scholarly journals Monitoring of the Variation in Pore Sizes of Woven Geotextiles with Uniaxial Tensile Strain

2021 ◽  
Vol 12 (1) ◽  
pp. 374
Author(s):  
Wenfang Zhao ◽  
Xiaowu Tang ◽  
Keyi Li ◽  
Jiaxin Liang ◽  
Weikang Lin ◽  
...  
Keyword(s):  
Pore Size ◽  
Tensile Strain ◽  
Pore Diameter ◽  
Filter Design ◽  
Uniaxial Tensile ◽  
Distribution Diagram ◽  
Pore Sizes ◽  
Large Pore ◽  
Small Pore ◽  
Pore Opening

Characteristic pore-opening size O95 or O90 has been widely used in the filter design of woven geotextiles. These manufactured products have different pore size proportions of large pore diameters, medium pore diameters, and small pore diameters, respectively. Therefore, uncertainties still exist regarding the prediction of geotextile pore diameter variations under the uniaxial tensile strain. This paper investigates the variations in five characteristic pore-opening sizes O95, O80, O50, O30, and O10, with uniaxial tensile strain by using the image analysis method. The large pore diameters, medium pore diameters, and small pore diameters show different variation behaviors as the uniaxial tensile strain increases. Fifteen specific pores are selected and then their pore diameter variations are monitored under each tensile strain of 1%. The colorful pore size distribution diagram is a visual way to identify the variation of pores arranged in the tension direction (warp direction) and the direction perpendicular to tensile loads (weft direction). The various pore diameters are proved to agree well with the bell-shaped Gaussian distribution. The results exhibit an accurate prediction of the variation in large pore sizes, medium pore sizes, and small pore sizes, respectively, for all tested woven geotextiles with uniaxial tensile strain.

Tailoring the Pore Size of Hypercrosslinked Polymer Foams

1996 ◽  
Vol 431 ◽  
Author(s):  
W. P. Steckle ◽  
M. A. Mitchell ◽  
P. G. Apen
Keyword(s):  
Pore Size ◽  
Polyaromatic Hydrocarbons ◽  
Crosslinking Agent ◽  
Nitrogen Adsorption ◽  
Total Surface Area ◽  
Pore Sizes ◽  
Surface Areas ◽  
Small Pore ◽  
High Resolution Tem ◽  
Cure Time

AbstractOrganic analogues to inorganic zeolites would be a significant step forward in engineered porous materials and would provide advantages in range, selectivity, tailorability and processing. Rigid molecular foams or “organic zeolites” would not be crystalline materials and could be tailored over a broader range of pore sizes and volumes. A novel process for preparing hypercrosslinked polymeric foams has been developed via a Friedel-Crafts polycondensation reaction. A series of rigid hypercrosslinked foams have been prepared using simple rigid polyaromatic hydrocarbons including benzene, biphenyl, m-terphenyl, diphenylmethane, and polystyrene, with p-dichloroxylene (DCX) or divinylbenzene (DVB) as the crosslinking agent. Transparent gels are formed suggesting a very small pore size. After drying the foams are robust and rigid. Densities of the resulting foams can range from 0.15g/cc to 0.75g/cc. Nitrogen adsorption studies have shown that by judiciously selecting monomers and crosslinking agent along with the level of crosslinking and the cure time of the resulting gel, the pore size, pore size distribution, and the total surface area of the foam can be tailored. Surface areas range from 160 to 1,200 m2/g with pore sizes ranging from 6Å to 2,000Å. Further evidence of the uniformity of the foams and their pore sizes has been confirmed by high resolution TEM.

scholarly journals SBA-15 with Crystalline Walls Produced via Thermal Treatment with the Alkali and Alkali Earth Metal Ions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5270
Author(s):  
Sung Soo Park ◽  
Sang-Wook Chu ◽  
Liyi Shi ◽  
Shuai Yuan ◽  
Chang-Sik Ha
Keyword(s):  
Metal Ions ◽  
Pore Size ◽  
Metal Ion ◽  
Pore Diameter ◽  
Earth Metal ◽  
Silica Matrix ◽  
Alkali Earth Metal ◽  
Alkali Earth ◽  
Large Pore ◽  
Large Pore Size

