Search Results (9,367)

Drying in granular porous media is governed by coupled thermal and hydraulic processes that can be substantially modified by biological activity. This proof-of-concept study investigated how surface heating and fungal colonization influence the evolution of thermal conductivity (λ) and matric suction (ψ) as functions of volumetric water content ${\theta }_v$ in Ottawa 20/30 sand. Four treatments were examined: sterile sand at 22 °C (T1), sterile sand at 28 °C (T2), fungal-amended sand with 10% biomass and 9-day incubation (T3), and fungal-amended sand with 15% biomass and 30-day incubation (T4). Samples were instrumented to monitor ${\theta }_v$, λ, and ψ during controlled evaporation using synchronized HYPROP and VARIOS measurements on the same specimen. Across all treatments, λ increased with ${\theta }_v$ (that is, λ declined as drying progressed), and ψ reflected the transition from hydraulically connected to disconnected pore water. Heating shortened the drying time but did not materially change the form of the λ–${\theta }_v$ relationship or generate strong matric gradients in sterile sand. Low biomass (T3) produced thermal and hydraulic responses comparable to the heated sterile control (T2), indicating limited pore-scale modification at early colonization. In contrast, high biomass (T4) widened the effective saturation range, maintained low and nearly uniform ψ across depth, and exhibited the steepest mid-range λ–${\theta }_v$ slope with a higher peak λ (~4 Wm⁻¹K⁻¹), consistent with hyphae and extracellular polymers stabilizing thin water films. A soil water retention curve (SWRC) analysis using the van Genuchten model further indicated increased water retention and delayed air entry with an increasing fungal biomass, with approximate air-entry values increasing from ~1.8 kPa (T3) to ~3.0 kPa (T4). Tests were terminated upon tensiometer cavitation rather than complete gravimetric dryness, constraining observations at very low ${\theta }_v$. These results indicate that heating primarily affects the rate of drying, whereas fungal networks alter the pathway by preserving hydraulic and thermal continuity at relatively high ${\theta }_v$. This behavior suggests a potential role of bio-mediated structuring in influencing near-surface thermo-hydraulic processes relevant to energy foundations, soil covers, and desiccation management in biologically active or bio-engineered soils. Full article

This study is a systematical investigation of the fundamental geological conditions for shale gas in the Wufeng–Longmaxi formations in western Hubei, China, using drilling core data, with Well Xiandi-2 serving as the key well for core observation and experimental testing, integrated with outcrop profiles and regional provincial-level shale gas block data. The analysis encompasses petrology, organic geochemistry, mineral composition, physical properties, pore types, and gas content. Through a comprehensive comparison with established shale gas production fields in the Sichuan Basin, the shale gas resource potential of the study area is evaluated, and favorable zones for shale gas exploration are delineated. The results indicate that the study area contains a continuous organic-rich shale interval with a 18.84 m net thickness, 2.3% average total organic carbon, 65–89% brittle mineral content, 2.36% average porosity, and thermal maturity within the gas window. Systematic comparison with the Jiaoshiba and Changning fields confirms comparable geological attributes, including organic matter abundance, reservoir porosity, and brittle mineralogy. Given this comparability, areas with burial depths shallower than 1500 m on the northwestern margin of the Xuefeng Uplift are interpreted to retain moderate shale gas resource potential. Three favorable zones are delineated as priority targets: the synclines on both sides of the Longtan normal fault and the Lianghekou Syncline. These findings provide practical exploration value: the identified favorable zones offer immediate drilling targets, the analytical workflow is transferable to other structurally complex blocks on the basin margin, and the potential of shallow-buried sequences expands exploration beyond the core Sichuan Basin into previously overlooked transitional zones. Full article

Pore structure characterization is crucial for understanding fluid flow in porous media, including oil and gas reservoirs, aquifers, and geologic formations. Carbonate formations, prevalent in oil and gas reservoirs, pose challenges due to their complex pore structure. This review summarizes diverse methods reported in the literature to characterize the pore structure of carbonate formations. Emphasizing the need for multiple methods and scales, the paper discusses pore-throat classification, imaging techniques (X-ray CT, SEM, and NMR), and pore network modeling. These methods help identify typical pore-throat types and structural features, which commonly exhibit irregular shapes and poor connectivity, thus influencing fluid flow behavior. Pore network modeling elucidates structural heterogeneity and its impact on fluid flow. These insights are vital for oil and gas production and groundwater management, providing a comprehensive understanding of fluid flow in porous media. Full article

