Search Results (852)

When bridge towers are subjected to strong winds, they exhibit significant displacements. This displacement change can serve as an important indicator for structural performance warning. The displacement and acceleration collected in real time by the intelligent bridge monitoring system are disturbed by various noises, resulting in missed alarms in the monitoring system and causing huge economic losses. This study employs the fractional-order Butterworth lowpass filter method, eliminating the maximum value method, triple standard deviation method, etc. for preprocessing abnormal monitoring data characterized by missing values and outlier points. A fractional-order multi-rate Kalman fusion is proposed to process and model the correlation of structural displacement and acceleration data, and the simulated data and measured data are analyzed and verified respectively. Spectral analysis confirmed that by effectively fusing the low-frequency GPS signal with the high-frequency accelerometer signal, the fractional-order multi-rate Kalman fusion displacement measurement has a relatively high accuracy. Displacements obtained by the fractional-order multi-rate Kalman fusion method are adopted for correlation modeling, and residuals generated from this fractional-order fusion modeling are used for structural performance warning testing. The effectiveness of this structural performance warning is quantitatively validated through statistical assessment of warning accuracy. Full article

Environmental tax is a key market-based instrument for promoting sustainability and reshaping corporate strategy. Using the panel data of Chinese listed firms from 2010 to 2023, this study employs text mining to measure digital transformation and examines the impact of environmental tax on corporate digitalization. The results show that environmental tax significantly promotes digital transformation. The mechanism analyses reveal that green technology innovation and ESG performance serve as important transmission channels. Furthermore, the effect is positively moderated by regional marketization, environmental information disclosure, and low-carbon city policies. The heterogeneity analyses indicate stronger effects in economically developed regions and firms with greater resource endowments. The additional analysis demonstrates that environmental tax enhances both total factor productivity and green governance performance through accelerating digital transformation, achieving a synergistic green–digital transition. This study provides empirical evidence on how market-based environmental policies can foster corporate digital transformation as a pathway toward sustainable development. Full article

Within the hospitality sector, restaurants face growing pressure to integrate sustainable practices while maintaining economic viability. Two fundamental questions remain: do sustainability practices command price premiums, and does this relationship vary across market segments? This study employs dictionary-based text analysis to quantify sustainability practices from approximately 4.4 million consumer reviews spanning 38,930 U.S. restaurants (2018–2023). We make two methodological contributions: First, we identify a measurement artifact—sigmoid normalization applied to sparse keyword data can inflate regression coefficients by 25–44×—and we propose a log-density transformation that preserves measurement validity. Second, using hedonic pricing models with city and cuisine fixed effects, ordered logit specifications, and interaction models, we document a monotonically decreasing relationship between restaurant quality and sustainability-associated price premiums. Lower-rated establishments (<3.0 stars) exhibit a positive premium of +2.60%, mid-tier restaurants (3.0–4.0 stars) exhibit −0.61%, and higher-rated establishments (>4.0 stars) exhibit −2.06%. The interaction between sustainability and star rating is strongly negative (${\beta }_{\mathrm{int}}=-0.042$, $p<0.001$), indicating that sustainability’s marginal pricing association diminishes by approximately 4.2 percentage points per additional star. These results suggest that sustainability functions as a quality signal in lower-tier markets but transitions to a baseline expectation in higher-quality segments. The findings inform differentiated strategies for restaurant operators, certification bodies, and policymakers. Full article

