ผลการค้นหา

Carbonation

แปลว่า(Concrete Engineering) 1) Reaction between the products of portland cement (soluble calcium hydroxides), water and carbon dioxide to produce insoluble calcium carbonate (efflorescence). 2) Soft white, chalky surface dusting of freshly placed, unhardened concrete caused by carbon dioxide from unvented heaters or gasoline powered equipment in an enclosed space. 3) Carbonated, dense, impermeable to absorption, top layer of the surface of concrete caused by surface reaction to carbon dioxide. This carbonated layer becomes denser and deeper over a period of time. 4) Reaction with carbon dioxide which produces a slight shrinkage in concrete. Improves chemical stability. Concrete masonry units during manufacturing may be deliberately exposed to carbon dioxide after reaching 80% strength to induce carbonation shrinkage to make the units more dimensionally stable. Future drying shrinkage is reduced by as much as 30%.

A Sheet Metal Screw

แปลว่า(english) Sheet metal screws with (a) sharp-pointed ends; and (b) fewer threads per inch than type AB screws; and (c) deeper threads with bettere gripping power than type AB. The industrial Fasteners Institue incorrectly labes type A an “obsolete” thread though it is universally preferred in 18-8 stainless over type AB, especially by the marine industry.