Permeability Characteristics Research Articles

An Ala/Glu difference in E1 of Cx26 and Cx30 contributes to their differential anionic permeabilities.

Two closely related connexins, Cx26 and Cx30, share widespread expression in the cochlear cellular networks. Gap junction channels formed by these connexins have been shown to have different permeability profiles, with Cx30 showing a strongly reduced preference for anionic tracers. The pore-forming segment of the first extracellular loop, E1, identified by computational studies of the Cx26 crystal structure to form a parahelix and a narrowed region of the pore, differs at a single residue at position 49. Cx26 contains an Ala and Cx30, a charged Glu at this position, and cysteine scanning in hemichannels identified this position to be pore-lining. To assess whether the Ala/Glu difference affects permeability, we modeled and quantified Lucifer Yellow transfer between HeLa cell pairs expressing WT Cx26 and Cx30 and variants that reciprocally substituted Glu and Ala at position 49. Cx26(A49E) and Cx30(E49A) substitutions essentially reversed the Lucifer Yellow permeability profile when accounting for junctional conductance. Moreover, by using a calcein efflux assay in single cells, we observed a similar reduced anionic preference in undocked Cx30 hemichannels and a reversal with reciprocal Ala/Glu substitutions. Thus, our data indicate that Cx26 and Cx30 gap junction channels and undocked hemichannels retain similar permeability characteristics and that a single residue difference in their E1 domains can largely account for their differential permeabilities to anionic tracers. The higher anionic permeability of Cx26 compared with Cx30 suggests that these connexins may serve distinct signaling functions in the cochlea, perhaps reflected in the vastly higher prevalence of Cx26 mutations in human deafness.

Permeability characteristics and empirical prediction of fine sandy soils stabilized by cement and metakaolin

Permeability characteristics and empirical prediction of fine sandy soils stabilized by cement and metakaolin

Distributed parameter model of dynamic contrast-enhanced MRI in the identification of IDH mutation, 1p19q codeletion, and tumor cell proliferation in glioma patients

ObjectivesTo investigate the clinical value of hemodynamic parameters derived from dynamic contrast-enhanced MRI (DCE-MRI) in predicting glioma genotypes including isocitrate dehydrogenase (IDH) mutation, 1p/19q codeletion status and the tumor proliferation index (Ki-67) noninvasively. And to compare the diagnostic performance of parameters of distributed parameter (DP)model and extended Tofts (Ex-Tofts) model.Materials and methodsDynamic contrast-enhanced MRI (DCE-MRI) data of patients with glioma were prospectively enrolled from April 2021 to May 2023. The imaging data were analyzed using DP and Ex-Tofts model for evaluating the perfusion and permeability characteristics of glioma. Comparisons were performed according to IDH genotype in all glioma patients and 1p/19q codeletion in IDH mutation glioma patients. Receiver operating characteristic (ROC) curves were generated for DCE-MRI parameters. The Spearman rank correlation coefficients were calculated between DCE MRI parameters and Ki-67 index.ResultsIn IDH-mutation gliomas, a higher blood flow (F) was found in 1p/19q codeletion gliomas than in 1p/19q intact gliomas. No parameter derived from Ex-Tofts model showed significant differences in predicting 1p/19q status. Fractional volume of interstitial space (Ve) derived from both the DP and Ex-Tofts models exhibited optimal performance in predicting IDH genotype (AUC = 0.818, 0.828, respectively). Ve also showed the highest correlations with Ki-67 LI within their respective models in all gliomas (ρ = 0.62, 0.61), indicating comparable moderate positive associations. Ki-67ConclusionDP model showed a clear advantage in predicting 1p/19q status compared to Ex-Tofts model. The DP and Ex-Tofts models performed similarly in predicting IDH mutation and Ki-67 index.

Experimental and numerical study of shear strength on the slide zone soil by the coupling of seepage and shear test

The stability of reservoir landslides is determined by the strength of the slide zone. Using both experimental and numerical techniques to analyze the strength of the slide zone has been widely used in the research of reservoir landslides. However, few models consider the strength of the coupling between seepage and shear. This paper aims to analyze the shear strength of slide zone soil combined with different stresses by using the directed shear test and particle flow code PFC2D. The results indicated that slide zone soil clearly experienced the strain-hardening without seepage. While a specific strain-softening phenomenon was observed because the introduction of seepage reduced the shear strength significantly, the internal friction angle demonstrated a higher sensitivity to seepage stress compared to cohesion as the seepage stress increased. The direction and amount of flow velocity dynamically alter during the shear process, as revealed by numerical simulation results, suggesting that the shear strength was nonlinear with increasing seepage stress and changed structure. It can be assumed that seepage deterioration in the Huangtupo landslide is a dynamic process that influences the structure, strength and permeability characteristics.

