Green Preparation, Spheroidal, and Superior Property of Nano-1,3,5,7-Tetranittro-1,3,5,7-Tetrazocane

Herein, a green process for preparing nano-HMX, mechanical demulsification shearing (MDS) technology, was developed. Nano-HMX was successfully fabricated via MDS technology without using any chemical reagents, and the fabrication mechanism was proposed. Based on the “fractal theory,” the optimal shearing time for mechanical emulsification was deduced by calculating the fractal dimension of the particle size distribution. The as-prepared nano-HMX was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). And the impact sensitivities of HMX particles were contrastively investigated. The raw HMX had a lower fractal dimension of 1.9273. The ideal shearing time was 7 h. The resultant nano-HMX possessed a particle size distribution ranging from 203.3 nm to 509.1 nm as compared to raw HMX. Nano-HMX particles were dense spherical, maintaining β-HMX crystal form. In addition, they had much lower impact sensitivity. However, the apparent activation energy as well as thermal decomposition temperature of nano-HMX particles was decreased, attributing to the reduced probability for hotspot generation. Especially when the shearing time was 7 h, the activation energy was markedly decreased.

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Evaluation of particle size distribution of granular blasting materials based on the fractal theory

Advances in Mechanical Engineering ◽

10.1177/1687814019881562 ◽

2019 ◽

Vol 11 (10) ◽

pp. 168781401988156 ◽

Cited By ~ 1

Author(s):

Jiejie Ji ◽

Qiang Yao ◽

Faming Wu ◽

Hongtao Li

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Particle Size Distribution ◽

Size Distribution ◽

Evaluation Method ◽

Fractal Theory ◽

Distribution Model ◽

Uniformity Coefficient ◽

Functional Relationships ◽

Fine Grain

The particle size distribution of granular blasting materials has a vital influence on the filling quality of earth-rockfill dams. The engineering experience-based method used to evaluate the particle size distribution has shortcomings at both the theoretical and practical aspects. This article proposes a new evaluation method based on the fractal theory. Grading sieve tests on granular materials, mass fractal analysis of particle size distribution, and a probability distribution model test of the characteristic parameters are used to revise the functional relationships between the fractal dimension D and the uniformity coefficient/curvature coefficient ( Cu/ Cc) of the grading curve. The feasibility of using D to evaluate the particle size distribution and the optimal fine grain content is then analyzed and determined. According to the results, the geometric shapes of the granular blasting materials have fractal characteristics, and their particle size distribution has a fractal distribution. The ranges of D where the rockfill and transition materials have a good particle size distribution are D = 2.254–2.529 and D = 2.358–2.559, corresponding to optimal fine grain content of 1.953%–11.805% and 10.268%–23.123%, respectively. Fractal dimension has a solid theoretical basis and strong practical applicability as an evaluation index for the particle size distribution of granular blasting materials.

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Analysis of the Correlation Between Strength and Fractal Dimension of Gravelly Soil in Debris-flow Source Areas

The Open Civil Engineering Journal ◽

10.2174/1874149501610010866 ◽

2016 ◽

Vol 10 (1) ◽

pp. 866-876 ◽

Cited By ~ 1

Author(s):

He Na ◽

Li Tao ◽

Zhong Wei ◽

Tom Cosgrove ◽

Zeng Mei

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Internal Friction ◽

Particle Size Distribution ◽

Debris Flow ◽

Size Distribution ◽

Fractal Theory ◽

Soil Samples ◽

Gravelly Soil ◽

Cohesion Force

Particle size distribution of gravelly soil plays a crucial role in debris flow initiation. For better understanding the mechanism of debris flow formation, two crucial mechanical property parameters of the gravelly soil are required to be studied meticulously: hydraulic conductivity and strength. With the aim of measuring the composition of the gravelly soil, 182 soil samples were taken from debris flow prone areas. With the aid of a sieve test, the particle size distribution of the samples can be obtained and analyzed. Then fractal theory was employed to compute the fractal dimension of the soil samples. By analyzing the results of sieve test (particle size distribution curves) and the results of the fractal theory calculations, the relationship between fractal dimension and particle size distribution can be explored. The results illustrate that the particle compositions of the gravelly soil tends to remain uniform as the fractal dimension increases. Moreover, as the coarse particle content increases, the fractal dimension decreases. To better understand the formation mechanism of debris flows, direct shear tests were conducted. Subsequently the experimental results were analyzed. By analysis, the following conclusions can be drawn: the soil strength decreases as the fractal dimension increases, and for soils with lower moisture content and identical dry density, a linear relationship between fractal dimension and cohesion force was identified. Moreover, cohesion force and internal friction force both decrease as the fractal dimension increases, but the internal friction angle decreases slightly while the cohesion force decreases greatly. Therefore we concluded that soil strength decreased mainly due to the reduction in cohesion force.

