Treesearch

The 21st International Nondestructive Testing and Evaluation of Wood Symposium was hosted by the Forest Research Institute Baden-Württemberg (FVA) in Freiburg, Baden-Württemberg, Germany, September 24–27, 2019. This symposium was a forum for those involved in nondestructive testing and evaluation (NDT/NDE) of wood and brought together many international researchers, NDT/NDE users, suppliers, representatives from various government agencies, and other groups to share research results, products, and technology for evaluating a wide range of wood products, including standing trees, logs,...

Developing advanced building materials with both excellent thermal insulating and optical properties to replace common glass (thermal conductivity of ∼1 W m−1 K−1) is highly desirable for energy-efficient applications. The recent development of transparent wood suggests a promising building material with many advantages, including high optical transmittance, tunable optical haze, and excellent thermal insulation. However, previous transparent wood materials generally have a high haze (typically greater than 40%), which is a major obstacle for their practical application in the replacement...

Housing prices have generally performed better than economies in most countries in the UNECE region. Economic projections and house-price analysis can provide insights into the housing construction, sales and remodelling markets and subsequently into wood product demand. The Bank of International Settlements (BIS) reported that residential housing prices increased by 1.9% globally in 2018, year-onyear, and by 2.2% in the euro area, 2.0% in the US and 1.0% in the Russian Federation. Canadian house prices retreated, however, by 0.06%. According to BIS, real residential prices (adjusted for...

This paper numerically models the behavior of double-shear, single-bolted joints in wood-steel structures when subjected to very large deformations and compares results with test information. A three-dimensional finite-element model is developed of the main Douglas-fir wood member, steel side plates, bolt, washers, and nut. The model accounts for friction, bolt clearance, progressive damage in the wood, nonlinear and inelastic behavior in the steel bolts and side plates, and complete (linear and nonlinear) compressive constitutive response parallel to the grain in the wood. Hashin’s 3-D...

This study assessed the applicability of chitin nanocrystals employed in combination with an existing coating material intended for flexible packaging. The 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidized chitin nanocrystals (TOCNs) were applied 1) as an additive in a water-based acrylic resin (WBAR) that was then coated onto the surface of a biaxially oriented polypropylene (BOPP) film, and 2) as a neat layer in multilayered BOPP laminates bonded by a WBAR adhesive layer. The results indicated that the flow behavior and shear viscosity of the TOCN/WBAR system were dependent on TOCN...

Bruce R. Johnson worked at the USDA Forest Service Forest Products Laboratory (FPL) from 1969-1994. His research as a Forest Products Research Technologist covered many aspects of wood durability and preservation. He was considered an expert on marine exposure of treated wood and wood based materials. His reports on marine performance of treated wood are influential publications still commonly cited in the current literature. To those of us who worked with him at FPL, Bruce was a motivating and inspiring colleague who loved his marine research, especially in Key West, Florida. Bruce was...

Wood is one of the primary construction materials used in the United States. However, it is susceptible to decay over time, leading to its reduced service life. Development of targeted wood protection methods requires detailed understanding of microbial wood-decay mechanisms. Fungi are the most destructive microorganisms to attack wood and much research effort has been directed towards understanding their mechanisms of decay. The role of bacteria in wood-decay is less studied. The objective of this research was to compare bacterial communities colonizing pressure-treated and untreated...

Wood, a complex hierarchical material, continues to be widely used as a resource to meet humankind’s material needs, in addition to providing inspiration for the development of new biomimetic materials. However, for wood to meet its full potential, researchers must overcome the challenge of understanding its fundamental moisture-related properties across its many levels of hierarchy spanning from the molecular scale up to the bulk wood level. In this perspective, a review of recent research on wood moisture-induced swelling and shrinking is presented from the molecular level to the...

This study is part of a research project examining fire risk in cross aminated timber (CLT) bui dings. “De amination”, a major concern for CLT fire safety, can occur when the adhesive bondline fails in the pane before it chars which can lead to additional fuel for fire regrowth. Understanding the mechanical strength and stiffness of the adhesive bond under elevated temperature is one of the fundamenta steps towards better understanding delamination. In this study, the materia properties of wood and wood adhesive bonds are studied at various temperatures levels below the char temperature of...

Enzymatic conversion of cellulosic biomass into fermentable sugars such as glucose is a slow and catalytically ineûcient process, largely due to limited accessibility of cellulose. Cellulose crystallinity can be reduced to increase substrate accessibility toward cellulolytic enzymes by either swelling or dissolving biomass in chemicals such as concentrated acids (e.g., phosphoric acid or H3PO4, sulfuric acid or H2SO4) or ionic liquids. Phosphoric acid swollen cellulose (PASC) is one such highly digestible form of regenerated amorphous cellulose (RAC), enriched along with some cellulose-II...