Word: coolants
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Dates: during 1980-1989
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...millenniums, the process of ozone production and destruction has been more or less in equilibrium. Then in 1928 a group of chemists at General Motors invented a nontoxic, inert gas (meaning that it does not easily react with other substances) that was first used as a coolant in refrigerators. By the 1960s, manufacturers were using similar compounds, generically called chlorofluorocarbons, as propellants in aerosol sprays. As industrial chemicals, they were ideal. "The propellants had to be inert," says Chemist Ralph Cicerone, of the National Center for Atmospheric Research. "You didn't want the spray in a can labeled 'blue paint...
...have stumbled on an unusual class of ceramic compounds that change everything. They too must be cooled to become superconductors, but only to a temperature of 98 K (-283 degrees F). And that suddenly brings superconductivity into the range of the practical; liquid helium can be replaced as a coolant by liquid nitrogen, which makes the transition from a gas at the easily produced temperature of 77 K (-320 degrees F). Moreover, liquid nitrogen is cheaper by the quart than milk and so long- lasting that scientists carry it around in ordinary thermos bottles. Also, the & ceramics may be able...
...their previous attitudes, they emit radiation that produces detailed images of the body's soft tissues. MRI machines in use today are enormous (6 ft. by 8 ft. by 10 ft.), largely because of the more than $100,000 worth of bulky insulation required to preserve the liquid helium coolant, which costs an additional $30,000 annually. The improved economics of the new superconductors, says Walter Robb, of General Electric's Research and Development Center, should eventually enable medical institutions to install many more MRI machines, which are invaluable for diagnosing disorders like brain tumors...
...planning the train, Japanese engineers chose superconducting magnets ( because for a given input of electricity they generate more intense magnetic fields -- and thus greater lifting and propulsion power -- than conventional electromagnets. The drawback: the liquid-helium coolant needed for the superconducting magnets is expensive, and a heavy compressor is required in each coach to reliquefy the evaporating helium. That is why maglev engineers are excited by the idea of the new high-temperature superconductors, which would use considerably less expensive liquid nitrogen as a coolant and require far smaller compressors. The developments of the past few months, says Research Chief...
...Percy's answer threatens, for a time, to stop The Thanatos Syndrome dead in its tracks. Tom, aided by his young, distant and potentially kissing cousin Lucy Lipscomb, herself a doctor and an epidemiologist, discovers that the local water supply is being laced with heavy sodium from the coolant of a nearby nuclear power plant. Whodunit? Not, it turns out, the National Institutes of Health or the Nuclear Regulatory Commission. The villains are a couple of doctors, both known to Tom, who have contrived on their own to salvage the "American social fabric" by doping the local populace...