Permeability Of Material Research Articles

The Characteristics of Resin Waste (RW)/Recycled High-Density Polyethylene (R-HDPE) Blends to Enhanced Pavement

Permeable pavement is characterized by open cell structures that enable the drainage of rainfall and snowmelt, as opposed to the runoff observed on impervious pavements. The structural strength of commercial permeable pavement materials is lower than that of conventional pavements due to inherent permeability and structural distinctions. This research focuses on the fabrication of samples using a combination of Resin Waste (RW) and reinforced Recycled High-Density Polyethylene (R-HDPE) in varying ratios of RW (30%, 40%, 50%, 60% and 70% wt/wt). The fabrication process involves a 3-hour heating process at 200°C in a furnace, followed by a 24-hour cure at room temperature. Physical and mechanical properties of the RW/R-HDPE Blends were examined, revealing that the 60% R-HDPE ratio resulted in the lowest density (4.523 g/cm3) and porosity (0.246%). SEM images displayed fewer voids, indicating effective filler dispersion and resin matrix interaction at the 60% resin waste ratio. Tensile strength and stiffness elasticity were maximized at 60% wt/wt of R-HDPE, reaching 3.36 MPa, while the bending strength peaked at 1.1 MPa at the same ratio. The 60% RW/R-HDPE ratio recorded the highest impact strength (26.25 kJ/m2) and energy absorption (1.69 J), showcasing the sample's ability to absorb impact energy through controlled failure mechanisms. In conclusion, the 60% wt/wt RW/R-HDPE Blends exhibit promising potential for enhancing the properties of permeable pavement, particularly in road applications, due to its superior bending and tensile strength.

Study on the effect of hydrogen cycle pressure relief time on the hydrogen permeability and mechanical properties of polyamide liner materials for type IV hydrogen storage cylinders of HFCVs

Plastic liners for type IV hydrogen storage cylinders of hydrogen fuel cell vehicles (HFCVs) experience varying pressure loads, deteriorating both hydrogen permeability and mechanical properties and impacting cylinder safety. This study performs hydrogen cycle tests on polyamide 6 (PA6) and polyamide 11 (PA11) samples (temperature: 288 K; pressure relief times: 6, 60, 3600 s; upper/lower pressure limits: 70/1 MPa). After 50 hydrogen cycles with 60 and 3600 s relief times, PA6 and PA11 exhibit changes in hydrogen permeability coefficients within 2%. However, with a 6 s relief time, the coefficients significantly decrease (>10%). After 6 s cycles, PA6 exhibits tiny holes, while PA11 exhibits clustered pieces of holes. Cracks appear in both materials' internal structures after 60 s cycles. Despite minimal tensile strength changes (within 5%), the nominal strain at tensile fracture of both materials changes significantly under different times. These findings can help determine optimal pressure relief times for hydrogen cycle tests on plastic liners.

Semiflexible spiro-branched membrane with adjustable sub-nanoscale channels and high positive charge for acid recovery

Acid recovery from industrial wastewater based on membrane separation is an essential technology to improve the economic efficiency and environmental friendliness. However, the low recovery efficiency and trade-off between acid permeability and selectivity of membrane materials have hindered the widespread application of this technology. In this study, we developed a spiro-branched membrane with semiflexible three-dimensional (3D) network structure by utilizing rigid contorted units as branching nodes. The semiflexible 3D network structure led to inefficient chain packing and the creation of numerous sub-nanoscale microporous ion channels, with sizes that can be finely adjusted. Furthermore, this 3D network structure allows the membrane to maintain low swelling and excellent stability while being enriched with positively charged groups. Ultimately, the optimally tuned membrane separator demonstrated an outstanding H+ dialysis coefficient (up to 108.6 × 10−3 m h−1), good selectivity (42.2) and high stability, surpassing both commercial membranes and those reported recently.

