March 2004

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Briefs: Mechanical & Fluid Systems
A method of reducing the noise generated by a tilt-rotor aircraft during descent involves active control of the blade pitch of the rotors. This method is related to prior such noise-...
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Briefs: Mechanical & Fluid Systems
It has been proposed to incorporate piezoelectric vibrational actuators into the structural supports of solar photovoltaic panels, for the purpose of occasionally inducing vibrations in the panels...
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Briefs: Physical Sciences
A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The study is motivated by the fact that...
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Briefs: Unmanned Systems
In the summer of 2001, the Helios prototype solar-powered uninhabited aerial vehicle (UAV) [a lightweight, remotely piloted airplane] was deployed to the Pacific Missile Range Facility...
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Briefs: Information Technology
Autonomous environment-monitoring networks (AEMNs) are artificial neural networks that are specialized for recognizing familiarity and, conversely, novelty. Like a biological neural network, an AEMN...
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Briefs: Information Technology
An improved method of computing a discrete approximation of the Laplacian of a Gaussian convolution of an image has been devised. The primary advantage of the method is that without...
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Briefs: Information Technology
Utilizing Expert Knowledge in Estimating Future STS Costs
A method of estimating the costs of future space transportation systems (STSs) involves classical activity-based cost (ABC) modeling combined with systematic utilization of the knowledge and opinions of experts to extend the process-flow knowledge of existing systems to systems that involve...
Briefs: Photonics/Optics
Advances in the development and manufacturing of photonic processors have reached a critical stage where their mass applications are becoming commercially viable. LNL...
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Briefs: Information Technology
More About the Phase-Synchroized Enhancement Method
A report presents further details regarding the subject matter of "Phase-Synchronized Enhancement Method for Engine Diagnostics" (MFS-26435), NASA Tech Briefs, Vol. 22, No. 1 (January 1998), page 54. To recapitulate: The phase-synchronized enhancement method (PSEM) involves the digital resampling...
Briefs: Photonics/Optics
A versatile and simple approach to the design and fabrication of curved-focal-plane arrays of silicon-based photodetectors is being developed. This approach is an alternative to...
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Briefs: Photonics/Optics
Under a DARPA program known as Steered Agile Beams (STAB), novel liquid-crystal devices are being developed by Rockwell Scientific Company (RSC) to...
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Briefs: Mechanical & Fluid Systems
Strain-Gauge Measurement of Weight of Fluid in a Tank
A method of determining the amount of fluid in a tank is based on measurement of strains induced in tank supports by the weight of the fluid. Unlike most prior methods, this method is nonintrusive: there is no need to insert instrumentation in the tank and, hence, no need to run wires, cables,...
Briefs: Manufacturing & Prototyping
A procedure now under development is intended to enable the precise alignment of sheet arrays of microscopic lenses with the end faces of a coherent bundle of as many as 1,000...
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Briefs: Medical
When a dog or cat breaks a bone, veterinarians often mend the fracture with a combination of stabilization devices called intra-medullary (IM) pins and external skeletal...
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Briefs: Mechanical & Fluid Systems
An advanced docking system is undergoing development to enable softer, safer docking than was possible when using prior docking systems. This system is intended for original use in docking...
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Briefs: Mechanical & Fluid Systems
Columnar-vortex generators (CVG) have been proposed as means to increase the safety of takeoffs and landings of aircraft on aircraft or helicopter carriers and other ships at sea....
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Briefs: Manufacturing & Prototyping
Automatic Control of Arc Process for Making Carbon Nanotubes
An automatic-control system has been devised for a process in which carbon nanotubes are produced in an arc between a catalyst-filled carbon anode and a graphite cathode. The control system includes a motor-driven screw that adjusts the distance between the electrodes. The system also...
Briefs: Materials
Experiments have shown that composites of a silicone elastomer with single-wall carbon nanotubes (SWNTs) are significantly stronger and stiffer than is the unfilled elastomer. The large...
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Briefs: Materials
Study of Rapid-Regression Liquefying Hybrid Rocket Fuels
A report describes experiments directed toward the development of paraffin-based hybrid rocket fuels that burn at regression rates greater than those of conventional hybrid rocket fuels like hydroxyl-terminated butadiene. The basic approach followed in this development is to use materials...
Briefs: Electronics & Computers
Advanced Signal Conditioners for Data-Acquisition Systems
Signal conditioners embodying advanced concepts in analog and digital electronic circuitry and software have been developed for use in data-acquisition systems that are required to be compact and lightweight, to utilize electric energy efficiently, and to operate with high reliability, high...
Briefs: Electronics & Computers
A multiplexer/demultiplexer system has been developed to enable the transmission, over a single channel, of four data streams generated by a variety of sources at different (including variable) bit rates. In the...
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Briefs: Electronics & Computers
Architectures have been proposed for the design of frequency-domain least-mean-square complex equalizers that would be integral parts of parallel-processing digital receivers of...
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Briefs: Electronics & Computers
AIN-Based Packaging for SiC High-Temperature Electronics
Packaging made primarily of aluminum nitride has been developed to enclose silicon carbide-based integrated circuits (ICs), including circuits containing SiC-based power diodes, that are capable of operation under conditions more severe than can be withstood by silicon-based integrated...
Briefs: Electronics & Computers
Historically, the price of non-commercial hardware has been astronomical due to the engineering required for it to perform specific functions and to operate reliably in harsh conditions, with ambient...
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Briefs: Software
Readout of DSN Monitor Data
DSN Monitor Data Reader is a computer program that, as its name suggests, reads file of monitor data from the Deep Space Network (DSN). The monitor data constitute information on the status and performance of tracking, telemetry, command, and pointing equipment at the DSN antennas. The DSN has recently introduced a new,...
Briefs: Software
Viewing ISS Data in Real Time via the Internet
EZStream is a computer program that enables authorized users at diverse terrestrial locations to view, in real time, data generated by scientific payloads aboard the International Space Station (ISS). The only computation/ communication resource needed for use of EZStream is a computer equipped with...
Briefs: Software
Software for Optimizing Quality Assurance of Other Software
Software assurance is the planned and systematic set of activities that ensures that software processes and products conform to requirements, standards, and procedures. Examples of such activities are the following: code inspections, unit tests, design reviews, performance analyses,...
Briefs: Software
The TechSat 21 Autonomous Sciencecraft Experiment
Software has been developed to perform a number of functions essential to autonomous operation in the Autonomous Sciencecraft Experiment (ASE), which is scheduled to be demonstrated aboard a constellation of three spacecraft, denoted TechSat 21, to be launched by the Air Force into orbit around the...
Briefs: Software
Software for Analyzing Laminar-to-Turbulent Flow Transitions
Langley Stability and Transition Analysis Codes (LASTRAC) is a set of engineering software tools developed with the C++ language and modern software technologies for use in analyzing transition from laminar to turbulent flows. LASTRAC is a product of on-going NASA Langley research...
Briefs: Physical Sciences
Solution-Assisted Optical Contacting
A modified version of a conventional optical-contact procedure has been found to facilitate alignment of optical components. The optical-contact procedure (called simply "optical contacting" in the art) is a standard means of bonding two highly polished and cleaned glass optical components without using epoxies...

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