Search Results (15,987)

In multi-phase tectonic activity areas, complex stratigraphic uplift-subsidence cycles lead to multi-phase, superimposed diagenesis. This obscures the mechanisms of reservoir property evolution and makes predicting diagenetic sweet spots difficult. This study investigates the low-permeability clastic reservoirs in the Mesozoic of the Tanhai area, Jiyang Depression. Integrating thin-section petrography, scanning electron microscopy (SEM), X-ray diffraction (XRD), high-pressure mercury injection, and burial history analysis, it reveals multi-phase diagenetic characteristics from a tectonic perspective and quantifies pore structure modification mechanisms. Results show the reservoirs underwent strong compaction and multi-phase carbonate-dominated cementation. Dissolution is further distinguished into meteoric water, organic acid, and volcanic material-related alkaline dissolution. Pore-throat evolution indicates that compaction and cementation shift pores towards micropores (<0.1 µm), while meteoric and alkaline dissolution enlarge mesopores (0.1–10 µm) crucial for permeability. Reservoir diagenesis is divided into five tectonic—diagenetic stages. A quantitative model identifies two diagenetic sweet spot types: (1) zones near unconformities intensely leached by meteoric water, and (2) relatively shallow intervals affected by alkaline dissolution related to volcanic rocks under deep burial. This study establishes a tectonic—diagenetic—pore structure framework. It provides a basis for predicting reservoir sweet spots in analogous multi-phase tectonic settings. Full article

Landfill leachate (LL) is a complex wastewater characterized by high concentrations of organic matter and heavy metals, posing significant challenges to conventional treatment technologies. Electrochemical methods, particularly electrocoagulation (ECG), have shown promise for LL treatment; however, issues related to operational optimization and electrode durability remain insufficiently addressed. In this study, a novel electrocoagulation-based approach is proposed that systematically integrates process optimization with an explicit assessment of iron electrode reusability, which is an aspect that has been rarely explored in previous ECG studies on LL. Key operational parameters—current density, pH, inter-electrode distance, electrode surface area, and electrode material—were optimized to enhance treatment performance. Optimal conditions were achieved using iron electrodes at a current density of 256 A/m², pH 8, an inter-electrode distance of 1 cm, and an effective electrode surface area of 19.5 cm²/L. Under these conditions, removal efficiencies of 100% for zinc, 94.9% for copper, and 54.5% for total organic carbon (TOC) were obtained, demonstrating effective simultaneous removal of inorganic and organic contaminants. The electrode reusability tests showed stable removal efficiencies over ten consecutive operational cycles, highlighting the potential for reduced operational costs and improved process sustainability. Additionally, the treated effluent exhibited reduced phytotoxicity, as evidenced by lower germination inhibition (GI), reduced root growth inhibition (RGI), and enhanced removal of humic substances. Overall, the results demonstrate that the proposed ECG approach is a robust, flexible, and environmentally sustainable solution for LL treatment, with clear advantages over conventional EC systems in terms of long-term performance and resource efficiency. Full article

Maxillofacial skeletal reconstruction presents significant challenges due to anatomical complexity, functional requirements, and aesthetic demands. Traditional materials such as titanium and autogenous bone grafts have limitations, prompting interest in Polyetheretherketone (PEEK), a versatile thermoplastic polymer with advantages like biocompatibility, radiolucency, and elasticity similar to human bone. This multi-year case series evaluates the clinical outcomes of PEEK implants used in 56 cases on 53 patients for maxillofacial reconstruction, primarily for trauma (44 patients) and deformity (9 patients). PEEK implants were applied to various facial regions including the orbit, zygoma, mandible, and maxilla. The majority of surgeries utilised virtual surgical planning. Patient-specific implants were fabricated using 3D imaging technologies, allowing customisation for optimal fit and functionality. The mean patient age was 37 years with a split of 37 to 16 females. Some complications were noted such as infection and paraesthesia. However, the majority of patients experienced positive outcomes. The findings support PEEK implants as a safe, effective, and adaptable material for maxillofacial surgery, with potential for further advancements in material properties and surgical technologies to improve long-term outcomes. Full article

