Search Results (844)

Groundwater-dependent communities such as De Aar require a better understanding of groundwater systems to ensure sustainable allocation. This study aims to trace recharge sources in unconfined and confined aquifers and identify processes controlling groundwater quality using hydrogeochemistry and environmental tracers. It argues that aquifer delineation and hydraulic parameters alone cannot fully identify recharge sources or geochemical processes; integrating them with hydrogeochemistry and environmental tracers provides stronger evidence to support groundwater allocation. To validate the argument, the study integrated hydrogeochemical analysis, stable isotopes, tritium, radon-222, and statistical methods supported by depth-specific groundwater sampling. The results, interpreted using Piper and Gibbs diagrams, PHREEQC modelling, and scatter plots, show that groundwater evolution is mainly controlled by rock–water interaction, ion exchange, evaporation, and mixing processes. Ca–HCO₃ water indicates recent recharge, while Na–Cl water reflects evaporation effects in both unconfined and confined aquifers, with halite dissolution contributing to Na and Cl enrichment. Isotope results indicate that unconfined aquifer water is isotopically enriched and linked to recent recharge, whereas confined aquifer and spring waters are depleted, suggesting recharge from higher elevations through fractured zones. Tritium dating reveals young (<30 years), intermediate (30–50 years), and old groundwater (60–109 years), while radon results indicate active groundwater flow path, particularly along fractures. These findings demonstrate that groundwater recharge is derived from both local meteoric sources and regional contributions, resulting in predominantly fresh groundwater; however, localized quality concerns should be considered for improved water allocation. Full article

Red mud discharged during alumina production via the Bayer process is characterized by high contents of sodium carbonate, sodium sulfate, and other soluble salts, and it remains poorly utilized and accumulates in long-term stockpiles. Sodium percarbonate has found extensive industrial applications, and its synthesis via the salting-out method represents one of the dominant industrial routes. In this context, sodium sulfate was employed as a salting-out agent. On the basis of relevant ternary systems, the phase equilibrium of the quaternary system Na₂CO₃–Na₂SO₄–H₂O₂–H₂O at 5 °C was systematically investigated and calculated. The objective was to utilize red mud as a waste resource and develop a novel integrated process that favored the wet synthesis of sodium percarbonate while enabling the efficient separation of sodium salts. The solubility data for the ternary subsystems constituting the above quaternary system were correlated using the Pitzer model, yielding the corresponding ion interaction parameters and activity coefficients. The validated model was then applied to predict the phase equilibrium data of the quaternary system. Verification results indicate that the calculated values are in satisfactory agreement with the experimental data. On the basis of the phase equilibrium data of the Na₂CO₃–Na₂SO₄–H₂O₂–H₂O system at 5 °C, a phase diagram was constructed. Along with five solid-phase crystallization fields, three invariant points were identified: the co-saturation point of Na₂SO₄·10H₂O, Na₂CO₃·10H₂O, and Na₂CO₃·1.5H₂O₂·H₂O; the co-saturation point of Na₂SO₄·10H₂O, Na₂CO₃·1.5H₂O₂·H₂O, and Na₂SO₄·0.5H₂O₂·H₂O; and the co-saturation point of Na₂CO₃·1.5H₂O₂·H₂O, Na₂SO₄·0.5H₂O₂·H₂O, and Na₂CO₃·2H₂O₂·H₂O. From phase diagram analysis, a novel wet process route for sodium percarbonate production using waste red mud is proposed. The process involves chemical reaction, crystallization, separation, and drying to obtain the final product. A new process flow diagram for the value-added production of sodium percarbonate is also presented. Full article

The lack of graph information caused by ignoring the association between learners often affects the accuracy of graph-based learning. This paper proposes an approach called attention-based multi-topological graph convolution (A-MTGCN) to address this. It uses a graph neural network to predict academic tasks. The method involves an attention mechanism that assigns weights to different academic characteristics to reflect their effects on prediction. Additionally, the topology between learners is constructed from multiple perspectives to capture potential interactions and collaboration, forming a weighted learner association diagram. This reduces redundancy and information dispersion in the graph, while retaining the correlation features. The approach divides learners into four types. Experiments show the enhanced GCN performs well in learner node classification, with an accuracy of 92.53%, precision of 89.15%, recall of 92.27%, and F1-score of 87.83%. The evolution process of learners’ learning state is reflected by constructing learners’ state transition matrix. Full article

