Search Results (1,253)

Slope instability can cause severe disasters, making stability prediction essential. Machine learning has become a key tool for this purpose, as it avoids complex mechanical calculations and efficiently handles high-dimensional data. Currently, the data used in machine learning primarily originate from real-world cases. However, such cases are inherently limited in quantity and often fail to comprehensively represent all potential slope conditions. To address these limitations, this study proposes a method for constructing numerical simulation databases. Based on this, we develop a model establishment method for rapid evaluation of slope stability integrating numerical simulation with engineering cases. This study uses six characteristic parameters to assess slope stability, including unit weight γ, cohesion c, internal friction angle φ, slope angle α, slope height H, and pore pressure ratio r_u. Through extensive literature mining, we established a database of 684 engineering cases. Based on statistical analysis of input parameters, a numerical simulation scheme was designed. Batch calculations were performed using MATLAB to determine simulation results. The engineering case database was then partitioned into training and testing sets for model development and validation. Subsequently, the numerical simulation database was incorporated into the training set for retesting. Results demonstrate that when considering all predictive indicators, the prediction accuracy of the GRNN-based model improved from 85% to 88.3%, while the PNN-based model showed an increase from 69% to 88.3%. This study offers new insights for optimizing numerical simulation design and enhancing machine learning performance in slope stability prediction. Full article

The hollow fiber membrane humidification modules are used for indoor humidification in hot–dry regions and heating in winter. The module is composed of several flexible hollow fiber membranes, which are bent and displaced by gravity and fluid forces. This paper is a further study of previous work that reveals the internal relationship between the forces generated by vortex shedding and fiber vibration. The central trajectories of fibers in the flow field are described for various pulsating flow and fiber structure parameters. The effects of fiber displacement on fluid flow, heat transfer, and mass transfer performance at different parameters are discussed. The results show that the fiber displacement in the flow field consists of two components: (i) deformation caused by fluid drag force and gravity and (ii) periodic vibration caused by periodic lift and drag force as vortices shed at the fiber surface. The fiber vibration facilitates the vortex shedding on the fiber surface, which enhances the convective heat and mass transfer performance on the fiber surface. The average friction factor (f_m,v), Nusselt number (Nu_m,v), and Sherwood number (Sh_m,v) increased by 12.9%, 39.3%, and 20.0%, respectively, when the fiber vibrated compared to non-vibration. This implies that inducing fiber vibration can optimize the heat and moisture transfer performance. Full article

Indonesia’s financial system is bank-centric, with banks managing approximately 78% of the nation’s financial assets; therefore, the effectiveness of monetary policy transmission depends on banks’ responsiveness to the central bank’s interest rate policy (the BI Rate). However, a policy-relevant anomaly persists: deposit rate pricing is more strongly anchored to the Deposit Insurance benchmark (IDIC Rate) than to the BI Rate. This study argues that this research is significant because it identifies a “Dual Benchmark System” that traditional single-anchor models fail to address, representing a critical friction in emerging market transmission. This study examines this dual-benchmark paradigm and the associated asymmetric risks using a panel VAR with a Generalized Impulse Response Function (GIRF) on quarterly data for 63 commercial banks from 2010 to 2024. The results indicate that IDIC Rate shocks have a larger and more persistent effect on deposit rates than BI Rate shocks, generating asymmetric transmission risks. This dominance creates a structural “price ceiling” that keeps funding costs high, ultimately raising lending rates for borrowers and distorting deposit growth rates. Furthermore, this analysis reveals that external policy signals are far more influential than internal financial performance. This suggests that under the Basel III framework and prevailing financial regulations, banks prioritize liquidity compliance and safety net protection over internal operational efficiency. Macroeconomic shocks remain weaker than policy shocks and dissipate more quickly. This finding reveals a potential systemic coordination risk, implying an urgent need for tighter policy coordination between the Central Bank and the IDIC to reduce structural frictions, maintain transmission effectiveness, and protect long-term financial stability. Full article

