Search Results (480)

Silver (Ag)-based conductive coatings are widely used in electrical contacts due to their excellent electrical conductivity, low contact resistance, good thermal stability and oxidation resistance, although their susceptibility to sulfidation and environmental corrosion is a concern under certain service conditions. In recent years, significant progress has been achieved in both the manufacture and performance optimization of Ag-based coatings to satisfy the demanding requirements of modern electrical and electronic systems. This review summarizes recent advances in fabrication techniques and processing parameters for Ag-based coatings, including electroplating, electroless deposition, magnetron sputtering, electrospark deposition, thermal spraying, and electrical explosion spraying on metallic substrates, particularly on copper and steel substrates. More attention is given to microstructural design strategies, such as the incorporation and homogeneous dispersion of reinforcement or solid lubricant phases within the Ag matrix, to enhance contact reliability and operational endurance. The performance of Ag-based coatings is analyzed in terms of their physical, chemical and mechanical properties, electrical contact resistance, friction and wear behavior, arc erosion resistance, and environmental durability under different service conditions. Key challenges, including coating degradation under high electrical loads, mechanical wear, and corrosive environments, are highlighted. Future research directions are outlined, focusing on multifunctional coating structures that enhance surface performance and ensure the long-term durability of electrical contacts. Full article

Background and Objectives: This study aimed to investigate the prevalence and severity of dental erosion using the Basic Erosive Wear Examination (BEWE) index in an adult cohort, exploring its associations with systemic health, gastrointestinal symptoms, and dietary habits. Materials and Methods: An observational cross-sectional study was conducted with 170 adult patients at a university clinic in Cluj-Napoca, Romania, between January and June 2026. Participants completed a standardized questionnaire detailing general characteristics, diet, systemic conditions, and symptoms. Dental erosion was clinically recorded via the highest BEWE score per sextant. Chairside tests evaluated unstimulated salivary pH and buffering capacity. Data were analyzed using chi-square tests and ordinal logistic regression. Results: Most patients exhibited low BEWE risk. Bivariate analyses revealed significant associations between elevated BEWE risk and advanced age, GERD, eating disorders, and carbonated beverage consumption. However, in the adjusted ordinal logistic regression model, only advanced age, GERD, digestive symptoms (difficulty swallowing, digestive burns), and specific medications (anti-asthma drugs, aspirin) remained independent predictors of increased erosive wear risk. Conclusions: Dental erosion is a multifactorial condition strongly shaped by advanced age, GERD, eating disorders, and carbonated beverage intake. A comprehensive risk-based approach incorporating medical histories, symptom screening, and dietary counseling is essential for early clinical identification and prevention. Full article

Hydrophobic and superhydrophobic coatings have attracted considerable attention due to their ability to provide water repellency, self-cleaning, anti-corrosion, anti-icing, and anti-fouling properties, making them promising for a wide range of industrial applications. This review summarizes recent advances in the development of hydrophobic and superhydrophobic coatings, with particular emphasis on wetting mechanisms, material selection, coating formation approaches, durability issues, commercial implementation, and environmental aspects. The analysis examines the principal classes of materials used for coating fabrication, including polymeric materials, inorganic compounds, and composite systems. The mechanisms responsible for the formation of hydrophobic and superhydrophobic surfaces are discussed in terms of surface chemistry modification and hierarchical roughness generation. Attention is devoted to factors limiting long-term performance, such as mechanical wear, chemical degradation, ultraviolet exposure, climatic effects, hydrodynamic erosion, and adhesion-related failures, as well as to current strategies for improving durability. Commercially available technologies and their application areas are reviewed, and the environmental challenges associated with fluorinated compounds are considered. The analysis demonstrates that the combination of controlled surface morphology and reduced surface energy remains an effective approach for achieving durable hydrophobicity, with optimized coating systems reaching contact angles of 160–170° and retaining superhydrophobic properties for more than 500 h under demanding operating conditions. Future developments are expected to focus on environmentally friendly, multifunctional, and long-lasting coating systems. Full article