Crystalline walled SBA-15 with large pore size were prepared using alkali and alkali earth metal ions (Na+, Li+, K+ and Ca2+). For this work, the ratios of alkali metal ions (Si/metal ion) ranged from 2.1 to 80, while the temperatures tested ranged from 500 to 700 °C. The SBA-15 prepared with Si/Na+ ratios ranging from 2.1 to 40 at 700 °C exhibited both cristobalite and quartz SiO2 structures in pore walls. When the Na+ amount increased (i.e., Si/Na increased from 80 to 40), the pore size was increased remarkably but the surface area and pore volume of the metal ion-based SBA-15 were decreased. When the SBA-15 prepared with Li+, K+ and Ca2+ ions (Si/metal ion = 40) was thermally treated at 700 °C, the crystalline SiO2 of quartz structure with large pore diameter (i.e., 802.5 Å) was observed for Ca+2 ion-based SBA-15, while no crystalline SiO2 structures were observed in pore walls for both the K+ and Li+ ions treated SBA-15. The crystalline SiO2 structures may be formed by the rearrangement of silica matrix when alkali or alkali earth metal ions are inserted into silica matrix at elevated temperature.

scholarly journals Changing Characteristics of Sandstone Pore Size under Cyclic Loading

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jiaguang Kan ◽  
Guichen Li ◽  
Nong Zhang ◽  
Peng Wang ◽  
Changliang Han ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Cyclic Loading ◽  
Pore Size ◽  
Testing Machine ◽  
Physical And Mechanical Properties ◽  
Spectral Peak ◽  
Resonance Spectroscopy ◽  
Large Pore ◽  
Small Pore ◽  
Increasing Load

The size and distribution of pores in rocks are closely related to their physical and mechanical properties. It is important to study the structure and distribution of pore size inside the rock to assess the risk of damage to a given rock volume. These characteristics were studied under different pressures, pore diameters, and pore throat size distribution laws using a UTM5540 electronic universal testing machine, magnetic resonance imaging scanning, and low field nuclear magnetic resonance spectroscopy with cyclic loading on yellow sandstone. We found the following. (1) Under 0–10 MPa load, the peaks of the sandstone T 2 spectrum move left as load increases, and the porosity of the sandstone decreases. The peak area of the middle relaxation spectrum increases as pressure increases from 10 to 20 MPa, and a peak for the long relaxation time spectrum appears. (2) Under 0–10 MPa load, the spectral peak associated with a large pore moves left and decreases in area as pressure increases. Under 10–20 MPa load, the large-pore spectral peak moves right and increases in area as pressure increases. (3) Under the applied 0–10 MPa load, the porosity of water-saturated sandstone gradually decreases, and the sandstone NMR images darken with increasing load. The porosity of saturated sandstone gradually increases under 10–20 MPa pressure, and its NMR image brightens. (4) The number of small pore throats increases with increasing load, but the number of large- and medium-sized pore throats decreases. From 0 to 15 MPa, crack (>1 micron) abundance decreases, and fractures are generated by compaction under a 20 MPa load. The pore interconnectivity is enhanced, as are the number and size of pores in the sandstone. With continuing increasing pressure, the numbers of pores and penetration of cracks increase, which damages the sandstone.

scholarly journals Prediction of Pore Size Characteristics of Needle-Punched Nonwoven Geotextiles Subjected to Uniaxial Tensile Strains

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Lin Tang ◽  
Qiang Tang ◽  
Aolai Zhong ◽  
Hanjie Li
Keyword(s):  
Pore Size ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Uniaxial Tensile ◽  
Modified Model ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Out Of Plane ◽  
Tensile Strains ◽  
The Difference

A modified theoretical model has been proposed to predict the pore size characteristics of nonwoven geotextiles under certain uniaxial tensile strains, considering the difference between the out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles. The pore size distributions (PSDs) and O95 subjected to different levels of uniaxial tensile strains in two needle-punched nonwoven geotextiles have been investigated by the dry sieving test. The variation of the fibre orientation with tensile strains and the corresponding effect on pore sizes has been evaluated by image analysis. The out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles have been examined. A comparison has been made between the predictions of the original and the modified models. It is shown that the modified model can more accurately predict the decreasing rate of the PSDs, O95, and O98 than the original one. The corrected theoretical O95 and O98 under certain strains can provide a reference for the filtration design under engineering strains. The fibres reorientating to the loading direction result in the increase of the directional parameter with increasing tensile strains, which leads to the decrease of pore sizes. The theoretical PSDs are sensitive to the variation of directional parameter.

