Add unit squareMetrePerCubicCentimetre
Opened this issue · 3 comments
Hi Hajo,
squareMetrePerCubicCentimetre shows surface area of material per its volume,
it is somewhat similar to squareMetrePerGram (which is already present in OM2).
Thanks,
Paul.
Hi Paul,
Thanx for the suggestion. I have just defined it. I did it in a simple way, without any comments yet, since I'm not sure yet if the unit would be restricted to surface area of material per volume, what would you think?
Cheers, Hajo
Hi Hajo,
Not sure what your question is about.
I faced this unit only once in my life, and don't really think I will see similar units in future.
One may say this unit is a reciprocalMeter with a coefficient, and there are plenty of properties with this unit (e.g. wavenumber).
But I don't think this is a good comparison. I think it is a one way conversion:
Every squareMetrePerCubicCentimetre is a reciprocalMeter - conversion of surface area per volume from non-standard to SI units,
but NOT every reciprocalMeter is a squareMetrePerCubicCentimetre - conversion may introduce a new physical meaning, i.e. change the physical property.
Is this what you think of?
I don't remember seeing a one-way unit conversion in OM-2 ontology (correct me if I am wrong).
Do you want to introduce something like "see also"/"also known as"/"to SI units" object property?
Paul.
Hi Paul,
Sorry for my late reply.
What I meant is: the use of the unit would not be restricted to only volumes of materials, I guess?
Well, I think in the experimental sciences such units are quite often used, so relevant.
I understand what you mean, mathematically indeed this unit is equivalent to the units that you suggest, but that is only mathematically. With other mathematical expressions of units we want to express certain kind of specifics, so it is very relevant to preserve that.
Units are expressed in terms of other units in OM, using the hasFactor and hasUnit properties, which should be used in combination. That I would already like to change in OM 3.0, probably reverting to something like the hasDefinition property in terms of a unit or a measure (e.g. '2.54 cm').
Usually these units are SI base units or compound units consisting of SI base units, but I would like to add all possible bilateral unit expressions (conversions if you like) in OM. Of course that requires a lot of effort; it should be done automatically, which also costs effort, but it is and remains on my wish list and I will make a start with this in the future, manually.
(So, no, not 'see also/etc.' but the present and future relations described above.)
Cheers, Hajo