September 2004

A holographic technique has been devised for generating a visible display of the effect of exposure of a photorefractive crystal to γ-rays. The technique exploits the space charge that results...

A digital averaging phasemeter has been built for measuring the difference between the phases of the unknown and reference heterodyne signals in a heterodyne laser interferometer....

A prototype improved external cavity laser (ECL) was demonstrated in the second phase of a continuing effort to develop wavelength-agile lasers for fiber-optic communications and...

Briefs: Photonics/Optics
Optoelectronic Instrument Monitors pH in a Culture Medium

An optoelectronic instrument monitors the pH of an aqueous cell-culture medium in a perfused rotating-wall-vessel bioreactor. The instrument is designed to satisfy the following requirements:

Briefs: Mechanical & Fluid Systems
Demonstration of a Pyrotechnic Bolt-Retractor System

A paper describes a demonstration of the X-38 bolt-retractor system (BRS) on a spacecraft-simulating apparatus, called the Large Mobility Base, in NASA Flight Robotics Laboratory (FRL). The BRS design was proven safe by testing in NASA Pyrotechnic Shock Facility (PSF) before being demonstrated...

Briefs: Mechanical & Fluid Systems
Simulating Operation of a Planetary Rover

Rover Analysis, Modeling, and Simulations (ROAMS) is a computer program that simulates the operation of a robotic vehicle (rover) engaged in exploration of a remote planet. ROAMS is a rover-specific extension of the DARTS and Dshell programs, described in prior NASA Tech Briefs articles, which afford...

Briefs: Mechanical & Fluid Systems
Silicone-Rubber Microvalves Actuated by Paraffin

Microvalves containing silicone-rubber seals actuated by heating and cooling of paraffin have been proposed for development as integral components of microfluidic systems. In comparison with...

Briefs: Mechanical & Fluid Systems
Flexible Shields for Protecting Spacecraft Against Debris

A report presents the concept of Flexshield —a class of versatile, light-weight, flexible shields for protecting spacecraft against impacts by small meteors and orbiting debris. The Flexshield concept incorporates elements of, but goes beyond, prior space-craft-shielding concepts,...

Briefs: Mechanical & Fluid Systems
Controllable Curved Mirrors Made From Single-Layer EAP Films

A document proposes that light-weight, deployable, large- aperture, controllable curved mirrors made of reflectively coated thin electroactive-polymer (EAP) films be developed for use in spaceborne microwave and optical systems. In these mirrors, the EAP films would serve as both...

The figure depicts the major functional blocks of a system, now undergoing development, for conditioning neural signals acquired by electrodes implanted in a brain. The overall...

It has been shown that a non-square (NS)22n+1-ary (where n is a positive integer) quadrature amplitude modulation [(NS)22n+1-QAM] has inherent memory that can be...

Simple, passive instruments have been developed for measuring the exposure of material specimens to vacuum ultraviolet (VUV) radiation from the Sun. Each instrument contains a silicon...

An apparatus and technique have been devised for measuring the radiation pattern of a microwave patch antenna that is one of a number of identical units that have been...

The figure depicts an apparatus for mechanical testing of nuts In the original application for which the apparatus was developed, the nuts are of a frangible type designed for use with...

Briefs: Information Technology
Further Improvement in 3DGRAPE

"3DGRAPE/AL:V2" denotes version 2 of the Three - Dimensional Grids About Anything by Poisson's Equation with Upgrades from Ames and Langley computer program. The preceding version, 3DGRAPE/AL, was described in "Improved 3DGRAPE" (ARC-14069) NASA Tech Briefs ,Vol.21, No.5 (May 1997), page 66....

Briefs: Information Technology
Ground Support Software for Spaceborne Instrumentation

ION is a system of ground support software for the ion and neutral mass spectrometer (INMS) instrument aboard the Cassini spacecraft. By incorporating commercial off - the - shelf database, Web server, and Java application components, ION offers considerably more ground - support - service...

