Search Results (301)

To meet safety regulations in underground coal mines, wireless power transfer (WPT) systems must house both the transmitter and receiver within explosion-proof enclosures. However, eddy currents induced on the surfaces of these non-ferromagnetic metal enclosures significantly hinder magnetic flux coupling, thereby reducing transmission efficiency. This paper proposes a slotting technique applied to explosion-proof enclosures to suppress eddy currents, along with the integration of magnetic flux focusing materials into the coils to enhance coupling. Simulations were conducted to compare three system configurations: (i) a WPT system without enclosures, (ii) a system with solid (unslotted) enclosures, and (iii) a system with slotted enclosures. The results show that solid enclosures reduce efficiency to nearly zero, whereas slotted enclosures restore efficiency to 90% of the baseline system without enclosures. Joule heating remains low in the slotted explosion-proof enclosures, with energy losses of 2.552 J for the transmitter enclosure and 2.578 J for the receiver enclosure. A conservative first-order estimation confirms that the corresponding temperature rise in the enclosure surfaces remains below 50 °C, which is well within the 150 °C limit stipulated by the Chinese National Standard GB 3836.1-2021 (Explosive Atmospheres—Part 1: Equipment General Requirements). These findings confirm effective eddy current suppression and efficiency recovery without compromising explosion-proof safety. The core innovation of this work lies not merely in the physical slotting approach, but in the development of a precise equivalent circuit model that fully incorporates all mutual inductance components representing eddy current effects in non-ferromagnetic explosion-proof enclosures, and its integration into the overall MCR-WPT system circuit. Full article

Water is the source of life and also the lifeline of cities. The reconstruction of secondary water supply systems is a key component of urban renewal reforms, and the collaborative governance of such projects has become a focal topic through academic research. In this article, we try to discover the path to successful “bottom-up” collaborative water governance with Collins’s theory of interaction ritual chains (IRC) through a case study of a secondary water supply reconstruction program in J Estate, Jinshan District, Shanghai. The case study involved a total of 104 households, and we employed convenience sampling for all households through door-to-door inquiries, which included semi-structured interviews and non-participant observations. A total of 15 households participated in our interview. This study demonstrates that repeated social interactive rituals, such as bodily co-presence, rhythmic synchronization, and shared signs, can stimulate the accumulation of residents’ emotional energy, which becomes the initial power to promote community water governance and, in return, becomes the driving force for sustained collective action and mutual trust. Drawing on Collins’s theory of IRC, this article fills a gap by explaining the symbolic mechanism driven by emotions and personal relationships that macro-level governance ignores. We also demonstrate the spillover effects of such social rituals and propose policy recommendations that governments should apply, using these rituals to mobilize and consolidate residents’ emotions to create a virtuous circle of collaborative governance. Full article

For power electronic transformer (PET) based Modular Multilevel DC-Link Based T-type Converters (MMDTC) with Double Active Bridges (DABs) (namely DABs-based MMDTC-PET), the sub-module capacitor voltages exhibit relatively large ripples. To reduce the voltage ripple of sub-module capacitors, this paper proposes a novel MMDTC-PET structure that utilizes the Three-Port Active Bridges (TABs) to replace the DABs as the isolation stage (TABs-based MMDTC-PET). When the two full bridges of the TAB on the primary side adopt identical phase-shift modulation, the two sub-module capacitors within the upper and lower arms form a parallel connection. This configuration endows the sub-module capacitors with switched-capacitor characteristics, suppressing voltage ripple in the sub-module capacitors and enabling power ripple flow to the secondary side. Meanwhile, by leveraging the characteristic that the AC power components of the upper and lower arm sub-modules have equal amplitudes but opposite phases, these AC power components are mutually canceled on the secondary side of the TAB. Simulation and experimental results verify the effectiveness of the proposed scheme. Full article

