Permeability Test Device Research Articles

Synthesis of Magnesium Oxide Nanoparticles for Fabric Coating and its Antibacterial Activities

Conceptually, the present work leads to the synthesis of magnesium nanoparticles (MgO NPs) using pomegranate (Punica granatum L) rind extract for antibacterial fabric coating. The antibacterial performance of MgO NPs on cotton, polyester and blend wool types of fabric was evaluated towards three species of gram-positive bacteria; Staphylococcus epidermidis, Brevibacterium linens and Cutibacteriumacnes. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the successful of sol-gel synthesis process with the presence of flavonoid compounds in MgO NPs solution. The breaking load test was run for all fabric samples, while for tearing strength test, it was carried out only for cotton and polyester fabrics. Air permeability test device was used to determine the air permeability of all fabric samples to ensure the ventilation of the fabrics after coating process. The MgO NPs produced from sol-gel synthesis method established a good antibacterial activity against gram-positive bacteria in all types of fabric samples.

Research on heat transfer model of air permeability test device for food and drug soft packaging materials

The air permeability test of food/drug packaging materials such as plastic film and plastic sheet is indispensable in the process of sealing and preservation. During film permeability testing, a constant temperature environment needs to be maintained. In order to obtain satisfactory thermostatic control and reduce the influence of ambient temperature on test results, it is necessary to explore the heat transfer model of the permeability testing device. Firstly, the experimental platform is constructed with a Thermo Electric Cooling as the heat source and a thermometer as the temperature measurement element. Then, the three-dimensional heat transfer model of the food and drug soft packaging material permeability testing device was established, and the analytical solution of the temperature distribution function was obtained. Finally, the simulation and test results show that the proposed model is consistent with the experimental test results, and the model errors caused by the heat insulation or heat dissipation of the device can be ignored. This work provides a theoretical basis for further research on the air permeability test of soft packaging materials.

Evolution of pore-fracture structure and permeability of coal by microwave irradiation under uniaxial compression

In a natural coal reservoir environment, the coal seam is constrained by in-situ stress and gas pressure. Damage on the coal microstructure due to microwave irradiation (MI) differs significantly different from that under no-load conditions. In this study, the effect of MI on the pore-fracture structure and seepage characteristics of load-constrained coal is investigated using a custom-developed microwave fracturing experimental device, nuclear magnetic resonance test device, and permeability test device. Based on the relationship between microwave and pore-fracture structure parameters and the permeability of loaded coal, the pore-fracture structure evolution and permeability growth law of loaded coal under MI are determined. The results show that the number of micropores in coal decreases and the T2 curve of micropores is shifted to the right under the combined effect of MI and external stress load. The numbers of mesopores, macro-pores, and micro-fractures increase, and the T2 curve exhibits a broader peak span. The pore-fracture structure evolution effect of loaded coal increases with the microwave power and MI time. Under high-power MI, the pore-fracture structure evolution of the loaded coal shows a “decrease - increase – decrease” trend as the stress load increases, whereas a “decrease – increase” trend is shown under low-power MI. Under the same microwave parameters, the permeability of unloaded and loaded coal increases by a maximum of 15.7 and 364.7 times, respectively. In particular, the permeability increases by 3.1–11.4 and 17.8–49.7 times under external stress loads of 4 and 2 MPa, respectively. The combination of high MI power and short MI duration under the same microwave energy facilitates the development of the pore-fracture structure and increases the permeability of loaded coal. Microwaves have a differential thermal effect on mineral in coal, which reduce the physical properties of the coal. Pore-fracture structure and permeability are further enhanced by the stress load.

Study on Pyrolysis-Mechanics-Seepage Behavior of Oil Shale in a Closed System Subject to Real-Time Temperature Variations.

