Wood and Fiber Science

Characterization of bondlines in cross-laminated timber made with preservative-treated lumber

2024-07-09T19:09:31-07:00

The number of mass timber construction projects is rapidly increasing in North America but this technology encounters durability issues where termites are present. One method for minimizing this risk is to incorporate termiticidal treatments into mass timber elements. This study examined the impact of pre and post layup treatment of cross laminated timber (CLT) on bond line integrity. Douglas-fir 2 × 6-inch lumber or CLT panel sections were pressure treated with 1) borates or 2) (PTIP), or 3) dip treated with a mixture of propiconazole, tebuconazole and imidacloprid + borate (PTIB). CLT panels were manufactured using melamine formaldehyde (MF) or polyurethane (PUR) resins. The impact of preservative treatment on bondline integrity was tested by delamination and block shear tests. Adhesive penetration was also measured using fluorescence microscopy and surface wettability was measured using a contact angle analyzer. Planing treated lumber prior to use in CLT panel assembly reduced actives by 57—94% compared to unplaned lumber containing the same treatment. Panels made with borate treated lumber were more easily delaminated than panels composed of PTIP treated wood. Microscopic evaluation of CLT bondlines showed greater resin penetration in panels made with PTIP-treated wood; however, penetration was highly variable across specimens. Borate-containing treatments increased surface wettability which may have contributed to reduced treated panel performance. The results help define the challenges associated with incorporating biocidal treatments into panels and identify some mechanisms by which they reduce performance.

WOOD MOISTURE CONTENT DETERMINATION BY HANDHELD NEAR-INFRARED REFLECTANCE SPECTROMETER

2024-07-14T12:34:59-07:00

Rapid, accurate determination of wood moisture content is of paramount importance for the wood industry, infrastructure maintenance, studies of plant physiology, and forest management. Near-infrared reflectance spectroscopy (NIRS) is a widely used non-destructive technique for analyzing properties of materials, including moisture content. Small, portable, handheld NIR spectrometers represent an emerging technology with strong potential for rapidly, affordably estimating materials properties. Here, we used a SCiO^TM miniature handheld NIR spectrometer and a partial least squares (PLS) regression model to predict wood moisture content. The model was developed using spectra (740-1070 nm) collected from increment borer wood samples from 41 representative softwood and hardwood trees, calibrated against gravimetric wood moisture content determined by oven-drying. The calibration and prediction datasets contained 2/3^rd and 1/3^rd of all data, respectively. We explored effects of different spectral preprocessing algorithms (i.e., first and second-order derivatives and standard normal variate transformations) on model performance. First-order derivative spectra with five latent variables yielded the most robust model (R²: 0.72, RMSE_P: 0.32, ratio of performance to deviation: 2.2). Broadly, we demonstrated that relatively low-cost miniature handheld NIR spectrometers such as the SCiO^TM can rapidly estimate percent moisture content in wood of various species.

GRAIN ANGLE EFFECTS ON ACOUSTIC EMISSION CHARACTERISTICS OF SOUTHERN YELLOW PINE COLUMNS UNDER COMPRESSION

2024-08-09T09:46:47-07:00

This study investigated the influence of wood grain angle (0, 10, 20, 30, 45, 60, 75, and 90 degrees) on acoustic emission (AE) characteristics of southern yellow pine columns subjected to compressive loading. Four AE parameters considered were counts, cumulative counts, count rate, and amplitude. The main conclusion was that AE cumulative counts versus time curves can be characterized with three distinct stages in terms of AE count rates: initiation, growth, and acceleration. The initiation stage had a constant mean count rate of 0.33 counts/s compared to the growth stage mean count rate of 19.10 counts/s, while the acceleration stage had a mean count rate of 608.40 counts/s. Within each stage, count rates increased as grain angle increased from 0 to 30 degrees, then dropped as grain angle further increased to 90 degrees. Maximum AE counts and total cumulative AE counts all increased as grain angle increased from 0 to 30 degrees and decreased as grain angle further increased to 90 degrees. Higher AE amplitudes were observed in the yield and failing stages of tested wood columns according to their stress-strain curves plotted together with their corresponding amplitude-time curves. Maximum amplitude increased as grain angle increased from 0 to 20 degrees, then had a decreasing trend as grain angle increased to 45 degrees, followed by an increasing trend as grain angle increased to 75 degrees. These differences in AE characteristics suggested that AE “signatures” in terms of AE signals do exist for timber materials when subjected to compressive loading.

Sustainability Reporting and Performance: A Comparative Study of Leading Paper and Paper-based Packaging Companies

2024-08-22T11:16:35-07:00

This research presents a comparative analysis of sustainability performance of four prominent companies within the paper and paper-based packaging industry. Utilizing established sustainability indicators encompassing environmental, social, and economic dimensions, the study evaluated company performance based on publicly available data from their sustainability reports and disclosures. The findings revealed a diverse landscape of sustainability commitments and achievements, highlighting both shared industry-wide trends and company-specific approaches to sustainability management. All four companies demonstrated a strong commitment to waste management and circular economy principles, while also exhibiting varying degrees of progress in areas such as renewable energy adoption, carbon emissions reductions, employee well-being, and social responsibility initiatives. The analysis further identified opportunities for improvement and highlighted the need for greater transparency, data disclosure, and industry collaboration to enhance overall sustainability performance and contribute to a more sustainable future for the paper and paper-based packaging sector. By examining the similarities and differences in the sustainability journeys of these four companies, this study provides valuable insights for industry stakeholders, policymakers, and researchers interested in promoting sustainable development within the paper and packaging industry and beyond.

DEFLECTION PERFORMANCE OF MEDIUM DENSITY FIBERBOARD AND PARTICLEBOARD SHELVES JOINED ABS, PLA, AND WOOD-PLA FILAMENT PINS

2023-11-09T14:12:17-08:00

This study determined the deflection performance of wooden shelves force by using different material types. In addition, the pins used as fasteners of the shelves are made of ABS, PLA and WOOD-PLA filament material. The independent variables consisted of material type, pins fila-ment material, and filament fill, and the dependent variable was determined as deflection value. Medium density fiberboard (MDF) and particleboard (PB), both melamine faced, were used as two different material types. The study was based on the BS EN 16122 (2012) standard. However, the TS EN 9215 (2005) standard was followed to reveal the deformations that occur in the shelves after increasing loads. The factors affecting deflection value and the interaction between them were investigated by multivariate analysis of variance. The results showed that the material type, filament fill and filament material type were significant. The adequacy of models was evaluated by the R-square (R²) and Adjusted R-square (Adj-R2) values. The results for these val-ues were 96.1 % and 94.2 %, respectively.