Search Results (2,152)

Urban flood management is pivotal to the construction of resilient cities. However, investigation into the spatiotemporal evolution of urban flood resilience (UFR) and its influencing factors is insufficient. Aiming to address the challenge, this study establishes a multidimensional UFR indicator system grounded in the disaster resilience of place (DROP) model. Following the calculation of UFR through the entropy weighted technique for order preference by similarity to ideal solution (EW-TOPSIS) method, spatiotemporal evolution evaluation and factor detection are conducted. With panel data from the Yangtze River Delta Urban Agglomeration (YRDUA) over the period of 2012–2021, the results demonstrate overall UFR growth from a dominance of lowest-level and low-level cities to a more balanced distribution. Moreover, significant spatiotemporal heterogeneity is observed, with UFRs in cities adjacent to the Yangtze River higher than peripheral ones. Spatial clustering is significant until 2019, primarily manifested as High-High clusters along the Yangtze River and Low-Low clusters in northern Jiangsu and Anhui. Finally, factor detection identifies economic status, population size, environmental regulation, and drainage infrastructure as key influencing factors. These findings not only advance the understanding of UFR in urban agglomerations but also provide targeted recommendations for policymakers to enhance UFR. Full article

Background/Objectives: Pharmaceutical preparation technologies can enhance the bioavailability of poorly water-soluble drugs. Ursolic acid (UA) has been found to possess anti-cancer and hepatoprotective properties, demonstrating its potential as a therapeutic agent; however, its hydrophobicity and low solubility present challenges in the development of drug formulations. This study investigates the preparation of a nano-UA suspension by wet grinding, researches the influence of process parameters on particle size, and explores the rules of particle breakage and agglomeration by combining model fitting. Methods: Wet grinding experiments were conducted using a laboratory-scale grinding machine. The particle size distributions (PSDs) of UA suspensions under different grinding conditions were measured using a laser particle size analyzer. A single-factor experimental design was employed to optimize operational conditions. Model parameters for a population balance model considering both breakage and agglomeration were determined by an evolutionary algorithm optimization method. By measuring the degree to which UA inhibits the colorimetric reaction between salicylic acid and hydroxyl radicals, its antioxidant capacity in scavenging hydroxyl radicals was indirectly evaluated. Results: Wet grinding process conditions for nano-UA particles were established, yielding a UA suspension with a D50 particle size of 122 nm. The scavenging rate of the final grinding product was improved to three times higher than that of the UA raw material (D50 = 14.2 μm). Conclusions: Preparing nano-UA suspensions via wet grinding technology can significantly enhance their antioxidant properties. Model regression analysis of PSD data reveals that increasing the grinding mill’s stirring speed leads to more uniform particle size distribution, indicating that grinding speed (power) is a critical factor in producing nanosuspensions. Full article

Rapid climate change has exacerbated global ecosystem degradation, leading to habitat fragmentation and landscape connectivity loss. Constructing ecological networks (EN) with resilient conduction functions and conservation priorities is crucial for maintaining regional ecological security and promoting sustainable development. However, the spatiotemporal modeling and dynamic resilience assessment of EN under the combined impacts of future climate and land use/land cover (LULC) changes remain underexplored. This study focuses on the Central Yunnan Urban Agglomeration (CYUA), China, and integrates landscape ecology with complex network theory to develop a dynamic resilience assessment framework that incorporates multi-scenario LULC projections, multi-temporal EN construction, and node-link disturbance simulations. Under the Shared Socioeconomic Pathways and Representative Concentration Pathways (SSP-RCP) scenarios, we quantified spatiotemporal variations in EN resilience and identified resilience-based conservation priority areas. The results show that: (1) Future EN patterns exhibit a westward clustering trend, with expanding habitat areas and enhanced connectivity. (2) From 2000 to 2040, EN resilience remains generally stable, but diverges significantly across scenarios—showing steady increases under SSP1-2.6 and SSP5-8.5, while slightly declining under SSP2-4.5. (3) Approximately 20% of nodes and 40% of links are identified as critical components for maintaining structural-functional resilience, and are projected to form conservation priority patterns characterized by larger habitat areas and more compact connectivity under future scenarios. The multi-scenario analysis provides differentiated strategies for EN planning and ecological conservation. This framework offers adaptive and resilient solutions for regional ecosystem management under climate change. Full article

