Search Results (4,850)

Cracks in civil infrastructure exhibit large variations in appearance due to differences in surface texture, illumination, and background clutter, making reliable segmentation a challenging task. To address this issue, this paper proposes an adaptive Mixture-of-Experts (MoE) framework that combines multiple crack segmentation models based on their estimated reliability for each input image. A lightweight gating network is trained using out-of-fold soft supervision to learn how to rank and select the most suitable experts under varying conditions. During inference, only the top two experts are combined to produce the final segmentation result. The proposed framework is evaluated on two public datasets—Crack500 and the CrackForest Dataset (CFD)—and one in-house dataset (RCFD). Experimental results demonstrate consistent improvements over individual models and recent state-of-the-art methods, achieving up to 2.4% higher IoU and 2.1% higher F1-score compared to the strongest single expert. These results show that adaptive expert selection provides an effective and practical solution for robust crack segmentation across diverse real-world scenarios. Full article

This work investigates the structural, acoustic, and thermo-oxidative degradation behavior of elastomeric composites made from neat EPDM and recycled devulcanized EPDM (EPDMd) blends, both with and without silica (SiO₂). SiO₂ plays a complex role in degradation, possibly acting as a catalyst and also affecting the properties of the materials. Samples were subjected to accelerated degradation at 80 °C for 30 days. The characterization included the mechanical, spectroscopical (FTIR-ATR), thermal (TGA), and morphological (SEM) studies of the samples. Given EPDM’s use in construction as a sound-absorber, its acoustic properties were also analyzed. The determination of the mechanical properties shows that the incorporation of SiO₂ improves the Young’s modulus (YM), maintains the tensile strength (TS) at similar values, and causes a decrease in elongation at break (EB). The content of EPDMd slightly decreases both the TS and the EB and increases the YM. The thermo-oxidative degradation of the studied composites does not affect the TS values, but it increases the YM for the samples with and without SiO₂ for EPDMd contents higher than 40 phr, and decreases the EB for samples with and without SiO₂ for all EPDMd contents. The FTIR-ATR, TGA, and SEM results show that the addition of SiO₂ catalyzes the thermo-oxidative degradation process, while the EPDMd inhibits structural degradation. Migration of the ZnSt₂ included in the formulations to the surface is common in these elastomers. In this case, EPDMd forms microaggregates, which retain the exudation of ZnSt₂ crystals, especially in the non-degraded samples. The degraded samples present irregular structures, with microcavities, cracks, and occlusions, which increase the acoustic absorption mainly at frequencies below 1500 Hz. Full article

Forming tools adjustable by tensile elastic deformations offer opportunities for improved process control and reduced wear in high-volume metal forming processes such as ironing. However, the lack of tensile and fatigue data for hardened cold-work tool steels limits their broader adoption. This study investigates the mechanical performance of three tool steels—Vanadis^®4 Extra SuperClean, Vancron^® SuperClean, and Caldie^®—through uniaxial tensile and fatigue testing, supplemented by destructive static and fatigue/wear tests on specimens representative of an adjustable ironing punch. Non-coated specimens exhibited ultimate tensile strengths above 2700 MPa with approximately 2% plastic strain, while coated specimens fractured in a brittle manner between 1600–1900 MPa. Fatigue life at stress ranges between 1450–1750 MPa varied from several thousand to over four million cycles, with crack initiation linked to non-metallic inclusions and precipitates 10–30 $\mathsf{\mu }$m in size. Finite element simulations accurately linked failure observed in uniaxial tests to the component-level tests, confirming that first principal stress is a reliable predictor for punch failure. All punch specimens withstood ${10}^6$ cycles at diameter changes up to 140 $\mathsf{\mu }$m (4‰), with coated punches exhibiting minimal wear and non-coated ones showing localized surface damage. The findings support material and coating selection for adjustable forming tools and highlight opportunities for further optimization. Full article