Developing Cu-based composites with excellent electrical and mechanical properties under multiphysics-coupled service conditions remains challenging. Novel Cu-Nb-Gr composites were fabricated by high-energy ball milling and High-pressure Multi-field Assisted Rapid Sintering. Experiments combined with computational fluid dynamics (CFD) and finite element method (FEM) simulations were used to investigate how Gr regulates material performance. The incorporation of 3 vol.% Gr promoted the formation of a semi-continuous Gr-rich structure coupled with an Nb-rich load-bearing structure. Under arc erosion, the semi-continuous Gr-rich structure provided efficient heat-conduction pathways, reducing the peak temperature and metal-vapor recoil force, while the Nb-rich load-bearing structure suppressed liquid–metal spattering and stabilized the molten pool. Simultaneously, Gr dynamically spread to form a continuous solid-lubricating film during sliding friction, significantly reducing the coefficient of friction and interfacial shear stress. Furthermore, under compressive loading, the semi-continuous Gr-rich structure coupled with the Nb-rich load-bearing structure alleviated interfacial elastic–modulus mismatch and extreme stress concentration, limiting macroscopic plastic deformation of the matrix. Consequently, Cu-Nb-3Gr achieved a favorable balance of arc-erosion resistance, wear resistance, and compressive performance, providing a new strategy for improving conventional Cu-based composites. Full article

In salt cavern compressed air energy storage (CAES) systems, slag particles entrained by high-pressure airflow can cause pipeline wear and flow instability, posing challenges to long-term operational safety. However, direct experimental studies are constrained by high-pressure, large-scale conditions and transient multiphase flow complexities. This study uses Fluent, a numerical simulation method based on gas–solid two-phase flow theory, to investigate the flow characteristics, particle dynamics, and erosion behavior in the above-ground pipeline of CAES system. Results reveal uneven gas velocity distribution, with the lowest flow (≤2.3 (m/s)) in the main pipeline favoring particle deposition, and complex vortex structures at branch connections. Particles accumulate on the outer wall of 90° elbows due to centrifugal effects, leading to localized erosion, with severe wear occurring at impact angles of 20–30°. Over a 30-year operational cycle, the predicted maximum wear depth is 0.38 mm, which remains below the existing protective cladding thickness of 0.5 mm. The findings not only provide a theoretical basis and design insights for optimizing wear protection strategies, but also hold positive implications for enhancing the economic sustainability and environmental benefits of large-scale energy storage systems. Full article

The influence of guide-vane leading-edge profiles on interstage flow, particle transport, and erosion in multistage deep-sea mining pumps remains unclear. This study compares Convex, Linear, and Concave profiles in a two-stage pump using an Euler–Lagrange framework coupled with the Finnie erosion model. Hydraulic performance, pressure recovery, mainstream-flow organization, and particle transport were analysed at the design flow rate, whereas erosion characteristics were further evaluated over flow rates of 0.68Q–1.33Q and particle volume concentrations of 6–10%. At the design flow rate, the total head and overall hydraulic efficiency of the two-stage pump with the Concave profile reached 87.10 m and 53.32%, respectively. The Concave profile produced smoother pressure recovery, lower turbulent kinetic energy, and mainstream-flow ratios of 63.3% and 69.0% downstream of the first- and second-stage guide vanes, respectively. In the first-stage leading-edge region, its average particle mass concentration was 6.42% and 33.84% lower than those of the Convex and Linear profiles, respectively, demonstrating that the Concave profile effectively reduced particle accumulation near the guide-vane leading edge. In contrast, the Convex profile exhibited interstage erosion amplification, whereas erosion for the Linear profile was concentrated mainly in the first stage. Erosion increased with both flow rate and particle concentration for all profiles. Overall, the Concave profile provided the best balance among hydraulic performance, reduced particle accumulation, and predicted erosion resistance. Full article

