Search Results (62)

Aiming to address the problems of shield chamber blockage and poor muck discharge faced by earth pressure balance shields during tunneling in sandy strata, bentonite slurry is used for muck improvement. Using a multi-scale approach combining macro-scale experiments, micro-scale analysis, and molecular dynamics simulations, this study systematically investigates the interface interactions between particles of sandy soil in shield tunneling and the improvement mechanism of sodium-based bentonite slurry additives. Through the macroscopic experiment, the sodium bentonite slurry soil–water ratio of 1:7 and injection ratio of 25% showed the best improvement effect. After improvement, the permeability coefficient decreased by 99.72%; the cohesion of the excavated soil increased from 3.055 kPa to 11.458 kPa, representing a 275.06% increase; and the angle of internal friction decreased from 42.318° to 36.985°, a decrease of 12.60%. The improvement was significant. Through SEM, XRD, and FTIR microanalysis, it is found that bentonite slurry forms a flexible film on the surface of sandy soil. By coating sand particles, filling voids in the soil, and enhancing interparticle cohesion, it improves the properties of the soil. On the nanoscale, a Na-MMT/SiO₂ system model is established based on molecular dynamics simulations to elucidate the interactions between bentonite slurry and sand particle interfaces. The results indicate the presence of van der Waals forces and hydrogen bonds between Na-MMT and SiO₂. Interlayer water molecules form a hydrogen bond network that strengthens interfacial bonding, enabling bentonite slurry to tightly adhere to soil particle surfaces. This improves the microstructure of the soil, thereby enhancing its macroscopic properties. Full article

The application of lignin-based films is often restricted by traditional processing methods that rely on toxic organic solvents and harsh chemical reagents, which result in poor compatibility with the polymer matrix and difficulty balancing transparency, barrier, and toughness. Here, lignin was green-modified by ternary deep eutectic solvent (choline chloride-lactic acid-ethanol), and ZnO hybrids with cellulose nanocrystals (CNC) as anchor points were introduced to realize the stability and uniform dispersion of ZnO in the polyvinyl alcohol (PVA) matrix. The prepared composite film maintains a transmittance of about 78% at 800 nm while achieving a wide spectrum of ultraviolet shielding. The barrier properties of the film were markedly improved: the water vapor permeability (WVP) decreased to 0.24 × 10⁻⁷ g·m⁻¹·h⁻¹·Pa⁻¹, and the oxygen permeability (OTR) to 6.98 cm³·m⁻²·24 h⁻¹·0.1 MPa⁻¹. In addition, the mechanical flexibility and durability of the material were significantly improved, as evidenced by a tensile strain of 109%. In the insurance experiment, compared with the blank film, the browning degree and weight loss of the composite film were relatively low. The scalable and low-solvent consumption route provides a practical idea for the application of lignin in food preservation. Full article

Wood coatings play a critical role in protecting wood substrates from environmental degradation, particularly ultraviolet (UV)-induced photodegradation. This review comprehensively examines the mechanisms of wood coating photodegradation, the factors influencing their durability, and current anti-aging strategies. Photodegradation arises from polymer chain scission, chemical structure reorganization, and photo-oxidation of lignin and cellulose, leading to coating chalking, cracking, gloss loss, and color changes, ultimately compromising wood mechanical properties and service life. Key anti-aging strategies include UV absorbers, which convert harmful UV radiation into heat; hindered amine light stabilizers (HALSs) that capture free radicals and quench excited-state molecules; barrier and shielding materials that form dense physical or nanostructured networks to block UV penetration and enhance mechanical and water resistance; and antioxidants that neutralize free radicals or decompose peroxides at the molecular level. Each approach can be employed individually or synergistically to enhance coating durability. Challenges remain in achieving long-term outdoor stability, balancing transparency and UV shielding, optimizing nanoparticle dispersion, and maintaining the activity of natural antioxidants. Future research should focus on multifunctional composite coatings integrating bio-based materials and nanotechnology, smart responsive systems, adaptive protection mechanisms, and standardized long-term evaluation protocols. These advancements will facilitate the development of high-performance, sustainable wood coatings and promote the value-added utilization of wood resources. Full article

