Treesearch

As wood is exposed to high temperatures, pyrolysis begins, permanently altering the material properties as volatiles and char are formed. The rate at which char is formed is used to predict failure times for timber members and has been shown to be inversely related to the density of the wood. Because the density is a function of local exposure temperatures, it is inherently difficult to measure and typically is simplified to a single bulk value for either unmodified wood or the density of wood and char. Here, we report the use of two fast, simple density measurement techniques to characteri...

Brown rot fungi are primary decomposers of wood and litter in northern forests. Relative to other microbes, these fungi have evolved distinct mechanisms that rapidly depolymerize and metabolize cellulose and hemicellulose without digesting the more recalcitrant lignin. Its efficient degradative system has therefore attracted considerable attention for the development of sustainable biomass conversion technologies. However, there has been a significant lack of genetic tools in brown rot species by which to manipulate genes for both mechanistic studies and engineering applications. To...

Wood stiffness (modulus of elasticity, MOE) is an important property for conifer wood, with the variability in MOE largely being a function of both the specific gravity (SG) (wood density) and the angle of the microfibrils within the S2 layer of longitudinal tracheids. Rapid analysis techniques can be used together to quantify MOE; while SG can be determined with relative ease, this is not the case for microfibril angle, requiring expensive X-ray diffraction equipment. An alternative to microfibril angle is to measure longitudinal acoustic velocity. The objective of this study was to...

A new mold growth model was developed to aid in moisture risk assessment of wood-based building assemblies. This proposed simple model relies on several features common to existing mold growth models but combines them in a new way with improved predictive power. Structurally the model is based on a dose-response relationship. Hygrothermal conditions conducive to mold growth are represented using a mold germination isopleth, i.e., a critical relative humidity curve as a function of temperature. The dose at a given time step depends on the difference between surface relative humidity and the...

Cross-laminated timber (CLT) is an increasingly popular wood-based alternative for large building applications. CLT panels are typically not treated due in part to a perceived lack of efficient and effective methods for treating large panels and a lack of information on what effect treatment processes may have on the panels’ mechanical properties. We propose that treating CLT panels with borate solution, applied under vacuum in flexible bags, could provide a practical and effective option for providing preservative protection for interior applications. Samples were cut from commercially...

In September, month-over-month data were negative in several categories. Year-over-year data were similar. Single-family permits and starts decreased again, month-over-month and year-over-year. The impact of increasing borrowing costs and slow income growth combined with still elevated house prices resulted in a major obstacle for new and existing house sales. September was the eighth consecutive monthly decrease for existing house sales. Single-family construction spending decreased for the fourth straight month.

United States Department of Defense munitions wood packaging materials (WPMs) are currently dip-treated with preservatives to protect the wood against decay fungi and termites. However, recent observations of mold on WPMs prompted research to evaluate the effectiveness of adding moldicides to the wood preservatives that are typically used on WPMs. Controlling moisture is the most effective way to prevent mold growth, but this is not always possible during WPM handling and storage. For this study, moldicides were selected based on compatibility with existing wood preservatives, commercial...

The interest in non-formaldehyde adhesives has reinvigorated studies using proteins from plant and animal sources, with an emphasis on plant-based sources, especially the oilseed plants such as soybean. Although animal-based sources have received much less attention, and ovalbumin from egg whites has not been studied at all, it provides a surprising low viscosity and high wet strength as a wood adhesive. Of the animal and plant proteins used in the past, egg protein has been used for centuries as a binder in tempera, for book illumination, and for gilding, but not as a water-resistant wood...

Maleic acid (MA), a solid dicarboxylic acid can be obtained from renewable lignocellulose, was used to extract lignin through flow through (FT) process for the first time. Due to the high boiling point and flash point of MA, the FT process was carried out at atmospheric pressure without VOCs release and explosion risk. 50 wt% MA aqueous solution could extract 60 % lignin from birch wood, and the dilution factor for precipitating lignin was only 3. MA-extracted lignin preserved more than 80 % of β–O–4 bonds and a monophenol yield (＞30 %) comparable to that of milled wood lignin was obtained...

This study compared oxidative delignification of birch kraft pulp fibers to pulp fibers from acid hydrotropic fractionation (AHF) using p-toluenesulfonic acid (p-TsOH). Under oxygen delignification at 20% consistency, AHF pulps with lower hemicellulose content showed higher delignification than kraft pulps with similar lignin content despite its residual lignin (cellulosic enzymatic lignin, CEL) being less reactive with fewer β-O-4 ether aryl linkages based on 2D13C-1 H nuclear magnetic resonance (NMR) spectroscopy. The water retention value (WRV) of AHF pulp fibers, a measure of fiber...