Archive for superconductivity
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Topological insulators (TIs) are an exciting new type of material that on their surface carry electric current, but within their bulk, act as insulators. Since the discovery of TIs about a decade ago, their unique characteristics (which point to potential applications in quantum computing) have been explored theoretically, and in the last five years, experimentally. But where in theory, the bulk of TIs carry no current, in the laboratory, impurities and disorder in real materials mean that the bulk is, in fact, conductive. This has proven an obstacle to experimentation with TIs: findings from prior experiments designed to test the surface conductivity of TIs unavoidably included contributions from the surplus of electrons in the bulk. Now an interdisciplinary research team at the University of Illinois at Urbana-Champaign, in collaboration with researchers at Brookhaven National Laboratory’s Condensed Matter Physics and Materials Science Department, has measured superconductive surface states in TIs where the bulk charge carriers were successfully depleted. To deplete the electrons in the bulk, the team used three strategies: the TI material was doped with antimony, then it was doped at the surface with a chemical with strong electron affinity, and finally an electrostatic gate was used to apply voltage that lowered the energy of the entire system.
The University of Dayton Research Institute will benefit from the first round of applied research and development project awards the National Additive Manufacturing Innovation Institute announced in a few weeks ago. Rapid Prototype + Manufacturing LLC of Avon Lake, Ohio, was awarded $1 million for “Maturation of Fused Deposition Modeling Component Manufacturing,” and will contract with UD’s Research Institute for $575,000 for technology support and education. Other partners in the program, designed to resolve issues that have inhibited the transition to manufacturing of Fused Deposition Modeling, a popular thermoplastic-based additive process, include Stratasys of Eden Prairie, Minn., as well as aerospace companies Boeing, GE Aviation, Lockheed Martin and Northrop Grumman. “This program allows us to pool resources and leverage highly developed composites industry design practices to mature FDM manufacturing for aerospace and defense applications,” says Brian Rice, head of the Research Institute’s Multi-Scale Composites and Polymers Division. “UDRI’s role will be to analyze material properties and define how to design and certify parts manufactured for aerospace applications.” In July 2012, UDRI received $3 million from the Ohio Third Frontier to work with Stratasys, RP+M and additional partners to develop aircraft-engine components through additive manufacturing —also known as 3D printing—for several aerospace manufacturers.
Eliminating the defects at the interface separating two crystals, or grains, has been shown by nanotechnology experts to be a powerful strategy for making materials stronger, more easily molded, and less electrically resistant-or a host of other qualities sought by designers and manufacturers. Since 2004, when a seminal paper came out in Science, materials scientists have been excited about one special of arrangement of atoms in metals and other materials called a “coherent twin boundary” or CTB. Based on theory and experiment, these coherent twin boundaries are often described as “perfect,” appearing like a perfectly flat, one-atom-thick plane in computer models and electron microscope images. But new research now shows that coherent twin boundaries are not so perfect after all. A team of scientists at the University of Vermont’s College of Engineering and Mathematical Sciences and the Lawrence Livermore National Laboratory and elsewhere report that coherent twin boundaries found in copper “are inherently defective.” With a high-resolution electron microscope, using a more powerful technique than has ever been used to examine these boundaries, they found tiny kink-like steps and curvatures in what had previously been observed as perfect. Even more surprising, these kinks and other defects appear to be the cause of the coherent twin boundary’s strength and other desirable qualities. “Everything we have learned on these materials in the past 10 years will have to be revisited with this new information,” says UVM engineer Frederic Sansoz.
The DOE’s Fuel Cell Technologies Office has issued a request for information seeking feedback from interested stakeholders regarding the use of rotating disk electrode (RDE) experiments and best practices for experimental conditions for characterization of the activity and durability of proton exchange membrane fuel cell oxygen reduction reaction (ORR) electrocatalysts. A review of recent literature shows that the determination of the ORR activity has numerous intricacies that have not been systemically cataloged, resulting in values for the activity of Pt/C that vary significantly. Next steps will be to establish standard procedures and measurement parameters for the RDE technique so that novel catalysts can be benchmarked for ORR activity versus an accepted Pt/C baseline for polymer electrolyte fuel cell applications. DOE is specifically interested in information on best practices/protocols to enable consistency in procedures and less variability in results from different laboratories.
