Briefs : Physical Sciences
Miniature Electron Microscopes Without Vacuum Pumps

The proposed electron microscope would function without the need for external vacuum pumps and thus have a significant reduction in size, mass, and power consumption, as compared to conventional (vacuum-pump-equipped) electron microscopes now used in many laboratories. These devices could be...

Briefs : Mechanical & Fluid Systems
Subliming Solid Microthrusters

Devices are proposed that would sublime solid propellants to generate small thrusts for maneuvering spacecraft with masses of no more than 15 kg. With solids rather than gases in propellant tanks, there would be no leakage and thus no waste of limited quantities of propellants. There would also be none of the...

Briefs : Materials
LaNi₅₋ₓSnₓ Electrodes for Ni/MH Electrochemical Cells

Experiments have shown that improved hydride-forming negative electrodes for rechargeable nickel/metal hydride (Ni/MH) electrochemical cells can be made by substituting Sn for some of the Ni in LaNi5. Since the year 1988, it has been known that partial substitution of Sn...

Briefs : Mechanical & Fluid Systems
Trefoil Rotary Flexure

The figure illustrates a device that flexes to allow rotation about a single axis through a total range of ±12°. This device was designed to offer the following advantages over commercial flexural pivots:

Briefs : Robotics, Automation & Control
Jewellike Bearings for Blood Pumps

Jewellike bearings have been devised to enhance the performance and safety of small rotary pumps that are used to increase or sustain flows of blood in cardiac patients. A pump of this type includes a spinning impeller in an axial- or radial-flow configuration. The impeller shaft is supported at its ends by...

Briefs : Photonics/Optics
Fiber Laser Amplifiers with Broad Applications

The Boeing Company has developed fiber-laser-amplifier technology representing the latest in diode-laser-pumped systems, providing high output power, high brightness, tunability, frequency-doubled output, multi-wavelength amplification, and narrow linewidth operation. The technology is a proven...

Briefs : Electronics & Computers
TRL Fixture for Cryogenic Testing of Microwave Components

A single-block fixture enables the rapid and accurate electrical characterization of planar microwave electronic components, by use of the through-reflect-line (TRL) technique, in air or in a vacuum at any temperature from ambient down to cryogenic temperatures. Heretofore, the TRL...

Briefs : Physical Sciences
Easy-to-Use High-Temperature Strain-Sensor Systems

Easy-to-use high-temperature strain-sensor systems based on strain gauges made from Pd/Cr-alloy wires have been developed. These systems include strain-gauge units comprising Pd/Cr wires bonded to high-temperature metal-alloy shims by flame spraying of ceramic materials. Optionally, a...

Briefs : Materials
Improved Bond-Coat Layers for Thermal-Barrier Coatings

Current production thermal-barrier coatings (TBCs) have been shown to be capable of reducing the average temperatures of metallic components by 50 to 80 °C and hot-spot temperature by up to 140 °C. This substantial temperature reduction has been used to extend the life of metallic...

Briefs : Electronics & Computers
Stable Breakdown Obtained in Silicon Carbide Rectifiers

Experiments have revealed that stable breakdown-voltage characteristics can be achieved in silicon carbide rectifiers. Stable breakdown-voltage characteristics are essential to the ability to withstand overvoltage transients and are therefore necessary for reliability in high-power...

Briefs : Photonics/Optics
Semimonolithic Cavities for Optical Frequency Conversion

Semimonolithic resonant structures external to lasers have been proposed for use in optical frequency-conversion applications - for example, doubling the frequencies of laser beams. These structures would offer most of the advantages, without most of the disadvantages, of monolithic...

Briefs : Materials
Trading Risk Versus Cost of a Composite-Material Structure

A probabilistic method has been developed for use in designing a composite-material structure to achieve a balance between maximum reliability and minimum cost. This method accounts for all naturally occurring uncertainties in properties of constituent materials, fabrication variables,...

Briefs : Electronics & Computers
Single-Event Latchup Protection of Integrated Circuits

Many commercially available advanced-technology CMOS and bipolar integrated circuits are susceptible to single-event latchup (SEL) effects caused by heavy ions or protons from cosmic rays or solar flares, making them unsuitable for satellite applications. Remanufacturing the integrated...

Briefs : Electronics & Computers
Inverse Rectennas for Two-Way Wireless Power Transmission

The term "inverse rectenna" may seem like an oxymoron at first glance. However, preliminary experiments have demonstrated that a rectenna of suitable design can be made to operate in an inverse mode, in which radio-frequency (RF) power is generated in the rectenna rectifier circuits and...

Briefs : Mechanical & Fluid Systems
Laser Anemometer Measures Flow in a Centrifugal Compressor

Detailed measurements of complex flow fields within the NASA Low Speed Centrifugal Compressor (LSCC) have been acquired. The measurement data provide insight into the fundamental physics of flow in centrifugal compressors, and can be used to assess computational fluid dynamics codes and...