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Numerical Simulation of Rockfill Materials Based on Fractal Theory

Applied Sciences ◽

10.3390/app12010289 ◽

2021 ◽

Vol 12 (1) ◽

pp. 289

Author(s):

Hongxing Han ◽

Yun Ma ◽

Wei He ◽

Weifang Yang ◽

Xudong Fu

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Particle Size Distribution ◽

Size Distribution ◽

Fine Particles ◽

Mechanical Performance ◽

Fractal Theory ◽

Two Dimensions ◽

Performance Indexes ◽

Fractal Characteristics

With the use of the particle flow code in two dimensions, a fractal model is established with the number of particles of different particle fractions used as the statistics to study the fractal characteristics of particle size distribution. Numerically simulated specimens obtained by four scale methods are subjected to the relative density test and the biaxial compression test to explore the influences of fractal dimension D on the macroscopic and mesomechanical properties of specimens, as well as to study the relationship between fractal dimension D and different mechanical performance indexes. Results show that the particle size distribution of each of the four groups after scale exhibits fractal characteristics, with the fractal dimension D ranging from 1.27 to 2.03. The number of fine particles in the specimen increases with the fractal dimension D, the particle aggregates become more compact, the macroscopic mechanical properties of the specimens are improved, and a linear relationship exists between the fractal dimension D and different mechanical performance indexes. A large fractal dimension D corresponds to a great mesoparticle coordination number.

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Effect of tillage and maize-cowpea intercrop on fractal features of particle and aggregate size distribution on a tropical sandy loam soil in southwest Nigeria

10.36265/njss.2020.300113 ◽

2020 ◽

pp. 102-110

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Organic Carbon ◽

Particle Size Distribution ◽

Size Distribution ◽

Management Practices ◽

Negative Relationship ◽

Fractal Dimensions ◽

Cropping Pattern ◽

The Impact

The effects of tillage and cropping pattern on soil aggregation, fractal dimensions and distribution of organic carbon fractions were studied. Treatments were notillage (NT), conventional tillage (CT), and four cropping patterns viz: sole maize, sole cowpea, maize-cowpea intercrops and control (no crop). Soil samples were analysed for particle size distribution (PSD); aggregation ratio (AR), meanweight diameter (MWD) and aggregated silt+clay (ASC). Mass fractal dimension (Dm) was obtained from PSD; while fragmentation fractal dimension (Df) was obtained from aggregate sizes. Total organic carbon (TOC), free and occluded particulate organic carbon (fPOC and oPOC), were measured. Results showed that structural stability at micro-aggregate scale measured by aggregated silt + clay (ASC) was significantly (p < 0.05) highest for NT (4.07) than CT (1.58). The CT significantly (P ≤ 0.05) reduced the larger aggregate fraction (5.66-2.00 mm). The difference in fractal dimensions was significantly higher with NT than control with CT. Lower difference between Dm and Df with CT represents higher degree of fragmentation of aggregates. Correlation showed significant positive linear relationships between Dm and sand (p < 0.05, r = 0.627) and negative relationship with silt and clay (r = -0.675). Therefore, fractal dimensions derived from aggregates sizes rather than particle size distribution reflected the impact of land management practices on fragmentation of aggregates of most tropical soils.