As vital components of urban rail transit networks, subway stations are widely scattered across diverse urban districts, whose sustainability performance exerts a notable impact on the overall urban ecological and environmental quality. This study constructs a three-dimensional numerical model to conduct a comparative assessment of the seismic behavior of subway stations adopting different bearing systems at beam-column joints. The seismic responses of two typical structural configurations, a traditional rigid-jointed subway station and another equipped with rubber isolation bearings, are examined under a series of ground motions, with due consideration of amplitude scaling effects and material nonlinearity. A comprehensive evaluation is carried out on key performance parameters, including structural acceleration responses, column rotation angles, damage evolution processes, and internal force distributions. Based on this analysis, the research clarifies the sustainability implications by establishing quantitative correlations between seismic response indices (i.e., deformation extent, damage degree, and internal force magnitudes) and post-earthquake outcomes, such as repair complexity, material requirements, carbon emissions, and socioeconomic effects. The results can advance the integrated theory of seismic-resilient and sustainable design for underground infrastructure, providing evidence-based guidance for the optimization of future subway station construction projects. Full article

The integration of complex system concepts and sustainability in chemical engineering education is often limited to elective or separate courses rather than their integration into the core curriculum. This pedagogical gap can lead to graduates who lack a holistic understanding of the intricate interplay between industrial processes and the Earth’s ecological limits, and the feedback loops required to address complex global challenges. This paper presents a transformative approach to close this gap by embedding the Planetary Boundaries framework and system thinking across core chemical engineering courses, such as Material and Energy Balances, Reaction Engineering, and Process Design, and extending this integration to capstone projects. The framework treats the curriculum itself as an interconnected learning system in which key systems concepts are revisited and deepened through contextualized examples and digital modeling tools, including process simulators and life-cycle assessment. We map each boundary to illustrative process examples and learning activities and discuss practical implementation issues such as curriculum crowding, educator readiness, and data availability. This approach aligns with outcome-based education goals by making system thinking and absolute sustainability explicit learning outcomes, preparing future chemical engineers to design processes that respect planetary limits while balancing technical performance, economic feasibility, and societal needs. Full article

In severely saline-alkali soils, surface salt accumulation caused by intense water evaporation results in elevated salinity, low organic matter content, and suppressed microbial activity, collectively impairing plant physiological metabolism and growth. Superabsorbent polymers hold significant potential for ameliorating saline-alkali soils by regulating soil water–salt dynamics. Biochar, a carbon-rich organic material, plays a pivotal role in enhancing soil organic matter storage, whereas vermicompost, a microbiologically active organic amendment, contributes substantially to improving soil microbial functions. Therefore, this study developed a novel superabsorbent polymer reinforced with vermicompost and biochar (VB-SAP) and further investigated its effects on metabolic pathways associated with enhanced S. cannabina stress resistance in severely saline-alkali soils. The results showed that VB-SAPs significantly increased soil water and organic matter contents by 10.9% and 38.7% (p < 0.05), respectively, and decreased topsoil salinity of saline soils by 44.9% (p < 0.05). The application of VB-SAP altered the soil bacterial community structure and increased the complexity of the bacterial co-occurrence network, specifically enriching members of the phylum Pseudomonadota, which are widely recognized as common plant growth-promoting rhizobacteria. Moreover, VB-SAPs significantly upregulated root-associated salt tolerance genes involved in phenylpropanoid biosynthesis, tryptophan metabolism, and arginine–proline pathways, thereby enhancing root biomass accumulation, nutrient uptake, and shoot growth of S. cannabina. Collectively, these findings reveal that the new type of superabsorbent polymer reinforced with vermicompost and biochar may enhance the salt tolerance and growth of S. cannabina by reshaping the rhizosphere microenvironment, including reducing soil salinity, increasing soil water and organic matter contents, and promoting beneficial bacteria in severely saline-alkali soil, thereby providing novel strategies for the integrated improvement of saline soils. Full article

