Magazine

Tests have shown that modification of chemical compositions can increase the strengths and fracture toughnesses of solid oxide fuel-cell (SOFC) electrolytes. Heretofore, these solid electrolytes have been made of yttria- stabilized zirconia, which is highly conductive for oxygen ions at...

Virtual Real Time (VRT) is a computer program for testing embedded flight software by computational simulation in a workstation, in contradistinction to testing it in its target central processing unit (CPU). The disadvantages of testing in the target CPU include the need for an expensive test bed, the...

A second version of the Availability, Cost and Resource Allocation (ACARA) computer program has become available. The first version was reported in "System-Availability and Resource- Allocation Program" (LEW-15713), NASA Tech Briefs, Vol. 19, No. 8 (August 1995), page 54. To recapitulate:...

Formal Linear Algebra Recovery Environment is a computer program for high-performance, fault-tolerant matrix multiplication. The program is based on an extension of the prior theory and practice of fault-tolerant matrix·matrix multiplication of the form C = AB. This extension provides low-overhead...

A set of computer- program routines has been developed for calculating pressure drops and recoveries of flows through standard venturis, nozzle venturis, and orifices. Relative to prior methods used for such calculations, the method implemented by these routines offers greater accuracy because it...

A proposed hybrid (internal-combustion/ electric) automotive engine system would include as its internal-combustion subsystem, a modified Miller-cycle engine with regenerative air preheating and with autoignition like that of a Diesel engine. The fuel would be ethanol and would be burned...

Two papers describe the StarLight space interferometer — a Michelson interferometer that would be implemented by two spacecraft flying in formation. The StarLight formation flying interferometer project has been testing and demonstrating engineering concepts for a new generation of space interferometers that...

The term "plasma process diagnostics" (PPD) refers to a spectroscopic technique and sensing hardware that have been proposed for monitoring plasma processes used to fabricate electronic devices that feature sizes as small as several nanometers. Nanometer dimensions are characteristic of the...

An electrokinetic technique has been developed as a means of in situ remediation of soils, sludges, and sediments that are contaminated with heavy metals. Examples of common metal contaminants that can be removed by this technique include cadmium, chromium, zinc, lead, mercury, and...

A report discusses a network of spacecraft, in orbit around Mars, used to relay radio communications between Earth stations and mobile exploratory robots (rovers) as well as stationary scientific instruments that have been landed on the Mars surface. The relay spacecraft include two already in...

A report describes recent progress in a continuing effort to develop large reflectarray antennas to be deployed in space. Major underlying concepts were reported in two prior NASA Tech Briefs articles: "Inflatable Reflectarray Antennas" (NPO-20433), Vol. 23, No. 10 (October 1999), page 50 and...

The Ground Processing Scheduling System (GPSS) computer program is used to develop streamlined schedules for the inspection, repair, and refurbishment of space shuttles at Kennedy Space Center. A scheduling computer program is needed because space-shuttle processing is complex and it is...