Search Results (2,052)

To address the trade-off between storage stability and curing reactivity in NCO-terminated waterborne polyurethane (WPU) systems, a solvent-free WPU emulsion with dual-curing characteristics was developed using vanillin (VAN) and 2-hydroxyethyl acrylate/pentaerythritol triacrylate (HEA/PETA). Hexamethylene diisocyanate (HDI) and 2,2-bis(hydroxymethyl)butyric acid (DMBA) were used as the isocyanate component and internal hydrophilic moiety, respectively, to prepare a self-dispersible polyurethane prepolymer. VAN was introduced as a latent isocyanate-related component, while HEA/PETA served as acrylate-bearing reactive modifiers, followed by self-emulsification to form a stable aqueous dispersion. The prepolymer structure, curing behavior, and adhesive performance on bamboo substrates were systematically investigated. The results supported the successful introduction of VAN-derived structures into the polyurethane chains and the retention of polymerizable C=C bonds from HEA/PETA. Thermal analysis suggested dual-curing behavior with two distinguishable thermal events, involving lower-temperature polymerization of unsaturated groups and a VAN-related higher-temperature reaction. The resulting WPU exhibited dry and wet shear strengths above 23 MPa and 9 MPa, respectively. These findings demonstrate a feasible strategy for integrating emulsion stability, staged curing, and adhesive performance in solvent-free WPU systems. Full article

The nominal maximum aggregate size (NMAS) plays a critical role in determining the mechanical performance of cement-stabilized macadam (CSM), yet its meso-mechanical influence mechanism remains insufficiently understood. In this study, three skeleton-dense CSM mixtures with different NMAS values were designed, and a combined experimental–numerical approach was adopted to investigate the macro- and meso-scale mechanical behavior. Uniaxial compression tests and aggregate crushing value tests were conducted to evaluate strength development and load-transfer characteristics, while a three-dimensional discrete element method (DEM) model incorporating realistic aggregate morphology was established to analyze the evolution of contact forces and crack propagation. The results show that increasing NMAS significantly improves the mechanical performance of CSM. Compared with CSM-30, the 7-day compressive strength of CSM-40 and CSM-50 increased by approximately 10.3% and 37.3%, respectively. The stress–strain response indicates that mixtures with larger NMAS exhibit higher stiffness and a higher strain. At the meso-scale, a larger NMAS promotes the formation of a more efficient force-chain network dominated by coarse aggregates. Strong contacts were predominantly carried by aggregates larger than 9.5 mm, and in CSM-50, the proportion of strong contacts in the 37.5–53 mm fraction exceeded 90%, indicating that the largest particles likely form the primary load-bearing skeleton. In addition, increasing NMAS delayed crack initiation, reduced crack propagation rate, and decreased the total number of cracks at failure. These findings demonstrate that macroscopic strength improvement is closely associated with meso-scale optimization of the aggregate skeleton and enhanced load-transfer efficiency. This study provides a mechanistic basis for NMAS selection and gradation optimization in semi-rigid base materials. Full article

China has rich bamboo resources, with Moso bamboo (Phyllostachys edulis) being the most economically important species. Bamboo shoot bud development directly determines the eating quality of the shoots and the properties of bamboo materials; however, the intrinsic biological characteristics of this process have hindered foundational research. Traditional methods using whole shoot buds or mixed tissues obscure cellular and tissue heterogeneity, limiting our mechanistic understanding. This review synthesizes cytological features, molecular networks, and technical limitations pertaining to Moso bamboo shoot bud development, identifying four key bottlenecks: tissue homogenization masking cellular heterogeneity, loss of spatial positional information impeding analysis of position effects, challenges in single-cell technology application due to sample preparation and data interpretation issues, and unresolved coupling between chromatin accessibility and transcriptional regulation. To address these, we propose a core strategy centered on constructing a single-cell resolution, spatially resolved, multi-omics integrated, and functionally validated framework. Key approaches include developing bamboo-specific single-cell sequencing and spatial transcriptomics, integrating positional information with multi-omics data to identify spatially distinct regulatory targets, standardizing technical pipelines and functional validation platforms, and elucidating epigenetic–transcriptional coupling. Overcoming these bottlenecks will reveal the molecular basis of bamboo’s unique developmental patterns and provide key targets for the genetic improvement of the shoot quality and mechanical properties of bamboo. Full article

