Search Results (1,156)

Ensuring the integrity of pavement structures necessitates a thorough evaluation of both surface-level damage and subsurface mechanical performance. This study proposes an integrated, non-destructive assessment framework tailored for semi-rigid base asphalt pavements subjected to repeated vehicular loading via MLS66 full-scale accelerated testing equipment. The proposed methodology integrates ground-penetrating radar (GPR) using the CO4080 system and dynamic response measurements from a falling weight deflectometer (FWD) to characterize structural conditions across multiple depths. Comparative analysis between pre-loading and post-loading data revealed significant deterioration trends in the surface layers, with stiffness loss closely associated with increasing load repetitions. In contrast, the underlying base layers exhibited stable deformation characteristics, with variations in deflection basin indices remaining within ±5%. Subgrade dielectric properties derived from GPR data confirmed consistent compaction quality throughout the test site. Statistical analysis further validated the synergy between GPR and FWD results, demonstrating that the combined application enhances diagnostic accuracy. The dual-method approach improved overall evaluation reliability by approximately 22–35% compared to using individual techniques alone under accelerated pavement testing scenarios. These findings support broader implementation of integrated sensing systems and highlight the potential for application across varied pavement types and loading conditions. Full article

Single-crystal diamond (SCD) is an ideal substrate material for semiconductor devices due to its extremely wide bandgap and exceptionally high thermal conductivity. However, diamond’s extreme hardness and chemical inertness pose challenges for the fabrication of ultra-smooth surfaces. Traditional polishing processes are not only inefficient but also prone to introducing subsurface defects, which severely degrade device performance. To address the above issues, this study proposes a hybrid polishing process combining reactive ion etching (RIE) surface modification with chemical mechanical polishing (CMP), which enables low-loss atomic-level processing of SCD. The study found that RIE treatment induces lattice disorder on the diamond surface, forming a sp²-hybridized amorphous carbon-modified layer. Compared to the sp³ structure of native diamond, this modified layer has lower hardness and is easier to remove. We conducted the verification of the optimized process using high-quality single-crystalline diamond (SCD) samples with an initial surface roughness Ra of 0.68 nm. Under the optimized RIE parameters (substrate bias power: 200 W, etching time: 600 s, gas flow ratio of Ar:O₂:CF₄ = 40:50:10), the surface roughness Ra was reduced to as low as 0.35 nm after 2 h of CMP treatment. Furthermore, systematic characterization of the SCD’s as-received surface, RIE-modified surface, and CMP-treated surface was performed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), elucidating the “etching modification–mechanical removal” polishing mechanism. Full article

Selecting suitable maize hybrids and appropriately increasing planting density is a crucial strategy for improving maize yield under subsurface drip irrigation. A two-year field experiment was conducted to assess the impacts of two maize hybrids (Zhengdan 958, ZD958; Jingke 968, JK968) and four planting densities of 60,000 (PD1), 75,000 (PD2), 90,000 (PD3), and 105,000 plants ha⁻¹ (PD4), on maize growth indices, ear leaf photosynthetic parameters, nitrogen content, grain yield, and yield components. The results indicated that with increasing planting density, the plant height of ZD958 initially increased and then decreased, whereas that of JK968 continued to increase. The leaf area index of both hybrids consistently increased, while stem diameter, rind puncture strength, and stalk breaking strength gradually decreased. Dry matter accumulation initially increased and then decreased, peaking at PD3. Ear leaf nitrogen content, relative chlorophyll content, net photosynthetic rate, and stomatal conductance all decreased with increasing planting density, while intrinsic water use efficiency (iWUE) first increased and then declined, reaching its maximum at PD3. Notably, iWUE of JK968 was significantly higher than that of ZD958 during the dough stage (p < 0.01). Ear traits, including ear length, ear diameter, kernels per ear, and grain weight per ear, all decreased continuously with increasing planting density. Grain yield followed a unimodal curve, peaking at the PD3 treatment, with two-year average yields of 12.7 and 13.5 t ha⁻¹ for ZD958 and JK968, respectively. JK968 exhibited significantly higher leaf area index, stem diameter, rind puncture strength, stalk breaking strength, ear length, kernels per ear, grain weight per ear, and grain yield compared to ZD958 (p < 0.01), demonstrating superior tolerance to high planting density and enhanced source–sink coordination. In conclusion, in the North China Plain, JK968 planted at a density of 90,000 plants ha⁻¹ can synergistically optimize population structure, improve stalk mechanical strength, and enhance photosynthetic efficiency, under subsurface drip irrigation. Full article

