Search Results (2,990)

Rolling bearings in modern wind turbines operate under demanding tribological conditions that include high contact stresses, mixed lubrication, transient loads, electrical discharge, corrosion, and hydrogen-assisted damage. These factors contribute to premature failures such as micropitting, scuffing, white etching cracks (WECs), and electrical fluting, which remain major reliability challenges in both onshore and offshore turbines. Surface-engineering technologies have emerged as effective tools to mitigate these failure modes. Carbon-based coatings improve sliding performance and reduce wear under boundary-lubricated conditions; black oxide conversion layers enhance the corrosion resistance, lubricant retention, and early-life running-in behavior; and insulating ceramic coatings protect generator bearings from electrical discharge damage. Additional solutions, including polymer overlays, composite films, and hybrid ceramic architectures, offer further improvements in friction, surface fatigue resistance, and environmental robustness. This manuscript reviews the current state of coated bearing technologies relevant to wind turbine applications, synthesizing findings from tribological research, industrial practice, and emerging material developments. While only a limited number of coating suppliers provide documented evidence of coating use in wind turbine drivetrain bearings, the collective progress in surface engineering demonstrates clear potential for improving reliability and extending service life across the installed turbine base. The analysis highlights the mechanisms by which coatings enhance performance, the conditions under which they are most effective, and the gaps that remain in field validation and large-scale deployment. Coated bearings represent a promising pathway toward higher turbine availability, reduced maintenance costs, and improved drivetrain durability. Continued advances in carbon-based films, multilayer architectures, and insulating coatings, combined with better integration of lubrication strategies and condition-monitoring technologies, will play an increasingly important role in enabling the next generation of high-power wind energy systems. Full article

Although large-scale wind and solar power provide green electricity, their intermittency and reverse-peak characteristics pose severe challenges to the secure operation of power systems. Pumped storage hydropower (PSH), as the most mature and economically attractive large-scale energy storage technology, enables temporal energy shifting and serves as a core flexible resource for smoothing renewable fluctuations and peak load shaving. In a new power system dominated by renewables, the reverse distribution between resources and loads gives rise to a typical “three-zone coexistence” pattern, i.e., renewable-rich zones, load centers, and hub zones coexist. However, existing research lacks in-depth modeling of zonal functional differences and fails to reveal the coupling mechanism between inter-zonal section constraints and the temporal energy behavior of pumped storage plants (PSPs). To address these gaps, this paper proposes a zonal-differentiated optimal dispatch model for multiple PSPs considering inter-zonal section constraints. The model establishes a “zonal role–PSP behavior” matching mechanism, assigning differentiated objectives and operational constraints to PSPs located in different zones, and thereby automatically generating charging/discharging strategies that match each zone’s functional positioning. It integrates section power flow constraints with the energy balance equations of PSPs in each zone into a unified framework, quantifying how section congestion restricts the “cross-zone energy shifting” efficiency of PSPs. Furthermore, a congestion-driven adaptive rule is derived from the above coupling framework. Case studies on a three-zone test system demonstrate that the proposed model effectively reduces wind and solar curtailment, alleviates section overloading, and lowers total operating costs, while the adaptive rule provides real-time decision support for dispatchers. The proposed model is applicable to power grids at various levels exhibiting the “three-zone coexistence” characteristic, offering theoretical support and a practical tool for the joint dispatch of multiple PSPs under high-penetration renewable energy integration. Full article

Heating, ventilation and air conditioning (HVAC) accounts for an overwhelmingly large proportion of building energy consumption. Mass low-grade cold and heat energy dissipates during system operation, endowing pulsating heat pipes (PHPs) with promising application prospects in building energy systems. Combining experimental tests and the phase-space reconstruction method, this paper investigates the intrinsic correlation between the flow behavior of working fluids and chaotic characteristics under varied working fluids, heating powers and liquid filling ratios. The working fluid type dominates the oscillation characteristics of pulsating heat pipes. When distilled water serves as the working fluid, the attractor presents a scattered distribution. In contrast, the PHP charged with HFE-7100 achieves stable unidirectional circulation with high-frequency, small-amplitude pulsation, forming a densely distributed attractor. Increasing the flow velocity of the working fluid drives the attractor distribution to evolve from scattered to concentrated. Intermittent flow of the working fluid induces a multi-temperature-zone distribution on the tube wall, and the attractor takes on a multi-region spiral morphology. A low liquid filling ratio triggers working fluid dry-out, and the attractor trajectory maintains a continuous unidirectional upward trend; by comparison, the attractor shows a multi-region spiral distribution under high filling ratio conditions. Research on chaotic dynamic characteristic identification, evolutionary law analysis and stable domain regulation of pulsating heat pipes can lay a theoretical foundation for structural optimization and operating condition adjustment of high-performance pulsating heat pipe devices for building waste heat recovery. Full article