In a process comparable to squeezing an elephant through a pinhole, researchers at Missouri University of Science and Technology have designed a way to engineer atoms capable of funneling light through ultra-small channels. Their research is the latest in a series of recent findings related to how light and matter interact at the atomic scale, and it is the first to demonstrate that the material—a specially designed “meta-atom” of gold and silicon oxide—can transmit light through a wide bandwidth and at a speed approaching infinity. The meta-atoms’ broadband capability could lead to advances in optical devices, which currently rely on a single frequency to transmit light, the researchers say. ”These meta-atoms can be integrated as building blocks for unconventional optical components with exotic electromagnetic properties over a wide frequency range,” write Jie Gao and Xiaodong Yang, assistant professors of mechanical engineering at Missouri S&T, and Lei Sun, a visiting scholar at the university. The researchers created mathematical models of the meta-atom, a material 100 nanometers wide and 25 nanometers tall that combined gold and silicon oxide in stairstep fashion. In their simulations, the researchers stacked 10 of the meta-atoms, then shot light through them at various frequencies. They found that when light encountered the material in a range between 540 terahertz and 590 terahertz, it “stretched” into a nearly straight line and achieved an “effective permittivity” known as epsilon-near-zero. Effective permittivity refers to the ratio of light’s speed through air to its speed as it passes through a material. As light passes through the engineered meta-atoms described by Gao and Yang, however, its effective permittivity reaches a near-zero ratio. In other words, through the medium of these specially designed materials, light actually travels faster than the speed of light. It travels “infinitely fast” through this medium, Yang says.
Acting Secretary of Energy Daniel Poneman announced that DOE is awarding 88 grants to small businesses in 28 states to develop clean energy technologies with a strong potential for commercialization and job creation. These awards, totaling over $16 million in investments, will help small businesses with promising ideas that could improve manufacturing processes, boost the efficiency of buildings, reduce reliance on foreign oil, and generate electricity from renewable sources. Companies competing for these grants were encouraged to propose outside-the-box innovations to meet ambitious cost and performance targets. The small businesses receiving the awards are located in 28 states: Alabama, Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Illinois, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Pennsylvania, Tennessee, Texas, Utah, Virginia, and Washington. Companies competing for these grants were encouraged to propose outside-the-box innovations to meet ambitious cost and performance targets. The selections are for Phase I and Fast Track (combined Phase I and II) work. That means that the new projects will go toward exploring the feasibility of innovative concepts that could be developed into prototype technologies. Seventy-nine awards will go to SBIR projects, and another nine will go to STTR projects.
The Strategic Materials Advisory Council has cautioned the Department of Defense to avoid the risky mitigation strategy of stockpiling strategic and critical materials from China. The DOD recently completed its biannual “Strategic and Critical Materials 2013 Report on Stockpile Requirements,” which recommended stockpiling $120.43 million of heavy rare earth elements—materials produced only in China. ”The root cause of these material shortages is our ongoing dependence on Chinese suppliers,” says Council Executive Director Jeff Green. “While it is encouraging that DoD acknowledges these risks, we urge DOD to move from theoretical studies to the only appropriate and permanent solution: the creation and nurturing of a US-based rare earth supply chain.” The rare earth stockpile recommendation represents over one-third of a $319.74 million stockpiling plan to mitigate a $1.2 billion shortfall of 23 strategic and critical materials. This encouraging recommendation contrasts dramatically with previous DOD assessments that asserted domestic sources could meet all military requirements by 2013, except for yttrium, and that substitution would be a viable approach to risk mitigation for heavy rare earths.