Ceramic matrix composites (CMCs) exhibit excellent high-temperature strength, oxidation resistance, and fracture toughness, making them superior to traditional metals and single-phase ceramics in extreme environments such as aerospace, nuclear energy equipment, and high-temperature protection systems. The mechanical properties of CMCs directly influence the reliability and service life of structures; thus, accurately predicting their mechanical response and service behavior has become a core issue in current research. However, the multi-phase heterogeneity of CMCs leads to highly complex stress distribution and deformation behavior in traditional mechanical property testing, resulting in significant uncertainty in the measurement of key mechanical parameters such as strength and modulus. Additionally, the high manufacturing cost and limited experimental data further constrain material design and performance evaluation based on experimental data. Therefore, the development of effective numerical simulation and mechanical modeling methods is crucial. This paper provides an overview of the research hotspots and future directions in the field of CMCs numerical simulation and mechanical modeling through bibliometric analysis using the CiteSpace software. The analysis reveals that China, the United States, and France are the leading research contributors in this field, with 422, 157, and 71 publications and 6170, 3796, and 2268 citations, respectively. At the institutional level, Nanjing University of Aeronautics and Astronautics (166 publications; 1700 citations), Northwestern Polytechnical University (72; 1282), and the Centre National de la Recherche Scientifique (CNRS) (49; 1657) lead in publication volume and/or citation influence. Current research hotspots focus on finite element modeling, continuum damage mechanics, multiscale modeling, and simulations of high-temperature service behavior. In recent years, emerging research frontiers such as interface debonding mechanism modeling, acoustic emission monitoring and damage correlation, multiphysics coupling simulations, and machine learning-driven predictive modeling reflect the shift in CMCs research, from traditional experimental mechanics and analytical methods to intelligent and predictive modeling. Full article

Cellular structures are well-established in biological materials and are often mimicked in many kinds of structural designs applicable to engineering. This results from their lightweight designs and good mechanical properties. Cellular designs in nature have extremely complex configurations. As a result, the deformation behaviour models for bioinspired hollow parts based on these geometries, that are presently available in the literature, are limited in their capacity to provide detailed descriptions of the mechanisms resulting in deformation. Extensions to the existing deformation behaviour mechanisms of cellular parts are proposed in this paper. First, a general outlook on cellular designs is given. This is followed by a review of the commonly recognised two-stage stress–strain curve for cellular parts and its comparison with the new curve suggested in this paper, which incorporates suggestions more fully accounting for the deformation mechanisms of these structures. Further, analytical models that are available in the literature, outlining the behaviour of cellular parts, are highlighted, together with new models developed here for predicting failure of lattice structures based on the Tresca and von Mises criterion. Next follows a discussion of proposed strategies that could be adopted in deformation behaviour models for optimising the design of hollow structures to improve their mechanical properties. Finally, the anticipated challenges for and future insights into the incorporation of the cellular behaviour models suggested here, in cutting-edge structural design for additive manufacturing (AM), are highlighted. Full article

The Hadamengou gold deposit, hosted in the Precambrian metamorphic basement, is a super-large gold deposit occurring along the northern margin of the North China Craton. Despite extensive investigation, the genesis of the gold mineralization is poorly understood and remains highly debated. This study integrates a comprehensive dataset, including fluid inclusion microthermometry and C-H-O-S-Pb isotopes, to better constrain the genesis and ore-forming mechanism of the deposit. Hydrothermal mineralization can be divided into pyrite–potassium feldspar–quartz (Stage I), quartz–gold–pyrite–molybdenite (Stage II), quartz–gold–polymetallic sulfide (Stage III), and quartz–carbonate stages (Stage IV). Four types of primary fluid inclusions are identified, including pure CO₂-type, composite CO₂-H₂O-type, aqueous-type, and solid-daughter mineral-bearing-type inclusions. Microthermometric and compositional data reveal that the fluids were mesothermal to hypothermal, H₂O-dominated, and CO₂-rich fluids containing significant N₂ and low-to-moderate salinity, indicative of a magmatic–hydrothermal origin. Fluid inclusion assemblages further imply that the ore-forming fluids underwent fluid immiscibility, causing CO₂ effusion and significant changes in physicochemical conditions that destabilized gold bisulfide complexes. The hydrogen–oxygen isotopic compositions, moreover, support a dominant magmatic water source, with increasing meteoric water input during later stages. The carbon–oxygen isotopes are also consistent with a magmatic carbon source. Sulfur and lead isotopes collectively imply that ore-forming materials were derived from a hybrid crust–mantle magmatic reservoir, with minor contribution from the country rocks. By synthesizing temporal–spatial relationships between magmatic activity and ore formation, and the regional tectonic evolution, we suggest that the Hadamengou is an intrusion-related magmatic–hydrothermal lode gold deposit. It is genetically associated with multi-stage magmatism induced by crust–mantle interaction, which developed within the extensional tectonic regimes. Full article

