Search Results (29,591)

The functional performance and structural integrity of natural rock materials under fluctuating environmental stressors are pivotal for their advanced applications. As a non-ionizing and radiation-free technology, terahertz (THz) spectroscopy offers a safe and promising alternative for non-destructive testing (NDT), uniquely capable of being deployed in open and unshielded environments. However, limited penetration depth, exacerbated by both the dense geological matrix and the extreme sensitivity of THz waves to moisture states, has long hindered its widespread application in rock characterization. This study establishes a quantitative Terahertz Time-Domain Spectroscopy (THz-TDS) framework to characterize four lithologies under drying–wetting cycles. Exponential signal attenuation across thicknesses was quantified based on the Beer–Lambert law, with attenuation coefficients ranging from 0.15 to 0.74 per millimeter. Planar transmission imaging successfully visualizes lithologic and moisture-dependent heterogeneity: limestone exhibits a dense, homogeneous structure with stable amplitude distribution; sandstone and purple sandstone show parallel statistical trends, reflecting uniform pore networks; and granite demonstrates the most pronounced imaging contrast under varying moisture states, driven by complex grain-boundary scattering. The findings reveal that THz transmission is dictated by the synergistic effects of mineral compositions and pore structures: scattering at grain boundaries and fractures leads to significant energy dissipation, whereas clay-rich lithologies exhibit the highest sensitivity to moisture variations due to water adsorption and interfacial polarization effects. As an exploration of THz technology in the non-destructive evaluation of rock materials, these findings establish an analytical framework for the quantitative assessment of microstructure evolution. Full article

Snow cover plays an important role in ecological stability and seasonal water regulation in the western Greater Khingan Mountains of Inner Mongolia, a cold-region transitional zone where climate warming may intensify environmental vulnerability and sustainability challenges. Using long-term remote sensing, meteorological, and topographic datasets, this study examined the spatiotemporal changes in snow cover and assessed the relative influences of climatic and geographic factors. The results showed pronounced spatial heterogeneity, with greater snow depth and longer snow cover duration occurring in the northeastern, high-altitude, gentle-slope, and north-facing areas. Snow depth showed a slight but marginally significant declining trend during 1982–2024 at a rate of 0.026 cm a⁻¹, while snow cover days decreased by 0.39 d a⁻¹ during 1982–2020. Snow cover onset exhibited a slight but significant delay, whereas snowmelt timing showed strong interannual variability. Compared with precipitation, temperature showed stronger and more persistent associations with snow cover variations, and climatic factors explained a larger proportion of snow-depth variability than geographic factors. Overall, the results suggest that regional warming has played a leading role in recent snow cover decline. These findings improve understanding of climate-sensitive snow dynamics and provide useful evidence for ecological conservation, seasonal water-resource adaptation, and sustainable regional management in cold-region landscapes of northern China. Full article

Supercritical carbon dioxide (SC-CO₂) fracturing has emerged as an environmentally friendly alternative to conventional water-based hydraulic fracturing; however, its inherently low viscosity restricts proppant-carrying efficiency and reduces fracture conductivity. To address this limitation, this study systematically investigates the rheological behavior and sand-carrying mechanisms of CO₂ dry fracturing fluid under various thermodynamic and compositional conditions. Rheological measurements were conducted to evaluate the effects of thickener concentration, temperature, and pressure on viscosity, while visualized experiments were performed to examine the influence of injection rate, sand ratio, thickener concentration, and temperature on proppant migration and deposition. A numerical model developed in Fluent was further employed to simulate the temporal evolution of proppant transport within the fracture. The results show that higher thickener concentrations and injection rates significantly enhance proppant transport distance and uniformity, whereas elevated temperature and sand ratio promote localized settling. The simulation results agree well with the experimental observations, validating the model’s reliability. This study elucidates the coupled effects of rheology and operating parameters on CO₂ dry fracturing behavior and provides theoretical and experimental guidance for optimizing CO₂-based fracturing fluids in low-permeability reservoirs. Full article