Chitosan-based active films containing microwave-extracted Terminalia catappa leaf extract (TE) and hydrothermally synthesised zinc oxide were developed and characterised. The selected extraction condition (440 W, 20 min, followed by freeze drying) gave 29.5% extract recovery and a total phenolic content of 639.5 mg GAE/g extract. Structural analyses showed that the original crystalline ZnO phase was no longer detectable after film formation under acidic casting conditions, whereas zinc remained present in the film matrix, indicating acid-mediated dissolution and/or structural transformation during casting. Zinc-containing films exhibited higher tensile strength (up to 36.0 MPa), increased glass transition temperature (up to 122.9 °C), and reduced moisture content and water vapour transmission. TE contributed antioxidant activity and light-shielding properties, with antioxidant capacity reaching 22.1 mg Trolox/g film. Films containing ≥0.2% initial ZnO also showed disc-diffusion antimicrobial activity against Escherichia coli (up to 22.7 mm) and Staphylococcus aureus (up to 20.7 mm). A preliminary 7-day banana-wrapping study further suggested that intermediate formulations containing 0.1–0.2% TE and 0.2–0.3% initial ZnO provided a useful balance among mechanical performance, optical properties, antimicrobial activity, and visual preservation. Overall, zinc–polyphenol–chitosan interactions played an important role in governing film structure and functionality. Full article

The development of sustainable packaging materials with advanced functional properties is a key priority for the food industry. In this study, chitosan (CS)-based nanocomposite films incorporating titanium dioxide (TiO₂), zinc oxide (ZnO), hybrid ZnO_TiO₂ nanoparticles, lignin (LG), and nanolignin (nLG) were synthesized and comprehensively characterized. Structural analyses (FTIR, XRD, SEM) confirmed strong intermolecular interactions and homogeneous nanoparticle dispersion, particularly for TiO₂ and low ZnO concentrations. Mechanical testing showed that TiO₂ and ZnO significantly enhanced tensile strength (up to fourfold) and elongation at break. Among the prepared nanocomposite films, CS-TiO₂ films at 2 wt% exhibited the best balance of mechanical performance and antioxidant activity. Subsequent incorporation of LG and especially nLG into the CS-TiO₂ matrix further enhanced flexibility and toughness, antioxidant efficiency, and radical-scavenging activity above 90%, and improved UV-shielding capacity by reducing light transmittance. Moreover, antibacterial testing against Escherichia coli demonstrated that CS/TiO₂/nLG films achieved the highest reduction (~46%), attributed to synergistic electrostatic, oxidative, and phenolic mechanisms. Overall, CS/TiO₂/nLG nanocomposites emerge as multifunctional, biodegradable films with significant potential for next-generation active food packaging applications. Full article

During the construction of underwater shield tunnels (excavated using a slurry pressure balance shield machine), whether seawater (Sw) can be used to replace freshwater (Fw) in the preparation of cement–sodium silicate grout (CSG) has become a major concern in the engineering community. CSG is formed by mixing components A and B, where component A is a liquid prepared by mixing bentonite, cement, and water, and component B is a sodium silicate solution. In this paper, the CSG was prepared using Sw instead of part of Fw. The properties, including bleeding rate, initial and final setting time, gel time, compressive strength, and microscopic characteristics, were tested to investigate the influence of Sw on the performance of CSG and explore its impact mechanism. The results showed that when expanding bentonite with Sw, the bleeding rate of Component A exceeded 50%, failing to meet the engineering requirement of 10%. However, expanding bentonite with Fw, the seawater replacement ratio has almost no effect on Component A, with all values remaining below 10%. As the seawater replacement ratio increases, the setting time of CSG is significantly shortened. Although the inclusion of seawater results in a marginally lower 1-day strength for CSG, it notably boosts the strength at later ages. Specifically, at a 45% seawater replacement ratio, the 28-day strength showed a marked increase of 52% relative to the CSG without seawater. In the later stage of hydration, the positive effect of Cl⁻ in seawater, promoting the hydrolysis of C₃S and C₂S on strength, is significantly higher than the negative effect of sulfate ion erosion in seawater on strength. Therefore, seawater significantly increases the 28-day compressive strength of CSG. This study can provide reference and guidance for the application of seawater in the preparation of two-component grout for submarine shield tunnels. Full article