Bridge decks are continuously subjected to high environmental exposure, traffic loading, and material aging, leading to progressive delamination which can negatively affect structural integrity and public safety. More specifically, subsurface delamination of concrete and corroded steel reinforcement must be repaired to keep the decks operational. Among non-destructive evaluation techniques, Ground-Penetrating Radar (GPR) and Infrared Thermography (IRT) offer complementary capabilities for detecting subsurface and near-surface defects; however, effective GPR-IRT data fusion remains challenging due to fundamental differences in sensing principles, spatial resolution and sensitivity. This study introduces a Physics-Enhanced Multi-Modal Fusion (PE-MMF) framework that integrates GPR and IRT data to improve delamination detection in reinforced concrete bridge decks. The proposed approach leverages transfer learning, cross-modal attention mechanisms, and gated fusion to enable robust learning from heterogeneous sensor inputs. Furthermore, a systematic feature selection protocol is integrated to identify physically meaningful indicators that remain consistent across different bridges, enhancing generalization capability. The framework is trained and validated using the publicly available SDNET2021 dataset, comprising co-registered GPR and IRT measurements from five in-service bridge decks with verified delamination ground truth. Results demonstrate substantial performance improvements, with average F1-score gains of up to 55% over IRT-based methods and 25% over GPR-based methods across all tested bridges. Comparative analysis against state-of-the-art methods confirmed the superior generalization capability of the proposed multi-modal approach over single-modality approaches. The findings highlight the potential of deep learning-based sensor fusion as a scalable and data-efficient decision-support tool to prioritize regions for detailed physical investigation during long-term infrastructure monitoring. Full article

This study presents the diagnostic and conservation work carried out on the Roman mosaic of the South cubiculum in the Latomia dei Niccolini (Marsala, western Sicily). The mosaic, decorated with polychrome tesserae featuring a kantharos motif, presented severe structural damage, including fractures, subsurface voids, and progressive material loss. To assess the causes of deterioration and design an effective conservation strategy, an integrated approach combining non-invasive geophysical and 3D survey methods was applied. Ground-penetrating radar (GPR) was selected as the main diagnostic tool because it allows high-resolution subsurface imaging while preserving the integrity of the fragile mosaic surface. By utilizing high-frequency 2 GHz antennas and complementary video inspection, a significant subsurface cavity beneath the mosaic preparation layer was successfully mapped, determining its critical relationship with the main diagonal surface fracture. Simultaneously, laser scanning and close-range photogrammetry enabled the creation of accurate 3D models supporting both documentation and restoration planning. The conservation concluded with surface cleaning, mortar consolidation, and the successful structural detachment and relocation of the compromised section onto a lightweight support for future museum display. The findings demonstrate that integrating 3D digital and geophysical data provides a quantitative, low-risk roadmap for preserving highly vulnerable archaeological floorings, moving beyond qualitative technical documentation to establish a replicable preservation framework. Full article

China regards shale gas as a key energy source for ensuring energy security, promoting the transformation of the energy structure, and addressing climate change. However, at this stage, the scarcity of land resources, coupled with various institutional restrictions, has brought numerous practical obstacles to the large-scale commercial development of shale gas. By analyzing the restrictive provisions concerning shale gas development in China’s current laws, this paper points out three major institutional constraints faced by the use of agricultural land for shale gas development: first, stringent land use control policies; second, the legal acquisition system for surface land remains unstable; third, institutional gaps in the supervision of subsurface space on collectively owned land. To overcome these institutional barriers, this study proposes fundamental reform measures for the current land legal framework. If comprehensive reform cannot be achieved immediately, partial breakthroughs may be sought within the existing institutional framework. The sequence has three phases. Near-term one to three years: negative-list quotas, refined land classification, land linkage, benefit balance, and community guidance. No law changes needed; provinces can act. Medium-term three to seven years: regulations and the mining land chapter in the revised Mineral Resources Law. Long-term beyond seven years: constitutional amendment for collective land transfer and dual-track supply reform. This study provides a theoretical reference for solving the land use issues in China’s shale gas development, and its conclusions also provide a reference for resolving the conflicts between shale gas development and agricultural land use in other jurisdictions. Full article