Nanocomposite materials combine diverse material properties to form multifunctional structures, enhancing the efficiency of conventional applications. Particularly in environmental monitoring, such as water analysis, nanocomposites significantly improve sensitivity and lower costs associated with standard analysis methods. The SERS method is gaining popularity due to its operational simplicity, on-site applicability, and rapid results delivery. This study focused on the development of a multifunctional metal-chitosan-based nanocomposite utilizing an economical, eco-friendly approach as an SERS substrate. The resulting composite exhibits considerable preconcentration capabilities and will provide low detection limits (LOD) for future SERS applications. Specifically, magnetic nanoparticles (MNPs) were electrostatically combined with chitosan-coated silver nanoparticles (Chi-Ag NPs) to synthesize the MNPs@Chi-Ag NPs nanocomposite. CoFe₂O₄ NPs were prepared as MNPs. The resulting nanocomposite, which demonstrated colloidal stability after optimization, was characterized using various techniques, including UV-VIS and FTIR spectroscopy, XRD, TEM, SEM, and DLS. As a SERS substrate, the MNP@Chi-Ag NPs exhibited considerable analytical enhancement factors of (1.5 ± 0.4) × 10⁶, (7.0 ± 0.3) × 10⁶, and (1.2 ± 0.5) × 10⁶ for the detection of water contaminants BCB, CV, and MP, respectively. It was demonstrated that the substrate enhances precision and exhibits preconcentration. Finally, the MNPs@Chi-Ag NP nanocomposite demonstrates remarkable antibacterial activity, with larger inhibition zones observed at higher nanocomposite concentrations, indicating a concentration-dependent effect. Full article

Offshore oil and gas exploitation is one of the riskiest businesses to invest in and is dominated by various uncertainties: high deepwater pressure, low temperatures, remote operation, long-distance tiebacks and transportation, as well as environmental factors such as wind, waves and ocean currents. Serving as a profitability threshold, the minimum economic field size is defined as the economic recoverable reserve level that an oilfield must exceed to achieve economic returns. This paper develops an approach for determining the minimum economic field size of offshore oil and gas reservoirs. It categorizes the capital expenditure into four major components: drilling and completion costs, platform costs, pipeline costs, and subsea production system costs. The regression models of drilling costs and subsea production costs are developed respectively, with water depth and recoverable reserves as key influencing factors. The pipeline costs are estimated using the unit pipeline cost per mile and pipeline length. A profit model for the offshore field is established under the constraints of the contract, which allocates the oilfield’s production profits between the contractor and the government according to the contractual fiscal terms. Finally, taking the Lucius oilfield in the Gulf of Mexico as a case study, the paper simulates its investment, operating costs, and oilfield revenues. The minimum economic field size is calculated, accompanied by the derivation of the sensitivity boundaries for the primary parameters. Full article

Soybean (Glycine max) is a vital food and oil crop in China, yet its yield and quality are severely threatened by piercing–sucking damage caused by Riptortus pedestris (Hemiptera: Alydidae) to soybean pods. Under global climate warming and expanded soybean cultivation, temperature has become a key environmental factor driving the spread of and aggravated damage caused by R. pedestris. We investigated the effects of temperature (32, 36, 40, 42, and 44 °C) and exposure duration (1–4 h) on the energy substances and antioxidant enzyme activities in adult R. pedestris. These two factors also had significant effects on the pest’s energy substances and antioxidant defense. Under short-term high-temperature stress, the water loss rate and fat, total sugar, and glycogen contents increased significantly, while protein content showed a fluctuating upward trend, with distinct sexual differences in these responses; the water loss and energy substance levels within the lethal high-temperature range, around 44 °C, were generally higher than those in the sublethal range (36–42 °C). R. pedestris showed physiological changes consistent with enhanced heat tolerance and adaptability, including water balance regulation, carbohydrate and lipid accumulation, and modulation of protein synthesis and degradation. In the sublethal high-temperature range, antioxidant enzyme activity patterns were altered, and SOD activity was increased; meanwhile, the MDA content also rose, and POD and CAT activities decreased. In the lethal high-temperature range, the overall antioxidant enzyme activities were lower than in the suitable temperature range, with the POD activities and MDA content still rising. These results suggest that the dynamic adjustment of antioxidant enzyme activities may contribute to alleviating oxidative damage and rapid adaptation to temperature-induced oxidative stress in R. pedestris. These findings indicate that R. pedestris possesses physiological plasticity to cope with sublethal heat stress through metabolic reallocation and antioxidant defense activation, but extreme temperatures cause severe physiological disruption. This study provides insights into the thermal biology and heat resistance mechanisms of this pest under climate warming scenarios. Full article

