Temperature in Mathcad

Question

See http://communities.ptc.com/docs/DOC-3251

ValeryOchkov · Accepted Answer

One compromise:ELSID wrote:Your not quite a diamond member ... YETYes you can do what you've done, BUT (i know, I just negated everything before the but), you can no longer use C or F as they are now "re-defined".The definition in Mathcad of using DT works. As for your re-definition, the built-in DT values are DC=K and DF=(5/9)K and I can continue to use C or F without issues. I cannot emphasize enough that this works with papers, especially to clients and QA/QC staff who may not be as technically competent. They understand D (delta) is a change and the units after is universally accepted. If this is a petition for PTC to eliminate the DT "unit as it currently stands, I vote to keep the status quo as my pee-wee non- PhD, diamond member, or hero of the month brain understands it clearly!Maybe you're over thinking it Valery I often find that educated engineers and good students usually a) know what it is default, which is widely used in engineering, c) know what is temperature and c) have ... sense of humor In the book from NIST and ASME (see the cover below) I see only °F but not deltaF in thermal conductivity unit and °R but not deltaF as entropy or (isobaric or isohoric) heat capacity units! And second and last!The main topic of this my messege http://communities.ptc.com/docs/DOC-3251was not "conservative American and British people" but two temperature scale - ITS-68 and ITS-90.PSAn old joke.Father and son walking through Paris.- Dad, who built the tower?- Engineer Eiffel.- It's like my mother - an engineer?- No, my son, your mother is a lead engineer!

ELSID · Answer

Valery,This is a "unit" in 14 and 15 unter temperature as well. I use it all the time. It turns temperature into a liniar problem. On my Heat Transfer coefficients or equations, the "text book" formulas typically show a "change in temperature" by using the degrees F or degrees C. In my opinion, showing it as delta or change of temperature is correct. Scroll through some of my worksheets and you will see what I mean.Example: 100C - 80C needs to equal 20C and not -253.15C. DT is a change in temperature. If we use the "standard "degree F", the result is clearly wrong.Maybe a better request is to lump miscelaneous factors and scale units (e.g. DT, dB) into it's own category since they are not a true unit. In this case, the deltas are obviously defined as DC=K (kelvin) and DF=(5/9)K.

Sign up

Please use your PTC eSupport account.

Welcome to the PTC Community

Please use your PTC eSupport account.