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 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.

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.

scholarly journals Strength Analysis of Porous YSZ Ceramics With the Same Porosity and Different Pore Structure

2021 ◽  
Author(s):  
ying lang ◽  
xin dai ◽  
lin zhao ◽  
Hong-Kang wei ◽  
chang-an wang
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Size Structure ◽  
Young's Modulus ◽  
Porous Ceramics ◽  
Strength Analysis ◽  
Large Pore ◽  
Small Pore

Abstract Porous YSZ ceramics with different pore structure were prepared by volume limiting foaming technology. Accurate porosity could achieve by this technology[1], so all samples were adjusted to density of 1g/m3 (porosity of about 82.6%). For the same density, the influence of porosity change on the strength was excluded. The effects of different pore structure on mechanical properties (compressive strength, strength-deformation curve and Young's modulus) were studied. The results showed that for porous ceramics with uniform pores the larger the pore size was, the smaller the Young's modulus and the lower the strength was. In addition, for samples with mix pores (large pore and small pore), when the volume fraction of macropores is large, the strength is the same as that of porous ceramics with uniform small pore size structure; when the volume fraction of small pores is large, the strength is the same as that of porous ceramics with uniform large pore size structure.

Cu2O mesoporous spheres with a high internal diffusion capacity and improved catalytic ability for the aza-Henry reaction driven by visible light

2014 ◽  
Vol 50 (91) ◽  
pp. 14237-14240 ◽  
Author(s):  
Jun Wang ◽  
Jingwen Ma ◽  
Xiaojie Li ◽  
Yang Li ◽  
Guoliang Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Pore Size ◽  
Internal Diffusion ◽  
Henry Reaction ◽  
Diffusion Capacity ◽  
Small Pore Size ◽  
Large Pore ◽  
Small Pore ◽  
Large Pore Size

Mesoporous Cu2O spheres with a large pore size (LP-Cu2O) bring out a better performance towards the photocatalytic aza-Henry reaction than Cu2O spheres with a small pore size (SP-Cu2O).

Spectroscopic imaging of human disease

1996 ◽  
Vol 54 ◽  
pp. 884-885
Author(s):  
D.J. Meyerhoff
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Human Disease ◽  
Morphological Changes ◽  
Magnetic Field Gradient ◽  
Spectroscopic Imaging ◽  
Resonance Spectroscopy ◽  
Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

Sign in / Sign up

Export Citation Format

Share Document