Search Results (19,676)

To address the existing problems of frequent manual tray handling, poor continuity, and insufficient coordination in fully automatic transplanters, this study designed an integrated multi-layer tray-handling and dual-claw coordinated seedling pick-and-throw mechanism. Through continuous tray conveying and multi-layer tray-handling mechanisms, automatic replacement of multiple seedling trays was achieved. A dual-claw coordinated seedling picking and planting mechanism was designed, and the seedling picking trajectory was optimized based on path planning and RecurDyn kinematic simulation. Six-segment and seven-segment S-shaped acceleration and deceleration motion control curves and planning strategies that can be switched according to the target displacement and dynamic parameters were proposed, and a PLC-based software and hardware control system was constructed. The simulation and experimental results show that the dual-module parallel motion mode is more efficient and has a smoother trajectory than the serial mode. The average positioning absolute error of tray conveying is 1.09 mm, the average horizontal and vertical positioning absolute errors of seedling picking are 1.07 mm and 1.09 mm, respectively, and the horizontal and vertical positioning absolute errors of seedling planting are 1.50 mm and 1.51 mm, respectively. The success rate of seedling picking is 97.01%, the success rate of seedling planting is 96.39%, and the qualified rate of planting is 96%. The experimental results meet the actual operation requirements. This study provides a theoretical basis and technical support for the high-efficiency coordinated operation of fully automatic transplanters. Full article

This study investigates the structure of innovation and entrepreneurship competence among university students in China. Based on an analysis of 33 policy texts on innovation and entrepreneurship education from 2010 to 2022, it constructs a structural model of university students’ innovation and entrepreneurship competence comprising the knowledge layer, ability layer, and literacy layer by employing the Onion Model. From the perspective of policy instruments, a two-dimensional competence–policy instrument analytical framework is established. The analysis reveals that the articulation of university students’ innovation and entrepreneurship competence in policy texts exhibits distinct stage-wise evolutionary characteristics. Furthermore, the current policy support system suffers from three structural imbalances: an over-reliance on supply-side policy instruments, with insufficient synergy from environmental and demand-side instruments; weak support from environmental and demand-side instruments for certain key competencies; and an emphasis on explicit knowledge over implicit literacy in the cultivation logic. Consequently, this study proposes a shift in the policy paradigm from factor input to system generation. Recommendations include optimizing the mix of policy instruments, improving the precision of interventions by environmental and demand-side instruments targeting key competencies, and reconstructing the cultivation system based on the different generative logics of explicit and implicit competence. Full article

While governance theories are well-established, their operational application to transboundary serial cultural heritage remains minimally explored, particularly regarding comparative methodologies for evaluating cooperation maturity. This study addresses this gap by investigating the relationships among institutional models, cooperation mechanisms, and management maturity levels across different countries. The research utilizes a qualitative comparative analysis of the management plans of fifteen transboundary serial cultural heritage sites on the UNESCO World Heritage List. Findings show that governance is not limited to the functioning of legal and administrative structures, but is also shaped by trust among stakeholders, knowledge exchange, and participant processes. Four main governance models were identified: institutionalized multinational networks, federal–modular structures, bilateral–local cooperation, and community-led collaboration. In parallel, the developed Corporate Governance and Maturity Positioning Map reveals that the sites fall along six distinct levels, ranging from basic communication to sustained governance networks. The study argues that the primary factor determining management effectiveness is the intensity of interaction and continuity of coordination rather than institutional capacity. Overall, the findings suggest that cultural heritage governance should be understood as a multi-layered, learning-based, and diplomatic process. Full article

