Any materials scientist will tell you that hydrogen is a tough nut to crack. Although the simplest of the atoms, hydrogen in its molecular state is incredibly complex. The long-sought goal of turning the element into a metal, it has been predicted, would require pressure close to that found at the center of the Earth. Researchers at Cornell University (Ithaca, NY) have dispelled that theory: They submitted hydrogen gas to just such pressure, but the element remained unchanged. "It seems," says Cornell's Arthur Ruoff, "that the pressure required for this transition is even higher than previously thought." The researchers found that solid hydrogen showed no signs of looking like a metal at pressures of up to 342 GPa. The pressure at the center of the Earth is about 361 GPa--more than four million times surface pressure. Such incredible pressure was achieved at Cornell by compressing the hydrogen in a diamond anvil cell, a small device consisting of pairs of the highest quality diamonds with tips beveled to one-fourth the diameter of a human hair. The diamonds, 15 in all, ultimately cracked. E-mail firstname.lastname@example.org.
On Memorial Day, Americans remember the sacrifices the US armed forces have made, and continue to make, in service to the country. All of us should also consider the developments in technological capabilities and equipment over the years that contribute to the success of our military operations.
Advanced visualization can depict an entire plant in motion, while also detailing an individual workstation. Individual products can be rendered different for each discipline involved — marketing, engineering, or suppliers.
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