This study develops a ternary Fe-based geopolymer system composed of metakaolin (MK), red mud (RM), and fly ash (FA) for the preparation of sustainable water-retaining subgrade materials for sponge-city roadbed applications. Unlike conventional formulations primarily designed for structural strength or rapid permeability, the proposed MK–FA–RM system was designed to improve water-storage capacity while maintaining adequate mechanical support and environmental compatibility. In this ternary system, MK provides highly reactive aluminosilicate species for geopolymer network formation, RM introduces Fe-bearing phases and enhances industrial solid-waste utilization, and FA contributes to particle packing, workability, and resource efficiency. A constrained ternary mixture design implemented using Design-Expert software was adopted to optimize precursor proportions. Within the investigated compositional range, the fitted first-order mixture model showed acceptable statistical adequacy for preliminary composition screening (R² = 0.86). The optimal blend (60% MK, 30% RM, and 10% FA) achieved a 7-day compressive strength of 8.37 MPa and a water retention rate of 35.3% under ambient curing conditions, satisfying the strength requirement considered for the target subgrade/base-layer application. Microstructural and phase analyses suggest that the synergistic interaction of the three precursors promoted Fe-modified aluminosilicate gel formation together with conventional geopolymer gel products, while improving matrix continuity and preserving interconnected pore space for water storage. This multiscale structural effect helps explain how the material achieved a balance between water retention capacity and mechanical support. Under the tested conditions, the material maintained acceptable residual strength after short-term exposure to water, acid, and sulfate-containing solutions. Life-cycle assessment indicated a 70% reduction in CO₂ emissions compared with ordinary Portland cement, while pilot-scale cost analysis showed a 39% lower production cost than MetaMax-based geopolymer materials. Pilot-scale application further demonstrated the constructability and water-regulation potential of the material in practical environments. Overall, the proposed ternary Fe-based geopolymer demonstrates that Fe-rich industrial wastes can be engineered into low-carbon and economically viable water-retaining subgrade materials that balance hydraulic regulation, structural adequacy, and sustainability. Nevertheless, long-term durability, cyclic loading performance, and direct nanoscale characterization of Fe-bearing gel evolution still require further investigation. Full article

Traditional urban landscape evaluations have primarily relied on either objective spatial metrics, such as the Green View Index (GVI), or subjective human surveys, often failing to capture the complex mechanisms of human environmental perception. This study proposes a novel Explainable Artificial Intelligence (XAI) framework that integrates objective physical configuration with subjective cognitive assessment to predict human landscape preference. Utilizing 159 urban landscape images, we extracted physical features via semantic segmentation (SegFormer) and psychological perceptions via a zero-shot vision-language model (CLIP). Our hybrid Random Forest model successfully bridged these dimensions, achieving moderate yet promising predictive performance (Rsquare = 0.442). SHAP (Shapley Additive exPlanations) analysis revealed that psychological perceptions—specifically Safety (0.104), Fascination (0.096), and Tranquility (0.080)—outperformed traditional objective metrics like GVI (0.067) in determining overall preference, while sub-model interpretation linked these psychological responses to specific physical elements such as buildings, sky openness, low vegetation, and water bodies. The findings suggest that urban green space design should move beyond maximizing greenery quantity and instead prioritize spatial compositions that induce psychological security, visual interest, and restoration. The proposed framework offers a scalable and interpretable tool for human-centered landscape assessment, while acknowledging limitations related to sample size, cultural generalizability, pretrained model bias, and reliance on static two-dimensional imagery. Full article

Agroforestry and perennial tree crop production systems, particularly in Mediterranean regions, exhibit a high degree of integration among trees, herbaceous, and soil components. They provide essential services including provisioning, regulation, support, and cultural services, which enhance human health, well-being, and economic stability. However, guaranteeing their long-term resilience in the face of environmental challenges, including drought and soil degradation, is essential for the sustainable management of these systems. We examine the impact of microsite conditions (soil and herbaceous layer) and their management on olive trees (Olea europaea L.) under varying levels of drought stress. A fully factorial design was implemented in a Spanish agroforestry system, combining two irrigation regimes (rainfed vs. summer irrigation) and two soil management practices (customary plowing vs. herbaceous layer conservation) across four independent and replicated zones. Twelve olive trees per zone were individually monitored, treating each tree as the experimental unit, with one 50 × 50 cm sampling plot per tree in which microsite conditions were characterized for each tree. Plowed areas (shallow tillage) showed lower industrial extraction yield (%), fat yield based on dry matter (%), olive maturity and phytosanitary status compared to areas conserving their herbaceous layer cover (0.81, 0.96, 0.92, and 0.65-fold lower, respectively). Rainfed areas (i.e., those without supplemental water supply) showed a reduction in both industrial extraction yield (%), olive yield (kg tree⁻¹) and oil yield (kg ha⁻¹) (0.77, 0.86 and 0.67-fold lower, respectively). Under combined tillage and water-deficit conditions, oil yield (kg ha⁻¹), industrial extraction yield (%), and total phenolic content (ppm) were considerably lower (0.50, 0.60, and 0.67-fold lower, respectively). Furthermore, low quality of the herbaceous layer dominated by nitrophilous invasive species were associated with decreased leaf nutrient content, lower industrial extraction yield, reduced olive maturity and poorer phytosanitary status of olives. These findings suggest that maintaining a spontaneous herbaceous layer with a high-quality species (legume incorporation) and well-managed herbaceous cover, i.e., repeated mowing of the herbaceous layer instead of customary plowing, can enhance sustainable olive production by improving soil resilience, reducing water stress, and optimizing nutrient use, thereby supporting long-term ecosystem stability and agricultural productivity. Full article

