September 1998

Briefs : Materials
Metal- and Oxide-Containing Carbons Made From Graphite Oxide

Carbon-based materials containing, variously, metals and metal oxides can be synthesized according to a method that involves reactions of metal chlorides with materials of general composition COx. In a typical material synthesized by the present method, the carbon is porous...

Briefs : Robotics, Automation & Control
Methodology for Optimizing Designs of Rotating Turbine Disks

A methodology for optimizing the fundamental structural designs of rotating turbine disks has been developed to aid in preliminary evaluations of various gas-turbine-engine designs. The basis for this methodology is a combination of turbine-disk and low-cycle-fatigue methodologies that...

Briefs : Robotics, Automation & Control
Rib Valve as Shutter for Air Swirler in Combustor Nozzle

A rib valve is under consideration for use as a shutter in an air swirler in the fuel nozzle of a variable-geometry combustor. In the original application, the variable-geometry combustor would be part of an engine in the High-Speed Civil Transport. In this application, the rib...

Briefs : Software
Simulation by Logical Modeling of Costs

The Simulation by Logical Modeling of Costs (SIBYL/COST) software subsystem is used by logistical and financial analysts to develop cost projections of labor and hardware requirements for preparation of space shuttle main engine (SSME) spares proposals, SSME program operating plans (POPs), and special...

Briefs : Electronics & Computers
Switching Protocol for Optical Packet Data Communication

The figure illustrates aspects of a proposed switching protocol for optical packet data communication that would serve as an alternative to the older store-and-forward and header-first protocols. In both older protocols, it is necessary to store a single header from each packet of data...

Briefs : Mechanical & Fluid Systems
Flush Airdata Sensing System for the X-33 Aerospace Vehicle

A novel airdata system based on flush-mounted pressure sensors has been developed for the X-33 aerospace vehicle. Denoted the "X-33 flush airdata sensing" (FADS) system, it was designed to overcome limitations of pitot-static probes that were used previously, as explained below.

Briefs : Materials
MoSi₂-Based Composite Materials for Aircraft Engines

MoSi2-based composite materials are among the advanced materials undergoing development as potential strong, stiff, lightweight replacements for the nickel-based superalloys now used in aircraft engines. Of the MoSi2-based composites, the most promising ones include...

Briefs : Robotics, Automation & Control
Walking Robot for Internal Inspection of Thin-Wall Ducts

A walking robot connected to external instrumentation via a tether has been proposed to enable visual inspections, retrieval of loose objects, and some repairs inside thin-wall round ducts. The ducts in question are made of sections about 4 ft (1.2 m) long, joined by flexible seals that...

Briefs : Electronics & Computers
Automated Cargo-Tracking Transponders

Credit-card-sized electronic transponders have been proposed for use in tracking cargo anywhere on Earth. A transponder would be carried on a cargo container, where it would act as a "smart tag." The transponder would store data on the cargo in the container and would respond to inquiries —whether local or...

Briefs : Robotics, Automation & Control
Biomorphic Explorers

"Biomorphic explorers" are a class of proposed small robots that would be equipped with microsensors and would feature animallike adaptability and mobility. These robots would capture key features, a specific design or function found in nature, taking advantage of general animal mechanical designs and neural functions that...

Briefs : Physical Sciences
Computer-Controlled Instrumentation Measures Hydrogen Leaks

An instrumentation system monitors rates of leakage of hydrogen from multiple zones on a complexly shaped tank. Each zone is established by bagging a designated exterior portion of the tank. The bag for each zone is purged with a carrier gas (either nitrogen or helium) at a controlled...

Briefs : Electronics & Computers
Optoelectronic Generation of Optical and Microwave Signals

The figure schematically illustrates an optoelectronic apparatus that generates both an optical output and an electronic output (typically at frequencies in the range from hundreds of megahertz to tens of gigahertz). The apparatus is denoted a "coupled opto-electronic oscillator" (COEO)...

Briefs : Mechanical & Fluid Systems
Program Facilitates Simulation of Flows of Cryogenic Fluids

EASY/ROCETS is a developmental computer program for mathematical modeling and analysis of dynamic flows of cryogenic fluids in a rocket-engine-testing facility. Heretofore, the numerical simulation of such flows has been accomplished by use of computer codes specific to test-equipment...

Briefs : Physical Sciences
Using CT Data in Finite-Element Models of MMC Components

X-ray-based Computed Tomography (CT) has been linked with finite-element analysis to provide a capability for structural characterization of as-manufactured parts— especially for the nondestructive evaluation of metal-matrix composite (MMC) material parts. In some cases, this capability...

Briefs : Information Technology
Robust Aeroservoelastic-Stability Margins

In aeroservoelastic (ASE)-stability analysis, one considers the coupling of the aerodynamic, inertial, structural, actuation, and control-system elements of the dynamics of an aircraft. The closed-loop interactions of these elements can introduce unexpected instabilities in flight if the analytical model...

Briefs : Electronics & Computers
Ultrathin Packaging of Multiple Integrated-Circuit Chips

A process being developed for ultrathin packaging of multiple integrated-circuit chips and associated microelectromechanical components makes it possible to fabricate a minimally invasive pressure-measuring instrument to be used in characterizing a boundary-layer flow inside a...