Bamboo surfaces are susceptible to scratches and contamination during service, which limits their durability and aesthetic performance. To address this issue, this study aims to develop a natural self-healing coating based on tung oil microcapsules. Tung oil microcapsules encapsulated within chitosan and gum arabic (TO/CS–GA MCs) were prepared by spray drying at two feed rates (100 and 200 mL h⁻¹) and incorporated into tung oil coatings applied on bamboo substrates. The effects of microcapsule content (1.0–11.0 wt%) and feed rate on the optical performance, mechanical performance, and self-healing performance of the coatings were systematically investigated. The results showed that increasing the microcapsule content gradually increased the color difference (ΔE) and surface roughness of the coatings, while the gloss decreased. The hardness, impact resistance, adhesion grade, and self-healing efficiency of the coatings exhibited a similar trend, initially increasing and then decreasing with increasing microcapsule content. This behavior indicates that an appropriate amount of microcapsules can enhance the coating performance, whereas excessive addition leads to particle agglomeration and structural defects. Under the better condition of 5.0 wt% microcapsule content and a spray-drying feed rate of 100 mL h⁻¹, the coating exhibited the best overall performance, including higher gloss retention, a hardness of 2H, an impact resistance of 3 kg·cm, relatively low surface roughness, and a self-healing efficiency of 28.16 ± 0.63%. These results suggest that the spray-drying feed rate plays an important role in regulating the particle size distribution and encapsulation efficiency of the microcapsules, which in turn affects their dispersion and rupture–release behavior within the coating matrix. Therefore, controlling the spray-drying parameters is crucial for optimizing the performance of microcapsule-based self-healing coatings. Overall, this study provides a sustainable strategy for developing natural polymer-based self-healing coatings and offers useful insights into the design of functional microcapsules for bamboo surface protection. Full article

Lycoris plants are known for their diverse flower colors, but the molecular mechanisms behind these variations remain unclear. In this study, we first used the CIELAB system to precisely measure flower color. We objectively defined the petals of Lycoris sprengeri as blue-purple (Bp) and compared them with the white petals of Lycoris longituba (W) and the red petals of Lycoris radiata var. pumila (R). Metabolomic analysis showed that specific kaempferol glycosides, including kaempferol-3-O-sophoroside and lonicerin, accumulated significantly in the blue-purple petals. Transcriptomic analysis revealed that genes related to flavonoid biosynthesis were generally more active in the colored petals (Bp and R). However, different expression patterns of key hydroxylase genes created a metabolic split. Specifically, the blue-purple petals showed high expression of LrF3′5′H (directing synthesis toward delphinidin) and LrFLS (promoting kaempferol accumulation), whereas the red petals mainly expressed LrF3′H (leading to cyanidin synthesis). Further investigation identified LrWRKY70 as a core transcription factor highly correlated with these flavonoid pathway genes. Crucially, we discovered a new long non-coding RNA, LncRNA401, located downstream of the LrWRKY70 antisense strand. It showed a strong positive correlation with LrWRKY70. Functional verification through transient overexpression demonstrated that LncRNA401 significantly increased the expression of LrWRKY70. This, in turn, broadly activated downstream flavonoid biosynthesis genes, including LrCHS, LrF3′5′H, LrFLS, and LrDFR. This cascade ultimately promoted the synthesis of anthocyanins and kaempferol derivatives, resulting in the unique blue-purple phenotype. Our results reveal a novel LncRNA401-LrWRKY70 regulatory module. This module plays a key role in metabolic reprogramming for flower color formation in Lycoris, providing important insights into plant secondary metabolism and valuable targets for breeding specific flower colors. Full article

