## Modelica.Constants

Mathematical constants and constants of nature

### Information

This package provides often needed constants from mathematics, machine dependent constants and constants from nature. The latter constants (name, value, description) are from the following source:

Peter J. Mohr and Barry N. Taylor (1999):
  CODATA Recommended Values of the Fundamental Physical Constants: 1998. Journal of Physical and Chemical Reference Data, Vol. 28, No. 6, 1999 and Reviews of Modern Physics, Vol. 72, No. 2, 2000. See also http://physics.nist.gov/cuu/Constants/

Main Author:
  Martin Otter
  Deutsches Zentrum fuer Luft und Raumfahrt e.V. (DLR)
  Oberpfaffenhofen
  Postfach 1116
  D-82230 Wessling
  email: Martin.Otter@dlr.de

Release Notes:

- Dec. 9, 1999 by Martin Otter:
  Constants updated according to 1998 CODATA values. Using names, values and description text from this source. Included magnetic and electric constant.
- Sept. 18, 1999 by Martin Otter:
  Constants EPS, INF, SMALL introduced.
- Nov 15, 1997 by Martin Otter:
  Realized.

Copyright © 1999-2002, Modelica Association and DLR.

The Modelica package is free software; it can be redistributed and/or modified under the terms of the Modelica license, see the license conditions and the accompanying disclaimer in the documentation of package Modelica in file "Modelica/package.mo".

### Types and constants

constant Real e=Modelica.Math.exp(1.0);

constant Real pi=2*Modelica.Math.asin(1.0);

constant Real D2R=pi/180 "Degree to Radian";

constant Real R2D=180/pi "Radian to Degree";

constant Real eps=1.e-15 "Biggest number such that 1.0 + eps = 1.0";

constant Real small=1.e-60 "Smallest number such that small and -small are representable on the machine";

constant Real inf=1.e+60 "Biggest Real number such that inf and -inf are representable on the machine";

constant Integer Integer_inf=2147483647 "Biggest Integer number such that Integer_inf and -Integer_inf are representable on the machine";

constant SI.Velocity c=299792458 "Speed of light in vacuum";

constant SI.Acceleration g_n=9.80665 "Standard acceleration of gravity on earth";

constant Real G(final unit="m3/(kg.s2)") = 6.673e-11 "Newtonian constant of gravitation";

constant Real h(final unit="J.s") = 6.62606876e-34 "Planck constant";

constant Real k(final unit="J/K") = 1.3806503e-23 "Boltzmann constant";

constant Real R(final unit="J/(mol.K)") = 8.314472 "Molar gas constant";

constant Real sigma(final unit="W/(m2.K4)") = 5.670400e-8 "Stefan-Boltzmann constant";

constant Real N_A(final unit="1/mol") = 6.02214199e23 "Avogadro constant";

constant Real mue_0(final unit="N/A2") = 4*pi*1.e-7 "Magnetic constant";

constant Real epsilon_0(final unit="F/m") = 1/(mue_0*c*c) "Electric constant";

constant NonSI.Temperature_degC T_zero=-273.15 "Absolute zero temperature";

constant Real E=e;

constant Real PI=pi;

constant Real EPS=eps;

constant Real SMALL=small;

constant Real INF=inf;

constant Real INTEGER_INF=Integer_inf;

constant Real C=c;

constant Real H=h;

constant Real K=k;

constant Real R0=R;

constant Real SIGMA=sigma;

constant Real G_EARTH=g_n;

constant Real T_ZERO=T_zero;