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New Compounds Developed to Manufacture Tunable OLED Devices

Researchers have developed new organic compounds characterized by higher modularity, stability, and efficiency that could be applicable for use in electronics or lighting. A proof-of-concept project has begun to verify that the compounds have the photoluminescence and electrochemical properties required for the manufacture of tunable organic LEDs (OLEDs) that can emit in the blue portion of the visible spectrum, thus applying lower voltages and achieving greater efficiency and longer life.

Posted in: Electronics & Computers, Manufacturing & Prototyping, Materials, Energy Efficiency, Energy, Lighting, OLEDs, News

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Researchers Measure Stress in 3D-Printed Metal Parts

Lawrence Livermore National Laboratory researchers have developed an efficient method to measure residual stress in metal parts produced by powder-bed fusion additive manufacturing (AM).The 3D-printing process produces metal parts layer by layer using a high-energy laser beam to fuse metal powder particles. When each layer is complete, the build platform moves downward by the thickness of one layer, and a new powder layer is spread on the previous layer.While the method produces quality parts and components, residual stress is a major problem during the fabrication process. Large temperature changes near the last melt spot, and the repetition of this process, result in localized expansion and contraction.An LLNL research team, led by engineer Amanda Wu, has developed an accurate residual stress measurement method that combines traditional stress-relieving methods (destructive analysis) with modern technology: digital image correlation (DIC). The process provides fast and accurate measurements of surface-level residual stresses in AM parts.The team used DIC to produce a set of quantified residual stress data for AM, exploring laser parameters. DIC is a cost-effective, image analysis method in which a dual camera setup is used to photograph an AM part once before it’s removed from the build plate for analysis and once after. The part is imaged, removed, and then re-imaged to measure the external residual stress.SourceAlso: Learn about Design and Analysis of Metal-to-Composite Nozzle Extension Joints.

Posted in: Cameras, Imaging, Photonics, Lasers & Laser Systems, Manufacturing & Prototyping, Rapid Prototyping & Tooling, Materials, Metals, Test & Measurement, Measuring Instruments, News

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Microbot Muscles Self-Assemble and Flex

In a step toward robots smaller than a grain of sand, University of Michigan researchers have shown how chains of self-assembling particles could serve as electrically activated muscles in the tiny machines."We are inspired by ideas of microscopic robots," said Michael Solomon, a professor of chemical engineering. "They could work together and go places that have never been possible before."Solomon and his group demonstrated that some gold plating and an alternating electric field can help oblong particles form chains that extend by roughly 36 percent when the electric field is on.The team started with particles similar to those found in paint, with diameters of about a hundredth the width of a strand of hair. They stretched these particles into football shapes and coated one side of each football with gold. The gilded halves attracted one another in slightly salty water—ideally about half the salt concentration in the sports drink Powerade. The more salt in the water, the stronger the attraction.Left to their own devices, the particles formed short chains of overlapping pairs, averaging around 50 or 60 particles to a chain. When exposed to an alternating electric field, the chains seemed to add new particles indefinitely. But the real excitement was in the way that the chains stretched."We want them to work like little muscles," said Sharon Glotzer, the Stuart W. Churchill Professor of Chemical Engineering. "You could imagine many of these fibers lining up with the field and producing locomotion by expanding and contracting."SourceAlso: Learn about Microelectronic Repair Techniques for Wafer-Level Integration.

Posted in: Electronics & Computers, Materials, Machinery & Automation, Robotics, News

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Light Bending Material Facilitates Search for New Particles

Particle physicists have a hard time identifying all the elementary particles created in their particle accelerators. But now researchers at Chalmers University of Technology have designed a material that makes it much easier to distinguish the particles.

Posted in: Photonics, Optics, Materials, Solar Power, Energy, News

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Solar Material Converts 90 Percent of Captured Light into Heat

A multidisciplinary engineering team at the University of California, San Diego developed a new nanoparticle-based material for concentrating solar power plants designed to absorb and convert to heat more than 90 percent of the sunlight it captures. The new material can also withstand temperatures greater than 700 degrees Celsius and survive many years outdoors in spite of exposure to air and humidity. “We wanted to create a material that absorbs sunlight that doesn’t let any of it escape. We want the black hole of sunlight,” said Sungho Jin, a professor in the department of Mechanical and Aerospace Engineering at UC San Diego Jacobs School of Engineering. Jin, along with professor Zhaowei Liu of the department of Electrical and Computer Engineering, and Mechanical Engineering professor Renkun Chen, developed the Silicon boride-coated nanoshell material. The novel material features a “multiscale” surface created by using particles of many sizes ranging from 10 nanometers to 10 micrometers. The multiscale structures can trap and absorb light which contributes to the material’s high efficiency when operated at higher temperatures.SourceAlso: Read more Materials tech briefs.

Posted in: Materials, Solar Power, Energy Efficiency, Energy, Nanotechnology, News

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New Computer Codes Enable Design of Greener, Leaner Aircraft

A computer model that accurately predicts how composite materials behave when damaged will make it easier to design lighter, more fuel-efficient aircraft. Innovative computer codes form the basis of a computer model that shows in unprecedented detail how an aircraft's composite wing, for instance, would behave if it suffered small-scale damage, such as a bird strike. Any tiny cracks that spread through the composite material can be predicted using this model. 

Posted in: Electronics & Computers, Green Design & Manufacturing, Greenhouse Gases, Materials, Composites, Software, Aerospace, Aviation, News

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Researchers Develop Thinnest Electric Generator

Researchers from Columbia Engineering and the Georgia Institute of Technology made the first experimental observation of piezoelectricity and the piezotronic effect in an atomically thin material, molybdenum disulfide (MoS2), resulting in a unique electric generator and mechanosensation devices that are optically transparent, extremely light, and very bendable and stretchable.“This material—just a single layer of atoms—could be made as a wearable device, perhaps integrated into clothing, to convert energy from your body movement to electricity and power wearable sensors or medical devices, or perhaps supply enough energy to charge your cell phone in your pocket,” says James Hone, professor of mechanical engineering at Columbia and co-leader of the research.Hone’s team placed thin flakes of MoS2 on flexible plastic substrates and determined how their crystal lattices were oriented using optical techniques. They then patterned metal electrodes onto the flakes. In research done at Georgia Tech, a group led by Zhong Lin Wang, Regents’ Professor in Georgia Tech’s School of Materials Science and Engineering, installed measurement electrodes on the samples provided by Hone’s group, then measured current flows as the samples were mechanically deformed. They monitored the conversion of mechanical to electrical energy, and observed voltage and current outputs.Ultimately, Zhong Lin Wang notes, the research could lead to complete atomic-thick nanosystems that are self-powered by harvesting mechanical energy from the environment. This study also reveals the piezotronic effect in two-dimensional materials for the first time, which greatly expands the application of layered materials for human-machine interfacing, robotics, MEMS, and active flexible electronics.Source Also: Learn more about a Piezoelectric Energy Harvesting Transducer System.

Posted in: Electronics & Computers, Electronic Components, Electronics, Power Management, Materials, Metals, Sensors, Semiconductors & ICs, News

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