Bjorn Buckwalter, firstname.lastname@example.org
= Summary =
This module defines units that are not part of the SI, with the
exception of those defined in the 'SIUnits' module (units outside
of the SI accepted for use with the SI).
Any chapters, sections or tables referenced are from  unless
> module Numeric.Units.Dimensional.NonSI where
> import Numeric.Units.Dimensional.Prelude
> import qualified Prelude
= Neper, bel, shannon and the like =
The units of section 5.1.2 are purposefully (but not permanently)
omitted. In fact the logarithmic units (see section 8.7) are
problematic and it is not clear how to implement them. Perhaps with
a conversion function similar to for degrees Celsius.
= Table 7 =
"Units accepted for use with the SI whose values in SI units are
When  was published The electronvolt had a standard combined
uncertainity of 0.00000049e-19 J and the unified atomic mass unit
had a combined uncertainty of 0.0000010e-27 kg.
> electronVolt :: Fractional a => Unit DEnergy a
> electronVolt = prefix 1.60217733e-19 joule
> unifiedAtomicMassUnit :: Fractional a => Unit DMass a
> unifiedAtomicMassUnit = prefix 1.6605402e-27 (kilo gram)
= Standard gravity =
In order to relate e.g. pounds mass to pounds force we define the unit
'gee' equal to the standard gravity g_0: the nominal acceleration of a
body in free fall in a vacuum near the surface of the earth (note that
local values of acceleration due to gravity will differ from the standard
gravity). I.e. g_0 = 1 gee.
> gee :: Fractional a => Unit DAcceleration a
> gee = prefix 9.80665 meter / second ^ pos2
= Inch-pound units =
Some US customary (that is, inch-pound) units.
> inch, foot :: Fractional a => Unit DLength a
> inch = prefix 2.54 (centi meter)
> foot = prefix 12 inch
> poundMass, ounce :: Fractional a => Unit DMass a
> poundMass = prefix 0.45359237 (kilo gram)
> ounce = prefix 28.349523 gram
> poundForce :: Fractional a => Unit DForce a
> poundForce = poundMass * gee
Pounds of force per square inch.
> psi :: Fractional a => Unit DPressure a
> psi = poundForce / inch ^ pos2
= Various other (non inch-pound) units =
> yard, mile, nauticalMile :: (Fractional a) => Unit DLength a
> yard = prefix 3 foot
> mile = prefix 1760 yard
> nauticalMile = prefix 1852 meter
> revolution :: (Floating a) => Unit DOne a
> revolution = prefix (2 Prelude.* Prelude.pi) radian
> solid :: (Floating a) => Unit DOne a
> solid = prefix (4 Prelude.* Prelude.pi) steradian
> teaspoon :: (Fractional a) => Unit DVolume a
> teaspoon = prefix 5 (milli liter)
The IAU recommends that:
Although there are several different kinds of year (as there are
several kinds of day), it is best to regard a year as a julian
year of 365.25 days (31.5576 Ms) unless otherwise specified.
This aligns well with my needs so I'm happy to oblige. We define
the year in terms of seconds in order to avoid a 'Fractional'
constraint, and also provide a Julian century.
> year, century :: Num a => Unit DTime a
> year = prefix 31557600 second
> century = prefix 100 year
= Pressure units =
Psi was defined earlier.
> bar :: (Fractional a) => Unit DPressure a
> bar = prefix 1.0e5 pascal
The standard atmosphere (atm) is an established constant. It is
approximately equal to typical air pressure at earth mean sea
> atmosphere :: (Fractional a) => Unit DPressure a
> atmosphere = prefix 101325 pascal
A technical atmosphere (symbol: at) is a non-SI unit of pressure equal
to one kilogram-force per square centimeter.
> technicalAtmosphere :: (Fractional a) => Unit DPressure a
> technicalAtmosphere = kilo gram * gee * centi meter ^ neg2
Manometric pressure units:
Per Wikipedia one mmHg (millimeter of mercury) is defined as:
The pressure exerted at the base of a column of fluid exactly 1 mm high,
when the density of the fluid is exactly 13.5951 g/cm^3, at a place
where the acceleration of gravity is exactly 9.80665 m/s^2.
The chosen fluid density approximately corresponds to that of mercury
at 0 deg. Under most conditions, 1 mmHg is approximately equal to 1 torr.
> mmHg :: (Fractional a) => Unit DPressure a
> mmHg = prefix 13.5951 gram * centi meter ^ neg3 * milli meter * gee
One torr (symbol: Torr) is defined as 1/760 atm, which is approximately equal
to 1 mmHg.
> torr :: (Fractional a) => Unit DPressure a
> torr = prefix (1 Prelude./ 760) atmosphere
= Radiation =
> rad :: (Fractional a) => Unit DAbsorbedDose a
> rad = centi gray
= Kinematic Viscosity =
> stokes :: (Fractional a) => Unit DKinematicViscosity a
> stokes = centi meter ^ pos2 / second
= References =