Search Results (607)

Offshore wind farms are increasingly and rapidly expanding due to their ability to harness strong and consistent wind energy resources. Large offshore wind farms are connected to mainland grids through High-Voltage Direct Current (HVDC) technology. However, offshore wind farms can often experience disturbances related to sudden wind changes, voltage drops/dips, faults related to converter switching, and unbalanced grid conditions which affect both the HVDC operation and wind turbine output. As a result, there is a growing need for more advanced and reliable modeling and monitoring tools. Moreover, traditional proportional-integral (PI) controllers are widely applied in wind turbines and HVDC systems due to their simple structure, easy implementation, and reliability. However, PI controllers perform poorly under non-linear and abnormal/fast-changing conditions, especially during sudden drops in wind power and grid faults. With this background, this paper first develops a digital twin model of an offshore wind farm that enables remote operation and monitoring of individual wind turbines. Also, an artificial intelligence (AI)-based controller, namely a fuzzy logic controller (FLC), is proposed to maintain transient stability of a full digital twin-based offshore wind farm connected to the HVDC grid under fault conditions. The effectiveness of the proposed FLC is demonstrated by considering a digital twin-enabled 700 MW offshore wind farm. The performance of the proposed FLC has been compared with that of the PI controller. Simulations performed by the MATLAB/Simulink software show that during the moderate voltage dip at 15 s, the PI controller experienced a 29.8% power reduction with a recovery time of approximately 9 s, whereas the FLC reduced the power drop to 23.1% and recovered within 6 s. During the severe converter disturbance at 15 s, the PI controller recorded a 36.9% power reduction compared to 23.4% for the FLC. Similarly, during the short-duration turbulence at 15 s, the PI controller exhibited a 36.73% power drop and recovered in approximately 7 s, while the FLC limited the power reduction to 19.17% and recovered within 5s. Overall, the FLC provided improved voltage stability, faster recovery, reduced oscillations, and superior fault ride-through capability compared with the conventional PI controller, demonstrating its effectiveness for digital twin-enabled offshore wind farm application. Full article

Fractures are widely developed in deep coal-mine surrounding rocks. They weaken the load-bearing capacity and energy-storage capacity of rock specimens, which may induce surrounding-rock deformation, roof collapse, and other hazards. Current studies on fractured rock masses mainly focus on a single parameter, such as fracture number or fracture dip angle. However, their coupled effects remain unclear. Integrated analyses of mechanical behavior, crack propagation, and energy evolution are also limited. In this study, uniaxial compression simulations of intact sandstone, single-fracture sandstone, and double-fracture sandstone were conducted using PFC^2D. The effects of fracture number and fracture dip angle on mechanical properties and failure characteristics were investigated. The results show that fractures reduced the peak stress and modulus of elasticity. A stronger weakening effect was observed with increasing fracture number. With increasing fracture dip angle, both peak stress and modulus of elasticity showed a V-shaped trend. The minimum peak stress occurred at 15°, while the minimum modulus of elasticity occurred at 45°. Sandstone failure was mainly dominated by tensile cracks. At 15°, the total crack number was the lowest, with 932 and 818 cracks for single-fracture and double-fracture specimens, respectively. Energy analysis showed that increasing fracture number reduced elastic strain energy and promoted dissipated energy. The weakest energy-storage capacity was observed at 30°. Overall, fracture number and fracture dip angle jointly controlled strength degradation, crack propagation, and energy evolution. This study provides a reference for fracture–damage assessment and disaster prevention in deep coal-bearing sandstone. Full article

Background/Objectives: One of the ongoing clinical constraints is limiting microbial growth on prostheses, justifying the need for material surface enhancements to reduce microbial complications. This study aimed to investigate a potentially applicable and reproducible coating technique to overcome clinical microbial challenges. Methods: Silver (Ag) nanoparticles (NPs) were applied to three types of materials through spray, spin, and dip coating techniques. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray fluorescence (EDXRF), and inductively coupled plasma optical emission spectroscopy (ICP-OES) were performed. Subsequent optimization of spray numbers was determined. Antimicrobial performance of one- and three-layered coatings was evaluated through agar diffusion, direct contact, and adhesion (time-dependent) assays against Pseudomonas aeruginosa (P. aeruginosa). Results: Spray coating exhibited superior coating uniformity. In total, 15 sprays were determined as an effective number for a single-layer coating. EDS confirmed Ag NP presence; FTIR revealed no chemical alteration. Disk diffusion tests showed no inhibition zones. Adhesion and direct contact tests displayed antibacterial activity. The effect was superior in direct contact test. Short-term time-dependent adhesion test of one-layer coating of acrylic and silicone had a consistent decrease in bacterial amount, whilst zirconium had only a strong initial activity. In general, the three-layer coating did not reveal a higher antimicrobial activity, suggesting that the increase in layering can negatively impact surface effectiveness. Conclusions: Spray coating of Ag NPs represents a potentially feasible and relevant strategy for enhancing the antibacterial properties of dental and maxillofacial prosthetic materials without compromising their inherent physicochemical characteristics, pending further cytotoxicity and in vivo validation. Full article

