Abstract: An optical erasable disk memory system which utilizes duration modulated laser switching is disclosed. The disk storage system utilizes a disk-shaped storage medium which includes a planar substrate and a thin film of phase change material. A substantially transparent optical tuning layer and protective layer are also utilized in the preferred embodiment of the present invention. The phase change material utilized is sensitive to both stress and temperature variations and will change from a first optically discernible phase to a second optically discernible phase at any portion thereof subjected to a temperature in excess of a selected threshold temperature at a particular stress and will change from the second phase back to the first phase at any portion thereof subjected to a stress in excess of a selected threshold stress at a particular temperature.

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: An apparatus is disclosed for forming elongate structures of composite materials. The apparatus includes a plurality of forming dies for preheating, heating and then cooling an elongate portion of composite material while shaping the material within an internal passage. A pulling device is utilized to continuously draw elongate strips of composite material through the forming dies. The pulling device includes two opposed endless track devices. One of the endless track devices serves to mount a plurality of engagement dogs, each having a substantially flat surface for engagement of the elongate portion of composite material. The other endless track device serves to mount a plurality of pivoting engagement dogs, each having a curvilinear surface wherein increased resistance by said elongate strip of composite material will pivot the curved surface into closer alignment with a corresponding flat surface, thereby tightening the grip of the pulling device on the elongate strip of composite material.

Abstract: A method and apparatus for rapidly erasing and rebiasing a thermoptic thin film. A thermal insulating material (16) is disposed adjacent a thermoptic thin film (10). A layer of resistive material (14) is disposed between the insulating material and the thermoptic thin film and is connected to a current generator (18) which supplies a current to the layer dissipating heat into the thermoptic thin film and insulating layer. A thermal body (22), having high thermal conductivity and interfacing with the insulating layer the opposite boundary from the thermoptic thin film, contains a conduit through which a refrigerated liquid is flowed to establish a thermal gradient from the thermoptic thin film to the fluid. Sufficient current is supplied to the resistive layer to maintain the temperature of the thermoptic thin film at the bias temperature.

Abstract: An erasable optical read/write data storage system is disclosed. The data storage system utilizes a temperature sensitive data storage disk which 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. An environmentally controlled chamber is provided to maintain the data storage disk at a selected bias temperature between the lower and upper temperatures to ensure that no unintentional phase change will occur. A thermally controlled support member is utilized to temporarily lower the temperature of the disk to a point below the lower temperature, thereby initializing the disk. A modulated laser beam is then focused on the disk to temporarily heat particular portions of the disk to a temperature in excess of the upper temperature, causing a phase change.

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: An apparatus for forming composite, fiber/resin components with fibrous, resin-impregnated tape is disclosed. The apparatus employs a gantry for positioning a tape dispensing head assembly over a mold structure, which defines a mold surface of planar or contoured configuration. A control system is employed having sensing devices for generating signals indicative of relative positions of components of the apparatus in several axes of permissible movement, and tape application is effected by means of major and secondary command inputs to appropriate servomotor devices. Primary and initial movement is controlled in accordance with a sequence command program in cooperation with a resident program in a digital computer, and a second, adaptive control system is alternatively employed for enabling the tape dispensing head to follow vertical contours of the mold surface during X-Y movement across the surface.

Abstract: A radiographic imaging system (10) includes first and second housing segments (10a, 10b) with the second housing segment (11b) having a low-light-sensitivity television camera (13) mounted therein. The first housing segment (11a) has a radioluminescent screen structure (20) fitted within an opening (16). A workpiece (24) is positioned adjacent the radioluminescent screen (20) and between the screen and a source of radiation (25a, 25b). The screen structure includes means for producing a scintillation shadowgraph pattern in response to impingement on the screen of radiation directed through the object. The camera (13) has its optical input section directed toward the radioluminescent screen for receiving the scintillation shadowgraph pattern and has a target means for forming charge patterns corresponding to the scintillation patterns produced on the radioluminescent screen and scanning means for scanning the target means to generate an optical signal corresponding to the charge pattern formed on the target.

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: In accordance with the invention, a composition of matter is provided for forming a coating for protecting carbonaceous substrates from degradation at elevated temperatures. The composition of matter is a mixture of particulate silicon, silicon carbide and alumina. The mixture contains between about 40% and 50% silicon by weight of the total composition, between about 30% and 50% silicon carbide by weight of the total composition and between about 20% and 30% alumina by weight of the total composition. A method is provided for forming a primary protective coating on carbonaceous substrates utilizing the aforesaid mixture. An enhancement coating is provided for sealing the primary coating in applications where the substrate will be subjected to elevated temperatures and temperature cycling.