The aim of this work was to investigate the evolutionary mechanisms of an artificial sedimentary agglomerate formed by cathodic polarization in natural seawater during its abandonment to a natural environment. Previous studies indicate that the mineralogical evolution of the material is controlled by kinetic factors and/or the local precipitation of aragonite on the brucite surface. However, the observation of the precipitation of metastable phase precipitation during the initial immersion of this material (in powder form) has suggested the possibility of a more complex mechanism. The present study builds upon previous experimental work and includes thermogravimetric analysis and infrared spectrometry. The results are analyzed using numerical experimentation to evaluate the proposed hypotheses. Findings show that the transformation mechanism is characterized by the precipitation of metastable calcium carbonate phases. Under supersaturation conditions, these hydrated phases form on the brucite surface, limiting the mineral’s contact with the solution. The subsequent transformation of these amorphous phases into aragonite further reduces brucite–solution interaction, which explains the persistence of brucite both in the residual powder after 120 h of immersion and in the consolidated material after more than 20 years of exposure to natural seawater. Full article

Hydrogen has been explored as a greener alternative for greenhouse gas emissions reduction. Sodium borohydride (NaBH₄) is a favorable hydrogen carrier due to its high hydrogen content, safe handling, and rapid hydrogen release. This work presents a novel synthesis of the catalyst CoFe₂O₄/Fe₂O₃ using nanocellulose fibers (TCNF) as reactive templates for metal adsorption and subsequent calcination. The resulting material was tested for H₂ production from basic NaBH₄ aqueous solutions (10–55 °C). The catalyst’s composition is 74.8 wt% CoFe₂O₄, 25 wt% Fe₂O₃, and 0.2 wt% Fe₂(SO₄)₃ with agglomerated spheroidal particles (15–20 nm) and homogeneous Fe and Co distribution. The catalyst produced 1785 mL of H₂ in 15 min at 25 °C (50 mg catalyst, 4.0% NaBH₄, and 2.5 wt% NaOH), close to the stoichiometric maximum (2086 mL). The maximum H₂ generation rate (HGR) reached 3.55 L min⁻¹ g_cat⁻¹ at 40 °C. Activation energies were determined using empirical (38.4 ± 5.3 kJ mol⁻¹) and Langmuir–Hinshelwood (L–H) models (42.2 ± 5.8 kJ mol⁻¹), consistent with values for other Co-ferrite catalysts. Kinetic data fitted better to the L–H model, suggesting that boron complex adsorption precedes H₂ evolution. Full article

Recently, cross-city recreation has received a considerable amount of attention to meet the challenges of today’s rapid urbanization, the limited green space in cities, and the increasing demand for urban residents to interact with natural environments. We use China’s Capital Economic Circle as a case study to examine the influence of cross-city recreation on park green space accessibility. Using a Normalized Difference Vegetation Index and an Multi-mode two-step floating catchment area (M2SFCA) model, different travel modes across the space were explored. The results show the following: (1) The landscape of multi-scale Park green space (PGS) accessibility in the study area exhibits a gradual decrease in accessibility from the core area to the periphery. (2) Cross-city recreation changes the spatial distribution of accessibility, with the emergence of hotspots having the greatest impact on PGS accessibility at the scale of 50–100 ha and above. (3) At the urban scale, the multi-scale PGS of peripheral urban areas is higher than central urban areas, and affected by cross-city recreation, this feature is more significant in urban core areas. Our research helps urban planners to develop effective regional environmental planning policies for the green development of urban agglomerations. Full article

Background/Objectives: Crystallization is a key process in the manufacturing of active pharmaceutical ingredients (APIs), as it significantly affects the physical and chemical properties of the final product. Nicergoline, a clinically relevant ergot derivative, was chosen as a model compound to investigate how different crystallization strategies affect particle attributes. The objective of this study was to compare controlled and uncontrolled crystallization techniques and evaluate their impact on the physicochemical properties of nicergoline. Methods: Nicergoline was crystallized using controlled methods, including sonication-induced and seeding-induced crystallization, and uncontrolled methods, namely cubic and linear cooling, as well as acetone evaporation. The resulting powders were characterized by using a range of physicochemical techniques to assess particle morphology, size distribution, agglomeration behavior, and surface properties. Results: Uncontrolled crystallization methods produced particles prone to agglomeration, resulting in a broader particle size distribution ranging from 8 to 720 µm and heterogeneous surface characteristics. In contrast, controlled crystallization generated more uniform particles with reduced agglomeration and narrower particle size distributions. Among the evaluated methods, sonocrystallization provided the most effective control over particle size and morphology, demonstrated by a narrow size distribution ranging from 16 to 39 µm which correlated with improved flowability and surface energy. Conclusions: The study demonstrates that the choice of crystallization method significantly influences the structural and physicochemical properties of nicergoline. These findings highlight the importance of method selection for tailoring API properties to enhance downstream processing and product quality. Full article

