Corning announces expansion of clean-air products facilities

Corning Inc. announced that its board of directors has approved a capital expenditure plan of approximately $250 million to increase manufacturing capacity of the company’s diesel emissions control products. The majority of the investment will increase capacity at the Erwin diesel facility near Corning, which manufactures large ceramic substrates and filters for heavy-duty diesel engine, truck, construction, and agricultural equipment manufacturers worldwide. “Important heavy-duty regulations in China and Europe, as well as for non-road vehicles, take effect over the next two years which could double demand for our products by 2017,” says Mark Beck, executive vice president, Corning Environmental Technologies & Life Sciences Business Group. Corning’s diesel plant in Erwin began manufacturing large substrates in 2004 and now also produces particulate filters for heavy-duty applications. The company has already completed two facility expansions to accommodate global market growth. Corning said spending on the $250 million project will occur over a three-year period and will not change the company’s previous capital spending forecasts for 2013 and 2014. The latest project is expected to be operational in 2015 and to create an additional 250 new full-time positions if market demand grows as expected.

Infab Refractories: Excelling in a hot market

Infab Refractories Inc. is a descendant of Eastern Refractories Co, which opened a branch office in Lewiston on Holland Street in the 1940s. The Lewiston satellite was located strategically with a rail siding, for delivery of the refractory firebricks needed to service the boilers of various power plants, paper mills and manufacturing plants. The company was sold to a national contractor in the late ’90s and was soon re-sold, becoming employee owned in 2004. David Collins, the principle owner of Infab Refractories, is the grandson of the first regional manager of Eastern Refractories, Ted Collins. Infab Refractories has expanded its client base through the manufacture of custom-made, removable insulation blankets and various other high-temperature products under the direction of owner Jean (John) Bergeron and former owner Dick Marston at their current location on the corner of Whipple and Summer streets in Lewiston.

Minerals Technologies reports Q1 earnings of $0.53 per share, a 4 percent increase over 2012

Minerals Technologies Inc. (reported net income of $18.8 million, or $0.53 per share for the first quarter 2013, compared with $18.0 million, or $0.51 per share in the first quarter of 2012, a 4-percent increase. “We began 2013 with solid operating performance, which generated a record in profit for both Minerals Technologies and our Specialty Minerals segment,” says Joseph C. Muscari, executive chair. “During the quarter we saw organic growth from new satellites ramping up in Asia, and we also announced three new commercial agreements for our FulFill technology, two in North America and one in South America.” The company’s worldwide sales declined 2 percent to $251.3 million from $257.1 million in the first quarter of 2012. Foreign exchange had an unfavorable impact of 1 percentage point of this decline, and two fewer days in the quarter affected sales by an additional 2 percentage points. Operating income was $27.1 million, a 1-percent increase over the $27.0 million recorded in the prior year’s first quarter.

Fiber cement has cost and durability on its side

(Washington Post) Fiber cement, a century-old material, has become popular in recent decades as a cheaper, more durable alternative to wood siding. It used to be reinforced with asbestos until the 1980s, when that hazardous substance was eliminated from its manufacture. Now the material is typically made with cement, sand, wood fibers and additives. In recent years, designs made from the mixture have expanded from wood-grained boards to paneling resembling brick, stone and stucco, and contemporary furnishings. “We use it on about 90 to 95 percent of our remodeling and addition projects,” says Bill Millholland, executive vice president of Case Design and Remodeling of Bethesda. “I can’t think of much we are doing that is not fiber cement. It looks like real wood siding, but it doesn’t decay, and it’s fire-resistant.” James Hardie Industries is the largest producer of the material in the country, and its HardiePlank siding “has become the Kleenex of fiber cement,” Millholland says.

Tanzania: Cement output to double in two years

(Tanzania Daily News) Tanzania’s total cement production is expected to more than double over the next two years, thanks to the new entrants, which expect to amplify competition. The current four firms that produce Twiga, Simba, Rhino and Tembo brands have a combined installed annual capacity of 3.75 million [metric] tons and output is expected to reach 8.65 million tons per year in 2015. The new producers are Dangote Cement, Lake Cement, and Lee Building Material plus the existing firms’ expansion expected to boost production by 4.9 million tons per annum. Tanzania Securities’ CEO, Moremi Marwa, says the firms are taking advantages of increased cement demand pushed by construction activities that grew at an annual average rate of eight per cent over the past five years. “We expect local demand to grow at over 10 per cent if infrastructure investments are sustained at the current levels and the economic momentum remains as projected,” Marwa says. The demand, currently standing at four million tons, has been growing at a compound annual growth rate of 10 per cent over the past five years to 2012. “We note that Tanzania is currently a net importer of cement, importing about 500,000 tons per annum or 12 per cent of the total consumption,” the CEO says in a cement analysis report. He adds, “We estimate that current sector utilization of the installed capacity is 90 per cent, offering minimal room for upside unless the projected new capacity is added.”