The eco-health effects of urban green spaces are playing a vital role in mitigating urban environmental stress and promoting residents’ well-being. However, the specific differences and dominant factors influencing these effects across different green space types and plant community structures have not been fully elucidated. This study selected three typical green spaces in Tianfu New District of Chengdu—regional green space, comprehensive park, and specialized park—and focused on four community structures: tree–shrub–herb, tree–herb, tree-only, and herb-only. Multi-scale in situ monitoring was conducted during summer, and a comprehensive index method was employed for evaluation. The results demonstrated that (1) the tree–shrub–herb multi-layered structure exhibited the optimal eco-health function at the community scale, with a PM_2.5 reduction rate of 73.86%, a noise reduction rate of 25.13%, and a negative air ion supply rate of up to 396%, significantly outperforming other structures. (2) The overall effect of regional green space (composite index 10.41) at the site scale was significantly higher than that of comprehensive parks (6.42) and specialized parks (5.87), respectively. (3) The eco-health effect increased with the complexity of the community structure, ranking as: tree–shrub–herb > tree-only > tree–herb > herb-only, highlighting the prominent contribution of the tree layer. Plant diversity showed a positive but non-significant trend. In conclusion, this multi-scale comparative study clarifies the differential impacts of green space types and community structures on the eco-health effect. It is recommended that urban planning prioritizes the layout of regional green spaces and adopts the tree–shrub–herb multi-layered structure as the dominant configuration in design in order to enhance the eco-health effect. Full article

Intensive nitrogen (N) fertilization in Phyllostachys edulis (Carrière) J.Houz. forests increases productivity but also accelerates nitrous oxide (N₂O) emissions, posing a challenge to balancing forest yield with environmental sustainability. Silicon (Si), a beneficial element for bamboo, has emerged as a potential regulator of soil nitrogen (N) cycling, but its role in controlling N₂O emissions in forest ecosystems is not fully understood. In this study, we conducted a factorial pot experiment using P. edulis forest soil, with data collected over two years, but only the second-year results were analyzed, with controlled N (0, 80, and 160 mg kg⁻¹) and Si (0, 25, and 50 mg kg⁻¹) additions. The experiment lasted two years, but only the second-year data were used for analysis. We investigated how Si affected soil inorganic N dynamics, enzyme activities, plant growth, and cumulative N₂O emissions. Si addition significantly reduced N-induced N₂O emissions by up to 53%, with the strongest mitigation observed under moderate N input (p < 0.05, two-way ANOVA). This effect was associated with lower activities of AMO, NaR, and NiR, together with reduced availability of oxidized N substrates, indicating that Si mitigated N₂O emissions mainly by constraining upstream N transformation processes rather than by directly suppressing N₂O fluxes. Si addition also tended to promote plant biomass accumulation. These findings suggest that integrating Si fertilization into bamboo forest management may help improve nutrient use efficiency while mitigating greenhouse gas emissions. Full article

The escalating global demand for sustainable and disaster-resilient housing has renewed interest in bamboo-based construction systems, particularly composite bamboo shear wall (CBSW) panels as low-carbon alternatives to conventional materials. Despite their potential, systematic data on the shear performance of such panels remains limited, especially regarding the influence of cross-bracing on strength, stiffness, ductility, dissipated energy, and damage behavior under lateral loading. This study addresses this gap through experimental characterization of full-scale CBSW panels. Two configurations, with (WT1) and without (WT2) flat steel bar cross-bracing, were tested under monotonic and cyclic loading. WT1 panels consistently exhibited a higher characteristic shear strength and capacity, and initial stiffness than WT2. WT2 panels showed greater ductility through more distributed deformation. Both configurations displayed gradual strength deterioration post-peak. The Energy Equivalent Elastic–Plastic (EEEP) method yielded higher and more conservative estimates of yield load and displacement compared to the conventional approach. These findings demonstrate that CBSW panels, particularly WT1, offer viable lateral resistance for low-rise structures in seismic-prone regions. Full article

