Intercept method

Abstract: Accurate measurements of grain size are required to underpin development of models to predict properties, particularly of hybrid and multiphase materials. The conventional method for WC grain size determination in WC/Co is to use linear intercept measurements from light microscope or scanning electron microscopic images, usually requiring lengthy manual measurements, and subjective interpretation of grain boundary positions according to the level of etching and change in contrast. The possibilities offered by electron backscattering diffraction (EBSD) for improving the characterisation of both the WC and Co phase size, and contiguity between them, has been investigated. Samples covering a range of grain sizes have been examined by both EBSD and conventional methods to determine mean values and size distributions, with a special emphasis on the measurement of small grains. Diameters determined by both area (to give a circle equivalent diameter) and linear intercept from EBSD data are compared with the SEM image linear intercept method. It is shown that although the EBSD method is automated, great care must be taken in data analysis to identify and handle consistently small size values. If care is taken in the data handling then a good correlation can be shown between the EBSD and optical techniques.

Abstract: Question: The optimal use of the point intercept method (PIM) for efficient estimation of plant biomass has not been addressed although PIM is a commonly used method in vegetation analysis. In this study we compare results achieved using PIM at a range of efforts, we assess a method for calculating these results that are new with PIM and we provide a formula for planning the optimal use of PIM. Location: Northern Norway. Methods: We collected intercept data at a range of efforts, i.e. from one to 100 pins per 0.25 m2 plots, on three plant growth forms in a mountain meadow. After collection of intercept data we clipped and weighed the plant biomass. The relationship between intercept frequency and weighed biomass (b) was estimated using both a weighted linear regression model (WLR) and an ordinary linear regression model (OLR). The accuracy of the estimate of biomass achieved by PIM at different efforts was assessed by running computer simulations at different pin densities. Results: The relations...