As sports content platforms increasingly occupy a central role in consumers’ media consumption and fitness-related activities, understanding the factors that encourage sustained user engagement has become an important research concern. Although corporate social responsibility (CSR) has been widely recognized as a strategic tool for enhancing consumer perceptions and organizational reputation, prior research has focused primarily on traditional sports organizations and general commercial settings, with limited attention given to its influence within digitally mediated sports content platform environments. Therefore, this study investigates the relationships among CSR, empathy, attitude, and usage intention in the context of sports content platforms. Data were collected in Republic of Korea from 225 university students who regularly use sports content platforms. Structural equation modeling was employed to test the proposed conceptual framework. The findings reveal that CSR positively influences empathy and attitude, while empathy positively influences attitude. In addition, attitude is positively associated with usage intention. However, CSR does not directly influence usage intention, and empathy does not exhibit a direct relationship with usage intention. These results suggest that users’ continued engagement with sports content platforms is shaped more by evaluative attitudes than by direct emotional responses or perceptions of social responsibility alone. The study contributes to the literature by extending CSR research beyond traditional sports organizations into digitally transformed sports content platform environments and by identifying the psychological mechanisms through which CSR shapes user behavior in digital sports media environments. It also offers practical guidance for platform operators seeking to strengthen long-term user relationships through socially responsible initiatives. Full article

This study examines the linguistic construction and cultural framing of tricksterhood in Dagaare folktales through an analysis of five narratives centered on the character of Badɛre (Spider). Drawing on discourse analysis and ethnopragmatics, the study investigates three main research questions: (i) how Badɛre is linguistically and semantically constructed in the narratives; (ii) what cultural meanings and values are embedded in his behavior; and (iii) how tricksterhood functions within Dagaare society. Data were collected through fieldwork conducted in February 2025 in the Dagaaba communities of Sombo and Guree in the Upper West Region of Ghana. The study employed qualitative methods, including semi-structured interviews, focus group discussions, and storytelling sessions, all of which were audio-visually recorded. The findings show that Badɛre is lexically constructed as clever, cunning, deceptive, greedy, opportunistic, and sometimes foolish, while semantically functioning as a figure of irony, reversal, social critique, and moral ambiguity. The analysis further reveals that tricksterhood in Dagaare folklore operates through four interconnected dimensions: moral agency, wisdom and intelligence, social critique, and ambivalence. Overall, the study demonstrates that Dagaare trickster narratives are not merely entertaining stories, but culturally embedded forms of moral instruction, social commentary, and indigenous knowledge transmission. Full article

Artificial intelligence (AI) is increasingly used in water research. However, many AI models, particularly complex machine learning models, often generate outcomes that are difficult for humans to interpret. Explainable artificial intelligence (XAI) has been developed to address these challenges by providing transparent and human-interpretable explanations of model behavior and predictions. We conducted a structured narrative review using predefined searches of Web of Science Core Collection and Scopus to synthesize empirical XAI applications across six water-research domains: hydrological processes, water quality and pollution, groundwater systems, urban water systems, climate–water interactions, and water and wastewater treatment. The review covers feature-importance methods, SHapley Additive exPlanations (SHAP), Local Interpretable Model-agnostic Explanations (LIME), partial dependence plots (PDPs), individual conditional expectation (ICE) plots, accumulated local effects (ALE) plots, counterfactual explanations, and deep-learning attribution methods. Building on previous reviews and perspectives focused on particular water domains or methodological priorities, we provide a cross-domain synthesis of XAI spanning natural and engineered water systems, with emphasis on method selection, model and data compatibility, explanation reliability, and operational implementation. These capabilities, however, must be interpreted with appropriate caution because XAI explanations remain conditional on the data, fitted model, and explanation method, and therefore should not be treated as evidence of causal mechanisms or environmental controls. Recognizing these limitations, we provide practical guidance for selecting and evaluating XAI methods and outline priorities for developing reliable, scalable, and operationally useful AI systems for water research and management. Full article