A new chemotherapy drug in the form of nanoparticles is less toxic to young women’s fertility but extra tough on cancer, say researchers. “Our overall goal is to create smart drugs that kill the cancer but don’t cause sterility in young women,” says Teresa Woodruff, a co-principal investigator of the study and chief of fertility preservation at Northwestern University. The chemotherapy drug, arsenic trioxide, is packed into a very tiny Trojan horse called a nanobin. The nanobin consists of nano-size crystalline arsenic particles densely packed and encapsulated in a fat bubble. The fat bubble, a liposome, disguises the deadly cargo-half a million drug molecules. The fat bubble is the perfect size to stealthily slip through holes in the leaky blood vessels that rapidly grow to feed tumors. The local environment of the tumor is often slightly acid and it’s this acid that causes the nanobin to release its drug cargo and deliver a highly effective dose of arsenic where it is needed. The scientists show this approach to packaging and delivering the active drug has the desired effect on the tumor cells but prevents damage to ovarian tissue, follicles, or eggs. Arsenic trioxide was approved a few years ago for treating some types of blood cancers such as leukemia in humans, but the researchers think the arsenic trioxide nanobins can be used against breast cancer and other solid tumors.
At the Hannover trade fair, Fraunhofer researchers are now presenting a new manufacturing process with which these thermoelectric generators can be cost-effectively produced in the form of large-area flexible components from non-toxic synthetic materials. The scientists‘ vision is described by Aljoscha Roch of the Fraunhofer Institute for Material and Beam Technology IWS in Dresden: “Thermoelectric generators (TEG) currently have an efficiency of around eight percent. That sounds very small. But if we succeed in producing TEG cost-effectively, on a large scale and from flexible materials we can install them extensively on the insides of the concave cooling tower wall. In this way, through the enormous amount of energy produced in the huge plants—around 1500 liters of water evaporate per minute—we could generate large quantities of electricity.” The scientists have succeeded in producing TEGs by means of a printing process. The miniaturized generators can not only be produced cost-effectively, on large surfaces and in a flexibly manageable manner, but an additional major advantage is that the materials used are environmentally-friendly. “TEG are today largely produced by hand from toxic components which contain lead for example. We are now using modern 3D printing technology and harmless polymers (plastics) that are electrically conductive,” explains Roch. The IWS researchers are demonstrating the printed TEG for the first time in a cooling tower model at the Hannover trade fair.
Researchers have developed a “hyperbolic metamaterial waveguide” that halts and ultimately absorbs each frequency of light, at slightly different places in a vertical direction, to catch a “rainbow” of wavelengths. The technology is essentially an advanced microchip made of ultrathin films of metal and semiconductors and/or insulators. ”Right now, researchers are developing compact light absorbers based on optically thick semiconductors or carbon nanotubes. However, it is still challenging to realize the perfect absorber in ultrathin films with tunable absorption band,” says Qiaoqiang Gan, an assistant professor of electrical engineering at University at Buffalo. Gan previously helped pioneer a way to slow light without cryogenic gases. He and other researchers at Lehigh University made nanoscale-sized grooves in metallic surfaces at different depths, a process that altered the optical properties of the metal. While the grooves worked, they had limitations. For example, the energy of the incident light cannot be transferred onto the metal surface efficiently, which hampered its use for practical applications. As reported in the journal Scientific Reports, the waveguide solves that problem because it is a large area of patterned film that can collect the incident light efficiently. Researchers say the technology could lead to advancements in an array of fields, such as preventing crosstalk in electronics or energy-harvesting devices.
