Treesearch

In this paper, the behavior of an acoustic wave within an idealized wood specimen are compared and contrasted to the acoustic behavior observed in clear wood and lumber using signal processing and analysis. Published information on the physical and mechanical properties of clear, defect-free wood is used to derive a model of acoustic wave behavior. The model closely matches results observed from defect-free wood. Wave behavior is also examined in a series of wood specimens containing strength reducing defects such as knots and slope of grain. Differences between the idealized model results...

Two fluorescence-tagged carbohydrate-binding modules (CBMs), which specifically bind to crystalline (CBM2a-RRedX) and paracrystalline (CBM17-FITC) cellulose, were used to differentiate the supramolecular cellulose structures in bleached softwood Kraft fibers during enzyme-mediated hydrolysis. Differences in CBM adsorption were elucidated using confocal laser scanning microscopy (CLSM), and the structural changes occurring during enzymemediated deconstruction were quantified via the relative fluorescence intensities of the respective probes. It was apparent that a high degree of order...

Hygrothermal models are commonly used for prediction and evaluation of wall assembly moisture performance. Drying and redistribution of moisture are important to consider because they mitigate the effect of water intrusion during construction and throughout the service life of the building. In this study we compare simulations with measurements for two out of eight different residential wood-frame wall assemblies, in two orientations, with different kinds of insulation outboard of the oriented strand board (OSB) sheathing, in the cold climate of Madison, WI. Over two years we collected...

The use of mass timber structural products (such as glulam and cross-laminated timber) in commercial buildings is increasing in prevalence around the world. Whereas moisture management during the construction process is important for all building types, it is especially important for buildings with wood structural members. The exposure of mass timber products to the environment during construction can result in wetting of the wood, and mass timber products may take longer to dry than lightweight wood-frame construction. To better understand the moisture conditions to which mass timber...

A “green” oxyalkylation protocol employing ethylene carbonate (EC), polyethylene glycol 400 (PEG400), and water was developed to convert an industry byproduct, kraft lignin (KL), into biopolyols for the production of rigid polyurethane (RPU) foams. EC served as an oxyalkylation reagent for the derivatization of KL’s hydroxyl (OH) groups. PEG400 and water served as a co-solvent and a reactive additive, respectively, to tailor two properties of the KL-derived biopolyols, those being viscosity and OH number. For the oxyalkylated-KL (OKL), as characterized by 31P-nuclear magnetic resonance...

With increasing global water temperatures and nutrient runoff in recent decades, the blooming season of algae lasts longer, resulting in toxin concentrations that exceed safe limits for human consumption and for recreational use. From the different toxins, microcystin-LR has been reported as the main cyanotoxin related to liver cancer, and consequently its abundance in water is constantly monitored. In this work, we report a methodology for decorating cellulose nanofbrils with β-cyclodextrin or with poly(β-cyclodextrin) which were tested for the recovery of microcystin from synthetic...

Biodeterioration of building materials due to poor hygrothermal conditions is a major concern for the sustainability of buildings and the health and safety of occupants. The risks of biodeterioration are accentuated in high-efficiency buildings, requiring further design considerations. Researchers across the world have tried to characterize this issue through a combination of field experience, modeling, and controlled laboratory investigations. However, integration of these research outputs in building enclosure design analysis is an unfinished agenda, partly due to the lack of coordination...

Nanocellulose is conventionally produced from woody biomass including wood, crops and forest/agricultural residues, by top-down methods. Due to biomass recalcitrance, pretreatment, with a subsequent bleaching process, is mandatory to break down the resistance of the composite for nanocellulose extraction. In the present study, gamma-valerolactone (GVL) pulping without further bleaching/purification was used for producing cellulose nanomaterials from wood. GVL pulp and bleached kraft pulp from Aspen were comparatively studied as starting materials for (2,2,6,6-tetramethylpiperidin-1-yl)oxida...

It has been common practice to assume that a two-parameter Weibull probability distribution is suitable for modeling lumber strength properties. Verrill and others (papers published in 2012, 2013, 2014, and 2015) 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 two-parameter Weibull. Instead the tails of the MOR distribution are thinned via “pseudo-truncation.” Verrill and others (papers published in 2013 and 2014) performed simulations that...

The development of composite mass timber products in the late 20th century continues to generate new developments in the design and production of multi-layer wood products in a wide variety of orientations and for a wide variety of uses. In the US Congress’ Agricultural Act of 2014, provisions were specified in Section 7310 to establish a series of priorities for research into the needs of the forestry sector. Specifically, collaborative research efforts into the increased use of CLT in support of the expansion of this portion of the forest products industry were addressed. Cross laminated...