scholarly journals Experimental Study on Nonlinear Seepage Characteristics and Particle Size Gradation Effect of Fractured Sandstones

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Xuyang Shi ◽  
Wei Zhou ◽  
Qingxiang Cai ◽  
Xiang Lu
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Fractured Rock ◽  
Average Pore Size ◽  
Fractured Rock Mass ◽  
Average Pore ◽  
Seepage Pressure ◽  
Seepage Characteristics ◽  
Fractured Sandstone ◽  
Particle Size Gradation

Seepage mutation of fractured rock mass is one of the main inducements of dump slide and other disasters. Pore structure is a significant factor affecting the seepage characteristics of fractured rock mass, while particle size gradation has an important effect on the distribution of pore structure. Through the self-developed experimental system, the nonlinear seepage test on the fractured sandstones of the coalseam roof was conducted to investigate the influence of seepage pressure, porosity, and fractal dimension. Besides, the nonlinear seepage model was established by Barree–Conway theory. The results showed that, during the seepage process of fractured sandstone, there were significant nonlinear characteristics, which increased with the increase of the seepage pressure. With the increasing porosity, there was greater average pore size of fractured sandstone, stronger permeability, and weaker nonlinear seepage. The seepage characteristics approximated to that of Darcy model. However, with increasing grading fractal dimension, there were smaller average pore size of fractured sandstone, weaker permeability, and stronger nonlinear seepage. The seepage characteristics approximated to that of Forchheimer model.

Effect of Carbon Particle Size and Content on the Mechanical and Thermal Properties of Recycled SLS Glass Composite

2016 ◽  
Vol 694 ◽  
pp. 34-38
Author(s):  
Zaleha Mustafa ◽  
Zurina Shamsudin ◽  
Radzali Othman ◽  
Nur Fashiha Sapari ◽  
Jariah Mohd Juoi ◽  
...  
Keyword(s):  
Particle Size ◽  
Thermal Properties ◽  
Average Pore Size ◽  
Carbon Particle ◽  
Physical And Mechanical Properties ◽  
Waste Glass ◽  
Mechanical And Thermal Properties ◽  
Glass Composite ◽  
Average Pore ◽  
Glass Composites

Glass-composite materials were prepared from the soda lime silicate (SLS) waste glass; ball clay and charcoal powder were fired to temperature of 850 °C as an effort for recycling waste glass. Various carbon contents, i.e., 1, 5, 10, 20 and 30 wt.% C were used to evaluate the effect of carbon contents on the hardness and thermal properties of glass composites. In addition, five different particles size (d0.5) of 1, 5, 20, 40 and 75 μm were used to observe the influence of particle size on the physical and mechanical properties of the glass composites. Phase analysis studies revealed the presence of quartz (ICDD: 00001-0649, 2θ = 25.6° and 35.6°), cristobalite (ICDD 00004-0379, 2θ = 22.0° and 38.4°) and wollastonite (ICDD 00002-0689, 2θ = 30.1° and 26.9°). The results showed that the optimised properties is at 1 wt.% of carbon content containing average pore size of 10 μm, with lowest porosity percentage of 1.76 %, highest Vickers microhardness of 4.6 GPa and minimum CTE. The percentage of porosity and hardness value also increased with reduction in carbon particle size.

PORE STRUCTURE CHARACTERIZATION FOR A CONTINENTAL LACUSTRINE SHALE PARASEQUENCE BASED ON FRACTAL THEORY

Fractals ◽  
2019 ◽  
Vol 27 (01) ◽  
pp. 1940006 ◽  
Author(s):  
LEI ZHANG ◽  
XUEJUAN ZHANG ◽  
HAO CHAI ◽  
YAOCAI LI ◽  
YONGJIE ZHOU
Keyword(s):  
Fractal Dimension ◽  
Pore Structure ◽  
Pore Size ◽  
Clay Mineral ◽  
Mineral Content ◽  
Fractal Theory ◽  
Average Pore Size ◽  
Structure Characterization ◽  
Imaging Method ◽  
Average Pore

Fractal dimension is an important parameter in the evaluation of tight reservoirs. For an outcrop section of the Nenjiang formation in the Songliao Basin, China, the pore structure and pore fractal characteristics of shale parasequences were investigated using fractal theory. In addition, factors causing pore structure changes were analyzed using the results of low-temperature nitrogen adsorption and scanning electron microscope (SEM) experiments. Conducive to gas migration and secondary pores development such as dissolution, results showed that nanoscale pores dominated by fracture-like morphology and consequent good internal connectivity were observed in each pore size section within the target layer. Each parasequence is characterized by a sequential upward decrease of average pore size and an upward increase of total pore volume, with an increasing number of pores from 2[Formula: see text]nm to 50[Formula: see text]nm. Pores are isolated from each other, with poor connectivity and relatively complex composition of brittle minerals and clay minerals. Main components of the brittle minerals, quartz and feldspar, occur in 20–50% and higher clay mineral content ranging from 50% to 70%. In the parasequence cycle, clay mineral gradually decreases while the brittle mineral content increases. Fractal dimension is negatively correlated with clay mineral content and positively correlated with brittle mineral (quartz and feldspar) content. The fractal dimension calculated by the imaging method and the FHH method shows an upward increasing tendency in each of the parasequence cycles. This is as a result of different phenomena, varied sediment hydrodynamic forces leading to particle size differences and increased brittle minerals resulting in microcracks, therefore, the fractal dimension of the large pores (imaging method) increases upward in the parasequence. Simultaneously, with increased content and accompanied dissolution of brittle minerals causing an increase of small pores from base to top of the parasequence, the fractal dimension of the small pores (FHH method) grows.