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: In a system for generating thermal (14 MeV) neutrons containing an ionic accelerator, a novel thermal neutron collimator for producing a beam of collimated thermal neutrons is disclosed. The apparatus includes a substantially hollow collimator tube (10) having a closed, neutron permaeable inlet portion (20) communicating with a source of thermal neutrons (12) and an open outlet portion (22) disposed downstream of the inlet portion at the opposite end of the tube. The collimator walls (14,16,18) diverge outwardly toward the outlet portion of the tube and are formed of three radial layers comprising an outer layer of thermal neutron absorbing material (26) for absorbing off-axis thermal neutrons, an intermediate layer of lead (24) for absorbing X-rays and gamma rays and an inside layer of aluminum (23) for structural support.

Abstract: An apparatus is disclosed for forming concave tape wrapped composite structures. The apparatus utilizes a mold having a cylindrical concave surface with a mounting plate mounted for rotation at each end thereof about a point on a longitudinal axis of the concave surface. A longitudinal shaft is mounted to each mounting plate a selected distance from the longitudinal axis and extends parallel thereto. A tape dispenser carriage is mounted to the longitudinal shaft and is movable along the length thereof. A radial shaft is mounted through the tape dispenser carriage such that the longitudinal axis of the radial shaft passes through the longitudinal axis of the concave surface and along a radius of the concave surface.

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 composite material manufacturing process and resulting structure is provided to include high strength material whiskers (20) having a characteristic orientation when placed in an electromagnetic field (22). In one embodiment, whiskers (20) are disposed between lamina (10 and 15) and oriented generally perpendicular to the fiber layers (14 and 18). The whisker (20) orientation is maintained during a curing cycle for the respective matrices (12 and 16) wherein the matrix viscosity allows the whiskers (20) to orient in response to the applied electromagnetic field (22). The whiskers (20) retain their orientation in the resulting laminate to provide improved structural integrity for the laminate.

Abstract: A multiplexed multiplex bus includes a bus controller for controlling the traffic on a multiplex bus network. A plurality of extended buses are stubbed off of one stub on the main bus and are buffered by a series of driver/receivers. Control remote terminals enable one of the extended buses under control of the bus controller for subsequent communication with the main bus. The bus controller can address the control remote terminal to activate one of the extended buses and then address the remote terminals thereon. The remote terminals on all of the extended buses have identical addresses and, as such, are not simultaneously connected to the main bus at any given time.

Abstract: Apparatus for rapidly erasing and rebiasing a thermoptic thin film in the near and medium infrared. A thermal insulating material (56) is disposed adjacent a thermoptic vanadium oxide thin film (50). The insulating layer has high transmittance in the 3-5 or 8-12 micrometer spectral bands. A layer of resistive semiconductor material (54) having high transmittance in the 3-5 or 8-12 micrometer band is disposed between the layer of insulating material and the vanadium oxide thin film. A multilayer dielectric thin film stack is superposed adjacent the vanadium oxide thin film, or is disposed in two parts adjacent the upper and lower surfaces of the thermoptic thin film.

Abstract: A structure capable of being expanded and retracted. The structure includes a pair of cells each including a plurality of leg elements which are pivotally joined at one end to form an apex point and which are pivotally joined at their opposite ends from the apex point connection to the corresponding leg element from the other cell to form a plurality of common base points. The structure also includes a plurality of hinged elements connected between adjacent common base points to thereby form a common base and the hinged elements each have a pair of sections that are connected at a hinge point approximately midway between the adjacent common base points to which the other end of each section is connected.

Abstract: A small caliber guided projectile (20) includes a maneuvering unit (22) having a forward opening inlet (36) which provides diffused air to a flow control mechanism (70) prior to exhausting such air through diametrically opposed exhaust nozzles (74, 76). The flow control mechanism (70) includes a primary flow passageway (78) and an upper orifice switching device (100) for controlling bypass flow to one of the exhaust nozzles (76). An orifice switching device (120) controls bypass flow to the other exhaust nozzle (74). In one embodiment, a small, rearward facing step or other means of vortex generation, such as boundary layer energization, is located upstream of the discharge of the flow through switching devices into the nozzles. When the switching devices are closed, flow over the rearwardly facing steps generates a small vortex which enhances flow attachment as a result of the Coanda effect and increases flow through the nozzle.

Abstract: A circuit for providing controlled switching of power applied to a load is adapted for actuating and deactivating a power switching circuit in response to a command signal. The circuit employs a switching circuit having a time delay section operable to terminate application of power immediately upon the cessation of a control signal and to conduct current after a predetermined delay interval after receipt of a command signal. The circuit is adapted for use with pyrotechnic ignition systems in which it is desired to quickly discharge capacitive elements connected to a load for prevention of undesired and possibly hazardous build-up of heat in a resistive ignition element.