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JMFA--a Graphically Interactive Java Program that Fits Microfibril Angle X-ray Diffraction Data

出版	U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, 2001
URL	http://books.google.com.hk/books?id=KAp7thrxlHoC&hl=&source=gbs_api
EBook	FULL_PUBLIC_DOMAIN

註釋Because much of our future timber resource is expected to come from short rotation plantations, we need to develop silvicultural practices that will improve the quality of the timber coming from these plantations. Short rotation plantations tend to produce timber with a higher percentage of juvenile wood, which has substantially lower mechanical property values than does mature wood. Measuring the microfibril angle (MFA) of wood gives important clues about the characteristics of the wood and can be used as a silvicultural tool to improve the quality of a plantation. In this report, we discuss a graphically interactive Java computer program that permits a user to estimate MFA from X-ray diffraction profiles. Given an MFA and a wood cell rotation pair (m, a), this program makes use of Cavegass theory to predict the locations of the eight high intensity X-ray spots on the back plane. Nonlinear least squares techniques are then used to find the (m, a) pair that yields a broadened form of the eight spots that best fits the empirical X-ray diffraction data. The program can be run as an applet over the World Wide Web, or it can be downloaded and run as an application on a usergass own machine. Because this program is based on a more complete physics model than earlier programs, we expect that it will yield more accurate MFA estimates. Preliminary comparisons of the new programgass MFA estimates with microscopy based estimates are encouraging. A complete evaluation of the accuracy of the programgass estimates will appear in a subsequent paper.