Subsequent backfilling mining methods are critical technologies for the safe exploitation of deep metal mines, while the resource utilization of ultrafine tailings is a core component of green mining practices. This study focuses on the ultrafine tailings from the Tianxing iron mine to investigate the preparation and optimization of backfill slurry. The goal is to develop a low-cost, high-strength slurry suitable for large-scale preparation and long-distance pipeline transportation. The main findings are as follows: the 6920-type anionic flocculant was identified as the optimal agent, with an optimal dosage of 20 g/t, achieving an underflow concentration of 70.1% under dynamic testing conditions; a novel cementitious material (NCM) exhibited a 28-day uniaxial compressive strength of 3.14 MPa at a low binder-to-tailings ratio of 1:10, outperforming ordinary Portland cement and Slag Micro-powder; and the optimal slurry concentration was determined to be 70%, which provides a favorable balance between mechanical strength and flowability. Furthermore, economic analysis indicates that adopting NCM can reduce annual backfilling costs by approximately 13 million RMB. By establishing an integrated technical framework that includes “property characterization–flocculation optimization–binder selection–rheological regulation,” this study addresses key technical challenges associated with ultrafine tailings backfilling, significantly reduces binder consumption and overall backfilling costs, and provides precise parameter guidance for industrial-scale applications. The proposed approach demonstrates significant practical value for promoting green and sustainable mining development. Full article

Coal continues to play a significant role in Poland’s electricity generation system, making the sustainable management of environmental impacts from hard coal mining a critical challenge during the ongoing energy transition. In line with the European Green Deal and circular economy principles, reducing and managing mining-related waste emissions is an important component of sustainable development in regions undergoing a gradual phase-out of fossil fuel extraction. This study analyzes rock mass and dust emissions associated with underground hard coal mining in Poland over the period 2017–2025 using the most recent statistical data, including estimates for 2025 based on the first three quarters of the year. The scale, structure, and trends of emissions are examined to assess their implications for environmental sustainability, resource efficiency, and long-term land use. Particular attention is paid to the relationship between declining coal production and the relatively slower reduction in waste rock emissions, which indicates increasing contamination of extracted material and poses challenges for sustainable mining practices. The results show that while total coal output has decreased substantially, reductions in rock mass emissions have been less dynamic, highlighting the need for improved waste management strategies from a sustainability perspective. The study demonstrates that increasing the utilization of mining waste, through underground use and circular economy applications, can reduce environmental pressure, support compliance with sustainability policies, and mitigate long-term impacts on post-mining regions. Although the analysis focuses on Poland, the findings provide transferable insights for other countries seeking to balance energy security, mining sector restructuring, and sustainable development objectives during the transition away from fossil fuels. Full article

Against the backdrop of global digitalization and green development, digital innovation ecosystems have emerged as key drivers for advancing regional green innovation cooperation and achieving sustainable development goals. This study constructs a theoretical analytical framework encompassing “Actor-Resource-Environment.” Utilizing panel data from 30 Chinese provinces spanning 2012–2022, it employs machine learning and dynamic QCA methods to dissect the dynamic causal relationship between digital innovation ecosystems and regional green innovation cooperation. Key findings include: (1) Green innovation cooperation networks are evolving from a “core-periphery structure” toward new characteristics of multi-centered mutual coupling and coordination. (2) Different machine learning models yield varying effects on how digital innovation ecosystems influence regional green innovation cooperation, with the XGBoost model demonstrating the strongest performance. (3) No single element within the digital innovation ecosystem can serve as a necessary condition for driving regional green innovation cooperation. (4) Three configuration patterns emerge for achieving high-level regional green innovation cooperation, with digital innovation funding, digital talent resources, and digitally inclusive financial environments consistently serving as core prerequisites. These findings deepen our understanding of the complex causal mechanisms involving multi-factor matching and linkage that influence regional green innovation cooperation, offering valuable insights for advancing high-quality regional green innovation development. The research findings reveal the complex configuration pathways through which multidimensional elements of the digital innovation ecosystem collectively drive regional green innovation cooperation. This provides practical governance pathways for breaking down regional barriers and building highly resilient green innovation cooperation networks. Full article

