Volume 20 Issue 2

Glued wood finger-jointed panels are widely employed due to their efficient use of wood resources and the enhancement of product quality. To address defects in the quality inspection of these panels, a set of ultrasonic glued laminated wood finger-joined board inspection systems was designed using Barker Code pulse excitation. This was achieved by adopting air-coupled ultrasonic technology and incorporating phase coding technology. Relevant validation experimental research was carried out on the performance of the system. The results show that the system covered two key components, namely hardware and software, which enabled its ultrasonic transducer to realise the functions of rapid scanning of the internal and external qualities of the board and automatic C-scan inspection imaging to identify defects in the specimen without contacting the glued wood finger-joined board specimen. The validation test confirmed that the inspection system achieved good accuracy and reliability. It was concluded that this approach has potential to improve the quality inspection technology of glued laminated direct lumber and to promote the development of wood processing industry.

Lignin can be used as a natural anticancer drug because of its potential biological activity and low cytotoxicity. This research focuses on oligomeric dehydrogenation polymers (DHPs) of lignin. The lignin precursor coniferin was used to yield Zulaufverfahren dehydrogenation polymers (ZL-DHPs) and Zutropfverfahren dehydropolymers (ZT-DHPs) catalyzed by mixed enzymes. The ¹³C-NMR determination showed that the DHPs obtained were similar to natural lignin, and ZL-DHP had a slightly higher β-5 content than ZT-DHP. ZL-DHPs and ZT-DHPs were subjected to organic solvent extraction with different polarities to obtain eight fractions, i.e., ZL-1-ZL-4 and ZT-1-ZT-4. The antitumor activity showed ZL-2 (IC₅₀ 181.99 μg/mL) and ZT-2 (IC₅₀ 246.76 μg/mL) had significant inhibitory effects. Fractions ZL-2 and ZT-2 were purified through column chromatography using gradient-polarity binary eluent, and 12 purified compounds were obtained, i.e., L1–L6 and T1–T6. The results showed L2 (IC₅₀ 33.99 μg/mL) and T1 (IC₅₀ 42.08 μg/mL) had relatively high biological activity, respectively. Their structure was characterized using high-resolution mass spectrometry and ¹³C-NMR, indicating that L2 is a dimer with β-5 linkage (β-5, γ-CH₃, and γ’-CH₂OH), and T1 is also a dimer with β-5 linkage but different substituents (β-5, γ-CHO, and γ’-COOH).

Glued-laminated timber (glulam) is a structural wood-based composite widely used in construction. One of the constraints to its production is the requirement that lamellae must have the same moisture content before bonding. This study analyzed the effect of joining lamellae having different moisture content levels on the bonding performance of glulam elements. Black spruce [Picea mariana (Mill.) B.S.P.] wood with different levels of moisture content (11%, 13%, and 15%) were bonded with two component polyurethane and placed in three different environments with different relative humidities. Block shear and delamination tests were performed according to ASTM D905-08 (2021) and EN 302-2 (2013), respectively, and the glue line profile was assessed with a micro-CT scanner. The results showed that the relative humidity had more influence on the results than the initial moisture of the wood. The results obtained for block shear and delamination tests respected the limits of the standard, but the adhesive profile of mixed moisture glulam presented some undesirable characteristics (thinner and irregular adhesive distribution). Micro-CT scan reconstructed images were found to be an interesting tool for this type of evaluation.

This study aimed to enhance rotational wood welding technology by developing a simplified prediction model for pull-out strength. The key findings can offer a robust evaluation framework to advance rotational wood welding and expand its applications in woodworking. For instance, (1) A comprehensive database of 689 previously published trials was curated to identify key factors: substrate diameter, effective welded length, and substrate density. (2) Comparative analysis of test outcomes and predictive models revealed consistent trends, suggesting that modeling techniques for self-tapping wood screws could be applied to rotational wood welding joints. (3) Univariate linear regression validated the primary factors, leading to a multivariate model for predicting withdrawal capacity. Theoretical predictions closely matched empirical data, highlighting the model’s industrial applicability.

To ensure the environmentally safe usage of copper amine-based wood preservatives in aquatic environments, it is necessary to minimize copper leaching from treated wood. In this study, alkaline copper quat (ACQ) was reformulated to enhance resistance to copper leaching by adjusting the proportions of copper, didecyldimethylammonium chloride (DDAC), and mono-ethanolamine (Mea) solvent. The copper proportion in the formulation was decreased 40% while maintaining the total retention of active ingredients through increasing DDAC. The molar ratio of Cu to Mea in the formulation was then adjusted from 1:4 to 1:2.75. This reformulation shortened the time to copper stabilization from 15 to 6 days, and reduced cumulative copper leaching by 75%, compared to a control formulation. These fixation properties were further improved with just a 30-min hot-air post-treatment at 100 °C. Wood treated with the reformulated ACQ exhibited comparable performance in biological efficacy against fungi and termites compared to wood treated with commercial ACQ.

