Search Results (704)

Compared with the Earth’s surface, geostationary orbital (GEO) targets are relatively static, which makes it difficult to obtain two-dimensional radar images when the radar is ground-based without movement. This paper proposes an imaging method for GEO targets based on ground-based Multiple-Input Multiple-Output (MIMO) radar. It combines multiple ground-based radars distributed across the Earth’s surface to image GEO targets. When the virtual aperture of the MIMO radar is planar, three-dimensional imaging results can be obtained. First, the ground-based MIMO radar imaging scenario for GEO targets is introduced, and an analysis of the azimuth resolution is performed. Subsequently, a Three-Dimensional Target-Oriented (TDTO) coordinate system is established. The back-projection (BP) algorithm is then employed to reconstruct the target image. Finally, simulations are conducted and analyzed, including cases of a single-point target, multiple scatterers of a satellite model, and full-wave radar echo simulation using CST. The results show that when the center frequency is 35 GHz, and the baseline length is 1500 km, azimuth resolution of the imaging is better than 0.1 m. Full article

The economic importance of Carlin-type gold deposits is complicated by the concealed nature of stratiform gold-bearing zones and their occurrence at depths of several tens of meters or more below the present-day surface. This necessitates the use of a wide range of technologies and unconventional, including cost-effective and environmentally friendly, exploration methods to delineate potentially prospective areas. This study explores the possibilities of applying remote sensing methods to organize prospecting and exploration activities for targeting Carlin-type deposits in a more efficient and cost-effective way. The location of Carlin-type gold deposits within areas of orogenic and post-orogenic magmatism, mantle plumes, and linear crustal structures—as demonstrated by previous research in the Nevada and South China metallogenic provinces—may serve as a basis for developing a conceptual model of their distribution. To this end, we developed the GeoNEM (Geodynamic Numeric Environmental Modeling) software in Python, which enables the analysis of the formation of fold and fault structures, melt emplacement and contamination, as well as the duration and rate of geodynamic processes. GeoNEM is based on the computational geodynamics “marker-in-cell” (MIC) method, which treats geological media as extremely high-viscosity fluids. Locations of the brittle deformations of the crust, the formation of which was simulated numerically, can be detected through lineament analysis of remote sensing images. The spatial distribution of such structures—lineaments—serves as a predictive criterion for assessing the prospectivity of territories for Carlin-type gold deposits. It has been demonstrated that remote sensing provides a modern level of efficiency, cost-effectiveness, and comprehensiveness in approaching the exploration and assessment of new Carlin-type gold deposits. This is particularly important in the context of rational resource utilization and cost reduction. Full article

The water yield (WY) service is a critical ecosystem service in arid regions, and understanding its spatiotemporal heterogeneity and controls is important for sustainable watershed management. Annual water yield (WY) in the Aksu River Basin (ARB), China, from 2000 to 2020 was simulated using the InVEST model, with validation against observed runoff (NSE = 0.840, R² = 0.846, RMSE = 1.787). The results revealed a decline in WY from 66.49 mm in 2000 to 43.15 mm in 2015, while retaining a clear north–south gradient, with higher values in the north. Areas showing decreasing and increasing trends accounted for 45.34% and 3.14% of the basin, respectively. WY exhibited strong spatial autocorrelation (global Moran’s I = 0.912–0.941), with high-value clusters in the north and low-value clusters in the south. GeoDetector identified precipitation, temperature, and potential evapotranspiration as key drivers (q = 0.889, 0.880, and 0.832, respectively), with precipitation-related interactions generally exceeding 0.9, indicating enhanced explanatory power through multi-factor coupling. After variable screening and collinearity control, MGWR revealed spatially varying effects of drivers and significant spatial non-stationarity. Overall, despite the declining trend, WY in the ARB maintained a relatively stable spatial structure, with its heterogeneity primarily driven by the coupling of climatic forcing and topographic constraints, providing a scientific basis for zonal water resource management in arid river basins. Full article