scholarly journals Comprehensive Fractal Model and Pore Structural Features of Medium- and Low-Rank Coal from the Zhunnan Coalfield of Xinjiang, China

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 7
Author(s):  
Haifei Lin ◽  
Yang Bai ◽  
Jingting Bu ◽  
Shugang Li ◽  
Min Yan ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Thermodynamic Model ◽  
Vitrinite Reflectance ◽  
Average Pore Size ◽  
Full Range ◽  
Complex Structure ◽  
Structural Features ◽  
Low Rank ◽  
Low Rank Coal ◽  
Average Pore

Medium and low-rank coal from the Zhunnan coalfield of Xinjiang in China was investigated for quantitatively characterizing its range of aperture structure. The pore parameters were determined by nitrogen adsorption at low temperature and mercury injection at high pressure, and the full aperture was determined. The FHH model, Menger model, Sierpinski model, and a thermodynamic model were used to calculate the comprehensive fractal dimension of the coal samples over the full range of aperture. The fractal characteristics of the pores of medium- and low-rank coal were quantitatively analyzed, which provided a reference for the overall characterization of pore structure heterogeneity in this coalfield. The results show that the FHH model and thermodynamic model more accurately calculate the fractal dimensions of less and greater than the joint pore position, respectively. The comprehensive fractal dimension of the low-rank coal pore is 2.8005–2.8811 and that of medium rank coal is 2.5710–2.6147. When compared with the medium-rank coal, pores of the low-rank coal are more developed and they exhibit a more complex structure with stronger heterogeneity. The comprehensive fractal dimension of the pores is a negative correlation with average pore size, vitrinite content, and maximum vitrinite reflectance, and positive correlation with pore volume, pore specific surface area, inertinite content, and exinite content.

scholarly journals A Fractal Model for Characterizing Hydraulic Properties of Fractured Rock Mass under Mining Influence

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xiaoli Liu ◽  
Tao Liang ◽  
Sijing Wang ◽  
Kumar Nawnit
Keyword(s):  
Fractal Dimension ◽  
Rock Mass ◽  
Permeability Coefficient ◽  
Fractured Rock ◽  
Length Distribution ◽  
Fracture Network ◽  
Fractal Model ◽  
Physical Model Test ◽  
Fractured Rock Mass ◽  
Fractal Characteristics

In this paper, two basic assumptions are introduced: (1) The number and length distribution of fractures in fractured rock mass are in accordance with the fractal law. (2) Fluid seepage in the fractures satisfies the cubic law. Based on these two assumptions, the fractal model of parallel seepage and radial seepage in fractured rock mass is established, and the seepage tensor of fracture network which reflects the geometric characteristics and fractal characteristics of fracture network under two kinds of seepage is derived. The influence of fracture geometry and fractal characteristics on permeability is analyzed, and the validity and accuracy of the model are verified by comparing the calculated results of the theoretical model and physical model test. The results show that the permeability coefficient K of fracture network is a function of the geometric (maximum crack length Lmax, fractured horizontal projection length L0, diameter calculation section porosity Φ, fracture strike α, and fracture angle θ) and fractal characteristics (fracture network fractal dimension Df and seepage flow fractal dimension DT). With the increase of fractal dimension Df, the permeability coefficient increases. With the increase of DT, the permeability coefficient decreases rapidly. And the larger the Df (Df>1.5), the greater the change of permeability coefficient K with DT.

Preparation SiC Ceramic Composite Filtration Membrane Materials by Dry Pressing and Synchronous Sintering Method

2013 ◽  
Vol 690-693 ◽  
pp. 409-414
Author(s):  
Kui Fan Su ◽  
Li Ming Wang ◽  
Xiang Yun Deng ◽  
Jian Bao Li ◽  
Chun Peng Wang ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Particle Size ◽  
Pressure Drop ◽  
Pore Size ◽  
Ceramic Composite ◽  
Average Pore Size ◽  
Molding Pressure ◽  
Average Pore ◽  
Silicon Carbide Particle ◽  
Filtration Membrane

