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Ships to get non-toxic, anti-barnacle coating

The fouling of ships’ hulls, whether by barnacles and seaweed or by slime-creating bacteria, is a major problem for shipping worldwide, and particularly for navies. It has been estimated, for example, that fouling of hulls can create such turbulence as a ship moves through the water that fuel consumption is increased by as much as 30 percent. Traditionally major users of ships, like the U.S. Navy, have attempted to resist fouling by painting hulls with paints containing copper or triorganotin, a tin-based compound. But these paints are highly toxic and can leach into the water, killing marine life. That’s why their use increasingly is being prohibited. But help is at hand: A research group at Cornell University, Ithaca, N.Y., led by Christopher Ober, has developed two types of non-toxic paint, one hydrophilic and one hydrophobic, that effectively prevent fouling, whether by bacteria or barnacles. The paints act not only by minimizing adhesion by organisms but also by enabling hulls to become self-cleaning: As a ship moves through the water at 10 to 15 knots, the turbulence created removes the clinging barnacle or seaweed.

Biodegradable plastic imitates bacteria

Finding an economical way to make a polyester commonly found in many types of bacteria into a plastic with uses ranging from packaging to biomedical devices is a long-held scientific goal. Such a polymer would be a “green” plastic, in that it would be biodegradable. Geoffrey Coates, a professor of chemistry and chemical biology at Cornell University, Ithaca, N.Y., has partially achieved this goal by discovering a highly efficient chemical route for the synthesis of the polymer, known as poly(beta-hydroxybutyrate) or PHB. The thermoplastic polyester is widely found in nature, particularly in some bacteria, where it is formed as intracellular deposits and used as a storage form of carbon and energy. And yet it shares many of the physical and mechanical properties of petroleum-based polypropylene, with the added benefit of being biodegradable.

Artificial worlds used to unlock secrets of real human interaction

What do flocks of birds, traffic jams, fads, drinking games, forest fires and residential segregation have in common? The answer could come from a new computational research method called agent-based modeling. Michael Macy, a sociologist at Cornell University, Ithaca, N.Y., is using this powerful new tool to look for elementary principles of self-organization that might shed new light on long-standing puzzles about how humans interact. A professor and chair of Cornell’s Department of Sociology, Macy will speak Feb. 14 at the annual meeting of the American Association for the Advancement of Science in Denver in a symposium, “Artificial Agent Societies: A Computational Future for the Social Sciences.”