The Tonglushan ore field is an important component of the polymetallic mineralization belt in the middle and lower reaches of the Yangtze River in China. The skarn-type Cu, Fe, Au, and Mo molybdenum deposits are mainly developed in the contact zone between the rock mass and the strata, as well as in the contact zone between residual and capturing bodies in the rock body. The distribution of ore bodies is controlled by faults and strata, but there is a lack of large-scale geophysical information on the contact relationship between the ore-forming geological body and the host rock and on the deep spatial morphology of the ore-forming structure and intrusion rock. The study uses the JS-WEM2 wide-field electromagnetic instrument and the RS230 spectrometer to conduct the ground frequency domain electromagnetic and radiometric spectrometry measurements on four profiles. The measurement results indicate that the fault distribution in the Tonglushan ore field is predominantly in the NW-trending and NE-trending directions. The NW-trending Tonglushan–Lijiashan fault (F2) is a steeply dipping fault; the NE-trending faults are minor, with steep dips, generally extending no deeper than −1000 m. The Tonglushan stock exhibits the northeastward uplift, characterized by southward overlap and southeastward dip. The deep resistivity is greater than 3000 Ω·m, while the resistivity below −1000 m is less than 2000 Ω·m due to the fault influence. The ore bodies are mainly distributed along the contact zones where variations in the occurrence of the rock intersect with the strata. On resistivity profiles, these zones show the gradient variation in resistivity and the distorted shape of the resistivity contour line. The radioactive element contents of wall rock above the ore bodies are characterized by high U, high Th, and low K. The Wide-Field Electromagnetic Method (WFEM) can effectively detect the distribution and morphology of rocks and faults, and combined with the radioactive characteristics of geological bodies, it can effectively identify concealed faults and the favorable mineralization target areas. Novelty: The study combines the WFEM with radiometric measurements to reduce uncertainty in exploration compared to using only one method. It improves the detection accuracy and target identification ability of deep hidden ore bodies, providing the new technical method for deep mineral exploration in complex structural areas. Full article

To identify novel field control strategies against Pyrrhalta aenescens (Coleoptera: Chrysomelidae) and provide scientific support for its biocontrol in urban tree management, this study investigated the virulence of Beauveria bassiana against this pest under laboratory conditions, as well as its physiological and biochemical effects. Bioassays using the dipping method showed that B. bassiana was pathogenic to all developmental stages of P. aenescens, with the highest virulence observed against early-instar larvae (1st and 2nd instars). For these stages, corrected mortality and mycosis rate were positively correlated with conidial concentration, and the median lethal time (LT₅₀) was the shortest. In contrast, pupae and eggs exhibited the strongest resistance to fungal infection. In leaf-disk choice tests, larvae significantly preferred untreated leaves or those treated with low concentrations of B. bassiana, displaying a concentration-dependent repellent response to the fungus. Physiological measurements revealed that larval body length and weight gain were significantly inhibited following fungal exposure. Further analysis indicated that B. bassiana infection markedly reduced total hemocyte counts and triggered intense melanization and nodulation responses, particularly in younger larvae. Overall, these results suggest that B. bassiana has strong potential for the biological control of P. aenescens. Control measures targeting early-instar larvae are recommended for cost-effective management, providing a scientific basis for developing eco-friendly control technologies based on this entomopathogenic fungus. Full article

