September 1999

Briefs : Mechanical & Fluid Systems
Deflection of Stretched Circular Membrane Under Pressure

Equations have been derived to describe the deflection of a circular membrane under both in-plane and transverse loads. More specifically, the equations describe the radial (in-plane) and perpendicular-to-the-plane deflections for the case of a circular membrane that has been stretched at...

Briefs : Software
Program for Designing Multiple-Reflector Antenna Systems

Millimeter-Wave Optics Design Tool (MOD Tool) is a computer program for analyzing and designing multiple-reflector antenna systems that operate at microwave and millimeter wavelengths. MOD Tool is intended for use in conjunction with a computer-aided-design (CAD) program along with other...

Briefs : Materials
Electrodialysis To Remove Ammonium Ions From Wastewater

Electrodialysis has been shown to be an effective means for removing ammonium ions from wastewater without use of consumable chemicals and without adding other substances to the treated water. Provided that continuing efforts to develop efficient electrodialysis equipment prove successful,...

Briefs : Mechanical & Fluid Systems
Hybrisol Rocket Engines

"Hybrisol" denotes a proposed rocket engine that would contain hybrid and solid-propellant parts within a single combustion chamber. ["Hybrid" as used here denotes a type of rocket engine in which a solid fuel is burned by use of a liquid or gaseous oxidizer and the flow of the oxidizer can be throttled to control the...

Briefs : Mechanical & Fluid Systems
Making Liquid Air in Small, Economical Quantities

A mixing apparatus combines liquid oxygen and liquid nitrogen to make liquid air in small, convenient quantities. Heretofore, equipment used to make liquid air by mixing was incapable of making batches smaller than 600 gallons (2,300 L). The present mixing apparatus produces liquid air on demand...

Briefs : Physical Sciences
Digitally Tunable Color Filters and Beam Scanners

Color-filtering and beam-scanning devices based on electro-optical switching of internal-reflection states have been proposed for use in display and measurement applications. Associated digital circuits would apply electronic control signals to spatial segments of these devices to obtain...

Briefs : Electronics & Computers
Software for Real-Time Display of Data via the Internet

The JGOAL collection of computer programs facilitates the real-time display, via the Internet, of multiple streams of data from the space shuttle and its ground support equipment at Kennedy Space Center. JGOAL is also readily adaptable to other applications that involve the real-time...

Briefs : Physical Sciences
Evaporation of Isolated and Collections of Fluid Drops Under Supercritical Conditions

A report presents a computational study of heat and mass transfer for isolated and interacting drops of one fluid (liquid O2) immersed in another fluid (H2) in finite, quiescent surroundings under supercritical conditions. The mathematical...

Briefs : Information Technology
Image Smoothing and Edge Detection Guided by Stereoscopy

A method of smoothing and edge detection in digitized images involves the use of a Gaussian smoothing filter that is adaptive in the sense that the filter scale varies with the estimated distance between each scene point and the camera. The estimate of distance is obtained via...

Briefs : Robotics, Automation & Control
Gimbaled Injectors for Testing Spacecraft Thrusters

A report proposes an assembly of gimbaled valve/nozzle subassemblies for use in injecting either a propellant fluid (e.g., monomethyl hydrazine) or a propellant-simulating fluid (e.g., water) into the combustion chamber of a spacecraft thruster during hot-fire or cold testing, respectively. The...

Briefs : Photonics/Optics
Hybrid Imaging Technology

"Hybrid imaging technology" (HIT) is the name of a discipline in which the advancement of electronic image sensors is pursued via hybridization of charge-coupled-device (CCD) and complementary metal oxide/semiconductor (CMOS) circuitry. The guiding principle of HIT is to combine CCD and CMOS components into units that...

Briefs : Physical Sciences
Improved Array of X-Ray Microcalorimeters

An improved array of microcalorimeters has been devised for use as photon detectors in an x-ray spectrometer for astrophysical research. The spectrometer will be used to measure the spectra of celestial objects in the "soft" x-ray range (photon energies from 200 eV to 10 keV), to a resolution much...

Briefs : Photonics/Optics
High-Speed Image Detectors With Subelectron Noise Floors

Parallel ultra-low-noise hybrid detectors (PHUDs) are developmental image-detector devices for use in low-power, scientific-grade video cameras. The hybrid nature of a PHUD lies in the incorporation of both charge-coupled-device (CCD) image-detection circuitry and complementary metal...

Briefs : Photonics/Optics
High-Quantum-Efficiency Photocathode for Photomultiplier Tubes

Photomultiplier tubes (PMTs) have long been recognized as the detector of choice for very weak light detection. The high gain of the PMT, in excess of 10 ×106, makes it a useful detector for applications such as LIDAR, bioluminescence, fluorescence, and chemiluminescence....

Briefs : Mechanical & Fluid Systems
Accelerations of One Airplane in Wake Vortices of Another

Accelerations of one airplane encountering a vortex or pair of vortices in the wake of another airplane were computed in a parametric study. The approach taken in the study was to systematically investigate the effects of progressively more nearly complete descriptions of the interaction...

Briefs : Information Technology
Automation Language for Managing Operations

Automation Language for Managing Operations (ALMO) is a computer program that assists a human operator at a central control station in monitoring and controlling a complex equipment system that includes multiple subsystems connected in a digital communication network. Still undergoing development, ALMO...

Briefs : Electronics & Computers
MAP- and Laurent-AMP-Based Carrier Synchronization in GMSK

An improved method of closed-loop synchronization of a radio receiver with the phase of a carrier signal modulated by Gaussian minimum-shift keying (GMSK) has been proposed. Synchronization of the receiver with the phase of the carrier signal ("carrier synchronization" for short) is...