Silicon oxide/graphite (SiO_x/Gr) anodes are promising candidates for high energy-density lithium-ion batteries. However, their complex multiphysics degradation mechanisms pose challenges for accurately interpreting and predicting capacity fade behavior. In particular, existing multiphysics models typically treat gas generation and solid electrolyte interphase (SEI) growth as independent or unidirectionally coupled processes, neglecting their bidirectional interactions. Here, we develop an electro–thermal–mechanical–gaseous coupled model to capture the dominant degradation processes in SiO_x/Gr anodes, including SEI growth, gas generation, SEI formation on cracks, and particle fracture. Model validation shows that the proposed framework can accurately reproduce voltage responses under various currents and temperatures, as well as capacity fade under different thermal and mechanical conditions. Based on this validated model, a mechanistic analysis reveals two key findings: (1) Gas generation and SEI growth are bidirectionally coupled. SEI growth induces gas release, while accumulated gas in turn regulates subsequent SEI evolution by promoting SEI formation through hindered mass transfer and suppressing it through reduced active surface area. (2) Crack propagation within particles is jointly governed by the magnitude and duration of stress. High-rate discharges produce large but transient stresses that restrict crack growth, while prolonged stresses at low rates promote crack propagation and more severe structural degradation. This study provides new insights into the coupled degradation mechanisms of SiO_x/Gr anodes, offering guidance for performance optimization and structural design to extend battery cycle life. Full article

Transparent conductive oxides (TCOs), such as indium tin oxide (ITO), are essential for flexible electronics; however, conventional vacuum-based deposition is costly and thermally aggressive for polymers. This study investigated the surface functionalization of PET substrates with ITO thin film-based forced hydrolysis as a low-cost, reproducible alternative. $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ nanoparticles were synthesized by forced hydrolysis at 180 °C for 3 h and 6 h, yielding crystalline nanoparticles with a cassiterite phase and an average crystallite size of 20.34 nm. The process showed high reproducibility, enabling consistent structural properties without complex equipment or high-temperature treatments. The $\mathrm{S}\mathrm{n}{\mathrm{O}}_2$ sample obtained at 3 h was incorporated into commercial ${\mathrm{I}\mathrm{n}}_2{\mathrm{O}}_3$ to form a mixed In–Sn–O oxide, which was subsequently deposited onto PET substrates by spin coating onto UV-activated PET. The resulting 1.1 µm ITO films demonstrated good adhesion (4B according to ASTM D3359), a low resistivity of 1.27 × 10⁻⁶ Ω·m, and an average optical transmittance of 80% in the visible range. Although their resistivity is higher than vacuum-processed films, this route provides a superior balance of mechanical robustness, featuring a hardness of (H) of 3.8 GPa and an elastic modulus (E) of 110 GPa. These results highlight forced hydrolysis as a reproducible route for producing ITO/PET thin films. The thickness was strategically optimized to act as a structural buffer, preventing crack propagation during bending. Forced hydrolysis-driven PET sheet functionalization is an effective route for producing durable ITO/PET electrodes that are suitable for flexible sensors and solar cells. Full article

Crack detection plays a pivotal role in ensuring the safety and stability of infrastructure. Despite advancements in deep learning-based image analysis, accurately capturing multiscale crack features in complex environments remains challenging. These challenges arise from several factors, including the presence of cracks with varying sizes, shapes, and orientations, as well as the influence of environmental conditions such as lighting variations, surface textures, and noise. This study introduces DAH-YOLO (Dynamic-Attention-Haar-YOLO), an innovative model that integrates dynamic convolution, an attention-enhanced dynamic detection head, and Haar wavelet down-sampling to address these challenges. First, dynamic convolution is integrated into the YOLOv8 framework to adaptively capture complex crack features while simultaneously reducing computational complexity. Second, an attention-enhanced dynamic detection head is introduced to refine the model’s ability to focus on crack regions, facilitating the detection of cracks with varying scales and morphologies. Third, a Haar wavelet down-sampling layer is employed to preserve fine-grained crack details, enhancing the recognition of subtle and intricate cracks. Experimental results on three public datasets demonstrate that DAH-YOLO outperforms baseline models and state-of-the-art crack detection methods in terms of precision, recall, and mean average precision, while maintaining low computational complexity. Our findings provide a robust, efficient solution for automated crack detection, which has been successfully applied in real-world engineering scenarios with favorable outcomes, advancing the development of intelligent structural health monitoring. Full article