A distributed two-pore model: theoretical implications and practical application to the glomerular sieving of Ficoll

2014 ◽  
Vol 306 (8) ◽  
pp. F844-F854 ◽  
Author(s):  
Carl M. Öberg ◽  
Bengt Rippe
Keyword(s):  
Pore Radius ◽  
Diffusion Length ◽  
Wide Distribution ◽  
Analytic Solutions ◽  
Length Ratio ◽  
Pore Sizes ◽  
Filtration Barrier ◽  
Large Pore ◽  
Small Pore ◽  
Pore Area

In the present study, an extended two-pore theory is presented where the porous pathways are continuously distributed according to small- and large-pore mean radii and SDs. Experimental glomerular sieving data for Ficoll were analyzed using the model. In addition, several theoretical findings are presented along with analytic solutions to many of the equations used in distributed pore modeling. The results of the data analysis revealed a small-pore population in the glomerular capillary wall with a mean radius of 36.6 Å having a wide arithmetic SD of ∼5 Å and a large-pore radius of 98.6 Å with an even wider SD of ∼44 Å. The small-pore radius obtained in the analysis was close to that of human serum albumin (35.5 Å). By reanalyzing the data and setting the distribution spread of the model constant, we discovered that a narrow distribution is compensated by an increased mean pore radius and a decreased pore area-to-diffusion length ratio. The wide distribution of pore sizes obtained in the present analysis, even when considering electrostatic hindrance due to the negatively charged barrier, is inconsistent with the high selectivity to proteins typically characterizing the glomerular filtration barrier. We therefore hypothesize that a large portion of the variance in the distribution of pore sizes obtained is due to the molecular “flexibility” of Ficoll, implying that the true variance of the pore system is lower than that obtained using flexible probes. This would also, in part, explain the commonly noted discrepancy between the pore area-to-diffusion length ratio and the filtration coefficient.

Preparation of Carbon Nanotubes by Using Mesoporous Silica

2001 ◽  
Vol 675 ◽  
Author(s):  
Shinji Kawasaki ◽  
Shingo Komiyama ◽  
Shigekazu Ohmori ◽  
Akifumi Yao ◽  
Fujio Okino ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mesoporous Silica ◽  
Pore Size ◽  
Present Method ◽  
Pore Sizes ◽  
Small Pore Size ◽  
Small Pore ◽  
Uniform Diameter ◽  
20 Nm

ABSTRACTCarbon nanotubes were synthesized using several mesoporous silica templates with different pore sizes in order to investigate the possibility of controlling the diameter of carbon nanotubes by changing the pore size of the mesoporous silica. TEM observation confirmed that carbon nanotubes with uniform diameter can be obtained by the present method. However, it was found that it is difficult to prepare carbon nanotubes having diameter smaller than ∼20 nm by the present method even if the template with small pore size is used.

scholarly journals Statistical Analysis of Synthesis Parameters to Fabricate PVDF/PVP/TiO2 Membranes via Phase-Inversion with Enhanced Filtration Performance and Photocatalytic Properties

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 113
Author(s):  
Erika Nascimben Santos ◽  
Ákos Fazekas ◽  
Cecilia Hodúr ◽  
Zsuzsanna László ◽  
Sándor Beszédes ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Statistical Analysis ◽  
Pore Size ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Pure Water ◽  
Water Flux ◽  
Pore Sizes ◽  
Small Pore ◽  
Pure Water Flux

