November 2000

Briefs : Materials
Polyaniline Compounds for Protection Against Corrosion

Corrosion of iron and steel substrates can be inhibited by coating them with any of the wide variety of compounds denoted generally as polyanilines. A polyaniline suitable for this type of application can be in either an electrically conductive salt (doped) form or an electrically...

Briefs : Software
Program Predicts Jet Noise

MGBK is a computer program that predicts the mixing noise and the shock noise generated by a subsonic or low-supersonic jet, given input data on the mean flow and turbulence fields as predicted by a suitable state-of-the-art computational fluid dynamics (CFD) program. More specifically, MGBK can be regarded as a...

Briefs : Software
Program for Analyzing Static Transmission Error of Helical Gears

The computer program HeliStat performs finite-element analysis to simulate meshing of helical gears. This program is a logical extension of the program DANST, which applies to spur gears. [DANST was described in "Computing Stresses in Spur Gears (LEW-15420), NASA Tech Briefs, Vol....

Briefs : Software
Software for Multidisciplinary Analysis of Optical Systems

Integrated Modeling of Optical Systems (IMOS) is a MATLAB™ computer program that provides many functions for analysis of a system represented by mathematical models of its thermal, structural, control, and/or optical aspects. For example, IMOS can be used to study thermal distortion of...

Briefs : Software
Software for Multidisciplinary Analysis of Graded Composites

The Coupled Structural/Thermal/Electromagnetic (CSTEM) computer program implements an integrated multidisciplinary approach to analysis and optimization of the designs of graded composite-material structures. The name of the program reflects recognition of the coupling among thermal,...

Briefs : Electronics & Computers
Electrically Isolating, Thermally Coupling Devices

Integrated signaling devices of a proposed type would utilize thermal coupling to transfer digital signals between electronic circuits that are required to be kept electrically isolated from each other. The proposed devices would be implemented as silicon-on-insulator complementary metal...

Briefs : Materials
Improved Coatings for Flexible Insulating Blankets

"ACE" (for "advanced ceramic engineered") denotes a type of coating mate-rial that increases the ability of flexible thermal-insulation blankets to resist erosion. Developed for use on the insulating blankets on the space shuttle orbiters, these coating materials could also be used on similar...

Briefs : Electronics & Computers
Improved Ignitor and Keeper Power Supplies for Hall Thruster

Ignitor and keeper power supplies have been developed specifically for a Hall-effect thruster with a cold cathode. Prior to the development of these power supplies, difficulties had been observed in the operation of cold-cathode Hall thrusters; in particular, they did not start...

Briefs : Test & Measurement
Helium Leak Detector With Improved Sample-Delivery System

The figure schematically depicts a portable helium leak detector that includes an improved sample-delivery system. This instrumentation is designed for detecting leaks in the fuel and oxidizer systems of the space shuttle main engines. In a helium leak test, helium is used as a tracer gas...

Briefs : Test & Measurement
Fiber-Optic Sensors for Measuring Oxygen Dissolved in Water

Fiber-optic sensors for measuring concentrations of oxygen dissolved in water are undergoing development. In comparison with electrochemical dissolved-oxygen sensors, the fiber-optic sensors are expected to be easier to use and maintain. Also, unlike electrochemical dissolved-oxygen...

Briefs : Test & Measurement
Gas Analyzer Measures Concentrations of H2, O2, and H2O

An apparatus measures small concentrations of H2, O2, and H2O in flowing He gas. In the original application for which the apparatus was developed, the flow of He gas is used to purge a tube through which liquid hydrogen is transferred:

Briefs : Electronics & Computers
Development of a Range-Safety Smart System

Range Safety Officers (RSOs) are used by NASA and other government agencies to assure protection of life and property during launch operations. The current decision-making system used by the RSOs at NASA Wallops Flight Facility (WFF) and the National Ranges, including the Eastern Range (ER) and...

Briefs : Software
Program Traces Rays With Quadruple Precision

QRAYPKS is a general-purpose FORTRAN optics-analysis computer program that enables the computation of path lengths to an unprecedented level of precision. The impetus for developing QRAYPKS was the need to mathematically model an outer-space laser interferometer to be used in detecting gravitational...