8Cr4Mo4V bearing steel is a critical material for main shaft bearings in aero-engine applications. However, the current understanding of the micro-mechanical properties of its matrix and primary carbide phases (vanadium-rich and molybdenum-rich carbides) remains insufficient. This knowledge gap readily induces various forms of deformation damage during grinding, severely compromising the surface integrity of the workpiece. To address this, nanoindentation and nano-scratch techniques were employed to systematically quantify the micro-mechanical properties of each phase and investigate the deformation damage behavior of the steel under load. Results showed that MC carbides exhibited the highest elastic modulus and microhardness, which made them more susceptible to becoming crack initiation sites during grinding. Nano-scratch testing further revealed that crack initiation at carbide edges and localized spalling were the primary damage mechanisms. This study provides a micro-mechanical foundation for controlling the grinding surface quality of 8Cr4Mo4V bearing steel, holding significant implications for optimizing grinding processes, suppressing crack initiation, and elucidating the grinding damage mechanism. Full article

Low-density polyethylene (LDPE) and poly (butylene adipate-co-terephthalate) (PBAT) agricultural films are major components of microplastics (MPs) and their contamination in agriculture due to their difficulty to recycle. However, potential degradation mechanisms of MPs from LDPE and PBAT in agricultural soils are still unclear. Here, we isolated a strain of Bacillus cereus L6 from long-term agricultural MP-contaminated soil and analyzed its potential biochemical pathways involved in LDPE and PBAT turnover through functional prediction from shotgun genome sequencing. After 28 days of incubation with MPs, Bacillus cereus L6 caused a net mass loss of 0.99% LDPE-MPs/28 days and 3.58% PBAT-MPs/28 days. The surfaces of LDPE and PBAT degraded in bioassays added with Bacillus cereus L6 showed wrinkles, cracks, and pits, accompanied by an increase in roughness. The crystallinity and thermal stability of both LDPE- and PBAT-MPs were decreased and the hydrophobicity of PBAT-MPs was reduced. Whole-genome sequencing analysis showed that Bacillus cereus L6 potentially encoded genes for enzymes related to the biodeterioration of additives in LDPE and PBAT. Moreover, genomic CAZymes predictive analysis showed that genes related to oxygenases and lyases were annotated in the strain L6 Auxiliary Activities family. These findings offer a theoretical foundation for deeper exploration into the degradation and metabolic processes of MPs from discarded agricultural plastics in the environment. Full article

Double-shell ZnO/Al₂O₃ submicron hollow fibers were successfully fabricated through a combined electrospinning and atomic layer deposition (ALD) approach. Polyvinyl alcohol (PVA) fibers were first produced by electrospinning and subsequently coated with a conformal Al₂O₃ barrier layer via low-temperature ALD employing trimethylaluminum (TMA) and deionized (DI) H₂O to preserve the integrity of the temperature-sensitive polymer core. The inner polymer was then removed using two different techniques—thermal annealing and water dissolution—to compare their effects on the fiber morphology. Finally, a functional ZnO layer was deposited by thermal ALD with diethylzinc (DEZ) and DI H₂O. It was found that the polymer removal method critically determined the final structural and morphological characteristics of the fibers. Thermal annealing resulted in smooth, shrunken fibers, while water dissolution led to diameter expansion and the formation of a highly rough, bubble-like surface structure due to swelling-induced micro-cracking. The selection of the polymer removal method offers a precise and controllable route for tailoring the fiber morphology. The resulting high-aspect-ratio (HAR) structures, particularly the rough and expanded fibers, exhibit enhanced specific surface area, making them highly promising for applications in sensing, catalysis, and filtration. Full article

Three common agricultural beneficial microbes, Trichoderma harzianum, Bacillus cereus, and Pseudomonas fluorescens, are widely used in the growth cycle of crops, and increase the yield of agricultural products through disease prevention and sterilization. As a biodegradable biological macromolecular material, polylactic acid (PLA) is also widely used in agricultural production as a biodegradable film. The addition of agricultural microbes will affect the degradation rate of polylactic acid and thus its agricultural use. Under specific conditions (Tri15), the degradation rate of PLA film exceeds 30%. Scanning electron microscopy (SEM) images show that the degradation of the PLA happened after 360 days of exposure to these three specific microbe environments, which makes the surface of PLA films crack. Gel permeation chromatography (GPC) analysis reveals that in the presence of these microbes, the molecular weight of PLA is reduced. The analysis of 16S rDNA sequences demonstrates that the introduction of these microbes alters the soil microbial community, resulting in an enhanced abundance of Betaproteomicrobes, promoting the degradation of PLA. These results indicate that the three microbes species significantly promote the degradation of PLA, and the effects of microbes vary for the different concentrations. This study establishes practical guidelines for the deployment of PLA in real-world farmland environments. Full article