New battery anode with four times the capacity of conventional materials

XG Sciences Inc. announced today that it has launched a new generation of anode materials for lithium-ion batteries with four times the capacity of conventional anodes. The new anode material is produced through proprietary manufacturing processes and uses the company’s xGnP graphene nanoplatelets to stabilize silicon particles in a nano-engineered composite structure. The material displays dramatically improved charge storage capacity with good cycle life and high efficiencies. “We are pleased to announce the immediate availability of this new high-capacity anode product,” says Rob Privette, vice president of energy markets. “Our new silicon-graphene anode material, when used in combination with our existing xGnP graphene products as conductive additives, provides significantly higher energy storage than conventional battery materials. This is great news for applications like smartphones, tablet computers, stationary power and vehicle electrification that use rechargeable lithium-ion batteries. We are working with battery makers to translate this exciting new material into batteries with longer run-time, faster charging and smaller sizes than today’s batteries.” Privette says that the exact performance of the new anode materials will depend on the specific battery formulations used by the cell manufacturer, noting that XGS has demonstrated capacity of 1500 mAh/g with low irreversible capacity loss and stable cycling performance in life tests.

3M LED Advanced Light and 3M Molecular Detection System honored with Edison awards

3M announced that two of its recent technologies have received prestigious honors from the Edison Awards, a program conducted by the non-profit organization Edison Universe, which is dedicated to fostering future innovators. The company’s 3M LED Advanced Light received a Gold Edison Award in the Lighting category while the 3M Molecular Detection System earned a Silver Edison Award within the Diagnostic/Analytic Systems category. Nominees were judged by a panel of more than 3,000 leading business executives including previous winners, academics, and leaders in the fields of product development, design, engineering, science and medicine. The evaluation criteria used for this comprehensive, peer-reviewed process emphasized themes of concept, value, delivery and impact. The 3M LED Advanced Light—the company’s first-ever bulb—couldn’t be more appropriate for an innovation award named after Thomas Edison. The 3M LED Advanced Light provides an option that’s just as bright as a traditional bulb, and with its special Light Guide Technology, it shines in all directions. Developed with 3M multilayer optical film, adhesives and heat management technologies, the stylish bulb provides long-term cost savings but doesn’t compromise on energy efficiency.

Share

“Honeycomb” monolith diesel exhaust filter on left compared to Empa’s ceramic foam substrate filter, right. Credit: Empa.

By this time next year, Europe will be enforcing a tough, new standard on exhaust emissions from trucks and busses. Starting in September 2014, all new passenger and many lighter-weight commercial vehicles in regions covered by the European Commission’s rules will be required to have “Euro 6″-certified engines, and, in response, vehicle manufacturers and various research groups have been accelerating their filtration R&D. Switzerland’s Empa is of the institutions focusing on this issue, and researchers there say they are excited about some unconventional restructuring of the main filter components—typically ceramic substrates—that they say will enable manufacturers to meet pollution goals.

Heretofore, the standard diesel emissions filter is an extruded honeycomb-structure ceramic (e.g., cordierite) substrate that has a light coating of a catalytic material, such as platinum or palladium, which allows it to convert NO_x and CO in the exhaust and capture soot. The honeycomb monolith substrate can withstand the stresses of temperature cycling during normal use and also during “regenerative” cycles when collected particulates (soot) are removed.

The conventional approach to engineering these filters is to allow exhaust gasses to pass through relative easily while providing maximum exposure to the surfaces bearing the catalyst. Turbulence was a thing to be avoided.

