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Self-Healing Wire Insulation
Thermomechanical Methodology for Stabilizing Shape Memory Alloy (SMA) Response
Space Optical Communications Using Laser Beams
High Field Superconducting Magnets
Active Response Gravity Offload and Method
Strat-X
Sonar Inspection Robot System
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Method of Performing Computational Aeroelastic Analyses

This technology can be used for dynamic behavioral models of large buildings, bridges, dams, and towers. NASA’s Langley Research Center has developed unsteady aerodynamic Reduced-Order Models (ROMs) that significantly improve computational efficiency compared to traditional analyses of aeroelastic and other complex and unsteady systems. Traditional methods rely on the repetitive use of aeroelastic computational fluid dynamics (CFD) codes, and the iteration between the structural and nonlinear aerodynamic models of the aeroelastic CFD code for predicting the aeroelastic response of flight vehicles is very time-consuming and computationally expensive. The new ROMs are quite different from the traditional aeroelastic analysis tools, and enable the computational aeroelastic analysis of flight vehicles at a fraction of the time and cost.

Posted in: Briefs, Software

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Fourier Transform Spectrometer Performance Modeling

This software models the performance of a Fourier transform spectrometer (FTS). More specifically, it is able to add a number of noise/error sources to the interferogram and transform the errors back to the spectral domain.

Posted in: Briefs, Software

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Mesh Adaptation Module for Cartesian Meshes with Embedded Boundaries

Future applications include rapid prototyping, computer-based imaging and visualization, and semiconductor device modeling. This work extends the mesh generation capability of NASA’s Cart3D flow simulation software package to permit cell-by-cell mesh enrichment. Cart3D allows users to perform automated Computational Fluid Dynamics (CFD) analysis on a complex geometry. It includes utilities for geometry import, surface modeling and intersection, mesh generation, flow simulation, and post-processing of results. Geometry enters into Cart3D in the form of surface triangulations that may be generated from within Computer-Aided Design (CAD) packages, from legacy surface triangulations, or from structured surface grids. Cart3D uses adaptively refined Cartesian grids to discretize the space surrounding geometry, and cuts the geometry out of the set of cut-cells that actually intersects the surface triangulation.

Posted in: Briefs, Software

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How to Manage Heat in Modular, COTS Enclosures

As components shrink, embedded systems have made their way into smaller and more mobile applications. Systems need to withstand more intense vibration, shock and EMI parameters and still function effectively. All of this affects the ruggedization of enclosures.

Posted in: White Papers, Defense, Electronics, Manufacturing & Prototyping

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New Phosphors and Next-Generation Lighting

Researchers from KU Leuven in Belgium, the University of Strasbourg, and CNRS have discovered a new phosphor that could make next-generation fluorescent and LED lighting even cheaper and more efficient. The team used highly luminescent clusters of silver atoms and the porous framework of minerals known as zeolites. Silver clusters consist of just a few silver atoms and have remarkable optical properties. However, current applications are limited, because the clusters tend to aggregate into larger particles, thus losing the interesting optical properties. But researchers have found a way to keep the silver clusters apart by inserting them into the porous framework of zeolites. The result: stable silver clusters that maintain their unique optical properties. Zeolites are minerals that are either found in nature or produced synthetically on an industrial scale. The minerals have a very rigid and well-defined framework of small molecular-sized channels, pores, and cages. They're commonly used in domestic and industrial applications such as washing detergent and water treatment. Using advanced techniques, researchers found that the structural, electronic, and optical properties of the zeolites were strongly influenced by the silver clusters. That's how they discovered that the shape of the silver clusters is essential to obtain the right fluorescence properties. Professor Johan Hofkens explains: "Clusters of silver atoms can assemble into different shapes, including a line or a pyramid. This pyramid shape is what we need to obtain the best fluorescence properties. Heating up the silver ions in the zeolite framework makes them adopt this shape. Because they are 'trapped', as it were, in the cages of the zeolites, they can only form a pyramid with up to four silver atoms. That is exactly the shape and size in which the silver cluster emits the largest amount of fluorescent light, with an efficiency close to 100%." These findings have great potential for the development of next-generation fluorescent and LED lighting and for biological imaging. After all, the new phosphors not only emit a large amount of light, they are also cheap to produce.

