Tageldin Hussein Nasroun
Wood is natural and a very variable material. Much of this variability is attributed to the cellular structure of wood. Stereological techniques were introduced as fast, easy and adequately accurate methods for quantitative structural characterization of wood. The techniques rely on counts rather than direct measurements. In this investigation systematic point counts, boundary intersection counts and feature counts were made on projected transverse sections of wood from trees of Eucalyptus camaldulensis var. obtusa of different ages. Intersection counts and feature counts were also made on macerated fibers. These stereological counts were used for obtained wood structural parameters such as volume fractions of different wood cells, cell wall and lumen volume fractions, cell cross-sectional dimensions, ratios of these dimensions and fiber length. The analysis revealed significant differences between the wood of trees of different ages in most parameters; while within-tree variations were significant only for a few parameters. Many of these variations, however, did not follow any special trend, which might be attributed to the intrinsic patterns of variations inherited in this species.
E.M. Abdelrahman and Sh. M. Sharafeldin
A new approach to depth determination from normalized moving average residual gravity anomalies is developed. The depth estimation has been transformed into a solution of a nonlinear equation of the form z = f(z). Formulas have been derived for a sphere, horizontal cylinder, vertical cylinder, and vertical fault. The method can be applied to residuals and Bouguer gravity data of a short profile length. The method is applied to synthetic data with an without random errors and its validity is tested on two field examples: (1) The Abu Roash Dome gravity anomaly, west of Cairo, Egypt and (2) The Louga gravity anomaly, West Senegal, in West Africa.