FRACTAL PARAMETERS OF SOIL PORE SURFACE AREA UNDER A DEVELOPING CROP

Fractals ◽  
1996 ◽  
Vol 04 (01) ◽  
pp. 97-104 ◽  
Author(s):  
YA. A. PACHEPSKY ◽  
L. P. KORSUNSKAIA ◽  
M. HAJNOS
Keyword(s):  
Fractal Dimension ◽  
Surface Area ◽  
Plant Development ◽  
Fractal Dimensions ◽  
Carbohydrate Oxidation ◽  
Surface Irregularity ◽  
Pore Surface ◽  
Cutoff Values ◽  
Fractal Parameters ◽  
Pore Surface Area

Fractal parameters of soils has become increasingly important in understanding and quantifying transport and adsorption phenomena in soils. It is not known how soil plant development may affect fractal characteristics of soil pores. We estimated pore surface area fractal parameters from mercury porosimetry data on gray forest soil before and during crop development, in samples both containing and not containing soil carbohydrates known to be important structure-forming agents. Two distinct intervals with different fractal dimensions were found in the range of pore radii from 4 nm to 1 μm. This could be attributed to differences in mineral composition of soil particles of different sizes. The interval of the smallest radii had the highest average fractal dimension close to 3. Smaller surface area fractal dimensions corresponding to low surface irregularity were found in the next interval of radii. The plant development affected neither fractal dimensions nor the cutoff values of soil samples. The carbohydrate oxidation caused a significant increase in the fractal dimension in the interval of larger radii, but did not affect fractal dimension in the interval of small radii. The cutoff values decreased after carbohydrate oxidation.

Geometric pore surface area and fractal dimension of catalyzed electrodes in polymer electrolyte membrane fuel cells

2018 ◽  
Vol 43 (7) ◽  
pp. 3011-3019 ◽  
Author(s):  
Jian Zhao ◽  
Samaneh Shahgaldi ◽  
Adnan Ozden ◽  
Ibrahim E. Alaefour ◽  
Xianguo Li ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Surface Area ◽  
Polymer Electrolyte Membrane ◽  
Pore Surface ◽  
Electrolyte Membrane ◽  
Pore Surface Area

Fractal Parameters of Pore Surface Area as Influenced by Simulated Soil Degradation

1995 ◽  
Vol 59 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Ya. A. Pachepsky ◽  
T. A. Polubesova ◽  
M. Hajnos ◽  
Z. Sokolowska ◽  
G. Józefaciuk
Keyword(s):  
Surface Area ◽  
Soil Degradation ◽  
Pore Surface ◽  
Fractal Parameters ◽  
Pore Surface Area

scholarly journals Nano-Scale Pore Structure and Fractal Dimension of Longmaxi Shale in the Upper Yangtze Region, South China: A Case Study of the Laifeng–Xianfeng Block Using HIM and N2 Adsorption

Minerals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 356 ◽  
Author(s):  
Cheng Huang ◽  
Yiwen Ju ◽  
Hongjian Zhu ◽  
Yu Qi ◽  
Kun Yu ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Surface Area ◽  
South China ◽  
Pore Volume ◽  
Pore Surface ◽  
N2 Adsorption ◽  
Longmaxi Shale ◽  
Pore Surface Area ◽  
Shale Reservoirs

This paper tries to determine the key evaluation parameters of shale reservoirs in the complex tectonic provinces outside the Sichuan Basin in South China, and also to target the sweet spots of shale reservoirs accurately. The pore-structure characteristics of the Lower Silurian Longmaxi shale gas reservoirs in Well LD1 of the Laifeng–Xianfeng Block, Upper Yangtze region, were evaluated. N2 adsorption and helium ion microscope (HIM) were used to investigate the pore features including pore volume, pore surface area, and pore size distribution. The calculated results show good hydrocarbon storage capacity and development potential of the shale samples. Meanwhile, the reservoir space and migration pathways may be affected by the small pore size. As the main carrier of pores in shale, organic matter contributes significantly to the pore volume and surface area. Samples with higher total organic carbon (TOC) content generally have higher porosity. Based on the Frenkel–Halsey–Hill equation (FHH model), two different fractal dimensions, D1 and D2, were observed through the N2 adsorption experiment. By analyzing the data, we found that large pores usually have large values of fractal dimension, owing to their complex pore structure and rough surface. In addition, there exists a good positive correlation between fractal dimension and pore volume as well as pore surface area. The fractal dimension can be taken as a visual indicator that represents the degree of development of the pore structure in shale.

