A literal answer to your question is the [math-style=upright]
package option of unicode-math
, which you can switch on and off with the commands
\unimathsetup{math-style=upright}
\unimathsetup{math-style=ISO}
For example:
\documentclass[varwidth=10cm, preview]{standalone}
\usepackage{physics}
\usepackage[math-style=upright]{unicode-math}
\begin{document}
\begin{align*}
TDD &= \frac{18}{9} = 2' \\
TF &= TI-TDD = 25-2 = 23' \\
TR &= \frac{18-5}{9} = 2' \\
TT &= TI+TRT+TD+TRS = 25+2+5+1 = 33'
\end{align*}
\end{document}

That said, I wouldn’t recommend you use this technique. (Although I do recommend that you use unicode-math
if you’re allowed to!) The \mathrm
solution is still supported and will work fine.
I personally find it handy to declare something like \newcommand\TDD{\ensuremath{\mathop{\mathrm{TDD}}}}
and then write \TDD
in the equations. If you might for some reason want to write x \TDD
or \TDD \TI
instead of x \cdot \TDD
and \TDD \cdot \TI
, the \mathop
makes x TDD TI behave like log log x (that is, typeset like an operator name).
\documentclass[varwidth=10cm, preview]{standalone}
\usepackage[T1]{fontenc}
\usepackage{physics}
\newcommand\upvar[1]{\ensuremath{\mathop{\mathrm{#1}}}}
\newcommand\TD{\upvar{TD}}
\newcommand\TDD{\upvar{TDD}}
\newcommand\TF{\upvar{TF}}
\newcommand\TI{\upvar{TI}}
\newcommand\TR{\upvar{TR}}
\newcommand\TRS{\upvar{TRS}}
\newcommand\TRT{\upvar{TRT}}
\newcommand\TT{\upvar{TT}}
\begin{document}
\begin{align*}
\TDD &= \frac{18}{9} = 2' \\
\TF &= \TI-\TDD = 25-2 = 23' \\
\TR &= \frac{18-5}{9} = 2' \\
\TT &= \TI+\TRT+\TD+\TRS = 25+2+5+1 = 33'
\end{align*}
\end{document}
This is just like typing \log
or \sin
. An existing shorthand for this is \operatorname{TDD}
from amsmath
.
\mathrm{TDD}
although it is possible to change the default (probably an answer on site already I'll look... – David Carlisle Feb 8 at 14:11\mathrm{TR}
and\mathrm{TDD}
(not\text
) but you could do this, replacing\mathtt
by\mathrm
tex.stackexchange.com/a/63000/1090 – David Carlisle Feb 8 at 14:15&
sign, another one after it). Look here i.imgur.com/hqF3sLJ.png – sound wave Feb 8 at 14:23\mathrm
just to be around each identifier not spanning&
) If you get an error such as! Missing } inserted.
do not even look at the pdf output, it is just a possible debugging aid, tex makes no attempt at making sensible typeset output after an error. – David Carlisle Feb 8 at 14:28align
should never be in math mode so I don't see how you could get that error or have formulas before the alignment? The code in my answer generates no error. – David Carlisle Feb 8 at 14:41