To address the problem of the short service life of relay injection molds caused by erosion of high-temperature glass fibers, AlCrN coatings were deposited on the surface of ELMAX mold steel using multi-arc ion plating technology. The surface morphology, cross-sectional morphology, and elemental composition of the coatings were analyzed using scanning electron microscopy (SEM) and the attached energy-dispersive X-ray spectroscopy (EDS). The phase structure was characterized by X-ray diffraction (XRD). The surface hardness, film–substrate adhesion strength, and friction and wear performance were tested using a nanoindenter, a scratch tester, and a friction and wear tester, respectively. The effects of duty cycle, arc current, and negative bias voltage on the coating microstructure, hardness, adhesion strength, and friction and wear performance were systematically investigated. Increasing the duty cycle increases surface particles and pits but improves coating density; increasing the arc current increases coating thickness but coarsens particles; increasing the negative bias voltage refines particles but increases pits. Through a three-factor, three-level orthogonal experiment and a multi-index equal-weight weighting method, with hardness, adhesion strength, and friction coefficient as comprehensive evaluation objectives, the optimal process parameters were determined as a duty cycle of 70%, an arc current of 60 A, and a negative bias voltage of 110 V. The optimized coating achieved a hardness of 36.04 GPa (399% higher than that of the uncoated substrate), an adhesion strength of 143.87 N, and a friction coefficient of 0.422. In production cycle tests, the coated mold exhibited an average service life of 128,070 cycles, which is 277% higher than that of the uncoated mold (33,985 cycles). The surface of the coated mold showed only slight scratches, while the uncoated mold exhibited severe glass-fiber plowing grooves. This study provides a process optimization and verification solution for extending the service life of injection molds. Full article

As a critical component of electric railways, catenary systems are prone to cracks, loosening, corrosion, and wear under long-term vibration, fatigue, and environmental erosion. However, ambiguous fault boundaries, large inter-component variations, and tiny defects severely hinder reliable anomaly detection and condition assessment. To address these challenges, this paper proposes a vision-based intelligent fault assessment framework for railway catenary components based on a novel Railway Diffusion-based Anomaly Detection (Rail-DiffAD) model. Specifically, Rail-DiffAD combines residual feature mapping, a Multi-scale Partial Convolutional Spatial-Channel Attention (MPSCA) module with Log-Barrier Bi-directional Constraint Loss (LBBCL), and conditional diffusion-based distribution modeling to achieve robust anomaly localization in complex industrial scenarios. Furthermore, a severity-aware diffusion representation is introduced to characterize structural defect evolution, and a multi-physics fault assessment framework integrating mechanical response, corrosion evolution, and stress concentration analysis is established for quantitative fault grading and maintenance decision-making. Experiments on a real catenary dataset covering 10 component categories demonstrate that the proposed framework achieves a 0.953 image-level AUROC and a 0.957 pixel-level AUROC, outperforming existing methods while maintaining strong cross-component generalization and providing quantitative fault grading support for intelligent railway catenary maintenance. Full article

To reveal the wear mechanisms of high-temperature metallic materials under particle erosion, this study investigated TP347 steel using a single-particle erosion–oxidation in situ system, off-axis digital holographic microscopy (DHM), granular erosion testing, and finite element modelling. Compared with conventional ex situ SEM or 3D profilometry, DHM provides crater-scale three-dimensional quantification of pit mouth diameter, crater depth, and crater volume. Under single-particle impact at 400 °C, the crater morphology changed from a wide and shallow profile at 30° to a deeper and more symmetric indentation at 90°, while the fitted velocity exponent increased from approximately 0.36 to 0.94 with increasing impact angle. Under normal impact, increasing the pre-oxidation temperature from 400 to 600 °C increased oxide-film thickness and crater depth and strengthened the velocity dependence of erosion. Granular erosion showed a staged process in which initial oxide-film removal was followed by a more stable substrate-involved erosion stage after the accumulated erodent mass approached 60 g. Finite element results reproduced the transition from tangential-shear-dominated damage at low angles to normal-impact-induced plastic indentation and oxide-film cracking at high angles. These results clarify the coupled role of impact angle, velocity, temperature, and oxide-film response in the high-temperature erosion behavior of TP347 steel. Full article

This study addresses the operational challenges of developing hard-to-recover reserves such as heavy-oil rims in weakly consolidated sandstone reservoirs of Western Siberia, which account for a significant share of Russia’s resource base. The core challenge is the inevitable solid production during extraction, leading to abrasive wear, erosion, plugging of downhole pumping equipment, frequent failures, and substantial economic losses. The objective of this work is a comprehensive analysis of the causes of sand production and related equipment failures by integrating published research with field failure data. The research methodology includes an analysis of scientific publications and a statistical review of the causes and frequency of Electrical Submersible Pump (ESP) failures in wells produced by the PK formation. The results show that the primary failure causes are erosive wear (predominantly in medium-rate deviated wells) and plugging by produced solids (predominantly in low-rate horizontal wells), which correlate with sand transport regimes and the particle size distribution (PSD) of produced solids. The failure frequency was found to be comparable across different well types, but the equipment damage mechanisms differed significantly. The discussion confirms the necessity for an integrated approach to modeling the “reservoir–sand control screen–wellbore” system to optimize operating parameters and select effective sand control techniques. Full article