Miicrostructural Evolutiion Duriing Sinteriing

1991 ◽  
Vol 249 ◽  
Author(s):  
R. A. Page ◽  
Y. M. Pan
Keyword(s):  
Surface Area ◽  
Small Angle ◽  
Final Stage ◽  
Intermediate Stage ◽  
Pore Surface ◽  
Pore Density ◽  
Pore Sizes ◽  
Angle Scattering ◽  
Pore Evolution ◽  
Pore Surface Area

ABSTRACTSmall-angle scattering techniques have been used in a number of studies to characterize pore evolution in ceramic compacts. Parameters characterizing the pore distribution, such as total pore surface area, pore size, and pore density, have been measured through both intermediate and final stage sintering. A review of these results indicates that pore sizes were generally found to remain constant during intermediate-stage sintering; supporting a topological decay model of sintering. Pore sizes generally increased and the size distribution broadened during final-stage sintering. The scattering results also suggest the presence of a unique pore surface area versus density curve.

Conservation tillage positively influences soil organic carbon through earthworm excrement physical structure stability in a Chinese Mollisoil

2020 ◽  
Author(s):  
Xuewen Chen ◽  
Aizhen Liang ◽  
Donghui Wu ◽  
Shuxia Jia ◽  
Yan Zhang
Keyword(s):  
Tensile Strength ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Surface Area ◽  
Conservation Tillage ◽  
Water Repellency ◽  
Physical Structure ◽  
Structure Stability ◽  
Pore Surface ◽  
Pore Surface Area

<p>Identifying the relationship between earthworm activity and soil organic carbon is vital for both planning and performing farming operations. Numerous studies have emphasized that earthworms affect soil organic carbon greatly. However, the extent of this effect is still somewhat vague, and very little is known, not to mention the role of earthworm excrement. The objective for this study is to determine the effect of earthworm excrement on soil organic carbon following different tillage practices based on physical structure stability parameters. Both no tillage (NT) and ridge tillage (RT) led to significant total pore surface area, permeability, fluid conductivity, water resistance index and tensile strength increment than moldboard plow (MP) (p<0.05), whereas water repellency significant decrement (p<0.05). Similar to soil organic carbon, NT and RT significantly increase organic carbon in earthworm excrement than MP (p<0.05). A significant positive correlation (p<0.05) was found between organic carbon in earthworm excrement and total pore surface area, water repellency, tensile strength, respectively. This finding demonstrates that conservation tillage increase organic carbon in earthworm excrement through physical structure stability namely aggregation effect of earthworm excrement on soil water movement and gas diffusion, potentially important for the soil organic carbon increment.</p>

Nano/Micro Pore Structure and Fractal Characteristics of Baliancheng Coalfield in Hunchun Basin

2021 ◽  
Vol 21 (1) ◽  
pp. 682-692
Author(s):  
Youzhi Wang ◽  
Cui Mao
Keyword(s):  
Fractal Dimension ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Diameter ◽  
Fractal Dimensions ◽  
Nitrogen Adsorption ◽  
Average Pore ◽  
Coal Reservoir