The High-Pressure Collaborative Access Team (HPCAT), a group linked to the Advanced Photon Source (APS) facility at the Argonne National Lab, held a workshop Oct. 10-12, 2012, to review the successes of HPCAT over the past 10 years, as well as opportunities for addressing key grand challenges in future of extreme conditions science. During the past decade, HPCAT has taken advantage of the nation’s most brilliant high-energy synchrotron source and developed a multitude of integrated synchrotron radiation techniques optimized for high-pressure research. These X-ray probes, integrated with hydrostatic or uniaxial compression, static or dynamic loading, resistive or laser heating, and cryogenic cooling, have enabled users’ investigations of structural, vibrational, electronic, and magnetic properties at high pressure and high/low temperature that were not possible a decade ago. The workshop consisted of over 120 people from the US and abroad. Emerging from the workshop and its discussions is a clear signal of the outstanding opportunities for the future of extreme conditions science at the APS in the years to come. The report is approximately 120 pages (pdf)
New experiments set the record of the superconducting transition temperatures for a new family of iron-based selenide superconductors. These materials were recently found to superconduct below 30 K, but their transition temperatures decline until approaching absolute zero temperature with the application of pressure. Now Carnegie scientists Xiao-Jia Chen, Lin Wang, and Ho-Kwang Mao, in collaboration with scientists from from the National Institute of Standards and Technology, the Chinese Academy of Science, and Zhejiang University, have uncovered reemerging superconductivity above 48 K in iron selenides upon further compression. The disappearance of superconductivity in the low-pressure cycle and the re-emergence of superconductivity with higher transition temperatures in the high-pressure cycle reflect detailed structural variances within the basic unit cell itself. The two superconducting domes were likely the result of different charge carriers. Finding the reentrance of superconductivity at 48 K in the new iron family of superconductors points to the possibility of achieving similar higher transition temperatures at ambient pressure through some structural modifications
New research carried out at MIT and elsewhere has demonstrated for the first time that when inserted into a pool of liquid, nanowires - wires that are only hundreds of nanometers across - naturally draw the liquid upward in a thin film that coats the surface of the wire. The finding could have applications in microfluidic devices, biomedical research and inkjet printers. Although this upward pull is always present with wires at this tiny scale, the effect can be further enhanced in various ways: Adding an electric voltage on the wire increases the force, as does a slight change in the profile of the wire so that it tapers toward one end. The researchers used nanowires made of different materials—silicon, zinc oxide and tin oxide, as well as two-dimensional graphene—to demonstrate that this process applies to many different materials. The results are published in the journal Nature Nanotechnology by a team of researchers led by Ju Li, an MIT professor of nuclear science and engineering and materials science and engineering, along with researchers at Sandia National Laboratories in New Mexico, the University of Pennsylvania, the University of Pittsburgh, and Zhejiang University in China. Several brief videos of the nanowires in action have been posted on YouTube by Li’s research group.
Even graphene, the Superman of materials, has its kryptonite: Defects in polycrystalline graphene will sap its strength. The unexpected weakness is in the form of a seven-atom ring that inevitably occurs at the junctions of grain boundaries in graphene, where the regular array of hexagonal units is interrupted, report researchers. At these points, under tension, polycrystalline graphene has about half the strength of pristine samples of the material. New research shows defects in polycrystalline forms of graphene will sap its strength. The new calculations could be important to materials scientists using graphene in applications where its intrinsic strength is a key feature, like composite materials and stretchable or flexible electronics. The team calculated that the particular seven-atom rings found at junctions of three islands are the weakest points, where cracks are most likely to form. These are the end points of grain boundaries between the islands and are ongoing trouble spots.
Here’s what we are reading about:
A multi-university team of researchers has artificially engineered a unique multilayer material that could lead to breakthroughs in both superconductivity research and in real-world applications. The researchers can tailor the material, which seamlessly alternates between metal and oxide layers, to achieve extraordinary superconducting properties - in particular, the ability to transport much more electrical current than non-engineered materials. The team includes experts from the Univ. of Wisconsin-Madison, Florida State Univ. and the Univ. of Michigan. The group described its breakthrough March 3, 2013, in the advance online edition of the journal Nature Materials. The researchers’ new material is composed of 24 layers that alternate between the pnictide superconductor and a layer of the oxide strontium titanate. The researchers maintained an atomically sharp interface. The new material also has improved current-carrying capabilities. As they grew the superlattice, the researchers also added a tiny bit of oxygen to intentionally insert defects every few nanometers in the material. These defects act as pinning centers to immobilize tiny magnetic vortices that, as they grow in strength in large magnetic fields, can limit current flow through the superconductor.
