Abstract: A method for the reactivation of a tin oxide-containing catalyst of a CO.sub.2 laser is provided. First, the catalyst is pretreated by a standard procedure. When the catalyst experiences diminished activity during usage, the heated zone surrounding the catalyst is raised to a temperature which is the operating temperature of the laser and 400.degree. C. for approximately one hour. The catalyst is exposed to the same laser gas mixture during this period. The temperature of the heated zone is then lowered to the operating temperature of the CO.sub.2 laser.

Abstract: A quick actuating closure for a pressure vessel 80 in which a wedge ring 30 with a conical outer surface 31 is moved forward to force shear blocks 40, with conical inner surfaces 41, radially outward to lock an end closure plug 70 within an opening 81 in the pressure vessel 80. A seal ring 60 and a preload ramp 50 sit between the shear blocks 40 and the end closure plug 70 to provide a backup sealing capability. Conical surfaces 44 and 55 of the preload ramp 50 and the shear blocks 40 interact to force the seal ring 60 into shoulders 73 and 85 in the end closure plug 70 and opening 81 to form a tight seal. The end closure plug 70 is unlocked by moving the wedge ring 30 rearward, which causes "T"-bars 32 of the wedge ring 30 riding within "T" -slots 42 of the shear blocks 40 to force them radially inward. The end closure plug 70 is then removed, allowing access to the interior of the pressure vessel 80.

Abstract: At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T.sub.1 phase (Al.sub.2 CuLi). This addition enhances the nucleation of the precipitate T.sub.1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell Hardness values and confirmed by standard tensile tests.

Abstract: An almond shaped radar cross-section test body for use in microwave anechoic chambers, which exhibits a large dynamic scattered field over large angular regions.

Abstract: A safety door latch, which can be simply and quickly disengaged in the event of an emergency, has an elongated keeper plate, which is secured to the inside of the stile of a door in proximity to the edge of the stile and substantially perpendicular thereto. An elongated slide, which is received by and releasably retained within the keeper plate, has an elongated slot therein for releasably securing a chain thereto. The proximal end of the slide is positioned within the keeper plate near the edge of the stile, and the distal end of the slide, which terminates in a clasp, is positioned within the keeper plate away from the edge of the stile. A chain is anchored at one end thereof to the striker jamb of the door and has a pin secured to the other end thereof for insertion into the slot and releasable retainment therein.

Abstract: New polyphenylquinoxalines have been prepared from the reaction of novel bis(.alpha.-diketones) with aromatic bis(o-diamines). These polyphenylquinoxalines have lower glass transition temperatures and melt viscosities and consequently better processability than known polyphenylquinoxalines. The properties of these new polyphenylquinoxalines (tensile strength, modulus, elongation, adhesive strength, fracture energy, and solvent resistance) are comparable with the properties of known polyphenylquinoxalines.

Abstract: An apparatus 10 for effecting sealing of a fused quartz ampoule 24 while maintaining a vacuum on the ampoule via system 12 is disclosed. A plug 28 of fused quartz is lowered into the vertically disposed ampoule 24 (while maintaining the vacuum thereon) and heat sealed therein to prevent any vapor escape from, or contamination of, the contained semiconductor growth charge 29 during subsequent semiconductor crystal growth processes. A rotary vacuum feed-through mechanism 16 selectively rotates axle 34 and spool 32 to unwind wire 30 for lowering of plug 28 into the reduced diameter portion 24b of ampoule 24. Ampoule 24 is hermatically connected to vacuum housing 18 by quick release flange 20 wherein O-ring 22 retains ampoule 24.