Evaluation of CO2/Water Imbibition Relative Permeability Curves in Sandstone Core Flooding—A CFD Study

Greenhouse gases such as CO2 can be safely captured and stored in geologic formations, which in turn can reduce the carbon imprint in the Earth’s atmosphere and therefore help toward reducing global warming. The relative permeability characteristics in CO2/brine or CO2/water systems provide insight into the CO2 trapping efficacy of formations such as sandstone rocks. In this research, CO2/water imbibition relative permeability characteristics in a typical sandstone core sample are numerically evaluated. This work uses transient computational fluid dynamics (CFD) simulations to study relative permeability characteristics, and a sensitivity analysis is performed based on two different injection pressures and absolute permeability values of the sandstone rock material. Results show that when the irreducible water fraction remains unchanged, the imbibition relative permeability to the non-wetting phase decreases with an increase in injection pressure within the sandstone core sample. Also, with the irreducible water fraction being unchanged, relative permeabilities to both non-wetting and wetting phases decrease with an increase in the absolute permeability of the rock material. Finally, at irreducible water saturation, relative permeability to the gas phase decreases with an increase in injection pressure.

Prediction of permeability characteristics of mine slurries and sediments using finite-strain framework by optimisation algorithms

Determining the permeability characteristics of mine tailing slurries through laboratory finite-strain consolidation tests is costly due to the extensive testing required. An alternative approach involves back-predicting hydraulic conductivities from settling column test data. This study employed settlement and excess pore pressure data as inputs in optimising the permeability parameters using the finite-strain consolidation (FSC) framework. The proposed approach used the finite difference method to solve the governing equation for FSC in the forward analysis. Two novel variants of the Artificial Bee Colony (ABC) algorithm, namely the Modified Artificial Bee Colony (MABC) and the Hybrid Artificial Bee Colony (HABC) algorithms, were used to back-predict the hydraulic conductivity function parameters from the FSC test data. These models predicted the permeability characteristics using the temporal variation of the settlements for six slurries and excess pore pressure dissipation data for four slurries. The performance of the proposed algorithms along with Hybrid Particle Swarm Optimisation (HPSO) was compared with the conventional optimisation algorithms, viz., PSO, ABC, and Quantum PSO (QPSO). The HABC and HPSO exhibited remarkable stability, consistently converging to identical solution sets across multiple iterations, thereby outperforming other algorithms in this study. Despite its higher time complexity by HABC relative to the other evaluated methods, this complexity is warranted for enhanced robustness. The current study is helpful in brining practical and reliable methodologies for estimating the hydraulic conductivity function from field-scale conductivity (FSC) data, providing critical insights for the safe and efficient management of slurry wastes.

Laboratory assessment of the effect of rice husk, groundnut shells and RHA on the shear, permeability and consolidation of clayey sands

Utilizing waste materials to improve soil properties can result in cost savings and environmental benefits. This study aims to determine the effect of adding agricultural wastes like rice husk ash (RHA), rice husk (RH), and groundnut shells (GS) to clayey sands from Mysore district, India. The study focused on the undrained strength, permeability and volume change behaviour of soils mixed with RHA, RH and GS. The soil samples were mixed with varying amounts of RHA (5%, 10%, 15%, and 20%) and RH-GS (1%, 2%, 3%, 4%, and 5%) and cured for 1, 7, 14 and 21 days. These blended specimens were then used to determine the maximum dry density (MDD), optimum moisture content (OMC) and unconfined compressive strength (UCS). The soil mixture containing 5% RHA and 4% (RH + GS) yielded optimal results in the UCS test. Further tests, including unconsolidated undrained (UU) triaxial, permeability and consolidation tests, were conducted on the parent soil and the soil composite with 5% RHA and 4% (RH + GS). From the undrained test, the strength increased for the soil admixture, with a reduction in the cohesion and an increment in the friction angle, compared to that of the parent soil. The experimental results also showed improvement in the permeability and consolidation characteristics of the blended soil. As RH, GS, and RHA are abundant and considered to be agricultural waste products, using them represents an innovative, sustainable, and cost-effective solution with promising potential for soil improvement.

