Abstract: 1-[(Diorganooxyphosphonyl)methyl]2,4- and -2,6-diamino benzenes are reacted with polyacylhalides and optionally comonomers to produce polyamides which have desirable heat and fire resistance properties. These polymers are used to form fibers and fabrics where fire and flame resistance properties are important, e.g., aircraft equipment and structures.

Abstract: A rubber-toughened addition-type polyimide composition having excellent high temperature bonding characteristics in the fully cured state and improved peel strength and adhesive fracture resistance physical property characteristics is disclosed. The process for making the improved adhesive involves preparing the rubber-containing amic acid prepolymer by chemically reacting an amine-terminated elastomer and an aromatic diamine with an aromatic dianhydride with which a reactive chain stopper anhydride has been mixed, and utilizing solvent or mixture of solvents for the reaction.

Abstract: A gas turbine engine fuel delivery and control system is provided with means to recirculate all fuel in excess of fuel control requirements back to the aircraft fuel tank, thereby increasing the fuel pump heat sink and decreasing the pump temperature rise without the addition of valving other than that normally employed. A fuel/oil heat exchanger and associated circuitry is provided to maintain the hot engine oil in heat exchange relationship with the cool engine fuel. Where anti-icing of the fuel filter is required, means are provided to maintain the fuel temperature entering the filter at or above a minimum level to prevent freezing thereof. In one embodiment, a divider valve is provided to take all excess fuel from either upstream or downstream of the fuel filter and route it back to the tanks, the ratio of upstream to downstream extraction being a function of fuel pump discharge pressure.

Abstract: The invention is directed to a screen anode for an ion thruster. The anode is constructed of a woven mesh screen, preferably of a stainless steel wire cloth with a mesh size less than the intergrid gap or openings of the screen grid or accelerator grid systems of the ion thruster. The screen anode is sputter coated with tantalum as a result of thruster operation. Because of the fineness of the screen anode any spalled material from the tantalum coated anode is in such small dimensions that the spalled pieces cannot interfere with the accelerator and screen grid systems and with the focusing therebetween.

Abstract: An apparatus and method for calibrating high temperature strain gases which serve for both dead weight and constant deflection measurements. A cantilever support arm allows the test unit to slide into a furnace while one end is subjected to bending strain either by hanging weights upon it or by deflecting it with a push rod. The dual nature of the fixture permits both tests to be run without change of the test specimen or removal from the furnace.

Abstract: A continuous HCl in-air indicator consists of a tube-like element with an inlet end through which a continuous stream of air, containing HCl, enters. The air flows downstream from the inlet end and exits the element's outlet end. Positioned between the element's inlet and outlet ends are first and second spaced apart photoelectric units, which are preferably positioned adjacent the inlet and outlet ends, respectively. Ammonia gas is injected into the air, flowing through the element, at a position between the two photoelectric units. The ammonia gas reacts with the HCl in the air to form ammonium chloride particles. The difference between the outputs of the two photoelectric units is an indication of the amount of HCl in the air stream.

Abstract: This invention employs a magnetometer as a magnetic heading reference for a vehicle such as a small aircraft. The magnetometer is mounted on a directional dial in the aircraft in the vicinity of the pilot such that it is free to turn with the dial about the yaw axis of the aircraft. The invention includes a circuit for generating a signal proportional to the northerly turning error produced in the magnetometer due to the vertical component of the earth's magnetic field. This generated signal is then subtracted from the output of the magnetometer to compensate for the northerly turning error.

Abstract: A method and apparatus is described for compensating for reflection losses in an optical path length modulated absorption-absorption gas analyzer used for determining the density of a reference gas in an unknown gas sample. The apparatus comprises a first chamber for containing a first gas including a reference gas at a known partial density and a second chamber for containing a second gas including a sample of the reference gas at an unknown partial density. A source of radiant energy is provided for passing radiant energy through the first and second chambers. Means are provided for modulating the path length of the radiant energy in the chambers. Additionally, a chopper wheel comprising a plurality of gas cells containing a sample of the reference gas is interspersed by a plurality of gas cells containing a gas excluding the reference gas.

Abstract: An exhaust nozzle for a jet aircraft provides jet noise suppression. The nozzle includes a plurality of coaxial airfoil ring segments which are spaced serially along the longitudinal axis of the nozzle to define a plurality of annular coaxial channels therebetween. The diameters of the segments progressively decrease downstream along this axis and the exits of the channels are non-coplanar. The radial depths of the channels are small as compared with the axial distance between adjacent channel exits so that noise is emitted non-simultaneously from the channel exits as a series of weakened pulses staggered in time. The boattail angles of the outer surfaces of the ring airfoil segments increase in magnitude with increasing distance downstream to reduce drag.

Abstract: A process for the preparation and isolation of high purity anhydrous lower valence state metal halides comprising dissolving the corresponding higher valence state metal halide of the desired lower valence state metal halide in an organic liquid, which is selected such that the higher valence state metal halide is soluble therein and the lower valence state metal halide is insoluble therein, and subjecting the solution to high energy radiation which reduces the higher valence state metal halide to its corresponding lower valence state metal halide, at a temperature in the range of from about 0.degree.C. to about room temperature.