Investigation of the performance and life cycle assessment of alkali-activated sintered sludge-slag-based permeable concrete

As urbanization continues to accelerate, the application of permeable concrete is becoming an increasingly prevalent practice. Nevertheless, the carbon dioxide emission issue associated with traditional permeable concrete cannot be overlooked. In this study, alkali-activated sintered sludge and slag were employed as raw materials to prepare alkali-activated sintered sludge-slag-based permeable concrete. The effects of sludge calcination temperature, sludge content, and binder-to-aggregate ratio on the compressive strength, porosity, and permeability coefficient of the permeable concrete were investigated through the implementation of one-way experiments. The formation mechanism of permeable concrete materials was analyzed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and a carbon emission assessment was performed. The findings indicated that an increase in sludge content resulted in a notable decline in the 28-day compressive strength, accompanied by a reduction in the Ca/Si ratio of the C-A-S-H hydration products, from 1.08 to 0.35. Conversely, the carbon emission assessment demonstrated that abiotic losses declined markedly with an increase in sludge content, effectively mitigating the carbon emission burden associated with construction materials.

Novel polyethylene glycol methyl ether substituted polysiloxane membrane materials with high CO2 permeability and selectivity

Membrane gas separation is a promising technology for CO2 capture. However, one of the key challenges is the development of stable-in-time and highly permeable materials with increased CO2 permselectivity. In this study, two series of novel polysiloxanes with linear (methyl oligoethyleneglycol allyl ether (PEG8)) and branched (vinyl-bis- [methyltriethyleneglycol] (B-PEG4)) oxygen-containing side substituents were synthesized. By crosslinking PEG-substituted polymethylsiloxanes with polydimethylsiloxane (PDMS), a series of CO2-highly selective membrane materials with a PDMS content of 6.5–50 wt% was obtained for the first time. The effect of the side chain geometry on the sorption and transport properties of these membranes for different gases (N2, O2, CO2, CH4, C2H6) was evaluated. The specific interactions between the PEG substituents and CO2 that contribute to the enhanced selectivity of these materials were identified. The introduction of both linear and branched PEG substituents leads to in an increase in the selectivity of diffusion, solubility, and CO2/gas permeability, compared to PDMS.The CO2/N2 and CO2/CH4 permselectivities and diffusion selectivities are increases, as well as the permeability coefficients of the membrane materials for all gases are decreases, as the PDMS content reduces from 50 % to 6.5 % wt. Within the PDMS concentrations range between 6.5 and 12.5 % wt., there was a sharp increase in diffusion and permeability coefficients of membrane materials. For this polysiloxanes with linear PEG substituents, an unexpectedly high diffusion selectivity for CO2 was observed. Such value determined the maximum CO2 permselectivity among the polysiloxanes studied. The most promising membrane material from these series was identified as PEG8-substituted polysiloxane with 12.5 wt% PDMS. It has a CO2 permeability coefficient of 1300 Barrer, CO2/N2 selectivity of 37 and CO2/CH4 selectivity of 10.

Enhanced Hemodynamics of Anisometric TPMS Topology Reduce Blood Clotting in 3D Printed Blood Contactors.

Artificial organs, such as extracorporeal membrane oxygenators, dialyzers, and hemoadsorber cartridges, face persistent challenges related to the flow distribution within the cartridge. This uneven flow distribution leads to clot formation and inefficient mass transfer over the device's functional surface. In this work, a comprehensive methodology is presented for precisely integrating triply periodic minimal surfaces (TPMS) into module housings and question whether the internal surface topology determining the flow distribution affects blood coagulation. Three module types are compared with different internal topologies: tubular, isometric, and anisometric TPMS. First, this study includes a computational fluid dynamics (CFD) simulation of the internal hemodynamics, validated through experimental residence time distributions (RTD). Blood tests using human whole blood and subsequent visualization of blood clots by computed tomography, allow the quantification of structure-induced blood clotting. The results indicate that TPMS topologies, particularly anisometric ones, serve as effective flow distributors and significantly reduce and delay blood clotting compared to conventional tubular geometries. For these novel TPMS modules, the inner surfaces can be activated chemically or functionalized to function as a selective adsorption site or biocatalytic surface or made of a permeable material to facilitate masstransfer.

