Chemistry

Wed 25 Apr 2012 Chemists explain the molecular workings of promising fuel cell electrolyte. Researchers reveal how protons move in phosphoric acid sheds new light on the workings of a promising fuel cell electrolyte. Phosphoric acid fuel cells were the first modern fuel cell types to be used commercially and have found application as both stationary and automotive power sources. Their high efficiency as combined power and heat generators make them attractive targets for further development. In the cell, phosphoric acid functions as the medium (or "electrolyte") that transports protons produced in the reaction that decomposes the fuel across the cell. Indeed, phosphoric acid has the highest proton conductivity of any known substance, but what makes it work so well as a proton conductor has remained a mystery. Efficient proton transport across a fuel cell is just one of several technical challenges that must be tackled before this technology can be applied on a massive scale. The key to this problem is the identification of a suitable electrolyte material. Hydrated polymers are often employed, but these must operate at temperatures below the boiling point of water, which limits their utility. Phosphoric acid fuel cells and other phosphate-based cells, by contrast, can be operated at substantially higher temperatures. Chemists have sought a molecular level understanding of proton conduction phenomena for more than 200 years. The earliest studies concerned water and can be traced back to a landmark paper in 1806 by the German chemist Theodor von Grotthuss. more

  Geology

Thu 5 Apr 2012 For the first time, instrumentation aboard two NASA missions operating from complementary vantage points watched as a powerful solar storm spewed a two million-mile-per-hour stream of charged particles and interacted with the invisible magnetic field surrounding Earth. The storm, observed two years ago on April 5, 2010, also is thought to have caused an important communications satellite, Galaxy-15, to founder and drift, taking almost a year to return to its station. Understanding how solar events develop and impact satellites is like understanding the processes that cause extreme weather events on Earth to develop and destroy homes and businesses. more

  Energy

Thu 29 Mar 2012 A new dimension for solar energy. Innovative 3-D designs can more than double the solar power generated from a given area. Intensive research around the world has focused on improving the performance of solar photovoltaic cells and bringing down their cost. But very little attention has been paid to the best ways of arranging those cells, which are typically placed flat on a rooftop or other surface, or sometimes attached to motorized structures that keep the cells pointed toward the sun as it crosses the sky. So far, individual 3-D toweres has been modeled. A next step is to study a collection of such towers, accounting for the shadows that one tower would cast on others at different times of day. In general, 3-D shapes could have a big advantage in any location where space is limited, such as flat-rooftop installations or in urban environments, they say. Such shapes could also be used in larger-scale applications, such as solar farms, once shading effects between towers are carefully minimized.more

  Physics

Tue 20 Mar 2012 Ultracold experiments heat up quantum research. Physicists have experimentally demonstrated for the first time that atoms chilled to temperatures near absolute zero may behave like seemingly unrelated natural systems of vastly different scales, offering potential insights into links between the atomic realm and deep questions of cosmology. This ultracold state, called “quantum criticality,” hints at similarities between such diverse phenomena as the gravitational dynamics of black holes or the exotic conditions that prevailed at the birth of the universe. The results could even point to ways of simulating cosmological phenomena of the early universe by studying systems of atoms in states of quantum criticality. more