Rapid urbanization has aggravated challenges in sustaining the peri-urban rice farming sector. Challenges arising from rapid urbanization threaten rice farmers in peri-urban areas because of increasing economic and land pressures. This has caused significant marginalization among rice farmers. In Indonesia, despite contributing 13.28% of the national gross domestic product (GDP) in 2021, the agricultural sector is dominated by marginal farmers who struggle with poverty and lack land ownership. This study aims to identify different pathways for the marginalization of rice farmers by integrating spatiotemporal land use and land cover (LULC) change analysis, landscape fragmentation metrics, and systems thinking (ST) through causal loop diagrams (CLDs). Furthermore, an attempt to reconceptualize the term marginal rice farmers is made by considering the total number of cultivated rice fields and broader factors that contribute to the feedback loop of marginalization. This study shows that rice farmer marginalization in peri-urban areas is caused by small land size or poverty, and the interactions between ecosystem service degradation, productivity decline, economic pressure, and land conversion differ across landscape configurations. Moreover, this study enhances the understanding of peri-urban agricultural transformation and provides landscape-sensitive policy insights to support inclusive and resilient agricultural systems by reconceptualizing the marginalization of rice farmers as a dynamic socio-spatial process. Full article

This study developed a microemulsion system based on diatomaceous earth (DE) for the topical delivery of resveratrol. The microemulsions were prepared using pseudo-ternary phase diagrams. A 4:1 ethanol:virgin coconut oil ratio resulted in a larger microemulsion region than a 3:1 ratio. Two formulations with oil (ethanol:virgin coconut oil, 3:1):Cremophor RH40:water ratios of 1:5:4 (ME1) and 2:5:3 (ME2) were selected for resveratrol loading and subsequently combined with DE at ratios of DE:microemulsion (DE:ME) 0.5:1, 0.5:2, and 0.5:3. The transmission electron microscopy images demonstrated the different microstructures of the microemulsions. Rheological analysis revealed an increase in storage modulus and a decrease in the linear viscoelastic region with increasing DE concentration, particularly in ME1. Differential scanning calorimetry showed disruption of boundary water following DE incorporation. Fourier-transform infrared spectroscopy indicated primarily physical interactions between resveratrol and the DE:ME system. DE:ME demonstrated high resveratrol content, approaching 100%. DE:ME1 0.5:2 significantly enhanced resveratrol permeation, resulting in a 3-fold increase compared with the microemulsion alone after 8 h. DE:ME1 0.5:2 and DE:ME2 0.5:3 enhanced the photostability of resveratrol and the formulations remained stable after storage at 40 °C for 6 months. The DE:ME system maintained its cellular uptake capability, preserved the biological activity of resveratrol, and exhibited low cytotoxicity in human keratinocytes, with cell viability remaining above 70%. These results highlight the potential of DE-based systems for incorporating microemulsions of low-water soluble photo-sensitizing substances in topical drug delivery applications. Full article

We introduce a minimal relational network model in which superconducting-like behavior emerges as a collective phase of constrained connectivity and phase coherence, without assuming microscopic electrons, phonons, or material-specific interactions. The model is formulated as a concrete instantiation of a previously introduced axiomatic relational–informational framework for emergent geometry and effective spacetime, in which geometry and effective forces arise from constrained information flow rather than from a background manifold. Mathematically, this construction is realized on a finite weighted graph with binary edge-activation variables and compact vertex phase variables, sampled through a Gibbs ensemble generated by an additive informational action. The system is represented as a finite weighted graph with weighted edges encoding transport or informational costs, augmented by dynamically activated low-cost channels and compact phase degrees of freedom defined at vertices. The effective edge costs induce a weighted shortest-path metric, providing an operational notion of emergent relational geometry. Using Monte Carlo simulations on two-dimensional periodic lattices, we show that the same informational action supports three distinct emergent regimes: a normal resistive phase, a fragile low-temperature–like superconducting phase characterized by noise-sensitive coherence, and a noise-robust high-temperature–like superconducting phase in which global phase coherence persists under substantial fluctuations. These regimes are identified using purely relational observables with direct graph-theoretic and statistical-mechanical interpretation, including percolation of low-cost channels, phase correlation functions, an operational phase stiffness (helicity modulus), and a geometric diagnostic based on relational ball growth. In particular, we extract an effective geometric dimension from the scaling of low-cost accessibility balls, using a ball-growth relation of the form $⟨B\left(r\right)⟩~r^{d_{eff}}$, revealing a clear monotonic hierarchy between normal, fragile superconducting, and noise-robust superconducting—like regimes. This demonstrates that superconducting-like behaviour in the present framework corresponds not only to percolation and phase alignment, but also to a qualitative reorganization of relational geometry. Robustness is tested via finite-size comparison between 8 × 8, 12 × 12 and 16 × 16 lattice realizations. Within this framework, normal and superconducting-like behavior arise from the same underlying relational mechanism and differ only in the structural stability of connectivity, coherence, and geometric accessibility under fluctuations. The aim of this work is structural rather than material-specific: we do not reproduce detailed experimental phase diagrams or microscopic pairing mechanisms, but identify minimal relational conditions under which low-dissipation, phase-coherent transport can emerge as a generic organizational regime of constrained relational systems. Full article