Magnesium alloys require protective surface coatings for widespread application, with micro-arc oxidation (MAO) being a prominent technique. However, conventional MAO coatings are typically gray or light-colored, necessitating secondary treatments for specific colors like black, which complicates the process. This study aims to develop a one-step method for fabricating black MAO coatings on AZ31 magnesium alloy by introducing cupric pyrophosphate (Cu₂P₂O₇) as a colorant into a silicate-based electrolyte. As the Cu₂P₂O₇ concentration increased from 0 to 5 g/L, the coating color transitioned from grayish-white to pink, then brownish-black, achieving a uniform black appearance at 4–5 g/L. XPS and EDS analyses confirmed the incorporation of copper as CuO, identified as the primary coloring agent. XRD indicated that the phase composition remained MgO, MgSiO₃, and Mg, although the MgO content decreased. Microstructural analysis showed that an optimal concentration of 4 g/L enhanced coating compactness by thickening the dense layer and reducing pore size. However, electrochemical tests revealed that the incorporation of CuO significantly increased the corrosion current density, thereby reducing the coating’s corrosion resistance compared to the unmodified coating. This work successfully demonstrates the one-step fabrication of black MAO coatings, elucidates the coloration mechanism involving CuO formation, and provides insights into the trade-off between aesthetic functionalization and corrosion performance. Full article

Black crusts are multilayered alteration products that develop on historic masonry exposed to urban pollution. This study investigates the west enclosure wall of the XVII^th-century Golia Monastery in Iași, Romania—located along a busy traffic corridor—and presents multi-analytical results on two lime-based mortar fragments exhibiting well-developed blackened surface layers. Both the exposed (blackened) finishes and protected verso areas were analyzed using portable X-ray fluorescence (pXRF), scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX), micro-FTIR spectroscopy, X-ray diffraction (XRD), CIE Lab colorimetry and optical microscopy (OM). The data reveal gypsum-rich surface layers enriched in traffic-derived particles, including metal oxides and soot, with marked contrasts relative to the minimally altered verso. Handheld XRF and SEM–EDX indicate elevated sulfur and associated traffic-related elements within porous gypsum matrices, while FTIR and XRD consistently identify calcium sulfate as the dominant secondary phase. Colorimetric measurements additionally document pronounced lightness loss and visible darkening on exposed surfaces. These results demonstrate the onset of directional sulfation and black crust formation on mortars under urban pollution pressure and establish an integrated analytical protocol for diagnosing black crusts on historic lime mortars in urban heritage settings. Full article

The Internet of Things (IoT) is increasingly embedded in critical infrastructures across healthcare, energy, transportation, and industrial automation, yet its pervasiveness introduces substantial security and resilience challenges. This paper presents a comprehensive review of recent advances in IoT resilience, focusing on developments reported between 2022 and 2025. A layered taxonomy is proposed to organize resilience strategies across hardware, network, learning, application, and governance layers, addressing adversarial, environmental, and hybrid stressors. The survey systematically classifies and compares more than forty representative studies encompassing deep learning under adversarial attack, generative and ensemble intrusion detection, hardware and protocol-level defenses, federated and distributed learning, and trust and governance-based approaches. A comparative analysis shows that while adversarial training, GAN-based augmentation, and decentralized learning improve robustness, their evidence is often confined to specific datasets or attack scenarios, with limited validation in large-scale deployments. The study highlights challenges in benchmarking adaptivity, cross-layer integration, and explainable resilience, concluding with future directions for creating antifragile IoT systems that can self-heal and adapt to evolving cyber–physical threats. Full article

Background: Acute high-intensity noise exposure represents a critical environmental stressor; however, its impact on brain function and the underlying mechanisms remain incompletely understood. This study aimed to investigate the effects of acute high-intensity noise exposure on cognitive function in rats, utilizing multi-omics analysis to explore potential mechanisms. Methods: Rats were exposed to acute noise at 120 dB, and brain function was evaluated using the novel object recognition (NOR) test, recordings of electroencephalographic activity, and histopathological examination. Longitudinal serum metabolomics and fecal metagenomics were performed on samples collected at 0 h, 7, 14, and 28 days post-exposure. Quantitative profiling of oxylipins and proteomics were conducted at a critical time point, followed by integrative multi-omics network analysis. Results: Acute high-intensity noise exposure significantly reduced the recognition index in the NOR test, increased theta-band power, and induced hippocampal neuronal damage. Multi-omics analyses revealed time-dependent alterations in gut microbiota and metabolic profiles, identifying day 7 as the critical response window, with arachidonic acid (AA)-derived metabolites consistently downregulated across omics layers. Integrated analysis revealed a coordinated microbiota–oxylipins–proteins network, highlighting key AA-derived oxylipins (e.g., 8-HETE, 12-HETE) that correlated with specific gut microbiota and proteins involved in lipid metabolism and inflammation. Conclusions: Acute high-intensity noise exposure induces cognitive impairment and systemic molecular disturbances. AA-centered lipid metabolism acts as a key hub linking gut microbiota dysbiosis with inflammatory and metabolic protein alterations, providing multi-omics evidence for coordinated microbiota–lipid–protein dysregulation underlying noise-induced neurobiological dysfunction. Full article