Space Surveillance and Tracking (SST) plays a crucial role in ensuring space safety. To this end, accurate and numerous observational resources are needed to build and maintain a catalog of space objects. In particular, it is essential to develop optimal observation strategies to maximize both the number and the quality of detections obtained from a sensor network. This represents a key step in the assessment of the network through simulations. This work presents the integrated development of sensor tasking strategies for optical systems and a track-to-track correlation pipeline within S$\mathrm{\Xi }$NSIT, a software environment designed to simulate sensor network configurations and evaluate cataloging performance. For high-altitude low Earth orbit (HLEO) targets, which are fast-moving and widely distributed, tasking strategies emphasize systematic scans of the Earth’s shadow boundary to exploit favorable phase angles and improve observational accuracy, while medium- and geostationary-Earth orbits (MEO–GEO) rely on equatorial-plane scans. The correlation pipeline employs Two-Body Integrals, uncertainty propagation, and a ${\chi }^2$-test with the Squared Mahalanobis Distance to associate tracks and perform initial orbit determination of newly detected objects. Results indicate that the integrated approach significantly enhances detection coverage, leading to greater catalog build-up efficiency and improved SST performance. Consequently, it facilitates the cataloging of numerous uncataloged objects within a reduced timeframe. Full article

This paper presents a comprehensive study on the feasibility and implications of a CO₂ injection simulation in the Syderiai deep saline aquifer of Lithuania, focusing on leakage, geo-mechanical aspects, and geo-chemical aspects. The Syderiai aquifer, characterized by its sandstone formation covered by shaly rocks, is considered a potential site for CO₂ geological storage in Lithuania. Using 3D mechanistic models developed in T-navigator software, we conducted extensive simulations to analyze CO₂ storage behavior and associated impacts. The leakage study examines various scenarios to assess the impact of fracture permeability, layer-wise heterogeneity, and fracture position on CO₂ injection and leakage volumes. Results indicate that while fracture permeability influences CO₂ migration dynamics, its impact on both free and dissolved CO₂ leakage volumes is minimal, highlighting that leakage behavior is more dependent on the presence of fractures than their permeability. Geo-mechanical analysis reveals the effects of CO₂ injection on the bulk modulus and shear modulus of sandstone and shale formations, highlighting changes in compaction and cementation. The geo-chemical study was performed using TOUGHREACT software V4.13-OMP to investigate the distribution of pH, porosity change, and free CO₂ over 1000-years following 10-year CO₂ injection. Results demonstrate the acidifying effect of CO₂ injection and its implications for the caprock–reservoir interface over time. The findings offer valuable perspectives on the feasibility and consequences of CO₂ geological storage in the Syderiai deep saline aquifer, highlighting the importance of incorporating leakage, geo-mechanical aspects, and geo-chemical aspects for implementing efficient CO₂ storage. Full article

A central challenge in tight fault-depression reservoirs is understanding how three-dimensional fracture structures control gas storage and flow. This study introduces a data-driven, geologically informed framework that integrates structural-mechanical coupling to decipher fracture networks within the Shahezi Formation. Our model, based on rock failure criteria, achieves quantitative fracture prediction across one-dimensional to three-dimensional scales. This capability overcomes the limitations inherent in single-method approaches for tight, fracture-dominated reservoirs. By synthesizing sedimentary facies-controlled reservoir modeling, sweet-spot inversion, and geo-engineering integration, we establish a predictive system for accurate reservoir assessment. The continental clastic Shahezi Formation is typified by secondary fractures. This study utilizes leverage small-scale data (core, thin section, log) to quantify key parameters (fracture density, aperture), enabling a systematic analysis of fracture typology, heterogeneity, and controls. Building on this foundation, and spatially constrained by large-scale datasets (seismic interpretation, stress-field simulations), we developed a robust fracture development model for deep tight reservoirs. Stress-field modeling delineated fracture-prone zones, where a discrete fracture network (DFN) model was built to characterize 3D fracture geometry and connectivity. Integrating simulated fracture size and aperture-derived permeability allowed us to quantify fracture contribution to total permeability, ultimately mapping favorable targets. The results identify favorable zones primarily in the western sector of the study area, forming an NS-trending, belt-like distribution. They are mainly concentrated around the wells Changshen-4, Changshen-40, and Changshen-41. This distribution is clearly controlled by the Qianshenzijing Fault. Full article

