Abstract: A repetitively pulsed chemical oxygen-iodine laser having a resonant cavity containing a lasing medium in the form of a flowing mixture of excited oxygen and iodine atoms and an iodine absorption region within the resonant cavity. The iodine absorption region includes a source of iodine atoms and a magnetic field associated therewith. Selectively altering the magnetic field results in changing the absorption characteristics of the iodine atoms and therefore effectively pulses the output of the laser.

Abstract: A high power, closed cycle photolytic atomic iodine laser system having a high molecular weight gas as a laser fuel and which requires a high velocity flow of the laser fuel, the laser fuel to be in a selected low pressure range, and the laser fuel to be of very high purity. The laser system has a turbo-molecular blower for circulating the laser fuel. The turbo-molecular blower provides the high velocity flow, the selected low pressure through the laser gain cell, and a high compression ratio. The velocity is in a range of about 1 m/s to 100 m/s, the compression ratio being in a range from about 10:1 to 1000:1, the selected low pressure in a range of about 5 to 60 Torr, and the turbo-molecular blower not contaminating the laser fuel of the closed cycle fuel system by the use of ferrofluidic rotary seals. The turbo-molecular blower has a blower assembly that provides a continuous, high velocity and pressurized gas flow.

Abstract: A multilayer stack of alternating low index and high index of refraction low loss dielectric mirror layers are formed on top of a metallic mirror surface, the thicknesses of the mirror layers being chosen to satisfy the Bragg condition at a selected incident angle of polarized light. The dielectric layer adjacent the metallic reflective mirror substrate can have a thickness which produces circularly polarized light exiting the apparatus. An electro-optical layer of EO material can be substituted for the dielectric layer adjacent the metallic mirror and a controlled elliptically polarized output can be produced by altering the electric field applied across the EO layer. This device can be used as a very high power high speed EO modulator.

Abstract: The invention provides method and apparatus for chemical milling of a metal part in a milling solution that reduces hydrogen absorption by the part wherein, the metal part to be milled, which serves as the anode, and a cathode of more noble metal than the anode, are mounted in such solution. Unlike the prior art, the cathode and anode are separated in such solution but electrically connected by a conductor therebetween, which conductor is insulated from the milling solution. Thus anode and cathode are mounted, spaced apart in the milling solution, so that metal dissolves from the anode surface, milling such part while electrons flow from anode to cathode by said conductor so that hydrogen forms at the cathode, removed from the anode part, to reduce hydrogen absorption by such part.The anode part can be of, eg. titanium and the cathode of a more noble metal, eg. platinum, which serves to draw the hydrogen to the cathode and away from the anode part, preventing or reducing absorption of hydrogen into, eg.

Abstract: Twin-free (100) InP crystals of large dimensions and having flat crowns are produced by combining the magnetic liquid encapsulated Kyropoulos (MLEK) process and the magnetic liquid encapsulated Czochralski (MLEC) process. Observation of the flat crown by high intensity light ensures twin-free growth in the magnetic environment.

Abstract: The magnetoelectric coefficient in iron-based alloys has a stress value of about 0.6 of that of the elastic limit. A reversal in sign is caused by structural phase slip which is the basis for the onset of metal fatigue. Based on this phenomenon, a method is provided for determining the onset of metal fatigue. The method includes applying a periodic mechanical stimulus at a given frequency to a test structure, and using a magnetometer, sensing the magnetic field of said structural element during the application of stimulus, and then determining whether or not there is a 180 degree difference between the phase of the stimulus and that of the magnetic response for various regions of the test structure.

Abstract: The invention provides a low friction gas seal between moving and stationary parts in the exhaust nozzle of a gas turbine engine. Such seal is in the form of a roller mounted on a pair of pivot arms to the movable member, which roller rides on the stationary part in sealing engagement therewith. The roller is preferably mounted behind a heat shield in rubbing (and sealing) engagement therewith. The roller has an outer tube of soft ceramic fabric for high temperature resistance and good sealing attributes. Such roller seal provides good sealing, e.g. between a convergent or divergent flap edge and the adjacent wall of an engine exhaust nozzle or between other moving and stationary parts.

Abstract: A method for fabricating a hybrid MQW spatial light modulator is described which comprises steps of depositing on a substrate in sequence a first layer to preselected thickness of n+ (or p+) semiconductor material, a second layer to preselected thickness of intrinsic semiconductor material and a third layer to preselected thickness of p+ (or n+) semiconductor material to form a modulator portion, applying a metallic layer defining a mirrored surface to the third layer of the modulator portion, providing a prefabricated silicon PIN detector having a layered structure including an intrinsic layer of preselected thickness sandwiched between an n+ layer and p+ layer of respective preselected thicknesses and joining the PIN detector to the mirrored surface using a conductive adhesive layer, selectively boring channels into the modulator portion to preselected depth into the PIN detector to form an array of a plurality of pixels on the modulator portion, filling the channels with light blocking material, and applyi

Abstract: A flexible coupling is provided for two relatively movable pipes, which coupling hasa) a bellows tube having transversely corrugated sidewalls which bellows terminates in two rounded nozzles, which nozzles insert into connecting pipes, (e.g. in the air bypass duct of a gas turbine engine) andb) means to seal each nozzle in each respective pipe such that upon relative axial and lateral displacement between connecting pipes, the bellows tube flexes to maintain the sealed juncture between it and the connecting pipes.

Abstract: The space debris clearing device of the invention, following launch and placement in or near an orbit considered to be highly populated with debris, is intended to clear the debris allowing safe paths and orbits for space assets. The device is made of a castable, energetic material, and shaped to meet specific clearing requirements. Once in position the device is remotely detonated, and an impulse, caused by the expanding detonation products, is imparted to the debris, pushing the debris into a reentry or earth escape trajectory.

