Gunther and Pat agreed on:
>>> Either way, maximum allowable temperature and actual temperature are both
>special kinds of temperatures.
>>>
Matthew West wrote:
> MW: Then I ask you how I know when I look at a temperature whether it is a
>maximum allowable one or not.
> (01)
If you ever succeed in "looking at a temperature", tell us all how you
did it.
Temperature is a class/category of measurable physical phenomena. So to
look at one, you have to pick a physical phenomenon to measure, and you
should presumably know whether what you were measuring was an actual
temperature or a "maximum allowable temperature". I would assume that
you measured the latter as the last successful temperature measurement
before the device exploded or imploded or turned into a pumpkin. (02)
In engineering practice, BTW, that is more or less what is done. You
take a number of samples and expose them to increasing temperatures
until they degenerate in some way. Then you assign the smallest such
value (possibly with a safety factor) to the class as "maximum allowable
temperature". But note that this stated value is not actually the
measured value of a particular quantity. It is an "assigned property"
-- a property that is accidental to a use or role or situation. (03)
I would argue that that property is a "use of a quantity", but it is not
clearly a "quantity" in the sense of "particular quantity" or
"measurable quantity". The "measurable quantity" with that name is the
temperature at which that individual device actually fails, and you can
only measure that by observing the failure. The "maximum allowable
temperature" is (at best) an attribute whose value is a "quantity
magnitude" -- an abstract "quantity", or more simple an attribute whose
value is stated as a "quantity value". (04)
If this is the distinction between "direct" ("measurable") and
"indirect" ("assigned"), I don't see how it is relevant to an ontology
for units of measure, as distinct from some general ontology for uses of
quantities and quantity values.
"We only see that the missiles go up; where they come down is not our
department." ;-) (05)
-Ed (06)
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Manufacturing Systems Integration Division
100 Bureau Drive, Stop 8263 Tel: +1 301-975-3528
Gaithersburg, MD 20899-8263 FAX: +1 301-975-4694 (07)
"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority." (08)
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