Search Results (3,511)

The Mao open-pit coal mine waste dump in Hequ, Shanxi, is a loose, anthropogenic mass accumulated over the original topography. Following a recent sliding and significant settlement event, this dump became the subject of intense stability concerns. Due to the high moisture sensitivity of its interlayered soil and coal gangue structure, rainfall infiltration can reduce internal effective stress, triggering slope instability. Although conventional geological surveys have mapped surface fractures, implementing precise, targeted drainage control requires characterizing the internal geometric structure and preferred seepage directions. To address this, this study integrates electrical resistivity tomography (ERT), surface nuclear magnetic resonance (SNMR), and spontaneous potential (SP) methods. Multiple ERT profiles (270–600 m long) were deployed across several benches at varying elevations, supplemented by fixed-point SNMR sounding over typical low-resistivity anomalies and dense SP grid scanning. The integrated results successfully delineate the internal architecture and seepage characteristics of the dump. Specifically, ERT imaging resolves the primary geoelectrical interface (tentatively inferred as the potential sliding surface) separating the overlying loose mass from the stable underlying strata while mapping the spatial extent of the inferred water accumulation zone (IWAZ). SNMR sounding quantitatively reveals a two-layer water-bearing structure at the specific sounding site, with a deep primary water-bearing zone at 45–80 m depth. Furthermore, SP inversions illuminate the seepage process, demonstrating that meteoric water deflects along the geoelectrical interface to converge laterally toward the central axis at approximately 42°, before transitioning into a high-angle vertical deep infiltration zone (61.7°) within the axial region. These findings suggest a potential engineering direction for remediating surficial fractures and designing subsurface drainage along this 1040 m bench axis, which would mitigate future landslide risks by reducing internal pore water pressure. Full article

Green synthesis of zinc oxide nanoparticles (ZnO NPs) represents a sustainable alternative to conventional chemical synthesis by employing biocatalytic systems under environmentally benign conditions. This study presents a systematic modeling approach based on Design of Experiments (DoEs) to optimize the green synthesis of ZnO nanoparticles intended for water treatment applications. Fractional factorial design was first applied to identify the most influential synthesis parameters, including precursor concentration, bio-reductant ratio, pH, temperature, and reaction time. Subsequently, response surface methodology using a D-optimal experimental design was employed to establish predictive mathematical models describing the relationships between process variables and nanoparticle size. The developed models enabled identification of optimal synthesis conditions and prediction of parameter combinations required to produce nanoparticles with targeted dimensions suitable for enhanced photocatalytic activity, antimicrobial performance, and colloidal stability. The proposed data-driven optimization strategy provides a robust, reproducible, and scalable protocol for green ZnO nanoparticle synthesis while minimizing reagent consumption and environmental impact. These findings contribute to the development of sustainable nanomaterials as the first step toward the future application of these ZnO nanoparticles as sustainable photocatalysts for water treatment. Full article

Detection of nanoplastics in drinking-water systems is only the first analytical step toward exposure interpretation; the next challenge is source attribution. This review examines molecular fingerprinting and transformation pathways that can link nanoscale polymer signals to source waters, drinking-water treatment, distribution infrastructure, packaging materials, laboratory background, or aging processes across the potable-water chain. Nanoplastics are treated here as operationally defined particles below 1 µm, including intentionally manufactured primary nanoplastics and secondary nanoplastics generated by fragmentation, abrasion, weathering, treatment, storage, or packaging stress. The synthesis evaluates how polymer identity, particle morphology, surface oxidation, additive and oligomer profiles, thermal degradation markers, matrix context, and quality assurance/quality control (QA/QC) can be combined into defensible source assignments. Analytical platforms considered include surface-enhanced Raman spectroscopy (SERS), atomic force microscopy–infrared spectroscopy (AFM-IR), optical photothermal infrared spectroscopy (O-PTIR), stimulated Raman scattering microscopy (SRS), pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), asymmetric flow field-flow fractionation coupled to Py-GC/MS (AF4-Py-GC/MS), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and chemometric workflows. The central conclusion is that source attribution cannot be inferred from polymer identity alone; robust interpretation requires convergent evidence from particle-level chemistry, polymer-specific mass, additive or marker-ion signatures, aging state, blanks, recovery, and contextual sampling design. Full article

