Other materials stories that may be of interestPublished on May 14th, 2013 | By: Eileen De Guire
University of Manchester and National University of Singapore researchers have shown how building multi-layered heterostructures in a three-dimensional stack can produce an exciting physical phenomenon exploring new electronic devices. The breakthrough, published in Science, could lead to electric energy that runs entire buildings generated by sunlight absorbed by its exposed walls; the energy can be used at will to change the transparency and reflectivity of fixtures and windows depending on environmental conditions, such as temperature and brightness. Collectively, such 2D crystals demonstrate a vast range of superlative properties: from conductive to insulating, from opaque to transparent. Every new layer in these stacks adds exciting new functions, so the heterostructures are ideal for creating novel, multifunctional devices. The Manchester and Singapore researchers expanded the functionality of these heterostructures to optoelectronics and photonics. By combining graphene with monolayers of transition metal dichalcogenides (TMDC), the researchers were able to created extremely sensitive and efficient photovoltaic devices. Such devices could potentially be used as ultrasensitive photodetectors or very efficient solar cells. In these devices, layers of TMDC were sandwiched between two layers of graphene, combining the exciting properties of both 2D crystals. TMDC layers act as very efficient light absorbers and graphene as a transparent conductive layer. This allows for further integration of such photovoltaic devices into more complex, more multifunctional heterostructures.
A shattered windshield has a story to tell. The key to hearing it is counting the cracks. The number of cracks that emerge in a plate of glass or Plexiglas relates to the speed of the object that broke it, researchers demonstrate in Physical Review Letters. This simple relationship could prove useful for forensic scientists, archaeologists and even astronomers. Over the past century, most research into cracks has focused on parameters that determine whether a material remains intact when struck. Nicolas Vandenberghe and his colleagues at Aix-Marseille University in France decided to try something different: They wanted to push glass and other materials past their breaking points and study the resulting fractures. They wondered if they could connect the patterns of cracks to the properties of the impact that created them, something no one had done before, Vandenberghe says. So he and his team set up a shooting gallery. Knowing that cracks emerge within a matter of microseconds of impact, Vandenberghe employed a high-speed camera to capture the instant of collision. The photographic evidence revealed a clear connection: After taking into account the type of material and its thickness, the number of cracks doubled for every fourfold increase in the ball’s speed. For example, a 70-kph pellet caused an average of four cracks in 1-millimeter-thick Plexiglas plates, while a 280-kph one made eight.
Though they be but little, they are fierce. The most powerful batteries on the planet are only a few millimeters in size, yet they pack such a punch that a driver could use a cellphone powered by these batteries to jump-start a dead car battery—and then recharge the phone in the blink of an eye. Developed by researchers at the University of Illinois at Urbana-Champaign, the new microbatteries out-power even the best supercapacitors and could drive new applications in radio communications and compact electronics. “This is a whole new way to think about batteries,” says William P. King, a Bliss Professor of mechanical science and engineering. “A battery can deliver far more power than anybody ever thought. In recent decades, electronics have gotten small. The thinking parts of computers have gotten small. And the battery has lagged far behind. This is a microtechnology that could change all of that. Now the power source is as high-performance as the rest of it.” With currently available power sources, users have had to choose between power and energy. For applications that need a lot of power, like broadcasting a radio signal over a long distance, capacitors can release energy very quickly but can only store a small amount. For applications that need a lot of energy, like playing a radio for a long time, fuel cells and batteries can hold a lot of energy but release it or recharge slowly.
Professor Jeremy Kilburn (vice-principal for science and engineering) and Professor Martin Dove (director) launched the new Materials Research Institute at Queen Mary, University of London, on April 15, 2013. The afternoon consisted of talks from Queen Mary academics and internationally-acclaimed experts, who presented recent developments in the area of materials research. The talks were followed by a reception held in the Queens’ Building Senior Common Room, and provided an opportunity for informal discussion and networking. The launch was a success, which received excellent feedback from visitors and colleagues.
In Kanpur, India, Defense Materials and Stores Research and Development (DMSRDE), a unit of Defense Research and Development Organization (DRDO), has been working in frontier area of non-matellic materials. To celebrate DRDO Technology Day, DMSRDE organised an open house for the students to show their products and technologies abilities. Around 500 students, along with their teachers from different schools, came to DMSRDE on this occasion to see the exhibition. The students therein saw different defense-related product, such as bullet proof jackets, coils used in the bofors gun, camouflage and stealth materials etc. DMSRDE is working in very important area of material development for high temperature structural applications. It has developed capabilities to produce the polycorbosilane precursor materials which are used in production of silicon carbide based strategic products. This material in turn can also be converted to high heat resistance silicon carbide fibers for composite development which have enormous applications in defence, atomic energy, and aerospace industries. It can withstand temperature between 1,500–2,000°C. These materials were displayed in the exhibition.
The possible future restrictions to the supply of critical materials have been the subject of debate for several years. In response to these an international consortium has been brought together to develop new solutions to the European requirement for rare earth metals. Remanence is an ambitious program designed to dramatically increase the amount of rare earth materials recovered and remanufactured from existing waste streams. The project brings together European industry and academia across the supply chain to develop the innovative technologies, business models and market information required to exploit this valuable resource reducing dependence on primary sources. The partners will develop new and innovative processes for the recovery and recycling of neodymium iron boron magnets (NdFeB) from a range of waste electronic and electrical equipment (WEEE). Advanced sensing and mechanical separation techniques will be developed in combination with innovative processes to recover the rare earth magnets in the WEEE. Remanence brings together Europe’s leading experts in sensing, disassembly, recycling technology and materials processing in a multi-disciplinary project able to deliver significant technical advances. C-Tech Innovation Ltd will lead a consortium including University of Birmingham, Stena Technoworld AB, ACREO Swedish ICT AB, Leitat Technological Centre, OptiSort AB, Chalmers Industriteknik, Magneti Ljubljana and Kolektor Magnet Technology GMBH.
(MIT Technology Review) A new generation of engines being developed by the world’s largest jet engine maker, CFM (a partnership between GE and Snecma of France), will allow aircraft to use about 15 percent less fuel-enough to save about $1 million per year per airplane and significantly reduce carbon emissions. The first of these new engine, called LEAP, will feature a technology that has never been used in a large-scale production jet engines before: ceramic composite materials that weigh far less than the metal alloys they’ll replace and can endure far higher temperatures. The engine will also make use of parts produced through 3D printing, a new kind of manufacturing that can produce complex shapes that would be difficult or impossible to make with conventional manufacturing techniques. These technologies could eventually be used to make more parts of the engine, leading to further advances in efficiency, says Gareth Richards, LEAP program manager for GE Aviation.
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