Coal and gas outbursts remain one of the most critical dynamic hazards in underground coal mining, driven by complex interactions among geological, gas-related, and structural factors. In this study, a dataset comprising 90 documented coal and gas outbursts occurred in Zonguldak Coal Basin was analyzed using the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method. Hierarchical levels of significance among key controlling factors were formed and the relative influence levels of the parameters were comparatively evaluated to determine their contribution to the outburst risk mechanism. The study focuses on prominence-based interpretation supported by total influence matrix heatmap rather than conventional cause–effect diagrams. The results indicate that the prominence index provides a clear hierarchy of factor importance reflecting a structurally symmetric interaction pattern among the selected variables. Mining depth, gas content, and moisture content together account for more than 70% of total system importance, identifying them as the dominant drivers of coal–gas outbursts. Fault distance shows a secondary influence, whereas seam thickness and inclination exhibit comparatively minor contributions. The results indicate that the interaction structure of outburst risk factors is balanced, and that risk is primarily governed by their combined influence. Therefore, prominence-based evaluation and heatmap visualization provide a more reliable and practical basis for identifying critical factors and prioritizing risk control strategies. The results provide practical guidance for risk prioritization and preventive planning in deep and gas-rich coal mines. Full article

Groundwater plays an indispensable role in daily life. However, with the continuous advancement of industrialization, more attention should be paid to the quality of groundwater and the associated potential health risks in areas surrounding industrial parks. In this study, groundwater samples collected in the city of the Tibetan Plateau during the wet season (WS) and dry season (DS) were analyzed using Piper diagrams, Gibbs diagrams, and correlation analysis. The results elucidated the hydrochemical characteristics, formation mechanisms, and controlling factors of groundwater in the area. Groundwater potability was assessed using the Entropy-weighted Water Quality Index (EWQI) method. In addition, the health risk assessment model was applied to evaluate potential risks for four population groups, with NO₃⁻ and F⁻ selected as representative groundwater pollutants. The findings revealed that groundwater in the study zone was typically moderately alkaline and characterized primarily as soft–fresh and hard–fresh. The groundwater in both seasons mainly exhibited HCO₃–Ca chemical facies. Water–rock interactions involving silicate and carbonate minerals were identified as key processes controlling the hydrochemical composition in both seasons. EWQI results showed that groundwater quality for drinking purposes was excellent in the seasons. Sensitivity analysis further showed that Cl− exerted the greatest influence on the drinking water quality evaluation in both seasons. Health risk assessments revealed that the risks posed by NO₃⁻ and F⁻ to infants, children, adult females, and adult males remained within acceptable limits (with max values of 0.63, 0.39, 0.28, and 0.33 in the WS, and 0.59, 0.36, 0.26, and 0.31 in the DS, respectively). However, infants exhibited greater susceptibility than the other groups across seasons, with a risk index approximately twice that of adults. Overall, the findings contribute valuable insights for the sustainable management and planning of groundwater resources in the study zone. Future research could refine the risk assessment model with localized data and explore mitigation strategies for elevated risks in specific seasons or regions. Full article

