Search Results (2,618)

To address the issues of poor operational stability and insufficient omnidirectional leveling capability of tracked electric agricultural machinery in hilly and mountainous areas, this paper presents an electromechanical omnidirectional leveling chassis architecture based on a dual-layer independently driven architecture. Utilizing servo electric cylinders as actuators, a leveling mechanism with physically decoupled upper lateral and lower longitudinal layers was constructed. Based on this structure, a mathematical model relating the electric cylinder displacement to the platform posture was established. Furthermore, an ADAMS dynamics simulation platform was built to conduct simulation analysis and prototype experiments. The results indicate that the designed dual-layer independently driven chassis can achieve a theoretical leveling range of ±28.6° laterally and ±27.7° longitudinally, operating smoothly under the rated 25° slope condition. Dynamic tests demonstrate that when the prototype travels at 3 km/h, the residual inclination angle of the platform can be controlled within ±0.9° in 3 s. The simulation and experimental results are in high agreement, comprehensively revealing the dynamic coupling relationship among the electric cylinder displacement, platform posture, and driving thrust. The experiments verify that the electromechanical omnidirectional leveling system can accomplish adaptive leveling under slope conditions, exhibiting superior performance regarding response speed, control accuracy, and disturbance rejection, with the thrust deviation rate between simulation and experiment within 6.71%. Full article

Aiming at the problem of the insufficient passability and stability of the tracked chassis of silage harvesters caused by complex hilly and mountainous areas and a severe working environment, the crawler chassis of self-propelled silage harvesters was taken as the research object, the straight-line driving, longitudinal climbing, and lateral climbing processes of the chassis were theoretically analyzed, and the critical parameters that affect the normal climbing of the chassis were calculated. Meanwhile, the multi-body dynamics model of the tracked chassis was established by using the software SolidWorks 2020 and RecurDyn 2023, and its climbing and obstacle crossing performance were analyzed. The relevant motion parameters of the tracked chassis suitable for longitudinal and transverse slopes in hilly and mountainous areas were obtained, and field tests were conducted on the tracked chassis to verify the reliability of the simulation model. According to the simulation results, the tracked chassis achieves ultimate slope angles of 28° longitudinally and 23° laterally. It demonstrates the capability to navigate 140 mm high ridges and 250 mm wide trenches smoothly, while its straight-line driving offset rate conforms to prevailing agricultural machinery industry standards. Field test results indicated that the tracked chassis achieved a maximum longitudinal climbing angle of 26°. The relative error of less than 8% between the experimental and simulated data confirms a strong correlation. The maximum offset rate for straight-line travel is 1.95%, meeting the requirements of the agricultural machinery industry standards. The test verified the feasibility of the dynamic model of the crawler chassis of the silage harvester, providing a theoretical basis and technical support for the optimal design of the crawler chassis of the self-propelled silage harvester in hilly and mountainous areas. Full article

Coastal alluvial plains underlain by unconsolidated deposits are prone to land subsidence, a geohazard that can damage infrastructure and alter drainage patterns. One such example is the Venetian–Friulian coastal plain (NE Italy), where natural sediment compaction and anthropogenic activities have led to ground deformation across multiple zones. From this perspective, this study presents a 30-year analysis of land subsidence across the Venetian–Friulian plain, particularly highlighting municipalities such as Portogruaro, Concordia Sagittaria, San Stino di Livenza, Eraclea, and Caorle. The dataset comprises multi-source SAR data from ERS, Envisat, COSMO-SkyMed (CSK), Sentinel-1, and the European Ground Motion Service (EGMS), covering the period from 1992 to 2021. The study integrates multi-platform SAR observations with ADAFinder-based extraction of Active Deformation Areas (ADAs), data quality evaluation using the Quality Index (QI), building-scale analysis based on LOS-derived vertical displacement time series, and orthophotos to confirm the building’s presence and evolution. By using the adopted extraction thresholds, a total of 57, 16, 83, 33, and 72 ADAs were identified from the ERS, ENVISAT, COSMO-SkyMed, Sentinel-1, and EGMS datasets, respectively. The result suggests that the strongest deformation occurred during the earlier observation periods in Zones 1 to 3, then progressively stabilized, whereas some parts of Zone 4 remained active and showed renewed deformation during the later periods. The research highlights the importance of conducting long-term analysis using multi-platform interferometric datasets to refine and personalize outcomes in geohazard monitoring. The findings from this research offer invaluable insights into the ongoing surveillance of geohazards, which are progressively related to urban development and planning. Full article

