Degree Type

Dissertation

Date of Award

1994

Degree Name

Doctor of Philosophy

Department

Forestry

First Advisor

Floyd G. Manwiller

Abstract

Compositional images constructed from characteristic x-ray signals generated within the electron microscope possess key advantages over traditional energy dispersive static probe analyses or conventional analog x-ray dot maps for assessing elemental distribution in preservative-treated wood. Digital images are produced by "stepping" the electron beam across the sample in a prescribed format and collecting x-ray information at each pixel point of the array. The various elements present are displayed on a cathode ray tube (CRT), and the peak intensities are stored on disk for subsequent processing and analysis. By assigning a different color to each element, images are produced that correspond to the distribution of the various elements. Further, by relating the brightness of a color to elemental concentration, the images are useful for assessing the concentration gradients within and across cell wall boundaries. The data is further corrected for deadtime losses and continuum contributions to provide net intensity images;Issues relating to performing fully quantitative analyses are addressed as well as alternative specimen preparation procedures;Material for the study consisted of southern pine sapwood stakes treated with copper and sodium dimethyldithiocarbamate.

DOI

https://doi.org/10.31274/rtd-180813-9829

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Glenn M. Oren

Language

en

Proquest ID

AAI9424248

File Format

application/pdf

File Size

125 pages

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