The taper rate for all NPT threads is 1â16 (3â4 inch per foot) measured by the change of diameter (of the pipe thread) over distance. The angle between the taper and the center axis of the pipe is 1Â° 47'â² 24â³ (1.7899Â°). Commonly-used sizes are 1/â8, 1/â4, 3/â8, 1â/2, 3â/4, 1, 1 1â/4, 1 1â/2, and 2 inch, appearing on pipes and fittings by most U.S. suppliers.
Schematic representation of the photochemical ozone formation and destruction. Ozone is a gas found in the atmosphere consisting of three oxygen atoms: O 3. Ozone is formed in the atmosphere when energetic ultraviolet (UV) radiation dissociates molecules of oxygen, O 2, into separate oxygen atoms. Free oxygen atoms can recombine to form oxygen molecules but if a free oxygen atom collides with an oxygen molecule, it joins up, forming ozone.
Stratospheric ozone is natu-rally formed in chemical reactions involving ultravioletsunlight and oxygen molecules, which make up 21% ofthe atmosphere. In the first step, sunlight breaks apartone oxygen molecule (O 2) to produce two oxygen atoms(2 O) (see Figure Q2-1).n the strat-osphere, the process begins with an oxygen molecule (O 2) being broken apart by ultraviolet radiation fromthe Sun. In the lower atmosphere (troposphere), ozone is formed in a different set of chemical reactionsinvolving hydrocarbons and nitrogen-containing gases. Stratospheric Ozone Production.