Treesearch

It has been common practice to assume that a 2-parameter Weibull probability distribution is suitable for modeling lumber strength properties. Previous work has demonstrated theoreti-cally 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 2-parameter Weibull. Instead, the tails of the MOR distribution are thinned via pseudo-truncation. Simulations have established that fitting 2-parameter Weibulls to pseudo-truncated data via either full or cen-sored data methods can yield...

Sealants are critical components of building construction. They must prevent air and water leaks in the building envelope to prevent moisture damage and maintain comfort and energy efficiency. Simultaneously, they must absorb relative motion between the building components as materials expand and contract due to changes in environmental conditions. Repairing failed sealant is an expensive, labor-intensive operation. Common understanding is that sealants fail under tension as they age and stiffen. Experiments at the Forest Products Laboratory using outdoor exposure with movement, laboratory...

A novel process is developed for high-volume production of low-cost graphene materials from any solid carbon resources, especially biomass sources. Few-layer graphene materials from solid carbon resources are produced through a molecular cracking and welding (MCW) method. The MCW technique is a single step process with two stages, i.e., graphene-encapsulated core–shell nanoparticles are first formed by catalytic thermal treatment of solid carbon materials. Then in the second stage these core–shell structures are opened by ‘cracking molecules’, and the cracked graphene shells are self-welded...

A type of blocked experiment has the potential of being poorly designed and analyzed. Several papers by Verrill and co-workers referred to such an experiment as a “predictor sort” experiment. It has also been referred to in other papers and textbooks as “artificial pairing” and “matched pair” or “matched subjects” design. The associated design process is also sometimes described as “forming blocks via a concomitant variable.” In a wood research context, the response in such an experiment might be lumber strength after a treatment, and the predictor used to form blocks would be some...

This report presents current and historical annual data on the production, trade, consumption, and prices of timber products in the United States. The report also focuses on national statistics but includes some data for individual states and regions and for Canada. The data were collected from industry trade associations and government agencies. They are intended for use by forest land managers, forest industries, trade associations, forestry schools, renewable resource organizations, individuals in the major timber producing and consuming countries of the world, and the general public. A...

Novel hybrid panel composites based on wood, fungal mycelium, and cellulose nanofibrils (CNF) were developed and investigated in the present study. In one set of experiments, mycelium was grown on softwood particles to produce mycelium-modified wood which was then hybridized with various levels of CNF as binder. The other set of experiments were conducted on unmodified wood particles mixed with CNF and pure mycelium tissue. It was found that the composites made of mycelium-modified wood and CNF resulted in enhanced physical and mechanical properties compared to the ones made by physically...

Bio-based flours derived from distiller s dried grains with solubles (DDGS), Osage orange seed meal (OOSM), or defatted commercial soybean meal flour-Prolia (PRO) were employed as adhesives with Eastern redcedar (Juniperus virginiana L.) wood (ERC) to fabricate composite wood panels (CWPs). OOSM and DDGS were defatted, milled, and screened prior to use. PRO was employed as provided. DDGS, OOSM, or PRO flour were mixed dry with ERC wood to make CWPs using the following conditions: molding temperature of 185 °C, ERC particle sizes of ≤75µm to 1700 µm, pressure of 5.6 MPa, and employed in...

Poplar wood was rapidly fractionated via a flow-through reaction using aqueous solutions of an acid hydrotrope (AH), p-toluenesulfonic acid (p-TsOH), at temperatures below 98 °C. 13C−1H two-dimensional nuclear magnetic resonance (NMR) spectroscopic analyses demon-strated that the AH-solubilized lignins (AHLs) from a range of fractionation conditions with yields up to approximately 80% had a very high content of β-aryl-ether linkages compared to milled wood lignin (MWL) with a low enough condensation to facilitate subsequent reductive catalytic depolymerization resulting in a lignin monomer...

Three commercial xylanases and an endoglucanase preparation were compared in the enzymatic pretreatment of bleached eucalyptus pulp for producing cellulose nanofibrils (CNFs) through subsequent microfluidization. Commercially provided xylanases X10A and X10B hydrolyzed more xylan than the X11 xylanase. Moreover, the average degrees of polymerization (DP) of the fibers after treatments using xylanases X10A and X10B (DP * 1000) were lower than for the fibers following treatment using xylanase X11 (DP * 1100). Based on protein molecular weight, the commercial xylanases X10A and X10B are both...

Nationwide, bridges are deteriorating at a rate faster than they can be rehabilitated and maintained. This has resulted in a search for new methods to rehabilitate, repair, manage, and construct bridges. As a result, structural health monitoring and smart structure concepts have emerged to help improve bridge management. In the case of timber bridges, however, a limited amount of research as been conducted on long-term structural health monitoring solutions, and this is especially true in regards to historic covered timber bridges. To date, evaluation efforts of timber bridges have focused...