January 2003

Briefs: Medical
Semiselective Optoelectronic Sensors for Monitoring Microbes

Sensor systems are under development for use in real-time detection and quantitation of microbes in water without need for sampling. These systems include arrays of optical sensors; miniature, portable electronic data-acquisition circuits; and optoelectronic interfaces between the...

Briefs: Physical Sciences
Evaluation of Charge Storage and Decay in Spacecraft Insulators

Two reports discuss methods for evaluating the magnitude of electrostatic charging that occurs in spacecraft dielectric materials (in particular, polyimides) during prolonged exposure to radiation in outer space. The reports describe experiments on the electrical resistivities and...

Hot-wire probes having dimensions of the order of nanometers have been proposed for measuring temperatures (and possibly velocities) in boundary-layer flows at spatial resolutions much finer...

Efforts are under way to develop deformable mirrors equipped with microscopic electrostatic actuators that would be used to maintain their reflective surfaces in precise shapes...

Briefs: Physical Sciences
Fiber-Optic Ammonia Sensors
Reversible, colorimetric fiber-optic sensors are undergoing development for use in measuring concentrations of ammonia in air at levels relevant to human health [0 to 50 parts per million (ppm)]. A sensor of this type includes an optical fiber that has been modified by replacing a portion of its cladding with a polymer...

The performance of a composite part is primarily determined by the orientation of fibers in the plies. Designers wishing to exploit the full potential of...

Briefs: Materials
Low-EC-Content Electrolytes for Low-Temperature Li-Ion Cells

Electrolytes comprising LiPF6 dissolved at a concentration of 1.0 M in three different mixtures of alkyl carbonates have been found well suited for use in rechargeable lithium-ion electrochemical cells at low temperatures. These and other electrolytes have been investigated...

High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition-metal nitrides (in...

Briefs: Electronics & Computers
Survivable Failure Data Recorders for Spacecraft

A spacecraft may be unable to communicate critical data associated with a serious or catastrophic failure. A brief report proposes a system, somewhat like a commercial aircraft "black box," for retrieving these data. A microspacecraft attached to the prime spacecraft would continually store recent...

Briefs: Electronics & Computers
Bit-Serial Adder Based on Quantum Dots

A proposed integrated circuit based on quantum-dot cellular automata (QCA) would function as a bit-serial adder. This circuit would serve as a prototype building block for demonstrating the feasibility...

Architectures that would exploit the distinct characteristics of quantum-dot cellular automata (QCA) have been proposed for digital communication networks that connect advanced digital...

A radio receiver system that features enhanced capabilities for remote sensing by use of reflected Global Positioning System (GPS) signals has been developed. This system was...

Briefs: Software
Software for a GPS-Reflection Remote-Sensing System

A special-purpose software Global Positioning System (GPS) receiver designed for remote sensing with reflected GPS signals is described in "Delay/Doppler-Mapping GPS-Reflection Remote-Sensing System" (NPO-30385), which appears on the previous page. The input accepted by this program comprises...

An optoelectronic system distributes a reference signal of low noise and highly stabilized phase and frequency (100 MHz) from an atomic frequency standard to a remote facility at a...

An improved method of calibration has been devised for instruments that utilize tunable lasers to measure the absorption spectra of atmospheric gases in order to determine the relative...

The figure is a simplified cross section of a microscopic optical switch that was partially developed at the time of reporting the information for this article. In a fully developed...

A simple, easy-to-use optoelectronic tool projects scale marks that become incorporated into photographic images (including film and electronic images). The sizes of objects...

A proposed method based on the use of a special-purpose diffractive optical element (DOE) would simplify (relative to prior methods) the alignment of three off-axis mirrors that constitute...

Briefs: Photonics/Optics
Laser Ranging Simulation Program

Laser Ranging Simulation Program (LRSP) is a computer program that predicts selected aspects of the performances of a laser altimeter or other laser ranging or remote-sensing systems and is especially applicable to a laser-based system used to map terrain from a distance of several kilometers. Designed to run in...

Briefs: Mechanical & Fluid Systems
Miniature Gas-Turbine Power Generator

A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric- power generators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about...

Briefs: Photonics/Optics
Theodolite With CCD Camera for Safe Measurement of Laser-Beam Pointing

The simple addition of a charge-coupled-device (CCD) camera to a theodolite makes it safe to measure the pointing direction of a laser beam. The present state of the art requires this to be a custom addition because theodolites are manufactured without CCD cameras as standard...