In arid open-pit mines, rainfall-triggered slope instability presents significant risks, but quantitative thresholds are poorly defined due to limited integration of transient seepage and stability in low-permeability soils. This study fills this gap by using GeoStudio’s SEEP/W and SLOPE/W modules to simulate rainfall effects on a moderately steep-slope (51° average) limestone mine slope in Ningxia’s Kazimiao Mining Area (annual precipitation: 181.1 mm). The novelty lies in identifying a 12 h saturation window under intense rainfall (≥100 mm h⁻¹), during which pore water pressure stabilizes as soil reaches saturation, creating an “infiltration buffering effect” driven by arid soil properties (hydraulic conductivity: 2.12 × 10⁻⁴ cm s⁻¹). Results show that the factor of safety (FOS) drops sharply within 12 h (e.g., from 1.614 naturally to 1.010 at 200 mm h⁻¹) and then stabilizes, with FOS remaining >1.05 (basically stable) under rainfall intensities ≤ 50 mm h⁻¹, but drops into the less-stable range (1.00–1.05) at 100–200 mm h⁻¹, reaching marginal stability (FOS ≈ 0.98–1.02) after 24 h of extreme events, according to GB/T 32864-2016. Slope protection measures increase FOS (e.g., 2.518 naturally). These findings quantify higher instability thresholds in arid compared to humid regions, supporting regional guidelines and informing early-warning systems amid climate-related extremes. This framework enhances sustainable slope management for mines worldwide in arid–semi-arid zones. Full article

The large-scale development of mineral resources has led to a sharp increase in the amount of tailings and waste rock accumulated in tailings ponds and waste disposal sites, forming a large number of high-risk tailings dams and high-pile waste disposal sites. In recent years, frequent incidents of tailings dam breaches and landslides in high-pile dumping sites have posed a serious threat to the lives and property of downstream residential areas. Therefore, studying the collaborative storage technology of waste rock and tailings is of great significance. By conducting physical model experiments on tailings dams of a similar scale and using the SEEP/W module in GeoStudio 2022.1 software for numerical simulation, the influence of the built-in waste-rock inclusions on the permeability characteristics of the dam body and the depth of the saturation line is analyzed. The results showed that the seepage flow increased with the decrease in fine particle content in the waste-rock inclusions, with the highest seepage flow in the C-grade waste-rock inclusions and the most significant decrease in the saturation line, and the seepage volume decreased with the increase in the spacing between waste-rock inclusions. The depth of the saturation line is negatively correlated with the distance between the centers of the waste-rock inclusions; that is, the smaller the distance (200 mm), the greater the depth of the saturation line. The research results can provide a reference for ensuring the safety and stability analysis of tailings dams. Full article

Many cities worldwide face decline due to mineral-resource exhaustion, with mining-induced subsidence and land degradation posing urgent land use challenges. At the same time, carbon neutrality has become a global agenda, promoting ecological restoration, emissions reduction, and green transformation in resource-exhausted cities. However, empirical evidence on how carbon neutrality strategies drive land use transition remains scarce. Taking Xuzhou, China, as a case study, we integrate the GeoSOS–FLUS land use simulation model with a Markov chain model to project land use patterns in 2030 under three scenarios: natural development (ND), land recovery (LR), and carbon neutrality (CN). Using emission factors and a land use carbon inventory, we quantify spatial distributions and temporal shifts in carbon emission and sequestration. Results show that LR’s rigid recovery policies restrict broader transitions, while the CN scenario effectively reshapes land use by enhancing the competitiveness of low-carbon types such as forests and new-energy land. Under CN, built-up land expansion is curbed, forests and new-energy land are maximized, and emissions fall by 4.95% from 2020. Carbon neutrality offers opportunities for industrial renewal and ecological restoration in resource-exhausted cities, steering transformations toward approaches that balance ecological function and carbon benefits. Long-term monitoring is required to evaluate policy sustainability and effectiveness. Full article

