Search Results (402)

Rosin- and castor-oil-derived resins provide a renewable platform for rapidly curable protective coatings, but the effects of formulation and curing route remain insufficiently resolved. Four composite formulations containing modified rosin glycerol ester (MRGE) and modified castor oil anhydride (MCOA) were cured thermally using ultraviolet irradiation or electron beam (EB) irradiation. Surface C=C conversion, thermal behavior, morphology, mechanical properties, neutral salt spray resistance, electrochemical barrier performance, and AC dielectric breakdown strength were evaluated. Among the formulations tested, F2 (MRGE/MCOA = 3:1) showed the best overall property balance under each curing route. For F2, EB curing produced a surface C=C conversion of 92 ± 2%, a glass transition temperature of 88 ± 1 °C, an 800 °C residue of 12.5 ± 0.3%, and an atomic force microscope (AFM) roughness Ra of 5.8 ± 0.5 nm. F2-EB exhibited 9H pencil hardness, 5B adhesion, an impact resistance of 55 ± 2 cm·kg, and a flexibility value of 1.0 ± 0.1 mm. After 500 h of neutral salt spray, both F2-EB and F2-UV achieved a protection rating of 10 with no measurable corrosion creep at the scribe; time-resolved photographs at 100, 300, and 500 h confirmed that F2-EB showed the least visible damage evolution among the three curing routes. After 1 day of immersion in 3.5 wt% NaCl, F2-EB exhibited the largest low-frequency impedance and the lowest fitted corrosion current density among the EB-cured formulations, indicating the strongest short-term electrolyte barrier behavior. The AC dielectric breakdown strength of F2-EB reached 21.5 ± 0.3 kV mm⁻¹. The combined results are consistent with more extensive EB-induced network formation, although direct measurements of through-thickness conversion and crosslink density are still required. These findings demonstrate the potential of EB curing for rapidly preparing rosin/castor-oil-derived protective coatings for electrical insulation applications. Full article

Fly ash (FA) recycling into cementitious binders offers a promising route to simultaneously reduce the environmental burden of high-impact construction materials, divert industrial waste from disposal pathways, and generate engineering value from an existing aluminosilicate residue. FA has therefore been widely incorporated into ordinary Portland cement (OPC), calcium sulfoaluminate (CSA) cement, magnesium potassium phosphate cement (MKPC), and alkali-activated/geopolymer systems, where it can improve workability, mechanical strength, durability and promote hydration reactions, depending on the binder chemistry. However, these benefits are not always successful: FA addition may also reduce early-age strength, delay setting, limit reactivity, impair fluidity, or produce under-reacted matrices when ash properties are mismatched with the chemistry window of the target binder. Rather than revisiting these systems as isolated application categories, this review develops a property-guided framework for interpreting and selecting FA across major cementitious routes. It first highlights why FA should not be treated as a single material. Key descriptors include glass content, fineness, calcium level, carbon residue, mineralogy, and beneficiation state. The review then compares four representative binder environments to clarify the role of FA shifts from pozzolanic contributor to filler-dominated hydration modifier to functional regulator, and finally to reactive precursor, including the calcium hydroxide (CH)-rich Portland systems, CH-poor CSA systems, phosphate-bonded MKPC systems, and alkali-activated/geopolymer systems. The central conclusion is that the key question is not simply where FA can be used, but which FA is best matched with which binder chemistry and for what performance objective. Full article