Background and Objectives: In-office bleaching is one of the most requested aesthetic procedures, but its biomechanical aftermath on enamel—particularly the recovery trajectory of microhardness, surface roughness, and erosive vulnerability—remains incompletely characterised. The present study quantified the 28-day mechanical recovery profile of enamel after three commonly used chairside bleaching protocols and examined inter-relationships between mechanical, topographic and erosive endpoints. Methods: Forty-two human molars and premolars (27 molars, 15 premolars) extracted for clinical reasons and previously catalogued in the institutional biobank were sectioned along the cervical–occlusal axis to obtain matched control and experimental halves. The experimental halves were assigned (n = 14 per group) to Opalescence Quick (45% carbamide peroxide, no light), Opalescence Boost (40% hydrogen peroxide, chemically activated), or BlancOne Ultra+ (35% hydrogen peroxide with light activation). Vickers microhardness (VHN), profilometric roughness (Ra), and erosive wear after a standardised citric-acid challenge were measured at baseline, immediately post-bleaching, and at 24 h, 7 d, 14 d, and 28 d in artificial saliva. Wilcoxon signed-rank, Kruskal–Wallis with Dunn–Bonferroni post hoc, linear mixed-effects models, multiple linear regression, ROC analysis, and Spearman correlations were used (α = 0.05). Results: Immediate VHN drops were −13.2 ± 3.9%, −22.6 ± 3.6%, and −29.6 ± 4.7% for Opalescence Quick, Opalescence Boost, and BlancOne Ultra+, respectively. By 28 days, recovery reached 97.4 ± 2.2%, 96.0 ± 2.9%, and 91.6 ± 2.3% of baseline (p < 0.001). Exponential rate constants were 0.137, 0.075, and 0.092 d⁻¹. Erosive wear after acid challenge was 2.1×, 2.8×, and 3.8× control values. ROC analysis identified Δ-immediate Ra as the strongest predictor of incomplete recovery (AUC = 0.859). Conclusions: Higher-aggression protocols delayed mechanical recovery and amplified erosive susceptibility, with light-activated systems carrying the greatest residual risk. These in vitro findings provide an evidence base for the design of future clinical studies on post-bleaching enamel recovery and remineralisation. Full article

Asphalt pavement wearing courses are directly exposed to hydrodynamic scouring, fuel erosion, freeze–thaw action, and traffic abrasion, leading to accelerated surface deterioration, skid-resistance loss, frequent maintenance, and increased life-cycle carbon emissions. To address these challenges, this study developed an organosilicon-based erosion- and skid-resistant asphalt wearing course (OES-AWC) through a stepwise material design strategy. An organosilicon-treated asphalt concrete matrix was first prepared to improve resistance to moisture damage, fuel erosion, and ice adhesion, and its curing behavior and optimal dosage were determined. A skid-resistant surface layer was then designed by optimizing the anti-skid aggregate type, organosilicon-to-aggregate ratio, and surface texture. Finally, waterborne epoxy resin was introduced to enhance aggregate anchorage, and the integrated OES-AWC was evaluated in terms of abrasion durability, rutting resistance, long-term skid resistance, and life-cycle impacts. The results show that organosilicon treatment forms a hydrophobic siloxane network, which improves the moisture damage, fuel erosion, and anti-icing resistance of asphalt concrete by 22.0–41.1%. Emery aggregates and the optimized surface structure enhance friction stability, while waterborne epoxy resin significantly suppresses aggregate stripping under repeated wheel loading. Compared with conventional asphalt wearing courses, the optimized OES-AWC increased wear durability by 148.1% while maintaining stable skid resistance under prolonged abrasion. Life-cycle assessment further demonstrates that OES-AWC can reduce carbon emissions by 47.2% and overall costs by 25.0%, with a probability exceeding 90% according to the uncertainty analysis. These findings indicate that OES-AWC provides a durable, low-carbon, and cost-effective maintenance strategy for asphalt pavements exposed to complex service environments. Full article