Talus slopes and scree deposits connect rockwall sediment supply, gravitational transport, footslope storage, hydrothermal conditions, and mountain hazards, yet their literature is distributed across several disciplines. This study develops a manually refined bibliometric dataset to clarify the knowledge structure and thematic evolution of talus slope geomorphology. We retrieved 971 records from the Web of Science (WoS) Core Collection, including the Science Citation Index-Expanded (SCI-EXPANDED) and Social Science Citation Index (SSCI) databases, manually screened their geomorphic relevance, excluded records from the incomplete publication year 2026, and analyzed 548 articles and reviews published during 1966–2025. Bibliometrix and Biblioshiny analyses show sustained publication growth, especially after 2006, and an intellectual base combining slope-process geomorphology, paraglacial and periglacial research, geophysical investigation, and hazard studies. Standardized Author Keywords indicate increasing attention to permafrost environment, subsurface detection, multi-source monitoring, and slope hazards. These indexed patterns support a synthesis of talus slopes as dynamic source-transport-storage systems, while the WoS-only coverage and manual refinement steps define the study’s evidential limits. Full article

This study investigates the oxidation behavior and microstructural evolution of Sanicro 25 steel (X7NiCrWCuCoNb25-23-3-3-2) after long-term exposure to water vapor at 700 °C for 30,000 h. Particular attention was paid to the relationship between protective oxide-scale formation, chromium depletion in the near-surface region, and the possible changes in secondary-phase stability in the steel substrate. FIB-SEM tomography was applied to characterize the oxide scale and the underlying affected zone, enabling three-dimensional visualization of oxide morphology, interfacial voids, and microstructural reconstruction beneath the scale. Long-term exposure resulted in the formation of a continuous Cr-rich oxide scale with a thickness of approximately 2.6 µm and local Mn enrichment. The scale exhibited a complex multilayered morphology, consisting of outer Cr-rich oxide crystallites, fine-grained chromium oxides, and an inner heterogeneous Mn-enriched region, suggesting the possible formation of mixed spinel-type oxides. Si-enriched regions were observed near the oxide/metal interface; however, no continuous Si oxide layer was detected. Despite the presence of interfacial voids, no scale spallation was observed in the investigated regions. SEM-EDX analysis revealed a chromium-depleted subsurface zone extending to approximately 6.5 µm below the oxide scale. CALPHAD calculations suggest that local chromium depletion may reduce the thermodynamic stability of Cr-rich M₂₃C₆ carbides and the Nb–Cr–N-type Z phase. This possible reduction in phase stability may contribute to the formation of a precipitate-depleted region and local microstructural reconstruction beneath the oxide scale. In the bulk region, where oxidation effects were negligible, the microstructure consisted of an austenitic matrix containing M₂₃C₆ carbides, σ phase, Cr–Ni–Fe nitride with an A13-type structure, ε-Cu precipitates, Z phase, and W-rich Cu-containing TCP precipitates. The simulations further suggest that most secondary phases form during the early stage of annealing, whereas prolonged exposure is dominated by diffusion-controlled coarsening. Overall, Sanicro 25 shows good resistance to long-term steam oxidation at 700 °C due to the formation of a continuous Cr-rich protective scale. However, this protection is accompanied by chromium depletion and local near-surface microstructural changes, which should be considered when assessing the long-term stability and service performance of this steel under high-temperature steam conditions. Full article

Laser hard overlaying is an advanced, perspective technology with wide industrial applications, for example, dies. The aim is to improve surface properties like wear resistance using special layers of powder sintered or remelted by laser beam. At present, dies are manufactured by machining with following bulk heat treatment, which is an expensive process particularly due to use of expensive high-alloyed tool steels. Repairs performed using arc or plasma welding introduce a big amount of heat to the part, which can cause dimension changes and material degradation. These methods often fail also due to low weldability of the materials. An advantage of laser overlaying is minimization of these difficulties. The paper contains a comprehensive evaluation of several types of hard overlayed powder of H13 tool steel on a S355 structural steel and on H11 tool steel using a laser beam. Macro- and microstructure, hardness and fatigue resistance are evaluated, including fatigue damage mechanisms. In the case of the H13 welds on the S355 steel plate, the quality of the welds was mostly acceptable, without pores or segregate impurities and with a good interconnection between the weld track and base material. Results are completed with basic measurement of residual stresses using destructive strain-gauge methods. High tensile residual stresses of 1465 MPa were measured at the boundary of the first track of the single-layer overlay. Fatigue resistance is sensitive on surface and subsurface defects, which can significantly reduce endurance limit. Fatigue strength of specimens with the single layer overlay was considerably lower than fatigue strength of the S355 steel. The decrease was between 25% and 50%. In the case of overlay of H13 on H11 tool steel, the decrease in fatigue strength was between 25% and 30%. Full article

