Microscopic particles that bind under low temperatures will melt as temperatures rise to moderate levels, but re-connect under hotter conditions, a team of New York Univ. scientists has found. Their discovery points to new ways to create "smart materials," cutting-edge materials that adapt to their environment by taking new forms, and to sharpen the detail of 3-D printing.
Personal electronics such as cell phones and laptops could get a boost from some of the lightest materials in the world. Lawrence Livermore National Laboratory researchers have turned to graphene aerogel for enhanced electrical energy storage that eventually could be used to smooth out power fluctuations in the energy grid.
Graphene’s exotic properties can be tailored by cutting large sheets down to ribbons of specific lengths and edge configurations. But this “top-down” fabrication approach is not yet practical, because current lithographic techniques always produce defects. Now, scientists from the U.S. and Japan have discovered a new “bottom-up” self-assembly method for producing defect-free graphene nanoribbons with periodic zigzag-edge regions.
Researchers in Japan have developed a new yet simple technique called "diffusion driven layer-by-layer assembly" to construct graphene into porous 3-D structures for applications in devices such as batteries and supercapacitors. The new method borrowed a principle from polymer chemistry, known as interfacial complexation, to allow graphene oxide to form a stable composite layer with an oppositely charged polymer.
Researchers at Japan’s National Institute of Advanced Industrial Science and Technology have synthesized an atomic chain in which two elements, cesium and iodine, are aligned alternately inside a carbon nanotube. Analyzed using electron microscopy and spectroscopy, the invention could shed light on the adsorption mechanisms of radioactive elements.
Univ. of Texas at Arlington engineering professors have received an Air Force grant to examine the material surface at the micro- and nano-scale level that will provide clues for predicting fatigue in aircraft parts. The new approach will rely on a scanning whitelight interferometric surface profiler integrated with a compact mechanical tester and an electron backscatter diffraction module to deliver in-situ 3-D surface profiling.
The phase-out of traditional incandescent bulbs in the U.S. and elsewhere, as well as a growing interest in energy efficiency, has given LED lighting a sales boost. That trend could be short-lived as key materials known as rare earth elements become more expensive. Scientists at Rutgers Univ., however, have now designed new materials for making household LED bulbs without using these ingredients.
Scientists report that they have made the first experimental observation of piezoelectricity and the piezotronic effect in an atomically thin material, molybdenum disulfide. This finding has resulted in a unique electric generator and could point the way to mechanosensation devices that are optically transparent, extremely light, and very bendable and stretchable.
Iron catalysts remove oxygen inexpensively, but are susceptible to rust or oxidation in biofuel production. Precious metals that resist corrosion are even less efficient at removing oxygen. But adding just a touch of palladium to the iron produces a catalyst that quickly removes oxygen atoms, easily releases the desired products, and doesn't rust, according to scientists at Pacific Northwest National Laboratory and Washington State Univ.
Using 3-D printing and novel semiconductors, researchers at Oak Ridge National Laboratory have created a power inverter that could make electric vehicles lighter, more powerful and more efficient. At the core of this development is wide bandgap material made of silicon carbide with qualities superior to standard semiconductor materials.
Officials at a Chicago-based startup, Sagamore-Adams Laboratories LLC, say innovations discovered in Purdue University's School of Nuclear Engineering are being commercialized to address challenges in improving radiation detection and making sealants and adhesives safer. They have developed technology that could lead to radiation sensors that cost less and provide better information than traditional sensors.
Swedish and Chinese researchers have recently shown how a unique nano-alloy composed of palladium nano-islands embedded in tungsten nanoparticles creates a new type of catalysts for highly efficient oxygen reduction, the most important reaction in hydrogen fuel cells. Their results are published in the scientific journal Nature Communications.
When trying to design a mechanical system to last as long as possible, scientists and engineers have to find ways of overcoming friction. While researchers have found many materials that help to reduce friction, conventional lubricants often have chemical limitations. A recent analysis at Argonne National Laboratory has identified the properties of a newer, wear-resistant substance that works in a broader range of environments.
Researchers at Oak Ridge National Laboratory have obtained the first direct observations of atomic diffusion inside a bulk material. The research, which could be used to give unprecedented insight into the lifespan and properties of new materials, is published in Physical Review Letters.
Developing the cloak of invisibility would be wonderful, but sometimes simply making an object appear to be something else will do the trick, according to Penn State Univ. engineers. To do this, they employ what they call "illusion coatings," which are made of a thin flexible substrate with copper patterns designed to create the desired result. The metamaterial coatings can function normally while appearing as something else.
A surprising phenomenon has been found in metal nanoparticles: They appear, from the outside, to be liquid droplets, wobbling and readily changing shape, while their interiors retain a perfectly stable crystal configuration. The research team behind the finding says the work could have important implications for the design of components in nanotechnology, such as metal contacts for molecular electronic circuits.
Using a common laboratory filter paper decorated with gold nanoparticles, researchers at Washington Univ. in St. Louis have created a unique platform, known as “plasmonic paper,” for detecting and characterizing even trace amounts of chemicals and biologically important molecules, including explosives, chemical warfare agents, environmental pollutants and disease markers.
When a sturdy material becomes soft and spongy, one usually suspects damage. But this is not always the case, especially in biological cells. By looking at microscopic biopolymer networks, researchers in Germany revealed that such materials soften by undergoing a transition from an entangled spaghetti of filaments to aligned layers of bow-shaped filaments that slide past each other. This finding may explain how other filaments flow.
A long-sought goal of creating particles that can emit a colorful fluorescent glow in a biological environment, and that could be precisely manipulated into position within living cells, has been achieved by a team of researchers at Massachusetts Institute of Technology and several other institutions. The new technology could make it possible to track the position of the nanoparticles as they move within the body or inside a cell.
Researchers have developed a new method for harvesting the energy carried by particles known as “dark” spin-triplet excitons with close to 100% efficiency, clearing the way for hybrid solar cells which could far surpass current efficiency limits. To date, this type of energy transfer had only been shown for “bright” spin-singlet excitons.
A new crystallographic technique, called fast time-resolved crystallography, developed in the U.K. is set to transform scientists’ ability to observe how molecules work. Although this method, also known as Laue crystallography, has previously been possible, it has required advanced instrumentation that is only available at three sites worldwide. Only a handful of proteins have been studied using the traditional technique.
Anyone who has blown a bubble and seen how quickly it pops has first-hand experience on the major challenge in creating stable foams. At its most basic level, foam is a bunch of bubbles squished together. Liquid foams, a state of matter that arises from tiny gas bubbles dispersed in a liquid, are familiar in everyday life, from beer to bathwater. They also are important in commercial products and processes.
It’s a well-known phenomenon in electronics: Shining light on a semiconductor, such as the silicon used in computer chips and solar cells, will make it more conductive. But now researchers have discovered that in a special semiconductor, light can have the opposite effect, making the material less conductive instead. This new mechanism of photoconduction could lead to next-generation excitonic devices.
Axons are the shafts of neurons, on the tips of which connections are made with other neurons or cells. In a new study in Texas, researchers were able to use microfluidic stimulations to change the path of an axon at an angle of up to 90 degrees. The publication adds insight to the long accepted idea that chemical cues are primarily responsible for axonal pathfinding during human development and nervous system regeneration.
Conventional silicon solar cells could have an inexpensive competitor in the near future. Researchers in Europe have examined the working principle of a cell where an organic-inorganic perovskite compound acts as a light absorber. The scientists observed that charge carriers accumulate in a layer in these photovoltaic elements. If this jam can be dissolved, the already considerable efficiency of these solar cells could be further improved.