crystMW {cryst}

Relative Crystallinity Calculation of X-Ray Diffraction Pattern of Starch by Bruckner Method

Description

Allow to calculate the relative crystallinity of starch by XRD. The basic concept of Bruckner approach involves obtaining a smoothed line that separates the amorphous and crystalline starch of an X-ray diffraction pattern. This smoothed line is achieved by applying a moving average smoothing method to the original pattern.

Usage

crystMW(pattern, N = 41, iter = 100)

Arguments

pattern

matrix. The matrix of X-ray diffraction pattern. The first row corresponds to Bragg angle 2\theta; the second row corresponds to intensity.

N

numeric. N length of the smoothing window (number of variables). Defaults to 41.

iter

numeric. Iter number of iterations. Defaults to 100.

Details

Calculate the relative starch crystallinity of XRD pattern by Bruckner method.

Value

An object of class crystMW, which is a list with the following components:

original

Original matrix of X-ray diffraction patterns.

background

Estimation of the background shape (curve of the amorphous starch).

corrected

Estimation of residual crystalline area (curve of the crystalline starch).

summary

Summary calculation of crystallinity. Total area under the curve of the diffraction pattern (A.U.); Amorphous area (A.U.); Crystalline area (A.U.); Relative crystallinity (%).

Author(s)

Claudio Pozo Valenzuela [aut, cre] and Saddys Rodriguez-llamazares [aut]

References

Bruckner, S. (2000). "Estimation of the background in powder diffraction patterns through a robust smoothing procedure." Journal of Applied Crystallography 33(3 Part 2): 977-979.

Examples

data(XRD)
# Convert data frame to matrix, select A-type starch
pattern <- as.matrix(t(XRD[,c("Bragg_angle","A")]))
# List of crystallinity components
crs <- crystMW(pattern, N = 41, iter = 100)
# Original matrix
original <- crs$original
# Background shape
background <- crs$background
# Curve of the crystalline starch
corrected <- crs$corrected
# Summary calculation of crystallinity
summary <- crs$summary