Word: ultraviolet
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...seal the tooth. Then a paste composed of plastic and finely ground quartz, glass or silica is patted on in thin layers tinted to match the natural teeth and molded into the desired shape. After each layer is applied, it is exposed for up to 40 seconds to either ultraviolet or visible light beams. This triggers a reaction that hardens and bonds the layer to the underlying material. The newly built tooth is then contoured and polished...
John Kohl, an associate of the Harvard College Observatory, has designed an ultraviolet coronograph for the space shuttle that will take advantage of Columbia's position above the earth's atmosphere. A coronograph is a telescope engineered specifically for observing the corona, the outer atmosphere of the sun, by blocking the light of the sun's disk. The corona, an area of extremely low density and high temperature, can be most clearly observed naturally during a solar eclipse. Kohl's coronograph would pick up the ultraviolet light emitted by the corona and analyse it to reveal the density and velocity...
...mechanical sculpture garden of chrome, leather and cable: stationary bicycles, cross-country skiing simulators, rowing machines, Nautilus weight stations and racks of dumbbells positioned around the spacious, brown-carpeted gym. Down a hallway hung with modern paintings are whirlpool baths and a sunning room studded with ultraviolet and infra-red lamps. Near by: offices for a physician and a full-time exercise physiologist...
When the Government cracked down on the use of chemicals called chlorofluorocarbons in aerosol sprays three years ago, a major row erupted. Some scientists welcomed the ban, contending that the synthetic compounds-like Freon -were destroying the earth's ozone layer, a shield against the sun's ultraviolet rays. They warned that loss of ozone could cause more cancer and perhaps alter the weather. Other scientists pooh-poohed such doomsday scenarios as unproved...
Herbert Wiser, an EPA science adviser, called the findings no more than "mildly suggestive." One problem, added Shelby Tilford, NASA'S chief of atmospheric processes, is that the amount of ozone may fluctuate with variations in the sun's ultraviolet radiation. To help settle the argument, Harvard's James G. Anderson plans to launch a huge balloon, 450 ft. in girth, in New Mexico next fall. Equipped with a battery of sensitive devices, its gondola will move up and down like a yo-yo through the upper atmosphere, between altitudes of 12 miles and 25 miles...