Search Results (297)

This study conducts systematic experimental and numerical investigations to address the parameter calibration issue in the discrete element model of seashells, aiming to establish a high-fidelity numerical model that accurately characterizes their macroscopic mechanical behavior, thereby providing a basis for optimizing parameters of seashell crushing equipment. Firstly, intrinsic parameters of seashells were determined through physical experiments: density of 2.2 kg/m³, Poisson’s ratio of 0.26, shear modulus of 1.57 × 10⁸ Pa, and elastic modulus of 6.5 × 10¹⁰ Pa. Subsequently, contact parameters between seashells and between seashells and 304 stainless steel, including static friction coefficient, rolling friction coefficient, and coefficient of restitution, were obtained via the inclined plane method and impact tests. The reliability of these contact parameters was validated by the angle of repose test, with a relative error of 5.1% between simulation and measured results. Based on this, using ultimate load as the response indicator, the PlackettBurman experimental design was employed to identify normal stiffness per unit area and tangential stiffness per unit area as the primary influencing parameters. The Bonding model parameters were then precisely calibrated through the steepest ascent test and design, resulting in an optimal parameter set. The error between simulation results and physical experiments was only 3.8%, demonstrating the high reliability and accuracy of the established model and parameter calibration methodology. Full article

This study presents an integrated, cost-aware artificial intelligence (AI) meta-modelling framework for mine-to-mill optimisation that couples high-fidelity simulation with data-driven predictive modelling. Using over three million scenarios generated in the Integrated Extraction Simulator (IES), the framework quantifies how upstream design parameters such as burden, spacing, hole diameter, and explosive density propagate through screening, crushing, stockpiling, and grinding to affect downstream costs and throughput. Random Forest-based meta-models achieved predictive accuracies above 90%, enabling the rapid evaluation of technical and financial trade-offs across the mining value chain. Stage-wise cost models were formulated for drilling, blasting, comminution, and material handling to link process variables to costs per tonne. The results reveal clear non-linear cost responses: finer fragmentation reduces the total comminution cost despite higher explosive expenditure, while SAG mill load and speed exhibit U-shaped cost relationships with distinct optimal operating windows. By combining physics-based simulations, machine learning, and cost integration, the framework transforms traditional stage-wise optimisation into a holistic, financially informed decision-support system. The proposed methodology supports real-time, AI-enabled digital twins capable of adaptive mine-to-mill optimisation, paving the way for more efficient and sustainable resource extraction. Full article

To address the inefficiency and high labor intensity associated with traditional manual mussel seedling unloading, this study proposes an automated traction-rope mussel unloading machine. This study focuses on the thick-shelled mussel (Mytilus coruscus) as the research subject. Furthermore, the key mussel unloading processes were simulated using the EDEM software to analyze mechanical interactions during detachment. A breakable mussel discrete element model was developed, and its Bonding V2 model parameters were systematically calibrated. Using the ultimate crushing displacement (2.25 mm) and ultimate crushing load (552 N) as response variables, the model was optimized through a sequential experimental design comprising Plackett–Burman screening, the steepest ascent method, and the Box–Behnken response surface methodology. The results demonstrate that the optimal parameter combination consists of unit area normal stiffness (2.48 × 10¹¹ N/m³), unit area tangential stiffness (3.80 × 10⁸ N/m³), critical normal stress (3.15 × 10⁶ Pa), critical tangential stress (2.90 × 10⁷ Pa), and the contact radius (1.60 mm). The model’s accuracy was validated through integrated discrete element simulations and prototype testing. The equipment achieves an exceptionally low mussel damage rate of only 1.2%, effectively meeting the operational requirements for mussel unloading. This study provides both theoretical foundations and practical insights for the design of mechanized mussel unloading systems in China. Full article

High-speed train derailments can cause severe vehicle collisions with rail bridges and adjacent infrastructure; however, full-scale evidence for the collision response of trackside intrusion-protection walls and for material measures that limit concrete fragmentation remains scarce. This study addresses this safety-driven knowledge gap by reporting a full-scale collision test of a polyurea-coated reinforced concrete (RC) wall and by clarifying its governing response mechanisms and coating benefits. The inverted T-shaped RC wall was post-anchored to an existing deck and spray-coated with approximately 5 mm polyurea on the collision face and across the wall-footing junction. A 17.68 t container wagon was propelled to 34.59 km/h to reproduce the normal kinetic energy of a representative 68 t KTX car derailing at 300 km/h with a 3° collision angle. High-speed video tracking and post-test mapping captured displacements, rotations, and damage. The wall contained the container wagon without climb-over and without severe local crushing at the collision face; the response was dominated by stable wall-footing rocking, with a peak top displacement of 0.571 m, peak rotation of 19.9°, and residual inclination of approximately 15–17°. The peak collision-force estimate was approximately 1.17 MN, and most input energy (approximately 647–816 kJ) was dissipated through inelastic rocking and sliding while the anchors remained intact. The polyurea layer restrained spalling and fragment release and promoted a more global, repairable rocking-dominated damage state. These results provide rare full-scale benchmarks and mechanistic insight to support performance-based design and retrofit of derailment intrusion-protection walls for improved rail-bridge safety. Full article