5-Ethoxymethylfurfural (5-EMF) is a promising liquid fuel or fuel additive due to its high energy density and stability. The conversion of glucose to 5-EMF involves a three-step tandem reaction: isomerization, dehydration, and etherification. However, low catalytic efficiency in these steps has limited 5-EMF yields. To address this, a Fe/ZSM-5 bifunctional catalyst with both Brønsted and Lewis acid sites was developed and characterized using XRD, SEM, XPS, BET, Py-FTIR, and NH₃-TPD techniques. The catalyst’s performance in glucose conversion was systematically evaluated. Optimal conditions—20 wt% Fe loading, 180 °C reaction temperature, 10 h reaction time, and a catalyst-to-glucose mass ratio of 1:1—resulted in 97.1% glucose conversion and a 38.4% 5-EMF yield. Reaction kinetics followed a first-order model with an activation energy of 32.6 kJ/mol. The catalyst maintained over 94% glucose conversion after five cycles, demonstrating its stability. These findings underscore the potential of the Fe/ZSM-5 bifunctional catalyst for efficient glucose valorization to 5-EMF and provide key insights for process optimization.

This study integrates the Fuzzy Analytic Hierarchy Process (AHP) with the Failure Mode and Effects Analysis (FMEA) to enhance risk prioritisation in wood-based manufacturing. Traditional FMEA methods face challenges in handling subjective evaluations and complex environments. By incorporating fuzzy logic, this study refines the Risk Priority Number (RPN) calculation, enabling a more nuanced assessment of failure modes. Critical failure points, such as delays in order processing, production, and delivery, were identified, highlighting their impact on operational efficiency, customer satisfaction, and financial outcomes. Using the Pareto principle, it was revealed that addressing the top 20% of the identified risks could mitigate approximately 80% of the overall risk exposure. Proposed corrective measures, including enhanced employee training, streamlined workflows, and improved communication protocols, provide actionable strategies to optimise processes and ensure sustainability. Conducted within a Croatian wood-manufacturing company, this framework demonstrated its efficacy in refining risk assessments and supporting continuous improvement. The findings advance risk management methodologies and showcase the potential for broader applications in dynamic and complex industrial environments.

Hardwood porosity domains (diffuse-, semi-ring-, and ring-porosity) exist along a spectrum with some taxa embodying only one porosity domain and others spanning more than one. A cascading model scheme involving a root-level porosity classifier and second-level taxonomical classifiers might be useful for mitigating reductions in the predictive accuracy of North American computer vision wood identification (CVWID) models when the number of classes increases. Thus far, the porosity classifier has been trained on images covering the breadth of the porosity spectrum. By reducing ambiguity near the boundaries of porosity domains, training the root classifier only on taxa that are quintessentially diffuse-, semi-ring, and ring-porous might produce equivalent or better results. In this study, a two-class (diffuse- and ring-porous) model and a three-class (diffuse-, semi-ring-, and ring-porous) model were trained on specimens only from taxa with quintessentially idealized porosity and tested on specimens with and without idealized porosity. Results showed perfect predictive accuracy for both models when tested on in-model taxa but showed lower accuracy on datasets with non-ideal porosity with all misclassifications being anatomically sensible. In addition, the results showed remarkable similarities between CVWID models and humans in how they “apply” the concept of discrete porosity domains to a real-world continuum.

Sawmill wood waste products were used for the biosorption of nickel ions (Ni(II)) from aqueous solution in batch experiments. Effects of physical parameters such as contact time, initial metal concentration, biosorbent dosage, temperature, and pH on the biosorption capacities of both acid-activated sawmill wood waste products (ASWWP) and unactivated sawmill wood waste products (USWWP) were investigated. FT-IR analysis confirmed that hydroxyl, carbonyl, and ether groups are primary contributors to Ni adsorption, through coordination bonding and electrostatic interaction mechanisms. The surface morphology via the SEM images showed a rough, irregular surface structure with porous networks prior to adsorption, but some of the pores were blocked after adsorption. Maximum adsorption capacities of 62.3 and 76.3 mg/g were achieved at 120 and 100 min for USWWP and ASWWP at a pH of 5.0 and initial Ni concentration of 180 mg/L, respectively. The pseudo-first-order kinetic model fit well for the USWWP, whereas the pseudo-second-order kinetic model was well-suited for describing the adsorption of Ni(II) ions on  ASWWP. The values of enthalpy changes (ΔH) for USWWP and ASWWP were 10.2 and 23.4 kJ/mol, respectively, which indicated an endothermic process.

It is estimated that there are 3.1 billion pallets in circulation in the United States, and the majority of these pallets are made of wood. This research was conducted to obtain important information about the market and raw material usage trends in the wooden pallet and container industry from 2019 through 2021. The results revealed that the wooden pallet and container industry produced an estimated 919 million new pallets in 2021, which is an estimated 75% increase over 2016. The 48” x 40” pallet size continued to be the dominant new pallet size with a 29% market share. The share of softwood lumber used in the industry has steadily increased since 2016, and it accounted for 81% of the lumber used in pallet production in 2021. The industry used 38% of the total sawn softwood and hardwood lumber produced in the U.S. The industry also produced 280 million repaired and remanufactured pallets; this is a 16.4% decrease compared to 2016. Approximately 22% of respondents stated that they were not affected by the pandemic. A majority of respondents (51%) stated that they exceeded their 2019 sales, and only 12% saw no change in sales in 2020 compared to 2019.