Pneumatically actuated miniature peristaltic vacuum pumps have been proposed for incorporation into advanced miniature versions of scientific instruments that depend on vacuum for...

A ladar-based system now undergoing development is intended to enable an autonomous mobile robot in an outdoor environment to avoid moving toward trees, large rocks, and other...

Briefs: Manufacturing & Prototyping
A Reactive-Ion Etch for Patterning Piezoelectric Thin Film

Reactive-ion etching (RIE) under conditions described below has been found to be a suitable means for patterning piezoelectric thin films made from such materials as PbZr1-xTixO3 or BaxSr1-xTiO3. In the original...

A process for transferring an entire wafer-level micromachined silicon structure for mating with and bonding to another such structure has been devised. This process is intended...

Briefs: Manufacturing & Prototyping
Pressure-Sensor Assembly Technique

Nielsen Engineering & Research (NEAR) recently developed an ultrathin data acquisition system for use in turbomachinery testing at NASA Glenn Research Center. This system integrates a microelectro-...

Briefs: Mechanical & Fluid Systems
Soft Landing of Spacecraft on Energy-Absorbing Self-Deployable Cushions

A report proposes the use of cold hibernated elastic memory (CHEM) foam structures to cushion impacts of small (1 to 50 kg) exploratory spacecraft on remote planets. Airbags, which are used on larger (800 to 1,000 kg) spacecraft have been found to (1) be too complex for...

Briefs: Mechanical & Fluid Systems
Energy-Absorbing, Lightweight Wheels

Improved energy- absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would...

Briefs: Mechanical & Fluid Systems
Viscoelastic Vibration Dampers for Turbomachine Blades

Simple viscoelastic dampers have been invented for use on the root attachments of turbomachine blades. These dampers suppress bending- and torsion-mode blade vibrations, which are...

Briefs: Information Technology
Quantum Search in Hilbert Space

A proposed quantum-computing algorithm would perform a search for an item of information in a database stored in a Hilbert-space memory structure. The algorithm is intended to make it possible to search relatively quickly through a large database under conditions in which available computing resources would...

A new method of robust, autonomous real-time diagnosis of a time-varying complex system (e.g., a spacecraft, an advanced aircraft, or a process-control system) is presented here. It is...

A new method of calculating the root-mean-square (rms) pointing jitter of a scientific instrument (e.g., a camera, radar antenna, or telescope) is introduced based on a state-space...

Briefs: Information Technology
Software for Estimating Costs of Testing Rocket Engines

A high-level parametric mathematical model for estimating the costs of testing rocket engines and components at Stennis Space Center has been implemented as a Microsoft Excel program that generates multiple spreadsheets. The model and the program are both denoted, simply, the Cost...

Briefs: Information Technology
Software for Building Models of 3D Objects via the Internet

The Virtual EDF Builder (where "EDF" signifies Electronic Development Fixture) is a computer program that facilitates the use of the Internet for building and displaying digital models of three- dimensional (3D) objects that ordinarily comprise assemblies of solid models created...

Briefs: Information Technology
CLARAty Functional-Layer Software

Functional-layer software for the Coupled Layer Architecture for Robotics Autonomy (CLARAty) is being developed. [CLARAty was described in "Coupled-Layer Architecture for Advanced Software for Robots" (NPO-21218), NASA Tech Briefs, Vol. 26, No. 12 (December 2002), page 48. To recapitulate: CLARAty was proposed...

Briefs: Information Technology
Java Library for Input and Output of Image Data and Metadata

A Java-language library supports input and output (I/O) of image data and metadata (label data) in the format of the Video Image Communication and Retrieval (VICAR) image-processing software and in several similar formats, including a subset of the Planetary Data System (PDS) image...

Briefs: Information Technology
"Virtual Cockpit Window" for a Windowless Aerospacecraft

A software system processes navigational and sensory information in real time to generate a three- dimensional- appearing image of the external environment for viewing by crewmembers of a windowless aerospacecraft. The design of the particular aerospacecraft (the X-38) is such that the...

InAs quantum-dot lasers that feature distributed feedback and lateral evanescent-wave coupling have been demonstrated in operation at a wavelength of 1.3 µm. These lasers are...

Two techniques have been proposed to increase the efficiency of coupling of light from lasers to Cassegrain telescopes and, in general, telescopes with secondary or tertiary mirror...

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