A comprehensive library of technical briefs from engineering experts at NASA and major government, university, and commercial laboratories covering all aspects of innovations in electronics, software, photonics, imaging, motion control, automation, sensors, test, materials, manufacturing, mechanical, and mechatronics.

Briefs : Physical Sciences
Computer Program Automates Thermal Analyses

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 National Aerospace Plane (NASP), and the crew return vehicle (CRV). Heretofore, thermal analyses of the...

Briefs : Physical Sciences
Automated Generation of Acoustic-Propagation Computer Codes

A computer program written within the Mathematica software system automatically generates FORTRAN computer codes that numerically simulate, with high accuracy, the acoustical physics of complex unbounded three-dimensional or bounded two-dimensional flow fields. The program is a...

Briefs : Physical Sciences
Rule-Based "Intelligent" Monitoring Software

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 F-18, X-31, LASRE, and X-33 programs.

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...

Briefs : Information Technology
Software for Analyzing Forth Programs

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 programming language. FSCATS also aids in the management of software, estimating costs of software, and...

Briefs : Electronics & Computers
Cadmium Zinc Telluride Detectors for Imaging of Gamma Rays

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, x-and-y-ray-opaque aperture mask is positioned in front of such a sensor, the resulting assembly is an instrument that...

Briefs : Materials
Program Predicts Creep Lives of Ceramic Components

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 confused with the related program CARES/LIFE, which was described in "Program for Evaluation of...

Briefs : Physical Sciences
Vapor Corrosion Cell

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 smog and induce emphysema in a significant number of people, the introduction of corrosives and other...

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
RS-232-to-Infrared Transceiver

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 and (2) a remote infrared transceiver that is capable of operation at a baud rate < MHz. The...

Briefs : Electronics & Computers
"Intelligent" Transceivers Would Predict Failures of Parts

Special-purpose, "intelligent," computer-controlled, highly miniaturized radio transceivers have been proposed for use in monitoring critical and/or valuable pieces of equipment. These transceivers and associated electronic circuits would perform both diagnostic and prognostic monitoring...

Briefs : Electronics & Computers
Networks Based on Stack-Tree Topology and a 1394 Bus

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) products and standards for all system and component interfaces. The method involves, more specifically,...

Briefs : Electronics & Computers
Absolute Position Encoders Using Pattern Recognition

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 microlithography, optical projection, charge-coupled-device (CCD) array image detection, and image...

Briefs : Motion Control
Motion-Measuring Circuit for a Vibratory Capacitive Sensor

The figure illustrates an improved electronic circuit that generates a signal proportional to either the instantaneous vibrational velocity or the instantaneous position (equivalently, the instantaneous vibrational displacement) of a vibratory capacitive sensor of the type discussed in...

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...

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;...

Briefs : Motion Control
Vibration-Regulating Circuit for a Mechanical Resonator

The figure illustrates an improved electronic circuit that excites constant-magnitude vibrations in an electrostatically actuated, capacitively sensed mechanical resonator. The circuit can be adapted, for example, to a planar vibratory microgyroscope like the one described in the preceding...

Briefs : Motion Control
Using Commercial-Grade Tb/Dy in Magnetostrictive Actuators

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 mechanical devices. These actuators offer many advantages over piezoelectric actuators and actuators using...

Briefs : Motion Control
Circuit Generates Rotation Signal From a Vibratory Gyroscope

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 microgyroscopes and other sensory devices that include electrostatically actuated, capacitively sensed...

Briefs : Electronics & Computers
Resonant Crackwires for In Situ Monitoring of Jet Engines

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 resonant crackwires." Inasmuch as uncontained turbine failures are the leading engine-related hazard for...

Briefs : Motion Control
Q-Compensation Circuit for a Planar Vibratory Microgyroscope

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 two preceding articles. That is, the circuit makes the scale factor of the gyroscope (the factor of...

Briefs : Test & Measurement
Instrument Measures Fluorescence From Chlorophyll in Plants

An optoelectronic instrument, known as a plant fluorescence sensor, is being developed for use as a working tool in agricultural settings. This instrument is a remote, passive monitor that provides a means of discerning plant stress at very early stages. With sufficient warning, the...

Briefs : Electronics & Computers
On-Chip Correction for Defective Pixels in an Image Sensor

A method of correcting for defective pixels in an integrated-circuit image sensor of the active-pixel sensor (APS) type has been proposed. The corrections would be made by additional readout circuitry on the image-sensor chips. By making it unnecessary to discard sensor chips that...

Briefs : Mechanical & Fluid Systems
Surface Micromachined Silicon Carbide Accelerometers

Surface micromachined silicon carbide accelerometers are undergoing development for eventual use in high-temperature environments like those inside turbines, internal-combustion engines, and other machines. These accelerometers would be used to measure vibrations indicative of deterioration of...

Briefs : Physical Sciences
Software for Predicting Behavior of a Pyrotechnic Actuator

A theoretical model that predicts the time-dependent behavior of a pyrotechnically actuated mechanism and a computer program that implements the model have been developed. The model and program are especially applicable to a pyrotechnic device known as the NASA Standard Initiator (NSI)....

Briefs : Physical Sciences
Dither Sensing for Controlling a Segmented-Mirror Telescope

Image-plane multidither sensing has been found to be suitable for adaptive wavefront correction in a large telescope in which the main optic is a precise reflector divided into lightweight, controllably actuated segments. In image-plane multidither sensing, the telescope is aimed at a...

Briefs : Physical Sciences
Self-Temperature-Compensated Ceramic Strain Gauges

Ceramic static-strain gauges capable of generating mechanical-strain signals much larger than spurious thermal signals have been invented. These gauges are intended for use at temperatures from room temperature to 1,250 °C. Heretofore, external circuits have been used to provide temperature...

Briefs : Physical Sciences
"Set and Hold With Power Off" Cryogenic Actuators

Magnetostrictive actuators that would hold their displacements with power turned off have been proposed for use at temperatures from about 10 to about 77 K. Such "set and hold with power off" actuators are attractive for effecting fine position adjustments in cryogenic scientific instruments,...

Briefs : Electronics & Computers
Electrobiotic Toxic-Agent Sensors

Electrobiotic sensors have been proposed for detecting toxic substances in a variety of environments. Electrobiotic sensors would be inexpensive, compact units that would be easy to use and could be deployed either singly or in large numbers, depending on the size of an environment to be monitored and/or the...

Briefs : Electronics & Computers
Magnetoelectric Sensors and Electric Generators

Electric generators and magnetic-field sensors of a proposed type would be based on the magnetoelectric effect. A simple device of this type (see figure) would consist mainly of an inner layer of a magnetoelectric material sandwiched between two outer layers of a ferromagnetic material. Electrical...

Question of the Week
Would You Cook with ‘Julia?’