Comprehensive magnetic properties of grain-oriented silicon steel sheet considering anisotropy under mechanical stress

The cores of transformers and reactors are subjected to mechanical stresses during both manufacturing and operation, these stresses exert an influence on the magnetic properties of the cores. Additionally, there exists rotating magnetic flux within the cores during operation. Therefore, it is necessary to further consider the magnetic properties of grain-oriented silicon steel sheet in the direction perpendicular to the rolling direction. To delve deeply into the comprehensive magnetic properties of grain-oriented silicon steel sheet under mechanical stress, with a particular focus on both the rolling direction and the direction perpendicular to it, this paper presents the establishment of a comprehensive magnetic properties measurement platform for grain-oriented silicon steel sheet that possesses stress adjustment capabilities. Through meticulous measurements, the impacts of tensile and compressive stresses on the magnetic hysteresis loops, B-H curves, relative permeability, magnetostriction, and iron loss characteristics of grain-oriented silicon steel sheet in both the rolling direction and the perpendicular direction were obtained and analyzed. The measurement results and subsequent analysis indicate that tensile and compressive stresses exert an influence on the magnetization characteristics of grain-oriented silicon steel sheet. Moreover, the extent of this influence varies between the rolling direction and the direction perpendicular to rolling for both tensile and compressive stresses; In the rolling direction, compressive stress promotes the magnetostriction of the grain-oriented silicon steels, while tensile stress inhibits it. In the direction perpendicular to rolling, both tensile and compressive stresses inhibit the magnetostriction of the grain-oriented silicon steels, with tensile stress exerting a greater inhibitory effect; Tensile stress acts to reduce the iron loss of grain-oriented silicon steels, whereas compressive stress increases it, this pattern is consistently observed in both the rolling direction and the direction perpendicular to rolling.

Innovating sustainability: a holistic approach to insulation panel design from woven sewn-in label selvedge wastes

The textile industry stands out as a significant contributor to environmental pollution, with its escalating material consumption exerting a considerable impact on the ecosystem. The surge in textile waste has spurred a heightened interest in recycling initiatives, particularly focused on transforming textile waste into functional technical products. In response to the increasing demand for insulation materials driven by the imperative to conserve building thermal energy and address rising noise pollution, recycled textile materials have gained prominence for their application in thermal and acoustic insulation. This research delves into the efficacy of insulation materials developed from woven sewn-in label selvedge waste, comprised entirely of polyester fiber. Employing carding and needle punching methods, nonwoven panels are produced from label wastes. Tests are conducted to evaluate the thermal, acoustic, and air permeability attributes of panels varying in thickness and weight. The findings reveal that the thickest panel excel in acoustic insulation, whereas the thinnest panel with least density exhibit notable thermal efficiency and air permeability characteristics.

Quantitative assessment of the 3D pore space and microglobule clustering network to understand chromatographic transport phenomena in polymeric monolithic columns

The 3D pore space and microglobule clustering network of polymer monolithic columns, which exhibited similar external porosity but significantly different chromatographic dispersion and permeability characteristics, were subjected to tomographic imaging followed by stereological analyses. The morphologies of the monolithic support structures were examined using serial-block-face scanning electron microscopy. The statistically computed characteristic chord-length, hydraulic radius and tortuosity of the pore are strongly associated to chromatographic transport processes, in particular, eddy dispersion and mass-transfer resistance contributing to chromatographic dispersion, and permeability of monolithic columns. Moreover, Giddings’ trans-column velocity bias has been quantified in monoliths for the first time. With demonstrated method robustness, the proposed morphological descriptors and the streamlined analysis workflow provide novel insights bridging the structure-performance relationship for future chromatography column design.

