Search Results (137)

Although coagulation can enhance sludge dewatering performance, it often leads to dense flocs, hindered water release, and secondary pollution of the sludge cake. In this study, three types of biochar-based skeleton materials, tea waste-derived biochar (TB), PAC sludge-derived biochar (PB), and their mixture (MB), were employed in combination with polyaluminum chloride (PAC) to improve sludge permeability and water release capacity. The results showed that PAC alone reduced the water content (Wc) and capillary suction time (CST) of raw sludge (RS) from 79.07% and 97.45 s to 69.45% and 42.30 s, respectively. In contrast, biochar–PAC composite conditioning achieved further enhancement. Among them, the TBP group (10% DS TB + 4% DS PAC) exhibited the best performance, with Wc and CST reduced to 58.73% and 55.65 s, reaching the threshold for deep dewatering (Wc < 60%). Low-field nuclear magnetic resonance (LF-NMR) analysis revealed an enhanced transformation from bound to free water, improving water mobility. Zeta potential and particle size analysis indicated that biochar promoted electrostatic neutralization and adsorption bridging. Rheological and EPS measurements demonstrated significant reductions in yield stress and apparent viscosity, alongside the enhanced release of proteins and polysaccharides into soluble EPS (S-EPS). Scanning electron microscopy and pore structure analysis further confirmed that biochar formed a stable porous skeleton (pore diameter up to 1.365 μm), improving sludge cake permeability. In summary, biochar synergizes with PAC through a “skeleton support–charge neutralization–adsorption bridging” mechanism, reconstructing sludge microstructure and significantly improving deep dewatering performance. Full article

With the continuous increase in mining activities, effective tailings management has become a critical concern in geotechnical and environmental engineering. This study systematically investigates the microstructural characteristics and 3D reconstruction behavior of copper tailings with different particle sizes using X-ray computed tomography (micro-CT), digital image processing, and 3D modeling techniques. Two particle size groups (fine: 0.075–0.15 mm; coarse: 0.15–0.3 mm) were analyzed to quantify differences in particle morphology, pore structure, and orientation anisotropy. Binary images and reconstructed models revealed that coarse particles tend to have more irregular and angular shapes, while fine particles exhibit more complex pore networks with higher fractal dimensions. The apparent porosity derived from CT data was consistently lower than laboratory measurements, likely due to internal agglomeration effects. Orientation analysis indicated that particle alignment and anisotropy vary systematically with section angle relative to the principal stress direction. These findings offer new insights into the particle-scale mechanisms affecting the packing, porosity, and anisotropy of tailings, providing a scientific basis for enhancing the structural evaluation and sustainable management of tailings storage facilities. Full article

Current research on foamed lightweight soil primarily focuses on mechanical properties and durability, with few studies addressing its hydraulic characteristics and internal pore structure in road reconstruction applications. However, the material’s high porosity and low bulk density may significantly alter its mechanical properties and durability under prolonged rainwater exposure, highlighting the importance of investigating its hydraulic characteristics and internal foam structure. Based on the analysis of water absorption and bulk density in phosphogypsum-based foamed lightweight soil, this study further discusses the material’s softening coefficient and internal pore structure through systematic data comparison. Experimental results demonstrate that the unconfined compressive strength (UCS) of both dry and water-soaked specimens increases linearly with dry density. Notably, soaked specimens with 0.5 g/cm³ dry density achieve compliant 7-day UCS values while displaying a steeper strength increase compared to dry specimens. A dry density of 0.64 g/cm³ ensures a softening coefficient exceeding 0.75, confirming the material’s suitability for humid environments. The material contains predominantly small pores (90% ≤ 0.2 mm diameter), with improved bubble distribution at the edges and higher upper porosity. Spherical pores (roundness 0.5–1) enhance mechanical properties, while phosphogypsum (optimal 10% dosage) effectively improves both strength and workability but requires corrosion control due to its hydration products. Full article

