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 system and process for fluid jet cutting of a workpiece providing for self orientation of a catcher vessel. This invention comprises a cutting head adapted to be connected to the robot arm of a robotically controlled cutting system. A nozzle is mounted in the cutting head and adapted to dispense a jet cutting fluid stream along a cutting axis to be directed against a workpiece. The system further comprises a catcher assembly including a bracket supporting a catcher vessel having a receiving aperture. The catcher vessel contains a sacrificial material for dissipation of kinetic energy of the spent jet cutting stream. The supporting bracket includes an arm which depends from the cutting head along a traverse which is laterally offset from the cutting axis.

Abstract: Optical communication system having repeater amplifiers cascaded with plurality of optical star couplers wherein each star coupler is coupled to an associated set of terminals. Each star coupler has two mixing sections serially disposed between its input and output terminal ports. Star couplers receive optical signals from their associated terminals, mix the received signals and retransmit the mixed signals to each terminal in its associated set and to each of the repeater amplifiers. Star couplers also receive amplified signals from the repeater amplifiers, mix the received amplified signal and retransmit the mixed optical signals only to their associated terminals. Star couplers, thus, enable optical signals transmitted by their associated terminals to be transmitted to each terminal in the system without permitting the same signal to be returned to the same star coupler, thereby avoiding the formation of continuous optical loops and hence avoiding the problem of optical lockup.

Abstract: A pre-cast dome-like shell is loaded with a predetermined amount of curable sealant. The sealant and dome are similar in composition. The dome is pressed over the exposed end of a fastener. An elastic portion of the shell can expand, thereby increasing the internal volume of the shell to accommodate small variations in sealant amount. A close fit between the shell and fastener, combined with an adequate shell wall, insure proper shell orientation and barrier thickness.

Abstract: A relative position navigation system and method installed in a first participant for computing the relative position, in range and azimuth, of at least one other participant in the system without using azimuth-sensing apparatus. The system includes ranging apparatus for determining the distance between the first participant and the other selected participant for at least three selected points in time. A processor determines the change in position of the first participant relative to the second participant during the time periods between the first and second, and second and third points in time, and computes the "synthetic" (rather than measured) azimuth coordinate of the selected other participant relative to the first participant at the third point in time as a function of the distance and change in relative position data obtained by the system.

Abstract: A trinary inverter for a digital logic circuit of the type having relatively positive, negative and zero signal voltage values is implemented with CMOS transistors and has the advantages of low power dissipation and low output impedance in the zero signal state. The inverter comprises first, second and third inverter branches, where each branch is formed of a pair of complementary MOS field effect transistors. The inverted output signals from each branch are used to produce a device output signal having the desired voltage transfer characteristics.

Abstract: A modular switching system for connecting a plurality of digital computers to a plurality of computer memories, employing interconnecting digital switching modules. Each module has the capability of recognizing an access request to a computer memory by recognizing a generated address within a range of addresses assigned to that computer memory. The digital switching modules are interconnected with a priority network which permits arbitration between simultaneous requests for access by several digital computers to the same computer memory.

Abstract: The toughness of vanadium and niobium microalloyed medium carbon bar steels is significantly improved by a controlled addition of aluminum in a range of from about 0.05 to 0.11 percent. Forged parts combining high strength and hardness properties with improved toughness can be made from the new bar steel without the need of heat treatment.

Abstract: A method and system for detecting an object hidden behind and/or under various combinations of optical and/or radar camouflage is disclosed. The radar camouflage is made from material having multiple layers of lossy dielectric and supporting fabric. The optical camouflage is made from material having no special electrical properties but is colored to blend with the supporting scenery. Both types of camouflage material are cut in a random pattern of openings or apertures. The space containing the camouflaged object and other radar-reflective objects is radiated with RF energy at a frequency swept over a predetermined band within the K band of radar frequency bands so that the incident RF waves radiate through the apertures and are re-radiated through the apertures after reflection from the object to create an identifiable scintillation in the reflected RF signal and an enhancement of its average reflectivity at certain frequencies within the predetermined band.

Abstract: A method and apparatus are disclosed for converting a digital TACAN output into an analog potentiometer input suitable for an analog navigation computer. The apparatus includes an input register for temporarily storing a digital TACAN output signal. A nines complement generation circuit is utilized to generate the nines complement of the digital TACAN output signal and the nines complement is temporarily stored in a second register. The data in each register is then utilized to control one of two identical resistive circuits which are coupled to a common output node so that the total resistance in both circuits is always equal to a selected total resistance. In a preferred embodiment of the present invention, a plurality of optically coupled solid state relays are utilized to control the resistive circuits.

Abstract: A computerized flight inspection system is disclosed. The system of the present invention may be utilized to generate an accurate reference location with respect to an airport runway for an aircraft having an inertial navigation system. A selected geometric pattern having a highly unambiguous autocorrelation function is placed on at least one end of the runway. A video line scanning camera mounted to the aircraft is then utilized to scan the geometric pattern in a line generally perpendicular to the line of flight. The output of the video line scanning camera is then correlated with a stored reference pattern to generate a signal indicative of the detection of the geometric pattern on the runway. A laser altimeter is mounted to the aircraft and utilized to generate an accurate signal indicative of the aircraft altitude with respect to the runway pattern. The outputs of the correlation circuit and the laser altimeter are then utilized to correct data from the inertial navigation system.

