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The refractive index of sphalerite (as measured via sodium light, average wavelength 589.3 nm) ranges from 2.37 when it is pure ZnS to 2.50 when there is 40% iron content. [6] Sphalerite is isotropic under cross-polarized light, however sphalerite can experience birefringence if intergrown with its polymorph wurtzite; the birefringence can ...
In each form, the coordination geometry at Zn and S is tetrahedral. The more stable cubic form is known also as zinc blende or sphalerite. The hexagonal form is known as the mineral wurtzite, although it also can be produced synthetically. [2] The transition from the sphalerite form to the wurtzite form occurs at around 1020 °C.
For example, a popular 3 ⁄ 4-inch 150 psi sprinkler valve, intended for 24 VAC (50–60 Hz) residential systems, has a momentary inrush of 7.2 VA, and a holding power requirement of 4.6 VA. [5] Comparatively, an industrial 1 ⁄ 2-inch 10,000 psi valve, intended for 12, 24, or 120 VAC systems in high-pressure fluid and cryogenic applications ...
The ball valve's ease of operation, repair, and versatility lend it to extensive industrial use, supporting pressures up to 1,000 bar (100 MPa; 15,000 psi) and temperatures up to 750 °F (400 °C), depending on design and materials used. Sizes typically range from 0.2 to 48 in (5 to 1200 mm).
A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. [ 1 ] Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave.
In electrochemistry, a valve metal is a metal which passes current in only one direction. Usually, in an electrolytic cell, it can function generally as a cathode, but not generally as an anode because a (highly resistive) oxide of the metal forms under anodic conditions. [1] Valve metals include commonly aluminium, titanium, tantalum, and niobium.
Björk–Shiley valve, as depicted in patent #US003824629. The Björk–Shiley valve is a mechanical artificial heart valve. The valve was co-invented by American engineer Donald Shiley and Swedish heart surgeon Viking Björk. Beginning in 1971, it has been used to replace aortic valves and mitral valves. It was the first successful tilting ...
The 3 ft 6 in (1,067 mm) Cape gauge 2-6-2+2-6-2 locomotives of the SAR entered service between 1921 and 1929. SAR Class GB no. 2166. In 1921, a single experimental Class GB Garratt entered service, followed by six more in 1924, designed and built by BP. They were superheated, with Belpaire fireboxes, plate frames and Walschaerts valve gear.