Search Results (43)

To enhance the interfacial bonding between bamboo and the polymer matrix in natural fiber composites (NFCs), vacuum heat treatment was applied to moso bamboo strips at temperatures ranging from 140 to 180 °C with holding times of 4 and 6 h. The effects of treatment conditions on the surface characteristics and chemical composition of bamboo were systematically investigated. Scanning electron microscopy (SEM), contact angle measurements, and Fourier transform infrared spectroscopy (FTIR) were employed to evaluate the changes in microstructure, surface wettability, and the main functional groups including α-cellulose, hemicellulose, and lignin. The results indicate that the severity of heat treatment (temperature–time combination) significantly influences the physicochemical properties of bamboo. Hemicellulose, which exhibited the lowest thermal stability, underwent pronounced degradation above 140 °C and showed the most substantial compositional variation. Although the relative contents of α-cellulose and lignin increased with increasing treatment severity, their absolute contents decreased. The vacuum environment was found to retard the degradation of α-cellulose to some extent. At 180 °C, severe disruption of the cell wall structure was observed, accompanied by the deformation and collapse of cell lumens. In addition, heat treatment increased the surface contact angle, indicating enhanced hydrophobicity, with temperature exerting a more pronounced effect than treatment time. FTIR analysis revealed a marked reduction in the intensity of the C=O stretching vibration of hemicellulose (~1730 cm⁻¹) and the O–H stretching vibration (~3400 cm⁻¹), while the aromatic structure of lignin remained relatively stable. Overall, vacuum heat treatment effectively enhanced the surface hydrophobicity of bamboo, providing a theoretical basis and technical support for the development of bamboo-reinforced natural fiber composites. Full article

This study focuses on the surface materials of rammed-earth walls of Fujian Tulou in Xiaoshu Village, exploring the microscopic characteristics of rammed earth in different orientations and the microclimate adaptation mechanism and degradation law of the walls. Specimens were collected from the inner and outer surface soil layers of the four directional walls of a representative Tulou. SEM, XRD, and XRF analyses were performed to characterize the materials’ microstructure, mineral composition, and elemental distribution, with the test results correlated to the microclimatic conditions of each wall orientation. The conclusion is as follows: (1) The microscopic particle size of rammed earth exhibits significant directional differences at dual scales of 300 nm and 2 μm. Solar radiation duration and wind speed are positively correlated with the coefficient of variation in particle size. (2) The southeast and north walls were the most severely damaged (soil loss, quartz enrichment: 79.9%), the west wall had minor cracks, the north wall showed slight salt crystallization (Halite = 0.3%), and the east wall exhibited moisture-related moss growth. (3) Traditional organic additives (bamboo strips, rice husks) mitigate deterioration and enhance structural integrity. (4) The diversity of soil color (related to hematite and iron oxide) can serve as a simple indicator of deterioration. This study has proposed differentiated protection schemes for the “microclimate-compounds” on walls facing different directions on the rammed-earth surface of the Tulou. The findings provide a theoretical basis for orientation-specific conservation of Tulou heritage and offer scientific references for the modification of modern rammed-earth materials. Full article

Moso bamboo (Phyllostachys edulis) harvesting is labor-intensive and inefficient, while strip-cutting enables mechanized, cost-effective management and supports long-term production. Intensive strip-cutting disturbs bamboo ecosystems, altering soil, litter and understory vegetation. This may reduce long-term productivity despite moso bamboo’s rapid growth, especially in the mountainous areas like Anji, Zhejiang. To balance ecological and production goals, we evaluated strip-cutting widths of 3, 5, and 8 m under three slope classes, 5–14° (gentle, SL1), 15–24° (moderate, SL2), and 25–34° (steep, SL3), focusing on bamboo growth recovery and understory vegetation diversity. Compared with uncut control plots, the number of herbaceous and shrub species increased in all treatment plots. In 5 m moderate slope plots, shoot and culm numbers were 27% and 13% higher than those in the 3 m and 8 m plots, and 37% higher than uncut control plots. Herb species diversity, as reflected by the Shannon–Wiener (H′), Simpson (D), and Margalef richness (R) indices, was high in the narrowest clearcut strips under SL1 and SL3. Pielou’s evenness index (J) was high in the 3 and 5 m plots under SL2 and SL3. Shrub species diversity, as indicated by D and R, was high in 5 and 8 m plots under SL2 and SL3. Principal component analysis (PCA) indicated that under SL2, 5 m strip-cutting width with a score of 0.649 outperformed others. These results suggest that 5 m strip-cutting width under SL2 slope optimizes understory vegetation diversity and supports a synergistic outcome of “high shoot emergence–high culm formation” thereby achieving both ecological and production benefits. Full article