The pore structure characteristic is an important index to measure and evaluate the storage capacity and fracturing coal reservoir. The coal of Baliancheng coalfield in Hunchun Basin was selected for experiments including low temperature nitrogen adsorption method, Argon Ion milling Scanning Electron Microscopy (Ar-SEM), Nuclear Magnetic Resonance (NMR), X-ray diffraction method, quantitative mineral clay analysis method. The pore structure of coal was quantitatively characterized by means of fractal theory. Meanwhile, the influences of pores fractal dimension were discussed with experiment data. The results show that the organic pores in Baliancheng coalfield are mainly plant tissue pores, interparticle pores and gas pores, and the mineral pores are corrosion pores and clay mineral pores. There are mainly slit pore and wedge-shaped pore in curve I of Low temperature nitrogen adsorption. There are ink pores in curve II with characteristics of a large specific surface area and average pore diameter. The two peaks of NMR T2 spectrum indicate that the adsorption pores are relatively developed and their connectivity is poor. The three peaks show the seepage pores and cracks well developed, which are beneficial to improve the porosity and permeability of coal reservoir. When the pore diameter is 2–100 nm, the fractal dimensions D1 and D2 obtained by nitrogen adsorption experiment. there are positive correlations between water content and specific surface area and surface fractal dimension D1, The fractal dimension D2 was positively and negatively correlated with ash content and average pore diameters respectively. The fractal dimensions DN1 and DN2 were obtained by using the NMR in the range of 0.1 μm˜10 μm. DN1 are positively correlated with specific surface area of adsorption pores. DN2 are positively correlated volume of seepage pores. The fractal dimension DM and dissolution hole fractal dimension Dc were calculated by SEM image method, respectively controlled by clay mineral and feldspar content. There is a remarkable positive correlation between D1 and DN1 and Langmuir volume of coal, so fractal dimension can effectively quantify the adsorption capacity of coal.

scholarly journals Changes in the two-dimensional and perimeter-based fractal dimensions of kaolinite flocs during flocculation: a simple experimental study

2017 ◽  
Vol 77 (4) ◽  
pp. 861-870 ◽  
Author(s):  
Zhongfan Zhu ◽  
Dingzhi Peng ◽  
Jie Dou
Keyword(s):  
Fractal Dimension ◽  
Steady State ◽  
Surface Area ◽  
Dynamic Equilibrium ◽  
Processing System ◽  
Fractal Dimensions ◽  
Flow Shear ◽  
Steady Level ◽  
Axis Length ◽  
Flocculation Time

Abstract In this study, Couette flow experiments were performed to estimate the temporal evolution of the 2D and perimeter-based fractal dimension values of kaolinite flocs during flocculation. The fractal dimensions were calculated based on the projected surface area, perimeter length and length of the longest axis of the flocs as determined by sampling observation and an image-processing system. The 2D fractal dimension, which relates the longest axis length and projected surface area of flocs, was found to decrease with the flocculation time, corresponding to the production of some porous flocs from the flow shear. This fractal dimension finally reached a steady state, which resulted from a dynamic equilibrium among the floc growth, floc breakage and floc restructuring. The perimeter-based fractal dimension, which characterizes the relationship between the projected surface area and the perimeter of flocs, increases with flocculation time because the flow shear increases the collisions among the primary particles, and some irregular flocs are formed. The perimeter-based fractal dimension reaches a steady level because of the balance among floc aggregation, breakage and restructuring. In addition, a stronger turbulent flow shear makes the steady state of fractal dimensions occur early during flocculation.

scholarly journals An Investigation of Fractal Characteristics of Marine Shales in the Southern China from Nitrogen Adsorption Data

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Jian Xiong ◽  
Xiangjun Liu ◽  
Lixi Liang
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Southern China ◽  
Fractal Dimensions ◽  
Nitrogen Adsorption ◽  
Mean Value ◽  
Relative Pressure ◽  
Pore Surface ◽  
Adsorption Sites ◽  
Fractal Characteristics

We mainly focus on the Permian, Lower Cambrian, Lower Silurian, and Upper Ordovician Formation; the fractal dimensions of marine shales in southern China were calculated using the FHH fractal model based on the low-pressure nitrogen adsorption analysis. The results show that the marine shales in southern China have the dual fractal characteristics. The fractal dimensionD1at low relative pressure represents the pore surface fractal characteristics, whereas the fractal dimensionD2at higher relative pressure describes the pore structure fractal characteristics. The fractal dimensionsD1range from 2.0918 to 2.718 with a mean value of 2.4762, and the fractal dimensionsD2range from 2.5842 to 2.9399 with a mean value of 2.8015. There are positive relationships between fractal dimensionD1and specific surface area and total pore volume, whereas the fractal dimensionsD2have negative correlation with average pore size. The larger the value of the fractal dimensionD1is, the rougher the pore surface is, which could provide more adsorption sites, leading to higher adsorption capacity for gas. The larger the value of the fractal dimensionD2is, the more complicated the pore structure is, resulting in the lower flow capacity for gas.

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