The global burden of cancer continues to grow, with bone cancer—though rare—posing serious challenges in terms of treatment and post-surgical reconstruction. Autologous bone grafting remains the gold standard, yet limitations such as donor site morbidity drive the search for alternative solutions. Tissue engineering, combining biomaterials and therapeutic agents, offers promising avenues. This study focuses on the development of multifunctional scaffolds based on collagen and hydroxyapatite obtained by the freeze-drying technique and incorporating both synthetic (doxorubicin) and natural (caffeic acid) compounds for osteosarcoma treatment. These scaffolds aim to combine tumor inhibition with bone regeneration, addressing the dual need for local drug delivery and structural repair in bone cancer therapy. The characterization of these composite materials revealed that a spongious structure with interconnected pores and a homogeneous pore distribution, with pore sizes between 20 and 250 μm suitable for osteoblasts infiltration. The Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis-differential scanning calorimetry (TG-DSC) and X-ray diffraction (XRD) analyses confirmed the formation of hydroxyapatite inside the collagen matrix. LDH and XTT assays confirmed that the antitumoral scaffolds possess great potential for osteosarcoma treatment, showing that after 3 days of culturing, the extracts containing doxorubicin-7A, both alone and in combination with caffeic acid-9A, significantly reduced the viability of cell lines to below 7% and 20%, respectively. Full article

Digital core refers to the use of three-dimensional physical imaging equipment and mathematical modeling to image the internal microstructure of a core and the use of computers to study the connectivity and pore distribution of the core microstructure. The digital core has emerged as a prominent research avenue in image processing in recent years. A three-dimensional (3D) image can be used to effectively study the microstructure and physical properties of a core. Three-dimensional reconstruction from two-dimensional core images is a crucial advancement in this field. Deep learning is advantageous in image reconstruction. However, when the traditional generative adversarial network (GAN) reconstruction method is adapted for reconstructing gray-scale core images, maintaining texture characteristics is difficult; additionally, it may produce blur artifacts in the GAN-generated gray-scale images. In this study, the physics statistical descriptor-informed deep image structure and texture similarity (PSDI-DISTS) metric, a higher-level metric than the traditional correlation function, is used as the loss function of the network, and a texture feature-constrained GAN (TFCGAN) model is proposed for reconstructing gray-scale core images. In addition, a balanced training strategy integrating L₁ and PSDI-DISTS losses is designed to optimize the model performance. The experimental results and seepage simulation analysis showed that TFCGAN can maintain the textural characteristics in the gray-scale core image reconstruction results. Furthermore, the reconstruction results exhibited seepage characteristics similar to those of the target. Full article

In recent years, in situ blasting–leaching, in the stope has emerged as an economically viable and environmentally sustainable mining technique for low-grade ore deposits. While the leaching efficiency is influenced by factors such as ore type, solution composition, and spraying speed, the most significant factor is the effect of post-blasting crushed-stone particle size and gradation on the pore structure, which subsequently influences seepage and leaching performance. To investigate how particle size and gradation affect the pore structure of granular media, physical models of ore particles with varying sizes and gradations were constructed. These models were scanned and three-dimensionally reconstructed using CT scanning technology and Avizo software (Avizo, Version 2023.1; Thermo Fisher Scientific: Waltham, MA, USA, 2023) enabling quantitative analysis of pore structure parameters. The results indicate that the coefficient of uniformity (Cu) is approximately negatively correlated with porosity, while the vertical absolute permeability (kz) follows an attenuated exponential trend. When the fine-particle content (L8 > L3 > L1) increases by 1.5-fold and 9-fold, the number of pore throats increases by 8.71% and 30.91%, respectively, the average pore size decreases by 75.1% and 64.4%, the average throat size decreases by 66.3% and 60%, and the connectivity rate decreases by 92% and 77.8%. This study further evaluates permeability based on the aforementioned pore structure parameters. Multiple regression analysis reveals that the connectivity rate and throat size have the most significant influence on permeability. Accordingly, permeability analysis and prediction are conducted using the improved Purcell formula, which demonstrates a strong correlation with the experimentally measured results. Full article

