Wood Science and Technology最新文献

Natural woods are increasingly recognized as promising green candidates for high areal capacity wood-based hard carbon thick electrodes (WHCTEs). Their unique 3-D transport network features abundant straight, open channels aligned along the longitudinal direction, which has attracted significant attention in recent years. However, direct carbonization yields underdeveloped pore structures, restricting electrochemical active surfaces and lithium storage performance. To address this issue, calcium acetate (Ca(AC)₂) was employed as a templating agent to engineer hierarchical porous architectures. Systematic studies reveal adjustable Ca(AC)₂ dosage effectively modulates pore structures, with BET analysis confirming meso-/macropore distributions (2–130 nm) in all samples. This optimized porosity reduces electrode impedance and enhances lithium storage, delivering record areal capacities of 6.81/3.89 mAh cm^-2 at 0.1/1.0 mA cm^-2, which is 190%/110% higher than commercial graphite electrode (3.5–3.6 mAh cm^-2. Kinetic analysis further identifies an “adsorption-insertion” dual lithium storage mechanism. The widely distributed porosity significantly contributes to performance improvements, demonstrating a viable strategy for developing sustainable WHCTEs. These findings provide critical insights for designing thick carbon electrodes in alkali-metal-ion batteries.

This study investigates the radial densification of spruce wood using explicit finite element method simulations, focusing on the effects of various densification protocols. These protocols include quasi-static mechanical densification, transverse vibration-assisted mechanical densification, and self-densification through shrinking hydrogel fillings and their impact on the morphogenesis of folding patterns across different tissue types. The simulations incorporate the anisotropic mechanical behavior of wood tracheid walls and account for moisture and delignification effects using a hierarchical approach. Our results reveal the technological potential of targeted densification in creating tailored density profiles that enhance stiffness and strength. These insights offer valuable guidance for optimizing densification processes in practical applications.

Concerns about environmental deterioration, resource depletion and climate change have fueled a surge in worldwide interest in sustainable materials these recent years. This interest is especially strong in businesses that rely on non-renewable resources, such as building, transportation and packaging. In this paper, there has been a process toward investigating alternative materials, which have both environmental advantages and functional capabilities equivalent to, or even superior to, traditional counterparts. This review and meta-analysis aims to assess the present status of technical research on “transparent” wood manufacture, by utilizing even recyclable polymers. This study evaluates the methods used, the attributes gained, obstacles encountered and possible uses of such new materials. A technical literature search was undertaken utilizing several databases, such as PubMed and Web of Science and pertinent scholarly journals. The inclusion criteria included peer-reviewed studies on alternative wood production utilizing various polymers. The data extraction includes polymer types, production procedures, optical and mechanical properties and limitations described in the research. Several technologies, including impregnation and hot pressing, have been used to create novel composites. “Transparent” wood composites demonstrated promising optical transparency, mechanical strength and thermal stability when compared to standard approaches. Scalability, durability and cost-effectiveness have been referred as major problems in the manufacture of “transparent” wood composites, so to the moment their market impact is low. Despite limitations, the accurate research revealed potential uses in design, renewable energy and the sustainable packaging industries.

Gabon is a tropical country with vast forested areas, covering more than 80% of its territory. These forested areas contain a wide diversity of tree species that are still little studied, particularly in terms of the ecological profile of species in relation to their technological properties. This study aimed to highlight the differences among three ecological temperaments by analyzing fifteen properties from CIRAD physical-mechanical database. The species studied were forty-eight tropical hardwoods from Gabon. The results showed differences in ecological temperaments for two of the fifteen properties selected. Shade-tolerant species had better resistance to shear than hemi-heliophilous and light-demanding species. They were also relatively more resistant to fractionation than species in the other two groups. Statistically, there was no difference between the hemi-heliophilous and pioneer groups. Most of the properties studied were positively correlated with each other, particularly the mechanical properties with density. The linear relationships between wood density, on one hand, and shear, splitting, perpendicular tension and hardness, on the other hand, were found to be dependent on ecological temperament.

This study explores how flattening transforms transverse mechanical properties of bamboo through the redistribution of vascular bundles and residual stresses. Using dual-scale characterization and mechanical testing, we reveal that: (1) Flattening enhances transverse strength, with non-notched flattened bamboo achieving peak compression strength (23.3 MPa) and tension strength (9.4 MPa), while notched flattened bamboo excels in the small-size tension test (10.8 MPa); (2) Size effects arise from structural reorganization rather than stochastic defects; (3) Specific strength analysis demonstrates the lightweight advantage of notched flattened bamboo, confirming flattening improves the intrinsic mechanical efficiency beyond densification. These mechanistic insights address critical gaps in engineered bamboo design, enabling tailored applications.

The heartwood of Wenge (Millettia laurentii) has been used as decorative fine furniture owing to its luxurious color and regular fine grain. However, over time, heartwood turns from purple-brown to dark brown and eventually fades, reducing its wood value. The structures of the pigment compounds in wood and the mechanism underlying this discoloration are unclear. Using nuclear magnetic resonance (NMR) spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), fourteen compounds (1–14), including nine new dye compounds (2–5, 8, 11–14), were identified in the methanol extract of Wenge heartwood. Among them, 2, 4, and 5 are orange isoflavane quinones; 8 and 11 are yellow flavonols; 12 is a brown pterocarpan; and 14 is a purple benzofuran quinone, which are considered characteristic of Wenge. The absolute stereoconfigurations of 2, 3, 5, and 12 were identified by comparing the calculated electronic circular dichroism (ECD) spectra with the measured values. To investigate the color-change mechanism of Wenge, the structural changes under room fluorescent light of 2, the main dye compound, was determined using NMR and MALDI-TOF-MS analysis. These results indicate the formation of dark colored pterocarpane ortho-quinone, which causes the darkening of the wood surface.