Posted in: News

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Molecular Switch for Controlling Color

A collaboration of researchers from Kumamoto, Yamaguchi, and Osaka Universities in Japan have discovered a new method of drastically changing the color and fluorescence of a particular compound using only oxygen (O2) and hydrogen (H2) gases. The fully reversible reaction is environmentally friendly since it produces only water as a byproduct. Rather than using electrical or photo energy, the discovery uses energy from the gases themselves, which is expected to become a future trend, to switch the color and fluorescence properties. The technique could be used as a detection sensor for hydrogen or oxygen gases as well as for property controls of organic semiconductors and organic light emitting diodes (OLEDs). Polyaromatic compounds (PACs) are widely used in fluorescent materials, semiconductor materials, organic EL devices, and organic solar-cell devices. The research performed at Kumamoto University focused on using energy from gases"We tried to determine the most attractive compounds that could freely and dramatically change the optical properties of the PAC with a redox reaction," said Associate Professor Hayato Ishikawa from Kumamoto University. "Specifically, we introduced an orthoquinone moiety to the PAC that possessed the most ideal switching properties under a redox reaction with hydrogen and oxygen gases." To determine the candidates with the best switching properties, researchers screened several orthoquinone-containing aromatic compounds in a computational study. The ideal molecules clearly showed switching between fluorescence emission and quenching, and between a colored and colorless state. Picene-13, 14-dione was nominated as the most promising candidate from the computational analysis. The researchers then developed an original protocol to efficiently synthesize the compound from commercially available petroleum raw materials. The key steps for the synthesis were the transition metal-catalyzed coupling reaction and the ring construction reaction by an organocatalyst. This synthetic methodology is also applicable to the synthesis of various other similar compounds or derivatives. A palladium nanoparticle catalyst was added to the synthesized picene-13, 14-dione and then H2 gas was bubbled into the solution. As predicted by the computational study, a dramatic change in color and fluorescence of the solution was observed; its color and fluorescence changed from yellow to colorless, and from non-fluorescent to blue fluorescent respectively. The subsequent reverse oxidation proceeded smoothly when H2 gas was exchanged for O2 gas, and the solution reverted back to its original state. "When we performed a detailed analysis, it was revealed that the resultant changes in color and fluorescence were caused by two different molecular states. The prediction of these states, and our ideas about this phenomenon, were strongly supported by both the computational analysis and the experimental results," said Ishikawa. "This molecular switching technology of an aromatic compound using an orthoquinone moiety is a new insight that appears to have been reported first by our research team."

Posted in: News

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Intelligent Machine Tool Prototype

A research group led by Professor Shirase Keiichi of the Kobe University Graduate School of Engineering has developed a prototype machine tool that can manufacture metal components and operates like a 3D printer. This development could speed up the manufacture of custom-made products such as dental implants and artificial bones, potentially shortening production times and reducing costs. The machine tool prototype is a product of Kobe University's ongoing research into intelligent machine tools. This is one of three Kobe University projects in the category of innovative design and manufacturing technologies selected for the Strategic Innovation Promotion Program (SIP), a project headed by the Japanese Cabinet Office's Council for Science, Technology and Innovation. Currently most machine tools for metal cutting follow instructions from a program that is manually prepared in advance. However, in addition to the huge amount of labor required to create each program, this method has potential issues, as the machines cannot make adjustments to the machining process or respond to unforeseen problems. Metal components can also be shaped using metal 3D printers, but this too has disadvantages including the expense of the the metal powder used as a raw material. The prototype created by Professor Shirase's team marks a shift from providing machine tools with instructions to entrusting machine tools with the machining operation. If you prepare a 3D model and a material model of the component, the machine tool itself will determine the optimum machining process using a database of machining information and cutting conditions. This development could potentially pave the way for intelligent manufacturing systems, reduced costs, and faster production times.

Posted in: News

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