In situ mining is a practical and feasible technology for extracting oil shale. However, the extracted oil shale is subject to formation stress. This study systematically investigates the pyrolysis–mechanics–seepage problems of oil shale exploitation, which are subject to thermomechanical coupling using a thermal simulation experimental device representing a closed system, high-temperature rock mechanics testing system, and high-temperature triaxial permeability testing device. The results reveal the following. (i) The yield of gaseous hydrocarbon in the closed system increases throughout the pyrolysis reaction. Due to secondary cracking, the production of light and heavy hydrocarbon components first increases, and then decreases during the pyrolysis reaction. The parallel first-order reaction kinetic model shows a good fit with the pyrolysis and hydrocarbon generation processes of oil shale. With increasing temperature, the hydrocarbon generation conversion rate gradually increases, and the uniaxial compressive strength of oil shale was found to initially decrease and then increase. The compressive strength was the lowest at 400 °C, and the conversion rate of hydrocarbon formation gradually increased. The transformation of kaolinite into metakaolinite at high temperatures is the primary reason for the increase in compressive strength of oil shale at 400–600 °C. (ii) When the temperature is between 20 and 400 °C, the magnitude of oil shale permeability under stress is small (~10−2 md). When the temperature exceeds 400 °C, the permeability of the oil shale is large, and it decreases approximately linearly with increasing pore pressure, which is attributed to the joint action of the gas slippage effect, adsorption effect, and effective stress. The results of this research provide a basis for high efficiency in situ exploitation of oil shale.

Experimental Study to Quantify Fracture Propagation in Hydraulic Fracturing Treatment.

Hydraulic fracturing plays an important role in the commercial development of unconventional oil and gas, which is directly related to the production of oil and gas wells. An accurate evaluation is critical for hydraulic fracturing, but it is urgent to propose a quantitative assessment of hydraulic fracturing fracture propagation for realizing hydraulic fracturing fracture propagation and multiposition permeability measurement under an in situ stress environment. Herein, a true triaxial stress loading and permeability testing device was designed and fabricated, and a permeability evaluation model was established under various states, which can realize the accurate measurement of multiple faces and the total permeability of tight specimens before and after hydraulic fracturing. It can directly measure permeability under the conditions of the true triaxial fracture propagation experiment. The comparative experimental result shows that the new technique can quantitatively evaluate the fracture propagation experiment of true triaxial hydraulic fracturing. The overall permeability and the directional permeability of the five faces were obtained, and the fracture propagation was evaluated by comparing the change in permeability. The test permeability error rate is within ±10%. Furthermore, a more refined evaluation of hydraulic fracturing fracture propagation can be carried out based on the fracture observation and AE event results. The research results provide a new strategy for a more quantitative and refined evaluation of fracture propagation and help to optimize the parameters of hydraulic fracturing.

The Application of Breakthrough Pressure in the Evaluation of the Sealing Ability of Cement–Casing Interface and Cement Matrix in Underground Gas-Storage Wells

This paper proposes an evaluation system for the sealing ability of cement–casing interface and cement matrix, which was developed based on a permeability testing device and a model that predicts the breakthrough pressure of cement sheath matrix and interfacial transition zone (ITZ). It was found that the breakthrough pressure of ITZ was much smaller than that of cement matrix. Moreover, compared with water-based drilling fluid, oil-based one led to lower breakthrough pressure of ITZ even after the flushing treatment. Meanwhile, latex, resin and elastic materials enabled a substantial rise in the breakthrough pressure of cement matrix. However, compared with the latex, resin and elastic cement, the expansive cement had higher breakthrough pressure of ITZ, indicating an improvement on the interface sealing ability. Additionally, a small enlargement rate of the hole diameter and long effective bond were able to prevent gas storage wells from leakage.

Effects of Nonaqueous Phase Liquids Pollution on the Permeability and Microstructure of In-Filed and Laboratory Soaked Contaminated Clay Soils

The fact that the permeability and microstructure properties of clay will be changed by NAPL (Nonaqueous Phase Liquids) pollution draws high attention in the study of the interaction between NAPL and contaminated soil. Through in-field contaminated clay soils from vinyl chloride and 1, 1, 2-trichloroethane-contaminated site in Shanghai, the variation of the content of vinyl chloride and 1, 1, 2-trichloroethane pollutants in clay with depth was obtained. The change of plasticity, permeability, and microstructure properties of the clay samples contaminated by vinyl chloride and 1, 1, 2-trichloroethane were investigated in detail. The measured test results were compared with the uncontaminated clay and indoor soaked contaminated clay samples by TCE (Trichloroethylene). The test results showed that the microstructure characteristics of clay were changed under the influence of the content of TCE, vinyl chloride, and 1, 1, 2-trichloroethane. The total porosity, accumulative pore volume, and the content of the macroporosity percentage of clay soils showed an increasing trend. The flocculation structure of contaminated clay samples was observed, but there were no overhead pores and connected cracks. Volatile organic pollutants were detected in both field and indoor contaminated clay samples. The plastic limit and liquid limit of each layer of contaminated samples decreased slightly, the plastic index did not change significantly, and the pore ratio and permeability coefficient increased gently. At the same time, the clay shrinkage was aggravated by TCE pollution, and cracks appeared on the surface of soil samples. However, no connected cracks were formed. Test results indicated that the self-developed improved permeability test device can be used to test the permeability coefficient of clay samples with shrinkage and to crack by NAPL pollution. The permeability coefficient showed an increasing trend, though the increase was not at the level of magnitude.