(Ars Technica) A group of researchers in Germany who have a history of working with lithium-air batteries have turned their attention to sodium-air. The reason for the change is that lithium-air has some unfortunate chemistry that has proven difficult to overcome. The researchers wanted a simpler system that might not have as many technical hurdles. It turns out that sodium-air provides this system. The battery they constructed is very simple. There’s a solid sodium electrode at one end. On top of that an electrolyte is placed, then an air-permeable carbon electrode. The metal atoms release an electron that travels through a circuit to do work while the ionic form of the metal dissolves into the electrolyte and travels to the carbon electrode. At that electrode it combines with oxygen and an electron to form sodium oxide. It’s important to remember that this is very much exploratory, so the news is quite mixed. It certainly can’t compare with a commercial lithium-ion battery, but it compares very well with lithium-air. The researchers found that it was easier to charge, held more charge, and had better discharge characteristics. In other words, even though lithium-air has a higher theoretical energy density, sodium-air has a higher practical energy density. Further, that energy is stored in the battery more efficiently and can be extracted more efficiently.
The adsorption of ions in microporous materials governs the operation of technologies as diverse as water desalination, energy storage, sensing, and mechanical actuation. Until now, however, researchers attempting to improve the performance of these technologies haven’t been able to directly and unambiguously identify how factors such as pore size, pore surface chemistry and electrolyte properties affect the concentration of ions in these materials as a function of the applied potential. To provide the needed information, researchers at the Georgia Institute of Technology and the Oak Ridge National Laboratory have demonstrated that a technique known as small angle neutron scattering (SANS) can be used to study the effects of ions moving into nanoscale pores. Believed to be the first application of the SANS technique for studying ion surface adsorption in-situ, details of the research were reported recently in Angewandte Chemie International Edition. Using conductive nanoporous carbon, the researchers conducted proof-of-concept experiments to measure changes in the adsorption of hydrogen ions in pores of different sizes within the same material due to variations in solvent properties and applied electrical potential. Systematic studies performed with such a technique could ultimately help identify the optimal pore size, surface chemistry and electrolyte solvent properties necessary for either maximizing or minimizing the adsorption of ions under varying conditions
When a crystal is hit by an intense ultrashort light pulse, its atomic structure is set in motion. A team of scientists from the Max Planck Institute of Quantum Optics, the Technischen Universität München, the Fritz-Haber Institute in Berlin, and the Universität Kassel can now observe how the configuration of electrons and atoms in titanium dioxide, a semiconductor, changes under the impact of an ultraviolet laser pulse, confirming that even subtle changes in the electron distribution caused by the excitation can have a considerable impact on the whole crystal structure. The physicists illuminated a titanium dioxide crystal with an intense ultraviolet laser pulse of less than five femtoseconds duration. The laser pulse excites the valence electrons in the crystal and generates a small number of hot electrons with a temperature of several thousand Kelvin. Following the first, intense laser pulse, the changes in the reflectivity of the crystal on the femtosecond timescale were observed by a second, weak light pulse. This measurement provides the scientists with information on the changes in the crystal induced by the first laser pulse: the intense ultraviolet laser pulse did not only heat up the valence electrons but also changed the electron distribution within the lattice.
