A comprehensive library of technical briefs from engineering experts at NASA and major government, university, and commercial laboratories covering all aspects of innovations in electronics, software, photonics, imaging, motion control, automation, sensors, test, materials, manufacturing, mechanical, and mechatronics.

Briefs: Electronics & Computers
Watchdog Timer and Reset Control Circuit

A watchdog timer and reset control circuit has been designed for use with a microprocessor or microcontroller (hereafter "microcontroller" for short) that would otherwise lack the protection afforded...

Briefs: Physical Sciences
Continuous Electrolytic Generation of Hydrogen Peroxide

Electrolytic cells for the continuous generation of hydrogen peroxide in streams of water have been developed. Cells of this type could be incorporated into wastewater-treatment systems based on advanced oxidation processes that utilize hydroxyl radicals. In addition to...

The validation of computational-fluid-dynamics (CFD) software used for the design and analysis of turbomachinery has made it necessary to resolve measurement of the flow field more...

The Generic Spacecraft Analyst Assistant (GenSAA) computer program enables the rapid development of expert-system software for intelligent real-time monitoring and detection of...

Briefs: Mechanical & Fluid Systems
Digital PIV Measurements of Flow in a Centrifugal Compressor

A report describes experiments in which digital particle-image velocimetry (digital PIV) was used to measure the flow field in the diffuser of a high-speed centrifugal compressor. In digital PIV, a sheet of pulsed laser light illuminates a flow field seeded with small tracer particles,...

Briefs: Electronics & Computers
Inrush-Current-Control Circuit

The electronic circuit shown in the figure regulates the inrush current that arises upon initial application of voltage to capacitors. This inrush-current-control circuit is intended principally to be...

Briefs: Mechanical & Fluid Systems
Five Computer Codes for Analysis of Turbomachinery

A suite of five computational fluid dynamics (CFD) codes has been developed for analysis of flows in turbomachinery. Two of the codes are used to generate two-dimensional (2-D) or...

The P-Finite Element Integrated Thermal-Structural Program (PITS 2D) solves the equations for the combined effects of thermal expansion and elasticity in a two-dimensional or an...

Improved evaporators for loop heat pipes have been developed by incorporating bidisperse structures (in place of older monodisperse structures) into evaporator wicks. As explained in...

Briefs: Materials
Reducing Damage to Alumina Fibers in Metal-Matrix Composites

Coating alumina fibers with sputtered metal has been proposed as a means to enable the fibers to retain more strength when the fibers are incorporated into metal-matrix composites. If the alumina fibers could be made to retain more strength, then it would be possible to manufacture...

Briefs: Robotics, Automation & Control
Better Densification of Cryogenic Liquid Rocket Propellants

An improved system for densifying (by cooling) the liquid hydrogen and liquid oxygen used as propellants for the space shuttle has been proposed. These propellant liquids are...

Mathematical models to approximate the dynamics of aircraft are often generated by considering aircraft structures to be rigid bodies. These models may be unsuitable for evaluating...

A laser-diode-pumped thulium- and holmium-doped yttrium lithium fluoride (Tm,Ho:YLF) laser that operates at a single frequency and that can be both tuned and stabilized in frequency...

Briefs: Physical Sciences
Software for Probabilistic Thermal and Structural Analysis

NESTEM is a computer code that is a combination of a heat-transfer-analysis subprogram and a NASA in-house probabilistic-analysis code called "NESSUS" (for Numerical Evaluation of StochasticStructures Under Stress). NESTEM can be used to analyze a complex combustor thermal environment...

Briefs: Physical Sciences
Sun Shields for the Next Generation Space Telescope

A report discusses the design of inflatable Sun shields proposed for use in keeping the primary mirror of the Next generation Space Telescope (NGST) at a temperature "d60 K. The report summarizes a paper presented at the 33rd Intersociety Energy Conversion Engineering Conference in August 1998...

Briefs: Robotics, Automation & Control
Force-Reflecting, Finger-Position-Sensing Mechanism

An electromechanical device called the "Dexterous Master" (DM) is an exoskeletal mechanism that is worn on a human operator's hand for (1) measuring the positions and orientations of the...

Briefs: Photonics/Optics
Miniature Scanning Electron Microscope

A miniature scanning electron microscope (SEM) with a capability for x-ray microanalysis has been proposed. This SEM would be particularly suitable for analyzing samples of dust, soil, drill tailings,...

A continuing program of research is directed toward the development of crashworthy composite-material fuselages for small aircraft. These fuselages are required not only to withstand...

Briefs: Physical Sciences
SINDA/FLUINT Augmented To Represent Condensable Species

The Systems Improved Numerical Differencing Analyzer/Fluid Integrator (SINDA/FLUINT) software system has been upgraded by addition of a capability for simulating fluid mixtures that include condensable vapors. SINDA/FLUINT is the NASA standard software system for computational simulation...

Briefs: Electronics & Computers
Video-Based Active Alignment System

An optoelectronic system senses rotational and translational misalignment between two objects. The system might be used in such diverse applications as aligning construction equipment, mating parts of...

Briefs: Physical Sciences
Telescope/Camera Systems Based on Inflation-Deployed Optics

A report proposes the development of spaceborne telescope/camera systems that would be lightweight, relatively inexpensive alternatives to current systems based on glass mirrors. In a system of the proposed type, the primary reflector (typically a paraboloid several meters in diameter)...

Briefs: Physical Sciences
Two-Spacecraft Laser Tracking for Detecting Gravitational Waves

A paper proposes a method of mutual coherent laser tracking of two spacecraft for detecting gravitational radiation. Each spacecraft would transmit a laser beam to, and receive a similar laser beam from, the other spacecraft. Each spacecraft would also coherently transpond a laser...

The supercritical air mobility pack (SCAMP) is a prototype self-contained breathing apparatus designed for use in rescue and fire-fighting operations (see figure). The SCAMP is based on the...

Briefs: Photonics/Optics
Improved Optical Sensor for Monitoring Dissolved Oxygen

An optical sensor for measuring the partial pressure of dissolved oxygen in water is based on the effect of oxygen quenching on the fluorescence lifetime of an optically excited ruthenium complex immobilized in a recently developed polymer. In the operation of this sensor, the fluorescence...

The figure shows a first-phase prototype of a miniature, rugged long-wavelength infrared (LWIR) spectrometer that incorporates recent advances in the design and fabrication of microelectronic and...

Briefs: Electronics & Computers
Sensor Webs

Sensor webs are developmental collections of sensor pods that could be scattered over land or water areas or other regions of interest to gather data on spatial and temporal patterns of relatively slowly changing physical, chemical, or biological phenomena in those regions. Each sensor pod would be a node in a data-gathering/...

Briefs: Electronics & Computers
Microplasmic Coating Shows High Resistance to Wear, Heat and Corrosion

The process of anodizing, or controlled oxidation, of aluminum and aluminum alloys is more than seven decades old. The primary intent of anodizing aluminum and aluminum-alloy parts is to protect the highly reactive surface against corrosion in aqueous environments, such as...

Briefs: Electronics & Computers
Inflatable Reflectarray Antennas

A type of reflectarray antenna now undergoing development is based on the concept of a reflector membrane that is stretched flat by attaching it to an inflatable frame (see figure). Antennas of this type are...

Briefs: Software
Software Library for Parallel Adaptive Mesh Refinement

A software library has been developed for use in parallel adaptive refinement of unstructured (irregular) meshes and grids in parallel scientific and engineering computing. This library can be used in finite-difference, finite-volume, and finite-element application programs that use...

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