Technology Notes

Among recent gifts of science to war, industry, other human pursuits:

Nylon bearings. Advantages, claimed in a Du Pont patent: no lubrication required; less friction, vibration, heat; longer wear and ability to carry heavier loads than bearings made of bronze, brass, babbitt metal. In the past, bearings have been made of synthetic resins, but they had to be reinforced with fabric fillers, required water lubrication.

Explosive rivets, developed by Du Pont after the basic invention in 1937 by two employes of famed German Plane Builder Ernst Heinkel. A high explosive nests in a cavity at the headless end of an aluminum-alloy rivet. When heat is applied to the head by an electric riveting gun, the charge explodes at the other end, forms a "blind" head, sets the rivet. Explosive charges can be controlled to adjust the size and shape of the head to within .02 in. This breaks a major plane-building bottleneck: riveting points which can be reached from only one side. So troublesome have been these inaccessible points that plane designs have often been modified to avoid them, but there are still 800 in an all-metal pursuit ship, 10,000 in a large bomber. A skilled workman, with costly tools, has been able to set two to four old-fashioned rivets per minute. But, with fairly simple tools, almost anyone can set 15 to 20 explosive rivets.

Electrically heated flying suits, so perfected that the U.S. Army Air Corps has ordered 12,000 of them from General Electric. In developing the suits, a Flying Fortress crew last winter flew 10,000 feet up over Alaska in --30DEG weather, dressed only in long woolen underwear through which electrical coils were woven. The new suits are lighter and cheaper than the sheepskin garments now used, and they leave a flier nimbler at his controls and guns. Heat can be adjusted for outside temperatures from 70DEG to --60DEG, can be increased to protect injured fliers from shock and pneumonia. General Electric analyzed the electrically heated uniform of a German flier shot down over England, found it so inefficient as to be nigh worthless.

A chlorinator which prevents public water supplies from being needlessly chlorine-smelly. After initial chlorine treatment has killed organic matter in the water, a sensitive cell measures the residual chlorine by the amount of electric current which will pass through the water. Further chlorine is then automatically added only as needed to protect the water on its way to the ultimate faucet, instead of according to the volume of water, as at present. Now used at New Haven, Conn., the new chlorinators will soon be installed in New York and other U.S. cities.

Tires 100% liquid-filled, to weigh down the structurally light rear end of tractors, provide better traction. The 15% solution of calcium chloride in water will not freeze above --20DEG, reduces bouncing and sidewall buckling, requires little care because water will not diffuse through an inner tube as air does. The liquid distributes pressure to all parts of the tire, unlike a solid filler. The tire was developed by Goodyear, is not yet on the market.

A solar-energy heater patented last week by Dr. Charles G. Abbot, secretary of the Smithsonian Institution and a tire less inventor of solar-energy machines. His newest eliminates many of the circulation pipes which made older models clumsy, costly, tricky. A concave cylindrical mirror, clockworked to follow the sun, focuses the solar rays on a vacuum-insulated tube filled with a heat-absorbing liquid such as black petroleum. As the petroleum heats, it rises to a reservoir, from which cool petroleum then descends into the heating element by gravity. As the reservoir gets hotter, it can be used for cooking, generating steam and even refrigerating (by the absorption method). In a large ma chine, heat gathered during sunny days will last usefully through several cloudy days.

Beef powder. Broadcast BBC last week: "Mr. J. B. Cramsie, former chairman of Australia's Meat Council, declared that this meat powder might solve Britain's meat storage and transport problem . . . as it needs no refrigeration and takes only a fraction of the cargo space needed for untreated meat."

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