A white Hyundai ix35 Fuel Cell (PEM-type) vehicle rolled off the assembly line at the company’s Ulsan manufacturing facility today, as Hyundai became the world’s first automaker to begin assembly-line production of zero-emissions, hydrogen-powered vehicles for fleet use. The ix35 Fuel Cell vehicle, based on Hyundai’s popular ix35, C-segment SUV, exited the assembly line at Hyundai Motor Company’s Plant No. 5 during a launch event attended by Hyundai top management and VIPs. The ix35 Fuel Cell unveiled at the ceremony will be one of 17 destined for fleet customers in the City of Copenhagen, Denmark, and Skåne, Sweden. Copenhagen, as part of its initiative to be carbon-free by 2025, will be supplied with 15 ix35 vehicles for fleet use, according to an agreement that was announced in September 2012. Two also will be supplied to Skåne, Sweden. “Assembly-line production of fuel cell vehicles marks a crucial milestone in the history of the automobile industry not just in Korea, but throughout the world,” says Mang Woo Park, mayor of Ulsan city. Hyundai plans to build 1,000 ix35 vehicles by 2015 for lease to public and private fleets, primarily in Europe, where the European Union has established a hydrogen road map and initiated construction of hydrogen fueling stations.
With imported petroleum dropping from 60 percent of total consumption to less than 40 percent in the past six years, in part due to the explosion of onshore oil exploration and development, the US has made progress toward its goal of reducing dependence on foreign oil. On March 5, energy leaders will come together with faculty of the University of Oklahoma Price College of Business Energy Institute for a national energy symposium with the objective of developing a long-term energy strategy for the country. Some of the nation’s leading energy executives, economists and national security leaders will share their diverse perspectives to identify priorities and challenges in shaping a cohesive energy strategy and enabling policy. The long-term energy strategy symposium organizers expect to develop will be designed to address the realities of energy resource options, take into account global resources, competition and US options, and provide a balanced view of resource reliability, economics and environmental impact. Panelists also will address the role of government in energy policy that they believe would enable successful implementation for a cohesive, long-term energy strategy. The keynote speaker is Adam Sieminski, administrator, US Energy Information Administration.
(Nature) Glass transition, in which viscosity of liquids increases dramatically upon decrease of temperature without any major change in structural properties, remains one of the most challenging problems in condensed matter physics despite tremendous research efforts in past decades… [T]he characterization of the similarity between spin and the structural glass transition remains an elusive subject. In this study, we introduced a model structural glass with built-in quenched disorder that alleviates this main difference between the spin and molecular glasses, thereby helping us compare these two systems: the possibility of producing a good thermalization at rather low temperatures is one of the advantages of this model.
Lots of interesting things going on around the US and the world:
A new type of nanoscale engine has been proposed that would use quantum dots to generate electricity from waste heat, potentially making microcircuits more efficient. The engines would be microscopic in size, and have no moving parts. Each would only produce a tiny amount of power—a millionth or less of what a light bulb uses. But by combining millions of the engines in a layered structure, researchers at the University of Rochester say a device that was a square inch in area could produce about a watt of power for every one degree difference in temperature. They say the path the electrons have to take across both quantum dots can be adjusted to have an uphill slope. To make it up this (electrical) hill, electrons need energy. They take the energy from the middle of the region, which is kept hot, and use this energy to come out the other side, higher up the hill. This removes heat from where it is being generated and converts it into electrical power with a high efficiency. To do this, the system makes use of a quantum mechanical effect called resonant tunneling, which means the quantum dots act as perfect energy filters. When the system is in the resonant tunneling mode, electrons can only pass through the quantum dots when they have a specific energy that can be adjusted. All other electrons that do not have this energy are blocked.
