Search Results (2,158)

In a seepage control system composed of geomembranes, the mechanical properties of the geomembrane welds directly determine the overall safety and durability of the system. To clarify the influence of welding parameters on the mechanical properties of the welds, this paper prepares weld specimens using different welding processes and systematically investigates the effects of welding temperature, welding pressure, and welding speed on the mechanical properties of double wedge welds in HDPE geomembranes through peel tests, shear tests, and DIC deformation measurement technology. The results indicate that the peel strength of HDPE welds has no linear correlation with welding pressure but there exists a threshold effect. The peel strength exhibits an exponential relationship with welding temperature and a Gaussian relationship with welding speed. The shear strength of the welds can be fitted by an exponential function for all three welding parameters. The coefficient of determination (R²) for each of the above fitting equations is higher than 0.9. Under different welding parameters, the yield strength of the double welds is slightly lower than that of the base material (approximately 89–94% of the base material), while the yield strain decreases more significantly (to 62–81% of the base material). Observations of the weld deformation distribution using DIC show that when the specimen elongation is below 11%, strain is concentrated near the weld; after reaching the yield strain, necking occurs; and the strain concentration shifts to the necking region. As the elongation further increases, significant plastic yield deformation occurs in the necking region, with a maximum strain of 500%. Full article

Molecular dynamics simulations were performed to investigate the nanometric cutting of polycrystalline oxygen-free copper using a single-crystal diamond tool. The effects of grain size, tool geometry (rake angle and edge radius), cutting speed, and ambient temperature on atomic migration, dislocation activity, and tool wear were systematically analyzed. The results indicate that material removal is dominated by cutting-induced amorphization and the formation of hcp-coordinated defect structures, while dislocation activity governs plastic deformation and cutting force fluctuations. A damaged subsurface layer, composed of amorphous structures, hcp-coordinated defects, and residual dislocations, is formed beneath the machined surface. Increasing grain size reduces grain-boundary-induced stress concentration and suppresses subsurface damage. A larger rake angle facilitates chip removal and reduces damage, whereas a larger edge radius intensifies dislocation activity and amorphization. Higher cutting speeds reduce lattice distortion and subsurface damage but increase stress concentration on the tool. Elevated temperature enhances atomic mobility, promoting amorphization and subsurface deformation while accelerating tool wear. These findings provide insight into the nanometric cutting behavior of polycrystalline copper and offer guidance for optimizing process parameters to improve surface integrity and tool life. Full article

We developed a multi-channel and multilayered polydimethylsiloxane (PDMS) microfluidic platform that integrates cyclic mechanical stimulation, independent reagent delivery, and real-time optical observation within a single device. The platform employs a four-layer architecture comprising a pneumatic valve control layer, an observation channel for cell culture and imaging (24 mm × 4 mm), a medium perfusion layer with independent inlet ports, and a vacuum actuation layer that deforms a 200 $\mathsf{\mu }$m PDMS membrane under −20 kPa cyclic pressure at 1 Hz. Cyclic membrane strain of 10% was calibrated using fluorescent bead tracking and image analysis. Finite element analysis based on nonlinear Föppl–von Kármán plate theory confirmed that the central cell culture region (60% of membrane area) exhibits a mean von Mises strain of 14.2% with a uniformity of 81.3% (CV = 18.7%), validating relatively uniform mechanical stimulation across the culture surface. As a proof-of-concept, human aortic smooth muscle cells (CRL-1999) cultured under cyclic strain showed significant upregulation of HIF-1$\alpha$ expression (2.5-fold, $p<0.01$) and pronounced F-actin stress fiber alignment visualized by fluorescence microscopy, confirming the platform’s capability for mechanotransduction studies and real-time cellular observation. The multi-channel architecture enables multi-condition parallel testing by simultaneously introducing different reagent concentrations through independent inlet ports while maintaining identical mechanical parameters across all channels, providing a versatile tool for systematic investigation of cellular responses under controlled biomechanical conditions. Full article

