From 12a31f4c130c551f82232d9ef7dfb608bd52c53f Mon Sep 17 00:00:00 2001 From: Johannes Ranke Date: Tue, 27 Sep 2016 23:00:48 +0200 Subject: Reorganise repository using standard package layout --- R/SFO_actual_twa.R | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 R/SFO_actual_twa.R (limited to 'R/SFO_actual_twa.R') diff --git a/R/SFO_actual_twa.R b/R/SFO_actual_twa.R new file mode 100644 index 0000000..7facb6a --- /dev/null +++ b/R/SFO_actual_twa.R @@ -0,0 +1,36 @@ +# Copyright (C) 2015 Johannes Ranke +# Contact: jranke@uni-bremen.de +# This file is part of the R package pfm + +# This program is free software: you can redistribute it and/or modify it under +# the terms of the GNU General Public License as published by the Free Software +# Foundation, either version 3 of the License, or (at your option) any later +# version. + +# This program is distributed in the hope that it will be useful, but WITHOUT +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more +# details. + +# You should have received a copy of the GNU General Public License along with +# this program. If not, see + +#' Actual and maximum moving window time average concentrations for SFO kinetics +#' +#' @param DT50 The half-life. +#' @param times The output times, and window sizes for time weighted average concentrations +#' @export +#' @author Johannes Ranke +#' @source FOCUS (2014) Generic Guidance for Estimating Persistence and Degradation +#' Kinetics from Environmental Fate Studies on Pesticides in EU Registratin, Version 1.1, +#' 18 December 2014, p. 251 +#' @examples +#' SFO_actual_twa(10) +SFO_actual_twa <- function(DT50 = 1000, times = c(0, 1, 2, 4, 7, 14, 21, 28, 42, 50, 100)) +{ + k = log(2)/DT50 + result <- data.frame(actual = 1 * exp(-k * times), + twa = (1 - exp(-k * times))/(k * times), + row.names = times) + return(result) +} -- cgit v1.2.1