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Nanotechnology To Improve Solar Cells
Researchers at the NanoPower Research Labs at Rochester Institute of Technology, led by director Ryne Raffaelle, are using nanotechnology to explore this possibility through a project funded by an $847,109 grant from the U.S. Department of Defense. The project aims to take current state-of-the-art solar cells used for space power to the next level by developing nanostructured materials and, ultimately, by producing nanostructured cells. The program may extend to three and half years, with total funding reaching $3 million. "If successful, the results of this program will improve current solar array and satellite technology, and lay the foundation for long-term improvement in our ability to use solar energy," Raffaelle says. Unique to this project is the ability to exploit the fundamental behavior of nanoscale crystals, also known as quantum dots, which alter the way a solar cell absorbs light and converts it into electricity. As per Raffaelle, the electrical, optical, mechanical and even thermal properties of nanomaterials can be controlled by changing the particle size, making them highly useful in semiconductor device development. Today's current solar-cell technology used for space power relies upon three individual photovoltaic junctions used in a series. These so-called triple-junction solar cells-consisting of the chemical compounds, germanium, gallium arsenide and indium gallium phosphide-are grown latticed-matched on top of one another. Raffaelle's team will augment the middle cell in the three-layered sandwich with a quantum dot array to enhance its short-circuit current and improve the overall efficiency of the triple junction cell......... Posted by: Kevin Permalink Source Identifying Gems And Minerals
Downs is almost halfway there. So far, the associate professor of geosciences at The University of Arizona in Tucson has cataloged about 1,500 of the approximately 4,000 known minerals using a technique called Raman spectroscopy. The effort is known as the RRUFF Project. "We're developing a tricorder," Downs said, referring to the instrument used on the "Star Trek" television show that could be waved over materials to identify their chemical composition. Downs' work is destined for space. Eventhough Downs' current Raman spectrometer takes up an area the size of a tabletop, his colleague M. Bonner Denton, a UA professor of chemistry and of geosciences, is developing a pocket-sized Raman spectrometer to be used on the 2009 Mars rover. Downs is collaborating with George Rossman of the California Institute of Technology in Pasadena to develop the database of minerals. The technology being developed for Mars will help create handheld instruments for use on Earth. One use for a hand-held instrument would be the identification of gemstones. Downs and Denton will both give presentations on that aspect of the project on Sunday afternoon, March 12, at the 57th Annual Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy (PITTCON 2006)......... Posted by: Sarah Permalink Source Enceladus Is The Source Of Saturn's E-ring
Writing in the journal Science, researchers show how a plume of icy water vapour bursting out of the South Pole of Enceladus replenishes the water particles that make up the E-ring and creates a dynamic water-based atmosphere around the small moon. The E-ring is Saturn's outermost ring and is composed of microscopic particles. It is very diffuse and stretches between the orbit of two of Saturn's moons, Mimas and Titan. Researchers discovered the dynamic atmosphere during three separate fly-bys of Enceladus by the Cassini spacecraft in February, March and July 2005. Cassini Huygens is a joint NASA/ESA mission to study the Saturnian system. The team working on results from the magnetometer instrument were surprised to discover what they believed was an atmosphere on their first fly-by, 1176km from the moon's surface. After a second flyby at 500km confirmed their observations, they persuaded the Cassini Project to take the next flyby much closer to Enceladus in order to investigate further. On this flyby, at 175km, measurements from all the different instruments on the spacecraft confirmed the presence of an atmosphere. Later remote sensing observations of the moon revealed a plume of water vapour coming from the moon's South Pole......... Posted by: Brooke Permalink Source Measuring Geysers Of Enceladus
Announced by the Cassini Imaging Science Team in today's issue of Science, the theory is bolstered by measurements from the Cassini Plasma Spectrometer (CAPS), as published in the same issue by a team led by Robert Tokar of Los Alamos National Laboratory. CAPS was partly designed and built at Los Alamos. "During the July 14 close flyby we began getting signatures, far from Enceladus, of water ejection. From the deflections we could measure of the ionized gas in the magnetosphere, it was erupting at 100 kg per second (220 lbs per second), and the data are consistent with measurements from the spacecraft's other instruments. It is actual H20 molecules," said Tokar. Enceladus is a small moon, but highly reflective due to the fresh layer of snow and ice on its surface. Tokar suggests that the icy geysers at the south pole, erupting from a series of cracks, are pumping a continuous flow of water particles into the area above the moon. Much of the material falls back to the surface as snow......... Posted by: Brooke Permalink Mass Extinctions - A Threat from Outer Space?