This study presents the first watershed-scale assessment of the impact of thermal spring discharges on the hydrochemistry and water quality of the Soummam basin (northeastern Algeria). Fourteen stations were monitored during three campaigns (October 2024, December 2024 and March 2025), combining physicochemical analyses, hydrochemical diagrams, and water quality indices (WQI and IWQI). The results reveal a clear spatial gradient in water composition, from low-mineral Ca-HCO₃/Ca-SO₄ facies in upstream areas to highly mineralized Na-Cl facies associated with thermal springs (Sidi Yahia and Sillal). Electrical conductivity reaches up to 27,359 µS/cm, reflecting intense mineralization driven by evaporite dissolution and deep water–rock interaction. This thermomineral signature propagates downstream through mixing and ion exchange processes, leading to progressive salinity enrichment. Water quality indices highlight significant degradation in thermally influenced zones, with approximately 50% of samples unsuitable for drinking (WQI > 300) and more than 60% classified as highly restricted for irrigation (IWQI < 40). Cluster analysis further confirms the distinction between severely impacted, moderately affected, and relatively preserved waters. Overall, the findings demonstrate that thermal discharges represent a major and persistent driver of salinization, emphasizing the need to incorporate geothermal influences into water resource management strategies in semi-arid environments. Full article

The hydrogeochemical characterization of shallow volcanic lakes at the Sete Cidades Volcano (São Miguel, Azores) provides new insights into the processes controlling water chemistry in low-depth lacustrine systems within active volcanic environments. Fourteen lakes (0.6–4 m deep) were sampled during two campaigns (winter 2024 and spring/summer 2025), combining in situ physicochemical measurements and major ion analyses along vertical profiles. The lakes are holomictic, cold (11.3–17.6 °C), slightly acidic (pH 5.66–5.95), and weakly mineralized (EC ~65–69 µS/cm), indicating dilute waters of predominantly meteoric origin. Hydrochemical facies are dominated by Na–Cl type, with strong correlations between chloride and conductivity (r = 0.857), supporting a major contribution from marine atmospheric deposition. To move beyond correlation-based interpretation, Gibbs diagrams and saturation indices (PHREEQC) were applied to constrain the dominant geochemical processes. Most samples plot within the precipitation dominance field, while all calculated saturation indices are negative (SI < 0), indicating undersaturation with respect to carbonate, evaporite, and silicate minerals. These results demonstrate that water chemistry is primarily controlled by atmospheric inputs, with only minor contributions from water–rock interaction and negligible influence of evaporation or mineral equilibrium processes. Seasonal increases in HCO₃⁻ and dissolved CO₂ at depth suggest enhanced organic matter decomposition during warmer periods, highlighting the role of biogeochemical processes in modulating carbon dynamics in shallow systems. The absence of a clear hydrothermal signature further distinguishes these lakes from deeper volcanic systems in the Azores. This study provides the first integrated hydrogeochemical framework for shallow volcanic lakes in the region, combining classical hydrochemistry with process-based tools. The results establish a quantitative baseline for assessing environmental change and improve the interpretation of external (atmospheric) versus internal (geochemical and biological) controls in volcanic lake systems. Full article

The behavior of Reinforced Concrete (RC) rectangular, slender columns is examined in this study upon exposure to heat-damage effects and fully confined by Carbon Fiber Reinforced Polymer (CFRP) wraps, where a new interaction diagram is proposed. The Nonlinear Finite Element Analysis (NLFEA) method is adopted to comprehensively understand the behavior of the RC columns, where a validation process takes place, followed by a wide parametric study. The studied parameters include the effect of different temperatures (23 °C (room temperature), 200 °C, 400 °C, 600 °C, and 800 °C) and nine eccentricity-to-height ratios where biaxial moments exist (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8). It has been found that the deformation, toughness, and the axial column’s strength are significantly improved by providing one layer of CFRP sheets for heat-damaged RC columns, while the stiffness behavior is only marginally affected. In addition, increasing the temperature reduces the energy absorption capacity and the ultimate strength of the columns while these are reduced by increasing the loading eccentricity value. However, columns experience a sudden and brittle failure when subjected to combined bending and axial loadings that might be accompanied by steel yielding or buckling of the column’s cross-section. Finally, the interaction diagram between the load and bending actions was constructed by addressing the results of the simulated columns. Full article

This study constructs an integrated analytical framework combining a Tripartite Coupling Coordination Degree Model (TCCDM), the Tapio decoupling model, and the Generalized Divisia Index Method (GDIM) to investigate the dynamic interactions and driving mechanisms among urban transportation, economic growth, and carbon emissions in Shanghai from 2000 to 2023. The results indicate that the coordination degree among the three systems evolves through three distinct phases: initial imbalance, critical transition, and high-level coordination. A three-dimensional phase diagram further reveals a marked shift from a “low-development, high-emission” pattern toward a balanced, high-quality development trajectory. Decoupling analysis demonstrates that economic growth and carbon emissions, as well as transport development and carbon emissions, have achieved significant decoupling in recent years. However, an expansive negative decoupling between economic growth and transportation highlights emerging challenges in sustaining synergistic development. Decomposition via GDIM shows that the interaction between economic development and transportation has consistently contributed to emission reduction, often exceeding the independent effects of either system. These findings underscore the role of systemic synergy in driving the nonlinear low-carbon transition of megacities. Consequently, policy interventions should adopt an integrated approach that fosters deep collaboration between green transportation transformation and high-quality economic development to effectively achieve carbon neutrality goals. Full article

