Indeterminate order rate equation kinetics

Function describing exponential decline from a defined starting value, with a concentration dependent rate constant.

IORE.solution(t, parent.0, k__iore, N)

Arguments

t

Time.

parent.0

Starting value for the response variable at time zero.

k__iore

Rate constant. Note that this depends on the concentration units used.

N

Exponent describing the nonlinearity of the rate equation

Note

The solution of the IORE kinetic model reduces to the SFO.solution if N = 1. The parameters of the IORE model can be transformed to equivalent parameters of the FOMC mode - see the NAFTA guidance for details.

Value

The value of the response variable at time t.

References

NAFTA Technical Working Group on Pesticides (not dated) Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media

Examples

  plot(function(x) IORE.solution(x, 100, 0.2, 1.3), 0, 2,
                                       ylim = c(0, 100))
  fit.fomc <- mkinfit("FOMC", FOCUS_2006_C, quiet = TRUE)
  fit.iore <- mkinfit("IORE", FOCUS_2006_C, quiet = TRUE)
  fit.iore.deS <- mkinfit("IORE", FOCUS_2006_C, solution_type = "deSolve", quiet = TRUE)

  print(data.frame(coef(fit.fomc), coef(fit.iore), coef(fit.iore.deS),
                   row.names = paste("model par", 1:3)))
#>             coef.fit.fomc. coef.fit.iore. coef.fit.iore.deS.
#> model par 1    85.87489063      85.874891          85.874890
#> model par 2     0.05192238      -4.826631          -4.826631
#> model par 3     0.65096665       1.949403           1.949403
#> 
  print(rbind(fomc = endpoints(fit.fomc)$distimes, iore = endpoints(fit.iore)$distimes,
              iore.deS = endpoints(fit.iore)$distimes))
#>              DT50    DT90 DT50back
#> fomc     1.785233 15.1479 4.559973
#> iore     1.785233 15.1479 4.559973
#> iore.deS 1.785233 15.1479 4.559973
#>