Evaluation of gas content prediction models for deep coal seams: A case study from the Daning–Jixian Block, Eastern Ordos Basin

Effect of water diversion flow on water quality improvement and saturation threshold in urban plain river networks.

Effect of soil volume changes on the volumetric water content and saturation degree of the soil-water characteristic curve

Combining in-field and edge-of-field practices enhances nitrate reduction in tile-drained catchments.

Diffuse-porous and ring-porous xylem types did not influence branch hydraulic responses along a rural-urban gradient

Lianas are particularly abundant in seasonally dry tropical forests, where most species flower during the dry season. While hydraulic differences of vegetative organs between lianas and trees are well-documented, floral hydraulic strategies and their potential role in liana expansion remain unclear. To characterize divergence in floral water-use strategies between lianas and trees, we examined 24 floral traits related to water transport, storage, drought tolerance, and pollinator attraction in 16 liana and 16 tree species of Bauhinia s.l. from a tropical seasonal rainforest in Yunnan, China. Liana flowers exhibited greater petal vein density, stomatal density and size, flower mass per area, and drought tolerance than tree flowers, which showed higher saturated water content and hydraulic capacitance. Liana flowers exhibited a trade-off between hydraulic efficiency and safety, but trees did not. Life forms also differed in trait coordination linking hydraulic structure, function, and reproduction. Our findings reveal divergent floral hydraulic syndromes: lianas adopt structurally reinforced, drought-tolerant designs for canopy flowering under high vapor pressure deficit, while trees rely on internal water reserves to buffer water loss. This study provides the first organ-level evidence that divergent floral hydraulic strategies underpin reproductive success and may help explain liana dominance in seasonally dry tropical forests under climate change.

Our knowledge of the transport and interfacial behavior of per- and polyfluoroalkyl substance (PFAS) precursors in the vadose zone remains incomplete, with significant knowledge gaps. This study investigated unsaturated transport of two precursors, 6:2 fluorotelomer sulfonate (6:2 FTS) and perfluorohexanesulfonamido propylamine (PFHxSAm), using air-water interfacial tension measurements, column experiments, and mathematical modeling. PFHxSAm exhibited substantially greater surface activity than 6:2 FTS and perfluorooctanoate (PFOA), leading to a pronounced retention in unsaturated columns. PFHxSAm was also determined as volatile, with an air-water partition coefficient of log Kaw = -4.45 (95% C.I. [-4.67, -4.31]) [log(cmw3/cmair3)], yet gas partitioning and diffusion processes were shown to contribute negligibly to its retention at ∼50% water saturation, likely due to the relatively low volatility. Rate-limited mass transfer at the air-water interface (AWI) was observed for 6:2 FTS and PFHxSAm, with desorption occurring 5-9 times more slowly than adsorption. Mixture experiments provide the first experimental evidence of synergistic AWI adsorption between 6:2 FTS and PFHxSAm, contrasting with the competitive behavior reported for perfluoroalkyl acids. Modeling of the transport experiments indicates that synergistic interactions increased AWI adsorption of PFHxSAm and 6:2 FTS by up to 1.9- and 11.3-fold, respectively, relative to their single-solute behavior. These findings demonstrate that synergistic interfacial interactions can substantially increase PFAS retention in the vadose zone, with important implications for their fate, transport, and risk assessment.

In situ thermal remediation of non-aqueous phase liquid (NAPL)-contaminated soils involves coupled heat transfer, phase change, and multiphase migration processes, which complicate the interpretation of temperature signals. Under fully saturated conditions, NAPL pools remain capillarity confined and co-boiling proceeds in place, often producing temperature plateaus that reflect local phase change and removal. However, heating-induced desaturation can alter capillary entry resistance and phase connectivity, enabling NAPL redistribution and modifying the temperature response. In this study, a controlled two-dimensional sandbox system with spatially resolved temperature measurements and visualization was used to investigate NAPL migration and temperature behavior under saturated and heating-induced unsaturated conditions. Four representative NAPLs (n-hexane, n-octane, trichloroethylene, and perchloroethylene) were examined. The results show that, under saturated conditions, co-boiling remains spatially localized and temperature plateaus correspond to local removal behavior. Under heating-induced desaturation, reduced capillary constraints and evolving phase connectivity allow NAPL migration, leading to shortened, shifted, or absent temperature plateaus. LNAPLs primarily migrate with declining water saturation, while DNAPLs tend to redistribute toward deeper and cooler regions. These observations provide a mechanistic basis for understanding how the temperature response is influenced by saturation-dependent migration behavior. The results indicate that temperature plateaus remained representative of local NAPL removal when co-boiling occurred in place but became less representative of local residual distribution when redistribution occurred under heating-induced desaturation.

