Treesearch

Low-value residues from forest restoration activities in the western United States intended to mitigate effects from wildfire, climate change, and pests and disease need a sustainable market to improve the economic viability of treatment. Converting biomass into bioenergy is a potential solution. Life-cycle assessment (LCA) as a sustainable metric tool can assess the impact of new bioenergy systems. Using the internationally accepted LCA method, this study evaluated the syngas electricity produced via a distributed-scale biomass pyrolysis system called the Tucker Renewable Natural Gas...

Conifers possess a suite of physiochemical defenses that protect their subcortical tissues from bark beetle -fungal complexes. These defenses include rapid induction of terpenoids and phenolics at the site of attack. Studies of the distribution, induction, and bioactivity of conifer terpenoids have focused heavily on monoterpenes. We assessed induction of diterpene acids in white spruce (Picea glauca) and red pine (Pinus resinosa) to fungal associates of two bark beetles, and the responses of four spruce beetle (Dendroctonus rufipennis)—associated fungi to three diterpene acids. Constitutiv...

Electrical impedance spectra of wood taken at macroscopic scales below the fibre saturation point have led to inferences that the mechanism of charge conduction involves a percolation phenomenon. The pathways responsible for charge conduction would necessarily be influenced by wood structure at a variety of sub-macroscopic scales – at a mesoscale – but these questions have not yet been addressed. The goal of this work is to explore if mesoscale anatomical features in wood affect impedance spectra. Small (0.5mmdiameter) needles were used as electrodes and were configured such that the line...

Long-term moisture performance is a critical consideration for design and construction of building envelopes in energy-efficient buildings, yet field measurements of moisture characteristics for highly insulated wood-frame walls in mixed-humid climates are lacking. Temperature, relative humidity, and moisture content of wood framing and oriented strand board (OSB) structural panel sheathing were measured over a period from mid-November 2011 through March 2013 in both north- and south-facing orientations in test structures near Washington, DC, USA. Wall configurations varied in exterior...

The percolation model developed by Zelinka et al. was based upon macroscale measurements of the electrical conductivity and implicitly treats the wood material as homogenous. The transport mechanism proposed by Jakes et al. depends upon a moisture induced glass transition occurring in the hemicelluloses. This theory suggests that there are likely differences in the threshold moisture content for moisture transport between different regions in the cell wall. For instance, the secondary cell wall contains cellulose microfibrils, amorphous cellulose, hemicelluloses, and lignin, where hemicellu...

Future use of woody biomass to produce electric power in the U.S. North can have an important influence on timber production, carbon storage in forests, and net carbon emissions from producing electric power. The Northern Forest Futures Project (NFFP) has provided regional- and state-level projections of standing forest biomass, land-use change, and timber harvest, which all influence forest contributions to global carbon cycles. This study supports the NFFP study of global carbon cycles by estimating potential local woody biomass supply under alternate procurement regimes and associated...

X-ray densitometry is a technique often used in tree growth and wood quality studies to incrementally measure density (specific gravity) along a radial strip of wood. Protocols for this technique vary between laboratories because of differences in species, equipment, tree age, and other factors. Here, the application of X-ray densitometry is discussed in terms of a case study specific to the southern pines, whereby loblolly (Pinus taeda L), longleaf (Pinus palustris Mill.), and slash (Pinus elliottii Engelm.) pine wood cores were analyzed using an automated system. Objectives of this study...

This paper reports the results of a search to discover the most cost effective and robust method of detecting Reticulitermes flavipes infestations in structural members of remote bridges, homes and other wooden structures and transmitting these results to internet cloud storage thus obviating routine travel to these structures for periodic visual inspections. Duplicate stainless steel tanks were constructed for housing R. flavipes colonies and commodity size dimension lumber members. Overall, results indicated that the simplest and cheapest independent variables to measure and send were:...

Epoxy printed circuit boards are used in a variety of electronics applications as rigid, thermally stable substrates. Due to the propensity of components on the boards, such as batteries and interconnects, to fail and ignite the epoxy, flame retardant additives are required to minimize fire risk. Currently, industry uses brominated flame retardants, such as TBBPA, to meet regulatory requirements1. However, recently, a number of environmental and human health issues have been raised about brominated compounds, so there is a desire to develop alternative flame retardant chemistries

Except for the substitution of soy flour in phenolic resins (Frihart et al. 2013) and the use of soy flour at high pHs (Lambuth 2003), the literature on soy protein properties for adhesives has mainly focused on soy protein isolate and specific protein fractions (Sun 2005b). The assumption is that proteins are the main portion of soy flour giving bond strength and the carbohydrate portion serves as an inert diluent. Given our observed inability to greatly alter soy flour adhesion using chaotropic agents, salts, surfactants, or co-solvents (Frihart and Lorenz 2013), which is in contrast to...