Mining-resource-based cities, as distinctive human–environment systems, face urgent challenges from intensified urbanization and mining, leading to land imbalance and ecosystem service degradation. To enhance resilience, it is essential to identify the evolution and drivers of ecosystem services and construct targeted ecological compensation models. This study focuses on Xinzhou, a representative mining city in China, and systematically analyzes three aspects: (1) spatiotemporal dynamics of land use and ecosystem service value (ESV) from 2000 to 2023 using Markov chains, equivalent factor method, hotspot and sensitivity analyses; (2) identification of ESV driving mechanisms through an integrated “stepwise regression + geographical detector” framework; and (3) formulation of ecological compensation models via quantification of priority indices, demand intensity coefficients, and compensation standards. Key findings indicate that land conversion was concentrated in coalfield zones and surrounding built-up areas, involving 2,518,341.75 hm² (35.76% of total area), primarily characterized by a reduction in farmland and expansion of forest, grassland, and construction land. ESV showed a striped spatial pattern, with higher values in mountainous zones and lower values in valleys and basins with frequent human activity. The northwest coalfield region experienced an initial decline followed by a recovery in ESV. Annual mean temperature emerged as the dominant driver, while DEM influence increased annually. All factor interactions exhibited synergistic effects, with natural variables exerting greater influence than socio-economic ones. Ecological compensation demand was high overall, especially in Wutai, Kelan, and Pianguan counties, with high-value compensation areas mainly distributed in the eastern and central parts of Xinzhou. Looking ahead, a compensation framework prioritizing ecological–economic optimization should be developed, guided by zoned, typological, and dynamic configurations. By analyzing ecosystem governance from the perspective of a mining-resource-based city, this study enhances global ecosystem service evaluation frameworks and offers a replicable model to advance transnational ecological cooperation and green urban transformation. Full article

The accelerated closure of hard coal mines across Europe contrasts with Poland’s continued structural reliance on coal extraction and coal-based power generation, increasing the urgency of credible post-mining development models. This article investigates the potential transformation of the end-of-life Bobrek coal mine in Bytom (Poland), drawing on methodological and business-model insights from the European Union (EU) Research Fund for Coal and Steel (RFCS) POTENTIALS and GreenJOBS projects. A combined methodological framework is applied, including structural analysis to identify key transformation variables, morphological analysis to explore alternative redevelopment pathways, and multicriteria assessment to configure coherent scenarios integrating renewable energy systems and circular-economy activities. The results show that an industrial eco-park backed by a virtual power plant (VPP), comprising photovoltaic installations, a mine-water-based geothermal heating system, and small-scale wind turbines, is technically feasible and environmentally sustainable. In parallel, three circular-economy business lines, the recycling of end-of-life photovoltaic panels, waste electrical and electronic equipment (WEEE), and refrigeration units, were assessed as possible economic cores of the envisaged eco-park. Overall, the proposed model enables effective reuse of mining infrastructure, supports low-emission industrial activity, and aligns with EU climate policy objectives. The Bobrek site may serve as a reference for post-mining redevelopment in other coal regions. Full article

In the context of deep mining and green low-carbon transition, this study characterizes the thermo-mechanical evolution and fracture mechanisms of cemented tailings backfill (CTB) through systematic experiments conducted at 20–60 °C across 3–28 days. Results demonstrate that strength and elastic modulus follow a unimodal dependence on temperature, peaking at 40 °C. Gaussian modeling reveals that curing times narrow the thermal tolerance window, with the elastic modulus exhibiting higher sensitivity to overheating. A consistent “pre-peak activity window” is identified in AE responses, characterized by b-value drops and an increase in tensile event proportions from 66% to 83%. A composite AE damage index (ADI) is introduced to systematically precede macroscopic failure, with thresholds of ADI ≥ 0.60 and 0.70 indicating accelerated crack propagation and imminent instability, respectively. Microstructural analysis confirms that 40 °C promotes C-S-H and fine ettringite bridging, whereas temperatures ≥ 50 °C induce Ca(OH)₂ coarsening and enhanced pore connectivity, triggering early tensile-dominated degradation. This study establishes a “temperature → hydration/porosity → AE response → mechanical evolution” pathway, providing an optimal curing window of 40 ± 5 °C and an ADI-based early-warning criterion for temperature-adaptive CTB design and on-site safety management. Full article

