Research on the Relationship between Permeability and Pore Size Characteristics of Microporous Nonwoven Geotextile

2013 ◽  
Vol 753-755 ◽  
pp. 792-797 ◽  
Author(s):  
Bing Xuan Ni ◽  
Peng Zhang
Keyword(s):  
Pore Size ◽  
Pore Diameter ◽  
Average Pore Diameter ◽  
Flow Index ◽  
Hydraulic Permeability ◽  
Measuring Instrument ◽  
Average Pore ◽  
Vertical Permeability ◽  
Nonwoven Geotextile ◽  
The Relationship

The hydraulic permeability performance of geosynthetics is an important functional technical index in the field of engineering application. In this paper, the pore size characteristics of a series different specifications of spunbond and needlepunched nonwoven geotextile has tested through capillary flow aperture measuring instrument, including average pore diameter, maximum pore size and pore size distribution. The permeability characteristics of nonwoven geotextile has measured by vertical permeability measuring instrument, including flow index and vertical permeability coefficient. We study on the compressive properties of nonwoven geotextile under the different pressure, through the relationship between the average pore diameter and flow index to fit curve, and built the regression equation, so we can calculate and predict the water permeability performance through pore size Characteristics.

How to tailor the porous structure of alumina and aluminosilicate gels and glasses

1996 ◽  
Vol 11 (2) ◽  
pp. 518-528 ◽  
Author(s):  
V. Vendange ◽  
Ph. Colomban
Keyword(s):  
Porous Structure ◽  
Pore Structure ◽  
Pore Size ◽  
Boron Oxide ◽  
Pore Diameter ◽  
Average Pore Diameter ◽  
Mesoporous Aluminosilicates ◽  
Average Pore ◽  
Impregnation Process ◽  
Size And Structure

Optically clear monolithic (OCM) gels of mesoporous aluminosilicates (average pore diameter 3.6 nm) and alumina (6 nm) have been prepared by slow hydrolysis-polycondensation of alkoxides and converted into OCM mesoporous glasses by heating. In order to change the properties, different ways of modifying the pore size and structure are proposed. We show that addition of boron oxide reduces the average pore diameter. A higher effect can be obtained by addition of a surfactant. In this case the mesoporous matrix becomes microporous (d < 2 nm). Another way of modifying the pore structure consists of introducing nanoprecipitates inside the porosity by an impregnation process. Modifications of the porous structure are different in alumina and aluminosilicates.

scholarly journals Experimental Study of the Independence of Diffusion and Hydrodynamic Permeability Coefficients in Collodion Membranes

1960 ◽  
Vol 43 (3) ◽  
pp. 523-532 ◽  
Author(s):  
Elliott Robbins ◽  
Alexander Mauro
Keyword(s):  
Experimental Study ◽  
Permeability Coefficient ◽  
Pore Diameter ◽  
Irreversible Thermodynamics ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Flux Data ◽  
Two Parameters ◽  
The Relationship ◽  
Hydrodynamic Permeability

The two parameters usually invoked when discussing transport across membranes are the "diffusion permeability coefficient" and the "hydrodynamic permeability coefficient." In this study the magnitude of these two coefficients is established experimentally for collodion membranes of differing porosities. The hydrodynamic permeability is predominant while convergence of the two permeabilities tends to obtain as the membranes become less coarse. The flux data obtained are used to calculate "average pore diameter" and the meaningfulness of these calculations is interpreted. The relationship between the two coefficients and transport across membranes as treated by the system of irreversible thermodynamics is discussed.

scholarly journals Relationship between the Shear Strength and Microscopic Pore Parameters of Saline Soil with Different Freeze-Thaw Cycles and Salinities

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1709
Author(s):  
Jiaqi Wang ◽  
Qing Wang ◽  
Sen Lin ◽  
Yan Han ◽  
Shukai Cheng ◽  
...  
Keyword(s):  
Shear Strength ◽  
Pore Structure ◽  
Pore Diameter ◽  
Saline Soil ◽  
Soil Samples ◽  
Average Pore Diameter ◽  
Failure Strength ◽  
Average Pore ◽  
Freeze Thaw ◽  
The Relationship

