June 2000

Stories

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Briefs: Test & Measurement
A lightweight, low-power-consumption power supply has been developed to generate a combination of radio-frequency (RF) and dc voltages needed for the operation of a miniature quadrupole...
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Briefs: Electronics & Computers
Innovative optoelectronic encoders for measuring absolute, linear or angular position with super-high resolution have been invented. The new encoders rely on a combination of high-accuracy...
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Briefs: Motion Control
The figure illustrates an improved electronic circuit that generates a signal proportional to either the instantaneous vibrational velocity or the instantaneous position (equivalently,...
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Briefs: Electronics & Computers
Carbon Nanotubes as Anodes in Rechargeable Lithium-Ion Cells
Carbon nanotubes (also known as "bucky tubes") have shown promise for use as anode materials in rechargeable lithium-ion power cells. In comparison with graphite and other forms of carbon used under identical conditions, bucky tubes exhibit greater specific discharge capacity and greater...
Briefs: Motion Control
Pulse-Mode Reaction Control System Thruster
A spacecraft reaction-control-system (RCS) thruster now undergoing development generates a thrust of 870 lbf (3,870 N) by burning ethanol and liquid oxygen (LOX), which are nontoxic. The performance of the thruster has been tested in operation in multiple pulse modes with pulses as short as 160 ms; such...
Briefs: Motion Control
The figure illustrates an improved electronic circuit that excites constant-magnitude vibrations in an electrostatically actuated, capacitively sensed mechanical resonator. The circuit...
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Briefs: Motion Control
Single crystals of Tb-Dy alloys exhibit magnetostrictive strains approaching 1 percent and can generate forces sufficiently large to make them useful as actuators in cryogenic...
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Briefs: Motion Control
This is the first of four articles that address various issues concerning the generation and utilization of electronic signals in the operation of micromachined planar vibratory...
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Briefs: Electronics & Computers
Fatigue cracks and plastic deformation of parts in jet aircraft engines could be detected, even during engine operation, by use of proposed in situ monitoring devices called "wireless...
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Briefs: Motion Control
Electronic circuitry has been devised to compensate for variations in the resonance quality factor (Q) of a planar vibratory microgyroscope like that described in the first of the...
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Briefs: Physical Sciences
A computer program (see figure) has been developed to serve as a time- and cost-effective means of automating thermal analyses of such hypersonic flight systems as the space shuttle orbiter, the...
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Briefs: Physical Sciences
A computer program written within the Mathematica software system automatically generates FORTRAN computer codes that numerically simulate, with high accuracy, the acoustical physics...
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Briefs: Physical Sciences
Dryden Flight Research Center has developed a computer program that performs signal management for analysis in real time (SMART). This program, called "SMART," has been effectively used since 1991 in...
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Briefs: Mechanical & Fluid Systems
Comprehensive Micromechanics-Analysis Code (MAC/GMC)
Micromechanics Analysis Code With Generalized Method of Cells (MAC/GMC) is a comprehensive, user-friendly, efficient computer program that predicts the elastic and inelastic thermomechanical responses of continuous and discontinuous composite materials with arbitrary internal microstructures and...
Briefs: Information Technology
Forth Source Code Analysis Tool Set (FSCATS) is a computer program that provides a wide range of capabilities for documenting, analyzing, and reverse-engineering computer programs written in the Forth...
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Briefs: Electronics & Computers
Planar arrays of cadmium zinc telluride photodetectors with readout electronic circuitry have been developed for use as hard-x-ray and y-ray image sensors. When a coded,...
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Briefs: Materials
Ceramics Analysis and Reliability Evaluation of Structures/Creep (CARES/CREEP) is a computer program that predicts the creep lives of ceramic structural components. [CARES/CREEP should not be...
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Briefs: Physical Sciences
The presence of corrosives in the Earth's atmosphere is of global concern. From acid rains that are destroying forests and disfiguring monuments like the Parthenon and the pyramids, to atmospheric pollutants that produce...
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Briefs: Physical Sciences
Controlling Crystal-Growth Habit in Directional Freezing
A method of controlling the crystal-growth habit in directional freezing has been devised. A substance can be purified by directional-freeze crystallization, wherein (1) the liquid phase of the substance is partially frozen, causing impurities to become preferentially concentrated in the...
Briefs: Electronics & Computers
A transceiver has been developed to serve as a data-communication link between (1) the RS-232-standard serial communication port of a personal computer (PC) running the Windows 95 or Windows NT operating system...
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Briefs: Electronics & Computers
Special-purpose, "intelligent," computer-controlled, highly miniaturized radio transceivers have been proposed for use in monitoring critical and/or valuable pieces of equipment. These...
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Briefs: Electronics & Computers
A method of designing fault-tolerant networks of computers and other electronic circuits has been conceived with a view toward minimizing costs by utilizing commercial off-the-shelf (COTS)...
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