Surface water monitoring often requires frequent and reliable sampling at locations that are difficult or unsafe to access using conventional methods. To address these constraints, unmanned aerial vehicles (UAVs) have increasingly been used as platforms for automated water collection. This paper presents a UAV-assisted water sampling system designed to provide a high degree of operational flexibility through control of sampling depth and collected volume. The proposed system can collect up to 3 L of water distributed across six individual containers, enabling a variety of sampling strategies, including discrete, composite, and multi-depth sampling. Sampling depths of up to 3.25 m can be achieved, supporting depth-resolved investigations such as stratified water-column analyses. Compared with existing UAV-based samplers, the proposed system combines configurable sampling depth, configurable sampling volume, and a multi-bottle architecture within a single platform. To support sample integrity, an automated cleaning sequence is executed before each collection step to reduce the risk of cross-contamination between samples. Experimental validation demonstrated repeatable depth deployment under controlled conditions and consistent volume-control performance, with relative errors generally within ±3% and a maximum observed deviation of 5%. In addition, a task-based analysis provided an initial characterization of the energy demand associated with the sampling process. Overall, the results indicate that the proposed architecture can support flexible and protocol-oriented water sampling operations while extending the sampling capabilities of existing UAV-based systems. Full article

Smallholder dairy farms are central to rural livelihoods in Latin America, yet feeding strategies can shift environmental burdens across climate, land, and water dimensions. This study integrated cluster analysis and life cycle assessment to identify methane-related feeding typologies and assess their environmental trade-offs in smallholder dairy farms in the Mexican highlands. Twenty-nine farms from two dairy regions were classified by k-means clustering into two methane-emission-related farm typologies, which were subsequently characterized by their observed feeding profiles: conserved-forage-dominant (Cluster 1, n = 17) and green-forage-dominant (Cluster 2, n = 12). Their environmental performance was assessed with a cradle-to-farm gate life cycle assessment following ISO 14040/14044 and ReCiPe 2016 Midpoint across 18 impact categories. Feed production and ration supply were the main hotspots, contributing 72 to 100% of the total impacts. Global warming potential averaged 2.29 and 2.47 kg CO₂-eq per kg of raw milk in Clusters 1 and 2, respectively. Within the study sample, exploratory comparisons indicated higher marine eutrophication and land use in Cluster 1, whereas Cluster 2 showed higher fine particulate matter formation, terrestrial acidification, terrestrial ecotoxicity, and human carcinogenic toxicity (nominal p < 0.05). These potential trade-offs require validation in larger cohorts and with more geographically representative inventories. These findings show that similar milk outputs can arise from distinct feeding pathways with different environmental trade-offs and that greater reliance on fresh forage does not necessarily imply a more favorable environmental profile. Cluster-based characterization offers a practical basis for improving feed sourcing and ration design in dairy systems facing resource constraints. Full article

The implementation of water reuse strategies requires robust Decision-Support Tools (DSTs) capable of integrating legal, environmental, site-specific, and technological aspects. However, existing approaches are often limited by fragmented methodologies or high data and modelling requirements, restricting their applicability in early-stage planning. This study presents the development and validation of LëtzREUSE, a DST designed to support the selection of treatment technologies for the reuse of urban water sources, including rainwater, stormwater, light greywater, and wastewater treatment plant (WWTP) effluents. The tool is based on a parameter-driven framework that combines (i) regulatory compliance as a first filtering step, (ii) technology applicability defined through operational thresholds linked to water quality parameters, and (iii) prediction of treatment performance along treatment trains. In contrast to multi-criteria approaches, the methodology avoids subjective weighting by directly linking input water quality to process feasibility and expected effluent characteristics. Additionally, ecotoxicological risk is quantified through risk quotient (RQ) reduction, enabling the evaluation of environmental relevance alongside technical performance. The DST was validated using experimental data from the Bleesbruck WWTP, where measured influent characteristics were used to assess the performance of the tool. The results demonstrate that the tool successfully identifies feasible technologies, with Granular Activated Carbon (GAC) + UV (Ultraviolet light) and UV/H₂O₂ + GAC emerging as the most suitable options. By providing the expected quality parameters, both treatment trains can be compared. The final decision should be based on other parameters such as operational complexity. Full article