Analysis of dynamic characteristics and influencing factors of CO2 low-permeability coal reservoir sequestration

ABSTRACT Abandoned coal seams can be an important carrier for CO2 geological storage. Considering the gas seepage-diffusion and physical adsorption coupling characteristics in the process of CO2 adsorption and storage in coal and rock, a two-dimensional model of coupled flow-solidity for geological storage of CO2 in low-permeability reservoir with double voids was established by introducing the Zhang Hongbin model algorithm and adding the Klinkenberg effect and the compression effect of the rock skeleton in coal reservoirs in the controlling equation for rock deformation. The coupled flow-solid model was solved by using the PDE equation of COMSOL Multiphics program, and the simulation results difference between the new model and the traditional model in terms of sequestration dynamics were compared. The dynamic characteristic of reservoir gas pressure, formation stress, permeability and sequestration density in the process of CO2 geologic sequestration and injection were analyzed, and the influences of injection pressure and injection well diameter on the amount of CO2 sequestration were explored. The results show that the new model is more reasonable for calculating reservoir gas pressure and permeability compared with the Palmer-Mansoori model (PM model), and can simulate the free-state seepage movement of CO2 in the fracture system as well as its physical adsorption process compared with the single-heavy pore medium model. With continuous CO2 injection, the maximum sequestration density was raised to a limit value of about 1000 kg/m3 after 1 year. The date of reaching the limit of the sequestration volume was advanced by about 45 d when the positive pressure of the injected gas was increased from 10 kPa to 50 kPa. This model can reproduce the main parameters including, when affecting the effect, and realize the calculation of parameters such as CO2 density reaching the limit value, sealing limit day, sealing limit amount, which can provide a theoretical basis for further deep understanding of CO2 geological sealing law and scientific development of gas injection scheme.

Permeability characteristics, structural failure characteristics, and triggering process of loess landslides in two typical strata structures

Landslides occurring at the interface of strata are among the most common forms of loess landslides in China. Statistics indicate that significant loess-red silty clay interface landslides induced by irrigation in the Heifangtai Platform than loess-paleosol interface landslides in the South Jingyang Platform. To uncover the permeability characteristics, structural failure patterns, and triggering processes of two typical strata structures. This study employs Nuclear Magnetic Resonance (NMR) and Scanning Electron Microscopy (SEM) techniques to investigate the permeability and structural failure of two soil combination types: loess-red silty clay and loess-paleosol. The results revealed a positive correlation between the stagnant water effect and flow rate, but a negative correlation with the initial water content. Notably, these two typical strata exhibited distinct differences in the stagnant water effect. In loess-red silty clay, continuous filling of mesopores and macropores by fine clay particles, while at the same time the agglomerates disintegration at the interface, thereby enhancing the stagnant water effect. In contrast, loess-paleosol exhibited good connectivity between the mosaic pores at the interface. This facilitated the formation of several elongated microcracks, which acted as dominant channels for infiltration and weakened the stagnant water effect. However, the macroscopic triggering mechanism for loess landslides in both loess-red silty clay and loess-paleosol combination strata remains similar. Irrigation water stagnates within the relatively impermeable layers, saturating and structurally damaging the bottom of loess layer, ultimately inducing landslides. These findings provide a scientific basis for the future study of loess landslide hazards in different strata structures, which is of great significance.

Investigation on structural and functional behavior of open and dense graded asphalt mixes in mitigating urban floods

Urbanization has led to extensive pavement construction, which, coupled with improper drainage infrastructure, exacerbates urban flooding. Conventional bituminous pavements exacerbate flood risks due to their impermeability, leading to safety hazards and infrastructure damage. To address these challenges, this study investigates the efficacy of Porous Asphalt Concrete (PAC) as a sustainable solution for flood mitigation and pavement durability enhancement. Through laboratory evaluations and flood simulation analyses, the study compares PAC with conventional bituminous mixes in terms of structural, functional, and permeability characteristics. Results indicate that PAC exhibits superior permeability, facilitating effective stormwater management and reducing surface runoff by up to 40%. Furthermore, PAC demonstrates comparable or enhanced performance in Marshall Properties, including stability, flow, and air voids, when compared to conventional mixes. The incorporation of Induction Sensitive Fibers (ISF) enhances pavement durability and moisture resistance, leading to improved tensile strength and reduced abrasion. Binder performance analysis reveals that CRMB-55 exhibits superior stability and durability, making it a promising option for sustainable pavement construction. Flood simulation analyses using QSWAT software demonstrate the effectiveness of PAC in mitigating urban flooding, with notable reductions in surface runoff and discharge. Overall, this research underscores the potential of PAC as a viable solution for sustainable pavement construction, offering both flood mitigation benefits and enhanced pavement durability in urban environments.Graphical

Quantifying the morphology of rock joints and updating the JRC–JCS criterion considering the asperity distribution