An Assessment of the Catalytic and Adsorptive Performances of Cellulose Acetate-Based Composite Membranes for Oil/Water Emulsion Separation.

Cellulose acetate (CA) mixed-matrix membranes incorporating polyvinylpyrrolidone (PVP), bentonite (B or Ben), graphene oxide (GO), and titanium dioxide (TiO2) were prepared by the phase inversion separation technique for oil/water separation. An investigation was performed where the mixed-matrix membrane was tested for the separation performance of hydrophilic and hydrophobic surface properties. An ultrafiltration experiment at the laboratory scale was used to test dead-end ultrafiltration models developed for the treatment performances of oily wastewater under dynamic full-scale operating conditions. Artificial oily wastewater solutions were prepared from hexane, toluene, and engine oil with Tween80 emulsions for oil removal treatment using composite membranes. The impacts of material hydrophilicity, weight loss, permeability, and pore size were investigated, and it was found that the oil retention of membranes with larger pore sizes enabled much more sophisticated water flux. The CA-GO-, CA-B-, and CA-TiO2-incorporated membranes achieved pure water flux (PWF) values of 45.19, 53.41, and 100.25 L/m2h, respectively. The performance of CA-TiO2 in oil/water emulsion rejection was assessed, and the rejection of engine oil/water, toluene/water, and hexane/water mixtures was determined to be 95.21%, 90.33%, and 92.4%, respectively. The CA-based mixed-matrix membrane portrayed better antifouling properties due to enhanced hydrophilicity and water molecules. The CA-TiO2-incorporated membrane possessed the potential to provide high separation efficiency for oily wastewater treatment. This study demonstrates the potential of fine-tuning membrane performances through material hybridization to achieve efficient wastewater treatment.

IFLOW: A Framework and GUI to Quantify Effective Thermal Diffusivity and Advection in Permeable Materials From Temperature Time Series

AbstractiFLOW is a free, open‐source, and python‐based framework and graphical user interface to visualize and analyze temperature time series, and extract one dimensional thermal velocity, vT, and bulk effective thermal diffusivity, ke. Information of thermal properties of the sediment‐water mixture (bulk) and water allows quantifying the one‐dimensional Darcian flux, q, and seepage velocity, v, from vT. Available software packages were developed to quantify q and ke only based on a specific mathematical model or focused on specific data processing or parameter estimation techniques, and all these steps were lumped together preventing users to identify potential source of errors. iFLOW proposes a novel organizational philosophy with a modular framework that parses the analysis process into three fundamental steps: (a) the mathematical model, (b) signal processing, and (c) parameter estimation. iFLOW houses a suite of models and analysis techniques. This suite can be readily added to and expanded through its modular framework. iFLOW contains a wizard to guide users through the selection process with respect to the three fundamental steps. Users can analyze and visualize intermediate results to identify problematic issues in the time series data and improve data interpretation. Here, we present iFLOW and summarize its performance using a set of one‐dimensional synthetic heat transport simulations.

Two-grid reduced-order method based on POD for a nonlinear poroelasticity model

In this paper, we consider a two-field nonlinear poroelasticity model, in which the unknown variables are the solid displacement and the pore pressure, and the permeability of the elastic material depends on the dilatation. A standard Galerkin method based on Picard iteration is presented. To reduce the computational costs, we develop the two-grid method, the reduced-order finite element (ROFE) method based on proper orthogonal decomposition (POD) technique, and a combination of the first two methods, i.e., the two-grid reduced-order finite element (TGROFE) method. The associated numerical error has four components due to the coarse triangulation discretization, fine triangulation discretization, time discretization, and eigenvalue truncation by POD. Numerical experiments show the accuracy and efficiency of these methods. To further illustrate the application of the POD technique to the quasi-static poroelasticity problem, we investigate two reduced-order mixed finite element methods, which avoid pressure oscillations and/or have locking-free property.