Background/Objectives: Unpredictable chronic mild stress exposure is a primary driver of cognitive decline, largely mediated by hypothalamic–pituitary–adrenal (HPA) axis dysregulation and subsequent oxidative neurotoxicity. In traditional Thai medicine, the AYW-KK-04 formulation—a complex polyherbal remedy—has long been utilized as a “Ya Aayu-Wattana” to restore vitality and elemental balance, yet its neurobiological mechanisms remain poorly understood. This study aimed to evaluate the adaptogenic and neuroprotective potential of AYW-KK-04 against cognitive impairment. Methods: Unpredictable Chronic Mild Stress (UCMS)-induced cognitive impairment in a ICR mouse model. Total phenolic and flavonoid contents and antioxidant capacity (ABTS assay) of AYW-KK-04 were determined. Behavioral assessments using Y-maze test, novel object recognition test (NORT), and Morris Water Maze (MWM) test. BDNF, CREB, Nrf and Keap1 mRNA gene expression, SOD and CAT enzymatic activity and lipid peroxidation assay were investigated to clarify the mechanisms of action. Moreover, HPLC chromatography was studied to quantify the active compounds of the AYW-KK-04 formulation. Results: It demonstrated that oral administration of AYW-KK-04 significantly reversed UCMS-induced memory deficits. At the molecular level, AYW-KK-04 effectively upregulated BDNF and CREB mRNA expression in the frontal cortex and hippocampus, suggesting a restoration of synaptic plasticity. Simultaneously, the formulation activated the Nrf2/Keap1 signaling pathway, leading to enhanced SOD and CAT enzymatic activities and a marked reduction in MDA-mediated lipid peroxidation. HPLC analysis confirmed the presence and consistency of key bioactive constituents. Conclusions: These findings suggest that the adaptogenic properties of AYW-KK-04 arise from its dual capacity to reinforce neurotrophic support and bolster the endogenous antioxidant shield, providing a mechanistic support for the traditional use of AYW-KK-04 as an adaptogenic formulation and highlighting its potential as a multi-target intervention for stress-related cognitive dysfunction. Full article

Traditional plastic preservation films face significant environmental challenges due to their non-degradable nature and limited functional versatility. In contrast, hydrocolloid–nanomaterial composite films—which integrate biopolymer matrices (e.g., cellulose, chitosan, alginate and gelatin) with nanoparticles such as SiO₂, Se, TiO₂, or ZnO—have emerged as a prominent research focus. These composite films preserve the inherent biodegradability and biocompatibility of hydrocolloids, while the nanomaterials, when stably dispersed, enhance interfacial interactions through electrostatic forces, hydrogen-bonding, or coordination bonds. This synergy endows the films with multifunctional properties, including antimicrobial activity, antioxidant capacity, UV-shielding performance, and stimuli-responsive intelligence. Prepared via techniques like electrospinning, solution casting, reactive extrusion, and coating, they exhibit excellent mechanical strength, barrier properties, and multifunctionality, effectively extending the shelf life of fruits, vegetables, meats, etc. However, challenges remain: nanomaterial dispersion, migration risks, and scalable production. This review summarizes recent advances to guide green preparation optimization, balance performance and safety, and advance sustainable development in food packaging. Full article

The present work develops an explicit dynamic finite element model of soil–disc interaction for a notched harrow disc, aiming to quantify how APS coatings, soil type and disc–soil friction influence stresses in the disc and surrounding soil. The model reproduces a four-gang offset harrow operating at 7 km/h, 0.15 m working depth, with 18°disc angle and 15° tilt angle, and compares an uncoated steel disc with three APS-coated variants (P1 Metco 71NS, P2 Metco 136F, P3 Metco 45C-NS). Mechanical properties of the substrate and coatings are obtained from micro-indentation tests and introduced via a bilinear steel model and Johnson–Cook plasticity for the coatings, while disc–soil friction coefficients are calibrated from microscratch measurements. Soil behaviour is described using the AUTODYN Granular model for four representative agricultural soils, spanning sandy loam to saturated heavy clay. Results show that the uncoated disc develops von Mises stresses in the disc–soil contact region of ≈150–220 MPa, with intermediate-stiffness soils being most critical. APS coatings significantly alter both the level and distribution of stresses: P2, the stiffest ceramic, yields the highest stresses (≈421–448 MPa), P1 keeps stresses near the baseline while shielding the substrate through extended plastic zones, and P3 provides an intermediate, more uniformly distributed stress regime. Increasing disc–soil friction systematically amplifies von Mises stresses in the contact region, especially for P2. Overall, the calibrated explicit model captures the coupled influence of soil properties, coating stiffness and friction, and indicates that P1 is better suited for light-to-medium soils, P3 offers the most balanced response in medium-to-stiff soils, whereas P2 should be reserved for highly abrasive conditions and used with caution in cohesive soils. Full article