Recycled aggregates (RAs) from construction and demolition waste (CDW) provide substantial circular-economy benefits, yet their elevated porosity, adhered mortar, and heterogeneity typically impair the mechanical performance and durability of recycled aggregate concrete (RAC). This PRISMA 2020-compliant systematic review synthesises 2180 records (2015–2026) to evaluate advanced strategies for enhancing RA quality prior to structural use. This paper critically compares removal-based treatments (mechanical, thermal, acid cleaning) with strengthening and densification approaches, including accelerated carbonation, pozzolanic and nano-silica coatings, polymer impregnation, microbial-induced calcium carbonate precipitation (MICP), and modified mixing methods such as triple-stage mixing (TSMA). Evidence shows that while all RA types (including recycled fine aggregate (RFA), recycled coarse aggregate (RCA), and their combination (RFCA)) can slightly reduce compressive strength and 30% replacement serves as a critical threshold, beyond this, strength loss accelerates, particularly in RCA and RFCA mixes. However, accelerated carbonation and TSMA consistently refine the interfacial transition zone, reduce water absorption by 17–30%, and recover 85–94% of natural aggregate concrete strength. Bio-deposition reduces water absorption by 13–21%, while acid/silica fume treatments improve late-age strength but carry environmental trade-offs. This review formulates a practice-oriented implementation framework for structural-grade RAC. Sustainability analyses indicate that carbonated RA can achieve net-positive CO₂ abatement when under low-carbon energy supply. A mechanistic schematic is presented to synthesise treatment-to-pore-structure/durability pathways across the four principal treatment routes, and a quantitative synthesis plot compares water absorption reductions across all treatment types using 13 data points drawn from included studies. A structured treatment comparison evaluates the energy intensity, industrial scalability, CO₂ footprint, and technology readiness level for each strategy. The remaining challenges include a lack of hybrid treatment studies, limited real-scale durability data, and insufficient mechanistic models linking treatment to pore structure evolution. This review recommends harmonised durability-based criteria and updates to standards (e.g., BS 8500, EN 12620) to support the scalable deployment of treated RA. Full article

A thorough understanding of the resistivity response characteristics of ethanol-contaminated soil is of great significance for the development of non-destructive geophysical detection techniques and for supporting contaminated site investigation and assessment. This experimental study aims to systematically investigate the resistivity behavior of ethanol-contaminated sandy soils, with a focus on the coupled mechanisms of multiple factors, including water content, ethanol concentration, particle size distribution, and contamination time. It is hypothesized that water content serves as the dominant factor controlling resistivity, whereas ethanol concentration and contamination time regulate resistivity by altering the physicochemical properties of the pore fluid. Under laboratory conditions, silt, fine sand, and medium sand were selected as the test materials. Resistivity was systematically measured using a Miller Soil Box with increasing water content, Wenner array configuration across varying water contents (3–24%), ethanol concentrations (40–98%), and contamination durations (0–144 h). The experimental results indicate the following: (1) Regardless of the presence of ethanol contamination, the resistivity of sandy soil decreases with increasing water content following a power-law relationship. The decrease is most pronounced at low water contents (3–9%), and gradually stabilizes at higher water contents. The results show that, at a constant water content, resistivity systematically and consistently follows the order: silt > medium sand > fine sand. (2) The influence of ethanol concentration on resistivity is constrained by water content levels, and the overall increase in resistivity is primarily attributed to ion dilution and the obstruction of conductive pathways. (3) Over time, resistivity exhibits a two-stage increasing trend, associated with ethanol volatilization and water loss. Resistivity changes in fine sand samples contaminated with ethanol at concentrations ranging from 75% to 95% follow a two-stage pattern. The initial phase of growth is characterized by a gradual increase over a period of 0–48 h, followed by a more rapid increase during the subsequent phase, which extends from 48 to 144 h. The results show that higher initial ethanol concentrations enhance the sensitivity of resistivity to temporal changes. Comprehensive analysis indicates that the resistivity variation mechanism under multi-factor coupling conditions can be summarized as follows: the water content is the dominant factor in the regulation of the conductive pathways; the particle size distribution determines pore structure and the characteristics of the particle interface; ethanol concentration and contamination time dynamically alter pore fluid properties, collectively regulating the resistivity response. Although the experiments were conducted under controlled laboratory conditions and the results have certain limitations, they provide a preliminary reference for interpreting resistivity responses in relatively homogeneous sandy contaminated sites and offer theoretical support for the application of resistivity methods in contamination identification and dynamic monitoring. Full article

