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Briefs: Materials
Plasma CVD of Boron Carbide by Pulsed Secondary Discharge
An improved method of plasma chemical-vapor deposition (CVD) of a thin film of boron carbide has been devised. Boron carbide is useful because it is hard, is electrically insulating, withstands high temperature, and resists chemical attack. Plasma CVD of boron carbide involves the thermal...
Briefs: Mechanical & Fluid Systems
Magnetic Couplings for Gas-Driven Catapults
A proposed magnetic-coupling scheme would afford additional degrees of freedom to optimize the designs of gas-driven catapults or launchers. The scheme could be applied to gas guns in diverse applications, including launching spacecraft or aircraft, propelling various objects at high speeds along the...
Briefs: Mechanical & Fluid Systems
A relief valve has been designed to limit the differential pressure between two fluids that are not allowed to be mixed. This valve offers advantages over both simple check valves and simple relief valves. A...
Briefs: Mechanical & Fluid Systems
Vortex-Fired Liquid-Fuel Rocket Combustion Chambers
Liquid-fuel rocket engines that utilize vortex flow fields to keep combustion-chamber walls cool have been investigated in computational simulations and experiments. In an engine of this type, the vortex flow establishes radial gradients of pressure and density that cause the lower-density hot...
Briefs: Mechanical & Fluid Systems
Systems for Dynamic Control of Growth of Protein Crystals
Computer-controlled laboratory apparatuses for real-time monitoring and control of the growth of protein crystals are undergoing development. By use of an apparatus of this type, one can monitor and control several parameters that affect the growth of protein crystals; these parameters...
Briefs: Medical
In a new method of delivering drugs to target sites in a human body, (1) the drugs would be stored in inactive forms in timed-release microcapsules that would be injected, then (2) the drugs would...
Briefs: Physical Sciences
Spaceborne Telescope for Communication, Ranging, and Imaging
A report describes a program to develop a multi-function telescope to be carried aboard spacecraft of the planned X2000 series of planetary missions. [A related multi-function telescope was described in "Telescope for Imaging and Laser Communication" (NPO-20388), NASA Tech Briefs,...
Briefs: Physical Sciences
Dislocation-Induced Changes in InxGa1 -xAs Quantum Dots
A report describes an experimental investigation that revealed a previously unknown type of spatial alignment of quantum dots (QDs) in InxGa1 -xAs/GaAs multilayer structures. Multilayer arrays of QDs (in the form of nanometer-sized InxGa1-xAs islands) were formed by alternately depositing...
Briefs: Physical Sciences
Solitons on WDM Beams in a Nonlinear Optical Fiber
This paper sets the ultimate limit on the maximum amount of optical data pulses that can be sent through a single fiber in a given period under the wavelength-division-multiplexed (WDM) format. The discovery in 1973 that optical soliton on a single wavelength beam can exist in fiber is one of...
Briefs: Information Technology
Fast Observers for Spacecraft Pointing Control
A report discusses the design of fast stochastic observers for spacecraft pointing control. In this special context, "observers" signifies mathematical algorithms, implemented on computers aboard spacecraft, through which one processes sensory data (principally, the outputs of star trackers and...
Briefs: Materials
Nesting-Hoop Solar Sail
A report discusses a proposed nesting-hoop solar sail that would be used to propel a spacecraft on a deep-space mission. The nesting-hoop design concept was chosen as one that would afford a desired combination of small mass and compact stowage during launch. The sail would include multiple disks, each comprising a thin...
Briefs: Electronics & Computers
The Parallel Integrated Frame Synchronizer (PIFS) chip is one of three very-large-scale integrated (VLSI) circuits designed for ground processing of streams of telemetric data received from...
Briefs: Electronics & Computers
An advanced complementary metal oxide/semiconductor (CMOS) active-pixel sensor (APS) incorporates integrated circuitry that computes the centroid of the image in a window selectable by the...