Sodium alginate (SA) is widely used as an edible coating for fruit preservation, but its weak water barrier and antibacterial properties limit broader application. In this study, quaternary ammonium lignin–cinnamaldehyde (QKC) composite particles were incorporated into SA as multifunctional fillers to construct antibacterial coatings. Electrostatic and hydrogen-bonding interactions between cationic QKC and anionic SA yielded a uniform, stable network with improved hydrophobicity and UV-shielding capacity. At 5 wt% QKC loading (SA5), the tensile strength increased from 11.53 to 24.42 MPa (111.8% higher than SA0), while water vapor permeability decreased by 35.4%. SA coatings also exhibited strong antioxidant activity, and the ABTS radical scavenging rate increased to 70.22% at 7 wt% QKC, with SA5 offering a favorable balance between antioxidant, barrier, and mechanical properties. SA5 showed pronounced antibacterial efficacy, giving inhibition rates of 96% against Staphylococcus aureus and 65% against Escherichia coli. Coating trials on persimmons and tangerines demonstrated that SA5 reduced weight loss, delayed firmness decline, and mitigated decay during storage. In addition, calcium-crosslinked SA/QKC hydrogel beads markedly delayed visible mold growth on blueberries. These results indicate that QKC-reinforced SA coatings provide a promising strategy for enhancing the postharvest quality and shelf life of fresh fruit. Full article

Hybrid buckypapers (BPs) composed of graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) hold great potential for applications in flexible electronics, electromagnetic shielding, and energy storage. In this study, hybrid BPs were fabricated and characterized to evaluate their structural, thermal, and electrical properties. Hybrid BPs with varying GNP/CNT mass ratios (0/100, 25/75, 50/50, 75/25, 85/15, 90/10, and 95/5 wt%) were prepared via vacuum-assisted filtration of well-dispersed aqueous suspensions stabilized by surfactants. The resulting hybrid GNP/CNT BPs were dried and subjected to post-treatment processes to enhance structural integrity and electrical performance. Characterization techniques included scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Raman spectroscopy, thermogravimetric analysis (TGA), nitrogen adsorption/desorption isotherms, and impedance spectroscopy (IS). The hybrid GNP/CNT BPs exhibited electrical conductivities comparable to conventional CNT-based BPs. At GNP concentrations of 25 to 50 wt%, electrical conductivity values approached those of CNT-based BPs, while at GNP concentrations between 75 and 90 wt%, a slight increase in conductivity was observed (171%). These results highlight a synergistic effect at lower CNT concentrations, where the combination of CNTs and GNPs enhances conductivity. The findings suggest that optimal conductivity is achieved through a balanced incorporation of both materials, offering promising prospects for advanced BP applications. Full article

The remarkable growth of high-frequency electronic systems has raised concerns about electromagnetic interference (EMI), emphasizing the need for lightweight and efficient shielding materials. In this study, ternary composites based on polypyrrole (PPy), graphene oxide (GO), and silver nanowires (AgNWs) were synthesized through chemical oxidative polymerization of pyrrole monomer and embedded into polycaprolactone (PCL) matrices to create flexible films. Structural and morphological analyses confirmed the successful incorporation of all components, with scanning electron microscopy showing granular PPy, sheet-like GO, and fibrous AgNWs, while spectroscopic studies indicated strong interfacial interactions without damaging the PPy backbone. Thermomechanical analysis revealed that GO increased stiffness and defined the glass transition, whereas AgNWs improved toughness and energy dissipation; their combined use resulted in balanced properties. EMI shielding effectiveness (SE) was tested in the X-band (8–12 GHz). Pure PPy exhibited poor shielding ability, while the addition of GO and AgNWs significantly enhanced performance. The highest EMI SE values were observed in PPy/GO–AgNWs composites, with an average SE of 16.05 dB at 20 wt% of the composite in the PCL matrix, equivalent to about 84.4% attenuation of incident waves. These results demonstrate that the synergistic integration of GO and AgNWs into PPy matrices enables the creation of lightweight, flexible films with advanced EMI shielding properties, showing great potential for next-generation electronic and aerospace applications. Full article

