Discussion
LMNO Engineering wrote the unit conversion computer program in the PHP computer language using
double precision so that the
maximum number of significant digits in the unit conversions could be used. We used the
maximum amount of significant figures for each unit. For instance, Munson et al.
(1998) provides a unit conversion of 1 bushel(US)=0.03523907016688 meter3.
We used all of the digits in our program.
The acceleration of gravity, 9.80665 m/s2, is used to convert between mass and
force such as kilograms and Newtons.
Pound(mass) and pound(force) have identical numerical values. We list both units
because many people are used to using one or the other and like to see them listed
separately.
The BTU and calorie units are thermochemical values.
A year is a calendar year (365 days).
The calculation does not check for impossible input such as temperature below absolute zero.
Abbreviations (selected)
bbl=barrel, BTU=British Thermal Unit, cm=centimeter, ft=foot, km=kilometer, kW=kiloWatt,
lb=pound, lb(f)=pound(force), lb(m)=pound(mass), m=meter, Mcf=thousand cubic feet,
mg=milligram, MGD=million gallons per day, mm=millimeter, MPa=Mega Pascal, min=minute,
N=newton, s=sec=second, UK=United Kingdom (used for gallons), US=United States (used for
gallons and some other units), yr=year
References
Bear, J. 1979. Hydraulics of Groundwater. McGraw-Hill Pub Co.
Munson, B.R., D. F. Young, and T. H. Okiishi. 1998. Fundamentals of Fluid Mechanics. John Wiley and Sons, Inc. 3ed. (This is the best reference for fluid mechanics unit conversions. It indicates which unit conversions are exact by definition and which are approximate - there are some units in existence that cannot be exactly converted from one unit to another. For the non-exact conversions, it provides on the order of 10 significant digits for each unit.)
Perry, R. H. and D. W. Green. 1984. Perry's Chemical Engineers' Handbook McGraw-Hill, Inc. 6ed.
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