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## Paris point Quick reference

### A Dictionary of Weights, Measures, and Units

...point 20 / 3 mm, previously used for footware; see also French scale...

## vigesimal Quick reference

### A Dictionary of Weights, Measures, and Units

...[a composite adjective from Greek and Latin for 20] With divisor/multiplier steps of 20, in contrast with the steps of 2 for binary , of 10 for decimal , of 60 for sexagesimal ,...

## mebi- Quick reference

### A Dictionary of Weights, Measures, and Units

...[mega- binary] informatics . Symbol Mi. The 1 048 576 = 2 20 multiplier, as mebibytes (MiB) and mebibits (Mib). See kibi-...

## Sumner unit Quick reference

### A Dictionary of Weights, Measures, and Units

...unit [ J. B. Sumner ; USA 1877–1955 ] chemistry . For enzymes, the amount that liberates 1 mg of ammoniacal nitrogen in five minutes at 20° C, = 14.28 enzyme...

## twenty-twenty Quick reference

### A Dictionary of Weights, Measures, and Units

...human vision, the ability to identify an alphanumeric character ⅓ in (8 mm) high at a distance of 20 ft (6.1∼ m). Applied separately to each eye, the latter figure is increased for sub-normal vision proportionally to the increase in size necessary for identification; thus 20 / 30 indicates an eye that can identify at 20 ft what a normal eye can identify at 30 ft, equivalently how much the standard characters would have to be enlarged to be read at 20 ft, i.e. by 3⁄2 to ½ in (12 mm) in the given example. There is a corresponding scale for ordinary print...

## body mass index Quick reference

### A Dictionary of Weights, Measures, and Units

...mass index health . The ratio of a person's mass in kilograms to the square of their height in metres. Providing a rough correction for mass relative to height, it is approximately 20 for a ‘trim’ person, 25 for overweight, 30 for...

## SAE Quick reference

### A Dictionary of Weights, Measures, and Units

.... A scheme for grading lubricating oils according to their viscosity under varying temperature conditions. Approximate equivalents in centipoises are in Table 45. Table 45 at: 0°F (-17.8°C) 100°F (-37.8°C) 210°F (-98.9°C) SAE 10W 1 950 41 6.0 SAE 20W 6 550 71 8.5 SAE 30 114 11.3 SAE 40 173 14.8 SAE 10W-30 76 12.7 SAE 20W-40 93...

## kiloton Quick reference

### A Dictionary of Weights, Measures, and Units

...of nuclear bombs, the energy of one thousand (short, long, or metric) tons of the explosive trinitrotoluene (TNT) ≈ 4.2∼ GJ (coincidentally ≈ 1 Gcal). The atomic bombs dropped in 1945 on Japan had the energy of about 20 kilotons. Modern ‘tactical’ atomic weapons, relying primarily on fission, have a power in the range 0.1 to 20 kilotons from less than a kilogram of plutonium; ‘strategic’ weapons may be of several hundred kilotons, using fusion triggered by a small fission bomb. See also megaton...

## RSI Quick reference

### A Dictionary of Weights, Measures, and Units

..., RSI value engineering . The SI-expressed unit of thermal insulation corresponding to the earlier R value, i.e. expressed in terms of K⋅m 2 ⋅W -1 instead of °F⋅ft 2 ⋅h⋅Btu -1 , the RSI value = 0.176∼ × R value. Hence R12 becomes RSI 2.1, R20 becomes RSI...

## UHF Quick reference

### A Dictionary of Weights, Measures, and Units

...physics . The ‘ Ultra High Frequency ’ waves of the electromagnetic spectrum , being those of about 1GHz frequency, used, inter alia , for UHF television and for satellite transmissions. North America 470 to 512 MHz for TV channels 14 to 20, 512 to 806 MHz for TV channels 21 to...

## mega- Quick reference

### A Dictionary of Weights, Measures, and Units

...[Gk: ‘great’] Symbol M-. Metric The 10 6 multiplier, e.g. 1 megajoule = 1 MJ = 10 6 J; contractable to meg- before a vowel, e.g. 1 megohm = 1 MΩ = 10 6 Ω. informatics . Sometimes 1 048 576 = 2 20 , but see mebi- then kibi-...

## noise rating number Quick reference

### A Dictionary of Weights, Measures, and Units

...rating number acoustics . Particularly for measuring aircraft and similar noise, the product of noise level in decibels and a factor dependent on frequency (factor = 1 at 1 kHz), the level being measured relative to a minimally perceptive increment of 20 μPa in r.m.s . pressure. Harris C. M. Handbook of Noise Control (New York: McGraw-Hill,...

## noy Quick reference

### A Dictionary of Weights, Measures, and Units

...[annoyance] acoustics USA 1 noy = the loudness of a random noise in the band 910 to 1 090 Hz at 40 db above the standard listener's threshold of 20 μPa. ( Compare sone .) Higher values correspond to the increase in physical intensity in the same proportion increase in loudness relative to intensity. Kryter K. D. J. Acoust. Soc. Amer. 31, 1415–29...