Epoxy asphalt, as a thermosetting material, has received increasing attention due to its outstanding mechanical properties and durability. However, its insufficient low-temperature resistance, limited toughness, and relatively high material cost still restrict its large-scale application in pavement engineering. To improve its low-temperature performance and reduce construction costs, this study investigates the low-temperature behavior of epoxy asphalt modified with desulfurized crumb rubber. In this study, a functional additive, hereafter referred to as WJFL (a laboratory-designated organic disulfide-based rubber plasticizer), was incorporated during the preparation of the desulfurized rubber–asphalt binder to enhance the curing rate of the modified epoxy asphalt. The addition of WJFL promotes the devulcanization and activation of rubber powder, enhancing the overall performance of the modified epoxy asphalt. When the desulfurized rubber content is 20%, WJFL additive dosage is 2%, and asphalt content is 300% of epoxy resin mass, the modified epoxy asphalt not only meets the specification requirements but also exhibits excellent low-temperature crack resistance and improved economic efficiency. The addition of crumb rubber increased tensile strength by 15.38% and elongation at break by 17.24%. Furthermore, WJFL additive increased tensile strength by 80% and elongation at break by 25% when WJFL content was increased from 0% to 2%. Additionally, optimizing the asphalt-to-epoxy ratio, with asphalt content increased from 100% to 300%, resulted in an 80% increase in tensile strength and a 28.57% improvement in elongation at break. Moreover, desulfurized crumb rubber modification enhanced the low-temperature stiffness modulus, highlighting better performance in cold regions. Relaxation tests conducted at −10 °C, −15 °C, −20 °C, and −25 °C show that the modified epoxy asphalt has significant potential for use in pavement surfacing, particularly in cold climates. Full article

Regenerative hardfacing of steel substrates is an important technology for restoring the surface layer of components operating under wear conditions, supporting the goals of the circular economy (CE) by extending the service life of components, reducing material and energy consumption throughout their life cycle, and shortening downtime during machine repairs. The article provides a synthetic analysis of the literature on the production of functional layers exclusively on steels and systematizes process → structure → properties (PSP) relationships in the context of technological quality and the prediction of the functional properties of welds. The review covers methods used and developed in steel hardfacing (including arc processes and variants with increased energy concentration), analyzed on the basis of measurable process indicators: energy parameters (arc energy/heat input/volume energy), dilution, bead geometry, heat-affected zone characteristics, and the risk of welding defects. It has been shown that these factors determine the structural effects in the weld and the area at the fusion boundary (including phase composition and morphology, hardness gradient, and susceptibility to cracking), which translates into functional properties (hardness, wear resistance, adhesion, and fatigue life) and durability after regeneration. The main result of the work is the development of a PSP table dedicated to hardfacing on steel substrates, mapping the key “levers” of the process to structural consequences and trends in functional properties. This facilitates the identification of optimization directions (minimization of energy input and dilution while ensuring fusion continuity), which translates into longer durability after regeneration and a lower risk of defects—key, measurable effects of CE. Research gaps have also been identified regarding the comparability of results (standardization of energy metrics) and the need to determine and verify “technology windows” within the WPS/WPQR (welding procedure specification/welding procedure qualification record) for layers deposited on steels. Full article