The increase in the number and complexity of interconnected systems requires new methods to identify potential threats in today’s hyperconnected world. This trend affects systems ranging from smart homes and Internet of Things (IoT) devices to critical infrastructure which must be equipped with the corresponding cyber defense methods. Given the new landscape, it is more difficult for classical cybersecurity systems to stay up to date with novel threats, as well as to keep track of all interconnected devices defined by various protocols and behaviors. Artificial intelligence (AI) represents a strong candidate to complement traditional cyber defense methods due to its adaptability to variation and capability to identify complex data patterns, which has led researchers to develop state-of-the-art anomaly detection systems. The current critical review aims to analyze the scientific literature on three dimensions including used algorithms and datasets, domain challenges hindering AI deployment in productive environments, and the capability of explainable artificial intelligence (XAI) to support cyber security experts with insights into the model’s inner workings and decision rationale. Compared to existing scientific reviews, this paper moves beyond algorithmic comparison by providing a methodological interpretation of AI anomaly detection landscape, demonstrating how data availability, learning paradigms, and explainability collectively influence the evolution of cyber defense research towards operational deployment. This approach revealed that AI development for cyber defense is highly heterogenous, and that the available datasets strongly influence the algorithm of choice, rather than the models being chosen methodologically based on proven performance. The analysis further indicates that operational deployment remains challenging, as the literature continues to report substantial limitations related to data quality, computational requirements, and model interpretability. Full article

As a critical regulating component in subsea Christmas tree systems, the cage-type choke valve governs the overall production efficiency and operational reliability of offshore oil and gas exploitation owing to its unique internal flow field characteristics. In accordance with the in situ operating conditions of the target oilfield, this paper performs a numerical simulation and systematic analysis on the flow field behaviors of a cage-type choke valve. Based on the fundamental theories of computational fluid dynamics (CFD), a three-dimensional coupled flow and heat transfer numerical model for the target choke valve is constructed via the FLUENT solver. Flow parameters under diverse pressure difference conditions are measured, validating the accuracy and feasibility of the established numerical model. Corresponding model hypothesis criteria and boundary condition configuration schemes are explicitly defined. Spatial distribution characteristics of the internal temperature, velocity, and pressure fields of the choke valve under different operating conditions are obtained through numerical simulation. Ten monitoring nodes uniformly arranged along the fluid domain from the inlet to the outlet are selected for quantitative analysis. The research results clarify that lower seawater temperature intensifies heat dissipation, leading to the observed temperature decrement, and confirm that the cage orifice structure dominates the flow acceleration, with the pressure drop magnitude linearly correlating with the inlet–outlet differential pressure. The research methodology and numerical findings of this study can provide a reliable basis for structural optimization and operating condition matching of cage-type choke valves applied in subsea oil and gas production systems. Full article

This work is a theoretical study aimed to address the lubrication failure of Tom-Pac TP-2557 gel lubricant on the textured high-entropy alloy coatings (THEACs) under wide-temperature-range operating conditions; the rheological lubrication properties of the surface are investigated in this work. Based on lubrication theory and non-Newtonian fluid mechanics, a gel lubrication viscosity model considering temperature dependence and a thermo-mechanical coupled constitutive relationship for the THEACs are established. The results show a significant shear-thinning behavior of the gel within a moderate low-to-medium temperature range, and the onset temperature of thermal degradation is identified. Optimal geometrical and distributional parameters of the surface textures, along with a favorable surface energy range, are determined to achieve desirable interfacial shear strength. Moreover, an anchoring-slip synergistic mode arising from surface energy heterogeneity is found to further enhance lubricating film stability. This research provides a theoretical basis for the gel lubrication design of the THEACs. Full article

This paper presents a numerical investigation of the effect of rotational speed on the development of leakage flow in a low-speed axial fan equipped with a rotating shroud. Rotor deformation induced by centrifugal forces and aerodynamic loading is taken into account through a one-way coupling between steady CFD simulations and static FEM analyses. Aerodynamic and structural results obtained at four rotational speeds are validated against available experimental data collected by the same research group, and the different leakage flow patterns associated with rotor deformation are correctly reproduced. Subsequently, the deformed geometries corresponding to two rotational speeds and operating at the same non-dimensional flow coefficient are used to perform URANS simulations. The numerical results provide insight into the leakage flow behavior within the gap between the rotating shroud and the stationary casing, a region that cannot be experimentally investigated due to optical access limitations. It is shown that the leakage flow rate through the gap shows limited sensitivity to rotor deformation, as it scales with rotational speed, and it is fed by two main contributions: a flow directly extracted from the rotor outlet and a recirculating flow developing along the mounting panel. Conversely, the non-dimensional angular momentum flow rate is larger at the lower rotational speed, corresponding to the case in which the leakage flow is rapidly re-ingested by the rotor. This indicates that the centrifugal effects associated with the leakage flow swirl are not responsible for the observed change in leakage flow pattern. Finally, significant periodic and non-periodic components are identified within the leakage flow. These components are expected to contribute to the formation of the large-scale structures impinging on the rotor blades and thus generating significant noise. Full article