Food packaging is the largest segment of the global plastics market, yet its low degradability and limited performance in preserving perishable goods highlight the need for more sustainable alternatives. This study investigates the use of industrial softwood kraft lignin, a renewable polyol, and γ-valerolactone (GVL), an excellent green lignin solvent, to synthesize bio-based polyurethane (PU) coatings for recycled linerboard. PU was synthesized with hexamethylene diisocyanate (HDI), GVL, and 1,4-diazabicyclo[2.2.2]octane (DABCO) as a catalyst and applied to recycled linerboard (166.6 g/m²) at three coating weights: 13.5, 16.5, and 23.5 g/m². The coating enhanced water resistance, as shown by the reduced water vapor transmission rate (WVTR) and Cobb₁₈₀₀ values. Oil resistance was also significantly improved, reaching a Kit rating of 11 at the highest coating weight. Mechanical performance was maintained or enhanced, with increases in ring crush strength (RCT) and tensile index. These findings confirm the effectiveness of lignin-based PU in improving both the barrier and mechanical properties of packaging paper. Additionally, this approach presents an environmentally responsible alternative to petroleum-based coatings, adding value to lignin as a byproduct of the pulp and paper industry and supporting the transition toward more circular and sustainable packaging materials. Full article

Screening is a critical link in the separation of gold ores. However, issues such as the agglomeration of material masses and screen aperture blinding often lead to low screening precision and poor desliming performance, severely impacting the efficiency of subsequent crushing processes. To address these challenges, this paper proposes a rigid–flexible coupled screening method for viscous and moist gold ores. The time-frequency response characteristics of the screen surface motion were investigated, the influence of processing capacity and moisture content on screening performance was analyzed, and an industrial performance evaluation of the rigid–flexible coupled screen surface was conducted. Laboratory and industrial test results demonstrate that the rigid–flexible coupled screen surface exhibits a periodic, non-regular waveform with a maximum peak vibration intensity of 14.79 g. Screening efficiency is synergistically inhibited by moisture content and processing capacity. When the ore moisture content is below 3% and the processing capacity ranges from 15 to 22.5 t/(h·m²), the screening efficiency can exceed 85%. Compared with conventional screen surfaces, the implementation of the rigid–flexible coupled screen surface achieved a desliming efficiency of 91%, a maximum processing capacity in the crushing stage of 380 tons per hour, a nearly 12% improvement in the screening efficiency of the closed-circuit checking process for crushed products, and an approximately 8% reduction in the circulating load ratio of the crushing circuit. These enhancements collectively ensure the stable operation of both the screening and crushing processes. Full article

Rapid urbanization and the widespread use of impervious materials have intensified the urban heat island (UHI) effect, raising surface temperatures and energy demands. Conventional concrete pavements contribute significantly due to their high thermal conductivity and low reflectivity. This study systematically investigates the development of thermally efficient concrete paver blocks using sustainable alternative fine aggregates to mitigate heat accumulation while retaining a minimum compressive strength of 35–45 MPa (recommended for medium traffic). Unlike prior isolated studies, this research offers a comprehensive comparative analysis of three sand replacements—Vermiculite powder (12.5–50%), Perlite powder (20–80%), and Crushed Glass (7.5–30%)—in M30-grade concrete. Fresh and hardened properties were evaluated through slump, density, and compressive strength tests at 7, 14, and 28 days, while infrared thermography quantified surface temperature variations under controlled heat exposure. Results showed significant thermal improvements, with optimal mixes Vermiculite 25% (VC-25), Perlite 40% (PR-40), and Crushed Glass 15% (CG-15) reducing surface temperatures by 25.1 °C, 22.2 °C, and 18.2 °C, respectively, while maintaining compressive strengths of 47.8 MPa, 38.8 MPa, and ~58 MPa. VC-25 proved superior, achieving the lowest surface temperature (26.3 °C) and 48.8% lower heat absorption than conventional concrete. The study establishes optimal replacement thresholds balancing insulation and strength, supporting SDGs 11, 12, and 13 through climate-responsive, resource-efficient construction materials. Full article