Purpose: With the advent of sixth-generation (6G) communication technology, systematic mapping of its use cases to associated technical requirements has become essential for accelerating standardization, guiding R&D investment, and informing policy formulation. Methods: This study consolidated 65 use case scenarios from key academic and institutional 6G sources into 21 representative cases. A three-round Delphi-based expert assessment, employing a five-point Likert scale and interquartile-range-based consensus monitoring, was used to assign primary and secondary technical requirements across six core dimensions: immersive communication, massive communication, hyper-reliable low-latency communication, integrated sensing and communication, integrated artificial intelligence and communication (IAAC), and ubiquitous connectivity. A three-dimensional (3D) prism-based visualization framework was subsequently developed to represent the interdependencies among these requirements. Results: IAAC and massive communication emerged as the most critical requirements, each functioning as a primary or secondary driver across most use cases. The prism framework revealed hierarchical and complementary relationships among the six dimensions that conventional 2D wheel diagrams cannot adequately capture. Furthermore, a nine-criterion multidimensional classification framework, encompassing data transmission mode, decision-making mode, communication flow, interaction type, device type, deployment type, human activity innovation, user type, and personalization level, was developed, offering industry-specific guidance for service design. Collectively, the proposed framework supports user-centric design, informs strategic technology planning, and contributes to policy development while acknowledging existing limitations in quantitative mapping and economic analysis. Full article

The Beiyue Temple in Quyang County, Hebei Province, served as the host temple for worshipping the Northern Peak Deity (Beiyue shen) from its establishment during the reign of Emperor Xuanwu (483–515) of Northern Wei until the reign of Emperor Shunzhi (1638–1661) of the Qing dynasty. The temple currently houses over 200 inscribed stone steles that predate the founding of the Republic of China in 1912. This study addresses how the sacrificial space inside the Beiyue Temple evolved and transformed. By examining historical and archaeological evidence—including archival documents, epigraphic texts, diagrams, and architectural remnants—and focusing on the ‘front altar, rear garden’, the ‘hall for presenting sacrificial offerings of the common people’, and the ‘overhanging eave’, it demonstrates that the temple’s ritual space developed a dual character shaped by both official and folk practices. This duality reflects the interaction between official and folk practices against the backdrop of ‘the downward diffusion of ritual norms’ (lizhi xiayi) from the Tang and Song dynasties onwards. The findings challenge the conventional view that there was no specific space for folk ritual worship inside state-sanctioned temples during the Northern Song dynasty. It also provides vital evidence for the historical development of the sacrificial hall (xiandian) and the layout of pavilion-style stages (wuting) immediately in front of the main hall in temples built during the Song and Jin dynasties. Full article

Medical literature is replete with diagrammatic representations of systems, yet lacks standardised nomenclature and consistent symbolic conventions. In an introductory system dynamics course for health science students, causal loop diagrams (CLDs) are used to support systems thinking. Notwithstanding recognised limitations, CLDs provide a coherent heuristic for representing multivariate systems with feedback. We studied 55 first-year volunteers enrolled in the course to compare understanding of systems presented as CLDs versus typical journal diagrams. Two endocrine systems were selected from open-access, peer-reviewed literature: calcium homeostasis and glucose homeostasis. Participants were shown either the original journal diagram for one system and a CLD for the other, or vice versa, and answered twelve true/false questions—six per system. A mixed-model, two-way repeated measures ANOVA revealed a significant interaction between Diagram (CLD vs. journal diagram) and System (Calcium vs. Glucose). Post hoc comparisons showed significantly higher performance with CLDs for both Calcium (0.84 vs. 0.38) and Glucose (0.83 vs. 0.63), p < 0.001. A Fisher’s Exact Test also indicated a higher proportion of questions favouring CLDs. These findings suggest that training in CLDs may enhance understanding of complex systems compared to standard journal diagrams. Further work is needed to address limitations including the small sample size, use of a single cohort, and a restricted set of diagrams. Full article