Imaging of permeability defect distribution by electromagnetic tomography with hybrid L1 normand nuclear normpenalty terms.

Electromagnetic tomography (EMT), with the advantages of being non-contact, non-invasiveness, low cost, simple structure, and fast imaging speed, is a multi-functional tomography technique based on boundary measurement voltages to image the conductivity distribution within the sensing field. EMT is widely used in industrial and biomedical fields. Currently, there are few studies on the application of EMT in magnetic permeability materials, which makes it difficult to obtain high-quality reconstructed images due to its own properties that lead to obvious attenuation of electromagnetic waves during propagation, as well as the ill-posed and ill-conditioned characteristics of EMT. In this paper, a multi-feature objective function integrating L2 normregularization, L1 normregularization, and low-rank normregularization is proposed to solve the challenge of magnetic permeability material imaging. This approach emphasizes the smoothness and sparsity. The split Bregman algorithm is introduced to efficiently solve the proposed objective function by decomposing the complex optimization problem into several simple sub-task iterative schemes. In addition, a nine-coil planar array electromagnetic sensor was developed and a flexible modular EMT system was constructed. We use correlation coefficient and error coefficient as indicators to evaluate the performance of the proposed image reconstruction algorithm. The effectiveness of the proposed method in improving the reconstruction accuracy and robustness is verified through numerical simulations and experiments.

A comparison study of pore structure and permeability of sandstone by BSE-SE images

The pore structure and permeability of geotechnical materials are critical parameters that guide underground engineering. With advancements in digital imaging technology, scanning electron microscopy (SEM) has emerged as a vital tool for examining the pore structure and permeability of these materials. SEM operates in two primary modes: backscattered electron imaging (BSE) and secondary electron imaging (SE), each of which emphasizes different aspects of the material's structure. However, few studies have been conducted to elucidate the influence of these two modes on the quantification of geotechnical structural characteristics. This study undertakes a more comprehensive quantitative analysis of the structure and permeability of sandstones by juxtaposing the two modes. The findings indicate that the BSE mode excels in analyzing the structure and composition, whereas the SE mode highlights the surface morphology. In terms of image segmentation, BSE mode images are more conducive to effective segmentation. Although SE images permit viable segmentation when preprocessed, they tend to represent a greater number of discrete tiny pores. Furthermore, there exists a discernible correlation between pore size and shape, wherein larger pores exhibit heightened roughness and deviate more from sphericity. Notably, these larger pores predominantly contribute to the material's permeability. Given that the BSE mode more readily captures continuous pore structures, the permeability values derived from BSE images are significantly higher than those obtained from SE images. These findings hold profound implications for enhancing our comprehension of geotechnical materials' pore structure and permeability, thereby informing the strategic use of BSE and SE modes in related studies.

Effect of Curing Time and Ferric Chloride on a Copper Concentrate with a High Arsenic Content

As a result of changes in copper mineralogy, various treatment options for copper sulfides have been explored, including pretreatment processes aimed at enhancing material permeability and improving the dissolution of valuable minerals. Despite its significance, this topic has only recently gained attention. In this research, a copper concentrate with a high arsenic content was studied, with enargite (Cu3AsS4) as the main mineral phase. The objective was to evaluate the effect of pretreatment on copper extraction efficiency prior to leaching. Three key variables were investigated: curing time (0, 5, 10, and 15 days), H2SO4 dosage (0, 70, 140, and 210 kg/t), and FeCl3 concentration (0, 0.5, 1, and 1.5 M). The sample was characterized both before and after pretreatment, revealing the formation of new species such as CuSO4·5H2O and Cu2Cl(OH)3 under optimal conditions of 15 days curing time, 70 kg/t of H2SO4, and 1 M FeCl3. Copper extraction solely through curing reached 20.79%. The analysis suggests that curing time is the most influential factor in the process, accounting for 46% of the overall contribution. In comparison, sulfuric acid and ferric chloride contribute less, with 20% and 10% contributions, respectively.

