Abstract: A test apparatus and method of its use for evaluating various performance aspects of a test specimen is disclosed. A chamber within a housing contains a cold mass tank with a contact surface in contact with a first surface of a test specimen. The first surface of the test specimen is spaced from the second surface of the test specimen by a thickness. The second surface of the test specimen is maintained at a desired warm temperature. The first surface is maintained at a constant temperature by a liquid disposed within the cold mass tank. A boil-off flow rate of the gas is monitored and provided to a processor along with the temperature of the first and second surfaces of the test specimen. The processor calculates thermal insulation values of the test specimen including comparative values for heat flux and apparent thermal conductivity (k-value). The test specimen may be placed in any vacuum pressure level ranging from about 0.01 millitorr to 1,000,000 millitorr with different residual gases as desired.

Abstract: Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

Abstract: A universal interface adapter circuit interfaces, for example, a wireless communications headset with any type of communications system, including those that require push-to-talk (PTT) signaling. The interface adapter is comprised of several main components, including an RF signaling receiver, a microcontroller and associated circuitry for decoding and processing the received signals, and programmable impedance matching and line interfacing circuitry for interfacing a wireless communications headset system base to a communications system. A signaling transmitter, which is preferably portable (e.g., handheld), is employed by the wireless headset user to send signals to the signaling receiver. In an embodiment of the invention directed specifically to push-to-talk (PTT) signaling, the wireless headset user presses a button on the signaling transmitter when they wish to speak. This sends a signal to the microcontroller which decodes the signal and recognizes the signal as being a PTT request.

Abstract: A method for joining a woven flexible ceramic fabric and a thin metal sheet creating an integral metal surfaced flexible thermal protection article, which method comprises:placing multiple dots of high temperature metallic or ceramic brazing material between the flexible ceramic fabric and the thin metal sheet in a random or organized pattern, with the proviso that the brazing material covers about 10% or less of the surface of one flat side of the metal sheet;heating the flexible ceramic fabric, brazing material and thin metal sheet for a predetermined period of time to integrally connect the same; andcooling the formed flexible article to ambient temperature. Preferably the flexible ceramic is selected from fibers comprising atoms of silicon, carbon, nitrogen, boron, oxygen or combinations thereof. The flexible thermal protection article produced is also part of the present invention. The thin metal sheet is comprised of titanium, aluminum, chromium, niobium or alloys or combinations thereof.

Abstract: A method is provided for closing out the edges of a flexible ceramic insulation member including inner and outer mold line covering layers. A rigid, segmented, ceramic frame is placed around the edges of the insulation member and exposed edges of the inner and outer mold line covering layers are affixed to the ceramic frame. In one embodiment wherein the covering layers comprise fabrics, the outer fabric is bonded to the top surface and to a grooved portion of the side surface of the frame. In another embodiment wherein the outer cover layer comprises a metallic foil, clips on the edges of the frame are used to engage foil extensions. The ceramic frame is coated with a high emittance densifier coating.

Abstract: A diffuse reflector is provided which isotropically reflects the infrared and far-infrared regions of the spectrum. The reflector includes a metal plate having one surface that is roughened by an electric discharge machine so as to have an r.m.s. roughness large enough to diffusely reflect far-infrared radiation. The roughening process creates facets having cavities which trap and diffusely reflect normally incident far-infrared radiation. An example of a reflector so produced has an isotropic bidirectional reflectance distribution function approximately equal to 1/.pi. sr.sup.-1 between the wavelengths of 5 .mu.m and 100 .mu.m.

Abstract: A low-density resin impregnated ceramic article advantageously employed as a structural ceramic ablator comprising a fired preform of ceramic fibers. The fibers of the ceramic preform are coated with an organic resin film. The organic resin can be a thermoplastic resin or a cured thermosetting resin. In one embodiment, the resin is uniformly distributed within the ceramic article. In a second embodiment, the resin is distributed so as to provide a density gradient along at least one direction of the ceramic article. The resin impregnated ceramic article is prepared by providing a fired preform of ceramic fibers; immersing the preform of ceramic fibers in a solution of a solvent and an organic resin infiltrant; and removing the solvent to form a resin film on the ceramic fibers.

Abstract: An ice detector and deicing fluid effectiveness monitoring system for an aircraft is disclosed. The ice detection portion is particularly suited for use in flight to notify the flight crew of an accumulation of ice on an aircraft lifting and control surfaces, or helicopter rotors, whereas the deicing fluid effectiveness monitoring portion is particularly suited for use on the ground to notify the flight crew of the possible loss of the effectiveness of the deicing fluid. The ice detection portion comprises a temperature sensor and a parallel arrangement of electrodes whose coefficient of coupling is indicative of the formation of the ice, as well as the thickness of the formed ice. The fluid effectiveness monitoring portion comprises a temperature sensor and an ionic-conduction cell array that measures the conductivity of the deicing fluid which is indicative of its concentration and, thus, its freezing point.

Abstract: A retroreflective type focusing schlieren system which permits the light source to be positioned on the optic side of the system. The system includes an extended light source, as opposed to a point source, located adjacent a beam splitter which projects light through the flow field onto a reflecting grating in the form of a grid which generates sheets of light that are directed back through the flow field and the beam splitter onto a primary lens behind which is located a cut-off grid having a grid pattern which corresponds to the grid pattern of the reflecting grating. The cut-off grid is adjustably positioned behind the primary lens and an image plane for imaging the turbulence is adjustably located behind the cut-off grid.