This study focuses on the water absorption process of illite, a heavy clay mineral of oil shale, and its related physical, chemical and mechanical properties. The interaction between water and illite molecules under different temperature, pressure and water saturation was studied by coupling molecular simulation. The changes and influence characteristics of basic physical properties (volume, density, expansion effect) and mechanical properties (elastic modulus, Poisson ‘s ratio, mechanical heterogeneity) of hydrated illite were analyzed. The results of molecular simulation show that the water absorption of illite mainly expands in the z direction of the crystal, the pressure can inhibit the expansion, and the temperature and water saturation promote the expansion. The interaction between oxygen atoms and potassium ions in water is more intense under pressure, and temperature and water saturation promote the diffusion of water molecules. The elastic modulus of illite increases with the increase of pressure and decreases with the increase of temperature and water saturation. The research results provide a theoretical basis for the stability evaluation of clay minerals in the fields of petroleum exploitation and geotechnical engineering, and reveal the microscopic mechanism of illite hydration degradation under multi-field coupling conditions.

This study employed an integrated petrophysical workflow that combines conventional well-log interpretation with routine core analysis to evaluate the Nukhul Formation in the Rudeis-Sidri Field and to assess its hydrocarbon potential quantitatively. The Sidri-14 well, Gulf of Suez, penetrates the Lower Miocene Nukhul Formation, a sequence of sandstone, shale, and limestone. Petrophysical evaluation, supported by core (215 samples) and well log analysis, subdivided the formation into four reservoir units (A-D). Units A, B, and C exhibit low porosity (4.3-13.6%), and low permeability (0.03-13.099 mD), with a heterogeneity coefficient (V) of 0.92, classifying the formation as highly heterogeneous with variable but moderate hydrocarbon saturation, while water saturation (Sw) frequently exceeds 50%, limiting net pay, whereas Unit D, being carbonate-dominated, shows no reservoir potential. The porosity-permeability relationship (R2 = 0.93-0.98) confirms that permeability is strongly controlled by pore-throat size. By employing hydraulic flow unit (HFU) classification (via RQI, NPI, FZI, and stratigraphic Lorenz techniques), most samples fall within tight/poor quality domains (RQI < 0.25 μm, R35 < 1 μm), requiring stimulation for economic recovery. Hydraulic Flow Unit (HFU) classification subdivides the reservoir into 8 HFUs, where HFU-1 and HFU-2 contribute the largest portion of flow (14.11% and 16.52% of total flow capacity) and equivalent to PSRT1 and PSRT2, which are characterized by the highest RQI and FZI values, wide pore-throat sizes, high permeability, and excellent flow capacity, while HFU-8 contributes 0%, highlighting uneven productivity distribution. This integration reveals that the Nukhul Formation is classified as an unconventional, tight reservoir with limited but heterogeneous hydrocarbon potential. Productive intervals exist but are restricted to specific HFUs, meaning advanced recovery techniques (hydraulic fracturing, horizontal drilling) are essential for efficient hydrocarbon exploitation.

This study investigates the influence of geological characteristics and Soil-Water Characteristic Curve (SWCC) parameters on the collapse potential (CP) of unsaturated soils from loessic and lacustrine-alluvial deposits in Iran. Laboratory experiments-including SWCC determination, suction-controlled modified consolidation tests, and microstructural analyses (SEM and XRF)-were conducted on samples reconstructed to match natural moisture and in-situ density. The results show that matric suction significantly affects compressibility and collapse behavior, with higher suction and Pressure at wettings increasing CP. SEM observations revealed microstructural rearrangements and denser particle packing consistent with hydraulic and mechanical responses, reflecting the influence of depositional environment and mineralogy. To enhance predictive capability, machine learning models were trained on the integrated dataset, with Gradient Boosting achieving the highest predictive performance (R² = 0.859, RMSE = 1.273). Permutation importance analysis identified Pressure at wetting, matric suction, and saturated volumetric water content (θs) as the most influential mechanistic predictors. These findings demonstrate a strong quantitative association between suction-controlled SWCC parameters and collapse potential, indicating that the incorporation of hydraulic variables significantly improves predictive accuracy compared with conventional index-based approaches. The proposed integrated experimental-hydraulic-machine learning framework provides a reliable preliminary tool for collapse assessment and strengthens the mechanistic basis for geotechnical design in unsaturated collapsible soils.

Diffusion of iodide in compacted Beishan Granite: Impact of saturation duration, ionic strength, and dry density.

ABSTRACT The soil–water characteristic curve (SWCC) illustrates the relationship between suction and water content, essential for understanding unsaturated soil behaviour. Although SWCCs have been studied for various soils, limited research has addressed cement-treated clays and the reproducibility of model parameters. This study evaluates SWCCs derived from repeated matric suction measurements on clay samples treated with four soil–cement ratios. For each ratio, two sets of measurements at four water contents were performed, yielding 11 SWCCs fitted with each of the van Genuchten and the Fredlund and Xing models across different combinations of the repeated measurements. Suction and model parameter evaluation results show that matric suction increases markedly with cement content. While the saturated water content remained essentially constant, the air-entry suction, residual water content, and slope of the SWCCs were influenced by cement content. Parameter variability was observed across combinations, with the van Genuchten residual water content exhibiting the highest dispersion.