Optic nerve (ON) injury by trauma induces progressive retinal ganglion cell (RGC) death and axonal loss, which leads to irreversible visual impairment and even blindness. Recently, we discovered that cellular senescence is involved in RGC survival regulation post-ON injury, and senolytic (dasatinib and quercetin) treatments can promote RGC survival and electroretinography activity. Here, we aimed to further evaluate the effects of dasatinib and quercetin on RGC dendrites and axons in mice with an ON crush injury. Longitudinal in vivo imaging analysis demonstrated that the RGC dendritic shrinkage was significantly reduced in mice with both individual and combined treatment of dasatinib and quercetin as compared to the vehicle treatment group. Similarly, dasatinib and quercetin treatments significantly promoted axonal regeneration post-ON injury as compared to the vehicle-treated mice. RNA sequencing analysis showed that the differentially expressed genes were enriched in the response to glucocorticoid, calcium ion binding, and cerebral cortex development. Sybr green PCR and immunofluorescence analyses validated that the axonal extension-related gene, meteorin (Metrn), was significantly upregulated in the dasatinib-only and combined dasatinib and quercetin treatments. In summary, this study revealed that dasatinib and quercetin alleviated RGC dendritic shrinkage and promoted axonal regeneration in mice after ON injury, probably mediated through meteorin, suggesting the dendrite repair and axonal regeneration potentials of dasatinib and quercetin for traumatic optic neuropathy treatment. Full article

Paddy field leveling is the foundation of high-yield rice cultivation. In response to the current issues of low leveling accuracy and the lack of efficient multi-operation machinery, an Integrated Multi-operation Paddy Field Leveling Machine was designed in this study. This machine can complete soil crushing, stubble burying, mud stirring, and leveling in a single pass. Combined with an adaptive control system based on Global Navigation Satellite System—Real-Time Kinematic (GNSS-RTK) technology, it enables adaptive and precise paddy field leveling operations. To verify the operational performance of the equipment, field tests were conducted. The results showed that the machine achieved an average puddling depth of 14.21 cm, a surface levelness of 2.16 cm, an average stubble burial depth of 8.15 cm, and a vegetation coverage rate of 89.33%, demonstrating satisfactory leveling performance. Furthermore, to clarify the feasibility and superiority of applying this equipment in actual rice production, experiments were conducted to investigate the effects of different field leveling methods on early rice growth, yield, and its components. One-way analysis of variance was employed to examine the differences in agronomic indicators between the different field leveling treatments. The results indicated that using this equipment for paddy field leveling, compared to traditional methods and dry land preparation, can improve the seedling emergence rate, thereby laying a solid population foundation for the formation of effective panicles. It also promoted root growth and development and increased the total dry matter accumulation at maturity, thereby contributing to high yield formation. Over the two-year experimental period, the rice yield remained above 9.8 t·hm⁻². This research provides theoretical support and practical guidance for the further optimization and development of subsequent paddy field preparation equipment, thereby promoting the widespread application of this technology in rice production. Full article

Reinforced concrete (RC) structural walls are essential for ensuring adequate lateral stiffness and strength in buildings located in seismic regions. However, many older structures incorporate nonconforming walls constructed with low-strength concrete, plain longitudinal reinforcement, and insufficient boundary confinement, and experimental data on such systems remain limited. This study investigates the seismic performance of two full-scale, relatively slender nonconforming RC wall specimens representative of older construction: one with no boundary confinement (SW-NC-FF) and one with insufficient confinement (SW-IC-FF). Both specimens exhibited flexure-controlled behavior, with initial yielding of boundary longitudinal bars occurring at an approximately 0.30% drift ratio and maximum reinforcement tensile strains of 0.006 (SW-IC-FF) and 0.015 (SW-NC-FF). Rocking governed the lateral response due to progressive debonding of the plain bars along the wall height, producing pronounced pinching and self-centering behavior. Failure occurred through longitudinal bar buckling and concrete crushing, with ultimate drift ratios of 2.0% and 1.5% and displacement ductility values of 4.0 and 4.3 for SW-IC-FF and SW-NC-FF, respectively. Experimental results were compared with backbone predictions from ASCE 41:2023, NZ C5:2025, and EN 1998-3:2025. While all three guidelines captured initial stiffness and yield rotations, their rotation-capacity predictions diverged, underscoring the need for improved assessment approaches for rocking-dominated, plain-reinforced walls. Full article