As health services shift to digital delivery, older adults face practical online risks, including operational errors, difficulty interpreting clinical information, unclear privacy consent procedures, and telecommunications fraud. Existing empirical work mostly adopts questionnaire and interview designs to document older adults’ real-world digital usage, yet few studies systematically analyze policy documents as an external intervention system and assess how they address four core usage barriers: limited digital proficiency, constrained service access, weak sustained participation, and individualized online safety threats. This paper analyzes 1008 policy records extracted from the Peking University Legal Database covering 2007–2025, and develops a four-dimensional analytical framework split into B1 (Digital Capacity and Age-Friendly Support), B2 (Digital Health Management Support), B3 (Home- and Community-Based Care Support), and B4 (Institutional Care and Risk Governance). The analytical toolkit combines a Capability–Opportunity–Motivation–Behavior (COM-B) diagnostic model, an M1–M4 intervention-mechanism coding protocol, Latent Dirichlet Allocation (LDA) topic modeling, and two indices: the Digital Adaptation Policy Orientation Index (DAPOI) and the Behavioral Intervention Diversity Index (BIDI). Coding outputs reveal a pronounced structural imbalance in policy allocation for older adults’ digital health in China: community and institutional governance clauses (B3, B4) dominate the corpus, while person-centred support including one-on-one operational coaching, clinical data interpretation guidance and offline manual backup channels accounts for a marginal share of all coded entries (B1, B2). Age-friendly digital policies issued circa 2020 serve primarily short-term emergency adjustments instead of permanent institutional arrangements. Built on full-text policy coding outputs, this work defines policy-supported digital resilience as a holistic protective system formed by coordinated institutional clauses. Every result reported is sourced exclusively from supply-side policy records, which provides policy-level evidence for subsequent behavioral research on older adults’ digital risk management and digital welfare construction. Full article

Addressing the opportunistic behavior of retailers operating within the unique spaces of transportation hub ecosystems, which exploit strong temporal and spatial constraints and geographic monopolies, this paper constructs a three-party evolutionary game model involving transportation hub authorities, micro-merchant enterprises, and transient consumers. Using China’s high-speed rail hubs as the research context, this study develops a theoretical evolutionary game model with numerical simulations and endogenously embeds the backlash from informal digital public opinion into the regulatory decision-making framework. The study thoroughly deconstructs the mechanisms of behavioral evolution and control pathways within highly constrained micro-spaces. The study reveals that: (1) Static, constant regulation, lacking negative feedback linked to the system’s state, inevitably causes the system to fall into a non-convergent “regulation-speculation” cyclical oscillation; (2) A state-dependent dynamic regulatory mechanism can effectively serve as an adaptive damper to quell strategic oscillations; however, because it fails to eliminate speculative premiums, the system becomes locked in a mediocrity trap characterized by low compliance rates; (3) Endogenous digital public opinion leverage can reconfigure the phase space structure and trigger topological bifurcations in the system, breaking the attractor region of the mediocrity equilibrium and driving the game system to undergo a structural transition, with asymptotic convergence to the pure-strategy ideal point. Furthermore, digital empowerment drives consumers to exhibit an inverted U-shaped transient behavioral trajectory of “forced silence—awakening to rights advocacy—rational self-governance,” thereby scientifically deconstructing the public’s dual silence paradox in the digital age. This study not only provides a mathematical basis for the public sector to achieve a paradigm shift from rigid regulation to flexible adaptive governance and structural safe retreat at the micro level, but also offers strategic insights for intertemporal compliance management by micro-merchants. Full article

Weathering steels have been widely used in transportation, energy facilities, and civil infrastructure because of their good atmospheric corrosion resistance and long service life. Their corrosion resistance is generally achieved by adding alloying elements such as Cu, P, Cr, and Ni, which promote the formation of a stable and protective rust layer. Among these elements, however, Ni and Cr are relatively expensive and their resources are limited. Therefore, reducing the use of Ni and Cr while maintaining good corrosion resistance has become an important issue in the development of weathering steels. Recent studies have demonstrated that rare-earth elements can markedly improve the corrosion resistance of steels through multiple mechanisms, including optimization of rust-layer structure, microstructural refinement, inclusion modification, and regulation of grain-boundary characteristics. Rare-earth microalloying therefore provides an effective approach to reducing the consumption of conventional alloying elements in weathering steels. This paper systematically reviews the corrosion mechanisms of weathering steels, the evolution of rust-layer structures, and the roles of alloying elements, with particular emphasis on the effects of Cu, P, Cr, and Ni on the densification and stabilization of rust layers. The microalloying effects of rare-earth elements, their inclusion-modification behavior, and their deoxidation and desulfurization mechanisms are also summarized, and their roles in reducing pitting susceptibility and promoting the formation of stable protective rust layers are clarified. In addition, the occurrence states of rare-earth elements in steel and their effects on performance stability are discussed. Key challenges encountered in the industrial application of rare-earth steels, including fluctuations in rare-earth yield and continuous-casting nozzle clogging, are also summarized. The available evidence indicates that the effective application of rare-earth elements in weathering steels remains constrained by molten-steel cleanliness, inclusion control, and the stability of continuous-casting operations. Future research should focus on technologies for the stable addition and controlled occurrence of rare-earth elements under low-oxygen and low-sulfur smelting conditions, thereby enabling the efficient utilization and stable industrial application of abundant rare-earth resources in weathering steels. Full article