Over the last two decades, there has been a paradigm shift in geotechnical engineering driven by advances in sensing, communication, and data-driven techniques. These advancements enhanced the safety and reliability of geotechnical infrastructure through real-time monitoring and automated decision-making. In recent times, Large Language Models (LLMs) have emerged as advanced data-driven techniques contributing to automated risk assessment of geotechnical infrastructure. LLMs are advanced deep learning models widely used to solve complex numerical problems, analyze large volumes of data, and generate human language. This paper presents a critical review of the application of LLM in geotechnical engineering. The integration of LLMs into geotechnical engineering has demonstrated significant advances in slope stability analysis, bearing capacity computation, numerical analysis, soil–structure interaction, and underground infrastructure. By summarizing the latest research findings and practical applications, this research paper underscores the potential of LLMs to advance and automate various processes in geotechnical engineering. The findings presented in this paper not only provide insights into the current LLM-based geotechnical practices but also emphasize the instrumental role that LLM can play in advancing geotechnical engineering, ultimately ensuring a safer and more sustainable future. Lastly, this paper highlights the different LLM capabilities which can be used to empower geotechnical engineers. Full article

Tailings management presents a critical challenge for the mining industry, particularly in mountainous regions with high seismicity and steep slopes. This article presents the development and design criteria for dry stacking of filtered tailings as a sustainable and safe alternative to conventional slurry tailings storage facilities (TSFs). The study focuses on the extreme conditions of a mountainous location characterized by complex topography with 10% slopes, space constraints, and significant seismic activity defined by a peak ground acceleration (PGA) of 0.3 g. The design methodology, which incorporates layered compaction of the filtered tailings to achieve a geotechnically stable structure, is detailed for a filtered TSF consisting of 7 terraces, each 10 m high, reaching a total height of 70 m. This approach minimizes the risk of liquefaction and prepares the filtered tailings surface for progressive closure, with unit operating costs (OPEX) of 2.5 USD/t. The results of the physical stability analysis confirm the viability of this solution: pseudo-static stability analysis yielded a safety factor of 1.22, demonstrating a significant reduction in water consumption and potential environmental impact. It is concluded that the dry disposal of filtered tailings is a technically robust option for tailings management in extreme mountainous environments, offering greater long-term safety guarantees and facilitating landscape integration, thus setting a precedent for mining projects in similar geographies. Full article

Slope displacements (δ) have been shown to correlate uniquely with the earthquake energy (E_eq) contributing to slope sliding, regardless of input motion characteristics. Based on this principle, this study applies the Energy-Based Newmark Method to infinitely long slopes subjected to ten diverse earthquake records with stepwise scaled amplitudes. As the earthquake wave energy (Eᵤ) increases, the energy ratio (E_eq/Eᵤ) exhibits a distinct peak followed by a monotonic decrease. The peak values and corresponding Eᵤ levels strongly depend on the predominant frequencies (f_p) of the motions, consistent with results from harmonic wave analyses. A unified design diagram is developed to correlate E_eq/Eᵤ with Eᵤ, incorporating f_p and slope parameters. Since both Eᵤ and f_p can be determined from design motions or empirically predicted using earthquake magnitudes and source distances, the slope displacement δ can be directly obtained from the diagram, eliminating the need for time-domain numerical simulations used in the conventional Newmark approaches. This method is recommended to conduct seismic zonation and hazard mapping in mountainous and hilly regions for regional authorities and infrastructure planners. Full article

Time-series machine learning models represented by long short-term memory (LSTM) networks provide an effective way to obtain high-precision sound speed profiles (SSPs) quickly and at low cost, which can meet the practical application requirements of underwater sonar systems. However, in sea areas with frequent strong internal solitary waves, the large-amplitude sound speed anomalies caused by them will seriously interfere with model learning in the form of strong outlier features, resulting in a sharp drop in SSP prediction accuracy and significant degradation of the generalization stability and robustness of the model. To address this problem, this paper proposes a time-series SSP prediction method based on a bidirectional long short-term memory (Bi-LSTM) network. First, Empirical Orthogonal Function (EOF) decomposition is used to realize the low-dimensional feature representation of SSPs, and then the bidirectional time-series feature capture capability of Bi-LSTM is used to predict the SSP sequence with large disturbances caused by strong internal solitary waves. Multiple groups of comparative experiments based on the measured temperature chain data in the continental slope area of the South China Sea show that the Bi-LSTM model has a significant improvement in prediction accuracy and robustness compared with the classical LSTM model. Among them, the Bi-LSTM model with EOF decomposition achieves a correlation coefficient of 0.995 and an average Root Mean Square Error (RMSE) as low as 0.387 m/s. Under the condition of internal solitary wave disturbance, the classical LSTM is difficult to effectively capture the large abrupt change in sound speed, while the proposed Bi-LSTM model can still achieve accurate prediction of the SSP in the disturbance section, and has both the feature recognition and evolution prediction capabilities for the strongly nonlinear internal solitary wave process. This method provides effective technical support for the rapid and large-scale reconstruction of the sound speed field under the disturbance of strong internal solitary waves. Full article

