View source: R/max_twa_parent.R

max_twa_parent | R Documentation |

This function calculates maximum moving window time weighted average
concentrations (TWAs) for kinetic models fitted with `mkinfit`

.
Currently, only calculations for the parent are implemented for the SFO,
FOMC, DFOP and HS models, using the analytical formulas given in the PEC
soil section of the FOCUS guidance.

```
max_twa_parent(fit, windows)
max_twa_sfo(M0 = 1, k, t)
max_twa_fomc(M0 = 1, alpha, beta, t)
max_twa_dfop(M0 = 1, k1, k2, g, t)
max_twa_hs(M0 = 1, k1, k2, tb, t)
```

`fit` |
An object of class |

`windows` |
The width of the time windows for which the TWAs should be calculated. |

`M0` |
The initial concentration for which the maximum time weighted average over the decline curve should be calculated. The default is to use a value of 1, which means that a relative maximum time weighted average factor (f_twa) is calculated. |

`k` |
The rate constant in the case of SFO kinetics. |

`t` |
The width of the time window. |

`alpha` |
Parameter of the FOMC model. |

`beta` |
Parameter of the FOMC model. |

`k1` |
The first rate constant of the DFOP or the HS kinetics. |

`k2` |
The second rate constant of the DFOP or the HS kinetics. |

`g` |
Parameter of the DFOP model. |

`tb` |
Parameter of the HS model. |

For `max_twa_parent`

, a numeric vector, named using the
`windows`

argument. For the other functions, a numeric vector of
length one (also known as 'a number').

Johannes Ranke

FOCUS (2006) “Guidance Document on Estimating Persistence and Degradation Kinetics from Environmental Fate Studies on Pesticides in EU Registration” Report of the FOCUS Work Group on Degradation Kinetics, EC Document Reference Sanco/10058/2005 version 2.0, 434 pp, http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics

```
fit <- mkinfit("FOMC", FOCUS_2006_C, quiet = TRUE)
max_twa_parent(fit, c(7, 21))
```

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