Saline soil is a widely distributed special soil with poor engineering properties. In seasonally frozen regions, the poor properties of saline soil will cause many types of engineering damage such as road boiling, melt sinking, and subgrade instability. These engineering failures are closely related to the shear strength of saline soil. However, there are relatively few studies on saline soil in cold regions. The strength of the soil is always determined by its microstructure; therefore, the study aims to investigate the relationship between the shear strength and microscopic pore structure of saline soil with different freeze–thaw cycles and salinities. The shear strength characteristics of saline soil with different salinities subjected to different freeze–thaw cycles were obtained by triaxial tests. In addition, the microstructure of the soil samples was investigated by scanning electron microscopy (SEM) tests, and the microscopic pore parameters of the soil samples, including porosity (N), average pore diameter (D¯), average shape coefficient (K), surface fluctuation fractal dimension (F), and orienting probability entropy (Hm), were obtained by image processing software quantitatively. Based on the experimental results, the influence of freeze–thaw cycles and salinity on the shear strength characteristics and microstructure of the soil samples were analyzed. Besides that, in order to effectively eliminate the collinearity between independent variables and obtain a stable and reasonable regression model, principal component regression (PCR) analysis was adopted to establish the relationship between the microscopic pore parameters and the failure strength of the soil samples. The fitting results demonstrated that the failure strength of saline soil is mainly related to the size and direction of the pores in the soil, and it has little correlation with pore shape. The failure strength of the soil was negatively correlated with the average pore diameter (D¯) and porosity (N), and it was positively correlated with the orienting probability entropy of the pores (Hm). This study may provide a quantitative basis for explaining the variation mechanism of the mechanical properties of saline soil from a microscopic perspective and provide references for the symmetry between the changes of the macroscopic properties and microscopic pore structure of the saline soil in cold regions.

Diffusion of Heavy Oil in SiO2 Model Catalyst and FCC Catalyst

2012 ◽  
Vol 550-553 ◽  
pp. 158-163 ◽  
Author(s):  
Zi Yuan Liu ◽  
Sheng Li Chen ◽  
Peng Dong ◽  
Xiu Jun Ge
Keyword(s):  
Diffusion Coefficient ◽  
Pore Size ◽  
Effective Diffusion Coefficient ◽  
Pore Diameter ◽  
Effective Diffusion ◽  
Model Catalyst ◽  
Average Pore ◽  
Diffusion Factor ◽  
Fcc Catalyst ◽  
Fcc Catalysts

Through the measured effective diffusion coefficients of Dagang vacuum residue supercritical fluid extraction and fractionation (SFEF) fractions in FCC catalysts and SiO2model catalysts, the relation between pore size of catalyst and effective diffusion coefficient was researched and the restricted diffusion factor was calculated. The restricted diffusion factor in FCC catalysts is less than 1 and it is 1~2 times larger in catalyst with polystyrene (PS) template than in conventional FCC catalyst without template, indicating that the diffusion of SFEF fractions in the two FCC catalysts is restricted by the pore. When the average molecular diameter is less than 1.8 nm, the diffusion of SFEF fractions in SiO2model catalyst which average pore diameter larger than 5.6 nm is unrestricted. The diffusion is restricted in the catalyst pores of less than 8 nm for SFEF fractions which diameter more than 1.8 nm. The tortuosity factor of SiO2model catalyst is obtained to be 2.87, within the range of empirical value. The effective diffusion coefficient of the SFEF fractions in SiO2model catalyst is two orders of magnitude larger than that in FCC catalyst with the same average pore diameter. This indicate that besides the ratio of molecular diameter to the pore diameter λ, the effective diffusion coefficient is also closely related to the pore structure of catalyst. Because SiO2model catalyst has uniform pore size, the diffusion coefficient can be precisely correlated with pore size of catalyst, so it is a good model material for catalyst internal diffusion investigation.

Pore Structure and Mechanical Properties of ZrC/SiC Multi-Components Modified C/C Composites

2013 ◽  
Vol 833 ◽  
pp. 159-164 ◽  
Author(s):  
Xiu Qian Li ◽  
Hai Peng Qiu ◽  
Jian Jiao
Keyword(s):  
Mechanical Properties ◽  
Pore Diameter ◽  
Testing Machine ◽  
Average Pore Diameter ◽  
Flexural Properties ◽  
Matrix Interface ◽  
Polymeric Precursor ◽  
Average Pore ◽  
Fiber Matrix Interface ◽  
Injection Apparatus

The ZrC/SiC multi-components modified C/C composites were prepared by using a hybrid precursor containning polycarbosilane and organic zirconium-contained polymeric precursor as impregnant and C/C composites of low density as preform. The porosity, microstructure and mechanical properties of samples were characterized with mercury injection apparatus, scanning electron microscopy and universal electron testing machine respectively. The results show that the porosity and average pore diameter decrease firstly and increase subsequently with the increase of organic zirconium content of the precursor. When the content of organic zirconium is 50%, the porosity and average pore diameter reach minimum which were7.27% and 0.0795um respectively. The most probabilistic pore diameter shifted from 10-100um to 1-10um at the same time; Meanwhile, the flexural properties also increases and drops immediately as the content of organic zirconium in the precursor adds. When the content of organic zirconium is 25%, the flexural strength reaches maximum of 245.20MPa.The improved flexural properties is attributed to the proper bonding of fiber-matrix interface and the low porosity of samples.