Consumer interest in vegetarian, ethical, and clean-label foods is reviving the use of plant-derived milk coagulants. Cardosins from Cynara cardunculus (“thistle”) are aspartic proteases with strong clotting activity, yet their technological impact in cheese remains under-explored. This study compared a commercial thistle extract (PC) with traditional bovine rennet rich in chymosin (AC) during manufacture and 60-day ripening of Caciotta cheese. Classical compositional assays (ripening index, texture profile, color, solubility) were integrated with scanning electron microscopy, three-dimensional surface reconstruction, and descriptive sensory analysis. AC cheeses displayed slower but sustained proteolysis, yielding a higher and more linear ripening index, softer body, greater solubility, and brighter, more yellow appearance. Imaging revealed a continuous protein matrix with uniformly distributed, larger pores, consistent with a dairy-like sensory profile dominated by milky and umami notes. Conversely, PC cheeses underwent rapid early proteolysis that plateaued, producing firmer, chewier curds with lower solubility and darker color. Micrographs showed a fragmented matrix with smaller, heterogeneous pores; sensory evaluation highlighted vegetal, bitter, and astringent attributes. The data demonstrate that thistle coagulant can successfully replace animal rennet but generates cheeses with distinct structural and sensory fingerprints. The optimization of process parameters is therefore required when targeting specific product styles. Full article

The synergistic development of low-permeability reservoirs such as deep coalbed methane (CBM) and tight gas has emerged as a key technology to reduce development costs, enhance single-well productivity, and improve gas recovery. However, due to fundamental differences between coal seams and tight sandstones in their pore structure, permeability, water saturation, and pressure sensitivity, significant variations exist in their flow capacities and fluid production behaviors. To address the challenges of production allocation and main reservoir identification in the co-development of CBM and tight gas within deep gas-bearing basins, this study employs the transient multiphase flow simulation software OLGA to construct a representative dual-gas co-production well model. The regulatory mechanisms of the gas–liquid distribution, deliquification efficiency, and interlayer interference under two typical vertical stacking relationships—“coal over sand” and “sand over coal”—are systematically analyzed with respect to different tubing setting depths. A high-precision dynamic production allocation method is proposed, which couples the wellbore structure with real-time monitoring parameters. The results demonstrate that positioning the tubing near the bottom of both reservoirs significantly enhances the deliquification efficiency and bottomhole pressure differential, reduces the liquid holdup in the wellbore, and improves the synergistic productivity of the dual-reservoirs, achieving optimal drainage and production performance. Building upon this, a physically constrained model integrating real-time monitoring data—such as the gas and liquid production from tubing and casing, wellhead pressures, and other parameters—is established. Specifically, the model is built upon fundamental physical constraints, including mass conservation and the pressure equilibrium, to logically model the flow paths and phase distribution behaviors of the gas–liquid two-phase flow. This enables the accurate derivation of the respective contributions of each reservoir interval and dynamic production allocation without the need for downhole logging. Validation results show that the proposed method reliably reconstructs reservoir contribution rates under various operational conditions and wellbore configurations. Through a comparison of calculated and simulated results, the maximum relative error occurs during abrupt changes in the production capacity, approximately 6.37%, while for most time periods, the error remains within 1%, with an average error of 0.49% throughout the process. These results substantially improve the timeliness and accuracy of the reservoir identification. This study offers a novel approach for the co-optimization of complex multi-reservoir gas fields, enriching the theoretical framework of dual-gas co-production and providing technically adaptive solutions and engineering guidance for multilayer unconventional gas exploitation. Full article

The influence of porosity on rock mechanical properties constitutes a critical research focus. This investigation explores the relationship between pore structure parameters and mechanical characteristics through reconstructed numerical models. The study employs an integrated approach combining laboratory experiments and numerical simulations. Initially, high-resolution X-ray computed tomography (CT) was utilized to capture three-dimensional geometric features of Sichuan white sandstone microstructures, complemented by mechanical parameter acquisition through standardized testing protocols. The research workflow incorporated advanced image processing techniques, including adaptive total variation denoising algorithms for CT image enhancement and deep learning-based threshold segmentation for feature extraction. Subsequently, pore structure reconstruction models with controlled porosity variations were developed for systematic numerical experimentation. Key findings reveal a pronounced degradation trend in both mechanical strength and elastic modulus with increasing porosity levels. Based on simulation data, two empirical models were established: a porosity–compressive strength correlation model and a porosity–elastic modulus relationship model. These quantitative formulations provide theoretical support for understanding the porosity-dependent mechanical behavior in rock mechanics. The methodological framework and results presented in this study offer valuable insights for geological engineering applications and petrophysical characteristic analysis. Full article