Commercial carbon-based electrodes such as graphite felt and carbon felt in all-vanadium redox flow batteries suffer from inherent drawbacks, including slow vanadium ion redox kinetics, insufficient intrinsic catalytic activity, fiber corrosion, and functional group loss under strong acidic oxidative conditions, significantly limiting battery energy efficiency and long-term operational reliability. Rare-earth elements, with their unique 4f electron shell structure, tunable electronic levels, abundant surface oxygen vacancy defects, and strong coordination ability, offer a dual pathway—electronic and microstructural modulation—to optimize the interfacial electrocatalytic behavior of carbon electrodes, providing a novel materials system to overcome electrode performance bottlenecks in vanadium batteries. This review systematically summarizes recent advances in rare-earth-functionalized carbon electrodes and electrocatalysts for vanadium redox flow batteries, elaborating on core modification strategies, performance enhancement trends, and synergistic catalytic mechanisms. It also presents quantitative experimental results from the literature to clearly demonstrate the benefits: CeO₂-modified graphite felt at 0.2 wt% shows a 10.8% increase in energy efficiency compared to pristine graphite felt at a current density of 200 mA·cm⁻², while multi-rare-earth co-doped carbon electrodes achieve a 65% reduction in charge transfer resistance relative to unmodified electrodes. The review systematically categorizes two dominant modification routes—surface nano-decoration with rare-earth oxides and lattice bulk doping with rare-earth elements—and summarizes design principles and enhancement mechanisms of diverse composite catalytic systems, including rare-earth–carbon nanocomposites, rare-earth-based heterojunctions, and porous rare-earth catalysts. It further analyzes critical challenges in current research, such as unclear long-term stability mechanisms, high costs of high-purity rare-earth raw materials, immature large-scale fabrication processes, and limited in situ dynamic characterization techniques. Compared with existing reviews, this work clearly distinguishes between surface loading and lattice doping as two distinct rare-earth modification approaches, clarifying their differences in active site formation, electronic regulation logic, and cycling stability. It establishes a comprehensive theoretical framework for the coupled electronic–geometric effects in rare-earth-modified carbon electrodes, linking the intrinsic physicochemical properties of rare earths, material microstructure design, and battery electrochemical performance. Moreover, it innovatively proposes a pathway toward full-lifecycle recycling and reuse of rare-earth-based catalytic electrodes for industrial implementation. This review provides a complete theoretical foundation for developing high-performance, long-cycle, low-cost vanadium redox flow battery electrode materials and supports their engineering scale-up, contributing to the development of large-scale, long-duration energy storage technologies. Full article

House rules are a central governance mechanism in peer-to-peer accommodation, yet prior research reports mixed effects on guests’ booking behaviors. We propose that these inconsistencies arise from overlooking the intertemporal spillover of rules, the extent to which the consequences of violation extend beyond the focal stay. Drawing on construal level theory, we distinguish between High-Spillover Rules, which protect long-term property quality and future guest experience, and Low-Spillover Rules, which regulate encounter-bounded behaviors and operational procedures. Using natural language processing and hierarchical regression, we analyzed 883 P2P accommodation listings from a Chinese context. The results show that High-Spillover Rules increase booking volume, whereas Low-Spillover Rules decrease it only when host identity-relevant expressions are absent. The second experiment, with 138 samples, provides causal evidence that these effects are mediated by perceived quality and perceived threats to freedom, respectively. A third experiment, with 183 samples, further demonstrates that host identity-relevant expressions attenuate both effects by weakening the quality-signaling advantage of High-Spillover Rules and reducing autonomy-related resistance to Low-Spillover Rules. This research advances understanding of governance disclosures in P2P markets and offers actionable guidance for rule design and platform communication strategies. Full article