Enhancing the thermal performance of the Trombe Wall is crucial for improving the energy efficiency of passive solar heating systems. This study presents a three-dimensional numerical analysis to investigate the combined effects of internal rib density and geometrical configuration on the thermo-hydrodynamic behavior of a Trombe wall. Using a finite-volume method with laminar flow assumptions based on the Reynolds number, the research is conducted in two sections. First, four rib densities (Nr = 3, 5, 7, and 9) are evaluated using a rectangular rib geometry to identify the best rib number. Subsequently, four innovative designs are compared: rectangular (Model A), semi-circular (Model B), crossed semi-circular (Model C), and spaced semi-circular (Model D) ribs. The findings indicate that while increasing rib count enhances heat transfer through secondary-flow intensification, improvements become marginal beyond Nr = 5 due to excessive flow resistance. At Re = 1600, the Nr = 5 configuration achieves a 68% increase in the average Nusselt number over a smooth channel while maintaining acceptable friction levels. The thermal enhancement factor of case Nr = 5 is the highest in all evaluated Re numbers. Regarding geometry, the model with crossed semi-circular ribs (Model C) provides the maximum thermal enhancement at Re = 1600, with nearly a twofold increase in heat transfer (compared to the smooth channel), albeit at the cost of higher pressure losses. Conversely, the spaced semi-circular ribs case (Model D) achieves the best thermal enhancement factor of 1.51, a 12.7% increase in heat flux, and a lower Poiseuille number. Overall, this study demonstrates that enhanced ribbed configurations can significantly improve Trombe Wall efficiency, with the spaced semi-circular design and five ribs. Full article

Reducing friction in the piston ring–cylinder liner contact is a key area for improving the efficiency of internal combustion engines. While tribological studies commonly focus on the top dead centre region using linear tribometers, the mid-stroke regime—with its higher sliding velocities—remains experimentally inaccessible to most conventional test methods. This study presents a rotating ring-on-liner tribometer that enables investigations at constant relative speed by transitioning the motion from oscillating to rotating. A cylindrical substitution geometry for the piston ring specimen is derived through a coupled elastohydrodynamic and asperity contact simulation approach to reproduce realistic load-sharing behaviour. Experimental results from starved lubrication tests demonstrate stable contact conditions with a low coefficient of variation in wear, confirming good reproducibility. Stepwise performed Stribeck tests at 40 °C and 100 °C reveal characteristic friction–velocity behaviour, including the transition from mixed to hydrodynamic lubrication. Although the test rig’s maximum sliding speed and steady-state thermal conditions differ from fired engine environments, the methodology closes an important gap between low-speed linear tribometers and complex floating-liner systems. The presented approach provides a flexible and robust platform for controlled parametric studies of ring-on-liner contacts under application-relevant lubrication regimes. Full article

In geotechnical engineering, operations such as foundation pit excavation, slope cutting, and tunnel boring often involve lateral unloading under plane strain conditions. This unloading pattern exhibits significant differences from the traditional axisymmetric triaxial loading path. To investigate the mechanical behavior of silt under such conditions, a series of plane strain tests were conducted using a self-designed plane strain apparatus, focusing on both vertical loading (constant lateral stress) and lateral unloading (constant vertical stress) paths. The results indicate that the failure of soil during unloading can be identified as the stage where the vertical deformation rate first increases and then decreases, corresponding to a distinct inflection in the stress–strain curve. The internal friction angle remained essentially constant regardless of the stress path, dry density, or consolidation stress ratio, while cohesion was higher under loading than under unloading. Failure deviatoric stress increased linearly with vertical consolidation stress and was unaffected by the consolidation stress ratio. The classical limit equilibrium condition remains valid for unloading under both isotropic and anisotropic consolidation. These findings provide a practical criterion for failure detection and highlight the necessity of adopting plane strain parameters in the design of lateral unloading engineering works. Full article

