Change Log
Version 2.0
List of Issues Resolved
 Emergency minor release 2.0.1 on 13NOV2015 to fix the exponent of Planck's constant. #175
 ucumessence.xml had elements in no name space. This was obviously a bug. It was resolved, not an emergency, but would have been more difficult to hold this minor fix back until 2.1 #157
Version 1.9
List of Issues Resolved
New units
tex  1  g/km  metric  tex

[den]  1  g/9/km  nonmetric  Denier

[anti'Xa'U]  1  1  nonmetric  arbitrary anti factor Xa unit

[EID_50]  1  1  nonmetric  arbitrary 50% embryo infectious dose

[Amb'a'1'U]  1  1  nonmetric  arbitrary allergen unit for Ambrosia artemisiifolia

[Lf]  1  1  nonmetric  arbitrary Limit of flocculation

[D'ag'U]  1  1  nonmetric  arbitrary Dantigen unit

[FEU]  1  1  nonmetric  arbitrary fibrinogen equivalent unit

[ELU]  1  1  nonmetric  arbitrary ELISA unit

[EU]  1  1  nonmetric  arbitrary Ehrlich unit

[foz_m]  30  mL  nonmetric  metric fluid ounce

[cup_m]  240  mL  nonmetric  metric cup

[tsp_m]  5  mL  nonmetric  metric teaspoon

[tbs_m]  15  mL  nonmetric  metric tablespoon

[oz_m]  28  g  nonmetric  metric ounce

[degR]  5  K/9  nonmetric  degree Rankine

Changed Units
Exact Constants
The following units are modified to turn constants which were stated of limited precision to exact. This is indicated by removing the decimal point from the number. If a number has a decimal point, it is considered having this number of significant digits, hence limited precision. If there is no decimal point (and magnitude adjusted in the exponent) it is considered exact.
[g]  980665e5 (was: 9.80665)  m/s2  metric  standard acceleration of free fall

m[H2O]  980665e5 (was 9.80665)  kPa  metric  meter of water column

Ci  37e9 (was: 3.7e10)  Bq  metric  Curie

[car_m]  2e1 (was: 0.2)  g  nonmetric  metric carat

Corrected Constants
[Ch]  1  mm/3 (was: mm/[pi])  nonmetric  Charrière

AU  149597.870691  Mm  nonmetric  astronomic unit

[drp]  1  ml/20 (was: ml/12)  nonmetric  drop

Version 1.8.2
The major change of this release is the establishment of a class of "arbitrary units" which are no longer simply dimensionless. This is to protect the false assumption that one could convert measurement values expressed in some arbitrary unit into one in another arbitrary or dimensionless units.
Version 1.8
List of Issues Resolved
New units:
[wood'U]  1  mm[Hg].min/L  nonmetric  Wood unit

[IU]  1  [iU]  metric  arbitrary international unit

[BAU]  1  1  nonmetric  arbitrary bioequivalent allergen unit

[AU]  1  1  nonmetric  arbitrary allergen unit

[PNU]  1  1  nonmetric  arbitrary protein nitrogen unit

B[10.nV]  *  2lg(10 nV)  metric  bel 10 nanovolt