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Effect of tillage and maize-cowpea intercrop on fractal features of particle and aggregate size distribution on a tropical sandy loam soil in southwest Nigeria

10.36265/njss.2020.290213 ◽

2019 ◽

pp. 102-109

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Organic Carbon ◽

Particle Size Distribution ◽

Size Distribution ◽

Management Practices ◽

Sandy Loam ◽

Fractal Dimensions ◽

Cropping Pattern ◽

The Impact

The effects of tillage and cropping pattern on soil aggregation, fractal dimensions and distribution of organic carbon fractions were studied. Treatments were no- tillage (NT), conventional tillage (CT), and four cropping patterns viz: sole maize, sole cowpea, maize-cowpea intercrops and control (no crop). Soil samples were analysed for particle size distribution (PSD); aggregation ratio (AR), mean- weight diameter (MWD) and aggregated silt+clay (ASC). Mass fractal dimension (Dm) was obtained from PSD; while fragmentation fractal dimension (Df) was obtained from aggregate sizes. Total organic carbon (TOC), free and occluded particulate organic carbon (fPOC and oPOC), were measured. Results showed that structural stability at micro-aggregate scale measured by aggregated silt + clay (ASC) was significantly (p < 0.05) highest for NT (4.07) than CT (1.58). The CT significantly (P ≤ 0.05) reduced the larger aggregate fraction (5.66-2.00 mm). The difference in fractal dimensions was significantly higher with NT than control with CT. Lower difference between Dm and Df with CT represents high- er degree of fragmentation of aggregates. Correlation showed significant positive linear relationships between Dm and sand (p < 0.05, r = 0.627) and negative rela- tionship with silt and clay (r = -0.675). Therefore, fractal dimensions derived from aggregates sizes rather than particle size distribution reflected the impact of land management practices on fragmentation of aggregates of most tropical soils.

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Study on the impact of particle size distribution on turbidity in water

Desalination and Water Treatment ◽

10.1080/19443994.2012.664675 ◽

2012 ◽

Vol 41 (1-3) ◽

pp. 26-34 ◽

Cited By ~ 14

Author(s):

Weipeng He ◽

Jun Nan

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

The Impact

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Slope scale spatial variability of fractal dimension of soil particle size distribution at multiple depths

Soil Science Society of America Journal ◽

10.1002/saj2.20178 ◽

2020 ◽

Author(s):

Xinyu Zou ◽

Zhuodong Zhang ◽

Mengyao Wu ◽

Yuanqiang Wan

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Particle Size Distribution ◽

Spatial Variability ◽

Size Distribution ◽

Soil Particle ◽

Soil Particle Size ◽

Soil Particle Size Distribution

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Fractal dimension of particle-size distribution and their relationships with alkalinity properties of soils in the western Songnen Plain, China

Scientific Reports ◽

10.1038/s41598-020-77676-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Yufeng Bai ◽

Yan Qin ◽

Xinrui Lu ◽

Jitao Zhang ◽

Guoshuang Chen ◽

...

Keyword(s):

Particle Size ◽

Fractal Dimension ◽

Particle Size Distribution ◽

Size Distribution ◽

Linear Regression Analysis ◽

Salt Content ◽

Clay Content ◽

Fine Sand ◽

Alkaline Soil ◽

Songnen Plain

AbstractThe purpose of this study was to identify the fractal dimension and their relationships with alkalinity properties of soils, and to evaluate the potential of fractal dimension as an indicator of alkalinity properties of soil. Six soils with an increasing salinity (electrical conductivity was 0.09, 0.18, 0.62, 0.78, 1.57 and 1.99 dS m−1, respectively) were selected from the western part of the Songnen Plain (China). Salt content, exchangeable sodium percentage, sodium adsorption ratio and other properties of the soils were determined and the soil particle-size distribution (0–2000 μm) was measured using a laser diffraction particle size analyser. Our results show that the overall fractal dimension of the selected soils ranged from 2.35 to 2.60. A linear regression analysis showed a significant negative correlation between fractal dimension and the amount of coarse sand and fine sand (r = − 0.5452, P < 0.05 and r = − 0.8641, P < 0.01, respectively), and a significant positive correlation with silt and clay (r = 0.9726, P < 0.01 and r = 0.9526, P < 0.01, respectively). Thus, soils with higher silt and clay content have higher fractal dimension values. Strong linear relationships between fractal dimension and salt content (P < 0.05), in particular a very significant positive relationship with HCO3− (P < 0.01), also exist. It is therefore possible to conclude that a soil’s fractal dimension could serve as a potential indicator of soil alkalization and the variability in alkaline soil texture.

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