Abstract: A method and apparatus for inserting an eddy current hole probe into a hole specimen and automatically moving the probe in two orthogonal (X, Y) directions in response to the impedance change of an eddy current coil located in the probe as a function of distance from the surface of the hole. The probe is centered in the hole by a system controller which operates to minimize the composite deviation value of the coil impedance. The diameter of the hole is then determined from the average impedance measurement. Following this, a plot of the hole eccentricity is generated by determining the impedance deviation from the average coil impedance value as a function of the angular rotation of the probe in the hole. Measurements of the hole eccentricity for a plurality of hole depths provides an indication of the hole eccentricity profile.

Abstract: An antenna, which may be a search coil, is connected to an operational amplifier circuit which provides negative impedances, each of which is in the order of magnitude of the positive impedances which characterize the antenna. The antenna is connected to the inverting input of the operational amplifier, a resistor is connected between the inverting input and the output of the operational amplifier, a capacitor-resistor network, in parallel, is connected between the output and the noninverting input of the operational amplifier, and a resistor is connected from the noninverting input and the circuit common. While this circuit provides a negative resistance and a negative inductance, in series, which appear, looking into the noninverting input of the operational amplifier, in parallel with the antenna, these negative impedances appear in a series loop with the antenna positive impedances, so as to algebraically add.

Abstract: A space spider crane 15 is provided for the movement, placement, and/or assembly of various components on or in the vicinity of a space structure 120. Space spider crane 15 is comprised of a small central body 16 to which manipulators 24 and legs 25 are attached. The legs 25 are equipped with constant pressure gripping end effectors 29 to safely grip space structure 120. Walking by legs 25 or repairing and placing by the manipulators 24 may be controlled either by computer software 140 or a remotely situated human operator 135, who maintains visual contact with the space spider crane via television cameras 22 located at strategic positions on space spider crane 15. One possible walking program consists of a parallel motion walking program that results in small central body 16 alternatively leaning forward and backward relative to end effectors 29.

Abstract: An airborne tracking sun photometer apparatus has a rotatable dome (14). An azimuth drive motor (32) is connected to rotate the dome (14). The dome (14) has an equatorial slot (36). A cylindrical housing (38) is pivotally mounted inside the dome (14) at the equatorial slot (36). A photometer (22) is mounted in the housing (38) to move in the equatorial slot (36) as the housing (38) pivots. The photometer (22) has an end facing outward from the slot (36) with an optical flat transparent window (62). An elevation drive motor (40) is connected to pivot the cylindrical housing (38). The rotatable dome (14) is mounted in bulkhead (18) of an aircraft to extend from the interior (16) of the aircraft. A sun sensor (50) causes the photometer to track the sun automatically. Alternatively, the photometer may be oriented manually (by voltages (117, 119)) or by computer (20).

Abstract: An electro-expulsive system 20 has one or more overlapped conductors OC1-OCN each comprising a flexible ribbon conductor 32 which is folded back on itself. The conductors are embedded in an elastomeric material 33. Large current pulses are fed to the conductors OC1-OCN from power storage units 1-N. As a result of the antiparallel currents I and I', the opposed segments of a conductor 32 are forcefully separated and the elastomeric material is distended. Void 34 in the elastomer aids the separation of the conductor segments. The distention is almost instantaneous when a current pulse reaches the conductor and the distention tends to remove any solid body on the surface of the elastomeric material.

Abstract: 1-[(Diorganooxyphosphonyl)methyl]-2,4- and -2,6-dinitro- and diamino benzenes are prepared by nitrating an (organophosphonyl)methyl benzene to produce The dinitro compounds which are then reduced to the diamino compounds. The organo groups (alkyl, haloalkyl, aryl) on the phosphorus may be removed to give the free acids, (HO).sub.2 P(.dbd.O)--. The diamino compounds may be polymerized with dianhydrides or diacyl halides to produce fire and flame resistant polymers which are useful in the manufacture of aircraft structures.

