Tech Briefs

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.

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Briefs: Physical Sciences
Update on Area Production in Mixing of Supercritical Fluids
The paper “Turbulence and Area Production in Binary-Species, Super- critical Transitional Mixing Layers” presents a more recent account of the research sum- marized at an earlier stage in “Area Production in Super- critical, Transitional Mixing Layers” (NPO-30425), NASA Tech...
Briefs: Physical Sciences
Dyakonov-Perel Effect on Spin Dephasing in n-Type GaAs
A paper presents a study of the contribution of the Dyakonov-Perel (DP) effect to spin dephasing in electron-donor-doped bulk GaAs in the presence of an applied steady, moderate magnetic field perpendicular to the growth axis of the GaAs crystal. (The DP effect is an electron-wave-...
Briefs: Mechanical & Fluid Systems
Quasi-Sun-Pointing of Spacecraft Using Radiation Pressure
A report proposes a method of utilizing solar-radiation pressure to keep the axis of rotation of a small spin-stabilized spacecraft pointed approximately (typically, within an angle of 10° to 20°) toward the Sun. Axisymmetry is not required. Simple tilted planar vanes would be attached to...
Briefs: Mechanical & Fluid Systems
Cable-Dispensing Cart
A versatile cable- dispensing cart can support as many as a few dozen reels of cable, wire, and/or rope. The cart can be adjusted to accommodate reels of various diameters and widths, and can be expanded, contracted, or otherwise reconfigured by use of easily installable and removable parts that can be carried onboard. Among...
Briefs: Mechanical & Fluid Systems
Device for Locking a Control Knob
A simple, effective, easy-to-use device locks a control knob in a set position. In the initial application for which this device was conceived, the control knob to be locked is that of a needle valve. Previously, in that application, it was necessary for one technician to hold the knob to keep the valve at the...
Briefs: Mechanical & Fluid Systems
Three techniques have been proposed to prolong the intervals of time available for microgravity experiments aboard airplanes flown along parabolic trajectories. Typically, a pilot strives to...
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Briefs: Information Technology
An improved method of analysis of coverage of areas of the Earth by a constellation of radio-communication or scientific-observation satellites has been developed. This method is intended...
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Briefs: Information Technology
Update on EMD and Hilbert-Spectra Analysis of Time Series
U.S. Patent 6,381,559 presents further information about the method described in "Analyzing Time Series Using EMD and Hilbert Spectra" (GSC-13817), NASA Tech Briefs, Vol. 24, No. 10 (October 2000), page 63. To recapitulate: The method is especially well suited for analyzing time-series data...
Briefs: Electronics & Computers
Figure 1 shows a three-stage monolithic microwave integrated circuit (MMIC) power amplifier that features high-electron-mobility transistors (HEMTs) as gain elements. This amplifier is designed to...
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Briefs: Electronics & Computers
An apparatus that is extremely effective in dispensing a wide range of droplets has been developed. This droplet dispenser is unique in that it utilizes a droplet bias voltage, as well as an ionization pulse, to...
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Briefs: Electronics & Computers
Network Extender for MIL-STD-1553 Bus
An extender system for MIL-STD-1553 buses transparently couples bus components at multiple developer sites. The bus network extender is a relatively inexpensive system that minimizes the time and cost of integration of avionic systems by providing a convenient mechanism for early testing without the need to...
Briefs: Electronics & Computers
Some prototype parts of a digital beam-forming (DBF) receiver that would operate at multigigahertz carrier frequencies have been developed. The beam-forming algorithm in a DBF...
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Briefs: Electronics & Computers
The Real-Time Interferometer Control Systems Testbed (RICST) timing board is a VersaModule Eurocard (VME)-based board that can generate up to 16 simultaneous, phase-locked timing signals at a rate defined...
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Briefs: Software
Numerical Modeling of Nanoelectronic Devices
Nanoelectronic Modeling 3-D (NEMO 3-D) is a computer program for numerical modeling of the electronic structure properties of a semiconductor device that is embodied in a crystal containing as many as 16 million atoms in an arbitrary configuration and that has overall dimensions of the order of tens of...
Briefs: Electronics & Computers
A proposed tracking receiver system containing three suitably positioned antenna elements and special signal-processing equipment would determine the direction of incidence of a...
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Briefs: Photonics/Optics
Optical assemblies are used in an extensive range of technical applications to deliver a laser beam of a certain size, quality, and intensity to a region of space. While different...
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Briefs: Photonics/Optics
Piezoelectric diffraction-based optoelectronic devices have been invented to satisfy requirements for switching signals quickly among alternative optical paths in optical communication networks....
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Briefs: Photonics/Optics
A design concept has been proposed for an optomechanical apparatus that would implement a variable optical delay line with a fixed angle between its input and output light beams. The apparatus...
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Briefs: Photonics/Optics
Mode-locked lasers of a proposed type would incorporate features of the design and operation of previously demonstrated miniature electro-optical modulators and erbium-doped glass lasers that contain...
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Briefs: Photonics/Optics
A method of observing the interdiffusion of a pair of miscible liquids is based on the use of a common-path interferometer (CPI) to measure the spatially varying gradient of the...
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Briefs: Software
Computer Program Recognizes Patterns in Time-Series Data
A computer program recognizes selected patterns in time-series data like digitized samples of seismic or electrophysiological signals. The program implements an artificial neural network (ANN) and a set of N clocks for the purpose of determining whether N or more instances of a certain...
Briefs: Mechanical & Fluid Systems
A compact, pneu- matically actuated filter shuttle has been invented to enable alternating imaging of a wind-tunnel model in two different spectral bands characteristic of the pressure and...
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Briefs: Software
Software for Planning Scientific Activities on Mars
Mixed-Initiative Activity Plan Generator (MAPGEN) is a ground-based computer program for planning and scheduling the scientific activities of instrumented exploratory robotic vehicles, within the limitations of available resources onboard the vehicle. MAPGEN is a combination of two prior software...
Briefs: Software
Software for Training in Pre-College Mathematics
The Intelligent Math Tutor (IMT) is a computer program for training students in pre-college and college-level mathe- matics courses, including fundamentals, intermediate algebra, college algebra, and trigonometry. The IMT can be executed on a server computer for access by students via the Internet;...
Briefs: Software
Software for Simulating a Complex Robot
RoboSim (Robot Simulation) is a computer program that simulates the poses and motions of the Robonaut — a developmental anthropomorphic robot that has a complex system of joints with 43 degrees of freedom and multiple modes of operation and control. RoboSim performs a full kinematic simulation of all...
Briefs: Software
Software Helps Retrieve Information Relevant to the User
The Adaptive Indexing and Retrieval Agent (ARNIE) is a code library, designed to be used by an application program, that assists human users in retrieving desired information in a hypertext setting. Using ARNIE, the program implements a comp- utational model for interactively learning what...
Briefs: Electronics & Computers
The new high-speed interconnect standards will dramatically change the way computer and communication systems are designed. Switch- based systems will be the winners in new high-performance designs,...
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Briefs: Software
Software for Diagnosis of Multiple Coordinated Spacecraft
Distributed Real-Time Model-Based Diagnosis (DRMD) is a computer program for diagnosing faults in multiple spacecraft cooperating in a specific task (e.g., flying in formation to constitute an inter- ferometer). DRMD takes advantage of both (1) the superiority of model-based software for...
Briefs: Software
Software for Refining or Coarsening Computational Grids
A computer program performs calculations for refinement or coarsening of computational grids of the type called “structured” (signifying that they are geo- metrically regular and/or are specified by relatively simple algebraic expressions). This program is designed to facilitate analysis...

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