Colletotrichum species are among the most destructive phytopathogens worldwide, with appressorium-mediated penetration representing a critical stage in host infection. Targeting this morphogenetic transition offers a promising strategy for sustainable disease control by interfering with the infection process rather than solely inhibiting fungal growth. In this study, chitosan–κ-carrageenan nanoparticles (CS–κ-CRG) without and with lysozyme (CS–κ-CRG/Lz) were synthesized, characterized, and evaluated for their ability to inhibit appressorium formation in Colletotrichum siamense, a strain exhibiting low sensitivity to chitosan. The nanoparticles showed monodisperse size distributions, with hydrodynamic diameters of 503 and 333 nm for CS–κ-CRG and CS–κ-CRG/Lz, respectively, positive surface charges of approximately +26 mV, spherical morphology, and a lysozyme encapsulation efficiency of 63%. Both formulations significantly reduced conidial viability and delayed germination, inducing morphological alterations such as conidial swelling, hyphal deformation, and vacuolization. Fluorescence microscopy using calcofluor white and propidium iodide revealed disturbances in cell wall organization and loss of membrane integrity. Both nanomaterials markedly affected appressorium development in a concentration- and formulation-dependent manner. Notably, CS–κ-CRG/Lz showed stronger suppression of appressorium formation, whereas at 200 µg·mL⁻¹, CS–κ-CRG nanoparticles stimulated appressorium formation, suggesting that sublethal nanoparticle stress may trigger compensatory or hyper-pathogenic responses. These findings highlight the potential and complexity of utilizing chitosan-based nanomaterials for phytopathogen management and emphasize the importance of mechanistic and dose–response evaluations before field application. Full article

Although fault-controlled instability of underground excavation has been widely studied, systematic analyses of how key fault geometric and mechanical parameters affect surrounding-rock behavior in deep hard-rock mine roadways remain limited. This study takes a deep roadway as the engineering background and uses numerical simulation to investigate the effects of fault thickness, fault dip angle, fault mechanical properties, and contact parameters on the initial deformation state, post-excavation deformation, and plastic-zone evolution of surrounding rock. The results indicate that the surrounding rock is already in a non-uniform initial state controlled by fault disturbance prior to excavation. Increasing fault thickness expands the initial high-deformation zone; fault dip angle mainly changes the spatial distribution pattern of the initial deformation field; and increasing either the fault mechanical parameters or the contact parameters reduces deformation concentration in the vicinity of the fault. After roadway excavation, deformation is mainly concentrated in the fault–roadway intersection zone, and roof deformation along the roadway axis shows distinct local peaks and an asymmetric distribution. The maximum roof deformation continues to increase with the increase of fault thickness (the deformation increases by 218% from 1 m to 5 m), and smaller fault dip angle conditions are prone to local large deformation.. In contrast, higher fault mechanical parameters and contact parameters can both effectively suppress roof deformation, with the contact parameters exerting more significant control (as the contact parameter increased from C1 to C5, the maximum roof deformation decreased by approximately 75%). The plastic zone mainly develops at the fault–roadway intersection and is dominated by shear plasticity, accompanied by tensile plasticity. Increasing fault thickness significantly enlarges the plastic-zone volume and strengthens the shear-dominated failure characteristic; fault dip angle mainly controls the propagation direction and morphology of the plastic zone; and increasing the fault mechanical parameters and contact parameters both help reduce the extent of the plastic zone. These findings can provide a theoretical basis for zoned support design and differentiated stability control of roadways crossing faults in deep metal mines. Full article

This study tested quarter-scale adobe masonry walls under monotonic in-plane loading, considering the effect of water content at the foundation–wall interface, fiber type, and openings (i.e., door, window). Seven walls were constructed with unstabilized adobe bricks containing either cut straw or sisal fibers and mud mortar. Gravimetric water content (w_b) at the foundation–wall interface (i.e., wall base) varied by test wall, ranging from 2.4 to 4.9% by dry mass. The walls were instrumented to measure in-plane and out-of-plane displacements and vertical deflections during the load tests. Greater water contents at and near the wall base shifted cracking toward the lower courses and along the foundation–wall interface; however, the peak load capacity did not vary significantly with w_b but was strongly influenced by crack trajectory, including whether cracking diverted into the foundation or propagated rapidly along the foundation–wall interface. Peak loads ranged from 1928 N (433 lb) to 6517 N (1465 lb). Fiber type influenced deformation behavior of the walls, with sisal-brick walls generally developing larger vertical deflections and, in some instances, larger peak in-plane displacements than straw-brick walls. Window and door openings altered crack initiation and propagation by concentrating cracking at opening corners and producing segmented mechanisms, increasing in-plane displacements in some cases, but still sustaining comparatively large peak loads. Full article