Problematic subgrade soils degrade pavement performance, while conventional cement/lime stabilizers generate excessive carbon emissions. Unlike earlier reviews that focus on single-material systems—such as industrial by-products, alkali-activated binders for expansive soils, or geopolymers for pavement applications—an integrated framework spanning reaction mechanisms, microstructural evolution, engineering parameterization, and life-cycle validation is proposed The work offers three distinctive contributions: (i) a four-level evidence chain hierarchy (strength → microstructure → durability → leaching/LCA) to grade research completeness; (ii) repositioning resilient modulus, permanent deformation, and pore-connectivity evolution as core engineering outputs bridging material design and structural response; and (iii) a comparative assessment of alkali-activated geopolymers, low-clinker calcium-based composites, and multi-scale reinforcement strategies under consistent durability and environmental boundaries. Quantitative synthesis reveals the following: strength retention after 12 wet–dry/freeze–thaw cycles ranges from 60% to 85%; resilient modulus improvements over untreated soils reach 30%–120%, yet stress-dependent characterization remains essential; leaching concentrations of hazardous elements (Cr, Ba, Pb) can increase by 50%–200% after durability cycling if pore connectivity rebounds. Life-cycle carbon comparisons are boundary-sensitive—geopolymer advantages shrink from 60% to ≤20% when activator transport and pre-treatment are included. We conclude that the primary barrier to engineering adoption is not the absence of high-strength formulations, but the lack of extrapolatable design parameters and closed-loop evidence chains. A decision-support framework incorporating durability retention, leaching safety, carbon footprint, and field validation is proposed to guide robust design and industrial scaling. Critically, the review identifies that engineering adoption is constrained not by the absence of high-strength formulations, but by the lack of standardized construction protocols, quality control procedures, and long-term field performance data—gaps that must be addressed through coordinated field-scale demonstration projects. Full article

The electrochemical performance of eight commercially available bioelectrodes for electrophysiological measurements was systematically evaluated in isotonic saline solution. The studied bioelectrodes included sintered Ag/AgCl pellet, cup and ring, an Ag/AgCl multipin, tin (Sn) ring and disc, a gold cup, and a stainless-steel needle. Open circuit potential (OCP) and drift rate, electrochemical impedance spectroscopy (EIS), and electrochemical noise (ECN) measurements were performed to assess interfacial stability, impedance behavior, and generated noise in time and frequency domains. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) were used to study the morphology and chemical composition of the bioelectrodes. Ag/AgCl-based bioelectrodes exhibited the highest OCP stability and potential reproducibility, lowest impedance, and electrochemical noise, attributed to the fast and reversible Ag/AgCl electrochemical equilibrium, and high area related to roughness and porosity. EIS analysis showed predominantly low-resistance charge-transfer behavior and high capacitance for Ag/AgCl bioelectrodes, while tin, gold, and stainless-steel bioelectrodes displayed higher impedance and mixed capacitive/resistive responses associated with passive oxide films and slower interfacial kinetics. Tin, gold, and stainless-steel bioelectrodes also presented substantially higher low-frequency noise and OCP drift rate. Among all tested bioelectrodes, sintered Ag/AgCl bioelectrodes demonstrated the most favorable electrochemical characteristics for electrophysiological signal acquisition, particularly for low-amplitude and low-frequency biosignals. Full article

Chinese lacquerware is valued for its distinctive gloss, hardness, and durability. In this study, three layers of natural lacquer were applied to 3D-printed PLA substrates and exposed to UVA-340 accelerated aging for 25 days. The lacquer film gradually became lighter in color, with the lightness value increasing from 30.69 to 44.69. At the same time, gloss decreased from 59.37 to 48.28 GU, while surface roughness increased significantly, with Ra rising from 2.11 to 10.07 μm. Pencil hardness declined from H to 5B, indicating a reduction in surface strength. FTIR results showed partial oxidation of phenolic hydroxyl groups, whereas the aromatic backbone and aliphatic side chains remained largely unchanged. These results suggest that UV aging mainly causes surface photo-oxidation, leading to fading, gloss loss, roughening, and reduced durability of the lacquer coating. SEM images showed that the lacquer surface changed gradually during UV exposure. In the first few days of aging, small cracks started to appear on the surface, along with a bit of powdering. As UV exposure continued, the cracks gradually became larger and began to spread. By the final stage, many of them linked up into a network, but the overall damage slowed down compared to earlier stages. Overall, the process moved through a quick initial change, then a period of crack growth, and finally a more stable phase. These results help make it clearer how UV light affects lacquer coatings on polymer-based materials. Full article