Public health emergencies (PHEs) test the crisis response capacity of grassroots organizations like China’s Residential Committees (RCs). While existing research attributes this capacity to factors like resource mobilization or state-society relations, its deeper structural foundations in land regimes and spatial configurations remain underexplored, particularly in Global South urbanization contexts. To fill this gap, this study develops a “Grassroots Organizational Capacity” (GOC) analytical framework, which disaggregates capacity into four dimensions: information, implementation, mobilization and cooperation, and coercion. We then employ this framework in a comparative case study of urban (Jiayi) and rural (Hedong) neighbourhoods in Nanhai, China, during the 2022 lockdown. Drawing on semi-structured interviews with ten key stakeholders in 2022, the findings reveal divergent types of governance. In the rural case, collective land ownership and open spaces foster an “Embedded Autonomy” type, enabling a proactive response through dense social networks. In the urban case, state land dependency and spatial fragmentation lead to a “Reactive Co-Governance” type, which relies on top-down state intervention. This study’s contribution is to provide a case-based illustration of how land and space structures are actively associated with grassroots crisis response effectiveness, rather than serving as passive backdrops. Full article

In recent years, coal mining has shifted from surface to underground multi-seam and multi-panel operations, leading to enhanced ground deformation and elevated risks of secondary geo-hazards. However, the deformation mechanisms and spatiotemporal evolution of mining-induced ground movement in high-intensity repeated mining areas require further investigation. To gain further insight, this study focuses on elucidating the deformation mechanisms and hazard-chain evolution induced by downward multi-seam and multi-panel mining in the Hongyan coal mine, located in the loess gully region. An integrated InSAR-based multi-source monitoring and modeling framework was adopted, systematically combining InSAR, historical satellite imagery, UAV-based surveys, and ground observations with numerical simulations to characterize the spatiotemporal evolution of mining-induced deformation and examine the coupling processes within the hazard chain. The monitoring results show a strong spatiotemporal correlation between mining activities and ground deformation: subsidence basins and temporal variations correspond closely to the mining sequence, and the spatial distribution of fissures aligns with the advancing working faces. The analysis indicates mining-induced stress redistribution and stratum instability are the root causes of subsidence. Subsidence characteristics are affected by topography, mining sequence, and the cumulative impacts of multi-seam mining, leading to stepwise subsidence and subsidence basins. The overlying loess’s topography and characteristics affect the subsidence distribution. The “stress arch” formed in the goaf evolves with the multi-panel mining process, gradually collapsing during continuous mining and leading to stratum instability. Initially spreading stress and preventing rock movement, the upper residual pillars aggravate stratum damage following critical stratum failure. Mining exerts spatiotemporal control over hazard development, with the hazard chain evolving upward from the mining horizon, driven by fissure propagation and subsidence as the core processes, and reinforced by a bottom-up chain reaction and feedback among successive hazards. This study provides scientific insights for the planning and hazard prevention of multi-seam mining in loess gully regions. Full article

The geostationary orbit (GEO), a finite one-dimensional longitudinal resource, has emerged as a critical research focus driven by the rapid development of global communication systems. This scarcity motivates current research efforts toward multi-satellite collocation within single longitudinal slots. This article investigates the optimization design problem of configurations at fixed longitudes in GEO. First, a kinematic model describing the relative fixed-point motion of geostationary satellites was established. Subsequently, the long-term stability conditions of these fixed-point configurations under $J_2$ perturbations were analyzed, with collocation flight stability and passive flight safety formulated as design constraints. The particle swarm optimization (PSO) algorithm was employed to design circular and straight-line spatial configurations, and their corresponding Kepler orbital elements were numerically simulated. Comparative analysis confirmed that circular configurations demonstrate superior stability compared to straight-line configurations. Full article