To develop a fully green and non-toxic wood adhesive with improved water resistance and bonding performance for soybean meal (Glycine max (L.) Merr.)-based adhesives, oxidized tannin (OTN) was obtained by the laccase treatment of waxberry tannin (TN), a natural polyphenolic polymer, and then blended with soybean meal (SM) to prepare an oxidized tannin–soybean meal adhesive (OTS). Laccase-mediated oxidation converted the tannin polymer into quinone-rich oxidized polymeric structures, which reacted with amino groups in soybean meal proteins through Michael addition and Schiff base reactions to form a covalently crosslinked polymeric network. Under the optimal conditions of a laccase dosage of 10%, an oxidation time of 6 h, an OTN:SM mass ratio of 0.5:1, and a hot-pressing temperature of 160 °C, plywood bonded with OTS exhibited a wet shear strength of 0.85 MPa at 63 °C, representing a 136% increase over that of the neat soybean meal adhesive, and showed slightly higher bonding performance than the commercial urea-formaldehyde (UF) resin under boiling-water conditions. Structural analyses (FT-IR and XPS) verified quinone formation and carbon–nitrogen single and double bonds. Thermal analyses (DSC and TGA) revealed improved curing reactivity and significantly enhanced thermal stability compared with the neat soybean meal adhesive. Full article

Flame residence time (FRT) is an important indicator of flaming duration and is closely related to local heat release and associated ecological effects. However, the intrinsic mechanisms through which fuel bed structure affects FRT remains insufficiently understood. Clarifying how fuel bed structure affects FRT under flat, wind-free conditions is important for prescribed burning and ecological restoration. This study investigated surface fuels from typical forest types in southwestern China through controlled laboratory experiments conducted under flat, wind-free conditions, with moisture content, loading, thickness, and bulk density systematically varied. The driving mechanisms of fuel bed structural characteristics on FRT were systematically analyzed. Coniferous forests and moso bamboo had significantly lower FRT than broadleaved forests. Moisture content was the most influential factor, followed by thickness and bulk density, whereas loading had a relatively limited effect. Prediction models developed using machine learning methods significantly outperformed traditional regression approaches. Fuel bed structure is a critical factor controlling FRT. The high-accuracy prediction models established in this study enhance the mechanistic understanding of FRT. The findings provide a theoretical basis and practical support for prescribed burning and fire behavior modeling and may contribute to improved forest fire management. Full article

Laminated bamboo (LB) has emerged as a promising sustainable structural material due to its rapid renewability, high strength-to-weight ratio, and favorable mechanical performance. Drawing on a comprehensive review of over 90 published experimental and analytical studies, this paper provides a critical synthesis of the structural behavior of LB, with emphasis on its compression, tension, flexure, shear, and creep responses. Reported mechanical properties exhibit variability, largely influenced by bamboo species, fiber orientation, processing methods, adhesives, lamination quality, and loading configuration. While LB demonstrates high tensile and flexural strengths comparable to or exceeding conventional timber products, pronounced anisotropy and brittle failure modes are consistently observed, particularly under shear and rolling shear loading. Recent studies on cross-laminated bamboo (CLB) highlight the significant role of interlaminar behavior and adhesive performance in controlling failure mechanisms, indicating that rolling shear capacities often govern the design of planar elements. Beyond mechanical behavior, this review synthesizes available research on thermal and fire performance. Emerging research on LB connections indicates that joint behavior often governs global structural performance, with strength and ductility strongly influenced by fastener type and embedment behavior. Key knowledge gaps are identified, underscoring the need for unified design frameworks to enable broader structural adoption of laminated bamboo systems. Full article

Hard carbon (HC) was considered as a promising anode candidate for Na-ion batteries, due to its ability of efficient Na-ion storage. Bamboo-derived HC has the advantages of sustainability, environmental benefits and low cost, which are crucial for advancing the commercialization of SIBs technology. Precarbonization has been reported as a method to improve the electrochemical performance of HC anodes derived from various precursors, while the underlying mechanism behind why precarbonization improved the electrochemical performance of bamboo-derived HC has not been studied in detail. Herein, the effect of precarbonization on electrochemical behavior, bulk and surface structure, and surface composition was comprehensively explored. The results revealed that the improved reversible capacity was attributed to the increased closed pores for extra Na-ion storage, increased surface N content and decreased oxygen content for Na-ion absorption/desorption; the improved cycling stability was ascribed to the reduced surface oxygen and C-O content leading to suppressed side reactions, while the improved surface graphitization degree contributed to rate capability enhancement. This work clarified the role of precarbonization in improving the hard carbon anode for Na-ion batteries, which will be helpful to the commercialization of hard carbon materials. Full article