Gas permeability of partially saturated cement-based materials considering water sensitivity

Gas permeability is a crucial factor influencing the durability of cement-based materials, which are usually in a partially saturated state. This study examines the impact of the water-to-cement (w/c) ratio, water saturation and water sensitivity on the gas permeability of cement-based materials using Nuclear Magnetic Resonance (NMR) and Mercury Intrusion Porosimetry (MIP). The results indicate that the gas permeability of cement-based materials is strongly related to their porosity and pore size distribution. Relative gas permeability is directly influenced by water saturation and the initial state of the materials, with a noticeable hysteresis effect observed. Furthermore, the water sensitivity of cement-based materials results in no evident, but a slight decrease in gas permeability during water saturation.

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.

Modeling of output characteristics of giant magnetostrictive transducer considering temperature and eddy currents

Due to the high conductivity and low permeability of giant magnetostrictive materials (GMMs), eddy currents and temperature rise caused by these materials are unavoidable. These factors will significantly impact the output efficiency and reliability of giant magnetostrictive transducers (GMTs). It is essential to conduct precise evaluations of the output characteristics in various temperature settings to effectively design and optimize the transducer. However, to reduce the eddy current loss of GMMs, a radial slit is introduced. The intricate geometry also contributes to the complexity of analysis. According to the practical engineering requirements, this paper initially established a testing system for GMM characteristic and analyzed the mechanism between material temperature and output characteristics. Second, improvements have been made to the equivalent circuit method. Research has been conducted on the influence of temperature and eddy currents on the electrical and mechanical equivalent circuits, leading to the creation of a comprehensive equivalent circuit model for GMTs. Finally, a testing platform has been set up to assess the temperature-output characteristics of the transducer. The impedance and displacement characteristics of a GMT were examined to validate the proposed model. The test results demonstrated that within the 20 – 100 °C range, the discrepancy between the model and the measured impedance is under 1%, and the displacement amplitude error is less than 5%, thus confirming the precision of the proposed model.

Utilizing the Concept of Entropy in the Second Law of Thermodynamics to Determine Risk Levels Associated with Groundwater and Bottled Drinking Water Using Rainwater Quality as a Clean Reference

The concept of entropy as a state function is employed in this paper within a radiation system designed to address the role of atomic disturbance in determining the levels of physical permeability changes in the studied states, comparing the results with those of a clean phase. This investigation begins with samples prepared for characterization tests using a unique technique for electromagnetic irradiation. The samples included: (1) a rainwater sample carefully collected during the first week of February 2024, serving as a high-quality natural reference in its aqueous phase; (2) a sample from a 42-meter-deep drinking water well (GW) in Ghout al-Dees, west of Tripoli, Libya; and (3) a bottled water sample (AA-WS3) commonly available in the Libyan market. The test results focused on the values of the physical property (τC), identified from the relationship between the entropy operator and time, as a physical fingerprint that accurately detects disturbed material permeability. The study concludes with a section linking the properties of the natural reference phase to the fingerprint characteristics of the studied samples, providing an approach to assess the quality of the tested water samples against the ideal chemophysical quality of rainwater. This led to findings that (1) the groundwater quality (QAA-WS2) was 76.92%, and (2) the quality of bottled water available in the Libyan market (QAA-WS3) was 74.57%, highlighting the role of the polymer composition in plastic container packaging as an additional factor, alongside the structures enclosing water sources, as in the case of the groundwater well exposed to contamination. Keywords: atomic disturbance, entropy, chemical identity, atomic irradiation, wave gaps

Oxygen permeability and gas permeable contact lens materials

In this article, we will examine the importance of oxygen permeability (Dk) in gas permeable contact lens materials, and the significance of high Dk in scleral and ortho-k lens designs.