A team of researchers from Russia, Spain, Belgium, the UK and the DOE’s Argonne National Laboratory announced findings last week that may represent a breakthrough in applications of superconductivity. The team discovered a way to efficiently stabilize tiny magnetic vortices that interfere with superconductivity-a problem that has plagued scientists trying to engineer real-world applications for decades. The discovery could remove one of the most significant roadblocks to advances in superconductor technology. When magnetic fields reach a certain strength, they cause a superconductor to lose its superconductivity. But there is a type of superconductor-known as “Type II”-which is better at surviving in relatively high magnetic fields. In these superconductors, magnetic fields create tiny whirlpools or “vortices.” Superconducting current continues to travel around these vortices to a point, but eventually, as the magnetic field strengthens, the vortices begin to move about and interfere with the material’s superconductivity, introducing resistance. Scientists have spent a lot of time and effort over the past few decades trying to immobilize these vortices, but until now, the results have been mixed. The team, however, discovered a surprise. They began with very thin superconducting wires that could accommodate only one row of vortices. When researchers applied a high magnetic field, the vortices crowded together in long clusters and stopped moving. Increasing the magnetic field restored the material’s superconductivity, instead of destroying it. Next, the team carved superconducting film into an array of holes so that only a few vortices could squeeze between the holes, where they stayed, unable to interfere with current.
A new form of clean coal technology reached an important milestone recently, with the successful operation of a research-scale combustion system at Ohio State University. The technology is now ready for testing at a larger scale. For 203 continuous hours, the Ohio State combustion unit produced heat from coal while capturing 99 percent of the carbon dioxide produced in the reaction. The key to the technology is the use of tiny metal beads to carry oxygen to the fuel to spur the chemical reaction. The fuel is coal that’s been ground into a powder, and mixed with metal beads made of iron oxide composites. The coal and iron oxide are heated to high temperatures, where the materials react with each other. Carbon from the coal binds with the oxygen from the iron oxide and creates carbon dioxide, which rises into a chamber where it is captured. Hot iron and coal ash are left behind. Because the iron beads are so much bigger than the coal ash, they are easily separated out of the ash, and delivered to a chamber where the heat energy would normally be harnessed for electricity. The coal ash is removed from the system. The carbon dioxide is separated and can be recycled or sequestered for storage. The iron beads are exposed to air inside the reactor, so that they become re-oxidized be used again. The beads can be re-used almost indefinitely, or recycled.
Silicon, the material of high-tech devices from computer chips to solar cells, requires a surface coating before use in these applications. The coating “passivates” the material, tying up loose atomic bonds to prevent oxidation that would ruin its electrical properties. But this passivation process consumes a lot of heat and energy, making it costly and limiting the kinds of materials that can be added to the devices. Now a team of MIT researchers has found a way to passivate silicon at room temperature, which could be a significant boon to solar-cell production and other silicon-based technologies. Typically, silicon surfaces are passivated with a coating of silicon nitride, which requires heating a device to 400°C. By contrast, the team’s process team uses organic vapors decomposed over wires heated to 300°C, but the silicon itself never goes above 20°C.
Workers began installing thousands of energy-efficient glass panels at the base of 1 World Trade Center Friday. The panels will adorn the podium wall and are designed to maximize sunlight while keeping the inside cool. LED lights will be housed within the panels, which officials say will give the base a look that is both visually pleasing and environmentally friendly. More than 4,000 glass panels will be used to cover the buildings base.
A new material that generates electricity from body heat could lead to clothing that can keep a mobile phone charged. The material developed by scientists in South Korea is an organic thermoelectric generator (TEG) that produces an electric charge from the temperature difference between the body and the environment and can be formulated as a flexible, cuttable film. The researchers from Yonsei University led by Eunkyoung Kim, synthesised a polymer based on an electrically conductive material known as PEDOT (poly(3,4-ethylenedioxythiophene)), which has been investigated for use protecting the cathodes and anodes in fuel cells from fouling. Kim’s team combined a method to polymerise the material directly from solution with a reduction/oxidation reaction. This produced a material that has a power factor—a measure of how much electricity can be produced related to the temperature difference-of 1270µM/m/K2, four times higher than any previous organic TEG. The material is flexible enough to be incorporated into clothing and the team now hope to use the material to produce a wearable item that can harvest electricity from human body heat.
Background image: Molten glass. Credit: Michael Germann; Dreamstime.com.