Compared with inland areas, coastal fair-faced concrete (CFFC) in coastal environments is subject to more severe environmental erosion during its service life. An inappropriate mix design can lead to the failure of concrete structures. It is therefore necessary to develop appropriate mix designs and conduct research into their performance. The orthogonal method was combined to study the influence laws of four factors, namely water-cement ratio (W/B), cement content (W_C), fly ash content (W_FA), and microbead content (W_BM), on the slump (Sp), mechanical properties (f_c^7d, f_c^28d), and apparent porosity properties (SM) of CFFC. After verification, the durability of CFFC with the optimal ratio was further examined. The results show that the order of influence of each factor on Sp, f_c^7d, f_c^28d, and SM is: W/B > W_C > W_BM > W_FA, W_FA > W/B > W_C > W_BM, W/B > W_C > W_FA > W_BM, W_C > W/B > W_FA > W_BM, respectively. The SF and flowability of CFFC with the optimal ratio are 198 mm and 579 mm, respectively; the corresponding f_c^7d and f_c^28d are 45.06 MPa and 64.03 MPa, respectively; and the maximum pore diameter, surface pore area ratio, and standard deviation of the pore distribution of the optimal CFFC are 2.14 mm, 0.31%, and 1.52 mm, respectively. The 84 d rapid chloride penetration coefficient, 28 d maximum carbonation depth, and 28 d shrinkage of the optimal CFFC are 2.1 × 10⁻¹² m²/s, 5.6 mm, and 405 µε, respectively. When prepared using the optimal mix proportions, CFFC can meet the requirements for high-performance fair-faced concrete projects in coastal areas, thereby providing valuable guidance for the practical applications of CFFC in coastal engineering. Full article

Electricity spot markets with time-of-use pricing create hour-by-hour variations in the economic value of thermal adjustments, requiring coal-fired units to adapt cold-end operation to real-time price signals. However, the nonlinear coupling between circulating water flow and condenser backpressure remains insufficiently characterized across the full operating envelope, and existing optimization strategies target steady-state heat consumption without accounting for the time-varying economic value of identical thermal adjustments under spot pricing. This study develops a quasi-steady-state thermodynamic–economic model that links real-time electricity prices with the nonlinear heat-transfer response of the circulating water system. The model enables the adaptive selection of pump combinations and blade-opening angles by balancing marginal pump power savings against marginal turbine output losses under time-of-use price signals. Using actual electricity spot market data from Zhejiang Province, simulations under different seasonal conditions show clear economic gains. The maximum hourly saving reaches 2190.79 CNY during summer negative-price periods, which is about 5.3 times higher than that in winter, while backpressure deviations remain within 12.5% of the design value. The seasonal disparity is governed by the initial heat exchange driving force, a fundamental thermodynamic property amplified by the negative-price superposition effect. The framework establishes a physical basis for market-responsive cold-end regulation across seasonal and load conditions, supporting the economic dispatch of coal-fired units in spot market environments. Full article

Single-use pyrotechnic and compressed-gas actuators currently meet industrial safety tasks that demand rapid response and high force. An integrated hydrogen production and combustion-driven actuation system is proposed as a clean and reusable alternative. Hydrogen is generated on demand inside the unit by water electrolysis. It is stored in a metal hydride module and burned with air under controlled conditions to drive a double-piston mechanism. A combined approach of modeling, such as thermodynamic analysis, ideal gas laws, and Engineering Equation Solver (EES) simulations, was used to predict the hydrogen demand and system performance. In addition, the combustion behavior and chamber pressure distribution were investigated using COMSOL Multiphysics. It was shown that hydrogen–air combustion allows for more stable and controllable operating conditions than hydrogen–oxygen combustion, while still satisfying the required in-cylinder pressure of about 350 bar. The designed proton exchange membrane (PEM) electrolyzer consumes about 221 W of power from a 24 V DC power source and produces 0.16 g of hydrogen in 135 s, which is sufficient for a high-force actuation stroke. Unlike conventional pyrotechnic cartridges and pneumatic and hydraulic actuators, the suggested system generates no solid combustion residues and does not require single-use consumables. It is reusable for many cycles, with water vapor as the main combustion product. Overall, the findings support hydrogen-powered actuation on demand as a viable and clean option for high-force safety tasks, ranging from closing emergency shut-off valves at oil and gas facilities to pressurizing fire protection and other safety systems, making it particularly attractive for remote facilities without a continuous grid power supply. Full article