Briefs : Materials
PBO Fiber Blends: A Promise for the Future

Woven fabrics comprising polybenzoxazole (PBO) fibers blended with other selected fibers have been found to exhibit combinations of properties that, in some applications, may be superior to those of fabrics made from either PBO alone or the other materials alone. This finding is the result of an...

Briefs : Mechanical & Fluid Systems
Air-Displacement Volumometer With Soft Sides

An air-displacement volumometer with soft sides has been devised for measuring the volume of a human body. This apparatus could be useful in hospitals, medical research laboratories, clinics, athletic facilities, and the like. It could also be used to measure the volumes of irregularly shaped objects...

Briefs : Mechanical & Fluid Systems
Improved Methodology for Dynamics of Orbiter Payload Bay Doors

The Payload Bay Door Dynamics Simulation (PBDS) computer program simulates the mechanical behavior of the space-shuttle payload bay doors and their latching and driving mechanisms during opening, closing, latching, and unlatching. PBDS was developed to replace an older program that...

Briefs : Mechanical & Fluid Systems
Computer-Controlled Power Tool

The figure depicts the exterior appearance of a pistol-grip rotary power tool that can be used to turn a drill bit, wrench socket, screwdriver, or other tool bit clockwise or counterclockwise at a controlled speed or torque. This tool is an updated version of the one described in "Pistol-Grip Torques-Measuring...

Briefs : Mechanical & Fluid Systems
Technique for Controlling Gas Generation in a Bioreactor

A pressure-swing technique has been developed for controlling the generation and flow of gas in an anaerobic biological reactor and associated equipment in a system that processes wastewater. The purpose and effect of the technique is to prevent the formation of gas bubbles in the reactor;...

Briefs : Physical Sciences
Passive Radiative Cooler for Use in Outer Space

The figure depicts a passive radiative cooler designed for use in outer space. The design of this device conjoins radiative and conductive thermal-isolation features, which, in further conjunction with a favorable spacecraft attitude and on-orbit thermal environment, can be utilized to cool...

Briefs : Physical Sciences
Magnetically Enhanced Propellant Isolator for Ion Sources

A magnetically enhanced, high-voltage propellant isolator has been conceived for incorporation into materials-processing or space-based ion systems. The high-voltage isolator is needed to provide electrical isolation between the ion source, typically at high voltage, and the gas-feed...

Briefs : Physical Sciences
Buoy Instrumented for Spectral Measurement of Water Quality

An instrumented buoy measures selected aspects of the spectrum of upwelling light for assessment of "water quality." The buoy carries a previously patented optical-backscatter probe that contains a hyperspectral sensor. The output of the probe is processed by a small onboard computer....

Briefs : Physical Sciences
Magnetostrictive Heat Switches Actuated by Flux Tubes

In a proposed improvement on the basic concept of a magnetostrictive heat switch for cryogenic applications, the magnetic field needed for actuation would be generated by a superconducting flux tube (SFT). A closely related concept for a magnetostrictive heat switch was presented in...

Briefs : Physical Sciences
Liquid Shell Insulation

A new concept called "liquid shell insulation" has been proposed as a means of temporary thermal protection for scientific instrument probes that are required to operate for short times in hot, high-pressure environments. Liquid shell insulation was conceived to protect probes that would be dropped from spacecraft to...

Briefs : Physical Sciences
Magnetostrictive Valves Actuated by Flux Tubes

Magnetostrictive valves for cryogenic applications would be actuated by superconducting flux tubes (SFTs), according to a proposal. The reasoning behind this proposal closely tracks that of the proposal to use SFTs in magnetostrictive heat switches, as reported in the preceding article.

Briefs : Information Technology
Linking Employee Appraisals to Organizational Goals

The Goal Performance Evaluation System (GPES) is an Internet-based automated management information system (see figure) now undergoing development at Kennedy Space Center (KSC). The GPES is designed to perform two major functions:

Briefs : Software
Program Summarizes Operational Data From a Complex System

Engineering Data Summarization Flight Software is a computer program designed for use aboard a spacecraft to implement a concept, called "beacon monitoring," that has been discussed in several prior NASA Tech Briefs articles. The program generates summaries of operational data (e.g.,...

