December 2000

Briefs : Electronics & Computers
The KSC Simulation System

The Kennedy Space Center (KSC) Simulation System is a computing system capable of large-scale mathematical modeling for real-time simulation of the behavior of a complex system that could include many different...

Briefs : Information Technology
Digital Library of NACA Reports

The NACA Technical Report Server (NACATRS) is both a node in the NASA Technical Report Server and a stand-alone World Wide Web (WWW) site. The NACATRS is dedicated to the preservation and dissemination of reports produced by the National Advisory Committee for Aeronautics (NACA).

Briefs : Information Technology
Finding Known Shapes in an Image by Pruning Parameter Space

An improved method of processing two- and three-dimensional image data to locate known shapes called "geometric primitives" involves (1) extraction of edges and other relevant image features and (2) performing a hierarchical search, in a space of parameters of equations that describe...

Briefs : Physical Sciences
Improved Infrared Imaging of Bulk Defects in CdZnTe Wafers

An improved method of infrared imaging of bulk defects in cadmium zinc telluride (CdZnTe) wafers has been developed. The method is intended primarily to be a means of identifying those portions of large CdZnTe wafers that are suitable to be "mined" for use in fabricating focal-plane...

Briefs : Physical Sciences
Image Generators With Compact Optics

Compact image generators that contain illumination sources and electronically controlled spatial light modulators have been invented. Compactness is achieved by folding of the optical paths that link the illumination sources, the spatial light modulators, and the viewing regions into which images are...

Briefs : Physical Sciences
Hand-Held Instrument for Imaging Hydrogen Fires

A hand-held instrument that contains two silicon-based charge-coupled-device (CCD) video cameras (see figure) has been developed for imaging hydrogen fires. This or a similar instrument is needed because the visible light emitted by a hydrogen fire is so dim that the fire cannot be seen by the...

Briefs : Physical Sciences
Improvements in Computed-Tomography Imaging Spectrometry

Two major improvements, described below, have been made in the construction and operation of a computed-tomography imaging spectrometer (CTIS). These plus future improvements can be expected to enhance the practicality and commercial viability of CTISs, which, in principle, offer...

Briefs : Information Technology
Program for Displaying Large, Coregistered Images

DataSlate is an easy-to-use Java-language computer program for displaying coregistered raster images representing large sets of data. The program includes a main viewing module that can display image data that have been converted into a special DataSlate format called "SimpleStruct" by use of an...

Briefs : Electronics & Computers
GA Synthesis of Circuits Using a Linear Representation

A method of automated synthesis of electronic circuits involves the use of a linear (as defined below) genome representation of circuit elements and of connections among them, plus a relatively simple unfolding technique, in conjunction with a genetic algorithm (GA). The method differs from...

Briefs : Electronics & Computers
Silicon Carbide npnp Thyristors

Thyristors (semiconductor controlled rectifiers) made from silicon carbide have been fabricated and tested as prototypes of power-switching devices capable of operating at temperatures up to 350 °C. The highest-voltage-rated of these thyristors are capable of blocking current at forward or reverse bias as large...

Briefs : Electronics & Computers
Small Lidar Altimeter Would Operate at Low Light Levels

A lidar apparatus called a microaltimeter has been proposed for use aboard a spacecraft in orbit around the Earth for mapping land and sea surfaces, including such features of special interest as ice, tree canopies, and flood plains. The microaltimeter is short for "microlaser altimeter"...

Briefs : Test & Measurement
Improved Methods of Testing Cryogenic Insulation Materials

Two improved methods have been developed for testing continuously rolled blankets and blanketlike thermal-insulation materials typically used in cryogenic vacuum systems. Both methods, and their corresponding apparatuses, are based on the cryogen boiloff calorimeter method according to...

Briefs : Test & Measurement
Real-Time Optoelectronic Particle-Fallout Monitors

Optoelectronic instruments for real-time, in situ monitoring of particle fallout are undergoing development. Settings in which these instruments could prove useful include clean rooms for assembly of optical and electronic equipment, food-packaging facilities, and other industrial facilities in...

Briefs : Test & Measurement
Program for Controlling Digital Instrumentation Recorders

A computer program enables the simultaneous monitoring and control of two commercial digital instrumentation recorders, each comprising a variable-rate buffer and a data tape recorder. The program can issue all standard tape-motion-related commands (fast forward, rewind, record, forward,...

Briefs : Software
Program Computes Tone Fan Noise From a Turbofan Engine

TFaNS is a computer program that predicts the tone noise that emanates from the fan stage of a turbofan engine. With the help of this program, engineers working to reduce fan tone noise can study the effects of proposed design changes and are thus more likely to be successful in their...