Conventional epoxy adhesives used in motor insulation structures still suffer from insufficient thermal resistance and difficulty in balancing heat resistance with mechanical reliability. In this study, BMI-modified E-51/MeHHPA/EMI-24 epoxy composites were prepared and evaluated as heat-resistant interfacial adhesives for simulated F-class pole windings. BMI/EP composites with different BMI contents were fabricated by melt blending and characterized in terms of curing kinetics, FTIR, mechanical properties, and thermal performance. The optimized formulation was then applied to bond Nomex insulation paper to the upright plate in a simulated pole winding. The results showed that BMI did not alter the main epoxy/anhydride curing pathway, but restricted segmental motion and improved thermal resistance. The 10phr BMI/EP composite exhibited a favorable balance among thermal performance, mechanical properties, and fracture morphology. The simulated winding prepared with this formulation showed no breakdown or flashover under 6800 V/60 s, with an insulation resistance of 64.49 GΩ. A lower-bound apparent temperature index of approximately 157 °C was obtained using the TGA-derived thermal life equation. These results indicate that this system has preliminary application potential as a heat-resistant interfacial adhesive for F-class motor winding insulation, although a complete thermal life assessment is still required. Full article

Driven by the high-end furniture industry’s demand for skin-tactile decorative boards, UV inkjet printing shows potential for wood-based surface finishing. Using primer-treated inkjet-printed melamine-faced panels, this study compared traditional UV varnish coatings with different thicknesses and UV curing intensities and 254 nm UV excimer-cured coatings with different radiant energies. Varnish thickness significantly affected surface roughness, 20° gloss, 85° gloss, and color difference, indicating a trade-off between matte tactile appearance and color fidelity. Thinner varnish coatings exhibited higher roughness and lower gloss but larger color differences, whereas thicker coatings better preserved color fidelity but resulted in higher gloss. For the UV excimer-cured system, one-way ANOVA showed significant treatment effects on acrylate conversion, water contact angle, 85° gloss, surface roughness, and abrasion mass loss. The coating prepared at an excimer radiant energy of 827.9 mJ/cm² showed the lowest 85° gloss of 5.28 GU and a pencil hardness of 3H, but also exhibited the highest abrasion mass loss in the short-cycle abrasion screening test. For both coating systems, three independently prepared specimens were tested for each processing condition. The UV varnish system was analyzed using two-way ANOVA, whereas the UV excimer-cured system was analyzed using one-way ANOVA. Friedman tests of sensory evaluation data showed significant differences among the eight selected samples for fineness, smoothness, and elasticity, with the excimer-cured coatings generally receiving higher fineness and smoothness scores than the UV varnish coatings. These results indicate that 254 nm UV excimer curing is a promising route for producing low-gloss, micro-wrinkle-induced skin-tactile surfaces on inkjet-printed melamine-faced panels, although optimization should balance tactile quality, gloss reduction, and abrasion resistance. Full article

Under low-temperature and humid conditions, icing on airfoil surfaces, such as wind turbine blades, deteriorates the aerodynamic performance and decreases the power generation efficiency. To shorten the de-icing time and reduce the de-icing energy consumption, an ultrasonic de-icing method was used by coupling the longitudinal vibration of a piezoelectric transducer and the bending deformation of an iced plate. The simulation method was used to investigate the distributions and the variations of the stresses at the bond interface. An experimental system for ultrasonic de-icing tests was developed and built, and the de-icing experiments were carried out. The experimental results showed that the present ultrasonic de-icing method had a short de-icing time and low de-icing energy consumption, and the de-icing processes agreed with the simulation results. In the present research, the ice layer with a diameter of 20 mm was removed in the shortest de-icing time and the lowest energy consumption because its diameter was close to that of the transducer, which resulted in the highest shear stress at the bond interface. The present study provides theoretical and experimental foundations for deep research on the surface anti- and de-icing method with ultrasonic techniques. Full article