Non-solvent induced phase-inversion is one of the most used methods to fabricate membranes. However, there are only a few studies supported by statistical analysis on how the different fabrication conditions affect the formation and performance of membranes. In this paper, a central composite design was employed to analyze how different fabrication conditions affect the pure water flux, pore size, and photocatalytic activity of polyvinylidene fluoride (PVDF) membranes. Polyvinylpyrrolidone (PVP) was used to form pores, and titanium dioxide (TiO2) to ensure the photocatalytic activity of the membranes. The studied bath temperatures (15 to 25 °C) and evaporation times (0 to 60 s) did not significantly affect the pore size and pure water flux of the membranes. The concentration of PVDF (12.5 to 17.5%) affected the viscosity, formation capability, and pore sizes. PVDF at high concentrations resulted in membranes with small pore sizes. PVP affected the pore size and should be used to a limited extent to avoid possible hole formation. TiO2 contents were responsible for the decolorization of a methyl orange solution (10−5 M) up to 90% over the period studied (30 h). A higher content of TiO2 did not increase the decolorization rate. Acidic conditions increased the photocatalytic activity of the TiO2-membranes.

scholarly journals ROLE OF REDUCING CELL LEAKAGE IN CELL CULTURE USING LARGE PORE SIZE PERMEABLE MEMBRANE

2017 ◽  
Vol 6 (1) ◽  
pp. 16
Author(s):  
Nur Kaliwantoro ◽  
Marsetyawan HNE Soesatyo ◽  
Indarto Indarto ◽  
Mohammad Juffrie ◽  
Rini Dharmastiti ◽  
...  
Keyword(s):  
Cell Culture ◽  
Vero Cell ◽  
Pore Size ◽  
Flow Chamber ◽  
Permeable Membrane ◽  
Large Pore ◽  
Small Pore ◽  
Large Pore Size ◽  
Cell Leakage

Permeable membranes are widely used in many in vitro studies using cell culture. Some cell leakage are often occurs when using permeable membrane with large pore size. Unfortunately the use of permeable membrane with smaller pore size in permeability studies faces some difficulties due to its small pore size and pore density. Recent study provides the protocol in using permeable membrane with large pore size with smaller cell leakage. Vero cell line (CCL-81, ATCC) was used and culture on polyester permeable membrane with 3 µm pore size. Visualization using inverted microscope was used to analized the cell leakage on the permeable membrane. Parallel plate flow chamber was used to analized the permeability performance of the Vero cell cultured on the permeable membrane. The result showed that the current technique is significant in reducing cell leakage of the cell cultured on large pore size of permeable membrane. The same results were found in using polyester and polycarbonate permeable membrane.

scholarly journals Osteochondral Tissue Regeneration Using a Tyramine-Modified Bilayered PLGA Scaffold Combined with Articular Chondrocytes in a Porcine Model

2019 ◽  
Vol 20 (2) ◽  
pp. 326 ◽  
Author(s):  
Tzu-Hsiang Lin ◽  
Hsueh-Chun Wang ◽  
Wen-Hui Cheng ◽  
Horng-Chaung Hsu ◽  
Ming-Long Yeh
Keyword(s):  
Articular Cartilage ◽  
Pore Size ◽  
Collagen Type ◽  
Articular Chondrocytes ◽  
Plga Scaffold ◽  
Small Pore Size ◽  
Large Pore ◽  
Small Pore ◽  
Osteochondral Tissue ◽  
Large Pore Size

Repairing damaged articular cartilage is challenging due to the limited regenerative capacity of hyaline cartilage. In this study, we fabricated a bilayered poly (lactic-co-glycolic acid) (PLGA) scaffold with small (200–300 μm) and large (200–500 μm) pores by salt leaching to stimulate chondrocyte differentiation, cartilage formation, and endochondral ossification. The scaffold surface was treated with tyramine to promote scaffold integration into native tissue. Porcine chondrocytes retained a round shape during differentiation when grown on the small pore size scaffold, and had a fibroblast-like morphology during transdifferentiation in the large pore size scaffold after five days of culture. Tyramine-treated scaffolds with mixed pore sizes seeded with chondrocytes were pressed into three-mm porcine osteochondral defects; tyramine treatment enhanced the adhesion of the small pore size scaffold to osteochondral tissue and increased glycosaminoglycan and collagen type II (Col II) contents, while reducing collagen type X (Col X) production in the cartilage layer. Col X content was higher for scaffolds with a large pore size, which was accompanied by the enhanced generation of subchondral bone. Thus, chondrocytes seeded in tyramine-treated bilayered scaffolds with small and large pores in the upper and lower parts, respectively, can promote osteochondral regeneration and integration for articular cartilage repair.

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