Experiment and model study of gas preferential penetration of municipal solid waste

Municipal solid waste (MSW) has various components, different sizes and strong heterogeneity. The significant preferential flow effect of MSW directly affects the migration path of landfill gas. Laboratory tests on the gas breakthrough curve of MSW under the influence factors of initial pressure and moisture content were carried out by self-developed gas permeability test device. The experimental results showed that the peak value of gas breakthrough curve increased gradually with the increase of initial pressure, and increased with the increase of moisture content. A mathematical model for describing gas migration in the macro-porous region and the fractured region was established based on the theory of pore-fracture seepage in porous media. The whole process of gas passing through the MSW sample was simulated. The simulation results showed that the higher the ratio of permeability between the crack and the pore, the greater the peak value of gas breakthrough curve, and the shorter the time of gas passing through the sample. As the proportion of fractured area in pore space decreased, the peak value of gas breakthrough curve decreased gradually.

Determination of the permeability coefficient and airflow resistivity of nonwoven materials

Air penetration behavior plays a vital role in the performance of fibrous material in various industrial applications. Two parameters, the permeability coefficient and airflow resistivity, can describe the air penetration behavior of fibrous material. FX 3300 Textech Tester III and AFD300 AcoustiFlow devices were used to respectively characterize the permeability coefficient and airflow resistivity of nonwoven materials. Nonwoven samples were compressed due to the load from the test head of the FX 3300. Finite element analysis along with the mathematical method were implemented to recover the airflow permeability of samples at the uncompressed state. The effects of pressure drop on the airflow velocity and permeability coefficient were analyzed by the Ergun-type model. The determination of airflow resistivity based on the permeability coefficient is carried out via two approaches, that is, the direct method and the extrapolation method. The results show that the airflow velocity is not linearly related to the pressure drop, which differs from Darcy's law. This non-linear relation is mainly attributed to the influence of frictional loss. By comparing the relative error between assessed and measured airflow resistivity, most of the assessed values of the compressed samples are overestimated. The results also suggest that the direct and extrapolation methods are applicable to assess airflow resistivity on an airflow velocity (or air permeability) test device. Moreover, the Ergun-type model is also applicable to determine the permeability coefficient and airflow resistivity of nonwoven materials.

Air permeability of biochar-amended clay cover

Biochar has a porous structure with high specific surface area and high adsorption. Moreover, it provides a suitable habitat for microorganisms that can reduce harmful gases. Adding biochar to a traditional landfill clay cover (i.e., biochar-amended clay cover) can increase soil porosity, improve soil air flow, and reduce landfill methane emissions which are an area of interest for many researchers. In the present research, the air permeability of biochar-clay is considered to be the main measure in evaluating the fluid-flow characteristic of the material. We discussed the influence of biochar content and particle size on air permeability of biochar-clay and its mechanism. The air permeability coefficient ka of biochar-clay mixture with different biochar content (0%, 5%, 10%, 15%, and 20%), dry densities (1.42 g/cm3, 1.56 g/cm3, and 1.65 g/cm3), and biochar particle size ranges ( 74 μm) were measured using a flexible wall air permeability testing device. Changes in soil pore structure were analyzed by scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). The results show that when dry density was 1.42 g/cm3, the air permeability coefficient decreased as the biochar content increased. For biochar-clay mixture of 1.56 g/cm3 and 1.65 g/cm3, when the biochar content was 15%, the air permeability coefficient of biochar-clay mixture reached its lowest value. Comparing the air permeability coefficient of biochar-clay mixture with non-intersecting particle size groups of biochar, it was revealed that the permeability coefficient decreased as the biochar particle size decreased. Based on the pore structure of biochar-clay mixture with different biochar content and particle size, the influence biochar content and particle size on the air permeability was evident.