Wet agglomeration is essential in heap leaching of minerals, as it improves permeability by forming agglomerates through capillary and viscous forces. The Discrete Element Method (DEM) has been used to model this phenomenon, enabling the detailed tracking of interactions between individual particles. This study employs DEM to analyze the effect of particle-size distribution (PSD) on agglomerate formation inside a rotating agglomeration drum. The DEM model was validated using geometry and parameters reported in the literature, which are based on experimental studies of agglomeration in rotating drums. Both wide and bimodal PSD cases were simulated. The results demonstrate that DEM simulations of drums with exclusively fine particles are prone to producing poorly defined macrostructures. In contrast, the presence of coarse particles promotes the formation of stable agglomerates with fine particles attached to them. Additionally, decreasing the maximum particle size increases the number of agglomerates and improves the homogeneity of the final PSD. These findings improve our understanding of wet agglomeration dynamics and provide practical criteria for optimizing feed design in mineral-processing applications. Full article

China’s rural revitalization strategy has entered a new stage of development, in which optimizing the layout of rural settlements constitutes both a critical component and an urgent task for promoting integrated urban–rural development. Important ecological function areas play a vital role in maintaining ecological security; however, research focusing on the evaluation and optimization of rural settlement suitability within these regions remains limited, thereby constraining their sustainable development. Accordingly, this paper selects Shiyan City, situated within the core water source area of China’s South-to-North Water Diversion Project, as a case study. From an ecological perspective, a suitability evaluation system for rural settlements is developed, specifically tailored to important ecological function areas. This system integrates ecological factors including geological hazards, vegetation coverage, soil and water conservation, and soil erosion. Utilizing GIS spatial analysis and the minimum cumulative resistance model, the study assesses the suitability of rural settlements within these important ecological function areas. Furthermore, it proposes corresponding optimization types and strategies for rural settlements in such areas. The findings indicate the following: (1) The rural settlements in the study area demonstrate a “large dispersed settlements and small clustered settlements” distribution pattern, exhibiting an overall high-density agglomeration, though their internal layout remains fragmented and disordered due to geographical and ecological constraints. (2) The spatial comprehensive resistance values in the study area exhibit significant heterogeneity, with a general pattern of lower values in the north and higher values in the south. The region was categorized into five suitability levels: high yield, highly suitable, generally suitable, less suitable and unsuitable. The highly suitable areas, despite their limited spatial extent, support the highest density of rural settlements. In contrast, unsuitable areas occupy a substantially larger proportion of the territory, reaching 46.83%. These areas are strongly constrained by topographic and ecological factors, limiting their potential for development, and the spatial layout of villages requires further optimization, with emphasis placed on ecological conservation and adaptive sustainability. (3) Rural settlements are categorized into four optimized types: Urban–rural integration settlements, primarily located in high yield areas, are incorporated into urban development plans after optimization. Adjusted and improved settlements, mainly in highly suitable areas, enhance service quality and stimulate economic vitality post-optimization. Relocation and renovation settlements, including those in generally suitable and less suitable areas, achieve concentrated living and improved ecological livability after optimization. Restricted development settlements, predominantly in unsuitable areas, focus on ecological conservation and regional ecological security post-optimization. This study integrates ecological function protection factors with spatial optimization zoning for rural settlements in the study area, providing scientific reference for enhancing residential safety and ecological security for rural residents in important ecological function areas. Full article