However, one research group at Empa, its Internal Combustion Engines Laboratory, says there is a downside to the honeycomb monolith: The flow of the exhaust gasses is distributed unevenly. Most of the exhaust gasses pass through the center section of the filter, creating a high-temperature zone and leaving much of the outer regions of the honeycomb relatively unused. To compensate for the unused regions, Empa says the honeycomb filters have to be relatively long (besides adding general manufacturing costs, the extra length also means the use of extra expensive catalytic material).

This honeycomb catalyst from a racing car was the trigger that gave the Empa researchers the idea of developing the Foamcat. A small area of the monolith has melted, but neighboring areas are almost unused, indicating that the exhaust gas flow is poorly distributed through the device. Credit: Empa.

Empa claims that the impetus for rethinking the filter design was the viewing of a diesel filter whose central section had partially melted (see photo). The researchers’ novel idea, which began to emerge a few years ago, was to embrace the turbulence of the exhaust and put it to use to distribute the gasses more evenly.

But, a rugged ceramic substrate to support the catalyst would still be needed, and the Internal Combustion Engines Lab turned to researchers in Empa’s High-Performance Ceramics Laboratory. Instead of relying on the straight-through openings of a honeycomb, the ceramics group began to tinker with a special catalyst-coated ceramic foam, which they subsequently named Foamcat. The structure of the foam would encourage the turbulence needed to more evenly distribute the exhaust through the filter.

To filter engineers, the Empa approach probably raises several questions, especially in regard to the mechanical strength of a ceramic foam and to the negative effects of the turbulence, i.e., loss of engine performance due to back pressures from the exhaust. In response, a news release from the institute says

[S]cientists succeeded in increasing the mechanical strength of the material many times over. Currently the research team is working to optimize the structure of the ceramic—the foam substrate has a greater air resistance than the monolith that results in a slight comparative increase in fuel consumption. Using sophisticated computer simulation techniques, the Empa team has developed foam structures which reduce the air resistance without affecting the necessary turbulence.

According to Empa, the bottom-line benefit is that the surface area of the Foamcat substrate is much more efficiently used than with a honeycomb monolith. It claims that the efficiency is improved so much that the Foamcat filter can match the performance of a honeycomb filter at half the length and only requires one third of the expensive catalysts.

Whether vehicle manufacturers ultimately embrace the ceramic foam design remains to be seen. The problem of the expense of noble metal catalysts is vexing to manufacturers and other groups have been trying to find substitutes such as acicular mullite.

Nevertheless, Empa says it has been partnering for over a year with catalyst-maker Umicore and diesel engine manufacturer Fiat Powertrain Technologies to do field tests with a Foamcat filters. It also says that Swiss electrical utility IWB has been testing a vehicle fitted with the Foamcat filter for 18 months.

The stakes are high. According to a document (pdf) on the Euro 6 standards prepared by Cummins, all NOx emissions will have to be 75 percent less and particulate matter will have to be 66-95 percent less than current “Euro 5″ limits.

Share

How energy harvesting tech could power wearables and the internet of things

(GigaOm) It’s all very well talking about the evolution of wearable computing and the internet of things, but something has to power these thin and/or tiny devices. For that reason, it’s a good thing that so many ideas are popping up in the field of energy harvesting and storage. Some of these ideas were on display this week at the Printed Electronics Europe 2013 event in Berlin, which took in a variety of sub-events including the Energy Harvesting & Storage Europe show. The concepts ranged from the practical to the experimental, so let’s start with the practical.

S.D. School of Mines: Generating sustainable hydrogen energy goal of splitting water molecules

Finding a way to exponentially double the hydrogen atoms to create a sustainable amount of hydrogen regeneration so that a new form of energy can be harvested is the ultimate goal of researchers at the South Dakota School of Mines & Technology. Rajesh Shende, PhD, and Jan Puszynski, PhD, of the Department of Chemical and Biological Engineering, have been awarded a $299,975 NSF three-year grant to test high-temperature water splitting in multiple thermochemical cycles. Using thermally-stabilized redox materials, particularly ferrites, already the team has documented reliable multiple-cycle results, sparking hope that sustainable hydrogen energy through the use of thermal hydro-splitting will one day be feasible, says Shende. Just two other US. locations, and possibly a third, are conducting similar research, according to Shende. One of the aspects that makes the Mines experiments unique is that the group has successfully split water molecules during multiple cycles at significantly lower temperatures than other documented research efforts. While others have demonstrated thermochemical splitting at 800-1,500°C, the School of Mines has documented multiple cycles at 700-1,100°C, which could potentially lead to a more affordable large-scale effort.