Abstract: A film-application device (FAD) comprising a pair of exterior, tapered, "O" ring bearing plate members and a central plate member for simplifying the process of thermally bonding a thin dielectric film to a substrate comprising an optical element. In use, the film is sandwiched between the "O" rings and stretched across the optical element by squeezing the exterior plates together before bonding to the element. The film may be used for protecting the optical element or to reduce surface reflection of radiation.The FAD may also be used without the center plate to stretch a dielectric film prior to its attachment to or insertion in a holder to make pellicles or beam-splitters.

Abstract: Solenoid valve (10) has a valve chamber (18) within valve body (12). Inlet and outlet tubes (22) and (24) extend through plate (14) into the chamber (18). Movable core (32) in chamber (18) extends into solenoid coil (30). Distal end (38) of core (32) has a silicone rubber plug (40). Other than when solenoid (30) is energized, compressed spring (48) biases core (32) downward so that surface (44) of the plug (40) is in sealing engagement with ends (26) and (28) of the tubes (22) and (24). Any leak at ends (26) and (28) increases pressure in the chamber (18), resulting in increased sealing force of the plug (40) against the other end (26) or (28). Flow direction through the valve (20) is easily reversed by changing connections to the tubes (22) and (24).

Abstract: A method is disclosed for coating a titanium panel or foil with aluminum and amorphous silicon to provide an oxygen barrier abrogating oxidation of the substrate metal. The process is accomplished with inexpensive procedures common in materials research laboratories, i.e., electron beam deposition and sputtering. The procedures are conducive to treating foil gage titanium and result in submicron layers which virtually add no weight to the titanium. The ultra-thin coatings diffusion bond with the substrate titanium without costly heating steps and the coatings blend with the substrate titanium until separate mechanical properties are subsumed by those of the substrate without cracking or spallation. This method appreciably increases the ability of titanium to mechanically perform in high thermal environments such as those witnessed on structures of space vehicles during re-entry.

Abstract: A weightlessness simulator (10) has a chamber (12) and a suit (56) in the chamber (12). O-rings (26) and valves (30, 38, 42 and 66) hermetically seal the chamber (12). A vacuum pump (32) connected to the chamber (12) establishes a pressure in the chamber (12) less than atmospheric pressure. A water supply tank (34) and water supply line (38) supply a body of water (44) to the chamber (12) as a result of partial vacuum created in the chamber (12). In use, an astronaut enters the pressure suit (56) through port (60), which remains open to ambient atmosphere, thus supplying air to the astronaut during use. The pressure less than atmospheric pressure in the chamber (12) is chosen so that the pressure differential from the inside to the outside of the suit (56) corresponds to the pressure differential with the suit (56) in outer space.

Abstract: The present invention relates to a method of preparing B-trichloroborazine, B.sub.3 N.sub.3 Cl.sub.3 H.sub.3. Generally, the method includes the combination of gaseous boron trichloride in an anhydrous aprotic organic solvent followed by addition of excess gaseous ammonia at ambient temperature or below. The reaction mixture is heated to between about 100.degree. to 140.degree. C. followed by cooling, removal of the solid ammonium chloride at ambient temperature, distillation of the solvent under vacuum if necessary at a temperature of up to about 112.degree. C., and recovery of the B-trichloroborazine. Solvents include, toluene, benzene, xylene, chlorinated hydrocarbons, chlorinated aromatic compounds, or mixtures thereof. Toluene is a preferred solvent. The process provides a convenient synthesis of a material which often decomposes on standing. B-trichloroborazine is useful in a number of chemical reactions, and particularly in the formation of high temperature inorganic polymers and polymer precursors.

Abstract: The subject invention pertains to a novel class of fire- and heat-resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-[(dialkoxyphosphonyl)methyl]-2-4 and -2,6-diaminobenzenes. Typical polymer precursors have the chemical structure: ##STR1## wherein R is alkyl, substituted alkyl or aryl, and R.sup.1 is hydrogen or lower alkyl.The polymer precursors are prepared by reacting 1-[(diorganooxyphosphony)methyl]-2-4- and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-[(diorganooxyphosphonyl)methyl]-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylenebis(4-phenylisocyanate), in a mole ratio 2:1.