Briefs : Software
Software for Analyzing Performance of a Gas Turbine Engine

A computer program provides capabilities for numerical simulation and analysis of the thermodynamic performance of aircraft or automotive gas turbine engines. The program was developed to utilize the turboshaft-engine experience base accumulated in aerospace disciplines for designing...

Briefs : Photonics/Optics
Prismatic Phase Shifter

The prismatic phase shifter is a novel device that can be used to control the phase of a coherent beam of light. Phase shifting is becoming an integral function of most modern interferometric systems. Phase shifting can be accomplished by use of any of a variety of older devices including moving mirrors, rotating...

Briefs : Information Technology
Characterizing Nonlinear Dynamics by Use of Wavelet Analysis

A method to detect and to characterize the type of nonlinear dynamics in an aeroelastic system involves the utilization of information from wavelet processing of measurement data. This method is intended to assist in identifying unmodeled dynamics of aircraft during flight testing.

Briefs : Physical Sciences
Miniature Ring-Orbitron Getter Ion Vacuum Pumps

Miniature ring-orbitron getter ion pumps have been proposed for supplying high vacuums to advanced scientific instruments expected to be developed in the next few years. Examples of such instruments include electron microscopes, ion mass spectrometers, and instruments based on electron probes.

Briefs : Materials
Mixed-Carbon Anodes for Improved Li-Ion Cells

Rechargeable lithium-ion electrochemical cells that contain anodes made from a mixture of graphite and carbon black have been found to perform better than do similar cells that contain anodes made of graphite alone. As explained in more detail below, the addition of carbon black improves performance...

Briefs : Physical Sciences
Using Rayleigh Scattering To Measure Spacecraft Attitude

Two reports describe a Rayleigh-scattering attitude sensor (RSAS) - an optoelectronic instrument for determining the orientation of a spacecraft. An RSAS comprises a telescope/video-camera/image-digitizer combination that is mounted on the spacecraft and that captures images of the limb of...

Briefs : Physical Sciences
Diagnosing Gas-Turbine-Like Combustion by Use of PLIF

A report describes experiments in which planar laser-induced fluorescence (PLIF) of hydroxyl radicals was used to study the structures of flames in burner test rigs (a flame-tube combustor and a sector combustor) under conditions like those in combustors of aviation gas-turbine engines. The...

Briefs : Software
Optimization of Vehicle Interior Noise Treatment

Automotive interior noise has become a critical consideration for manufacturers. Many studies have shown that interior noise in a vehicle has a major impact on the customer's perception of operation, performance, and quality. However, to reach desired interior sound levels, many manufacturers...

Briefs : Robotics, Automation & Control
Air-Purification System Utilizing Humidity Swings

A regenerable, low-power air-purification system has been proposed for (1) removing toxic gases from solid-waste-incinerator exhaust and/or (2) removing trace contaminants from breathable air. The system would include a primary gas adsorber that would be regenerated in a closed-loop...

Briefs : Manufacturing & Prototyping
Adaptable Drill Guide

The tool shown in the figure is a drill guide that can adapt to a curved or flat surface. The main function of the adaptable drill guide is to keep the axis of a drill perpendicular to the surface at the location of the hole to be drilled. The tool can also be used to guide a reamer into a drilled hole, to control the...

Briefs : Mechanical & Fluid Systems
Conservatism in Deterministic Structural Analysis

A paper discusses the excessive conservatism that has long been suspected to exist, because of the use of conventional (deterministic) safety factors, in the analysis and design of quasi-static structures. The origin of this conservatism is identified as a violation of statistical...

Briefs : Robotics, Automation & Control
A Precise Closed-Loop Temperature-Control System

A control system that includes a single thermal source has been designed to afford precise control of the temperature of a fluid flowing in a closed-loop system. Similar control systems could make it possible to increase production levels and to reduce risks in industrial situations in which...

Briefs : Physical Sciences
Lithium-Based Primary Cells for Low-Temperature Operation

A report describes an experimental study of the low-temperature electrical characteristics of commercial Li/MnO2, Li/CFx, Li/SO2, Li/SOCl2, and Li/BCX primary electrochemical cells. These high-energy-density cells are under consideration for use...

Briefs : Materials
Analysis of Progressive Failure in Laminated Composites

A computational methodology for predicting the initiation and propagation of failures in laminated matrix/fiber composite-material structures has been developed. The methodology follows the progressive-failure approach, in which it is recognized that a laminated composite structure can...

Briefs : Information Technology
Program for Designing a Mechanical System

Mechanical System Design/Analysis Tool (MSAT) is a user-friendly software system that facilitates and accelerates the processes of synthesizing and analyzing designs of mechanical systems. MSAT is particularly well suited for designing aircraft engines. MSAT can be used in the preliminary-design stage...

Briefs : Mechanical & Fluid Systems
Experiments on Vibration and Noise in Fuselages

A paper summarizes a continuing program of vibro-acoustic testing of two aircraft fuselage structures: (1) a 12-ft (3.7-m)-long generic aluminum test-bed cylinder that contains stiffening rings and stringers and (2) the 40-ft (12.2-m)-long fuselage of a 10-passenger turboprop airplane, made of...

Briefs : Information Technology
Development of Flight Software for Small Explorer Spacecraft

A report describes a continuing program of development of flight software for the attitude-control system (ACS) and the command-and-data-handling (C&DH) system of a prototype standard spacecraft of the Small Explorer (SMEX)-Lite class. Both the C&DH and ACS parts of the...

Briefs : Materials
Program Predicts Uncertainties in Properties of CMCs

Probabilistic Ceramic Matrix Composite Analyzer (PCEMCAN) is a user-friendly computer program that predicts uncertainties in the mechanical and thermal properties of ceramic-matrix composite (CMC) materials. These materials are candidates for fabrication of structural components that will be...


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