The growing frequency of extreme weather, earthquakes, fires, and environmental hazards underscores the need for real-time monitoring and predictive management at the urban scale. Conventional three-dimensional spatial information systems, which rely on orthophotos and ground surveys, often suffer from computational inefficiency and data overload when processing large and heterogeneous datasets. To address these limitations, this study introduces a three-dimensional GeoHash-based geocoding algorithm designed for lightweight, real-time, and attribute-driven digital twin operations. The proposed method comprises five integrated steps: generation of 3D GeoHash grids using longitude, latitude, and altitude coordinates; integration with GIS-based urban 3D models; level optimization using the Shape Overlap Ratio (SOR) with a threshold of 0.90; representative object labeling through weighted volume ratios; and altitude correction using DEM interpolation. Validation using a testbed in Sillim-dong, Seoul (10.19 km²), demonstrated that the framework achieved approximately 9.8 times faster 3D modeling performance than conventional orthophoto-based methods, while maintaining complete object recognition accuracy. The results confirm that the 3D GeoHash framework provides a unified spatial key structure that enhances data interoperability across querying, visualization, and simulation. This approach offers a practical foundation for operational digital twins, supporting high-efficiency 3D mapping and predictive disaster management toward resilient and data-driven urban systems. Full article

Background/Objectives: Acute lung injury (ALI) is a severe condition driven largely by inflammation and has limited therapeutic options. Although saikosaponin B1 (SSB1), a primary bioactive saponin from Bupleurum Radix, has demonstrated anti-inflammatory properties, its efficacy against ALI and its corresponding molecular mechanisms remain largely unexplored. This study employed an integrated approach combining network pharmacology, transcriptomics, and metabolomics to decipher the protective mechanisms of SSB1 against ALI. Methods: Potential targets were identified via network pharmacology, and core targets were validated through molecular docking, dynamics simulations, and independent GEO transcriptomic datasets. Experimental validation was performed in an LPS-induced murine ALI model, combining histopathology, ELISA, and integrated transcriptomic and metabolomic analyses. Results: Integrated analyses identified IL1B, TNF, and IL6 as core targets through which SSB1 exerts its anti-ALI effects. These targets were validated by high-affinity binding in simulations, confirmed in independent GEO transcriptomic datasets, and shown to be normalized by SSB1 treatment in vivo. Mechanistically, SSB1 appears to modulate the NOD-like receptor and cGAS-STING signaling pathways and rectify the key metabolic pathways orchestrated by these targets, including glycerophospholipid, arachidonic acid, and linoleic acid metabolism. Conclusions: This study systematically investigates the therapeutic effects of SSB1 against ALI by identifying its potential targets and underlying pathways. These results provide crucial mechanistic insights and robust experimental support, thereby paving the way for the clinical translation of SSB1. Full article

With the increasing global burden of major depressive disorder (MDD), identifying modifiable environmental risk factors has become a critical priority. Per- and polyfluoroalkyl substances (PFASs), characterized by environmental persistence and bioaccumulation, have been linked to elevated mental health risks. However, the potential neurotoxicity of GenX—a novel PFAS developed to replace perfluorooctanoic acid (PFOA)—and its molecular association with MDD remain unclear. In this study, peripheral blood serum transcriptomic data from the Gene Expression Omnibus (GEO) were integrated with multidimensional bioinformatics analyses to elucidate molecular mechanisms connecting GenX exposure with MDD. Four hub genes (UCP2, AKR1B1, TP53, and F5) were identified, showing strong combined diagnostic performance (AUC = 0.925). Functional enrichment and immune infiltration analyses revealed their involvement in energy metabolism, oxidative stress, and immune-coagulation regulation. Molecular docking and dynamics simulations further confirmed stable interactions between GenX and these proteins, providing structural support for their mechanistic roles. Although classical dopaminergic markers (TH, SLC6A3, DRD1–5) were not detected in the serum-derived transcriptomes, the identified hub genes may still affect dopaminergic function indirectly by modulating metabolic, oxidative stress, and inflammatory/coagulation pathways, thereby influencing MDD susceptibility. This study provides the first integrated transcriptomic and structural evidence linking GenX to psychiatric risk, proposing a novel “GenX-dopamine-MDD” framework for understanding pollutant-mediated neuropsychiatric mechanisms. Full article