Driven by the growing demand for sustainable resource utilization, the recovery of valuable constituents from spent lithium-ion batteries (LIBs) has attracted considerable attention, whereas conventional recycling processes remain energy-intensive, inefficient, and environmentally detrimental. Herein, an efficient and environmentally benign separation strategy integrating dielectrophoresis (DEP) and magnetophoresis (MAP) is proposed for isolating the primary components of “black mass” from spent LIBs, i.e., lithium iron phosphate (LFP) and graphite microparticles. A coupled electric–magnetic–fluid dynamic model is established to predict particle motion behavior, and a custom-designed microparticle separator is developed for continuous LFP–graphite separation. Numerical simulations are performed to analyze microparticle trajectories under mutual effects of DEP and MAP and to evaluate the feasibility of binary separation. Structural optimization revealed that the optimal separator configuration comprised an electrode spacing of 2 mm and a ferromagnetic body length of 5 mm with 3 mm spacing. Additionally, a numerical study also found that an auxiliary flow velocity ratio of 3 resulted in the best particle focusing effect. Furthermore, the effects of key operational parameters, including electric and magnetic field strengths and flow velocity, on particle migration were systematically investigated. The findings revealed that these factors significantly enhanced the lateral migration disparity between LFP and graphite within the separation channel, thereby enabling complete separation of LFP particles with high purity and recovery under optimized conditions. Overall, this study provides a theoretical foundation for the development of high-performance and environmentally sustainable LIBs recovery technologies. Full article

To address the challenge of effectively filtering out noise components in GPS coordinate time series, we propose a denoising method based on parameter-optimized variational mode decomposition (VMD). The method combines permutation entropy with mutual information as the fitness function and uses the crayfish (COA) algorithm to adaptively obtain the optimal parameter combination of the number of modal decompositions and quadratic penalty factors for VMD, and then, sample entropy is used to identify effective mode components (IMF), which are reconstructed into denoised signals to achieve effective separation of signal and noise The experiments were conducted using simulated signals and 52 GPS station data from CMONOC to compare and analyze the COA–VMPE–WD method with wavelet denoising (WD), empirical mode decomposition (EMD), ensemble empirical mode decomposition (EEMD), and complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) methods. The result shows that the COA–VMPE–WD method can effectively remove noise from GNSS coordinate time series and preserve the original features of the signal, with the most significant effect on the U component. The COA–VMPE–WD method reduced station velocity by an average of 50.00%, 59.09%, 18.18%, and 64.00% compared to the WD, EMD, EEMD, and CEEMDAN methods. The noise reduction effect is higher than the other four methods, providing reliable data for subsequent analysis and processing. Full article

Against the backdrop of the continuous growth in global demand for mineral resources, efficient and accurate mineral exploration technologies are of paramount importance. Therefore, utilizing remote sensing technology, which features wide coverage, a non-contact nature, and multi-source data acquisition, is of great significance for conducting mineral resource exploration and prospecting research. This study focuses on the Tsagaankhairkhan copper–gold mining area in Mongolia and proposes a structural-alteration anomalies coupling mining prediction method based on the collaboration of multi-source remote sensing data. By comprehensively utilizing multi-source image data from Landsat-8, GF-2, and Sentinel-2, and employing methods such as principal component analysis (PCA), band ratio, and texture analysis, we effectively extracted structural information closely related to mineralization, as well as alteration anomaly information, including hydroxyl alteration anomalies and iron-staining alteration anomalies. Landsat-8 and Sentinel-2 data were employed to extract and mutually validate hydroxyl and iron-staining alteration anomaly information in the study area, thereby delineating alteration anomaly zones. By integrating the results of structural interpretation, the distribution of alteration anomaly information, and their spatial coupling characteristics, we explored the spatial coupling relationship between structural and alteration anomalies, analyzed their mineral control patterns, and identified 7 prospecting target areas. These target areas exhibit abundant mineral anomalies and favorable structural settings, indicating high metallogenic potential. The research findings provide crucial clues for the exploration of the Tsagaankhairkhan copper–gold mine in Mongolia and can guide future mineral exploration and development efforts. Full article

