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Researchers Craft Vivid Colors on Ultra-Thin Coatings

A new coating exploits interference effects in thin films, creating a range of vivid colors. The new technique coats a metallic object with an extremely thin layer of semiconductor, just a few nanometers thick. Although the semiconductor is a steely gray color, the object ends up shining in vibrant hues.The ultrathin coatings could be applied to essentially any rough or flexible material, from wearable fabrics to stretchable electronics.A machine called an electron-beam evaporator applies the gold and germanium coating. The paper sample is sealed inside the machine's chamber, and a pump sucks out the air until the pressure drops to a staggering 10-6 Torr (a billionth of an atmosphere). A stream of electrons strikes a piece of gold held in a carbon crucible, and the metal vaporizes, traveling upward through the vacuum until it hits the paper. Repeating the process, a second layer is added. A little more or a little less germanium makes the difference between indigo and crimson."This is a way of coloring something with a very thin layer of material, said Mikhail Kats, postdoctoral researcher at the Harvard School of Engineering and Applied Sciences, "so in principle, if it's a metal to begin with, you can just use 10 nanometers to color it, and if it's not, you can deposit a metal that's 30 nm thick and then another 10 nm. That's a lot thinner than a conventional paint coating that might be between a micron and 10 microns thick.” SourceAlso: Read about other Materials and Coatings.

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NASA Tests Gecko Grippers in Microgravity

Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, are working on adhesive gripping tools that could grapple objects such as orbital debris or defunct satellites that would otherwise be hard to handle.The gecko gripper project was selected for a test flight through the Flight Opportunities Program of NASA's Space Technology Mission Directorate. As a test, researchers used the grippers in brief periods of weightlessness aboard NASA's C-9B parabolic flight aircraft in August.The gripping system developed by Parness and colleagues was inspired by geckos, lizards that cling to walls with ease. Geckos' feet have branching arrays of tiny hairs, the smallest of which are hundreds of times thinner than a human hair. This system of hairs can conform to a rough surface without a lot of force. Although researchers cannot make a perfect replica of the gecko foot, they have put "hair" structures on the adhesive pads of the grippers.The synthetic hairs, also called stalks, are wedge-shaped and have a slanted, mushroom-shaped cap. When the gripping pad lightly touches part of an object, only the very tips of the hairs make contact with that surface.SourceAlso: Learn about Microgravity Storage Vessels for Cohesive Regolith.

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Unique Method for Orifice Production

To produce accurate, repeatable orifices, all the variables that might influence the Cd Value (Coefficient of Discharge) must be controlled during production. This includes the orifice hole length, edges, surface finishes, roundness and the elimination of all tool marks, burrs, ragged edges and irregularities. If any one of these areas is not perfectly managed, the orifice flow rates will vary from piece to piece thereby making it impossible to predict flow with any accuracy.

Posted in: Mechanics, White Papers, White Papers

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Software Defined Radio Handbook

Software Defined Radio has revolutionized electronic systems for a variety of applications that include communications, data acquisition and signal processing. Recently updated, this handbook shows how DDCs (Digital Downconverters), the fundamental building block of software radio, can replace legacy analog receiver designs while offering significant performance, density, and cost benefits.

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High-Speed A/Ds for Real-Time Systems

Recently updated, this handbook reviews the markets and technology for A/Ds with sampling frequencies higher than 100 MHz; it discusses sampling and filtering techniques and new FPGA technology for A/Ds; typical high speed A/D products are presented, along with some high-speed data acquisition applications.

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Putting FPGAs to Work in Software Radio Systems

Recently updated, this handbook reviews the latest FPGA technology and how it can be put to use in software radio systems. FPGAs offer significant advantages for implementing software radio functions such as digital downconverters and upconverters. These advantages include design flexibility, higher precision processing, lower power, and lower cost.

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High-Speed, Real-Time Recording Systems Handbook

Recently updated, this handbook reviews some of the techniques and features that are widely desired in a high-speed, real-time recording system. Among others, these include the use of a non-proprietary file system, the use of a client-server architecture, and the presence of a user-friendly API (Application Programming Interface) for integrating the recorder into a larger system.

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