Search Results (4,490)

The synergistic utilization of post-mining spaces and geothermal energy through underground seasonal thermal energy storage (USTES) provides a promising pathway for sustainable heating and the low-carbon redevelopment of mining regions. To advance the thermal management and reveal the thermo-hydraulic evolution patterns within these repurposed environments, this study proposes an integrated approach that utilizes post-mining roadways as heat storage reservoirs, within the scope of a single idealized case study. A comprehensive USTES heating system model was established to systematically evaluate operational characteristics and environmental impacts under diverse conditions assuming homogeneous rock properties and idealized thermal boundaries. Results demonstrate that the surrounding ground temperature and the low thermal conductivity of the rock mass contribute to limiting heat dissipation and maintaining stable seasonal storage performance. For a roadway with a 20,000 m³ water storage capacity and an optimal 3900 m² solar collector area, the system successfully satisfies the thermal demand of 30,000 m² of building area. The configuration achieves 1239 MWh of cumulative heat storage over a 245-day cycle, maintaining a direct heating-to-heat-pump-upgraded heating ratio of 1.02. Furthermore, the implementation of variable-frequency thermal management strategies demonstrates remarkable economic and environmental superiority, yielding a 35.8% cost reduction compared to coal-fired heating, an overall energy saving rate of 77.5% relative to electric heating systems and a 13.5% decrease in CO₂ emissions relative to gas-fired systems. This research provides fundamental design parameters for the synergistic exploitation of mineral and geothermal resources, advancing the development of green heating and the sustainable utilization of post-mining spaces. Full article

The high-rate biological contactor (HRBC) is an enhanced-primary, biosorption-based, carbon-diversion wastewater treatment process with short hydraulic retention time (HRT), short solids retention time (SRT), low dissolved oxygen (DO), and high food-to-microorganism ratio (F/M). This paper presents modifications to a commercial full-plant wastewater biodegradation model using extracellular polymeric substances (EPS) in waste activated sludge (WAS) to simulate pilot test biosorption data. Bench-scale HRBC tests found that each mg of EPS as COD (COD_EPS) biosorbed 1.02 mg sCOD contained in raw wastewater. The fraction of AS organics identified as EPS in terms of COD was 37% in a conventional AS (CAS), 33% in a trickling filter-solids contact (TF/SC), and 18% in a membrane bioreactor (MBR). The modeling process used stoichiometry equations to convert EPS from its constituent concentrations (carbohydrates, proteins, humic acids, uronic acids) into COD. The conversion did not alter the finding that the normalized total EPS showed a positive relationship with soluble chemical oxygen demand sCOD biosorption with a 0.91 coefficient of determination. The modified commercial biodegradation model gave a maximum error of −12.6% when simulating pilot-scale results, and 80% of all data points were less than ±10% error. The modified model predicted 16% sCOD biosorption by EPS using the design data for a full-scale HRBC facility currently under construction. Full article

Tailings remediation alleviates ecosystem degradation and protects species. To conserve terrestrial biodiversity and address sustainability challenges while achieving economic growth, numerous researchers have devoted efforts to monitoring ecological functions and optimizing community structures. This study investigates the microbial characteristics and functional diversity across ecological succession stages of tailings. Selecting three typical restoration stages, including biological crust, moss, and grassland stages, we adopt 16S rRNA and ITS gene amplification, Illumina high-throughput sequencing, spectroscopy, and network correlation analysis to explore the responses of soil multifunctionality index, microbial communities, and carbon metabolism during tailings restoration. The experimental results indicate that the functional diversity index increases with ecological succession and is significantly correlated with the bacterial genera Rubrobacter and Arenimicrobium, whereas no significant correlation is observed with dominant fungi. The network interactions among bacterial communities are gradually strengthened along the succession process. In terms of carbon metabolic functions, the relative abundances of galactose, starch, and sucrose metabolism pathways increase obviously with restoration progression, while inositol phosphate metabolism, peroxisome metabolism, retinol metabolism, glyoxylate and dicarboxylate metabolism, and xenobiotics metabolism exhibit no significant variations. These findings provide novel empirical evidence for explaining microbe-mediated ecological succession in tailing ecosystems and highlight the necessity of multi-perspective analysis for ecological restoration. Policy and practical implications emphasize that the application of specific microorganisms and their interspecific interactions to promote iron tailings ecological restoration should fully consider the spatiotemporal heterogeneity of tailings areas. This study deepens the understanding of differential microbial responses at different tailings restoration stages and provides actionable insights for balancing mining economic development and terrestrial ecosystem conservation. Full article