As a key component for maintaining the efficient and stable operation of flexible DC transmission systems, the arm reactor often suffers from uneven loss distribution and localized overheating in its windings due to the superimposed AC and DC currents, which adversely affects its operational lifespan. Furthermore, arm reactors are frequently deployed in offshore environments for long-distance, high-capacity power transmission, imposing additional requirements on energy utilization efficiency and seismic resistance. To address these challenges, this study proposes an optimization design method for arm reactors based on a triple-constraint mechanism of “equal resistive voltage–equal loss density–equal encapsulation temperature rise,” aiming to achieve “low loss–low temperature rise–low weight.” First, an equivalent electromagnetic model of the arm reactor under combined AC and DC operating conditions is established to analytically calculate the self- and mutual-inductance-distribution characteristics between winding layers and the loss distribution across windings. The calculated losses are then applied as heat sources in a fluid–thermal coupling method to compute the temperature field of the arm reactor. Next, leveraging a Kriging surrogate model to capture the relationship between the winding temperature rise in the bridge-arm reactor and the loss density, encapsulation width, encapsulation height, and air duct width, the revised analytical expression reduces the temperature rise error from 43.74% to 11.47% compared with the traditional empirical formula. Finally, the triple-constraint mechanism of “equal resistive voltage–equal loss density–equal encapsulation temperature rise” is proposed to balance interlayer current distribution, suppress total loss generation, and limit localized hotspot formation. A prototype constructed based on the optimized design demonstrates a 44.51% reduction in total loss, a 39.66% decrease in hotspot temperature rise, and a 24.83% reduction in mass while maintaining rated inductance, validating the effectiveness of the proposed design algorithm. Full article

Introduction: Stroke remains a major cause of disability worldwide, and precise identification of stroke lesions is essential for prognosis and rehabilitation planning. Machine learning has emerged as a powerful tool for automating stroke lesion segmentation and outcome prediction; however, these tasks are often studied in isolation. The two strategies are inherently interdependent since segmentation provides lesion-based features that directly inform prediction models. Methods: This narrative review synthesises studies published between 2010 and 2024 on the application of machine learning in stroke lesion segmentation and recovery forecasting. A total of 23 relevant studies were reviewed, including 10 focused on lesion segmentation and 13 on recovery prediction. Results: Convolutional Neural Networks (CNNs), including architectures such as U-Net, have improved segmentation accuracy on the Anatomical Tracings of Lesions After Stroke (ATLAS) V2 dataset; however, dataset bias and inconsistent evaluation metrics limit comparability. Integrating imaging-derived lesion characteristics with clinical features improves predictive accuracy at a higher level. Furthermore, semi-supervised and self-supervised methods enhanced performance where annotated datasets are scarce. Discussion: The review highlights the interdependence between segmentation and outcome prediction. Reliable segmentation provides biologically meaningful features that underpin recovery forecasting, while prediction tasks validate the clinical relevance of segmentation outputs. This bidirectional relationship underlines the need for unified pipelines integrating lesion segmentation with outcome prediction. Future research can improve generalisability and foster clinically robust models by advancing semi-supervised and self-supervised learning, bridging the gap between automated image analysis and patient-centred prognosis. Conclusion: Accurate lesion segmentation and outcome prediction should be viewed not as separate goals but as mutually reinforcing components of a single pipeline. Progress in segmentation strengthens recovery forecasting, while predictive modelling emphasises the clinical importance of segmentation outputs. This interdependence provides a pathway for developing more effective, generalisable, and relevant AI-driven stroke care tools. Full article

This paper presents a static-strength analysis of the construction of folding bridges, addressing in particular the dimensioning of pin connections. These connections are elements that transfer the axial forces between the chords of truss girders of connected span sections. First, the various components of folding bridges and the materials from which they are made are characterised. The characteristics of pin connections in modern folding bridge structures are discussed, including their influence on the static scheme of the entire structure. The parameters of such pin connections are presented in terms of both the strength of such a connection and cooperation of its components. The main part of this article is a detailed design analysis of the pin connection of the new MSC 23-150 “Cis” folding bridge structure, the concept of which was developed at the Faculty of Civil Engineering and Geodesy of the Military University of Technology. The calculations were carried out both analytically and with a spatial numerical model, which allowed us to determine the stresses on the connection components in the critical sections and propose the final shape of the connector. This article presents the effect of combining known methods of dimensioning pin connections and a method related to determining actual stress values by taking into account the so-called stress concentration factor in analytical calculations. Taking into account the real area of impact of the pin on the bridge pin joint element affects the stress concentration, which can cause an increase in stress in selected cases by up to 300%. Original results are presented on the relationship between individual stress values in specific cross-sections of the connection and the values of assembly clearances in prefabricated bridge structures, as well as their mutual relationships for specific values of assembly clearances. The above information is important when developing and operating bridges made of portable truss-type bridge structures. Knowledge of the phenomenon of stress concentration reduction when limiting assembly clearance allows for the safe and effective use and construction of this type of bridge structure. Full article

