Search Results (88)

During multi-layer winding of hoisting steel wire ropes for ultra-deep vertical shafts on double broken-line drums, abnormal winding behaviors such as rope interlocking, rope jumping and disordered rope arrangement may occur, accelerating abrasion and wire breakage, reducing load-bearing capacity and service life, and compromising operational safety. A dynamic rope-jumping discrimination approach considering transverse-vibration-induced fleet-angle variation was developed and evaluated through field tests. Meanwhile, based on the spatial trajectory model of multi-layer wound hoisting steel wire ropes and a quantitative criterion for rope interlocking, the effects of key drum structural parameters on rope interlocking were investigated. Results show that the broken-line zone is the main high-risk region for rope jumping, with the rightmost position of the third layer after the second-to-third-layer transition being the most critical location. Transverse rope vibration increases the fleet angle, and rope jumping occurs when the critical threshold is exceeded. At the three representative winding positions, the relative errors between the calculated and measured fleet angles are below 7.0%, and the predicted high-risk rope-jumping location is consistent with the field observation, providing field-based support for the model under the examined operating condition. Rope-interlocking risk is significantly higher in the broken-line zone and increases with larger fleet angles, smaller rope groove clearance coefficients and larger drum-to-rope diameter ratios. Full article

As a core component of carbon capture, utilization and storage (CCUS), CO₂ geological storage is critical to China’s carbon neutrality strategy. However, current assessments of China’s CO₂ geological storage potential suffer from substantial numerical discrepancies, and single evaluation methods lack sufficient reliability, constraining the scientific formulation of national CCUS planning. Addressing these deficiencies, this study proposes a comprehensive evaluation framework to integrate multi-source results and derive a robust quantitative range of national CO₂ storage potential. A weighted calculation method covering four criterion layers and 15 evaluation factors is developed in this work. From four perspectives of data authority, temporal validity, methodological reliability and regional comprehensiveness, nine representative evaluation datasets are systematically scored to determine their respective comprehensive weights. Combined with the weighted average model, China’s national CO₂ geological storage potential is quantified at 1786–2669 Gt. This multi-source fusion result avoids the inherent limitations of single-method evaluation. This study achieves the effective integration of heterogeneous multi-source evaluation data, resolving the inconsistency in existing national potential assessments. The estimate, while robust under the present validation, remains subject to inherent uncertainties and should therefore be interpreted with due caution in supporting CCUS decision-making. Full article

Weakly nonlinear free-surface flows past disturbances are traditionally modeled using the forced Korteweg–de Vries (fKdV) equation with a prescribed instantaneous pressure field. However, physical wake responses possess finite relaxation times and advection scales that diagnostic algebraic closures fail to capture. This paper introduces a novel coupled system in which the surface pressure is a dynamical field governed by an advection–reaction–diffusion equation driven by band-limited curvature. Using linear spectral theory and numerical validation, we derive a phase-speed criterion demonstrating that energy transfer is determined by the comparison between the pressure drift speed and the surface phase speed. A sharp stability theorem proves that, to leading order in the coupling strength and for a non-negative even response transfer function whose drift speed exceeds the Froude detuning, the system is spectrally stable if and only if the response is band-limited below a critical wavenumber $k_c$. Furthermore, an exact energy identity establishes that passivity and linear stability are equivalent. Finally, we demonstrate resonance steering: while coupling typically increases the wave resistance for monotone spectra, tuning the response to a spectral zero of a multi-lobe footprint reduces the drag significantly relative to its classical value. This result identifies an explicit performance–strongness trade-off, providing a mathematically strong structure for wave drag minimization through dynamic pressure control. Full article

