Volume 20 Issue 2

This study aimed to investigate the effects of wood species and lumber quality grades on the mechanical properties and costs of cross-laminated timber (CLT) panels. Various combinations of lumber with different quality grades were utilized in the layers to identify the optimal configurations for producing CLT panels with high mechanical performance and low costs. In the study, spruce and Scots pine lumber of three different quality grades (Grades 1, 2, and 3), classified according to TS 1265 standards, were used. Some mechanical properties of the CLT panels produced from lumber of varying quality grades were determined following the TS EN 408 standard. Additionally, cost analyses of the CLT panels were conducted based on the calculation of raw material costs. The results show that while higher-grade lumber improves mechanical performance, lower-grade combinations still can meet structural needs at lower costs. Mixed-grade configurations offer a balance between strength and affordability. These findings can help CLT producers optimize material selection and reduce costs while maintaining structural integrity. Using lower-grade lumber can address shortages and reduce reliance on expensive timber. Policymakers can promote sustainable forestry and lower production costs, making mass timber construction more viable and environmentally sustainable.

Exploiting stimuli-responsive Pickering interfacial catalysts is crucial to the development of organic reactions in water and green chemistry. Herein, amphiphilic carboxylated cellulose nanocrystals were synthesized by surface modification of hydrophilic carboxylated cellulose nanocrystals. The obtained amphiphilic carboxylated cellulose nanocrystals showed great toluene-in-water Pickering emulsion stabilization capacity and pH-responsive property. Emulsification and rapid demulsification behaviours were observed by simple pH adjustment. Palladium nanoparticles supported on the amphiphilic carboxylated cellulose nanocrystals exhibited high activity in the hydrogenation reaction of nitrobenzene in aqueous media because of the improved mass transfer between hydrophobic substrate and hydrophilic solvent. Moreover, the pH-responsiveness of amphiphilic carboxylated cellulose nanocrystals could promote the recovery of both products and the Pickering interfacial catalyst. Therefore, palladium nanoparticles loaded bio-derived carboxylated cellulose nanocrystals for efficient pH-switched Pickering emulsion catalytic hydrogenation was successfully prepared. Outstanding activity and reusability were achieved.

Saw wood cracks are defects that affect the appearance and mechanical strength of sawn wood. Crack defects in the surface of sawn wood can be readily detected. Decisions regarding the presence and severity of such defects can affect the utilization rate of sawn timber. Due to the heavy workload, low efficiency, and low accuracy of manual inspection, traditional machine learning methods have strong specialization, complex methods, and high costs. By studying the semantic segmentation model of surface crack defects in sawn timber based on deep learning, the optimal model for segmentation and detection of surface cracks in sawn timber was established. The improved Attention U-Net model encoding stage was introduced into CBAM, and AdamW optimization was used instead of SGD and Adam to achieve better crack semantic segmentation results. The ECA module was introduced in the skip connection part, and the weighted fusion multi loss function was used instead of the original cross entropy loss function. The positions of the two modules were replaced to improve the accuracy of semantic segmentation of surface cracks in sawn timber. Through comparative experiments, the improved model also achieved higher scores in semantic segmentation indicators for surface cracks in sawn timber compared to other models.

Lignocellulose, which consists of cellulose, hemicellulose, and lignin, has very stable properties. Among them, cellulose makes up 30% to 50% of the content, and hemicellulose makes up 20% to 43%. Cellulose and hemicellulose can be converted into fermentable sugar through saccharification, and then into bioresources through fermentation. Pretreatment methods such as high temperature and high pressure, acid and alkali cooking, enzymatic digestion can effectively decompose the lignocellulose structure, remove lignin, increase the porosity of lignocellulose, specific surface area, etc., increase the efficiency of saccharification, and improve the utilization of lignocellulose. Pretreatment is a key stage in the production process of bioresources. However, the pretreatment process produces by-products known as inhibitors such as acetic acid, furfural, and phenols. These inhibitors tend to inhibit the activity of biological enzymes, impede the saccharification of cellulose and hemicellulose, disrupt the integrity of the cell membrane of the fermenting bacteria, lead to mutation of the fermenting bacteria, and result in a decrease in the yield of the bioresource. This paper reviews recent advances in pretreatment methods, analyzes the reasons for the emergence of inhibitors, and summarizes methods to reduce the effects of inhibitors.

Sage oil plays a vital role in various fields, including health and food. The effects of UV radiation (UVR) can increase the bioactive content of medicinal plants, but there has been little research on how this affects sage oil. Therefore, this study aimed to evaluate the impact of UVR on the sage oil phytoconstituents and its biological activity. GC-MS analysis detected 20, 23, and 25 different compounds in sage un-exposed and exposed to UVR for 30 and 60 min, respectively. Candida albicans, C. tropicalis, and C. glabrata were suppressed with inhibition zones 21.62 ± 1.22, 16.20 ± 1.23, and 8.20 ± 0.66 mm by sage oil, while the exposed sage oil to UVR for 60 min exhibited 26.50 ± 1.33, 21.43 ± 2.12, and 20.25 ± 0.50 mm inhibition zone, respectively. The required IC₅₀ to inhibit butyrylcholinesterase, α-amylase, and protein denaturation was 95.3, 14.9, and 10.7 µg/mL in sage oil that was not exposed to UVR, and 35.1, 7.1, and 7.1 µg/mL in exposed sage oil to UVR for 60 min, respectively. There were negligible effects between the unexposed and exposed sage oil to UVR for 30 and 60 min against Hela cells with IC₅₀ 193.19 ± 0.98, 149.71 ± 0.18, and 148.19 ± 0.66 µg/mL, respectively.