Accurately determining the thermal transmittance (U-value) of glazing systems plays a pivotal role in building energy conservation. This study establishes an explicit analytical model and conducts a systematic parametric analysis to elucidate the heat transfer mechanisms and key influencing factors governing the U-values of both single-pane and insulating glass. Based on fundamental thermodynamic principles and blackbody radiation laws, numerical iterative models are developed and validated against WINDOW and Fluent software simulations, with deviations consistently below 3.8%. A comprehensive parametric analysis quantifies the effects of glass thickness, cavity width, surface emissivity, and indoor/outdoor heat transfer coefficients. The results reveal that: (1) while U-values decrease approximately linearly with increasing glass thickness, they exhibit a non-monotonic relationship with cavity width, identifying an optimal cavity width of approximately 16 mm for air-filled insulating glass units; (2) surface emissivity exerts the most significant influence on the U-value, with cavity-facing surfaces demonstrating the greatest sensitivity (up to 81% variation), whereas outdoor surface emissivity shows negligible impact; (3) the U-value displays greater sensitivity to variations in the indoor heat transfer coefficient compared to outdoor conditions. Based on the parametric analysis under standard winter conditions, a preliminary design hierarchy is proposed for energy optimization: prioritize Low-E coatings on cavity surfaces, followed by cavity width optimization near 16 mm, and finally consider increasing glass thickness. The validated models and quantitative insights establish a benchmark calculation method for U-value analysis. These findings offer theoretical guidance and a prioritized optimization pathway for the preliminary design of energy-efficient glazing systems, particularly under standard winter conditions. Full article

This study assesses carbon footprint (CF) and explores mitigation potentials through improved resource efficiency for fire-resistant wood doors (WFDs) and fire-resistant bamboo doors (BFDs). Both WFDs and BFDs are certified to the Chinese national fire resistance standard GB 12955-2024, ensuring the same core fire resistance performance and functional equivalence. Results show that WFDs have a slightly lower CF (806.04 kg CO₂ e/m³) than BFDs (830.54 kg CO₂ e/m³), where the raw material phase acts as the main contributor (58.57–64.32%). Crucially, significant mitigation potentials are identified by enhancing resource efficiency across the product life cycle through reducing processing loss, and extending service lifespan, and sustainable recycling. Approximately 35.2 billion kg CO₂ will remain after reducing carbon loss by 5% in the Chinese wood/bamboo industrial sector. Recycling approaches (wood/bamboo panels, bio-based pellet fuel, and biochar) can be utilized with fewer emissions to economize bio-resources. The use of biochar provides greater carbon storage benefits and will help to limit the effects of climate change. Full article

The interfacial incompatibility and insufficient mechanical performance of polylactic acid (PLA)/cellulose composites have severely restricted their practical applications. To address the critical issue of interfacial incompatibility in PLA/cellulose composites, this work developed a novel strategy employing rosin emulsion for blending modification of microcrystalline cellulose (MCC), followed by a one-step extrusion process to fabricate PLA composites. The corresponding analyses confirmed that the rosin has been successfully added to MCC surfaces, forming the hydrophobic interface while maintaining the cellulose I crystalline structure. Subsequently, rosin emulsion-modified MCC (MCC-R) reinforced PLA (PLA/MCC-R) composites were fabricated via twin-screw extrusion at varying MCC-R contents. The testing results illustrated that the introduction of 8 wt% MCC-R can enhance the mechanical properties of PLA/MCC-R composites with the flexural strength (125.5 MPa), tensile strength (30.8 MPa), Young’s modulus (1.19 GPa), and elongation at break (3.07%), which was attributed to enhanced filler dispersion and interfacial stress transfer. Overall, this work established a facile and sustainable strategy for developing multifunctional PLA composites with engineered interfaces and mechanical robustness, which is vital for practical application. The as-prepared PLA composites show promising application prospects in environmentally friendly packaging, biodegradable disposable products, and lightweight structural components. Full article