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A minute of arc is π 10 800 of a radian . A second of arc, arcsecond (arcsec), or arc second, denoted by the symbol ″, [2] is 1 60 of an arcminute, 1 3600 of a degree, [1] 1 1 296 000 of a turn, and π 648 000 (about 1 206 264.8) of a radian. These units originated in Babylonian astronomy as sexagesimal (base 60) subdivisions of the degree ...
In fractions like "2 nanometers per meter" (2 n m / m = 2 nano = 2×10 −9 = 2 ppb = 2 × 0.000 000 001), so the quotients are pure-number coefficients with positive values less than or equal to 1. When parts-per notations, including the percent symbol (%), are used in regular prose (as opposed to mathematical expressions), they are still pure ...
1 thou is equal to: 0.001 international inches (1 international inch is equal to 1,000 thou) 0.0254 mm, or 25.4 μm (1 millimetre is about 39.37 thou) History of usage. The introduction of the thousandth of an inch as a base unit in engineering and machining is generally attributed to Joseph Whitworth who wrote in 1857:
The millimeter of mercury by definition is 133.322387415 Pa (13.5951 g/cm 3 × 9.80665 m/s 2 × 1 mm), which is approximated with known accuracies of density of mercury and standard gravity. The torr is defined as 1 / 760 of one standard atmosphere, while the atmosphere is defined as 101325 pascals. Therefore, 1 Torr is equal to 101325 / 760 Pa.
A typical protein in bacteria, such as E. coli, may have about 60 copies, and the volume of a bacterium is about 10 −15 L. Thus, the number concentration C is C = 60 / (10 −15 L) = 6 × 10 16 L −1. The molar concentration is c = C / N A = 6 × 10 16 L −1 / 6 × 10 23 mol −1 = 10 −7 mol/L = 100 nmol/L. Reference ranges for blood ...
In chemistry, molality is a measure of the amount of solute in a solution relative to a given mass of solvent. This contrasts with the definition of molarity which is based on a given volume of solution. A commonly used unit for molality is the moles per kilogram (mol/kg). A solution of concentration 1 mol/kg is also sometimes denoted as 1 ...
Schematic of a machine tap. Below is a comprehensive drill and tap size chart for all drills and taps, imperial and metric, up to 36.5 millimetres (1.44 in) in diameter.. In manufactured parts, holes with female screw threads are often needed; they accept male screws to facilitate the building and fastening of a finished assembly.
Monitoring the sky at 3, 10, 30, 100 and 300 microns, especially at 1, 3, and 10 mm, in order to identify one hundred of the most powerful sources among those observed and at each frequency; Study in detail the properties of quasars and other unusual objects;