Mainz scientists create new flexible mineral inspired by deep-sea sponges

(YouTube) Scientists at Johannes Gutenberg University Mainz and the Max Planck Institute for Polymer Research in Germany have created a new synthetic hybrid material with a mineral content of almost 90 percent, yet extremely flexible. They imitated the structural elements found in most sea sponges and recreated the sponge spicules using the natural mineral calcium carbonate and a protein of the sponge. Natural minerals are usually very hard and prickly, as fragile as porcelain. Amazingly, the synthetic spicules are superior to their natural counterparts in terms of flexibility, exhibiting a rubber-like flexibility. The synthetic spicules can, for example, easily be U-shaped without breaking or showing any signs of fracture. This highly unusual characteristic, described by the German researchers in the current issue of Science, is mainly due to the part of organic substances in the new hybrid material. It is about ten times as much as in natural spicules. The synthetic material was self-assembled from an amorphous calcium carbonate intermediate and silicatein and subsequently aged to the final crystalline material. After six months, the synthetic spicules consisted of calcite nanocrystals aligned in a brick wall fashion with the protein embedded like cement in the boundaries between the calcite nanocrystals.

BBC: The ceramic used in bullet-stopping body armor

Ceramics could be the key to providing soldiers with lighter and more effective body armor, according to a British research team attracting interest from the Ministry of Defense. “Most people are familiar with ceramics in the house—your plates, mugs and possibly your toilet,” says material scientist Hywel Jones of Sheffield Hallam University. The ceramics he hopes to use in body armor are in some ways similar being hard, light and brittle, but they are specialized versions known as engineering or technical ceramics. Jones is working with Anthony Pick, a ceramics consultant to develop new armor materials. The work is being carried out by XeraCarb, a spin-out business created by Sheffield Hallam to take its technology into production. They have produced a low-density composite ceramic which is mainly silicon carbide. Its manufacture requires lower furnace temperatures than similar materials, making it more energy efficient and cheaper to produce.

Novel heating system could Improve electric car’s range: Prototype system can heat and cool without draining battery power.

(MIT Technology Review) Buyers considering an electric car must bear in mind that using battery-powered heating and air conditioning can decrease the car’s range by a third or more. But, a heating and cooling system being developed by researchers at MIT almost eliminates the drain on the battery. The researchers are working with Ford on a system that they hope to test in Ford’s Focus EV within the next two years. The work is being funded with a $2.7 million grant from the ARPA-E. The researchers describe their new device as a thermal battery. It uses materials that can store large amounts of coolant in a small volume. As the coolant moves through the system, it can be used for either heating or cooling. In the system, water is pumped into a low-pressure container, evaporating and absorbing heat in the process. The water vapor is then exposed to an adsorbant—a material with microscopic pores that have an affinity for water molecules. This material pulls the vapor out of the container, keeping the pressure low so more water can be pumped in and evaporated. This evaporative cooling process can be used to cool off the passenger compartment. As the material adsorbs water molecules, heat is released; it can be run through a radiator and dissipated into the atmosphere when the system is used for cooling, or it can be used to warm up the passenger compartment. The system requires very little electricity-just enough to run a small pump and fans to blow cool or warm air. Eventually the adsorbant can’t take in any more water, but the system can be “recharged” by heating the adsorbant above 200°C. This causes it to release the water, which is condensed and returned to a reservoir.

A look back: Four years with Dr. Chu

In honor of DOE Secretary Chu’s last day at the department, here’s a look back at his time overseeing important investments in science, innovation, and clean energy technologies that are making America more competitive and helping us win the race for a clean energy future. For more than four years, he has provided remarkable leadership in pursuing both President Obama’s nuclear security agenda as well as an all-of-the-above approach to energy that invests in clean energy, reduces our dependence on foreign oil, addresses the global climate crisis, and supports the clean energy jobs of the future.

