A combination of procedure and equipment for loading liquid hydrazine into a spacecraft fuel tank that contains a diaphragm or bladder would be modified, according to a proposal....

Briefs: Physical Sciences
Ultrasonic Bubble-Sizing Instrument

An ultrasonic instrument has been developed for measuring the sizes of bubbles in the human body. A primary example is that of bubbles associated with decompression sickness (the "bends"); these bubbles consist mostly of nitrogen and can occur in both blood vessels and extravascular tissues. The bubbles can...

A recently developed theoretical and computational method is especially well suited for analyzing time-series data that represent nonstationary and nonlinear processes. The method stands in...

Briefs: Materials
Development of Progressive-Failure-Analysis Software

A report discusses the development of the GENOA-PFA computer program, which was described in "Software for Simulating Progressive Fracture in Braided PMCs" (LEW-16845), NASA Tech Briefs, Vol. 24, No. 3 (March 2000), page 52; and "Update on a Progressive-Failure-Analysis Software System...

Briefs: Physical Sciences
Surface and Gas Temperatures via Multiwavelength Pyrometry

A report describes experiments using multiwavelength pyrometry to determine the surface temperature of the end tip inside a BeO cylinder that is part of a probe designed to measure high-temperature gases. The cylinder is heated by the gas into which it is inserted, and the gas...

Briefs: Physical Sciences
Tribology for Aerospace Applications

"Tribology for Aerospace Applications" is a textbook and reference source written for designers of rotating machinery; users and designers of such mechanical components as bearings, gears, and seals; tribologists; university and industrial researchers; and students of machine design. The book incorporates...

A method of fabricating composites of pretreated silicon carbide fibers in silicon carbide matrices provides for the formation of improved boron nitride fiber/matrix interfacial layers....

Briefs: Materials
Carbon-Filled EPDM Rubbers as Ablative Insulating Materials

Carbon-fiber-filled polymers made from ethylene propylene diene monomer (EPDM) have been found to be useful as ablative thermal-insulation materials. Like the silica-filled EPDM polymers described in the preceding article, these polymers have been investigated as candidates to replace...

Lightweight shields for electromagnetic interference (EMI) can now be fabricated from composites of (1) electrically conductive fibers made of bromine-intercalated graphite in (2) matrices...

Briefs: Materials
Composite-Material Pipes for Corrosive and Cryogenic Liquids

A flexible design concept and an associated method of fabrication have been conceived as means to satisfy growing demands for lightweight composite-material pipes for corrosive and cryogenic liquids. The design concept and method can be applied to produce piping systems capable of...

The figure presents a simplified and partly schematic view of a two-stage rolling-piston compressor that is undergoing development for use as the prime mover in a vapor-compression...

A proposed solenoid-actuated valve would open for a short time to pass a very small quantity of fluid. The valve could be used to meter a specified total quantity of the fluid through repeated...

Briefs: Manufacturing & Prototyping
Using Light To Fabricate Photonic Devices

A developmental apparatus and process for the fabrication of photonic devices utilize intense, focused laser light projected and/or diffracted in controlled patterns. The apparatus and process can...

Briefs: Motion Control
Formulation and Algorithm for Multi-Flexible-Body Dynamics

An improved formulation of the dynamics of multiple flexible bodies coupled via joints, and an algorithm that implements the formulation, have been developed at Johnson Space Center (JSC). A robot arm with multiple, somewhat flexible links is a prime example of a dynamic system to which...

In today's manufacturing world, the need for ultraprecise position measurement and control grows as feature sizes shrink in the semiconductor industry and the world of...

Briefs: Motion Control
Myoelectric Teleoperation for Robotics and Prosthetics

Johnson Space Center is sponsoring continuing research on the use of myoelectric signals to control dexterous robotic and prosthetic hands. This research is expected to advance the state of the art beyond that of today's most common, commercially available, myoelectrically controlled...

Briefs: Electronics & Computers
Microelectromechanical SPDT Switches

Microelectromechanical single-pole, double-throw (SPDT) switches with predominantly planar configurations have been proposed for use in radio-frequency (RF) circuits. These switches would have overall...

Briefs: Electronics & Computers
Making Submicron Features by Ion Etching Through PMMA Masks

Experiments have shown that a substrate can be patterned with submicron features by the following procedure:

Briefs: Materials
Reactive-Ion Etching of Smooth Vertical Walls in Silicon

An advanced technique of deep reactive-ion etching (DRIE) has been developed for fabricating smooth vertical walls in silicon wafers. These walls are suitable for use as bounding surfaces of optical waveguides in photonic and optoelectronic devices. The roughness of a typical 8-µm-high...

A Rankine-cycle engine that contains a binary working fluid (ammonia + water) and a recuperative heat exchanger has been built and tested. This engine is a prototype of...

NASA Dryden Flight Research Center has ruggedized and qualified an inexpensive commercial off-the-shelf (COTS) oxygen sensor that accurately and reliably aids assessment, in flight...

A device has been developed for measuring heat-transfer rates at many points underneath individual bubbles during boiling, in order to determine the heat-transfer coefficient as a function of...

The figure schematically depicts a flow-measurement system based on an acoustic sensor mounted on a pipe, along which flows a single or two-phase fluid. The electrical output of the...

Fiber-optic-coupled differential-pressure transducers are being developed for use in hot, harsh environments like those in the cores of aircraft turbine engines. The prior approach...

Two airborne spectrum analyzers were developed for acquiring dynamic data, characterized by frequencies up to 25 kHz, from a hypersonic-crossflow-transition experiment aboard the...

Briefs: Electronics & Computers
Improved Eye-Tracking Apparatus

A previously developed apparatus that tracks the orientation of the human eye has been modified to make it less susceptible to error induced by ambient infrared light. The apparatus is a commercial product intended primarily for use as a computer-control interface for a person who is physically unable to use a...

An algorithm has been devised to greatly simplify and improve the calibration and the reduction of systematic noise of an imaging interferometer or other similar interferometric instrument....

Briefs: Test & Measurement
Miniature Birefringence-Measuring System

A miniature birefringence-measuring system has been developed for use in investigating extensional flows of non-Newtonian polymers in microgravity. The system could also be used on Earth to perform...

Briefs: Information Technology
Software Collects Planning and Scheduling Requirements

Interim User's Requirements Collection (IURC) is a software system that generates an interactive graphical user interface that enables users of the International Space Station (ISS) to specify their payload-planning and -scheduling requirements via the World Wide Web (WWW). IURC...

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