## basis point Quick reference

### A Dictionary of Weights, Measures, and Units

...particular figure is routinely expressed, regardless of the position of the decimal point. Thus, if interest rates are normally expressed (as a percentage) to two decimal places, then a rise from 5.41 to 5.61 would be termed a rise of 20 basis points (and had it risen by 19, one should say to 5.60 rather than 5.6). That rise of 20 basis points could also be described as a rise of 0.2 percentage points , this latter expression being independent of the number of decimal places cited. (A rise of 0.2 from 5.41 is a rise of 0.2 × 100%/5.41 = 3.7% of the interest...

## preferred numbers Quick reference

### A Dictionary of Weights, Measures, and Units

...2.43 3.07 3.87 4.87 6.15 7.75 9.75 Table 41 R5 R10 R20 R40 true R40′ R20′ R10′ R5″ R10″ R20″ 0 1.0 1.0 1.0 1.0 1.000 0 1.0 1.0 1.0 1.0 1.0 1.0 1 1.06 1.059 3 ∼ 1.05 2 1.12 1.12 1.122 0 ∼ 1.1 1.1 1.1 3 1.18 1.188 5 ∼ 1.2 4 1.25 1.25 1.25 1.258 9 ∼ 1.25 1.25 1.25 1.2 1.2 5 1.32 1.333 5 ∼ 1.3 6 1.4 1.4 1.412 5 ∼ 1.4 1.4 1.4 7 1.5 1.496 2 ∼ 1.5 8 1.6 1.6 1.6 1.6 1.584 9 ∼ 1.6 1.6 1.6 1.5 1.5 1.6 9 1.7 1.678 8 ∼ 1.7 10 1.8 1.8 1.778 3 ∼ 1.8 1.8 1.8 11 1.9 1.883 6 ∼ 1.9 12 2.0 2.0 2.0 1.995 3 ∼ 2.0 2.0 2.0 2.0 2.0 13 2.12 2.113 5 ∼ 2.1 14 2.24 2.24 2.238 7 ∼ 2.2 2.2...

## fluid ounce Quick reference

### A Dictionary of Weights, Measures, and Units

...ounce volume . Symbol fl oz, also liq oz. Volume of 1 oz avoirdupois of water. BI 1 / 20 BI pt = 1 / 160 BI gallon = 28.413∼ mL – see Table 16(a). US-C (Symbol also liquid ounce, liq oz) Solely for liquids, 1 / 16 US pt = 1 / 128 US gallon = 29.574∼ mL; see Table 16(b). Table 16(a) BI SI US-C liq minim … … … 59.2∼ μL 0.0200∼ oz 60 fluid dram … … 3.55∼ mL 0.120∼ oz 480 8 fl oz … 28.4∼ mL 0.961∼ oz 20 pint 568.∼ mL 19.2∼ oz See gallon for upward extension. Table 16(b) US-C liq SI minim … … … 61.6∼ μL 60 fluid dram … … 3.70∼ mL 480 8 fl oz, liq...

## phon Quick reference

### A Dictionary of Weights, Measures, and Units

...acoustics . Symbol P. A measure of loudness level, as agreed in 1937 at the first International Acoustical Conference, Nature 140, 370 (1937) the decibels of sound pressure above 20 μPa of a pure tone of 1 000 Hz subjectively judged by a group of listeners as equally loud as the sound being measured. ISO 131:1979 Acoustics – Expression of Physical and Subjective Magnitudes of Sound and Noise in Air (The reference pressure was 316 μPa earlier.) If p and s represent the loudness respectively in phons and sones, then p = 40 + 10 log 2 s...

## poise Quick reference

### A Dictionary of Weights, Measures, and Units

.... Symbol P. Metric-c.g.s. Identically dyne⋅second per square centimetre (dyn⋅s⋅cm -2 ) = 10 -1 N⋅s⋅m -2 = 10 -1 Pa⋅s(= cm -1 ⋅g⋅s -1 in c.g.s. base terms). Hence • P⋅(g⋅cm -3 ) -1 = stokes for kinematic viscosity. The poise is a large unit for most purposes, water at 20°C having a viscosity of 10.020∼ mP and most free-flowing liquids typically being similar; gases are around 1 μP. There is no equivalent special term in the...

## sexagesimal Quick reference

### A Dictionary of Weights, Measures, and Units

...[Lat: ‘sixtieth’] With divisor/multiplier steps of 60, in contrast with the steps of 10 for decimal , of 12 for duodecimal , of 20 for vigesimal , etc. The sexagesimal approach was dominant in Ancient Mesopotamia, and survives today on the clock and in the degrees for measurement of plane angles. Babylonian numerals had a composite two-part structure, the first counting 0 to 4 dozens, the second part 0 to 11 units, the composite 4, 11 meaning 59, i.e. 1 short of...

## sone Quick reference

### A Dictionary of Weights, Measures, and Units

...acoustics . 1 sone = the loudness of a simple tone of 1 kHz at 40 db above the standard listener's threshold of 20 μPa (≈ the hum of a modern refrigerator). ISO 131:1979 Acoustics – Expression of Physical and Subjective Magnitudes of Sound and Noise in Air A sound twice as loud has value 2, etc. Kryter K. D. J. Acoust. Soc. Amer. 31, 1415–29 (1959) If s and p represent the loudness respectively in sones and phons, then s = 2 ( p -40)/10...