Added-value porous materials for controlled thymol release obtained by supercritical CO2 impregnation process

2019 ◽  
Vol 38 (5-6) ◽  
pp. 153-166 ◽  
Author(s):  
Stoja Milovanovic ◽  
Darka Markovic ◽  
Jasna Ivanovic
Keyword(s):  
Pore Diameter ◽  
Operating Time ◽  
Zero Order ◽  
Average Pore Diameter ◽  
Added Value ◽  
Average Pore ◽  
First Order ◽  
Supercritical Impregnation ◽  
Bioactive Substance ◽  
Environmentally Friendly Process

This study explores utilization of biodegradable and biocompatible polymers for controlled release of natural bioactive substance. For that purpose, poly(ε-caprolactone) (PCL) beads, cellulose acetate (CA) film, and poly lactic- co-glycolic acid (PLGA) flakes were impregnated with thymol by employing environmentally friendly process of supercritical carbon dioxide (scCO2) impregnation. At selected pressure and temperature, prolongation of operating time increased thymol loading. Pure scCO2 did not affect CA film with average pore diameter of approximately 3 µm, while it enabled change of PCL beads and PLGA flakes into foams with average pore diameter approximately 175 µm and 87 µm, respectively. Additionally to scCO2, thymol acted as a plasticizer increasing pore size of polymers up to three times. Kinetic of thymol release from selected samples was tested using phosphate buffer saline at 37°C and successfully described with Korsmeyer–Peppas, zero-order, first-order, and Higuchi models. The suggested method of PCL, CA, and PLGA supercritical impregnation led to development of porous, solvent free, added-value materials that release thymol in a controlled manner from 5 h to several days.

Preparation and Research of Porous Hydroxyapatite Whiskers/KGM Composite Bone Scaffolds

2013 ◽  
Vol 712-715 ◽  
pp. 415-419
Author(s):  
Ming Hua Huang ◽  
Qing Hua Chen ◽  
Li Lei ◽  
Duan Cheng Wang ◽  
Ting Ting Yan
Keyword(s):  
Compressive Strength ◽  
Degradation Rate ◽  
Pore Diameter ◽  
Sol Gel ◽  
Crosslinking Agent ◽  
Average Pore Diameter ◽  
Average Pore ◽  
Bone Scaffolds ◽  
Composite Bone

Sol-gel method and freeze-drying method were adopted to prepare the porous HAPw/KGM composite bone scaffolds and ammonia was used as a crosslinking agent. The porosity, average pore diameter, compressive strength and degradation rate in vitro were measured according to the related standard. The curves of each factor and lever affecting comprehensive properties were drew through the orthogonal design L9 (34) experiment. SEM and XRD were applied in characterization. The results show that the optimal preparation program of the composite scaffolds is KGM (2g), HAPw (4.5g), ammonia (0.1 ml) and the freeze temperature (-20 ° C); the prepared scaffolds are porous three-dimensional network structures; the porosity of optimal scaffold is more than 90%; the average pore diameter is between 200-300μm; the compressive strength is about 0.8Mpa and the degradation rate is about 50% within 9 weeks.

Dynamics of Fibrovascular Tissue Ingrowth in Hydrogel Foams

1995 ◽  
Vol 4 (3) ◽  
pp. 275-279 ◽  
Author(s):  
M. Conley Wake ◽  
Antonios G. Mikos ◽  
Georgios Sarakinos ◽  
Joseph P. Vacanti ◽  
Robert Langer
Keyword(s):  
Void Fraction ◽  
Pore Diameter ◽  
Average Pore Diameter ◽  
Poly Vinyl Alcohol ◽  
Cell Seeding ◽  
Void Space ◽  
Average Pore ◽  
Tissue Ingrowth ◽  
Fibrovascular Tissue ◽  
Volume Average

We have investigated and quantified the degree of fibrovascular tissue ingrowth in cylindrical poly(vinyl alcohol) (PVA) foams of 12.5 mm diameter, 5 mm thickness, and 71% porosity implanted in the mesentery of rats over a period of 25 days. Fibrovascular tissue penetrated the center of PVA foams 5 days postimplantation yet the void fraction available for cell seeding was 55% and the volume average pore diameter was 190 (±39) μm. By 10 days postimplantation the void fraction had decreased to 32% and the volume average pore diameter was 121 (±20) μm. As time elapsed fibrovascular tissue continued to expand and fill the remaining pore space. At 15 days postimplantation the void space was impractical for cell seeding and continued to decrease through the remainder of the study. Our data suggest that hydrogel foams with a polydispersed pore morphology can be prevascularized with adequate space for cell seeding as the volume of tissue penetrating the foam is limited by the smaller pores in the foam structure; however, available void space for cell seeding decreases with time.

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