Existing readiness indices for Connected and Automated Vehicles (CAVs) produce a single composite score per city. This conflates use cases with very different territorial requirements and, being compensatory, allows strong performance on one criterion to mask a deficiency that is, in practice, a hard prerequisite. This paper proposes and demonstrates an assessment framework with four elements. First, the verdict is stratified by Operational Design Domain (ODD) profile, so that one territory yields one verdict per use case. Second, each profile is assessed only on its eligible service area, the roads on which the corresponding service could actually operate. Third, a non-compensatory veto layer is overlaid on a compensatory segment-level score, which separates the readiness score from the fit share, the proportion of network length that satisfies every critical threshold. Fourth, the diagnosis is extended to specific corridors through a readiness-aware routing formulation. The framework is demonstrated on the Versailles, Satory, and Velizy perimeter of about 92 square kilometes, using a real OpenStreetMap network of 4834 nodes and 733 kilometres, combined with an explicitly illustrative synthetic indicator calibration. Restricting each profile to its service area changes one verdict outright. The campus shuttle and urban robotaxi profiles obtain near-identical scores, both close to 0.51, but fit shares differing seven-fold, a distinction that a single score cannot express. Readiness-aware routing reroutes up to 42 percent of origin and destination pairs onto better-equipped itineraries for about 1 percent additional travel length. Monte Carlo analysis and cross-method tests using TOPSIS and PROMETHEE-II leave all verdicts unchanged. We position the work as a methodological demonstration rather than a validated deployment tool: the indicator values are synthetic, and empirical calibration, expert weight elicitation, and field validation remain prerequisites for operational use. Full article

Transport infrastructure constitutes an essential component of the built environment, supporting urban accessibility, economic activity, and the long-term functionality of cities and developed areas. The quality of newly constructed pavements is traditionally assessed through compliance with construction specifications, such as layer thickness, material properties, and compaction requirements. However, these parameters do not directly quantify the influence of construction deviations on long-term pavement structural performance. This paper presents a structural capacity-based framework for pavement construction quality assessment that evaluates construction quality according to its expected impact on pavement service life. The proposed methodology integrates ground-penetrating radar measurements, core sampling, laboratory testing, and mechanistic structural analysis to determine the actual structural capacity of the as-built pavement expressed as the allowable number of Design Axle Loads. Based on these results, the Pavement Construction Quality Index (PCQI) is introduced to quantify the combined effects of systematic and localized construction deficiencies. To prevent severe localized defects from being masked by area-weighted averaging, the Critical Local Defect Indicator (CLDI) is proposed as an independent acceptance criterion. The sensitivity parameters of the PCQI formulation were calibrated using mechanistic analysis and HDM-4 deterioration modelling. The proposed framework was demonstrated through a real pavement reconstruction case study and further examined using Monte Carlo simulation to investigate its numerical behaviour over a broad range of construction non-compliance scenarios. The results demonstrate that the proposed methodology provides a continuous and technically consistent evaluation of pavement construction quality while enabling practical engineering interpretation of different quality levels. The framework offers a structured quantitative decision-support tool for pavement acceptance based on structural capacity rather than solely on compliance with construction tolerances, thereby supporting more reliable management of transport infrastructure as part of the wider built environment. Full article

Electricity theft remains a critical threat to power distribution infrastructure globally, with annual losses exceeding USD 89 billion and non-technical loss rates reaching 40% in developing economies. While machine learning has emerged as the dominant analytical approach for automated theft detection in smart grid environments, the field lacks a unifying framework that connects algorithm selection to the operational realities of Distribution System Operators (DSOs). Existing reviews catalogue methods and report benchmark metrics without addressing how detection paradigm selection should be aligned with data maturity, regulatory requirements, computational constraints, and institutional capacity. This review addresses that gap by systematically analysing 90 peer-reviewed studies published between 2015 and 2025, identified through structured multi-database searches, screened against explicit eligibility criteria, and graded with a formal five-criterion quality rubric, through a unified adversarial time-series formulation that provides a consistent analytical lens across all major learning paradigms. The analysis covers supervised ensemble methods, unsupervised and semi-supervised anomaly detection, deep learning architectures, including convolutional neural networks, long short-term memory networks and Transformer models, graph neural networks, federated learning, and explainable artificial intelligence. Key findings reveal that no single paradigm achieves optimality across all deployment dimensions simultaneously, that gradient boosting methods deliver near state-of-the-art performance with significantly lower computational overhead than deep learning, and that hybrid architectures achieve AUC-ROC scores of 0.95 to 0.98 on benchmark datasets but require complementary governance mechanisms to satisfy regulatory defensibility requirements. A lifecycle-aligned deployment framework and a layered detection architecture are proposed, offering practitioners a structured pathway from early AMI rollout through to advanced smart grid deployment. The principal outcomes of the review are a formal characterisation of which component of the detection problem each learning paradigm estimates, quality-graded and harmonised benchmark performance ranges, and a quantified illustrative analysis indicating that the proposed layered architecture can improve inspection productivity by roughly an order of magnitude at a fixed field budget. Four priority research challenges are identified: real-time edge detection, continual learning, multi-modal data fusion, and standardised benchmarking. Full article