Current challenges in the construction field emphasize the need for compatible and durable materials for heritage interventions. Traditional lime-based mortars often exhibit limitations under environmental exposure, particularly in terms of water absorption and freeze–thaw resistance. This article investigates the performance of hydroxyapatite (HAp)-modified lime mortars applied in a real-scale heritage context, namely a student built micro-museum developed within the Apoș Architecture Summer School. Following the premature degradation of a conventional lime mortar layer applied at roof level, HAp-modified formulations were introduced as a protective and consolidating solution. The experimental approach combines laboratory testing and in situ evaluation, including compressive strength measurements, water absorption, capillarity tests, chromatic analysis, and freeze–thaw assessment. The results indicate a reduction in water absorption from approximately 22% to 12%, an increase in compressive strength from 6.57 MPa to 19.95 MPa and a significant improvement in freeze–thaw resistance, reflected by a decrease in gelivity from 61.2% to 5.73%, compared to traditional lime mortars. In addition, the contact angle increased from 36° to 82°, indicating enhanced hydrophobic behavior. These improvements are associated with pore structure refinement, reduced capillary uptake, and enhanced interfacial bonding within the mortar matrix. The study also highlights the role of real-scale educational environments in validating sustainable material solutions. Full article

Magnetic polymeric microspheres are pivotal solid-phase carriers in chemiluminescence enzyme immunoassays (CLEIA). However, their practical clinical application is frequently hindered by non-specific adsorption, irreversible aggregation, and the intrinsic susceptibility of exposed outermost Fe₃O₄ nanoparticles to oxidation. To overcome these critical bottlenecks, we rationally engineered highly original monodisperse P(St-MMA)@Fe₃O₄@P(St-MMA) sandwich-structured microspheres. The bespoke amphiphilic outer shell acts as an impenetrable shield against hydration and oxidation, while maintaining a topologically size-matched mesoporous network (average pore size of 13.11 nm) for optimal antibody anchoring. Strikingly, this architecture ensures exceptional long-term colloidal stability, completely preventing macroscopic agglomeration for over six months in buffer solutions. When evaluated in a carcinoembryonic antigen (CEA), CLEIA, our microspheres achieved an ultra-low limit of detection (LOD) of 0.055 ng·mL⁻¹ and high analytical recovery (93.37–108.25%). In a head-to-head comparison with industry-standard commercial magnetic beads, the engineered microspheres delivered stronger chemiluminescent signals and lower background noise, demonstrating excellent intra-assay (CV < 4.37%) and inter-assay (CV < 10%) precision. This work establishes a scalable, highly stable materials platform that effectively resolves the persistent oxidation limitations, holding immense practical importance for next-generation ultrasensitive clinical in vitro diagnostics. Full article

This research investigates the formation and behavior of sustainable crumb rubber-modified gypsum–cement–pozzolan (GCP) composites, with a view to their use in a broad concept for construction. GCP binders are gaining attention as a low-carbon replacement for Portland cement, and the addition of recycled rubber helps the achievement of circular economy goals and potentially increases durability. The present research evaluates the impact of crumb rubber (CR) on the mechanical strength, water absorption, dimensional stability, and freeze–thaw resistance of 3D-printed GCP-rubber composites. Composite blends of variable proportions of crumb rubber were prepared at constant binder ratios. Mechanical properties were defined by prism specimens (40 × 40 × 160 mm) by the flexural and compressive strengths, and deformation was determined by micrometers to measure longitudinal strain as a function of curing. Water absorption was determined prior to freeze–thaw cycling to define pore saturation. Durability was investigated using two approaches: (1) controlled freeze–thaw experiments on cube specimens, with XF1 grade performance achieved, and (2) ultrasonic pulse velocity (UPV) testing of specimens 3D-printed for assessing internal structural change after long-term frost exposure. Results showed that compressive strength decreased moderately (10–20%) with increasing rubber content from 17% up to 50%, while flexural strength improved up to 15%, showing the elastomeric action of CR. Water absorption was reduced by 5–8% in the rubber-modified blends due to the hydrophobic character of rubber. Deformation tests also confirmed minimum length variation (<0.02%) during curing. Freeze–thaw durability was enormously improved, and test specimens retained more than 95% of initial strength. UPV measurements detected only a relatively modest velocity drop (~50 m/s) after 36 days cycling with subsequent stabilization up to 200 days, demonstrating long-term internal structure with minimal progressive damage. In summary, the findings demonstrate that GCP composites with crumb rubber incorporated are printable, dimensionally stable, and capable of freeze–thaw degradation resistance. Despite a moderate loss of compressive strength, the balance of introduced durability and sustainability suggests their competence as viable materials for additive manufacturing in construction. Full article