In this paper, we propose a novel visual tracking method with a object part-aware attention-based matching (OPAM) mechanism, which leverages local–global attention to enhance visual tracking performance. Our method introduces three key components: (1) a local part-aware global self-attention mechanism that embeds rich contextual information among candidate regions, enabling the model to capture mutual dependencies and relationships effectively, (2) a local part-aware global cross-attention mechanism that injects target-specific information into candidate region features, improving the alignment and discrimination between the target and background, and (3) a global cross-attention mechanism that extracts object holistic information from the target-search feature context for further discriminability. By integrating these attention modules, our approach achieves robust feature aggregation and precise target localization. Extensive experiments on a large-scale tracking benchmark demonstrate that our method shows competitive performance metrics in both accuracy and robustness, particularly under challenging scenarios such as occlusion and appearance changes, while running at real-time speeds. Full article

To effectively address challenges posed by high-penetration renewable energy to power system operation and reserves, this paper proposes a novel research framework. The framework considers transmission–distribution coordinated dispatch and optimizes reserve capacity. First, the framework addresses the volatility and uncertainty of wind and solar power output. It constructs a three-dimensional objective function incorporating generation cost, spinning reserve cost, and linear wind/solar curtailment penalties as core components. The study uses the IEEE 30-bus system as the transmission network and the IEEE 33-bus system as the distribution network to build a transmission–distribution coordinated optimization model. Power dynamic mutual support across voltage levels is achieved through tie transformers. Second, the framework designs three typical scenarios for comparative analysis. These include separate dispatch of transmission and distribution networks, coordinated dispatch of transmission and distribution networks, and a fixed reserve ratio mode. The approach breaks through the limitations of traditional fixed reserve allocation. It optimizes the coordinated mechanism between reserve capacity spatiotemporal allocation and renewable energy accommodation. Case study results demonstrate that the proposed coordinated optimization scheme reduces total system operating costs and wind/solar curtailment rates. This is achieved by exploiting the potential of regulation resources on both the transmission and distribution sides. The results verify the significant advantages of transmission–distribution coordination in improving reserve resource allocation efficiency and promoting renewable energy accommodation. The approach helps enhance power grid operational economics and reliability. Full article

As critical components in continental shale systems, the composition and evolution of clay minerals are fundamental to their diagenetic processes and petrophysical properties. The Chang-7 shales in the Ordos Basin exhibit abundant clay mineral content, offering a valuable case study for clay mineral research under moderate diagenetic conditions. This study employed XRD analysis to determine the whole-rock mineralogy, clay mineral composition, and the evolution characteristics of illite-smectite mixed-layer minerals (I/S). Comprehensive clay mineral datasets compiled from 13 newly analyzed wells and existing literature revealed distinct lateral distribution patterns. Total Organic Carbon (TOC) analysis and vitrinite reflectance (R_o) measurements provided systematic quantification of organic matter abundance and thermal maturation parameters in the studied samples. The results reveal that the Chang-7 shale exhibits a characteristic clay mineral assemblage, with I/S (average 44.2%) predominating over illite (34.7%), followed by chlorite (15.6%) and limited kaolinite (5.4%). Frequent volcanic activities provided substantial precursor materials for smectite formation, which actively participated in subsequent illitization processes, while chlorite and kaolinite distributions were predominantly controlled by provenance inputs and sedimentary facies, respectively. Inconsistencies exist between diagenetic stages inferred from I/S mixed-layer ratios and R_o values, particularly in low-maturity samples exhibiting accelerated illitization. The observed negative correlation between TOC content and mixed-layer ratios in Well YY1 and YSC Section samples demonstrates the catalytic role of organic matter in facilitating smectite-to-illite transformation. These results systematically clarify the coupled effects of sedimentary-diagenetic processes, offering new insights into the mutual interactions between inorganic and organic phases during illitization under natural geological conditions. The findings advance the understanding of Chang-7 shale oil and gas systems and offer practical guidance for future exploration. Full article