Stone cultural relics are primarily composed of sandstone, a water-sensitive rock that is highly susceptible to deterioration from environmental solutions and dry-wet cycles. Sandstone pagodas are often directly exposed to natural elements, posing significant risks to their preservation. Therefore, it is crucial to investigate the performance of sandstone towers in complex solution environments and understand the degradation mechanisms influenced by multiple environmental factors. This paper focuses on the twin towers of the Huachi Stone Statue in Qingyang City, Gansu Province, China, analyzing the changes in chemical composition, surface/microstructure, physical properties, and mechanical characteristics of sandstone under the combined effects of various solutions and dry-wet cycles. The results indicate that distilled water has the least effect on the mineral composition of sandstone, while a 5% Na₂SO₄ solution can induce the formation of gypsum (CaSO₄·2H₂O). An acidic solution, such as sulfuric acid, significantly dissolves calcite and diopside, leading to an increase in gypsum diffraction peaks. Additionally, an alkaline solution (sodium hydroxide) slightly hydrolyzes quartz and albite, promoting calcite precipitation. The composite solution demonstrates a synergistic ion effect when mixed with various single solutions. Microstructural examinations reveal that sandstone experiences only minor pulverization in distilled water. In contrast, the acidic solution causes micro-cracks and particle shedding, while the alkaline solution results in layered spalling of the sandstone surface. A salt solution leads to salt frost formation and pore crystallization, with the composite solution of sodium hydroxide and 5% Na₂SO₄ demonstrating the most severe deterioration. The sandstone is covered with salt frost and spalling, exhibiting honeycomb pores and interlaced crystal structures. From a physical and mechanical perspective, as dry-wet cycles increase, the water absorption and porosity of the sandstone initially decrease slightly before increasing, while the longitudinal wave velocity and uniaxial compressive strength continually decline. In summary, the composite solution of NaOH and 5% Na₂SO₄ results in the most significant deterioration of sandstone, whereas distilled water has the least impact. The combined effects of acidic/alkaline and salt solutions generally exacerbate sandstone damage more than individual solutions. This study offers insights into the regional deterioration characteristics of the Huachi Stone Statue Twin Towers and lays the groundwork for disease control and preventive preservation of sandstone cultural relics in similar climatic and geological contexts. Full article

Cracking occurred in the surface coating of a screw rotor during shale gas well operations. To determine whether the coating cracks could contribute to the failure of the 42CrMo substrate, the microstructure and morphology of surface cracks and local corrosion pits were examined and analyzed using a metallographic microscope, an SEM, and an EDS. To investigate the cross-sectional morphology and elemental distribution of corrosion pits, EDS mapping was performed. The composition of the corrosion products was characterized using Raman spectroscopy and XPS. In addition, four-point bend stress corrosion tests were conducted on screw rotor specimens under simulated service conditions. The results indicate that the P and S contents in the screw rotor substrate exceeded the specified limits, whereas its tensile and impact strengths satisfied the standard requirements. The microstructure consisted of tempered sorbite and ferrite, along with a small amount of sulfide inclusions. The corrosion products on the fracture surface were primarily identified as FeOOH, Fe₃O₄, and Cr(OH)₃. All specimens failed during the four-point bend tests. The chlorine (Cl) content in the corroded regions reached up to 8.05%. These findings demonstrate that the crack resistance of the 42CrMo screw rotor was markedly reduced under the simulated service conditions of 130 °C in a saturated, oxygenated 25% CaCl₂ solution. The study concludes that stress concentration induced by sulfide inclusions in the screw rotor, together with the combined effects of chloride ions, dissolved oxygen, and applied load, promotes the initiation and propagation of stress corrosion cracking. Therefore, it is recommended to strictly control the chemical composition and inclusion content of the screw rotor material and to reduce the oxygen content of the drilling fluid, thereby mitigating the risk of corrosion-induced cracking of the rotor. Full article

In this study, the influence of the electrochemical oxidation process on Ti-Grad 23 alloy (Ti6Al4V ELI) in 1 M H₃PO₄, under applied voltages between 200 and 275 V, at a constant time of 1 min, is analyzed. The structural, morphological, and wettability properties of the TiO₂ anodic layers obtained were investigated by X-ray diffraction (XRD), energy dispersive electron microscopy (SEM-EDS), contact angle measurements, and chemical corrosion. XRD analysis showed the development and intensification of anatase and brookite phases, with increased crystallite size after electrochemical oxidation. SEM/EDS characterization confirmed the formation of an inhomogeneous porous TiO₂ layer, with pore diameters ranging from 98 to 139 nm and a significant increase in oxygen content. Contact angle measurements demonstrate enhanced hydrophilicity for all oxidized samples, with progressively lower values as the applied voltage increased. Chemical corrosion tests in Ringer solution and Ringer + 40 g/L H₂O₂ indicated that oxidized surfaces maintain structural stability in physiological media, whereas exposure to oxidizing environments induces partial pore closure and crack formation due to localized corrosion. The optimal anodizing condition was identified at 200 V for 1 min, yielding a uniform distribution of pores and improved morpho-functional characteristics suitable for biomedical applications. The optimal electrochemical oxidation conditions were identified at 200 V for 1 min, ensuring a uniform pore distribution. Full article