2D germanium: Redesigned material could lead to lighter, faster electronics

The same material that formed the first primitive transistors more than 60 years ago can be modified in a new way to advance future electronics, according to a new study. Chemists at Ohio State University have developed the technology for making a one-atom-thick sheet of germanium, and found that it conducts electrons more than ten times faster than silicon and five times faster than conventional germanium. The material’s structure is closely related to that of graphene—a much-touted two-dimensional material comprised of single layers of carbon atoms. As such, graphene shows unique properties compared to its more common multilayered counterpart, graphite. Graphene has yet to be used commercially, but experts have suggested that it could one day form faster computer chips, and maybe even function as a superconductor, so many labs are working to develop it. Joshua Goldberger, assistant professor of chemistry at Ohio State, decided to take a different direction and focus on more traditional materials.In a paper published online in ACS Nano, he and his colleagues describe how they were able to create a stable, single layer of germanium atoms. In this form, the crystalline material is called germanane. Researchers have tried to create germanane before. This is the first time anyone has succeeded at growing sufficient quantities of it to measure the material’s properties in detail, and demonstrate that it is stable when exposed to air and water.

Share

Roll-to-roll coating of electrodes at Fraunhofer IWS: The scientists now have optimized the design of anode and cathode for lithium-sulfur batteries. Credit: Jürgen Leibmann.

A longer life for lithium-sulfur batteries

There are currently over 40 million cars on Germany’s roads. Only a fraction of them are powered by electric energy—around 6,400 vehicles. The comparatively short range of electric cars doesn’t help their popularity. An extremely promising avenue of research is the lithium-sulfur battery, which is significantly more powerful and less expensive than the better-known lithium-ion battery. Although their short lifespan has made them unsuitable for use in cars before now, this may be about to change in the foreseeable future. Scientists at the Fraunhofer Institute for Material and Beam Technology IWS in Dresden have developed a new design that increases the charge cycles of lithium-sulfur batteries by a factor of seven. “During previous tests, the batteries scarcely crossed the 200-cycle mark. By means of a special combination of anode and cathode material, we have now managed to extend the lifespan of lithium-sulfur button cells to 1,400 cycles,” says Holger Althues, head of the Chemical Surface Technology group at IWS, who is delighted with his team’s breakthrough. The anode of the team’s prototype is not made from the usual metallic lithium, but from a silicon-carbon compound instead. This compound is significantly more stable, as it changes less during each charging process than metallic lithium. The more the structure of the anode changes, the more it interacts with the liquid electrolyte, which is situated between the anode and the cathode and carries the lithium-ions.

ORNL leading study focused on afterlife of electric vehicle batteries

Once they’ve finished powering electric vehicles for hundreds of thousands of miles, it may not be the end of the road for automotive batteries, which researchers believe can provide continued benefits for consumers, automakers and the environment. Five used Chevrolet Volt batteries are at the heart of the Department of Energy Oak Ridge National Laboratory’s effort to determine the feasibility of a community energy storage system that would put electricity onto the grid. Over the next year, researchers from ORNL, General Motors and the ABB Group will conduct studies and compile data using a first-of-its-kind test platform officially commissioned today. ”With about one million lithium-ion batteries per year coming available from various automakers for the secondary market beginning in 2020, we see vast potential to supplement power for homes and businesses,” said Imre Gyuk, manager of the Energy Storage Research Program in DOE’s Office of Electricity Delivery and Energy Reliability. “Since these batteries could still have up to 80 percent of their capacity, they present a great opportunity for use in stationary storage devices before sending them to be recycled.”

Sensor for asteroid camera passes critical test

Scientists are testing a new sensor designed to be the eyes of a future asteroid-tracking mission. “The Near Earth Object Camera (NEOCam) sensor will increase our ability to detect hazardous asteroids near the Earth and improve our understanding of threatening objects,” says William J. Forrest, professor of astronomy at the University of Rochester. Once launched, the space-based telescope would be positioned at a location about four times the distance between Earth and the moon. From this lofty perch, NEOCam could observe the comings and goings of objects near Earth without the impediments to efficient observing like cloud cover and even daylight. Asteroids do not emit visible light, they reflect it, which can make it difficult to determine size using visible light telescopes. But asteroids always emit infrared radiation. Asteroids emit most of their radiation at infrared wavelengths near about 10 microns (0.0004 inches), which humans perceive as heat. There is also relatively less radiation from stars and galaxies at these wavelengths, which simplifies detection of faint moving objects. “This sensor works at higher temperatures than any other similar ones we have at the moment,” says Judith Pipher, emeritus professor in physics and astronomy at Rochester. “This means they can be passively cooled, making the instrument less heavy and less expensive to put into space.”