After rough planing, defects such as wormholes and small patches of green bark residue and decay are often overlooked and misclassified. Strip-like defects, including splinters and chipped edges, are easily confused with the natural bamboo grain, and a single elongated defect is frequently fragmented into multiple detection boxes. This study proposes a modified TASNet-YOLO model, an improved detector built on YOLO11n. Unlike prior YOLO-based bamboo defect detectors, TASNet-YOLO is a mechanism-guided redesign that jointly targets two persistent failure modes—limited visibility of small, low-contrast defects and fragmentation of elongated defects—while remaining feasible for real-time production settings. In the backbone, a newly designed TriMAD_Conv module is introduced as the core unit, enhancing the detection of wormholes as well as small-area defects such as green bark residue and decay. The additive-gated C3k2_AddCGLU is further integrated at selected C3k2 stages. The combination of additive interaction and CGLU improves channel selection and detail retention, highlighting differences between splinters and chipped edges and bamboo grain strips, thereby reducing false positives and improving precision. In the neck, the neck replaces nearest-neighbor upsampling and CBS with SNI-GSNeck to improve cross-scale alignment and fusion. Under an acceptable real-time budget, predictions for splinters and chipped edges become more contiguous and better aligned to edges, while wormholes predictions are more circular and less noisy. Experiments on our in-house dataset (8445 bamboo-strip defect images) show that, compared with YOLO11n, the proposed model improves detection accuracy by 5.1%, achieves 106.4 FPS, and reduces computational costs by 0.4 GFLOPs per forward pass. These properties meet the throughput demand of 2 m/s conveyor lines, and the compact model size and compute footprint make edge deployment straightforward for fast online screening and preliminary quality grading in industrial production. Full article

The accurate detection of surface defects in bamboo is critical to maintaining product quality. Traditional inspection methods rely heavily on manual labor, making the manufacturing process labor-intensive and error-prone. To overcome these limitations, TEB-YOLO is introduced in this paper, a lightweight and efficient defect detection model based on YOLOv5s. Firstly, EfficientViT replaces the original YOLOv5s backbone, reducing the computational cost while improving feature extraction. Secondly, BiFPN is adopted in place of PANet to enhance multi-scale feature fusion and preserve detailed information. Thirdly, an Efficient Local Attention (ELA) mechanism is embedded in the backbone to strengthen local feature representation. Lastly, the original CIoU loss is replaced with EIoU loss to enhance localization precision. The proposed model achieves a precision of 91.7% with only 10.5 million parameters, marking a 5.4% accuracy improvement and a 22.9% reduction in parameters compared to YOLOv5s. Compared with other mainstream models including YOLOv5n, YOLOv7, YOLOv8n, YOLOv9t, and YOLOv9s, TEB-YOLO achieves precision improvements of 11.8%, 1.66%, 2.0%, 2.8%, and 1.1%, respectively. The experiment results show that TEB-YOLO significantly improves detection precision and model lightweighting, offering a practical and effective solution for real-time bamboo surface defect detection. Full article

Pile–raft foundations are widely used in soft soil engineering due to their good integrity and high stiffness. However, traditional design methods independently design pile–raft foundations and superstructures, ignoring their interaction. This leads to significant deviations from actual conditions when the superstructure height increases, resulting in excessive costs and adverse effects on building stability. This study experimentally investigates the interaction characteristics of pile–raft foundations and superstructures in soft soil under different working conditions using a 1:10 geometric similarity model. The superstructure is a cast-in-place frame structure (beams, columns, and slabs) with bamboo skeletons with the same cross-sectional area as the piles and rafts, cast with concrete. The piles in the foundation use rectangular bamboo strips (side length ~0.2 cm) instead of steel bars, with M1.5 mortar replacing C30 concrete. The raft is also made of similar materials. The results show that the soil settlement significantly increases under the combined action of the pile–raft and superstructure with increasing load. The superstructure stiffness constrains foundation deformation, enhances bearing capacity, and controls differential settlement. The pile top reaction force exhibits a logarithmic relationship with the number of floors, coordinating the pile bearing performance. Designers should consider the superstructure’s constraint of the foundation deformation and strengthen the flexural capacity of inner pile tops and bottom columns for safety and economy. Full article