Drainage Capacity and Resistance to Clogging of Porous Asphalt Concrete Based on the Water Penetration Test and Constant Head Permeability Test

Abstract Porous asphalt concrete (PAC) can decrease the risk of hydroplaning, reduce splashing and spraying, improve visibility, reduce traffic noise, and improve driving safety, but the clogging of the void affects its durable function. To investigate this, the fine aggregate was chosen as a plugging agent, and the permeability coefficients and water permeability coefficients were measured by using an asphalt mixture permeability testing device and pavement surface permeameter to simulate a multicycle drainage clogging experiment of PAC. The influence of asphalt mixture design parameters, including voids volume (VV), the nominal maximum aggregate sizes (NMASs), grading types on the drainage capacity, and resistance to clogging, was investigated. The two test results indicated that VV has a manifest influence on both drainage capacity and resistance to clogging. The NMAS has an obvious influence on resistance to clogging but no clear influence on the drainage capacity. PAC with the coarser gradation has better performance on drainage capacity and resistance to clogging. The clogging location is concentrated on the top 40 mm of the PAC-13 specimen. The fine particles with diameters of 0.15 to 2.36 mm are the key particles causing the clogging in the PAC-13 specimen. Water permeability coefficients and permeability coefficients have a very high correlation.

Effect of inherent anisotropy on transverse permeability of porous functional asphalt mixtures

In order to study the effect of inherent anisotropy on transverse permeability of porous asphalt mixtures, the transverse permeability performance in different directions of eight kinds of graded porous asphalt mixtures was studied by using the self-made transverse permeability test device of rutting specimen. At the same time, the study combined the grey relation theory, and the influence of the key sieve passing rate on the transverse permeability performance of porous asphalt mixtures is investigated based on inherent anisotropy. The results show that with the increase of the air voids content and the nominal maximum particle size, the transverse permeability coefficient of the rutting specimen increases gradually. The fitting degree of inherent anisotropy can be improved by increasing the nominal maximum particle size and air voids content of asphalt mixtures. The coefficient of variation decreases rapidly when the non-rolled surface is used as the permeable surface. The results of grey correlation analysis showed that the most influential sieve passing rate for the coefficient of variation of OGFC-13 are the 4.75 mm and 1.18 mm, and OGFC-16 are the 2.36 mm and 4.75 mm. For the grey correlation degree of the key sieve passing rate to the coefficient of variation, the OGFC-13 is larger than OGFC-16. The void distribution is uneven for the same rutting specimen surface and the uneven degree of the void distribution in the rolled surface is large.

Effect of natural oxide film on the deuterium permeation behavior of 430 stainless steel

The deuterium permeation behavior of palladium-coated 316L stainless steel and 430 stainless steel was studied by the gas permeability testing device in this study. The results show that the deuterium permeability of the palladium-coated 316L stainless steel tested at 350 °C∼650 °C was very close to the Forcey’s results. This way, the conformity to some other reported results has been verified for the gas permeability testing device. The deuterium permeability for the oxidized 430 stainless steel was compared with that for the palladium-coated 430 stainless steel at temperature range of 350 °C–600 °C. The deuterium permeability for the oxidized 430 stainless steel was reduced by one order of magnitude compared with that for the palladium-coated 430 stainless steel. However, the activation energy of deuterium permeation as gas form for the oxidized 430 stainless steel was almost the same as that for unoxidized 430 stainless steel.

Numerical Simulation and Experiment Study on the Characteristics of Non-Darcian Flow and Rheological Consolidation of Saturated Clay

To investigate the characteristics of the non-Darcian water flow through saturated clay and one-dimensional rheological consolidation behaviors of the soil in the Henan Province, we conducted constant-head permeability and one-dimensional rheological consolidation tests with one-way drainage using improved permeameter and oedometer tests, respectively. We then used Hansbo’s flow equation to classify the permeability test results and one-dimensional rheological consolidation equation combined with unified hardening (UH) constitutive model considering time effect was introduced to simulate the oedometer test results. The obtained results showed that the improved constant-head permeability test device was suitable for saturated clays, and that the UH constitutive model and Hansbo’s flow equation had good applications for the saturated clays investigated in this experiment.