This review presents a process-based decision-making framework for chlorinated vapor intrusion (CVI) mitigation. CVI mitigation refers to the set of engineered strategies aimed at interrupting, attenuating or transforming vapor fluxes before they reach indoor environments. Existing literature and technical guidelines typically classify mitigation strategies according to technological configuration (active versus passive), rather than physical and chemical processes governing vapor transport and attenuation, which may lead to suboptimal design choices and reduced system resilience. To address this limitation, this framework proposes a process-based classification of CVI mitigation strategies based on the dominant mechanisms controlling vapor migration in subsurface. Five mechanistic categories are identified: driving-force control through pressure manipulation, dilution via air exchange, diffusive flux control through physical barriers, density-driven attenuation in permeable sub-slab layers, and in situ transformation based on sorption or degradation. By explicitly linking mitigation technologies to transport and transformation processes, the proposed framework provides a structured basis for mechanism-oriented selection, integrating performance, longevity, climate resilience, and lifecycle energy demand. In addition to established mitigation approaches, such as sub-slab depressurization, this work highlights emerging passive strategies, including high permeable granular layers and horizontal reactive or adsorbing barriers, as potential low-energy alternatives for durable management. Overall, the proposed framework supports site-specific, sustainability-oriented decision-making on CVI mitigation. Full article

Karst critical zones in Southwest China are highly vulnerable to soil–water loss because thin soils, exposed carbonate bedrock, well-developed epikarst, and strong surface–subsurface connectivity promote both surface erosion and subsurface leakage. Although soil erosion, subsurface leakage, karst rocky desertification, and ecological restoration have been widely studied, the coupling between landscape structural patterns and soil–water loss remains insufficiently synthesized. This semi-systematic critical review synthesizes evidence from karst hydrology, soil erosion, karst rocky desertification, landscape structure, and critical zone studies, with a primary focus on Southwest China. The reviewed evidence indicates that geomorphic setting, land use vegetation structure, bare-rock exposure, and epikarst development jointly regulate runoff generation, infiltration, sediment detachment, subsurface leakage, and sediment connectivity. Peak–cluster depressions commonly favor internal sediment storage and vertical leakage, whereas valley and canyon systems tend to enhance surface runoff connectivity and channelized sediment export. However, pathway dominance varies with rainfall intensity, soil moisture, soil thickness, land use, karst rocky desertification degree, and fracture–conduit connectivity. Long-term soil–water loss may further reshape landscape structure through soil thinning, vegetation degradation, bedrock exposure, and karst rocky desertification feedbacks. Current research is limited by insufficient quantification of subsurface soil loss, weak integration between landscape metrics and hydrological models, and scarce long-term monitoring data. Future studies should integrate field monitoring, tracers, remote sensing, landscape metrics, and coupled surface–subsurface models to support geomorphic-setting-specific karst rocky desertification control. Full article

The ablation behavior of 2.5D C/SiC composites under continuous-wave laser irradiation involves not only surface material removal but also internal structural degradation. In this study, laser ablation tests were conducted at power densities of 400, 800, and 1600 W/cm², and the ablated specimens were analyzed by macroscopic observation, infrared thermography, X-ray micro-computed tomography (micro-CT), cross-sectional scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), depth measurement, and homogeneous thermal-field simulation. The results show that the surface morphology evolved from a transition-zone-dominated response to a typical zoned morphology consisting of a central ablation zone, transition zone, and edge zone as the power density and irradiation time increased. Under the present temperature measurement conditions, the surface transition zone corresponded to an apparent temperature window of approximately 2300–2700 K. Cross-sectional characterization further revealed a distinguishable internal reaction front beneath the external ablation surface, above which microstructural damage and Si depletion were observed. Depth measurements showed that the external ablation depth underestimated the actual degradation depth along the thickness direction. The calibrated homogeneous thermal-field model indicated that the internal front position corresponded to a relatively stable temperature range, suggesting that its formation was mainly governed by local thermal history and matrix-related reactions. The proposed internal reaction front provides a supplementary parameter for evaluating laser-induced subsurface degradation in 2.5D C/SiC composites. Full article