Rising concentrations of organic carbon (OC), phosphorus, and nitrogen in liquid waste from urban, industrial, and agricultural sources pose persistent challenges for environmental protection and resource recovery. Despite extensive application of microfiltration (MF) and ultrafiltration (UF) in wastewater treatment, their role in selective organic carbon and nutrient fractionation remains insufficiently clear-cut and is often interpreted solely through nominal pore size. This review was guided by the hypothesis that the reported limitations of MF and UF for nutrient separation are not intrinsic to the technologies but arise from simplified interpretations of separation mechanisms. A unified analytical framework was developed by synthesizing recent studies, linking membrane surface charge, pore structure, solute speciation, fouling-induced secondary layers, and operating conditions to the observed separation behavior. The analysis shows that MF fractionates particulate OC and suspended solids, whereas UF extends separation to macromolecular OC and phosphorus mainly via indirect retention mechanisms. Dissolved nitrogen species largely permeate both membranes unless they are transformed into retainable forms. Performance differences between MF and UF are conditional and system-dependent, with enhanced selectivity emerging through process integration. MF and UF can thus be repositioned as strategic fractionation interfaces within integrated treatment systems supporting circular economy–oriented wastewater management. Full article

Integrated Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) studies were performed to identify potential tin (Sn) mineralization prospects in the Eastern Tin Belt of Peninsular Malaysia. A total of 23 profiles were obtained utilizing a Schlumberger configuration, generating resistivity and chargeability sections employed to delineate weathering structures, lithological connections, and structurally regulated anomalies. ERI models consistently delineate a three-tier subsurface structure consisting of conductive soil/alluvial deposits (5–300 Ωm), weathered bedrock (300–1500 Ωm), and resistive fresh bedrock (>1500 Ωm), featuring undulating basement relief beneath floodplain layers. IP data indicate localized, often pronounced chargeability anomalies (~5–40 ms; locally reaching ~50 ms), interpreted as corridors influenced by fractures and veins, especially when they align with significant resistivity contrasts at metamorphic–granitic boundaries and intrusive contacts. The integration of fence diagrams in the alluvial-over-granite zone reveals laterally consistent chargeability peaks at the alluvial–bedrock interface, suggesting enduring subsurface conduits. XRF examination of quartz-vein samples verifies Sn enrichment (599–717 ppm), corroborating a granite-related vein/alteration hypothesis and indicating possible isolated greisenized zones within the weathered granite. The integrated ERI–IP analysis identifies priority targets for subsequent trenching and borehole drilling to verify an anomaly’s origins and evaluate Sn grade and continuity. Full article

Runoff forecasting is an essential application in the management of water resources and sustainable development. In practice, there are limitations in the forecast results because of factors such as data unavailability, noise interference, and spatiotemporal variation in multi-site data. To overcome the limitations, this paper proposes a hybrid forecast model based on Autoencoder (AE), Sparsified Dynamic Graph Convolution (SDGC), and Autoformer. The AE cleans noise and sharpens feature representation, the SDGC constructs dynamic adjacency matrices via the Multidimensional Dynamic Time Warping (MDTW) and sparsifies with a parameterized Multi-Layer Perceptron (MLP) to capture time-varying spatial correlations among stations, and the Autoformer decomposes features to model long-term nonlinear runoff trends through its autocorrelation mechanism. The experiment was carried out in six locations in the southeastern part of Guizhou province during the wet and dry periods and was contrasted with different mainstream models and supplemented with hydrological mechanism consistency analysis. Experimental results show that the hybrid model performs better than all the other models. In the short-term runoff simulation at XingHua Station during the wet season, NSE attains the maximum value of 0.891, with RMSE decreased by 6.5% to 24.1% and MAE by 20.2% to 35.5%. This model provides accurate runoff data to support flood early warning, dry-season water scheduling, and ecological flow protection, offering a reliable tool for sustainable water resource management in complex karst basins. Full article

