diff options
Diffstat (limited to 'docs/articles/twa.Rmd')
-rw-r--r-- | docs/articles/twa.Rmd | 57 |
1 files changed, 0 insertions, 57 deletions
diff --git a/docs/articles/twa.Rmd b/docs/articles/twa.Rmd deleted file mode 100644 index 60188223..00000000 --- a/docs/articles/twa.Rmd +++ /dev/null @@ -1,57 +0,0 @@ ---- -title: Calculation of time weighted average concentrations with mkin -author: Johannes Ranke -date: "`r Sys.Date()`" -bibliography: references.bib -vignette: > - %\VignetteEngine{knitr::rmarkdown} - %\VignetteIndexEntry{Calculation of time weighted average concentrations with mkin} - %\VignetteEncoding{UTF-8} ---- - -Since version 0.9.45.1 of the 'mkin' package, a function for calculating -time weighted average concentrations for decline kinetics (*i.e.* only -for the compound applied in the experiment) is included. - -Time weighted average concentrations for the DFOP model are calculated using -the formulas given in the FOCUS kinetics guidance [@FOCUSkinetics2014, p. 251]: - -SFO: - -$$c_\textrm{twa} = c_0 \frac{\left( 1 - e^{- k t} \right)}{ k t} $$ - -FOMC: - -$$c_\textrm{twa} = c_0 \frac{\beta}{t (1 - \alpha)} - \left( \left(\frac{t}{\beta} + 1 \right)^{1 - \alpha} - 1 \right) $$ - -DFOP: - -$$c_\textrm{twa} = \frac{c_0}{t} \left( - \frac{g}{k_1} \left( 1 - e^{- k_1 t} \right) + - \frac{1-g}{k_2} \left( 1 - e^{- k_2 t} \right) \right) $$ - -Often, the ratio between the time weighted average concentration $c_\textrm{twa}$ -and the initial concentration $c_0$ - -$$f_\textrm{twa} = \frac{c_\textrm{twa}}{c_0}$$ - -is needed. This can be calculated from the fitted initial concentration $c_0$ and -the time weighted average concentration $c_\textrm{twa}$, or directly from -the model parameters using the following formulas: - -SFO: - -$$f_\textrm{twa} = \frac{\left( 1 - e^{- k t} \right)}{k t} $$ - -FOMC: - -$$f_\textrm{twa} = \frac{\beta}{t (1 - \alpha)} - \left( \left(\frac{t}{\beta} + 1 \right)^{1 - \alpha} - 1 \right) $$ - -DFOP: - -$$f_\textrm{twa} = \frac{1}{t} \left( - \frac{g}{k_1} \left( 1 - e^{- k_1 t} \right) + - \frac{1-g}{k_2} \left( 1 - e^{- k_2 t} \right) \right) $$ - |