To address the inherent drawbacks of micro-arc oxidation (MAO), this study employed MAO combined with sol–gel processing to fabricate ZrO₂/Al₂O₃-CeO₂ composite coatings on ZrH_1.8 surfaces, aiming to solve the hydrogen evolution problem of zirconium hydride (ZrH_1.8) materials in high-temperature environments. By adjusting the aluminum concentration in the sol (0.1~0.5 mol/L), a series of composite thin films were prepared on the ZrH_1.8 surface using MAO combined with dip-coating, and their surface morphology and phase composition were characterized. The microstructure, morphology, and hydrogen barrier performance of the thin films were systematically analyzed using scanning electron microscopy (SEM), XRD, laser confocal microscopy, and quadrupole mass spectrometry. The results showed that the composite coating had a low surface porosity, with a maximum hydrogen permeation reduction factor (PRF) of 18.1. When the aluminum concentration was 0.4 mol/L, the relative content of tetragonal ZrO₂ (T-ZrO₂) reached 13.88%, the surface porosity was as low as 4.87%, and the initial temperature of hydrogen loss was increased to 730 °C. Mechanism analysis indicated that CeO₂ may stabilize the tetragonal phase (T-ZrO₂) of ZrO₂ through solid solution effects and inhibit the phase transformation to monoclinic phase (M-ZrO₂), thereby reducing cracks caused by volume expansion. Meanwhile, the synergistic effect of the MAO densified layer and the sol–gel sealed porous layer significantly reduced the coating porosity and blocked hydrogen diffusion paths, thus achieving excellent hydrogen barrier performance under high-temperature conditions. Full article

Uneven energy distribution and suboptimal fragmentation in bench blasting of hard–soft interbedded rock masses are critical challenges in open-pit mining. In this study, a five-hole bench blasting numerical model is developed using the discrete element method (DEM) to systematically investigate the effects of hard ore layer position, dip angle, and thickness on blasting performance. Numerical results indicate that while hard–soft layering has limited influence on overall bench fragmentation, it strongly controls block size distribution. Hard ore layers located in the upper or lower parts of the bench tend to form concentrated zones of large blocks, whereas those in the middle part achieve more uniform fragmentation, reducing the oversized block rate by approximately 57% and 45% compared with upper and lower locations, respectively. The dip angle of hard ore layers exhibits a nonlinear effect on the oversized block rate, reaching a maximum at 20°, and layer thickness is positively correlated with large-block occurrence. Based on these findings, a refined blasting strategy for hard–soft interbedded rock masses is proposed. Numerical simulations demonstrate that introducing satellite holes and implementing staged charging reduce the oversized block rate by 13% and 36%, respectively. Field bench blasting trials further indicate that top air-deck charging is beneficial for improving fragmentation uniformity in heterogeneous rock masses. These results provide a scientific basis for optimizing bench blasting parameters under complex lithological conditions. Full article

The study analyzes a major deep-seated landslide affecting National Road 16 at KP 178+000 in the Rif region of northern Morocco, a corridor repeatedly impacted by geotechnical instability. Using historical information, detailed geological mapping, multiple field campaigns, and extensive subsurface investigations (core drilling, inclinometers), the authors characterize the site as a complex setting of metamorphosed, fractured, and altered peridotites overlain by Quaternary sediments dipping negatively toward the Mediterranean. The landslide is interpreted as deep-seated planar translational landslide and has been exacerbated by human activity, specifically the placement of excavated material on the downslope side during road upgrade works in late 2019. Inclinometer data show active movement extending to at least 20 m depth, confirming the deep-seated nature of the instability. Three remediation strategies were implemented: shifting the road alignment with terracing, combining road realignment with soil nailing and slope reprofiling, and installing large bored piles tied back with anchors, following recommendations from an external expert. The authors emphasize that robust geological investigations and properly regulated construction practices are essential to reduce landslide risk for infrastructure built in mountainous coastal regions. Full article

This case study investigates the rapid through-wall perforation of newly installed hot-dip galvanized (HDG) fire sprinkler pipes in a coastal Mediterranean environment. Failure occurred along the internal waterline of horizontal sections within a short service period. Forensic analysis—comprising metallography, SEM, and EDS—identified a synergistic atmospheric–aqueous corrosion mechanism. Marine aerosol exposure during pre-service storage led to significant chloride enrichment and localized depletion of the 40–50 μm zinc coating, initiating early-stage pitting. Upon commissioning, stagnant water established oxygen concentration gradients and differential-aeration cells, driving localized anodic dissolution. Additionally, sulfate-reducing bacteria (SRB) contributed to accelerated degradation through microbiologically influenced corrosion (MIC), as suggested by sulfur-bearing tubercles. The findings demonstrate that standard galvanizing thickness alone does not ensure longevity in high-salinity environments if atmospheric “preconditioning” occurs. These results underscore the necessity of shielding internal pipe surfaces during storage and construction to prevent premature failure. This case study informs predictive maintenance and material selection for stagnant-water systems in coastal regions. Full article

