Monday, September 29, 2008

Energy policy: Renewable jet fuel From The Environmental News Network: "The Energy & Environmental Research Center (EERC) at the University of North Dakota has achieved a major technical milestone in creating a 100% renewable domestic fuel that meets the JP-8 aviation fuel screening criteria, proving a pathway to providing energy security to the U.S. military and the entire nation. "The technology takes advantage of feedstock chemistry to reduce capital and operating expenses. The feedstock-flexible process can use various crop oils and waste greases. The process can be tailored to produce combinations of propane, gasoline, jet fuel, and diesel that are identical to petroleum-derived fuels, enabling direct substitution with existing fuels and providing renewable options across the spectrum of fuel needs." "cc" 6:34:27 PM     Noctilucent clouds Here's the latest on noctilucent clouds from Science Blog. From the article: An explanation for a strange property of noctilucent clouds--thin, wispy clouds hovering at the edge of space at 85 km altitude--has been proposed by an experimental plasma physicist at the California Institute of Technology (Caltech), possibly laying to rest a decades-long mystery. Noctilucent clouds, also known as night-shining clouds, were first described in 1885, two years after the massive eruption of Krakatoa, a volcanic island in Indonesia, sent up a plume of ash and debris up to 80 km into Earth's atmosphere. The eruption affected global climate and weather for years and may have produced the first noctilucent clouds... Twenty-five years ago, researchers at Poker Flat, Alaska, discovered that the clouds were highly reflective to radar. This unusual property has long puzzled scientists. Bellan, reporting in the August issue of the Journal of Geophysical Research-Atmospheres, now has an explanation: the ice grains in noctilucent clouds are coated with a thin film of metal, made of sodium and iron. The metal film causes radar waves to reflect off ripples in the cloud in a manner analogous to how X-rays reflect from a crystal lattice. Sodium and iron atoms collect in the upper atmosphere after being blasted off incoming micrometeors. These metal atoms settle into a thin layer of vapor that sits just above the altitude at which noctilucent clouds occur. Astronomers recently have been using the sodium layer to create laser-illuminated artificial guide stars for adaptive optics telescopes that remove the distorting affects of atmospheric turbulence to produce clearer celestial images. Measurements of the density of sodium and iron atomic vapor layers show that the metal vapor is depleted by over 80 percent when noctilucent clouds are present. "Noctilucent clouds have been shown to act very much like a flycatcher for sodium and iron atoms," Bellan says. Indeed, in laboratory experiments, other researchers have found that at the frigid temperatures (-123 degrees Celsius) within noctilucent clouds, atoms in sodium vapor quickly become deposited on the surface of ice to form a metallic film. More Coyote Gulch coverage here. "cc" 6:33:43 AM

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