Treesearch

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...

The development of new and improved wood adhesives is hindered by an incomplete mechanistic understanding of what makes a wood–adhesive bond able to withstand changes in moisture levels. Although common methods are established to test and report the bulk-level properties of bond lines, such as bond-line shear strength and wood failure analysis, the development of experimental tools to study wood–adhesive bond lines and the effects of moisture at the nanometer to millimeter length scales remains an active area of research. Here we introduce and briefly review four recently developed tools...

Cellulose nanocrystal (CNCs)-reinforced poly(lactic acid) (PLA) nanocomposites were prepared using twin screw extrusion followed by injection molding. Masterbatch approach was used to achieve more efficient dispersion of CNCs in PLA matrix. Modified CNCs (b-CNCs) were prepared using benzoic acid as a nontoxic material through a green esterification method in a solvent-free technique. Transmission electron microscopy images did not exhibit significant differences in the structure of b-CNCs as compared with unmodified CNCs. However, a reduction of 6.6–15.5% in the aspect ratio of b-CNCs was...

This paper evaluates the potential of using 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized cellulose nanoparticles (T-CNPs) as additives to tune the rheology of water-based acrylic resin (AR) coatings for flexible packaging applications. Three T-CNPs of T-CNF, T-MCC, and T-CNC were prepared from three starting cellulosic materials: cellulose nanofibers (CNF), microcrystalline cellulose (MCC), and cellulose nanocrystals (CNC), respectively. Their sizes ranged from 20 nm to 20 lmin diameter, and 234 nm to over 500 nm in length. The oxidation imparted carboxyl groups on the surfaces...