August 1998

Briefs: Mechanical & Fluid Systems
Updated Program for Computing Stresses in Spur Gears

DANST-PC is version 3.01 of a computer program for analysis of the statics and dynamics of spur-gear systems. ["DANST" signifies "Dynamic Analysis of Spur Gear Transmissions." A previous version was described in "Computing Stresses in Spur Gears," NASA Tech Briefs, Vol. 19, No. 12 (December...

A microwave-heating technique provides for batch processing of multiple, identically sized and shaped samples of the same material. The technique involves (1) excitation of a symmetrical...

The Viewing Imager/Gimballed Instrumentation Laboratory and Analog Neural Three-Dimensional Processing Experiment (VIGILANTE) is a "smart" optoelectronic sensor system that...

Briefs: Robotics, Automation & Control
Doped ZnTe: a Developmental Photorefractive Material

Zinc telluride is a semiconductive material that has been found to become photorefractive when it is suitably doped with vanadium or with manganese and vanadium. The combination of...

Rapid technological progress, especially in computers, CCD technology, color printers and scanners makes forgery and counterfeit of identification documents such as credit cards, or...

Briefs: Robotics, Automation & Control
Snakelike Robots Would Maneuver in Tight Spaces

Robots with multiple-link arms that could reach through narrow openings into hidden cavities are undergoing development. Called "multifunction dexterous boro-robots" (MDBRs), these robots...

Briefs: Robotics, Automation & Control
Wavy Blades for Secondary Centrifugal Blood-Pump Impeller

The rectangular-cross-section blades of a centrifugal secondary impeller in a ventricular-assist blood pump would be replaced with blades of wavy cross section, according to a proposal. As explained below, the resulting modification in the flow pattern would reduce the tendency toward...

A laser Doppler velocimeter (LDV) system has been developed for use on practical gas-turbine engines. The system has been used to measure inlet and exhaust velocities on an F-100 EMD...

Coherent gradient sensing (CGS) is a diffraction-based, noncontact optical technique for measuring the slight curvature of a nearly flat thin film or specimen surface. CGS is especially...

Briefs: Electronics & Computers
Self-Checking Circuitry for Detecting Single-Event Latchups

High-performance electronic circuits would incorporate self-checking features for detection of radiation-induced single-event latchups (SELs), according to a proposal. The basic SEL-detection scheme calls for redundant circuitry and a current-voting scheme similar to voting schemes...

Experiments have shown that improved hydride-forming negative electrodes for rechargeable nickel/metal hydride (Ni/MH) electrochemical cells can be made by substituting Ge for...

Voltage-tunable optical band-pass filters based on surface plasmon waves have been proposed. These filters would function at both visible and infrared wavelengths. Whereas...

A process for the growth of single-crystal (epitaxial) multilayer films has been developed at the Naval Surface Warfare Center, Dahlgren Division. This process is predicated on the preparation of a...

Briefs: Physical Sciences
Miniature Microscope Without Lenses

In a proposed optical microscope, the focusing optics of a conventional microscope would be supplanted by a combination of a microchannel filter and an advanced electronic image sensor. Elimination of focusing optics would eliminate the need for the time-consuming focusing operation, making it possible to...

Briefs: Manufacturing & Prototyping
Methods of Manufacturing Fiber Optic Components

The methods described are used with existing fiber optic technologies, and are based on several patents and on disclosures now before the U.S. Patent and Trademark Office. The patents are No....

Briefs: Physical Sciences
Microlenses for Calibrating Phase Doppler Particle Analyzers

Simple optical devices called "scattering reticles" have been invented for calibrating Phase Doppler Particle Analyzers (PDPAs), which are optical instruments that analyze scattered light to determine the sizes and velocities of droplets. A scattering reticle comprises a polymeric...

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...

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...

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...

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...

The Boeing Company has developed fiber-laser-amplifier technology representing the latest in diode-laser-pumped systems, providing high output power, high brightness, tunability,...

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...

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...

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...

Experiments have revealed that stable breakdown-voltage characteristics can be achieved in silicon carbide rectifiers. Stable breakdown-voltage characteristics are essential to the...

Semimonolithic resonant structures external to lasers have been proposed for use in optical frequency-conversion applications - for example, doubling the frequencies of laser beams....

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...

A simple technique for extending the dynamic range of a charge-coupled-device (CCD) video camera involves the use of photochromic material — the same material used in...

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