Net primary productivity (NPP) and its response to global climate change are one of the hot topics in global change research. Based on Net primary productivity remote sensing data and meteorological data, this study analyzed the spatiotemporal variation in vegetation NPP in Maowusu sandy land by using Sen trend analysis, Mann–Kendall significance test, coefficient of variation stability analysis, partial correlation and complex correlation analysis, and quantitatively analyzed the response of vegetation NPP to climate factors. The results showed that from 2001 to 2023, the overall vegetation NPP showed a significant upward trend, and the annual average increased from 124.28 g·(m⁻²·a)⁻¹ to 221.41 g·(m⁻²·a)⁻¹. The Theil–Sen median slope of NPP was +3.87 g·(m⁻²·a)⁻¹ with a coefficient of variation (CV) of 0.19, suggesting a robust but spatially variable greening trend. In total, 98.53% of the area showed an upward trend, with a very significant and significant increase area. The overall stability of vegetation NPP was strong, with an average coefficient of variation (CV) of 0.19 and a CV< of 0.30 in 97.96% of the regions, but the local area from southwest to east was highly volatile and there was a risk of secondary desertification. The influence of climate factors on vegetation NPP had significant spatial heterogeneity: precipitation was the key driving factor, and most areas were positively correlated. Potential evapotranspiration was positively correlated in the central and northern regions, and negatively correlated in some southern areas. The overall temperature has a negative effect, and only the local area has a weak promoting effect. Multi-correlation analysis shows that vegetation NPP is the result of the synergy of multiple climatic factors, and the hydrothermal coupling mechanism plays a decisive role in its spatial pattern. This study can provide a scientific basis for the restoration of vegetation ecosystems, environmental protection policy formulation, ecological protection and high-quality development of the Yellow River Basin in Maowusu Sandy Land. Full article

Background: Hippotherapy, a sensorimotor-rich intervention proposed for children with Autism Spectrum Disorder (ASD), is suggested to influence executive function (EF). However, the underlying electrophysiological mechanisms, particularly changes observed in resting-state Electroencephalography (EEG), remain underexplored. Methods: A total of forty-eight children with ASD, aged 9–12 years, participated in this quasi-experimental, non-randomized pre-test–post-test study. Participants were assigned to either a standardized 12-session hippotherapy program (n = 24) or a waitlist Control group (n = 24). EF was evaluated pre- and post-intervention using validated measures: the Wisconsin Card Sorting Test, Stroop Color–Word Test, Corsi Block-Tapping Task, and Tower of London. Resting-state EEG data (19 channels, 250 Hz) were recorded before and after the intervention and analyzed for spectral power, pairwise Pearson correlation, phase-based functional connectivity using the Phase Lag Index (PLI), and directed effective connectivity using Phase Transfer Entropy (PTE). EEG effects were tested with linear mixed models in MATLAB (fitlme), with the measured values in each ROI as the dependent variable, group and time as fixed effects, and SubjectID included as a random intercept; EF outcomes were analyzed with ANCOVA/MANCOVA, adjusting post-test scores for baseline. The assumptions of homogeneity of slopes, Levene’s test, and the Shapiro–Wilk test were examined, and the Holm–Bonferroni correction together with partial η² effect sizes were reported. Results: Following baseline adjustment, the hippotherapy group showed substantial and statistically significant improvements across all EF measures compared with controls partial η² range = 0.473–0.855; all adjusted p < 0.001; e.g., Stroop Incongruent Reaction Time (F(1,45) = 265.80, p < 0.001, ηp² = 0.855). EEG analyses revealed localized Group × Time interaction effects involving frontal delta power as well as selected alpha-, theta-, and beta-band connectivity measures within frontally anchored networks. In addition to these focal interaction effects, the hippotherapy group exhibited a narrower distribution of pre–post EEG changes across spectral power and connectivity metrics compared with controls, indicating greater temporal consistency in resting-state electrophysiological dynamics across sessions. Because group allocation was non-random (based on scheduling feasibility and parental preference), results should be interpreted as associations rather than causal effects. While the hippotherapy group exhibited significant EF improvements and relative stabilization in EEG spectral and connectivity metrics, particularly in frontal delta/theta/alpha/beta bands, a direct mapping between individual EEG changes and behavioral gains was not observed. Conclusions: A standardized 12-session hippotherapy program was associated with substantial improvements in EF and with relative stabilization of resting-state electrophysiological dynamics in children with ASD. However, the direct mechanistic link between these EEG and behavioral changes warrants further investigation. Larger randomized trials employing active control conditions, task-evoked electrophysiological measures, and extended longitudinal follow-up are needed to confirm efficacy, clarify mechanisms, and establish the durability of effects. Full article