First Demonstration of the Storage And Release of Light in a Metamaterial

(MIT Technology Review) The ability to slow down and trap light has become a hot topic in physics since it was first observed in the 1990s. The ability to trap electromagnetic waves has important applications in areas such as information storage, sensing and quantum optics. But the field has not progressed quite as quickly as many had hoped. That’s largely because of the complexity of the experimental setup and the difficulty in releasing the waves with their original properties after they have been trapped. Recently, Toshihiro Nakanishi and pals at Kyoto University in Japan reveal a new approach to this problem that has the potential to bring the routine storage and release of electromagnetic waves closer to reality. Conventional light trapping relies on atoms such as cesium and rubidium that have special combinations of ground and excited states. These atoms absorb at one specific frequency. However by zapping them with a laser at another frequency, called a probe, that excites the atoms, light can then pass through. This phenomenon is called electromagnetically induced transparency. But there is another way to achieve this kind of trapping, say Nakanishi and co. Instead of a cloud of atoms, these guys have created a metamaterial but does the same job. In this case, Nakanishi and company have created a metamaterial in which each repeating unit contains two variable capacitors. One of the capacitors is designed to absorb and radiate waves at a particular frequency while the other is designed to trap them. If the capacitors are tuned to the same frequency, any light at that frequency is absorbed and trapped. Detuning the capacitors then releases the electromagnetic waves, allowing them to continue on their way.

Ultrasound signal reveals microstructure

(American Physical Society) As a steel girder or concrete slab ages, its internal microstructure may change and lead to catastrophic failure. A proposed technique for analyzing the noise in ultrasound signals, described in Physical Review E, could provide an early warning system. The method is an adaption of an analysis previously used to characterize DNA. In the new computer simulations, the technique was able to correctly identify a wide range of microstructures in a one-dimensional material. The flooding of a river or a stock market crash may seem unpredictable, but often these events have some hidden relation to the past. The level of the river may be more likely to go up if it went up the week before, for example. It’s as if these systems retain some memory of past fluctuations, rather than having totally independent fluctuations from one moment to the next. One of the mathematical techniques for identifying such long-term memory in seemingly random data is called detrended fluctuation analysis (DFA). It has been used in the study of long-range correlations in DNA sequences, heart rates, human stride lengths, and temperature records. DFA could also be useful in ultrasonic evaluation of materials. Engineers currently use the scattering of ultrasound signals in a material as a way to nondestructively test for cracks or other large-scale features. However, research in 2004 showed that DFA performed on ultrasound signals from a cast-iron sample could reveal the fractal nature of the microstructure. André Vieira of University of São Paulo in Brazil and his colleagues at the Federal University of Ceará in Brazil have now developed a more general DFA framework for ultrasound inspection.

Layered 2D nanocrystals promising new semiconductor

(R&D) Researchers are developing a new type of semiconductor technology for future computers and electronics based on “2D nanocrystals” layered in sheets less than a nanometer thick that could replace today’s transistors. The layered structure is made of a material called molybdenum disulfide, which belongs to a new class of semiconductors—metal di-chalogenides—emerging as potential candidates to replace today’s technology, complementary metal oxide semiconductors, or CMOS. New technologies will be needed to allow the semiconductor industry to continue advances in computer performance driven by the ability to create ever-smaller transistors. It is becoming increasingly difficult, however, to continue shrinking electronic devices made of conventional silicon-based semiconductors. “We are going to reach the fundamental limits of silicon-based CMOS technology very soon, and that means novel materials must be found in order to continue scaling,” says Saptarshi Das, who has completed a doctoral degree, working with Joerg Appenzeller, a professor of electrical and computer engineering and scientific director of nanoelectronics at Purdue’s Birck Nanotechnology Center. “I don’t think silicon can be replaced by a single material, but probably different materials will co-exist in a hybrid technology.” Findings show that the material performs best when formed into sheets of about 15 layers with a total thickness of 8 to 12 nanometers. The researchers also have developed a model to explain these experimental observations. “Our model is generic and, therefore, is believed to be applicable to any 2D layered system,” Das says. Molybdenum disulfide is promising in part because it possesses a bandgap, a trait that is needed to switch on and off, which is critical for digital transistors to store information in binary code.