The critical metal lithium (Li) is increasingly sourced from spodumene and petalite pegmatite deposits due to their relatively high grades, lower mining environmental impacts and widespread global distribution. However, there are numerous gaps in our understanding of their genesis and the formation of unzoned or poorly zoned Li pegmatites is particularly difficult to explain. To investigate this, both spodumene-bearing and non-mineralized pegmatites and aplites are studied in the Moylisha segment of the Leinster pegmatite belt of SE Ireland, which were emplaced within the East Carlow Deformation Zone (ECDZ). Trace element modeling suggests that granite melts can achieve Li concentrations high enough (~5000 ppm) to crystallize spodumene. However, once crystallization begins, Li levels will drop rapidly below this threshold. While Li could be replenished by incoming melts, there is no supporting textural evidence for this, such as internal magmatic contacts, crosscutting relationships, or mingling. We test the hypothesis that low viscosity, Li-rich fluids from underlying reservoirs, most likely almost fully crystallized granite magmas or mush, continuously migrate through the heterogeneously crystallizing pegmatite-forming melts by percolative reactive flow, refertilizing interstitial melt by diffusion under favorable geochemical gradients. The flow of fluids is likely maintained due to their low relative density and periodic shearing within the ECDZ. Fluids with >10,000 ppm Li, derived by >95% crystallization (Rayleigh fractionation) of a granite magma, are shown to be capable of refertilizing a pegmatitic crystal mush after its emplacement. Supporting evidence includes macro- and micro-textures indicative of paragenetically late spodumene crystallization along apparent fluid flow pathways in mineralized pegmatites and aplites. Similar features are common in spodumene pegmatites worldwide and suggest that Li upgrading by fluid flow through crystallizing spodumene pegmatites may be a key process in enhancing Li grades and in some cases in producing economically favored low-Fe spodumene. Full article

In this study, scanning electron microscopy (SEM) analysis is used to reveal the real microstructure of C75S steel and to compare grain morphology and deformation features with numerical predictions. A micro-scale finite element model of C75S steel is developed to investigate its tensile response in order to understand how steel actually deforms and fails at the microstructure level. Subsequently, the validated microstructural model is employed to simulate the cutting process using the finite element method, focusing on stress concentration and damage initiation at the grain and interface zones. The results demonstrate that microstructural modelling provides improved insight into deformation and fracture mechanisms compared to homogenised approaches, highlighting the critical role of cementite distribution and interfacial behaviour during tensile loading and micro-scale cutting. The cementite particle sizes in C75S steel range from approximately 0.5 to 2.0 µm, with circularity values between 0.7 and 0.95 and a volume fraction of about 10–12%. The proposed framework offers a robust basis for predicting the cutting performance of high-carbon steels. Full article

This paper examines whether a residual structural state extracted from cross-asset downside-risk dependence contains incremental information for forecasting next-day market downside risk beyond a strong heterogeneous autoregressive (HAR) benchmark. The empirical analysis uses Binance intraday data from September 2019 to December 2025 and a fixed sample of 24 liquid cryptocurrencies obtained through explicit data-quality screening and sample diagnostics. The forecasting target is the log of an equal-weight cross-sectional downside-risk index constructed from strictly valid asset-level realized downside semivariance measures. The empirical design is deliberately conservative: the market sample is fixed ex ante, the target is evaluated against Bitcoin (BTC) and Ethereum (ETH) dominance diagnostics, and asset-level HAR-type models are estimated recursively to generate ex-ante one-step-ahead residuals, from which rolling residual-dependence matrices and structural signatures are constructed. The selected residual state contains four components: average residual correlation, Frobenius-type deformation, influence concentration, and influential-set turnover. The evidence supports three qualified conclusions. First, the full residual state attains the lowest average QLIKE loss relative to the HAR benchmark, although the corresponding Diebold–Mariano test under the primary QLIKE loss does not reject equal predictive accuracy at conventional levels. Complementary Clark–West evidence on the nested log-scale comparison supports incremental predictive content for the level-state and full-state augmentations. Second, the strongest forecasting evidence comes from the full state rather than from deformation-only specifications. Third, event-window diagnostics show that structural reorganization is most pronounced around stress-entry and extreme-risk episodes, supporting an onset-sensitive rather than a long-lead early-warning interpretation. Overall, the evidence supports a cautious and statistically qualified predictive conclusion: residual market structure may contain incremental information for short-horizon downside-risk forecasting in cryptocurrency markets, especially around stress onset, but the result should not be interpreted as a decisive primary-loss improvement or as evidence that deformation alone dominates a strong benchmark. Full article