We propose a loss-managed BIC-derived GSST metasurface for robust phase-change-tunable mid-infrared transmission suppression. The metasurface consists of a SiO₂ substrate, a Si grating layer, and an upper Si/Ge₂Sb₂Se₄Te₁ (GSST)/Si trilayer with an off-centered air slot. The slot plays a dual role: it breaks the mirror symmetry of the unit cell to convert a symmetry-protected bound state in the continuum into an externally accessible high-Q resonance, while reducing the effective GSST filling region to limit material-loss participation. Lossless eigenmode analysis confirms the BIC-derived origin of the resonance, with the quality factor following $Q\propto x_{\mathrm{disp}}^{-1.993}$. A crystalline-state loss-channel analysis further identifies $x_{\mathrm{disp}}=40\mathrm{nm}$ as a finite-coupling operating point that preserves good up/down radiation balance, a large resonant amplitude factor, and a moderate-high quality factor under the fully crystalline GSST condition. Full-wave simulations show that the transmission-dip wavelength shifts from about $3.9568\mathsf{\mu }\mathrm{m}$ to about $3.9740\mathsf{\mu }\mathrm{m}$ as GSST evolves from the amorphous to the crystalline state, while the extracted quality factor remains in the range of 483–780 and the transmission minimum stays deeply suppressed throughout the phase-change trajectory. A two-port temporal coupled-mode theory analysis reveals that this persistent low-transmission state originates from destructive interference between the resonant and background transmission channels. Fabrication tolerance analysis shows that $\pm 5\%$ variations in GSST thickness and slot width, as well as moderate variations in the slot displacement, preserve the deep transmission suppression across GSST phase states, although the absolute resonance wavelength shifts with geometry. These results provide a practical strategy for balancing radiative coupling and material-loss participation in phase-change high-Q metasurfaces. Full article

This study addresses fault ride-through of doubly-fed pumped storage units by proposing switched bang–bang funnel controllers for machine- and grid-side converters. The objective is to enhance transient stability, current regulation, and DC-link voltage support during severe AC grid faults. The method combines funnel-based error constraints with a switching logic that activates a bang–bang action only when tracking errors approach prescribed performance bounds, reverting to nominal regulation otherwise. High-fidelity electromagnetic transient simulations are conducted and benchmarked against a conventional PI-based controller under three-phase-to-ground fault scenarios. The results show that the switched controller achieves faster active/reactive power recovery with reduced overshoot, markedly suppresses current oscillations on both converters, and limits DC-link voltage dips while shortening the voltage restoration time. The switched controller also prevents the pumped storage unit operating in pumping mode from becoming unstable in the case of a metallic fault scenario. These findings indicate that the proposed strategy improves dynamic performance and fault ride-through capability without compromising steady-state behavior, providing a practical pathway toward compliance with grid-code requirements for pumped storage units under severe disturbances. Full article

To balance load-bearing capacity and acoustic insulation, this study proposes a sandwich reinforced concrete (RC) slab with W-shaped interlayer inclined rebar connectors and investigates their influence on acoustic bridging. A three-dimensional vibro-acoustic finite element modeling approach was adapted to analyze airborne sound insulation and impact sound pressure levels in the frequency domain and was validated against experimental results. Parametric analyses were then conducted to evaluate the effects of connector number, connector geometry, anchorage-end treatment, and core-layer parameters. The results revealed distinct frequency-dependent behavior. The introduction of connectors produced a stable dip in airborne sound insulation near 400 Hz and a pronounced impact-sound peak within 200–400 Hz, both associated with connector-controlled coupled characteristic frequencies. Increasing the number of connectors strengthened interlayer stiffness coupling and intensified acoustic bridging in these frequency ranges. By contrast, optimizing the connector structure or introducing a compliant end layer reduced coupling and improved acoustic insulation. Overall, acoustic performance can be improved by reducing the equivalent coupling stiffness of the connectors, enhancing energy dissipation at the connector ends, and appropriately selecting the core-layer parameters. These measures help suppress the characteristic-frequency response and improve mid- to high-frequency sound insulation. Full article