Gendered social protection interventions such as Let’s Talk are now appreciated as a significant component of family-based HIV prevention services. The intervention deliberately focuses on bridging the caregiver–adolescent relational and communication divides in the context of HIV prevention. This qualitative study used interviews to explore the caregivers’ parenting experiences after attending the Let’s Talk programme in Soweto, South Africa. Simple random sampling was used to select four Community-Based Organisations (CBOs). Twelve caregivers were purposively sampled from the four CBOs. Data analysis was accomplished through thematic analysis. The findings indicate that Let’s Talk had positive transformative effects on the caregivers’ parenting experiences and relational dynamics with adolescents. The improved parenting experiences were characterised by better communication, mutual respect and observed behaviour improvements by adolescents. In conclusion, caregivers’ reports of improved parenting experiences provide empirical evidence of acceptability to participants, effective implementation, and Let’s Talk’s efficacy in facilitating desired outcomes. Full article

Grafting constitutes a crucial approach for the preservation of pine clones. Slash pine is commonly used as the rootstock for grafting Masson pine scions in Guangxi. In this context, the fresh oleoresin samples of Masson pine, slash pine, and grafted pine (with Masson pine as scion and slash pine as rootstock) were analyzed by gas chromatography–mass spectrometry and gas chromatography, and the key chemical components (α-pinene, β-pinene, longifolene, and isopimaric acid) that can quickly and accurately distinguish the oleoresin of Masson pine and slash pine were found and identified. According to the changes in the relative content of key compounds of oleoresin in scion and rootstock, it was found that the oleoresin of rootstock and scion could interact. Further research showed that the mutual influence of oleoresin between rootstock and scion was persistent, and the influence of rootstock on oleoresin at the scion was affected by height. However, the height effect included a large individual differences, which were not significantly related to the grafting height, tree height, diameter at breast height, etc., but may have been related to the differences in synthesis speed of oleoresin between rootstocks and scions. This work reveals the possible mechanism of mutual influence and secretion of oleoresin in grafted pine trees, laying a foundation for the study of the characteristics of oleoresin from pines grafted by different types, with great significance for the breeding of pine with high yield of oleoresin, and the production and application of special compounds containing oleoresin. Full article

Noise in Pulsar Timing Array (PTA) data is commonly modeled as a mixture of white and red noise components. While the former is related to the receivers, and easily characterized by three parameters (EFAC, EQUAD and ECORR), the latter arises from a mix of hard to model sources and, potentially, a stochastic gravitational wave background (GWB). Since their frequency ranges overlap, GWB search methods must model the non-GWB red noise component in PTA data explicitly, typically as a set of mutually independent Gaussian stationary processes having power-law power spectral densities. However, in searches for continuous wave (CW) signals from resolvable sources, the red noise is simply a component that must be filtered out, either explicitly or implicitly (via the definition of the matched filtering inner product). Due to the technical difficulties associated with irregular sampling, CW searches have generally used implicit filtering with the same power law model as GWB searches. This creates the data analysis burden of fitting the power-law parameters, which increase in number with the size of the PTA and hamper the scaling up of CW searches to large PTAs. Here, we present an explicit filtering approach that overcomes the technical issues associated with irregular sampling. The method uses adaptive splines, where the spline knots are included in the fitted model. Besides illustrating its application on real data, the effectiveness of this approach is investigated on synthetic data that has the same red noise characteristics as the NANOGrav 15-year dataset and contains a single non-evolving CW signal. Full article