Fully bio-based composites were obtained from continuous bamboo strips and flame-retardant polyamide 11 (PA11-FR) matrix. A mercerization treatment was performed on the bamboo strips surface to optimize fiber-matrix interactions. Composites were obtained by thermocompression molding with two pressure plateaus. The influence of the concentration of NaOH solution treatment was analyzed. The thermogravimetric analysis highlighted that the mercerization treatment removes part of hemicellulose, low molecular weight lignin and amorphous cellulose, while crystalline cellulose is preserved. Dynamic mechanical analysis performed in the shear configuration revealed the level of interactions between bamboo strips and PA11-FR matrix. The glassy modulus was improved for the composites compared to the matrix and their rubbery modulus was increased by a factor 4.6. Composites with bamboo strips treated at 1% NaOH showed the highest shear modulus across the entire temperature range with an increase by a factor of 1.39 on the glassy plateau and 1.3 on the rubbery plateau, with the untreated bamboo strips/polyamide 11-FR composite as reference. Water uptake was analogous for composites and bamboo strips, so the shear modulus at room temperature was not impacted by moisture. Full article

It is difficult to detect several detailed defects when detecting surface defects in bamboo strips. The morphology of these defect characteristics exhibits relatively simple patterns but closely resembles the underlying fiber texture or coloration, as exemplified by cracks, mildew, wormholes, and burr formation. In this regard, this study proposes an improved model based on the YOLOv8 deep learning network. The improved model uses dynamic convolution and a Ghost module to improve the C3k2 modules in YOLOv8 to reconstruct its backbone and neck parts, where the research introduces the DySample module to replace the original upsample module to avoid the loss of feature information of targets after the network is used multiple times, further ensuring the detection effect of detailed features, as well as the EMA mechanism in the neck part. Experimental validation of the developed model demonstrated robust detection performance, achieving mAP values of 93.1%, 92.9%, 92.2%, and 92.2% for burr, mildew, cracking, and wormhole detection, with a total mAP of 92.6% and a precision of 81.5%; at the same time, the weight was decreased by 14%. The experimental results show that the improved model in this study has a certain detection effect on difficult-to-identify features on the surface of bamboo strips. This research demonstrates that employing YOLOv8 helps in detecting several challenging minor defects in bamboo strips. Full article

The study evaluates the mechanical properties of a woven bamboo structure made from bamboo strips using an analytical relation and finite element simulation. The bamboo studied is a recently discovered species, Bambusa Nghiana, characterized by long internodes. Bamboo strips have lower strength at the node junctions, a feature that can be advantageous for this species due to its extended internode length. Plain weave bamboo structures were handwoven from thin, rectangular bamboo strips cut from the bamboo culm along the radial direction. The high bending rigidity of the bamboo strips resulted in an asymmetric woven structure with curved warp strips and straight weft strips. The stiffness of the woven structure was correlated with the stiffness of the bamboo strips and the weave geometry. The in-plane shear resistance of the woven structure was significantly lower than its axial stiffness due to the asymmetric weaving. These in-plane properties were validated using finite element simulation through a user subroutine incorporating the woven structure and the Hashin damage criteria. The prediction of the puncture simulation showed good agreement with the corresponding experiment. These results confirm the proposed analytical relation between the mechanical properties of individual bamboo strips and those of the woven structure. Full article

