Wood and Fiber Science (E-Journal)
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A Gate-To-Gate Life-Cycle Inventory of Solid Hardwood Flooring in the Eastern US
Get PDFEnvironmental impacts associated with building materials are under increasing scrutiny in the US. A gate-to-gate life-cycle inventory (LCI) of solid strip and solid plank hardwood flooring production was conducted in the eastern US for the reporting year 2006. Survey responses from hardwood flooring manufacturing facilities in this region accounted for nearly 28% of total US solid hardwood flooring production for that year. This study examined the materials, fuels, and energy required to produce solid hardwood flooring, coproducts, and the emissions to air, land, and water. SimaPro software was used to quantify the environmental impacts associated with the reported materials use and emissions. Impact data were allocated on their mass contribution to all product and coproduct production of 1.0 m3 (oven-dry mass basis) of solid hardwood flooring. Carbon flow and transportation data are provided in addition to the LCI data. Results of this study are useful for creating a cradle-to-gate inventory when linked to LCIs for the hardwood forest resource and the production of solid hardwood lumber in the same region
Introduction to Special Issue: Extending the Findings on the Environmental Performance of Wood Building Materials
Get PDFWood I-Joist Model Sensitivity to Oriented Strandboard Web Mechanical Properties
Get PDFResearch on wood I-joist design has often used laboratory testing, but simulation using the finite element method (FEM) offers advantages, including the possibility to separately study different joist components. The objective of this project was to perform a sensitivity analysis using FEM to determine which oriented strandboard (OSB) properties have higher impact on I-joist shear strain and deflection. OSB mechanical properties were changed from 50 to 200% of the reference value to determine their impact on web shear strain and I-joist deflection. The model was primarily sensitive to in-plane web shear stiffness, which changed I-joist deflection up to 23%. The model was also sensitive to the web tensile modulus of elasticity parallel and perpendicular to joist length and, to a lesser extent, to web shear stiffness. These properties changed I-joist deflection up to 2 and 1%, respectively. These findings will be used to plan future work to experimentally determine sensitive OSB web properties required to develop a finite element model of the mechanical behavior of wood I-joists
Enhancing the Fuel Value of Wood Pellets with the Addition of Lignin
Get PDFBecause of the increased cost of petroleum-based energy production, there is renewed interest in the use of wood for energy. In particular, residential heating using wood pellets has experienced a large increase during the last decade. Manufacturers of wood pellets are interested in producing high-quality, high fuel-value pellets. In this study, lignin was explored as an additive to wood to enhance pellet fuel value. Two types of lignin were examined in the production of wood pellets, Kraft black liquor and Indulin AT (IAT). Lignin was added to a softwood furnish and pellets were prepared on a commercial California Pellet Mill. The pellets were analyzed for fuel value, moisture content, and quality. Those prepared with IAT produced better quality pellets and had a higher fuel value than with Kraft black liquor. The Kraft black liquor pellets were soft and spongy and easily fell apart. A cost analysis indicates that lignin preparation will have a major impact on the feasibility of adding lignin to wood pellets to enhance fuel value
Characterizing the Importance of Carbon Stored in Wood Products
Get PDFCarbon emissions and stores are increasingly important as solutions are sought to address climate change. Focusing on some forest-related carbon pools but omitting product carbon frequently results in invalid conclusions. This study examined carbon emissions and stores in the life cycle of wood products in comparison with alternative materials. Emissions were established from a sustainably managed, carbon-neutral forest through processing to wood product use in residential structures and their eventual disposal. A life-cycle inventory was developed to establish the quantity of emissions from each stage of processing, and a life-cycle assessment of a representative residential building was made of its impact on global warming potential. The carbon stored in wood products as an offset to emissions was shown to be significant. Comparison of various building materials—wood, steel, and concrete—showed that wood was more environmentally friendly because of reduced carbon emissions because of fossil fuel combustion, carbon stored in products, permanent avoidance of emissions from fossil fuel-intensive products, and use of a sustainable and renewable resource
From Hydrophilicity to Hydrophobicity: A Critical Review: Part I. Wettability and Surface Behavior