Abstract: This invention relates to airfoils which have particular application to rotors of helicopters and rotorcraft and to aircraft propellers. Two airfoil profiles, the RC(4)XX and RC(5)XX are shaped to permit (1) the development of high air loads without causing an extensive separation of the boundary layer air, (2) a distribution of airloads which results in a near zero pitching moment coefficient about the quarter chord for a range of lift coefficients from -0.2 to 1.0 for Mach numbers up to 0.63, and (3) the development of a local supersonic flow field which is so shaped that the wave losses are minimal until higher free stream Mach numbers over a range of lift coefficients from 0.0 to 0.30. Thus, both airfoils have high maximum lift coefficients, low pitching moment coefficients, and high drag divergence Mach numbers to result in improved rotor or propeller performance. The two invention airfoils are related in shape and purpose.

Abstract: Disclosed is a method of visualizing laminar to turbulent boundary layer transition, shock location, and laminar separation bubbles around a test surface. A liquid crystal coating is formulated using an unencapsulated liquid crystal operable in a temperature bandwidth compatible with the temperature environment around the test surface. The liquid crystal coating is applied to the test surface, which is preferably pre-treated by painting with a flat black paint to achieve a deep matte coating, after which the surface is subjected to a liquid or gas flow. Color change in the liquid crystal coating is produced in response to differences in relative shear stress within the boundary layer around the test surface.

Abstract: The synthesis and characterization of several polyenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60.degree.-130.degree. C. in m-cresol at (w/w) solids content of 8-26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. The polymers exhibited T.sub.g s as high as 235.degree. C. and weight losses of 14% after aging at 232.degree. C. in circulating air for sixty hours.

Abstract: Cryogenic foam insulation 20 is adhesively bonded to the outer wall of the fuel tank structure 10. The cryogenic insulation 20 includes square sheets 12 fabricated from an array of abutting blocks 14. Each block 14 includes a sheet of glass cloth 18 adhesively bonded between two layers of polymethacrylimide foam 16. Each block is wrapped in a vapor impermeable membrane 24, such as a polyimide-aluminum-polyimide composite laminate, to provide a vapor barrier. Very beneficial results are obtained by employing the present invention in conjunction with fibrous insulation 28 and an outer aeroshell 30, which is a hot fuselage structure having an internal thermal protection system.

Abstract: A porous plug (10) is provided for the reduction or elimination of positive error caused by orifice (20) during static pressure measurements of airfoil (14). The porous plug (10) is press fitted into orifice (20), thereby preventing error caused either by fluid flow (30) turning into the exposed orifice (20) or by fluid flow (30) stagnating at the downstream edge (21) of orifice (20). In addition, porous plug (10) is flushed with the outer surface of airfoil (14), as by filing and polishing, to provide a smooth surface which alleviates error caused by imperfections in orifice (20). Porous plug (10) is preferably made of sintered metal, which allows air to pass through the pores, so that static pressure measurements can be made by remote transducers (not shown).

Abstract: A corrugated panel structure for supporting compressive loads includes curved cap strips 22 separated by truss-core web segments 30. The truss-core web segments 30 are formed from first and second flat panels 32 and 34 with a corrugated filler 36 therebetween. The corrugated filler 36 extends in the direction of the compressive load, thereby providing load carrying capability for the compressive load. As a result, all components of the panel structure have a compressive load carrying capability resulting in a high strength-to-weight ratio when the compressive load is limiting.

Abstract: An ultrasonic depth gauge 20 for liquids under high pressure is comprised of a transducer assembly 21 and a supporting electronics unit 22. The transducer assembly is mounted into the bottom wall of a storage vessel 12 with its resonating surface directly exposed to the highly pressurized liquid 13 in the vessel. The transducer assembly consists of a conventional transducer element 38 rigidly bonded to the inside wall of a bored out conventional high-pressure plug 30 thereby forming a composite resonator 50. The element and the plug wall resonate as one upon electrical excitation of the element while the transducer element is completely shielded from any exposure to the liquid under high pressure. The composite resonator sends a vibration up to the surface of the liquid where it is reflected back to the composite resonator. The supporting electronics unit measures the vibration round-trip transit time which is proportional to the depth 15 of the liquid.

