scholarly journals Prediction Model of Minimum Void Ratio for Various Sizes/Shapes of Sandy Binary Mixture

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Chaojie Shen ◽  
Zhaoyang Xu ◽  
Jie Yin ◽  
Jinfeng Wu
Keyword(s):  
Particle Size ◽  
Binary Mixture ◽  
Particle Shape ◽  
Void Ratio ◽  
Soil Mechanics ◽  
Influence Factors ◽  
Natural Sand ◽  
Undetermined Coefficient ◽  
Shape Characteristics ◽  
Different Origins

The minimum void ratio is a fundamental physical index for evaluating particle properties in soil mechanics, ceramic processing, and concrete mixes. Previous research found that both particle size distribution and particle shape characteristics would affect minimum void ratio, while the current research generally uses a linear model to estimate the minimum void ratio of a binary mixture, ignoring quantitative effect of particle shape on the minimum void ratio. Based on a study of binary mixtures of natural sand from three different origins and iron particles of two different shapes, this paper analyzes the influence factors of the minimum void ratio, and a quadratic nonlinear model is proposed for estimating the minimum void ratio of binary mixture. The model contains only one undetermined coefficient, a, the value of which is correlated to the particle sphericity, particle size, and particle size ratio. A theoretical calculation formula for the coefficient a is proposed to quantitatively analyze the effects of these three factors on the size of the parameters. In the end, the model is used to estimate the minimum void ratios of sand and substitute particles from different producing areas; the average difference between the estimated values and the fitted values is about 2.03%, suggesting that the estimated values of the model fit well with the measured data.

scholarly journals Shape Characteristics of Coral Sand from the South China Sea

2020 ◽  
Vol 8 (10) ◽  
pp. 803 ◽  
Author(s):  
Xing Wang ◽  
Yang Wu ◽  
Jie Cui ◽  
Chang-Qi Zhu ◽  
Xin-Zhi Wang
Keyword(s):  
Particle Size ◽  
Bulk Density ◽  
Quartz Sand ◽  
Particle Shape ◽  
Fractal Theory ◽  
Skewed Distribution ◽  
Shape Parameters ◽  
Coral Sand ◽  
Particle Images ◽  
Shape Characteristics

The particle shape of coral sand is a crucial factor that affects its accumulation characteristics. Two-dimensional particle images of coral sand with different particle sizes were obtained through optical imaging, and the basic size parameters of particles were measured by digital image processing. The particle shape parameters were created, and on this basis, the variation of shape parameters with size, the distribution characteristics, and the sensitivity of shape parameters were analyzed by mathematical statistics and the fractal theory. In addition, a comparative analysis was conducted for the particle shape and bulk density of coral sand and quartz sand with the same particle size. The results show that (1) for coral sand with particle size ranging from 0.5 to 5.0 mm, as the particle size augments, its overall profile coefficient grows, while the flatness, angularity, and roughness diminish and the particle shape deviates more from the regular circle. (2) The shape of coral sand particles exhibits good fractal characteristics, and the particle shape gets more complex as the particle size grows as evidenced by the fact that the fractal dimension enlarges. (3) All the shape parameters obey a skewed distribution. Concerning the sensitivity to the change in particle shape, the flatness occupies the first place, the overall profile coefficient and angularity come second, and the roughness ranks third, accordingly. It is suggested that flatness should be preferred as the evaluation parameter of the particle shape. (4) Compared with that of quartz sand, the particle shape of coral sand is more irregular, and the intergranular pores are larger under the same accumulation conditions, which is the primary reason why the specific gravity of coral sand is greater than that of quartz sand while the bulk density is smaller than that of quartz sand.

Anisotropic Resilient Modulus Model of Granular Materials Based on Particle Characteristics

2021 ◽  
pp. 036119812110237
Author(s):  
Zefeng Tao ◽  
Zengyi Wang ◽  
Jianming Ling ◽  
Yu Tian ◽  
Juewei Cai ◽  
...  
Keyword(s):  
Particle Size ◽  
Granular Materials ◽  
Particle Shape ◽  
Resilient Modulus ◽  
Design Procedure ◽  
Triaxial Tests ◽  
Model Parameters ◽  
Anisotropic Particles ◽  
Particle Characteristics ◽  
Shape Characteristics

Granular materials are widely used for bases or subbases in pavement structures. They typically exhibit strong anisotropic properties which relate to stress states and particle characteristics. The conventional design procedure for flexible pavements underestimates the anisotropy of resilient moduli. This study established an anisotropic resilient modulus model for granular materials that considered gradation and particle shape characteristics. Vertical and horizontal resilient moduli of certain granular materials were measured in self-developed triaxial tests to obtain corresponding model parameters and anisotropic coefficients. Gradation and particle shape models were established to quantify the granular material characteristics, and the parameters were regressed. Particle shapes were obtained via image processing, and the ratio ( η) of particle sphericity to roundness was chosen as a shape parameter. Results show that η increases with the decrease in particle size, and the average values of η for graded gravel and natural laterite are 0.54 and 0.63, respectively. The η distribution curves indicate that the proportion of relatively anisotropic particles, rather than extremely anisotropic particles, results in the differences in particle shape characteristics. The regression relationship between the anisotropic calculation parameters and the model parameters of vertical resilient modulus, gradation, and particle shape was established. Thus, the horizontal resilient modulus and the anisotropic coefficient can be predicted via conventional resilient modulus tests and gradation, and particle shape analysis. This study shows that the anisotropy of granular materials decreases with the increase in coarse particles and the uniformization of the particle size distribution, and it increases with the increase in anisotropic particles and the polarization of the η distribution.

Phase behavior of a binary mixture of patchy colloids: Effect of particle size and gravity

2021 ◽  
Vol 155 (4) ◽  
pp. 044903
Author(s):  
Rodrigo Braz Teixeira ◽  
Daniel de las Heras ◽  
José Maria Tavares ◽  
Margarida M. Telo da Gama
Keyword(s):  
Particle Size ◽  
Binary Mixture ◽  
Phase Behavior ◽  
Effect Of Particle Size ◽  
Patchy Colloids

Modelling Particle Size Distribution of Residual Fly Ash from Pulverized Biomass Combustion

2021 ◽  
Vol 15 (1) ◽  
pp. 75-82
Author(s):  
Mingzi Xu ◽  
Changdong Sheng
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Simple Model ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Great Influence ◽  
Biomass Combustion ◽  
Ash Formation ◽  
Residual Ash

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.

scholarly journals EFFECTS OF PARTICLE SIZE AND PARTICLE SHAPE IN FLOW SIMULATIONS OF DRY SAND USING DEM

2015 ◽  
Vol 71 (2) ◽  
pp. I_587-I_594
Author(s):  
Shuji MORIGUCHI ◽  
Yuta HIRUMA ◽  
Shinsuke TAKASE ◽  
Kenjiro TERADA
Keyword(s):  
Particle Size ◽  
Particle Shape ◽  
Flow Simulations ◽  
Dry Sand

scholarly journals Optimization of nanostructured/nano sized rice husk ash preparation

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Particle Shape ◽  
Rice Husk Ash ◽  
Loss On Ignition ◽  
Shape Distribution ◽  
Disk Mill ◽  
Grinding Time

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

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