The separation of rare earth elements (REEs) with similar chemical properties remains a relevant challenge today, most often addressed using liquid–liquid and solid-phase extraction with various chelating agents. Excellent complexing agents for REEs are 1,3-diketones and their analogs. We have for the first time proposed a method for preparing a material consisting of a covalently immobilized 3-acyl-4-hydroxycoumarin ligand on silica. For its synthesis, we employed a strategy based on the “click” reaction of 3-azidopropyl silica with a propargyl-containing coumarin–chalcone conjugate—this approach is the most tolerant and does not affect the coordinationally active fragment of the ligand. The material was characterized by thermal analysis, IR spectroscopy, and ¹³C NMR. The potential of the synthesized material for REE preconcentration was demonstrated at pH 5–5.5: high extraction efficiency for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III) was observed, with fast adsorption kinetics (30 min) and extraction degrees of ~98%. Under unified conditions of static and dynamic extraction for Gd(III), Dy(III), Er(III), Eu(III), Sm(III), and Yb(III), affinity series toward the surface were obtained as a function of the distribution coefficient. It was shown that 10-fold molar excesses of Fe(III), Al(III), Cu(II), Ni(II), and Co(II) allow retention of more than 95% extraction for Dy(III) and Er(III). After adsorption of Dy(III) and Er(III), shifts in the carbonyl group absorption bands are visible in the IR spectra of the material, indicating a chelating mechanism of sorption. Additional studies are required for implementation in analytical and preparative REE separation schemes; however, preliminary data show that the material is a highly active adsorbent. Full article

Composite laminates possess complex anisotropic behavior, motivating the development of simplified yet accurate modeling approaches. In this paper, we present a study that introduces a stiffness-invariants-based constitutive model for symmetric, balanced composite laminates, highlighting a novel “quasi-Poisson’s ratio” parameter as a key innovation. The proposed method reconstructs the laminate stiffness matrices using invariant theory (trace of stiffness tensor) and a Master Ply concept, thereby reducing the number of independent material constants. The methods and assumptions (e.g., neglecting minor bending-twisting couplings) are outlined, and the model’s predictions of critical buckling loads are compared to classical laminate theory (CLT) results. Good agreement is observed in most cases, with a consistent conservative bias of CLT. The results confirm that the invariant-based model captures the dominant stiffness characteristics of the laminates and can slightly overestimate stability margins due to its idealizations. In conclusion, this work provides an efficient constitutive modeling framework that can be integrated with finite element analysis and extended to more general laminates in future studies. Full article

Circulation is one of the most prevalent and severe complications during the drilling and completion of deep and ultra-deep wells, especially in fractured and karstic formations. In regions such as the Sichuan Basin, bottom-hole temperatures exceeding 200 °C, limited formation strength, and frequent lithological alternations significantly reduce the effectiveness of conventional granular materials under high-temperature and long open-hole conditions. Bridging-type plugging systems based on particle gradation or principles often exhibit low success rates due to fiber softening, rubber aging, and erosion-induced deterioration of the sealing structure. In this study, a high-temperature-resistant bridging composite system was developed to meet the extreme conditions in deep and ultra-deep wells. By incorporating temperature-resistant bridging particles and flexible reinforcing components, the slurry establishes a synergistic “bridging–filling–densification” sealing mechanism. Meanwhile, the combined use of retarders, fluid-loss reducers, and rheology modifiers ensures stable pumpability and adequate curing densification at 200 °C. Overall, the results provide new insights and experimental evidence for the design of high-temperature cement-based plugging materials, offering a promising approach for improving loss-control effectiveness and wellbore strengthening in complex intervals. Full article