Abstract: A method is provided to bond strain gauges 6 to various materials. First, a tape 9 with an adhesive backing 10 is placed across the inside of fixture frame 8. Strain gauge 6 is flatly placed against adhesive backing 10 and coated with a thin, uniform layer of adhesive 5. Tape 9 is then removed from fixture frame 8 and placed, strain gauge side down, on the material to be tested. If the material is a high reluctance material 12, induction heating source 20 is placed upon tape 9. If the material is a low reluctance material 13, a plate 23 with a ferric side 21 and a rubber side 22 is placed, ferric side down, onto tape 9. Induction heating source 20 is then placed upon rubber side 22. If the material is an insulator material 14, a ferric plate 7 is placed on tape 9. Induction heating source 20 is then placed on ferric plate 7.

Abstract: Gastrointestinal disorders, especially those in the very young and the very old which are manifested by nausea, vomiting, diarrhea, increased flatus, cramping, and the like, are treated by the oral administration to the patient of a therapeutically-effective amount of an aqueous extract of oatmeal. This extract is especially effective in the treatment of infant colic and infant intolerance of milk and synthetic formulas.

Abstract: An ice detector 11 is provided for the determination of the thickness of ice 22 on the outer surface 12 on an object (e.g., aircraft 10) independently of temperature or the composition of the ice 22. First capacitive gauge 16, second capacitive gauge 18, and temperature gauge 20 are embedded in embedding material 14 located within a hollowed out portion of outer surface 12. This embedding material 14 is flushed with outer surface 12 to prevent undesirable drag. First capacitive gauge 16, second capacitive gauge 18, and temperature gauge 20 are respectively connected to first capacitance measuring circuit 24, second capacitance measuring circuit 26, and temperature measuring circuit 28. The geometry of first and second capacitive gauges 16 and 18 is such that the ratio of the voltage outputs of first and second capacitance measuring circuits 24 and 26 is proportional to the thickness of ice 22, regardless of ice temperature or composition. This ratio is determined by offset and dividing circuit 29.

Abstract: A method and apparatus to measure the thickness of liquid 12 on a surface 14 independent of liquid conductivity. Two pairs of round, corrosion resistant wires, 18 and 20, are mounted in an insulating material 16 such that the cross-sectional area of each wire is flush with and normal to the surface 14. The resistance between each pair of wires 18 and 20 is measured using two AC resistance measuring circuits 22 and 24 wherein the ratio of the outputs of the two resistance measuring circuits is indicative of the thickness of the liquid 12 on the surface 14.

Abstract: A method and device 15 is provided for a quick, accurate and on-line determination of heats of combustion of gaseous hydrocarbons. First, the amount of oxygen in the carrier stream air is sensed by oxygen sensing system 20. Second, three individual volumetric flow rates of oxygen, carrier stream air, and hydrocarbon test gas are introduced into burner 19. The hydrocarbon test gas is fed into burner 19 at a volumetric flow rate n measured by flowmeter 18. Third, the amount of oxygen in the resulting combustion products is sensed by oxygen sensing system 20. Fourth, the volumetric flow rate of oxygen is adjusted until the amount of oxygen in the combustion product equals the amount of oxygen previously sensed in the carrier stream air. This equalizing volumetric flow rate is m and is measured by flowmeter 16. The heat of combustion of the hydrocarbon test gas is then determined from the ratio m/n.

Abstract: A steering system for use in a towing vehicle-trailer combination, wherein all trailer axles are load bearing and fixed. The rearmost axle on the trailer has fixed wheel mountings, and serves as a pivot for turning the trailer when it moves in either a forward or reverse direction. The axle or axles located forward of the rearmost axle of the trailer and aft of the trailer king pin has or have directional wheels that automatically track and follow in concentric pattern the path of the rear wheels of the towing vehicle. The motive force for steering the directional wheels emanates from a sensor nested in the V-slot of the firth wheel of the towing vehicle. The steering system is designed to be installed as a retrofit to existing trailers, or as optional equipment for trailers not yet manufactured. Abling and disabling the system is automatic. Abling takes place when the fifth wheel is moved into position to couple the king pin under the trailer.