High-salinity waters, including seawater, brines, and saline radioactive effluents, contain recoverable uranium or require uranium removal, but their complex chemistry complicates both capture and regeneration. Under seawater-relevant conditions, U(VI) occurs mainly as uranyl carbonate complexes and ternary uranyl carbonate complexes containing Ca²⁺ or Mg²⁺ rather than as free UO₂²⁺. Selective separation therefore depends on coupled transport, hydration-shell reorganization, carbonate displacement, and interfacial coordination. Conventional sorbents largely optimize binding strength and adsorption capacity, often at the expense of harsh stripping and secondary waste. This review frames thermoresponsive uranium separation as a coupled aqueous-speciation, interfacial-state, and process-design problem. It examines how LCST and UCST transitions, polymer-brush reorganization, hydration-layer reconstruction, pore gating, and localized photothermal heating regulate access to binding sites and release pathways. Polymer brushes, hydrogels and microgels, membranes and nanochannels, ion-imprinted magnetic composites, and MXene-based hybrids are critically compared using cycle-level criteria, including U/V selectivity, switching time, regeneration demand, energy input, fouling resistance, material loss, synthesis reproducibility, and environmental performance. Particular emphasis is placed on distinguishing genuine structural gating from the generic effects of temperature on diffusion, ligand exchange, and adsorption equilibria. Current evidence supports the feasibility of programmable capture–release interfaces but remains limited by matrix-dependent transition windows, incomplete mechanistic attribution, scarce quantitative energy and temperature-gradient data, short cycling tests, and limited device-scale validation. Progress will require standardized testing in realistic saline matrices and complete capture–release mass and energy balances rather than evaluation by maximum adsorption capacity alone. Full article

Material selection is crucial to hard tissue regeneration, and matching scaffold properties to those of the target tissue can improve clinical outcomes. This study compared the physicochemical, mechanical, and biological performance of fibrous scaffolds fabricated from polycaprolactone (PCL), polydioxanone (PDO), and gelatin methacryloyl (GelMA) for hard tissue regeneration. Polymeric fibers were produced by electrospinning, and their morphological, physical, and mechanical properties were characterized by scanning electron microscopy (SEM, n = 2), swelling and degradation analyses (n = 8), water contact angle measurements (n = 16), and tensile testing (n = 8). In addition, periodontal ligament stem cells (PDLSCs), alveolar bone marrow stem cells (aBMSCs), and dental pulp stem cells (DPSCs) were seeded onto the scaffolds to evaluate cell spreading (n = 4), viability (n = 8), and mineralized matrix formation (n = 6). Data were analyzed using one- or two-way ANOVA followed by appropriate post hoc tests (α = 5%). All polymers formed homogeneous fibrous scaffolds, with diameters within the nanoscale range. PDO and GelMA showed higher swelling than PCL, while PCL retained approximately 95% of its initial mass after three months. PCL and PDO showed higher elongation at break, tensile strength, and Young’s modulus than GelMA. Both PDO and GelMA displayed contact angles below 90°, with GelMA showing the lowest values. In vitro, all polymers were cytocompatible: PDO and GelMA enhanced DPSC viability at 7 days, whereas GelMA produced the highest viability for PDLSCs and aBMSCs at that time point. GelMA also promoted the highest mineralized matrix formation for DPSCs and PDLSCs, with no significant differences among polymers for aBMSCs. Overall, GelMA scaffolds promoted greater cell viability and mineralized matrix formation, while PCL and PDO provided superior mechanical properties, highlighting the importance of balancing biological and mechanical requirements when designing scaffolds for hard tissue regeneration. Full article

The increasing pressure on water resources is one of the most critical challenges of the 21st century. Demographic, industrial, and climatic factors are drastically reducing the availability of fresh water, with particularly pronounced effects in arid regions and the Mediterranean basin. Agriculture, which accounts for about 70% of global water withdrawals, is at the centre of this crisis, making it essential to explore unconventional sources such as brackish water. Desalination emerges as a key technology to address this challenge. Electrodialysis offers an attractive alternative, particularly suitable for moderately salty water (1000–5000 mg/L of total dissolved solids), thanks to its energy efficiency within specific salinity ranges and the ability to precisely control the quality of the produced water. At the same time, agrivoltaic systems that integrate energy production and agriculture are spreading, requiring compact, modular treatment devices that can be integrated with renewable sources. This research objective is the design and building of an affordable and reproducible electrodialysis (ED) prototype, equipping the system with automated sensor-based control, validating the device performance on brackish water and analyzing the feasibility of integration in agrivoltaic contexts. Full article