High Andean lagoons in southern Peru have critical hydrological and ecological functions; however, long-term time series integrating trophic, integral quality, and metal contamination metrics to support adaptive management are lacking. A total of 1846 records (2015–2024) from four systems (3100–4600 m a.s.l.) were analyzed using seven indices assessing trophic status (TSItsr, TRIX), general water quality (OWQI, WQIHA, CCME-WQI), and metal contamination (HPI, CD). Temporal trends were assessed using Mann–Kendall and Theil–Sen slope; spatial heterogeneity using Kruskal–Wallis and Dunn–Bonferroni comparisons; controlling factors using distance-based redundancy analysis (999 permutations); and functional typology using Ward’s hierarchical clustering on Z-standardized data. 93% of the series lacked monotonic trends (52/56 lagoon–stratum × index combinations), demonstrating high interannual stability; spatial variance was marked (ε² = 0.73 in CCME-WQI). Distance-based redundancy analysis (db-RDA) explained 24.6% of total variability, with lake identity as the dominant driver (~45%), followed by temporal change (~8%). Four functional archetypes emerged, including a metal-eutrophic hotspot (HPI ≈ 213; CD ≈ 19) and recovering reservoirs with intermediate water quality indicators. Joint thresholds (TSItsr ≥ 60 + HPI ≥ 100) establish early-warning criteria, with Paucarani (HPI = 213) approaching the critical domain where metal-driven stress may facilitate cyanobacterial dominance. Systems show temporal resilience but strong spatial divergence induced by local pressures. The proposed typology and thresholds provide an operational basis for early warnings and prioritization of remediation actions in high-mountain ecosystems subject to increasing anthropogenic stress. Full article

The rapid advancement of high-technology industries critically depends on the supply of rare earth elements (REEs), which constitute strategic raw materials for knowledge-intensive sectors. This study proposes an integrated methodological framework for the development of the Kundybay REE deposit, combining geomechanical substantiation of open-pit slope stability with beneficiation optimization of weathering-crust ores. The novelty of the research lies in the justification of rational pit-wall parameters based on a coupled 3D geological–geotechnical model implemented in the Micromine environment. Structurally disturbed zones were identified and subjected to detailed stability analysis using numerical modeling techniques. Particular emphasis was placed on the delineation of geotechnical domains and factor-of-safety evaluation in Slide2, which enabled refinement of design solutions and optimization of slope geometry. Simultaneously, the study addresses processing challenges of refractory weathering-crust ores through the application of ultrasonic aerohydraulic desliming combined with a vibro-centrifugal separation device. Optimization of slope parameters resulted in a 30 Mt reduction in stripping volume, corresponding to a 16.7% economic gain. The proposed flowsheet achieved a concentrate grade of 948.89 g/t REEs with an overall recovery of 45.66%. The results confirm that integrating geomechanical design with process engineering provides a technically robust and economically efficient basis for REE deposit development. Full article

