February 2000

Briefs : Medical
Wearable Sensor Patches for Physiological Monitoring

Wearable sensor patches — miniature biotelemetric units — have been proposed for use in measuring temperature, heart rate, blood pressure, and possibly other physiological parameters. The sensor patches would be small and could be mass-produced inexpensively by use of state-of-the-art...

Briefs : Physical Sciences
Rayleigh-Scattering Measurement of Temperature and Velocity

Figure 1 schematically depicts an experimental setup in which Rayleigh scattering from molecules of a flowing gas is used to measure the temperature and one component of the velocity of the gas. The Rayleigh-scattering apparatus in this setup is capable of operation in the harsh...

Briefs : Electronics & Computers
Integrated Optical Voltage-Measuring Apparatus

An integrated optical voltage-measuring apparatus based on a Mach-Zehnder interferometer has been designed and constructed. The main feature of this apparatus is that optical fibers link part of it to an optical sensor head placed at the source of the voltage to be measured, whether the source be a...

Briefs : Electronics & Computers
Integrated Test and Operations System

The Integrated Test and Operations System (ITOS) is a generic system of software for controlling spacecraft and components of spacecraft during development, testing, and operation in orbit. The ITOS software is an inexpensive, portable, highly configurable system that runs under a variety of UNIX operating...

Briefs : Physical Sciences
Software for Precise Ultrasonic Contact Measurements

The ULTRA SON computer program is designed for use in precise ultrasonic contact scan measurements for nondestructive characterization of materials. This program performs major functions necessary for controlling an ultrasonic apparatus, analyzing the measurement data generated by the...

Briefs : Electronics & Computers
Apparatus Records Acceleration and Temperature

An apparatus records triaxial acceleration and temperature as a function of time, operating unattended for as long as 3 weeks on power supplied by two D cells. The apparatus, which has dimensions of only 3.5 by 4.5 by 2.2 in. (8.9 by 11.4 by 5.6 cm) and weighs only 28.5 oz (0.81 kg) is designed...

Briefs : Electronics & Computers
DRAM Circuit Tolerates Single-Event Upsets

A dynamic random-access memory (DRAM) circuit that tolerates single-event upsets (SEUs) has been developed. A single-event upset is a bit flip caused by ionizing radiation. In a DRAM, the state of each bit (0 or 1) is stored as charge on a buried capacitor. The impingement of an energetic charged...

Briefs : Electronics & Computers
Two Approaches to Improvement of InGaAs/InAlAs/InP HEMTs

Researchers are following two approaches in an effort to improve the low-noise performances of InP-based high-electron-mobility transistors (HEMTs) that could be used as front-end amplifiers in millimeter-wave receivers. These devices are designed to operate while cooled to temperatures...

Briefs : Electronics & Computers
Electronic Modules With a 3-D Interconnection Scheme

An improved three-dimensional (3-D) scheme for modular packaging and interconnection of electronic circuits has been proposed to overcome deficiencies of an older scheme and to obtain additional advantages. In particular:

Briefs : Software
Software for Monitoring Remote Systems and Executing Plans

The Knowledge Server Tools (KST) computer program comprises a distributed set of software tools for monitoring remote systems. Part of KST implements a knowledge server for monitoring the status of a remote system (e.g., a computer-controlled instrumentation system, a robot, or...

Briefs : Software
Monocoque Tank Analysis Spreadsheet System, Version 2.0

The Monocoque Tank Analysis Spreadsheet System (MONTASS) computer program is an integrated software system that incorporates Microsoft Excel worksheet software and Visual BASIC software. MONTASS was developed to enable rapid analysis and preliminary design of structural domes and...

Briefs : Software
Automated Planning and Scheduling for a Robotic Vehicle

A software system generates sequences of commands for the operation of a robotic vehicle. The system was adapted to control Rocky 7, a semiautonomous instrumented vehicle of the "rover" type used in scientific exploration of Mars. The software system was developed by integrating two...

Briefs : Materials
Protective Shells for Composite Overwrapped Pressure Vessels

White Sands Test Facility (WSTF) scientists have developed an energy-absorbing laminated shell that is a prototype of lightweight, inexpensive, and removable covers to shield and otherwise protect carbon-composite overwrapped pressure vessels (COPVs). Although COPVs are superior to...

Briefs : Materials
Nonevaporable Getters To Maintain Vacuum in Sealed MEMS

Nonevaporable getters have been proposed for use in maintaining vacuum inside hermetically sealed microelectromechanical systems (MEMS) that rely on vacuum for proper operation. A vibratory microgyroscope is an example of such a MEMS. The proposed getters could also be used in such vacuum...

Briefs : Mechanical & Fluid Systems
Spherical-Coordinates Encoder Module

The spherical-coordinates encoder module (SCEM) is a relatively simple and inexpensive electromechanical apparatus for quickly and easily measuring three-dimensional offsets between objects at distances of the order of a few feet ( ≈1 m). The SCEM was developed specifically for measuring offsets between...

Briefs : Medical
Improved Sensor Pills for Physiological Monitoring

Improved miniature biotelemetric units resembling large pills have been proposed for use in physiological monitoring of the gastrointestinal tract. The broad principles of design, operation, and inexpensive mass production of these sensor pills would be the same as those of the sensor patches...