A Ti-Al-Si composite coating was prepared on Ti65 titanium alloy using a two-step hot-dipping + pre-oxidation method to improve its tribological performance and high-temperature oxidation resistance. The second-step dipping time strongly affected the coating microstructure and wear behavior. The optimal coating, prepared with a dipping time of 5 min in each step, exhibited negligible wear after oxidation at 800 °C for 1000 h and 2500 h, with slight adhesive wear and oxidative wear as the dominant mechanisms. Longer dipping times led to mixed wear modes and reduced wear resistance. Under high-temperature corrosion conditions, the coating showed good long-term stability in water vapor, with its mass gain following a sub-parabolic law, Δm = 0.39·t^0.47, because the internal multilayered structure effectively blocked inward oxygen diffusion. However, in environments containing NaCl or 75 wt.% Na₂SO₄ + 25 wt.% NaCl, catastrophic hot corrosion occurred, regardless of the presence of water vapor, through a chlorine-driven oxidation–chlorination–reoxidation autocatalytic cycle. In the mixed salt environment, Na₂SO₄ decomposition supplied additional oxygen and alkaline species, accelerating the degradation and spallation of the Al₂O₃ and TiO₂ scales. Water vapor further intensified this cycle by generating HCl, which promoted rapid consumption of Al and Ti in the coating. This study reveals the wear behavior and hot corrosion failure mechanisms of Ti-Al-Si coatings under complex conditions, providing guidance for process optimization and applications in marine atmospheres. Full article

Introduction: SGLT2 inhibitors reduce renal composite endpoints and proteinuria, yet RCTs uniformly show an acute eGFR dip within 2 weeks to 2 months after initiation. However, demographic and clinical predictors of an acute eGFR dip demonstrate considerable heterogeneity across studies. This study aims to identify urinary protein biomarkers of this early eGFR dip and integrate them with routine variables to build a clinically actionable prediction model. Methods and analysis: This three-stage proteomics study includes retrospective discovery, prospective internal validation, and external validation cohorts (total n ≈ 600–700). DIA mass spectrometry will screen for urinary proteins associated with ≥10% eGFR decline at 1 month post-SGLT2i initiation in CKD stages 3–4. Top candidates (FDR < 10%, FC > 1.5, ion intensity > 1 × 10⁴, unique gene families) will be validated by ELISA. A LASSO-logistic regression model will integrate the top three proteins with seven routinely available clinical variables: age, BMI, diabetes status, heart failure, systolic blood pressure, baseline eGFR, and diuretic use. Model performance will be assessed using the C-statistic, NRI, IDI, and calibration metrics. Adaptive stopping rules are pre-specified. Ethics and dissemination: Approved by the Ethics Review Committee at Chinese PLA General Hospital (S2025-859-02, 2025KY126-KS002), all participants will provide written informed consent prior to enrollment, and the study will adhere to the Declaration of Helsinki. Data will be pseudonymized and stored securely according to institutional regulations. Findings will be published in peer-reviewed journals and presented at international nephrology conferences. Trial Registration: Registered Report Identifier: ChiCTR2600119772. Date of registration: 3 March 2026. Full article

Alginate hydrogels offer mild ionic gelation and tunable porosity for drug delivery, yet their hydrophilic, macroporous networks suffer from rapid initial burst release of water-soluble payloads. Here we introduce a hierarchical barrier-engineering strategy in which poly(D,L-lactide-co-glycolide)/poly(ethylene glycol) (PLGA/PEG) blend coatings are applied via dip-coating to Ca²⁺-cross-linked alginate beads (~1 mm) and microgels (~100 µm). For beads, three-cycle PLGA/PEG multilayer coating suppressed the initial swelling rate (dQ/dt) by ~50% and reduced 1 h burst release from >85% to ~60%, functioning as an “early-burst buffer” rather than a long-term depot. For microgels, a single PLGA/PEG layer partially attenuated burst release; however, an additional PLGA outer shell (double-barrier architecture) shifted the release-governing mechanism from swelling-dominated to diffusion-barrier-dominated control, limiting 10 min release to <10%. Core–shell formation was verified by confocal laser scanning microscopy (CLSM), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS); thermogravimetric analysis (TGA) showed ~73–79% coating retention after 9 days in phosphate-buffered saline (PBS, 37 °C). A vacuum re-loading process further improved encapsulation efficiency (>50% for beads, >20% for microgels) without compromising gel integrity. In beads, burst control was governed by swelling suppression; in microgels, the additional PLGA shell shifted control to diffusion-barrier-dominated release, demonstrating that barrier architecture must be adapted to particle scale. Full article