a b s t r a c tThe objective of the study was to investigate the influence of heat treatment and exposure time on surface roughness, wettability, shear strength and hardness of rubberwood, Eastern redcedar and red oak samples. The anatomical structure of each species was also observed using scanning electron microscope (SEM). All specimens were exposed to two different temperature levels, namely 120°C and 190°C for 2 and 8 h. Red oak samples had the most enhanced surface quality along with less wettability characteristics followed by rubberwood and Eastern redcedar specimens as function of increased heat exposure. On the other hand, it appears that heat exposure adversely affected shear strength and hardness properties of all three types of samples. These two properties of heat treated samples had reduction values ranging from 52.7% to 69.4% and 10.8% to 33.3%, respectively as compared to those of control samples.Published by Elsevier Ltd.

The objective of this study was to investigate the moisture content (MC), density, and amount of extractives along the height of a 32-year-old oil palm stem. The extractives were removed following TAPPI standards T-207 and T-280 for water solubility and acetone extractives. The results showed that the MC of the palm stem increased from the outer towards the inner section, while the density decreased. Along the tree height, the MC was found to increase from the bottom to the middle part, but slightly decreased towards the top. An inverse trend was obtained for the density distribution along the tree height. The results of the extractive separation showed that the middle and center sections of the oil palm stem contained the highest amount of extractives irrespective of the types of solvent. The highest amount of extractives was obtained from hot water extraction, followed by cold water and acetone extractions. The lowest amount of extractives was located at the bottom outer section of the oil palm stem which ranging from 2.0 to 9.2%, whereas the middle and center sections contained a greater amount of extractives ranged from 4.6 to 32.8% regardless of the type of solvent used.

In this research, variations in longitudinal permeability of oil palm (Elaeis guineensis Jacq) wood were investigated. Panels were prepared from bark to pith with the study carried out on 3 parts of the transverse surface: outer, middle, and inner. Microscopic observations were done to determine the anatomical properties to establish its theoretical permeability using Poiseuille's equation. Results showed that the middle part of the transverse surface of oil palm wood had the highest theoretical, water, and gas permeability values in the longitudinal direction followed by the inner and outer parts. A decrease in the length of samples resulted in an increase in the permeability of the samples. For all parts, theoretical permeability values were the highest followed by water and gas permeability Lower gas permeability values in comparison to water permeability indicates that oil palm wood is prone to drying defects and is more difficult to treat with chemicals after drying.

No abstract