Sub-harmonic oscillations are a key stability concern in fast-switched inductor power supplies using clocked constant-period peak/valley-current loops. Using generalized models, IC designers can predict and suppress sub-harmonic oscillations with minimal overhead. This work presents an insightful, generalized, and comprehensive time-domain analysis of sub-harmonic oscillation propagation and suppression via slope compensation in constant-period peak/valley-current control. Since it is unstated and unvalidated in the literature, an exact, easy-to-apply expression for the slope compensation boundary is derived in terms of basic circuit operating parameters, showing that it is half of the difference in the drain and energize slopes in peak mode, and half of the difference in the energize and drain slopes in valley mode, lying beyond the conventionally accepted half drain (peak) and energize (valley) slope criteria. The prior literature also does not account for the impact of parasitic resistances on the duty-cycle-based stability boundary beyond which sub-harmonic oscillations begin. We address these gaps and establish a theoretical basis for the absence of sub-harmonic oscillations in DCM. Additionally, existing approaches to slope selection ensure stability but do not target the rate of suppression. We address this by proposing a compensation slope that achieves 90% suppression of the initial imbalance within three switching periods. Full article

Utilizing excavated waste soil to level gullies offers significant advantages in terms of engineering economy and construction efficiency. However, the stability and deformation risks of high-fill embankments in mountainous gullies under rainfall conditions have attracted significant attention, particularly when such structures are located adjacent to residential areas. This study compares two design schemes for highway high-fill embankments, Scheme 1: high-fill slope supported by stabilizing piles and prestressed anchors, and Scheme 2: ordinary waste soil as the core, foamed lightweight soil (EPS) as the edge band, and reinforcement by a micro-pile retaining wall system. Finite element analysis was used to evaluate the Factor of Safety (FOS), displacements of retaining structures, and characteristic slope points under three conditions (no rainfall, heavy rainfall, and heavy rainfall with soil strength deterioration). The results show that Scheme 2 reduces total costs by 3.5%, shortens the construction period by 14%, and cuts maintenance costs by 65%, with a minimum FOS of 1.56 under extreme rainfall. Further parametric analysis of Scheme 2 optimized key design parameters, and field monitoring data over 6 months verified the reliability of the numerical simulation. This study provides a transferable design-verification pathway for combining lightweight and conventional fills in high embankments, offering technical support for similar projects in complex mountainous areas. Full article

Deep-seated landslide complexes are widespread in soft-rock hill-country landscapes, yet their regional morphometric organisation and controlling factors remain insufficiently quantified. This study uses high-resolution (1 m) airborne LiDAR-derived terrain data integrated with geological and drainage-network datasets to investigate landslide complexes in the eastern Tararua District, New Zealand. A relative, unit-based morphometric framework is applied to compare terrain derivatives (including slope, aspect, and multi-scale relative relief) between mapped landslides and their host geological units. To isolate intrinsic lithological controls from geomorphic influences, the analysis is restricted to landslides occurring entirely within a single geological unit. The results indicate that lithology exerts first-order control on landslide morphometry, while fluvial incision and valley confinement regulate landslide initiation and persistence. Landslides are preferentially associated with low- to mid-order channels, indicating strong hillslope–channel coupling within a young, actively uplifting landscape. A conceptual threshold framework is proposed, showing that landslides develop where lithological susceptibility and relief amplification jointly exceed stability thresholds. By integrating geological information with LiDAR-based morphometric analysis, this study provides a transferable framework for distinguishing instability regimes and improving understanding of sediment dynamics and landscape evolution in soft-rock terrains. Full article

Submarine canyon-channel systems play a critical role as potential conduits for warm-water upwelling around Antarctica, potentially influencing ice-sheet stability. Integrating multibeam bathymetry, seismic profiles, and morphometric analysis, this study identifies 29 canyon-channel systems along the Adélie Land margin and reveals clear morphological contrasts between the Adélie Depression and the Adélie Bank. Systems in the Depression are elongated, slightly sinuous, and dendritic, with downstream increases in width-to-depth ratio, whereas those on the Bank are shorter, isolated, and single-branched, with irregular along-thalweg variations. Mann–Whitney U tests show significant differences in sinuosity and thalweg gradient (p < 0.01). These contrasts reflect the combined effects of shelf-slope topography, sediment supply, and ice-sheet dynamics. In the Depression, steep slopes, focused glacial sediment input from the Wilkes Subglacial Basin, and associated progradational wedges and mass transport deposits promote mass failures and turbidity-current incision. Strong correlations among canyon-channel length, width, and depth indicate coherent scaling under concentrated sediment supply. In contrast, gentler slopes and lower sediment input on the Bank produce simpler systems. These results highlight how glaciated-margin canyon morphology records coupled sedimentary and ice-sheet–ocean processes. Full article