Model tests are effective for studying the entire deformation and evolution process of reservoir landslides. The sensitivity of similar materials to seepage effects is crucial to the accuracy of landslide model testing. Based on a fuzzy evaluation of in situ sliding zone soil, this study compared three similar materials, using shear tests and microscopic SEM to assess the similarity. The optimal similar material (sliding zone soil: bentonite: standard sand = 50%: 20%: 30%) with a water content of 13.5% and a permeability coefficient of 3.8 × 10⁻⁶ cm/s was identified, simultaneously matching physical–mechanical properties and seepage effects. When the proportion of in situ sliding zone soil exceeds that of bentonite, the in situ sliding zone soil dominates the strength. Cohesion depends on interparticle cementation force and water film viscosity. Bentonite modifies these forces in stages, leading to a trend where cohesion (c′) first increases and then decreases with rising water content, while the internal friction angle (φ’) decreases continuously. Model test results indicate the failure mode of reservoir landslides is a three-stage traction-braking failure, evolving from initial shallow deformation to deep progressive failure and finally to overall large-scale instability. The proposed similar material exhibits reliable physical–mechanical and seepage similarity and can be directly applied in physical model tests of reservoir-induced landslides to reproduce the hydro-mechanical coupling behavior of sliding zones. Full article

Replacing conventional chemical binders with natural polymers in geotechnically treated soil allows for the creation of more sustainable materials with both valuable ecological and mechanical properties. Xanthan gum and sodium alginate are natural polymers with excellent binding properties and water retention, which can help reduce carbon emissions. However, there is a lack of research on how to achieve optimal performance through the rational formulation of different biopolymers. This study investigates the use of these two natural biopolymers as binders (xanthan gum and sodium alginate) in slope-protection habitats treated with soil optimised using response surface methodology (RSM) within Design-Expert analysis software. The effects of xanthan gum concentration, sodium alginate concentration, and time, as well as their interactions on the properties of treated soil, ryegrass growth, and soil greenhouse gas emissions were evaluated, resulting in an optimized substrate formulation that balances good geotechnical properties with low environmental impact. Pot cultivation trials indicated that cohesion (c) and internal friction angle (φ) increased linearly with rising xanthan gum and sodium alginate concentrations, while the number of ryegrass plants (N_p) and root area ratio (RAR) decreased linearly with increasing binder concentration. Both CO₂ and CH₄ fluxes increased with rising binder concentrations. An analysis of variance (ANOVA) revealed that xanthan gum concentration had a stronger promoting effect on c and φ and a stronger inhibiting effect on N_p and RAR than sodium alginate. In contrast, sodium alginate concentration exhibited a stronger inhibitory effect on CO₂ and CH₄ fluxes. Through comprehensive optimization of geotechnical properties, vegetation growth, and greenhouse gas emissions, the optimal formulation was determined to be 0.885% for xanthan gum and 0.791% for alginate. The optimized composition resulted in increases of 38.6% and 19.1% for c and φ, respectively, while N_p and RAR increased by 7.7% and 15.0%, respectively. CO₂ and CH₄ fluxes decreased by 61.6% and 65.2%, respectively. This study contributes to advancing the sustainability of geotechnical treatments to favour vegetation regrowth. However, these materials will need to be further tested under field conditions to verify their effectiveness and duration. Full article

The tension control of carbon fiber diagonal weaving looms is severely affected by the coupling between structured friction and unstructured disturbances, leading to strong nonlinearities and time-varying uncertainties. To overcome the chattering and model-dependency issues inherent in traditional sliding mode control, a nonlinear dynamic model incorporating the Stribeck friction term was established. An Improved Adaptive Radial Basis Function-based Nonsingular Fast Terminal Sliding Mode Control (I-ARBF-NFTSMC) framework was then proposed. The framework adopts a divide-and-conquer composite compensation mechanism, in which a smooth Hyperbolic Tanh Fixed-Time Disturbance Observer (Tanh-FTDO) estimates external disturbances and suppresses chattering, and an Improved Adaptive Radial Basis Function (I-ARBF) neural network approximates and compensates internal nonlinear friction. Simulation results show that, compared with the conventional Fixed-Time Extended State Observer-based method (FESO-NFTSMC), the proposed controller achieves higher disturbance-estimation accuracy and tracking performance under sinusoidal, triangular, and composite disturbances. In composite-disturbance conditions, the steady-state mean-squared error is reduced by about 60%, the maximum tracking error decreases from 0.08787 N to 0.01965 N, and the settling time shortens by approximately 25.2%, while effectively mitigating high-frequency chattering. The proposed strategy achieves fast finite-time convergence with enhanced smoothness and robustness, providing a real-time executable solution for high-precision tension control in complex nonlinear weaving processes. Full article