Islanded renewable microgrids must balance power internally, so day-ahead dispatch is affected by wind and photovoltaic variability, battery state-of-charge (SOC) dynamics, demand-response (DR) participation, and emissions from dispatchable generation. This paper proposes a low-carbon economic dispatch model for an islanded photovoltaic–wind-turbine–battery-energy-storage–dispatchable-generator–demand-response (PV-WT-BESS-DG-DR) microgrid. The objective includes fuel, operation and maintenance, BESS degradation, renewable curtailment, load shedding, DR compensation, and carbon-emission costs. A repair-based constraint-handling strategy keeps the search space continuous while enforcing power balance, DG ramping, BESS operating and SOC limits, terminal SOC, and DR constraints. An improved whale optimization algorithm (WOA) is then developed with three modules: diversity enhancement, exploration–exploitation balancing, and local escape and refinement. The method is assessed through base-case dispatch, benchmark comparison, strategy comparison, ablation tests, and sensitivity analysis. In 30 independent runs, the proposed method achieves a mean cost of 2662.96 CNY/day, 4.07% lower than standard WOA, and reduces the standard deviation by 79.72%. Wilcoxon and Friedman tests confirm significant differences from the benchmark algorithms. Sensitivity tests show that higher BESS degradation coefficients and carbon prices increase the accounting cost but do not change the qualitative feasibility of the deterministic dispatch framework. Full article

With the global advancement of carbon peaking and carbon neutrality goals, the importance of carbon capture, utilization, and storage (CCUS) technologies has become increasingly prominent. As a critical component of CCUS systems, gaseous CO₂ pipeline transportation has emerged as a research hotspot due to its efficiency and cost effectiveness. However, there are invariably corrosion problems when it comes to gaseous CO₂ pipeline transportation. These issues pose a significant threat to both the safety and economic viability of pipeline operations. Therefore, it is of importance to investigate gaseous CO₂ corrosion during pipeline transportation. In this work, based on recent domestic and international research achievements, research progress in the field of gaseous CO₂ corrosion during pipeline transportation is systematically reviewed. First, the corrosion mechanisms and corrosion characteristics during gaseous CO₂ pipeline transportation are studied, and the synergistic mechanisms by which key parameters such as impurities, temperature, pressure, flow velocity, and water content jointly influence pipeline wall corrosion behavior are elucidated. Then, corrosion products in CO₂ transportation pipelines are analyzed, and protective measures applicable to gaseous CO₂ pipeline systems are synthesized. Finally, future research goals are proposed to promote research on gaseous CO₂ corrosion during pipeline transportation: the impact of interactions among multiple impurities on corrosion behavior should be clarified; the inhibitory effects of the dynamic evolution of product films on mass transfer processes should be considered in corrosion rate calculation models; and more economical and efficient anti-corrosion technologies should be developed to meet diverse operational requirements. This work can provide guidance for the corrosion protection of gaseous CO₂ pipeline transportation. Full article

Alpine grasslands and alpine deserts represent two major ecosystems on the Tibetan Plateau. However, whether the two ecosystems differ in soil microbial community diversity and co-occurrence network structure remains poorly understood. This study assessed the composition and diversity of soil bacterial communities across alpine grasslands and alpine deserts on the Tibetan Plateau via 16S high-throughput sequencing, analysis of variance(ANOVA), mantel test, and other methods. Our results revealed that soil alkaline-hydrolyzable nitrogen (SAN), soil total nitrogen (STN), soil total phosphorus (STP), soil available phosphorus (SAP), and soil organic carbon (SOC) were significantly higher in grassland than in desert (p < 0.05). The microbial community composition and diversity differed significantly between alpine grasslands and alpine deserts. Analysis of microbial co-occurrence networks revealed that grassland systems possessed significantly more nodes, edges, and a higher average degree than desert systems, along with greater network robustness—indicating a more complex and stable microbial community structure. Correlation analysis further revealed that SOC and STN were positively correlated with microbial diversity, while electrical conductivity (EC), SOC, STN, and SAN showed positive associations with microbial community composition. In conclusion, alpine grasslands harbor greater soil microbial diversity and more stable microbial co-occurrence networks than alpine deserts, suggesting that alpine grasslands may hold greater ecological value than alpine deserts in maintaining soil biodiversity and ecosystem functioning. This study not only elucidates the distribution patterns and diversity of soil microbial communities across Tibetan grasslands, but also offers critical insights into the mechanisms governing ecosystem functioning, thereby informing ecological conservation and sustainable management strategies on the plateau. Full article