Abstract: A ring laser gyro, RLG, is a highly accurate optical rotation sensor using counter propagating light beams to sense rotation as a rate integrating gyro. There is however, the problem of RLG blindness or loss of output data during high energy radiation, which frequently incapacitates the data-sending abilities of conventional photodetectors, mounted on RLG output prisms. This temporary RLG blindness during the high energy pulse is followed by a more permanent performance degradation, including photo darkening of the conventional RLG photodiodes which typically contain crystalline silicon or other crystalline components, which are degraded by high energy radiation, as noted above. The present invention is believed to solve this problem by providing photodetectors of amorphous material, e.g. a-Si:H PIN diode structures, which are vapor deposited onto the face of an RLG output prism.

Abstract: A method is disclosed for determining bulk modulus of a liquid based on a pressure-volume-temperature relationship at constant volume corrected for changes in system volume due to elevated pressure and temperature. The apparatus used to determine bulk modulus comprises a pressure vessel in which the liquid to be tested is introduced, and from which all gases are removed. The vessel is placed in a constant temperature oven and the pressure is recorded. The method for determining bulk modulus and density requires calibration of the vessel volume changs due to pressure and temperature.

Abstract: A system for digital conferencing over narrowband channels which allows use by multiple simultaneous speakers and which allow for interfacing between vocoders which operate at different bit rates. The system takes advantage of the properties of multi-rate parametric vocoders (which includes the Sinusoidal Transform Coder and the Multi-Band Excitation Vocoder, as well as embedded coders), defined as parametric vocoders for whom the basic model and parameter set remain unchanged over a wide range of bit-rates. The system performs signal summation. To maintain quality for a single speaker while allowing multiple speakers, the system adaptively allocates channel bandwidth based on the number of speakers to be represented. This system also provides digital-to-digital conversion between narrow-band digitizers (vocoders) operating at different bit-rates.

Abstract: A superconducting switch is composed of anisotropic magnetic material. The switch has a first superconducting section, a variable resistive section and a second superconducting section. An external magnetic field is applied so that the first and second superconducting sections remain superconducting and the resistive section changes resistance when the magnetic field applied exceeds the critical field of the variable resistance section. The different critical field regions are achieved by exploiting the natural critical field anisotropy of the ceramic superconductors (a previously unobserved phenomena in metal superconductors). By making the different sections with different orientations they will exhibit different critical field valves for a given direction of applied fields. The state of the switch is changed by either increasing or decreasing the external magnetic field about the critical field value of the resistive section of the switch.

Abstract: A three-level atomic system in a resonance Raman configuration is provided, and self-pumped optical phase conjugation is performed in which the pumps are self-induced as standing waves in a Raman laser. Self-pumped reflectivities approaching five percent are obtained for input intensities of 20 watts per square cm. This low optical input intensity combined with predicted submicrosecond response times indicates that the resonant Raman interaction may provide the basis for a promising new class of non-linear optical materials.

Abstract: A Mono-Blade Antenna is disclosed which operates over many octaves of bandwidth. Electromagnetic waveforms may be transmitted and received with multi-decade bandwidth using: a metal ground plane, a Mono-Blade Antenna element fixed above the ground plane, and a coaxial transmission line feed which is connected to the antenna element and the ground plane. The antenna element has three sections: a throat, a mouth, and a radial tip. The throat is comparatively narrow and serves as the element feed point by being connected to the center conductor of the coaxial cable. The mouth is the mid-section of the antenna element, which is the widest section of the blade. The tip of the blade is formed by an arc of approximately constant radius, which results in a low voltage standing wave ratio.

Abstract: A device for forcing fluid along a collapsible conduit is described which comprises a yoke including a web and first and second projecting leg members, a first roller supported between the first and second leg members for rotation about a first axis, a block member supporting an axle and a second roller for rotation about a second axis substantially parallel to the first axis, the second leg member and block member each having one or more holes therethrough for receiving bolts connecting the block and second leg member, a spring interconnecting each bolt and the second leg member for resiliently holding the block member and second roller in a substantially parallel juxtaposed position near the second leg member and the first roller, overcenter locking means interconnecting the second leg member and block member for selectively locking the block and second roller into resilient engagement with the second leg member and first roller with a collapsible conduit disposed between the first and second rollers, and a

Abstract: A thermal control system for a space body uses an active control means to prevent laser beam radiation damage to a heat radiator. A conventional louver and louver actuator are coupled to an active overdrive actuator that closes the louver when hostile laser radiation is present. An extended bimetallic coil spring with a heater therein rotates opposite to the louver actuator in an increasing temperature environment. A cam of the overdrive actuator engages a louver arm when hostile laser radiation is present, otherwise, the louver can move freely within the cam.

Abstract: A multi-octave bandwidth antenna is disclosed which radiates with variable polarizations using: a metal ground plane, first and second blade antenna elements, first and second coaxial transmission line feeds, and a 180.degree. hybrid coupler. The two blade antenna elements are fixed above the metal ground plane in proximity with each other, and fed respectively by the central conductors of the first and second coaxial transmission line feeds. The 180.degree. hybrid coupler has a sum and difference port to control the polarization of waveforms of the antenna.

Abstract: A Bi-Blade Antenna is disclosed which will radiate and receive multi-octave electromagnetic waveforms with century bandwidth (i.e. 100 to 1) using two blade antenna elements and a coaxial transmission line feed. The blade antenna elements each have a comparatively narrow throat, a mid-section called a mouth, and a tip. The two throats are fixed in proximity to each other and are fed by the coaxial line feed. The central conductor of the feed is connected to one throat while the outer coaxial conductor is connected to the second throat. The mouth is formed by an arc of constant radius to result in a low voltage standing wave ratio of about 1.19 to 1.