Experimental Study on Compression and Intrinsic Permeability Characteristics of Municipal Solid Waste

Compression and gas permeability characteristics of municipal solid waste (MSW) are of great significance to the design, construction, management, and operation of landfill. The objective of this paper was to study the compression and gas permeability characteristics of MSW. A compressing test device and gas permeability test device for MSW were introduced, and laboratory tests were carried out. The test results showed that the final strains at the vertical loads of 100 kPa, 200 kPa, 300 kPa, and 400 kPa were 35.8%, 45.1%, 49.2%, and 55.1%, respectively. The natural logarithm of void ratio and pressure was linearly correlated at different times. Intrinsic permeability measured without considering gas compressibility was smaller than that measured with considering gas compressibility. Intrinsic permeability of MSW decreased with the increase of the inlet pressure. It was suggested that the inlet pressure should be set to 3 kPa for the indoor gas permeability test of MSW. Intrinsic permeability of MSW decreases with the increase of water content and compression displacement. Power function and logarithmic model were suitable for the fitting of permeability and porosity of manually prepared fresh MSW samples, while the K‐C model was not suitable. With the increase of moisture content, the coefficient and power index of the power function model decreased gradually. And the slope and intercept of the double logarithmic model also decreased gradually with the increase of moisture content.

Fuel permeability of anion exchange membranes under electric field

The development of membranes with high ionic conductivity and low fuel permeability is a key for the fuel cell researches. However, the understanding of the fuel permeability in an operating cell is far from clear. In this work, a fuel permeability test device under the electric field was established for the first time to simulate the actual permeation of fuel across the anion exchange membranes (AEMs) during operating. Two kinds of AEMs (blank AEM and Co-AEM) were tested to investigate the effects of electric field and membrane component on the fuel permeability of the membranes. The Co-AEM showed much higher ionic conductivity and little lower fuel permeability than the blank AEM without electric field. As the electric field increased, the fuel permeability of the blank AEM continuously increased while that of the Co-AEM gradually decreased. The different change of the fuel permeability between the blank AEM and the Co-AEM resulted from the catalytic effect of Co-species which promoted the hydrolysis and electrical oxidization of borohydride. The high ionic conductivity and low fuel permeability of the Co-AEM, especially under electric field, resulted in the low polarization rate of cathode and high power density of the direct borohydride fuel cell using the Co-AEM.

Laboratory determination of hydraulic anisotropy of dense graded asphalt concrete

Dense graded asphalt concrete is widely used in roads as support structure for vehicle loads, however, is also used for hydraulic purposes in canal linings as well as faces and cores of dams. In the design stage of these constructions it is necessary to have the permeability data of the materials that will be used and, although in some cases it is sufficient to know this parameter in only one direction, in others it is necessary to have it in two directions. This research presents test results of axial permeability in constant head permeameter and the design a of radial permeability test device in asphalt concrete made for hydraulic purposes. As a result it was determined that the compaction process of asphalt concrete, applied in one direction, causes the material to have anisotropic behavior from the hydraulic point of view, resulting in anisotropy ratios 7.1 to 10.4, for the studied asphalt mixture.

Permeability Test Device for Soil with Automatic Water Head Control

This paper proposes a constant water head permeability test device for soil with automatic water head control using sensors, actuators, and a microcontroller. A microcontroller controls a solenoid valve based on signals from a water level sensor to sustain a constant water level. The microcontroller also uses a digital scale, a temperature sensor, and a digital time clock to measure the amount of water, water temperature, and time lapse, respectively, during a permeability test. In the permeability tests for Jumunjin sand and Gwanak weathered soil that were performed in this study, the test device sustained a constant water level, minimizing the wastage of water. The permeability coefficients determined using the developed device were practically identical to the permeability coefficients obtained from the conventional method and had good agreement with the predicted values from previous studies. This study is also expected to well showcase the improvement and automation of the conventional geotechnical experiments using the microcontroller.