Accurate brightness temperature (TB) measurements and microwave emissivity retrieval in passive microwave sensing conventionally rely on absolute radiometric calibration, which often requires additional hardware and complex procedures. Under well-defined geometric and environmental conditions, this study proposes a mirror-reflection-based method for measuring the microwave emissivity of flat scenes using ground-based radiometers without conventional absolute calibration. The method employs a simplified four-step observation sequence, in which the radiometer measures the pure flat scene, the flat scene with mirror reflection, the reference wall, and the cold sky. A geometric model is developed to determine the effective incidence-angle range, and an analytical framework is developed to evaluate retrieval accuracy. Numerical simulations are conducted to examine the effects of scene material, reference-wall property, operating frequency, polarization, and radiometric sensitivity. Outdoor experiments are further performed to assess feasibility under practical measurement conditions. The results show that, within moderate incidence-angle ranges and under stable radiometric conditions, the retrieved emissivities of flat scenes agree well with theoretical predictions. These findings indicate that the proposed mirror-reflection-based approach provides a feasible supplementary or alternative solution for emissivity estimation of flat targets in ground-based measurements when absolute calibration is unavailable or impractical, rather than a replacement for conventional calibration techniques. Full article

To address the impact of environmental and equipment factors on signal identification in highway tunnel drainage pipeline blockage monitoring, this study aims to elucidate the influence patterns of pipeline flow rate, optical fiber deployment scheme, and fiber performance on blockage-induced acoustic signals. A full-scale concrete pipeline experimental platform was established. Data were acquired using a HIFI-DAS V2 sensing system. The time–frequency domain characteristics of acoustic signals under different flow rates (50 m³/h and 100 m³/h), fiber deployment schemes (inside the pipe, outside the pipe, and outside a soundproofing layer), and fiber materials (six typical types) were analyzed and compared. The degree of influence of each factor on signal amplitude and dominant frequency components was quantified. The experimental results indicate that: Compared to a flow rate of 50 m³/h, the amplitude characteristic value at the blockage channel exhibited a marked increase at 100 m³/h, accompanied by an increase in the number and amplitude of dominant frequency components. While the dominant frequency components of the acoustic signals were less stable across the three deployment schemes, the overall amplitude at the blockage channel was consistently higher than that at non-blockage channels. When the fiber was deployed farther from the fluid core (outside the soundproofing layer), the dominant frequencies essentially disappeared, with energy distributed in a broadband form. The peak amplitude and array energy of the sensitive vibration sensing fiber were 2 times and 3.6 times those of the worst-performing type, respectively. Furthermore, its physical properties are better suited to the tunnel environment, effectively enhancing signal acquisition stability and the signal-to-noise ratio. Comprehensive analysis demonstrates that deploying sensitive fibers inside the pipe is more conducive to the accurate identification of blockage events. Moreover, uniform dominant frequency components and threshold criteria are not recommended along the entire length of the drainage pipe. This research provides theoretical and experimental support for parameter optimization of DAS systems to achieve high-precision pipeline blockage monitoring in complex tunnel environments. Full article

The viscoelastic properties of ultraviolet radiation-curable polymer coatings of optical fibers were studied experimentally and numerically. The test setup was completed, and a series of natural experiments were conducted for an extended temperature range from −110 °C to +120 °C using a dynamic mechanical analyzer (DMA). Discrete dependencies of the complex modulus on temperature and frequency of kinematic loading were obtained. The problem of multiparametric optimization was solved. Defining relations were obtained for protective coating polymers, making it possible to describe the thermomechanical behavior of the glass-forming materials under consideration in a wide temperature range, including relaxation transition. The optimal solution was found for 18 series terms at the selected reference temperature T_r = −70 °C, C₁ = 20.036, and C₂ = 32.666 for the DeSolite 3471-1-152A material. The optimal solution was found for 60 series terms at the selected reference temperature T_r = 0 °C, C₁ = 40,242.2827, and C₂ = 267,448.888 for the DeSolite DS-2015 material. The models were verified according to the data of creep experiments. The capabilities of the viscoelastic model were demonstrated by the example of a numerical experiment on free thermal heating/cooling of a Panda-type optical fiber. Full article