Marine concrete structures are subjected to multiple aggressive ions that react with hydration products, driving dynamic phase evolution and altering ion transport pathways. This study develops a multi-scale lattice diffusion–reaction coupled framework grounded in a microstructural evolution model, incorporating a simplified analytical correction for the electrical double layer (EDL) effect. Validation against Poisson–Boltzmann numerical solutions across a pore size range of 1.5–50 nm confirms that the mean relative errors for monovalent, divalent, and trivalent ions remain within 10%. The phase evolution of cement paste under single-ion attack was simulated, and its impact on ion transport performance under multi-ion coupled ingress was systematically investigated. Under multi-ion attack, solid phases exhibit a highly ordered spatial zonation. Chloride ions completely displace monosulfate, forming a Friedel’s salt-enriched zone. Meanwhile, directly penetrating external sulfate generates a pronounced surface ettringite peak, while sulfate released from monosulfate decomposition in the Friedel’s salt zone induces secondary ettringite precipitation deeper within the material, producing a characteristic double-step ettringite distribution. A cracking criterion based on the critical capillary pore filling fraction captures the transition from pore filling to microcracking, yielding a three-zone profile for the relative diffusion coefficient. At 500 days of exposure, crystallization-induced microcracking triggers a more than 7-fold increase in surface relative diffusivity ($w/c$ = 0.35). Furthermore, at 250 days, once cracking initiates, low water-to-cement ratio ($w/c$ = 0.3) matrices display a higher relative diffusivity amplification factor of approximately 9, compared to approximately 6 for high water-to-cement ratio ($w/c$ = 0.4) matrices. The established framework provides a quantitative tool for assessing the durability of concrete structures under complex chemical attack environments. Full article

Background/Objectives: Oral solid dosage forms of traditional Chinese and ethnic medicines are currently undergoing modernisation. The objective of this study is to explore the scope for formulation variation arising from batch-to-batch fluctuations in intermediates, and to identify the factors influencing key quality attributes of honey-containing tablets. In this regard, a machine-learning-based predictive model is being formulated that will integrate and analyse formulation factors and the results characterised by the SeDeM expert system. Utilising the SeDeM index as a mediating variable, the study endeavours to establish a comprehensible and predictable stepwise research pathway to provide a foundation for industrial-scale upscaling. Methods: Twelve SeDeM expert systems were utilised to characterise honey-containing granules for formulation screening, to evaluate their suitability for use in traditional Chinese medicine honey-containing tablet systems, and to identify key limiting factors and the feasibility space affecting the quality of the final product; Based on the QBD philosophy, a TriAD (Tri-criterion Adaptive Design) design scheme was proposed, integrating the horizontal balance of orthogonal designs, the spatial coverage of uniform designs, and the parameter estimation efficiency of D-optimal designs into the experimental layout of the formulation feasibility space; Through further data aggregation, a multi-layer feature set comprising four formulation factors, six SeDeM indicators, and three critical quality attributes (CQAs) was constructed. The mediating effects of the SeDeM indicators were revealed through different pathways involving 37 combinations of simple, linear, and Bootstrap models. Furthermore, 180 linear and non-linear machine learning models (comprising 12 categories of algorithms) were trained to predict formulation and CQA outcomes, ultimately completing the design space mapping and validation. Results: The results show that the SeDeM parameters effectively bridge the CQA results of different honey formulations, with these indicators acting as selective mediators between formulation factors and CQAs. Compared with a pure data model relying solely on raw formulation variables, the introduction of SeDeM knowledge, combined with high-information-content samples obtained via TriAD, improved the predictive performance and robustness of the SeDeM–ML hybrid model in terms of disintegration time and hardness; its R²_LOO increased by 0.267 and 0.510, respectively, and the overall predictive space was significantly expanded. Experimental validation was conducted using formulations within the design space predicted by the optimal model; the results showed that both the prediction bias and the relative standard deviation were less than 5 percent. Conclusions: The present study demonstrates that SeDeM can not only be used to evaluate formulations of honey-containing TCM tablets but also serves as an intermediary bridge linking formulation factors, granule-mechanism variables, and tablet quality outcomes. TriAD, in turn, further translates the QbD philosophy into an actionable formulation space design, thereby providing a development pathway for honey-containing tablets that combines interpretability, predictability, and QbD consistency, and offers new insights for the industrial application of oral TCM preparations. Full article

