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For more information on these science news and feature story tips, please contact the public information officer at the end of each item at (703) 292-8070. Editor: Tom Garritano Contents of this News Tip:
Nano-Structured Diamond Coating Will Reduce Wear in Mechanical DevicesYour future disk drive or artificial hip could be coated with a nano-sized film of synthetic diamond. National Science Foundation (NSF)-supported scientists at the University of Alabama at Birmingham have developed a patented process to deposit diamond particles on metal that has the potential to significantly reduce surface friction and wear. Diamond, one of the hardest substances, is already used to coat drill bits and other surfaces that require extreme durability. But those surfaces are rough at the molecular level, which is measured in nanometers-each of which is one billionth of a meter. Physics professor Yogesh Vohra and graduate student Shane Catledge used a nano-scale chemical vapor deposition process to bond a diamond film to metal surfaces, creating an ultra-smooth coating that is also more resistant to wear. These nano-structured diamond films have a hardness value of about 80 percent of that of a perfect crystalline diamond and have an exceptional adhesion to the underlying metal. The diamond surfaces are potentially useful in electronic components, magnetic storage technology and biomedical implants. [Amber Jones] El Niño Predicted with the Help of a Wind TriggerJust as a spark can grow into a fire, so may small departures of winds from the normal seasonal cycle in the far western equatorial Pacific trigger a full-blown El Niņo. Writing in the February 15th issue of the journal Geophysical Research Letters, scientists Allan Clarke and Stephen Van Gorder of Florida State University-who are funded by NSF's division of atmospheric sciences-describe the model they have developed to predict El Niņo using this trigger. The departure of the wind from its normal seasonal cycle is called a wind "anomaly." The ocean is hypersensitive to zonal (east-west) equatorial wind anomalies. Analysis of data from eight El Niņos since 1960 shows that they tend to begin as small westerly wind anomalies in the far western equatorial Pacific. They grow and move eastward to the central equatorial Pacific as the ocean and atmosphere interact to reinforce the anomaly. La Niņas are similarly associated with easterly wind anomalies. By observing that the far western equatorial Pacific's wind anomaly typically precedes El Niņo or La Niņa by about six months, Clarke and Van Gorder developed a model that, in spite of its simplicity, performs as well as or better than the leading El Niņo prediction models. The model, which weighs other factors such as the east-west movement of a huge pool of warm water in the Pacific, also predicts the demise of El Niņo and La Niņa. [Cheryl Dybas] Silence of the Clams: Upstream Dams Imperil Downstream ClamsA species of clam living in Mexico's Colorado River Delta is being driven to extinction, because humans use so much river water there that only a trickle now reaches the sea. In a paper published in the February 2001 issue of the journal Conservation Biology, NSF-funded paleobiologist Karl Flessa of the University of Arizona at Tucson says that Mulinia coloradoensis, the Colorado clam, was once so abundant that entire islands in the river are built of its empty shells. Fewer than 30 of these clams exist today in the wild, however, due to changes in its environment. The Colorado River once delivered all of its fresh water to a delta in the northern Gulf of California. The river now dries up before reaching the delta due to nearly complete diversion of river water for irrigation and domestic uses in the U.S. and Mexico. "Turning off the water supply of the Colorado River also turns off the supply of nutrients that reach the northern Gulf of California," says Flessa. And that has probably had a big effect, Flessa believes, not just on clams, but on shrimp and fish in the area. "The change in the environment-the lack of freshwater-has
caused the demise of these clams," says Flessa. By
comparing the chemistry of shells from live clams
with shells from long-dead clams, Flessa and his colleagues
documented a change in salinity of the delta's river
water since the 1930s. Shells of clams that lived
before 1930 contained more of the freshwater form
of oxygen than shells from clams living in the delta
today. For the Colorado clam to survive, Flessa believes,
more river water must be allowed to reach the Gulf
of California. He adds that his research team's estimates
of the delta's past salinity can serve as a valuable
guideline for restoration efforts. Flessa's work is
funded by NSF's division of earth sciences. [Cheryl
Dybas]
NSF is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $4.5 billion. NSF funds reach all 50 states, through grants to about 1,600 universities and institutions nationwide. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards.
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