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.

'Selfish routing' slows the Internet

The Tragedy of the Commons , as explained by Garrett Harding in his classic 1968 book, is that self-interest can deplete a common resource. It seems this also applies to the Internet and other computer networks, which are slowed by those who hurry the most. Fortunately, say computer scientists at Cornell University in Ithaca, N.Y. , there is a limit to how bad the slowdown can get. And after developing tools to measure how much the performance of a particular network suffers, they say, the way to get improved performance on the Internet is the same as the way to maintain air and water quality: altruism helps.