Near-fault pulse-like ground motions (NFPLGMs) impose concentrated energy demands that can severely damage bridges, yet their scarcity and the influence of structural parameter uncertainties are often neglected in seismic fragility assessments. This study proposed a synthesis method for NFPLGMs by superposing low-frequency pulse components (extracted via the Gabor wavelet transform and low-pass filtering) with high-frequency stochastic components based on an evolutionary power spectrum. A three-span reinforced concrete bridge was modeled in OpenSeesPy, and Incremental Dynamic Analysis (IDA), together with a quadratic response surface model, were used to plot seismic fragility curves. The damping ratio (ξ), elastic modulus of steel reinforcement (E_s), yield strength of steel reinforcement (f_y), diameter of longitudinal reinforcement (D), and peak ground acceleration (PGA) were treated as random variables. Sensitivity indices were computed using Monte Carlo sampling (n = 10,000). Results show that ξ most strongly affects the displacement ductility ratio of the bridge pier (u_d) (variation of up to 32.6%), while E_s dominates the shear deformation of the bridge bearing (d) (variation of up to 43.8%). Neglecting structural parameter uncertainties overestimates median PGA thresholds (m_R) for different damage states by 1.5%–36.1%, and replacing NFPLGMs with ordinary ground motions overestimates seismic capacity by 1.7%–36.6%. The bridge bearing is consistently more vulnerable than the pier, with a collapse probability of 0.9566 at PGA = 1.0 g. These findings highlight the necessity of incorporating both NFPLGM characteristics and structural parameter uncertainties into bridge seismic fragility assessment. On the other hand, when seismic retrofitting of bridges is carried out using coating materials, priority should be given to more vulnerable components, such as bridge bearings, to improve the utilization efficiency of limited resources. Full article

Superhydrophobic materials offer promising prospects for utilization in energy, environmental, and related fields. However, their long-term stability in natural environments is constrained by factors such as mechanical wear and aging, which compromise their practical effectiveness and service life. While notable experimental results have been obtained worldwide, scalable application remains limited by the complexity of the requisite fabrication processes. In this study, a durable superhydrophobic coating was developed through a facile one-step process, utilizing a polyaspartic ester (PAE) matrix reinforced with a composite of self-synthesized fluorinated silica (F-SiO₂) and hexagonal boron nitride (h-BN) micro-/nano-structures. This strategy effectively enhanced filler dispersion within the resin matrix and promoted hydrophobicity, yielding a stable superhydrophobic surface. The resulting coating exhibits significant potential for scalable application. The optimized coating demonstrated a water contact angle of 161.2° and a roll-off angle of 7.6°, showing excellent repellency to water, corrosive liquids, and fluids across a wide pH range, along with remarkable self-cleaning performance. Benefiting from the synergistic enhancement of h-BN and F-SiO₂, the coating also exhibits superior mechanical durability, maintaining a contact angle of 144.4° after 1000 abrasion cycles. Furthermore, in low-temperature anti-icing tests, the coating significantly delayed ice formation on its surface. Notably, after 1000 h of UV aging tests, the F-SiO₂@BN/PAE coating retained its intact superhydrophobic structure, with the water contact angle only slightly decreasing from 159.6° to 152.8°, still within an excellent superhydrophobic state, demonstrating outstanding weather resistance. By integrating surface functionalization with mechanical reliability through a facile one-step fabrication process, this study provides significant insights for the large-scale application of hydrophobic materials in the energy and transportation sectors. Full article

Zinc oxide (ZnO) nanoparticles have attracted increasing attention in wood science due to their multifunctional properties, including antimicrobial activity, UV absorption, and photocatalytic behavior. Water-based deposition protocols offer clear advantages yet typically struggle with nanoparticle aggregation and limited adhesion to lignocellulosic substrates. This work introduces a rapid and scalable waterborne protocol combining catalyst-free aqueous seeding with microwave-assisted (MWA) growth under mild conditions. Pinus pinaster veneer samples were treated via dip-coating and spraying, with single and double seeding cycles, followed by MWA growth. Protocol efficiency was assessed through ZnO retention, SEM, and EDS analysis, while the impact of the substrate was assessed via mechanical testing, ATR-FTIR spectroscopy, and colorimetry. Dip-coating achieves significantly higher precursor uptake than spraying, while repeated seeding cycles further increase ZnO loading. Results suggest that incorporation may proceed through zinc–carboxylate bonds within the wood matrix, followed by localized ZnO nanostructures development. The effective integration did not weaken the mechanical properties, while color changes were significant for dip-coated samples and noticeable for sprayed ones. Overall, this methodology provides a fast, water-based, and minimally invasive route for ZnO incorporation into wood and a scalable pathway with retained mechanical and chemical properties and limited visual impact. Full article