Truss-like and minimal surface-based cells are among the promising candidates for novel impact-resistant structural designs. However, the influence of cell configurations on impact resistance performance remains unclear. In this paper, the energy absorption characteristics of three truss-like cells (BCC, Fluorite, and Diamond) and three minimal surface cells (Gyroid, Primitive, Diamond) are systematically compared using quasi-static compression experiments and refined numerical models. Experimental results indicate that minimal surface cells possess clearly superior specific energy absorption performance. Specifically, the Gyroid (G-surface) exhibits a specific energy absorption (25 kJ/kg) approximately 2.3 times greater than the highest value among truss-like cells (11 kJ/kg), accompanied by an extended plateau strain by about 20%. Additionally, due to stress concentration at joints, truss-like cells show notably lower plateau forces compared to minimal surface cells. However, truss-like cells demonstrate better manufacturing precision and quality control, as evidenced by a relatively small average weight deviation (about 1.2%). Furthermore, numerical simulations were conducted to explore differences in deformation mechanisms between two representative cells. Results reveal that the BCC structure absorbs energy through localized shear band formation induced by point plastic hinges, whereas the Primitive (P-surface) minimal surface structure achieves more uniform plastic deformation via distributed line plastic hinges. Finally, impact simulations of protective structures show that the maximum stress in the P-surface-filled structure is reduced by 4.6% compared to the BCC-filled structure, and stress distribution uniformity is improved by 37%. The findings from this study provide valuable references and data support for future anti-impact structural designs. Full article

Concentrating solar power (CSP) is a promising renewable energy technology, and molten-salt storage tanks are core equipment for ensuring its stable operation, where the foundation plays a decisive role in the structural design and safe service of the tanks. To address the lack of systematic stress and deformation analysis for large high-temperature molten-salt storage tank foundations, this study aims to investigate the mechanical and thermal behaviors of the foundation under actual operating conditions. A numerical simulation method was adopted to perform stress and deformation analysis on the foundation of a large high-temperature molten-salt storage tank. The results show that the maximum von Mises stress of 229.26 MPa is concentrated on the steel plate of the foundation. The radial deformation of the foundation was calculated, and the maximum radial deformation reaches 36.64 mm, which provides an important reference for the design of both the foundation and the entire molten-salt storage tank. Under the given internal pressure and operating temperature, the height of the molten salt has a significant impact on the radial deformation of the foundation. Additionally, ambient temperature variations from −28.7 °C to 20 °C exert little influence on the temperature distribution of the foundation, indicating that the thermal insulation performance of the tank is excellent. The findings of this study can provide theoretical support for optimizing the design and operation strategies of molten-salt storage tanks, particularly their foundations. Full article

Relying on the Dujiangyan Irrigation Project, the Siguniang Mountain Rail Transit project, and the Balang Mountain No.1 Large Longitudinal Slope Tunnel Project, this paper systematically studies the mechanical response of the surrounding rock and support structure induced by TBM tunneling in composite stratum by using the methods of indoor test, similar model test and numerical simulation. In model tests with different rock dip angles (0°, 10°, 20°, 30°), the main findings are as follows: (1) The maximum settlement of the arch crown reaches −4.89 mm (monitoring surface 2, 20° dip angle), the displacement of the arch waist is smaller than that of the arch crown, and the deformation of the soft rock section is more significant. (2) The peak radial surrounding rock pressure generally occurs at a distance of 5 cm from the tunnel wall, with the highest pressure in the soft rock area of the arch waist reaching 16.807 kPa (monitoring surface 4). (3) The lining stress increases with the increase in rock dip angle, and the stress distribution on the same monitoring surface shows as arch waist > arch crown > arch shoulder, with the maximum stress concentrated in the soft rock area of the arch waist. Then, the finite difference method is used for numerical simulation to analyze the convergence deformation mechanism in the composite formation. The results indicate a strong consistency between the simulated displacement/stress patterns of the surrounding rock and lining structure and the experimental data. The research results provide a theoretical basis and experimental reference for the design and construction of similar projects. Full article

