Treesearch

To maximize utilization of our forest resources, detailed knowledge of wood property variation and the impacts this has on end-product performance is required at multiple scales (within and among trees, regionally). As many wood properties are difficult and time-consuming to measure our knowledge regarding their variation is often inadequate as is our understanding of their responses to genetic and silvicultural manipulation. The emergence of many non-destructive evaluation (NDE) methodologies offers the potential to greatly enhance our understanding of the forest resource; however, it is...

Full sets of elastic constants of green Chinese larch (Larix principis-rupprechtii Mayr) with 95% moisture content at four different cross-section sampling positions (from pith to sapwood) were determined in this work using three-point bending and compression tests. Variations in the material constants of green Chinese larch from pith to sapwood were investigated and analyzed. The results showed that the sensitivity of each elastic constant to the sampling position was different, and the coefficient of variation ranged from 4.3% to 48.7%. The Poisson’s ratios νRT measured at four different...

In this study, the economic feasibility of producing ethanol from gasifcation followed by syngas fermentation via commercially available technologies was theoretically evaluated using a set of selected livestock and agricultural and forest residuals ranging from low valued feedstocks (i.e., wood, wheat straw, wheat straws blended with dewatered swine manure, and corn stover) to high valued oilseed rape meal. A preliminary cost analysis of an integrated commercial system was made for two cases, a regional scale 50 million gallon (189,271 m3) per year facility (MGY) and a co-op scale 1–2 MGY...

Climate change, environmental degradation, and limited resources are motivations for sustainable forest management. Forests, the most abundant renewable resource on earth, used to make a wide variety of forest-based products for human consumption. To provide a scientifc measure of a product’s sustainability and environmental performance, the life cycle assessment (LCA) method is used. This article provides a comprehensive review of environmental performances of forest-based products including traditional building products, emerging (mass-timber) building products and nanomaterials using...

Fundamental thermal properties of fresh leaves that are essential to CFD modeling of leaf pyrolysis and flammability are related to leaf composition and moisture content. The focus of this paper is on measuring and providing functional relationships for the heat of combustion, specific heat capacity, and heat of moisture desorption for fresh leaves as they vary with moisture content and composition. With the leaves typically being within a fraction of a millimeter thick and having internal structures of petiole, veins, and blades filled with active living moisture and organic compositions...

Ilopango volcano (El Salvador) erupted violently during the Maya Classic Period (250e900 CE) in a densely-populated and intensively-cultivated region of the southern Maya realm, causing regional abandonment of an area covering more than 20,000 km2. However, neither the regional nor global impacts of the Tierra Blanca Joven (TBJ) eruption in Mesoamerica have been well appraised due to limitations in available volcanological, chronological, and archaeological observations. Here we present new evidence of the age, magnitude and sulfur release of the TBJ eruption, establishing it as one of the...

This study focuses on understanding the effect of cellulose nanocrystals (CNCs) on glass fber/epoxy interfacial interactions. The glass fbers (GF) were coated with solutions containing cellulose nanomaterial. The parameters that were investigated were the CNC surface chemistry, concentration, and dispersing medium, i.e., aqueous solution only versus emulsions. To determine the effect of the CNC coatings on the interfacial adhesion, specimens of a single GF in an epoxy matrix were prepared for GF coating by varying the coating formulations. The interfacial shear stress (IFSS) was determined...

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...