The three-phase region of Mo₃Si-Mo₅Si₃-Mo₅SiB₂(MoSiB) exhibits excellent high-temperature oxidation resistance and is considered a highly promising high-temperature structural material. However, the presence of porous structures significantly increases the surface area exposed to oxidation. Metallic porous materials often suffer from inadequate corrosion resistance and insufficient high-temperature oxidation resistance, whereas ceramic porous materials are plagued by high brittleness. Intermetallic compounds offer a combination of the advantages of both metals and ceramics. Nevertheless, the high-temperature oxidation behavior of porous MoSiB has not yet been systematically elucidated. The study systematically investigates the effect of pore structure on the high-temperature oxidation behavior of porous MoSiB at 1000 °C and 1300 °C, with a focus on oxidation kinetics, phase evolution, surface and cross-sectional morphology and underlying oxidation mechanisms. The effects of porosity and temperature on the oxidation process are also analyzed. The results indicate that at 1000 °C, the material exhibits uniform oxidation, with lower porosity contributing to better oxidation resistance. At 1300 °C, oxidation is limited to the surface layer, where low-viscosity SiO₂(B) rapidly seals the pores to form a dense protective layer. This research reveals the high-temperature oxidation mechanism and phase evolution of porous MoSiB, providing a theoretical foundation for its application in high-temperature structural fields. Full article

With the rapid development of the edible fungus industry, the environmental pressure and resource waste caused by the massive generation of fungal residue have become increasingly prominent. Meanwhile, heavy metal wastewater pollution and the growing demand for clean energy pose dual challenges to sustainable development. This study focuses on Auricularia cornea var. Li. fungal residue, exploring the establishment of a multi-level resource utilization pathway integrating “porous carbon material preparation—heavy metal adsorption—photocatalytic hydrogen evolution.” Firstly, the Auricularia cornea var. Li. residue-based porous carbon material was examined by combining hydrothermal carbonization, activation and slow pyrolysis. In optimal conditions, the porous carbon obtained yielded a surface area of 675.56 m²/g and formed a composite pore structure consisting of micropores with coexisting micropore and mesopore. Secondly, we performed batch adsorption experiments to study the effects of solution pH, adsorbent dosage and contact time and the adsorption behavior via fitting adsorbing kinetic models. Under optimal conditions, Cd(II) removal efficiency reached 92.36% and an equilibrium adsorption capacity of 92.47 mg/g. We used Cd(II) adsorbed porous carbon as a cadmium source and converted into a CdS photocatalyst using a hydrothermal sulfidation process. The CdS prepared using sodium sulfide as a sulfur source gave an average hydrogen evolution rate of 668.01 μmol·g⁻¹·h⁻¹ and showed higher photocatalytic performance for water splitting to produce hydrogen. Full article

The preparation of tunnel slag mortar (TSM) represents a sustainable strategy to enhance the resource utilization efficiency of tunnel slag. Toughening TSM via the in situ polymerization of acrylamide (AM) is effective in mitigating the risk of cracking during service. However, the limited understanding of the temperature and humidity sensitivity of AM-modified TSM poses challenges in establishing optimal curing regimes. In this study, low-field nuclear magnetic resonance (LF-NMR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to systematically investigate the evolution of hydration kinetics, hydration products, pore structure, and micromorphology of AM-modified TSM under various curing conditions. The results indicate that AM incorporation retards early hydration but does not alter the types of hydration products. Increasing the curing temperature can alleviate this adverse effect, and a 3% AM dosage exhibits a stronger hydration-promoting effect at 40–60 °C. The efficacy of AM on pore refinement is highly environment-dependent: a 3% dosage yields optimal pore refinement at 20 °C, whereas high temperatures induce pore coarsening. Furthermore, compared to conventional TSM, AM-modified TSM exhibits higher sensitivity to curing humidity, underscoring that adequate moisture is critical for optimizing its pore structure. Full article