To accurately reveal the mechanism of interlayer separation, crack propagation, and progressive instability of vault strata in underground cavities in gentle-dipping bedded rock masses, this paper systematically elucidates the entire mechanical behavior of separation evolution, crack penetration, structural transformation, and step-by-step caving of vault bedded rock masses under excavation disturbance through a comprehensive integration of excavation unloading mechanical analysis, the Griffith strength criterion, and the dynamic transformation theory of beam structures. The results show that excavation induces radial unloading and circumferential stress concentration in the surrounding rock, and the vault rock mass preferentially undergoes interlayer separation along near-horizontal gentle-dipping bedding planes, forming a spatial zoning feature of gradient attenuation from bottom to top: a strong separation zone at the lower part, a transition zone in the middle, and a closed zone at the upper part. The vault strata undergo a cyclic dynamic structural transformation of cantilever beam–fixed-end beam–simply supported beam, exhibiting stepped fracturing and layer-by-layer caving failure characteristics. The fracture and caving range follow a three-stage evolution law of initial increase–peak–subsequent convergence and stabilization. Based on the elastic mechanics stress transformation relationship, a Griffith initiation criterion for surrounding rock of circular cavities under non-axisymmetric loads is derived and established, and mechanical calculation models of single beam and composite beam suitable for stratified rock masses are constructed, which quantitatively reveal the controlling effects of tensile strength of strata, lateral pressure coefficient, tunnel diameter, stratification thickness, and burial depth on crack initiation and failure degree. Verified by a city-gate-shaped tunnel numerical test and an practical engineering case of a large-scale underground tunnel in western China, the theoretical calculation results are in good agreement with the on-site failure morphology and numerical analysis results. The established separation criterion and mechanical model can effectively predict the initiation risk and stability critical conditions of vault strata. The research results can provide a theoretical basis and technical support for the stability evaluation, early warning, and optimal design of support structures of surrounding rock in underground engineering in gentle-dipping bedded rock masses. Full article

Ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) are physically complementary non-destructive evaluation methods for reinforced concrete, yet their integrated diagnostic use has been limited by the absence of controlled, ground-truth-validated calibration of the joint-signature space. This paper presents a laboratory calibration programme in which a single C30/37 reinforced concrete beam (3000 mm × 300 mm × 200 mm, three T12 bars at 35 mm cover, CEM I 42.5N, w/c = 0.50) was sequentially conditioned through four controlled deterioration states—intact reference (Model A), water-filled saw-cut crack (Model B), full saturation by seven-day top-surface ponding (Model C), and chloride-induced active corrosion (Model D). Seven RES2DINV inverted ERT sections at three electrode spacings (a = 7, 15, and 30 mm) and three 800 MHz GPR profiles were acquired across the four known ground-truth conditions. The intact-reference resistivity ρ₀ = 558 Ω·m (full-section median of the mlab dataset at a = 7 mm) and GPR-calibrated velocity v = 0.095 ± 0.008 m/ns (from hyperbola fitting at 35 mm rebar cover) establish the absolute baselines. The four conditions produce systematically distinct joint signatures: Model A exhibits uniform high resistivity with clean rebar hyperbolae and no anomalous reflections; Model B produces a localised ERT low-ρ anomaly (ρ_min = 1.46 Ω·m) co-located with a negative-polarity (R = −0.68) GPR crack-mouth reflection confirming water-fill; Model C produces pervasive low-ρ with a smooth depth gradient and 50–65% GPR amplitude attenuation (−6.0 to −9.1 dB); Model D produces the same bulk GPR signatures as Model C but with a critically different ERT spatial texture—a heterogeneous near-surface layer above a sharp boundary at z ≈ 40 mm with depth-preferential low-ρ concentrated at rebar level. This depth-preferential signature, quantified here by a reproducible Depth-Preferential Index (DPI), is the primary ERT-only diagnostic criterion distinguishing active corrosion from pervasive saturation. For the Model C versus Model D distinction, the GPR response is non-discriminating; this high-risk distinction is resolved exclusively by the ERT depth-preferential criterion. The calibration demonstrates that GPR and ERT are physically non-redundant in the strict sense: neither method alone can unambiguously discriminate all four states, but their combination yields correct classification within the controlled laboratory conditions and subject to the stated qualification conditions. The corrosion state was confirmed at the regime level (chloride above the depassivation threshold, under accelerated polarisation) but was not quantified electrochemically, so the depth-preferential signature is interpreted as an indirect spatial proxy for active corrosion rather than a measurement of corrosion rate. Seven failure modes are quantitatively characterised and embedded in the framework as a priori qualification conditions. The calibrated reference values (ρ₀, A₀, Stage 2 thresholds, depth-preferential criterion) are specific to the laboratory mix and curing history and require local Stage 1 recalibration for field application. Full article

