seedwater (version 2.0)

dryingmodels: Modeling Seed Drying Kinetics

Description

An interactive function to fit nonlinear models for seed drying kinetics.

Usage

dryingmodels(moisture, time)

Arguments

moisture

a numeric vector containing values of seed water content of weight of seed sample. See Details.

time

a numeric vector containing values of drying time.

Value

An object of class nls containing the parameter estimates.

Side Effects

An interactive graphic is displayed for selecting the model and the initial values for the parameters.

Details

dryingmodels is set to fit curves of moisture ratio (MR) rather than moisture. It is automatically calculated through the equation:

$$ MR = \frac{\code{moisture} - Mf}{Mi - Mf} $$

where \(Mi\) and \(Mf\) are the initial and final values of seed moisture.

These are the currently available models:

(Page) \( MR = exp(-K * x^n) \)

(Henderson and Pabis) \( MR = A * exp(-K * x) \)

(Henderson and Pabis modified) \( MR = A * exp(-K * x) + b * exp(-K0 * x) + exp(-K1 * x) \)

(Midilli) \( MR = A * exp(-K * x^n) + b*x \)

(Diffusion approximation) \( MR = A * exp(-K * x) + (1 - A) * exp(-K * b * x) \)

(Two terms exponential 1) \( MR = A * exp(-K0 * x) + b * exp(-K1 * x) \)

(Two terms exponential 2) \( MR = A * exp(-K * x) + (1 - A) * exp(-K * A * x) \)

(Logarithmic) \( MR = A * exp(-K * x) + b \)

(Thompson) \( MR = exp(-A - sqrt(A^2 + 4 * b * x))/(2 * b) \)

(Newton) \( MR = exp(-K * x)\)

(Verma) \( MR = A * exp(-K * x) + (1 - A) * exp(-K1 * x)\)

(Wang and Sing) \( MR = 1 + A * x + b * x^2\)

where \(x\) represents time and \(A\), \(K\), \(n\), \(b\), \(K0\) and \(K1\) are the model parameters.

See Also

nls, soakingmodels

Examples

# NOT RUN {
data(waterloss)
if (interactive()) {
   res <- with(waterloss, dryingmodels(moisture = WaterContent, time = Time))
   summary(res)
}

# End (not run)
# }