Drying constitutes an essential step in aerogel fabrication, where the drying method directly determines the pore structure and consequently influences the material’s functionality. This study employed various drying techniques to prepare balsa-wood-derived aerogels, systematically investigating their effects on microstructure, density, and performance characteristics. The results demonstrate that different drying methods regulate aerogels through distinct pore structure modifications. Supercritical CO₂ drying optimally preserves the native wood microstructure, yielding aerogels with superior thermal insulation performance. Freeze-drying induces the formation of ice crystals, which reconstructs the microstructure, resulting in aerogels with minimal density, significantly enhanced permeability, and exceptional cyclic water absorption capacity. Vacuum drying, oven drying, and natural drying all lead to significant deformation of the aerogel pore structure. Among them, oven drying increases the pore quantity of aerogels through volumetric contraction, thereby achieving the highest specific surface area. However, aerogels prepared by air drying have the highest density and the poorest thermal insulation performance. This study demonstrates that precise control of liquid surface tension during drying can effectively regulate both the pore architecture and functional performance of wood-derived aerogels. The findings offer fundamental insights into tailoring aerogel properties through optimized drying processes, providing valuable guidance for material design and application development. Full article

The Sichuan Basin is a key area for shale gas energy exploration in China. However, the pore evolution mechanism and accumulation effect of the Lower Jurassic continental shale gas in the northeastern Sichuan Basin remain poorly understood. In this study, the pore structure characteristics of shale reservoirs and the dynamic accumulation and evolution of shale gas in the northern Fuling and Yuanba areas were systematically analyzed by adsorption experiments, high-pressure mercury injection joint measurement, and thermal simulation experiments. The results indicate the following: (1) The continental shale in the study area is predominantly composed of mesopores (10–50 nm), which account for approximately 55.21% of the total pore volume, followed by macropores (5–50 μm) contributing around 35.15%. Micropores exhibit the lowest proportion, typically less than 10%. Soluble minerals such as clay minerals and calcite significantly promote pore development, while soluble organic matter may block small pores during hydrocarbon generation, which facilitates the enrichment of free gas. (2) The thermal simulation experiment reveals that pore evolution can be divided into two distinct stages. Prior to 450 °C, hydrocarbon generation leads to a reduction in pore volume due to the compaction and transformation of organic matter. After 450 °C, organic matter undergoes cracking processes accompanied by the formation of shrinkage fractures, resulting in the development of new macropores and a significant increase in pore volume. This indicates that thermal energy input during the thermal evolution stage plays a key role in reservoir reconstruction. (3) The early Jurassic sedimentary environment controls the enrichment of organic matter, and the Cretaceous is the key period of hydrocarbon accumulation. Hydrocarbon generation and diagenesis synergistically promote the formation of gas reservoirs. The Cenozoic tectonic activity adjusted the distribution of gas reservoirs, and finally formed the enrichment model with the core of source–reservoir–preservation dynamic matching. For the first time, combined with dynamic thermal simulation experiments, this study clarifies the stage characteristics of pore evolution of continental shale and identifies the main controlling factors of shale gas accumulation in the Lower Jurassic in northeastern Sichuan, which provides a theoretical basis for continental shale gas exploration and energy resource development, offering important guidance for optimizing the selection of exploration target areas. Full article

The paper presents a case study on the impact of a shallow landslide in overconsolidated clays, which was triggered during the winter of 2004–2005 due to exceptionally high pore pressures, on the operativity and serviceability of a key road artery in Sicily. During the period from 2004 to 2021, the landslide experienced several reactivations, particularly during the winter months when increased rainfall led to rising pore water pressures. These recurrent events resulted in temporary road closures and continuous restoration efforts, causing significant inconvenience for local communities and substantial economic losses for commercial, tourism, and agricultural activities in the area. In 2018, a comprehensive study was launched to reconstruct the detailed geotechnical model of the landslide, analysing its mechanical and kinematic characteristics, pore pressure regime, the depth and geometry of the sliding surface, and the causes of the landslide. The study indicates that the primary causes of both the initial landslide and its subsequent reactivations were the poor mechanical properties of the involved soils and seasonal fluctuations in pore water pressures. To ensure long-term stabilisation, the most suitable interventions were identified as the permanent reduction of pore pressures through the installation of drainage trenches and the construction of a road embankment using gabions, which also serve as drainage structures. These measures are highly effective, relatively cost-efficient, easy to implement, and environmentally sustainable. Full article