Roughness ubiquitously prevails in rock joints and controls the shear behaviours, permeability and damage characteristics of rock joints. A plethora of investigations have focused on the description of joint roughness; however, a detailed method for quantifying joint roughness and evaluating the shear strength has not yet been established. In this study, within the framework of fractal theory, an optical measurement scale was defined to depict the fractal characteristics of joint roughness, and a boundary measurement scale was used to identify first- and second-order asperities. A composite indicator η\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\eta$$\\end{document}, including the fractal roughness coefficient (RD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_{D}$$\\end{document}), the coefficient describing the roughness order (μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu$$\\end{document}) and the anisotropy parameter (λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda$$\\end{document}), was proposed to quantify the surface morphology, which takes the asperity distribution and roughness anisotropy into account. The relationship between η\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\eta$$\\end{document} and JRC was established, and the JRC–JCS criterion was further updated. Moreover, representative examples were given to show the steps required to quantify the morphology of rough joint surfaces with the new quantitative parameter. Direct shear tests were conducted to validate the effectiveness of the proposed method in describing joint roughness and estimating joint shear strength; the results indicate that it is appropriate to use η\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\eta$$\\end{document} to estimate the joint roughness and that the proposed shear strength criterion can appropriately predict the shear strength within an acceptable error.

The Time-Varying Characteristics of Relative Permeability in Oil Reservoirs with Gas Injection

Relative permeability is a critical parameter in reservoir numerical simulation and production prediction, intimately associated with reservoir architecture and fluid property. During gas injection development, substantial alterations in reservoir properties and fluid phase behavior induce dynamic changes in relative permeability. Clearly characterizing the time-varying features of relative permeability is very useful for an understanding of how gas injection influences fluid mobility within the reservoir and enhances recovery rates. In this paper, core displacement experiments are firstly conducted to obtain the characteristics of the relative permeability of oil and gas under various development stages and displacement conditions, further delineating the comprehensive shifts in reservoir properties at different gas injection stages. Subsequently, a novel reservoir numerical simulation method is proposed that considers the spatial and temporal segmentation of relative permeability curves in the reservoir simulation. Finally, a practical application is presented to clarify the effects of injection and production parameters on the development performance of gas flooding oil reservoirs. The results show the following: (i) Significant time-varying characteristics of relative permeability occur throughout gas injection development, in the early stages of gas injection, where most of the reservoir is at the gas injection front, and a rightward shift in relative oil and gas permeability indicates that gas injection promotes oil mobility. Conversely, in the later stages of gas injection, as the reservoir reaches the trailing edge of gas injection, the change trend in relative oil and gas permeability reverses, shifting leftward, thereby exacerbating the gas breakout phenomena. (ii) Increasing the rate of gas injection causes relative oil and gas permeability to move leftward, effectively enhancing the gas volume sweep coefficient and microscopic oil displacement efficiency at lower injection speeds while reducing development performance at higher injection speeds. (iii) An increase in gas injection pressure causes relative oil and gas permeability to shift rightward, and although it reduces residual oil saturation and enhances microscopic oil displacement efficiency, it also intensifies gas breakout phenomena and lowers the gas volume sweep coefficient. This paper provides theoretical guidance and technical support for the design of gas injection strategies, optimization of injection and production parameters, and production forecasting.

Permeability Characteristics of Improved Loess and Prediction Method for Permeability Coefficient

Due to its unique geotechnical properties, loess presents itself as a cost-effective and energy-efficient material for engineering construction, aiding in cost reduction and environmental sustainability. However, to meet engineering specifications, loess often requires enhancement. Evaluating its permeability properties holds significant importance for employing improved loess for construction materials in landfills and artificial water bodies. This study investigates the influence of dry densities, grain size characteristics, grain size distribution, and admixture contents and types on the permeability of improved loess, focusing on the Malan and Lishi loess. The falling head permeability test was conducted to analyze how each factor affects the permeability of the improved loess. The findings indicate that the permeability coefficient decreases with increased dry density and admixture content. Conversely, it demonstrates a linear increase with the average grain size (d50), restricted grain size (d60), and the product of the coefficient of uniformity and coefficient of curvature (Cu × Cc). The primary influencing factor is the type of admixture, followed by Cc and d60. Furthermore, this study developed a predictive model for permeability using a support vector machine (SVM), surpassing the predictive accuracy of linear regression and neural network models. The model provides a robust prediction for the permeability of superior loess material.