Share

Nanowire crystals used as the solar cells. SEM image of GaAs nanowire crystal grown on a silicon substrate. Credit: Krogstrup et al., Niels Bohr Institute.

Nanowire solar cells raise efficiency limit

Scientists from the Nano-Science Center at the Niels Bohr Institute, Denmark, and the Ecole Polytechnique Fédérale de Lausanne, Switzerland, have shown that a single GaAs nanowire can concentrate the sunlight up to 15 times of the normal sun light intensity. These results demonstrate the great potential of development of nanowire-based solar cells, says Peter Krogstrup on the surprising discovery that is described in the journal Nature Photonics. In recent years, the research groups have studied how to develop and improve the quality of the nanowire crystals. It turns out that the nanowires naturally concentrate the sun’s rays into a very small area in the crystal by up to a factor 15. Because the diameter of a nanowire crystal is smaller than the wavelength of the light coming from the sun, it can cause resonances in the intensity of light in and around nanowires. Thus, the resonances can give a concentrated sunlight, where the energy is converted, which can be used to give a higher conversion efficiency. The typical efficiency limit—the so-called “Shockley-Queisser Limit”—is a limit, which for many years has been a landmark for solar cells efficiency among researchers, but now it seems that it may be increased.

Two new joint large-scale research projects at Mainz and Kaiserslautern to supply state-of-the-art technologies to businesses

Two €3.8 million research projects in materials science and spintronics have been initiated at Johannes Gutenberg University Mainz and the University of Kaiserslautern. The two new projects, STeP and TT-DINEMA, are designed to help speed up the process of conversion to marketable procedures and products. The purpose of the Spintronic Technology Platform in Rhineland-Palatinate (STeP) is to promote the sustained build-up of technical competencies and to support regional companies working in the spintronics sector. The platform has been specifically designed to bolster research into and the development of magnetic coating systems, which are particularly suitable for use in products such as sensors and memory storage units. At the core of the research being undertaken by STeP are so-called Heusler materials. The objective is to develop “building block systems” that can then be flexibly adapted to meet the wide range of different functional and technological challenges. The aim of the TT-DINEMA project is to establish an internationally competitive and independent service center that can provide original new material concepts. It represents the starting point for innovative development projects in various fields of applications, ranging from solar technology through medical technology to thermoelectrics, and is likely to be of particular benefit to small and medium-sized companies. Again, Heusler compounds are at the focus of attention concerning the applied materials. In addition to their broad application potential, these materials are also interesting from the commercial point of view because of their low cost, sustainability, environmental friendliness, and ease of processing.

New Sandia book highlights pressing need for hydrogen-powered vehicles

Sandia National Laboratories reveals the breadth of its hydrogen fuel expertise in the recently published Hydrogen Storage Technology—Materials and Applications. Sandia researcher Lennie Klebanoff is confident that the book’s content will give readers a sense of urgency about the need to get zero-emission hydrogen fuel cell vehicles on the road, and to get other hydrogen-based power equipment into the marketplace. Klebanoff, who serves as the book’s editor and cowrote half the chapters, knows his topic well. He was director of the Metal Hydride Center of Excellence, one of three DOE Hydrogen Storage Centers of Excellence dedicated to solving the problem of storing hydrogen on automobiles. This Center, competitively selected and funded through DOE’s Office of Energy Efficiency and Renewable Energy, included 21 partners from industry, academia, and national laboratories from 2005 through 2010. Klebanoff himself said storage isn’t the technical hurdle some believe it to be. “We actually make the argument that storage is not a huge barrier,” he says. “All of the major car manufacturers have produced hydrogen vehicles, and they can all run for at least 240 miles, and in one case, even up to 430 miles.” He acknowledged that the research community must work harder to meet the government and industry consumer vehicle target of at least 300 miles across a range of vehicle types and sizes. “However, there is no technical hydrogen storage barrier preventing the roll-out of the first hydrogen-powered vehicles today,” Klebanoff asserts.