Get PDFSurface properties of wood are important for both wettability and hydrophobic modification. Glueability of wood is related to wettability, while durability and decay resistance are affected by physical and chemical components. This review (Part I) discusses hydrophilic characteristics of surfaces. Surface theories, calculation methods for surface tension, topography, contamination, and aging are reviewed. It was found that surface tension data were often disparate; a standardized procedure for contact angle measurement would permit reproducible measurements and comparable data for surface characterization. Surface tension of wood can be estimated using Zisman's critical surface tension, geometric-mean, harmonic-mean, and acid-base approaches. To date, however, no procedures have been developed for determining absolute values of surface tension. Few controversies exist in the literature regarding effects of surface topographic characteristics on surface tension. However, there are disputes regarding mechanisms of surface contamination and aging. Further research on surface tension of wood is warranted. Hydrophobic modifications and superhydrophobic wood are discussed in Part II
Mechanical Properties of Genetically Engineered Young Aspen with Modified Lignin Content and/or Structure
Get PDFReducing lignin content is a target for processes such as papermaking because lignin removal requires a tremendous amount of energy and chemicals. Recent advances in tree genetics permit modification of lignin content and structure. The consequences of lignin modifications on many wood properties are not known. The purpose of this study was to establish the effect of genetic modification of lignin on selected wood mechanical properties. In this study, genetically modified young quaking aspen trees with reduced lignin content and/or increased syringyl to guaiacyl (S/G) ratio were investigated and compared with the wild type. The modulus of elasticity in three-point bending and the compression strength parallel to the grain were measured using modified micromechanical tests. The results indicate that the genetic modification used in this study had a negative effect on these mechanical properties. The transgenic trees with reduced lignin content showed a severe reduction in modulus of elasticity and compression strength parallel to the grain, whereas the transgenic trees with increased S/G ratio had only a slight decrease in these properties compared with the wild type. The simultaneous modification of lignin content and S/G ratio shows inconsistent results and needs further investigation
Life-Cycle Inventory of Formaldehyde-Based Resins Used in Wood Composites in Terms of Resources, Emissions, Energy and Carbon
Get PDFLife-cycle inventory (LCI) data are needed to scientifically document the environmental performance of formaldehyde-based resins used in the manufacture of wood composite products. The resin data are needed by others to conduct LCI studies of wood composites when providing performance data for applications as governed by the many green building standards, purchasing guidelines, and energy and climate change-related polices. This study develops LCI data for urea—formaldehyde, melamine-urea-formaldehyde, phenol-formaldehyde, and phenol-resorcinol-formaldehyde resins as produced in the US for 2005. Data are given for both on-site (resin manufacture) and cradle-to-gate (from the resin upstream to in-ground resources), which include those resources to produce and deliver input chemicals, fuels, water, and electricity. The LCI data are given per 1.0 kg of neat (liquid) resin at their industry use solids content in terms of raw materials use and emissions to air, water, and land; data are also presented on embodied energy, carbon flow, store, and footprint
Cradle-to-Gate Life-Cycle Inventory of us Wood Products Production: Corrim Phase I and Phase II Products
Get PDFThis article documents cradle-to-gate life-cycle inventories for softwood lumber, hardwood lumber, and solid-strip hardwood flooring manufacturing from the Inland Northwest and the Northeast-North Central regions of the US. Environmental impacts were measured based on emissions to air and water, solid waste, energy consumption, and resource use. The manufacturing stage consumed the greatest amount of energy representing 90 - 92% of the total. Total energy consumption for softwood lumber manufacturing was about one-half of that required for hardwood lumber and hardwood flooring. The use of wood biomass as the primary energy source for manufacturing greatly reduced the environmental burdens by offsetting the demand for fossil fuels. Transportation impacts contributed approximately 3%, and forestry and harvesting operations accounted for 3 - 7%. Management and harvesting of softwoods in the Northeast-North Central regions required a greater amount of energy attributable to higher-intensity management scenarios
Use of Artificial Neural Networks as a Predictive Method to Determine Moisture Resistance of Particle and Fiber Boards Under Cyclic Testing Conditions (UNE-EN 321)
Get PDFDetermining internal bond strength and thickness swelling after cyclic aging tests in humid conditions is essential to assess moisture resistance of particle and fiber boards. However, because operating procedures for these types of tests take at least 3 wk, their use in daily finished product control is impractical. To solve this problem, an artificial neural network was used as a predictive method to determine these values from the board properties of thickness, density, and moisture content in conjunction with thickness swelling and internal bond strength values obtained before the aging cycle. Using 113 boards, an artificial neural network was designed consisting of two separate feedforward multilayer perceptrons applying the hyperbolic tangent as the transfer function. Training was conducted through supervised learning after the input data had been normalized. In the testing group, the network attained a determination coefficient of 0.94 for internal bond strength and 0.92 for thickness swelling