Investigating the Impact of Air Permeability and Thermal Properties on Rib Knit Structures

Factors influencing the comfort and performance of knitted fabrics can be investigated to enhance the understanding and development of functional accessories. Issues related to the thermal regulation and moisture management of these materials are systematically explored in this research. Additionally, the effects of fibre type, yarn properties, fabric variables, and finishing methods are examined through the evaluation of physical properties relevant to the comfort of rib knit structures, particularly in sportswear design. 1x1 Rib knit 1structures were created using polyester spun, cotton spun, polyester filament, and viscose filament yarns with varying linear densities employing a KH-323N computerized flatbed knitting machine. Evaluations of physical properties, thermal characteristics, air permeability, antibacterial efficiency, and hydrophilic finish were conducted following ASTM standards and specific testing methods to thoroughly assess the quality and performance of the fabric. Significant insights into the physical and comfort properties of the fabrics were provided by the results. Varying thermal and air permeability characteristics were demonstrated by polyester-cotton and viscose-cotton fabrics. Thermal resistance and conductivity are influenced by filament denier, loop length, and knit structure, while these same factors affect air permeability. Air permeability is also impacted by finishing treatments, thereby highlighting the complex interplay between fabric properties and comfort. Advanced finishing techniques and novel fibre blends could be explored in future research to further optimize fabric comfort properties.

Effect of stress unloading rate on fine-scale deformation mechanism of rock under high osmotic pressure

To explore the influence of the working face excavation rate on the rock deformation mechanism and seepage characteristics, deformation and seepage tests of sandstone under different loading and unloading stress paths, such as constant axial pressure unloading confining pressure and loading axial pressure unloading confining pressure, were carried out. Particle Flow Code in 3 Dimensions (PFC3D) and Python were used to realize fluid-solid coupling, and numerical simulation calculations were performed along the test path to analyze the influence of the unloading rate on the fine-scale deformation mechanism and permeability characteristics of sandstone, and the relationship between crack type and permeability was obtained. A sandstone fracture mechanics model is established to analyze the stress concentration degree at the end of the branch crack of the test path. The results show that the rate of confining pressure unloading is inversely proportional to the strain. Additionally, permeability correlates with the principal stress difference in an exponential manner. Interestingly, the sensitivity of permeability to stress shows an inverse trend with the unloading rate of confining pressure. Furthermore, there exists a linear relationship between permeability and the number of cracks. During the unloading process, tensile cracks predominate, and the propagation of shear cracks lags behind that of tensile cracks. The proportion of tensile cracks decreases with the increase of the unloading rate when the axial pressure is unchanged but increases when axial pressure is added, resulting in axial compression deformation and expansion deformation along the unloading direction. These research outcomes offer theoretical insights for the prudent selection of mining rates, and they hold significant implications for mitigating water inrush disasters in deep mining operations.

Durability and Permeability Characteristics of Consolidated Bodies After Grouting in Freeze–Thaw Rock in Cold Regions

Durability and Permeability Characteristics of Consolidated Bodies After Grouting in Freeze–Thaw Rock in Cold Regions

PBAT/PLA-Based Electrospun Nanofibrous Protective Clothes with Superhydrophobicity, Permeability, and Thermal Insulation Characteristics for Individuals with Disabilities.

This study presents the development of multifunctional protective clothing for disabled individuals using PBAT/PLA biopolymeric-based electrospun nanofibrous membranes. The fabric consists of a superhydrophobic electrospun nanofibrous cloth reinforced with silica nanoparticles. The resulting nanofiber membranes were characterized using FE-SEM, a CA goniometer, breathability and hydrostatic pressure resistance tests, UV-vis spectroscopy, thermal infrared photography, tensile tests, and nanoindentation. The results demonstrated the integration of superhydrophobicity, breathability, and mechanical improvements in the protective clothing. The nanofibrous porous structure of the fabric allowed breathability, while the silica nanoparticles acted as an effective infrared reflector to keep the wearer cool on hot days. The fabric's multifunctional properties make it suitable for various products, such as outdoor clothing and accessories for individuals with disabilities. This study highlights the importance of selecting appropriate textiles for protective clothing and the challenges faced by disabled individuals in terms of mobility, eating, and dressing. The innovative and purposeful design of this multifunctional protective clothing aimed to enrich the lives of individuals with disabilities.