Holes in silicon hold on to their spin

Spintronic devices are almost exclusively fabricated out of n-type semiconductors as opposed to p-type semiconductors, which may seem surprising since both electrons and holes have spin. The reason is that holes have been assumed to be unable to preserve their spin polarization over distances longer than a few tens of nanometers. This perspective is changing, as several recent experiments have shown that hole spins in p-type silicon can be polarized and retain their polarization for a surprisingly long time. However, experiments that directly probe the spin of the holes as they travel through the material have been lacking. Eiji Shikoh at Osaka University, Japan, and colleagues have now performed such an experiment. Writing in Physical Review Letters, Shikoh et al. use a new approach to show that holes in p-type silicon can preserve spin-based information and transport it over distances much longer than previously thought. Taken together, the new work and the previous experiments support the view that spin transport is realistic in p-type semiconductors. This opens the door to developing spintronic devices and circuits that exploit the unique features of p-type semiconductors and their combination with n-type materials.

Laser-based glass soldering packages temperature-sensitive glass/glass and glass/ceramics

(Laser Focus World) To package temperature-sensitive glass/glass and glass/ceramics components, especially those with large substrate surfaces to be sealed, a laser-based joining process that uses glass solder is becoming more and more significant. The Fraunhofer Institute for Laser Technology (ILT) is developing the appropriate irradiation strategies and processing heads to achieve this. The advantage of the laser-based joining process is that the laser beam is able to apply energy to a limited space in order to melt the glass solder precisely, thus generating a bond with long-term, stable hermeticity. In laser-based glass soldering, the laser beam is guided over the workpiece and applies the energy solely into the glass solder itself to melt it. One radiation approach for this is quasi-simultaneous laser soldering, but it is technically restricted by the maximum processing field size of the focusing optics, and is also limited, from an economic point of view, by the laser power required. In ILT’s new approach is “contour soldering with energy input adapted laterally to feed movement” that enables large substrates to be joined at significantly lower laser power. For contour soldering, continuous-beam sources run at a power of less than 100 W, independent of the substrate sizes to be joined.

New NIST microscope measures nanomagnet property vital to spintronics

Researchers at NIST have developed a new microscope able to view and measure an important but elusive property of the nanoscale magnets used in an advanced, experimental form of digital memory. The new instrument already has demonstrated its utility with initial results that suggest how to limit power consumption in future computer memories. NIST’s heterodyne magneto-optic microwave microscope, or H-MOMM, can measure collective dynamics of the electrons’ spins-the basic phenomenon behind magnetism-in individual magnets as small as 100 nanometers in diameter. “The measurement technique is entirely novel, the capability that it has enabled is unprecedented, and the scientific results are groundbreaking,” project leader Tom Silva says. As described in a new paper, NIST researchers used the H-MOMM to quantify, for the first time, the spin relaxation process-or damping-in individual nanomagnets. Spin relaxation is related to how much energy is required to switch a unit of spintronic memory between a 0 and a 1. The nanomagnets used in experimental spintronic systems are too big to yield their secrets to conventional atomic physics tools yet too small for techniques used with bulk materials. Until now, researchers have been forced to measure the average damping from groups of nanomagnets. The new microscope enabled NIST researchers to study, in detail, the ups and downs of spin excitation in individual magnets made of a layer of a nickel-iron alloy on a sapphire base.

Glass-blowers at a nanoscale

Have you ever thrown into the fire—even if you shouldn’t have—an empty packet of crisps? The outcome is striking: the plastic shrivels and bends into itself, until it turns into a small crumpled and blackened ball. This phenomenon is explained by the tendency of materials to pick up their original features in the presence of the right stimulus. Hence, this usually happens when heating materials that were originally shaped at high temperatures and cooled afterwards. EPFL researchers realized that this phenomenon occurred to ultrathin quartz tubes (capillary tubes) under the beam of a scanning electron microscope. “This is not the original microscope’s purpose. The temperature increase is explained by an accumulation of electrons in the glass. Electrons accumulate because glass is a non-conductive material,” explains Lorentz Steinbock, researcher at the Laboratory of Nanoscale Biology and co-author of a paper on this subject published in Nano Letters. As the glass shrinks, it can be seen live on the microscope screen. “It’s like a glass-blower. Thanks to the possibilities provided by the new microscope at EPFL’s Center of Micronanotechnology, the operator can adjust the microscope’s voltage and electric field strength while observing the tube’s reaction. Thus, the person operating the microscope can very precisely control the shape he wants to give to the glass”, says Aleksandra Radenovic, tenure-track assistant professor in charge of the laboratory. At the end of this process, the capillary tube’s ends are perfectly controllable in diameter, ranging from 200 nanometers to fully closed.

Share