Other materials science stories that may be of interestPublished on August 7th, 2012 | By: email@example.com
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(Futurity) Five years after the deadly I-35W bridge collapse in Minneapolis, advances in sensors are making warning systems more affordable and practical. A new generation of these devices is needed to adequately monitor the nearly 150,000 US highway bridges, about one-in-four listed by the federal government as either “structurally deficient” or “obsolete,” say researchers at the University of Maryland. “We no longer need to roll the dice when it comes to the structural integrity of the nation’s highway bridges,” says engineer Mehdi Kalantari. “Technical advances in wireless sensors make real-time monitoring both affordable and practical.” Kalantari leads one of two engineering teams developing a system of tiny, long-lasting, energy-efficient, low-maintenance wireless sensors, along with software that analyzes real-time data collected. Another University of Maryland engineering team is working on a total “smart bridge” package with multiple technology innovations. While the system is not yet available commercially, key elements are being tested by Maryland State Highway officials, the Maryland Transportation Authority, and the North Carolina Department of Transportation.
(GizMag) Chimera Energy Corporation of Houston, Texas, has announced that they are licensing a new method for extracting oil and gas from shale fields that doesn’t contaminate ground water resources because it uses exothermic reactions instead of water to fracture shale. Some fracking engineers prefer non-hydraulic methods. One of these, used recently in New York State, swaps the water for gelled propane. The idea being that the propane reverts to a gas at the end of the process and can be pumped out, leaving any additives behind in the well, much like boiling seawater and leaving behind the salt. Chimera Energy uses what is called “dry fracturing” or “exothermic extraction.” First developed in China, this involves using hot gases rather than liquid to fracture the shale. In dry fracturing, metal oxides, ultraexpansive evaporants and pumice are pumped into the well. The metal oxides react with one another to form an exothermic reaction. Extremely hot gases are generated that expand and crack the shale. Meanwhile, the pumice shoots in and reinforces the fractures, keeping them from closing and allowing the gas or oil to flow. Chimera Energy claims that not only is the technique environmentally safe, but that it is compatible with any existing well in the world.
Scientists are reporting development of a new transparent solar cell, an advance toward giving windows in homes and other buildings the ability to generate electricity while still allowing people to see outside. Their report appears in the journal ACS Nano. Yang Yang, Rui Zhu, Paul S. Weiss and colleagues explain that there has been intense world-wide interest in so-called polymer solar cells, which are made from plastic-like materials. They describe a new kind of PSC that produces energy by absorbing mainly infrared light, not visible light, making the cells 66 percent transparent to the human eye. They made the device from a photoactive plastic that converts infrared light into an electrical current. Another breakthrough is the transparent conductor made of a mixture of silver nanowire and titanium dioxide nanoparticles, which was able to replace the opaque metal electrode used in the past. This composite electrode also allowed the solar cell to be fabricated economically by solution processing. The authors suggest the panels could be used in smart windows or portable electronics.
(Green Car Congress) The Nikkei reports that joint ventures being planned by Japan-based TDK Corp. and Hitachi Metals Ltd. to make powerful magnets in China have foundered due to Japanese regulations that will complicate the necessary exports and technology transfers. In essence, the projects have been caught in the trade diplomacy crossfire over Chinese restrictions on exports of rare-earth metals, which are vital for making powerful magnets. The longer the dispute rages, the greater the chance of trouble for production of hybrid cars and other items containing these magnets.
A Yale-led team of mineral physicists has for the first time confirmed through high-pressure experiments the structure of cold-compressed graphite, a form of carbon that is comparable in hardness to its cousin, diamond, but only requires pressure to synthesize. The researchers believe their findings could open the way for a super hard material that can withstand great force and can be used – as diamond-based materials are now – for many electronic and industrial applications. Under normal conditions, pure carbon exhibits vastly different physical properties depending on its structure. For example, graphite is soft, but diamond is one of the hardest materials known. Graphite conducts electricity, but diamond is an insulator. In the middle is the form of carbon confirmed by the Yale-led team, dubbed M-carbon and predicted by theoretical methods initially in 2006. M-carbon is made when graphite is compressed to pressures approximately 200,000 times room pressure, at room temperature. Researchers say this intermediate structure has much lower symmetry than diamond, but is as hard. In fact, “Our study shows that M-carbon is extremely incompressible and hard, rivaling the extreme properties of diamond so much that it damages diamond,” says principal investigator Kanani K.M. Lee, assistant professor of geology and geophysics at Yale.
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