The deep marine shale of the Wufeng–Longmaxi (WF–LMX) Formation in the Sichuan Basin is characterized by laterally continuous thickness, high porosity, and significant gas content, making it a representative shale reservoir with considerable resource potential. This study investigates the heterogeneity of pore structures and their controlling factors using shale samples from three representative wells, based on low-temperature nitrogen adsorption and mercury intrusion data. The reservoir can be classified into three main lithofacies: mixed siliceous shale (MSS), clay-rich siliceous shale (CSS), and siliceous clay mixed shale (SMS). The results show that siliceous shales (MSS and CSS) exhibit higher total organic carbon and quartz contents, with more developed pore systems. Among them, the CSS exhibits the highest specific surface area and the largest mesopore and macropore volumes, indicating a greater development of larger pores and superior reservoir quality. All three shale facies exhibit clear single and multifractal characteristics. The average D₁ and D₂ values (fractal dimensions from nitrogen adsorption at P/P₀ < 0.45 and >0.45, respectively) are higher than D_Hg, (fractal dimension from mercury intrusion), indicating greater pore-surface roughness than internal pore structure complexity and stronger heterogeneity in larger pores. The D(q)–q spectrum shows a left-wide/right-narrow pattern, whereas the α–f(α) spectrum exhibits the opposite trend. The branch-width ratios S_kd and S_ka (indices of pore-size distribution complexity and heterogeneity) are both <0.1, suggesting that heterogeneity is more pronounced in low-probability regions. Fractal and multifractal analyses reveal significant pore structure heterogeneity across different lithofacies, with CSS showing relatively more homogeneous pore structures, whereas MSS exhibits stronger heterogeneity and poorer connectivity. The heterogeneity of shale reservoirs is primarily controlled by pore development, especially micropores and mesopores, and is strongly influenced by total organic carbon and quartz content. Full article

Quantitative characterization of permeability in porous media represents a central problem in filtration theory, geosciences, and materials engineering. Standard numerical approaches, including finite element methods and Lattice Boltzmann simulations, typically require extensive domain-specific expertise together with specialized computational software. This motivates the development of computationally simpler and more accessible geometric approaches applicable directly to binary volumetric data. We introduce a novel algorithmic framework for the analysis of porous structures that reformulates permeability-related characterization in terms of discrete geometry and graph-based computation. The method combines parallel raster-grid and graph representations of a binarized three-dimensional CT image. The principal transport-limiting feature of the pore network, interpreted as the minimal constriction governing connectivity, is identified through iterative morphological dilation coupled with a three-dimensional scanline seed-fill procedure. In addition, a dichotomous bisection strategy is proposed to accelerate the determination of the critical bottleneck scale. The proposed methodology was evaluated on five volumetric datasets of size 100 × 100 × 100 voxels obtained from CT-derived porous structures. Experimental results demonstrate that dilation- and erosion-based formulations yield equivalent estimates of the bottleneck parameter in four of the five investigated samples. Furthermore, incorporation of the bisection optimization reduces computational time in three-dimensional experiments by approximately 50% relative to sequential iteration. The presented approach provides a computationally efficient and fully open-source alternative to conventional physics-based permeability solvers for binary porous media. The resulting bottleneck parameter b should be interpreted as a discrete geometric invariant characterizing the pore-network connectivity and minimal transport cross-section. It is not intended to replace the absolute permeability coefficient K appearing in Darcy’s law, but rather to serve as an independent structural descriptor suitable for comparative and topological analysis of porous systems. Full article

The growing interest in functional bakery products has driven research toward the incorporation of non-conventional plant materials rich in dietary fiber. In this study, the effects of partial substitution of wheat flour with ground kudzu root (Pueraria lobata) at levels of 3%, 6%, 9%, and 12% on dough rheology and bread quality were investigated. Farinograph analysis showed that kudzu addition slightly increased water absorption and dough development time, while significantly improving dough stability and the farinograph quality number. At the same time, a higher degree of dough softening indicated partial weakening of the gluten network at higher substitution levels. The incorporation of kudzu root significantly increased bread yield due to enhanced water retention associated with its high dietary fiber content. However, a reduction in specific volume was observed at the highest substitution level (12%), indicating limitations in gas retention capacity. Crumb structure analysis revealed a shift toward a finer and more homogeneous pore distribution with increasing kudzu content, accompanied by a reduction in large pores. These structural changes were reflected in texture profile analysis, where increased hardness and chewiness were observed, particularly at higher substitution levels, while cohesiveness and springiness were only slightly affected. Partial substitution with kudzu root powder also resulted in a significant increase in total phenolic content, flavonoid content, and antioxidant potential of the breads, with the highest values observed in samples containing 12% kudzu root powder. In addition, breads enriched with kudzu root showed reduced digestible starch content compared with the control sample. Despite these modifications, breads enriched with up to 9% kudzu root maintained acceptable technological quality, balancing improved water retention with moderate changes in structure and texture. The results demonstrate that kudzu root can be used as a functional ingredient in wheat bread, contributing to increased dietary fiber content while maintaining satisfactory processing and quality characteristics. Full article