Background/Objectives: In vitro simulation of dental wear is essential for preclinical evaluation of dental materials, but available devices differ widely in operating principles and simulated oral conditions. This scoping review mapped devices used to reproduce dental wear and oral aging and classified them according to the dominant wear mechanism. Methods: Searches were conducted in PubMed/MEDLINE, Scopus, Web of Science Core Collection, Embase, and Google Scholar for records published between 1985 and 2026. Eligible sources reported an identifiable in vitro device or setup, a dental material or hard-tissue substrate, and extractable device-level data on operating principles, parameters, environment, antagonist, or outcomes. Results: Sixty-eight reports were retained and consolidated into 19 devices or device families. The systems included two-body chewing simulators, three-body wear machines, robotic or multiaxial masticatory platforms, tribometers, toothbrushing abrasion devices, erosion and pH-cycling systems, tribocorrosion setups, and multifunctional oral aging simulators. Device development showed a transition from mainly mechanical wear testing toward integrated platforms combining load, sliding, thermocycling, saliva or electrolyte exposure, pH control, chemical challenge, biofilm-related conditions, and electrochemical monitoring. Reporting remained heterogeneous, particularly for load, cycle number, frequency, sliding distance, antagonist material, medium, temperature, pH, and outcome measurement. Conclusions: Device selection should be based on the dominant wear mechanism, material type, and research objective. More complete source-level reporting is needed to improve reproducibility and comparability. Full article

This study presents a computational analysis of degradation caused by cavitation and hydro-abrasive erosion in a low-head axial microturbine ($H=4\mathrm{m}$), incorporating strategic air injection as a passive mitigation technique. Using Computational Fluid Dynamics (CFD) within ANSYS CFX 2025 R2, the study investigates hydrodynamic performance and the spatial distribution of surface wear across the runner blades. The turbine geometry was developed from aerofoil profiles mapped onto cylindrical coordinates, using a structured three-dimensional mesh with localized refinement to ensure grid independence. Physical modeling employed the Shear Stress Transport (SST) turbulence model, with cavitation dynamics governed by the Rayleigh–Plesset equation and sediment transport modeled using a Lagrangian framework incorporating the Finnie erosion model. The numerical framework showed good agreement with reference characteristic curves, confirming its predictive accuracy. The results indicate that vapor cavities form predominantly on the suction side, whereas solid particle erosion highly concentrated on the pressure side of the blades, where the outer $20\%$ of the span accounts for over $91\%$ of the total erosion intensity. Parametric assessments of controlled air injection revealed a highly non-linear mitigation response, identifying IAVF 2 as the optimal air-injection case. This configuration reduced integrated erosion by $0.95\%$ and maximum localized erosion by $6.17\%$. In contrast, excessive air volumes accelerated material removal due to localized flow distortion. The findings indicate that carefully controlled air injection is a viable strategy for extending the operational lifespan of small-scale hydropower assets. Full article

The dust extraction impeller is a core component of the vehicle engine auxiliary system that filters dust from the intake air to ensure stable engine operation; its reliability directly affects the performance and operational safety of the vehicle. Critically, the dust extraction impeller can exhibit severe erosion wear in extreme environments, but conventional degradation testing methods are costly and require considerable time to complete. Therefore, this study conducted accelerated degradation testing using the change in impeller blade thickness as the degradation indicator and the dust concentration and impeller rotational speed as dual elevated stress factors to obtain time-series degradation data from 48 blade samples. Linear, exponential, power-law, natural logarithmic, and Gompertz models were subsequently fit to the data for a single sample, and then the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method was employed to select the optimal degradation trajectory model. The accuracy of the selected linear model was verified using the data from all samples, confirming that it can be applied to predict the degradation of the dust extraction impeller over time. The contribution of this study comprises the establishment of a degradation assessment framework combining accelerated degradation testing with TOPSIS-based model selection to provide a practical basis for the reliability design and maintenance planning of vehicle dust extraction impellers operating in extreme environments. Full article