Following the Itaewon Halloween Crowd Crush of 29 October 2022, this study examines how public sentiment evolved on Naver, South Korea’s most influential digital platform. While prior research has focused on mainstream media and global social networks, little is known about localized discourse on Naver. To address this gap, we analyzed 2107 user-generated posts collected via Python-based web scraping across three time periods: the immediate aftermath, first anniversary, and passage of the Itaewon Special Law. Semantic network analysis, sentiment classification, and logistic regression were applied to uncover patterns in discourse and emotional tone. Results reveal a shift from grief and outrage in 2022 to demands for political accountability, safety reform, and memorialization by 2024. High-frequency keywords reflected media and government narratives, while low-frequency terms exposed grassroots voices and emotional nuance. Regression analysis confirmed statistically significant associations between sentiment, title length, and year. These findings suggest that digital platforms not only mirror public sentiment but also shape the emotional and political framing of national tragedies. By tracing sentiment over time, this study contributes to understanding how echo chambers, narrative framing, and temporal context interact in shaping collective responses to crisis. Full article

This study investigates the quasi-static axial crushing behaviour of carbon fibre-reinforced polymer (CFRP) tubes with variations incorporating polyurethane foam (PU) and aluminium tubes. Six different composite configurations were fabricated, including a baseline hollow CFRP tube and hybrid structures with foam and aluminium reinforcements. The mechanical response was evaluated through load–displacement behaviour and energy absorption. Visual inspection of the failure modes revealed distinct fracture mechanisms influenced by the type of reinforcement. The results indicate that incorporating aluminium significantly enhances load-bearing capacity, energy absorption, and crushing efficiency, with the sample containing four aluminium secondary tubes exhibiting the highest specific energy absorption. Meanwhile, foam-filled samples improved load-bearing capacity while mitigating brittle failure. These findings suggest that CFRP hybrid structures with aluminium and foam reinforcements offer promising solutions for lightweight Crashworthiness applications in the automotive and aerospace industries. Full article

Bio-inspired thin-walled energy-absorbing structures have attracted wide attention due to their excellent energy absorption characteristics. Inspired by the internal microstructure of the dactyl club of the marine stomatopod, Odontodactylus scyllarus, a bio-inspired corrugated sandwich tube (BCST) with a similar cross-sectional configuration, was designed. To verify the axial crashworthiness of the BCST, axial impact tests were first conducted on single-cell and four-cell thin-walled tubes to validate the models. Subsequently, the crashworthiness of the BCST is systematically investigated using ABAQUS/Explicit 6.14. The influences of material properties, the number of bio-inspired cells, wall thickness. Finally, a multi-objective optimization was conducted by combining the response surface method (RSM) with the non-dominated sorting genetic algorithm (NSGA-II), aiming to maximize specific energy absorption (SEA) and minimize crushing displacement (S), yielding the optimal design parameters for the BCST structure. Full article

To address the inefficient use of pruned grape branches and the high cost of orchard management, an integrated machine for collecting and crushing grape branches was developed, tailored to the distinctive viticulture methods in Xinjiang, China, and the physical properties of the branches. Based on a unified design scheme, the structural parameters of the collection mechanism and the suitable operating width were optimized through systematic theoretical analysis. The crushing unit was designed with attention to blade shape, quantity, and spatial distribution, while critical operational parameters—including blade dimensions, speed range, and key factors influencing crushing quality—were identified using kinetic analysis. A three-factor, three-level response surface experiment was designed via Design Expert software, incorporating crushing roller speed, pickup roller speed, and ground clearance of the pickup device as test variables. Pickup rate and acceptable fragment ratio were employed as evaluation indicators. Field tests showed that at a crushing roller speed of 2185 r/min, pickup roller speed of 105 r/min, and ground clearance of 10 mm, the pickup rate was 95.93% and the qualified fragmentation rate reached 97.19%, the machine met the operational requirements of achieving over 95% efficiency for both collection and crushing. This study provides a theoretical foundation and technical support for the mechanized treatment of pruned grape branches in Xinjiang. Full article

This paper presents the findings of an experimental study on the structural response of glass fiber-reinforced polymer (GFRP)-concrete composite beams. The connectors were fabricated from GFRP dowels, epoxy resin-saturated E-glass roving, and/or adhesive layers. The composite beams were subjected to a four-point bending test configuration and examined for their failure modes and load-deformation characteristics. The test results showed that the developed configurations of composite beams significantly outperformed the response of the standalone GFRP I-section profile and non-composite beams. The provision of a discrete interfacial connection successfully prevented the local and lateral torsional buckling of the profile, doubled the initial stiffness, increased the load-carrying capacity by around three times, and imparted a certain degree of ductility and reserve capacity to the otherwise brittle system. The failure occurred primarily due to the shearing of the web. Other modes of failure were observed in the form of the cracking/crushing of concrete, delamination of the laminate, and buckling/crushing of the web. The epoxy-bonded composite beams displayed the highest stiffness, while those with 45° inclined dowels exhibited the highest load-carrying capacity. The results were compared against those predicted by the available analytical expressions, and required modifications are suggested. Full article