Ultra-high-performance concrete incorporating coarse aggregates (UHPC-CA) exhibits pronounced multi-scale heterogeneity and staged damage evolution. However, existing single-scale reinforcement strategies often fail to address the complete micro-to-macro fracture process, leaving a critical research gap in achieving full-stage crack control. To address this, this study introduces a novel cross-scale toughening strategy using hybrid steel fibers (SF) and calcium carbonate whiskers (CCW), and decouples the coupled influences of water-to-binder (W/B) ratio, coarse aggregate (CA), and multi-scale fibers via an orthogonal design. Mechanical properties, fiber dispersion, and pore structure are jointly characterized to establish structure–property relationships. An optimal composition (W/B = 0.32, CA = 18%, SF = 2%, CCW = 1%) is identified, achieving a balanced enhancement of strength and ductility. Results indicate that matrix densification is primarily controlled by W/B via pore refinement, while mechanical performance is governed by the interplay between fiber spatial uniformity and interfacial integrity; the roles of CA and CCW are clearly stress-state dependent. Furthermore, a novel cross-scale synergistic mechanism is revealed, in which micro-scale CCW regulates microcrack initiation and stabilizes the pre-peak response, whereas macro-scale SF dominates post-peak behavior through crack bridging and pull-out energy dissipation. This sequential activation enables a full-stage enhancement of tensile performance, shifting failure from brittle localization to pseudo-ductile multiple cracking. The findings provide a correlative framework for tailoring UHPC-CA through multi-scale hybrid reinforcement. Full article

Structural and functional soil degradation under conventional tillage has reached a critical point, requiring a shift towards conservation practices to mitigate the negative effects of climate change. This study evaluated the multi-year effects (2021–2024) of conventional tillage (CT), conservation deep tillage (CD), and conservation shallow tillage (CS) on soil physical properties (density, air capacity, and water content), water distribution, infiltration rate, and maize yield in a silty Gleysol. Soil water content (SWC), i.e., distribution, was monitored using PR2 profile probes at depths of 10, 20, 30, and 40 cm. CT treatment resulted in impaired soil physical properties, characterized by a significant increase in air capacity (+233.9%) and with a significant decrease in volumetric water content (qw, ≈40%). In contrast to CT (47.91 cm h⁻¹), the CS treatment resulted in more favorable hydraulic properties, i.e., and infiltration rate of 102.29 cm h⁻¹, by 2024. Statistical analysis (R², RMSE) confirmed that CS provides the most reliable and consistent environment for monitoring SWC. While maize yields were significantly higher in CT during the initial year (2021; 9.5 t ha⁻¹ vs. 8.4 t ha⁻¹ in CS), no significant differences were observed by 2024, and all tillage systems reached yields of ≈13.0 t ha⁻¹. The results suggest that after the four-year study period, CS tillage stabilized soil hydraulic properties and pore continuity, thereby resulting in maize yields equivalent to those of CT. Therefore, CS has proven to be a more resilient and effective strategy for sustainable water management in silty Gleysols. Full article

Capillary imbibition is the process by which liquids are absorbed into porous materials as a result of capillary pressure differences at the pore scale. Accurate characterization of imbibition dynamics, particularly in the presence of gravitational potential, is essential for understanding fluid transport in diverse systems such as soil, fractured rocks, filtration media, and plant roots. This study presents systematic imbibition experiments using filter papers with pore sizes of 2.5 µm, 11 µm, and 20 µm, each inclined at 80° to quantify the influence of gravitational potential on imbibition behavior. For horizontally positioned samples, the imbibition front propagated radially and symmetrically, exhibiting a power law dependence on time. The measured temporal exponents ranged from 0.386 to 0.403, consistently lower than the theoretical value of 1/2 predicted by the Lucas–Washburn law. With increasing permeability, the temporal exponent approached the Washburn limit, indicating a marked dependence of imbibition dynamics on pore structure. For the inclined configuration at an 80° angle, the imbibition fronts remained nearly circular but exhibited a pronounced displacement of the front center toward gravity. This displacement increased with permeability, from approximately 0.497 cm for the 11 µm filter paper to 3545 cm for the 20 µm filter paper, highlighting the combined effects of permeability and gravitational potential on fluid movement. Furthermore, the advance of the imbibition front was significantly slower in the smallest pores (2.5 µm) compared to the larger ones. Experimental results were evaluated against a theoretical model proposed by Medina, demonstrating moderate quantitative agreement at early times, when gravitational potential effects are less significant. These findings confirm that both the temporal scaling exponent and the spatial evolution of the imbibition front are governed by the porous medium’s permeability and inclination angle, providing experimental evidence of deviations from ideal Washburn behavior in real porous systems. Full article