This study developed a waterborne UV-curable acrylic composite coating incorporated with carved lacquer powder and systematically investigated the effects of powder and deionized water content on its properties. The results showed that the carved lacquer powder content significantly influenced the optical, mechanical, and curing behaviors of the coating, while the water content had negligible impact. Specifically, increasing the powder content reduced lightness, enhanced red hue, and decreased gloss. An optimal comprehensive performance was achieved at 20% powder content, with adhesion reaching grade 5, flexibility of 10 mm, and impact resistance of 6 kg·cm. FTIR analysis confirmed that high powder content (≥20%) led to incomplete curing due to UV shielding. The coatings showed moderate resistance to water, acid, and saline environments but poor alkaline resistance due to the chemical instability of cinnabar. SEM revealed increased surface roughness at high powder loading (30%). More importantly, this work presents a sustainable approach to recycle carved lacquer waste and demonstrates a viable strategy for incorporating traditional cultural heritage materials into advanced functional coatings. The study demonstrates that carved lacquer powder can be effectively integrated into UV-curable coatings to achieve unique decorative effects, and a content of approximately 20% is recommended to achieve balanced properties. Full article

This study investigates the fabrication of a Cu-Mn-Al alloy coating on 27SiMn steel using Cold Metal Transfer (CMT) technology with an innovative Ar-B(OCH₃)₃ mixed shielding gas, focusing on the effect of the gas flow rate (5–20 L/min). The addition of B(OCH₃)₃ was found to significantly enhance process stability by improving molten pool wettability, resulting in a wider cladding layer (6.565 mm) and smaller wetting angles compared to pure Ar. Macro-morphology analysis identified 10 L/min as the optimal flow rate for achieving a uniform and defect-free coating, while deviations led to oxidation (at low flow) or spatter and turbulence (at high flow). Microstructural characterization revealed that the flow rate critically governs phase evolution, with the primary κI phase transforming from dendritic/granular to petal-like/rod-like morphologies. At higher flow rates (≥15 L/min), increased stirring promoted Fe dilution from the substrate, leading to the formation of Fe-rich intermetallic compounds and distinct spherical Fe phases. Consequently, the cladding layer obtained at 10 L/min exhibited balanced and superior properties, achieving a maximum shear strength of 303.22 MPa and optimal corrosion resistance with a minimum corrosion rate of 0.02935 mm/y. All shear fractures occurred within the cladding layer, demonstrating superior interfacial bonding strength and ductile fracture characteristics. This work provides a systematic guideline for optimizing shielding gas parameters in the CMT cladding of high-performance Cu-Mn-Al alloy coatings. Full article

Earth Pressure Balance (EPB) shield machines have been widely used in subway construction due to their versatility and safety. During the shield tunneling process, the earth pressure in the shield machine chamber is crucial for controlling ground settlement and ensuring the safety of surrounding buildings. However, current research on the temporal and spatial evolution of earth pressure in water-rich sand layers and its relationship with ground settlement is relatively insufficient. This study focuses on the shield tunneling project between Liuzhou East Road and Puzhou Road on Nanjing Metro Line 11. First, laboratory and on-site tests were conducted to optimize the slump properties of the sediment. Then, based on Terzaghi’s theory and statistical methods, the temporal and spatial evolution trends of the earth pressure in the shield chamber under water-rich sand conditions were explored. Finally, by adjusting earth pressure control parameters on-site and monitoring ground settlement, the impact of earth pressure changes on ground settlement was analyzed. Results showed a linear correlation between the actual earth pressure and shield burial depth. For water-rich sand with medium permeability, the theoretical earth pressure was calculated using Terzaghi’s water-soil combined method in shallow sections, and the average of combined and separated methods in deep sections. The decay envelope showed an exponential downward trend, with rapid decay initially and slower decay later. As earth pressure control values increased, pre-consolidation settlement increased, instantaneous settlement decreased, pre-consolidation settlement rate slightly increased, and instantaneous settlement rate decreased. When excavation pressure was below theoretical pressure, higher instantaneous settlement rates could threaten surface structures. This research offers vital theoretical and data references for shield tunneling in water-rich sand layers and supports related EPB shield machine theory studies. Full article