Rivers have always been essential to humankind. They are used for many purposes and, as a result, have been heavily modified. Human impacts, many of them still poorly understood, interfere with river ecosystems, making them vulnerable to disturbances. Amongst these, mega events along riverbanks are listed. We studied the effects of the “FM4 Frequency Festival,” which attracted more than 200,000 visitors, on microalgae in the channelized section of the River Traisen in St. Pölten, the capital of Lower Austria. During the festival, phosphorus, dissolved organic carbon, and chloride increased significantly during the whole study period compared with before and after. Although the overall epilithic biomass remained unchanged during the festival period, the phytobenthos community experienced an increase in taxonomic richness downstream of the festival area. Both the Shannon diversity (mean ± SD = 2.89 ± 0.34) and Pielou’s evenness (mean ± SD = 0.73 ± 0.08) did not differ significantly between the sampling dates before, during, and after the festival. We found a shift towards Achnanthidium minutissimum as the dominant species during the festival. Diatoma ehrenbergii, which is sensitive to nutrient enrichment and organic pollution, disappeared during the event. Overall, the biofilm shifted towards a community dominated by heterotrophs during the festival, likely due to high organic loading. Pelagic microalgae experienced a rise in the total taxa number during the festival, which was partly caused by resuspension of phytobenthos. Our results reflect significant impacts from visitors to the Traisen ecosystem. Not only short-term changes in the hydrochemical environment but also mechanical disturbances of the phytobenthos caused by visitors were demonstrated. We suggest continuous monitoring to verify that such events will not have long-term impacts on the system. Full article

Chromium is an environmental pollutant with high toxicity and carcinogenicity. It can induce severe oxidative stress and DNA damage after entering the human body through the food chain. As a plant growth-promoting rhizobacterium (PGPR) with both heavy metal tolerance and plant growth-promoting properties, Klebsiella variicola has considerable potential for the remediation of chromium contamination. In this study, chicory served as the experimental plant to explore the mitigating impacts of K. variicola on stress induced by hexavalent chromium (Cr(VI)) at a concentration of 400 mg/kg. The results showed that chromium severely inhibited the growth of chicory. In contrast, K. variicola significantly reduced the soil chromium content. As the chromium content decreased, the activities of soil urease, sucrase, catalase, and alkaline phosphatase were restored, increasing by 32.60–53.69%. Accordingly, the contents of total phosphorus, available phosphorus, total nitrogen, available nitrogen, soil organic carbon, and available potassium also increased by 34.71–51.81%. In addition, K. variicola reversed the decline in microbial diversity induced by chromium stress, promoted the growth of beneficial bacteria such as Acidobacteriota and Chloroflexota, and enhanced the stability of soil ecosystem functions. Ultimately, the growth inhibition of chicory caused by chromium stress was alleviated, with fresh weight, root length, maximum leaf width, maximum leaf length, plant height, and stem diameter significantly increasing by 21.89–61.60%. This study enhances our comprehension of the various functions of PGPR when exposed to heavy metal stress, and provides support for the development of microbe–plant combined strategies in the remediation of chromium-contaminated soils. Full article

Soil erosion is a critical environmental issue restricting ecological security and agricultural sustainable development in China. Traditional studies have predominantly focused on physical driving factors such as hydraulic and wind erosion, while the regulatory effects of hydrochemistry on soil erosion have long been neglected. To clarify the mechanisms and regulatory processes of hydrochemistry-driven soil erosion in China, this study collected 795 relevant publications from the Web of Science Core Collection spanning from 2000 to 2025. Based on bibliometric methods, visualization software including VOSviewer 1.6.20 and CiteSpace 6.4.R1 were adopted to analyze publication trends, author distributions, research institutions, and keyword co-occurrence characteristics. The results indicated that the number of publications concerning hydrochemistry-driven soil erosion in China has increased year by year since 2000. China ranks first in total publication output, showing a dominant research position in this field. The Chinese Academy of Sciences contributed the largest number of publications among all research institutions. Keyword co-occurrence analysis over the past 25 years demonstrated that soil erosion, runoff, and water erosion serve as the core research hotspots. Further analysis revealed the regulatory mechanisms of key hydrochemical parameters (e.g., pH value, ionic strength, and dissolved organic carbon) throughout erosion processes. In-depth keyword analysis confirmed that current research on hydrochemistry-driven soil erosion in China remains at the preliminary stage, lacking comprehensive exploration of microcosmic mechanisms and systematic regulation strategies. Therefore, intensified research efforts and optimized regulatory frameworks are urgently required in future studies. This study can provide theoretical foundations and technical references for improving the understanding of erosion driving mechanisms and enhancing soil erosion management efficiency across diverse regions of China. Full article

