Word: vacuum
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Dates: during 1960-1969
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...Scientists measure high vacuum in torrs. One torr (named after Italian Scientist Evangelista Torricelli, 1608-47, inventor of the mercury barometer) is the pressure that will support a column of mercury one millimeter high...
...when they come in contact in the earth's atmosphere. Exposed to air, they have already become covered with oxide films or a thin layer of gas that keeps the metals from actually touching. National Research scientists were interested in what happens when metals touch in the hard vacuum high above the earth's atmosphere. In their space simulation chamber they created an almost perfect vacuum (10 torr-), the same as spacecraft encounter 500 miles above the earth. In that ultra emptiness, surface gases evaporated; oxide films, once cleaned off, did not return...
National Research scientists have made pieces of metal grab each other in a vacuum until sometimes the "cold-weld"' that formed had 95% of the strength of solid metal. Steel grabs strongly, and the scientists suspect that many other metals will do the same...
...lesson already learned is that moving parts of a space vehicle designed to work in a vacuum for long periods should not have simple metal-to-metal bearings...
...rooms, which are necessary for an ever-increasing number of industrial operations, is to keep dust particles from being released. Smoking is forbidden; so are ordinary pencils, which give off graphite particles. People who work in the clean rooms are "packaged" in special boots, hoods and coveralls and are vacuum-cleaned before they enter. The rooms themselves are vacuumed continually. But despite all these precautions, each cubic foot of their air still contains at least 1,000,000 dust particles that are .3 microns (.000012 in.) or larger in diameter. This is a vast improvement over ordinary air, but Whitfield...