Airfoil fin Printed Circuit Heat Exchangers (PCHEs) offer significant advantages in reducing flow resistance, promoting turbulence, and enhancing heat transfer performance due to their discrete fin configuration. However, compared with conventional continuous-channel structures, the geometric discontinuities and sharp trailing edges introduced by discrete fins tend to induce severe stress concentration at the fin roots, resulting in a more complex structural response. In this study, a PCHE core with NACA0020 airfoil fins is investigated. Finite element analysis combined with a sequential one-way thermo-structural coupling approach is conducted to characterize the fins’ stress and deformation behavior under high temperature and pressure. The plate region is evaluated based on the linear elastic stress criteria specified in ASME Boiler and Pressure Vessel Code Section III, while localized yielding regions such as the fin roots are assessed using an equivalent plastic strain indicator. Results indicate that the structural response of the PCHE core is dominated by pressure loading under the investigated operating conditions with ΔT = 18 °C and ΔP = 12.05 MPa, whereas thermal stress caused by constrained thermal expansion mainly modifies local stress distributions and has a limited effect on global deformation. Owing to the discontinuous support provided by discrete airfoil fins, the fin roots act as the primary load-transfer path and sustain higher stress levels. The maximum von Mises stress is observed at the trailing edge of the fin root on the high-pressure side, while the largest deformation occurs in the unsupported plate region and is governed by bending. Parametric analysis indicates that, within the investigated parameter range, a fully staggered fin arrangement promotes more uniform load distribution and exhibits the most favorable structural response. In contrast, increasing the fin chord length and relative thickness reduces the overall load-carrying capacity of the core. Finally, a power-law predictive correlation for the maximum total plate deformation was developed, showing that the parameter influence on plate structural response follows the order horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e) > staggered pitch (L_s). In contrast, normalized sensitivity analysis of the maximum fin-root von Mises stress shows the order staggered pitch (L_s) > horizontal pitch (L_h) > vertical pitch (L_v) > channel etching depth (L_e), indicating that global plate deformation and local fin-root response are governed by different structural mechanisms. Full article

To elucidate the role of environmentally friendly oxide additives in a molybdenum disulfide (MoS₂)-based solid lubricant, this study investigates the tribological behavior of a MoS₂–TiO₂ coating deposited via a spray-bonding process and compares it with a commercial Sb₂O₃-containing formulation (Everlube 620C). Interfacial characteristics and wear-related mechanisms were systematically analyzed using scanning electron microscopy (SEM), focused ion beam (FIB), Raman spectroscopy, and X-ray diffraction (XRD). The MoS₂–TiO₂ coating exhibited a higher steady-state coefficient of friction (0.35–0.45) and wear compared to the baseline. Its wear behavior was governed by fracture-induced three-body abrasion, driven by the hard and brittle nature of TiO₂, which promotes stress concentration at particle–matrix interfaces, crack initiation, particle pull-out, and debris generation. These processes suppress the formation of a desirable MoS₂-rich tribo/transfer film, leading to deformation-dominated friction. Overall, the findings indicate that the intrinsic mechanical properties and interfacial behavior of TiO₂ limit its effectiveness as an additive in MoS₂-based coatings, highlighting the importance of additive selection and compatibility in achieving optimal tribological performance. Notably, this study was performed at an additive volume fraction equivalent to that of Sb₂O₃ in Everlube 620C, serving as a foundation and indicating that further optimization of TiO₂ particle size and concentration is required to achieve comparable performance. Full article

Return-type cable suspension bridges transfer the main-cable force to the anchorage predominantly in the horizontal direction, which may induce coupled sliding–overturning instability of the anchorage–foundation system. This study examines the stability of return-type cable gravity anchorage using the composite anchorage of the Jixin Expressway Yellow River Three Gorges Bridge as the prototype. A 1:100 laboratory specimen was designed based on similarity theory and tested under incremental loading until failure. Four configurations were considered by combining two embedment ratios (1/4 and 1/2) with two base types (flat-base and shear-keyed). Horizontal displacement, overturning angle, interface contact stress, and foundation strain were monitored throughout loading. Because the return-type cable transmits a predominantly horizontal force, the anchorage–foundation contact stress exhibits pronounced asymmetry between the toe and heel regions, and this stress asymmetry governs the coupled sliding–overturning instability mode. The shallow flat-base case exhibited a distinct displacement and contact stress jump at high load levels, followed by rapid rotation, indicating slip–tilt coupled instability. Increasing embedment improved confinement and delayed the onset of nonlinear deformation, but the flat-base configuration still showed pronounced toe stress concentration. By contrast, the shear-keyed base mobilized cooperative bearing of the surrounding foundation, producing smoother stress–strain evolution and higher ultimate capacity. Moreover, the shear-keyed base mitigates the stress asymmetry at the anchorage–foundation interface, leading to a more symmetric distribution of contact pressure and improved overall stability. Three-dimensional finite-element simulations reproduced the measured trends in displacement, stress concentration near the toe, and strain development, providing independent verification. The results clarify the dominant instability mechanism of return-type cable gravity anchors and offer design implications for embedment depth and shear-keyed base detailing. Full article