Wood is a naturally capillary absorbing material with a hierarchical structure. Understanding the orthotropic imbibition dynamics of water and corresponding swelling in wood is valuable for providing guidance for the movement of water and impregnating liquids during wood processing and utilization. In this study, we performed a one-side imbibition test with 25℃ and 50℃ water, by combining the digital image correlation (DIC) and X-ray densitometry to evaluate the orthotropic imbibition behaviour and corresponding temperature-dependent water uptake-induced swelling of Chinese fir (Cunninghamia lanceolata [Lamb.] Hook). The results showed that the water imbibition height and average moisture content (MC) at water temperature of 50℃ were higher than those at 25℃. After 24 h of imbibition, average MC at 50℃ was 1.3 to 1.9 times than at 25℃ along three directions. The enhancement of water uptake amount along the longitudinal direction by high water temperature was weaker due to the closed structure of the tracheids. Moreover, transverse swelling strain (ε_R and ε_T) was greater at higher temperature. The ε_R of latewood demonstrated stronger temperature dependence than that of earlywood, which was attributed to more swelling of the thicker cell wall due to water at higher temperature. Notably, latewood exerted a restraining effect on adjacent earlywood in transverse swelling, and the effect increased with increasing strain of latewood. A correspondence between MC and radial strain was established at growth rings level, offering theoretical guidance for understanding water movement in wood and evaluating structure-property relationships within growth rings.

Species identification is crucial in biodiversity conservation including combating the illegal trade in timbers. Traditional methods usually cannot identify timbers to the species-level and the sharp decline in the number of taxonomists has exacerbated this challenge. Several attempts have been made to utilize computer vision for wood identification, but some fundamental problems remain regarding dataset split (training, validation and test dataset), model performance, and how deep learning models interpret complex wood anatomical features. Cross-sectional images of seven endangered Pterocarpus species were obtained from the scientific wood collection (Wood Collection of Chinese Academy of Forestry), and four convolutional neural network models (ResNet-50, ResNet-152, WideResNet-50, and SEResNet-50) were trained and tested at specimen-level after image data augmentation, i.e. Crop (C), Rotating before Center Cropping (RC). Layer class activation mapping (Layer-CAM) was used to investigate diagnostic characters to identify each species. The results indicated that the accuracy of the four models was higher when the images were preprocessed using the RC strategy than C strategy. We found that WideResNet-50 identified Pterocarpus samples to 87.56% accuracy, outperforming the other three models. The heat maps showed that the models identified the same features recognized by the human eyes. All four deep learning models focused on the axial parenchyma groupings and vessel groupings of the xylem, although the features detected varied slightly for the different models. These results demonstrate that computer vision-based species identification is a practical means to identify wood samples and can be used to help prevent the illegal trade of timbers and conserve species diversity without relying on taxonomic knowledge and expertise.

Chinese fir (Cunninghamia lanceolata) wood has been widely used in structural applications owing to its excellent machinability and rapid growth. A comprehensive understanding of its mechanical behavior, particularly under compression loading, is critical for ensuring the reliability and safety of structural components. This study explored the failure behavior of Chinese fir wood under axial, radial, and tangential compression using micro-computed tomography (micro-CT) and digital volume correlation (DVC) techniques. The results revealed that Chinese fir wood exhibited high compressive stiffness under axial compression, with displacement and strain localized around inherent defects. Under radial compression, significant strain concentration was observed at earlywood tracheid lumens and growth ring interfaces, which acted as primary sites for strain localization, initiating localized failure and subsequent deformation propagation. In tangential compression, the wood demonstrated moderate compressive strength with relatively uniform deformation, although stress concentration persisted in weaker regions, particularly within earlywood tracheids. These earlywood tracheids, characterized by thinner walls and larger lumens, played a pivotal role in stress concentration and failure propagation, accelerating localized damage. This study underscores the anisotropic mechanical behavior of Chinese fir wood under compression in three directions and elucidates the associated damage evolution mechanisms, providing a theoretical foundation for evaluating its mechanical properties and guiding structural optimization.

Two new types of anthocyanidins, mopanidin (1) and peltogynidin (2) were isolated from the heartwood of Peltogyne mexicana for the first time. The structures of the isolated compounds were determined using NMR and MALDI-TOF MS analysis. These pigment compounds had flavylium moiety and oxymethylene bridge between B and C ring (D ring), and resorcinol moiety as B ring. The result of the monitoring of the oxidation of pigment precursors, it was clarified that 1 and 2 were generated from (+)-mopanol and (+)-peltogynol, respectively. The compounds were considered to be produced by light and oxygen in a different way from common anthocyanidins. Compared to cyanidin, which has similar structure except D ring, 1 and 2 showed an additional absorption around 560–570 nm to show more blueish purple. In addition, they showed more stability than cyanidin in neutral and acidic condition. Considering the result of in silico calculation of their dihedral angles consisting of the AC and B rings, 1 (θ = 174.4º) and 2 (θ = 172.0º) had a nearly planar structure, while cyanidin had a twisted structure (θ = 154.2º). It was suggested that the bulkiness around C-2 due to the nearly planar structure in 1 and 2 contributed to their relatively color stabilities in neutral condition. These findings provide insight into the structural features influencing pigment stability and color change mechanism of P. mexicana.