Abstract: A network is disclosed for automatically checking the skew and character spacing of digital tape drive systems to indicate out-of-tolerance conditions of those parameters. The network enables a tape drive to check its own recording accuracy as well as that of tapes recorded on other drives. In operation, the first detected pulse of each character triggers a monostable multi-vibrator which locks out further data pulses and initiates a window pulse equal in length to the maximum permissible skew. At the end of the window pulse data pulses may again be received. If a pulse is received after termination of the window pulse, the skew is determined to exceed specifications and a skew error indication is given by the illumination of a display light, for example. A similar circuit arrangement is provided for detecting character spacing which is less than the minimum required for unambiguous data reproduction.

Abstract: A cyclic therapeutic hand exerciser based on inflation and deflation of structural members, which alternately imparts a straightening and a bending motion to the fingers wherein as air pressure inflates a splint-like upper member the fingers are straightened and upon deflation of the splint-like member and inflation of a wrist pouch a flap is tightened pulling the fingertips down and curling the fingers in toward the palm.

Abstract: An antenna system for single or plural beams providing continuously variable beamwidth selectively in one or both of two orthogonal senses, i.e., azimuth and elevation, for either communications or angle-tracking. The system includes two parabolic cylindrical reflectors, which are respectively a main reflector and a sub-reflector; the reflectors are positioned with the focal axes thereof orthogonally. A point or multibeam (e.g., monopulse) feed is mounted adjacent the main reflector on the focal axis of the sub-reflector in the Airy disc of the system. Beamwidth is controlled using telescoping sections on the main and sub-reflectors to control the size of the surface areas thereof. Simultaneous operation of the telescoping sections of the reflector and sub-reflector provides bidirectional zooming of the beam without distortion while individual operation of the sections of the reflectors permits unidirectional zooming.

Abstract: A space-to-space or space-to-earth optical transmission link is simulated by positioning a linear optical modulator between an optical carrier source and a receiver for the carrier. The optical modulator is driven by an analog signal having random variations indicative of characteristics of the transmission link, as derived from an analog computer circuit. The analog computer circuit is responsive to a Gaussian random analog source. For certain types of links, the analog computer circuit is responsive to a pair of Gaussian analog signals which are derived by feeding a relatively wide band Gaussian analog source in parallel to a first low pass filter and to a heterodyne circuit that derives a beat frequency output that is passed through a second low pass filter having the same characteristics as the first low pass filter. For space-to-space transmission, transmitter pointing jitter is a dominant noise source and is simulated by deriving a beta statistical variation from the analog computer.

Abstract: An axially controllable magnetic bearing apparatus provides radial stiffness force control between a rotor and stator. The bearing includes a pair of axially spaced air gaps defined by corresponding pairs of annular pole pieces of the rotor and stator. Permanent magnets carried by the rotor generate constant axial bias fluxes in each of the air gaps. A pair of coils, disposed to axially excite the air gaps with variable flux, are driven in a manner so that the sum of the total fluxes in each of the air gaps is varied to change the radial stiffness between the bearing rotor and stator. Axial force between the rotor and stator is produced by exciting the two coils to vary the difference of the total air gap fluxes. The pair of coils are driven in a bridge circuit by pulse-width modulated signals.

Abstract: An auger device is used to attach rigidized surface insulation to a spacecraft. The auger is preferably screwed into an insulation tile which has been predrilled. The augertile combination is then fastened to the spacecraft using an attachment screw which penetrates the spacecraft skin and which is secured by a blind end fastener. In an alternate method, the auger is incorporated in the insulation tile when the latter is fabricated.

Abstract: An apparatus for measuring the velocity of a vehicle traveling between first and second measured points. The apparatus includes a cylindrical housing having an open top for receiving a transparent disk. Indicia representing speed calibrations is circumferentially spaced adjacent an outer perimeter of the disk. A stopwatch is carried in the housing below said disk and has a rotatable hand which rotates at a predetermined rate under the indicia. A lamp is carried below the stopwatch for illuminating the indicia carried on the transparent disk. The stopwatch is started when the vehicle passes a first reference point and stopped when the vehicle passes the second reference point. Thus, when the hand is stopped, such points to the calibrated indicia on said disk indicating the velocity of a vehicle.

Abstract: This invention is method and apparatus for measuring, at a remote location, the concentration and velocity of SO.sub.2 in plume from a smokestack. An ultraviolet video system views the plume against the background sky at wavelengths where SO.sub.2 molecules absorb light. The result is a real time display of the plume coupled with means for measuring the SO.sub.2 concentration at any point in the plume and at any time desired. In addition, means are provided in combination with the ultraviolet video system for measuring the velocity of the SO.sub.2 in the plume.

Abstract: A high voltage distributor allowing the easy connection and disconnection of a high voltage power supply to and from one or more circuits requiring the supply. The design configuration features unrestrained "pump-out," insulation of the high voltage from ground, and freedom from corona. These features are obtained by mounting a removable retaining rod on one or more insulators, thereby facilitating the support by the retaining rod of a plurality of washers. One of the washers is integrally connected to the high voltage power supply while the remaining washers are integrally connected to the circuits requiring the high voltage.