Silver nanowire (AgNW) networks have attracted significant attention as leading candidates for flexible transparent electrodes owing to their unique combination of high electrical conductivity, optical transparency, and mechanical compliance. This review presents an overview of recent developments in AgNW-based transparent electrode technologies, with particular emphasis on strategies to improve network conductivity and long-term reliability, including junction engineering, surface modification, encapsulation approaches, and composite structure design. Representative applications in flexible optoelectronic systems, such as organic light-emitting devices, transparent heating elements, and electrochromic platforms, are also discussed. Finally, current challenges and future research directions toward scalable manufacturing and practical implementation of high-performance AgNW electrodes are outlined. Full article

Polyester (PET) fibers are widely used to reinforce asphalt materials; however, their smooth and hydrophobic surfaces limit interfacial bonding and restrict their reinforcing efficiency. This study develops an eco-friendly surface modification method based on the chemical modification of gallic acid (GA) and aminosilane (KH792) to enhance the compatibility between PET fibers and asphalt. Modified fibers with various molar ratios of GA/KH792 were prepared and incorporated into asphalt mastic. Their performance was evaluated using softening point, cone penetration, dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), linear amplitude sweep (LAS), and bending beam rheometer (BBR) tests, combined with interfacial interaction analysis and scanning electron microscopy (SEM). The results show that surface modification significantly improves the reinforcing effect of PET fibers. In particular, the co-modified fiber with a GA/KH792 ratio of 1:1 exhibits the best performance, with increases of 27% in softening point and 105% in shear strength, as well as notable improvements in rutting resistance, fatigue performance, and temperature stability. Interfacial indices and SEM observations confirm enhanced adhesion, dispersion, and load transfer capacity. However, the improvement in low-temperature performance is limited. Overall, GA/KH792 chemical modification effectively enhances fiber asphalt interfacial interaction and provides a simple and sustainable approach for developing high-performance asphalt materials. Full article

Sulfate attack is a major cause of deterioration in tunnel lining concrete under aggressive underground conditions. This study investigates the sulfate resistance of fiber-reinforced ferroaluminate cement concrete incorporating steel slag powder through combined experimental and numerical approaches. Specimens with different fiber contents (0, 0.2%, and 0.4%) were subjected to dry–wet cycles in a 5% sodium sulfate solution. The results show that fiber incorporation significantly enhances sulfate resistance, with the optimal performance achieved at 0.2% fiber content. Compared with ordinary Portland cement concrete, ferroaluminate cement-based concrete exhibits improved durability, including lower mass variation, reduced strength degradation, and more stable dynamic elastic modulus. Microstructural analyses indicate that hydration products refine the pore structure, while fibers effectively inhibit crack propagation and expansion damage. Numerical simulation of tunnel lining structures further demonstrates that the optimized material reduces stress concentration, displacement, and crack development. Overall, the proposed material shows superior performance and promising application potential for tunnel linings in sulfate-rich environments. Full article

To enhance flame retardancy of waterborne polyurethane (WPU) coatings, this paper proposes a co-modification method using modified graphene oxide (SiO₂@GO) and a phosphorus flame retardant (P-). SiO₂@GO refers to graphene oxide (GO) with an attached silicon dioxide (SiO₂) layer, while the phosphorus flame retardant (P-) in this work is THPO, a reactive flame retardant used as a chain extender. The influence of component additions on flame retardancy was systematically investigated. Modified WPU coatings (P-SiO₂@GO/WPU) were prepared using THPO and SiO₂@GO as flame-retardant chain extenders. The morphology, structure, and thermal stability of P-SiO₂@GO/WPU were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). At 2% SiO₂@GO, coatings showed enhanced hydrophobicity (water repellency) and thermal stability. With 4% phosphorus flame retardant (P-), the limiting oxygen index (LOI, a measure of flame retardancy) reached 32.2%, and the heat release rate was 32.4% lower than before modification. A continuous, dense P/Si-containing carbonaceous ceramic-like barrier layer was formed, effectively blocking the release of combustible gases and the transfer of heat, thereby demonstrating excellent flame retardancy. This synergistic P-SiO₂@GO/WPU modification offers theoretical support and practical guidance for optimizing and enhancing the flame-retardant performance of WPU coatings. Full article