Initial carious lesions represent a reversible stage of the caries process in which non-operative strategies can prevent lesion progression and preserve dental hard tissues. This comprehensive review provides an overview of peptide-based approaches for the management of initial carious lesions, with emphasis on self-assembling peptides. The literature was identified through PubMed electronic searches complemented by manual screening of reference lists. Only randomized clinical trials and controlled clinical studies published in English were included. The PICOS framework guided the structure of the review, focusing on patients of any age with initial carious lesions, peptide-based interventions aimed at enamel remineralization, comparisons with placebo, alternative treatments, or standard preventive care (e.g., fluoride products), and outcomes related to de-/remineralisation. Overall, the available evidence suggests that peptide-based strategies can mimic natural biomineralization and promote subsurface hydroxyapatite formation. Among the investigated approaches, the self-assembling peptide P11-4 is the most extensively studied. Evidence supports its safety and its potential to enhance initial carious lesion remineralisation, with possible advantages over fluoride alone in selected cases. In conclusion, peptide-based potentially regenerative approaches, particularly P11-4, represent a promising adjunct in minimally invasive caries management, although further long-term and comparative clinical studies are needed to define their role in routine dental practice. Full article

The Marmara region of Türkiye, situated along the North Anatolian Fault Zone (NAFZ), constitutes one of the most seismically active and densely monitored zones globally. Given the region’s high vulnerability and the catastrophic impacts of historical events—notably the 1999 İzmit and 2023 Kahramanmara¸s sequences—there is a critical need for advanced seismic hazard risk assessment (SHRA) methods that move beyond static models. This review examines the paradigm shift from traditional geophysics to big data seismology, characterized by the “Five Vs”: volume, velocity, variety, veracity, and value. Critically, we distinguish between two fundamentally different problems: Earthquake Early Warning (EEW), which operates on sub-second timescales after rupture initiation, and probabilistic earthquake forecasting, which operates on timescales of years to decades. The study discusses how cloud-native platforms such as Azure Databricks, combined with data pipelines using Apache Kafka (version 3.5.1) and Apache Spark (version 4.1.2), enable the real-time processing of petabyte-scale seismic sensor streams. Key technological tools, including Physics-Informed Neural Networks (PINNs) and deep learning models such as PhaseNet, are analyzed for their demonstrated ability to enhance EEW systems through sub-second phase picking and automated event detection. Seismic tomography is also undergoing AI-enabled transformation, yielding higher-resolution subsurface imaging. We present statistical validation metrics and uncertainty quantification methods essential for credible hazard assessment. By addressing computational bottlenecks through hybrid computing architectures and edge computing, this framework aims to improve the warning lead time for Istanbul’s critical infrastructure. This work provides a structured roadmap for bridging the gap between traditional seismic data analysis and operational predictive analytics in the Marmara region. Full article

The detection and degradation analysis of subsurface microcracks in mural paintings remain challenging due to their inhomogeneous multilayered structure and complex deterioration mechanisms. In this study, we propose a multimodal stepwise method for three-dimensional characterization and cross-scale degradation analysis by integrating digital holography (DH), infrared thermography (IRT), acoustic excitation (AE), and molecular dynamics (MD) simulations. In the first step, an adjustable field-of-view (FOV) digital holographic system is developed to capture subsurface deformation under acoustic excitation, enabling high-resolution planar characterization of subsurface microcracks. Infrared thermography is then employed to estimate crack depth through an inverse thermal model, achieving full three-dimensional reconstruction of crack geometry. Based on the reconstructed structures, MD simulations are conducted to investigate the evolution of stress, bond breaking, and crack propagation under varying temperature and humidity conditions, with particular emphasis on water molecule migration and chemically induced degradation. The results demonstrate that environmental factors promote stress concentration and material embrittlement at crack tips, leading to secondary microcrack formation and progressive deterioration. Experimental aging tests show strong agreement with simulation results, validating the proposed methodology. This work establishes a unified “characterization–simulation–validation” paradigm, providing new insights into the mechanisms of mural degradation and offering a robust framework for non-destructive evaluation and preventive conservation of multilayer cultural heritage materials. Full article