Abstract: A swashplate control system (10) has a first gimbal ring (26) pivotally mounted at (32) along a longitudinal axis. A second gimbal ring (24) is pivotally attached at (28) to the first gimbal ring (26) along a lateral axis. A longitudinal cyclic actuator (14) pivots the first gimbal ring (26) along the longitudinal axis. A lateral cyclic actuator (16) pivots the second gimbal ring (24) along the lateral axis. The lateral cyclic actuator (16) is mounted on the first gimbal ring (26). A swashplate (12) is rotatably mounted on the second gimbal ring (24).

Abstract: The subject invention pertains to a novel class of fire- and heat-resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-[(dialkoxyphosphonyl)methyl]-2-4 and -2,6-diaminobenzenes. Typical polymer precursors have the chemical structure: ##STR1## wherein R is alkyl, substituted alkyl or aryl, and R.sup.1 is hydrogen or lower alkyl.The polymer precursors are prepared by reacting 1-[(diorganooxyphosphonyl)methyl]-2-4- and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-[(diorganooxyphosphonyl)methyl]-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylenebis(4-phenylisocyanate), in a mole ratio 2:1.

Abstract: Aminophenoxycyclotriphosphazenes such as hexakis(4-aminophenoxy)cyclotriphosphazene and tris(4-aminophenoxy)-tris phenoxyclyclotriphosphazene are used as curing agents for epoxy resins. These 1,2-epoxy resins are selected from di- or polyepoxide-containing organic moieties of the formula (CH.sub.2 --CHO--CH.sub.2).sub.m --W--R--W--(CH.sub.2 CH--CH.sub.2 O).sub.m where R is diphenyldimethylmethane, diphenylmethane, bis(dibromophenyl)dimethylmethane, or ##STR1## W is a nitrogen or oxygen atom; and m is 1 when W is oxygen and 2 when W is nitrogen. The resins are cured thermally in stages at between about 110.degree. to 135.degree. C. for between about 1 and 10 min, then at between about 175.degree. to 185.degree. C. for between about 0.5 to 10 hr and post-cured at between about 215.degree. and 235.degree. C. for between abut 0.1 and 2 hr. These resins are useful for making fire-resistant elevated temperature stable composites, laminates (e.g.

Abstract: Apparatus for generating a single pulse the first time only that a noisy cyclic signal exceeds a reference level during a half-cycle. For the positive half of a cycle of the noisy cyclic signal, a comparator 12 and a multivibrator 14 produces a fixed voltage output when the noisy cyclic signal first exceeds the reference level. A multivibrator 23 stops the production of the fixed voltage output when the noisy cyclic signal next passes the zero voltage level in the negative direction. Consequently, a single pulse is generated indicating that the signal exceeded the reference level during that half-cycle. Comparator 16 and multivibrator 17 are for producing pulses whenever the noisy cyclic signal exceeds the reference level during the negative half-cycle.

Abstract: A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point.

Abstract: Ultrasonic radio frequency toneburst are launched into a sample of material tested. The amplitude of the tone-bursts and the slope of the resulting static displacement pulses are measured. These measurement are used to calculate the nonlinearities of the material.

Abstract: The difference in dynamic pressure in the propeller slipstreams as measured by sensors 20 and 20a is divided by the freestream dynamic pressure generating a quantity proportional to the differential thrust coefficient. This quantity is used to command an electric trim motor 26 to change the position of trim tab 14 thereby retrimming the airplane to the new asymmetric power condition. The change in position of the trim tab produced by the electric trim motor is summed with the pilot's input to produce the actual trim tab position.

Abstract: An atomizer (10) for a liquid has an air supply tube (20). Liquid supply tubes (26, 28) extend longitudinally along the air supply tube (20). The air supply tube (b 20) has at least one air orifice (22) extending from an inner surface (24) of the tube (20) through the tube. The liquid supply tubes (26, 28) are positioned on either side of the air orifices (22) and the liquid tubes are sealed to the air supply tube. The liquid supply tubes (26, 28) with facing liquid orifices (30) are positioned adjacent each of the air orifices 22. The liquid supply tubes (26, 28) are laterally spaced apart at the liquid orifices (30) a distance less than the diameter of the air orifices (22) to enable a beneficial venturi effect when the atomizer is in operation.