Failure to fully backfill the goaf may result in increased exposure of roof strata, significantly raising the risk of roof collapses in mining zones and potentially causing surface subsidence, thereby endangering the safety of mining personnel. To address this issue, expansive agents are utilized to produce active roof-contact backfill (ARCB) materials, which promote localized self-compaction of backfill materials in unroof-contact areas through hydration reactions. In this study, an isothermal calorimeter was employed to measure the ARCB hydration heat release rate curves of three types of expansive agents, CaO-based, MgO-based, and ettringite-based, at dosages ranging from 6% to 12%. Hydration kinetic parameters were calculated based on the Krstulovic–Dabic model. The influence of expansive agent type and dosage on these parameters was analyzed, and the hydration mechanism of ARCB materials was investigated. The results indicate that the hydration process of grouting materials using all three expansive agents follows five distinct stages: rapid reaction, induction, acceleration, deceleration, and decay. However, increasing the dosage of the CaO-based expansive agent will enhance heat release and prolong the duration of the acceleration stage. When the dosage is 12%, the total heat release reaches 327.4 J·g⁻¹. At the same dose, the sample doped with MgO-based expansive agent was only 254.3 J·g⁻¹, which was 22.3% lower than that of CaO-based, and the occurrence time of the second heat release peak was earlier. In contrast, the ettringite-based expansive agent shows a decreasing trend in heat release with increasing dosage. Furthermore, the use of CaO-based and MgO-based expansive agents allows the hydration process to bypass the phase boundary reaction (I) stage and directly enter the diffusion (D) stage. Ettringite-based expansive agents still undergo three stages, but exhibit a shortened nucleation and growth (NG) stage and an extended induction stage. Additionally, different expansive agents have varying effects on the crystal growth index (n), reaction rate constant, and degree of hydration. Full article

The global lithium supply balance has been under pressure since the recent increase in demand for electric vehicles. Conventional techniques for lithium extraction from natural resources are solar evaporation and hard-rock mining, which both have their limitations in view of sustainability. The question arises whether these methods will suffice for a responsible supply to provide the necessary materials for the emerging green economy. While new technologies for the valorization of lithium from unconventional resources like geothermal brines, salt lakes and seawater are in the pipeline, they are yet to be proven on an industrial scale. Membrane technology, ion-exchange adsorption and electrochemical methods are the current focus of several players in the pilot stage of their announced lithium carbonate or hydroxide production process. These technologies have various advantages and disadvantages in terms of energy consumption, selectivity and process costs, and the optimal choice remains dependent on local factors such as brine composition, energy availability and reagent cost. There are currently several DLE projects in the pilot phase, which is a significant step towards more sustainable lithium supply. Proving the economic and technical viability of these methods for extracting lithium from unconventional sources would increase the amount of globally proven reserves while diversifying and de-risking the supply chain, which is currently heavily dominated by a small number of countries. Full article

Leucoptera malifoliella has become a severe leaf-mining pest in Chinese apple orchards, especially under expanding organic and green cultivation practices, with effective management hindered by insufficient contemporary ecological data. To fill this gap, this 2023–2025 study conducted in Shijiazhuang, Hebei, combined field monitoring, morphological analysis, flight mill assays, and parasitoid release trials to clarify the moth’s phenology, develop rapid pupal sexing methods, quantify adult flight capacity, and assess Trichogramma dendrolimi biocontrol potential. The results showed five annual generations (overwintering as pupae), peak damage in July–August, and marked generational overlap. A reliable pupal sexing method was established via genital opening morphology. Adult flight peaked at 3 days post-emergence (max distance: 1.223 km), with no sexual dimorphism. Timely T. dendrolimi releases boosted parasitism rates, achieving 23.4–49.6% control efficacy during peak damage, with the parasitism rate positively correlated with efficacy. This study confirms the moth’s potential for generational increase under climate warming and medium-distance dispersal capacity, validating Trichogramma’s utility and laying a scientific foundation for precise, regionally coordinated ecological management. Full article