We report on the finite temperature staggered spin susceptibility $\chi \left(Q\right)$ as a function of the mode–mode coupling constant $y_1$ in the self-consistent renormalization theory of two-dimensional antiferromagnetic spin fluctuations with zero-point quantum fluctuations just at the quantum critical point ($y_0$ = 0). We find that the value $y_1$ = 0.1 is a criterion to classify the effect of the zero-point spin fluctuations on the temperature dependence of $\chi \left(Q\right)$ into a Curie law for weak $y_1<$ 0.1 and a Curie–Weiss type or a power law type for strong $y_1>$ 0.1. The absence of a Curie–Weiss temperature can serve as an identifying criterion for QCP ($y_0$ = 0) in systems with weak mode–mode coupling ($y_1<$ 0.1). Experimental application on the $y_1$ classification is shown to several itinerant layered antiferromagnetic systems through an analysis of nuclear spin–lattice relaxation rates. Full article

Filters serve as critical facilities for ensuring the seepage stability of earth-rock dams and tailings dams; their failure poses severe threats to dam safety. Traditional filter design criteria are constrained by the diversity of soil types and fail to account for the influence of pore characteristics (e.g., constriction size) on the soil retention and hydraulic conductivity of filters. Design methods recommended in design codes only provide gradation envelope boundaries without specifying exact gradation curves. This paper proposes a filter design approach based on the natural clogging concept. Using Terzaghi’s interlayer coefficient as the initial parameter, this method induces stable clogging layers of base soil within the filter through sediment-laden seepage, adopting the post-clogging gradation as the design gradation. Experimental results demonstrate that: (1) when the initial interlayer coefficient α of the filter is ≤10.4, the base soil retention rate exceeds 97% (soil loss < 3%), surpassing the conservative limit of α < 4 in Terzaghi’s criterion; (2) the final interlayer coefficient α of filters ZS-2 to ZS-5 ranges between 1.15 and 2.48, with i_b/i_f values between 6.26 and 23.68, simultaneously satisfying Terzaghi’s requirements for soil retention and hydraulic conductivity; (3) this method explicitly defines the specific gradation curve of the filter, with the final gradation curve of ZS-5 largely falling within the envelope recommended by design codes. The proposed method integrates Terzaghi’s interlayer coefficient criterion with the influence of pore characteristics on filter performance, offering a new design strategy for tailings dam filters with fine-grained base soils, preliminarily validated under laboratory conditions. Full article

Unbonded flexible pipes are key components of deepwater high-temperature oil and gas transportation systems, and their bending performance directly affects in-place response and fatigue assessment. Interlayer contact and sliding of tensile armor layers govern bending hysteresis; under high-temperature service, incompatible thermal expansion of metallic and polymer layers changes contact pressure and the associated slip conditions. This study develops a thermo-mechanical bending hysteresis model in which thermally induced interlayer contact pressure links the radial temperature field to the bending response. A steady-state multilayer-cylinder heat-transfer model and a thermoelastic compatibility formulation are used to determine temperature distributions and interlayer contact pressures. The contact-pressure variation is then introduced into the tensile-armor slip criterion and the incremental moment-curvature relationship, covering non-slip, partial-slip, and full-slip stages. A sequentially coupled finite element model of a 2.5-inch unbonded flexible pipe is established for validation. The numerical model predicts hysteresis loop area and unloading/reverse-loading stiffness with relative deviations of 6.02% and 5.09% from the finite element results, respectively. Increasing internal temperature increases contact pressure and critical slip curvature, prolongs partial slip, and substantially increases hysteretic energy dissipation. The model provides a basis for high-temperature bending stiffness determination and fatigue-oriented analysis of unbonded flexible pipes. Full article