Briefs: Manufacturing & Prototyping
Software for Designing Plasma Reactors for Microelectronics
Outer-space plasmas and arc-jet plasmas are well known to many researchers at NASA. Efforts to understand the structures of these plasmas have consumed years of research at various NASA laboratories. Computational modeling of such plasmas involves analyses of multicomponent,...
Briefs: Manufacturing & Prototyping
Writing Circuit Patterns by Use of Scanning UV Lasers
Scanning ultraviolet (UV) lasers would be used to expose ultraviolet-sensitive photoresists to form patterns of conductors for electronic circuits, according to a proposal. Heretofore, such patterns have been formed by exposing photoresists to collimated ultraviolet or visible light through...
Briefs: Mechanical & Fluid Systems
A Rankine-cycle engine that contains a binary working fluid (ammonia + water) and a recuperative heat exchanger has been built and tested. This engine is a prototype of "bottoming"-cycle...
Briefs: Photonics/Optics
A technique of parallel-beam interferometry with spatially incoherent light has been proposed to solve two problems that arise in conjunction with using interferometry to measure the shape of...
Briefs: Photonics/Optics
A method of correcting for the distorting effects of the atmosphere upon a laser beam used in free-space optical communication has been proposed. The original version of the method...
Briefs: Photonics/Optics
Improved Optical Fallout Monitor
Modifications have been made to upgrade the system described in "Optoelectronic Particle-Fallout Sensor" (KSC-11687), NASA Tech Briefs, Vol. 19, No. 4 (April 1995), page 17a. A description of the unmodified version of the system is necessary to place a description of the modifications in context:
Briefs: Photonics/Optics
In a proposed method for rapidly detecting hydrazine in air at concentrations at or above 10 parts per billion by volume (ppbv), tunable diode lasers (TDLs) and photodetectors would be used...
Briefs: Photonics/Optics
A proposed electro-optical apparatus would shift the frequency of a laser beam by a controllable amount within the range of about ±10 GHz. It would be a wide-band alternative to an acousto-optical tunable...
Briefs: Photonics/Optics
Plasma spraying has been shown to be an effective means of depositing thin films of various oxides for use as wavelength-selective emitters for thermophotovoltaic devices (see Figure...
Briefs: Electronics & Computers
A class of developmental asymmetric electrochemical capacitors is based on (1) nonpolarizing positive electrode made of nanotructured γ-MnO2, (2) aqueous electrolyte , and (3)...
Briefs: Physical Sciences
The Atmospheric Electron X-ray Spectrometer (AEXS) is being developed for performing rapid, nondestructive in situ analyses of the elemental composition of surfaces. The capability of the AEXS to operate...
Briefs: Electronics & Computers
Locally Connected Neural Networks for Pattern Recognition
Neural networks of a proposed type would be formed with computational units called "neuromorphs" attached in a locally connected array. These neural networks would achieve pattern recognition invariant under rotation and translation by exploiting a combination of network symmetry and...
Briefs: Electronics & Computers
Cross-Correlated Trellis-Coded Quadrature Modulation
Cross-correlated trellis-coded quadrature modulation (XTCQM) has been proposed as a generic scheme with specific embodiments that potentially offer superior alternatives to other highly power- and bandwidth-efficient phase-shift-keying (PSK) modulation schemes. Examples of such schemes include...
Briefs: Test & Measurement
The development of miniature, cold- gas thrusters for on-orbit propulsion of such small devices as remotely piloted cameras and for inclusion in astronaut propulsion backpacks gave rise to a need to measure...
Briefs: Test & Measurement
Software for Designing Model Rockets for Base-Heating Tests
The Impulse Combustion Excel (ICE) computer program was developed to facilitate and accelerate the design and analysis of subscale rocket engines for use in base-heating tests. Such tests are performed on the ground to obtain data for estimating the heating effects of hot exhaust plumes on...
Briefs: Software
Software for Analysis of Contamination of the ISS
The NASAN computer program can perform detailed analyses of molecular column density and molecular deposition on and around such complex space structures as the International Space Station (ISS). Contamination from both point sources (e.g., thrusters and vents) and diffuse sources (e.g., reflected...
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