Modern research has found no simple, inexpensive way to alter a material’s thermal conductivity at room temperature. That lack of control has made it hard to create new classes of devices that use phonons, rather than electrons or photons, to harvest energy or transmit information. Phonons have proved hard to harness.
Traps. Whether you’re squaring off against the Empire or trying to wring electricity out of...
When a metal tube lines an oil well thousands of feet below the surface of the ocean, that metal...
At Penn State, a group led by Melik Demirel, professor of engineering science and mechanics, is designing a biodegradable plastic from structural proteins that could help clean up the world's oceans and solve an interesting set of other problems along the way.
Researchers at the University of Pennsylvania have now shown an important commonality that seems to extend through the range of glassy materials. They have demonstrated that the scaling between a glassy material’s stiffness and strength remains unchanged, implying a constant critical strain that these materials can withstand before catastrophic failure.
Graphene’s great strength appears to be determined by how well it stretches before it breaks, according to Rice Univ. scientists who tested the material’s properties by peppering it with microbullets. The 2-D carbon honeycomb discovered a decade ago is thought to be much stronger than steel. But the scientists didn’t need even a pound of graphene to prove the material is on average 10 times better than steel at dissipating kinetic energy.
A tensile strength is a common materials test. Typical, a sample is subjected to controlled tension until it fails, providing valuable data for fundamental materials development or quality control. The key data acquired include maximum elongation, reduction in cross-section and ultimate tensile strength. Derived from these are a host of properties: Young’s modulus, yield strength, Poisson’s ratio and strain-hardening characteristics.
Making a paper airplane in school used to mean trouble. Today it signals a promising discovery in materials science research that could help next-generation technology get off the ground. Researchers at Drexel Univ. and Dalian Univ. of Technology in China have chemically engineered a new, electrically conductive nanomaterial that is flexible enough to fold, but strong enough to support many times its own weight.
An overwhelming number of chemicals from household and industrial products are in the environment, and hundreds are in our bodies. But for most of them, scientists have yet to determine whether they cause health problems. Now they’ve taken the first step toward doing that by estimating which substances people are exposed to the most.
Researching the safety of nanoparticles is all the rage. Thousands of scientists worldwide are conducting research on the topic, examining the question of whether titanium dioxide nanoparticles or carbon nanotubes can get into the body’s lungs or blood. However, the amount of new knowledge has only increased marginally. How do nanoparticles get into the body? Researchers in Switzerland are attempting to establish standards.
Researchers with CiQUS in Spain have developed a new method to overcome limitations of surface enhanced Raman spectroscopy (SERS), an ultra-sensitive analytical technique able to detect chemicals in very low concentration. The research results show how to cut production costs of substrates and also tackle the lack of reproducibility usually associated to this technique.
Researchers at McGill Univ. have succeeded in simultaneously observing the reorganizations of atomic positions and electron distribution during the transformation of the “smart material” vanadium dioxide from a semiconductor into a metal. The observations are made in a time frame a trillion times faster than the blink of an eye.
Several types of plastic pipes in eco-friendly green buildings in the U.S. have been found to leach chemicals into drinking water that can cause odors and sometimes exist at levels that may exceed health standards. Purdue Univ. engineering professor Andrew Whelton will detail these findings during the 2014 U.S. Green Building Council’s Greenbuild International Conference & Exposition on Oct. 24 in New Orleans.
Research at Oak Ridge National Laboratory has cracked one mystery of glass to shed light on the mechanism that triggers its deformation before shattering. The study improves understanding of glassy deformation and may accelerate broader application of metallic glass, a moldable, wear-resistant, magnetically exploitable material that is thrice as strong as the mightiest steel and ten times as springy.
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.
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 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.
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.
Imagine being able to tune the properties of a solid material just by flashing pulses of light on it. That is one potential payoff of electrons and atoms interacting with ultrashort pulses of light. The technology of ultrafast spectroscopy is a key to understanding this phenomenon and now a new wrinkle to that technology, observations of electron self-energy, has been introduced by Lawrence Berkeley National Laboratory researchers.
You can brush your teeth, and wash yourself and your clothes with a clear conscience. The most common soaps, shampoos and detergents actually pose a minimal risk to the environment. This is the conclusion of a comprehensive survey that covers more than 250 scientific studies over several decades.
Drawn relentlessly by their electrical charges, lithium ions in a battery surge from anode to cathode and back again. Yet, no one really understands what goes on at the atomic scale as lithium ion batteries are used and recharged. Using transmission electron microscopy, researchers are now glimpsing what can happen to anodes as lithium ions work their way into them. The “atomic shuffling” these ions perform leads to rapid anode failure.
A Duke Univ. team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting, an action they say could indirectly damage the aquatic food chain. According to the research, the risk to humans ingesting the particles through drinking water is slight, but aquatic food chains might be harmed by molecules "piggybacking" on the carbon nanoparticles.
In a rare case of having their cake and eating it too, scientists from NIST and other institutions have developed a toolset that allows them to explore the complex interior of tiny, multi-layered batteries they devised. It provides insight into the batteries’ performance without destroying them, which results in both a useful probe for scientists and a potential power source for micromachines.
Researchers from the Univ. of Texas at Dallas have created technology that could be the first step toward wearable computers with self-contained power sources or, more immediately, a smartphone that doesn’t die after a few hours of heavy use. This technology taps into the power of a single electron to control energy consumption inside transistors, which are at the core of most modern electronic systems.
A novel x-ray technique used at the U.S. Department of Energy’s Advanced Photon Source has revealed surprising dynamics in the nanomechanics of operating batteries and suggests a way to mitigate battery failures by minimizing the generation of elastic energy. The method could open a path to wider use of these batteries in conjunction with renewable energy sources.
Scanning electron microscopes can determine chemical compositions with the help of energy dispersive spectrometers. However, lighter elements like carbon emit secondary fluorescence in an energy range insufficiently resolved by these instruments. Physicists have developed a potential solution to this problem by adding reflection zone plate optics to a specialized spectrometer that delivers high resolution from 50 to 1,120 eV.
If it's true that good things come in small packages, then NIST can now make anyone working with nanoparticles very happy. The institute recently issued Reference Material (RM) 8027, the smallest known reference material ever created for validating measurements of man-made, ultrafine particles between 1 and 100 nm in size.
using an aberration-corrected scanning transmission electron microscope, researchers have recently understood how defects in 2-D crystals such as tungsten disulphide can move, or dislocate, to other locations in the material. Understanding how atoms "glide" and "climb" on the surface of 2-D crystals may pave the way for researchers to develop materials with unusual or unique characteristics.
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