Determination of Air Permeability Property of Air-Laid Nonwoven Fabrics Using Regression Analyses

Air-laid nonwoven fabrics are generally used for hygienic care products such as diaper, adult nappy and sanitary napkins. Air permeability is one of the foremost properties that affect the usage performance of these hygienic care products. In this study, 10 different air-laid nonwoven fabric samples are produced. The porosity ratios of these samples are determined by digital image processing methods. Air permeability of the samples is tested by digital air permeability test device. Then regression analyses were applied to the experimental results using SPSS 21.0 package program. Finally regression equation was obtained for prediction of air permeability by using porosity, thickness and fabric weight.

Fabrication and characterization of novel biomimetic alveolar clusters

Event Abstract Back to Event Fabrication and characterization of novel biomimetic alveolar clusters Daichi Kasai1, Lanxin Lyu1 and Ying Yang1 1 Keele University, Institute of Science and Technology in Medicine, United Kingdom Introduction: The lung is the essential respiration organ in many air-breathing animals with principal function of gas exchange between atmosphere and bloodstream. However, because of the lung cancer, chronic/acute inflammation, and other disease in lung, the function of lung will get irreversible destruction. Many techniques have been employed to reconstruct lung, such as hydrogel scaffolds[1], decellularized lung[2]-[4], while there is no perfect scaffold yet that can lead to biomimic alveoli. In this study, we generated biomimetic alveolar clusters through using inverse opal 3D scaffolds which have uniform pore structure, better gas permeability and mechanical property. The capacity of blood capillary forming in the cluster was also tested by co-culturing of epithelial cells and endothelial cells. Materials and Method: Polyurethane (PU) and poly(L-lactic acid) (PLLA) inverse opal 3D scaffolds (IOS) were fabricated to mimic alveolar cluster[5]-[7]. PU and PLLA porous scaffolds by NaCl salt leaching method (SLS) were also generated as the control. Compression test was done to evaluate the mechanical property of IOS and SLS. We designed a new facile gas permeability testing device using a syringe pump and detergent film of which weight and friction can be negligible[8]. The rate of detergent film was recorded to evaluate the gas permeability qualitatively. Epithelial cells (NL20) labelled by PKH26 cell linker and endothelial cells (HUVECs) were seeded into the VEGF grafting scaffolds (IOS and SLS) sequentially. Cell viability was tested by CCK-8 kits and cell location was observed directly by confocal microscope. CD31 staining was used to demonstrate the location of HUVECs. Results and Discussion: PU-IOS with pore diameter of 185μm, 240μm, 310μm, 432μm and PU-SLS, PLLASLS with pore size of 250-350μm were fabricated. The compression test showed that the Young’s modulus of PU-IOS were around 0.1MPa, which was much softer than PU-SLS but close to the modulus of alveolar. Under the optimized gas perfusion rate, the new gas permeability device showed sensitive measurement of gas permeability for the porous scaffolds. From the gas permeability test it can be seen that the gas permeability of PU-IOS was much better than PU-SLS and PLLA-SLS (Figure 1). The CCK-8 results showed that there were higher cell number in PU-IOS scaffolds than PU-SLS or PLLA-SLS. Confocal images conformed that cells were attached predominantly outside the scaffold than inside as the diameter of the pore of PU-IOS became larger. Within two week culture, NL20 became elongated, communicating with adjacent cells to form a sheet-structure in IOS scaffold. CD31 staining results showed that after 22 day culture, HUVECs became elongated as well in the inverse opal scaffolds, and co-localization with NL20 cells (Figure 2), while on PU-SLS and PLLA-SLS scaffolds, HUVECs and the epithelial cells showed rounded shape. Figure 1 The mechanical test results (A); the gas permeability test results, (B) and (C). Figure 2 Co-localization of NL20 and HUVECs on different scaffolds. PU-IOS with pore diameter of 185 μm (A1 and A2), 240 μm (B1 and B2): PU-SLS (C1 and C2), and PLLA-SLS (D1 and D2). A1-D1: PKH26 cell linker showing the NL20 location; A2-D2: CD31 staining showing the location of HUVECs. Conclusion: This study demonstrates that PU-IOS scaffolds can lead to biomimetic alveolar clusters with outstanding mechanical property and gas permeability, also good surface property for epithelial and endothelial cells attachment and proliferation, which could be a good candidate for lung tissue engineering.