Urban development increases impervious surfaces and stormwater runoff, while the construction sector generates large volumes of construction and demolition waste (CDW). Pervious concrete can mitigate runoff through infiltration and may also valorize CDW, yet its production and testing procedures remain heterogeneous, particularly with recycled aggregates. This study experimentally screens practical processing parameters for pervious concrete produced with basalt and CDW coarse aggregates. The influence of chemical admixture, consolidation method, and end-surface preparation was first assessed to define suitable production conditions: adequate cohesion without admixture required raising the water-to-cement ratio from 0.30 to 0.65; high-energy Proctor compaction crushed the CDW aggregates, favoring standard tamping-rod consolidation; and end-surface preparation had only a minor effect on compressive strength. The selected procedures were then applied to an ACI 522R-based basalt mixture designed for a target void content of 25%, which achieved a fresh density of 1985 kg/m³, a void ratio of 16.88%, and a mean permeability coefficient of 12.18 × 10⁻³ m/s, about twelve times the minimum required by ABNT NBR 16416. Its 28-day compressive strength (12.75 MPa) remained below the 20 MPa pavement-surfacing requirements, although within the typical range reported by ACI 522R for pervious concrete (2.8 to 28 MPa). Overall, aggregate gradation, compaction procedure, and admixture-enabled paste cohesion emerged as the dominant factors governing the strength–porosity–permeability trade-off, guiding subsequent mix optimization. Full article

In this study, the performance of eco-friendly concrete produced by utilizing waste marble as a total aggregate replacement was evaluated. The experimental findings indicated that the developed waste marble aggregate concrete (WMC) specimens successfully met the standardized strength requirements for structural applications. The main objective of this investigation was to determine the experimental and statistical correlation between destructive strength tests and the non-destructive ultrasonic pulse velocity (UPV) test, taking into account the content ratios of concrete. This study presents an experimental and statistical investigation to correlate destructive strength properties with non-destructive UPV measurements in eco-friendly concrete. A total of 300 concrete cubic specimens were produced by fully substituting conventional aggregates with waste marble aggregates across five distinct water-to-cement ratios (W/C = 0.20 to 0.40) and ten aggregate-to-cement ratios (WMA/C = 1.1 to 2.0). Compressive strength (f_c), splitting tensile strength (f_t), and UPV tests were conducted on the 28th day. The experimental results showed that f_c ranged from 19.2 to 37.5 MPa, f_t from 2.3 to 4.4 MPa, and UPV from 3580 to 4386 m/s, confirming the high structural quality of the waste marble aggregate concrete. Non-linear regression analyses were performed using IBM SPSS Statistics 22 to develop empirical models predicting destructive strengths based on mix design parameters and UPV data. The proposed statistical models demonstrated high accuracy with determination coefficients (R²) of 0.98 for f_c and 0.97 for f_t, backed by low mean absolute relative deviations (6% and 8%, respectively). The findings indicate that the developed empirical formulations can reliably evaluate the strength of WMC in a practical and non-destructive manner. Full article

This study presents the development of a combined heating system for a bioreactor designed to improve the efficiency of organic waste biodegradation. The proposed system maintains the required operating temperature within a specified range without relying on external energy sources, thereby enhancing the sustainability and energy efficiency of the bioconversion process. A bioreactor heating system based on a “water jacket” that is heated by the combustion of coal–water fuel has been developed. The “water jacket” is a system of two 15 mm diameter tubes located along a cylindrical axis inside the bioreactor. Heated liquid flows through the tubes, accelerating biomass fermentation processes. A technology for preparing and burning coal–water fuel using a radial circulation injection device is offered. Calculations are performed to determine the optimal temperature regime for the combustion process. Optimal conditions for electric pulse coal grinding (28 kV, 600 discharges) were established, the required particle size distribution of 50–250 µm was achieved, and the ignition temperature of the coal–water mixture (650 °C) was determined. The findings may contribute to improved waste management technologies and environmental sustainability by reducing carbon emissions and waste generation. Full article