Treesearch

Wildfires are getting extreme and more frequent because of increased fuel loads in the forest and extended dry conditions. Prevention of wildfire by fuel treatment methods will generate forest residues in large volumes, which in addition to available logging residues, can be used to produce biofuels and bioproducts. In this study, the techno-economic assessment of three portable systems to produce woodchips briquettes (WCB), torrefiedwoodchips briquettes (TWCB) and biochar from forest residues were evaluated using pilot-scale experimental data. A discounted cash flow rate of return method...

It has been common practice to assume that a two-parameter Weibull probability distribution is suitable for modeling lumber strength properties. In a series of papers published from 2012 to 2018, Verrill et al. demonstrated theoretically and empirically that the modulus of rupture (MOR) distribution of a visual grade of lumber or of lumber that has been “binned” by modulus of elasticity (MOE) is not a twoparameter Weibull. Instead, the tails of the MOR distribution are thinned via “pseudo-truncation.” The theoretical portion of Verrill et al.’s argument was based on the assumption of a...

Bolted/pinned joints in orthotropic composite materials have received considerable attention over the years. Bolt fastening is one of the most commonly used methods to connect wood to wood and/or wood to steel, etc. Stresses at such connections can be the “Achilles’ heel”, causing structural failures. Notwithstanding the challenges in stress analyzing bolted joints, their advantages and widespread use motivate developing ability to optimize their design. Acknowledging the above, a finite element code is combined here with a screening optimization algorithm to optimize a bolt-hole pattern...

While research of Cross-Laminated Timber (CLT) structures prioritizes force-based design for earthquake hazards, this project navigates a complementary displacement-based route—charted by United States building code provisions for seismic isolation. Curvilinear cuts to the load-bearing edges of stock CLT panels enable walls to roll through pendulum motion. Elliptical geometry provides the mechanism to lift supported storeys, passively self-centre through oscillatory damping, and avert damage to the panel corners. Wider elliptical profiles reliably negate residual displacements, as a...

Meticulous chemical analysis of decaying xylem and linking it to corresponding anatomical modification at the cellular level can improve our understanding of the decay process. The aim of this study was to monitor the histological, chemical, photochemical, and progression of wood degradation by two white-rot fungi at different intervals. Oriental beech wood (Fagus orientalis) blocks were exposed to Pleurotus ostreatus and Trametes versicolor to investigate the degradation capabilities of these two fungi. Light microscopy was used to study the decay patterns in wood. Decayed wood samples...

The use of 50% concentration and 10% concentration hydrogen peroxide were evaluated for chemical and mechanical pulp bleach plants at storage and at point of use. Several dangerous occurrences have been documented when the supply of 50% peroxide going into the pulping process was not stopped during a process failure. Startup conditions and leaking block valves during maintenance outages have also contributed to explosions. Although hazardous events have occurred, 50% peroxide can be stored safely with proper precautions and engineering controls. For point of use in a chemical bleach plant,...

Wood decay fungi are any species of fungi that utilise the structural components of wood as a source of nutrients. They comprise a very diverse group and have a worldwide distribution normally wherever trees are found. Wood decay fungi are vital to ecosystem functioning as they facilitate the decomposition of woody materials into soil. Wood decay fungi are also major contributors to damage to wood in service in both residential and industrial applications, leading to estimated $1B in losses annually. Wood decay fungi have also been exploited for use in industrial processes ranging from...

Naturally-durable wood species are offered as an alternative to chemically-treated wood for decking and siding. Restrictions on imports due to non-sustainable forest practices often limit the availability of tropical hardwoods, many of which are considered durable. The Forest Products Laboratory is evaluating native naturally-durable woods for use in covered bridge repair and rehabilitation in conjunction with the Federal Highway Administration to provide native alternatives to tropical hardwoods. Six wood species that are considered either invasive or underutilized were selected for both...

Cross-Laminated Timber (CLT) garners international interest with increasingly taller wood structures built of robust, rigid panels. For seismic resilience of multistory platform construction, this study prototypes a CLT rocking wall system with an elliptical boundary profile. Curvilinear cuts to the load-bearing edges of a rectangular CLT panel produce smoother lateral response to earthquakes, with gravity-driven passive re-centering ability and reduced crushing damage at wall corners. Stiffness and ductility of the rocking wall can be tuned by proportioning the ellipse profile. Connections...

Kraft lignin was catalytic graphitized by iron at 1000 C in argon, hydrogen, CO2, methane, and natural gas atmospheres, respectively. The effect of atmospheric agent types on product distribution (gas, liquid, and solid carbon yields) was analyzed. The solid products were characterized by scanning electron microscopy, Raman, high-resolution transmission electron microscopy, and X-ray diffraction. Experimental results have shown that the degree of graphitization of Kraft lignin depends not only on the highest temperature, but also the type of ambient gas phase during heat treatment. Methane...