Silicon carbide ceramic composite filter membrane materials were prepared by dry pressure molding and synchronous sintering process at sintering temperature of 1300oC for 3h. and research the influence of on the molding pressure structure of SiC filtration membrane,effect of particle size on porosity, average pore size and filter pressure drop of filtration membrane, SEM was performed to examine the morphology, The porosity ,average pore size and filter pressure drop of filtration membrane were tested by Archimedes method ,bubble point method and filter pressure drop instrument. It is demonstrated that while the molding pressure (F) varied from 1MPa to 10MPa, the filter membrane material achieved preferable morphology and best performance when F equals to 5MPa. Under this modeling pressure, while silicon carbide particle size increased from 1 to 23μm, the pore ratio decreased from 48.0% to 36.2% and the average pore size increased from 0.35μm to 9.4μm, while the air gas velocity changed from 0 to 0.112m/s, the filter pressure drop increased, when the velocity is stable, the filter pressure drop reduced as the silicon carbide particle size.

scholarly journals Addition of buttermilk powder to yogurt: effects on particle size, microstructure and texture

2021 ◽  
Vol 10 (11) ◽  
pp. e154101119404
Author(s):  
Elisângela Ramieres Gomes ◽  
Mariana Braga de Oliveira ◽  
Isis Rodrigues Toledo Renhe ◽  
Rodrigo Stephani ◽  
Antônio Fernandes de Carvalho ◽  
...  
Keyword(s):  
Particle Size ◽  
Profile Analysis ◽  
Average Pore Size ◽  
Control Sample ◽  
Average Pore ◽  
Fat Replacer ◽  
Ph Variation ◽  
Texture Profile ◽  
Buttermilk Powder ◽  
Network Microstructure

The addition of buttermilk powder as partial fat replacer in yogurt formulations with constant dry matter was investigated. Three formulations of yogurt were produced containing 0% (T1), 1.36% w·w-1 (T2) and 3.34% w·w-1 (T3) of buttermilk powder in the final product. Particle size and pH variation were monitored during fermentation; scanning electron microscopy and texture profile analysis were performed in the final product. The control sample showed larger particle size on the day after production and at the end of fermentation, as well as a more compact network microstructure with a smaller average pore size. Compared to the prototypes with added buttermilk the control sample showed greater higher firmness. Buttermilk powder could act as fat replacer for yogurt but favors the formation of a less compacted network microstructure, with large pores, less springiness after 21 days, and less hardness in the two evaluated times (21 and 42 days).

scholarly journals Seepage Evolution Model of the Fractured Rock Mass under High Seepage Pressure in Dam Foundation

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Erfeng Zhao ◽  
Yufeng Jiang
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Constitutive Models ◽  
Storage Period ◽  
Creep Damage ◽  
Fractured Rock Mass ◽  
Dam Foundation ◽  
Compression Creep ◽  
Seepage Characteristics

The seepage of the fractured rock mass in dam foundations involves complex fluid-structure coupling behavior, due to practical hydrogeological conditions. In this work, the seepage characteristics of the fractured rock mass and their correlations with the structural permeable mediums are experimentally explored to reveal the cracking effect on the hydromechanical properties firstly. Subsequently, the tangential and the compression creep damage constitutive models are, respectively, established by introducing a nonlinear viscoplastic body to improve the Nishihara model. Afterwards, an innovative evolution equation of the permeability coefficient considering the creep damage is proposed. It can indicate the time effect of the porosity, the permeability, and damage variables of the fractured rock mass under the long-term infiltration action of the hydraulic pressures. Ultimately, the proposed methods are applied to the seepage simulation on the dam foundation of the Longyangxia hydropower station and the significantly increased leakage is in good agreement with the measured values during the storage period. It was further confirmed that the crack expansion and penetration in the rock masses can be constantly intensified by the seepage pressures. The research results can provide a reference for engineering repair and supervision through controlling the permeability performance for long-term operations.

Experimental Study of the Effect of Fly Ash Particle Size on its Mercury Adsorption Capability in the Flue Gas

2011 ◽  
Vol 356-360 ◽  
pp. 1664-1667 ◽  
Author(s):  
Jiang Wu ◽  
Peng Wang ◽  
Lu Lu He ◽  
Wei Guo Pan ◽  
Jian Xing Ren ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Flue Gas ◽  
Average Pore Size ◽  
Mercury Content ◽  
Sem Analysis ◽  
Unburned Carbon ◽  
Adsorption Efficiency ◽  
Average Pore ◽  
Series Of Experiments

In this paper, fly ash samples were collected from a coal-fired power in Shanghai. A series of experiments, including unburned carbon testing, mercury content measurement, SEM analysis, specific surface area, average pore size and pore volume test, were conducted, and the adsorption ability of the fly ash on the flue gas mercury was also experimentally studied. It has shown that fly ash with particle size bigger than 100µm is with the highest adsorption efficiency, 67.83%, and that fly ash with particle size smaller than 25µm is with the smallest adsorption efficiency, 13.67%. The relative mechanism was analyzed.

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