Synergistic water absorption and release in water storage clay: Roles of particle size and hierarchical porestructure.

We have previously demonstrated that a non-natural tetrazole containing peptide (2), which mimics the MEEVD Short Linear Motif (SLiM) found at the Heat Shock Protein 90 (HSP90) C-terminus, disrupts the transient protein–protein interaction (PPI) formed between HSP90 and the HSP70-HSP90 organizing protein (Hop) co-chaperone. However, the native MEEVD SLiM (1) showed negligible inhibitory activity despite similar binding affinity to the interacting HopTPR2A domain. To investigate the origin of this discrepancy, we combined native mass spectrometry (nMS) coupled to ion mobility (IM) with saturation transfer difference (STD) and water ligand observed via gradient spectroscopy (WLOGSY) NMR to interrogate the interaction of peptides 1 and 2 alongside a series of peptide derivatives with HopTPR2A. Collectively, these data revealed that the variation in sequence between peptides 1 and 2 imparts subtle variations in conformational stability and magnetization transfer, indicating that differences in PPI modulation arise from altered binding mode rather than binding affinity. These results not only provide a structural framework for developing peptidomimetic HSP90-Hop PPI inhibitors, but a generalized strategy for exploiting transient PPIs for drug discovery.

Hydrogen (H2) storage in subsurface formations has recently gained attention as a promising large-scale energy storage solution. Although previous studies have revealed distinct displacement behaviors between H2 and other gases such as nitrogen (N2) and carbon dioxide (CO2) in high-permeability sandstones, the mechanisms governing H2 migration in tight formations remain largely unexplored. To provide experimental observations that may help improve the understanding of H2 migration in tight reservoirs, we conducted H2 flooding experiments on a tight sandstone sample from the Ordos Basin under pore fluid pressures of 0.5, 1, and 2 MPa. Dynamic core flooding processes were monitored using a low-field nuclear magnetic resonance (NMR) analysis system. The capillary number (Nc) in this work ranged from 1.7 × 10−9 to 3.4 × 10−9, indicating a capillarity-dominated flow. H2 saturation in the tight sandstone increased from 41.9% to 53.3% and then to 57.7% with increasing pore fluid pressure. Under a pore fluid pressure of 0.5 MPa, H2 initially displaced water in small pores (T2 &lt; 10.5 ms), leading to prolonged fluctuations in water content over 136 min before significant displacement occurred in large pores (10.5 ms &lt; T2 &lt; 6579.3 ms). In contrast, at a pore fluid pressure of 2 MPa, the water in large pores was more significantly impacted, with a marked decrease in water saturation observed after 8 min of flooding. These findings provide direct experimental evidence of pressure-dependent and pore-scale selective displacement patterns of H2 in tight sandstone, offering new insights into the fluid dynamics that control hydrogen injectivity and storage efficiency in low-permeability reservoirs.

The studied sediments of the Tyumen suite can be characterized by difficulties in confirming oil saturation coefficients derived from well testing data, including the electrical resistivity. Alternative estimation of oil saturation using a capillary model is complicated. This is because the above-mentioned sediments have a complex deposit structure. In some instances, these deposits are limited by a conventionally accepted depth of the lower oil-saturated interval, without justifying the free water level. For this reason, we must estimate deposit heights indirectly using only core analysis data. This article aims to develop indirect methods for evaluating deposit height within the constraints of geological models. To achieve this aim, we first generalized and analyzed capillary properties under both atmospheric and thermobaric conditions. We utilized direct indicators of oil saturation from core fluorescence under ultraviolet light, to determine boundary values for reservoir properties in the zone of maximum saturation. We then selected appropriate values for residual water saturation. Using these values, we compared total porosity with effective and dynamic porosity and obtained consistent boundary values. Based on the established values for residual water saturation and available capillary pressure curves, we calculated capillary pressures and formation heights. As a result, the results show that capillary pressures ranging from 7 atm to 12 atm are sufficient to establish residual water saturation in the Tyumen suite deposits within the studied areas. These pressures correlate to reservoir heights between 90 to 160 m. This approach facilitates the estimation of oil saturation coefficients using the capillary model in reservoirs with uncertain fluid contacts. It can also serve as supplementary tool for justifying individual lenses and blocks within geological models.

Static storage estimates for depleted gas fields using volumetric and production approaches

Coupled channel–electrode design for water transport and performance stability in proton exchange membrane fuel cells

Effects of hot-air pretreatment in semi-dry milling on rice starch gelatinization, rheological properties, and eating quality of wet rice noodles.