Given that the increasing non-agricultural conversion of cultivated land (NACCL) endangers food security, studying the spatial and temporal variation characteristics and driving mechanisms of NACCL in Sichuan Province can offer a scientific foundation for developing local farmland preservation measures and controlling further conversion. Guided by the theoretical framework of land use transition, this study utilizes land use datasets spanning multiple periods between 2000 and 2023. Comprehensively considering population scale factors, natural geographical factors, and socioeconomic factors, the county-level annual NACCL rate is calculated. Following this, the dynamic evolution and underlying driving forces of NACCL across 183 counties in Sichuan Province are examined through temporal and spatial dimensions, utilizing analytical tools including Nonparametric Kernel Density Estimation (KDE) and the Geographical Detector model with Optimal Parameters (OPGD). The study finds that: (1) Overall, NACCL in Sichuan Province exhibits phased temporal fluctuations characterized by “expansion—contraction—re-expansion—strict control,” with cultivated land mainly being converted into urban land, and the differences among counties gradually narrowing. (2) In Sichuan Province, the spatial configuration of NACCL is characterized by the expansion of high-value agglomerations alongside the dispersed and stable distribution of low-value areas. (3) Analysis through the OPGD model indicates that urban construction land dominates the NACCL process in Sichuan Province, and the driving dimension evolves from single to synergistic. The findings of this study offer a systematic examination of the spatiotemporal evolution and underlying drivers of NACCL in Sichuan Province. This analysis provides a scientific basis for formulating region-specific farmland protection policies and supports the optimization of territorial spatial planning systems. The results hold significant practical relevance for promoting the sustainable use of cultivated land resources. Full article

The viscous rheological behavior of suspensions of mixtures of fumed silica nanoparticles (N20) and rod-shaped cellulose nanocrystals (NCC) were studied experimentally. The fumed silica concentration varied from 2 to 11.3 wt% and the NCC concentration varied from 0.99 to 6.73 wt%. The suspensions of pure fumed silica, pure NCC, and mixtures of N20 and NCC were non-Newtonian shear-thinning in nature. The viscosity versus shear rate data of all suspensions of pure and mixed additives could be described satisfactorily by a power-law model. The consistency and flow behavior indices of the suspensions were strongly dependent on the concentrations of both N20 and NCC. While the consistency index increased sharply with the increases in additive (N20 and NCC) concentrations, the flow behavior index generally decreased with the increases in N20 and NCC concentrations. Thus, the suspensions became more shear-thinning with the increases in N20 and NCC concentrations. The shear-thinning of suspensions was due to two different mechanisms: the orientation of rod-shaped cellulose nanocrystals in the flow direction with the increase in shear rate and the break-up of large agglomerates of fumed silica aggregates with the increase in shear rate. Full article

In the context of the digital economy reshaping the global competitive landscape, digital industry clusters have become the key driving force to overcome the diminishing returns of traditional inputs and realize sustainable economic development in the digital era. However, the internal mechanisms and spatial effects through which digital industrial clusters drive high-quality development and thereby foster sustainable regional economic growth remain unclear. Based on China’s provincial panel data from 2012 to 2023, this study constructs time-fixed spatial Durbin model and mediation effect model to systematically examine the impact mechanism of digital industry clusters on high-quality economic development, and to analyze their direct effects, spatial spillover effects and mediation transmission effects. The following effects have been found: (1) digital industry clusters can directly promote the high-quality development of the region’s economy (0.070), and can also significantly promote the high-quality development of the region’s economy through the mediating effect of innovative talent agglomeration (0.021); (2) the spatial spillover effect of digital industry clusters consists of the negative siphoning effect of innovative talent and positive technology diffusion and driving effect, which makes the total effect of digital industry clusters on neighboring regions uncertain; (3) Technology-intensive areas, as well as the eastern and northeastern regions, have effectively transformed the advantages of digital industry clusters into momentum for high-quality economic development, whereas central and western regions have not yet fully unleashed the driving effect of digital industry on the high-quality development of the economy, due to the constraints of the industrial structure, innovation factors and infrastructure. Based on the empirical results, the article suggests accelerating the construction of digital industry innovation hubs, establishing cross-regional technology sharing platforms, constructing a negative externality compensation mechanism for talent loss areas, and implementing differentiated regional development strategies. The study addresses a gap in existing research by analyzing the spatial mediation effects of digital industrial agglomeration on high-quality economic development. It extends theoretical insights into industrial clustering within the digital economy and offers actionable policy pathways for developing countries to promote sustainable economic growth through digital industrial clusters. Full article