Abstract: An acoustic sensor for measuring acoustic waves contained in fluid flow flowing over the sensor. The acoustic sensor reduces any unwanted self-noise associated with the flowing fluid by providing a nose cone having proper aerodynamic properties and by positioning the diaphragm of a microphone of the sensor at a location where any unwanted noise is at a relatively low level. The nose cone has a rounded, blunt or even sharp tip neither of which creates any major disturbances in the flowing fluid which it intercepts.

Abstract: A method and apparatus for passing light bundles through a multiple pass sampling cell. The multiple pass sampling cell includes a sampling chamber having first and second ends positioned along a longitudinal axis of the sampling cell. The sampling cell further includes an entrance opening, located adjacent the first end of the sampling cell at a first azimuthal angular position. The entrance opening permits a light bundle to pass into the sampling cell. The sampling cell also includes an exit opening at a second azimuthal angular position. The light exit permits a light bundle to pass out of the sampling cell after the light bundle has followed a predetermined path.

Abstract: Sewn, quilted ceramic blankets (AFRSI) and integrally woven core insulation systems (TABI) were examined in a 170 decibel aeroacoustic environment under oscillating air loads. Preconditioning in a radiant heat source was done at both 2000.degree. F. and 2500.degree. F. before testing. A multi-layer ceramic weave construction based on an angle interlock weave architecture is superior over all other TPS systems examined. These configurations do not require a surface coating to enhance survivability. Single-ply TABI fabric surfaces using an insulated integrally woven core structure survive up to 2000.degree. F. without the use of a ceramic coating to toughen the surface to the aeroacoustic noise level. AFRSI blankets of the art require a ceramic coating in order to demonstrate comparable performance after exposure to a 2000.degree. F. radiant heat temperature.

Abstract: A novel rehydration beverage containing sodium chloride, sodium citrate and aspartame useful for rapid restoration of hydration homeostasis. The beverage is particularly useful for restoration of normal body fluid volumes and their intracellular and extracellular distribution during a hypohydration state observed in astronauts and air passengers.

Abstract: Synthetic head related transfer functions (HRTFs) for imposing reprogrammable spatial cues to a plurality of audio input signals included, for example, in multiple narrow-band audio communications signals received simultaneously are generated and stored in interchangeable programmable read only memories (PROMs) which store both head related transfer function impulse response data and source positional information for a plurality of desired virtual source locations. The analog inputs of the audio signals are filtered and converted to digital signals from which synthetic head related transfer functions are generated in the form of linear phase finite impulse response filters. The outputs of the impulse response filters are subsequently reconverted to analog signals, filtered, mixed and fed to a pair of headphones.

Abstract: Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful to provide lightweight thermal insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

Abstract: A new highly crosslinked silicone polymer particle for gas chromatography application and a process for synthesizing such copolymer. The new copolymer comprises vinyltriethoxysilane and octadecyltrichlorosilane. The copolymer has a high degree of crosslinking and a cool balance of polar to nonpolar sites in the porous silicon polymer assuring fast separation of compounds of variable polarity.

Abstract: A maneuver envelope warning system for an aircraft having operating limits, operating condition sensors and an indicator driver. The indicator driver has a plurality of visual indicators. The indicator driver determines a relationship between sensed operating conditions and the operating limits; such as, a ratio therebetween. The indicator driver illuminates a number of the indicators in proportion to the determined relationship. The position of the indicators illuminated represents to a pilot in an easily ascertainable manner whether the operational conditions are approaching operational limits of the aircraft, and the degree to which operational conditions lie within or exceed operational limits.

Abstract: In rocket engines power is usually obtained by burning fuel and oxidizer. The two are mixed, pressurized, and directed to a combustion chamber by means of turbopumps. Hydrostatic bearings have been proposed for use in these turbopumps because during flight, hydrostatic lubrication can reduce roller bearing wear. But during startup, acceleration and shutdown high pressure fluids are not available to provide fluid lubrication for hydrostatic bearings. During these periods a second bearing is required to carry the load, rendering hybrid bearings desirable for rocket engine turbopumps. Herein a hybrid hydrostatic-rolling element bearing has been provided. The rolling element bearing is locked on a stationary housing through which a rotating journal passes. A transient supporting ring is keyed to the journal. It is adapted to lock on the rolling element bearing so that the rolling element bearing supports radial loads during startup, initial acceleration, deceleration and shut down, and to release at high speeds.

Abstract: A slip joint connector for joining first and second structural elements together. The connector has a first body member attachable to the first structural element and a second body member attachable to the second structural element. The first body member has a male protuberance including a conical portion and the second body member has a conical receptacle for cooperatively receiving the conical portion of the protuberance. The protuberance includes a bridging portion for spacing the conical portion from the remainder of the first body member and the second body member has a well communicating with the conical receptacle for receiving the bridging portion. The conical male portion internally carries a nut while the second body member may receive a bolt through the receptacle to be threadedly received by the nut to secure the first and second body members tightly together.

Abstract: A method and system for performing pattern analysis with a neural network coarse-code a pattern to be analyzed so as to form a plurality of sub-patterns collectively defined by data. Each of the sub-patterns comprises sets of sub-pattern data. The neural network includes a plurality of fields, each field being associated with one of the sub-patterns so as to receive the sub-pattern data therefrom. Training and testing by the neural network then proceeds in the usual way, with one modification: the transfer function thresholds the value obtained from summing the weighted products of each field over all sub-patterns associated with each pattern being analyzed by the system.