Per- and polyfluoroalkyl substances (PFASs) constitute a chemically diverse family of persistent contaminants, the regulation of which is tightening rapidly in Europe and the United States. Granular activated carbon, selective ion exchange, and pressure-driven membranes remove many long-chain PFASs, but their performance is less robust for short-chain and ultrashort species, and all generate concentrated secondary waste streams. Hydrophobic deep eutectic solvents (DESs), including natural deep eutectic solvents (NADESs), have emerged as tunable liquid extractants able to concentrate PFASs into small solvent volumes that can be regenerated or coupled to destruction. This perspective differs from existing DES-PFAS reviews by converting qualitative solvent-selection arguments into a decision framework with explicit acceptance gates: broad PFAS affinity, a component-resolved non-migration specification for treated water, viscosity and mass-transfer limits, regenerability targets, and techno-economic/life-cycle benchmarking against incumbent processes. We refine the bifunctional DES design hypothesis by separating validated regimes from unresolved cases, identifying the reliability limits of COSMO-RS, molecular dynamics, and machine-learning screening, and defining tiered reporting requirements for early-stage studies. The central message is that PFAS-extracting DES should no longer be evaluated only by single-compound removal percentages; they must be judged as integrated, closed-loop treatment materials with solvent losses, regeneration stability, destruction compatibility, cost, and environmental impacts that are quantified from the outset. Full article

Reliable prediction of carbon allowance prices plays a crucial role in emissions trading systems, particularly for market participation, regulatory compliance, and long-term cost planning. In China, regional carbon markets differ markedly in trading activity, price formation mechanisms, and responsiveness to external signals, which limits the effectiveness of conventional single-model forecasting approaches. This study develops a unified machine learning framework designed to accommodate such cross-market heterogeneity. The framework incorporates a diverse set of explanatory variables, including historical price-based indicators, trading volume information, inter-market linkage signals, and macroeconomic factors. Three ensemble-based learning algorithms-XGBoost, LightGBM, and Random Forest—are implemented, and their outputs are further integrated using a weighted aggregation scheme to improve generalization across markets. The empirical evaluation across seven pilot markets shows that, while LightGBM consistently performs well as a standalone model, the proposed ensemble framework achieves superior stability and adaptability under varying market conditions. The forecasting accuracy is high across all cases, with coefficients of determination above 0.74 and reaching values greater than 0.92 in most markets. Further investigation through feature ablation highlights the heterogeneous role of external information, indicating that predictor importance varies significantly between markets and that no universal feature combination yields optimal performance. Leveraging the forecast outputs, the study also demonstrates practical applications in decision support, including timing strategies for allowance sales and dynamic cost assessment in offshore wind engineering scenarios. By systematically evaluating the marginal contribution of different information groups to predictive uncertainty, the framework offers a flexible tool for managing information-structure uncertainty in fragmented carbon markets. The proposed framework offers an integrated solution that connects predictive modeling with operational and engineering decision on processes, providing a flexible tool for managing uncertainty in fragmented carbon markets. Full article

Understanding how natural and anthropogenic factors jointly influence avian diversity is essential for biodiversity conservation and the sustainable management of large-scale wetland ecosystems, yet their combined effects remain insufficiently understood. This gap is particularly evident for land birds, as most studies focus on waterbirds. Using structural equation modeling, we quantified the effects of these drivers on habitat quality and avian richness in the Sanjiang Plain, separately for waterbirds and land birds. Our results show that: (1) habitat quality is primarily controlled by natural factors, particularly soil organic carbon (SOC), normalized difference vegetation index (NDVI), and topography, whereas human activities exert weak negative effects; (2) waterbirds are primarily associated with SOC- and temperature-driven pathways, whereas land birds respond more directly to climate and human disturbance; (3) natural drivers exert stronger effects than anthropogenic factors on both waterbird and land bird diversity; and (4) the effects of natural drivers differ between bird groups, with SOC and NDVI showing stronger effects on waterbirds, and precipitation and temperature being more influential for land birds. These findings highlight the need for group-specific conservation strategies, including conserving soil carbon and maintaining hydrological conditions for waterbirds, and enhancing vegetation and mitigating human disturbance for land birds. Full article