During coal mining, the development of joint fractures in overlying rock strata is one of the key factors that degrade the mechanical properties of rock masses, form water-conducting fracture zones, and induce safety hazards. To investigate the fracture evolution characteristics of overlying strata during coal extraction under thick and hard roof conditions, this study established a mining physical model based on similarity simulation technology, tracked the fracture evolution process, and performed quantitative analysis using fractal theory. The results show that fracture development is significantly correlated with the mining advance distance: the fractal dimension of fractures is small in the initial mining stage and gradually increases as the working face advances. When the mining width exceeds the ultimate span of the roof, local fractures expand rapidly with a sharp rise in the fractal dimension to 1.436; further increasing the mining width triggers large-scale sudden fracture expansion, resulting in severe degradation of rock mass integrity, with the maximum fractal dimension reaching 1.445. The research findings provide theoretical references for safety management and disaster prevention in coal mining under thick and hard roof conditions. Full article

Lightweight concretes have gained great momentum in construction in the last decade, due to the large number of sustainable characteristics and construction advantages associated with them. The sustainability of lightweight concrete depends mainly on the application of sustainable aggregates, such as the amorphous opalized tuff, found in large quantities in Eastern Macedonia. It is economically viable, easy to extract from surface mines, and easy to process. The physical, chemical, and mechanical properties, porosity, and water absorption of the tuff as a stone aggregate were examined as the aim of this study, with the objective of assessing its potential application in lightweight concrete. The tuff showed an average bulk density 87.2% lower than that of limestone. The compressive strength of the tested opalized tuff samples was 41.16 MPa, or 48.5% of the average strength of limestone rock (84.88 MPa). Furthermore, three concrete mixes with different aggregates were tested: with 100% limestone, with 50% tuff and 50% limestone, and with 100% tuff. The increase in the amount of tuff in the concrete mix required a larger amount of water, due to the high porosity of the tuff; the high water absorption of the tuff aggregate reduced the consistency of the concrete mix, so the bulk density decreased significantly with increasing tuff content. The concrete with 100% tuff aggregate was 44% lighter than concrete with 100% limestone aggregate, which means that concrete–tuff mixes can be classified as lightweight concrete. Our results further showed that by increasing the amount of opalized tuff aggregate in the concrete, the compressive strength of the hardened concrete decreased. The 50:50 mix showed an average compressive strength of 25.68 MPa at 28 days, i.e., 42% lower than the average compressive strength for limestone concrete (44.27 MPa). The tuff-only mix exhibited a compressive strength of 10.46 MPa that was 76.4% lower than limestone-only concrete. The increase in the amount of tuff in the concrete was shown to reduce the thermal conductivity; i.e., concrete with tuff aggregate showed a thermal conductivity coefficient of 0.3585 W/m·K, which is 5.58 times lower than that of conventional concrete with limestone aggregate. The results from the laboratory analyses provide guidance for the application of the local amorphous opalized tuff as a natural stone and as a filler for producing lightweight mortars and concretes. Every alternative and possibility for its application would contribute to reducing waste, reducing energy consumption in buildings, and thus creating an ecologically safe environment. The application of opalized tuff in lightweight concrete will support green jobs and the circular economy using locally available, alternative material, through reducing transportation emissions and decreasing waste. Full article

Methane is a potent greenhouse gas with strong climate and health impacts, largely originating from coal mining, agriculture, and waste management. This article aims to assess methane emissions at the global, regional, and national levels, with a particular focus on coal mining and its mitigation potential in Poland and Spain. The analysis integrates data from authoritative international and national databases, including time-series evaluation, spatial visualization, and comparative case studies. Results indicate that agriculture, energy, and waste remain the dominant global methane sources, while coal mining continues to play a significant role in Europe, especially in Poland. Case studies from Polish coal mines demonstrate that substantial emission reductions can be achieved through methane drainage, ventilation air methane oxidation, and energy recovery systems, often at low or negative net cost. In contrast, Spain’s coal-related methane emissions are now primarily associated with abandoned mines, highlighting the importance of long-term monitoring and post-mining management. The findings confirm that targeted technological measures combined with robust monitoring, reporting, and verification frameworks and supportive regulation can significantly reduce methane emissions and transform coal mine methane from a climate liability into a valuable energy resource. Full article