, leaving the segmented septum (18) in place within the honeycomb core.

Abstract: An image processing system is disclosed wherein information corresponding to a selected geographical region or geometric system is stored and selectively retrieved and processed to reproduce images corresponding to selected portions of the geographical or geometric system. In a preferred embodiment, the information is initially recorded photographically and subsequently stored in a digital recording system. Processing, memory, and control systems are employed for producing video signals to be provided to video display units, for producing simulated real time images corresponding to the selected portion of the geographical or geometric system.

Abstract: An aircraft propulsion system is disclosed having an exhaust nozzle structure having an exhaust deflection structure extending within an exhaust duct to direction exhaust flow along selected flow paths. In its preferred embodiment, the exhaust deflection structure is a variable geometry deflection structure having a distal end portion which is movable, relative to adjacent aircraft structure, within an exhaust duct whereby the exhaust deflection structure is positionable as an extension of an upper, aft wall portion of the exhaust duct. In the preferred embodiment, the exhaust nozzle structure includes a guide structure or nozzle segment, connected to the exhaust deflection structure, which is translatably mounted to adjacent aircraft structure for permitting fore and aft movement of the nozzle segment along the aircraft structure.

Abstract: A relatively light weight, low cost compact safety light which may be worn or carried by athletes such as joggers, runners, cyclists, etc. is provided. The safety light is comprised of a light source coupleable to a battery power supply by a position sensitive switch which is sensitive to movement of the athlete and provides intermittent bursts of light which are highly visible to oncoming cars. In one embodiment, the light source is comprised of a light emitting diode coupled to one or more pen light batteries by a position sensitive switch such as a mercury switch. One or more lense members are provided to increase the visibility of the light generated by the light source. A first reflective means located within the safety light housing is utilized to reflect the light generated by the light source through the lense member while a second reflective means located on the outside of the housing provides additional reflectivity for the light generated by oncoming cars.