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CR-39 plastic has an index of refraction of 1.498 and an Abbe number of 58. CR-39 is now a trade-marked product of PPG Industries. [2] An alternative use includes a purified version that is used to measure ionising radiation such as alpha particles and neutrons. Although CR-39 is a type of polycarbonate, it should not be confused with the ...
CR-39 is commonly used in the manufacturing of plastic eyeglass lenses. Ammonia was in short supply after the end of World War II; Columbia-Southern was expected to begin producing the chemical in late 1954. [ 7 ]
Backface deformation is defined in NIJ Standard-0101.07 as "the indentation in the backing material caused by a projectile impact on the test item during testing". [10] It is measured by shooting armor mounted in front of a backing material, typically oil-based modeling clay. The clay is used at a controlled temperature and verified for impact ...
Scratch-resistant coatings are added to glasses due to scratches' extreme ability to impact a wearer's vision. Even when optical glasses are made of high scratch-resistances glass, polycarbonate, or CR-39, coatings are still used. Optical coatings include diamond-like carbon (DLC) and anti-reflective-scratch hybrid coatings. Diamond-like Carbon ...
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Lenses sold in the US must pass the Food and Drug Administration ball-drop impact test, and depending on needed index these seem to currently have "best in class" Abbe vs Index ( N d): Glass (2× weight of plastics) or CR-39 (2 mm vs. 1.5 mm thickness typical on newer materials) 58 @ 1.5, Sola Spectralite (47 @ 1.53), Sola Finalite (43 @ 1.6 ...
Duplex stainless is widely used in the industry because it possesses excellent oxidation resistance but can have limited toughness due to its large ferritic grain size, and they have hardened, and embrittlement tendencies at temperatures ranging from 280 to 500 °C, especially at 475 °C, where spinodal decomposition of the supersaturated solid ...
CPM S110V [39] has higher corrosion resistance than S90V and marginally better wear resistance. The additional corrosion resistance while retaining all the benefits of S90V makes this steel extremely desired for kitchen cutlery. [40] CPM S125V. It contains 3.25% carbon, 14% chromium and 12% vanadium, as well as other elements in alloy.