This study investigates the structural behavior of bahareque earth walls, a traditional construction system commonly used in rural areas of northern South America. Bahareque (wattle and daub) walls, consisting of guadua (a bamboo-like material) or wooden frames filled with soil mixes, have demonstrated considerable resilience in seismic zones due to their lightweight and flexible nature. Despite their widespread use in these communities, limited scientific data exist on their seismic performance under in-plane pseudo-static horizontal loading. This research addresses this gap by experimentally evaluating the seismic behavior of five wall models with different combinations of guadua, wood, and earth filling materials. The methodology included four main phases, namely field visits to document traditional construction techniques, material characterization, prototype testing under pseudo-static loads, and an analysis of mechanical behavior. Key material properties, including compressive strength and Young’s modulus, were determined, alongside the mechanical and physical properties of the infill material, which incorporated natural fibers. Pseudo-static tests were conducted on five wall prototypes, featuring various configurations of guadua and wood frameworks, both with and without soil infill. The walls were subjected to horizontal in-plane loads to assess their deformation capacity, energy dissipation, and failure mechanisms. The results indicated that walls with soil mixture infill—specifically the GSHS (guadua frame with horizontal guadua strips and soil mixture infill) and TSHS (wood frame with horizontal guadua strips and soil mixture infill) configurations—demonstrated the best seismic performance, with maximum displacements reaching up to 166 mm and strengths ranging from 6.4 to 8.4 kN. The study concludes that bahareque walls, particularly those incorporating soil mixes and horizontal guadua strips, exhibit high resilience under seismic conditions and provide a sustainable construction alternative for rural regions. The scope of this study is limited by the exclusion of dynamic seismic simulations, which could offer additional insights into the behavior of bahareque walls under real earthquake conditions. The novelty of this research lies in the direct evaluation of the seismic performance of traditional bahareque configurations, specifically comparing walls constructed with guadua and wooden frameworks, while emphasizing the critical role of soil infill and guadua strips in structural performance. Full article

Restoring the degraded habitat of the giant panda (Ailuropoda melanoleuca) is of paramount importance for the conservation of the species and its forest ecosystem. However, little is known about the impact of ecological restoration interventions on the growth renewal and nutritional quality of Arundinaria faberi in the degraded habitat of the giant panda. Here, we implemented strip thinning and blocky thinning techniques in the Daxiangling mountain range, alongside a control group. A random forest model and multiple linear regression analysis were employed to predict changes in the growth renewal and nutritional quality of bamboo, particularly in the strip-thinned zones. The key findings were as follows: (1) Compared with the control area, strip thinning increased the number of shoots and increased the diameter and height of shoots. (2) The random forest model predicted a decline in bamboo regeneration indices in 2023 compared to 2022 under strip thinning. (3) Through thinning, the palatability and nutritional level of A. faberi were improved. (4) Long-term effects included increased tannin in leaves, decreased tannin and amino acids in shoots and culms, and increased crude fat, with changes in crude protein distribution across bamboo parts. Overall, these findings provide valuable insights for habitat restoration efforts targeting giant panda populations in the low-canopy forest ecosystems of the Daxiangling mountain range. Full article

At present, bamboo fiber is mainly prepared by rolling and carding after employing the alkali boiling softening method, which is not friendly to the environment. In order to obtain a green and environmentally friendly pretreatment method for preparing bamboo fiber, this paper starts with the current bamboo softening technology and explores the impact of various experimental factors on fiber extraction of Pleioblastus amarus (bitter bamboo) after application of the saturated steam softening method through studying the relationship between saturated steam temperature, holding time, moisture content of bamboo strips, fiber yield, fiber fineness, and the mechanical properties of Pleioblastus amarus fiber. Single-factor experiments revealed that optimal softening fiber extraction effects were achieved within a steam temperature range of 150–180 °C, a holding time of 10–30 min, and a moisture content of 12%–22%. Based on these findings, an orthogonal experiment was designed using a factorial-level table. Through the analysis of range, variance, and orthogonal experiment results, combined with the fibrillation effect and the practical application of fibers, the optimal process parameters of the saturated steam softening method for fiber extraction were determined: saturated steam temperature 170 °C, holding time 20 min, and moisture content 12%. In contrast to the method of conventional mechanical fiber extraction after alkali boiling softening treatment, bamboo fibers processed utilizing the optimized conditions of the saturated steam softening technique showcase a substantial 63% elevation in fiber yield, a notable 18% reduction in fiber fineness, a commendable 28% enhancement in fiber tensile strength, an equivalent tensile modulus, and a marked 53% decrease in elongation at break. The softening process can provide a green and environmentally friendly treatment method for bamboo fiber extraction and greatly promote the scope of application of Pleioblastus amarus. Full article