Bamboos are a versatile non-timber subfamily that has been utilized for various purposes. Generally, bamboo leaves are used as traditional medicine to treat diseases such as cough, rheumatism, influenza, fever, skin disease, heart disease, and malaria. The bamboo extracts contain a wide range of functional groups that are responsible for pharmacological activities. The objective of this review article is to provide in-depth discussion on botany, ethnomedicinal uses, phytochemical constituents, pharmacological properties, and toxicity of bamboo plant extract. Phytochemical studies showed that a total of 21 functional groups were detected from bamboo leaves, stems, and seeds. In addition, volatile compounds that produce aromatic odor also were detected from the bamboo extract. Meanwhile, pharmacological studies revealed that bamboo extract exhibited several pharmacological properties including anti-diarrheal, analgesic effect, antimalarial, anti-ulcer, anti-inflammatory, anti-bacterial, anti-fungal, anti-diabetic, wound healing, anticancer, and hepatotoxicity. The toxicity study found that bamboo extract is safe for consumption and did not show harmful effects. A review of phytochemical constituents and pharmacological properties in plants is important for several purposes such as new drugs discovery and understanding the mechanisms, safety, and efficacy of the bioactive compounds to treat various diseases.

Self-tapping screws and round steel nails were driven into Pinus massoniana and Cunninghamia lanceolata dimension lumber pieces to explore the influence of intersection angle on nail-holding performance, expecting to provide a more complete scientific basis for the connection of wood structures. The results showed that (1) as the intersection angle declined, the nail-holding strength of self-tapping screws for both P. massoniana and C. lanceolata dimension lumber gradually decreased. At the intersection angle of 90°, nail-holding strength was the maximum, being 79.8 and 80.5 N/mm, respectively; (2) With the reduction of the intersection angle, the nail-holding strength of round steel nails for both dimension lumber initially increased and then gradually declined. The maximum nail-holding strength (21.0 N/mm) of P. massoniana appeared at the intersection angle of 45° while that (22.3 N/mm) of C. lanceolata appeared at 60°; (3) No matter for self-tapping screws or round steel nails, the rigidity at the connection point was the greatest at the intersection angles of 90° and 0° (cross-section). If diagonally nailed into lumber, both self-tapping screws and round steel nails can enhance the ductility of connection joints, where the former exerts a more evident effect.

Timber has been studied as a material of construction from many perspectives, including strength and durability. Despite many studies showing a good correlation between material models, connection behaviour, and structural modelling, it is still not clear which approach is suitable under what constraints. This study was performed to clarify the problem. The basis for the analysis of timber structures is emphasized in this work in terms of problem dimension, material constitution, and geometrical nonlinearities. The modelling and the idealisation methods of structures are categorised into five different groups and briefly explained. An experiment available in the literature is used as a reference to illustrate modelling capabilities of different techniques, and models from five different groups is used to perform analysis. By comparing the analysis results and the experiment, key notes on the analysis proficiency are highlighted, including failure load, maximum displacement, and failure mode. The results show that most of the errors occurred in the displacements. Furthermore, the divergence between test and analysis results are investigated, and an approximate method for calculating actual displacements is proposed.

Populus cathayana Rehder (PCR, Chinese poplar), Fraxinus chinensis Roxb. (FCR, Chinese ash), Platanus orientalis L. (PO, Oriental plane), and Acer palmatum Thunb. (AP, Japanese maple) are four common hardwoods in the northern hemisphere. In this work, chemithermomechanical pulps (CTMP) of the four wood species were prepared for comparative study of pulp properties. For unbleached CTMP, PCR and FCR exhibited the highest whiteness of 44%ISO, while AP demonstrated the highest tensile index of 24.2 N·m²/g, tear index of 1.23 mN·m2/g, and ring crush index of 7.2 N·m/g. For bleached CTMP using hydrogen peroxide, PO achieved the highest whiteness of 70.3% ISO at 6% hydrogen peroxide. AP showed the optimal tensile index of 24.7 N·m²/g. The experiments also revealed that PO exhibited the highest bulk of 3.6 cm³/g. This study provides a reference for selecting raw materials in pulp production.

This review article considers the formulation of a broad range of coatings designed for the protection and changing the appearance of wood surfaces. Findings from the literature are considered from the standpoint of the main chemical components, how they can be formulated into a spreadable product, the events leading to curing, and factors affecting the performance of the resulting coating layers on wood surfaces. A series of hypotheses are considered, relating to the mechanisms underlying wood coating products and their usage. Special attention is paid to the topics of adhesion at the coating-wood interface, the development of film strength and hardness, and challenges related to the past and continuing development of waterborne coating formulations. The modern technologist seeking to coat wood has many options to choose from, and there has been a need to make current knowledge related to the field more available to the wider scientific community.