Treesearch

Accelerated weathering of wood surfaces coated with hexadecyltrimethoxysilane (HDTMOS) in the presence of methyltrimethoxysilane (MTMOS) by the sol-gel process was investigated. The sol-gel process allowed the deposition of a covalently bound thin layer of polysiloxane networks on the wood surface that was resistant to water sorption and water leaching. The rate of weight loss resulting from surface erosion and the extent of surface color loss caused by photo- nduced discoloration were decreased for coated specimens compared to uncoated specimens.

Agave bagasse — used in tequila production — has value as bulking agent in composting trials with abattoir residuals, which are currently being landfilled.

In this study, experimental bending tests were performed on nominal 4-by 8-inch (actual 89-mm by 191-mm)lumber members to determine how a notch and holes drilled in the wide face affect edge wise bending strength. Holes were drilled at the midspan in three locations relative to the edge. The results appear to justify an allowable hole one-half the allowable knot size that is currently permitted for cedar in No. 1 Beams & Stringer grade. Furthermore, the data indicate that hole location may be as important as hole size. A1-inch (25.4-mm)hole had about the same effect on strength as a...

An extractive compound with a novel ring system was isolated from the wood of Salix alba and was given the name Salucci. The compound was primarily identified from the 1D NMR, 2D NMR and LC-MSMS data and the structure investigated through reactions and derivatizations.

The remarkable deformability of wood in a moist environment resembles that of ductile metals. A combination of traditional mechanical tests and cutting-edge diffraction experiments reveal the molecular mechanism that determines such behaviour.

Efforts to develop new environmentally friendly wood preservatives are seriously handicapped by the extended time period required to carry out the evaluation needed to establish confidence in the long term performance of new preservative systems. Studies in our laboratory have shown that using strength loss as a measure of the extent of wood decay makes it possible to detect the early stages of decay that results from non-ezymatic reactions. We have developed specialized equipment and techniques that have applications for both above ground and soil contact preservative systems. By coupling...

This paper compares the so-called exact approach for obtaining confidence intervals on normal distribution coefficients of variation to approximate methods. Approximate approaches were found to perform less well than the exact approach for large coefficients of variation and small sample sizes. Web-based computer programs are described for calculating confidence intervals on coefficients of variation for normally and lognormally distributed data.

The goal of our research is to promote healthy and sustainable forests by developing value-added uses for curved and small-diameter trees. In typical North American logging or thinning operations, much of this low- value timber is felled and left on the ground, chipped, or burned because most mills are not equipped to handle it. By understanding the fundamental processing requirements for and the mechanical properties of curved and small-diameter material, we can gain insight into possible options for using this resource. Through cooperative efforts with industry, universities, and...

The phenomenon of “self-absorption” was found to exist in the FT-Raman spectra of cellulose and thermomechanical pulp (TMP), but not in the spectrum of milled wood lignin. For cellulose and TMP, the effect was responsible for reducing the intensity of the Raman bands in the C-H stretch region. Several factors including sampling position, sample thickness, and moisture content of the sample affected the band suppression due to self-absorption. The intensity reduction, detected only in the C-H stretch region, was largely due to the fact that the aliphatic- and water- hydroxyl groups have...

The natural durability of 10 lesser known, commercially available Bolivian hardwoods to decay fungi was evaluated using a modified ASTM soil-block analysis for 12 weeks. The blocks were then retested for an additional 12 weeks to determine their level of decay resistance, as determined by percentage of weight loss. Astronium urundeuva, Caesalpinia cf. pluviosa, Schinopsis quebrachocolorado, and Tabebuia sp. (lapacho group) were found to be highly resistant to decay; Amburana cearensis, Anadenanthera colubrina (syn: A. macrocarpa), Aspidosperma cylindrocarpon, Diplotropis purpurea, and...