Briefs : Medical
Urine-Sample-Collection Device for Use on the Space Shuttle

The in-flight urine collection absorber (IUCA) is a Johnson Space Center (JSC) breakthrough. It features a lightweight, compact design and is easy to use for collection of urine samples by male and female space shuttle crewmembers. The IUCA is superior to currently available hardware...

Briefs : Physical Sciences
AlGaN Photodiodes Respond to Ultraviolet C

Solar-blind photodetectors respond only to ultraviolet light at wavelengths shorter than those of the solar radiation that can penetrate atmosphere of the Earth. This wavelength range, traditionally defined as wavelengths

Briefs : Physical Sciences
Parallel 3D EMPIC Algorithm Using Nonorthogonal Grids

Electromagnetic particle-in-cell (EMPIC) codes provide a capability for numerically simulating the motions of electrically charged particles in electromagnetic fields, and hence have become standard software tools in plasma physics research. Most existing EMPIC codes are based on the use of...

Briefs : Information Technology
Parameterizing Shape Perturbations for Multidisciplinary Design Optimization

A recently developed method of parameterizing complex shapes that one seeks to optimize differs from prior such methods in two major respects: (1) instead of entirely parameterizing the shapes, one parameterizes only shape perturbations (deformations of initial or...

Briefs : Electronics & Computers
Low-Power, Fast Machine Vision System on a Single IC Chip

A versatile, ultrafast, low-power machine vision system in the form of a single integrated-circuit chip has been proposed for use in military targeting, industrial robotics, and other applications in which there are requirements for utilizing visual information in real time. The...

Briefs : Electronics & Computers
Special-Purpose Interface for Fast Writing on a Hard Disk

A special-purpose interface circuit for a computer hard-disk drive (HDD) enables rapid writing of image data from a scientific instrument to sequential sectors on the hard disk. The design of this interface exploits the fact that most of the hardware and software components typically used...

Briefs : Electronics & Computers
SIBless Interface Design for Space-Station Training Computer

NASA has developed a system of hardware and software that can accommodate all necessary interfaces between (1) space-station flight computers and (2) a simulation host computer used in training, with the least host-computer processing overhead, least cost, and least complexity. This...

Briefs : Electronics & Computers
Forward-Link/Simulator PCI Card

The forward-link/simulator card (FLS) performs the fundamental satellite-telemetry data-transmission function for the forward (Earth-to-spacecraft) link in real time at rates up to 400 Mb/s. The FLS also simulates a Consultative Committee for Space Data Systems (CCSDS) telemetry data source that outputs data at...

Briefs : Motion Control
Radio-Frequency Wireless Flight-Control System

Technological advances have driven the evolution of aircraft flight-control systems. In the dawn of 20th-century aviation, the Wright Brothers used cables and warping of wing surfaces to change the shapes of flight-control surfaces. As engineers designed aircraft capable of flying faster, higher,...

Briefs : Photonics/Optics
Lightweight Reflector Dishes Would Be Made by Spin Casting

Lightweight reflector dishes for radio antennas would be mass-produced cheaply by spin casting of polymers, according to a proposal. These reflector dishes were conceived for compact stowage followed by deployment and operation aboard spacecraft, but might also be useful on Earth in...

Briefs : Photonics/Optics
Retroreflective Communication Systems

A retroreflective communication system (RCS), is a state-of-the-art system that provides (1) two-way optical communication using only one transmitter and (2) multipath communication among remote locations. RCSs were conceived for use in communication among stations on the ground and aboard spacecraft in...

Briefs : Robotics, Automation & Control
Adaptive Variable Bias Control for Magnetic Bearings

Adaptive variable bias control (AVBC) is an improved technique for controlling the currents supplied to the electromagnets in magnetic bearings. In AVBC, the bias currents are varied in such a way as to reduce overall power consumption.

Briefs : Motion Control
MEMICA: a Concept for Reflecting Remote-Manipulator Forces

The term "mechanical mirroring using controlled stiffness and actuators" ("MEMICA") denotes a developmental concept for reflecting contact forces, displacements, mechanical damping, and temperature from the hand of a remote robotic manipulator back to the hand of a human operator who...

Briefs : Photonics/Optics
Low-Sidelobe Phased-Array-Fed Cylindrical-Reflector Antenna

A phased-array-fed cylindrical-reflector antenna with superquadric projected aperture has been designed to afford the ability to scan the beam over a wide angular range without having to resort to a large focal-to-diameter ratio and without incurring excessively strong sidelobes. The...

Briefs : Photonics/Optics
SiC-Based Black-Body Absorbers for Submillimeter Wavelengths

Open-cell silicon carbide foam coated with a ferrite-filled absorbing resin has been found to be useful for black-body absorbers at millimeter and submillimeter wavelengths. The panels can be used as calibration targets for radiometers that operate at these wavelengths.

Briefs : Motion Control
Mass-Produced Hollow Cathodes Will Cost Less

A commercial version of the NASA plasma-contactor hollow-cathode assembly (PC HCA) has been developed. The NASA PC HCA is a highly reliable hollow discharge cathode that is the most thoroughly understood, tested, and mature of all hollow cathodes that have been considered for use in electric...

Briefs : Photonics/Optics
Adaptive Filtering of SAR Interferograms

An algorithm for filtering synthetic-aperture-radar (SAR) interferograms has been developed which substantially improves the performance of subsequent phase-unwrapping. It accomplishes this task by filtering the interferogram strongly in areas where the scene contains little detail, and weakly where the...

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