Peter and I thought it would be fun to share our five favorite posts from 2012. Finding that choosing only five was nigh impossible, I decided to sort my picks into three categories, which instantly grew my budget to 15 stories!
Advances in science and engineering are subject to forces beyond physics, chemistry, and mathematics, such as politics, culture, history, and more.
USPTO issues flurry of new rules to implement ‘America Invents Act’
Archaic US patent rules were thrown out with adoption of the Leahy-Smith America Invents Act. New rules, though, mean changes in the strategy of innovation.
Data drives engineering of ceramics; workshop asks ‘how well?’
Computational approaches to materials engineering are only as good as the data they consume and digest. A DOD-sponsored workshop evaluated the state-of-affairs for electronic access to ceramic property data and the attendant challenges and opportunities.
Science research drives economic growth, but it’s expensive and slow
What role should governments take in investing in basic research, and how does a nation’s R&D investment impact GDP? There is nothing like an election year—in the US and abroad—to draw attention to what governments should spend money on versus what they do spend money on.
Video: Grand challenges in ceramic science—Preliminary findings from workshop
Researchers go bravely where others cannot or dare not. A group of the nation’s top ceramic science researchers convened to tease out the largest scientific challenges that can be addressed with ceramic materials.
Historic January 1987: YBCO superconductors discovered and Super Bowl XXI
This story about the discovery of high-temperature YBCO superconductors shows that research breakthroughs are often the progeny of systematic, well-executed fundamental research… and serendipity.
I’m an unabashed materials geek, and these were some of my favorite super-sciency stories—with the qualification that I mostly write about science that intrigues me, so this is a lot like choosing a favorite child.
Understanding the ‘between’ spaces: Interfacial phases and solid-state sintering
The formation and stability of interfacial phases in the solid state drives properties, so understanding how interfaces form and the thermodynamics driving them is of paramount importance.
Mullite-like mixed oxides may replace platinum for catalyzing diesel pollution
Manganese-oxide compounds with the mullite crystal structure may one day displace platinum as the catalyst agent in automobile catalytic converters.
High-alumina optical fibers get around Brillouin scattering limitations
Ever wonder how data gets to your smart phone or laptop so fast? A group of glass scientists is working on the next generation on optical fibers that will move more data, faster, and with more accuracy.
High critical current density doped pnictide superconductors
Harnessing the promise of high-temperature superconductivity requires a deep understanding of the physics of magnetism and the influences of composition and microstructure. Plus, what’s not to love about the word “pnictide?”
Heat transfer—two new studies look at effects of interface bonding, surface roughness
The digital age is generating some very sophisticated heat transfer challenges. How exactly does heat egress from a surface, and how can the mechanism be engineered?
Useful metrics for comparing new energy storage technologies
Measuring is an essential experimental activity. However, scientists and engineers must continually ask themselves the question, “Am I measuring something meaningful and useful?”
And this last group of five was just fun to write about.
Don’t wait in line for coffee: How to know where the business opportunity is
A reflection on business, opportunity, finding the way, and waiting in line.
Oldest known pottery dates back 20,000 years and may have changed the course of human history
The earliest ceramic engineers designed pots for cooking and brewing, proof that since time immemorial, engineers bring the life of the party. Literally.
Friday fun video—Gravity-defying Slinky
Adulthood does not mean toys become irrelevant. This video shows that scientists never stop learning the lessons that educational toys can teach.
Technical ceramics and art ceramics—only a brain apart
In the world of ceramics, is there a line between art and science? Yes, sort of—and no, not really. The American Ceramic Society serves the professional needs of engineers, scientists, studio artists, and hobbyists.
A castle vacation, poster session included
An October vacation to Germany included a conference at a Bavarian castle and the opportunity to talk shop with some of the best minds in the world working on biomineralization.
Were you counting? Me neither. Did you have a favorite story or topic that we covered? Let us know!
Best wishes for a Happy New Year!