Carbon emissions in the building materialization stage are highly significant and concentrated. Quantification at this stage is essential for assessing carbon reduction potential, guiding energy-saving strategies, and supporting China’s “dual carbon” goals in the construction sector. Distinct from conventional environmental and energy economics analytical approaches, the building carbon emissions in the materialization stage (BCEMS) in 30 provinces of China from 2010 to 2021 were calculated using multi-source data, and the characteristics of their spatio-temporal evolution were analyzed. The key influencing factors were identified using a geographic detector, and their spatial heterogeneity was analyzed with the Geographically and Temporally Weighted Regression (GTWR) model from a geographical analysis perspective. The results indicated the following: (1) From 2010 to 2021, BCEMS exhibited a trend of an “initial increase followed by a decrease and subsequent fluctuation”, with an average annual growth rate of 4.28%. Building materials were the largest contributor to BCEMS, particularly cement and steel. Spatially, the emissions displayed a pattern of “higher in the east, lower in the west”. High–high-agglomeration areas remained stable over time, primarily in Zhejiang and Fujian provinces, while low–low-agglomeration areas were concentrated in Xinjiang. (2) Single-factor detection revealed that fixed assets, population density, and the liabilities of construction enterprises were the dominant factors driving the emissions’ spatial evolution. Two-factor interaction detection identified the economic society and the construction industry as the key influencing domains. (3) The economic development level and the total population showed a positive correlation with BCEMS, with the effect intensity increasing from west to east. The urbanization level and fixed assets also generally showed a positive correlation with BCEMS; however, their effect intensity initially increased positively from west to east and then turned into a negative enhancement. The findings provide references for implementing regionally differentiated carbon reduction measures and promoting green and low-carbon urban transformation in China’s construction industry. Full article

The supply–demand network facilitates regional sustainable development by optimizing resource flows and allocation within the Water–Energy–Food system. However, few studies have constructed such networks from a Water–Energy–Food Nexus (WEF Nexus) supply–demand perspective, and the key driving factors influencing network formation, along with their underlying mechanisms, remain poorly understood. To bridge this gap, we propose a new framework for constructing WEF Nexus supply–demand networks via explainable artificial intelligence (EAI). Taking the Bohai Rim urban agglomeration as an example, we identified the key factors affecting the long-term supply and demand of the WEF Nexus and their mechanisms using the XGBoost-SHAP model. By quantifying the magnitude and direction of these factors’ influences, we constructed supply–demand networks and further developed optimization strategies that consider complex factor interactions and distinct thresholds. Key findings include: (1) Identification of 114 stable supply sources and 128 chronic deficit sources, forming 472 high-efficiency and 296 standard supply–demand corridors, with 6 major supply potential zones delineated. (2) Precipitation, vegetation coverage, human activity intensity, cropland distribution, and temperature emerged as primary determinants in descending order of importance. (3) Synergistic analysis revealed significant negative interactions between human activity and precipitation/vegetation, but positive correlation with temperature, with distinct nonlinear thresholds across zones. Based on these findings, we proposed a differentiated optimization strategy. Our study constructs a supply–demand network from the perspective of the WEF Nexus and highlights the importance of threshold effects and interactions among key factors in the construction and optimization of the network. The research results are also applicable to other urban agglomerations facing similar challenges. Full article

Amid demographic restructuring, analyzing the dynamic interplay between public services and population development is vital for advancing coordinated regional development in the Beijing–Tianjin–Hebei Urban Agglomeration (BTHUA). This study developed an integrated evaluation framework, applying relative development indices, coupling coordination models, and obstacle analysis to examine the spatiotemporal evolution, coordination dynamics, and key constraints of the public service system and population system development from 2012 to 2023. The findings reveal the following: (1) Coordinated development policies have significantly boosted public service levels in cities near Beijing, whereas growth in Beijing and Tianjin has slowed. (2) Although overall coupling coordination across the BTHUA has improved, a marked core–periphery disparity persists. Beijing maintains high-level coordination, while most Hebei cities remain at marginal coordination levels. (3) The constraints on coordinated development vary substantially: Beijing primarily encounters structural challenges in population dynamics, whereas Tianjin and Hebei face basic infrastructural deficiencies. The study recommends developing a public service delivery system aligned with evolving demographic trends and proposes targeted strategies to optimize regional service structures based on each city’s core challenges. Full article