University of Leicester geologists, Professor Andy Saunders and Dr Marc Reichow, are taking a fresh look at what may actually have wiped out the dinosaurs 65 million years ago and caused other similarly cataclysmic events, aware they may end up exploding a few popular myths. The idea that meteorite impacts caused mass extinctions has been in vogue over the last 25 years, since Louis Alverez's research team in Berkeley, California published their work about an extraterrestrial iridium anomaly found in 65-million-year-old layers at the Cretaceous-Tertiary boundary. This anomaly only could be explained by an extraterrestrial source, a large meteorite, hitting the Earth and ultimately wiping the dinosaurs - and a number of other organisms - off the Earth's surface. Professor Saunders commented: "Impacts are suitably apocalyptic. They are the stuff of Hollywood. It seems that every kid's dinosaur book ends with a bang. But are they the real killers and are they solely responsible for every mass extinction on earth? There is scant evidence of impacts at the time of other major extinctions e.g., at the end of the Permian, 250 million years ago, and at the end of the Triassic, 200 million years ago. The evidence that has been found does not seem large enough to have triggered an extinction at these times"......... Posted by: William Permalink Source Making Cleaner Gasoline
The Delft-based PhD student Xander Dupain has investigated a method which produces cleaner petrol using the method of 'catalytic cracking'. Catalytic cracking, with a worldwide processing capacity of over 500 million tonnes of oil per year, is one of the most important processes applied in modern oil refineries and the prime method for making petrol from oil. In addition it is an important way of producing diesel blends and valuable products such as propene and butene. The disadvantage of catalytic cracking is that a further expensive process (hydrotreatment) is often mandatory to render the petrol and diesel sufficiently clean and bring it into line with the necessary specifications. The core of Dupain's method is a combination of catalytic cracking with the Fischer-Tropsch Synthesis process. This chemical process was invented in the 1920s by the German scientists Franz Fischer and Hans Tropsch and further developed in Gera number of during the Second World War for the production of synthetic fuels from coal. Due to the relatively low oil prices in the period following the Second World War this method then mostly went out of fashion, with the exception of South Africa where - prompted by the international oil embargo - it was applied by the Sasol company to meet fuel demands. In recent years, as oil prices rise, the process has been experiencing a revival: with the activities of Shell in Malaysia and Qatar, for instance. It is now primarily being applied to obtain relatively clean synthetic diesel from natural gas and to make a series of other products which contain extremely low concentrations of sulphur, nitrogen and aromatics. Dupain believes it can be economically and environmentally interesting to catalytically crack the fairly 'heavy' faction (waxes) which is created by the Fischer-Tropsch Synthesis process. At the moment this cracking is still done using expensive hydrocracking that focuses mainly on the production of diesel and that also involves high consumption of hydrogen......... Posted by: Kevin Permalink Source Yellowstone's Deep Secret
The rim of the Yellowstone Caldera.
Credits: http://www.yellowstonegis.utah.edu/home/home.html
Using Synthetic Aperture Radar Interferometry, InSAR for short, Charles Wicks, Wayne Thatcher and other U.S. Geological Survey (USGS) researchers mapped the changes in the northern rim of the caldera, or crater, and discovered it had risen about 13 centimetres from 1997 to 2003. InSAR, a sophisticated version of 'spot the difference', involves mathematically combining different radar images, acquired from as near as possible to the same point in space at different times, to create digital elevation models and reveal otherwise undetectable changes occurring between image acquisitions. "We know now how mobile and restless the Yellowstone caldera actually is. Ground-based measurements can be more efficiently deployed because of our work," Thatcher said. "The research could not have been done without satellite radar data." . About 640,000 years ago, a massive volcano erupted in Yellowstone, creating the caldera, which measures some 45 kilometres wide and 75 kilometres long, in the centre of Yellowstone National Park......... Posted by: Tyler Permalink Source Ice Sheet Melting And Rapid Climate Changes
The study, which will be published Friday in the journal Science by scientists from Oregon State University, shows that ice sheets can react quite differently depending on the climatic conditions at the time global warming occurs - sometimes actually growing larger and sometimes rapidly disappearing, depending on whether increased snow offsets melting effects, or not. In this analysis of the Scandinavian Ice Sheet that existed as recently as 10,000 years ago, the study showed that it actually grew for a long period while the climate was warming but still very cold, and then rapidly disintegrated once the climate warmed even further. OSU experts say those same forces are at work today, and probably mean that in the face of future global warming, the ice in large parts of Antarctica may actually increase, while the massive Greenland ice sheet - which exists in a slightly warmer setting - will almost certainly disappear. "This study supports what we've been learning about the Greenland ice sheet, which is that it will completely melt within 500 to 1,000 years," said Peter Clark, a professor of geosciences at OSU and an international expert in the study of ancient ice sheets. "Our new analysis of the ancient Scandinavian Ice Sheet, like other studies, is showing how these events unfolded in the past, which will help us better understand what the future will hold."........ Posted by: Tyler Permalink Source No Stone Unturned For Female Salmon
For decades ecologists have believed that salmon nest-digging triggered only local effects. But a University of Washington researcher writes in this month's BioScience journal that the silt, minerals and nutrients that are unleashed have ecosystemwide effects, causing changes in rivers and lakes far from the nests. From decreasing the amount of algae there is to eat to possibly influencing when aquatic insects emerge, spawning salmon can be extraordinary "environmental engineers," says Jonathan Moore, a UW graduate student in aquatic and fishery sciences. Ignoring this role can cause missteps in managing salmon runs or attempting to rehabilitate habitat, he says. A major loss in the number of salmon, for example, doesn't just affect future generations of that fish alone. "In streams with high densities of salmon, the disturbance from spawning impacts virtually all aspects of stream ecology," he says. The female salmon, of course, isn't concerned about all that. She simply wants to lay her eggs in a nice, gravel-bottom bowl that's free of fine sediments that can smother them......... Posted by: Ashley Permalink Source Stronger Storms Change Heat and Rainfall
The mid-latitudes extend from the subtropics (approximately 30 degree N and S) to the Arctic Circle (66 degree 30" N) and the Antarctic Circle (66 degree 30" S) and include pieces of all of the continents with the exception of Antarctica. George Tselioudis and William B. Rossow, both researchers at NASA's Goddard Institute for Space Studies (GISS) and Columbia University, New York, authored the study that appears in the recent issue of the American Geophysical Union's journal, Geophysical Research Letters. "There are consequences of having fewer but stronger storms in the middle latitudes both on the radiation and on the precipitation fields," Tselioudis said. Using observations from the International Satellite Cloud Climatology Project (ISCCP) and the Global Precipitation Climatology Project (GPCP), Tselioudis and Rossow determined how the changes in intensity and frequency of storms are both cooling and warming the atmosphere around the world......... Posted by: Tyler Permalink |
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