I was looking up something on the NIST (National Institute of Standards and Technology) website the other day and ran across thermocouple polynomials. I wondered what that could be, assuming “thermocouple” was a metaphor for some algebraic property. No, it refers to physical thermocouples. The polynomials are functions for computing voltage as a function of temperature, and temperature as a function of voltage, for a variety of types of thermocouples. See the NIST ITS-90 Thermocouple Database.

I keep running into NIST’s eclectic collection of useful information. Three examples:

- My post on Koide’s coincidence references their list of physical constants.
- My post on naming elliptic curves mentions NIST and their FIPS (Federal Information Processing Standards) publications.
- My post on testing the PCG random number generator made use of the NIST Statistical Test Suite.

I wonder what’s going to take me back to NIST next.

You should definitely checkout NIST REFPROP and multi-parameter (aka polynomial) Helmholtz Equations of State, if you like polynomials:

https://www.nist.gov/srd/refprop

This made me think of “blend laws” in refineries. If you have n blend stocks, each with m attributes (octane, RVP, %sulfur, %benzene), what are the properties of a resulting blend? How do you predict / plan / optimize / control the properties of a blend? This is a huge driver of the economics of a refinery. See for example https://inside.mines.edu/~jjechura/Refining/11_Blending_Optimization.pdf.