Briefs: Information Technology
MER SPICE Interface

MER SPICE Interface is a software module for use in conjunction with the Mars Exploration Rover (MER) mission and the SPICE software system of the Navigation and Ancillary Information Facility (NAIF) at NASA's Jet Propulsion Laboratory. (SPICE is used to acquire, record, and disseminate engineering, navigational, and other...

Briefs: Information Technology
Analyzing Contents of a Computer Cache

The Cache Contents Estimator (CCE) is a computer program that provides information on the contents of level-1 cache of a PowerPC computer. The CCE is configurable to enable simulation of any processor in the PowerPC family. The need for CCE arises because the contents of level-1 caches are not available to...

Briefs: Information Technology
Discrepancy Reporting Management System

Discrepancy Reporting Management System (DRMS) is a computer program designed for use in the stations of NASA's Deep Space Network (DSN) to help establish the operational history of equipment items; acquire data on the quality of service provided to DSN customers; enable measurement of service performance;...

Product development is becoming increasingly global and as a result, new challenges have emerged, such as coordinating geographically dispersed teams of...

Briefs: Physical Sciences
Part 2 of a Computational Study of a Drop-Laden Mixing Layer

This second of three reports on a computational study of a mixing layer laden with evaporating liquid drops presents the evaluation of Large Eddy Simulation (LES) models.

A proposed technique for locating concealed objects (especially small antipersonnel land mines) involves the acquisition and processing of spectral signatures over broad microwave...

A solution has been formulated to preserve deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in specimens of blood, saliva, and other bodily fluids. Specimens of this type are...

A rapid, sensitive test using chemiluminescent oligodeoxynucleotide probes has been developed for detecting, identifying, and enumerating intact cells. The test is intended especially...

Briefs: Materials
Brazing SiC/SiC Composites to Metals

Experiments have shown that active brazing alloys (ABAs) can be used to join SiC/SiC composite materials to metals, with bond strengths sufficient for some structural applications. The SiC/SiC composite coupons used in the experiments were made from polymer-based SiC fiber preforms that were chemical-vapor-...

Briefs: Materials
Composite-Material Tanks With Chemically Resistant Liners

Lightweight composite-material tanks with chemically resistant liners have been developed for storage of chemically reactive and/or unstable fluids — especially hydrogen peroxide. These tanks are similar, in some respects, to the ones described in — Lightweight...

Modifications of BN-based coatings that are used as interfacial layers between the fibers and matrices of SiC-fiber/SiC-matrix composite materials have been investigated to improve the...

In a proposed advance in friction stir welding, the torque exerted on the workpiece by the friction stir pin would be measured and controlled in an effort to measure and control the...

Briefs: Manufacturing & Prototyping
Setup for Visual Observation of Carbon-Nanotube Arc Process

A simple optical setup has been devised to enable safe viewing of the arc and measurement of the interelectrode gap in a process in which carbon nanotubes are produced in an arc between a catalyst-filled carbon anode and a graphite cathode. This setup can be used for visually guided...

Briefs: Manufacturing & Prototyping
Manufacturing High-Quality Carbon Nanotubes at Lower Cost

A modified electric-arc welding process has been developed for manufacturing high-quality batches of carbon nanotubes at relatively low cost. Unlike in some other processes for making carbon nanotubes, metal catalysts are not used and, consequently, it is not necessary to perform...

Briefs: Manufacturing & Prototyping
Thermally Conductive Metal-Tube/Carbon-Composite Joints

An improved method of fabricating joints between metal and carbon-fiber-based composite materials in lightweight radiators and heat sinks has been devised. Carbon-fiber-based composite...

Features: Photonics/Optics
Nano-Optics

Nano-optics is a valuably novel class of technology that takes advantage of light’s unique interaction with subwavelength, nano-scale patterned materials, and nanotechnology-enabled fabrication methods to create a broadly...

Question of the Week
Will Self-Erasing Chips Catch On?

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