This study focuses on a 155 mm 32CrNi3MoV steel barrel and presents a thermochemically coupled phase transformation and diffusion dynamics model. The model leverages the significant disparity between radial and axial temperature gradients to simplify the heat conduction problem to a one-dimensional transient formulation. The temperature field distribution during firing sequences is solved analytically, accounting for the dynamic shift in critical phase transformation temperatures under high heating rates. The evolution of the martensitic layer thickness under repeated thermal shock is subsequently calculated. A numerical model for the pulsed diffusion of C and N is established based on Fick’s second law, incorporating the competitive diffusion–phase transformation mechanisms that govern martensite/austenite interface migration. To quantitatively evaluate the synergistic contribution of C and N to austenite stabilization, a carbon equivalent (Ceq) model is introduced, with the weight coefficient of N relative to C determined to be 0.68 and the critical Ceq required to lower the martensite start temperature below 25 °C calculated as 1.15 wt%. Concurrently, the microstructure and elemental distribution within the austenite layer of the retired barrel are systematically characterized using multi-scale techniques. The results indicate that the austenite layer on the inner bore surface arises from the synergistic effects of cyclic thermal-shock-induced phase transformation and elemental diffusion. Based on the Ceq criterion, the austenite layer thickness increases rapidly during the initial ~100 firing cycles, after which the growth rate slows significantly: it reaches approximately 1.27 μm after the first cycle and 2.94 μm after 1000 cycles, with only 0.2 μm of additional thickening between 100 and 1000 cycles—consistent with the experimentally observed range of 1.52–4.16 μm. The martensitic layer formed during the first firing cycle exhibits low thermal conductivity, which impedes subsequent heat transfer and leads to stabilization of its thickness at a characteristic depth. Grain refinement induced by repeated thermal shock provide short-circuit diffusion paths for elemental diffusion, accelerating compositional homogenization within the austenite layer and resulting in a stepped concentration profile at the interface. This study provides a representative example of non-equilibrium coupled phase transformation–diffusion phenomena under extreme transient loading. The established thickness prediction model can provide guidance for service life assessment of large-caliber barrels, offering both theoretical foundations and practical engineering guidance for their material design and performance optimization. Full article

In the present study, the influence of microstructural morphology and dendritic refinement on the electrochemical corrosion behavior of directionally solidified aluminum-based structures (columnar and equiaxed) with Si contents between 6 and 12.6 wt. % was investigated in a 0.5% NaCl solution at room temperature. Corrosion resistance was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The directional solidification process was repeated for each of the alloy compositions at different cooling rates, yielding different secondary dendritic spacing values. The columnar-to-equiaxed transition (CET) was observed to occur when the temperature gradient in the melt decreased to values between −1.85 and 0.75 °C/cm. In addition, a small increase in the microhardness values was observed as a function of the Si content. The same applies to tensile strength values. The values of the polarization resistance are used as a basic criterion for the evaluation of the corrosion resistance of alloys. The columnar grain zone presents higher corrosion resistance than the equiaxed grain zone, despite presenting coarser dendritic spacing. This behavior contrasts with the commonly expected improvement in corrosion resistance associated with microstructural refinement and indicates that passive-layer stability and cathodic phase distribution play a dominant role in the electrochemical behavior. When the polarization resistance decreases with the increase in the distance from the base, the grain size and secondary dendritic arm spacings increase. In addition, when the polarization resistance increases, the critical temperature gradient decreases. This work allows us to conclude that the modification of thermal parameters in the solidification process can be used for the development of an optimized microstructure morphology and to optimize corrosion resistance in Al–Si alloys through control of dendritic spacing and passive film formation mechanisms. Full article