Briefs : Physical Sciences
Remote In-Flight Infrared Imaging for Analyzing Surface Flows

The feasibility of remotely acquiring infrared images (thermograms) of aircraft surfaces in flight to locate flow-transition boundaries has been investigated. As used here, "remotely" means that the infrared instrumentation is mounted aboard an observing aircraft that flies along with...

Briefs : Electronics & Computers
Fabrication of Thinned QWIP Arrays for Improved Performance

Focal-plane-array (FPA) hybrids of quantum-well infrared photodetectors (QWIPs) thinned to the membrane level are undergoing development. The developmental QWIPs in question are of the kind that exploit bound-to-quasi-bound absorption, as described, for example, in "Bound-to-Quasi-Bound...

Briefs : Electronics & Computers
Engine Monitoring Based on Normalized Vibration Spectra

An electronic engine-health-monitoring system is based on (1) computation of frequency-phase-normalized (FPN) spectra from the digitized outputs of vibration sensors and (2) the use of these spectra as feature vectors, which are presented to an artificial neural network for recognition of...

Briefs : Physical Sciences
Optical Remote Detection of Ice on Aircraft Surfaces

An imaging spectroscopic technique is undergoing development for use in remote detection of ice and mapping of the thickness of ice on aircraft surfaces. The technique is based on the variation of local spectral reflectance with the depth of ice and/or water on a surface of known aircraft...

Briefs : Information Technology
Algorithm for Initialization of a Convolutional Decoder

An algorithm effects rapid initialization of a convolutional decoder. This algorithm can be applied "on the fly"; that is while the decoder is receiving a stream of convolutionally encoded data. In comparison with other means of initialization, this algorithm is simpler, and it can be...

Briefs : Electronics & Computers
Embedded CMOS A/D Converters for High-Speed Operation

Sarnoff Corporation has announced the development of four new analog-to-digital (A/D) converter macro cells for embedding in CMOS designs in which high-precision, high-speed operation at low power is important. The 8-bit, 10-bit, 12-bit, and dual 6-bit designs are available for licensing by...

Briefs : Electronics & Computers
Parallel-Processing CDMA Detector With Neural Network

A proposed improved code-division multiple-access (CDMA) detector would achieve high resistance to jamming of weak ("far") received signals by strong ("near") ones. The problem of such jamming is called the "near/far problem," and resistance to such jamming is called "near/far resistance."...

Briefs : Physical Sciences
Transparent Furnaces for High-Temperature Research

Transparent furnaces are being developed for use in research on properties and processing of materials at high temperatures. Full optical access to the interiors of furnaces is intended to provide the capability for nonintrusive diagnosis and feedback control of the subtleties of...

Briefs : Information Technology
Improved Parallel Computation of Electromagnetic Scattering

An improved method of parallel computation of the electromagnetic-scattering characteristics of complexly shaped objects has been devised. This method belongs to a class of methods that involve the finite-element solution of Maxwell's equations on unstructured grids. ("Unstructured...

Briefs : Electronics & Computers
Bound-to-Quasi-Bound Quantum-Well Infrared Photodetectors

Multiple-quantum-well AlxGa1 - xAs photodetectors that exploit transitions of electrons from quantum-well bound states to quasi-bound states are undergoing development for use at wavelengths from 6 to 25 µm. These photodetectors are intended to provide detectivities...

Briefs : Electronics & Computers
Sensor Combines Technologies to Achieve Application Versatility

By combining patented digital Silver-in-Glass® and analog conductive plastic technologies in a single environmentally sealed unibody package, Spectrol Electronics' DigiSense™ provides thousands of application-specific multifunction outputs (Figure 1). The conductive plastic...

Briefs : Physical Sciences
Measurements of Radiation in the Atmosphere

The recent summit meeting held in Kyoto, Japan, has brought world-wide attention to the issue of global climate change. For the past 5 years, the Department of Energy's Atmospheric Radiation Measurement - Unmanned Aerospace Vehicle (ARM-UAV) Program has been investigating the largest source of...

Briefs : Electronics & Computers
"Smart" Camera for Precise Mapping and Targeting

A "smart" video camera, called the "GI-Eye," generates digital image data that are automatically tagged with georegistration meta-data to indicate the precise position and attitude of the camera when the image was taken. This automatic georegistration streamlines the processing of the digital...

Briefs : Motion Control
Improved Roller and Gear Drives for Robots and Vehicles

Two types of gear drives have been devised to improve the performances of robotic mechanisms. One type features a dual-input/single-output differential-drive configuration intended to eliminate stick/slip motions; the other type features a single-input/dual-angular-momentum-balanced-output...

Briefs : Motion Control
Electrostatic Displacement Control Compensates for Spring

The figure schematically illustrates part of an accelerometer in which a feedback control subsystem applies voltages to generate electrostatic forces to minimize the displacement of a proof mass suspended on a spring. Older systems of this type provide active control of the displacements...

Briefs : Information Technology
Converting Particle-Fallout Data to Obscuration Levels

A worksheet has been constructed within the Microsoft Excel software system for converting raw particle-fallout data into percentages of obscuration; that is, percentages of areas obscured by particles on surfaces. These obscuration levels are needed for assessing contamination levels in...

Briefs : Electronics & Computers
Signal Preprocessor for Determining Time of Arrival

A proposed analog/digital circuit would improve the accuracy of determining the time of occurrence of a peak in an analog waveform. In the past, the time of occurrence of the peak was determined by comparing the magnitude of digital data samples. The time or clock pulse associated with the peak...