Briefs : Information Technology
Neural-Network Approach to Analysis of Sensor Data

A method of processing of time-series data from sensors that monitor a dynamic physical system has been devised to enable detection of anomalies in the dynamics. The method involves computing what are initially supposed to be dynamical invariants that represent the structural and operational...

Briefs : Software
Software for Acquiring Data on Dynamics of Magnetic Bearings

A computer program controls the automated acquisition, display, and reduction of data on the dynamics of magnetic bearings. The data gathered by use of this program are expected to enable the verification and enhancement of mathematical models of magnetic-bearing dynamics, thereby...

Briefs : Physical Sciences
Fluorometer for Analysis of Photosynthesis in Phytoplankton

An instrument that measures the characteristic lifetime of fluorescence of chlorophyll has been invented for in situ, real-time oceanographic studies of photosynthesis in phytoplankton. The basic design and principle of operation lend themselves to development of the instrument as a...

Briefs : Information Technology
Program for Visualization and Exploration of Scientific Data

WebWinds is an interactive computer program that aids the visualization and exploration of scientific data. WebWinds is the successor to LinkWinds, which was reported in "LinkWinds — Flexible Software for Highly Interactive Visual Data Analysis" (NPO-19786), NASA Tech Briefs, Vol....

Briefs : Photonics/Optics
Phonon-Assisted Quantum-Well Infrared Photodetector

A proposed quantum-well infrared photodetector (QWIP) would exploit resonant-phonon-assisted transitions to reduce dark current significantly below that of a typical previously developed QWIP operating at the same wavelength and temperature. The reduction in dark current would translate to...

Briefs : Photonics/Optics
Frequency-Converting Photonic Link With BSSA Amplification

A photonic system has been devised for acquiring a radio-frequency (RF) signal from a remote receiving antenna via a long optical fiber. The system performs multiple functions, including upward or downward frequency conversion, optical amplification [more specifically, Brillouin...

Briefs : Photonics/Optics
Coupling Light Between Optical Fibers and Noncircular Beams

Cylindrical lenses can be used to increase the efficiency of coupling of light between (1) beams with circular or nearly circular cross sections propagating in single-mode optical fibers and (2) free-space beams with noncircular cross sections and with different radii of curvature of...

Briefs : Photonics/Optics
Fast Infrared Spectrometer

A spectrometer has been developed for acquiring transient emission and absorption spectra in the wavelength range from 1.2 to 5.0 µm. It could be used to characterize flames, turbulence, and other transient phenomena that interact with infrared radiation. Heretofore, success in the study of such phenomena has been...

Briefs : Photonics/Optics
Imager With Motion-Artifact Suppression and Antiblooming

An improved photodiode-based complementary metal oxide/semiconductor (CMOS) active-pixel sensor (APS) incorporates features to (1) allow imaging with very high electronic shutter speeds, (2) suppress motion artifacts, and (3) prevent image lag and blooming (the spread of image lag to the...

Briefs : Photonics/Optics
Improved Illumination Device for Inspecting Window Surfaces

A fiber-optic illumination device that aids the inspection of window surfaces has been improved to make it suitable for automated detection of pits, scratches, and subsurface damage by use of a machine-vision and image-analysis system. The improvements, which include modifications in...

Briefs : Photonics/Optics
Photodiode-Based CMOS APSs With Zero-Lag, Low-Noise, High-Linearity Design

Two improved schemes for the design and operation of photodiode-based CMOS (complementary metal oxide/ semiconductor) active-pixel sensors (APSs) afford zero image lag, low noise, and high linearity of response even under low illumination. Figure 1 schematically depicts...

Briefs : Photonics/Optics
Whispering-Gallery-Mode Microspheres as Light Modulators

Light modulators of a proposed type would exploit the propagation of lightin "whispering-gallery" electromagnetic modes in microspheres made of electro-optical materials. These modulators would offer advantages of ultrahigh modulation efficiency and increased bandwidth, relative to their...

Briefs : Photonics/Optics
Electrodeposition of Strong Glassy Metals

Thin-walled structures made of strong glassy nickel and glassy nickel-cobalt alloys, with tailorable low residual stresses, and with high resistance to permanent plastic deformation, can be formed by use of an electrodeposition process. This process was developed to enable the fabrication of lightweight,...

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