Background/Objectives: This study investigates the normative data and determinants of retinal and choroidal vessel density (VD) in Tibetan children using optical coherence tomography angiography (OCTA). Methods: This study recruited students from primary schools in Lhasa who underwent OCTA encompassing VD in the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) and choriocapillaris (CC) in the macular region, as well as refractive status, axial length, and systemic examinations. Results: This study included a total of 645 children who met the criteria. The results showed that VD in the fovea was significantly higher in the SCP than in the DCP, while CC had the highest VD in the fovea. Correlation analysis revealed strong correlations in VD among all quadrants of the SCP, DCP, and CC, as well as significant correlations between corresponding regions of the SCP and DCP. VD showed no significant association with age, sex, axial length, or spherical equivalent. Foveal VD in both the SCP and DCP was positively correlated with oxygen saturation. No consistent correlation was found between choroidal or retinal thickness and VD in any layer. Conclusions: The identified link between systemic oxygen saturation and foveal vascular density offers a novel perspective on human adaptation to chronic hypoxia, positioning the retinal microcirculation as a sensitive indicator of systemic oxygen homeostasis. Full article

In this study, boron carbide (B₄C), hexagonal boron nitride (hBN), holy super graphene (HSG), and hybrid (B₄C+hBN+HSG) nano-additives were added to SAE 15W-40 diesel engine oil at a range of 0.03–0.24 g per 30 mL of oil, and reciprocating tribological tests were conducted on a GG25 (EN-GJL-250) gray cast iron-based diesel piston surface in contact with an Al₂O₃ ball (Ø6 mm) at a load of 20 N, a sliding distance of 500 m, and a temperature of 75 °C. XRD analysis showed that the dominant phase on the piston surface was the α-Fe matrix and that no significant new phase had formed. The results obtained revealed that the nano-additive effect is strongly dependent on both the additive type and the additive level. At a low level (0.03 g/30 mL) of B₄C additive, the average COF decreased by approximately 19%, while at a low level (0.03 g/30 mL) of hBN additive, this decrease amounted to approximately 54%. In the HSG additive, at the highest level (0.24 g/30 mL), the coefficient of friction (COF) decreased to ≈0.032, achieving a friction reduction of approximately 75% compared to the base oil. In the hybrid oil series, COF values remained in the range of approximately 0.082–0.087 at all additive levels and were generally 25–28% lower than those of the base oil. SEM/EDS examinations showed that a tribofilm with high carbon content formed in the HSG-additive oils, while a tribofilm layer containing C, B, and N elements together formed in the hybrid-additive oils. Overall, it was concluded that selecting the appropriate additive type and level can reduce friction and wear losses at the piston interface, thereby contributing to engine efficiency by extending the life of engine components and limiting friction-induced energy losses. Full article

Currently, standardized classification methods of surrounding rock are relatively insufficient. The classification of surrounding rock mainly relies on the subjective judgment of technicians, leading to diverse evaluation results. This study focuses on the feature extraction and classification methods of surrounding rock images in a certain tunnel of the Central Yunnan Water Diversion Project by using image processing analysis and transfer learning. Rich surrounding rock images and the water conservancy tunnel data are collected, and then the surrounding rock is classified relatively accurately according to the code and expert guidance. By introducing the fractal theory, the complexity and irregularity of the spatial distribution of weak layers and joints on the surrounding rock surface are revealed effectively. Based on the analysis of changes in fractal dimension characteristic values, a classification method for surrounding rock based on the fractal theory is proposed. Combined with the quantified parameters of surrounding rock images and the strength data collected by rebound meters, a method for correcting the surrounding rock strength based on image analysis is proposed, which can effectively solve the error caused by the uneven distribution of rock masses in the traditional rebound meter strength values. After correction, more accurate strength characteristics can be obtained, which is conducive to the standardized classification of the surrounding rock. After studying the recognition of tunnel surrounding rock images with transfer learning, a model is constructed to achieve rapid classification of tunnel surrounding rock. This research provides support for the standardized classification of tunnel surrounding rock. Full article

