Special Coverage

Distributed Propulsion Concepts and Superparamagnetic Energy Harvesting Hummingbird Engine
Aerofoam
Wet Active Chevron Nozzle for Controllable Jet Noise Reduction
Magnetic Relief Valve
Locking Mechanism for a Flexible Composite Hinge
Active Aircraft Pylon Noise Control System
Unmanned Aerial Systems Traffic Management
Method of Bonding Dissimilar Materials
Sonar Inspection Robot System
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Vision System Provides Real-Time Guidance for Unmanned Docking Operations

TriDAR vision system Neptec Design Group Ottawa, ON, Canada 613-599-7602 www.neptec.com NASA is conducting a Detailed Test Objective (DTO) with Neptec’s TriDAR vision system for use in unmanned docking operations. The vision system provides real-time visual guidance for navigation, rendezvous, and docking procedures, and is expected to play a critical role in future space exploration missions.

Posted in: Application Briefs

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Low-Cost Liquid Metal Cooling for High-Thermal-Density Electronics

Liquid metal has been used as a coolant for system-level thermal management for decades in nuclear reactors. The reason is its efficiency — liquid metal can have an effective thermal conductivity 10 to 100 times the thermal conductivity of copper. However, cost and long-term reliability of liquid metal cooling approaches have previously precluded its widespread use for cooling of high-thermal-density electronics. Rockwell Collins has developed a liquid metal cooling technology that solves these issues.

Posted in: Techs for License

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Needle-Free Injection System Using Pyrotechnical Propulsion

PYROFAST is a needle-free injection system with pyrotechnical gas propulsion that provides accurate and comfortable drug delivery through the skin for intra-dermal, subcutaneous, and intra-muscular injections of liquid and solid (lyophilized) drugs. The needle-free injection occurs within 40 msec; a very fine, high-pressure jet stream of liquid medication painlessly penetrates the skin, depositing medication in the tissue beneath. Needle-free injection reduces skin trauma and pain, and leads to better patient compliance by eliminating the patient’s phobia of needles. PYROFAST technology does not cause bleeding, which is often experienced with a needle injection, thus eliminating the risk of transmission of bloodborne diseases. The gas generator of the PYROFAST system uses a chemical substance that, after activation, generates a gas to create a well-defined and reliable pressure profile suitable for the injection of liquid drugs. The gas puts pressure on a plunger in the injection ampoule of the Medication Unit, which pushes the liquid through the orifice of the nozzle. Get the complete report on this technology at: www.techbriefs.com/tow/200911b.html Email: nasatech@yet2.com Phone: 781-972-0600

Posted in: Techs for License

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Hardware Implementation of a Bilateral Subtraction Filter

Modules like this one are necessary for real-time stereoscopic machine vision. A bilateral subtraction filter has been implemented as a hardware module in the form of a field-programmable gate array (FPGA). In general, a bilateral subtraction filter is a key subsystem of a high-quality stereoscopic machine vision system that utilizes images that are large and/or dense. Bilateral subtraction filters have been implemented in software on general-purpose computers, but the processing speeds attainable in this way — even on computers containing the fastest processors — are insufficient for real-time applications. The present FPGA bilateral subtraction filter is intended to accelerate processing to real-time speed and to be a prototype of a link in a stereoscopic-machine-vision processing chain, now under development, that would process large and/or dense images in real time and would be implemented in an FPGA.

Posted in: Briefs, TSP, Semiconductors & ICs

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Lattice-Matched Semiconductor Layers on Single Crystalline Sapphire Substrate

Rhombohedrally grown lattice-matched semiconductor alloys can be used in photovoltaic solar cells and photon detectors. SiGe is an important semiconductor alloy for high-speed field effect transistors (FETs), high-temperature thermoelectric devices, photovoltaic solar cells, and photon detectors. The growth of SiGe layer is difficult because SiGe alloys have different lattice constants from those of the common Si wafers, which leads to a high density of defects, including dislocations, micro-twins, cracks, and delaminations.

Posted in: Briefs, TSP, Semiconductors & ICs

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Discrete Fourier Transform Analysis in a Complex Vector Space

Alternative computational strategies for the Discrete Fourier Transform (DFT) have been developed using analysis of geometric manifolds. This approach provides a general framework for performing DFT calculations, and suggests a more efficient implementation of the DFT for applications using iterative transform methods, particularly phase retrieval. The DFT can thus be implemented using fewer operations when compared to the usual DFT counterpart. The software decreases the run time of the DFT in certain applications such as phase retrieval that iteratively call the DFT function. The algorithm exploits a special computational approach based on analysis of the DFT as a transformation in a complex vector space. As such, this approach has the potential to realize a DFT computation that approaches N operations versus Nlog(N) operations for the equivalent Fast Fourier Transform (FFT) calculation.

Posted in: Briefs, Manufacturing & Prototyping

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Self-Assembling, Flexible, Pre-Ceramic Composite Preforms

Pliable, unfired preforms deploy in-situ to save fuel and weight costs. In this innovation, light weight, high temperature, compact aerospace structures with increased design options are made possible by using self-assembling, flexible, pre-ceramic composite materials. These materials are comprised of either ceramic or carbon fiber performs, which are infiltrated with polymer precursors that convert to ceramics upon thermal exposure. The preform architecture can vary from chopped fibers formed into blankets or felt, to continuous fibers formed into a variety of 2D or 3D weaves or braids. The matrix material can also vary considerably. For demonstration purposes, a 2D carbon weave was infiltrated with a SiC polymer precursor. The green or unfired material is fabricated into its final shape while it is still pliable. It is then folded or rolled into a much more compact shape, which will occupy a smaller space. With this approach, the part remains as one continuous piece, rather than being fabricated as multiple sections, which would require numerous seals for eventual component use. The infiltrated preform can then be deployed in-situ. The component can be assembled into its final shape by taking advantage of the elasticity of the material, which permits the structure to unfold and spring into its final form under its own stored energy. The pre-ceramic composites are converted to ceramics and rigidized immediately after deployment.

Posted in: Briefs, TSP, Manufacturing & Prototyping

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