In geotechnical foundation engineering, the bearing capacity and settlement behaviour of clay soils are key parameters governing foundation performance. Insufficient bearing capacity and excessive settlements limit economical foundation design and may lead to increased structural deformations. This study investigates the physical and mechanical properties of low-plasticity (CL) and high-plasticity (CH) clay soils obtained from boreholes drilled in Düzce Province, Türkiye, where bearing capacity, settlement, and relevant soil parameters were determined through field and laboratory testing and subsequently evaluated using statistical analyses. The calculated bearing capacity values ranged from 192 to 556 kPa, while settlement values varied between 0.88 cm and 5.83 cm. The corresponding maximum-to-minimum ratios were approximately 2.89 for bearing capacity and 6.62 for settlement. The effects of unit weight, water content, particle size distribution, groundwater level, internal friction angle, and cohesion on the bearing capacity and settlement behaviour of the examined clay soils were systematically assessed. The results indicate that unit weight is the most influential parameter for increasing bearing capacity and reducing settlement in CL-type soils, whereas the cohesion coefficient is the dominant parameter in CH-type soils. The results indicate that variations in shear strength and moisture-related parameters exert a significant influence on foundation performance. The findings provide quantitative insight into the relative impact of key soil parameters and offer practical implications for the design of building foundations in clayey soils under similar geological and geotechnical conditions. From a practical perspective, the findings support foundation design, especially in earthquake-prone areas, by accounting for soil bearing capacity and ensuring that settlements remain within permissible limits to maintain long-term structural performance. Full article

Root functional traits are critical predictors for vegetation-mediated slope stabilization in reservoir drawdown zones. This study quantified the biomechanical linkage between single-root tensile traits and macro-scale soil shear strength for three dominant herbaceous species (Cynodon dactylon, Digitaria sanguinalis, and Imperata cylindrica) in the Three Gorges Reservoir. Single-root tests ($n=15$) revealed a robust diameter-dependent trade-off between tensile load capacity ($F_{max}$) and material efficiency (${\sigma }_t$). Direct shear tests on undisturbed root–soil composites demonstrated that root reinforcement significantly enhanced soil stability, primarily by increasing apparent cohesion (c) rather than internal friction. Cynodon dactylon exhibited the highest reinforcement efficacy, increasing cohesion by >50 kPa compared to root-free soil, supported by its superior tensile strength. These findings establish a trait-based mechanistic framework for species selection, suggesting that prioritizing species with high intrinsic tensile efficiency can effectively mitigate shallow erosion under fluctuating hydrological conditions. Full article

The shear strength of rock discontinuities is critical for the stability of deep underground projects. However, its accurate determination is hindered by the discreteness of natural joints and the limitations of conventional direct shear tests, which operate under simplified two-dimensional stress conditions, unlike the true triaxial (σ₁ > σ₂ > σ₃) in situ state. This study introduces and validates a multistage true triaxial direct shear testing method as a practical solution. Through controlled pre-peak unloading, complete failure envelopes were successfully obtained from single specimens of jointed granite and intact marble with minimal strength degradation. The results demonstrate that lateral stress significantly enhances the peak shear strength, characterized by a marked increase in cohesion coupled with a slight decrease in the internal friction angle. For intact marble, increasing the lateral stress from 0 to 20 MPa raised the cohesion by approximately 67% (from 34.9 to 58.4 MPa), while the friction angle decreased from 49.3° to 42.8°. For jointed granite, cohesion showed a more variable but consistently strengthening trend with confinement, accompanied by a minor adjustment in the friction angle. Acoustic emission monitoring confirms that pre-peak unloading confines damage accumulation to microcrack reactivation. From a fracture mechanics perspective, the strength enhancement is attributed to the suppression of tensile crack propagation and the promotion of shear localization under three-dimensional confinement. Collectively, this work establishes a novel experimental framework and elucidates the mechanism by which lateral stress governs the shear behavior of hard rock, offering direct implications for the design and stability assessment of deep excavations and related geo-engineering projects. Full article