Briefs : Electronics & Computers
Heat Pipes for Temperature Control in Electronics

As electronic circuits become more densely packaged and higher in power, maintaining them within permissible temperature ranges becomes a major issue. This is especially true in the case of such portable devices as laptop computers, cellular telephones, and other hand-held units. Cooling by a...

Briefs : Electronics & Computers
SQUID-Based Asymmetric Planar Gradiometer

Berkeley Laboratory researchers have demonstrated a novel superconducting gradiometer that helps to reduce ambient magnetic field noise generated by relatively distant sources in favor of tiny magnetic signals generated by a local source. This is another step toward the operation of SQUID-based...

Briefs : Mechanical & Fluid Systems
Emergency-Shutoff Valves Would Be Triggered by Accelerations

Automatic valves have been proposed for shutting off flows of liquids when abnormally large accelerations occur. These valves could be used, for example, to prevent outflows of flammable, valuable, or toxic liquids from pipelines that have been struck by vehicles or that have become...

Briefs : Robotics, Automation & Control
Lightweight "Beach-Ball" Robotic Vehicles

Lightweight, inflatable robotic vehicles (rovers) that superficially resemble beach balls and that could be driven by wind and/or electric power are undergoing development. These rovers were conceived for carrying scientific instruments across rocky terrain on Mars, and are intended to move faster,...

Briefs : Electronics & Computers
GPS Drives Interactive Map Showing Position of Test Airplane

An electronic system that comprises airborne and ground-based subsystems generates data for a global real-time interactive map (GRIM) that displays the current position and velocity of the NASA F-18 Systems Research Aircraft (SRA). This system utilizes the Global Positioning System...

Briefs : Mechanical & Fluid Systems
Software for Navigation of a Spacecraft Flying in Formation

The Spacecraft Autonomous Navigation System using GPS for Earth Orbiters (SANS-GEO) computer program is designed to perform the navigation calculations that will enable the New Millennium Program's Earth Orbiter-1 (EO-1) spacecraft to fly in formation with the Landsat-7 (LS-7)...

Briefs : Electronics & Computers
Training Neural Networks With Fewer Quantization Bits

A method for reducing the number of bits of quantization of synaptic weights during training of an artificial neural network involves the use of the cascade back-propagation learning algorithm. The development of neural networks of adequate synaptic-weight resolution in very-large-scale...

Briefs : Mechanical & Fluid Systems
Program Performs High-Precision Spacecraft-Constellation Navigation

The Multiple Interferometric Ranging Analysis using GPS Ensemble (MIRAGE) computer program processes spacecraft-tracking data to determine orbits of single satellites, or of multiple satellites with intersatellite tracking, to within position errors as small as a few...

Briefs : Electronics & Computers
Terrestrial Portable Spacecraft-Mission-Support Stations

A data-communication and -processing network of compact, laptop-computer-based portable stations communicating via the World Wide Web (WWW) has been proposed as a relatively inexpensive end-to-end ground support system for future spacecraft missions. At present, end-to-end ground support...

Briefs : Mechanical & Fluid Systems
Finite-Element Model of Piezoelectric and Thermal Effects

A mathematical model that includes layerwise finite elements has been developed for use in numerical simulation of the coupled electrical, mechanical, and thermal responses of composite plate structures that incorporate piezoelectric sensors and actuators. Typically, the sensors and...

Briefs : Mechanical & Fluid Systems
Passive Capture Joint WithThree Degrees of Freedom

A new joint, proposed for use on an attachable debris shield for the International Space Station Service Module, has potential for commercial use in situations where hardware must be assembled and disassembled on a regular basis.

Briefs : Physical Sciences
Automatic Thermal Switches With No Moving Parts

Quasi-thermostatic gas-gap thermal switches have been proposed. These switches would operate automatically, would contain no moving parts, would not require power supplies or controls, would not consume any materials, and would not create vibrations. The operation of a switch of this type would be...

Briefs : Robotics, Automation & Control
Simulations in Support of Towed Flight Demonstration

The Eclipse flight project was established to demonstrate a reusable-launch-vehicle concept developed by Kelly Space and Technology, Inc. An F-106 delta-wing aircraft was chosen as the towed vehicle, and a C-141A transport-type airplane was selected for the towing vehicle. These airplanes are...

Briefs : Electronics & Computers
Improved Two-Wavelength Focal-Plane Array of QWIPs

A focal-plane array (FPA) of GaAs-based quantum-well infrared photodetectors (QWIPs) that would detect images in two wavelength bands simultaneously is undergoing development. From ratios between image intensities at the two wavelengths, one can calculate the temperatures of imaged objects by...

Briefs : Materials
Software for Probabilistic Analysis of Composite Structures

GENOA is an advanced, completely integrated, hierarchical software package for computationally simulating the thermal and mechanical responses of high-temperature composite materials and of structures made of those materials. The development of GENOA was guided partly by the need for a...

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