This paper investigates the effect of innovative cross-sectional configurations on Low-Cost Bamboo Composite (LCBC) structural members. The study employs both experimental and numerical methods with different resin matrices and bamboo species. In this study, LCBC short columns are designed with different innovative cross-sectional configurations in an attempt to overcome the costly production processes of engineered bamboo. This approach uses bundles of bamboo, both in culm and strip forms. A compatible, environmentally responsible, and economically justifiable resin matrix is used to fabricate an LCBC member. The production of LCBC members does not necessitate highly advanced technology. This capability enables the production of LCBC members in custom-designed cross-sectional shapes and lengths. This study introduces the Russian doll (RD), Big Russian doll (BRD), Hawser (HAW), and Scrimber (SCR) cross-sectional configurations. Extra-large, large, medium, and small sizes of bamboo are employed. Synthetic Epoxy (EXP), a Bio-based Experimental soft filler (BE1), Bio-Epoxy (BE2), Furan-based (PF1) matrices are applied. Furthermore, Moso, Guadua, Madake, and Tali bamboo species are incorporated. The results of this study reveal that the most efficient cross-sectional configuration for compressive strength is the HAW configuration, closely followed by the SCR configuration. LCBC members with bio-resins have shown excellent promise in competing in strength with those made with their synthetic counterparts. The maximum compressive strengths (MPa) were achieved by two specimens with synthetic epoxy closely followed by a specimen with bio-epoxy, namely HAW-EPX-M, RD-EPX-M, and RD-BE2-G specimens with 78 MPa, 75 MPa, and 72 MPa, respectively. In terms of the modulus of elasticity of LCBC with different resin matrices, the stiffest specimens were HAW-BE2-M1, HAW-EPX-M, and HAW-BE2-M2 with 3.89 GPa, 3.08 GPa, and 2.54 GPa, respectively. The theoretical and numerical modelling of the LCBC members showed excellent correlation with the experimental results, which provides the capacity to design LCBC for engineering projects. The LCBC design can be further developed with more bamboo and less resin content. Full article

Detecting surface defects in bamboo strips is essential for producing Asian bamboo products. Currently, the detection of surface defects in bamboo strips mainly relies on manual labor. The labor intensity is high, and the detection efficiency is low. Improving the speed and accuracy of identifying bamboo strip defects is crucial in enhancing enterprises’ production efficiency. Hence, this research designs a lightweight YOLOv5s neural network algorithm using the Ghost module to identify surface defects of bamboo strips. The research introduces an attention mechanism CA module to improve the recognition ability of the model target; the research also implements a C2f model to enhance the network performance and the surface quality of bamboo strips. The experimental results show that after training with the acquired image dataset, the YOLOv5s model can exert an intelligent detection effect on five common types of defects in bamboo strips, and the Ghost module makes YOLOv5s lightweight, which can effectively reduce model parameters and improve detection speed while maintaining recognition accuracy. Meanwhile, the C2f module and CA module can further leverage the model’s ability to identify specific defects in bamboo strips after lightweight improvement. Full article

Bamboo is a typical natural fiber-reinforced composite with excellent mechanical properties, which are determined by its special micro-structure. As the reinforcing phase, the vascular bundles play a central role in the control of the mechanical properties of bamboo macro-structure. To find the exact gradient variation of the mechanical properties of these continuously distributed vascular bundles within the bamboo culm, 4-year-old Moso bamboo was chosen to investigate the variation of locate-distribution, cross-section area, and mechanical properties of single vascular bundles along the longitudinal and radial directions with respect to their location from the base, middle, and top sections of bamboo culm, respectively. It shows that the spatial distribution of vascular bundles along the column is distributed exponentially from the inside to the outside of the culm. The cross-section area of the vascular bundles decreased exponentially from the inside to the outside along the radial direction. All the vascular bundles were then carefully separated from bamboo strips and tested via the tensile tests. Test results show that the longitudinal tensile strengths of vascular bundles ranged from 180.44 to 774.10 MPa, and the longitudinal Young’s modulus ranged from 9.00 to 44.76 GPa. The tensile strength of vascular bundles at the outer side was three times higher than that of the inner side, while Young’s modulus at the outer side was three to four times higher than that of the inner side. For all three height positions, the strengths and Young’s modulus of vascular bundles are all exponentially increased from the inner side to the outer side along the radial direction. This work will provide a basis for the highly processed product’s application of bamboo resources and a reference for further study on the trans-scale analysis of the mechanical properties of bamboo. Full article