Aliphatic diamines possess two amino functional groups and exhibit diverse chemical properties and tunable molecular structures. By selecting the guest [(C₂H_2n+4N₂), n = 2–6] and host 18-crown-6, and controlling the design and assembly processes via modulation by thiocyanate and a manganese salt, a series of dumbbell-shaped crown ether complexes, (C₂H_2n+6N₂)²⁺(18-crown-6)₂[Mn(NCS)₄]²⁻·(δ_n,₂C₂H₃N), n = 2–6, (1)–(5), was synthesized and analyzed by single-crystal X-ray diffraction (SCXRD) at 100 K and 293 K. Variable-temperature infrared and XRD analyses confirmed that compounds 3 and 5 underwent a phase transition. As the length of the carbon chain increases and alternates between odd and even, the interplanar dihedral angle of the crown ether exhibits a distinct pattern: Even-number chains arrange in parallel, whereas odd-number chains form a pronounced angle. This structural pattern influences macroscopic deformation of the crystal and induces corresponding periodic variations in the dielectric and electrochemical properties. The wide-bandgap insulators and magnetic properties are primarily governed by the inorganic components of the system and are less influenced by the organic portion. This study reveals principles for regulating supramolecular conformation and functional properties through the parity of the organic chain lengths, providing a strategy for the molecular-level design of supramolecular crystal materials with ordered structures and tunable properties. Full article

Maintaining good indoor air quality (IAQ) is essential for student health, cognitive performance, and overall well-being. Traditional ventilation strategies, particularly constant air volume systems and manual window operation, often fail to maintain optimal IAQ while simultaneously increasing building energy consumption. In response, smart ventilation systems have emerged as a promising alternative capable of dynamically modulating airflow based on occupancy patterns and real-time pollutant levels. This study presents a systematic review of fourteen carefully selected peer-reviewed studies (2015–2025) that represent the most recent and methodologically robust research on smart ventilation applications in school environments across diverse climatic conditions. The selected studies encompass experimental, simulation-based, and hybrid methodologies, and classify control strategies into demand-controlled, temperature-adaptive, occupancy-based, AI-enhanced, and building management system (BMS)-integrated approaches. Collectively, the findings demonstrate measurable improvements in IAQ indicators (e.g., carbon dioxide (CO₂), particulate matter (PM_2.5), ozone (O₃), and volatile organic compounds (VOCs)) and significant energy savings, in some cases exceeding 60%, while also identifying system vulnerabilities such as fault sensitivity, short monitoring durations, and limited long-term validation. Importantly, the review reveals critical geographic and climatic research gaps, particularly in hot–arid regions where ventilation-related cooling demand is substantial, as well as limited long-term assessments in cold climates. Furthermore, although smart ventilation systems perform effectively under controlled conditions, insufficient real-world verification, user interaction analysis, and climate-specific optimization constrain broader implementation. Addressing these gaps through climate-dependent performance evaluation and long-term operational studies is essential to unlocking the full potential of smart ventilation systems in delivering healthier, energy-efficient classrooms. Full article

Soils are critical microbial habitats that support terrestrial ecosystem functioning and harbor numerous uncultured and functionally uncharacterized microbial groups. The black soil region in northeast China is a key agricultural ecosystem globally, yet the classification and functional understanding of its crucial microbial groups remain underexplored. In this study, we identified three high-completeness metagenome-assembled genomes (MAGs) from the Global Mollisols Genomic Atlas (GMGA). Phylogenetic and comparative genomic analyses identified these genomes as representing a novel evolutionary branch within the genus Flavobacterium, classified under the phylum Bacteroidota. Their novel taxonomic position is further supported by average nucleotide identity (ANI) and average amino acid identity (AAI) thresholds, demonstrating significant divergence from all known reference genomes. Functional annotation indicated that this species possesses strong plant polysaccharide degradation potential and a chemoheterotrophic lifestyle, together with environmental stress tolerance and a specialized nitrogen metabolic network adapted to agricultural inputs, thereby conferring a metabolic advantage in black soil environments characterized by high organic matter input and marked seasonal fluctuations. In addition, global distribution analysis showed that this lineage is widely distributed across diverse ecosystems and is significantly enriched in soil habitats, particularly in environments with fluctuating carbon sources and high organic matter inputs. The new species is most abundant in temperate soils, with the northeast black soil region of China emerging as a key hotspot. Based on these findings, and because no pure culture is currently available, we propose Candidatus Flavobacterium genomatis based on genome-resolved metagenomic evidence and in alignment with the International Code of Nomenclature of Prokaryotes rules for uncultivated prokaryotes. Our results expand the known species diversity of the genus Flavobacterium and suggest potential ecological roles of uncultured black-soil microbes in carbon and nitrogen cycling, including possible involvement in N₂O reduction under suitable environmental conditions. Full article