Other materials science stories that may be of interestPublished on June 26th, 2012 | By: email@example.com
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Engineers at the University of Wisconsin-Milwaukee have identified a catalyst that provides the same level of efficiency in microbial fuel cells as the currently used platinum catalyst, but at 5% of the cost. Since more than 60% of the investment in making microbial fuel cells is the cost of platinum, the discovery may lead to much more affordable energy conversion and storage devices. The material—nitrogen-enriched iron–carbon nanorods—also has the potential to replace the platinum catalyst used in hydrogen-producing microbial electrolysis cells, which use organic matter to generate a possible alternative to fossil fuels.
Japanese and US physicists are offering new details this week in the journal Nature regarding intriguing similarities between the quirky electronic properties of a new iron-based high-temperature superconductor and its copper-based cousins. While investigating a recently discovered iron-based HTS, the researchers found that its electronic properties were different in the horizontal and vertical directions. This electronic asymmetry was measured across a wide range of temperatures, including those where the material is a superconductor. The asymmetry was also found in materials that were “doped” differently. One feature that has been found in both compounds is electronic asymmetry—properties like resistance and conductivity are different when measured up and down rather than side to side. This asymmetry, which physicists also call “nematicity,” has previously been found in both copper-based and iron-based high-temperature superconductors, and the new study provides the strongest evidence yet of electronic nematicity in HTSs. In the study, the researchers used the parent compound barium iron arsenide, which can become a superconductor when doped with phosphorus.
(Gizmag) High-radiation environments are a silicon microchip’s worst nightmare and even state-of-the-art radiation-shielded circuits can fry after just a couple hours of exposure. Now engineers at the University of Utah have come up with a micro-electromechanical system that could be used to build robots and computers that are impervious to such conditions and may help us deal with high bursts of space radiation, damaged nuclear power plants or even the aftermath of a nuclear attack. The MEMS developed at the University of Utah don’t have this problem because they do away with semiconductor channels altogether. Instead, each device has two tungsten electrodes separated by a very narrow gap. When charged, the electrodes attract each other and touch, allowing the current to flow.
(Gizmag) Scientists from the University of Maryland and nearby Towson University have crammed 25,000 tiny “invisibility cloaks” onto a gold sheet, which itself only measures 25 millimeters per side. The researchers began with a commercially-available microlens array, consisting of a sheet of miniature optical lenses—each individual lens is just 30 micrometers in diameter. One side of this array was coated with a gold film. The array was then placed gold-side-down onto a glass slide, which had also been cover with gold, to create a double gold layer on the bottom. The optical qualities of the microlenses are such that when light strikes them, it is bent away from a spot in the middle of each lens—essentially, because light cannot strike it and reflect back off, this renders that middle section invisible. As the light is instead diverted around the sides of each circular lens, it is forced through the narrow gaps between the lenses.
(New York Times) The Westinghouse Electric Co. has lined up Ameren, a St. Louis-based electric company, as a partner for its small modular reactor project. Getting a strong indication of commercial interest is critical because the Nuclear Regulatory Commission can review only a few of the many proposed reactor designs and gives priority in the licensing process to those with a stronger chance of getting built. Some utility analysts have argued that small reactors would be good “drop-in replacements” for 1950s and 1960s-era coal plants that are now being retired, given that that their generating capacity would be about the same. But Ameren is looking at its Callaway nuclear plant near Fulton, Mo., where it runs one reactor and had hoped to build a second full-size one. That would be a multibillion-dollar project, however, and the Missouri state legislature refused to allow Ameren to bill customers for construction costs. So now it is now interested in a plant that is supposed to cost far less, although the companies did not give a price estimate in their announcements.
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