The transient electromagnetic (TEM) method is a widely used geophysical technique for detecting subsurface electrical structures. However, its inversion results are typically limited to resistivity parameters, making it challenging to directly infer key petrophysical properties, such as water saturation and porosity. This study proposes a petrophysics parameter inversion approach based on TEM data. By constructing multiple geoelectric models with varying porosities and water saturation values for numerical simulations, the results demonstrated that both the forward and inversion responses of the TEM field maintained errors within 5%. The inversion procedure begins with the reconstruction of the subsurface resistivity distribution, which reliably reflects the true geoelectric model. Based on the inverted resistivity, the water saturation and porosity parameters are subsequently estimated. The inversion results closely match the overall trend of the actual model and exhibit a clear response at the target layer. Finally, the proposed method is applied to a field test at the Tongxin Coal Mine. By integrating subsurface electrical responses with geological data, the spatial distributions of water saturation and porosity within the coal-bearing strata were delineated. This provides a scientific basis for the detailed characterization of the physical properties of coal and surrounding rock, as well as for understanding the development of pores and fractures in underground strata. Full article

A numerical experimental method combining the discrete element method (DEM) and the finite element method (FEM) is proposed to analyze water channel flow in heterogeneous porous media such as landfill layers. In this study, non-spherical particles —thin plates and rods—are introduced into DEM-FEM coupling for the first time, which allows for the virtual reconstruction of complex pore structures beyond the capability of traditional experimental approaches, such as soil tanks or X-ray CT. Fluid flow simulations performed on three types of virtual porous media showed that only the case with non-spherical particles generated water channels. Tortuosity analysis was used to quantify the complexity of the flow paths and showed median values of 1.258 and 1.218 for homogeneous and particle size-distributed cases, respectively. In contrast, the case simulating waste media had a significantly lower median tortuosity of 1.051, with a skewed distribution toward shorter paths, indicating dominant water channels. This shift in tortuosity, coupled with higher variance, serves as quantitative evidence of water channel formation. The results demonstrate that tortuosity analysis complements streamline visualization and provides a reliable means to detect and compare water channel flow behavior. The proposed DEM-FEM framework enables both qualitative and quantitative understanding of flow dynamics in large-scale, highly heterogeneous porous systems and is expected to support further research and practical design in landfill and drainage engineering. Full article

Accurate segmentation of soil pore structure is crucial for studying soil water migration, nutrient cycling, and gas exchange. However, the low-contrast and high-noise CT images in complex soil environments cause the traditional segmentation methods to have obvious deficiencies in accuracy and robustness. This paper proposes a hybrid model combining a Multi-Modal Low-Frequency Reconstruction algorithm (MMLFR) and UNet (MMLFR-UNet). MMLFR enhances the key feature expression by extracting the image low-frequency signals and suppressing the noise interference through the multi-scale spectral decomposition, whereas UNet excels in the segmentation detail restoration and complexity boundary processing by virtue of its coding-decoding structure and the hopping connection mechanism. In this paper, an undisturbed soil column was collected in Hainan Province, China, which was classified as Ferralsols (FAO/UNESCO), and CT scans were utilized to acquire high-resolution images and generate high-quality datasets suitable for deep learning through preprocessing operations such as fixed-layer sampling, cropping, and enhancement. The results show that MMLFR-UNet outperforms UNet and traditional methods (e.g., Otsu and Fuzzy C-Means (FCM)) in terms of Intersection over Union (IoU), Dice Similarity Coefficients (DSC), Pixel Accuracy (PA), and boundary similarity. Notably, this model exhibits exceptional robustness and precision in segmentation tasks involving complex pore structures and low-contrast images. Full article