Urban water scarcity and climate change pose significant challenges for sustainable development, particularly in rapidly expanding metropolitan areas. In cities like Casablanca, these pressures also threaten the preservation of cultural heritage sites such as traditional public bathhouses (Hammams). This study investigates how Hammams can integrate sustainable water management solutions in alignment with Sustainable Development Goal 11 (SDG 11), focusing on the treatment and reuse of graywater. This study compares three graywater treatment systems, a Membrane Bioreactor (MBR), a Sequencing Batch Reactor (SBR), and a Moving Bed Biofilm Reactor (MBBR), evaluated through literature review and dimensioning calculations, and also integrates an existing treatment plant in Berlin that functions as a real-scale laboratory. The comparison is based on a set of technical, economic, and environmental criteria used for comparative engineering design assessment and evaluation for the selected Hammam water reuse applications. All systems are technically feasible but show distinct trade-offs. The SBR has the lowest energy demand and highest cost savings, the MBBR offers a compact and simple design, and the MBR provides the highest effluent quality at a higher energy cost. Heat recovery provides a significant thermal energy recovery potential but is reported separately from the electrical energy demand of the treatment systems. Full article

This article examines the scientific basis for using humic acids for the chemical stabilization of mineralized water prior to reverse osmosis. The need to develop alternative approaches to water pretreatment is due to the limited effectiveness of traditional antiscale reagents at high mineralization, as well as their potential environmental risks and the likelihood of secondary contamination of water systems. The article focuses on the mechanisms of interaction between humic acids and Ca²⁺ and Mg²⁺ hardness ions, which are mediated by complexation with carboxyl and phenolic functional groups. It is demonstrated that humic stabilization differs from classical softening and demineralization in that it is aimed not at the complete removal of dissolved salts, but at reducing the activity of ions involved in the formation of carbonate deposits. The potential advantages of this approach for reducing the scale-forming potential of water, improving the stability of reverse osmosis membranes, and extending inter-flushing intervals are discussed. The technological limitations associated with residual organic load, possible membrane fouling, the need to control total organic carbon, color and stability of the filter medium, as well as a pilot test of the proposed approach are considered. Full article

Emerging technologies offer significant opportunities for sustainable rural development; however, their applications have not been systematically mapped across all dimensions of sustainability. This scoping review aims to identify, classify, and synthesize the literature on emerging technologies in rural development, structured around four pillars: economic, social, environmental, and governance. Eligible studies included English-language scientific articles published between 2015 and 2025 that propose solutions based on emerging technologies in rural contexts, identified in the Web of Science Core Collection database, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Data extracted from the 129 eligible articles were synthesized in thematic tables and comparatively analyzed for each pillar. Results indicate an accelerated growth in publications after 2020, with machine learning, deep learning, and the Internet of Things dominating applications such as precision agriculture, telemedicine, and water management. Critical gaps persist in biodiversity monitoring, climate adaptation, elderly care services, and rural circular economy, with the governance pillar remaining the least represented. This study proposes an integrated framework and a knowledge map to guide future research and public policies toward balanced and sustainable rural transformation. Full article

This study investigates the reuse of mussel shell waste as a secondary raw material in bio-cement mortars designed for the additive manufacturing of artificial reefs for marine habitat restoration. The novelty of the research lies in combining a high recycled shell content (60 wt.%), low-clinker cement, and two 3D-printing techniques: Extruded Material Systems (EMS) and Powder-Based Systems (PBS). Mechanical performance was evaluated through flexural and compressive tests after 7, 28, and 91 days under both air and freshwater curing conditions, while environmental impacts were assessed through Life Cycle Assessment (LCA). The LCA evaluated both the environmental performance of shell-based mixtures compared with conventional materials and the impacts associated with the investigated fabrication techniques. The best-performing bio-mixtures achieved compressive strengths up to 46.01 MPa and flexural strengths up to 9.91 MPa after freshwater curing, demonstrating the suitability of shell-based mortars for submerged applications. LCA results showed reduced impacts in land use and mineral resource depletion compared with conventional mixtures, despite slightly higher energy and water demands associated with shell pre-treatment. The results demonstrate the technical and environmental feasibility of integrating aquaculture waste into sustainable 3D-printed marine restoration solutions. Full article