Low-Power Wide-Area Network (LPWAN) technologies play a central role in large-scale wireless sensor network (WSN) deployments, where energy efficiency, coverage and reliability dominate over throughput. Among them, Long Range (LoRa) technology has emerged as a widely adopted physical-layer solution due to its ability to operate at extremely low signal-to-noise ratios (SNRs). While multi-antenna techniques can potentially enhance link performance, their applicability in LoRa-type systems is constrained by low-SNR operation, strict energy budgets and the quality of channel state information (CSI). This paper presents a systematic and progressively structured evaluation of multiple-input multiple-output (MIMO) techniques in LoRa-type systems under representative operating conditions. A multi-stage simulation framework, implemented using the Vienna SLS v2.0 (Q3) simulator and adapted to LoRa-like waveforms, is employed to isolate the impact of large-scale propagation, small-scale fading, antenna configuration and CSI quality. The analysis starts from a system-level coverage baseline and advances to link-level evaluations of diversity-oriented MIMO schemes and spatial multiplexing configurations under both ideal and imperfect CSI. The results demonstrate that spatial diversity techniques are well aligned with the operational characteristics of LoRa links, offering robust performance in low-SNR regimes and under limited CSI accuracy. In contrast, spatial multiplexing exhibits higher sensitivity to channel estimation errors, with its practical benefits becoming apparent primarily when evaluated using throughput-oriented metrics such as packet error rate and normalized goodput. Overall, the study highlights the fundamental trade-off between reliability and capacity in LoRa MIMO systems and provides design-oriented insights for wireless sensor network deployments. Full article

Carbon fiber-reinforced plastics (CFRP) are widely used in deployable space structures due to their strength-to-weight ratio, yet their inherent brittleness and limited damage tolerance constrain their performance under large deformation. This study reports a new concept, the Kevlar composite deployable lenticular tube (CDLT), for improved toughness and reliable stowability. The buckling response of Kevlar CDLT under axial compression and torsion was characterized, and its stowability was verified through experiments and finite element analysis (FEA). Axial compression studies show that the load–displacement curve transitions from linear elastic to nonlinear deformation at the critical buckling load; meanwhile, local stress magnification occurs in the central arc region. Damage analysis further reveals that buckling instantaneously induces localized wrinkling and matrix failure. Torsional analysis shows that the CDLT exhibits an initially linear torque–twist response, governed by shear stiffness. However, once the critical torque is exceeded, torque decreases sharply due to localized collapse and overall buckling. Moreover, the outermost layers bear the highest stresses, whereas the inner layers remain comparatively uniform and less stressed. Furthermore, the influence of different layup sequences, ply numbers, and total thickness on the load-bearing capacities of CDLT was investigated, ultimately determining the optimal layup scheme. Finally, the stowability analysis demonstrates that the Kevlar CDLT, configured as a six-ply laminate with a total thickness of 0.72 mm, achieves an optimal balance between stiffness and flexibility. In this comparison, both the Kevlar and CFRP CDLTs employ identical lenticular cross-sectional geometries, fully consistent boundary conditions, the same overall laminate thickness (0.72 mm), and an identical stacking sequence of [45°/−45°/90°/90°/45°/−45°], with the material properties being the only variable. Under these strictly controlled conditions, the coiling torque of the Kevlar CDLT is reduced by at least 48% relative to that of the CFRP CDLT. This study preliminarily verifies the load-bearing capacity and stowability of novel Kevlar CDLTs, providing valuable guidance for the design of deployable space structures. Full article