January 1999

Briefs: Electronics & Computers
Luneberg Lenses Made of Open-Cell Polyurethane Foams

A Luneberg lens is a microwave lens consisting of a series of concentric shells of differing dielectric constants. The highest dielectric constant, or refractive index, resides at the core and the lowest, at the outer shell. Microwaves passing through this arrangement of shells are focused in...

Briefs: Photonics/Optics
Video-Based Foreign Object Detection

The Boeing Company has developed an overhead camera system that can automatically spot small pieces of debris on a work surface that might otherwise go unnoticed. The system automatically analyzes inputs...

A prototype Stirling-engine regenerator containing a matrix made of carbon-fiber-based composite materials has been developed. The concept underlying this development effort is one of...

Briefs: Electronics & Computers
Fabry-Perot Fiber-Optic Temperature Sensor

A class of developmental photonic temperature-measuring systems is based on the use of miniature, fiber-optic-coupled Fabry-Perot interferometers as temperature transducers. These systems are...

Integrated electrochemical sensors are being developed for use in measuring concentrations of sulfur dioxide in gas mixtures. These sensors are based on the electrochemical oxidation of...

Briefs: Electronics & Computers
Dual-Function Microelectronic Sensors

Integrated-circuit image sensors of a proposed type would be capable of operation in either the wavelength band of 0.5 to 2.5 *m, the wavelength band of 2.8 to 5.8 *m, or both bands simultaneously....

Briefs: Software
Program Simulates Performance of a Hybrid Automobile

The Hybrid Electric Vehicle Analysis (HEVA) computer program numerically simulates the performance of an automotive vehicle -- especially a hybrid vehicle. A vehicle is said to be hybrid if (1) it contains an energy-storage device (a battery, flywheel, or ultra-capacitor) that is charged with...

An algorithm that processes bursts of data generated by scan-mode synthetic-aperture radar (scanSAR) offers some advantages over older scanSAR algorithms. With relatively high computational...

Briefs: Physical Sciences
Experiments on Flow in a Model Compressor Drum

A report discusses experiments on the flow of water along the interior of a transparent rotating cylindrical drum, the interior of which was partitioned into five cavities by disks with central holes and outer edges attached to the cylindrical drum wall. This water-flow model was designed to provide...

Improved silicon carbide-based Schottky diodes are undergoing development for use in detecting hydrocarbon (CxHy) and nitrogen oxide (NOx) gases at...

The figure shows a tension/compression structure that provides rigid suspension and a high degree of thermal isolation for a small instrument assembly used in low-temperature...

Briefs: Mechanical & Fluid Systems
Flutterometer for Flight Testing

A flutterometer is being developed for use as a data-analysis tool for flight flutter testing. The tool is based on an on-line implementation of a robust flutter-analysis technique, called the "* method,"...

Fiber-optic transceivers (FOTs) that can handle digital signals at any bit rate from 10 to 300 MHz have been developed. These variable-rate FOTs offer considerable advantages over fixed-rate FOTs that...

An alloy of 88Cu/8Cr/4Nb (numbers indicate atomic percentages) has been proposed for use in fabricating rocket-engine combustion chambers by vacuum plasma spraying (VPS). Relative...

Briefs: Physical Sciences
Electrostrictive Thermal Break Between Superfluid Reservoirs

A proposed technique would make it possible to maintain two reservoirs of superfluid helium at the same pressure but at different temperatures. Heretofore, a fountain effect (described below) has made this impossible. The proposed technique could be useful for low-temperature...

Briefs: Mechanical & Fluid Systems
Model of Response of Pressure Sensor in Rarefied Flow

A mathematical model represents the dynamic response of a pressure sensor that (a) comprises a transducer connected to a pressure-sensing port via a pneumatic tube and (b) is operated...

Briefs: Physical Sciences
In Situ Chemical Analysis via Acoustic-Emission Spectra

A method of in situ chemical analysis by use of small, simple, robust sensors has been proposed. The basis for the proposal is the discovery that chemical reactions emit acoustic waves, and that characteristic frequency spectra are associated with specific reactions. The acoustic...

The Multi-Board Module (MBM) scheme has been conceived to provide a cost-effective way to combine digital electronic circuits into dense, lightweight packages, within which high-speed...

Improved pulsed inductive plasma accelerators are undergoing development for use as long-life thrusters for propulsion of spacecraft on interplanetary missions and for maneuvering...

A noninvasive medical-imaging system produces false-color images that show regions of ischemia (reduced oxygenated blood flow) in organs and tissues. The system operates in real time, providing immediate...

The Boeing Company has developed wavelet-based image compression software that offers state-of-the-art compression of still imagery, providing superior image quality at compression ratios ranging from...

An ultrasonic-transducer fixture containing multiple pairs of fixed transducers, plus associated electronic transducer-multiplexing circuitry have been developed to accelerate the acquisition...

Briefs: Electronics & Computers
Solar-Cell System With High Conversion Efficiency

A concept for obtaining high energy-conversion efficiency in a solar photovoltaic system involves (1) concentration and spectral dispersion of sunlight and (2) use of several types of solar...

Briefs: Mechanical & Fluid Systems
Improved Mufflers for General Aviation

Innovative designs of mufflers for engines of small airplanes have been investigated in an effort to satisfy conflicting demands to maximize the reduction of exhaust noise while minimizing back pressure, size, and weight. Automotive-type muffler designs are not suitable for this purpose because they entail...

Briefs: Photonics/Optics
Dielectric Coating Grading Method

In a filing before the U.S. Patent and Trademark Office, the Boeing Company has disclosed a post-processing method for dielectric combiner elements that may reduce the cost of grading dual combiner sets by...

Briefs: Materials
Etching Solution for Removal of Silver Plating From Polymers

An etching solution has been developed for use in removal of silver plating from polymer-based (including composite-material) structural components, the surfaces of which are intended to serve as mirrors and waveguide structures. Such structures are often plated with aluminum, copper,...

Briefs: Robotics, Automation & Control
Performance of an Arc-Jet Thruster

A report discusses the design and testing of a laboratory-model arc-jet thruster designed to operate at a nominal power level of 300 W. This thruster is an intermediate product of continuing efforts to develop smaller, lower-power, higher-specific-impulse thrusters for use in a forthcoming generation of small...

Briefs: Medical
Neutrophil-Screening Assay Using Two-Color Flow Cytometry

An in vitro test that includes the use of two-color flow cytometry has been developed for use in screening of neutrophils for their ability to fight infections. Neutrophils constitute the first line of defense of the human body against infections. Neutrophils engulf invading bacteria in a...

An optical technique for measuring the concentration of soot in air is based on the cavity-ring-down (CRD) principle, which is so named because it involves observation of the decay...

Briefs: Information Technology
The SPEEDES Qheap: A Priority-Queue Data Structure

The Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES) is now using a new general-purpose priority queue data structure called the SPEEDES Qheap for managing its set of pending events in ascending time order. Empirical studies have shown this data structure to...

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