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1   package org.djunits.value.vfloat.scalar.base;
2   
3   import org.djunits.unit.DimensionlessUnit;
4   import org.djunits.unit.ElectricalChargeUnit;
5   import org.djunits.value.vdouble.scalar.Dimensionless;
6   import org.djunits.value.vdouble.scalar.ElectricalCharge;
7   import org.djunits.value.vdouble.scalar.Frequency;
8   import org.djunits.value.vdouble.scalar.Mass;
9   import org.djunits.value.vdouble.scalar.SIScalar;
10  import org.djunits.value.vdouble.scalar.Speed;
11  
12  /**
13   * Various physical constants. For many, see
14   * <a href="https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_base_units">Wikipedia 2019 redefinition of the SI base
15   * units</a>
16   * @author <a href="https://www.tudelft.nl/staff/p.knoppers">Peter Knoppers</a>
17   */
18  public final class FloatConstants
19  {
20      /** Utility class. */
21      private FloatConstants()
22      {
23          // utility class
24      }
25  
26      /**
27       * Number of constituent particles in a Mole; a.k.a. Avogadro's number. This value is exact since the 2019 redefinition of
28       * the SI base units.
29       */
30      public static final SIScalar AVOGADRO = SIScalar.of(6.02214076e23, "1/mol");
31  
32      /**
33       * Boltzmann constant in Joule per Kelvin (this value is exact since the 2019 redefinition of SI base units). See
34       * <a href="https://en.wikipedia.org/wiki/Boltzmann_constant">Wikipedia: Boltzmann constant</a>
35       */
36      public static final SIScalar BOLTZMANN = SIScalar.of(1.380649e-23, "kgm2/s2K");
37  
38      /**
39       * The Cesium 133 ground state hyperfine structure transition frequency. This value is exact since the 2006 redefinition of
40       * the SI base units.
41       */
42      public static final Frequency CESIUM133_FREQUENCY = Frequency.of(9192631770d, "1/s");
43  
44      /** Electrical charge of one electron. This value is exact since the 2019 redefinition of the SI base units. */
45      public static final ElectricalCharge ELECTRONCHARGE = new ElectricalCharge(-1, ElectricalChargeUnit.ATOMIC_UNIT);
46  
47      /**
48       * Mass of an electron. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This
49       * value of this physical constant has an uncertainty of 2.8e-40 kg.
50       */
51      public static final Mass ELECTRONMASS = Mass.of(9.1093837015e-31, "kg");
52  
53      /** ElectricalCharge of one proton. */
54      public static final ElectricalCharge PROTONCHARGE = new ElectricalCharge(1, ElectricalChargeUnit.ATOMIC_UNIT);
55  
56      /**
57       * Mass of a neutron. See <a href="https://en.wikipedia.org/wiki/List_of_physical_constants">Wikipedia List of physical
58       * constants</a>. This value of this physical constant has an uncertainty of 9.5e-37 kg.
59       */
60      public static final Mass NEUTRONMASS = Mass.of(1.6749274714e-27, "kg");
61  
62      /**
63       * Mass of a proton. See <a href="https://en.wikipedia.org/wiki/Physical_constant">Wikipedia Physical constant</a>. This
64       * value of this physical constant has an uncertainty of 5.1e-37.
65       */
66      public static final Mass PROTONMASS = Mass.of(1.67262192369e-27, "kg");
67  
68      /**
69       * Gravitational constant, a.k.a. Newtonian constant of gravitation. This is the 2018 best known approximation, which has an
70       * uncertainty 1.5e-15 m^3/kgs^2
71       */
72      public static final SIScalar G = SIScalar.of(6.67430e-11, "m3/kgs2");
73  
74      /** Speed of light in vacuum. This value is exact (since the 2006 redefinition of the SI base units). */
75      public static final Speed LIGHTSPEED = Speed.of(299792458, "m/s");
76  
77      /**
78       * Permeability of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permeability">Wikipedia, Vacuum
79       * permeability</a>. The uncertainty of this value is 1.9e-16N/A^2.
80       */
81      public static final SIScalar VACUUMPERMEABILITY = SIScalar.of(1.25663706212e-6, "kgm/s2A2");
82  
83      /**
84       * Permittivity of vacuum. See <a href="https://en.wikipedia.org/wiki/Vacuum_permittivity">Wikipedia Vacuum
85       * permittivity</a>. The uncertainty of this value is 1.3e-21 F/m.
86       */
87      public static final SIScalar VACUUMPERMITTIVITY = SIScalar.of(8.8541878128e-12, "s4A2/kgm3");
88  
89      /** Impedance of vacuum. */
90      public static final SIScalar VACUUMIMPEDANCE = VACUUMPERMEABILITY.times(LIGHTSPEED);
91  
92      /**
93       * Planck constant; ratio of a photon's energy and its frequency. This value is exact since the 2019 redefinition of the SI
94       * base units.
95       */
96      public static final SIScalar PLANCK = SIScalar.of(6.62607015e-34, "kgm2/s");
97  
98      /**
99       * The luminous efficacy Kcd of monochromatic radiation of frequency 540×10^12 Hz (540 THz). This is the frequency of a
100      * green-colored light at approximately the peak sensitivity of the human eye. This value is exact since the 2006
101      * redefinition of the SI base units.
102      */
103     public static final SIScalar LUMINOUS_EFFICACY_540THZ = SIScalar.of(683d, "cdsrs3/kg");
104 
105     /** Ratio of circumference of circle and its radius. */
106     public static final Dimensionless TAU = new Dimensionless(Math.PI * 2, DimensionlessUnit.SI);
107 
108     /** Reduced Planck constant, a.k.a. angular Planck constant; Planck constant divided by 2 pi. */
109     public static final SIScalar PLANKREDUCED = PLANCK.divide(TAU);
110 
111 }