Briefs : Software
Software for Generating 100-by-100-km Images From SAR Data

SAR Processing System Precision Processor (SPS PP) is one of the computer programs used in the Alaska SAR Facility (ASF) [where "SAR" means "synthetic-aperture radar"] to generate image data products. SPS PP ingests data that have been received from the RADARSAT (a Canadian...

Briefs : Software
Sequencing and Job-Control Software for Processing SAR Data

The SAR Processing System Control Processor (SPS CP) computer program performs sequencing and job-control functions within the Alaska SAR Facility (ASF) [where "SAR" means "synthetic-aperture radar"]. SPS CP interacts with the Product-Distribution-and-Management (PDM) system of...

Briefs : Software
Software for Processing RADARSAT ScanSAR Data Into Images

SAR Processing System ScanSAR Processor (SPS SSP) is a computer program that is used in the Alaska SAR Facility (ASF) to processes scanSAR downlink data from the RADARSAT (a Canadian Earth-observation satellite) into a suite of image data products. ["SAR" means "synthetic-aperture...

Briefs : Software
Software for Wafer-Level Testing of Microfabricated Devices

Prober Assistant Measurement System (PAMS) is a computer program that automates the time-consuming process of testing microfabricated devices (integrated circuits and/or microelectromechanical systems) at the wafer level. PAMS was written specifically for use with the Karl Suss...

Briefs : Information Technology
RS Forward Error Correction for Variable-Length Frames

A method of forward error correction by Reed-Solomon (RS) coding has been devised to increase the link margins of data-communication systems that must handle variable-length frames or packets of data. Heretofore, RS coding has involved fixed-length blocks: In order to encode variable-length...

Briefs : Information Technology
Fast NRZLM Encoding and Decoding Algorithm

A recently developed algorithm saves encoding and decoding time in the operation of data-communication systems that utilize the NRZM code, which is derived from the better-known non-return-to-zero-level (NRZL) code. This algorithm utilizes lookup tables that contain the results of routine encoding and...

Briefs : Electronics & Computers
Generating Electric Power From Alpha-Particle Sources

Small electric power cells based on the direct conversion of kinetic energy of alpha particles into electricity have been proposed. These cells are expected to function continuously over long times and at temperatures from -250 to 600 °C. They would be made from semiconductors that are...

Briefs : Motion Control
Manually Operated Weld-Filler-Wire Feeder

A simple, manually operated mechanical device will ensure a smooth and predictable motion when feeding filler wire into a molten weld pool in gas tungsten arc welding (GTAW). This device simplifies and/or reduces the requirements for a dexterous hand to hold and manipulate filler wire. This device will...

Briefs : Motion Control
Asymmetric Dual-Axis Goniometer for Positioning on a Sphere

The ability to position an object at various locations corresponding to a portion of a spherical surface has long been accomplished using nested goniometers, in which, as observed from above, the apparent motion is readily described in a Cartesian ("XY") frame. In certain applications,...

Briefs : Motion Control
Multiple-DOF Surface-Acoustic-Wave Piezoelectric Motors

Surface-acoustic-wave (SAW) piezoelectric motors capable of operating in multiple degrees of freedom (DOFs) simultaneously have been proposed. A particularly useful motor of this type could provide both linear and rotary motions. Another particularly useful motor of this type would feature...

Briefs : Electronics & Computers
Second-Generation Spaceborne Rainfall-Profiling Radar System

"PR-2" denotes a proposed spaceborne radar system for measuring three-dimensional rainfall profiles and rainfall velocities. The PR-2 system would incorporate a number of improvements over the precipitation radar (PR) system now operating aboard the satellite of the Tropical Rainfall...

Briefs : Electronics & Computers
Improved System for Locating Lightning Strikes Within Meters

A system for determining the locations of nearby lightning strikes from electric-field and acoustic measurements has been developed. This system evolved from the system described in "System Locates Lightning Strikes to Within Meters" (KSC-11992), NASA Tech Briefs, Vol. 24, No. 7 (July...

Briefs : Motion Control
Electrohydrodynamic Pumping Enhances Operation of Heat Pipe

Experiments have shown that electrohydrodynamic pumping can be utilized to increase the heat-transport capacity of a heat pipe. More specifically, electrohydrodynamic pumping can be used to increase the flow of liquid to the evaporator section of the heat pipe; the increased flow helps...

Briefs : Electronics & Computers
High-Performance Photodetector Circuit for Doppler Lidar

A photodetector circuit has been built for use in the receiver portion of a continuous-wave infrared Doppler lidar system for atmospheric research. As in nearly all Doppler lidar systems, the detection of the return signal in this system involves heterodyning, in a photodetector, with a...

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