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.

A methodology for predicting stresses and the resultant cracking in plasma-sprayed thermal-barrier coatings (TBCs) has been developed. The methodology is built around a computer code that...

Experiments have shown that ultrasound could be an effective means of enhancing the removal of chlorinated hydrocarbon contaminants from groundwater by the zero-valent-metal treatment...

The magnetic/extendible boom docking aid is an improved mechanism that enables two spacecraft to capture and structurally mate with each other without inducing the large (and...

Briefs: Mechanical & Fluid Systems
Vapor-Compression Solar Refrigerator Without Batteries

A solar-powered vapor-compression refrigeration system developed for Johnson Space Center operates without batteries. The design of this system will make the cost of solar-powered refrigeration systems competitive and enable the use of such systems in long-distance spaceflights, military...

Briefs: Manufacturing & Prototyping
Thermal-Stress Technique for Cutting Thin Glass Sheets

A technique based on the generation of highly localized thermal stresses has been devised as a means of cutting both flat and curved glass sheets of thicknesses between 30 and 600 µm. The technique is reliable, accurate, and economical. The technique can be used, for example, to cut thin...

The microwave-sterilizable access port is an apparatus that functions in a simple, quick, and reliable manner to reduce significantly the risk of contamination during transfer of materials into or out of...

Briefs: Medical
Treatment With Ferrates Eliminates DNA and Proteins

Ferrate (VI) salts have been proposed for use in sterilizing water (perhaps also in sterilizing air). The iron in ferrate (VI) salts is in its highest oxidation state (VI), and these salts are extremely strong oxidants. In laboratory experiments, it was shown that treatment of DNA solutions...

Briefs: Physical Sciences
All-Pressure Fluid-Drop Model Applied to a Binary Mixture

A report presents a computational study of the subcritical and supercritical behaviors of a drop of heptane surrounded by nitrogen, using the fluid-drop model described in "Model of a Drop of O2 Surrounded by H2 at High Pressure" (NPO-20220) and "The Lewis Number...

Briefs: Physical Sciences
Validation of All-Pressure Fluid-Drop Model

A report presents a computational study of the subcritical and supercritical behaviors of a drop of heptane surrounded by nitrogen. The subject matter is basically same as that of the report described in the preceding article, except that the Lewis-number issue is not addressed in detail; however, this...

Briefs: Information Technology
Generating Commands for the Mars Polar Lander Robotic Arm

A report discusses the use of the Web Interface for Telescience (WITS) for visualization and command sequence generation in the Mars Polar Lander (MPL) mission. WITS, which has been described in prior articles in NASA Tech Briefs, is an Internet-based software system that enables...

Briefs: Electronics & Computers
The Future of Electronic Device Design

An article discusses anticipated advances in the design of increasingly capable integrated circuits containing ever smaller electronic devices. The article emphasizes the emergence of technology computer-aided design (TCAD) — a discipline in which computer-aided design is combined with computational...

Briefs: Materials
Multi-Shock Blankets for Protecting Spacecraft

A report discusses multi-shock blankets, which are under investigation for use in protecting spacecraft against orbiting debris from prior spacecraft missions. Multi-shock blankets are described in comparison with early protective metallic "bumpers" and with a somewhat more recent invention called...

Briefs: Mechanical & Fluid Systems
Airlocks for Pressurized Rovers

A report presents a survey of the design engineering and scientific literature on airlocks and on planetary-exploration vehicles ("rovers"), from the perspective of evaluating existing and potential design concepts for airlocks for pressurized rovers. The airlocks are the key to designing a pressurized rover...

Briefs: Medical
Spacecraft-Facility Microbes Tolerate H2O2, NaCl, and Heat

A report describes experiments that were performed to isolate and characterize microbes that survive conditions of controlled circulation of air, desiccation, low nutrient concentrations, and moderately high temperatures in a spacecraft-assembly facility. These conditions are more severe...

Briefs: Materials
Study of High-Performance Polyimide Foams

This report describes an experimental study of thermal-stability, mechanical, and flammability properties of foams of several different densities made of three different polyimides. The study was performed because (1) prior such studies were performed on polyimide films rather than foams and (2)...

Briefs: Physical Sciences
Subgrid Analysis of Mixing Layer With Evaporating Droplets

This report presents an analysis of a database from computational simulations of a droplet-laden mixing layer (i.e., evaporating droplets of a liquid fuel in air) undergoing a transition to turbulence. The basic governing equations were those of transport of discrete droplets through a...

Briefs: Physical Sciences
Validated Model of a Fluid Drop for All Pressures

The report "A Validated All-Pressure Fluid Drop Model and Lewis Number Effects for a Binary Mixture" presents one in a series of theoretical and computational studies of the subcritical and subpercritical behaviors of a drop of fluid and, in particular, a drop of heptane surrounded by nitrogen...

A prototype ring laser in which a transparent microsphere serves as an electromagnetic-mode selector has been constructed in a continuing effort to develop optoelectronic...

A class of proposed photonic switching devices would utilize interactions among light bullets that have been studied theoretically. Because they function at speeds much greater than those of...

The figure depicts an example of a proposed type of optoelectronic oscillator (OEO) based on some of the same principles as those described in the preceding article. In the proposed...

An assembly that includes electromechanical rotary actuators has been developed specifically for use as the shutter mechanism of a cryogenic infrared camera that will be part of an...

Optoelectronic oscillators (OEOs) of a proposed type would be based partly on the use of fiber-optic linear or ring resonators in place of the long fiber-optic delay lines that have...

Briefs: Electronics & Computers
The NASA Spacecraft Transponding Modem

A report describes the NASA Spacecraft Transponding Modem (STM) — a spacecraft transponder now under development for planned use on deep-space missions scheduled for launch in the year 2003. In comparison with a traditional deep-space transponder, the STM will be smaller and less power hungry; the...

An analog very-large-scale integrated (VLSI) circuit was designed and built to implement Hebbian synapses with an improved method of modifying and storing the synaptic weights, for...

Briefs: Electronics & Computers
Design of a Highly Reliable Controller for an I2C Bus

The design of a highly reliable controller for a digital data bus incorporates improvements, in both hardware and software, over the basic design of a low-speed, low-power, serial bus known in the industry as "I2C." ("I2C" signifies "inter integrated circuit bus" — a...

Briefs: Information Technology
Advances in Parallel Computing on Adaptive Grids

Five papers address interrelated topics in parallel computing and the use of adaptive, unstructured computational grids. The titles of the papers and their general subject matters are the following:

Figure 1 depicts a compact enclosure enabling the operation of personal-computer (PC)-based electronic circuits in harsh environments. The electronic circuits in question are...

A method of arraying of receiving radio antennas involves utilization of all of the signal information available across a broad spectral band that includes any signal(s) of interest. As used...

An array of monolithically fabricated nanoklystrons has been proposed as a frequency-agile and/or redundant source of electromagnetic radiation at frequencies ranging from about 0.3...

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