Abstract: A printed circuit for mounting and connecting a plurality of semiconductor devices is disclosed and includes a planar insulating substrate having multiple conductive layers disposed in overlying relationship within the planar substrate. A plurality of parallel rows of apertures for wire wrap, quick connect or stitch wire contacts are provided for mounting integrated circuit. One side of the printed circuit board includes a plurality of power and ground connections disposed between each pair of parallel rows of apertures so that filter capacitors may be mounted under each integrated circuit, thereby conserving printed circuit board space. In a preferred mode of the present invention, alternate ones of the conductive layers are coupled to a source of electrical power while all remaining conductive layers are gounded. At least two adjacent conductive layers are then utilized to minimize parasitic capacitance by completely surrounding each aperture with a portion of conductive material.

Abstract: Method and apparatus for performing eddy current flaw inspection on workpiece material such as steel bar stock. A drive mechanism propels a workpiece longitudinally along a workpiece path. An array of electromagnetic transmitter coils is disposed about the workpiece path. An electromagnetic source energizes the transmitter coils under control of multiplexing circuitry. The multiplexing circuitry and source actuate respective transmitter coils in a predetermined iterative sequence. The sequential actuation induces eddy currents in the workpiece at a succession of locations extending iteratively about the workpiece circumference. Circuitry coupled to multiple, differentially wound sensing coils detects variations in eddy current produced in the workpiece and utilizes these detected variations to produce flaw indicating signals.

Abstract: A tactile sensing tool positioning system for positioning a tool normal to the surface of a curved workpiece is disclosed. The tool positioning system of the present invention includes a steel frame for rigidly supporting a cutting tool having a longitudinal cutting implement, such as a drill bit or countersink bit. The steel frame includes a steel collar which is normal to the axis of the cutting implement and which supports a deformable ring of polyurethane or other resilient material. A plurality of aluminum cylinder positioning sensors are imbedded into the steel collar and surrounded by the deformable ring with one end of each aluminum cylinder positioning sensor contiguous with the exposed surface of the deformable ring. The axial loading experienced by each aluminum cylinder positioning sensor is measured by an associated strain gauge, and a quadrature circuit is then utilized to balance the forces on the aluminum cylinder positioning sensors and normalize the longitudinal cutting implement.

Abstract: A portion of a chalcogenide transformation film in a less reflective phase responds to a low energy laser beam writing pulse by transforming to a crystalline phase. A marmem alloy, secured to the bottom side of the film, responds to a longer erasing pulse of a lower energy laser beam at the same portion by physically stressing the film only at that same portion. The film portion responds to the physical stress by transforming back to a less reflective phase. An optical reader interprets the crystalline phase as a digital logic "1", and the less reflective phase as a digital logic "0".

Abstract: An infrared receiver for detecting a communications signal during a fixed reception period in a high noise environment that includes a sensor having a cooled detector mounted upon a substrate upon the end of a cold well tube that further includes a cooling gas tube having a fixed orifice to emit a cooling gas upon the interior surface of the substrate. The receiver further includes a signal processor that receives the detector signals and determines if the detector signals include prdetermined signal characteristics of the communications signal.

Abstract: A riveting apparatus includes a body pivotable about a horizontal axis and having first and second arms extending therefrom. Riveting structure is provided on the arms for cooperating to install and fasten rivets through a workpiece positioned between the riveting structure. The body may be rotated between a substantially horizontal to a substantially vertical position to accommodate riveting a workpiece having varying contours. The apparatus allows riveting operations to be performed at any point on the workpiece while permitting the operator to position himself immediately adjacent the point of riveting to assure proper alignment of the workpiece and proper riveting thereof.

Abstract: Corrugations are removed from the end of a helically corrugated pipe by compressing the end of the pipe between a plurality of radially movable die segments. By choosing appropriately-shaped die segments and die-actuating cams, the end of the pipe can be expanded, or shrunk to a diameter less than that of an imaginary cylinder defined by a surface of revolution contacting the innermost surfaces of the pipe. Products manufactured in accordance with the method of the invention have an end portion with an accurately controlled diameter; a minimum of pipe length is taken up by the modification.

Abstract: An automated tool positining system is disclosed. The system includes a plurality of work stations, each having a set of guide rails disposed along the length thereof. A single control device is provided and includes a set of guide rails adapted to be temporarily aligned with the guide rails of each work station. The control device is thus movable from work station to work station and operates with a novel tool support member which may be selectively positioned along any guide rail to support a cutting tool at a selected position on a particular work station. The tool support member includes arcuate bearing surfaces which permit the cutting tool to be rotated through a conical section having its vertex at the cutting point of the tool in reponse to the output of a workpiece surface detection circuit. In this manner, the cutting tool may be automatically and accurately positioned normal to the contoured surface of the workpiece.

Abstract: An explosive, fragmentation structure having means for selectively controlling fragment size and configuration. The structure includes an outer casing having an inner surface defining a chamber and further includes means for propagating shock waves across the inner surface from a selected one of two detonation points with the chamber. Means are provided for directing shock waves, propagated from the first detonation point, against the surface in a first pattern of segment-defining lines and for directing shock waves, propagated from the second detonation point, against the surface in a second pattern of lines which define segments larger than those of the first pattern.