Permeable Cement Based on Foamed Cement and Permeable Skeleton Materials

Summary Permeable cement has been widely used in the construction industry. In oil fields, the use of permeable cement to replace screens and reduce the cost of well construction has been attempted. However, the compressive strength of permeable cement is low. Herein, a new method for producing permeable cement using foamed cement and permeable microspheres (PMs) is proposed. A permeable cement slurry system is produced by selecting the foaming agent, foam stabilizer, length and dosage of basalt fibers, and permeable skeleton materials (PSMs). The system formula is Jiahua G-grade cement + 1.3% alpha-olefin sulfonate (AOS) + 0.5% xanthan gum (Xg) + 2% nano-SiO2 + 1% 6-mm basalt fiber + 30% PM. The compressive strength and permeability of the permeable cement were tested using compressive strength and hydraulic permeability tests, respectively. The compressive strength of this system could reach 6.6 MPa when it was cured for 2 days at 50°C. Its liquid permeability could reach 0.06×10−3 μm2 when it was cured for 14 days at 50°C.

Zastosowanie Metody Elementów Skończonych do analizy metody określania rozmiaru buta na podstawie pomiarów pola magnetycznego

Paper presents utilization of Finite Element Method (FEM) for analysis of usefulness of shoe size assessment method, based on magnetovision measurements. Measurement method based on disturbances of the uniform magnetic field (e.g. Earth’s magnetic field) is presented. Disturbances are caused by loose material of high magnetic permeability placed inside the tested shoe, which adapts to the insides of the shoe. The disturbed magnetic field is measured by the matrix of magnetometers. The values of magnetic field are an input into inverse transformation algorithm which fits the position of matrix sensors into the reference (obtained by FEM) distribution of magnetic field. Based on the fitted parameters of sensors matrix a ratio between the measured and reference shoe size was determined. A FEM-based forward transformation is presented, which allows for generation of three-dimensional array of magnetic field distribution. Initial tests of inverse transformation were conducted successfully. Next steps consisted of tests of inverse transformation method with an inclusion of the typical measurement noise. A FEM-based forward transformation was conducted of a modified shoe model (including simplified screw model). Inverse transformation was conducted but both influence of measurement noise, as well as the presence of additional high permeability material, resulted that the presented shoe size assessment method is not suitable for practical implementation.

Integrating experimental and theoretical investigations of porous graphite materials with scanning electron microscope image processing

Accurate determination of fractal dimension (FD) and permeability of porous graphite materials (PGM) is essential for applications like porous aerostatic bearings (PABs). This study addresses the need for improved measurement methods by employing image processing and computer vision (IPCV) techniques to enhance FD and permeability accuracy. We aimed to refine these measurements by analysing the effects of image size and magnification on accuracy. The research developed theoretical models based on fractal theory, Darcy's law, and a modified Hagen-Poiseuille gas equation to evaluate these effects. A dual-path X-ray imaging detection system was used for experimental validation. The gauge pressure was varied across the surface of the PGM and volume flow rate was measured. MATLAB was utilized for IPCV, enabling precise FD determination and underscoring the importance of image parameters. Results showed that FD values stabilize at specific image sizes and magnifications, improving accuracy. Linear relationships between pressure gradient and volume flow rate were observed, with permeability stabilizing at high pressures. Porosity values varied among materials: Toyo Carbon (15 %), SGL Graphite (17 %), Super Carbon Graphite (27 %), and poplar porous (30 %). FD obtained through theoretical and scanning electron microscope (SEM) methods had a maximum error of 0.08. The study also found a positive correlation between relative density and image grayscale at the macroscopic level. The findings emphasize the importance of optimizing image size and clarity for accurate PGM analysis, providing crucial insights for PAB design and other advanced applications.