News

'Active' Surfaces Control How Particles Move

Researchers at MIT and in Saudi Arabia have developed a new way of making surfaces that can actively control how fluids or particles move across them. The work might enable new kinds of biomedical or microfluidic devices, or solar panels that could automatically clean themselves of dust and grit.The system makes use of a microtextured surface, with bumps or ridges just a few micrometers across, that is then impregnated with a fluid that can be manipulated — for example, an oil infused with tiny magnetic particles, or ferrofluid, which can be pushed and pulled by applying a magnetic field to the surface. When droplets of water or tiny particles are placed on the surface, a thin coating of the fluid covers them, forming a magnetic cloak.The thin magnetized cloak can then actually pull the droplet or particle along as the layer itself is drawn magnetically across the surface. Tiny ferromagnetic particles, approximately 10 nanometers in diameter, in the ferrofluid could allow precision control when it’s needed — such as in a microfluidic device used to test biological or chemical samples by mixing them with a variety of reagents. Unlike the fixed channels of conventional microfluidics, such surfaces could have “virtual” channels that could be reconfigured at will.The new approach could be useful for a range of applications: For example, solar panels and the mirrors used in solar-concentrating systems can quickly lose a significant percentage of their efficiency when dust, moisture, or other materials accumulate on their surfaces. But if coated with such an active surface material, a brief magnetic pulse could be used to sweep the material away.Source Also: Read more Materials tech briefs.

Posted in: Motion Control, Fluid Handling, Medical, Drug Delivery & Fluid Handling, Solar Power, Renewable Energy, Energy, News

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Army to Get New IED Detector Technology

Detecting improvised explosive devices in Afghanistan requires constant, intensive monitoring using rugged equipment. When Sandia researchers first demonstrated a modified miniature synthetic aperture radar (MiniSAR) system to do just that, some experts didn't believe it. But those early doubts are long gone. Sandia's Copperhead — a highly modified MiniSAR system mounted on unmanned aerial vehicles (UAVs) — has been uncovering IEDs in Afghanistan and Iraq since 2009. Now, according to senior manager Jim Hudgens, Sandia is transferring the technology to the U.S. Army to support combat military personnel.

Posted in: Electronics & Computers, Imaging, Sensors, Detectors, RF & Microwave Electronics, Antennas, Data Acquisition, Defense, News

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Tiny Laser Sensor Heightens Bomb Detection Sensitivity

A team of researchers led by Xiang Zhang, UC Berkeley professor of mechanical engineering, has found a way to dramatically increase the sensitivity of a light-based plasmon sensor to detect incredibly minute concentrations of explosives. The researchers noted that the sensor could potentially be used to sniff out a hard-to-detect explosive popular among terrorists. The engineers put the sensor to the test with various explosives — 2,4- dinitrotoluene (DNT), ammonium nitrate and nitrobenzene — and found that the device successfully detected the airborne chemicals at concentrations of 0.67 parts per billion, 0.4 parts per billion and 7.2 parts per million, respectively. One part per billion would be akin to a blade of grass on a football field. They noted that these results are much more sensitive than those published to date for other optical sensors.

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Army Develops First-of-Its Kind Phase-Coherent Fiber Laser Array System

The U.S. Army Research Laboratory's Computational and Information Science Directorate's Intelligent Optics Team, and partners, recently developed, engineered, demonstrated and delivered the world's first known working Adaptive Phase Coherent Fiber Laser Array system, which will better enable soldiers' directed energy weapons and laser communication systems on the battlefield. The development of the system spurred from a collaborative agreement between U.S. Army Research Laboratory (ARL), the Defense Advanced Research Projects Agency (DARPA), the Massachusetts Institute of Technology Lincoln Labs, Optonicus and various academic partners.

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NASA 3D-Printing Process Transitions from Metal to Metal

Researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, are implementing a 3D-printing process that transitions from one metal or alloy to another in a single object. "You can have a continuous transition from alloy to alloy to alloy, and you can study a wide range of potential alloys," said R. Peter Dillon, a technologist at JPL. "We think it's going to change materials research in the future."Although gradient alloys have been created in the past in research and development settings, this is the first time these composite materials have been used in making objects, such as a mount for a mirror, said John Paul Borgonia, a JPL mechanical engineer.In their new technique, Hofmann and his colleagues deposit layers of metal on a rotating rod, thus transitioning metals from the inside out, rather than adding layers from bottom to top, as in the more traditional 3-D printing technique. A laser melts metal powder to create the layers. Future space missions may incorporate parts made with this technique.SourceAlso: Learn about a Shape-Memory-Alloy-Based Launch Lock.

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Vision-Correcting Display Replaces Reading Glasses

UC Berkeley computer and vision scientists are developing computer algorithms to compensate for an individual’s visual impairment. The researchers have created vision-correcting displays that enable users to see text and images clearly without wearing eyeglasses or contact lenses.The algorithm, which was developed at UC Berkeley, works by adjusting the intensity of each direction of light that emanates from a single pixel in an image based upon a user’s specific visual impairment. In a process called deconvolution, the light passes through the pinhole array in such a way that the user will perceive a sharp image.The technology could potentially help hundreds of millions of people who currently need corrective lenses to use their smartphones, tablets and computers. More importantly, the displays could one day aid people with more complex visual problems, known as high order aberrations, which cannot be corrected by eyeglasses, said Brian Barsky, UC Berkeley professor of computer science and vision science, and affiliate professor of optometry.SourceAlso: Learn about Strobing to Mitigate Vibration for Display Legibility.

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Researchers Build 'Invisible' Materials with Light

Metamaterials have a wide range of potential applications, including sensing and improving military stealth technology. Before cloaking devices can become reality on a larger scale, however, researchers must determine how to make the right materials at the nanoscale. Using light is now shown to be an enormous help in such nano-construction. A new technique uses light like a needle to thread long chains of particles. The development could help bring sci-fi concepts, such as cloaking devices, one step closer to reality.The technique developed by the University of Cambridge team involves using unfocused laser light as billions of needles, stitching gold nanoparticles together into long strings, directly in water for the first time. The strings can then be stacked into layers one on top of the other, similar to Lego bricks. The method makes it possible to produce materials in much higher quantities than can be made through current techniques. SourceAlso: See other Sensors tech briefs.

Posted in: Photonics, Lasers & Laser Systems, Materials, Sensors, Nanotechnology, Defense, News

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