The rapid evolution of live-streaming commerce has reshaped retail supply chains, shifting market dominance from manufacturers to influential streamers. Despite this shift, the internal mechanisms of selling efforts and paid traffic acquisition remain underexplored. To bridge this theoretical gap, we develop a game-theoretic framework to model the endogenous power structure and compare the streamer-led top-tier (KS) mode and the brand-led ordinary (MS) mode. Our analytical results reveal three key theoretical insights. First, we establish strict positive monotonicity between streamer influence and equilibrium decisions. Regardless of the power structure, an increase in influence consistently drives the streamer to intensify operational inputs while simultaneously inducing the brand to raise the direct selling price. Second, consumer sensitivity acts as a positive driver of the top-tier mode. Higher sensitivity motivates the streamer to scale up sales efforts and paid-traffic volume, which corresponds to an optimal increase in the brand’s retail price. Moreover, the top-tier mode exhibits negative sensitivity to operational costs. We prove that rising costs lead to a significant reduction in the streamer’s operational portfolio and, consequently, to a decrease in the brand’s price, indicating that the high-input equilibrium is constrained by cost frictions. From a managerial perspective, numerical experiments reveal not a “Consensus on Scale” but a “Conflict on Structure.” Specifically, brands maximize profit by collaborating with top-tier streamers, while streamers maximize profit by attaining top-tier influence. However, the brand receives more profit by relinquishing channel leadership with respect to the decision hierarchy. In contrast, the streamer is less profitable as a leader than as a follower due to the “leadership trap,” in which greater operational burdens outweigh first-mover advantages. Full article

Corrugated pipes are widely used due to their mechanical flexibility; however, their corrugated internal geometry is associated with increased hydraulic losses. Previous studies have reported a non-classical increase in friction factors with pipe diameter at identical Reynolds numbers, although the underlying mechanisms and related energy implications have not been fully clarified. In this study, turbulent flow behavior and pumping power requirements in stainless-steel corrugated pipes are investigated using a validated three-dimensional Computational Fluid Dynamics (CFD) framework based on the SST k–ω turbulence model. The numerical predictions show good agreement with available experimental data, with maximum deviations remaining below approximately 12% across the validated range. The results indicate that both friction factor and pumping power increase systematically with pipe diameter under dynamically similar flow conditions, demonstrating that Reynolds-number similarity alone does not ensure flow similarity in corrugated geometries. From an energy perspective, an Energy Penalty Factor (EPF) is introduced to quantify corrugation-induced pumping requirements, and a surrogate correlation is developed to relate EPF to Reynolds number and selected dimensionless geometric parameters. The proposed formulation exhibits strong predictive performance within the investigated parameter space (R² = 0.972) and enables rapid, CFD-free estimation of energy penalties for preliminary design and comparative evaluation of corrugated piping systems. Full article

Twin shield tunneling in river-crossing soft soils faces increased risks like face instability, largely due to unclear mechanisms linking water level fluctuations to ground settlement. To address this issue, a 3D fluid–solid-coupled FLAC3D model is developed based on the Zhanqiaogang section of Hangzhou Metro Line 15. Specifically, the model simulates four hydrological conditions: low water, normal water level, high water level, and flood level. It examines their effects on ground settlement, stress distribution, and pore water pressure during twin-tunnel excavation. The results indicate that the maximum ground surface settlement on the left alignment under flood-level conditions increased by 41.58% compared with that under normal water levels. On the right alignment, surface settlement increased from 6.54 mm under normal water levels to 8.54 mm under flood conditions, representing a 30.6% increase. A sensitivity analysis is also conducted on pore water pressure, soil internal friction angle, and support stiffness. Results show that ground settlement increases with rising river levels, mainly due to elevated pore pressure reducing soil strength. Sensitivity analysis confirms pore pressure as the key factor influencing deformation. Numerical results align well with field data, highlighting the critical role of hydraulic boundaries. Based on these results, control measures are proposed to provide practical guidance for mitigating settlement in similar river-crossing tunnel projects. Full article